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Sample records for chitin

  1. Chitin Degradation In Marine Bacteria

    DEFF Research Database (Denmark)

    Paulsen, Sara; Machado, Henrique; Gram, Lone

    2015-01-01

    Introduction: Chitin is the most abundant polymer in the marine environment and the second most abundant in nature. Chitin does not accumulate on the ocean floor, because of microbial breakdown. Chitin degrading bacteria could have potential in the utilization of chitin as a renewable carbon...... and nitrogen source in the fermentation industry.Methods: Here, whole genome sequenced marine bacteria were screened for chitin degradation using phenotypic and in silico analyses.Results: The in silico analyses revealed the presence of three to nine chitinases in each strain, however the number of chitinases...... chitin regulatory system.Conclusions: This study has provided insight into the ecology of chitin degradation in marine bacteria. It also served as a basis for choosing a more efficient chitin degrading production strain e.g. for the use of chitin waste for large-scale fermentations....

  2. Chitin fulfilling a biomaterials promise

    CERN Document Server

    Khor, Eugene

    2001-01-01

    The second edition of Chitin underscores the important factors for standardizing chitin processing and characterization. It captures the essential interplay between chitin's assets and limitations as a biomaterial, placing the past promises of chitin in perspective, addressing its present realities and offering insight into what is required to realize chitin's destiny (including its derivative, chitosan) as a biomaterial of the twenty-first century. This book is an ideal guide for both industrialists and researchers with a vested interest in commercializing chitin.An upd

  3. Chitin-based Nanocomposites

    Institute of Scientific and Technical Information of China (English)

    D.K.Polyakov; S.N.Chvalun

    2007-01-01

    1 Results The one of the promising development of biodegradable nanocomposites is using native polysaccharides which have pronounced fibril structure to provide not only excellent mechanical properties and biodegradability of produced material but also control the barrier properties, for example increasing selectivity of pervaporation membrane. Chitin is the most popular biopolymer in the nature after cellulose. It is the 2-acetoamido-derivative of cellulose and serves as the fibrous component of the sk...

  4. Chitin modulates innate immune responses of keratinocytes.

    Directory of Open Access Journals (Sweden)

    Barbara Koller

    Full Text Available BACKGROUND: Chitin, after cellulose the second most abundant polysaccharide in nature, is an essential component of exoskeletons of crabs, shrimps and insects and protects these organisms from harsh conditions in their environment. Unexpectedly, chitin has been found to activate innate immune cells and to elicit murine airway inflammation. The skin represents the outer barrier of the human host defense and is in frequent contact with chitin-bearing organisms, such as house-dust mites or flies. The effects of chitin on keratinocytes, however, are poorly understood. METHODOLOGY/PRINCIPAL FINDINGS: We hypothesized that chitin stimulates keratinocytes and thereby modulates the innate immune response of the skin. Here we show that chitin is bioactive on primary and immortalized keratinocytes by triggering production of pro-inflammatory cytokines and chemokines. Chitin stimulation further induced the expression of the Toll-like receptor (TLR TLR4 on keratinocytes at mRNA and protein level. Chitin-induced effects were mainly abrogated when TLR2 was blocked, suggesting that TLR2 senses chitin on keratinocytes. CONCLUSIONS/SIGNIFICANCE: We speculate that chitin-bearing organisms modulate the innate immune response towards pathogens by upregulating secretion of cytokines and chemokines and expression of MyD88-associated TLRs, two major components of innate immunity. The clinical relevance of this mechanism remains to be defined.

  5. Chitin nanofibers: preparations, modifications, and applications

    Science.gov (United States)

    Ifuku, Shinsuke; Saimoto, Hiroyuki

    2012-05-01

    Chitin nanofibers are prepared from the exoskeletons of crabs and prawns by a simple mechanical treatment after the removal of proteins and minerals. The obtained nanofibers have fine nanofiber networks with a uniform width of approximately 10-20 nm and a high aspect ratio. The method used for chitin-nanofiber isolation is also successfully applied to the cell walls of mushrooms. They form a complex with glucans on the fiber surface. A grinder, a Star Burst atomization system, and a high speed blender are all used in the mechanical treatment to convert chitin to nanofibers. Mechanical treatment under acidic conditions is the key to facilitate fibrillation. At pH 3-4, the cationization of amino groups on the fiber surface assists nano-fibrillation by electrostatic repulsive force. By applying this finding, we also prepared chitin nanofibers from dry chitin powder. Chitin nanofibers are acetylated to modify their surfaces. The acetyl DS can be controlled from 1 to 3 by changing the reaction time. An acetyl group is introduced heterogeneously from the surface to the core. Nanofiber morphology is maintained even in the case of high acetyl DS. Optically transparent chitin nanofiber composites are prepared with 11 different types of acrylic resins. Due to the nano-sized structure, all of the composites are highly transparent. Chitin nanofibers significantly increase the Young's moduli and the tensile strengths and decrease the thermal expansion of all acrylic resins due to the reinforcement effect of chitin nanofibers. Chitin nanofibers show chiral separation ability. The chitin nanofiber membrane transports the d-isomer of glutamic acid, phenylalanine, and lysine from the corresponding racemic amino acid mixtures faster than the corresponding l-isomer. The chitin nanofibers improve clinical symptoms and suppress ulcerative colitis in a DSS-induced mouse model of acute ulcerative colitis. Moreover, chitin nanofibers suppress myeloperoxidase activation in the colon and

  6. In situ microscopic observation of chitin and fungal cells with chitinous cell walls in hydrothermal conditions

    OpenAIRE

    Shigeru Deguchi; Kaoru Tsujii; Koki Horikoshi

    2015-01-01

    Recent findings of intact chitin in fossil records suggest surprisingly high recalcitrance of this biopolymer during hydrothermal treatments. We also know in the experience of everyday life that mushroom, cells of which have chitinous cell walls, do not fall apart however long they are simmered. We used in situ optical microscopy to examine chitin and fungal cells with chitinous cell walls during hydrothermal treatments, and obtained direct evidence that they remained undegraded at temperatur...

  7. Physicochemical Characterization and the Comparison of Chitin and Chitin Modified with Maleic Anhydride

    OpenAIRE

    İlhan Uzun; Ömer Çelik

    2015-01-01

    Firstly, chitin was modified via ring-opening reaction with maleic anhydride in lithium chloride/N,N-dimethylacetamide. Then, both chitin and chitin modified with maleic anhydride (CMA) were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) method, ultraviolet-visible (UV-Vis) spectroscopy, and scanning electron microscopy (SEM). Thermogravimetric analysis (TGA) was performed to investigate the thermal stability of chitin and CMA. TGA results showed that...

  8. Differentiations of chitin content and surface morphologies of chitins extracted from male and female grasshopper species.

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    Murat Kaya

    Full Text Available In this study, we used Fourier transform infrared spectroscopy (FT-IR, elemental analysis (EA, thermogravimetric analysis (TGA, X-ray diffractometry (XRD, and scanning electron microscopy (SEM to investigate chitin structure isolated from both sexes of four grasshopper species. FT-IR, EA, XRD, and TGA showed that the chitin was in the alpha form. With respect to gender, two main differences were observed. First, we observed that the quantity of chitin was greater in males than in females and the dry weight of chitin between species ranged from 4.71% to 11.84%. Second, using SEM, we observed that the male chitin surface structure contained 25-90 nm wide nanofibers and 90-250 nm nanopores, while no pores or nanofibers were observed in the chitin surface structure of the majority of females (nanofibers were observed only in M. desertus females. In contrast, the elemental analysis, thermal properties, and crystalline index values for chitin were similar in males and females. Also, we carried out enzymatic digestion of the isolated chitins using commercial chitinase from Streptomyces griseus. We observed that there were no big differences in digestion rate of the chitins from both sexes and commercial chitin. The digestion rates were for grasshoppers' chitins; 88.45-95.48% and for commercial chitin; 94.95%.

  9. Chitin nanofiber elucidates the elicitor activity of polymeric chitin in plants

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    Mayumi eEgusa

    2015-12-01

    Full Text Available Chitin, an N-acetyl-D-glucosamine polymer, is a component of fungal cell walls and a microbe/pathogen-associated molecular pattern that elicits plant defense responses. As polymeric chitin is difficult to handle due to its insolubility in water, many studies on chitin-induced immune responses have used water-soluble low-molecular weight chitin instead. Thus, it is unclear if polymeric chitin can induce resistance. Here, we examined the elicitor activity of chitin nanofiber (CNF of submicron thickness prepared from polymeric chitin. CNF showed a high dispersing ability in water and induced both reactive oxygen species (ROS production and chitin-induced defense-related gene expression in Arabidopsis thaliana seedlings. The Arabidopsis chitin elicitor receptor kinase 1 (Atcerk1 mutant, which is impaired in chitin perception, also failed to respond to CNF. CNF exposure triggered ROS generation in suspension-cultured cells from Oryza sativa. Furthermore, pre-treatment of Arabidopsis leaves with CNF effectively reduced pathogen infection by both the fungus Alternaria brassicicola and the bacterium Pseudomonas syringae pv. tomato DC3000. These results demonstrate that CNF has elicitor activity and will help define the role of polymeric chitin in plant immune responses.

  10. Physicochemical Characterization and the Comparison of Chitin and Chitin Modified with Maleic Anhydride

    Directory of Open Access Journals (Sweden)

    İlhan Uzun

    2015-06-01

    Full Text Available Firstly, chitin was modified via ring-opening reaction with maleic anhydride in lithium chloride/N,N-dimethylacetamide. Then, both chitin and chitin modified with maleic anhydride (CMA were characterized by Fourier transform infrared (FTIR spectroscopy, X-ray diffraction (XRD method, ultraviolet-visible (UV-Vis spectroscopy, and scanning electron microscopy (SEM. Thermogravimetric analysis (TGA was performed to investigate the thermal stability of chitin and CMA. TGA results showed that chitin is thermally more stable than CMA. In addition, the electrical conductivity of chitin and CMA was also measured. Electrical conductivity measurement results showed that the electrical conductivity of CMA (4.3x10-4 S cm-1 is more than that of chitin (6.5x10-6 S cm-1.

  11. Physicochemical behaviour of chitin gels.

    Science.gov (United States)

    Vachoud, L; Zydowicz, N; Domard, A

    2000-06-30

    Syneresis of chitin gels formed in the course of N-acetylation of chitosan in hydroalcoholic media has been studied. A critical cross-linking density related to a critical acetylation degree for which the gel undergoes weak syneresis and swells in water was shown (degree of acetylation (DA) 88%). Above this value, the weight loss during syneresis increases with DA. Conversely, syneresis decreases on increasing the polymer concentration, but disappears at a macroscopic level for a polymer concentration close to the critical concentration of entanglement in the initial solution. An increase in temperature favours the formation of hydrophobic interactions and new inter- and intramolecular hydrogen bondings. Due to the weak polyelectrolyte character of chitin, the weight of the gel depends on the pH and ionic strength of the media. Swelling-deswelling experiments show that the swelling of the gel is not fully reversible in relation with the formation of new cross-links during the depletion of the network. Our results reveals that the balance between segment-segment and segment-solvent interactions as well as the molecular mobility play the major role.

  12. Fabrication of optically transparent chitin nanocomposites

    Science.gov (United States)

    Shams, M. Iftekhar; Ifuku, Shinsuke; Nogi, Masaya; Oku, Takeshi; Yano, Hiroyuki

    2011-02-01

    This paper demonstrates the preparation of chitin nanofibers from crab shells using a simple mechanical treatment. The nanofibers are small enough to retain the transparency of neat acrylic resin. Possessing hydroxyl and amine/ N-acetyl functionalities, water suspension of chitin nanofibers was vacuum-filtered 9 times faster than cellulose nanofibers to prepare a nanofiber sheet of 90 mm in diameter. This is a prominent advantage of chitin nanofibers over cellulose nanofibers in terms of commercial application. Interestingly, chitin acrylic resin films exhibited much higher transparency than cellulose acrylic resin films owing to the close affinity between less hydrophilic chitin and hydrophobic resin. Furthermore, the incorporation of chitin nanofibers contributes to the significant improvement of the thermal expansion and mechanical properties of the neat acrylic resin. The properties of high light transmittance and low thermal expansion make chitin nanocomposites promising candidates for the substrate in a continuous roll-to-roll process in the manufacturing of various optoelectronic devices such as flat panel displays, bendable displays, and solar cells.

  13. A Selective Assay to Detect Chitin and Biologically Active Nano-Machineries for Chitin-Biosynthesis with Their Intrinsic Chitin-Synthase Molecules

    Directory of Open Access Journals (Sweden)

    Hildgund Schrempf

    2010-09-01

    Full Text Available A new assay system for chitin has been developed. It comprises the chitin-binding protein ChbB in fusion with a His-tag as well as with a Strep-tag, the latter of which was chemically coupled to horseradish peroxidase. With the resulting complex, minimal quantities of chitin are photometrically detectable. In addition, the assay allows rapid scoring of the activity of chitin-synthases. As a result, a refined procedure for the rapid purification of yeast chitosomes (nano-machineries for chitin biosynthesis has been established. Immuno-electronmicroscopical studies of purified chitosomes, gained from a yeast strain carrying a chitin-synthase gene fused to that for GFP (green-fluorescence protein, has led to the in situ localization of chitin-synthase-GFP molecules within chitosomes.

  14. Perspectives of Chitin and Chitosan Nanofibrous Scaffolds in Tissue Engineering

    OpenAIRE

    Jayakumar, R.; Nair, S. V.; Furuike, T.; Tamura, H.

    2010-01-01

    This review summarized the preparation and tissue engineering applications of chitin and chitosan based nanofibers. Additional studies are necessary before clinical applications and for commercialization of the chitin and chitosan based nanofibers. We hope that this review article will bring new innovative types of chitin and chitosan nanofibers for tissue engineering applications in the future.

  15. Biodegradation of the chitin-protein complex in crustacean cuticle

    Science.gov (United States)

    Artur, Stankiewicz B.; Mastalerz, Maria; Hof, C.H.J.; Bierstedt, A.; Flannery, M.B.; Briggs, D.E.G.; Evershed, R.P.

    1998-01-01

    Arthropod cuticles consist predominantly of chitin cross-linked with proteins. While there is some experimental evidence that this chitin-protein complex may resist decay, the chemical changes that occur during degradation have not been investigated in detail. The stomatopod crustacean Neogonodactylus oerstedii was decayed in the laboratory under anoxic conditions. A combination of pyrolysis-gas chromatography/mass spectrometry and FTIR revealed extensive chemical changes after just 2 weeks that resulted in a cuticle composition dominated by chitin. Quantitative analysis of amino acids (by HPLC) and chitin showed that the major loss of proteins and chitin occurred between weeks 1 and 2. After 8 weeks tyrosine, tryptophan and valine are the most prominent amino acid moieties, showing their resistance to degradation. The presence of cyclic ketones in the pyrolysates indicates that mucopolysaccharides or other bound non-chitinous carbohydrates are also resistant to decay. There is no evidence of structural degradation of chitin prior to 8 weeks when FTIR revealed a reduction in chitin-specific bands. The chemical changes are paralleled by structural changes in the cuticle, which becomes an increasingly open structure consisting of loose chitinous fibres. The rapid rate of decay in the experiments suggests that where chitin and protein are preserved in fossil cuticles degradation must have been inhibited.Arthropod cuticles consist predominantly of chitin cross-linked with proteins. While there is some experimental evidence that this chitin-protein complex may resist decay, the chemical changes that occur during degradation have not been investigated in detail. The stomatopod crustacean Neogonodactylus oerstedii was decayed in the laboratory under anoxic conditions. A combination of pyrolysis-gas chromatography/mass spectrometry and FTIR revealed extensive chemical changes after just 2 weeks that resulted in a cuticle composition dominated by chitin. Quantitative

  16. Preparation of chitin nanofibers by surface esterification of chitin with maleic anhydride and mechanical treatment.

    Science.gov (United States)

    Aklog, Yihun Fantahun; Nagae, Tomone; Izawa, Hironori; Morimoto, Minoru; Saimoto, Hiroyuki; Ifuku, Shinsuke

    2016-11-20

    Esterification with maleic anhydride significantly improved the mechanical disintegration of chitin into uniform 10-nm nanofibers. Nanofibers with 0.25° of esterification were homogeneously dispersed in basic water due to the carboxylate salt on the surface. Esterification proceeded on the surface and did not affect the relative crystallinity. A cast film of the esterified chitin nanofibers was highly transparent, since the film was free from light scattering. PMID:27561471

  17. Poriferan chitin as a template for hydrothermal zirconia deposition

    Science.gov (United States)

    Wysokowski, Marcin; Motylenko, Mykhaylo; Bazhenov, Vasilii V.; Stawski, Dawid; Petrenko, Iaroslav; Ehrlich, Andre; Behm, Thomas; Kljajic, Zoran; Stelling, Allison L.; Jesionowski, Teofil; Ehrlich, Hermann

    2013-09-01

    Chitin is a thermostable biopolymer found in various inorganic-organic skeletal structures of numerous invertebrates including sponges (Porifera). The occurrence of chitin within calcium- and silica-based biominerals in organisms living in extreme natural conditions has inspired development of new (extreme biomimetic) synthesis route of chitin-based hybrid materials in vitro. Here, we show for the first time that 3D-α-chitin scaffolds isolated from skeletons of the marine sponge Aplysina aerophoba can be effectively mineralized under hydrothermal conditions (150°C) using ammonium zirconium(IV) carbonate as a precursor of zirconia. Obtained chitin-ZrO2 hybrid materials were characterized by FT-IR, SEM, HRTEM, as well as light and confocal laser microscopy. We suggest that formation of chitin-ZrO2 hybrids occurs due to hydrogen bonds between chitin and ZrO2.

  18. DNA extraction from keratin and chitin.

    Science.gov (United States)

    Campos, Paula F; Gilbert, Thomas M P

    2012-01-01

    DNA extracted from keratinous and chitinous materials can be a useful source of genetic information. To effectively liberate the DNA from these materials, buffers containing relatively high levels of DTT, proteinase K, and detergent are recommended, followed by purification using either silica-column or organic methods.

  19. Chitin: 'Forgotten' Source of Nitrogen: From Modern Chitin to Thermally Mature Kerogen: Lessons from Nitrogen Isotope Ratios

    Science.gov (United States)

    Schimmelmann, A.; Wintsch, R.P.; Lewan, M.D.; DeNiro, M.J.

    1998-01-01

    Chitinous biomass represents a major pool of organic nitrogen in living biota and is likely to have contributed some of the fossil organic nitrogen in kerogen. We review the nitrogen isotope biogeochemistry of chitin and present preliminary results suggesting interaction between kerogen and ammonium during thermal maturation. Modern arthropod chitin may shift its nitrogen isotope ratio by a few per mil depending on the chemical method of chitin preparation, mostly because N-containing non-amino-sugar components in chemically complex chitin cannot be removed quantitatively. Acid hydrolysis of chemically complex chitin and subsequent ion-chromatographic purification of the "deacetylated chitin-monomer" D-glucosamine (in hydrochloride form) provides a chemically well-defined, pure amino-sugar substrate for reproducible, high-precision determination of ??15N values in chitin. ??15N values of chitin exhibited a variability of about one per mil within an individual's exoskeleton. The nitrogen isotope ratio differed between old and new exoskeletons by up to 4 per mil. A strong dietary influence on the ??15N value of chitin is indicated by the observation of increasing ??15N values of chitin from marine crustaceans with increasing trophic level. Partial biodegradation of exoskeletons does not significantly influence ??15N values of remaining, chemically preserved amino sugar in chitin. Diagenesis and increasing thermal maturity of sedimentary organic matter, including chitin-derived nitrogen-rich moieties, result in humic compounds much different from chitin and may significantly change bulk ??15N values. Hydrous pyrolysis of immature source rocks at 330??C in contact with 15N-enriched NH4Cl, under conditions of artificial oil generation, demonstrates the abiogenic incorporation of inorganic nitrogen into carbon-bound nitrogen in kerogen. Not all organic nitrogen in natural, thermally mature kerogen is therefore necessarily derived from original organic matter, but may

  20. Preparation and biomedical applications of chitin and chitosan nanofibers.

    Science.gov (United States)

    Azuma, Kazuo; Ifuku, Shinsuke; Osaki, Tomohiro; Okamoto, Yoshiharu; Minami, Saburo

    2014-10-01

    Chitin (β-(1-4)-poly-N-acetyl-D-glucosamine) is widely distributed in nature and is the second most abundant polysaccharide after cellulose. Chitin occurs in nature as ordered macrofibrils. It is the major structural component in the exoskeleton of crab and shrimp shells and the cell wall of fungi and yeast. As chitin is not readily dissolved in common solvents, it is often converted to its more deacetylated derivative, chitosan. Chitin, chitosan, and its derivatives are widely used in tissue engineering, wound healing, and as functional foods. Recently, easy methods for the preparation of chitin and chitosan nanofibers have been developed, and studies on biomedical applications of chitin and chitosan nanofibers are ongoing. Chitin and chitosan nanofibers are considered to have great potential for various biomedical applications, because they have several useful properties such as high specific surface area and high porosity. This review summarizes methods for the preparation of chitin and chitosan nanofibers. Further, biomedical applications of chitin and chitosan nanofibers in (i) tissue engineering, (ii) wound dressing, (iii) cosmetic and skin health, (iv) stem cell technology, (v) anti-cancer treatments and drug delivery, (vi) anti-inflammatory treatments, and (vii) obesity treatment are summarized. Many studies indicate that chitin and chitosan nanofibers are suitable materials for various biomedical applications.

  1. Characterization of genes for chitin catabolism in Haloferax mediterranei.

    Science.gov (United States)

    Hou, Jing; Han, Jing; Cai, Lei; Zhou, Jian; Lü, Yang; Jin, Cheng; Liu, Jingfang; Xiang, Hua

    2014-02-01

    Chitin is the second most abundant natural polysaccharide after cellulose. But degradation of chitin has never been reported in haloarchaea. In this study, we revealed that Haloferax mediterranei, a metabolically versatile haloarchaeon, could utilize colloidal or powdered chitin for growth and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) accumulation, and the gene cluster (HFX_5025-5039) for the chitin catabolism pathway was experimentally identified. First, reverse transcription polymerase chain reaction results showed that the expression of the genes encoding the four putative chitinases (ChiAHme, ChiBHme, ChiCHme, and ChiDHme, HFX_5036-5039), the LmbE-like deacetylase (DacHme, HFX_5027), and the glycosidase (GlyAHme, HFX_5029) was induced by colloidal or powdered chitin, and chiA Hme, chiB Hme, and chiC Hme were cotranscribed. Knockout of chiABC Hme or chiD Hme had a significant effect on cell growth and PHBV production when chitin was used as the sole carbon source, and the chiABCD Hme knockout mutant lost the capability to utilize chitin. Knockout of dac Hme or glyA Hme also decreased PHBV accumulation on chitin. These results suggested that ChiABCDHme, DacHme, and GlyAHme were indeed involved in chitin degradation in H. mediterranei. Additionally, the chitinase assay showed that each chitinase possessed hydrolytic activity toward colloidal or powdered chitin, and the major product of colloidal chitin hydrolysis by ChiABCDHme was diacetylchitobiose, which was likely further degraded to monosaccharides by DacHme, GlyAHme, and other related enzymes for both cell growth and PHBV biosynthesis. Taken together, this study revealed the genes and enzymes involved in chitin catabolism in haloarchaea for the first time and indicated the potential of H. mediterranei as a whole-cell biocatalyst in chitin bioconversion.

  2. Biosynthesis, Turnover, and Functions of Chitin in Insects.

    Science.gov (United States)

    Zhu, Kun Yan; Merzendorfer, Hans; Zhang, Wenqing; Zhang, Jianzhen; Muthukrishnan, Subbaratnam

    2016-01-01

    Chitin is a major component of the exoskeleton and the peritrophic matrix of insects. It forms complex structures in association with different assortments of cuticle and peritrophic matrix proteins to yield biocomposites with a wide range of physicochemical and mechanical properties. The growth and development of insects are intimately coupled with the biosynthesis, turnover, and modification of chitin. The genes encoding numerous enzymes of chitin metabolism and proteins that associate with and organize chitin have been uncovered by bioinformatics analyses. Many of these proteins are encoded by sets of large gene families. There is specialization among members within each family, which function in particular tissues or developmental stages. Chitin-containing matrices are dynamically modified at every developmental stage and are under developmental and/or physiological control. A thorough understanding of the diverse processes associated with the assembly and turnover of these chitinous matrices offers many strategies to achieve selective pest control. PMID:26982439

  3. Chitin and Chitosan as Direct Compression Excipients in Pharmaceutical Applications

    Directory of Open Access Journals (Sweden)

    Adnan A. Badwan

    2015-03-01

    Full Text Available Despite the numerous uses of chitin and chitosan as new functional materials of high potential in various fields, they are still behind several directly compressible excipients already dominating pharmaceutical applications. There are, however, new attempts to exploit chitin and chitosan in co-processing techniques that provide a product with potential to act as a direct compression (DC excipient. This review outlines the compression properties of chitin and chitosan in the context of DC pharmaceutical applications.

  4. Wet spinning of fibers made of chitosan and chitin nanofibrils.

    Science.gov (United States)

    Yudin, Vladimir E; Dobrovolskaya, Irina P; Neelov, Igor M; Dresvyanina, Elena N; Popryadukhin, Pavel V; Ivan'kova, Elena M; Elokhovskii, Vladimir Yu; Kasatkin, Igor A; Okrugin, Boris M; Morganti, Pierfrancesco

    2014-08-01

    Biocompatible and bioresorbable composite fibers consisting of chitosan filled with anisotropic chitin nanofibrils with the length of 600-800 nm and cross section of about 11-12 nm as revealed by SEM and XRD were prepared by coagulation. Both chitin and chitosan components of the composite fibers displayed preferred orientations. Orientation of chitosan molecules induced by chitin nanocrystallites was confirmed by molecular modeling. The incorporation of 0.1-0.3 wt.% of chitin nanofibrils into chitosan matrix led to an increase in strength and Young modulus of the composite fibers. PMID:24751262

  5. La chitine dans le règne animal

    OpenAIRE

    Jeuniaux, Charles

    1982-01-01

    La chitine, haut polymère linéaire B-1,4 de la N-acétyl-D-glucosamine, est largement utilisée dans le règne animal comme trame organique de structures exosquelettiques et cuticulaires. Une méthode enzymatique, rigoureusement spécifique, permet de déceler la chitine, de mesurer son importance quantitative, et de reconnaître l'existence de liaisons avec d'autres constituants (chitine "masquée" et chitine "libre"). Elle se présente principalement sous forme de microfibrilles (complexes glycopro...

  6. Enhanced levan production using chitin-binding domain fused levansucrase immobilized on chitin beads.

    Science.gov (United States)

    Chiang, Chung-Jen; Wang, Jen-You; Chen, Po-Ting; Chao, Yun-Peng

    2009-03-01

    Levan is a homopolymer of fructose which can be produced by the transfructosylation reaction of levansucrase (EC 2.4.1.10) from sucrose. In particular, levan synthesized by Zymomonas mobilis has found a wide and potential application in the food and pharmaceutical industry. In this study, the immobilization of Z. mobilis levansucrae (encoded by levU) was attempted for repeated production of levan. By fusion levU with the chitin-binding domain (ChBD), the hybrid protein was overproduced in a soluble form in Escherichia coli. After direct absorption of the protein mixture from E. coli onto chitin beads, levansucrase tagged with ChBD was found to specifically attach to the affinity matrix. Subsequent analysis indicated that the linkage between the enzyme and chitin beads was substantially stable. Furthermore, with 20% sucrose, the production of levan was enhanced by 60% to reach 83 g/l using the immobilized levansucrase as compared to that by the free counterpart. This production yield accounts for 41.5% conversion yield (g/g) on the basis of sucrose. After all, a total production of levan with 480 g/l was obtained by recycling of the immobilized enzyme for seven times. It is apparent that this approach offers a promising way for levan production by Z. mobilis levansucrase immobilized on chitin beads. PMID:19018526

  7. Chitin and chitosan as functional biopolymers for industrial applications

    NARCIS (Netherlands)

    kardas, I.; Struzczyk, M.H.; Kucharska, M.; Broek, van den L.A.M.; Dam, van J.E.G.

    2012-01-01

    Chitin research and development seems to be under intensive progress during the last years. Attractive properties of chitin and its derivative—chitosan, for example, biological behavior, and development of their applications caused increased interest of scientists and companies. More and more practi

  8. STRUCTURAL FEATURES OF PLANT CHITINASES AND CHITIN-BINDING PROTEINS

    NARCIS (Netherlands)

    BEINTEMA, JJ

    1994-01-01

    Structural features of plant chitinases and chitin-binding proteins are discussed. Many of these proteins consist of multiple domains,of which the chitin-binding hevein domain is a predominant one. X-ray and NMR structures of representatives of the major classes of these proteins are available now,

  9. Thermal decomposition of natural polysaccharides: Chitin and chitosan

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    Kuchina Yu.A.

    2015-03-01

    Full Text Available The results of the thermal analysis of shrimp’s chitin and chitosan have been presented (samples of polysaccharide differed by the deacetylation degree have been studied. The thermal analysis has been carried out by differential thermogravimetry and differential scanning calorimetry. Activation energy of process of chitin and chitosan thermal destruction has been calculated

  10. Dielectric Relaxation Phenomena of Polylactic Acid with -Crystalline Chitin

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    Katsuyoshi Shinyama

    2012-01-01

    Full Text Available -crystalline chitin was added to polylactic acid (PLA, and this PLA was then heat-treated at 100∘C for one minute. The crystallinity of the heat-treated PLA increased to more than 40%, and its crystallization speed also increased significantly. The temperature dependency of these materials’ relative permittivity ( and relative dielectric loss factor ( was also examined. The dielectric absorption peak value in  curve of the PLA to which chitin was added and was smaller than that of PLA without chitin. Additionally, the Havriliak-Negami relaxation function was used to produce approximation curves for the frequency dependency of  and  of chitin with PLA added at 80∘C. As a result, the relaxation strength (Δ of the chitin with PLA added was smaller than that of the PLA without chitin, and the relaxation time ( of the chitin with PLA added was approximately 2.5 times larger than that of the PLA without chitin.

  11. Applications of Chitin and Its Derivatives in Biological Medicine

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    Moon-Moo Kim

    2010-12-01

    Full Text Available Chitin and its derivatives—as a potential resource as well as multiple functional substrates—have generated attractive interest in various fields such as biomedical, pharmaceutical, food and environmental industries, since the first isolation of chitin in 1811. Moreover, chitosan and its chitooligosaccharides (COS are degraded products of chitin through enzymatic and acidic hydrolysis processes; and COS, in particular, is well suited for potential biological application, due to the biocompatibility and nontoxic nature of chitosan. In this review, we investigate the current bioactivities of chitin derivatives, which are all correlated with their biomedical properties. Several new and cutting edge insights here may provide a molecular basis for the mechanism of chitin, and hence may aid its use for medical and pharmaceutical applications.

  12. Chitin synthesis inhibitors: old molecules and new developments

    Institute of Scientific and Technical Information of China (English)

    Hans Merzendorfer

    2013-01-01

    Chitin is the most abundant natural aminopolysaccharide and serves as a structural component of extracellular matrices.It is found in fungal septa,spores,and cell walls,and in arthropod cuticles and peritrophic matrices,squid pens,mollusk shells,nematode egg shells,and some protozoan cyst walls.As prokaryotes,plants and vertebrates including humans do not produce chitin,its synthesis is considered as an attractive target site for fungicides,insecticides,and acaricides.Although no chitin synthesis inhibitor has been developed into a therapeutic drug to treat fungal infections in humans,a larger number of compounds have been successfully launched worldwide to combat arthropod pests in agriculture and forestry.This review summarizes the latest advances on the mode of action of chitin synthesis inhibitors with a special focus on those molecules that act on a postcatalytic step of chitin synthesis.

  13. Granular chitin in the epidermis of nudibranch molluscs.

    Science.gov (United States)

    Martin, Rainer; Hild, Sabine; Walther, Paul; Ploss, Kerstin; Boland, Wilhelm; Tomaschko, Karl-Heinz

    2007-12-01

    Chitin is usually found in stiff extracellular coatings typified by the arthropod exoskeleton, and is not associated with the soft, flexible mollusc skin. Here, we show, however, that chitin in nudibranch gastropods (Opisthobranchia, Mollusca) occurs as intracellular granules that fill the epidermal cells of the skin and the epithelial cells of the stomach. In response to nematocysts fired by tentacles of prey Cnidaria, the epidermal cells of eolid nudibranchs (Aeolidacea) release masses of chitin granules, which then form aggregates with the nematocyst tubules, having the effect of insulating the animal from the deleterious action of the Cnidaria tentacles. Granular chitin, while protecting the animal, does not interfere with the suppleness and flexibility of the skin, in contrast to the stiffness of chitin armor. The specialized epidermis enables nudibranchs to live with and feed on Cnidaria. PMID:18083970

  14. Degradation and mineralization of chitin in an estuary

    International Nuclear Information System (INIS)

    A method for measuring microbial degradation and mineralization of radiolabeled native chitin is described. 14C-labeled chitin was synthesized in vivo by injecting shed blue crabs (Callinectes sapidus) with N-acetyl-D-[14C]-glucosamine, allowing for its incorporation into the exoskeleton. Rates of chitin degradation and mineralization in estuarine water and sediments were determined as functions of temperature, inoculum source, and oxygen condition. Significant differences in rates between temperature treatments were evident. Q10 values ranged from 1.2 to 2.5 for water and sediment, respectively. Increased incubation temperature also resulted in decreased lag times before onset of chitinoclastic bacterial growth and chitin degradation. The anaerobic pathway of chitin decomposition by chitinoclastic bacteria was examined with an emphasis on end product coupling to other bacterial types. Actively growing chitinoclastic bacterial isolates produced primarily acetate, hydrogen, and carbon dioxide in broth culture

  15. The apical plasma membrane of chitin-synthesizing epithelia

    Institute of Scientific and Technical Information of China (English)

    Bernard Moussian

    2013-01-01

    Chitin is the second most abundant polysaccharide on earth.It is produced at the apical side of epidermal,tracheal,fore-,and hindgut epithelial cells in insects as a central component of the protective and supporting extracellular cuticle.Chitin is also an important constituent of the midgut peritrophic matrix that encases the food supporting its digestion and protects the epithelium against invasion by possibly ingested pathogens.The enzyme producing chitin is a glycosyltransferase that resides in the apical plasma membrane forming a pore to extrude the chains of chitin into the extracellular space.The apical plasma membrane is not only a platform for chitin synthases but,probably through its shape and equipment with distinct factors,also plays an important role in orienting and organizing chitin fibers.Here,I review findings on the cellular and molecular constitution of the apical plasma membrane of chitin-producing epithelia mainly focusing on work done in the fruit fly Drosophila melanogaster.

  16. Elevated Cell Wall Chitin in Candida albicans Confers Echinocandin Resistance In Vivo

    OpenAIRE

    Lee, K K; MacCallum, D.M; Jacobsen, M.D.; Walker, L A; Odds, F C; Gow, N. A. R.; Munro, C.A.

    2012-01-01

    Candida albicans cells with increased cell wall chitin have reduced echinocandin susceptibility in vitro. The aim of this study was to investigate whether C. albicans cells with elevated chitin levels have reduced echinocandin susceptibility in vivo. BALB/c mice were infected with C. albicans cells with normal chitin levels and compared to mice infected with high-chitin cells. Caspofungin therapy was initiated at 24 h postinfection. Mice infected with chitin-normal cells were successfully tre...

  17. DEVELOPMENT OF TECHNOLOGY OF PRODUCTION OF CHITIN FROM CRUSTACEANS WASTES

    OpenAIRE

    ALLAM AYMAN YOUNES FATHY; DOLGANOVA NATALIA VADIMOVNA

    2016-01-01

    The major sources of chitin production are sea crustaceans shrimps and crabs. In Egypt, the most economically justified source of chitin is green shrimp Penaeus semisulcatus, despite the fact that it can cause a significant pollution of the sea aquatorium. The aim of the study is to analyse the chemical composition of the crude shell of green shrimp and to develop the technology of producing chitin from this raw material. It has been found that the green shrimp shell contains 44.96% of alkali...

  18. Preparation and Grafting Functionalization of Self-Assembled Chitin Nanofiber Film

    Directory of Open Access Journals (Sweden)

    Jun-ichi Kadokawa

    2016-07-01

    Full Text Available Chitin is a representative biomass resource comparable to cellulose. Although considerable efforts have been devoted to extend novel applications to chitin, lack of solubility in water and common organic solvents causes difficulties in improving its processability and functionality. Ionic liquids have paid much attention as solvents for polysaccharides. However, little has been reported regarding the dissolution of chitin with ionic liquids. The author found that an ionic liquid, 1-allyl-3-methylimidazolium bromide (AMIMBr, dissolved chitin in concentrations up to ~4.8 wt % and the higher contents of chitin with AMIMBr gave ion gels. When the ion gel was soaked in methanol for the regeneration of chitin, followed by sonication, a chitin nanofiber dispersion was obtained. Filtration of the dispersion was subsequently carried out to give a chitin nanofiber film. A chitin nanofiber/poly(vinyl alcohol composite film was also obtained by co-regeneration approach. Chitin nanofiber-graft-synthetic polymer composite films were successfully prepared by surface-initiated graft polymerization technique. For example, the preparation of chitin nanofiber-graft-biodegradable polyester composite film was achieved by surface-initiated graft polymerization from the chitin nanofiber film. The similar procedure also gave chitin nanofiber-graft-polypeptide composite film. The surface-initiated graft atom transfer radical polymerization was conducted from a chitin macroinitiator film derived from the chitin nanofiber film.

  19. Application of chitin/chitosan in agriculture

    International Nuclear Information System (INIS)

    Chitosan is the deacetylated derivative of chitin and deacetylation degree is an important chemical characteristic which could be determined by HNMR or IR. spectroscopy. Chitosan of high deacetylation degree (87.37%) was oxidized by hydrogen peroxide at 0.6M concentration for 4 hours to obtain low molecular weight ∼ 6.0 x 104, further degradation was carried out by irradiation of chitosan in solution (4%, w/v) with gamma Co-60 rays, in the dose range from 10 kGy to 70 kGy. The test in the field for antifungus of Rhizoctonia Solani on rice plants was investigated. The antifungal effect of resultant chitosan at dose of 50 kGy and concentration of 80 ppm was most effective. (author)

  20. Multifilament cellulose/chitin blend yarn spun from ionic liquids.

    Science.gov (United States)

    Mundsinger, Kai; Müller, Alexander; Beyer, Ronald; Hermanutz, Frank; Buchmeiser, Michael R

    2015-10-20

    Cellulose and chitin, both biopolymers, decompose before reaching their melting points. Therefore, processing these unmodified biopolymers into multifilament yarns is limited to solution chemistry. Especially the processing of chitin into fibers is rather limited to distinctive, often toxic or badly removable solvents often accompanied by chemical de-functionalization to chitosan (degree of acetylation, DA, fibers using ionic liquids (ILs) as gentle, removable, recyclable and non-deacetylating solvents. Chitin and cellulose are dissolved in ethylmethylimidazolium propionate ([C2mim](+)[OPr](-)) and the obtained one-pot spinning dope is used to produce multifilament fibers by a continuous wet-spinning process. Both the rheology of the corresponding spinning dopes and the structural and physical properties of the obtained fibers have been determined for different biopolymer ratios. With respect to medical or hygienic application, the cellulose/chitin blend fiber show enhanced water retention capacity compared to pure cellulose fibers. PMID:26256157

  1. Adsorption studies of iron(III) on chitin

    Indian Academy of Sciences (India)

    G Karthikeyan; N Muthulakshmi Andal; K Anbalagan

    2005-11-01

    Adsorption of ferric ions by chitin was studied by the batch equilibration method. The influence of particle size and dosage of the adsorbant, contact time, initial concentration of the adsorbate and temperature were experimentally verified. The effect of anions like chloride, nitrate and sulphate and also of cations like zinc, chromium and copper on the adsorption of iron(III) was determined. The time dependence of fraction of adsorption, , at varying particle sizes and doses of chitin and the intraparticle diffusion rate constants, , of the adsorption process were calculated. Thermodynamic and equilibrium parameters of the reaction were determined to understand the sorption behaviour of chitin. The results revealed that the adsorption of iron(III) by chitin is spontaneous, endothermic and favourable.

  2. Emerging chitin and chitosan nanofibrous materials for biomedical applications

    Science.gov (United States)

    Ding, Fuyuan; Deng, Hongbing; Du, Yumin; Shi, Xiaowen; Wang, Qun

    2014-07-01

    Over the past several decades, we have witnessed significant progress in chitosan and chitin based nanostructured materials. The nanofibers from chitin and chitosan with appealing physical and biological features have attracted intense attention due to their excellent biological properties related to biodegradability, biocompatibility, antibacterial activity, low immunogenicity and wound healing capacity. Various methods, such as electrospinning, self-assembly, phase separation, mechanical treatment, printing, ultrasonication and chemical treatment were employed to prepare chitin and chitosan nanofibers. These nanofibrous materials have tremendous potential to be used as drug delivery systems, tissue engineering scaffolds, wound dressing materials, antimicrobial agents, and biosensors. This review article discusses the most recent progress in the preparation and application of chitin and chitosan based nanofibrous materials in biomedical fields.

  3. Dopamine-Mediated Sclerotization of Regenerated Chitin in Ionic Liquid

    Directory of Open Access Journals (Sweden)

    Dongyeop X. Oh

    2013-09-01

    Full Text Available Chitin is a promising structural material for biomedical applications, due to its many advantageous properties and abundance in nature. However, its usage and development in the biomedical field have been stagnant, because of chitin’s poor mechanical properties in wet conditions and the difficulties in transforming it into an applicable form. To overcome these challenges, we created a novel biomimetic chitin composite. This regenerated chitin, prepared with ionic liquid, showed improved mechanical properties in wet conditions by mimicking insect cuticle and squid beak sclerotization, i.e., catechol-meditated cross-linking. By ionic liquid-based heat treatment, dopamine oxidation produced melanin-like compounds and dopamine-meditated cross-links without any solvent evaporation and oxidant utilization. The dopamine-meditated sclerotization increased the ultimate tensile strength (UTS of the regenerated chitin by 2.52-fold, measured after six weeks of phosphate-buffered saline (PBS submersion. In addition, the linear swelling ratio (LSR of the chitin film was reduced by about 22%. This strategy raises a possibility of using regenerated chitin as an artificial hard tissue in wet conditions.

  4. Molecular Mechanics of Chitin-Protein Interface: Terminus and Side Chain

    CERN Document Server

    Yu, Zechuan

    2016-01-01

    Chitin and protein are two main building blocks for many natural biomaterials. The interaction between chitin and protein critically determines the properties of the composite biological materials. As living organisms usually encounter complex ambient conditions like water, pH and ions are critical factors towards the structural integrity of biomaterials. It is therefore essential to study the chitin-protein interface under different environmental conditions. Here, an atomistic model consisting of a chitin substrate and a protein filament is constructed, which is regarded as a representative of the chitin-protein interface existing in many chitin-based biomaterials. Based on this model, the mechanical properties of chitin-protein interface under different moisture and pH values are investigated through molecular dynamics simulations. The results reveal a weakening effect of water towards the chitin-protein interface, as well as acidity, i.e. the protonated protein forms a stronger adhesion to chitin than that...

  5. Extraction and Characterization of Chitin from the Beetle Holotrichia parallela Motschulsky

    Directory of Open Access Journals (Sweden)

    Feng Zhu

    2012-04-01

    Full Text Available Insect chitin was isolated from adult Holotrichia parallela by treatment with 1 M HCl and 1 M NaOH, following by 1% potassium permanganate solution for decolorization. The yield of chitin from this species is 15%. This insect chitin was compared with the commercial a-chitin from shrimp, by infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and elemental analysis. Both chitins exhibited similar chemical structures and physicochemical properties. Adult H. parallela is thus a promising alternative source of chitin.

  6. The chitin synthase genes chs-1 and chs-2 are essential for C. elegans development and responsible for chitin deposition in the eggshell and pharynx, respectively.

    Science.gov (United States)

    Zhang, Yinhua; Foster, Jeremy M; Nelson, Laura S; Ma, Dong; Carlow, Clotilde K S

    2005-09-15

    It is widely accepted that chitin is present in nematodes. However, its precise role in embryogenesis is unclear and it is unknown if chitin is necessary in other nematode tissues. Here, we determined the roles of chitin and the two predicted chitin synthase genes in Caenorhabditis elegans by chitin localization and gene disruption. Using a novel probe, we detected chitin in the eggshell and discovered elaborate chitin localization patterns in the pharyngeal lumen walls. Chitin deposition in these two sites is likely regulated by the activities of chs-1 (T25G3.2) and chs-2 (F48A11.1), respectively. Reducing chs-1 gene activity by RNAi led to eggs that were fragile and permeable to small molecules, and in the most severe case, absence of embryonic cell division. Complete loss of function in a chs-1 deletion resulted in embryos that lacked chitin in their eggshells and failed to divide. These results showed that eggshell chitin provides both mechanical support and chemical impermeability essential to developing embryos. Knocking down chs-2 by RNAi caused a defect in the pharynx and led to L1 larval arrest, indicating that chitin is involved in the development and function of the pharynx.

  7. Structural differences between chitin and chitosan extracted from three different marine sources.

    Science.gov (United States)

    Hajji, Sawssen; Younes, Islem; Ghorbel-Bellaaj, Olfa; Hajji, Rachid; Rinaudo, Marguerite; Nasri, Moncef; Jellouli, Kemel

    2014-04-01

    Three marine sources of chitin from Tunisia were investigated. Structural differences between α-chitin from shrimp (Penaeus kerathurus) waste, crab (Carcinus mediterraneus) shells, and β-chitin from cuttlefish (Sepia officinalis) bones were studied by the (13)C NMR, FTIR, and XRD diffractograms. The (13)C NMR analysis showed a splitting of the C3 and C5 carbon signals for α-chitin, while that of β-chitin was merged into a single resonance. The bands contour of deconvoluted and curve-fit FTIR spectra showed a more detailed structure of α-chitin in the region of O-H, N-H and CO stretching regions. IR and (13)C NMR were used to determine the chitin degree of acetylation (DA). XRD analysis indicated that α-chitins were more crystalline polymorph than β-chitin. Shrimp chitin was obtained with a good yield (20% on raw material dry weight) and no residual protein and salts. Chitosans, with a DA lower than 20% and relatively low molecular masses were prepared from the wet chitins in the same experimental conditions. They were perfectly soluble in acidic medium. Nevertheless, chitin and chitosan characteristics were depending upon the chitin source.

  8. Chitosan-sheath and chitin-core nanowhiskers.

    Science.gov (United States)

    Pereira, Antonio G B; Muniz, Edvani C; Hsieh, You-Lo

    2014-07-17

    Chitosan-sheath and α-chitin-core nanowhiskers (CsNWs) have been successfully generated by surface deacetylation of chitin nanowhiskers (CtNWs) in the never-dried state. Acid hydrolysis (3N HCl, 30 mL/g, 104°C) of pure chitin derived from crab shell yielded 65% 4-10nm thick, 16 nm wide and 214 nm long chitin whiskers (CtNWs) that were 86% crystalline and 81% acetylated. Surface deacetylation of CtNWs was robust in their never-dried state in 50% NaOH at a moderate 50°C for 6h, yielding 92% CsNWs. All deacetylated CsNWs retain the same α-chitin crystalline core at reduced 50% crystallinity and similar dimensions (4-12 nm thick, 15 nm wide, 247 long) as CtNWs, but reduced 60% acetylation reflecting the deacetylated surface layers. Progressive surface deacetylation was evident by the increased IP as well as increased positive charges under acidic pH and reduced negative charges at alkaline pH with increasing reaction time.

  9. Micro-CT Imaging of Denatured Chitin by Silver to Explore Honey Bee and Insect Pathologies

    OpenAIRE

    Butzloff, Peter R.

    2011-01-01

    BACKGROUND: Chitin and cuticle coatings are important to the environmental and immune defense of honey bees and insect pollinators. Pesticides or environmental effects may target the biochemistry of insect chitin and cuticle coating. Denaturing of chitin involves a combination of deacetylation, intercalation, oxidation, Schweiger-peeling, and the formation of amine hydrochloride salt. The term "denatured chitin" calls attention to structural and property changes to the internal membranes and ...

  10. The influence of selected ionic liquids on activity of chitin deacetylase

    Directory of Open Access Journals (Sweden)

    Aspras Izabela

    2016-03-01

    Full Text Available Chitin deacetylase is the only known enzyme which is able to deacetylate N-acetyl-D-glucosamine units in chitin or chitosan chains. As chitin can hardly be dissolved in organic/inorganic solvents, new solvents are still searched. Ionic liquids are promising for that application and for homophase enzymatic deacetylation. The aim of the work was to investigate the influence of selected ionic liquids on activity of chitin deacetylase.

  11. A Venom Gland Extracellular Chitin-Binding-Like Protein from Pupal Endoparasitoid Wasps, Pteromalus Puparum, Selectively Binds Chitin

    Directory of Open Access Journals (Sweden)

    Yu Zhu

    2015-11-01

    Full Text Available Chitin-binding proteins (CBPs are present in many species and they act in a variety of biological processes. We analyzed a Pteromalus puparum venom apparatus proteome and transcriptome and identified a partial gene encoding a possible CBP. Here, we report cloning a full-length cDNA of a sequence encoding a chitin-binding-like protein (PpCBP from P. puparum, a pupal endoparasitoid of Pieris rapae. The cDNA encoded a 96-amino-acid protein, including a secretory signal peptide and a chitin-binding peritrophin-A domain. Phylogenetic analysis of chitin binding domains (CBDs of cuticle proteins and peritrophic matrix proteins in selected insects revealed that the CBD of PpCBP clustered with the CBD of Nasonia vitripennis. The PpCBP is specifically expressed in the venom apparatus of P. puparum, mostly in the venom gland. PpCBP expression was highest at day one after adult eclosion and much lower for the following five days. We produced a recombinant PpCBP and binding assays showed the recombinant protein selectively binds chitin but not cellulose in vitro. We infer that PpCBP serves a structural role in the venom reservoir, or may be injected into the host to help wound healing of the host exoskeleton.

  12. Biosorption of gold from computer microprocessor leachate solutions using chitin.

    Science.gov (United States)

    Côrtes, Letícia N; Tanabe, Eduardo H; Bertuol, Daniel A; Dotto, Guilherme L

    2015-11-01

    The biosorption of gold from discarded computer microprocessor (DCM) leachate solutions was studied using chitin as a biosorbent. The DCM components were leached with thiourea solutions, and two procedures were tested for recovery of gold from the leachates: (1) biosorption and (2) precipitation followed by biosorption. For each procedure, the biosorption was evaluated considering kinetic, equilibrium, and thermodynamic aspects. The general order model was able to represent the kinetic behavior, and the equilibrium was well represented by the BET model. The maximum biosorption capacities were around 35 mg g(-1) for both procedures. The biosorption of gold on chitin was a spontaneous, favorable, and exothermic process. It was found that precipitation followed by biosorption resulted in the best gold recovery, because other species were removed from the leachate solution in the precipitation step. This method enabled about 80% of the gold to be recovered, using 20 g L(-1) of chitin at 298 K for 4 h.

  13. Effect of gamma radiation on chitin-nanosilver membranes

    International Nuclear Information System (INIS)

    Antimicrobial wound dressings are indispensable for the effective healing of skin wounds such as burns and ulcers. Various synthetic and natural polymers with good biocompatibility have been used to develop wound dressings. Chitin possesses excellent properties that are advantageous for wound dressing namely biocompatibility, biodegradability and haemostatic activity. Chitin-nanosilver membranes were developed for use as an antimicrobial dressing for wound care. For clinical applications, the wound dressing should be assuredly free of microbial contamination. Gamma irradiation has well appreciated technological advantages and is the most suitable method for the sterilization of biomedical materials. The present study was carried out to evaluate the effect of gamma radiation on the chemical and functional characteristics of the chitin-nanosilver membranes

  14. Blue Chitin columns for the extraction of heterocyclic amines from urine samples

    DEFF Research Database (Denmark)

    Bang, J.; Frandsen, Henrik Lauritz; Skog, K.

    2004-01-01

    . Blue Chitin columns were used for the extraction and purification of heterocyclic amines from urine samples spiked with 14 different heterocyclic amines. The samples were analysed using LC-MS. The results show that Blue Chitin columns provide a straightforward and rapid means of extracting heterocyclic...... amines from urine samples, and that Blue Chitin column are also useful in the purification of urinary metabolites....

  15. Chitin stimulates production of the antibiotic andrimid in a Vibrio corallilyticus strain

    DEFF Research Database (Denmark)

    Wietz, Matthias; Månsson, Maria; Gram, Lone

    2011-01-01

    per cell was twofold higher. In cultures with Artemia as live chitin model system, S2052 reached up to 108 cells ml-1, produced andrimid and showed attachment to the exoskeleton and chitinous exuviae. The metabolic focus on andrimid production with chitin indicates that the antibiotic could serve...

  16. Data for chitin binding activity of Moringa seed resistant protein (MSRP).

    Science.gov (United States)

    Sandanamudi, Anudeep; Bharadwaj, Kishan R; Cheruppanpullil, Radha

    2016-12-01

    Chitin binding activity of moringa seed resistant protein (MSRP) isolated from defatted moringa seed flour was investigated in the present study "Characterization of soluble dietary fiber from Moringa oleifera seeds and its immunomodulatory effects" (S. Anudeep, V.K. Prasanna, S.M. Adya, C. Radha, 2016) [1]. The assay reaction mixture contained 0.4 mg/ml of MSRP and different amounts (20-100 mg) of chitin. MSRP exhibited binding activity over wide range of chitin concentration. Maximum binding activity was observed at 80 mg of chitin. The property of MSRP to bind chitin can be exploited for its purification.

  17. Transmembrane myosin chitin synthase involved in mollusc shell formation produced in Dictyostelium is active

    Energy Technology Data Exchange (ETDEWEB)

    Schoenitzer, Veronika [INM - Leibniz Institute for New Materials, Biomineralisation Group, Campus D2.2, D-66123 Saarbruecken (Germany); Universitaet Regensburg, Biochemie I, Universitaetsstrasse 31, D-93053 Regensburg (Germany); Eichner, Norbert [Universitaet Regensburg, Biochemie I, Universitaetsstrasse 31, D-93053 Regensburg (Germany); Clausen-Schaumann, Hauke [Munich University of Applied Sciences, Lothstrasse 34, D-80335 Muenchen, Germany, and Center for NanoScience (CeNS), Geschwister-Scholl-Platz 1, D-80539 Muenchen (Germany); Weiss, Ingrid M., E-mail: ingrid.weiss@inm-gmbh.de [INM - Leibniz Institute for New Materials, Biomineralisation Group, Campus D2.2, D-66123 Saarbruecken (Germany); Universitaet Regensburg, Biochemie I, Universitaetsstrasse 31, D-93053 Regensburg (Germany)

    2011-12-02

    Highlights: Black-Right-Pointing-Pointer Dictyostelium produces the 264 kDa myosin chitin synthase of bivalve mollusc Atrina. Black-Right-Pointing-Pointer Chitin synthase activity releases chitin, partly associated with the cell surface. Black-Right-Pointing-Pointer Membrane extracts of transgenic slime molds produce radiolabeled chitin in vitro. Black-Right-Pointing-Pointer Chitin producing Dictyostelium cells can be characterized by atomic force microscopy. Black-Right-Pointing-Pointer This model system enables us to study initial processes of chitin biomineralization. -- Abstract: Several mollusc shells contain chitin, which is formed by a transmembrane myosin motor enzyme. This protein could be involved in sensing mechanical and structural changes of the forming, mineralizing extracellular matrix. Here we report the heterologous expression of the transmembrane myosin chitin synthase Ar-CS1 of the bivalve mollusc Atrina rigida (2286 amino acid residues, M.W. 264 kDa/monomer) in Dictyostelium discoideum, a model organism for myosin motor proteins. Confocal laser scanning immunofluorescence microscopy (CLSM), chitin binding GFP detection of chitin on cells and released to the cell culture medium, and a radiochemical activity assay of membrane extracts revealed expression and enzymatic activity of the mollusc chitin synthase in transgenic slime mold cells. First high-resolution atomic force microscopy (AFM) images of Ar-CS1 transformed cellulose synthase deficient D. discoideumdcsA{sup -} cell lines are shown.

  18. Chitin Nanofiber Transparent Paper for Flexible Green Electronics.

    Science.gov (United States)

    Jin, Jungho; Lee, Daewon; Im, Hyeon-Gyun; Han, Yun Cheol; Jeong, Eun Gyo; Rolandi, Marco; Choi, Kyung Cheol; Bae, Byeong-Soo

    2016-07-01

    A transparent paper made of chitin nanofibers (ChNF) is introduced and its utilization as a substrate for flexible organic light-emitting diodes is demonstrated. Given its promising macroscopic properties, biofriendly characteristics, and availability of the raw material, the utilization of the ChNF transparent paper as a structural platform for flexible green electronics is envisaged.

  19. Characterization of Chitin and Chitosan Molecular Structure in Aqueous Solution

    Energy Technology Data Exchange (ETDEWEB)

    Franca, Eduardo D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lins, Roberto D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Freitas, Luiz C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Straatsma, t. P. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2008-11-08

    Molecular dynamics simulations have been used to characterize the structure of chitin and chitosan fibers in aqueous solutions. Chitin fibers, whether isolated or in the form of a β-chitin nanoparticle, adopt the so-called 2-fold helix with Φ and φ values similar to its crystalline state. In solution, the intramolecular hydrogen bond HO3(n)•••O5(n+1) responsible for the 2-fold helical motif is stabilized by hydrogen bonds with water molecules in a well-defined orientation. On the other hand, chitosan can adopt five distinct helical motifs and its conformational equilibrium is highly dependent on pH. The hydrogen bond pattern and solvation around the O3 atom of insoluble chitosan (basic pH) are nearly identical to these quantities in chitin. Our findings suggest that the solubility and conformation of these polysaccharides are related to the stability of the intrachain HO3(n)•••O5(n+1) hydrogen bond, which is affect by the water exchange around the O3-HO3 hydroxyl group.

  20. Chitin purification from shrimp wastes by microbial deproteination and decalcification.

    Science.gov (United States)

    Xu, Y; Gallert, C; Winter, J

    2008-06-01

    Chitin was purified from Penaeus monodon and Crangon crangon shells using a two-stage fermentation process with anaerobic deproteination followed by decalcification through homofermentative lactic acid fermentation. Deproteinating enrichment cultures from sewage sludge and ground meat (GM) were used with a proteolytic activity of 59 and 61 mg N l(-1) h(-1) with dried and 26 and 35 mg N l(-1) h(-1) with wet P. monodon shells. With 100 g wet cells of proteolytic bacteria per liter, protein removal was obtained in 42 h. An anaerobic spore-forming bacterium HP1 was isolated from enrichment GM. Its proteolytic activity was 76 U ml(-1) compared to 44 U ml(-1) of the consortium. Glucose was fermented with Lactobacillus casei MRS1 to lactic acid. At a pH of 3.6, calcium carbonate of the shells was solubilised. After deproteination and decalcification of P. monodon or C. crangon shells, the protein content was 5.8% or 6.7%, and the calcium content was 0.3% or 0.4%, respectively. The viscosity of the chitin from P. monodon and C. crangon was 45 and 135 mPa s, respectively, whereas purchased crab shell chitin (practical grade) had a viscosity of 21 mPa s, indicating a higher quality of biologically purified chitin. PMID:18418590

  1. La production de chitine par les crustacés dans les écosystèmes marins

    OpenAIRE

    Jeuniaux, Charles; Voss-Foucart, Marie-Françoise; Bussers, Jean-Claude

    1993-01-01

    Chitin is synthesized by numerous animal species, either unicellular organisms or metazoans, belonging mainly to zoological groups of the Coelomate Spiralia lineage. However, the produced chitin in marine ecosystems is principally by crustaceans. A comparative study of analytical data so far available allowed calculation of chitin biomass and chitin production values in some types of marine ecosystems, and thus estimation of the quantitative importance of chitin in the biogeochemical cycles o...

  2. Microbial deproteinization of shrimp shell penaeus merguiensis for chitin extraction

    Directory of Open Access Journals (Sweden)

    Fatemeh Sedaghat

    2016-09-01

    Full Text Available Introduction: After cellulose, Chitin is the most abundant biopolymer in nature. The most important derivative of chitin is chitosan, obtained by deacetylation of chitin. Major sources of chitin are the exoskeleton of marine crustaceans such as crab, shrimp, and krill. Chitin extraction from shrimp shells can be carried out chemically or using biological methods. Microbial fermentation as an eco-friendly procedure is a suitable alternative for the chemical and enzymatic processes. In this study, the effect of three protease-producing bacteria species (Pseudomonas aeruginosa, Serratia marcescens, and Bacillus pumilus on the efficiency of microbial demineralization (DM and deproteinization (DP of the shrimp shell penaeus merguiensis, was investigated. Furthermore, the antioxidant activity of hydrolysate obtained during the fermentation process was measured. Materials and methods: Demineralization and deproteinization was carried out by incubating shrimp waste inoculated with bacteria at 30°C and 100 rpm for 6 days. Results: Statistical analysis of data showed a significant difference between the percentage of demineralization and deproteinization in different bacteria species (p<0.05. The highest deproteinization (74.76% and demineralization rate (78.46% were obtained with P. aeruginosa, while the lowest was observed for S. marcescens. Antioxidant activity of hydrolysate also showed a significant difference. The highest reducing power and total antioxidant capacity were observed in volumes of 400 µl hydrolysate of S.marcescens and 100 µl hydrolysate of B. pumilus, respectively. Discussion and conclusion: The results indicated that P. aeruginosa in comparison with other bacterial strains, had a higher ability to remove proteins and minerals from shrimp shell waste. Therefore, the use of this bacterium is suitable for protein and minerals removal from marine crustaceans.

  3. CSD2, CSD3, and CSD4, genes required for chitin synthesis in Saccharomyces cerevisiae: the CSD2 gene product is related to chitin synthases and to developmentally regulated proteins in Rhizobium species and Xenopus laevis.

    OpenAIRE

    Bulawa, C E

    1992-01-01

    In Saccharomyces cerevisiae, chitin forms the primary division septum and the bud scar in the walls of vegetative cells. Three chitin synthetic activities have been detected. Two of them, chitin synthase I and chitin synthase II, are not required for synthesis of most of the chitin present in vivo. Using a novel screen, I have identified three mutations, designated csd2, csd3, and csd4, that reduce levels of chitin in vivo by as much as 10-fold without causing any obvious perturbation of cell...

  4. Poriferan Chitin as a Versatile Template for Extreme Biomimetics

    Directory of Open Access Journals (Sweden)

    Marcin Wysokowski

    2015-02-01

    Full Text Available In this mini-review, we shall first cover a short history of the discovery of chitin isolated from sponges; as well as its evolutionarily ancient roots. Next, we will delve into the unique structural, mechanical, and thermal properties of this naturally occurring polymer to illuminate how its physicochemical properties may find uses in diverse areas of the material sciences. We show how the unique properties and morphology of sponge chitin renders it quite useful for the new route of “Extreme Biomimetics”; where high temperatures and pressures allow a range of interesting bioinorganic composite materials to be made. These new biomaterials have electrical, chemical, and material properties that have applications in water filtration, medicine, catalysis, and biosensing.

  5. Removal of Petroleum Spill in Water by Chitin and Chitosan

    Directory of Open Access Journals (Sweden)

    Francisco Cláudio de Freitas Barros

    2014-05-01

    Full Text Available The present study was undertaken to evaluate the capacity of adsorption of crude oil spilled in seawater by chitin flakes, chitin powder, chitosan flakes, chitosan powder, and chitosan solution. The results showed that, although chitosan flakes had a better adsorption capacity by oil (0.379 ± 0.030 grams oil per gram of adsorbent, the biopolymer was sinking after adsorbing oil. Chitosan solution did not present such inconvenience, despite its lower adsorption capacity (0.013 ± 0.001 grams oil per gram of adsorbent. It was able to form a polymeric film on the oil slick, which allowed to restrain and to remove the oil from the samples of sea water. The study also suggests that chitosan solution 0.5% has greater efficiency against oil spills in alkaline medium than acidic medium.

  6. Chitin and carbon nanotube composites as biocompatible scaffolds for neuron growth

    Science.gov (United States)

    Singh, Nandita; Chen, Jinhu; Koziol, Krzysztof K.; Hallam, Keith R.; Janas, Dawid; Patil, Avinash J.; Strachan, Ally; G. Hanley, Jonathan; Rahatekar, Sameer S.

    2016-04-01

    The design of biocompatible implants for neuron repair/regeneration ideally requires high cell adhesion as well as good electrical conductivity. Here, we have shown that plasma-treated chitin carbon nanotube composite scaffolds show very good neuron adhesion as well as support of synaptic function of neurons. The addition of carbon nanotubes to a chitin biopolymer improved the electrical conductivity and the assisted oxygen plasma treatment introduced more oxygen species onto the chitin nanotube scaffold surface. Neuron viability experiments showed excellent neuron attachment onto plasma-treated chitin nanotube composite scaffolds. The support of synaptic function was evident on chitin/nanotube composites, as confirmed by PSD-95 staining. The biocompatible and electrically-conducting chitin nanotube composite scaffold prepared in this study can be used for in vitro tissue engineering of neurons and, potentially, as an implantable electrode for stimulation and repair of neurons.

  7. Graft polymerization of acrylic acid onto chitin nanofiber to improve dispersibility in basic water.

    Science.gov (United States)

    Ifuku, Shinsuke; Iwasaki, Masayoshi; Morimoto, Minoru; Saimoto, Hiroyuki

    2012-09-01

    Graft copolymerization of acrylic acid (AA) on chitin nanofibers was carried out with potassium persulfate as a free radical initiator in an aqueous medium. The molar ratio of grafted AA increased with the AA concentration. The grafted chitin nanofibers were characterized by FT-IR, FE-SEM, UV-vis, XRD, and TGA. After polymerization, the characteristic morphology of chitin nanofibers was maintained. Chitin nanofibers grafted with AA were efficiently dissociated and dispersed homogeneously in basic water because of the electrostatic repulsion effect between nanofibers. AA was grafted on the surface and amorphous part of chitin nanofibers, and the original crystalline structure of α-chitin was maintained. At 330 °C, the weight residue of the graft copolymer increased with the grafted AA content. PMID:24751085

  8. Customizing Properties of β-Chitin in Squid Pen (Gladius by Chemical Treatments

    Directory of Open Access Journals (Sweden)

    Alessandro Ianiro

    2014-12-01

    Full Text Available The squid pen (gladius from the Loligo vulgaris was used for preparation of β-chitin materials characterized by different chemical, micro- and nano-structural properties that preserved, almost completely the macrostructural and the mechanical ones. The β-chitin materials obtained by alkaline treatment showed porosity, wettability and swelling that are a function of the duration of the treatment. Microscopic, spectroscopic and synchrotron X-ray diffraction techniques showed that the chemical environment of the N-acetyl groups of the β-chitin chains changes after the thermal alkaline treatment. As a consequence, the crystalline packing of the β-chitin is modified, due to the intercalation of water molecules between β-chitin sheets. Potential applications of these β-chitin materials range from the nanotechnology to the regenerative medicine. The use of gladii, which are waste products of the fishing industry, has also important environmental implications.

  9. Self-bonded composite films based on cellulose nanofibers and chitin nanocrystals as antifungal materials.

    Science.gov (United States)

    Robles, Eduardo; Salaberria, Asier M; Herrera, Rene; Fernandes, Susana C M; Labidi, Jalel

    2016-06-25

    Cellulose nanofibers and chitin nanocrystals, two main components of agricultural and aquacultural by-products, were obtained from blue agave and yellow squat lobster industrial residues. Cellulose nanofibers were obtained using high pressure homogenization, while chitin nanocrystals were obtained by hydrolysis in acid medium. Cellulose nanofibers and chitin nanocrystals were characterized by X-ray diffraction, Atomic Force Microscopy and Infrared spectroscopy. Self-bonded composite films with different composition were fabricated by hot pressing and their properties were evaluated. Antifungal activity of chitin nanocrystals was studied using a Cellometer(®) cell count device, mechanical properties at tension were measured with a universal testing machine, water vapor permeability was evaluated with a thermohygrometer and surface tension with sessile drop contact angle method. The addition of chitin nanocrystals reduced slightly the mechanical properties of the composite. Presence of chitin nanocrystals influenced the growth of Aspergillus sp fungus in the surface of the composites as expected. PMID:27083791

  10. Surface morphology of chitin highly related with the isolated body part of butterfly (Argynnis pandora).

    Science.gov (United States)

    Kaya, Murat; Bitim, Betül; Mujtaba, Muhammad; Koyuncu, Turgay

    2015-11-01

    This study was conducted to understand the differences in the physicochemical properties of chitin samples isolated from the wings and the other body parts except the wings (OBP) of a butterfly species (Argynnis pandora). The same isolation method was used for obtaining chitin specimens from both types of body parts. The chitin content of the wings (22%) was recorded as being much higher than the OBP (8%). The extracted chitin samples were characterized via FT-IR, TGA, XRD, SEM, and elemental analysis techniques. Results of these characterizations revealed that the chitins from both structures (wings and OBP) were very similar, except for their surface morphologies. SEM results demonstrated one type of surface morphology for the wings and four different surface morphologies for the OBP. Therefore, it can be hypothesized that the surface morphology of the chitin is highly related with the body part.

  11. Effect of Acetyl Group on Mechanical Properties of Chitin/Chitosan Nanocrystal: A Molecular Dynamics Study

    Directory of Open Access Journals (Sweden)

    Junhe Cui

    2016-01-01

    Full Text Available Chitin fiber is the load-bearing component in natural chitin-based materials. In these materials, chitin is always partially deacetylated to different levels, leading to diverse material properties. In order to understand how the acetyl group enhances the fracture resistance capability of chitin fiber, we constructed atomistic models of chitin with varied acetylation degree and analyzed the hydrogen bonding pattern, fracture, and stress-strain behavior of these models. We notice that the acetyl group can contribute to the formation of hydrogen bonds that can stabilize the crystalline structure. In addition, it is found that the specimen with a higher acetylation degree presents a greater resistance against fracture. This study describes the role of the functional group, acetyl groups, in crystalline chitin. Such information could provide preliminary understanding of nanomaterials when similar functional groups are encountered.

  12. Chitin dipentanoate as the new technologically usable biomaterial.

    Science.gov (United States)

    Skołucka-Szary, Karolina; Ramięga, Aleksandra; Piaskowska, Wanda; Janicki, Bartosz; Grala, Magdalena; Rieske, Piotr; Stoczyńska-Fidelus, Ewelina; Piaskowski, Sylwester

    2015-10-01

    In this article, the synthesis of novel biopolymer, chitin dipentanoate (Di-O-Valeryl Chitin, DVCH) has been described. DVCH is a chitin derivative esterified with two valeryl groups at positions 3 and 6 of the N-acetylglucosamine units and it is soluble in common organic solvents like ethanol, methanol, acetone, dichloromethane, 1,2-dichloroethane, N,N-dimethylmethanamide, N,N-dimethylacetamide and ethyl acetate. Highly efficient synthesis (degree of esterification close to 2) of DVCH was achieved by employing a huge excess of valeric anhydride used as both the acylation agent and the reaction medium in the presence of perchloric acid as catalyst. Studies on the DVCH synthesis were aimed at finding optimal conditions (temperature, reaction time) to obtain DVCH with high reaction yield and desirable physicochemical properties. Biological data demonstrate that DVCH is non-cytotoxic in vitro and doesn't exert irritating or allergic effects to animal skin. Thanks to its filmogenic properties, it can be used to manufacture threads, foils, foams and non-woven materials. Moreover, DVCH can be easily processed by salt-leaching method to prepare highly porous structures exhibiting open-cell architecture, that can be further employed in wound dressing therapies and scaffolds for tissue engineering. PMID:26117738

  13. Chitin synthetase in encysting Giardia lamblia and Entamoeba invadens

    International Nuclear Information System (INIS)

    Giardia lamblia (Gl) and Entamoeba invadens (Ei) are protozoan parasites with two morphologic stages in their life cycles. Motile trophozoites colonize the intestine of humans and reptiles respectively. Water resistant cysts, which can survive outside the host, transmit infection. In vitro cyst formation of Ei from trophozoites has been reported, and the authors have recently induced in vitro encystation of Gl. Although the cyst walls of both parasites contain chitin, it synthesis by encysting trophozoites has not been reported. The authors now show that encystation conditions greatly increase chitin synthetase (CS) specific activity (incorporation of 3H GlcNAc from UDP-GlcNAc into TCA-or alcohol-precipitable material). Extracts of encysting Gl incorporated 3.6 nmol/mg protein in 5 hr compared to < 0.005 in controls. Extracts of encysting Fi incorporated 4.8 n mol/mg protein, compared to 1.7 in the control. CS activity of both parasites requires preformed chitin. The Gl enzyme requires a reducing agent, is inhibited by digitonin and the CS inhibitors, polyoxin D and Nikkomycin, but not by tunicamycin. The product is digested by chitinase. Ei enzyme does not require a reducing agent and is stimulated by 1 mg/ml digitonin, but inhibited by higher concentrations. These studies demonstrate CS enzymes which may play important roles in encystation of Gl and Ei

  14. Chitin synthetase in encysting Giardia lamblia and Entamoeba invadens

    Energy Technology Data Exchange (ETDEWEB)

    Das, S.; Gillin, F.D.

    1987-05-01

    Giardia lamblia (Gl) and Entamoeba invadens (Ei) are protozoan parasites with two morphologic stages in their life cycles. Motile trophozoites colonize the intestine of humans and reptiles respectively. Water resistant cysts, which can survive outside the host, transmit infection. In vitro cyst formation of Ei from trophozoites has been reported, and the authors have recently induced in vitro encystation of Gl. Although the cyst walls of both parasites contain chitin, it synthesis by encysting trophozoites has not been reported. The authors now show that encystation conditions greatly increase chitin synthetase (CS) specific activity (incorporation of /sup 3/H GlcNAc from UDP-GlcNAc into TCA-or alcohol-precipitable material). Extracts of encysting Gl incorporated 3.6 nmol/mg protein in 5 hr compared to < 0.005 in controls. Extracts of encysting Fi incorporated 4.8 n mol/mg protein, compared to 1.7 in the control. CS activity of both parasites requires preformed chitin. The Gl enzyme requires a reducing agent, is inhibited by digitonin and the CS inhibitors, polyoxin D and Nikkomycin, but not by tunicamycin. The product is digested by chitinase. Ei enzyme does not require a reducing agent and is stimulated by 1 mg/ml digitonin, but inhibited by higher concentrations. These studies demonstrate CS enzymes which may play important roles in encystation of Gl and Ei.

  15. Structure and Function of Chitosan (V). Conformations of Ethylene Glycol Derivatives of Chitin and Chitosan

    OpenAIRE

    YUI, Toshifumi; NAKATA, Kunihiko; OGAWA, Kozo

    1996-01-01

    Molecular structures of ethylene glycol derivatives of chitin and chitosan, where 0-6 of chitin chain was etherified and both 0-3 and 0-6 of chitosan were substituted, were studied by X-ray fiber diffraction methods coupled with conformational analyses. The extended two-fold helical conformations of both chitin and chitosan chains were retained even by the etherifications. Possible molecular conformations of these derivatives were proposed.

  16. Chitin, Chitosan, and Its Derivatives for Wound Healing: Old and New Materials

    OpenAIRE

    Kazuo Azuma; Ryotaro Izumi; Tomohiro Osaki; Shinsuke Ifuku; Minoru Morimoto; Hiroyuki Saimoto; Saburo Minami; Yoshiharu Okamoto

    2015-01-01

    Chitin (β-(1-4)-poly-N-acetyl-D-glucosamine) is widely distributed in nature and is the second most abundant polysaccharide after cellulose. It is often converted to its more deacetylated derivative, chitosan. Previously, many reports have indicated the accelerating effects of chitin, chitosan, and its derivatives on wound healing. More recently, chemically modified or nano-fibrous chitin and chitosan have been developed, and their effects on wound healing have been evaluated. In this review,...

  17. A transcriptional regulator linking quorum sensing and chitin induction to render Vibrio cholerae naturally transformable

    OpenAIRE

    Lo Scrudato, Mirella; Blokesch, Melanie

    2013-01-01

    The human pathogen Vibrio cholerae is an aquatic bacterium associated with zooplankton and their chitinous exoskeletons. On chitinous surfaces, V. cholerae initiates a developmental programme, known as natural competence, to mediate transformation, which is a mode of horizontal gene transfer. Competence facilitates the uptake of free DNA and recombination into the bacterial genome. Recent studies have indicated that chitin surfaces are required, but not sufficient to induce competence. Two ad...

  18. Nanostructured biocomposite films of high toughness based on native chitin nanofibers and chitosan

    Science.gov (United States)

    Mushi, Ngesa; Utsel, Simon; Berglund, Lars

    2014-11-01

    Chitosan is widely used in films for packaging applications. Chitosan reinforcement by stiff particles or fibers is usually obtained at the expense of lowered ductility and toughness. Here, chitosan film reinforcement by a new type of native chitin nanofibers is reported. Films are prepared by casting from colloidal suspensions of chitin in dissolved chitosan. The nanocomposite films are chitin nanofiber networks in chitosan matrix. Characterization is carried out by dynamic light scattering, quartz crystal microbalance, field emission scanning electron microscopy, tensile tests and dynamic mechanical analysis. The nanostructured biocomposite was produced in volume fractions of 0, 8, 22 and 56% chitin nanofibers. Favorable chitin-chitosan synergy for colloidal dispersion is demonstrated. Also, lowered moisture sorption is observed for the composites, probably due to the favorable chitin-chitosan interface. The highest toughness (area under stress-strain curve) was observed at 8 vol% chitin content. The toughening mechanisms and the need for well-dispersed chitin nanofibers is discussed. Finally, desired structural characteristics of ductile chitin biocomposites are discussed.

  19. Nanostructured biocomposite films of high toughness based on native chitin nanofibers and chitosan

    Directory of Open Access Journals (Sweden)

    Ngesa Ezekiel Mushi

    2014-11-01

    Full Text Available Chitosan is widely used in films for packaging applications. Chitosan reinforcement by stiff particles or fibers is usually obtained at the expense of lowered ductility and toughness. Here, chitosan film reinforcement by a new type of native chitin nanofibers is reported. Films are prepared by casting from colloidal suspensions of chitin in dissolved chitosan. The nanocomposite films are chitin nanofiber networks in chitosan matrix. Characterization is carried out by dynamic light scattering, quartz crystal microbalance, field emission scanning electron microscopy, tensile tests and dynamic mechanical analysis. The nanostructured biocomposite was produced in volume fractions of 0, 8, 22 and 56% chitin nanofibers. Favorable chitin-chitosan synergy for colloidal dispersion is demonstrated. Also, lowered moisture sorption is observed for the composites, probably due to the favorable chitin-chitosan interface. The highest toughness (area under stress-strain curve was observed at 8 vol% chitin content. The toughening mechanisms and the need for well-dispersed chitin nanofibers is discussed. Finally, desired structural characteristics of ductile chitin biocomposites are discussed.

  20. A comparative study of sorption of chromium (III) onto chitin and chitosan

    Science.gov (United States)

    Singh, Pooja; Nagendran, R.

    2016-06-01

    Heavy metals have always been the most hazardous components in the wastewater of industries like electroplating, automobiles, mining facilities and fertilizer manufacturers. Treatment of heavy metal laden wastewater requires expensive operational and maintenance systems. Food processing industries create a huge amount of shell waste which is sold to poultry farms in powdered form but the quantity thus used is still not comparable to the left over waste. The shell contains chitin which acts as an adsorbent for the heavy metals and can be used to treat heavy metal wastewater. The paper presents a study on the use of chitin and its processed product, chitosan, to remove chromium. Shake flask experiment was conducted to compare the adsorptive capacity of chitin and chitosan for chromium removal from simulated solution and isotherm studies were carried out. The studies showed that the chitosan was a better adsorbent than chitin. Both chitin and chitosan gave best adsorption results at pH 3. Chitin exhibited maximum chromium removal of 49.98 % in 20 min, whereas chitosan showed 50 % removal efficiency at a contact time of 20 min showing higher adsorptive capacity for chromium than chitin. The Langmiur and Freundlich isotherm studies showed very good adsorption capacity and monolayer interaction according to the regression coefficient 0.973 for chitosan and 0.915 for chitin. The regression coefficient for Freundlich isotherm was 0.894 and 0.831 for chitosan and chitin, respectively.

  1. Comparison of Extraction Methods of Chitin from Ganoderma lucidum Mushroom Obtained in Submerged Culture

    Directory of Open Access Journals (Sweden)

    Sandra Patricia Ospina Álvarez

    2014-01-01

    Full Text Available The chitin was isolated from the Ganoderma lucidum submerged cultures mycelium as potential source of chitin under biotechnological processes. The extraction of chitin was carried out through 5 different assays which involved mainly three phases: pulverization of the mushroom, deproteinization of the mycelia with NaOH solution, and a process of decolorization with potassium permanganate and oxalic acid. The chitin contents extracted from 9-day mycelia were 413, 339, 87, 78, and 144 mg/g−1 (milligrams of chitin/grams of dry biomass for A1, A2, A3, A4, and A5, respectively. Obtained chitin was characterized by X-Ray Diffraction (XRD, by Fourier transform infrared spectroscopy (FTIR, and by thermal analysis (TGA. The results showed that Ganoderma lucidum chitin has similar characteristic of chitin from different fonts. The advantage of the biotechnological processes and the fact that Ganoderma lucidum fungus may be used as a potential raw material for chitin production were demonstrated.

  2. Recent trends in biological extraction of chitin from marine shell wastes: a review.

    Science.gov (United States)

    Kaur, Surinder; Dhillon, Gurpreet Singh

    2015-03-01

    The natural biopolymer chitin and its deacetylated product chitosan are widely used in innumerable applications ranging from biomedicine, pharmaceuticals, food, agriculture and personal care products to environmental sector. The abundant and renewable marine processing wastes are commercially exploited for the extraction of chitin. However, the traditional chitin extraction processes employ harsh chemicals at elevated temperatures for a prolonged time which can harm its physico-chemical properties and are also held responsible for the deterioration of environmental health. In view of this, green extraction methods are increasingly gaining popularity due to their environmentally friendly nature. The bioextraction of chitin from crustacean shell wastes has been increasingly researched at the laboratory scale. However, the bioextraction of chitin is not currently exploited to its maximum potential on the commercial level. Bioextraction of chitin is emerging as a green, cleaner, eco-friendly and economical process. Specifically in the chitin extraction, microorganisms-mediated fermentation processes are highly desirable due to easy handling, simplicity, rapidity, controllability through optimization of process parameters, ambient temperature and negligible solvent consumption, thus reducing environmental impact and costs. Although, chitin production from crustacean shell waste through biological means is still at its early stage of development, it is undergoing rapid progress in recent years and showing a promising prospect. Driven by reduced energy, wastewater or solvent, advances in biological extraction of chitin along with valuable by-products will have high economic and environmental impact.

  3. EUCHIS '99 : proceedings of the 3rd international conference of the European Chitin Society, Potsdam, Germany, Aug. 31 - Sept. 3, 1999

    OpenAIRE

    2010-01-01

    Contents: Production and Applications of Chitin and Chitosan Krill as a promising raw material for the production of chitin in Europe - Containerized plant for producing chitin - Preparation and characterization of chitosan from Mucorales - Chitosan from Absidia orchidis - Scaling up of lactic acid fermentation of prawn wastes in packed-bed column reactor for chitin recovery - Preparation of chitin by acetic acid fermentation - Inter-source reproducibility of the chitin deacetylation process ...

  4. SEM characterization of anatomical variation in chitin organization in insect and arthropod cuticles.

    Science.gov (United States)

    Chandran, Rakkiyappan; Williams, Lee; Hung, Albert; Nowlin, Kyle; LaJeunesse, Dennis

    2016-03-01

    The cuticles of insects and arthropods have some of the most diverse material properties observed in nature, so much so that it is difficult to imagine that all cutciles are primarily composed of the same two materials: a fibrous chitin network and a matrix composed of cuticle proteins. Various factors contribute to the mechanical and optical properties of an insect or arthropod cuticle including the thickness and composition. In this paper, we also identified another factor that may contribute to the optical, surface, and mechanical properties of a cuticle, i.e. the organization of chitin nanofibers and chitin fiber bundles. Self-assembled chitin nanofibers serve as the foundation for all higher order chitin structures in the cuticles of insects and other arthropods via interactions with structural cuticle proteins. Using a technique that enables the characterization of chitin organization in the cuticle of intact insects and arthropod exoskeletons, we demonstrate a structure/function correlation of chitin organization with larger scale anatomical structures. The chitin scaffolds in cuticles display an extraordinarily diverse set of morphologies that may reflect specific mechanical or physical properties. After removal of the proteinaceous and mineral matrix of a cuticle, we observe using SEM diverse nanoscale and micro scale organization of in-situ chitin in the wing, head, eye, leg, and dorsal and ventral thoracic regions of the periodical cicada Magicicada septendecim and in other insects and arthropods. The organization of chitin also appears to have a significant role in the organization of nanoscale surface structures. While microscale bristles and hairs have long been known to be chitin based materials formed as cellular extensions, we have found a nanostructured layer of chitin in the cuticle of the wing of the dog day annual cicada Tibicen tibicens, which may be the scaffold for the nanocone arrays found on the wing. We also use this process to examine

  5. SEM characterization of anatomical variation in chitin organization in insect and arthropod cuticles.

    Science.gov (United States)

    Chandran, Rakkiyappan; Williams, Lee; Hung, Albert; Nowlin, Kyle; LaJeunesse, Dennis

    2016-03-01

    The cuticles of insects and arthropods have some of the most diverse material properties observed in nature, so much so that it is difficult to imagine that all cutciles are primarily composed of the same two materials: a fibrous chitin network and a matrix composed of cuticle proteins. Various factors contribute to the mechanical and optical properties of an insect or arthropod cuticle including the thickness and composition. In this paper, we also identified another factor that may contribute to the optical, surface, and mechanical properties of a cuticle, i.e. the organization of chitin nanofibers and chitin fiber bundles. Self-assembled chitin nanofibers serve as the foundation for all higher order chitin structures in the cuticles of insects and other arthropods via interactions with structural cuticle proteins. Using a technique that enables the characterization of chitin organization in the cuticle of intact insects and arthropod exoskeletons, we demonstrate a structure/function correlation of chitin organization with larger scale anatomical structures. The chitin scaffolds in cuticles display an extraordinarily diverse set of morphologies that may reflect specific mechanical or physical properties. After removal of the proteinaceous and mineral matrix of a cuticle, we observe using SEM diverse nanoscale and micro scale organization of in-situ chitin in the wing, head, eye, leg, and dorsal and ventral thoracic regions of the periodical cicada Magicicada septendecim and in other insects and arthropods. The organization of chitin also appears to have a significant role in the organization of nanoscale surface structures. While microscale bristles and hairs have long been known to be chitin based materials formed as cellular extensions, we have found a nanostructured layer of chitin in the cuticle of the wing of the dog day annual cicada Tibicen tibicens, which may be the scaffold for the nanocone arrays found on the wing. We also use this process to examine

  6. The effects of chitosan and chitin wound dressings in hairless dogs

    Directory of Open Access Journals (Sweden)

    Tohru Kimura

    2011-11-01

    Full Text Available The effects on wound healing of chitosan and chitin wound dressings were clinically andhistopathologically investigated using a split thickness wound in hairless dogs. Wound dressings used inthis study included examined were dried porcine skin (DP skin, cotton type chitosan (CT chitosan andchitin fiber dressing (chitin FD. Clinically, there were no differences in wound healing among the sitestreated with chitosan, chitin and the untreated control sites. In contrast, DP skin and CT chitosan did notpromote wound healing. CT chitosan dressings induced severe inflammatory reactions. In the sitestreated with chitin FD, wound healing was delayed. Histopathologically, there were few differences inreepithelialization among the sites treated with chitosan, chitin and the WD-untreated sites. The sitestreated with DP skin received elastic fibers from DP skin. CT chitosan dressings had a deleterious effecton wound healing (reepithelialization and granulation. Dyskeratosis, congestion, hemorrhage, cellularinfiltration, intra- and intercellular edema were seen in the epidermis. Bleeding, infiltration ofinflammatory cells and mast cells, and edematous changes were seen in the dermis. In the sites treatedwith chitin FD, the invasion of mononuclear cells, mast cells and erythrocytes caused the retardeddevelopment of reepithelialization. It was concluded that chitosan and chitin had few deleterious effectson wound healing whereas DP skin, CT chitosan and chitin FD induced inflammation in the wound ofhairless dogs. In addition, it was clear that there are species differences in the skin reactions to wounddressings. These results suggested special care should be taken in veterinary clinical use of humanmedical wound dressings.

  7. Beneficial effect of gamma irradiation on the N-deacetylation of chitin to form chitosan

    Science.gov (United States)

    Tahtat, Djamel; Uzun, Cengiz; Mahlous, Mohamed; Güven, Olgun

    2007-12-01

    The effect of gamma irradiation on the N-deacetylation of chitin to form chitosan was studied. Chitin from crab shells was irradiated up to 20 kGy and N-deacetylated in aqueous NaOH solution (40% and 60% w/w) at 60 and 100 °C for 60 min. The degree of N-deacetylation (DD) of non-irradiated and irradiated samples was determined by IR-band ratio method. It was found that higher extent of N-deacetylation was achieved for the chitin samples irradiated up to 20 kGy doses as compared to non-irradiated chitin. The DD values of chitin, prepared from non-irradiated and 20 kGy irradiated chitins by N-deacetylation at 60 °C with 40% NaOH for 60 min, were found to be 38% and 60%, respectively. The increase in DD by irradiation was interpreted as a result of reduction in molecular weight of chitin. Low dose irradiation of chitin has provided the possibility of its N-deacetylation into chitosan at much milder reaction conditions.

  8. Beneficial effect of gamma irradiation on the N-deacetylation of chitin to form chitosan

    Energy Technology Data Exchange (ETDEWEB)

    Tahtat, Djamel [Algiers Nuclear Research Center, 2 Bd, Frantz Fanon BP 399 Alger-Gare, Algiers (Algeria); Uzun, Cengiz [Hacettepe University, Department of Chemistry, Beytepe, 06532 Ankara (Turkey)], E-mail: uzun@hacettepe.edu.tr; Mahlous, Mohamed [Algiers Nuclear Research Center, 2 Bd, Frantz Fanon BP 399 Alger-Gare, Algiers (Algeria); Gueven, Olgun [Hacettepe University, Department of Chemistry, Beytepe, 06532 Ankara (Turkey)

    2007-12-15

    The effect of gamma irradiation on the N-deacetylation of chitin to form chitosan was studied. Chitin from crab shells was irradiated up to 20 kGy and N-deacetylated in aqueous NaOH solution (40% and 60% w/w) at 60 and 100 deg. C for 60 min. The degree of N-deacetylation (DD) of non-irradiated and irradiated samples was determined by IR-band ratio method. It was found that higher extent of N-deacetylation was achieved for the chitin samples irradiated up to 20 kGy doses as compared to non-irradiated chitin. The DD values of chitin, prepared from non-irradiated and 20 kGy irradiated chitins by N-deacetylation at 60 deg. C with 40% NaOH for 60 min, were found to be 38% and 60%, respectively. The increase in DD by irradiation was interpreted as a result of reduction in molecular weight of chitin. Low dose irradiation of chitin has provided the possibility of its N-deacetylation into chitosan at much milder reaction conditions.

  9. Metabolic engineering of the morphology of Aspergillus oryzae by altering chitin synthesis

    DEFF Research Database (Denmark)

    Muller, C.; Mcintyre, Mhairi; Hansen, Kim;

    2002-01-01

    Morphology and alpha-amylase production during submerged cultivation were examined in a wild-type strain (A1560) and in strains of Aspergillus oryzae in which chitin synthase B (chsB) and chitin synthesis myosin A (csmA) have been disrupted (ChsB/G and CM101). In a flowthrough cell, the growth of...

  10. Bacterial communities in chitin-amended soil as revealed by 16S rRNA gene based pyrosequencing

    NARCIS (Netherlands)

    Cretoiu, Mariana Silvia; Kielak, Anna Maria; Schluter, Andreas; van Elsas, Jan Dirk

    2014-01-01

    Chitin and its derivatives are natural biopolymers that are often used as compounds for the control of soilborne plant pathogens. In spite of recent advances in agricultural practices involving chitin amendments, the microbial communities in chitin-amended soils remain poorly known. The objectives o

  11. Physiological and morphological aspects of Aedes aegypti developing larvae: effects of the chitin synthesis inhibitor novaluron.

    Directory of Open Access Journals (Sweden)

    Luana C Farnesi

    Full Text Available Population control of the dengue vector mosquito, Aedes aegypti, is difficult due to many reasons, one being the development of resistance to neurotoxic insecticides employed. The biosynthesis of chitin, a major constituent of insect cuticle, is a novel target for population control. Novaluron is a benzoylphenylurea (BPU that acts as a chitin synthesis inhibitor, already used against mosquitoes. However, information regarding BPU effects on immature mosquito stages and physiological parameters related with mosquito larval development are scarce. A set of physiological parameters were recorded in control developing larvae and novaluron was administered continuously to Ae. aegypti larvae, since early third instar. Larval instar period duration was recorded from third instar until pupation. Chitin content was measured during third and fourth instars. Fourth instars were processed histochemically at the mesothorax region, stained with hematoxylin and eosin (HE for assessment of internal tissues, and labeled with WGA-FITC to reveal chitinized structures. In control larvae: i there is a chitin content increase during both third and fourth instars where late third instars contain more chitin than early fourth instars; ii thoracic organs and a continuous cuticle, closely associated with the underlying epidermis were observed; iii chitin was continuously present throughout integument cuticle. Novaluron treatment inhibited adult emergence, induced immature mortality, altered adult sex ratio and caused delay in larval development. Moreover, novaluron: i significantly affected chitin content during larval development; ii induced a discontinuous and altered cuticle in some regions while epidermis was often thinner or missing; iii rendered chitin cuticle presence discontinuous and less evident. In both control and novaluron larvae, chitin was present in the peritrophic matrix. This study showed quantitatively and qualitatively evidences of novaluron effects

  12. Rheological Properties of Aqueous Suspensions of Chitin Crystallites

    Science.gov (United States)

    Li; Revol; Marchessault

    1996-11-10

    Rheologically, suspensions of chitin crystallites are found to behave as other molecular liquid crystalline polymers (LCPs). The average hydrodynamic diameter of the crystallites in the suspension at pH 4 is determined to be approximately 80 nm using dynamic light scattering. Conductimetric and pH titration results show that the pKa of the crystallites is 6.3, which is the same as that reported for chitosan. In combination with phase diagrams, flow properties of isotropic, biphasic, and anisotropic chitin suspensions were investigated. For isotropic suspensions, a classical shear thinning behavior of rodlike particles is observed. In the case of biphasic suspensions, a two-regime curve is observed where tactoids first orient, deform, and then break up under a shearing force. Similar to other LCPs, a three-regime flow curve is found for the anisotropic suspensions. The viscosity-concentration curve exhibits a maximum at the phase separation concentration, and this maximum is less distinct with a decrease of the ionic strength. Secondary electroviscous effects due to strong particle-particle interactions influence the viscosity of the suspensions at higher concentrations. PMID:8954679

  13. Anticancer activity of chemically prepared shrimp low molecular weight chitin evaluation with the human monocyte leukaemia cell line, THP-1.

    Science.gov (United States)

    Salah, R; Michaud, P; Mati, F; Harrat, Z; Lounici, H; Abdi, N; Drouiche, N; Mameri, N

    2013-01-01

    In the present study, anticancer activities of chitin, chitosan and low molecular weight chitin were evaluated using a human tumour cell line, THP-1. A molecular weight-activity relationship and an electrostatic interaction-activity relationship were determined. The cytotoxic effects of chitin and derivatives were also evaluated using a normal human foetal lung fibroblastic cell line, MRC-5 and the specific cytotoxicity of chitin and derivatives to tumour cell lines was demonstrated. The high antitumour effect of low molecular weight of chitin was established.

  14. Salmonella biofilm formation on Aspergillus niger involves cellulose--chitin interactions.

    Directory of Open Access Journals (Sweden)

    Maria T Brandl

    Full Text Available Salmonella cycles between host and nonhost environments, where it can become an active member of complex microbial communities. The role of fungi in the environmental adaptation of enteric pathogens remains relatively unexplored. We have discovered that S. enterica Typhimurium rapidly attaches to and forms biofilms on the hyphae of the common fungus, Aspergillus niger. Several Salmonella enterica serovars displayed a similar interaction, whereas other bacterial species were unable to bind to the fungus. Bacterial attachment to chitin, a major constituent of fungal cell walls, mirrored this specificity. Pre-incubation of S. Typhimurium with N-acetylglucosamine, the monomeric component of chitin, reduced binding to chitin beads by as much as 727-fold and inhibited attachment to A. niger hyphae considerably. A cellulose-deficient mutant of S. Typhimurium failed to attach to chitin beads and to the fungus. Complementation of this mutant with the cellulose operon restored binding to chitin beads to 79% of that of the parental strain and allowed for attachment and biofilm formation on A. niger, indicating that cellulose is involved in bacterial attachment to the fungus via the chitin component of its cell wall. In contrast to cellulose, S. Typhimurium curli fimbriae were not required for attachment and biofilm development on the hyphae but were critical for its stability. Our results suggest that cellulose-chitin interactions are required for the production of mixed Salmonella-A. niger biofilms, and support the hypothesis that encounters with chitinaceous alternate hosts may contribute to the ecological success of human pathogens.

  15. Antifungal curcumin promotes chitin accumulation associated with decreased virulence of Sporothrix schenckii.

    Science.gov (United States)

    Huang, Lilin; Zhang, Jing; Song, Tianzhang; Yuan, Liyan; Zhou, Junjie; Yin, Hongling; He, Tailong; Gao, Wenchao; Sun, Yao; Hu, Xuchu; Huang, Huaiqiu

    2016-05-01

    Curcumin, a yellow polyphenol compound, is known to possess antifungal activity for a range of pathogenic fungi. However, the fungicidal mechanism of curcumin (CUR) has not been identified. We have occasionally found that chitin redistributes to the cell wall outer layer of Sporothrix schenckii (S. schenckii) upon sublethal CUR treatment. Whether CUR can affect chitin synthesis via the protein kinase C (PKC) signaling pathway has not been investigated. This study describes a direct fungicidal activity of CUR against S. schenckii demonstrated by the results of a checkerboard microdilution assay and, for the first time, a synergistic effect of CUR with terbinafine (TRB). Furthermore, the results of real-time PCR showed that sublethal CUR upregulated the transcription of PKC, chitin synthase1 (CHS1), and chitin synthase3 (CHS3) in S. schenckii. The fluorescence staining results using wheat germ agglutinin-fluorescein isothiocyanate (WGA-FITC) and calcofluor white (CFW) consistently showed that chitin exposure and total chitin content were increased on the conidial cell wall of S. schenckii by sublethal CUR treatment. A histopathological analysis of mice infected with CUR-treated conidia showed dampened inflammation in the local lesion and a reduced fungal burden. The ELISA results showed proinflammatory cytokine secretion at an early stage from macrophages stimulated by the CUR-treated conidia. The present data led to the conclusion that CUR is a potential antifungal agent and that its fungicidal mechanism may involve chitin accumulation on the cell wall of S. schenckii, which is associated with decreased virulence in infected mice.

  16. Chitin enhances biocontrol of Rhodotorula mucilaginosa to postharvest decay of peaches.

    Science.gov (United States)

    Zhang, Hongyin; Yang, Qiya; Ge, Lingling; Zhang, Guochao; Zhang, Xiaoli; Zhang, Xiaoyun

    2016-07-01

    Biological control using microbial antagonists is a promising alternative approach to synthetic fungicides. However, effective biological control requires enhancing the consistency and efficacy of the antagonists used to control postharvest diseases. This study investigated the effect of chitin on the biocontrol efficacy of Rhodotorula mucilaginosa against blue mold and Rhizopus decay of peaches and on the protein expression profiles of R. mucilaginosa. The antagonistic activity of R. mucilaginosa harvested from the nutrient yeast dextrose broth (NYDB) with 0.5% chitin added was significantly improved compared with culture in NYDB without chitin. The R. mucilaginosa population cultured in chitin-supplement NYDB and nutrient yeast chitin borth (NYCB) harvested from peach wounds was more than that of R. mucilaginosa cultured in NYDB without chitin throughout the storage period except at 1 d. The protein expression profiles findings revealed that there were several differentially expressed proteins of R. mucilaginosa in the 0.5% chitin-supplemented NYDB and NYCB compared with that of R. mucilaginosa in NYDB. Most of these were cellular proteomes relating to the primary metabolic reactions such as glycoside hydrolases, phosphoribosyl pyrophosphate, and NADH dehydrogenases. Some proteins were also related to signal transmission and stress response. PMID:27064085

  17. Polycaprolactone-Chitin Nanofibrous Mats as Potential Scaffolds for Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Min Sup Kim

    2012-01-01

    Full Text Available We describe here the preparation of poly(caprolactone (PCL-chitin nanofibrous mats by electrospinning from a blended solution of PCL and chitin dissolved in a cosolvent, 1,1,1,3,3,3-hexafluoro-2-propanol and trifluoroacetic acid. Scanning electron microscopy showed that the neutralized PCL-chitin nanofibrous mats were morphologically stable, with a mean diameter of 340.5±2.6 nm, compared with a diameter of 524.2±12.1 nm for PCL mats. The nanofibrous mats showed decreased water contact angles as the proportion of chitin increased. However, the tensile properties of nanofibrous mats containing 30~50% (wt/wt chitin were enhanced compared with PCL-only mats. In vitro studies showed that the viability of human dermal fibroblasts (HDFs for up to 7 days in culture was higher on composite (OD value: 1.42±0.09 than on PCL-only (0.51±0.14 nanofibrous mats, with viability correlated with chitin concentration. Together, our results suggest that PCL-chitin nanofibrous mats can be used as an implantable substrate to modulate HDF viability in tissue engineering.

  18. FIBCD1 Modulation of the Epithelial Immune Response Elicited by Chitin

    DEFF Research Database (Denmark)

    Hammond, Mark; Schlosser, Anders; Bak-Thomsen, Theresa Helene;

    2010-01-01

    implicated in allergic and helminth immunity. However, very little is known about how chitin-induced immune signalling is initiated or propagated. Aim: The aim of this project is to investigate the hypothesis that chitin immune signalling may be initiated by the FIBCD1 chitin receptor through activation...... or the model ligand acetylated BSA, at different time intervals anddoses and using a luciferase reporter system detection of NFjB activation will be performed and cytokine expression will be quantified via qRT-PCR. Perspectives: Improved understanding of epithelialimmune and inflammatory modulation in response...

  19. Solvothermal synthesis of hydrophobic chitin-polyhedral oligomeric silsesquioxane (POSS) nanocomposites.

    Science.gov (United States)

    Wysokowski, Marcin; Materna, Katarzyna; Walter, Juliane; Petrenko, Iaroslav; Stelling, Allison L; Bazhenov, Vasilii V; Klapiszewski, Łukasz; Szatkowski, Tomasz; Lewandowska, Olga; Stawski, Dawid; Molodtsov, Serguei L; Maciejewski, Hieronim; Ehrlich, Hermann; Jesionowski, Teofil

    2015-01-01

    Chitinous scaffolds isolated from the skeleton of marine sponge Aplysina cauliformis were used as a template for the deposition of polyhedral oligomeric silsesquioxanes (POSS). These chitin-POSS based composites with hydrophobic properties were prepared for the first time using solvothermal synthesis (pH 3, temp 80 °C), and were thoroughly characterized. The resulting material was studied using scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and thermogravimetry. A mechanism for the chitin-POSS interaction after exposure to these solvothermal conditions is proposed and discussed. PMID:25889055

  20. Polycaprolactone-Chitin Nanofibrous Mats as Potential Scaffolds for Tissue Engineering

    OpenAIRE

    Min Sup Kim; Sang Jun Park; Bon Kang Gu; Chun-Ho Kim

    2012-01-01

    We describe here the preparation of poly(caprolactone) (PCL)-chitin nanofibrous mats by electrospinning from a blended solution of PCL and chitin dissolved in a cosolvent, 1,1,1,3,3,3-hexafluoro-2-propanol and trifluoroacetic acid. Scanning electron microscopy showed that the neutralized PCL-chitin nanofibrous mats were morphologically stable, with a mean diameter of 340.5±2.6 nm, compared with a diameter of 524.2±12.1 nm for PCL mats. The nanofibrous mats showed decreased water contact angle...

  1. Chitin and chitosan based polyurethanes: A review of recent advances and prospective biomedical applications.

    Science.gov (United States)

    Usman, Ali; Zia, Khalid Mahmood; Zuber, Mohammad; Tabasum, Shazia; Rehman, Saima; Zia, Fatima

    2016-05-01

    Chitin and chitosan are amino polysaccharides having massive structural propensities to produce bioactive materials with innovative properties, functions and diverse applications particularly in biomedical field. The specific physico-chemical, mechanical, biological and degradation properties offer efficient way to blend these biopolymers with synthetic ones. Polyurethane (PU) gained substantial attention owing to its structure-properties relationship. The immense activities of chitin/chitosan are successfully utilized to enhance the bioactive properties of polyurethanes. This review shed a light on chitin and chitosan based PU materials with their potential applications especially focusing the bio-medical field. All the technical scientific issues have been addressed highlighting the recent advancement in the biomedical field.

  2. Effects of chitin and its derivatives on human cancer cells lines.

    Science.gov (United States)

    Bouhenna, M; Salah, R; Bakour, R; Drouiche, N; Abdi, N; Grib, H; Lounici, H; Mameri, N

    2015-10-01

    The present study is focused on the effect of chitin derivatives against human cancer cell lines RD and Hep2. As an outcome from this research, chitin was cytotoxic at IC50 = 400 μg/ml and 200 μg/ml against Hep2 cells and RD cells lines, respectively. Irradiated chitin had an IC50 value of 450 μg/ml for Hep2 and an IC50 of 200 μg/ml for RD. The lowest IC50 is attributed to chitosan, 300 μg/ml in Hep2 and 190 μg/ml in RD.

  3. Chitins and chitosans as immunoadjuvants and non-allergenic drug carriers.

    Science.gov (United States)

    Muzzarelli, Riccardo A A

    2010-02-21

    Due to the fact that some individuals are allergic to crustaceans, the presumed relationship between allergy and the presence of chitin in crustaceans has been investigated. In vivo, chitin is part of complex structures with other organic and inorganic compounds: in arthropods chitin is covalently linked to proteins and tanned by quinones, in fungi it is covalently linked to glucans, while in bacteria chitin is diversely combined according to Gram(+/-) classification. On the other hand, isolated, purified chitin is a plain polysaccharide that, at the nano level, presents itself as a highly associated structure, recently refined in terms of regularity, nature of bonds, crystallinity degree and unusual colloidal behavior. Chitins and modified chitins exert a number of beneficial actions, i.e., (i) they stimulate macrophages by interacting with receptors on the macrophage surface that mediate the internalization of chitin particles to be degraded by lysozyme and N-acetyl-beta-glucosaminidase (such as Nod-like, Toll-like, lectin, Dectin-1, leukotriene 134 and mannose receptors); (ii) the macrophages produce cytokines and other compounds that confer non-specific host resistance against bacterial and viral infections, and anti-tumor activity; (iii) chitin is a strong Th1 adjuvant that up-regulates Th1 immunity induced by heat-killed Mycobacterium bovis, while down- regulating Th2 immunity induced by mycobacterial protein; (iv) direct intranasal application of chitin microparticles into the lung was also able to significantly down-regulate allergic response to Dermatophagoids pteronyssinus and Aspergillus fumigatus in a murine model of allergy; (v) chitin microparticles had a beneficial effect in preventing and treating histopathologic changes in the airways of asthmatic mice; (vi) authors support the fact that chitin depresses the development of adaptive type 2 allergic responses. Since the expression of chitinases, chitrotriosidase and chitinase-like proteins is greatly

  4. Chitins and Chitosans as Immunoadjuvants and Non-Allergenic Drug Carriers

    Directory of Open Access Journals (Sweden)

    Riccardo A. A. Muzzarelli

    2010-02-01

    Full Text Available Due to the fact that some individuals are allergic to crustaceans, the presumed relationship between allergy and the presence of chitin in crustaceans has been investigated. In vivo, chitin is part of complex structures with other organic and inorganic compounds: in arthropods chitin is covalently linked to proteins and tanned by quinones, in fungi it is covalently linked to glucans, while in bacteria chitin is diversely combined according to Gram(+/- classification. On the other hand, isolated, purified chitin is a plain polysaccharide that, at the nano level, presents itself as a highly associated structure, recently refined in terms of regularity, nature of bonds, crystallinity degree and unusual colloidal behavior. Chitins and modified chitins exert a number of beneficial actions, i.e., (i they stimulate macrophages by interacting with receptors on the macrophage surface that mediate the internalization of chitin particles to be degraded by lysozyme and N-acetyl-β-glucosaminidase (such as Nod-like, Toll-like, lectin, Dectin-1, leukotriene 134 and mannose receptors; (ii the macrophages produce cytokines and other compounds that confer non-specific host resistance against bacterial and viral infections, and anti-tumor activity; (iii chitin is a strong Th1 adjuvant that up-regulates Th1 immunity induced by heat-killed Mycobacterium bovis, while down- regulating Th2 immunity induced by mycobacterial protein; (iv direct intranasal application of chitin microparticles into the lung was also able to significantly down-regulate allergic response to Dermatophagoids pteronyssinus and Aspergillus fumigatus in a murine model of allergy; (v chitin microparticles had a beneficial effect in preventing and treating histopathologic changes in the airways of asthmatic mice; (vi authors support the fact that chitin depresses the development of adaptive type 2 allergic responses. Since the expression of chitinases, chitrotriosidase and chitinase-like proteins

  5. Chitin elicitation of natural product production in marine bacteria

    DEFF Research Database (Denmark)

    Månsson, Maria; Wietz, Matthias; Larsen, Thomas Ostenfeld;

    on glucose-based medium. The different phenotypic responses to a natural growth substrate may reflect different niche-adaptations or ecological functions of the compounds produced and it represents a fruitful approach for elicitation of natural product production in marine bacteria.......Genome sequences reveal that our current standard laboratory conditions only support a fraction of the potential secondary metabolism in bacteria.1 Thus, we must rethink cultivation, detection, and isolation strategies for bacterial secondary metabolites in order to explore the huge, so far...... uncharacterized chemical potential of these organisms. As part of a new project on ecology-driven drug discovery at the Technical University of Denmark, we investigate the use of chitin to elicit or alter production of antibacterial compounds in marine bacteria. Within our large collection of Gram...

  6. MICROBIAL FERMENTATION OF ABUNDANT BIOPOLYMERS: CELLULOSE AND CHITIN

    Energy Technology Data Exchange (ETDEWEB)

    Leschine, Susan

    2009-10-31

    Our research has dealt with seven major areas of investigation: i) characterization of cellulolytic members of microbial consortia, with special attention recently given to Clostridium phytofermentans, a bacterium that decomposes cellulose and produces uncommonly large amounts of ethanol, ii) investigations of the chitinase system of Cellulomonas uda; including the purification and characterization of ChiA, the major component of this enzyme system, iii) molecular cloning, sequence and structural analysis of the gene that encodes ChiA in C. uda, iv) biofilm formation by C. uda on nutritive surfaces, v) investigations of the effects of humic substances on cellulose degradation by anaerobic cellulolytic microbes, vi) studies of nitrogen metabolism in cellulolytic anaerobes, and vii) understanding the molecular architecture of the multicomplex cellulase-xylanase system of Clostridium papyrosolvens. Also, progress toward completing the research of more recent projects is briefly summarized. Major accomplishments include: 1. Characterization of Clostridium phytofermentans, a cellulose-fermenting, ethanol-producing bacterium from forest soil. The characterization of a new cellulolytic species isolated from a cellulose-decomposing microbial consortium from forest soil was completed. This bacterium is remarkable for the high concentrations of ethanol produced during cellulose fermentation, typically more than twice the concentration produced by other species of cellulolytic clostridia. 2. Examination of the use of chitin as a source of carbon and nitrogen by cellulolytic microbes. We discovered that many cellulolytic anaerobes and facultative aerobes are able to use chitin as a source of both carbon and nitrogen. This major discovery expands our understanding of the biology of cellulose-fermenting bacteria and may lead to new applications for these microbes. 3. Comparative studies of the cellulase and chitinase systems of Cellulomonas uda. Results of these studies indicate

  7. Three-dimensional chitin rings from body segments of a pet diplopod species: Characterization and protein interaction studies.

    Science.gov (United States)

    Kaya, Murat; Mulerčikas, Povilas; Sargin, Idris; Kazlauskaitė, Sonata; Baublys, Vykintas; Akyuz, Bahar; Bulut, Esra; Tubelytė, Vaida

    2016-11-01

    Physicochemical characterization of new chitin isolates can provide valuable insights into designing of biomimetic materials. Chitin isolates with a definite three-dimensional (3D) structure can exhibit characteristics that distinguish them from other chitin specimens that are in form of powder or flakes without a definite and uniform shape. Herein, 3D chitin rings were produced from body segments of a diplopod (Archispirostreptus gigas) inhabiting tropical regions. This organism is cultured easily and can reach 38cm in length, which makes it a suitable source for isolation of chitin. The chitin rings were characterized via TGA, FT-IR, SEM and XRD analyses. Enzymatic digestion test with chitinase demonstrated that chitin isolates had high purity (digestion rate: 97.4%). The source organism had high chitin content; 21.02±2.23% on dry weight. Interactions of the chitin rings with bovine serum albumin (BSA) protein were studied under different conditions (pH: 4.0-8.0, chitin amount: 6-14mg, contact time: 30-360min, protein concentration: 0.2-1mg/mL). The highest BSA adsorption was observed at pH5.0 at 20°C. The adsorption equilibrium data exhibited a better fit to Langmuir adsorption and the pseudo-first order kinetic models. The findings presented here can be useful for further studies aiming to develop biocompatible and nontoxic biomaterials. PMID:27524072

  8. The structure of mollusc larval shells formed in the presence of the chitin synthase inhibitor Nikkomycin Z

    Directory of Open Access Journals (Sweden)

    Weiss Ingrid M

    2007-11-01

    Full Text Available Abstract Background Chitin self-assembly provides a dynamic extracellular biomineralization interface. The insoluble matrix of larval shells of the marine bivalve mollusc Mytilus galloprovincialis consists of chitinous material that is distributed and structured in relation to characteristic shell features. Mollusc shell chitin is synthesized via a complex transmembrane chitin synthase with an intracellular myosin motor domain. Results Enzymatic mollusc chitin synthesis was investigated in vivo by using the small-molecule drug NikkomycinZ, a structural analogue to the sugar donor substrate UDP-N-acetyl-D-glucosamine (UDP-GlcNAc. The impact on mollusc shell formation was analyzed by binocular microscopy, polarized light video microscopy in vivo, and scanning electron microscopy data obtained from shell material formed in the presence of NikkomycinZ. The partial inhibition of chitin synthesis in vivo during larval development by NikkomycinZ (5 μM – 10 μM dramatically alters the structure and thus the functionality of the larval shell at various growth fronts, such as the bivalve hinge and the shell's edges. Conclusion Provided that NikkomycinZ mainly affects chitin synthesis in molluscs, the presented data suggest that the mollusc chitin synthase fulfils an important enzymatic role in the coordinated formation of larval bivalve shells. It can be speculated that chitin synthesis bears the potential to contribute via signal transduction pathways to the implementation of hierarchical patterns into chitin mineral-composites such as prismatic, nacre, and crossed-lamellar shell types.

  9. Degradation of barnacle nauplii: Implications to chitin regulation in the marine environment

    Digital Repository Service at National Institute of Oceanography (India)

    Khandeparker, L.; Gaonkar, C.C.; Desai, D.V.

    The exoskeleton of most invertebrate larval forms is made of chitin, which is a linear polysaccharide of beta (1→4)-linked N-acetylglucosamine (GlcNAc) residues. These larval forms offer extensive body surface for bacterial attachment...

  10. In vitro degradation of porous nano-hydroxyapatite/collagen/PLLA scaffold reinforced by chitin fibres

    International Nuclear Information System (INIS)

    In this paper, a novel porous scaffold for bone tissue engineering was prepared with nano-hydroxyapatite/collagen/Poly-L-lactic acid (PLLA) composite reinforced by chitin fibres. To enhance the strength of the scaffold further, PLLA was linked with chitin fibres by Dicyclohexylcarbodimide (DCC). The structures of the reinforced scaffold with and without linking were characterized by Scanning Electron Microscopy (SEM). The chemical characteristics of the chitin fibres with and without linking were evaluated by Fourier-transformed infrared (FTIR) spectroscopy. The mechanical performance during degradation in vitro was investigated. The results indicated that the nano-hydroxyapatite/collagen/PLLA composite reinforced by chitin fibres with linking kept better mechanical properties than that of the composite without linking. These results denoted that the stronger interfacial bonding strength of the scaffold with linking could decrease the degradation rate in vitro. The reinforced composite with the link-treatment can be severed as a scaffold for bone tissue engineering

  11. Enhanced enzymatic hydrolysis of langostino shell chitin with mixtures of enzymes from bacterial and fungal sources.

    Science.gov (United States)

    Donzelli, Bruno G G; Ostroff, Gary; Harman, Gary E

    2003-09-01

    A combination of enzyme preparations from Trichoderma atroviride and Serratia marcescens was able to completely degrade high concentrations (100 g/L) of chitin from langostino crab shells to N-acetylglucosamine (78%), glucosamine (2%), and chitobiose (10%). The result was achieved at 32 degrees C in 12 days with no pre-treatment (size reduction or swelling) of the substrate and without removal of the inhibitory end-products from the mixture. Enzymatic degradation of three forms of chitin by Serratia/Trichoderma and Streptomyces/Trichoderma blends was carried out according to a simplex-lattice mixture design. Fitted polynomial models indicated that there was synergy between prokaryotic and fungal enzymes for both hydrolysis of crab chitin and reduction of turbidity of colloidal chitin (primarily endo-type activity). Prokaryotic/fungal enzymes were not synergistic in degrading chitosan. Enzymes from prokaryotic sources had much lower activity against chitosan than enzymes from T. atroviride.

  12. Chitin-Chitosan Yield of Freshwater Crab (Potamon potamios, Olivier 1804 Shell

    Directory of Open Access Journals (Sweden)

    Yildiz Bolat*, Şengül Bilgin, Ali Günlü, Levent Izci, Seval Bahadır Koca, Soner Çetinkaya1 and Habil Uğur Koca

    2010-10-01

    Full Text Available In this study, freshwater crab (Potamon potamios, Olivier 1804, economically unevaluated, was used to obtain chitin-chitosan. Chitin-chitosan was extracted with standardized modified chemical method. Chitosan was extracted with demineralization, deproteinization, decoloration (chitin and deacetylation (chitosan. Grinded shell was obtained as 60% after boiling, drying and grinding processes. Chitosan yield of crab shell was determined as 4.65% from grinded crab shell after demineralization (yield is 34.32%, deproteinization (yield is 7.25%, decoloration (yield is 6.83% and deacetylation processes. Moreover, freshwater crab stock was estimated with catch per unit effort (CPUE data in Eğirdir Lake for calculation of quantity of chitosan. Population size was estimated between 12.85±11.88 and 23.86±25.39 tones and freshwater crab was determined as an appropriate crustacean to obtain chitin-chitosan.

  13. Adsorption of Heavy Metal Ions by Adsorbent from Waste Mycelium Chitin

    Institute of Scientific and Technical Information of China (English)

    苏海佳; 王丽娟; 等

    2002-01-01

    The adsorption properties of chitin adsorbent from mycelium of fermentation industries for the removal of heavy metal ions were studied.The result shows that the chitin adsorbent has high adsorption capacity for many heavy metal ions and Ni2+ in citric acid.The influence of pH was significant:When pH is higher than 4.0,the high adsorption capacity is obtained.otherwise H+ ion inhibits the adsorption of heavy metal ions.The comparison of the chitin adsorbent with some other commercial adsorbents was made,in which that the adsorption behavior of chitin adsorbent is close to that of commercial cation exchange adsorbents,and its cost is much lower than those commercial adsorbents.

  14. Infiltration of chitin by protein coacervates defines the squid beak mechanical gradient.

    Science.gov (United States)

    Tan, YerPeng; Hoon, Shawn; Guerette, Paul A; Wei, Wei; Ghadban, Ali; Hao, Cai; Miserez, Ali; Waite, J Herbert

    2015-07-01

    The beak of the jumbo squid Dosidicus gigas is a fascinating example of how seamlessly nature builds with mechanically mismatched materials. A 200-fold stiffness gradient begins in the hydrated chitin of the soft beak base and gradually increases to maximum stiffness in the dehydrated distal rostrum. Here, we combined RNA-Seq and proteomics to show that the beak contains two protein families. One family consists of chitin-binding proteins (DgCBPs) that physically join chitin chains, whereas the other family comprises highly modular histidine-rich proteins (DgHBPs). We propose that DgHBPs play multiple key roles during beak bioprocessing, first by forming concentrated coacervate solutions that diffuse into the DgCBP-chitin scaffold, and second by inducing crosslinking via an abundant GHG sequence motif. These processes generate spatially controlled desolvation, resulting in the impressive biomechanical gradient. Our findings provide novel molecular-scale strategies for designing functional gradient materials. PMID:26053298

  15. Application of Spectroscopic Methods for Structural Analysis of Chitin and Chitosan

    Directory of Open Access Journals (Sweden)

    Jolanta Kumirska

    2010-04-01

    Full Text Available Chitin, the second most important natural polymer in the world, and its N-deacetylated derivative chitosan, have been identified as versatile biopolymers for a broad range of applications in medicine, agriculture and the food industry. Two of the main reasons for this are firstly the unique chemical, physicochemical and biological properties of chitin and chitosan, and secondly the unlimited supply of raw materials for their production. These polymers exhibit widely differing physicochemical properties depending on the chitin source and the conditions of chitosan production. The presence of reactive functional groups as well as the polysaccharide nature of these biopolymers enables them to undergo diverse chemical modifications. A complete chemical and physicochemical characterization of chitin, chitosan and their derivatives is not possible without using spectroscopic techniques. This review focuses on the application of spectroscopic methods for the structural analysis of these compounds.

  16. Chitin-Induced Airway Epithelial Cell Innate Immune Responses Are Inhibited by Carvacrol/Thymol

    Science.gov (United States)

    Erle, David J.

    2016-01-01

    Chitin is produced in large amounts by fungi, insects, and other organisms and has been implicated in the pathogenesis of asthma. Airway epithelial cells are in direct contact with environmental particles and serve as the first line of defense against inhaled allergens and pathogens. The potential contributions of airway epithelial cells to chitin-induced asthma remain poorly understood. We hypothesized that chitin directly stimulates airway epithelial cells to release cytokines that promote type 2 immune responses and to induce expression of molecules which are important in innate immune responses. We found that chitin exposure rapidly induced the expression of three key type 2-promoting cytokines, IL-25, IL-33 and TSLP, in BEAS-2B transformed human bronchial epithelial cells and in A549 and H292 lung carcinoma cells. Chitin also induced the expression of the key pattern recognition receptors TLR2 and TLR4. Chitin induced the expression of miR-155, miR-146a and miR-21, each of which is known to up-regulate the expression of pro-inflammatory cytokines. Also the expression of SOCS1 and SHIP1 which are known targets of miR-155 was repressed by chitin treatment. The monoterpene phenol carvacrol (Car) and its isomer thymol (Thy) are found in herbal essential oils and have been shown to inhibit allergic inflammation in asthma models. We found that Car/Thy inhibited the effects of chitin on type 2-promoting cytokine release and on the expression of TLRs, SOCS1, SHIP1, and miRNAs. Car/Thy could also efficiently reduce the protein levels of TLR4, inhibit the increase in TLR2 protein levels in chitin plus Car/Thy-treated cells and increase the protein levels of SHIP1 and SOCS1, which are negative regulators of TLR-mediated inflammatory responses. We conclude that direct effects of chitin on airway epithelial cells are likely to contribute to allergic airway diseases like asthma, and that Car/Thy directly inhibits epithelial cell pro-inflammatory responses to chitin. PMID

  17. Preparation, assessment, and comparison of α-chitin nano-fiber films with different surface charges

    Science.gov (United States)

    Zhang, Yan; Jiang, Jie; Liu, Liang; Zheng, Ke; Yu, Shiyuan; Fan, Yimin

    2015-05-01

    Chitin nano-fibers with positive and negative charges have been, respectively, produced from partially deacetylated and 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated oxidized α-chitin. The average diameters and lengths of the TEMPO-oxidized chitin nano-fibers (TOChN) were 14 ± 4.3 and 190 ± 140 nm, respectively, and the average diameters and lengths of the partially deacetylated chitin nano-fibers (DEChN) were 6 ± 1.7 and 320 ± 105 nm, respectively. A partially deacetylated chitin nano-fiber film (DEChN-F), a TEMPO-mediated and oxidized chitin nano-fiber film (TOChN-F), and a composite film (DE-TO-ChN-F) consisting of a combination of the two were prepared by drying the dispersions at 40 °C. The DEChN-F, TOChN-F, and DE-TO-ChN-F all have similar tensile strengths of approximately 90 MPa; however, the chitosan film (Chitosan-F) had a tensile strength of approximately 30 MPa. In addition, TOChN-F and DE-TO-ChN-F have a thermal weight loss at 210 °C, and DEChN-F has a thermal weight loss at 280 °C. DEChN-F was found to have antimicrobial activity with regards to Escherichia coli. Finally, the chitin nano-fiber films could be slightly degraded by cellulase, which provided a novel biological performance of the chitin nano-material.

  18. Chitin, Chitosan, and Glycated Chitosan Regulate Immune Responses: The Novel Adjuvants for Cancer Vaccine

    OpenAIRE

    Xiaosong Li; Min Min; Nan Du; Ying Gu; Tomas Hode; Mark Naylor; Dianjun Chen; Nordquist, Robert E.; Chen, Wei R.

    2013-01-01

    With the development of cancer immunotherapy, cancer vaccine has become a novel modality for cancer treatment, and the important role of adjuvant has been realized recently. Chitin, chitosan, and their derivatives have shown their advantages as adjuvants for cancer vaccine. In this paper, the adjuvant properties of chitin and chitosan were discussed, and some detailed information about glycated chitosan and chitosan nanoparticles was also presented to illustrate the trend for future development.

  19. Bridging peripheral nerves using a deacetyl chitin conduit combined with short-term electrical stimulation

    OpenAIRE

    Zhang, Zhongli; Xin LI; Zuo, Songjie; Xin, Jie; Zhang, Peixun

    2014-01-01

    Previous studies have demonstrated that deacetyl chitin conduit nerve bridging or electrical stimulation can effectively promote the regeneration of the injured peripheral nerve. We hypothesized that the combination of these two approaches could result in enhanced regeneration. Rats with right sciatic nerve injury were subjected to deacetyl chitin conduit bridging combined with electrical stimulation (0.1 ms, 3 V, 20 Hz, for 1 hour). At 6 and 12 weeks after treatment, nerve conduction velocit...

  20. Hydrogen and oxygen in brine shrimp chitin reflect environmental water and dietary isotopic composition

    Science.gov (United States)

    Nielson, Kristine E.; Bowen, Gabriel J.

    2010-03-01

    Hydrogen and oxygen isotope ratios of the common structural biopolymer chitin are a potential recorder of ecological and environmental information, but our understanding of the mechanisms of incorporation of H and O from environmental substrates into chitin is limited. We report the results of a set of experiments in which the isotopic compositions of environmental water and diet were varied independently in order to assess the contribution of these variables to the H and O isotopic composition of Artemia franciscana chitin. Hydrogen isotope ratios of chitin were strongly linearly correlated with both food and water, with approximately 26% of the hydrogen signal reflecting food and approximately 38% reflecting water. Oxygen isotopes were also strongly correlated with the isotopic composition of water and food, but whereas 69% of oxygen in chitin exchanged with environmental water, only 10% was derived from food. We propose that these observations reflect the position-specific, partial exchange of H and O atoms with brine shrimp body water during the processes of digestion and chitin biosynthesis. Comparison of culture experiments with a set of natural samples collected from the Great Salt Lake, UT in 2006 shows that, with some exceptions, oxygen isotope compositions of chitin track those of water, whereas hydrogen isotopes vary inversely with those of lake water. The different behavior of the two isotopic systems can be explained in terms of a dietary shift from allochthonous particulate matter with relatively higher δ 2H values in the early spring to autochthonous particulate matter with significantly lower δ 2H values in the late summer to autumn. These results suggest oxygen in chitin may be a valuable proxy for the oxygen isotopic composition of environmental water, whereas hydrogen isotope values from the same molecule may reveal ecological and biogeochemical changes within lakes.

  1. Infiltration of chitin by protein coacervates defines the squid beak mechanical gradient

    OpenAIRE

    Y. Tan; Hoon, S; Guerette, PA; Wei, W; Ghadban, A; Hao, C; Miserez, A; Waite, JH

    2015-01-01

    © 2015 Nature America, Inc. All rights reserved. The beak of the jumbo squid Dosidicus gigas is a fascinating example of how seamlessly nature builds with mechanically mismatched materials. A 200-fold stiffness gradient begins in the hydrated chitin of the soft beak base and gradually increases to maximum stiffness in the dehydrated distal rostrum. Here, we combined RNA-Seq and proteomics to show that the beak contains two protein families. One family consists of chitin-binding proteins (DgCB...

  2. Isocyanate-Functionalized Chitin and Chitosan as Gelling Agents of Castor Oil

    OpenAIRE

    Franco, José M.; Rocío Gallego; Jesús F. Arteaga; Concepción Valencia

    2013-01-01

    The main objective of this work was the incorporation of reactive isocyanate groups into chitin and chitosan in order to effectively use the products as reactive thickening agents in castor oil. The resulting gel-like dispersions could be potentially used as biodegradable lubricating greases. Three different NCO–functionalized polymers were obtained: two of them by promoting the reaction of chitosan with 1,6-hexamethylene diisocyanate (HMDI), and the other by using chitin instead of chitosan....

  3. Laboratory Evaluation of Five Chitin Synthesis Inhibitors Against the Colorado Potato Beetle, Leptinotarsa decemlineata

    OpenAIRE

    Karimzadeh, R.; Hejazi, M. J.; Rahimzadeh Khoei, F.; Moghaddam, M.

    2007-01-01

    Results of laboratory experiments are reported that tested the effects of five chitin synthesis inhibitors, diflubenzuron, cyromazine, lufenuron, hexaflumuron and triflumuron. on second instars of the Colorado potato beetle, Leptinotarsa decemlineata (Say) (Coleoptera: Crysomelidae), originally collected from potato fields of Bostanabaad, a town 66 km southeast of Tabriz, Iran. In bioassays, the larvae were fed potato leaves dipped in aqueous solutions containing chitin synthesis inhibitors. ...

  4. Discussion remarks on the role of wood and chitin constituents during carbonization

    OpenAIRE

    Anna eIlnicka; Jerzy P Lukaszewicz

    2015-01-01

    Nature is a source of some biomaterials like wood and chitin which can be successfully transformed into chars of advanced structural/surface parameters. The manuscript is discursive and suggests that particular components of the materials (cellulose, lignin, hemicellulose, alfa-chitin fibrils, mineral-protein matrix) play a specific role in the manufacturing of porous chars. It is proposed that some of the components (hemicellulose and mineral-protein matrixes) behave like a natural soft temp...

  5. Discussion Remarks on the Role of Wood and Chitin Constituents during Carbonization

    OpenAIRE

    Ilnicka, Anna; Jerzy P Lukaszewicz

    2015-01-01

    Nature is a source of some biomaterials like wood and chitin, which can be successfully transformed into chars of advanced structural/surface parameters. The manuscript is discursive and suggests that particular components of the materials (cellulose, lignin, hemicellulose, alfa-chitin fibrils, mineral–protein matrix) play a specific role in the manufacturing of porous chars. It is proposed that some of the components (hemicellulose and mineral–protein matrixes) behave like a natural soft tem...

  6. Extraction biotechnologique de la chitine pour la production de chitosane : caractérisation et application

    OpenAIRE

    Pacheco Lopez, Neith

    2010-01-01

    The chitin is one of the most abundant biopolymers in biomass. Its main industrial derivative is the chitosan. These two polysaccharides present an increasing interest thanks to their various interesting physicochemical and biological properties. Their potential applications concern diverse fields as the pharmacy, medicine, food industry and agriculture. Despite numerous advances in methods for the chemical production of chitin and chitosan, the use of concentrated solutions of acids and alka...

  7. Nisin production in a chitin-including continuous fermentation system with Lactococcus lactis displaying a cell wall chitin-binding domain.

    Science.gov (United States)

    Şimşek, Ömer

    2014-03-01

    The limiting factors in the continuous production of nisin are high amount of biomass loss and low dilution rate application. In this study, a chitin-including continuous nisin fermentation system (CICON-FER) was constructed for high volumetric nisin production using nisin producer L. lactis displaying cell wall chitin-binding domain (ChBD) together with chitin in the reactor. In this respect, the highest binding conditions of relevant L. lactis cells to chitin were determined. Then the chitin flakes carrying nisin-producing L. lactis cells were used within the CICON-FER system at different dilution rates (0.1-0.9 h⁻¹) and initial glucose concentrations (20-60 g l⁻¹). The results revealed that the pH 7 conditions and the use of 100 mM sodium phosphate buffer with 0.1 % Tween 20 and Triton X-100 significantly increased the binding capacity of ChBD displaying L. lactis cells to chitin. The constructed CICON-FER system maintained the presence of the ChBD surface displaying L. lactis cells in the reactor system until 0.9 h⁻¹ dilution rate that resulted in a considerably high level of volumetric nisin production and productivity (10,500 IU ml⁻¹ and 9,450 IU ml⁻¹ h⁻¹, respectively) with the combination of a 0.9-h⁻¹ dilution rate and a 40-g l⁻¹ initial glucose concentration. In conclusion, an innovative nisin fermentation system that yielded the highest nisin production thus far and that was feasible for industrial application was created.

  8. Nature-Inspired One-Step Green Procedure for Enhancing the Antibacterial and Antioxidant Behavior of a Chitin Film: Controlled Interfacial Assembly of Tannic Acid onto a Chitin Film.

    Science.gov (United States)

    Wang, Yuntao; Li, Jing; Li, Bin

    2016-07-20

    The final goal of this study was to develop antimicrobial food-contact materials based on a natural phenolic compound (tannic acid) and chitin, which is the second most abundant polysaccharide on earth, using an interfacial assembly approach. Chitin film has poor antibacterial and antioxidant ability, which limits its application in industrial fields such as active packaging. Therefore, in this study, a novel one-step green procedure was applied to introduce antibacterial and antioxidant properties into a chitin film simultaneously by incorporation of tannic acid into the chitin film through interfacial assembly. The antibacterial and antioxidant behavior of chitin film has been greatly enhanced. Hydrogen bonds and hydrophobic interaction were found to be the main driving forces for interfacial assembly. Therefore, controlled interfacial assembly of tannic acid onto a chitin film demonstrated a good way to develop functional materials that can be potentially applied in industry. PMID:27378105

  9. Nature-Inspired One-Step Green Procedure for Enhancing the Antibacterial and Antioxidant Behavior of a Chitin Film: Controlled Interfacial Assembly of Tannic Acid onto a Chitin Film.

    Science.gov (United States)

    Wang, Yuntao; Li, Jing; Li, Bin

    2016-07-20

    The final goal of this study was to develop antimicrobial food-contact materials based on a natural phenolic compound (tannic acid) and chitin, which is the second most abundant polysaccharide on earth, using an interfacial assembly approach. Chitin film has poor antibacterial and antioxidant ability, which limits its application in industrial fields such as active packaging. Therefore, in this study, a novel one-step green procedure was applied to introduce antibacterial and antioxidant properties into a chitin film simultaneously by incorporation of tannic acid into the chitin film through interfacial assembly. The antibacterial and antioxidant behavior of chitin film has been greatly enhanced. Hydrogen bonds and hydrophobic interaction were found to be the main driving forces for interfacial assembly. Therefore, controlled interfacial assembly of tannic acid onto a chitin film demonstrated a good way to develop functional materials that can be potentially applied in industry.

  10. Facile route to produce chitin nanofibers as precursors for flexible and transparent gas barrier materials.

    Science.gov (United States)

    Wu, Jie; Zhang, Kuang; Girouard, Natalie; Meredith, J Carson

    2014-12-01

    Chitin is the second most abundant biopolymer in nature and has tremendous potential in renewable materials for packaging, energy storage, reinforced composites, and biomedical engineering. Despite attractive properties, including biodegradability, antibacterial activity, and high strength, chitin is not utilized widely due to strong molecular interactions, which make solubilization and processing difficult. We report a high pressure homogenization route to produce pure chitin nanofibers (ChNFs) starting with a mildly acidic aqueous dispersion of purified crab α-chitin. The well-dispersed ChNFs with diameter ∼20 nm do not form strong network structures under conditions explored herein and can be directly processed into useful materials, bypassing the need to dissolve the chitin. Dried ChNFs form pure self-standing chitin films with the lowest to-date reported O2 and CO2 permeabilities of 0.006 and 0.018 barrer, respectively. Combined with high flexibility and optical transparency, these materials are ideal candidates for sustainable barrier packaging. PMID:25483821

  11. Tight attachment of chitin-binding-domain-tagged proteins to surfaces coated with acetylated chitosan.

    Science.gov (United States)

    Bernard, Michael P; Cao, Donghui; Myers, Rebecca V; Moyle, William R

    2004-04-15

    Several excellent procedures for trapping tagged proteins have been devised, but many of these are expensive, cannot be used outside a limited pH range, fail to work in the presence of chaotropic agents, or are difficult to use. The chitin binding domain (CBD) of Bacillus circulans chitinase, which binds to chitin matrices prepared from inexpensive reagents isolated from crab shells, is an alternative tag that can be used under a variety of pH and denaturing conditions. Kits based on the interaction between the CBD and the chitin beads are available commercially. Here, we show that simultaneous treatment of microtiter plates with chitosan, a deacetylated form of chitin, and acetic anhydride produces a surface-bound film of chitin that also interacts tightly with the CBD. Chitin-coated microtiter well plates captured a CBD-tagged heterodimeric human glycoprotein hormone analog directly from mammalian cell culture media, even when present in trace amounts. Binding to the surface was stable in sodium dodecylsulfate and reversed only partially at low pH or in 8M urea at 37 degrees C. This technique appears well suited to surface attachment and permits biochemical or other analyses of molecules that can be tagged with a CBD.

  12. RECOVERY OF CHITIN AND CHITOSAN FROM SHRIMP WASTE BY CHEMICAL AND MICROBIAL METHODS

    Directory of Open Access Journals (Sweden)

    A. Khanafari, R. Marandi, Sh. Sanatei

    2008-01-01

    Full Text Available Shrimp waste is the most important chitin source for commercial use. In this study chitin and chitosan were extracted from Penaeus semisulcatus waste collected from a shrimp processing landing center situated at Persian Gulf in south of Iran by chemical and microbial methods. Chitin and chitosan were extracted by alkali-acid treatment and the yields were 510 and 410mg/g, respectively. Demineralization is an important step in the chitin purification process from shrimp waste. Chemical extraction method included the use of NaOH solution and acetic acid. In microbial extraction, organic acids (lactic acid produced by probiotic bacteria was used to demineralize microbial deproteinized shrimp shells. The study showed that the effectiveness of using lactic acid bacteria especially added Fe (NO33 as extra nitrogen source for demineralization of shrimp shells than chemical method (1750 against 810mg/g. Chitin and chitosan extracted from shrimp waste by chemical and microbial methods was crystalline powder, non-harmful and odorless, white and off-white, respectively. The moisture content was calculated as 63.8%. The amount of Ca, Fe, Cu and Mn present in the shells was 168, 35.58, 38.28 and 6.72mg/L, obtained by atomic absorption spectroscopy, respectively. The amount of calcium in the shells was 25 times higher than manganese. The results suggested Lactobacillus plantarum (PTTC 1058 is an attractive source of recovery for chitin and chitosan.

  13. Morphology and properties of soy protein isolate thermoplastics reinforced with chitin whiskers.

    Science.gov (United States)

    Lu, Yongshang; Weng, Lihui; Zhang, Lina

    2004-01-01

    Environmentally friendly thermoplastic nanocomposites were successfully developed using a colloidal suspension of chitin whiskers as a filler to reinforce soy protein isolate (SPI) plastics. The chitin whiskers, having lengths of 500 +/- 50 nm and diameters of 50 +/- 10 nm on average, were prepared from commercial chitin by acid hydrolysis. The dependence of morphology and properties on the chitin whiskers content in the range from 0 to 30 wt % for the glycerol plasticized SPI nanocomposites was investigated by dynamic mechanical thermal analysis, scanning electron microscopy, swelling experiment, and tensile testing. The results indicate that the strong interactions between fillers and between the filler and SPI matrix play an important role in reinforcing the composites without interfering with their biodegradability. The SPI/chitin whisker nanocomposites at 43% relative humidity increased in both tensile strength and Young's modulus from 3.3 MPa for the SPI sheet to 8.4 MPa and from 26 MPa for the SPI sheet to 158 MPa, respectively. Further, incorporating chitin whisker into the SPI matrix leads to an improvement in water resistance for the SPI based nanocomposites.

  14. The Plasmodiophora brassicae genome reveals insights in its life cycle and ancestry of chitin synthases.

    Science.gov (United States)

    Schwelm, Arne; Fogelqvist, Johan; Knaust, Andrea; Jülke, Sabine; Lilja, Tua; Bonilla-Rosso, German; Karlsson, Magnus; Shevchenko, Andrej; Dhandapani, Vignesh; Choi, Su Ryun; Kim, Hong Gi; Park, Ju Young; Lim, Yong Pyo; Ludwig-Müller, Jutta; Dixelius, Christina

    2015-01-01

    Plasmodiophora brassicae causes clubroot, a major disease of Brassica oil and vegetable crops worldwide. P. brassicae is a Plasmodiophorid, obligate biotrophic protist in the eukaryotic kingdom of Rhizaria. Here we present the 25.5 Mb genome draft of P. brassicae, developmental stage-specific transcriptomes and a transcriptome of Spongospora subterranea, the Plasmodiophorid causing powdery scab on potato. Like other biotrophic pathogens both Plasmodiophorids are reduced in metabolic pathways. Phytohormones contribute to the gall phenotypes of infected roots. We report a protein (PbGH3) that can modify auxin and jasmonic acid. Plasmodiophorids contain chitin in cell walls of the resilient resting spores. If recognized, chitin can trigger defense responses in plants. Interestingly, chitin-related enzymes of Plasmodiophorids built specific families and the carbohydrate/chitin binding (CBM18) domain is enriched in the Plasmodiophorid secretome. Plasmodiophorids chitin synthases belong to two families, which were present before the split of the eukaryotic Stramenopiles/Alveolates/Rhizaria/Plantae and Metazoa/Fungi/Amoebozoa megagroups, suggesting chitin synthesis to be an ancient feature of eukaryotes. This exemplifies the importance of genomic data from unexplored eukaryotic groups, such as the Plasmodiophorids, to decipher evolutionary relationships and gene diversification of early eukaryotes. PMID:26084520

  15. Unconventional Approach for Demineralization of Deproteinized Crustacean Shells for Chitin Production

    Directory of Open Access Journals (Sweden)

    N. S. Mahmoud

    2007-01-01

    Full Text Available Chitin is a versatile environmentally friendly modern material. It has a wide range of applications in areas such as water treatment, pulp and paper, biomedical devices and therapies, cosmetics, membrane technology and biotechnology and food applications. Crustacean waste is the most important chitin source for commercial use. Demineralization is an important step in the chitin purification process from crustacean waste. The conventional method of demineralization includes the use of strong acid (commonly HCl that harms the physiochemical properties of chitin, results in a harmful effluent wastewater and increases the cost of chitin purification process. The current study proposes the use of organic acids (lactic and acetic produced by cheese whey fermentation to demineralize microbially deproteinized shrimp shells. The effects of acid type, demineralization condition, retention time and shells to acid ratio were investigated. The study showed that the effectiveness of using lactic and/or acetic acids for demineralization of shrimp shells was comparable to that of using hydrochloric acid. Using organic acids for demineralization is a promising concept, since organic acids are less harmful to the environment, can preserve the characteristics of the purified chitin and can be produced from low cost biomass such as cheese whey. In addition, the resulted organic salts from the demineralization process can be used as a food preservative and/or an environmentally friendly de-icing/anti-icing agents.

  16. Production of High Viscosity Chitosan from Biologically Purified Chitin Isolated by Microbial Fermentation and Deproteinization

    Directory of Open Access Journals (Sweden)

    Ekkalak Ploydee

    2014-01-01

    Full Text Available The objective of this study was to produce high viscosity chitosan from shrimp chitin prepared by using a two-step biological treatment process: decalcification and deproteinization. Glucose was fermented with Lactobacillus pentosus L7 to lactic acid. At a pH of 3.9±0.1, the calcium carbonate of the shells was solubilized in 48 hours. The amounts of residual calcium in the form of ash (1.4±0.5% and crude protein (23.2±2.5% were further eliminated by the activity of proteolytic Bacillus thuringiensis SA. After decalcification and deproteinization of the shrimp shells, residual calcium and crude protein of shrimp chitin flakes were 1.7±0.4% and 3.8±1.3%, respectively. Chitin was deacetylated with 50% NaOH at 121°C for 5 hours. After deacetylation, the chitosan had residual calcium, crude protein content, and degree of acetylation of 1.6±0.6%, 0.4±0.3%, and 83.2±1.5%, respectively. The viscosity of chitosan prepared from chitin extracted by this two-step biological process was 1,007±14.7 mPa·s, whereas chitosan prepared from chemically processed chitin had a viscosity of 323±15.6   mPa·s, indicating that biologically purified chitin gave chitosan with a high quality.

  17. Nanostructural Organization of Naturally Occurring Composites—Part II: Silica-Chitin-Based Biocomposites

    Directory of Open Access Journals (Sweden)

    Hermann Ehrlich

    2008-01-01

    Full Text Available Investigations of the micro- and nanostructures and chemical composition of the sponge skeletons as examples for natural structural biocomposites are of fundamental scientific relevance. Recently, we show that some demosponges (Verongula gigantea, Aplysina sp. and glass sponges (Farrea occa, Euplectella aspergillum possess chitin as a component of their skeletons. The main practical approach we used for chitin isolation was based on alkali treatment of corresponding external layers of spicules sponge material with the aim of obtaining alkali-resistant compounds for detailed analysis. Here, we present a detailed study of the structural and physicochemical properties of spicules of the glass sponge Rossella fibulata. The structural similarity of chitin derived from this sponge to invertebrate alpha chitin has been confirmed by us unambiguously using physicochemical and biochemical methods. This is the first report of a silica-chitin composite biomaterial found in Rossella species. Finally, the present work includes a discussion related to strategies for the practical application of silica-chitin-based composites as biomaterials.

  18. A carnivorous sundew plant prefers protein over chitin as a source of nitrogen from its traps.

    Science.gov (United States)

    Pavlovič, Andrej; Krausko, Miroslav; Adamec, Lubomír

    2016-07-01

    Carnivorous plants have evolved in nutrient-poor wetland habitats. They capture arthropod prey, which is an additional source of plant growth limiting nutrients. One of them is nitrogen, which occurs in the form of chitin and proteins in prey carcasses. In this study, the nutritional value of chitin and protein and their digestion traits in the carnivorous sundew Drosera capensis L. were estimated using stable nitrogen isotope abundance. Plants fed on chitin derived 49% of the leaf nitrogen from chitin, while those fed on the protein bovine serum albumin (BSA) derived 70% of its leaf nitrogen from this. Moreover, leaf nitrogen content doubled in protein-fed in comparison to chitin-fed plants indicating that the proteins were digested more effectively in comparison to chitin and resulted in significantly higher chlorophyll contents. The surplus chlorophyll and absorbed nitrogen from the protein digestion were incorporated into photosynthetic proteins - the light harvesting antennae of photosystem II. The incorporation of insect nitrogen into the plant photosynthetic apparatus may explain the increased rate of photosynthesis and plant growth after feeding. This general response in many genera of carnivorous plants has been reported in many previous studies. PMID:26998942

  19. Effects of Chitin Whiskers on Physical Properties and Osteoblast Culture of Alginate Based Nanocomposite Hydrogels.

    Science.gov (United States)

    Huang, Yao; Yao, Mengyu; Zheng, Xing; Liang, Xichao; Su, Xiaojuan; Zhang, Yu; Lu, Ang; Zhang, Lina

    2015-11-01

    Novel nanocomposite hydrogels composed of polyelectrolytes alginate and chitin whiskers with biocompatibility were successfully fabricated based on the pH-induced charge shifting behavior of chitin whiskers. The chitin whiskers with mean length and width of 300 and 20 nm were uniformly dispersed in negatively charged sodium alginate aqueous solution, leading to the formation of the homogeneous nanocomposite hydrogels. The experimental results indicated that their mechanical properties were significantly improved compared to alginate hydrogel and the swelling trends were inhibited as a result of the strong electrostatic interactions between the chitin whiskers and alginate. The nanocomposite hydrogels exhibited certain crystallinity and hierarchical structure with nanoscale chitin whiskers, similar to the structure of the native extracellular matrix. Moreover, the nanocomposite hydrogels were successfully applied as bone scaffolds for MC3T3-E1 osteoblast cells, showing their excellent biocompatibility and low cytotoxicity. The results of fluorescent micrographs and scanning electronic microscope (SEM) images revealed that the addition of chitin whiskers into the nanocomposite hydrogels markedly promoted the cell adhesion and proliferation of the osteoblast cells. The biocompatible nanocomposite hydrogels have potential application in bone tissue engineering.

  20. Synthesis and utilization of chitin humic acid hybrid as sorbent for Cr(III)

    Science.gov (United States)

    Santosa, Sri Juari; Siswanta, Dwi; Sudiono, Sri; Sehol, Muhamad

    2007-11-01

    New types of hybrid material have been synthesized by using four different methods of immobilization of humic acid (HA) on chitin. The most stable hybrid material toward the change of medium acidity was then utilized as sorbent for Cr(III). The HA was extracted from peat soil of Gambut District, South Kalimantan, Indonesia, using the recommended procedure of International Humic Substances Society (IHSS), while the chitin was isolated from crab shell waste through deproteination using 3.5% (w/v) NaOH and followed by removal of inorganic impurities using 1 M HCl. The four methods of immobilization of HA on chitin were (i) Method A: chitin powder (4 g) was gently poured into the stirred solution of 0.4 g HA in 40 mL of 0.01 M NaOH. After overnight stirring, the solid was separated, washed with water, and dried in oven at 70 °C. (ii) Method B: gelatinous chitin (40 g) in 250 mL of 0.5 M HCl was reacted with HA (4 g) in 500 mL of 0.5 M NaOH and aged for 24 h. The product was washed with water and dried. (iii) Method C: HA powder (0.5 g) was mixed with the stirred gel of chitin (2.5 g) in 60 mL of CaCl 2 saturated methanol and the mixture was then washed with the mixed solution of 25 mL of 2 M sodium citrate and ethylene glycol 1:1. The solid was separated, washed with water, and dried. (iv) Method D: the solution of HA (0.056 g) in 10 mL of 0.01 M NaOH was reacted with the gel of chitin (0.2 g) in 10 mL of CaCl 2 saturated methanol. After 24 h stirring, the solid was separated from the reaction medium, washed with the mixed solution of 2 M sodium citrate and ethylene glycol 1:1, and followed by washing with water and drying. Parameters investigated in this study consisted of the stability test of the immobilized HA, as well as the rate constant ( k1), capacity ( b), and energy ( E) of sorption as well as the rate constant of desorption ( k-1). The k1 and k-1 were determined according to a kinetic model of first order sorption reaching equilibrium, while the b and E

  1. The functions Of LysM Proteins And Chitin Tetra-Saccarides Signaling Pathway in Zebrafish Embryos

    DEFF Research Database (Denmark)

    Laroche, Fabrice Jean Francois

    and studied their roles – at the cellular level and during zebrafish development. To improve the experimental methods, he developed nanotechnological strategies to genetically modify human embryonic kidney cells and zebrafish. The PhD degree was completed at the Department of Molecular Biology and Genetics......Chitin is an ancient organic bio-polymer, found in abundance on land and at sea. However, knowledge on chitin functions in animals is lacking. In his research project, Fabrice Laroche studied responses to chitin in zebrafish embryos, and he described chitin signalling pathways. Proteins related...... to chitin responses are increasingly being associated with human diseases. Recently, several lysin motif (LysM)-containing proteins were highlighted for their molecular affinity to chitin-like compounds. Addressing these matters, Fabrice Laroche identified zebrafish and human lysin motif-encoding genes...

  2. Effect of hydrolysis on heat capacity, thermodynamic functions, and the relaxation transition of crab chitin and chitosan

    Science.gov (United States)

    Kashtanov, E. A.; Uryash, V. F.; Kokurina, N. Yu.; Larina, V. N.

    2014-02-01

    The heat capacity of crab chitin and chitosan is measured in a vacuum adiabatic calorimeter at 10-330 K. The thermodynamic characteristics (enthalpy, entropy, and Gibbs function) are calculated at T → 0 K to 330 K. Differential thermal analysis is used to calculate the relaxation transitions and thermal degradation of chitin and chitosan at 80-600 K. Acid hydrolysis is performed and its effect on the physicochemical properties and thermodynamic functions of chitin and chitosan is studied.

  3. Identification of a Membrane-Bound Transcriptional Regulator That Links Chitin and Natural Competence in Vibrio cholerae

    OpenAIRE

    Dalia, Ankur B.; Lazinski, David W.; Camilli, Andrew

    2014-01-01

    ABSTRACT Vibrio cholerae is naturally competent when grown on chitin. It is known that expression of the major regulator of competence, TfoX, is controlled by chitin; however, the molecular mechanisms underlying this requirement for chitin have remained unclear. In the present study, we identify and characterize a membrane-bound transcriptional regulator that positively regulates the small RNA (sRNA) TfoR, which posttranscriptionally enhances tfoX translation. We show that this regulation of ...

  4. Green Conversion of Agroindustrial Wastes into Chitin and Chitosan by Rhizopus arrhizus and Cunninghamella elegans Strains

    Directory of Open Access Journals (Sweden)

    Lúcia Raquel Ramos Berger

    2014-05-01

    Full Text Available This article sets out a method for producing chitin and chitosan by Cunninghamella elegans and Rhizopus arrhizus strains using a green metabolic conversion of agroindustrial wastes (corn steep liquor and molasses. The physicochemical characteristics of the biopolymers and antimicrobial activity are described. Chitin and chitosan were extracted by alkali-acid treatment, and characterized by infrared spectroscopy, viscosity and X-ray diffraction. The effectiveness of chitosan from C. elegans and R. arrhizus in inhibiting the growth of Listeria monocytogenes, Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella enterica, Escherichia coli and Yersinia enterocolitica were evaluated by determining the minimum inhibitory concentrations (MIC and the minimum bactericidal concentrations (MBC. The highest production of biomass (24.60 g/L, chitin (83.20 mg/g and chitosan (49.31 mg/g was obtained by R. arrhizus. Chitin and chitosan from both fungi showed a similar degree of deacetylation, respectively of 25% and 82%, crystallinity indices of 33.80% and 32.80% for chitin, and 20.30% and 17.80% for chitosan. Both chitin and chitosan presented similar viscosimetry of 3.79–3.40 cP and low molecular weight of 5.08 × 103 and 4.68 × 103 g/mol. They both showed identical MIC and MBC for all bacteria assayed. These results suggest that: agricultural wastes can be produced in an environmentally friendly way; chitin and chitosan can be produced economically; and that chitosan has antimicrobial potential against pathogenic bacteria.

  5. Embryonic desiccation resistance in Aedes aegypti: presumptive role of the chitinized Serosal Cuticle

    Directory of Open Access Journals (Sweden)

    Peixoto Alexandre

    2008-09-01

    Full Text Available Abstract Background One of the major problems concerning dengue transmission is that embryos of its main vector, the mosquito Aedes aegypti, resist desiccation, surviving several months under dry conditions. The serosal cuticle (SC contributes to mosquito egg desiccation resistance, but the kinetics of SC secretion during embryogenesis is unknown. It has been argued that mosquito SC contains chitin as one of its components, however conclusive evidence is still missing. Results We observed an abrupt acquisition of desiccation resistance during Ae. aegypti embryogenesis associated with serosal cuticle secretion, occurring at complete germ band extension, between 11 and 13 hours after egglaying. After SC formation embryos are viable on dry for at least several days. The presence of chitin as one of the SC constituents was confirmed through Calcofluor and WGA labeling and chitin quantitation. The Ae. aegypti Chitin Synthase A gene (AaCHS1 possesses two alternatively spliced variants, AaCHS1a and AaCHS1b, differentially expressed during Ae. aegypti embryonic development. It was verified that at the moment of serosal cuticle formation, AaCHS1a is the sole variant specifically expressed. Conclusion In addition to the peritrophic matrix and exoskeleton, these findings confirm chitin is also present in the mosquito serosal cuticle. They also point to the role of the chitinized SC in the desiccation resistance of Ae. aegypti eggs. AaCHS1a expression would be responsible for SC chitin synthesis. With this embryological approach we expect to shed new light regarding this important physiological process related to the Ae. aegypti life cycle.

  6. Squid Pen Chitin Chitooligomers as Food Colorants Absorbers

    Directory of Open Access Journals (Sweden)

    Tzu-Wen Liang

    2015-01-01

    Full Text Available One of the most promising applications of chitosanase is the conversion of chitinous biowaste into bioactive chitooligomers (COS. TKU033 chitosanase was induced from squid pen powder (SPP-containing Bacillus cereus TKU033 medium and purified by ammonium sulfate precipitation and column chromatography. The enzyme was relatively more thermostable in the presence of the substrate and had an activity of 93% at 50 °C in a pH 5 buffer solution for 60 min. Furthermore, the enzyme used for the COS preparation was also studied. The enzyme products revealed various mixtures of COS that with different degrees of polymerization (DP, ranging from three to nine. In the culture medium, the fermented SPP was recovered, and it displayed a better adsorption rate (up to 96% for the disperse dyes than the water-soluble food colorants, Allura Red AC (R40 and Tartrazne (Y4. Fourier transform-infrared spectroscopic (FT-IR analysis proved that the adsorption of the dyes onto fermented SPP was a physical adsorption. Results also showed that fermented SPP was a favorable adsorber and could be employed as low-cost alternative for dye removal in wastewater treatment.

  7. [Chitin Synthase 2 (CHS2) gene of Malassezia species].

    Science.gov (United States)

    Kano, Rui

    2005-01-01

    Malassezia species have been recognized as members of the microbiological flora of human and animal skin; they are also considered to play an important role in the pathogenesis of folliculitis, atopic dermatitis and otitis externa. Therefore, the molecular characteristics were investigated to clarify the epidemiology and the pathogenesis of diseases associated with Malassezia species in human and animals. Molecular investigation was made of 105 clinical isolates of M. pachydermatis from dogs and cats by random amplification of polymorphic DNA (RAPD) and chitin synthase 2 (CHS2) gene sequence analyses. The RAPD analysis and CHS2 gene analysis indicated that clinical isolates of M. pachydermatis were divided into four distinct genetic types (A, B, C and D). Type A was isolated from lesions of atopic dermatitis, flea allergic dermatitis, otitis externa, pyoderma and seborrheic (dermatitidis) in dogs and cats, and might be predominant on this. The phylogenetic analysis of the nucleotide sequences of CHS2 gene fragments of standard strains of 11 Malassezia species showed 11 distinct clusters of this species. PMID:16094288

  8. Chitosan-chitin nanocrystal composite scaffolds for tissue engineering.

    Science.gov (United States)

    Liu, Mingxian; Zheng, Huanjun; Chen, Juan; Li, Shuangli; Huang, Jianfang; Zhou, Changren

    2016-11-01

    Chitin nanocrystals (CNCs) with length and width of 300 and 20nm were uniformly dispersed in chitosan (CS) solution. The CS/CNCs composite scaffolds prepared utilizing a dispersion-based freeze dry approach exhibit significant enhancement in compressive strength and modulus compared with pure CS scaffold both in dry and wet state. A well-interconnected porous structure with size in the range of 100-200μm and over 80% porosity are found in the composite scaffolds. The crystal structure of CNCs is retained in the composite scaffolds. The incorporation of CNCs leads to increase in the scaffold density and decrease in the water swelling ratio. Moreover, the composite scaffolds are successfully applied as scaffolds for MC3T3-E1 osteoblast cells, showing their excellent biocompatibility and low cytotoxicity. The results of fluorescent micrographs images reveal that CNCs can markedly promote the cell adhesion and proliferation of the osteoblast on CS. The biocompatible composite scaffolds with enhanced mechanical properties have potential application in bone tissue engineering. PMID:27516335

  9. Chitin Fiber and Chitosan 3D Composite Rods

    Directory of Open Access Journals (Sweden)

    Zhengke Wang

    2010-01-01

    Full Text Available Chitin fiber (CHF and chitosan (CS 3D composite rods with layer-by-layer structure were constructed by in situ precipitation method. CHF could not be dissolved in acetic acid aqueous solution, but CS could be dissolved due to the different deacetylation degree (D.D between CHF and CS. CHF with undulate surfaces could be observed using SEM to demonstrate that the sufficiently rough surfaces and edges of the fiber could enhance the mechanical combining stress between fiber and matrix. XRD indicated that the crystallinity of CHF/CS composites decreased and CS crystal plane d-spacing of CHF/CS composites became larger than that of pure CS rod. TG analysis showed that mixing a little amount of CHF could enhance thermal stability of CS rod, but when the content of CHF was higher than the optimum amount, its thermal stability decreased. When 0.5% CHF was added into CS matrix, the bending strength and bending modulus of the composite rods arrived at 114.2 MPa and 5.2 GPa, respectively, increased by 23.6% and 26.8% compared with pure CS rods, indicating that CHF/CS composite rods could be a better candidate for bone fracture internal fixation.

  10. Analysis of chitin-binding proteins from Manduca sexta provides new insights into evolution of peritrophin A-type chitin-binding domains in insects.

    Science.gov (United States)

    Tetreau, Guillaume; Dittmer, Neal T; Cao, Xiaolong; Agrawal, Sinu; Chen, Yun-Ru; Muthukrishnan, Subbaratnam; Haobo, Jiang; Blissard, Gary W; Kanost, Michael R; Wang, Ping

    2015-07-01

    In insects, chitin is a major structural component of the cuticle and the peritrophic membrane (PM). In nature, chitin is always associated with proteins among which chitin-binding proteins (CBPs) are the most important for forming, maintaining and regulating the functions of these extracellular structures. In this study, a genome-wide search for genes encoding proteins with ChtBD2-type (peritrophin A-type) chitin-binding domains (CBDs) was conducted. A total of 53 genes encoding 56 CBPs were identified, including 15 CPAP1s (cuticular proteins analogous to peritrophins with 1 CBD), 11 CPAP3s (CPAPs with 3 CBDs) and 17 PMPs (PM proteins) with a variable number of CBDs, which are structural components of cuticle or of the PM. CBDs were also identified in enzymes of chitin metabolism including 6 chitinases and 7 chitin deacetylases encoded by 6 and 5 genes, respectively. RNA-seq analysis confirmed that PMP and CPAP genes have differential spatial expression patterns. The expression of PMP genes is midgut-specific, while CPAP genes are widely expressed in different cuticle forming tissues. Phylogenetic analysis of CBDs of proteins in insects belonging to different orders revealed that CPAP1s from different species constitute a separate family with 16 different groups, including 6 new groups identified in this study. The CPAP3s are clustered into a separate family of 7 groups present in all insect orders. Altogether, they reveal that duplication events of CBDs in CPAP1s and CPAP3s occurred prior to the evolutionary radiation of insect species. In contrast to the CPAPs, all CBDs from individual PMPs are generally clustered and distinct from other PMPs in the same species in phylogenetic analyses, indicating that the duplication of CBDs in each of these PMPs occurred after divergence of insect species. Phylogenetic analysis of these three CBP families showed that the CBDs in CPAP1s form a clearly separate family, while those found in PMPs and CPAP3s were clustered

  11. Extreme biomimetic approach for developing novel chitin-GeO2 nanocomposites with photoluminescent properties

    Institute of Scientific and Technical Information of China (English)

    Marcin Wysokowski[1; Mykhailo Motylenko[2; Jan Beyer[3; Anna Makarova[4; Hartmut Stocker[5; Juliane Walter[5; Roberta Galli[6; Sabine Kaiser[5; Denis Vyalikh[4,7; Vasilii V. Bazhenov[5; laroslav Petrenko[5; Allison L Stelling[8; Serguei L. Molodtsovs[5,9,10; Dawid Stawski[11; Krzysztof J.Kurzydfowski[12; Enrico Langer[13; Mikhail V Tsurkan[14; Teofil Jesionowski[1; Johannes Heitmann[3; Dirk C. Meyer[5; Hermann Ehrlich[5

    2015-01-01

    This work presents an extreme biomimetics route for the creation of nano- structured biocomposites utilizing a chitinous template of poriferan origin. The specific thermal stability of the nanostructured chitinous template allowed for the formation under hydrothermal conditions of a novel germanium oxide- chitin composite with a defined nanoscale structure. Using a variety of analytical techniques (FTIR, Raman, energy dispersive X-ray (EDX), near-edge X-ray absorption fine structure (NEXAFS), and photoluminescence (PL) spectroscopy, EDS-mapping, selected area for the electron diffraction pattern (SAEDP), and transmission electron microscopy (TEM)), we showed that this bioorganic scaffold induces the growth of GeO2 nanocrystals with a narrow (150-300 nm) size distri- bution and predominantly hexagonal phase, demonstrating the chitin template's control over the crystal morphology. The formed GeO2-chitin composite showed several specific physical properties, such as a striking enhancement in photo- luminescence exceeding values previously reported in GeOR-based biomaterials. These data demonstrate the potential of extreme biomimetics for developing new-generation nanostructured materials.

  12. Bacterial chitinolytic communities respond to chitin and pH alteration in soil

    DEFF Research Database (Denmark)

    Kielak, Anna; Cretoiu, Mariana; Semenov, Alexander;

    2013-01-01

    in moderately acid soil in which the level of chitin, next to the pH, was altered. Examination of chitinase activities revealed fast responses to the added crude chitin, with peaks of enzymatic activity occurring on day 7. PCR-denaturing gradient gel electrophoresis (DGGE)-based analyses of 16S rRNA and chi......A genes showed structural changes of the phylogenetically and functionally based bacterial communities following chitin addition and pH alteration. Pyrosequencing analysis indicated (i) that the diversity of chiA gene types in soil is enormous and (i) that different chiA gene types are selected...... by the addition of chitin at different prevailing soil pH values. Interestingly, a major role of Gram-negative bacteria versus a minor one of Actinobacteria in the immediate response to the added chitin (based on 16S rRNA gene abundance and chiA gene types) was indicated. The results of this study enhance our...

  13. Characterization of a Chitin-Binding Protein from Bacillus thuringiensis HD-1.

    Directory of Open Access Journals (Sweden)

    Naresh Arora

    Full Text Available Strains of Bacillus thuringiensis produce insecticidal proteins. These strains have been isolated from diverse ecological niches, such as soil, phylloplane, insect cadavers and grain dust. To effectively propagate, these strains produce a range of molecules that facilitate its multiplication in a competing environment. In this report, we have examined synthesis of a chitin-binding protein and evaluated its effect on fungi encountered in environment and its interaction with insecticidal proteins synthesized by B. thuringiensis. The gene encoding chitin-binding protein has been cloned and expressed. The purified protein has been demonstrated to interact with Cry insecticidal protein, Cry1Ac by Circular Dichrosim spectroscopy (CD and in vitro pull down assays. The chitin-binding protein potentiates insecticidal activity of bacillar insecticidal protein, Cry1Ac. Further, chitin-binding protein was fungistatic against several soil fungi. The chitin binding protein is expressed in spore mother cell and deposited along with insecticidal protein, Cry1Ac. It interacts with Cry1Ac to potentiate its insecticidal activity and facilitate propagation of Bacillus strain in environment by inhibiting growth of certain fungi.

  14. Chitin synthetases in Candida albicans: a review on their subcellular distribution and biological function.

    Science.gov (United States)

    Martínez, J P; Gozalbo, D

    1994-09-01

    In the light of recent genetic advances, some results regarding chitin biosynthetic activities are reviewed in this paper. Genes coding for distinct enzymes displaying chitin synthetase activities have been characterized in Saccharomyces cerevisiae as well as in other fungal species including Candida albicans. Several activities seem to exist in the cells: (i) one zymogenic, located in cytoplasmic vesicles called chitosomes, although the presence of other types of vesicles with zymogenic activity cannot be completely discarded, and (ii) plasma membrane associated activities (the active enzyme and probably two distinct pools of zymogenic activity). Possible relationships between these activities, if any, remain to be determined. These multiplicity of enzymes is not surprising taking into account that chitin biosynthesis is required during very well defined temporal and spatial events of the cell cycle. A general repair function for one of the chitin biosynthetic activities is proposed as a possible salvage mechanism to warrant cell survival after wall damage has been caused, since chitin appears to be the most suitable polymer to carry out this function due to its particular physico-chemical properties.

  15. Modification of Chitin with Kraft Lignin and Development of New Biosorbents for Removal of Cadmium(II and Nickel(II Ions

    Directory of Open Access Journals (Sweden)

    Marcin Wysokowski

    2014-04-01

    Full Text Available Novel, functional materials based on chitin of marine origin and lignin were prepared. The synthesized materials were subjected to physicochemical, dispersive-morphological and electrokinetic analysis. The results confirm the effectiveness of the proposed method of synthesis of functional chitin/lignin materials. Mechanism of chitin modification by lignin is based on formation of hydrogen bonds between chitin and lignin. Additionally, the chitin/lignin materials were studied from the perspective of waste water treatment. The synthetic method presented in this work shows an attractive and facile route for producing low-cost chitin/lignin biosorbents with high efficiency of nickel and cadmium adsorption (88.0% and 98.4%, respectively. The discovery of this facile method of synthesis of functional chitin/lignin materials will also have a significant impact on the problematic issue of the utilization of chitinous waste from the seafood industry, as well as lignin by-products from the pulp and paper industry.

  16. Chitin Amendment Increases Soil Suppressiveness toward Plant Pathogens and Modulates the Actinobacterial and Oxalobacteraceal Communities in an Experimental Agricultural Field

    NARCIS (Netherlands)

    Cretoiu, Mariana Silvia; Korthals, Gerard W.; Visser, Johnny H. M.; van Elsas, Jan Dirk

    2013-01-01

    A long-term experiment on the effect of chitin addition to soil on the suppression of soilborne pathogens was set up and monitored for 8 years in an experimental field, Vredepeel, The Netherlands. Chitinous matter obtained from shrimps was added to soil top layers on two different occasions, and the

  17. Effects of Chitin and Its Derivative Chitosan on Postharvest Decay of Fruits: A Review

    Directory of Open Access Journals (Sweden)

    Weimin Liu

    2011-01-01

    Full Text Available Considerable economic losses to harvested fruits are caused by postharvest fungal decay during transportation and storage, which can be significantly controlled by synthetic fungicides. However, considering public concern over pesticide residues in food and the environment, there is a need for safer alternatives for the control of postharvest decay to substitute synthetic fungicides. As the second most abundant biopolymer renewable source in nature, chitin and its derivative chitosan are widely used in controlling postharvest decay of fruits. This review aims to introduce the effect of chitin and chitosan on postharvest decay in fruits and the possible modes of action involved. We found most of the actions discussed in these researches rest on physiological mechanisms. All of the mechanisms are summarized to lay the groundwork for further studies which should focus on the molecular mechanisms of chitin and chitosan in controlling postharvest decay of fruits.

  18. Bridging peripheral nerves using a deacetyl chitin conduit combined with short-term electrical stimulation

    Institute of Scientific and Technical Information of China (English)

    Zhongli Zhang; Xin Li; Songjie Zuo; Jie Xin; Peixun Zhang

    2014-01-01

    Previous studies have demonstrated that deacetyl chitin conduit nerve bridging or electrical stimulation can effectively promote the regeneration of the injured peripheral nerve. We hypoth-esized that the combination of these two approaches could result in enhanced regeneration. Rats with right sciatic nerve injury were subjected to deacetyl chitin conduit bridging combined with electrical stimulation (0.1 ms, 3 V, 20 Hz, for 1 hour). At 6 and 12 weeks after treatment, nerve conduction velocity, myelinated axon number, ifber diameter, axon diameter and the thickness of the myelin sheath in the stimulation group were better than in the non-stimulation group. The results indicate that deacetyl chitin conduit bridging combined with temporary electrical stimu-lation can promote peripheral nerve repair.

  19. Bridging peripheral nerves using a deacetyl chitin conduit combined with short-term electrical stimulation.

    Science.gov (United States)

    Zhang, Zhongli; Li, Xin; Zuo, Songjie; Xin, Jie; Zhang, Peixun

    2014-05-15

    Previous studies have demonstrated that deacetyl chitin conduit nerve bridging or electrical stimulation can effectively promote the regeneration of the injured peripheral nerve. We hypothesized that the combination of these two approaches could result in enhanced regeneration. Rats with right sciatic nerve injury were subjected to deacetyl chitin conduit bridging combined with electrical stimulation (0.1 ms, 3 V, 20 Hz, for 1 hour). At 6 and 12 weeks after treatment, nerve conduction velocity, myelinated axon number, fiber diameter, axon diameter and the thickness of the myelin sheath in the stimulation group were better than in the non-stimulation group. The results indicate that deacetyl chitin conduit bridging combined with temporary electrical stimulation can promote peripheral nerve repair. PMID:25206762

  20. Cytotoxicity and mechanical behavior of chitin-bentonite clay based polyurethane bio-nanocomposites.

    Science.gov (United States)

    Zia, Khalid Mahmood; Zuber, Mohammad; Barikani, Mehdi; Hussain, Rizwan; Jamil, Tahir; Anjum, Sohail

    2011-12-01

    Chitin based polyurethane bio-nanocomposites (PUBNC) were prepared using chitin, Delite HPS bentonite nanoclay enriched in montmorillonite (MMT), 4,4'-diphenylmethane diisocyanate (MDI) and polycaprolactone polyol CAPA 231 (3000 g/mol(-1)). The prepolymers having different concentration of Delite HPS bentonite nanoclay were extended with 2 moles of chitin. The structures of the resulted polymers were determined by FT-IR technique. The effect of nanoclay contents on mechanical properties and in vitro biocompatibility was investigated. The mechanical properties of the synthesized materials were improved with increase in the Delite HPS bentonite nanoclay contents. Optimum mechanical properties were obtained from the PU bio-nanocomposite samples having 4% Delite HPS bentonite nanoclay. The results revealed that the final PU bio-nanocomposite having 2% Delite HPS bentonite nanoclay contents is ideal contenders for surgical threads with on going investigations into their in vitro biocompatibility, non-toxicity, and mechanical properties. PMID:21945787

  1. AFM PeakForce QNM mode: Evidencing nanometre-scale mechanical properties of chitin-silica hybrid nanocomposites.

    Science.gov (United States)

    Smolyakov, G; Pruvost, S; Cardoso, L; Alonso, B; Belamie, E; Duchet-Rumeau, J

    2016-10-20

    PeakForce Quantitative Nanomechanical Mapping (QNM) AFM mode was used to explore the mechanical properties of textured chitin-silica hybrid films at the nanoscale. The influence of the force applied by the tip on the sample surface was studied for standard homogeneous samples, for chitin nanorods and for chitin-silica hybrid nanocomposites. Thick films of superimposed chitin nanorods showed a monotonous increase of DMT modulus (based on the Derjaguin-Muller-Toporov model) owing to an increase in modulus at the interface between nanorods due to geometrical constraints of the AFM acquisition. A similar variation of DMT modulus was obtained for chitin-silica hybrid thick films related to mechanical strengthening induced by the presence of silica. This work revealed the role of the organic-inorganic interface, at the nanoscale, in the mechanical behaviour of textured materials using PeakForce QNM mode, with optimized analysis conditions. PMID:27474579

  2. Characterization of a Chitin Synthase Encoding Gene and Effect of Diflubenzuron in Soybean Aphid, Aphis Glycines

    Directory of Open Access Journals (Sweden)

    Raman Bansal, M. A. Rouf Mian, Omprakash Mittapalli, Andy P. Michel

    2012-01-01

    Full Text Available Chitin synthases are critical enzymes for synthesis of chitin and thus for subsequent growth and development in insects. We identified the cDNA of chitin synthase gene (CHS in Aphis glycines, the soybean aphid, which is a serious pest of soybean. The full-length cDNA of CHS in A. glycines (AyCHS was 5802 bp long with an open reading frame of 4704 bp that encoded for a 1567 amino acid residues protein. The predicted AyCHS protein had a molecular mass of 180.05 kDa and its amino acid sequence contained all the signature motifs (EDR, QRRRW and TWGTR of chitin synthases. The quantitative real-time PCR (qPCR analysis revealed that AyCHS was expressed in all major tissues (gut, fat body and integument; however, it had the highest expression in integument (~3.5 fold compared to gut. Interestingly, the expression of AyCHS in developing embryos was nearly 7 fold higher compared to adult integument, which probably is a reflection of embryonic molts in hemimetabolus insects. Expression analysis in different developmental stages of A. glycines revealed a consistent AyCHS expression in all stages. Further, through leaf dip bioassay, we tested the effect of diflubenzuron (DFB, Dimilin ®, a chitin-synthesis inhibitor, on A. glycines' survival, fecundity and body weight. When fed with soybean leaves previously dipped in 50 ppm DFB solution, A. glycines nymphs suffered significantly higher mortality compared to control. A. glycines nymphs feeding on diflubenzuron treated leaves showed a slightly enhanced expression (1.67 fold of AyCHS compared to nymphs on untreated leaves. We discussed the potential applications of the current study to develop novel management strategies using chitin-synthesis inhibitors and using RNAi by knocking down AyCHS expression.

  3. Micro-CT imaging of denatured chitin by silver to explore honey bee and insect pathologies.

    Directory of Open Access Journals (Sweden)

    Peter R Butzloff

    Full Text Available BACKGROUND: Chitin and cuticle coatings are important to the environmental and immune defense of honey bees and insect pollinators. Pesticides or environmental effects may target the biochemistry of insect chitin and cuticle coating. Denaturing of chitin involves a combination of deacetylation, intercalation, oxidation, Schweiger-peeling, and the formation of amine hydrochloride salt. The term "denatured chitin" calls attention to structural and property changes to the internal membranes and external carapace of organisms so that some properties affecting biological activities are diminished. METHODOLOGY/PRINCIPAL FINDINGS: A case study was performed on honey bees using silver staining and microscopic computer-tomographic x-ray radiography (micro-CT. Silver nitrate formed counter-ion complexes with labile ammonium cations and reacted with amine hydrochloride. Silver was concentrated in the peritrophic membrane, on the abdomen, in the glossa, at intersegmental joints (tarsi, at wing attachments, and in tracheal air sacs. Imaged mono-esters and fatty acids from cuticle coating on external surfaces were apparently reduced by an alcohol pretreatment. CONCLUSIONS/SIGNIFICANCE: The technique provides 3-dimensional and sectional images of individual honey bees consistent with the chemistries of silver reaction and complex formation with denatured chitin. Environmental exposures and influences such as gaseous nitric oxide intercalant, trace oxidants such as ozone gas, oligosachharide salt conversion, exposure to acid rain, and chemical or biochemical denaturing by pesticides may be studied using this technique. Peritrophic membranes, which protect against food abrasion, microorganisms, and permit efficient digestion, were imaged. Apparent surface damage to the corneal lenses of compound eyes by dilute acid exposure consistent with chitin amine hydrochloride formation was imaged. The technique can contribute to existing insect pathology research, and may

  4. Expression in E. coli and characterization of the catalytic domain of Botrytis cinerea chitin synthase

    Directory of Open Access Journals (Sweden)

    Piffeteau Annie

    2010-11-01

    Full Text Available Abstract Background Chitin synthase 3a (CHS3a from Botrytis cinerea (Bc catalyses the multiple transfer of N-acetylglucosamine (GlcNAc residues to the growing chitin chain. Chitin, a β-1,4 linked GlcNAc homopolymer, is an essential cell wall component of filamentous fungi. Chitin synthase, processive membranous protein, has been recognized as a promising target for new antifungicides. Enzymatic characterizations of chitin synthases have been limited, mainly because purity and amounts of integral enzyme obtained after purification procedures have not been sufficient. Findings We undertook the preparation of two BcCHS3a fragment proteins, containing only the central domain and devoid of the N-terminal and transmembrane C-terminal regions. The central domain of CHS3a, named SGC (Spsa GntI Core, is conserved in all UDP-glycosyltransferases and it is believed to contain the active site of the enzyme. CHS3a-SGC protein was totally expressed as inclusion bodies in Escherichia coli. We performed recombinant CHS3a-SGC purification in denaturing conditions, followed by a refolding step. Although circular dichroism spectra clearly exhibited secondary structures of renatured CHS3a-SGC, no chitin synthase activity was detected. Nevertheless CHS3a-SGC proteins show specific binding for the substrate UDP-GlcNAc with a dissociation constant similar to the Michaelis constant and a major contribution of the uracil moiety for recognition was confirmed. Conclusions Milligram-scale quantities of CHS3a-SGC protein with native-like properties such as specific substrate UDP-GlcNAc binding could be easily obtained. These results are encouraging for subsequent heterologous expression of full-length CHS3a.

  5. Unique posttranslational modifications of chitin-binding lectins of Entamoeba invadens cyst walls.

    Science.gov (United States)

    Van Dellen, Katrina L; Chatterjee, Anirban; Ratner, Daniel M; Magnelli, Paula E; Cipollo, John F; Steffen, Martin; Robbins, Phillips W; Samuelson, John

    2006-05-01

    Entamoeba histolytica, which causes amebic dysentery and liver abscesses, is spread via chitin-walled cysts. The most abundant protein in the cyst wall of Entamoeba invadens, a model for amebic encystation, is a lectin called EiJacob1. EiJacob1 has five tandemly arrayed, six-Cys chitin-binding domains separated by low-complexity Ser- and Thr-rich spacers. E. histolytica also has numerous predicted Jessie lectins and chitinases, which contain a single, N-terminal eight-Cys chitin-binding domain. We hypothesized that E. invadens cyst walls are composed entirely of proteins with six-Cys or eight-Cys chitin-binding domains and that some of these proteins contain sugars. E. invadens genomic sequences predicted seven Jacob lectins, five Jessie lectins, and three chitinases. Reverse transcription-PCR analysis showed that mRNAs encoding Jacobs, Jessies, and chitinases are increased during E. invadens encystation, while mass spectrometry showed that the cyst wall is composed of an approximately 30:70 mix of Jacob lectins (cross-linking proteins) and Jessie and chitinase lectins (possible enzymes). Three Jacob lectins were cleaved prior to Lys at conserved sites (e.g., TPSVDK) in the Ser- and Thr-rich spacers between chitin-binding domains. A model peptide was cleaved at the same site by papain and E. invadens Cys proteases, suggesting that the latter cleave Jacob lectins in vivo. Some Jacob lectins had O-phosphodiester-linked carbohydrates, which were one to seven hexoses long and had deoxysugars at reducing ends. We concluded that the major protein components of the E. invadens cyst wall all contain chitin-binding domains (chitinases, Jessie lectins, and Jacob lectins) and that the Jacob lectins are differentially modified by site-specific Cys proteases and O-phosphodiester-linked glycans.

  6. Lipo-chitin oligosaccharides, plant symbiosis signalling molecules that modulate mammalian angiogenesis in vitro.

    Directory of Open Access Journals (Sweden)

    Michael A Djordjevic

    Full Text Available Lipochitin oligosaccharides (LCOs are signaling molecules required by ecologically and agronomically important bacteria and fungi to establish symbioses with diverse land plants. In plants, oligo-chitins and LCOs can differentially interact with different lysin motif (LysM receptors and affect innate immunity responses or symbiosis-related pathways. In animals, oligo-chitins also induce innate immunity and other physiological responses but LCO recognition has not been demonstrated. Here LCO and LCO-like compounds are shown to be biologically active in mammals in a structure dependent way through the modulation of angiogenesis, a tightly-regulated process involving the induction and growth of new blood vessels from existing vessels. The testing of 24 LCO, LCO-like or oligo-chitin compounds resulted in structure-dependent effects on angiogenesis in vitro leading to promotion, or inhibition or nil effects. Like plants, the mammalian LCO biological activity depended upon the presence and type of terminal substitutions. Un-substituted oligo-chitins of similar chain lengths were unable to modulate angiogenesis indicating that mammalian cells, like plant cells, can distinguish between LCOs and un-substituted oligo-chitins. The cellular mode-of-action of the biologically active LCOs in mammals was determined. The stimulation or inhibition of endothelial cell adhesion to vitronectin or fibronectin correlated with their pro- or anti-angiogenic activity. Importantly, novel and more easily synthesised LCO-like disaccharide molecules were also biologically active and de-acetylated chitobiose was shown to be the primary structural basis of recognition. Given this, simpler chitin disaccharides derivatives based on the structure of biologically active LCOs were synthesised and purified and these showed biological activity in mammalian cells. Since important chronic disease states are linked to either insufficient or excessive angiogenesis, LCO and LCO

  7. Management of Plant-parasitic Nematodes with a Chitin-Urea Soil Amendment and Other Materials

    OpenAIRE

    Westerdahl, B. B.; Carlson, H. L.; Grant, J; Radewald, J. D.; Welch, N.; Anderson, C A; Darso, J.; Kirby, D.; Shibuya, F.

    1992-01-01

    Field trials were conducted with a chitin-urea soil amendment and several other nematicides on four crop-nematode combinations: tomato-Meloidogyne incognita; potato-Meloidogyne chitwoodi; walnut-Pratylenchus vulnus; and brussels sprouts-Heterodera schachtii. Significant (P ≤ 0.10) nematode population reductions were obtained with the chitin-urea soil amendment in the trims on potato and walnut. In the trials on brussels sprouts and on tomato, phytotoxicity occurred at rates of 1,868 and 1,093...

  8. Activation of a mitogen-activated protein kinase pathway in Arabidopsis by chitin.

    Science.gov (United States)

    Wan, Jinrong; Zhang, Shuqun; Stacey, Gary

    2004-03-01

    SUMMARY Chitin, a polysaccharide composed of beta-1-->4-linked N-acetyl-d-glucosamine, has been shown or implicated as a signal in plant defence and development. However, the key components of chitin perception and downstream signalling in non-leguminous plants are largely unknown. In recent years, mitogen-activated protein kinases (MAPKs) and their cascades were shown to transduce various extracellular stimuli into internal cellular responses. To investigate the possible involvement of MAPKs in chitin signalling in plants, the model plant Arabidopsis thaliana was treated with crab-shell chitin and also with the purified chitin oligomers (degree of polymerization, d.p. = 2-8). Both mRNA levels and kinase activity of two MAPK genes, AtMPK6 and AtMPK3, were monitored after treatment. The mRNA of AtMPK3 was strongly up-regulated by both chitin and its larger oligomers (d.p. = 6-8), but the mRNA of AtMPK6 did not appear to be regulated by these treatments. However, the kinase activity of both MAPKs was induced by chitin and the larger oligomers (d.p. = 6-8), with AtMPK6 much more strongly induced. In addition, WRKY22, WRKY29, WRKY33 and WRKY53, which encode four WRKY transcription factors that recognize TTGAC(C/T) W-box elements in promoters of numerous plant defence-related genes, were up-regulated by these treatments. WRKY33 and WRKY53 expression was induced by the transgenic expression of the tobacco MAPKK NtMEK2 active mutant NtMEK2(DD), suggesting a potential role for these WRKY transcription factors in relaying the signal generated from the MAPK cascade to downstream genes. These data suggest that AtMPK6/AtMPK3 and WRKY transcription factors (such as WRKY33 and WRKY53) may be important components of a pathway involved in chitin signalling in Arabidopsis plants.

  9. Cadmium sorption in solution by a chitin: effect of pH; Sorption du cadmium en solution par une chitine: effet du pH

    Energy Technology Data Exchange (ETDEWEB)

    Benguella, B.; Benaissa, H. [Universtie de Tlemcen, Lab. de Materiaux Sorbants et Traitement des Eaux, Dept. de Chimie, Faculte des Sciences, Tlemcen (Algeria)

    2001-07-01

    The pH is an essential factor to take into consideration in the sorption mechanisms of metals: it acts both on the metal speciation in solution and on the chemical behaviour of the surface of the sorbing material, and thus indirectly on the sorption mechanism. The effect of the initial pH of the solution on the cadmium sorption by raw state chitin has been studied in static conditions. The approach used is the determination of the sorption kinetics and equilibria for different values of initial pH (pH < 7-7.5). An increase of the initial pH value of the solution leads to an increase of the cadmium sorption capacity by chitin at the equilibrium. The Langmuir model has revealed to be convenient for a mathematical description of the sorption isotherms obtained. (J.S.)

  10. A Review of the Applications of Chitin and Its Derivatives in Agriculture to Modify Plant-Microbial Interactions and Improve Crop Yields

    Directory of Open Access Journals (Sweden)

    Russell G. Sharp

    2013-11-01

    Full Text Available In recent decades, a greater knowledge of chitin chemistry, and the increased availability of chitin-containing waste materials from the seafood industry, have led to the testing and development of chitin-containing products for a wide variety of applications in the agriculture industry. A number of modes of action have been proposed for how chitin and its derivatives can improve crop yield. In addition to direct effects on plant nutrition and plant growth stimulation, chitin-derived products have also been shown to be toxic to plant pests and pathogens, induce plant defenses and stimulate the growth and activity of beneficial microbes. A repeating theme of the published studies is that chitin-based treatments augment and amplify the action of beneficial chitinolytic microbes. This article reviews the evidence for claims that chitin-based products can improve crop yields and the current understanding of the modes of action with a focus on plant-microbe interactions.

  11. Development of novel chitin/nanosilver composite scaffolds for wound dressing applications.

    Science.gov (United States)

    Madhumathi, K; Sudheesh Kumar, P T; Abhilash, S; Sreeja, V; Tamura, H; Manzoor, K; Nair, S V; Jayakumar, R

    2010-02-01

    Antibiotic resistance of microorganisms is one of the major problems faced in the field of wound care and management resulting in complications like infection and delayed wound healing. Currently a lot of research is focused on developing newer antimicrobials to treat wounds infected with antibiotic resistant microorganisms. Silver has been used as an antimicrobial agent for a long time in the form of metallic silver and silver sulfadiazine ointments. Recently silver nanoparticles have come up as a potent antimicrobial agent and are finding diverse medical applications ranging from silver based dressings to silver coated medical devices. Chitin is a natural biopolymer with properties like biocompatibility and biodegradability. It is widely used as a scaffold for tissue engineering applications. In this work, we developed and characterized novel chitin/nanosilver composite scaffolds for wound healing applications. The antibacterial, blood clotting and cytotoxicity of the prepared composite scaffolds were also studied. These chitin/nanosilver composite scaffolds were found to be bactericidal against S. aureus and E. coli and good blood clotting ability. These results suggested that these chitin/nanosilver composite scaffolds could be used for wound healing applications. PMID:19802687

  12. Tracking developmentally regulated post-synthetic processing of homogalacturonan and chitin using reciprocal oligosaccharide probes

    DEFF Research Database (Denmark)

    Mravec, Jozef; Kračun, Stjepan K.; Rydahl, Maja G.;

    2014-01-01

    is limited by a lack of suitable molecular tools. Here, we report the development of a novel non-immunological approach for producing highly selective reciprocal oligosaccharide-based probes for chitosan (the product of chitin deacetylation) and for demethylesterified homogalacturonan. Specific reciprocal...

  13. Chitin enhances serum IgE in Aspergillus fumigatus induced allergy in mice

    DEFF Research Database (Denmark)

    Dubey, Lalit Kumar; Moeller, Jesper Bonnet; Schlosser, Anders;

    2015-01-01

    Aspergillus fumigatus (A. fumigatus) is a ubiquitous fungus that activates, suppresses or modulates the immune response by changing its cell wall structure and by secreting proteases. In this study, we show that chitin acts as an adjuvant in a murine model of A. fumigatus protease induced allergy...

  14. Papain incorporated chitin dressings for wound debridement sterilized by gamma radiation

    Science.gov (United States)

    Singh, Durgeshwer; Singh, Rita

    2012-11-01

    Wound debridement is essential for the removal of necrotic or nonviable tissue from the wound surface to create an environment conducive to healing. Nonsurgical enzymatic debridement is an attractive method due to its effectiveness and ease of use. Papain is a proteolytic enzyme derived from the fruit of Carica papaya and is capable of breaking down a variety of necrotic tissue substrates. The present study was focused on the use of gamma radiation for sterilization of papain dressing with wound debriding activity. Membranes with papain were prepared using 0.5% chitin in lithium chloride/dimethylacetamide solvent and sterilized by gamma radiation. Fluid absorption capacity of chitin-papain membranes without glycerol was 14.30±6.57% in 6 h. Incorporation of glycerol resulted in significant (ppapain was stable on gamma irradiation at 25-35 kGy. The irradiated chitin-papain membranes were impermeable to different bacterial strains and also exhibited strong bactericidal action against both Gram-positive and Gram-negative bacteria. The fluid handling characteristics and the antimicrobial properties of chitin-papain membranes sterilized by gamma radiation were found suitable for use as wound dressing with debriding activity.

  15. Chitinous palynomorphs and palynodebris representing crustacean exoskeleton remains from sediments of the Banda Sea (Indonesia)

    NARCIS (Netherlands)

    Waveren, van I.M.

    1994-01-01

    Palynological residues from surface sediments in the Banda Sea (Indonesia) are characterised by the presence of chitinous palynomorph types that can be correlated with exoskeletons of crustaceans, notably calanoid copepods. A series of 27 palynomorph types are described and informally categorised. A

  16. Optimization of the methods for extraction of chitin in crab shell and preparation of chitosan

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A combination of both acid and alkali treatments was used to extract chitin from crab shell in this study. Then, a three factors ( NaOH solution concentration, reaction time, reaction temperature) and three levels (35, 45, 55; 2, 6, 10; 70, 105, 140) L9 (34) orthogonal experiment design is further adopted to conduct a de-acetyl treatment to prepare chitosan by considering the viscosity and de-acetyl degree of the chitosan as the main performance indexes. Determination of de-acetyl degree of chitin complys with the procedures given by the reference and the viscosity meter was used for determination of viscosity of chitosan. The results show that the extraction of chitin shall use pulverized crab shell as the raw material and such raw material shall be immersed in 10% HC1 solution for 6 hours and washed with water for one time in every 2 hours, then heated in boiled water for 2 hours by the use of 10% thin NaOH solution. Afterwards, the said material shall be washed with water to become a neutral solution and dried over a stove. When chitin is mixed with 55% NaOH solution in a proportion of 1: 10 (W/V, g/mL) and the reaction takes place at a temperature of 105℃ for 6 hours, chitosan having a de-acetyl percentage of 94% and viscosity of > 200 cps can be available.

  17. Transforming nanostructured chitin from crustacean waste into beneficial health products: a must for our society

    Directory of Open Access Journals (Sweden)

    Morganti P

    2011-12-01

    Full Text Available P Morganti1, G Morganti2, A Morganti3,41Department of Dermatology, Second University of Naples, Naples, Italy; 2Centre of Nanoscience, Mavi Sud s.r.l, Aprilia, Italy; 3Max Planck Institute for Intellectual Property and Competition Law, Munich, Germany; 4Lextray, Milan, ItalyAbstract: Chitin, obtained principally from crustacean waste, is a sugar-like polymer that is available at low cost. It has been shown to be bio- and ecocompatible, and has a very low level of toxicity. Recently, it has become possible to industrially produce pure chitin crystals, named "chitin nanofibrils" (CN for their needle-like shape and nanostructured average size (240 × 5 × 7 nm. Due to their specific chemical and physical characteristics, CN may have a range of industrial applications, from its use in biomedical products and biomimetic cosmetics, to biotextiles and health foods. At present, world offshore disposal of this natural waste material is around 250 billion tons per year. It is an underutilized resource and has the potential to supply a wide range of useful products if suitably recycled, thus contributing to sustainable growth and a greener economy.Keywords: chitin nanofibrils, biomimetic cosmetics, biomedical products, food, nanotechnology, waste

  18. Chitin nanofibers as reinforcing and antimicrobial agents in carboxymethyl cellulose films: Influence of partial deacetylation

    Science.gov (United States)

    The development of edible, environmentally friendly, mechanically strong and antimicrobial biopolymer films for active food packaging has gained considerable interest in recent years. The present work deals with the extraction and deacetylation of chitin nanofibers (ChNFs) from crab shells and their...

  19. Fungal chitin dampens inflammation through IL-10 induction mediated by NOD2 and TLR9 activation

    NARCIS (Netherlands)

    Wagener, J.; Malireddi, R.K.; Lenardon, M.D.; Koberle, M.; Vautier, S.; MacCallum, D.M.; Biedermann, T.; Schaller, M.; Netea, M.G.; Kanneganti, T.D.; Brown, G.D.; Brown, A.J.; Gow, N.A.

    2014-01-01

    Chitin is an essential structural polysaccharide of fungal pathogens and parasites, but its role in human immune responses remains largely unknown. It is the second most abundant polysaccharide in nature after cellulose and its derivatives today are widely used for medical and industrial purposes. W

  20. Potential of chitosan (chemically-modified chitin) for extraction of lead-arsenate contaminated soils

    Science.gov (United States)

    Arsenic (As), phosphorous (P), and lead (Pb) contamination in soils represents a health risk to humans and the environment. Chitosan (poly-N-acetyl glucosamine) is a non-toxic and inexpensive food industry byproduct derived from chitin that has been used as an adsorbent of heavy metals. The object...

  1. The effect of chitin synthesis inhibitors on the development of Brugia malayi in Aedes aegypti.

    Science.gov (United States)

    Mohapatra, R; Ranjit, M R; Dash, A P

    1996-09-01

    Two chitin synthesis inhibitors (CSIs) viz., triflumuron and hexaflumuron interfere++ with the development of Brugia malayi in Aedes aegypti (a black-eyed Liverpool strain). The development of B. malayi was slow in both the treated populations and the infection rate, infectivity rate and L3 load per mosquito decreased significantly (P triflumuron. PMID:8984113

  2. In vitro lipid digestion of chitin nanocrystal stabilized o/w emulsions

    NARCIS (Netherlands)

    Tzoumaki, M.V.; Moschakis, T.; Scholten, E.; Biliaderis, C.G.

    2013-01-01

    Chitin nanocrystals (ChN) have been shown to form stable Pickering emulsions. These oil-in-water emulsions were compared with conventional milk (whey protein isolate, WPI, and sodium caseinate, SCn) protein-stabilized emulsions in terms of their lipid digestion kinetics using an in vitro enzymatic p

  3. The chitin biosynthesis pathway in Entamoeba and the role of glucosamine-6-P isomerase by RNA interference.

    Science.gov (United States)

    Samanta, Sintu Kumar; Ghosh, Sudip K

    2012-11-01

    Entamoeba histolytica, the causative agent of amoebiasis, infects through its cyst form. A thick chitin wall protects the cyst from the harsh environment outside of the body. It is known that chitin is synthesized only during encystation, but the chitin synthesis pathway (CSP) of Entamoeba is not well characterized. In this report, we have identified the genes involved in chitin biosynthesis from the Entamoeba genome database and verified their expression profile at the transcriptional level in encysting Entamoeba invadens. Semi-quantitative RT-PCR (sqRT-PCR) analysis showed that all the chitin pathway genes are entirely absent or transcribed at low levels in trophozoites. The mRNA expression of most of the CSP genes reached their maximum level between 9 and 12h after the in vitro initiation of encystation. Double-stranded RNA-mediated silencing of glucosamine-6-P isomerase (Gln6Pi) reduced chitin synthesis to 62-64%, which indicates that Gln6Pi might be a key enzyme for regulating chitin synthesis in Entamoeba. The study of different enzymes involved in glycogen metabolism revealed that stored glycogen is converted to glucose during encystation. It is clear from the sqRT-PCR analysis that the rate of glycolysis decreases as encystation proceeds. Encystation up-regulates the expression of glycogen phosphorylase, which is responsible for glycogen degradation. The significant decrease in chitin synthesis in encysting cells treated with a specific inhibitor of glycogen phosphorylase indicates that the glucose obtained from the degradation of stored glycogen in trophozoites might be one of the major sources of glucose for chitin synthesis.

  4. Identification of a membrane-bound transcriptional regulator that links chitin and natural competence in Vibrio cholerae.

    Science.gov (United States)

    Dalia, Ankur B; Lazinski, David W; Camilli, Andrew

    2014-01-01

    Vibrio cholerae is naturally competent when grown on chitin. It is known that expression of the major regulator of competence, TfoX, is controlled by chitin; however, the molecular mechanisms underlying this requirement for chitin have remained unclear. In the present study, we identify and characterize a membrane-bound transcriptional regulator that positively regulates the small RNA (sRNA) TfoR, which posttranscriptionally enhances tfoX translation. We show that this regulation of the tfoR promoter is direct by performing electrophoretic mobility shift assays and by heterologous expression of this system in Escherichia coli. This transcriptional regulator was recently identified independently and was named "TfoS" (S. Yamamoto et al., Mol. Microbiol., in press, doi:10.1111/mmi.12462). Using a constitutively active form of TfoS, we demonstrate that the activity of this regulator is sufficient to promote competence in V. cholerae in the absence of chitin. Also, TfoS contains a large periplasmic domain, which we hypothesized interacts with chitin to regulate TfoS activity. In the heterologous host E. coli, we demonstrate that chitin oligosaccharides are sufficient to activate TfoS activity at the tfoR promoter. Collectively, these data characterize TfoS as a novel chitin-sensing transcriptional regulator that represents the direct link between chitin and natural competence in V. cholerae. IMPORTANCE Naturally competent bacteria can take up exogenous DNA from the environment and integrate it into their genome by homologous recombination. This ability to take up exogenous DNA is shared by diverse bacterial species and serves as a mechanism to acquire new genes to enhance the fitness of the organism. Several members of the family Vibrionaceae become naturally competent when grown on chitin; however, a molecular understanding of how chitin activates competence is lacking. Here, we identify a novel membrane-bound transcriptional regulator that is required for natural

  5. Electrochemical study of functionalization on the surface of a chitin/platinum-modified glassy carbon paste electrode.

    Science.gov (United States)

    Sugawara, Kazuharu; Yugami, Asako; Terui, Norifumi; Kuramitz, Hideki

    2009-11-01

    To functionalize chitin surfaces using proteins, we developed a glucose oxidase (GOD)-chitin/platinum-modified glassy carbon paste electrode (GCPE) as a model. In a weakly acidic solution, negatively charged GOD were immobilized by the protonated acetylamide groups on chitin. When the electrode was immersed in a solution containing GOD, the enzyme was readily immobilized due to the electrostatic interaction. In addition, measurements were performed using electrodes made with powders of different sizes because sensor performance depends on the particle sizes of glassy carbon powder. PMID:19907096

  6. Alkali- or acid-induced changes in structure, moisture absorption ability and deacetylating reaction of β-chitin extracted from jumbo squid (Dosidicus gigas) pens.

    Science.gov (United States)

    Jung, Jooyeoun; Zhao, Yanyun

    2014-01-01

    Alkali- or acid-induced structural modifications in β-chitin from squid (Dosidicus gigas, d'Orbigny, 1835) pens and their moisture absorption ability (MAA) and deacetylating reaction were investigated and compared with α-chitin from shrimp shells. β-Chitin was converted into the α-form after 3h in 40% NaOH or 1-3 h in 40% HCl solution, and α-chitin obtained from NaOH treatment had higher MAA than had native α-chitin, due to polymorphic destructions. In contrast, induced α-chitin from acid treatment of β-chitin had few polymorphic modifications, showing no significant change (P>0.05) in MAA. β-Chitin was more susceptible to alkali deacetylation than was α-chitin, and required a lower concentration of NaOH and shorter reaction time. These results demonstrate that alkali- or acid-treated β-chitin retained high susceptibility toward solvents, which in turn resulted in good biological activity of β-chitosan for use as a natural antioxidant and antimicrobial substance or application as edible coatings and films for various food applications. PMID:24444948

  7. Enhanced immune response and resistance to white tail disease in chitin-diet fed freshwater prawn, Macrobrachium rosenbergii

    Directory of Open Access Journals (Sweden)

    B.T. Naveen Kumar

    2015-11-01

    Full Text Available Chitin is one of the natural biopolymer found abundantly in the shells of crustaceans, insects and in cell walls of fungi. In this study, we determined the effect of dietary administration of 0.5, 0.75 and 1% chitin on the immune response and disease resistance in freshwater prawn, challenged against Macrobrachium rosenbergii nodavirus (MrNV and extra small virus (XSV. We observed a significantly enhanced immune response, indicated as higher prophenoloxidase activity and respiratory burst of hemocytes, in 0.75% chitin-diet fed prawns compared to the chitin-free-diet fed prawns. Importantly, the relative percent survival (RPS following challenge with white muscle disease (WTD viruses was found relatively high in M. rosenbergii fed with diet containing 0.75% chitin (63.16%, suggesting an increased resistance to disease susceptibility. These results indicate that the incorporation of chitin in prawn diet would be beneficial in stimulating the immune response and thereby developing resistance against diseases.

  8. Enzymatic production of defined chitosan oligomers with a specific pattern of acetylation using a combination of chitin oligosaccharide deacetylases

    Science.gov (United States)

    Hamer, Stefanie Nicole; Cord-Landwehr, Stefan; Biarnés, Xevi; Planas, Antoni; Waegeman, Hendrik; Moerschbacher, Bruno Maria; Kolkenbrock, Stephan

    2015-03-01

    Chitin and chitosan oligomers have diverse biological activities with potentially valuable applications in fields like medicine, cosmetics, or agriculture. These properties may depend not only on the degrees of polymerization and acetylation, but also on a specific pattern of acetylation (PA) that cannot be controlled when the oligomers are produced by chemical hydrolysis. To determine the influence of the PA on the biological activities, defined chitosan oligomers in sufficient amounts are needed. Chitosan oligomers with specific PA can be produced by enzymatic deacetylation of chitin oligomers, but the diversity is limited by the low number of chitin deacetylases available. We have produced specific chitosan oligomers which are deacetylated at the first two units starting from the non-reducing end by the combined use of two different chitin deacetylases, namely NodB from Rhizobium sp. GRH2 that deacetylates the first unit and COD from Vibrio cholerae that deacetylates the second unit starting from the non-reducing end. Both chitin deacetylases accept the product of each other resulting in production of chitosan oligomers with a novel and defined PA. When extended to further chitin deacetylases, this approach has the potential to yield a large range of novel chitosan oligomers with a fully defined architecture.

  9. Ovicidal activity of chitin synthesis inhibitors when fed to adult German cockroaches (Dictyoptera: Blattellidae).

    Science.gov (United States)

    DeMark, J J; Bennett, G W

    1990-07-01

    Ovicidal activity was observed in four adult groups (virgin males; virgin females; newly gravid females; and inseminated, reproducing females) of the German cockroach, Blattella germanica (L.), fed the chitin synthesis inhibitors triflumuron, chlorfluazuron, hexafluron, and UC 84572 (structure not disclosed) at the LC50's and LC95's determined from fifth-stage nymphs. All compounds were active only when fed to reproducing females (including the feeding period in which the ootheca is developing). Hexafluron and triflumuron at the LC50 caused 100% inhibition of hatch in reproducing females. Chlorfluazuron and UC 84572 at the LC50 had similar ovicidal activity (45.8 and 50.0% hatch, respectively). Female German cockroaches fed the chitin synthesis inhibitors before mating and after the ootheca had protruded from the abdomen were not affected. Reproductive capabilities of males were not affected, and males did not effectively transfer the compounds to untreated females during mating. PMID:2388230

  10. Enzyme-assisted modification of cellulose/chitin fibers with NIPAAm

    OpenAIRE

    IRIMIA, ANAMARIA; CSISZAR, EMILIA; DOBROMIR, MARIUS; Doroftei, Florica; Vasile, Cornelia

    2015-01-01

    Coating processes are applied in order to improve coating adhesion and resistance to degradation. Covalently bound organic coatings rather than merely physically bound ones assure stable modification. In this study a novel two-step process was developed to modify cellulose/chitin mix fibers consisting of enzymatic activation with a commercial cellulase, followed by a coupling reaction with N-isopropylacrylamide (or poly (N-isopropylacrylamide)) in the presence of 1-(3-dimethylaminopropyl)-3-e...

  11. Entamoeba histolytica Lectins Contain Unique 6-Cys or 8-Cys Chitin-Binding Domains

    OpenAIRE

    Van Dellen, Katrina; Ghosh, Sudip K.; Robbins, Phillips W.; Loftus, Brendan; Samuelson, John

    2002-01-01

    The Jacob lectin, the most abundant glycoprotein in the cyst wall of Entamoeba invadens, contains five unique 6-Cys chitin-binding domains (CBDs). We identified Entamoeba histolytica and Entamoeba dispar genes encoding Jacob homologues, each of which contains two predicted 6-Cys CBDs. A unique 8-Cys CBD was found at the N termini of the E. histolytica chitinase and three other predicted lectins, called Jessie 1 to Jessie 3. The CBDs of four E. histolytica lectins (Jacob, chitinase, and Jessie...

  12. Chitin-Lignin Material as a Novel Matrix for Enzyme Immobilization

    OpenAIRE

    Jakub Zdarta; Łukasz Klapiszewski; Marcin Wysokowski; Małgorzata Norman; Agnieszka Kołodziejczak-Radzimska; Dariusz Moszyński; Hermann Ehrlich; Hieronim Maciejewski; Allison L Stelling; Teofil Jesionowski

    2015-01-01

    Innovative materials were made via the combination of chitin and lignin, and the immobilization of lipase from Aspergillus niger. Analysis by techniques including FTIR, XPS and 13C CP MAS NMR confirmed the effective immobilization of the enzyme on the surface of the composite support. The electrokinetic properties of the resulting systems were also determined. Results obtained from elemental analysis and by the Bradford method enabled the determination of optimum parameters for the immobiliza...

  13. Biochemical characterization of chitin synthase activity and inhibition in the African malaria mosquito, Anopheles gambiae

    Institute of Scientific and Technical Information of China (English)

    Xin Zhang; Kun Yan Zhu

    2013-01-01

    Chitin synthase (CHS) is an important enzyme catalyzing the formation of chitin polymers in all chitin containing organisms and a potential target site for insect pest control.However,our understanding of biochemical properties of insect CHSs has been very limited.We here report enzymatic and inhibitory properties of CHS prepared from the African malaria mosquito,Anopheles gambiae.Our study,which represents the first time to use a nonradioactive method to assay CHS activity in an insect species,determined the optimal conditions for measuring the enzyme activity,including pH,temperature,and concentrations of the substrate uridine diphosphate N-acetyl-D-glucosamine (UDPGlcNAc) and Mg++.The optimal pH was about 6.5-7.0,and the highest activity was detected at temperatures between 37℃ and 44℃.Dithithreitol is required to prevent melanization of the enzyme extract.CHS activity was enhanced at low concentration of GlcNAc,but inhibited at high concentrations.Proteolytic activation of the activity is significant both in the 500×g supernatant and the 40 000×g pellet.Our study revealed only slight in vitro inhibition ofA.gambiae CHS activity by diflubenzuron and nikkomycin Z at the highest concentration (2.5μmol/L) examined.There was no in vitro inhibition by polyoxin D at any concentration examined.Furthermore,we did not observe any in vivo inhibition of CHS activity by any of these chemicals at any concentration examined.Our results suggest that the inhibition of chitin synthesis by these chemicals is not due to direct inhibition of CHS in A.gambiae.

  14. Curcumin loaded chitin nanogels for skin cancer treatment via the transdermal route

    Science.gov (United States)

    Mangalathillam, Sabitha; Rejinold, N. Sanoj; Nair, Amrita; Lakshmanan, Vinoth-Kumar; Nair, Shantikumar V.; Jayakumar, Rangasamy

    2011-12-01

    In this study, curcumin loaded chitin nanogels (CCNGs) were developed using biocompatible and biodegradable chitin with an anticancer curcumin drug. Chitin, as well as curcumin, is insoluble in water. However, the developed CCNGs form a very good and stable dispersion in water. The CCNGs were analyzed by DLS, SEM and FTIR and showed spherical particles in a size range of 70-80 nm. The CCNGs showed higher release at acidic pH compared to neutral pH. The cytotoxicity of the nanogels were analyzed on human dermal fibroblast cells (HDF) and A375 (human melanoma) cell lines and the results show that CCNGs have specific toxicity on melanoma in a concentration range of 0.1-1.0 mg mL-1, but less toxicity towards HDF cells. The confocal analysis confirmed the uptake of CCNGs by A375. The apoptotic effect of CCNGs was analyzed by a flow-cytometric assay and the results indicate that CCNGs at the higher concentration of the cytotoxic range showed comparable apoptosis as the control curcumin, in which there was negligible apoptosis induced by the control chitin nanogels. The CCNGs showed a 4-fold increase in steady state transdermal flux of curcumin as compared to that of control curcumin solution. The histopathology studies of the porcine skin samples treated with the prepared materials showed loosening of the horny layer of the epidermis, facilitating penetration with no observed signs of inflammation. These results suggest that the formulated CCNGs offer specific advantage for the treatment of melanoma, the most common and serious type of skin cancer, by effective transdermal penetration.

  15. Effect of Chitin Addition to the Growth of Entomopathogenic fungi Penicillium sp.

    OpenAIRE

    Nurariaty, Agus; Ade, Sugiarti

    2014-01-01

    Penicillium sp. is one of the potentially entomopathogenic fungi to control the cacao pod borer (CPB). The study aims to determine the effect of chitin addition to the growth of entomopathogenic fungi Penicillium sp. Experiments was conducted in Pests Identification and Biological Control laboratory, Department of Plant Pest and Disease, Faculty of Agriculture, Hasanuddin University. The method was conducted that if the fungus Penicillium sp. has grown on PDA, then put in erlemeyer contai...

  16. Methyl jasmonate induces expression of a novel Brassica juncea chitinase with two chitin-binding domains.

    Science.gov (United States)

    Zhao, K J; Chye, M L

    1999-08-01

    We have cloned a 1.3 kb Brassica juncea cDNA encoding BjCHI1, a novel acidic chitinase with two chitin-binding domains that shows 62% identity to Nicotiana tabacum Chia1 chitinase. BjCHI1 is structurally unlike Chia1 that has one chitin-binding domain, but resembles Chia5 chitinase UDA1, the precursor of Urtica dioica agglutinin: however there is only 36.9% identity between them. We propose that BjCHI1 should be classified under a new class, Chia7. The spacer and the hinge region of BjCHI1 are proline-rich, like that of Beta vulgaris Ch1, a Chia6 chitinase with half a chitin-binding domain. Northern blot analysis showed that the 1.3 kb BjCHI1 mRNA is induced by wounding and methyljasmonate (MeJA) treatment but is unaffected by ethylene, salicylic acid (SA) or abscisic acid (ABA). This is the first report on MeJA induction of chitinase gene expression and further suggests that wound-related JA-mediated signal transduction is independent of that involving SA. Western blot analysis using polyclonal antibodies against BjCHI1 showed a cross-reacting band with an apparent molecular mass of 37 kDa in wounded tissues of B. juncea, revealing that, unlike UDA1, BjCHI1 is not cleaved post-translationally at the hinge. Expression of recombinant BjCHI1 in Escherichia coli BL21(DE3) inhibited its growth while crude extracts from E. coli JM109 expressing recombinant BjCHI1 showed chitinase activity. Results from polymerase chain reaction (PCR) suggest that genes encoding chitinases with single or double chitin-binding domains exist in B. juncea. PMID:10527425

  17. Cigarette Smoke-Exposed Candida albicans Increased Chitin Production and Modulated Human Fibroblast Cell Responses

    Directory of Open Access Journals (Sweden)

    Humidah Alanazi

    2014-01-01

    Full Text Available The predisposition of cigarette smokers for development of respiratory and oral bacterial infections is well documented. Cigarette smoke can also contribute to yeast infection. The aim of this study was to investigate the effect of cigarette smoke condensate (CSC on C. albicans transition, chitin content, and response to environmental stress and to examine the interaction between CSC-pretreated C. albicans and normal human gingival fibroblasts. Following exposure to CSC, C. albicans transition from blastospore to hyphal form increased. CSC-pretreated yeast cells became significantly (P<0.01 sensitive to oxidation but significantly (P<0.01 resistant to both osmotic and heat stress. CSC-pretreated C. albicans expressed high levels of chitin, with 2- to 8-fold recorded under hyphal conditions. CSC-pretreated C. albicans adhered better to the gingival fibroblasts, proliferated almost three times more and adapted into hyphae, while the gingival fibroblasts recorded a significantly (P<0.01 slow growth rate but a significantly higher level of IL-1β when in contact with CSC-pretreated C. albicans. CSC was thus able to modulate both C. albicans transition through the cell wall chitin content and the interaction between C. albicans and normal human gingival fibroblasts. These findings may be relevant to fungal infections in the oral cavity in smokers.

  18. Physicochemical properties of physical chitin hydrogels: modeling and relation with the mechanical properties.

    Science.gov (United States)

    Vachoud, L; Domard, A

    2001-01-01

    In this work, we were interested in the modeling of syneresis of physical chitin hydrogels by a mathematic law allowing us to predict the variation of the weight of the gel as a function of time. The variation of the weight of the gel during syneresis can be described by W(t)()/W(0) = (t(1/2) + (W(infinity)/W(0))t)/(t(1/2)) + t) where W(0), W(infinity), and W(t)() are the weights of the gel at the beginning of syneresis, for infinite time and for a time t, respectively. t(1/2) corresponds to the half-time of syneresis. W(infinity)/W(0) and t(1/2) were studied in relation with several parameters such as the ionic strength, pH, degree of acetylation of chitin and the initial concentration of polymer. The mechanical properties of chitin hydrogels maintained during syneresis in media of different pH's and ionic strengths were also investigated.

  19. New photocatalyst based on graphene oxide/chitin for degradation of dyes under sunlight.

    Science.gov (United States)

    Wang, Yuntao; Pei, Yaqiong; Xiong, Wenfei; Liu, Tingguo; Li, Jing; Liu, Shilin; Li, Bin

    2015-11-01

    Sunlight photocatalyst was fabricated by in situ synthesis of Cu2O in the regenerated chitin (RC)/graphene oxide (GO) composite film, where the porous chitin film was used as the microreactor for the formation of nano Cu2O. Nano Cu2O was immobilized and evenly distributed in the matrix and Cu2O tended to grow on the GO sheets. Cu2O inside the matrix excite and generate free photoelectrons and electron holes, which was responsible for the degradation of dyes, while GO transferred the yielded photoelectrons to prevent the generation of local high potential zone and induce the chain degradation at more points. So it was found that the porous chitin film could load Cu2O and graphene at the same time, controlling the size of Cu2O and leading to easy recycle and reuse of the photocatalyst. Moreover, the introduction of GO has dramatically improved the photocatalytic activity of Cu2O in the Cu2O/GO/RC film, showing great potential application in wastewater treatment utilizing solar energy. PMID:26299711

  20. Thermal analysis and structural characterization of chitinous exoskeleton from two marine invertebrates

    Energy Technology Data Exchange (ETDEWEB)

    Juárez-de la Rosa, B.A., E-mail: balej05@yahoo.com.mx [Laboratory of Natural Polymers, CIAD – Coordinación Guaymas, Carretera al Varadero Nacional km. 6.6, Col. Las Playitas, 85480 Guaymas, Sonora (Mexico); Applied Physics Department, CINVESTAV-IPN Unidad Mérida, Carretera antigua a Progreso, km. 6. Apdo, Postal 73, Cordemex, 97310 Mérida, Yucatan (Mexico); May-Crespo, J.; Quintana-Owen, P.; Gónzalez-Gómez, W.S. [Applied Physics Department, CINVESTAV-IPN Unidad Mérida, Carretera antigua a Progreso, km. 6. Apdo, Postal 73, Cordemex, 97310 Mérida, Yucatan (Mexico); Yañez-Limón, J.M. [Materials and Engineering Science, CINVESTAV-IPN, Unidad Querétaro, Libramiento Norponiente No. 2000, Fracc. Real de Juriquilla, 76230 Santiago de Querétaro, Querétaro (Mexico); Alvarado-Gil, J.J., E-mail: jjag@mda.cinvestav.mx [Applied Physics Department, CINVESTAV-IPN Unidad Mérida, Carretera antigua a Progreso, km. 6. Apdo, Postal 73, Cordemex, 97310 Mérida, Yucatan (Mexico)

    2015-06-20

    Highlights: • Thermal analysis of exoskeletons: Antipathes caribbeana and Limulus polyphemus. • DMTA revealed Limulus has a stronger structure with a stepper glass transition. • DSC measurements exhibited a much larger water holding capacity in Antipathes. • X-ray diffraction analysis shows a higher crystallinity index in Limulus • FTIR showed α-chitin structures and high temperature C–N groups prevalence. - ABSTRACT: Thermomechanical and structural properties of two marine species exoskeletons, Antipathes caribbeana (black coral) and Limulus polyphemus (xiphosure), were studied using dynamic mechanical thermal analysis (DMTA), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). DMTA curves indicate the viscoelastic behavior and glass transition around 255 °C, black coral presented a second transition (175 °C) associated to the acetamide group attached to the α-chitin chain. DSC measurements showed a endothermic peak around 100 °C, with enthalpies of 4.02 and 118.04 J/g, indicating strong differences between exoskeletons respect to their water holding capacity and strength water–polymer interaction. A comparative analysis involving DSC and X-ray diffraction showed that lower values ΔH in xiphosure correspond to a material with a higher crystallinity (30), in contrast black coral exhibits higher values ΔH and a lower crystallinity (19). FTIR confirmed α-chitin based structure, at higher temperature diminishes the amide bands and a new one appears, related to C–N groups.

  1. The fungicidal properties of the carbon materials obtained from chitin and chitosan promoted by copper salts

    Energy Technology Data Exchange (ETDEWEB)

    Ilnicka, Anna, E-mail: annakucinska@o2.pl; Walczyk, Mariusz; Lukaszewicz, Jerzy P.

    2015-07-01

    Renewable raw materials chitin and chitosan (N-deacetylated derivative of chitin) were subjected to action of different copper modifiers that were carbonized in the atmosphere of the N{sub 2} inert gas. As a result of the novel manufacturing procedure, a series of carbon materials was obtained with developed surface area and containing copper derivatives of differentiated form, size, and dispersion. The copper modifier and manufacturing procedure (concentration, carbonization temperature) influence the physical–chemical and fungicide properties of the carbons. The received carbons were chemically characterized using several methods like low-temperature adsorption of nitrogen, X-ray diffraction analysis, scanning electron microscopy, cyclic voltammetry, elemental analysis, and bioassay. Besides chemical testing, some biological tests were performed and let to select carbons with the highest fungicidal activity. Such carbons were characteristic of the specific form of copper derivatives occurring in them, i.e., nanocrystallites of Cu{sup 0} and/or Cu{sub 2}O of high dispersion on the surface of carbon. The carbons may find an application as effective contact fungistatic agents in cosmetology, medicine, food industry, etc. - Highlights: • The novel manufacturing procedure yields new functional carbon materials. • Two biopolymers chitin and chitosan can undergo copper(II) ion modification. • The Cu-modified carbon materials exhibit high fungicidal activity. • The fungicidal activity results from the presence of Cu{sup 0} and Cu{sub 2}O nano-crystallites.

  2. Mechanical and thermal properties of crab chitin reinforced carboxylated SBR composites

    Directory of Open Access Journals (Sweden)

    C. Santulli

    2012-05-01

    Full Text Available The addition of small amounts (up to 9 wt% of chitin microsized particles, originating from shellfish waste, to carboxylated styrene-butadiene rubber (XSBR matrix (as received and annealed to 100°C has been studied. In particular, this study concentrated on their mechanical (creep investigation by nanoindentation and dynamical-mechanical analysis, thermal (differential scanning calorimetry and thermogravimetry and swelling behaviour (toluene absorption and was completed by morphological characterisation by scanning electron microscopy and atomic force microscopy. The results show that annealing has a limited effect on materials properties, effects which are further reduced by the addition of growing amounts of crab chitin. It should be noted that the limited filler content used in the study does not substantially modify the linear creep behaviour of XSBR for sufficiently long loading times. The thermal stability of the system does also appear to be preserved even with the maximum chitin content added, while it serves sufficiently as an effective barrier against aromatic solvent absorption.

  3. Molecular Dynamics Simulations of Hydration Effects on Solvation, Diffusivity, and Permeability in Chitosan/Chitin Films.

    Science.gov (United States)

    McDonnell, Marshall T; Greeley, Duncan A; Kit, Kevin M; Keffer, David J

    2016-09-01

    The effects of hydration on the solvation, diffusivity, solubility, and permeability of oxygen molecules in sustainable, biodegradable chitosan/chitin food packaging films were studied via molecular dynamics and confined random walk simulations. With increasing hydration, the membrane has a more homogeneous water distribution with the polymer chains being fully solvated. The diffusivity increased by a factor of 4 for oxygen molecules and by an order of magnitude for water with increasing the humidity. To calculate the Henry's constant and solubility of oxygen in the membranes with changing hydration, the excess chemical potential was calculated via free energy perturbation, thermodynamic integration and direct particle deletion methods. The simulations predicted a higher solubility and permeability for the lower humidity, in contradiction to experimental results. All three methods for calculating the solubility were in good agreement. It was found that the Coulombic interactions in the potential caused the oxygen to bind too strongly to the protonated amine group. Insight from this work will help guide molecular modeling of chitosan/chitin membranes, specifically permeability measurements for small solute molecules. Efforts to chemically tailor chitosan/chitin membranes to favor discrete as opposed to continuous aqueous domains could reduce oxygen permeability. PMID:27487964

  4. An investigation of carbon dioxide capture by chitin acetate/DMSO binary system.

    Science.gov (United States)

    Eftaiha, Ala'a F; Alsoubani, Fatima; Assaf, Khaleel I; Troll, Carsten; Rieger, Bernhard; Khaled, Aseel H; Qaroush, Abdussalam K

    2016-11-01

    Chitin is considered to be the second most abundant naturally-occurring polysaccharide. Also, dimethyl sulfoxide (DMSO) is the second highest dielectric constant polar solvent after water. Despite the low solubility of chitin in common organic solvents, and due to its high nitrogen content, it may serve as a potential scrubbing agent "wet scrubbing" for carbon dioxide (CO2) capturing as an alternative to monoethanolamine "renewables for renewables approach". Briefly, a detailed investigation for the utilization of low molecular weight, chitin-acetate (CA) in DMSO for the capturing of CO2 is reported. As carbonation process takes place, the formation of ionic alkylcarbonate was confirmed throughout spectroscopic and computational studies. Supramolecular chemisorption was proven throughout (1)H Nuclear Magnetic Resonance ((1)H NMR) together with the absence of sorption of CO2 by the monomeric repeating unit, glucosamine hydrochloride. Further, Density Functional Theory (DFT) calculations supported the formation of the CA/CO2 adduct through a newly formed supramolecular ionic interaction and hydrogen bonding along the oligosaccharide backbone between the neighboring ammonium ion and hydroxyl functional groups. The sorption capacity was measured volumetrically within an in situ Attenuated Total Reflectance-Fourier Transform Infrared coupled (in situ ATR-FTIR) autoclave at 25.0°C, and 4.0bar CO2, with a maximum sorption capacity of 3.63 [Formula: see text] /gsorbent at 10.0% (w/v). PMID:27516261

  5. Isocyanate-functionalized chitin and chitosan as gelling agents of castor oil.

    Science.gov (United States)

    Gallego, Rocío; Arteaga, Jesús F; Valencia, Concepción; Franco, José M

    2013-06-03

    The main objective of this work was the incorporation of reactive isocyanate groups into chitin and chitosan in order to effectively use the products as reactive thickening agents in castor oil. The resulting gel-like dispersions could be potentially used as biodegradable lubricating greases. Three different NCO-functionalized polymers were obtained: two of them by promoting the reaction of chitosan with 1,6-hexamethylene diisocyanate (HMDI), and the other by using chitin instead of chitosan. These polymers were characterized through 1H-NMR, FTIR and thermogravimetric analysis (TGA). Thermal and rheological behaviours of the oleogels prepared by dispersing these polymers in castor oil were studied by means of TGA and small-amplitude oscillatory shear (SAOS) measurements. The evolution and values of the linear viscoelasticity functions with frequency for -NCO-functionalized chitosan- and chitin-based oleogels are quite similar to those found for standard lubricating greases. In relation to long-term stability of these oleogels, no phase separation was observed and the values of viscoelastic functions increase significantly during the first seven days of ageing, and then remain almost constant. TGA analysis showed that the degradation temperature of the resulting oleogels is higher than that found for traditional lubricating greases.

  6. Bio-responsive chitin-poly(L-lactic acid) composite nanogels for liver cancer.

    Science.gov (United States)

    Arunraj, T R; Sanoj Rejinold, N; Ashwin Kumar, N; Jayakumar, R

    2014-01-01

    Hepatic carcinoma (HCC) is one of the most common cancer and its treatment has been considered a therapeutic challenge. Doxorubicin (Dox) is one of the most important chemotherapeutic agents used in the treatment for liver cancer. However, the efficacy of Dox therapy is restricted by the dose-dependent toxic side effects. To overcome the cardiotoxicity of Dox as well as the current problems of conventional modality treatment of HCC, we developed a locally injectable, biodegradable, and pH sensitive composite nanogels for site specific delivery. Both control and Dox loaded composite nanogel systems were analyzed by DLS, SEM, FTIR and TG/DTA. The size ranges of the control composite nanogels and their drug loaded counterparts were found to be 90±20 and 270±20 nm, respectively. The control chitin-PLA CNGs and Dox-chitin-PLA CNGs showed higher swelling and degradation in acidic pH. Drug entrapment efficiency and in vitro drug release studies were carried out and showed a higher drug release at acidic pH compared to neutral pH. Cellular internalization of the nanogel systems was confirmed by fluorescent microscopy. The cytotoxicity of the composite nanogels was analyzed toward HepG2 (human liver cancer) cell lines. Furthermore, the results of in vitro hemolytic assay and coagulation assay substantiate the blood compatibility of the system. Overall Dox-chitin-PLA CNGs system could be a promising anticancer drug delivery system for liver cancer therapy. PMID:24129331

  7. An investigation of carbon dioxide capture by chitin acetate/DMSO binary system.

    Science.gov (United States)

    Eftaiha, Ala'a F; Alsoubani, Fatima; Assaf, Khaleel I; Troll, Carsten; Rieger, Bernhard; Khaled, Aseel H; Qaroush, Abdussalam K

    2016-11-01

    Chitin is considered to be the second most abundant naturally-occurring polysaccharide. Also, dimethyl sulfoxide (DMSO) is the second highest dielectric constant polar solvent after water. Despite the low solubility of chitin in common organic solvents, and due to its high nitrogen content, it may serve as a potential scrubbing agent "wet scrubbing" for carbon dioxide (CO2) capturing as an alternative to monoethanolamine "renewables for renewables approach". Briefly, a detailed investigation for the utilization of low molecular weight, chitin-acetate (CA) in DMSO for the capturing of CO2 is reported. As carbonation process takes place, the formation of ionic alkylcarbonate was confirmed throughout spectroscopic and computational studies. Supramolecular chemisorption was proven throughout (1)H Nuclear Magnetic Resonance ((1)H NMR) together with the absence of sorption of CO2 by the monomeric repeating unit, glucosamine hydrochloride. Further, Density Functional Theory (DFT) calculations supported the formation of the CA/CO2 adduct through a newly formed supramolecular ionic interaction and hydrogen bonding along the oligosaccharide backbone between the neighboring ammonium ion and hydroxyl functional groups. The sorption capacity was measured volumetrically within an in situ Attenuated Total Reflectance-Fourier Transform Infrared coupled (in situ ATR-FTIR) autoclave at 25.0°C, and 4.0bar CO2, with a maximum sorption capacity of 3.63 [Formula: see text] /gsorbent at 10.0% (w/v).

  8. Role of Chitin and Chitinase/Chitinase-Like Proteins in Inflammation, Tissue Remodeling, and Injury

    Science.gov (United States)

    Lee, Chun Geun; Da Silva, Carla A.; Dela Cruz, Charles S.; Ahangari, Farida; Ma, Bing; Kang, Min-Jong; He, Chuan-Hua; Takyar, Seyedtaghi; Elias, Jack A.

    2013-01-01

    The 18 glycosyl hydrolase family of chitinases is an ancient gene family that is widely expressed from prokaryotes to eukaryotes. In mammals, despite the absence of endogenous chitin, a number of chitinases and chitinase-like proteins (C/CLPs) have been identified. However, their roles have only recently begun to be elucidated. Acidic mammalian chitinase (AMCase) inhibits chitin-induced innate inflammation; augments chitin-free, allergen-induced Th2 inflammation; and mediates effector functions of IL-13. The CLPs BRP-39/YKL-40 (also termed chitinase 3-like 1) inhibit oxidant-induced lung injury, augments adaptive Th2 immunity, regulates apoptosis, stimulates alternative macrophage activation, and contributes to fibrosis and wound healing. In accord with these findings, levels of YKL-40 in the lung and serum are increased in asthma and other inflammatory and remodeling disorders and often correlate with disease severity. Our understanding of the roles of C/CLPs in inflammation, tissue remodeling, and tissue injury in health and disease is reviewed below. PMID:21054166

  9. Co-Processed Chitin-Mannitol as a New Excipient for Oro-Dispersible Tablets

    Directory of Open Access Journals (Sweden)

    Nidal Daraghmeh

    2015-03-01

    Full Text Available This study describes the preparation, characterization and performance of a novel excipient for use in oro-dispersible tablets (ODT. The excipient (Cop–CM consists of chitin and mannitol. The excipient with optimal physicochemical properties was obtained at a chitin: mannitol ratio of 2:8 (w/w and produced by roll compaction (RC. Differential scanning calorimetry (DSC, Fourier transform-Infrared (FT-IR, X-ray powder diffraction (XRPD and scanning electron microscope (SEM techniques were used to characterize Cop–CM, in addition to characterization of its powder and ODT dosage form. The effect of particle size distribution of Cop–CM was investigated and found to have no significant influence on the overall tablet physical properties. The compressibility parameter (a for Cop–CM was calculated from a Kawakita plot and found to be higher (0.661 than that of mannitol (0.576 due to the presence of the highly compressible chitin (0.818. Montelukast sodium and domperidone ODTs produced, using Cop–CM, displayed excellent physicochemical properties. The exceptional binding, fast wetting and superdisintegration properties of Cop–CM, in comparison with commercially available co-processed ODT excipients, results in a unique multifunctional base which can successfully be used in the formulation of oro-dispersible and fast immediate release tablets.

  10. Chitin and Chitosan Preparation from Marine Sources. Structure, Properties and Applications

    Directory of Open Access Journals (Sweden)

    Islem Younes

    2015-03-01

    Full Text Available This review describes the most common methods for recovery of chitin from marine organisms. In depth, both enzymatic and chemical treatments for the step of deproteinization are compared, as well as different conditions for demineralization. The conditions of chitosan preparation are also discussed, since they significantly impact the synthesis of chitosan with varying degree of acetylation (DA and molecular weight (MW. In addition, the main characterization techniques applied for chitin and chitosan are recalled, pointing out the role of their solubility in relation with the chemical structure (mainly the acetyl group distribution along the backbone. Biological activities are also presented, such as: antibacterial, antifungal, antitumor and antioxidant. Interestingly, the relationship between chemical structure and biological activity is demonstrated for chitosan molecules with different DA and MW and homogeneous distribution of acetyl groups for the first time. In the end, several selected pharmaceutical and biomedical applications are presented, in which chitin and chitosan are recognized as new biomaterials taking advantage of their biocompatibility and biodegradability.

  11. Binary gene expression patterning of the molt cycle: the case of chitin metabolism.

    Directory of Open Access Journals (Sweden)

    Shai Abehsera

    Full Text Available In crustaceans, like all arthropods, growth is accompanied by a molting cycle. This cycle comprises major physiological events in which mineralized chitinous structures are built and degraded. These events are in turn governed by genes whose patterns of expression are presumably linked to the molting cycle. To study these genes we performed next generation sequencing and constructed a molt-related transcriptomic library from two exoskeletal-forming tissues of the crayfish Cherax quadricarinatus, namely the gastrolith and the mandible cuticle-forming epithelium. To simplify the study of such a complex process as molting, a novel approach, binary patterning of gene expression, was employed. This approach revealed that key genes involved in the synthesis and breakdown of chitin exhibit a molt-related pattern in the gastrolith-forming epithelium. On the other hand, the same genes in the mandible cuticle-forming epithelium showed a molt-independent pattern of expression. Genes related to the metabolism of glucosamine-6-phosphate, a chitin precursor synthesized from simple sugars, showed a molt-related pattern of expression in both tissues. The binary patterning approach unfolds typical patterns of gene expression during the molt cycle of a crustacean. The use of such a simplifying integrative tool for assessing gene patterning seems appropriate for the study of complex biological processes.

  12. Cigarette smoke-exposed Candida albicans increased chitin production and modulated human fibroblast cell responses.

    Science.gov (United States)

    Alanazi, Humidah; Semlali, Abdelhabib; Perraud, Laura; Chmielewski, Witold; Zakrzewski, Andrew; Rouabhia, Mahmoud

    2014-01-01

    The predisposition of cigarette smokers for development of respiratory and oral bacterial infections is well documented. Cigarette smoke can also contribute to yeast infection. The aim of this study was to investigate the effect of cigarette smoke condensate (CSC) on C. albicans transition, chitin content, and response to environmental stress and to examine the interaction between CSC-pretreated C. albicans and normal human gingival fibroblasts. Following exposure to CSC, C. albicans transition from blastospore to hyphal form increased. CSC-pretreated yeast cells became significantly (P < 0.01) sensitive to oxidation but significantly (P < 0.01) resistant to both osmotic and heat stress. CSC-pretreated C. albicans expressed high levels of chitin, with 2- to 8-fold recorded under hyphal conditions. CSC-pretreated C. albicans adhered better to the gingival fibroblasts, proliferated almost three times more and adapted into hyphae, while the gingival fibroblasts recorded a significantly (P < 0.01) slow growth rate but a significantly higher level of IL-1β when in contact with CSC-pretreated C. albicans. CSC was thus able to modulate both C. albicans transition through the cell wall chitin content and the interaction between C. albicans and normal human gingival fibroblasts. These findings may be relevant to fungal infections in the oral cavity in smokers. PMID:25302312

  13. Application of chitin and chitosan as elicitors of coumarins and fluoroquinolone alkaloids in Ruta graveolens L. (common rue).

    Science.gov (United States)

    Orlita, Aleksandra; Sidwa-Gorycka, Matylda; Paszkiewicz, Monika; Malinski, Edmund; Kumirska, Jolanta; Siedlecka, Ewa M; Łojkowska, Ewa; Stepnowski, Piotr

    2008-10-01

    Common rue (Ruta graveolens L.) accumulates various types of secondary metabolites, such as coumarins furanocoumarins, acridone and quinolone alkaloids and flavonoids. Elicitation is a tool extensively used for enhancing secondary-metabolite yields. Chitin and chitosan are examples of elicitors inducing phytoalexin accumulation in plant tissue. The present paper describes the application of chitin and chitosan as potential elicitors of secondary-metabolite accumulation in R. graveolens shoots cultivated in vitro. The simple coumarins, linear furanocoumarins, dihydrofuranocoumarins and fluoroquinolone alkaloids biosynthesized in the presence of chitin and chitosan were isolated, separated and identified. There was a significant increase in the growth rate of R. graveolens shoots in the presence of either chitin or chitosan. Moreover, the results of the elicitation of coumarins and alkaloids accumulated by R. graveolens shoots in the presence of chitin and chitosan show that both compounds induced a significant increase in the concentrations of nearly all the metabolites. Adding 0.01% chitin caused the increase in the quantity (microg/g dry weight) of coumarins (pinnarin up to 116.7, rutacultin up to 287.0, bergapten up to 904.3, isopimpinelin up to 490.0, psoralen up to 522.2, xanhotoxin up to 1531.5 and rutamarin up to 133.7). The higher concentration of chitosan (0.1%) induced production of simple coumarins (pinnarin up to 116.7 and rutacultin up to 287.0), furanocoumarins (bergapten up to 904.3, isopimpinelin up to 490.0, psoralen up to 522.2, xanhotoxin up to 1531.5) and dihydrofuranocoumarins (chalepin up to 18 and rutamarin up to 133.7). Such a dramatic increase in the production of nearly all metabolites suggests that these compounds may be participating in the natural resistance mechanisms of R. graveolens. The application of chitin- and chitosan-containing media may be considered a promising prospect in the biotechnological production of xanthotoxin

  14. Molecular cloning and expression of chitin deacetylase 1 gene from the gills of Penaeus monodon (black tiger shrimp).

    Science.gov (United States)

    Sarmiento, Katreena P; Panes, Vivian A; Santos, Mudjekeewis D

    2016-08-01

    Chitin deacetylases have been identified and studied in several fungi and insects but not in crustaceans. These glycoproteins function in catalyzing the conversion of chitin to chitosan by the hydrolysis of N-acetamido bonds of chitin. Here, for the first time, the full length cDNA of chitin deacetylase (CDA) gene from crustaceans was fully cloned using a partial fragment obtained from a transcriptome database of the gills of black tiger shrimp Penaeus monodon that survived White Spot Syndrome Virus (WSSV) infection employing Rapid Amplification of cDNA Ends (RACE) PCR. The shrimp CDA, named PmCDA1, was further characterized by in silico analysis, and its constitutive expression determined in apparently healthy shrimp through reverse transcription PCR (RT-PCR). Results revealed that the P. monodon chitin deacetylase (PmCDA1) is 2176 bp-long gene with an open reading frame (ORF) of 1596 bp encoding for 532 amino acids. Phylogenetic analysis revealed that PmCDA1 belongs to Group I CDAs together with CDA1 and CDA2 proteins found in insects. Moreover, PmCDA1 is composed of a conserved chitin-binding peritrophin-A domain (CBD), a low-density lipoprotein receptor class A domain (LDL-A) and a catalytic domain that is part of CE4 superfamily, all found in group I CDAs, which are known to serve critical immune function against WSSV. Finally, high expression of PmCDA1 gene in the gills of apparently healthy P. monodon was observed suggesting important basal function of the gene in this tissue. Taken together, this is a first report of the full chitin deacetylase 1 (CDA1) gene in crustaceans particularly in shrimp that exhibits putative immune function against WSSV and is distinctly highly expressed in the gills of shrimp. PMID:27335260

  15. Candida antarctica Lipase B Immobilized onto Chitin Conjugated with POSS® Compounds: Useful Tool for Rapeseed Oil Conversion

    Directory of Open Access Journals (Sweden)

    Jakub Zdarta

    2016-09-01

    Full Text Available A new method is proposed for the production of a novel chitin-polyhedral oligomeric silsesquioxanes (POSS enzyme support. Analysis by such techniques as X-ray photoelectron spectroscopy (XPS and Raman spectroscopy confirmed the effective functionalization of the chitin surface. The resulting hybrid carriers were used in the process of immobilization of the lipase type b from Candida antarctica (CALB. Fourier transform infrared spectroscopy (FTIR confirmed the effective immobilization of the enzyme. The tests of the catalytic activity showed that the resulting support-biocatalyst systems remain hydrolytically active (retention of the hydrolytic activity up to 87% for the chitin + Methacryl POSS® cage mixture (MPOSS + CALB after 24 h of the immobilization, as well as represents good thermal and operational stability, and retain over 80% of its activity in a wide range of temperatures (30–60 °C and pH (6–9. Chitin-POSS-lipase systems were used in the transesterification processes of rapeseed oil at various reaction conditions. Produced systems allowed the total conversion of the oil to fatty acid methyl esters (FAME and glycerol after 24 h of the process at pH 10 and a temperature 40 °C, while the Methacryl POSS® cage mixture (MPOSS was used as a chitin-modifying agent.

  16. Phase distribution of products of radiation and post-radiation distillation of biopolymers: Cellulose, lignin and chitin

    International Nuclear Information System (INIS)

    Influence of both the absorbed dose and the dose rate of 8 MeV electron-beam radiation on destruction of microcrystalline cellulose, pine lignin and krill chitin was investigated. Two conversion modes were compared: (1) post-radiation distillation PRD and (2) electron-beam distillation EBD. Cellulose, chitin and lignin demonstrate different responses to irradiation and distillation in PRD and EBD modes. Treatment in EBD mode transforms biopolymers to organic liquid more productively than conventional dry distillation and treatment in PRD mode. Both radiation heating and an irradiation without heating intensify chitin and cellulose decomposition and distillation. At the same time lignin decaying rather efficiently in EBD mode appears to be insensitive to a preliminary irradiation in PRD mode up to a dose of 2.4 MGy. - Highlights: → Direct conversion of cellulose, chitin and lignin to organic liquid is intensified by electron-beam irradiation. → Alternative approach to bio-oil production. → Both electron-beam distillation mode and post-radiation distillation mode are effective for cellulose and chitin conversion. → Electron-beam distillation mode is preferable for lignin conversion. → Preliminary deep dehydration of biopolymers is realizable at low dose rates.

  17. Phase distribution of products of radiation and post-radiation distillation of biopolymers: Cellulose, lignin and chitin

    Energy Technology Data Exchange (ETDEWEB)

    Ponomarev, A.V., E-mail: ponomarev@ipc.rssi.ru [A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninsky Prospect 31, 119991 Moscow (Russian Federation); Kholodkova, E.M.; Metreveli, A.K.; Metreveli, P.K.; Erasov, V.S.; Bludenko, A.V.; Chulkov, V.N. [A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninsky Prospect 31, 119991 Moscow (Russian Federation)

    2011-11-15

    Influence of both the absorbed dose and the dose rate of 8 MeV electron-beam radiation on destruction of microcrystalline cellulose, pine lignin and krill chitin was investigated. Two conversion modes were compared: (1) post-radiation distillation PRD and (2) electron-beam distillation EBD. Cellulose, chitin and lignin demonstrate different responses to irradiation and distillation in PRD and EBD modes. Treatment in EBD mode transforms biopolymers to organic liquid more productively than conventional dry distillation and treatment in PRD mode. Both radiation heating and an irradiation without heating intensify chitin and cellulose decomposition and distillation. At the same time lignin decaying rather efficiently in EBD mode appears to be insensitive to a preliminary irradiation in PRD mode up to a dose of 2.4 MGy. - Highlights: > Direct conversion of cellulose, chitin and lignin to organic liquid is intensified by electron-beam irradiation. > Alternative approach to bio-oil production. > Both electron-beam distillation mode and post-radiation distillation mode are effective for cellulose and chitin conversion. > Electron-beam distillation mode is preferable for lignin conversion. > Preliminary deep dehydration of biopolymers is realizable at low dose rates.

  18. Candida antarctica Lipase B Immobilized onto Chitin Conjugated with POSS® Compounds: Useful Tool for Rapeseed Oil Conversion

    Science.gov (United States)

    Zdarta, Jakub; Wysokowski, Marcin; Norman, Małgorzata; Kołodziejczak-Radzimska, Agnieszka; Moszyński, Dariusz; Maciejewski, Hieronim; Ehrlich, Hermann; Jesionowski, Teofil

    2016-01-01

    A new method is proposed for the production of a novel chitin-polyhedral oligomeric silsesquioxanes (POSS) enzyme support. Analysis by such techniques as X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy confirmed the effective functionalization of the chitin surface. The resulting hybrid carriers were used in the process of immobilization of the lipase type b from Candida antarctica (CALB). Fourier transform infrared spectroscopy (FTIR) confirmed the effective immobilization of the enzyme. The tests of the catalytic activity showed that the resulting support-biocatalyst systems remain hydrolytically active (retention of the hydrolytic activity up to 87% for the chitin + Methacryl POSS® cage mixture (MPOSS) + CALB after 24 h of the immobilization), as well as represents good thermal and operational stability, and retain over 80% of its activity in a wide range of temperatures (30–60 °C) and pH (6–9). Chitin-POSS-lipase systems were used in the transesterification processes of rapeseed oil at various reaction conditions. Produced systems allowed the total conversion of the oil to fatty acid methyl esters (FAME) and glycerol after 24 h of the process at pH 10 and a temperature 40 °C, while the Methacryl POSS® cage mixture (MPOSS) was used as a chitin-modifying agent. PMID:27657054

  19. Synergistic action of serine- and metallo-proteases from Fusarium oxysporum f. sp. lycopersici cleaves chitin-binding tomato chitinases, reduces their antifungal activity and enhances fungal virulence

    NARCIS (Netherlands)

    Karimi Jashni, M.; Dols, I.; Iida, Y.; Boeren, S.; Beenen, H.G.; Mehrabi, R.; Collemare, J.; Wit, de P.J.G.M.

    2015-01-01

    As part of their defence strategy against fungal pathogens, plants secrete chitinases that degrade chitin, the major structural component of fungal cell walls. Some fungi are not sensitive to plant chitinases because they secrete chitin-binding effector proteins that protect their cell wall against

  20. Resilin and chitinous cuticle form a composite structure for energy storage in jumping by froghopper insects

    Directory of Open Access Journals (Sweden)

    Shaw Stephen R

    2008-09-01

    Full Text Available Abstract Background Many insects jump by storing and releasing energy in elastic structures within their bodies. This allows them to release large amounts of energy in a very short time to jump at very high speeds. The fastest of the insect jumpers, the froghopper, uses a catapult-like elastic mechanism to achieve their jumping prowess in which energy, generated by the slow contraction of muscles, is released suddenly to power rapid and synchronous movements of the hind legs. How is this energy stored? Results The hind coxae of the froghopper are linked to the hinges of the ipsilateral hind wings by pleural arches, complex bow-shaped internal skeletal structures. They are built of chitinous cuticle and the rubber-like protein, resilin, which fluoresces bright blue when illuminated with ultra-violet light. The ventral and posterior end of this fluorescent region forms the thoracic part of the pivot with a hind coxa. No other structures in the thorax or hind legs show this blue fluorescence and it is not found in larvae which do not jump. Stimulating one trochanteral depressor muscle in a pattern that simulates its normal action, results in a distortion and forward movement of the posterior part of a pleural arch by 40 μm, but in natural jumping, the movement is at least 100 μm. Conclusion Calculations showed that the resilin itself could only store 1% to 2% of the energy required for jumping. The stiffer cuticular parts of the pleural arches could, however, easily meet all the energy storage needs. The composite structure therefore, combines the stiffness of the chitinous cuticle with the elasticity of resilin. Muscle contractions bend the chitinous cuticle with little deformation and therefore, store the energy needed for jumping, while the resilin rapidly returns its stored energy and thus restores the body to its original shape after a jump and allows repeated jumping.

  1. Management of Plant-parasitic Nematodes with a Chitin-Urea Soil Amendment and Other Materials.

    Science.gov (United States)

    Westerdahl, B B; Carlson, H L; Grant, J; Radewald, J D; Welch, N; Anderson, C A; Darso, J; Kirby, D; Shibuya, F

    1992-12-01

    Field trials were conducted with a chitin-urea soil amendment and several other nematicides on four crop-nematode combinations: tomato-Meloidogyne incognita; potato-Meloidogyne chitwoodi; walnut-Pratylenchus vulnus; and brussels sprouts-Heterodera schachtii. Significant (P soil amendment in the trims on potato and walnut. In the trials on brussels sprouts and on tomato, phytotoxicity occurred at rates of 1,868 and 1,093 kg/ha, respectively. Significant (P Yucca extract on tomato; and dazomet granules on brussels sprouts. PMID:19283044

  2. Biochemical and morphological responses to abiotc elicitor chitin in suspension-cultured sugarcane cells

    Directory of Open Access Journals (Sweden)

    Maria Izabel Gallão

    2010-04-01

    Full Text Available Cells of Saccharum officinarum submitted to hydrolyzated chitin for 1 to 8h produced phenolic compounds. These alterations were observed through cytochemical methods using Toluidine Blue and Phloroglucinol/HCl. After 4 h, besides cell wall change, there was a change in nuclear pattern of chitin treated cells. There was a 96% increase in nuclear area in 6 h chitin treated material, as observed by Feulgen reaction. The treated cells showed chromatin compacted regions and a degeneration process of nucleoli. In the outer areas of cell wall, there was a polysaccharide desagregation, confirming results obtained for different plants with the use of other elicitors. Peroxidase activity was maximal after 4 h and decreased progressively. PAL activity started to increase at 4 h of incubation. These results showed that chitin hydrolyzate stimulated a defense response in sugarcane cells.Células de Saccharum officinarum quando submetidas a quitina hidrolisada por 1 a 8h produziram material fenólico. Essas alterações foram observadas por meio de métodos citoquímicos como o Azul de Toluidina e Floroglucinol/HCl. Após 4 h, além das mudanças nas paredes celulares houve uma mudança no padrão nuclear das células tratadas com quitina. Por observação da reação de Feulgen, houve um aumento de 96% na área nuclear no material em 6h. Para as células tratadas foram observadas regiões de cromatina compactada e um processo de degeneração do nucléolo. Nas áreas externas da parede celular existia uma desagregação dos polisacarídios confirmando os resultados obtidos para diferentes plantas com o uso de outros elicitores. A atividade da peroxidase foi maxima após 4 h e então decresceu progressivamente. A atividade da PAL aumentou a partir de 4 h de incubação. Estes resultados mostram que o hidrolisado de quitina estimula as respostas de defesa em células de cana.

  3. Obtention and characterization of chitin and chitosan from M. rosenbergii; Obtencao e caracterizacao de quitina e quitosana a partr de M. rosenbergii

    Energy Technology Data Exchange (ETDEWEB)

    Battisti, Marcos V.; Campana Filho, Sergio P. [Sao Paulo Univ., Sao Carlos, SP (Brazil). Inst. de Quimica]. E-mail: scampana@iqsc.sc.usp.br

    2001-07-01

    Chitin was extracted from previously ground shells of Macrobrachium rosenbergii by applying acid and alkaline treatments, aiming at its demineralization and deprotenization, respectively. Its characteristics and properties were compared with those exhibited by commercial samples of chitin. Commercial chitosan and samples produced by the deacetylation of chitin obtained from M. rosenbergii shells were also compared. Average degrees of acetylation and intrinsic viscosities of the chitosan were determined by {sup 1}H NMR spectroscopy and by capillary viscosimetry, respectively. The results show that the chitin extracted from Macrobrachium rosenbergii has a lower content of inorganic materials as compared to commercial samples but the chitosan obtained from the former chitin sample is very similar to commercial chitosan. (author)

  4. ADVANCE IN SOLVENTS OF CHITIN AND ITS APPLICATION%甲壳素良溶剂及其应用

    Institute of Scientific and Technical Information of China (English)

    刘廷国; 查萍萍; 李斌

    2011-01-01

    甲壳素是一种非常重要的高附加值生物质资源,由于无法溶于水、稀酸、稀碱和一般的有机溶剂,极大地限制了其广泛应用.目前寻找合适的甲壳素良溶剂仍是一个非常具有挑战性的课题.国内外文献中尚无专门的甲壳素溶剂方面的综述文章.本文综述了甲壳素的常用良溶剂,包括无机盐、浓酸、浓碱、氟化试剂和酰胺/氯化锂等溶剂.期望为甲壳素的深入研究和利用提供基础的文献参考.%Chitin is the second most abundant natural biopolymer on earth after cellulose, which is regarded as a high value-added biomass resource. However, it is insoluble in water, diluted acid, alkaline solution, and common organic solvents, due to the existence of strong intra- and inter- molecular hydrogen bonds. This strongly restricts many applications of chitin in many fields. Therefore, it is still a challenging study for searching better chitin solvents. In the literature, there are no special review articles for chitin solvent. This paper reviews the common good solvent of chitin, such as inorganic salts, concentrated acids or alkaline solutions, fluorinated solvents and amide/LiCl systems, and so on. Which is expected to provide a basic literature reference for further research and utilization of chitin.

  5. Effect of plagiochin E, an antifungal macrocyclic bis(bibenzyl), on cell wall chitin synthesis in Candida albicans

    Institute of Scientific and Technical Information of China (English)

    Xiu-zhen WU; Ai-xia CHENG; Ling-mei SUN; Hong-xiang LOU

    2008-01-01

    Aim: To investigate the effect of plagiochin E (PLE), an antifungal macrocyclic bis(bibenzyl) isolated from liverwort Marchantia polymorpha L, on cell wall chitin synthesis in Candida albicans. Methods: The effect of PLE on chitin synthesis in Candida albicans was investigated at the cellular and molecular lev-els. First, the ultrastructural changes were observed under transmission electron microscopy (TEM). Second, the effects of PLE on chitin synthetase (Chs) activi-ties in vitro were assayed using 6-O-dansyl-N-acetylglucosamine as a fluorescent substrate, and its effect on chitin synthesis in situ was assayed by spheroplast regeneration. Finally, real-time RT-PCR was performed to assay its effect on the expression of Chs genes (CHS). Results: Observation under TEM showed that the structure of the cell wall in Candida albicans was seriously damaged, which suggested that the antifungal activity of PLE was associated with its effect on the cell wail. Enzymatic assays and spheroplast regeneration showed that PLE inhibited chitin synthesis in vitro and in situ. The results of the PCR showed that PLE significantly downregulated the expression of CHS1, and upregulated the expression of CHS2 and CHS3. Because different Chs is regulated at different stages of transcription and post-translation, the downregulation of CHS1 would decrease the level of Chs 1 and inhibit its activity, and the inhibitory effects of PLE on Chs2 and Chs3 would be at the post-translational level or by the inhibi-tion on the enzyme-active center. Conclusion: These results indicate that the antifungal activity of PLE would be attributed to its inhibitory effect on cell wall chitin synthesis in Candida albicans.

  6. Different functions of the insect soluble and membrane-bound trehalase genes in chitin biosynthesis revealed by RNA interference.

    Directory of Open Access Journals (Sweden)

    Jie Chen

    Full Text Available BACKGROUND: Trehalase, an enzyme that hydrolyzes trehalose to yield two glucose molecules, plays a pivotal role in various physiological processes. In recent years, trehalase proteins have been purified from several insect species and are divided into soluble (Tre-1 and membrane-bound (Tre-2 trehalases. However, no functions of the two trehalases in chitin biosynthesis in insects have yet been reported. PRINCIPAL FINDINGS: The membrane-bound trehalase of Spodoptera exigua (SeTre-2 was characterized in our laboratory previously. In this study, we cloned the soluble trehalase gene (SeTre-1 and investigated the tissue distribution and developmental expression pattern of the two trehalase genes. SeTre-1 was expressed highly in cuticle and Malpighian tubules, while SeTre-2 was expressed in tracheae and fat body. In the midgut, the two trehalase genes were expressed in different locations. Additionally, the expression profiles of both trehalase mRNAs and their enzyme activities suggest that they may play different roles in chitin biosynthesis. The RNA interference (RNAi of either SeTre-1 or SeTre-2 was gene-specific and effective, with efficiency rates up to 83% at 72 h post injection. After RNAi of SeTre-1 and SeTre-2, significant higher mortality rates were observed during the larva-pupa stage and pupa-adult stage, and the lethal phenotypes were classified and analyzed. Additionally, the change trends of concentration of trehalose and glucose appeared reciprocally in RNAi-mutants. Moreover, knockdown of SeTre-1 gene largely inhibited the expression of chitin synthase gene A (CHSA and reduced the chitin content in the cuticle to two-thirds relative to the control insects. The chitin synthase gene B (CHSB expression, however, was inhibited more by the injection of dsRNA for SeTre-2, and the chitin content in the midgut decreased by about 25%. CONCLUSIONS: SeTre-1 plays a major role in CHSA expression and chitin synthesis in the cuticle, and SeTre-2

  7. Chitin synthases from Saprolegnia are involved in tip growth and represent a potential target for anti-oomycete drugs.

    Directory of Open Access Journals (Sweden)

    Gea Guerriero

    Full Text Available Oomycetes represent some of the most devastating plant and animal pathogens. Typical examples are Phytophthora infestans, which causes potato and tomato late blight, and Saprolegnia parasitica, responsible for fish diseases. Despite the economical and environmental importance of oomycete diseases, their control is difficult, particularly in the aquaculture industry. Carbohydrate synthases are vital for hyphal growth and represent interesting targets for tackling the pathogens. The existence of 2 different chitin synthase genes (SmChs1 and SmChs2 in Saprolegnia monoica was demonstrated using bioinformatics and molecular biology approaches. The function of SmCHS2 was unequivocally demonstrated by showing its catalytic activity in vitro after expression in Pichia pastoris. The recombinant SmCHS1 protein did not exhibit any activity in vitro, suggesting that it requires other partners or effectors to be active, or that it is involved in a different process than chitin biosynthesis. Both proteins contained N-terminal Microtubule Interacting and Trafficking domains, which have never been reported in any other known carbohydrate synthases. These domains are involved in protein recycling by endocytosis. Enzyme kinetics revealed that Saprolegnia chitin synthases are competitively inhibited by nikkomycin Z and quantitative PCR showed that their expression is higher in presence of the inhibitor. The use of nikkomycin Z combined with microscopy showed that chitin synthases are active essentially at the hyphal tips, which burst in the presence of the inhibitor, leading to cell death. S. parasitica was more sensitive to nikkomycin Z than S. monoica. In conclusion, chitin synthases with species-specific characteristics are involved in tip growth in Saprolegnia species and chitin is vital for the micro-organisms despite its very low abundance in the cell walls. Chitin is most likely synthesized transiently at the apex of the cells before cellulose, the major

  8. Preparation of chitin–silica composites by in vitro silicification of two-dimensional Ianthella basta demosponge chitinous scaffolds under modified Stöber conditions

    Energy Technology Data Exchange (ETDEWEB)

    Wysokowski, Marcin [Institute of Chemical Technology and Engineering, Faculty of Chemical Technology, Poznan University of Technology, M. Skłodowskiej-Curie 2, PL-60965 Poznan (Poland); Behm, Thomas [Institute of Experimental Physics, TU Bergakademie Freiberg, Liepziger 23, 09599 Freiberg (Germany); Born, René [Institute of Materials Science, Dresden University of Technology, Helmholtzstraße 10, 01069 Dresden (Germany); Bazhenov, Vasilii V. [Institute of Experimental Physics, TU Bergakademie Freiberg, Liepziger 23, 09599 Freiberg (Germany); Meißner, Heike; Richter, Gert [Faculty of Medicine Carl Gustav Carus, Dresden University of Technology, Fetscherstraße 74, 01307 Dresden (Germany); Szwarc-Rzepka, Karolina [Institute of Chemical Technology and Engineering, Faculty of Chemical Technology, Poznan University of Technology, M. Skłodowskiej-Curie 2, PL-60965 Poznan (Poland); Makarova, Anna; Vyalikh, Denis [Institute of Solid State Physics, Dresden University of Technology, Helmholtzstraße 10, 01069 Dresden (Germany); Schupp, Peter [Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg, Emsstr. 20, 26382 Wilhelmshaven (Germany); Jesionowski, Teofil, E-mail: teofil.jesionowski@put.poznan.pl [Institute of Chemical Technology and Engineering, Faculty of Chemical Technology, Poznan University of Technology, M. Skłodowskiej-Curie 2, PL-60965 Poznan (Poland); Ehrlich, Hermann, E-mail: hermann.ehrlich@physik.tu-freiberg.de [Institute of Experimental Physics, TU Bergakademie Freiberg, Liepziger 23, 09599 Freiberg (Germany)

    2013-10-15

    Chitin is a biopolymer found in cell walls of various fungi and skeletal structures of numerous invertebrates. The occurrence of chitin within calcium- and silica-containing biominerals has inspired development of chitin-based hybrids and composites in vitro with specific physico-chemical and material properties. We show here for the first time that the two-dimensional α-chitin scaffolds isolated from the skeletons of marine demosponge Ianthella basta can be effectively silicified by the two-step method with the use of Stöber silica micro- and nanodispersions under Extreme Biomimetic conditions. The chitin–silica composites obtained at 120 °C were characterized by the presence of spherical SiO{sub 2} particles homogeneously distributed over the chitin fibers, which probably follows from the compatibility of Si–OH groups to the hydroxyl groups of chitin. The biocomposites obtained were characterized by various analytical techniques such as energy dispersive spectrometry, scanning electron microscopy, thermogravimetric/differential thermal analyses as well as X-ray photoelectron spectroscopy, Fourier transform infrared and Raman spectroscopy to determine possible interactions between silica and chitin molecule. The results presented proved that the character and course of the in vitro chitin silicification in Stöber dispersions depended considerably on the degree of hydrolysis of the SiO{sub 2} precursor. - Highlights: • 2D α-chitin scaffolds isolated from marine demosponge can be effectively silicified using Stöber silica. • The chitin–silica composites were obtained under Extreme Biomimetic conditions. • Character and course of the in vitro chitin silicification in Stöber dispersions is discussed.

  9. Identification and Molecular Characterization of a Chitin Deacetylase from Bombyx mori Peritrophic Membrane

    Directory of Open Access Journals (Sweden)

    Xiao-Wu Zhong

    2014-01-01

    Full Text Available The insect midgut epithelium is generally lined with a unique chitin and protein structure, the peritrophic membrane (PM, which facilitates food digestion and protects the gut epithelium. PM proteins are important determinants for PM structure and formation. In this study, the silkworm Bombyx mori midgut PM protein BmCDA7 was identified by proteomic tools. The full-length BmCDA7 cDNA is 1357 bp; the deduced protein is composed of 379 amino acid residues and includes a 16 amino acid residue signal peptide, a putative polysaccharide deacetylase-like domain and 15 cysteine residues present in three clusters. The heterologously expressed proteins of the BmCDA7 gene in yeast displayed chitin deacetylase activity. Expression of B. mori BmCDA7 was detected in the midgut at both the transcriptional and translational levels. The BmCDA7 gene was expressed by the newly hatched silkworm larvae until day seven of the fifth instar and was expressed at a high level in the newly exuviated larvae of different instars. The functions and regulatory mechanism of BmCDA7, however, need further investigation.

  10. Electrospun chitosan-based nanocomposite mats reinforced with chitin nanocrystals for wound dressing.

    Science.gov (United States)

    Naseri, Narges; Algan, Constance; Jacobs, Valencia; John, Maya; Oksman, Kristiina; Mathew, Aji P

    2014-08-30

    The aim of this study was to develop electrospun chitosan/polyethylene oxide-based randomly oriented fiber mats reinforced with chitin nanocrystals (ChNC) for wound dressing. Microscopy studies showed porous mats of smooth and beadless fibers with diameters between 223 and 966 nm. The addition of chitin nanocrystals as well as crosslinking had a positive impact on the mechanical properties of the mats, and the crosslinked nanocomposite mats with a tensile strength of 64.9 MPa and modulus of 10.2 GPa were considered the best candidate for wound dressing application. The high surface area of the mats (35 m(2)g(-1)) was also considered beneficial for wound healing. The water vapor transmission rate of the prepared mats was between 1290 and 1,548 gm(-2)day(-1), and was in the range for injured skin or wounds. The electrospun fiber mats showed compatibility toward adipose derived stem cells, further confirming their potential use as wound dressing materials. PMID:24815394

  11. Distribution of chitin/chitosan-like bioflocculant-producing potential in the genus Citrobacter.

    Science.gov (United States)

    Kimura, Kazuyuki; Inoue, Takuya; Kato, Dai-Ichiro; Negoro, Seiji; Ike, Michihiko; Takeo, Masahiro

    2013-11-01

    Some strains belonging to the genera Citrobacter and Enterobacter have been reported to produce chitin/chitosan-like bioflocculants (BFs) from acetate. In this study, to investigate the distribution of the BF-producing potential in the genus Citrobacter and to screen stably and highly BF-producing strains, we obtained 36 Citrobacter strains from different culture collection centers, which were distributed among seven species in the genus, and tested for the flocculating activities of their culture supernatants using a kaolin suspension method. As a result, 21 strains belonging to C. freundii (17 strains in 23 strains tested), C. braakii (two in two), C. youngae (one in one), and C. werkmanii (one in two) showed flocculating activity, but this ability was limited to cells grown on acetate. Gas chromatography/mass spectrometry (GC/MS) analysis of the hydrolysates from the BFs of five selected strains indicated that they consisted of glucosamine and/or N-acetylglucosamine, such as the chitin/chitosan-like BF (BF04) produced by Citrobacter sp. TKF04 (Fujita et al. J Biosci Bioeng 89: 40-46, 2000). Gel filtration chromatography using a high-performance liquid chromatography system revealed that the molecular weight ranges of these BFs varied, but the average sizes were all above 1.66 × 10⁶Da.

  12. The chitin-binding Cladosporium fulvum effector protein Avr4 is a virulence factor.

    Science.gov (United States)

    van Esse, H Peter; Bolton, Melvin D; Stergiopoulos, Ioannis; de Wit, Pierre J G M; Thomma, Bart P H J

    2007-09-01

    The biotrophic fungal pathogen Cladosporium fulvum (syn. Passalora fulva) is the causal agent of tomato leaf mold. The Avr4 protein belongs to a set of effectors that is secreted by C. fulvum during infection and is thought to play a role in pathogen virulence. Previous studies have shown that Avr4 binds to chitin present in fungal cell walls and that, through this binding, Avr4 can protect these cell walls against hydrolysis by plant chitinases. In this study, we demonstrate that Avr4 expression in Arabidopsis results in increased virulence of several fungal pathogens with exposed chitin in their cell walls, whereas the virulence of a bacterium and an oomycete remained unaltered. Heterologous expression of Avr4 in tomato increased the virulence of Fusarium oxysporum f. sp. lycopersici. Through tomato GeneChip analyses, we demonstrate that Avr4 expression in tomato results in the induced expression of only a few genes. Finally, we demonstrate that silencing of the Avr4 gene in C. fulvum decreases its virulence on tomato. This is the first report on the intrinsic function of a fungal avirulence protein that has a counter-defensive activity required for full virulence of the pathogen.

  13. High prevalence of chitotriosidase deficiency in Peruvian Amerindians exposed to chitin-bearing food and enteroparasites

    Science.gov (United States)

    Manno, N.; Sherratt, S.; Boaretto, F.; Coico, F. Mejìa; Camus, C. Espinoza; Campos, C. Jara; Musumeci, S.; Battisti, A.; Quinnell, R.J.; León, J. Mostacero; Vazza, G.; Mostacciuolo, M.L.; Paoletti, M.G.; Falcone, F.H.

    2014-01-01

    The human genome encodes a gene for an enzymatically active chitinase (CHIT1) located in a single copy on Chromosome 1, which is highly expressed by activated macrophages and in other cells of the innate immune response. Several dysfunctional mutations are known in CHIT1, including a 24-bp duplication in Exon 10 causing catalytic deficiency. This duplication is a common variant conserved in many human populations, except in West and South Africans. Thus it has been proposed that human migration out of Africa and the consequent reduction of exposure to chitin from environmental factors may have enabled the conservation of dysfunctional mutations in human chitinases. Our data obtained from 85 indigenous Amerindians from Peru, representative of populations characterized by high prevalence of chitin-bearing enteroparasites and intense entomophagy, reveal a very high frequency of the 24-bp duplication (47.06%), and of other single nucleotide polymorphisms which are known to partially affect enzymatic activity (G102S: 42.7% and A442G/V: 25.5%). Our finding is in line with a founder effect, but appears to confute our previous hypothesis of a protective role against parasite infection and sustains the discussion on the redundancy of chitinolytic function. PMID:25256524

  14. Laboratory evaluation of five chitin synthesis inhibitors against the colorado potato beetle, Leptinotarsa decemlineata.

    Science.gov (United States)

    Karimzadeh, R; Hejazi, M J; Rahimzadeh Khoei, F; Moghaddam, M

    2007-01-01

    Results of laboratory experiments are reported that tested the effects of five chitin synthesis inhibitors, diflubenzuron, cyromazine, lufenuron, hexaflumuron and triflumuron. on second instars of the Colorado potato beetle, Leptinotarsa decemlineata (Say) (Coleoptera: Crysomelidae), originally collected from potato fields of Bostanabaad, a town 66 km southeast of Tabriz, Iran. In bioassays, the larvae were fed potato leaves dipped in aqueous solutions containing chitin synthesis inhibitors. The mortalities and abnormalities of the treated larvae were recorded 72 hours after treatments. LC(50) values were 58.6, 69.6, 27.3, 0.79 and 81.4 mg ai/ L for diflubenzuron, cyromazine, lufenuron, hexaflumuron and triflumuron, respectively. Compared with phosalone, which is one of the common insecticides used for controlling this pest in Iran, lufenuron and hexaflumuron seem to be much more potent, and if they perform equally well in the field, they would be suitable candidates to be considered as reduced risk insecticides in management programs for L. decemlineata due to much wider margin of safety for mammals and considerably fewer undesirable environmental side effects. PMID:20345285

  15. Sexual Dichromatism of the Damselfly Calopteryx japonica Caused by a Melanin-Chitin Multilayer in the Male Wing Veins

    NARCIS (Netherlands)

    Stavenga, Doekele G.; Leertouwer, Hein L.; Hariyama, Takahiko; De Raedt, Hans A.; Wilts, Bodo D.; Zeil, Jochen

    2012-01-01

    Mature male Calopteryx japonica damselflies have dark-blue wings, due to darkly coloured wing membranes and blue reflecting veins. The membranes contain a high melanin concentration and the veins have a multilayer of melanin and chitin. Female and immature C. japonica damselflies have brown wings. W

  16. Effector-mediated suppression of chitin-triggered immunity by Magnaporthe oryzae is necessary for rice blast disease

    NARCIS (Netherlands)

    Mentlak, T.A.; Kombrink, A.; Shinya, T.; Ryder, L.S.; Otomo, I.; Saitoh, H.; Terauchi, R.; Nishizawa, Y.; Shibuya, N.; Thomma, B.P.H.J.; Talbot, N.J.

    2012-01-01

    Plants use pattern recognition receptors to defend themselves from microbial pathogens. These receptors recognize pathogen-associated molecular patterns (PAMPs) and activate signaling pathways that lead to immunity. In rice (Oryza sativa), the chitin elicitor binding protein (CEBiP) recognizes chiti

  17. Population bulk segregant mapping uncovers resistance mutations and the mode of action of a chitin synthesis inhibitor in arthropods

    NARCIS (Netherlands)

    T. Van Leeuwen; P. Demaeght; E.J. Osborne; W. Dermauw; S. Gohlke; R. Nauen; M. Grbić; L. Tirry; H. Merzendorfer; R.M. Clark

    2012-01-01

    Because of its importance to the arthropod exoskeleton, chitin biogenesis is an attractive target for pest control. This point is demonstrated by the economically important benzoylurea compounds that are in wide use as highly specific agents to control insect populations. Nevertheless, the target si

  18. The role of pH, temperature and nucleation in the formation of cholesteric liquid crystal spherulites from chitin and chitosan.

    Science.gov (United States)

    Murray, S B; Neville, A C

    1998-04-01

    The alpha chitin and chitosan used in the experiments came from crab shell waste (Sigma). This was treated to form a colloidal suspension of chitin or chitosan crystallites. The electrostatic 'charge coat' surrounding the chitin was then manipulated. This was achieved by alteration of the pH of the chitin or chitosan colloid (Chitin pKa = 6.1). This allowed the charge density on the crystalline rod of chitin or chitosan to be altered. The effect of this treatment was ascertained by measuring the diameter of spherulites formed in vitro. The results were analysed to see if the experimental optimal pH agreed with theoretical approximations. Further investigations were carried out on the initiation of the spherulites and the effect of temperature on spherulite formation. The spherulites form via self assembly through a liquid crystalline cholesteric phase. Manipulation of the electrostatic coat of the chitin could be a method of cellular remote control for formation of the helicoid in arthropod cuticle. This would allow the arthropods to set up conditions that aid the self assembly process.

  19. X-Ray Crystal Structure of the Full Length Human Chitotriosidase (CHIT1 Reveals Features of Its Chitin Binding Domain.

    Directory of Open Access Journals (Sweden)

    Firas Fadel

    Full Text Available Chitinases are enzymes that catalyze the hydrolysis of chitin. Human chitotriosidase (CHIT1 is one of the two active human chitinases, involved in the innate immune response and highly expressed in a variety of diseases. CHIT1 is composed of a catalytic domain linked by a hinge to its chitin binding domain (ChBD. This latter domain belongs to the carbohydrate-binding module family 14 (CBM14 family and facilitates binding to chitin. So far, the available crystal structures of the human chitinase CHIT1 and the Acidic Mammalian Chitinase (AMCase comprise only their catalytic domain. Here, we report a crystallization strategy combining cross-seeding and micro-seeding cycles which allowed us to obtain the first crystal structure of the full length CHIT1 (CHIT1-FL at 1.95 Å resolution. The CHIT1 chitin binding domain (ChBDCHIT1 structure shows a distorted β-sandwich 3D fold, typical of CBM14 family members. Accordingly, ChBDCHIT1 presents six conserved cysteine residues forming three disulfide bridges and several exposed aromatic residues that probably are involved in chitin binding, including the highly conserved Trp465 in a surface- exposed conformation. Furthermore, ChBDCHIT1 presents a positively charged surface which may be involved in electrostatic interactions. Our data highlight the strong structural conservation of CBM14 family members and uncover the structural similarity between the human ChBDCHIT1, tachycitin and house mite dust allergens. Overall, our new CHIT1-FL structure, determined with an adapted crystallization approach, is one of the few complete bi-modular chitinase structures available and reveals the structural features of a human CBM14 domain.

  20. Homogeneous synthesis of quaternized chitin in NaOH/urea aqueous solution as a potential gene vector.

    Science.gov (United States)

    Peng, Na; Ai, Ziye; Fang, Zehong; Wang, Yanfeng; Xia, Zhiping; Zhong, Zibiao; Fan, Xiaoli; Ye, Qifa

    2016-10-01

    Water-soluble quaternized chitins (QCs) were homogeneously synthesized by reacting chitin with (3-chloro-2-hydroxypropyl) trimethylammonium chloride (CHPTAC) in 8wt% NaOH/4wt% urea aqueous solutions. The chemical structure and solution properties of the quaternized chitins were characterized by (1)H NMR, FT-IR, elemental analysis, dynamic light scattering (DLS) and zeta potential measurements. The results demonstrated that the water-soluble QCs, with a degree of substitution (DS) values of 0.27-0.54, could be obtained by varying the concentration of chitin, the molar ratio of CHPTAC to chitin unit, and the reaction time at room temperature (25°C). Two QCs (DS=0.36 and 0.54) were selected and studied as gene carriers. Agarose gel retardation assay revealed that both QCs could condense DNA efficiently when N/P ratio>3. The results of particle size and zeta potential indicated that both QCs had a good ability of condensing plasmid DNA into compact nanoparticles with the size of 100-200nm and zeta potential of +18 to +36mV. Compared to polyethylenimine (PEI, 25kDa), the QCs exhibited outstanding low cytotoxicity. Transfection efficiencies of the QCs/DNA complexes were measured using pGL-3 encoding luciferase as the foreign DNA, and the QCs/DNA complexes showed effective transfection efficiencies in 293T cells. These results revealed that the QCs prepared in NaOH/urea aqueous solutions could be used as promising non-viral gene carriers owing to their excellent characteristics. PMID:27312628

  1. X-Ray Crystal Structure of the Full Length Human Chitotriosidase (CHIT1) Reveals Features of Its Chitin Binding Domain

    Science.gov (United States)

    Fadel, Firas; Zhao, Yuguang; Cousido-Siah, Alexandra; Ruiz, Francesc X.; Mitschler, André; Podjarny, Alberto

    2016-01-01

    Chitinases are enzymes that catalyze the hydrolysis of chitin. Human chitotriosidase (CHIT1) is one of the two active human chitinases, involved in the innate immune response and highly expressed in a variety of diseases. CHIT1 is composed of a catalytic domain linked by a hinge to its chitin binding domain (ChBD). This latter domain belongs to the carbohydrate-binding module family 14 (CBM14 family) and facilitates binding to chitin. So far, the available crystal structures of the human chitinase CHIT1 and the Acidic Mammalian Chitinase (AMCase) comprise only their catalytic domain. Here, we report a crystallization strategy combining cross-seeding and micro-seeding cycles which allowed us to obtain the first crystal structure of the full length CHIT1 (CHIT1-FL) at 1.95 Å resolution. The CHIT1 chitin binding domain (ChBDCHIT1) structure shows a distorted β-sandwich 3D fold, typical of CBM14 family members. Accordingly, ChBDCHIT1 presents six conserved cysteine residues forming three disulfide bridges and several exposed aromatic residues that probably are involved in chitin binding, including the highly conserved Trp465 in a surface- exposed conformation. Furthermore, ChBDCHIT1 presents a positively charged surface which may be involved in electrostatic interactions. Our data highlight the strong structural conservation of CBM14 family members and uncover the structural similarity between the human ChBDCHIT1, tachycitin and house mite dust allergens. Overall, our new CHIT1-FL structure, determined with an adapted crystallization approach, is one of the few complete bi-modular chitinase structures available and reveals the structural features of a human CBM14 domain. PMID:27111557

  2. Chitin Mixed in Potting Soil Alters Lettuce Growth, the Survival of Zoonotic Bacteria on the Leaves and Associated Rhizosphere Microbiology.

    Science.gov (United States)

    Debode, Jane; De Tender, Caroline; Soltaninejad, Saman; Van Malderghem, Cinzia; Haegeman, Annelies; Van der Linden, Inge; Cottyn, Bart; Heyndrickx, Marc; Maes, Martine

    2016-01-01

    Chitin is a promising soil amendment for improving soil quality, plant growth, and plant resilience. The objectives of this study were twofold. First, to study the effect of chitin mixed in potting soil on lettuce growth and on the survival of two zoonotic bacterial pathogens, Escherichia coli O157:H7 and Salmonella enterica on the lettuce leaves. Second, to assess the related changes in the microbial lettuce rhizosphere, using phospholipid fatty acid (PLFA) analysis and amplicon sequencing of a bacterial 16S rRNA gene fragment and the fungal ITS2. As a result of chitin addition, lettuce fresh yield weight was significantly increased. S. enterica survival in the lettuce phyllosphere was significantly reduced. The E. coli O157:H7 survival was also lowered, but not significantly. Moreover, significant changes were observed in the bacterial and fungal community of the lettuce rhizosphere. PLFA analysis showed a significant increase in fungal and bacterial biomass. Amplicon sequencing showed no increase in fungal and bacterial biodiversity, but relative abundances of the bacterial phyla Acidobacteria, Verrucomicrobia, Actinobacteria, Bacteroidetes, and Proteobacteria and the fungal phyla Ascomycota, Basidiomycota, and Zygomycota were significantly changed. More specifically, a more than 10-fold increase was observed for operational taxonomic units belonging to the bacterial genera Cellvibrio, Pedobacter, Dyadobacter, and Streptomyces and to the fungal genera Lecanicillium and Mortierella. These genera include several species previously reported to be involved in biocontrol, plant growth promotion, the nitrogen cycle and chitin degradation. These results enhance the understanding of the response of the rhizosphere microbiome to chitin amendment. Moreover, this is the first study to investigate the use of soil amendments to control the survival of S. enterica on plant leaves. PMID:27148242

  3. Chitin and L(+)-lactic acid production from crab (Callinectes bellicosus) wastes by fermentation of Lactobacillus sp. B2 using sugar cane molasses as carbon source.

    Science.gov (United States)

    Flores-Albino, Belem; Arias, Ladislao; Gómez, Jorge; Castillo, Alberto; Gimeno, Miquel; Shirai, Keiko

    2012-09-01

    Crab wastes are employed for simultaneous production of chitin and L(+)-lactic acid by submerged fermentation of Lactobacillus sp. B2 using sugar cane molasses as carbon source. Response surface methodology was applied to design the culture media considering demineralization. Fermentations in stirred tank reactor (2L) using selected conditions produced 88% demineralization and 56% deproteinization with 34% yield of chitin and 19.5 gL(-1) of lactic acid (77% yield). The chitin purified from fermentation displayed 95% degree of acetylation and 0.81 and 1 ± 0.125% of residual ash and protein contents, respectively. PMID:22367529

  4. Exposure to Diflubenzuron Results in an Up-Regulation of a Chitin Synthase 1 Gene in Citrus Red Mite, Panonychus citri (Acari: Tetranychidae)

    OpenAIRE

    Wen-Kai Xia; Tian-Bo Ding; Jin-Zhi Niu; Chong-Yu Liao; Rui Zhong; Wen-Jia Yang; Bin Liu; Wei Dou; Jin-Jun Wang

    2014-01-01

    Chitin synthase synthesizes chitin, which is critical for the arthropod exoskeleton. In this study, we cloned the cDNA sequences of a chitin synthase 1 gene, PcCHS1, in the citrus red mite, Panonychus citri (McGregor), which is one of the most economically important pests of citrus worldwide. The full-length cDNA of PcCHS1 contains an open reading frame of 4605 bp of nucleotides, which encodes a protein of 1535 amino acid residues with a predicted molecular mass of 175.0 kDa. A phylogenetic ...

  5. Self-assembled cardanol azo derivatives as antifungal agent with chitin-binding ability.

    Science.gov (United States)

    Mahata, Denial; Mandal, Santi M; Bharti, Rashmi; Gupta, Vinay Krishna; Mandal, Mahitosh; Nag, Ahindra; Nando, Golok B

    2014-08-01

    Cardanol is a non-isoprenoic phenolic lipid-mixture of distilled cashew nut shell liquid obtained from Anacardium occidentale. Herein, cardanol is purified from cashew nut shell liquid (CNSL) and synthesized to new compounds with different azo amphiphiles. These synthesized compounds are allowed to self-assembled in hydrophobic environment and checked antifungal activity against Candida albicans. Self-assembled structure of CABA showed higher antifungal activity (16μg/mL) and chitin-binding ability in comparison to CAP and CANB. Furthermore, the self-assembled azo amphiphiles are immobilized with silver ions to prepare hydrogel which showed eight folds enhanced antifungal activity. Toxicity is reduced by several folds of self-assembled or hydrogel structure in comparison to pure compounds. Thus, the self-assembled structure of amphiphiles and their hydrogels have been found to be new macromolecules of interest with potential use as antifungal drugs. PMID:24836571

  6. Effect of deletion of chitin synthase genes on mycelial morphology and culture viscosity in Aspergillus oryzae.

    Science.gov (United States)

    Müller, Christian; Hansen, Kim; Szabo, Peter; Nielsen, Jens

    2003-03-01

    The objective of this study was to quantify the effect of disrupting two chitin synthases, chsB and csmA, on the morphology and rheology during batch cultivation of Aspergillus oryzae. The rheological properties were characterized in batch cultivations at different biomass concentrations (from 3.4-22.5 g kg(-1) biomass) and the power-law model adequately described the rheological properties. In the cultivations there were pellets, clumps, and freely dispersed hyphal elements. The different morphological fractions were quantified using image analysis. The apparent viscosity of the fermentation broth was significantly affected by the biomass concentration, the morphology, and also by pH. The chsB disruption strain had lower consistency index K values for all biomass concentrations investigated, which is a desirable trait for industrial Aspergillus fermentations. PMID:12514801

  7. Laboratory evaluation of Flurox, a chitin synthesis inhibitor, on the termite, Microcerotermes diversus.

    Science.gov (United States)

    Habibpour, Behzad

    2010-01-01

    Microcerotermes diversus (Silvestri) (Isoptera: Termitidae) is the most economically destructive termite in structures in southwest Iran. One sustainable control strategy that usually helps to reduce subterranean termite damage in buildings, is the use of insect growth regualtors in a suitable bait matrix that are safe to the user and the environment. In the laboratory assays described here, the delayed toxicity of Flurox, a chitin synthesis inhibitor, to M. diversus was evaluated under force-feeding and choice trials. Flurox induced worker and nymph mortality and incomplete ecdysis in nymphs of M. diversus under no-choice and two-choice feeding tests. These adverse effects may cause disruption of the caste balance in M. diversus, leading to the collapse of the colony. These assays determined concentrations of Flurox that can be used in bait formulations.

  8. Effects of chitin nano-whiskers on the gelatinization and retrogradation of maize and potato starches.

    Science.gov (United States)

    Ji, Na; Liu, Chengzhen; Zhang, Shuangling; Yu, Jing; Xiong, Liu; Sun, Qingjie

    2017-01-01

    Starch is very prone to retrogradation after gelatinization. Inhibition of starch retrogradation has been an important factor in improving the quality of food. For the first time, we investigated the effect of nano-materials, represented by chitin nano-whiskers (CNWs), on the short- and long-term retrogradation of maize and potato starches. Rapid Visco-Analyser results showed that the addition of CNWs significantly decreased the setback values of maize and potato starches, which suggested that CNWs could retard the short-term retrogradation of starch. Differential scanning calorimetry and X-ray diffraction results showed that the percentage of retrogradation of maize and potato starches significantly decreased (P<0.05), suggesting the inhibition of long-term retrogradation. The CNWs could be used as a new inhibitor of starch retrogradation to develop starch-based food with longer shelf life. PMID:27507508

  9. Synthesis and Characterization of a Novel Liquid Crystalline Chitin--Quaternary Ammonium Chitosan Salt

    Institute of Scientific and Technical Information of China (English)

    RUAN Yong-hong; DONG Yan-ming; WU Ming-shui; ZENG Man-qing; WANG Shui-ju

    2003-01-01

    N-Butyl chitosan(NBCS) derivatives were prepared by introducing butyl groups into the amine groups of chitosan via Schiff base intermediates. The quaternization of NBCS was carried out by using ethyl iodide to produce water-soluble cationic polyelectrolytes. The degree of the substitution of the products was measured by means of the electron spectroscopy for a successful chemical analysis. The quaternary ammonium chitosan salt(QACS) was proved to be a novel cholesteric liquid crystalline chitin, by means of the polarized optical microscopy and the circular dichroism spectropolarimetry. The critical mass fraction of the QACS/formic acid solution forming a lyotropic liquid crystal phase was 50%, which was almost the same as that of the NBCS/formic acid solution, but much higher than that of the chitosan in the same solvent.

  10. Optimized production of Serratia marcescens B742 mutants for preparing chitin from shrimp shells powders.

    Science.gov (United States)

    Zhang, Hongcai; Fang, Jiyang; Deng, Yun; Zhao, Yanyun

    2014-08-01

    To improve the deproteinization (DP) efficacy of shrimp shell powders (SSP) for preparing chitin, Serratia marcescens B742 mutants were prepared using 2% diethyl sulfate (DES), UV-irradiation, and/or microwave heating treatments. Both single-stage and multi-stage mutations were investigated for optimizing S. marcescens B742 mutation conditions. Under the optimized mutation conditions (2% DES treatment for 30min plus successive 20min UV-irradiation), the protease and chitosanase activity produced by mutant S. marcescens B742 was 240.15 and 170.6mU/mL, respectively, as compared with 212.58±1.51 and 83.75±6.51mU/mL, respectively, by wild S. marcescens B742. DP efficacy of SSP by mutant S. marcescens B742 reached 91.4±4.6% after 3d of submerged fermentation instead of 83.4±4.7% from the wild S. marcescens B742 after 4d of submerged fermentation. Molecular mass of chitosanase and protease was 41.20 and 47.10kDa, respectively, and both enzymes were verified by mass spectrometry analysis. The chitosanase from both wild and mutant S. marcescens B742 was activated by sodium dodecyl sulfate (SDS), Tween 20, Tween 40, and Triton-100, and the protease and chitosanase were strongly inhibited by ethylenediaminetetraacetic acid (EDTA). These results suggested that S. marcescens B742 mutants can be used in the biological production of chitin through deproteinization of SSP.

  11. IDENTIFICATION AND HORMONE INDUCTION OF PUTATIVE CHITIN SYNTHASE GENES AND SPLICE VARIANTS IN Leptinotarsa decemlineata (SAY).

    Science.gov (United States)

    Shi, Ji-Feng; Mu, Li-Li; Guo, Wen-Chao; Li, Guo-Qing

    2016-08-01

    Chitin synthase (ChS) plays a critical role in chitin synthesis and excretion. In this study, two ChS genes (LdChSA and LdChSB) were identified in Leptinotarsa decemlineata. LdChSA contains two splicing variants, LdChSAa and LdChSAb. Within the first, second, and third larval instars, the mRNA levels of LdChSAa, LdChSAb, and LdChSB coincide with the peaks of circulating 20-hydroxyecdysone (20E) and juvenile hormone (JH). In vitro culture of midguts and an in vivo bioassay revealed that 20E and an ecdysteroid agonist halofenozide stimulated the expression of the three LdChSs. Conversely, a reduction of 20E by RNA interference (RNAi) of an ecdysteroidogenesis gene LdSHD repressed the expression of these LdChSs, and ingestion of halofenozide by LdSHD RNAi larvae rescued the repression. Moreover, disruption of 20E signaling by RNAi of LdEcR, LdE75, LdHR3, and LdFTZ-F1 reduced the expression levels of these genes. Similarly, in vitro culture and an in vivo bioassay showed that exogenous JH and a JH analog methoprene activated the expression of the three LdChSs, whereas a decrease in JH by RNAi of a JH biosynthesis gene LdJHAMT downregulated these LdChSs. It seems that JH upregulates LdChSs at the early stage of each instar, whereas a 20E pulse triggers the transcription of LdChSs during molting in L. decemlineata. PMID:27030662

  12. The use of DSC curves to determine the acetylation deg.ree of chitin/chitosan samples

    International Nuclear Information System (INIS)

    The use of DSC curves is proposed as an alternative method to determine the deg.ree of N-acetylation (DA) in chitin/chitosan samples, based in both peak area and height of the decomposition signal. Samples with DA from 74 to 16% were prepared from a chitin commercial sample and the DA was determined by 1H NMR, 13C CP/MAS NMR and IR spectra. The effect of water content, heating rate, sample mass and gas flow on the DSC peaks were evaluated and optimized. Using optimized conditions a linear relationship between peak area and height with the DA could be achieved with linear correlation coefficients of -0.998 and -0.999 (n = 7), respectively. The calibration graphs were used to determine the DA of a commercial chitosan sample with relative errors ranging from 2 to 3% for both peak area and peak height, when compared with the DA determined by 1H NMR method

  13. Application of chitin and chitosan extracted from silkworm chrysalides in the treatment of textile effluents contaminated with remazol dyes

    Directory of Open Access Journals (Sweden)

    Julliana Isabelle Simionato

    2014-09-01

    Full Text Available Chitin extracted from silkworm chrysalides was used to prepare chitosan applied in this investigation. Adsorption studies were carried out in column and in aqueous suspension with two dyes, blue remazol (RN and black remazol 5 (RB. The study showed that adsorption is better in the chitosan-packed column than in the chitin-packed one. However, the comparison of the adsorption in column and in suspension revealed better results for the latter. The plotted Langmuir isotherm did not indicate significant difference in the theoretical capacity of saturation of the monolayer (Qo for either dye. The application of the adsorption process to actual conditions was evaluated by adsorption assays of actual textile effluents. In acid pH, chitosan adsorbed the dyes responsible for the effluent coloration completely. This study showed that the use of chitosan obtained from silkworm chrysalides is a viable alternative for the immobilization of dyes in textile industry effluents.

  14. Chitin nanofibrils suppress skin inflammation in atopic dermatitis-like skin lesions in NC/Nga mice.

    Science.gov (United States)

    Izumi, Ryotaro; Azuma, Kazuo; Izawa, Hironori; Morimoto, Minoru; Nagashima, Masaaki; Osaki, Tomohiro; Tsuka, Takeshi; Imagawa, Tomohiro; Ito, Norihiko; Okamoto, Yoshiharu; Saimoto, Hiroyuki; Ifuku, Shinsuke

    2016-08-01

    We evaluated the effect of chitin nanofibril (CNF) application via skin swabs on an experimental atopic dermatitis (AD) model. AD scores were lower, and hypertrophy and hyperkeratosis of the epidermis were suppressed after CNF treatment. Furthermore, inflammatory cell infiltration in both the epidermis and dermis was inhibited. CNFs also attenuated histological scores. The suppressive effects of CNFs were equal to those of corticosteroid application; however, chitin did not show these effects. CNF application might have anti-infllammatory effects via suppression of the activation of nuclear factor-kappa B, cyclooxygenase-2, and inducible nitric oxide synthase. In an early-stage model of experimental AD, CNFs suppressed AD progression to the same extent as corticosteroids. They also suppressed skin inflammation and IgE serum levels. Our findings indicate that CNF application could aid in the prevention or treatment of AD skin lesions. PMID:27112880

  15. Physico-Chemical Characteristics and Functional Properties of Chitin and Chitosan Produced by Mucor circinelloides Using Yam Bean as Substrate

    Directory of Open Access Journals (Sweden)

    Marta C. Freitas da Silva

    2011-08-01

    Full Text Available Microbiological processes were used for chitin and chitosan production by Mucor circinelloides (UCP 050 grown in yam bean (Pachyrhizus erosus L. Urban medium. The polysaccharides were extracted by alkali–acid treatment and structural investigations by X-ray diffraction, Fourier transform IR analysis, viscosity and thermal analysis by TG, DTG, and DTA were done. The highest biomass yield (20.7 g/L was obtained at 96 hours. The highest levels of chitosan (64 mg/g and chitin (500 mg/g were produced at 48 and 72 hours, respectively. It was demonstrated that yam bean shows great potential as an economic medium and it is possible to achieve a good yield of chitosan with chemical properties that enable its use in biotechnological applications.

  16. Immobilization of Papain on Chitin and Chitosan and Recycling of Soluble Enzyme for Deflocculation of Saccharomyces cerevisiae from Bioethanol Distilleries

    OpenAIRE

    Douglas Fernandes Silva; Henrique Rosa; Ana Flavia Azevedo Carvalho; Pedro de Oliva-Neto

    2015-01-01

    Yeast flocculation (Saccharomyces cerevisiae) is one of the most important problems in fuel ethanol production. Yeast flocculation causes operational difficulties and increase in the ethanol cost. Proteolytic enzymes can solve this problem since it does not depend on these changes. The recycling of soluble papain and the immobilization of this enzyme on chitin or chitosan were studied. Some cross-linking agents were evaluated in the action of proteolytic activity of papain. The glutaraldehyde...

  17. The bifunctional plant receptor, OsCERK1, regulates both chitin-triggered immunity and arbuscular mycorrhizal symbiosis in rice.

    Science.gov (United States)

    Miyata, Kana; Kozaki, Toshinori; Kouzai, Yusuke; Ozawa, Kenjirou; Ishii, Kazuo; Asamizu, Erika; Okabe, Yoshihiro; Umehara, Yosuke; Miyamoto, Ayano; Kobae, Yoshihiro; Akiyama, Kohki; Kaku, Hanae; Nishizawa, Yoko; Shibuya, Naoto; Nakagawa, Tomomi

    2014-11-01

    Plants are constantly exposed to threats from pathogenic microbes and thus developed an innate immune system to protect themselves. On the other hand, many plants also have the ability to establish endosymbiosis with beneficial microbes such as arbuscular mycorrhizal (AM) fungi or rhizobial bacteria, which improves the growth of host plants. How plants evolved these systems managing such opposite plant-microbe interactions is unclear. We show here that knockout (KO) mutants of OsCERK1, a rice receptor kinase essential for chitin signaling, were impaired not only for chitin-triggered defense responses but also for AM symbiosis, indicating the bifunctionality of OsCERK1 in defense and symbiosis. On the other hand, a KO mutant of OsCEBiP, which forms a receptor complex with OsCERK1 and is essential for chitin-triggered immunity, established mycorrhizal symbiosis normally. Therefore, OsCERK1 but not chitin-triggered immunity is required for AM symbiosis. Furthermore, experiments with chimeric receptors showed that the kinase domains of OsCERK1 and homologs from non-leguminous, mycorrhizal plants could trigger nodulation signaling in legume-rhizobium interactions as the kinase domain of Nod factor receptor1 (NFR1), which is essential for triggering the nodulation program in leguminous plants, did. Because leguminous plants are believed to have developed the rhizobial symbiosis on the basis of AM symbiosis, our results suggest that the symbiotic function of ancestral CERK1 in AM symbiosis enabled the molecular evolution to leguminous NFR1 and resulted in the establishment of legume-rhizobia symbiosis. These results also suggest that OsCERK1 and homologs serve as a molecular switch that activates defense or symbiotic responses depending on the infecting microbes. PMID:25231970

  18. Effect of triflumuron, a chitin synthesis inhibitor, on Aedes aegypti, Aedes albopictus and Culex quinquefasciatus under laboratory conditions

    OpenAIRE

    Belinato, Thiago Affonso; Martins, Ademir Jesus; Lima, José Bento Pereira; Valle, Denise

    2013-01-01

    Background Resistance to traditional insecticides represents a threat to the control of disease vectors. The insect growth regulators (IGR) are a potential alternative to control mosquitoes, including resistant populations. The chitin synthesis inhibitors (CSI) are IGRs, which interfere with the insect molting process and represent one major class of compounds against Aedes aegypti populations resistant to the larvicide organophosphate temephos. In the present study, we evaluated the efficacy...

  19. The efficacy of a chitin synthesis inhibitor against field populations of organophosphate-resistant Aedes aegypti in Brazil

    OpenAIRE

    Nathalia Giglio Fontoura; Diogo Fernandes Bellinato; Denise Valle; José Bento Pereira Lima

    2012-01-01

    The mosquito Aedes aegypti is the main focus of dengue control campaigns. Because of widespread resistance against conventional chemical insecticides, chitin synthesis inhibitors (CSIs) are considered control alternatives. We evaluated the resistance status of four Brazilian Ae. aegypti populations to both the organophosphate temephos and the pyrethroid deltamethrin, which are used in Brazil to control larvae and adults, respectively. All vector populations exhibited high levels of temephos r...

  20. Comparison of availability of copper(II) complexes with organic ligands to bacterial cells and to chitin

    Energy Technology Data Exchange (ETDEWEB)

    Vasconcelos, M.T.S.D.; Azenha, M.A.O. [Laquipai, Porto (Portugal). Faculdade de Ciencias do Porto; Cabral, J.P.S. [Inst. de Botanica e Centro de Citologia Experimental U.P., Porto (Portugal)

    1997-10-01

    Bacterial cells or chitin were exposed to solutions with 100 {micro}M total but only 5 {micro}M free copper, due to the presence of a proper concentration of proline, lysine, cysteine, or ethylenediamine tetraacetate (EDTA). The influence of the nature and concentration of the particles and soluble ligands, on the sorption and on the desorption of the copper, at pH 6.50 and 25.0 C, was investigated. The metal sorbed by the particles and that left in the solution were measured by atomic absorption spectrometry, after different periods of contact between particles and solution. The interpretation of the results was based on the copper(II) speciation calculated through equilibrium approaches applied to homogeneous or heterogeneous systems. A significant fraction of copper bound to the organic ligands was displaced to the bacteria or chitin, and the extent of chemical reaction depended on the nature of both the soluble (or leaving) ligands and sites on the particle surface (or entering ligands), as expected by the equilibrium theory. But with chitin, the uptake of copper in the presence of cysteine or EDTA was higher than expected, which may be due to the adsorption of the soluble copper complexes on the particle surface. In consequence of a competition between soluble and particulate ligands (cells or chitin), the free copper(II) concentration decreased in the solution, even in the presence of very strong chelators. The results indicate that copper availability is not a simple function of the initial free copper concentration in the solution. Desorption of the previously fixed copper, originated by free soluble ligands indicated that the sorption of copper was quasireversible for both particles, though a larger dismissal of the equilibrium position occurred for the cells, probably due to their biological activity.

  1. Effects of chitin and salicylic acid on biological control activity of Pseudomonas spp. against damping off of pepper

    OpenAIRE

    M.Rajkumar; Lee, K. J.; Freitas, H.

    2008-01-01

    Fluorescent pseudomonads (SE21 and RD41) and resistance inducers (chitin and salicylic acid) were examined for plant growth promotion and biological control of damping off of pepper caused by Rhizoctonia solani. The antagonists SE21 and RD41 isolated from the rhizosphere of pepper were found to be effective in inhibiting the mycelial growth of R. solani in a dual culture assay and increasing the seedling vigour in a roll towel assay. Both antagonists were further characterized for biocontrol ...

  2. Preparation of acrylic acid-modified chitin improved by an experimental design and its application in absorbing toxic organic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Chao-Ming, E-mail: charming@mail.ksu.edu.tw [Department of Materials Engineering, Kun Shan University, Tainan, Taiwan (China); Chen, Lung-Chuan, E-mail: lcchen@mail.ksu.edu.tw [Department of Materials Engineering, Kun Shan University, Tainan, Taiwan (China); Yang, Hui-Chia, E-mail: yang.junkdna@gmail.com [Department of Environmental Engineering, Kun Shan University, Tainan, Taiwan (China); Li, Min-Hsing, E-mail: a1487561a@yahoo.com.tw [Department of Environmental Engineering, Kun Shan University, Tainan, Taiwan (China); Pan, Ting-Chung, E-mail: tcpan@mail.ksu.edu.tw [Department of Environmental Engineering, Kun Shan University, Tainan, Taiwan (China)

    2012-11-30

    Highlights: Black-Right-Pointing-Pointer Acrylic acid-modified chitin. Black-Right-Pointing-Pointer Experimental design. Black-Right-Pointing-Pointer Graft copolymerization. Black-Right-Pointing-Pointer Adsorption of toxic organic compounds. Black-Right-Pointing-Pointer Very high adsorption capacity. - Abstract: Chitin grafted poly (acrylic acid) (chi-g-PAA) is synthesized and characterized as an adsorbent of toxic organic compounds. Chi-g-PAA copolymers are prepared using of ammonium cerium (IV) nitrate (Ce{sup 4+}) as the initiator. The highest grafting percentage of AA in chitin obtained using the traditional technique is 163.1%. A maximum grafting percentage of 230.6% is obtained using central composite design (CCD). Experimental results are consistent with theoretical calculations. The grafted copolymer is characterized by Fourier transform Infrared spectroscopy and solid state {sup 13}C NMR. A representative chi-g-AA copolymer is hydrolyzed to a type of sodium salt (chi-g-PANa) and used in the adsorption of malachite green (MG), methyl violet (MV), and paraquat (PQ) in aqueous. The monolayer adsorption capacities of these substances are 285.7, 357.1, and 322.6 mg/g-adsorbent, respectively. Thermodynamic calculations show that the adsorption of MG, MV, and PQ are more favored at diluted solutions. The high adsorption capacity of chi-g-PANa for toxic matter indicates its potential in the treatment of wastewater and emergency treatment of PQ-poisoned patients.

  3. Fabrication of Chitin/Poly(butylene succinate/Chondroitin Sulfate Nanoparticles Ternary Composite Hydrogel Scaffold for Skin Tissue Engineering

    Directory of Open Access Journals (Sweden)

    S. Deepthi

    2014-12-01

    Full Text Available Skin loss is one of the oldest and still not totally resolved problems in the medical field. Since spontaneous healing of the dermal defects would not occur, the regeneration of full thickness of skin requires skin substitutes. Tissue engineering constructs would provide a three dimensional matrix for the reconstruction of skin tissue and the repair of damage. The aim of the present work is to develop a chitin based scaffold, by blending it with poly(butylene succinate (PBS, an aliphatic, biodegradable and biocompatible synthetic polymer with excellent mechanical properties. The presence of chondroitin sulfate nanoparticles (CSnp in the scaffold would favor cell adhesion. A chitin/PBS/CSnp composite hydrogel scaffold was developed and characterized by SEM (Scanning Electron Microscope, FTIR (Fourier Transform Infrared Spectroscopy, and swelling ratio of scaffolds were analyzed. The scaffolds were evaluated for the suitability for skin tissue engineering application by cytotoxicity, cell attachment, and cell proliferation studies using human dermal fibroblasts (HDF. The cytotoxicity and cell proliferation studies using HDF confirm the suitability of the scaffold for skin regeneration. In short, these results show promising applicability of the developed chitin/PBS/CSnps ternary composite hydrogel scaffolds for skin tissue regeneration.

  4. Synthesis and biological evaluation of novel phosphoramidate derivatives of coumarin as chitin synthase inhibitors and antifungal agents.

    Science.gov (United States)

    Ji, Qinggang; Ge, Zhiqiang; Ge, Zhixing; Chen, Kaizhi; Wu, Hualong; Liu, Xiaofei; Huang, Yanrong; Yuan, Lvjiang; Yang, Xiaolan; Liao, Fei

    2016-01-27

    A series of novel phosphoramidate derivatives of coumarin have been designed and synthesized as chitin synthase (CHS) inhibitors. All the synthesized compounds have been screened for their chitin synthase inhibition activity and antimicrobial activity in vitro. The bioactive assay manifested that most of the target compounds exhibited good efficacy against CHS and a variety of clinically important fungal pathogens. In particular, compound 7t with IC50 of 0.08 mM against CHS displayed stronger efficiency than the reference Polyoxin B with IC50 of 0.16 mM. In addition, the apparent Ki values of compound 7t was 0.096 mM while the Km of Chitin synthase prepared from Candida tropicalis was 3.86 mM for UDP-N-acetylglucosamine, and the result of the Ki showed that the compounds was a non-competitive inhibitor of the CHS. As far as the antifungal activity is concerned, compounds 7o, 7r and 7t were highly active against Aspergillus flavus with MIC values in the range of 1 μg/mL to 2 μg/Ml while the results of antibacterial screening showed that these compounds have negligible actions to the tested bacteria. These results indicated that the design of these compounds as antifungal agents was rational.

  5. The Correlation between Chitin and Acidic Mammalian Chitinase in Animal Models of Allergic Asthma

    Directory of Open Access Journals (Sweden)

    Chia-Rui Shen

    2015-11-01

    Full Text Available Asthma is the result of chronic inflammation of the airways which subsequently results in airway hyper-responsiveness and airflow obstruction. It has been shown that an elicited expression of acidic mammalian chitinase (AMCase may be involved in the pathogenesis of asthma. Our recent study has demonstrated that the specific suppression of elevated AMCase leads to reduced eosinophilia and Th2-mediated immune responses in an ovalbumin (OVA-sensitized mouse model of allergic asthma. In the current study, we show that the elicited expression of AMCase in the lung tissues of both ovalbumin- and Der P2-induced allergic asthma mouse models. The effects of allergic mediated molecules on AMCase expression were evaluated by utilizing promoter assay in the lung cells. In fact, the exposure of chitin, a polymerized sugar and the fundamental component of the major allergen mite and several of the inflammatory mediators, showed significant enhancement on AMCase expression. Such obtained results contribute to the basis of developing a promising therapeutic strategy for asthma by silencing AMCase expression.

  6. Hydroxyapatite-hybridized chitosan/chitin whisker bionanocomposite fibers for bone tissue engineering applications.

    Science.gov (United States)

    Pangon, Autchara; Saesoo, Somsak; Saengkrit, Nattika; Ruktanonchai, Uracha; Intasanta, Varol

    2016-06-25

    Biomimetic nanofibrous scaffolds derived from natural biopolymers for bone tissue engineering applications require good mechanical and biological performances including biomineralization. The present work proposes the utility of chitin whisker (CTWK) to enhance mechanical properties of chitosan/poly(vinyl alcohol) (CS/PVA) nanofibers and to offer osteoblast cell growth with hydroxyapatite (HA) mineralization. By using diacid as a solvent, electrospun CS/PVA nanofibrous membranes containing CTWK can be easily obtained. The dimension stability of nanofibrous CS/PVA/CTWK bionanocomposite is further controlled by exposing to glutaraldehyde vapor. The nanofibrous membranes obtained allow mineralization of HA in concentrated simulated body fluid resulting in an improvement of Young's modulus and tensile strength. The CTWK combined with HA in bionanocomposite is a key to promote osteoblast cell adhesion and proliferation. The present work, for the first time, demonstrates the use of CTWKs for bionanocomposite fibers of chitosan and its hydroxyapatite biomineralization with the function in osteoblast cell culture. These hydroxyapatite-hybridized CS/PVA/CTWK bionanocomposite fibers (CS/PVA/CTWK-HA) offer a great potential for bone tissue engineering applications. PMID:27083834

  7. Novel chitin/chitosan-glucan wound dressing: Isolation, characterization, antibacterial activity and wound healing properties.

    Science.gov (United States)

    Abdel-Mohsen, A M; Jancar, J; Massoud, D; Fohlerova, Z; Elhadidy, H; Spotz, Z; Hebeish, A

    2016-08-20

    Chitin/chitosan-glucan complex (ChCsGC) was isolated from Schizophyllum commune (S. commune) and dissolved for the first time in precooled (-15°C) 8wt.% urea/6wt.% NaOH aqueous solution. Novel nonwoven microfiber mats were fabricated by wet-dry-spinning technique and evaluated the mechanical of fabrics mats and surface morphology. Isolated and nonwoven mat were characterized employing FTIR-ATR, Optical microscope, TGA, DSC, H/C NMR, SEM and XRD techniques. According to the physical/chemical characterization measurements we can assumed that, the net and the novel dressing mats have the same chemical structure with slightly changes in the thermal stability for the dressing mats.The biological activity of the nonwoven ChCsGC fabric was tested against different types of bacteria exhibiting excellent antibacterial activity. Cell viability of the plain complex and nonwovens mats were evaluated utilizing mouse fibroblast cell line varying concentrations and treatment time. ChCsGC did not show any cytotoxicity against mouse fibroblast cells and the cell-fabrics interaction was also investigated using fluorescence microscope. The novel ChCsGC nonwovens exhibited excellent surgical wound healing ability when tested using rat models. PMID:27265311

  8. Effects of chitin nano-whiskers on the antibacterial and physicochemical properties of maize starch films.

    Science.gov (United States)

    Qin, Yang; Zhang, Shuangling; Yu, Jing; Yang, Jie; Xiong, Liu; Sun, Qingjie

    2016-08-20

    We investigated the effects of chitin nano-whiskers (CNWs) on the antibacterial and physiochemical properties of maize starch-based films. The microstructures, crystalline structures, and thermal, mechanical and barrier properties of the nanocomposite films were characterized by using transmission electron microscopy, X-ray diffraction analysis, thermogravimetric, differential scanning calorimeter, and texture profile analysis. The tensile strength of the maize starch films increased from 1.64MPa to 3.69MPa (Preinforcement with up to 1%. The water vapor permeability of the nanocomposite films decreased from 5.32×10(-12) to 2.22×10(-12)gm(-1)s(-1)Pa(-1) with the CNW content increasing from 0% to 2%. The onset temperature, peak temperature and the gelatinization enthalpy of the films containing CNWs were higher than those of the pure starch films. Furthermore, the nanocomposite films exhibited strong antimicrobial activity against Gram-positive Listeria monocytogenes but not against Gram-negative Escherichia coli.

  9. Photothermal and Structural Comparative Analysis of Chitinous Exoskeletons of Marine Invertebrates

    Science.gov (United States)

    Juárez-de la Rosa, B. A.; Yañez-Limón, J. M.; Tiburcio-Moreno, J. A.; Zambrano, M.; Ardisson, P.-L.; Quintana, P.; Alvarado-Gil, J. J.

    2012-11-01

    Chitinous materials are common in nature and provide different functions including protection and support of many invertebrate animals. Exoskeletons in these organisms constitute the boundary regulating interaction between the animal and the external environment. For this reason, it is important to study the physical properties of these skeletons, in particular, thermal properties. The objective of this study is to investigate the thermal diffusivity of the skeletons of four species of marine invertebrates, Antipathes caribbeana (black coral), Panulinus argus (lobster), Callinectes sapidus (crab), and Limulus polyphemus (xiphosure). Thermal characterization is performed using photothermal radiometry (PTR) and laser-flash techniques. The measurements are complemented with structural characterization using X-ray diffraction. The results using both laser flash and PTR are consistent. These indicate that the thermal properties are strongly dependent on the presence of biogenic minerals (calcium and/or magnesium) and on the crystallinity index of the structure. The thermal-diffusivity values show an increase as a function of the crystallinity index.

  10. Halo(natrono)archaea isolated from hypersaline lakes utilize cellulose and chitin as growth substrates

    Science.gov (United States)

    Sorokin, Dimitry Y.; Toshchakov, Stepan V.; Kolganova, Tatyana V.; Kublanov, Ilya V.

    2015-01-01

    Until recently, extremely halophilic euryarchaeota were considered mostly as aerobic heterotrophs utilizing simple organic compounds as growth substrates. Almost nothing is known on the ability of these prokaryotes to utilize complex polysaccharides, such as cellulose, xylan, and chitin. Although few haloarchaeal cellulases and chitinases were recently characterized, the analysis of currently available haloarchaeal genomes deciphered numerous genes-encoding glycosidases of various families including endoglucanases and chitinases. However, all these haloarchaea were isolated and cultivated on simple substrates and their ability to grow on polysaccharides in situ or in vitro is unknown. This study examines several halo(natrono)archaeal strains from geographically distant hypersaline lakes for the ability to grow on insoluble polymers as a sole growth substrate in salt-saturated mineral media. Some of them belonged to known taxa, while other represented novel phylogenetic lineages within the class Halobacteria. All isolates produced extracellular extremely salt-tolerant cellulases or chitinases, either cell-free or cell-bound. Obtained results demonstrate a presence of diverse populations of haloarchaeal cellulo/chitinotrophs in hypersaline habitats indicating that euryarchaea participate in aerobic mineralization of recalcitrant organic polymers in salt-saturated environments. PMID:26441877

  11. Characteristics of deacetylation and depolymerization of β-chitin from jumbo squid (Dosidicus gigas) pens.

    Science.gov (United States)

    Jung, Jooyeoun; Zhao, Yanyun

    2011-09-27

    This study evaluated the deacetylation characteristics of β-chitin from jumbo squid (Dosidicus gigas) pens by using strongly alkaline solutions of NaOH or KOH. Taguchi design was employed to investigate the effect of reagent concentration, temperature, time, and treatment step on molecular mass (MM) and degree of deacetylation (DDA) of the chitosan obtained. The optimal treatment conditions for achieving high MM and DDA of chitosan were identified as: 40% NaOH at 90°C for 6h with three separate steps (2h+2h+2h) or 50% NaOH at 90°C for 6h with one step, or 50% KOH at 90°C for 4h with three steps (1h+1h+2h) or 6h with one step. The most important factor affecting DDA and MM was temperature and time, respectively. The chitosan obtained was then further depolymerized by cellulase or lysozyme with cellulase giving a higher degradation ratio, lower relative viscosity, and a larger amount of reducing-end formations than that of lysozyme due to its higher susceptibility. This study demonstrated that jumbo squid pens are a good source of materials to produce β-chitosan with high DDA and a wide range of MM for various potential applications. PMID:21700271

  12. Chitin-lignin material as a novel matrix for enzyme immobilization.

    Science.gov (United States)

    Zdarta, Jakub; Klapiszewski, Łukasz; Wysokowski, Marcin; Norman, Małgorzata; Kołodziejczak-Radzimska, Agnieszka; Moszyński, Dariusz; Ehrlich, Hermann; Maciejewski, Hieronim; Stelling, Allison L; Jesionowski, Teofil

    2015-04-01

    Innovative materials were made via the combination of chitin and lignin, and the immobilization of lipase from Aspergillus niger. Analysis by techniques including FTIR, XPS and 13C CP MAS NMR confirmed the effective immobilization of the enzyme on the surface of the composite support. The electrokinetic properties of the resulting systems were also determined. Results obtained from elemental analysis and by the Bradford method enabled the determination of optimum parameters for the immobilization process. Based on the hydrolysis reaction of para-nitrophenyl palmitate, a determination was made of the catalytic activity, thermal and pH stability, and reusability. The systems with immobilized enzymes were found to have a hydrolytic activity of 5.72 mU, and increased thermal and pH stability compared with the native lipase. The products were also shown to retain approximately 80% of their initial catalytic activity, even after 20 reaction cycles. The immobilization process, using a cheap, non-toxic matrix of natural origin, leads to systems with potential applications in wastewater remediation processes and in biosensors. PMID:25903282

  13. Effect of the chitin synthesis inhibitor triflumuron on the development, viability and reproduction of Aedes aegypti

    Directory of Open Access Journals (Sweden)

    Thiago Affonso Belinato

    2009-02-01

    Full Text Available The control of Aedes aegypti is impaired due to the development of resistance to chemical insecticides. Insect Growth Regulators (IGR exhibit distinct mechanisms of action and are considered potential vector control alternatives. Studies regarding the effects of sublethal IGR doses on the viability of resulting adults will contribute to eval-uating their impact in the field. We analyzed several aspects of Ae. aegypti adults surviving exposure to a partially lethal dose of triflumuron, a chitin synthesis inhibitor. A highly significant difference in the proportion of males and females was noted in the triflumuron-exposed group (65.0% males compared to the controls (50.2% males. Triflumuron affected adult longevity, particularly for females; after 16 days, only 29.2% of males and 13.8% of females were alive, in contrast with 94% survival of the control mosquitoes. The locomotor activity was reduced and the blood-feeding ability of the treated females was also affected (90.4% and 48.4% of the control and triflumuron-exposed females, respectively, successfully ingested blood. Triflumuron-surviving females ingested roughly 30% less blood and laid 25% fewer eggs than the control females. The treated males and females exhibited a diminished ability to copulate, resulting in less viable eggs.

  14. Efficacy of chitin synthesis inhibitors on nymphal German cockroaches (Dictyoptera: Blattellidae).

    Science.gov (United States)

    DeMark, J J; Bennett, G W

    1989-12-01

    Second- and fifth-instar Blattella germanica (L.), fed the chitin synthesis inhibitors triflumuron, chlorfluazuron, hexafluron, and UC 84572 (structure not disclosed) were examined for mortality and developmental abnormalities. All compounds were active against B. germanica (L.), with lower diet concentrations being required to kill second instars compared with fifth instars. Chlorfluazuron was significantly more active against second and fifth instars (LC50 = 0.000191 and 0.000363% AI, respectively for the second and fifth instars). UC 84572 also killed nymphs at extremely low concentrations (LC50 = 0.000508 and 0.000754% AI, respectively, for second and fifth instars). LC50's for hexafluron and triflumuron against fifth instars were more than 1,000 times higher than that for chlorfluazuron. Sensitive periods of exposure were determined by comparing effects when four different age classes of fifth instars (1-, 4-, 7-, and 10-d old) fed on the compounds for 3 d. Triflumuron was most effective when ingested during the first three age classes and hexafluron was most effective during the last three age classes. Chlorfluazuron and UC 84572 were most effective when ingested during the second age class (days 4-6). Adults surviving exposure during the fifth instar were often deformed and weak; they died at a greater rate than the controls. However, most surviving adults were able to reproduce normally. PMID:2607029

  15. Effect of the chitin synthesis inhibitor triflumuron on the development, viability and reproduction of Aedes aegypti.

    Science.gov (United States)

    Belinato, Thiago Affonso; Martins, Ademir Jesus; Lima, José Bento Pereira; Lima-Camara, Tamara Nunes de; Peixoto, Alexandre Afrânio; Valle, Denise

    2009-02-01

    The control of Aedes aegypti is impaired due to the development of resistance to chemical insecticides. Insect Growth Regulators (IGR) exhibit distinct mechanisms of action and are considered potential vector control alternatives. Studies regarding the effects of sublethal IGR doses on the viability of resulting adults will contribute to eval-uating their impact in the field. We analyzed several aspects of Ae. aegypti adults surviving exposure to a partially lethal dose of triflumuron, a chitin synthesis inhibitor. A highly significant difference in the proportion of males and females was noted in the triflumuron-exposed group (65.0% males) compared to the controls (50.2% males). Triflumuron affected adult longevity, particularly for females; after 16 days, only 29.2% of males and 13.8% of females were alive, in contrast with 94% survival of the control mosquitoes. The locomotor activity was reduced and the blood-feeding ability of the treated females was also affected (90.4% and 48.4% of the control and triflumuron-exposed females, respectively, successfully ingested blood). Triflumuron-surviving females ingested roughly 30% less blood and laid 25% fewer eggs than the control females. The treated males and females exhibited a diminished ability to copulate, resulting in less viable eggs. PMID:19274375

  16. A three-dimensionally chitin nanofiber/carbon nanotube hydrogel network for foldable conductive paper.

    Science.gov (United States)

    Chen, Chuchu; Yang, Chuang; Li, Suiyi; Li, Dagang

    2015-12-10

    We reported a highly conductive nanocomposite made with multiwalled carbon nanotubes (MWCNTs) and chitin nanofibers (ChNFs). The MWCNTs were dispersed into ChNFs by the simple process of vacuum-filtration, forming a three-dimensional network structure. In this approach, MWCNT acted as a filler to introduce electron channel paths throughout the ChNF skeleton. And then, a hybrid hydrogel system (20 wt.% NaOH, -18 °C) was applied to prepare the ChNF/MWCNT gel-film followed with drying process. It is found that the resultant ChNF/MWCNT gel-film exposed much more MWCNT areas forming denser structure due to the shrinking of ChNFs after the gelation treatment. Compared with ChNF/MWCNT film, the one treated under hydrogel system (ChNF/MWCNT gel-film) exhibited almost twice higher conductivity (9.3S/cm for 50 wt.% MWCNTs in gel-film; whereas 4.7S/cm for 50 wt.% MWCNTs in film). Moreover, the facile and low-cost of this conductive paper may have great potential in development of foldable electronic devices.

  17. A novel chitin binding crayfish molar tooth protein with elasticity properties.

    Directory of Open Access Journals (Sweden)

    Jenny Tynyakov

    Full Text Available The molar tooth of the crayfish Cherax quadricarinatus is part of the mandible, and is covered by a layer of apatite (calcium phosphate. This tooth sheds and is regenerated during each molting cycle together with the rest of the exoskeleton. We discovered that molar calcification occurs at the pre-molt stage, unlike calcification of the rest of the new exoskeleton. We further identified a novel molar protein from C. quadricarinatus and cloned its transcript from the molar-forming epithelium. We termed this protein Cq-M13. The temporal level of transcription of Cq-M13 in an NGS library of molar-forming epithelium at different molt stages coincides with the assembly and mineralization pattern of the molar tooth. The predicted protein was found to be related to the pro-resilin family of cuticular proteins. Functionally, in vivo silencing of the transcript caused molt cycle delay and a recombinant version of the protein was found to bind chitin and exhibited elastic properties.

  18. Chitin-Lignin Material as a Novel Matrix for Enzyme Immobilization

    Directory of Open Access Journals (Sweden)

    Jakub Zdarta

    2015-04-01

    Full Text Available Innovative materials were made via the combination of chitin and lignin, and the immobilization of lipase from Aspergillus niger. Analysis by techniques including FTIR, XPS and 13C CP MAS NMR confirmed the effective immobilization of the enzyme on the surface of the composite support. The electrokinetic properties of the resulting systems were also determined. Results obtained from elemental analysis and by the Bradford method enabled the determination of optimum parameters for the immobilization process. Based on the hydrolysis reaction of para-nitrophenyl palmitate, a determination was made of the catalytic activity, thermal and pH stability, and reusability. The systems with immobilized enzymes were found to have a hydrolytic activity of 5.72 mU, and increased thermal and pH stability compared with the native lipase. The products were also shown to retain approximately 80% of their initial catalytic activity, even after 20 reaction cycles. The immobilization process, using a cheap, non-toxic matrix of natural origin, leads to systems with potential applications in wastewater remediation processes and in biosensors.

  19. KARAKTERISASI KITIN DEASETILASE TERMOSTABIL ISOLAT BAKTERI ASAL PANCURAN TUJUH, BATURADEN, JAWA TENGAH [Characterization of Thermostable Chitin Deacetylase from Bacteria Strain Pancuran Tujuh, Baturaden, Center of Java

    Directory of Open Access Journals (Sweden)

    Deuxianto Hendarsyah3

    2006-04-01

    Full Text Available Chitin deacetylase is the enzymes that has important role in converting chitin to chitosan. In nature, chitin is the second most abundant natural biopolymer after cellulose. Generally, chitin easily obtained from outer shell of crustaceans, arthropods, and also detectable on cell wall of some type of fungal (Zygomycetes. The chitin deacetylase was isolated from Bacillus sp PT2-3. It was found that the highest specific activity was attained at pH 8 60°C. The addition of 5 mM Zn2+ and 5 mM Mn2+ increased the specific activity of the enzyme, 4.39% and 7.8%, respectively, and the increase was only 2.19% when the addition was 2 mM Mn2+. On the contrary the addition of Ca2+, Mg2+ and Fe2+ decrease the specific activity 46.83%, 41.22% and 47.32%, respectively. The enzyme activity was relatively stable at 60°C for 60 minutes, while lengthen the time to 90 minutes, decreased the activity 15.05 %, and the decrease was 26.13% at temperature of 70°C for 180 minutes.

  20. Fluorescence microscopical studies on chitin distribution in the cell wall of giant cells of Saccharomyces uvarum, grown following X-radiaiton treatment

    International Nuclear Information System (INIS)

    Teast cells are synchronized and modiated with X-rays (1.0 kGy) in the Cr, phase. Their growth behaviour is observed in suspension cultures and the formation of giant cells noted. The chitin structures are selectively stained with the fluorescent dye Calcofluor white. In the unradiated cells the chitin is deposited at the bud constriction site in the form of rings in the mother cell wall, whereas for irradiated cells only one chitin ring of normal appearance is formed between the mother cell and first bud equivalent. Between further bud equivalents an intensification of fluorescence is occasionally noted, however the organisation of the chitin into a regular ring arrangement is disturbed. In giant cells the facility for primary and secondary septa formation is missing and these are essential for successful cell division. By further experiments it was possible to identify the cause of disturbance in the cell cycle of irradiated cells. Giant cells only form one chitin ring because its DNA is replicated one time only. The major cause triggering the actual formation of giant cells must be considered the missing distribution of the once-rephicated DNA. All processes in the cell cycle dependent on this step are therefore stopped and only bud formation which occurs independently continues along its rhytmical path. (orig./MG)

  1. Effect of Corn Steep Liquor (CSL and Cassava Wastewater (CW on Chitin and Chitosan Production by Cunninghamella elegans and Their Physicochemical Characteristics and Cytotoxicity

    Directory of Open Access Journals (Sweden)

    Lúcia Raquel Ramos Berger

    2014-02-01

    Full Text Available Microbiological processes were used for chitin and chitosan production with Cunninghamella elegans UCP/WFCC 0542 grown in different concentrations of two agro-industrial wastes, corn steep liquor (CSL and cassava wastewater (CW established using a 22 full factorial design. The polysaccharides were extracted by alkali-acid treatment and characterized by infrared spectroscopy, viscosity, thermal analysis, elemental analysis, scanning electron microscopy and X-ray diffraction. The cytotoxicity of chitosan was evaluated for signs of vascular change on the chorioallantoic membrane of chicken eggs. The highest biomass (9.93 g/L was obtained in trial 3 (5% CW, 8% CSL, the greatest chitin and chitosan yields were 89.39 mg/g and 57.82 mg/g, respectively, and both were obtained in trial 2 (10% CW, 4% CSL. Chitin and chitosan showed a degree of deacetylation of 40.98% and 88.24%, and a crystalline index of 35.80% and 23.82%, respectively, and chitosan showed low molecular weight (LMW 5.2 × 103 Da. Chitin and chitosan can be considered non-irritating, due to the fact they do not promote vascular change. It was demonstrated that CSL and CW are effective renewable agroindustrial alternative substrates for the production of chitin and chitosan.

  2. The N-terminal cysteine-rich domain of tobacco class I chitinase is essential for chitin binding but not for catalytic or antifungal activity.

    Science.gov (United States)

    Iseli, B; Boller, T; Neuhaus, J M

    1993-09-01

    The vacuolar chitinases of class I possess an N-terminal cysteine-rich domain homologous to hevein and chitin-binding lectins such as wheat germ agglutinin and Urtica dioica lectin. To investigate the significance of this domain for the biochemical and functional characteristics of chitinase, chimeric genes encoding the basic chitinase A of tobacco (Nicotiana tabacum) with and without this domain were constructed and constitutively expressed in transgenic Nicotiana sylvestris. The chitinases were subsequently isolated and purified to homogeneity from the transgenic plants. Chromatography on colloidal chitin revealed that only the form with the N-terminal domain, and not the one without it, had chitin-binding properties, demonstrating directly that the domain is a chitin-binding domain (CBD). Under standard assay conditions with radioactive colloidal chitin, both forms of chitinase had approximately the same catalytic activity. However, kinetic analysis demonstrated that the enzyme without CBD had a considerably lower apparent affinity for its substrate. The pH and temperature optima of the two chitinases were similar, but the form with the CBD had an approximately 3-fold higher activation energy and retained a higher activity at low pH values. Both chitinases were capable of inhibiting growth of Trichoderma viride, although the form with the CBD was about three times more effective than the one without it. Thus, the CBD is not necessary for catalytic or antifungal activity of chitinase. PMID:8208848

  3. Bio-based epoxy/chitin nanofiber composites cured with amine-type hardeners containing chitosan.

    Science.gov (United States)

    Shibata, Mitsuhiro; Enjoji, Motohiro; Sakazume, Katsumi; Ifuku, Shinsuke

    2016-06-25

    Sorbitol polyglycidyl ether (SPE) which is a bio-based water-soluble epoxy resin was cured with chitosan (CS) and/or a commercial water-soluble polyamidoamine- or polyetheramine-type epoxy hardener (PAA or PEA). Furthermore, biocomposites of the CS-cured SPE (CS-SPE) and CS/PAA- or CS/PEA-cured SPE (SPE-CA or SPE-CE) biocomposites with chitin nanofiber (CNF) were prepared by casting and compression molding methods, respectively. The curing reaction of epoxy and amino groups of the reactants was confirmed by the FT-IR spectral analysis. SPE-CS and SPE-CA were almost transparent films, while SPE-CE was opaque. Transparency of SPE-CS/CNF and SPE-CA/CNF became a little worse with increasing CNF content. The tanδ peak temperature of SPE-CS was higher than those of SPE-PAA and SPE-PEA. SPE-CA or SPE-CE exhibited two tanδ peak temperatures related to glass transitions of the CS-rich and PAA-rich or PEA-rich moieties. The tanδ peak temperatures related to the CS-rich and PAA-rich moieties increased with increasing CNF content. A higher order of tensile strengths and moduli of the cured resins was SPE-CS≫SPE-CA>SPE-CE. The tensile strength and modulus of each sample were much improved by the addition of 3wt% CNF, while further addition of CNF caused a lowering of the strength and modulus. PMID:27083797

  4. Papain incorporated chitin dressings for wound debridement sterilized by gamma radiation

    International Nuclear Information System (INIS)

    Wound debridement is essential for the removal of necrotic or nonviable tissue from the wound surface to create an environment conducive to healing. Nonsurgical enzymatic debridement is an attractive method due to its effectiveness and ease of use. Papain is a proteolytic enzyme derived from the fruit of Carica papaya and is capable of breaking down a variety of necrotic tissue substrates. The present study was focused on the use of gamma radiation for sterilization of papain dressing with wound debriding activity. Membranes with papain were prepared using 0.5% chitin in lithium chloride/dimethylacetamide solvent and sterilized by gamma radiation. Fluid absorption capacity of chitin–papain membranes without glycerol was 14.30±6.57% in 6 h. Incorporation of glycerol resulted in significant (p2/24 h at 24 h. Gamma irradiation at 25 kGy was found suitable for sterilization of the dressings. Infrared (IR) spectral scanning has shown that papain was stable on gamma irradiation at 25–35 kGy. The irradiated chitin–papain membranes were impermeable to different bacterial strains and also exhibited strong bactericidal action against both Gram-positive and Gram-negative bacteria. The fluid handling characteristics and the antimicrobial properties of chitin–papain membranes sterilized by gamma radiation were found suitable for use as wound dressing with debriding activity. - Highlight: ► Use of gamma radiation for sterilization of papain wound dressing was studied. ► Fluid handling and antimicrobial properties of irradiated dressings was evaluated. ► Gamma irradiation at 25 kGy was found suitable for sterilization of the dressings.

  5. Research Development in Chitin Deacetylase(CDA)%几丁质脱乙酰酶(CDA)的研究进展

    Institute of Scientific and Technical Information of China (English)

    闵婷; 倪孟祥

    2011-01-01

    从多种真菌可分离纯化得到几丁质脱乙酰酶(CDA),CDA催化水解几丁质分子中的乙酰基生成壳聚糖,CDA与传统的浓碱热化学法生产壳聚糖相比,酶法催化提供了一种脱乙酰位点可控的、几丁质主链不被降解的和对环境友好的反应过程,从而得到优质的壳聚糖或壳寡糖.CDA具有重要的生物物理功能和广阔的潜在应用价值.该综述着重介绍了真菌CDA的研究进展,包括CDA的来源、CDA的生理生化性质、底物特异性、生物学功能和潜在应用价值.%Chitin deacetylases(CDA) have been found from several fungi. The enzyme catalyses the hydrolysis of N-acetamido groups of N-acetyl-D-glucosa mine in chitin, converting it to chitosan. The use of CDA for the conversion of chitin to chitosan, in contrast to the presently used chemical procedure, offers the possibility of a controlled, non-degradable and environmentally-friendly process, resulting in the production of novel, well-defined chitosan oligomers and polymers. CDA have important biophysiological functions and immense potential applications. In recent years, researches on fungal CDA have made a rapid progress. The present review will focus on the recent research developments of fungal CDA, including their source, biochemistry property, substrate specificity, biological function and potential application.

  6. Structure and interactions of calcite spherulites with {alpha}-chitin in the brown shrimp (Penaeus aztecus) shell

    Energy Technology Data Exchange (ETDEWEB)

    Heredia, A. [Instituto de Ciencias Nucleares, Departamento de Quimica de Radiaciones y Radioquimica, UNAM, Circuito Exterior C.U. Apdo., Postal 70-543, 04510 Mexico, D.F. (Mexico); Physikalisches Institut and Center for Nanotechnology, Universitaet Muenster, Gievenbecker Weg 11, 48149 Muenster (Germany); Aguilar-Franco, M. [Instituto de Fisica, Depto de Fisicoquimica, UNAM, Circuito Exterior s/n, Ciudad Universitaria Apartado Postal 20-364 01000 Mexico D.F. (Mexico); Magana, C. [Instituto de Fisica, Depto de Estado Solido, UNAM, Circuito Exterior s/n, Ciudad Universitaria Apartado Postal 20-364 01000 Mexico D.F. (Mexico); Flores, C. [Instituto de Investigaciones en Materiales, Depto de Estado Solido, Laboratorio de Biomateriales, UNAM, Circuito Exterior C.U. S/N CP 04510 Mexico, D.F. (Mexico); Pina, C. [Instituto de Investigaciones en Materiales, Depto de Estado Solido, Laboratorio de Biomateriales, UNAM, Circuito Exterior C.U. S/N CP 04510 Mexico, D.F. (Mexico); Velazquez, R. [Centro de Fisica Aplicada Tecnologia Avanzada, UNAM, Km. 15 Carretera Queretaro-San Luis Potosi, C.P. 76230, Queretaro, Qro. (Mexico); Schaeffer, T.E. [Physikalisches Institut and Center for Nanotechnology, Universitaet Muenster, Gievenbecker Weg 11, 48149 Muenster (Germany); Bucio, L. [Instituto de Fisica, Depto de Estado Solido, UNAM, Circuito Exterior s/n, Ciudad Universitaria Apartado Postal 20-364 01000 Mexico D.F. (Mexico); Basiuk, V.A. [Instituto de Ciencias Nucleares, Departamento de Quimica de Radiaciones y Radioquimica, UNAM, Circuito Exterior C.U. Apdo., Postal 70-543, 04510 Mexico, D.F. (Mexico)

    2007-01-15

    White spots form in the brown shrimp (Penaeus aztecus, Decapoda) shell during frozen storage. The mineral formed consists of calcite incorporated into an amorphous {alpha}-chitin matrix. We studied mechanisms of interaction of amorphous {alpha}-chitin macromolecules with hkl crystal planes to form highly ordered structures, as well as the role of specific sites in the biopolymer, which can be related to nucleation and spheroidal crystal growth. We used low vacuum scanning electron microscopy (LVSEM), X-ray powder diffraction (XRD), atomic force microscopy (AFM), Fourier-transform infrared spectroscopy (FT-IR), and molecular mechanics modeling (MM+ method). AFM images showed fingerprint distances in the biopolymer and a highly layered structure in the crystalline material. The presence of {alpha}-chitin, with a specific spatial distribution of radicals, is thought to be responsible for nucleation and to thermodynamically stabilize ions to form the spherulite crystalline phase, which are usually oval to spherical (0.10 to 200 {mu}m in diameter). Our models of crystal-biopolymer interaction found high affinity of CO{sub 3} {sup 2-} anions in the (104) crystalline plane (the main plane in calcite monocrystals) to NH- groups of the biopolymer, as well as of the C=O in the biopolymer to Ca{sup 2+} cations in the crystalline structure. These interactions explain the spherical growth and inhibition in some planes. The specific physicochemical interactions (docking of groups depending on their geometrical distribution) suggest that the biomineral structure is controlled by the biopolymer on a local scale. This information is useful for further design and improvement of (hybrid) materials for versatile application, from nanotechnology to biomedicine and engineering.

  7. Extensively deacetylated high molecular weight chitosan from the multistep ultrasound-assisted deacetylation of beta-chitin.

    Science.gov (United States)

    Fiamingo, Anderson; Delezuk, Jorge Augusto de Moura; Trombotto, Stéphane; David, Laurent; Campana-Filho, Sergio Paulo

    2016-09-01

    High intensity ultrasound irradiation was used to convert beta-chitin (BCHt) into chitosan (CHs). Typically, beta-chitin was suspended in 40% (w/w) aqueous sodium hydroxide at a ratio 1/10 (gmL(-1)) and then submitted to ultrasound-assisted deacetylation (USAD) during 50min at 60°C and a fixed irradiation surface intensity (52.6Wcm(-2)). Hydrogen nuclear magnetic resonance spectroscopy and capillary viscometry were used to determine the average degree of acetylation (DA‾) and viscosity average degree of polymerization (DPv‾), respectively, of the parent beta-chitin (DA‾=80.7%; DPv‾=6865) and USAD chitosans. A first USAD reaction resulted in chitosan CHs1 (DA‾=36.7%; DPv‾=5838). Chitosans CHs2 (DA‾=15.0%; DPv‾=5128) and CHs3 (DA‾=4.3%; DPv‾=4889) resulted after repeating the USAD procedure to CHs1 consecutively once and twice, respectively. Size-exclusion chromatography analyzes allowed the determination of the weight average molecular weight (Mw‾) and dispersity (Ð) of CHs1 (Mw‾=1,260,000gmol(-1); Ð=1.4), CHs2 (Mw‾=1,137,000gmol(-1); Ð=1.4) and CHs3 (Mw‾=912,000gmol(-1); Ð=1.3). Such results revealed that, thanks to the action of high intensity ultrasound irradiation, the USAD process allowed the preparation of unusually high molecular weight, randomly deacetylated chitosan, an important breakthrough to the development of new high grade chitosan-based materials displaying superior mechanical properties. PMID:27150748

  8. [Study on preparation of the pH sensitive hydroxyethyl chitin/poly (acrylic acid) hydrogel and its drug release property].

    Science.gov (United States)

    Zhao, Yu; Chen, Guohua; Sun, Mingkun; Jin, Zhitao; Gao, Congjie

    2006-04-01

    Hydroxyethyl chitin (HECH) is a water soluble chitin derivative made by etherification of chitin, ethylene chlorohydrin was used as etherification reagent in this reaction. A novel interpenetrating polymer network (IPN) composed of HECH/PAA was prepared. The IR spectra confirmed that HECH/PAA was formed through chemical bond interaction. The sensitivity of this hydrogel to temperature and pH was studied. The swelling ratio of this hydrogel in artificial intestinal juice is much greater than that in artificial gastric juice. The IPN hydrogel exhibited a typical pH-sensitivity, and its degree of swelling ratio increased with the increase of temperature. The sustained-release drug system of Dichlofenac potassium was prepared by using HECH/PAA as the drug carrier. The release experiment showed a perfect release behavior in artificial intestinal juice. This IPN is expected to be used as a good drug delivery system of enteric medicine. PMID:16706361

  9. Biocompatibility of potential wound management products: fungal mycelia as a source of chitin/chitosan and their effect on the proliferation of human F1000 fibroblasts in culture.

    Science.gov (United States)

    Chung, L Y; Schmidt, R J; Hamlyn, P F; Sagar, B F; Andrews, A M; Turner, T D

    1994-04-01

    Aspergillus oryzae, Mucor mucedo, and Phycomyces blakesleeanus cultures were examined as sources of chitin/chitosan. The nitrogen content of the alkali-treated mycelia/sporangiophores of A. oryzae, M. mucedo, and P. blakesleeanus was 2.52, 3.61, and 6.27% w/w, which relates to an estimated chitin content of 37, 52, and 91%, respectively. The effect of these fungal materials on the rate of proliferation of human F1000 fibroblasts in culture was examined. At 0.01% w/v, all three materials exhibited significant (P mucedo produced a significant (P mucedo, possessed cell attractant properties, again correlating with chitin content. If developed for use as wound management materials, the sporangiophores of P. blakesleeanus and the mycelium of M. mucedo could possibly promote the growth of fibroblasts and provide a matrix for their anchorage, thus contributing to the granulation phase of the healing cascade.

  10. Conversion of α-chitin substrates with varying particle size and crystallinity reveals substrate preferences of the chitinases and lytic polysaccharide monooxygenase of Serratia marcescens.

    Science.gov (United States)

    Nakagawa, Yuko S; Eijsink, Vincent G H; Totani, Kazuhide; Vaaje-Kolstad, Gustav

    2013-11-20

    Industrial depolymerization of chitinous biomass generally requires numerous steps and the use of deleterious substances. Enzymatic methods provide an alternative, but fundamental knowledge that could direct potential development of industrial enzyme cocktails is scarce. We have studied the contribution of monocomponent chitinases (ChiA, -B, and -C) and the lytic polysaccharide monooxygenase (LPMO) from Serratia marcescens on depolymerization of α-chitin substrates with varying particle size and crystallinity that were generated using a converge mill. For all chitinases activity was positively correlated to a decline in particle size and crystallinity. Especially ChiC, the only nonprocessive endochitinase from the S. marcescens chitinolytic machinery, benefited from mechanical pretreatment. Combining the chitinases revealed clear synergies for all substrates tested. CBP21, the chitin-active LPMO from S. marcescens, increased solubilization of substrates with high degrees of crystallinity when combined with each of the three chitinases, but this synergy was reduced upon decline in crystallinity.

  11. Vicilins (7S storage globulins of cowpea (Vigna unguiculata seeds bind to chitinous structures of the midgut of Callosobruchus maculatus (Coleoptera: Bruchidae larvae

    Directory of Open Access Journals (Sweden)

    Sales M.P.

    2001-01-01

    Full Text Available The presence of chitin in midgut structures of Callosobruchus maculatus larvae was shown by chemical and immunocytochemical methods. Detection by Western blotting of cowpea (Vigna unguiculata seed vicilins (7S storage proteins bound to these structures suggested that C. maculatus-susceptible vicilins presented less staining when compared to C. maculatus-resistant vicilins. Storage proteins present in the microvilli in the larval midgut of the bruchid were recognized by immunolabeling of vicilins in the appropriate sections with immunogold conjugates. These labeling sites coincided with the sites labeled by an anti-chitin antibody. These results, taken together with those previously published showing that the lower rates of hydrolysis of variant vicilins from C. maculatus-resistant seeds by the insect's midgut proteinases and those showing that vicilins bind to chitin matrices, may explain the detrimental effects of variant vicilins on the development of C. maculatus larvae.

  12. Induction of innate immunity by Apergillus fumigatus cell wall polysaccharides is enhanced by the composite presentation of chitin and beta-glucan

    DEFF Research Database (Denmark)

    Dubey, L. K.; Moeller, J. B.; Schlosser, A.;

    2014-01-01

    Chitin and beta-glucan are conserved throughout evolution in the fungal cell wall and are the most common polysaccharides in fungal species. Together, these two polysaccharides form a structural scaffold that is essential for the survival of the fungus. In the present study, we demonstrated...... that Aspergillus fumigatus alkali-insoluble cell wall fragments (AIF), composed of chitin linked covalently to beta-glucan, induced enhanced immune responses when compared with individual cell wall polysaccharides. Intranasal administration of AIF induced eosinophil and neutrophil recruitment, chitinase activity......, TNF-alpha and TSLP production in mice lungs. Selective destruction of chitin or beta-glucan from AIF significantly reduced eosinophil and neutrophil recruitment as well as chitinase activity and cytokine expression by macrophages, indicating the synergistic effect of the cell wall polysaccharides when...

  13. Single step synthesis of chitin/chitosan-based graphene oxide–ZnO hybrid composites for better electrical conductivity and optical properties

    International Nuclear Information System (INIS)

    Highlights: ► UV absorption at 260–360 nm confirmed strong binding of ZnO with chitosan–GO sheets. ► Chitin-based GO–ZnO shows higher electrical conductivity than chitosan-based GO–ZnO. ► Chitin-based GO–ZnO will useful in sensing, catalysis and energy storage applications. -- Abstract: We synthesized two composites/hybrid composites with a graphene oxide (GO)/mixed GO–ZnO filler using either a chitin or a chitosan matrix. Fourier transform infrared spectroscopy analysis confirmed that chitin had been converted to chitosan during matrix fabrication because only chitosan, ZnO and GO were shown to be present in the composites/hybrid composites. Raman spectroscopy indicated the display of D and G bands at 1345 cm−1 and 1584 cm−1, respectively. UV absorption peaks appeared at 260–360 nm and 201 nm in both hybrid composites, which indicate a strong binding of ZnO within the chitosan–GO sheets. High resolution scanning electron microscopy and atomic force microscopy studies demonstrated that on a molecular scale ZnO was well dispersed in the hybrid composites. Impedance spectroscopy and a four-probe resistivity method were used for room temperature electrical conductivity measurements. The electrical conductivity of the chitin-based GO–ZnO hybrid composites was estimated to be ∼5.94 × 106 S/cm and was greater than that of the chitosan-based GO–ZnO hybrid composite (∼4.13 × 106 S/cm). The chitin-based GO–ZnO hybrid composite had a higher optical band gap (3.4 eV) than the chitosan-based GO–ZnO hybrid composite (3.0 eV). The current–voltage measurement showed that electrical sheets resistance of the chitosan-based composites decreased with formation of ZnO

  14. Chondroitin sulfate, hyaluronic acid and chitin/chitosan production using marine waste sources: characteristics, applications and eco-friendly processes: a review.

    Science.gov (United States)

    Vázquez, José Antonio; Rodríguez-Amado, Isabel; Montemayor, María Ignacia; Fraguas, Javier; González, María Del Pilar; Murado, Miguel Anxo

    2013-03-01

    In the last decade, an increasing number of glycosaminoglycans (GAGs), chitin and chitosan applications have been reported. Their commercial demands have been extended to different markets, such as cosmetics, medicine, biotechnology, food and textiles. Marine wastes from fisheries and aquaculture are susceptible sources for polymers but optimized processes for their recovery and production must be developed to satisfy such necessities. In the present work, we have reviewed different alternatives reported in the literature to produce and purify chondroitin sulfate (CS), hyaluronic acid (HA) and chitin/chitosan (CH/CHs) with the aim of proposing environmentally friendly processes by combination of various microbial, chemical, enzymatic and membranes strategies and technologies.

  15. Characterization of a novel Salmonella typhimurium chitinase which hydrolyzes chitin, chitooligosaccharides and an N-acetyllactosamine conjugate

    DEFF Research Database (Denmark)

    Larsen, Tanja; Petersen, Bent O.; Storgaard, Birgit Groth;

    2011-01-01

    Salmonella contain genes annotated as chitinases; however, their chitinolytic activities have never been verified. We now demonstrate such an activity for a chitinase assigned to glycoside hydrolase family 18 encoded by the SL0018 (chiA) gene in Salmonella enterica Typhimurium SL1344. A C...... carboxymethyl chitin Remazol Brilliant Violet but does not act on 4-nitrophenyl N-acetyl-ß-D-glucosaminide, peptidoglycan or 4-nitrophenyl ß-D-cellobioside. Enzyme activity was also characterized by directly monitoring product formation using (1)H-nuclear magnetic resonance which showed that chitin is a...

  16. CONDUCTIVITY METHOD APPLIED TO THE STUDY OF INTERACTION BETWEEN ADSORBENT AND ADSORBATE I.ADSORPTION OF LOW CONCENYRATION OF FREE ACID BY REGENERABLE CHITIN

    Institute of Scientific and Technical Information of China (English)

    ChenBingren; HeGuangping; 等

    1997-01-01

    The adsorption of low concentration of free acid by regenerable chitin is followed by electric conductance determination.The effect of acid concentratioin,content of functioinal amino groups,and ionic strength on adsorption was discussed.Experimental results indicate that the active centre of regenerable chitin is the free amino groups on ist surface ,and that the rate of adsorption of free acid was found to be affected by two factors:the interaction between the adsorbent and the adsorbate in solution and that between the adsorbate molecules or ions in solution.

  17. Increased chitin biosynthesis contributes to the resistance of Penicillium polonicum against the antifungal protein PgAFP.

    Science.gov (United States)

    Delgado, Josué; Owens, Rebecca A; Doyle, Sean; Asensio, Miguel A; Núñez, Félix

    2016-01-01

    Antifungal proteins from molds have been proposed as a valuable tool against unwanted molds, but the resistance of some fungi limits their use. Resistance to antimicrobial peptides has been suggested to be due to lack of interaction with the mold or to a successful response. The antifungal protein PgAFP produced by Penicillium chrysogenum inhibits the growth of various ascomycetes, but not Penicillium polonicum. To study the basis for resistance to this antifungal protein, localization of PgAFP and metabolic, structural, and morphological changes were investigated in P. polonicum. PgAFP bound the outer layer of P. polonicum but not regenerated chitin, suggesting an interaction with specific molecules. Comparative two-dimensional gel electrophoresis (2D-PAGE) and comparative quantitative proteomics revealed changes in the relative abundance of several proteins from ribosome, spliceosome, metabolic, and biosynthesis of secondary metabolite pathways. The proteome changes and an altered permeability reveal an active reaction of P. polonicum to PgAFP. The successful response of the resistant mold seems to be based on the higher abundance of protein Rho GTPase Rho1 that would lead to the increased chitin deposition via cell wall integrity (CWI) signaling pathway. Thus, combined treatment with chitinases could provide a complementary means to combat resistance to antifungal proteins.

  18. 'Strengthening the fungal cell wall through chitin-glucan cross-links: effects on morphogenesis and cell integrity'.

    Science.gov (United States)

    Arroyo, Javier; Farkaš, Vladimír; Sanz, Ana Belén; Cabib, Enrico

    2016-09-01

    The cross-linking of polysaccharides to assemble new cell wall in fungi requires transglycosylation mechanisms by which preexisting glycosidic linkages are broken and new linkages are created between the polysaccharides. The molecular mechanisms for these processes, which are essential for fungal cell biology, are only now beginning to be elucidated. Recent development of in vivo and in vitro biochemical approaches has allowed characterization of important aspects about the formation of chitin-glucan covalent cell wall cross-links by cell wall transglycosylases of the CRH family and their biological function. Covalent linkages between chitin and glucan mediated by Crh proteins control morphogenesis and also play important roles in the remodeling of the fungal cell wall as part of the compensatory responses necessary to counterbalance cell wall stress. These enzymes are encoded by multigene families of redundant proteins very well conserved in fungal genomes but absent in mammalian cells. Understanding the molecular basis of fungal adaptation to cell wall stress through these and other cell wall remodeling enzymatic activities offers an opportunity to explore novel antifungal treatments and to identify potential fungal virulence factors. PMID:27185288

  19. AN INTEGRATIVE WAY OF TEACHING MOLECULAR CELL BIOLOGY AND PROTEIN CHEMISTRY USING ACTIN IMMOBILIZATION ON CHITIN FOR PURIFYING MYOSIN II.

    Directory of Open Access Journals (Sweden)

    M.G. Souza

    2007-05-01

    Full Text Available Our intent is to present our experience on teaching Molecular Cell Biology andProtein Chemistry at UNIRIO through an innovative approach that includes myosin IIextraction and purification. We took advantage of the properties of muscle contractionand propose a simple method for purifying myosin II by affinity chromatography. Thisoriginal method is based on the preparation of an affinity column containing actinmolecules covalently bound to chitin particles. We propose a three-week syllabus thatincludes lectures and bench experimental work. The syllabus favors the activelearning of protein extraction and purification, as well as, of scientific concepts suchas muscle contraction, cytoskeleton structure and its importance for the living cell. Italso promotes the learning of the biotechnological applications of chitin and theapplications of protein immobilization in different industrial fields. Furthermore, theactivities also target the development of laboratorial technical abilities, thedevelopment of problem solving skills and the ability to write up a scientific reportfollowing the model of a scientific article. It is very important to mention that thissyllabus can be used even in places where a facility such as ultra-centrifugation islacking.

  20. A Preliminary Evaluation of Lyophilized Gelatin Sponges, Enhanced with Platelet-Rich Plasma, Hydroxyapatite and Chitin Whiskers for Bone Regeneration

    Directory of Open Access Journals (Sweden)

    Andrew J. Spence

    2013-04-01

    Full Text Available The purpose of this study was to perform a number of preliminary in vitro evaluations on an array of modified gelatin gel sponge scaffolds for use in a bone graft application. The gelatin gels were modified through the addition of a number of components which each possess unique properties conducive to the creation and regeneration of bone: a preparation rich in growth factors (PRGF, a bioactive, lyophilized form of platelet-rich plasma, hydroxyapatite, and chitin whiskers. Platelet-rich plasma therapy is an emerging practice that has proven effective in a number of clinical applications, including enhancing bone repair through improved deposition of new bony matrix and angiogenesis. As such, the inclusion of PRGF in our gelatin scaffolds was intended to significantly enhance scaffold bioactivity, while the addition of hydroxyapatite and chitin whiskers were anticipated to increase scaffold strength. Additionally, the gelatin sponges, which readily dissolve in aqueous solutions, were subjected to 1-Ethyl-3-[3-dimethylaminopropyl]carbodiimide hydrochloride (EDC cross-linking, either during or post-gelation, to control their rate of degradation. Scaffolds were evaluated in vitro with respect to compressive strength, mass loss/degradation, protein release, and cellular interaction, with results demonstrating the potential of the gelatin gel sponge scaffold for use in the regeneration of bone.

  1. Influence of Functionalization Degree on the Rheological Properties of Isocyanate-Functionalized Chitin- and Chitosan-Based Chemical Oleogels for Lubricant Applications

    Directory of Open Access Journals (Sweden)

    Rocío Gallego

    2014-07-01

    Full Text Available This work deals with the influence of functionalization degree on the thermogravimetric and rheological behaviour of NCO-functionalized chitosan- and chitin-based oleogels. Chitosan and chitin were functionalized using different proportions of 1,6-hexamethylene diisocyanate (HMDI and subsequently dispersed in castor oil to promote the chemical reaction between the –NCO group of the modified biopolymer and the –OH group located in the ricinoleic fatty acid chain of castor oil, thus resulting in different oleogels with specific thermogravimetric and rheological characteristics. Biopolymers and oleogels were characterized through Fourier transform infrared spectroscopy (FTIR and thermogravimetric analysis (TGA. Small-amplitude oscillatory shear (SAOS measurements were performed on the oleogels. Oleogels presented suitable thermal resistance, despite the fact that the inclusion of HMDI moieties in the polymer structure led to a reduction in the onset temperature of thermal degradation. The insertion of low amounts of HMDI in both chitin and chitosan produces a drastic reduction in the values of oleogel viscoelastic functions but, above a critical threshold, they increase with the functionalization degree so that isocyanate functionalization results in a chemical tool to modulate oleogel rheological response. Several NCO-functionalized chitosan- and chitin-based oleogel formulations present suitable thermal resistance and rheological characteristics to be proposed as bio-based alternatives to traditional lubricating greases.

  2. A novel salt-tolerant chitobiosidase discovered by genetic screening of a metagenomic library derived from chitin-amended agricultural soil

    NARCIS (Netherlands)

    Cretoiu, Mariana Silvia; Berini, Francesca; Kielak, Anna Maria; Marinelli, Flavia; van Elsas, Jan Dirk

    2015-01-01

    Here, we report on the construction of a metagenomic library from a chitin-amended disease-suppressive agricultural soil and its screening for genes that encode novel chitinolytic enzymes. The library, constructed in fosmids in an Escherichia coli host, comprised 145,000 clones containing inserts of

  3. A High Diversity in Chitinolytic and Chitosanolytic Species and Enzymes and Their Oligomeric Products Exist in Soil with a History of Chitin and Chitosan Exposure

    Directory of Open Access Journals (Sweden)

    Malathi Nampally

    2015-01-01

    Full Text Available Chitin is one of the most abundant biomolecules on earth, and its partially de-N-acetylated counterpart, chitosan, is one of the most promising biotechnological resources due to its diversity in structure and function. Recently, chitin and chitosan modifying enzymes (CCMEs have gained increasing interest as tools to engineer chitosans with specific functions and reliable performance in biotechnological and biomedical applications. In a search for novel CCME, we isolated chitinolytic and chitosanolytic microorganisms from soils with more than ten-years history of chitin and chitosan exposure and screened them for chitinase and chitosanase isoenzymes as well as for their patterns of oligomeric products by incubating their secretomes with chitosan polymers. Of the 60 bacterial strains isolated, only eight were chitinolytic and/or chitosanolytic, while 20 out of 25 fungal isolates were chitinolytic and/or chitosanolytic. The bacterial isolates produced rather similar patterns of chitinolytic and chitosanolytic enzymes, while the fungal isolates produced a much broader range of different isoenzymes. Furthermore, diverse mixtures of oligosaccharides were formed when chitosan polymers were incubated with the secretomes of select fungal species. Our study indicates that soils with a history of chitin and chitosan exposure are a good source of novel CCME for chitosan bioengineering.

  4. Dietary Bacillus subtilis FPTB13 and chitin, single or combined, modulate systemic and cutaneous mucosal immunity and resistance of catla, Catla catla (Hamilton) against edwardsiellosis.

    Science.gov (United States)

    Sangma, Timothy; Kamilya, Dibyendu

    2015-12-01

    Effects of dietary administration of Bacillus subtilis FPTB13 and chitin, single or combined, on the systemic immunity, mucosal immunity and resistance of catla (Catla catla) against Edwardsiella tarda infection were investigated. The probiotic attributes of B. subtilis was tested by conducting antagonism study, safety in catla, in vitro immunomodulation and dietary immunomodulation. Results of these studies indicated the probiotic potential of the strain. From the preliminary dietary immunomodulation study, a dose of 10(9) B. subtilis cells g(-1) was selected for inclusion into diets for subsequent experiments. Experimental diets were prepared by adding B. subtilis (10(9) cells g(-1)), chitin (2%) and their combination to the basal diet. Different systemic and mucosal immunological parameters viz. oxygen radical production, myeloperoxidase content, lysozyme activity, total protein content and alkaline phosphatase activity showed significant enhancement (pdiet. B. subtilis and chitin alone also significantly elevated most of the immune responses. All the diets significantly increased the resistance of catla against E. tarda challenge. The highest post-challenge survival was observed in combined group (i.e. 63.33%). In conclusion, B. subtilis and chitin, alone or combined, had a health ameliorating effect in catla. The results also collectively suggest the usefulness of applying a combined probiotic and immunostimulant supplemented diet to achieve greater benefits. PMID:26616655

  5. Exposure to Diflubenzuron Results in an Up-Regulation of a Chitin Synthase 1 Gene in Citrus Red Mite, Panonychus citri (Acari: Tetranychidae

    Directory of Open Access Journals (Sweden)

    Wen-Kai Xia

    2014-02-01

    Full Text Available Chitin synthase synthesizes chitin, which is critical for the arthropod exoskeleton. In this study, we cloned the cDNA sequences of a chitin synthase 1 gene, PcCHS1, in the citrus red mite, Panonychus citri (McGregor, which is one of the most economically important pests of citrus worldwide. The full-length cDNA of PcCHS1 contains an open reading frame of 4605 bp of nucleotides, which encodes a protein of 1535 amino acid residues with a predicted molecular mass of 175.0 kDa. A phylogenetic analysis showed that PcCHS1 was most closely related to CHS1 from Tetranychus urticae. During P. citri development, PcCHS1 was constantly expressed in all stages but highly expressed in the egg stage (114.8-fold higher than in the adult. When larvae were exposed to diflubenzuron (DFB for 6 h, the mite had a significantly high mortality rate, and the mRNA expression levels of PcCHS1 were significantly enhanced. These results indicate a promising use of DFB to control P. citri, by possibly acting as an inhibitor in chitin synthesis as indicated by the up-regulation of PcCHS1 after exposure to DFB.

  6. Exposure to diflubenzuron results in an up-regulation of a chitin synthase 1 gene in citrus red mite, Panonychus citri (Acari: Tetranychidae).

    Science.gov (United States)

    Xia, Wen-Kai; Ding, Tian-Bo; Niu, Jin-Zhi; Liao, Chong-Yu; Zhong, Rui; Yang, Wen-Jia; Liu, Bin; Dou, Wei; Wang, Jin-Jun

    2014-01-01

    Chitin synthase synthesizes chitin, which is critical for the arthropod exoskeleton. In this study, we cloned the cDNA sequences of a chitin synthase 1 gene, PcCHS1, in the citrus red mite, Panonychus citri (McGregor), which is one of the most economically important pests of citrus worldwide. The full-length cDNA of PcCHS1 contains an open reading frame of 4605 bp of nucleotides, which encodes a protein of 1535 amino acid residues with a predicted molecular mass of 175.0 kDa. A phylogenetic analysis showed that PcCHS1 was most closely related to CHS1 from Tetranychus urticae. During P. citri development, PcCHS1 was constantly expressed in all stages but highly expressed in the egg stage (114.8-fold higher than in the adult). When larvae were exposed to diflubenzuron (DFB) for 6 h, the mite had a significantly high mortality rate, and the mRNA expression levels of PcCHS1 were significantly enhanced. These results indicate a promising use of DFB to control P. citri, by possibly acting as an inhibitor in chitin synthesis as indicated by the up-regulation of PcCHS1 after exposure to DFB. PMID:24590130

  7. Actin Immobilization on Chitin for Purifying Myosin II: A Laboratory Exercise That Integrates Concepts of Molecular Cell Biology and Protein Chemistry

    Science.gov (United States)

    de Souza, Marcelle Gomes; Grossi, Andre Luiz; Pereira, Elisangela Lima Bastos; da Cruz, Carolina Oliveira; Mendes, Fernanda Machado; Cameron, Luiz Claudio; Paiva, Carmen Lucia Antao

    2008-01-01

    This article presents our experience on teaching biochemical sciences through an innovative approach that integrates concepts of molecular cell biology and protein chemistry. This original laboratory exercise is based on the preparation of an affinity chromatography column containing F-actin molecules immobilized on chitin particles for purifying…

  8. Identification of Genes Putatively Involved in Chitin Metabolism and Insecticide Detoxification in the Rice Leaf Folder (Cnaphalocrocis medinalis Larvae through Transcriptomic Analysis

    Directory of Open Access Journals (Sweden)

    Hai-Zhong Yu

    2015-09-01

    Full Text Available The rice leaf roller (Cnaphalocrocis medinalis is one of the most destructive agricultural pests. Due to its migratory behavior, it is difficult to control worldwide. To date, little is known about major genes of C. medinalis involved in chitin metabolism and insecticide detoxification. In order to obtain a comprehensive genome dataset of C. medinalis, we conducted de novo transcriptome sequencing which focused on the major feeding stage of fourth-instar larvae, and our work revealed useful information on chitin metabolism and insecticide detoxification and target genes of C. medinalis. We acquired 29,367,797 Illumina reads and assembled these reads into 63,174 unigenes with an average length of 753 bp. Among these unigenes, 31,810 were annotated against the National Center for Biotechnology Information non-redundant (NCBI nr protein database, resulting in 24,246, 8669 and 18,176 assigned to Swiss-Prot, clusters of orthologous group (COG, and gene ontology (GO, respectively. We were able to map 10,043 unigenes into 285 pathways using the Kyoto Encyclopedia of Genes and Genomes Pathway database (KEGG. Specifically, 16 genes, including five chitin deacetylases, two chitin synthases, five chitinases and four other related enzymes, were identified to be putatively involved in chitin biosynthesis and degradation, whereas 360 genes, including cytochrome P450s, glutathione S-transferases, esterases, and acetylcholinesterases, were found to be potentially involved in insecticide detoxification or as insecticide targets. The reliability of the transcriptome data was determined by reverse transcription quantitative PCR (RT-qPCR for the selected genes. Our data serves as a new and valuable sequence resource for genomic studies on C. medinalis. The findings should improve our understanding of C. medinalis genetics and contribute to management of this important agricultural pest.

  9. Identification of Genes Putatively Involved in Chitin Metabolism and Insecticide Detoxification in the Rice Leaf Folder (Cnaphalocrocis medinalis) Larvae through Transcriptomic Analysis

    Science.gov (United States)

    Yu, Hai-Zhong; Wen, De-Fu; Wang, Wan-Lin; Geng, Lei; Zhang, Yan; Xu, Jia-Ping

    2015-01-01

    The rice leaf roller (Cnaphalocrocis medinalis) is one of the most destructive agricultural pests. Due to its migratory behavior, it is difficult to control worldwide. To date, little is known about major genes of C. medinalis involved in chitin metabolism and insecticide detoxification. In order to obtain a comprehensive genome dataset of C. medinalis, we conducted de novo transcriptome sequencing which focused on the major feeding stage of fourth-instar larvae, and our work revealed useful information on chitin metabolism and insecticide detoxification and target genes of C. medinalis. We acquired 29,367,797 Illumina reads and assembled these reads into 63,174 unigenes with an average length of 753 bp. Among these unigenes, 31,810 were annotated against the National Center for Biotechnology Information non-redundant (NCBI nr) protein database, resulting in 24,246, 8669 and 18,176 assigned to Swiss-Prot, clusters of orthologous group (COG), and gene ontology (GO), respectively. We were able to map 10,043 unigenes into 285 pathways using the Kyoto Encyclopedia of Genes and Genomes Pathway database (KEGG). Specifically, 16 genes, including five chitin deacetylases, two chitin synthases, five chitinases and four other related enzymes, were identified to be putatively involved in chitin biosynthesis and degradation, whereas 360 genes, including cytochrome P450s, glutathione S-transferases, esterases, and acetylcholinesterases, were found to be potentially involved in insecticide detoxification or as insecticide targets. The reliability of the transcriptome data was determined by reverse transcription quantitative PCR (RT-qPCR) for the selected genes. Our data serves as a new and valuable sequence resource for genomic studies on C. medinalis. The findings should improve our understanding of C. medinalis genetics and contribute to management of this important agricultural pest. PMID:26378520

  10. Preparation of High Purity, High Molecular-Weight Chitin from Ionic Liquids for Use as an Adsorbate for the Extraction of Uranium from Seawater

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, Robin [Univ. of Alabama, Tuscaloosa, AL (United States)

    2013-12-21

    Ensuring a domestic supply of uranium is a key issue facing the wider implementation of nuclear power. Uranium is mostly mined in Kazakhstan, Australia, and Canada, and there are few high-grade uranium reserves left worldwide. Therefore, one of the most appealing potential sources of uranium is the vast quantity dissolved in the oceans (estimated to be 4.4 billion tons worldwide). There have been research efforts centered on finding a means to extract uranium from seawater for decades, but so far none have resulted in an economically viable product, due in part to the fact that the materials that have been successfully demonstrated to date are too costly (in terms of money and energy) to produce on the necessary scale. Ionic Liquids (salts which melt below 100{degrees}C) can completely dissolve raw crustacean shells, leading to recovery of a high purity, high molecular weight chitin powder and to fibers and films which can be spun directly from the extract solution suggesting that continuous processing might be feasible. The work proposed here will utilize the unprecedented control this makes possible over the chitin fiber a) to prepare electrospun nanofibers of very high surface area and in specific architectures, b) to modify the fiber surfaces chemically with selective extractant capacity, and c) to demonstrate their utility in the direct extraction and recovery of uranium from seawater. This approach will 1) provide direct extraction of chitin from shellfish waste thus saving energy over the current industrial process for obtaining chitin; 2) allow continuous processing of nanofibers for very high surface area fibers in an economical operation; 3) provide a unique high molecular weight chitin not available from the current industrial process, leading to stronger, more durable fibers; and 4) allow easy chemical modification of the large surface areas of the fibers for appending uranyl selective functionality providing selectivity and ease of stripping. The

  11. Adsorption of Heavy Metal Ions by Adsorbent from Waste Mycelium Chitin%菌丝体-甲壳素水处理剂对重金属离子吸附性能的研究

    Institute of Scientific and Technical Information of China (English)

    苏海佳; 王丽娟; 谭天伟

    2002-01-01

    The adsorption properties of chitin adsorbent from mycelium of fermentation industries for the removal of heavy metal ions werestudied. The result shows that the chitin adsorbent has high adsorption capacity for many heavy metal ions and Ni2+ in citric acid. The influenceof pH was significant: When pH is higher than 4.0, the high adsorption capacity is obtained, otherwise H+ ion inhibits the adsorption of heavymetal ions. The comparison of the chitin adsorbent with some other commercial adsorbents was made, in which that the adsorption behavior ofchitin adsorbent is close to that of commercial cation exchange adsorbents, and its cost is much lower than those commercial adsorbents.

  12. Transcriptional regulation of the genes encoding chitin and β-1,3-glucan synthases from Ustilago maydis.

    Science.gov (United States)

    Robledo-Briones, Mariana; Ruiz-Herrera, José

    2012-07-01

    Transcriptional regulation of genes encoding chitin synthases (CHS) and β-1,3-glucan synthase (GLS) from Ustilago maydis was studied. Transcript levels were measured during the growth curve of yeast and mycelial forms, in response to ionic and osmotic stress, and during infection of maize plants. Expression of the single GLS gene was constitutive. In contrast, CHS genes expression showed differences depending on environmental conditions. Transcript levels were slightly higher in the mycelial forms, the highest levels occurring at the log phase. Ionic and osmotic stress induced alterations in the expression of CHS genes, but not following a defined pattern, some genes were induced and others repressed by the tested compounds. Changes in transcripts were more apparent during the pathogenic process. At early infection stages, only CHS6 gene showed significant transcript levels, whereas at the period of tumor formation CHS7 and CHS8 genes were also were induced.

  13. Activities of the Deriviatives of Chitin on the Osbeoblast Proliferation and the Effect on Bone Strength in Ovariectomized Rats

    Institute of Scientific and Technical Information of China (English)

    WEI Changzheng; LIU Wanshun; HAN Baoqin; DUAN Yixiang

    2006-01-01

    This study intends to examine the effects of different concentrations of four kinds of degradations of chitin:glucosamine (GLC), N-acetyl-D-glucosamine (NAG), chitooligosaccharide(COS), CM-chitooligosaccharide (CM-COS)-on the proliferation of MC3T3-E1 cell line cultured in vitro.Results suggest that all of the glucoses mentioned above promoted the proliferation of osteoblast, and various concentrations have different effects: the proliferation was remarkable 100 , 100 , 500 , 500 μg/mL ,respectively. Furthermore we choose the glucosamine as the material and study the effect on the bone strength in ovariectomized rats. The results showed that the middle does of glucosamine can significantly increase the bone strength of femur in ovariectomized rats.

  14. Cloning and identification of chitin binding proteins of tubeworm,Ridgeia piscesae, from hydrothermal vent%热液区管状蠕虫几丁质结合蛋白的克隆表达及功能鉴定

    Institute of Scientific and Technical Information of China (English)

    闫鑫富; 阮灵伟

    2012-01-01

    Hydrothermal vent tube worm is the one of the most typical hydrothermal species. In previous study,we constructed cDNA library of tube worm(Ridgeia piscesae) and sequencing result showed that it contains 23 chitin-binding proteins( CBPs). With high transcription level and diversity,each protein contains 1 ~3 different types of chitin binding domain ( s). In view of the important role in chitin degradation and the special habitats of the tube worms , we further studied the functional characterization of 4 typical chitin-binding proteins. After analyzed, the sequences of signal peptides were cut off and the fragments encoding chitin-binding proteins were amplified by PCR, inserted into pIZ-FLAG Vector and successfully expressed in Hi5 cells. In the chitin affinity assay,the results demonstrated that four FLAG-CBPs can bind to a-chitin respectively. Meanwhile, the supernatant of cell lysate including the expressed product FLAG-CBPs was able to enhance the activity of chitinase in the process of degrading a-chitin and β-chitin respectively. All the results suggest that four CBPs may act as a-chitin binding proteins and may enhance the activity of chitinase. In-depth study will be taken to verify other biological functions of chitin binding proteins and optimize their ability of catalyzation.%本文应用PCR技术对四种管状蠕虫几丁质结合蛋白进行了扩增,进而连接到pIZ-FLAG构建了重组表达载体,并在昆虫细胞中实现了几丁质结合蛋白的异源重组表达.我们对几丁质结合蛋白的功能进行了初步研究,亲和活性实验结果表明这四种几丁质结合蛋白对α-chitin具有亲和活性,并且可以辅助几丁质酶,对降解α-chitin和β-chitin均有不同程度的促进作用,且作用效果明显.结果表明,这四种几丁质结合蛋白均为α型,且可以促进几丁质酶的活性,对降解几丁质多糖具有巨大的应用潜力和应用价值.

  15. Binding of the AVR4 elicitor of Cladosporium fulvum to chitotriose units is facilitated by positive allosteric protein-protein interactions - The chitin-binding site of AVR4 represents a novel binding site on the folding scaffold shared between the invertebrate and the plant chitin-binding domain

    NARCIS (Netherlands)

    Burg, H.A. van den; Spronk, C.A.E.M.; Boeren, S.; Kennedy, M.A.; Vissers, J.P.C.; Vuister, G.W.; Wit, P. de; Vervoort, J.

    2004-01-01

    The attack of fungal cell walls by plant chitinases is an important plant defense response to fungal infection. Anti-fungal activity of plant chitinases is largely restricted to chitinases that contain a noncatalytic, plant-specific chitin-binding domain (ChBD) ( also called Hevein domain). Current

  16. Biodegradable chitin conduit tubulation combined with bone marrow mesenchymal stem cell transplantation for treatment of spinal cord injury by reducing glial scar and cavity formation

    OpenAIRE

    Feng Xue; Er-jun Wu; Pei-xun Zhang; Li-ya A; Yu-hui Kou; Xiao-feng Yin; Na Han

    2015-01-01

    We examined the restorative effect of modified biodegradable chitin conduits in combination with bone marrow mesenchymal stem cell transplantation after right spinal cord hemisection injury. Immunohistochemical staining revealed that biological conduit sleeve bridging reduced glial scar formation and spinal muscular atrophy after spinal cord hemisection. Bone marrow mesenchymal stem cells survived and proliferated after transplantation in vivo, and differentiated into cells double-positive fo...

  17. Core structure of aligned chitin fibers within the interlamellar framework extracted from Haliotis rufescens nacre. Part I: Implications for growth and mechanical response

    Directory of Open Access Journals (Sweden)

    Lubarda Vlado A.

    2012-01-01

    Full Text Available By means of consecutive alkaline and proteolytic treatments of the organic framework’s interlamellar layers extracted from the nacre of H. rufescens, we have exposed a core of aligned parallel chitin fibers. Our findings both verify basic elements of the interlamellar layer structural model of Levi-Kalisman et al. (2001 and extend the more detailed model of Bezares et al. (2008, 2010. We observe via SEM imaging of square millimeter sized samples, which include numerous interlamellar layers and micron sized, yet nanocrystalline, CaCO3 tiles whose native orientation within the shell was first documented, that the chitin fibers in all layers are aligned normal to the growth direction of the shell. Similar alignment has been suggested in the literature for two other classes of mollusks, viz. N. rupertus and P. martensii (Weiner and Traub, 1983; Wada, 1958, suggesting that this may be a more general motif. We find that in order to expose the chitin core it is necessary to first remove protein by an alkaline treatment followed by enzymatic digestion with proteinase-K. We also observe what appear to be the points of traversal of the exposed chitin core by mineral bridges. The implications of these findings touch directly and most specifically upon the expected mechanical properties of organic framework layers such as stiffness and relaxation time constants, viz. they should be planeorthotropic. Single interlamellar layers extracted from nacre should, by implication, also exhibit an orthotropic stiffness. These novel findings provide the structural picture required for a complete anisotropic, time dependent, constitutive description of nacre long thought to be a paradigm of structural optimization. Such a model is briefly described herein and is developed, in full, in Part II of this series.

  18. Identification of Genes Putatively Involved in Chitin Metabolism and Insecticide Detoxification in the Rice Leaf Folder (Cnaphalocrocis medinalis) Larvae through Transcriptomic Analysis

    OpenAIRE

    Hai-Zhong Yu; De-Fu Wen; Wan-Lin Wang; Lei Geng; Yan Zhang; Jia-Ping Xu

    2015-01-01

    The rice leaf roller (Cnaphalocrocis medinalis) is one of the most destructive agricultural pests. Due to its migratory behavior, it is difficult to control worldwide. To date, little is known about major genes of C. medinalis involved in chitin metabolism and insecticide detoxification. In order to obtain a comprehensive genome dataset of C. medinalis, we conducted de novo transcriptome sequencing which focused on the major feeding stage of fourth-instar larvae, and our work revealed usef...

  19. Cloning and Tissue-Specific Expression of a Chitin Deacetylase Gene from Helicoverpa armigera (Lepidoptera: Noctuidae) and Its Response to Bacillus thuringiensis.

    Science.gov (United States)

    Han, Guoying; Li, Xiumin; Zhang, Ting; Zhu, Xiaoting; Li, Jigang

    2015-01-01

    Chitin deacetylases (CDAs) convert chitin into chitosan, the N-deacetylated form of chitin, which influences the mechanical and permeability properties of structures such as the cuticle and peritrophic matrices. In this article, a new CDA encoding gene, Hacda2, was cloned by reverse transcription-polymerase chain reaction method in Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), with an open reading frame of 1,611 bp. The deduced protein composed of 536 amino acid residues with a signal peptide, a chitin-binding domain, a low-density lipoprotein receptor class A domain, and a polysaccharide deacetylase-like catalytic domain. The highest expression level of Hacda2 was detected in fat body among tissues tested in the fifth-instar larvae using real-time quantitative polymerase chain reaction method. Feeding of Bacillus thuringiensis (Bt) (Bacillales: Bacillaceae) diet changed the expression level of Hacda1, Hacda2, Hacda5a, and Hacda5b significantly and differentially in the third-instar larvae. Hacda5a and Hacda5b expression were initially down-regulated and then up-regulated, whereas, the expression level of Hacda1 and Hacda2 was suppressed constantly postfeeding on Bt diet. These results suggested that HaCDAs may be involved in the response of H. armigera larvae to Bt and may be helpful to elucidate the roles of HaCDAs in the action of Bt cry toxin. The potential of HaCDAs to be used as synergists of Bt insecticidal protein needs to be further tested. PMID:26163665

  20. Extraction of Crude Chitinase from Higher Plants and their Chitin-Hydrolysis Activities; Kotosyokubutu yurai kichinaze no chusyutu to kichin bunkai kassei

    Energy Technology Data Exchange (ETDEWEB)

    Kondo, K.; Harada, K.; Shibata, M.; Maeda, R. [Doshisha Univ., Kyoto (Japan). Faculty of Engineering

    1997-07-10

    To prepare a purified chitinase from higher plants, firstly, crude enzymes were extracted from six higher plants, namely, radish seeds, sunflower seeds, watermelon seeds, bamboo leaves, orange skin, and persimmon skin. Using these crude enzymes, pH dependencies of hydrolysis reaction of colloidal chitin are investigated. For radish seeds and bamboo leaves, which have relatively high activities, the kinetics of enzymatic reaction are studies. It is clear that these reactions obey Michaelis-Menten kinetics. 7 refs., 3 figs., 2 tabs.

  1. Optimization of chitin yield from shrimp shell waste by Bacillus subtilis and impact of gamma irradiation on production of low molecular weight chitosan.

    Science.gov (United States)

    Gamal, Rawia F; El-Tayeb, Tarek S; Raffat, Enas I; Ibrahim, Haytham M M; Bashandy, A S

    2016-10-01

    Chitin and chitosan have been produced from the exoskeletons of crustacean shells such as shrimps. In this study, seventy bacterial isolates, isolated from soil, were tested for proteolytic enzymes production. The most efficient one, identified as Bacillus subtilis, was employed to extract chitin from shrimp shell waste (SSW). Following one-variable-at-a-time approach, the relevant factors affecting deproteinization (DP) and demineralization (DM) were sucrose concentration (10%, w/v), SSW concentration (5%, w/v), inoculum size (15%, v/v), and fermentation time (6days). These factors were optimized subsequently using Box-Behnken design and response surface methodology. Maximum DP (97.65%) and DM (82.94%) were predicted at sucrose concentration (5%), SSW concentration (12.5%), inoculum size (10%, containing 35×10(8) CFU/mL), and fermentation time (7days). The predicted optimum values were verified by additional experiment. The values of DP (96.0%) and DM (82.1%) obtained experimentally correlated to the predicted values which justify the authenticity of optimum points. Overall 1.3-fold increase in DP% and DM% was obtained compared with 75.27% and 63.50%, respectively, before optimization. Gamma-irradiation (35kGy) reduced deacetylation time of irradiated chitin by 4.5-fold compared with non-irradiated chitin. The molecular weight of chitosan was decreased from 1.9×10(6) (non-irradiated) to 3.7×10(4)g/mol (at 35kGy). PMID:27267572

  2. The myosin motor domain-containing chitin synthase PdChsVII is required for development, cell wall integrity and virulence in the citrus postharvest pathogen Penicillium digitatum.

    Science.gov (United States)

    Gandía, Mónica; Harries, Eleonora; Marcos, Jose F

    2014-06-01

    Chitin is an essential component of the fungal cell wall and a potential target in the development of new antifungal compounds, due to its presence in fungi and not in plants or vertebrates. Chitin synthase genes (chs) constitute a complex family in filamentous fungi and are involved in fungal development, morphogenesis, pathogenesis and virulence. In this study, additional chs genes in the citrus postharvest pathogen Penicillium digitatum have been identified. Comparative analyses included each PdChs in each one of the classes I to VII previously established, and support the grouping of these into three divisions. Disruption of the gene coding PdChsVII, which contains a short version of a myosin motor domain, has been achieved by using Agrobacterium tumefaciens-mediated transformation and revealed its role in the life cycle of the fungus. Disruption strains were viable but showed reduced growth and conidia production. Moreover, Pdchs mutants developed morphological defects as balloon-like enlarged cells and increased chitin content, indicative of an altered cell wall structure. Gene disruption also increased susceptibility to antifungal compounds such as calcofluor white (CFW), sodium dodecyl sulfate (SDS), hydroxide peroxide (H2O2) and commercial fungicides, but significantly no change was observed in the sensitivity to antifungal peptides. The PdchsVII mutants were able to infect citrus fruit and produced tissue maceration, although had reduced virulence and most importantly were greatly impaired in the production of visible mycelium and conidia on the fruit.

  3. Ha83, a Chitin Binding Domain Encoding Gene, Is Important to Helicoverpa armigera Nucleopolyhedrovirus Budded Virus Production and Occlusion Body Assembling.

    Science.gov (United States)

    Yu, Huan; Xu, Jian; Liu, Qiang; Liu, Tong-Xian; Wang, Dun

    2015-01-01

    Helicoerpa armigera nucleopolyhedrovirus (HearNPV) ha83 is a late expressed gene that encodes a chitin binding protein. Chitin domain truncation studies revealed that the cysteine at the 128 amino acid position probably played an important role in both chitin binding ability and protein transmission of Ha83. In order to study the function of ha83 in the HearNPV infection cycle, an ha83 knockout HearNPV (Ha83KO) was constructed via homologous recombination. Viral growth and viral DNA replication curves showed that fewer budded virions were produced in Ha83KO transfected cells, while viral DNA replication was increased. Electron microscopy revealed that fewer nucleocapsids were transmitted from virogenic stroma in the Ha83KO transfected cell nucleus, and the morphology of occlusion bodies was prominently larger and cube-shaped. Furthermore, DNA quantity in occlusion bodies of Ha83KO was significantly lower than the occlusion bodies of HaWT. The transcription analysis indicated that these changes may be due to the decreased expression level of viral structural associated genes, such as polyhedrin, p10, pif-2, or cg30 in Ha83KO infected cells. Above results demonstrated that the cysteine at the 128 amino acid position in Ha83 might be the key amino acid, and Ha83 plays an important role in BVs production and OBs assembling. PMID:26057202

  4. Chitin hydrolysis assisted by cell wall degrading enzymes immobilized of Thichoderma asperellum on totally cinnamoylated D-sorbitol beads

    International Nuclear Information System (INIS)

    In this study, cell wall degrading enzymes produced by Thrichoderma asperellum (TCWDE) were immobilized on totally cinnamoylated D-sorbitol (TCNSO) beads and used for chitin hydrolysis. In order to optimize immobilization efficiency, the reaction time was varied from 2 to 12 h and reactions were conducted in the presence or absence of Na2SO4. Immobilized enzymes were analysed concerning to thermal and operational stability. Immobilization in presence of Na2SO4 was 54% more efficient than immobilization in absence of salt. After optimization, 32% of the total enzyme offered was immobilized, with 100% of bounding efficiency, measured as the relation between protein and enzyme immobilized. Free and TCNSO–TCWDE presented very similar kinetics with maximum hydrolysis reached at 90 min of reaction. Thermal stability of both free and TCNSO–TCWDE was similar, with losses in activity after 55 °C. Moreover, free and TCNSO–TCWDE retained 100% activity after 3 h incubation at 55 °C. TCNSO–TCWDE were used in a bath-wise reactor during 14 cycles, producing 1825 μg of N-acetylglucosamine (NAG) maintaining 83% of initial activity. - Highlights: • TCWDE immobilized on TCNSO, a support with highly hydrophobic character • New immobilization strategy for immobilization on a hydrophobic support • TCNSO–TCWDE were retained during washes and during incubation at 55 °C for 3 h

  5. Immobilization of Papain on Chitin and Chitosan and Recycling of Soluble Enzyme for Deflocculation of Saccharomyces cerevisiae from Bioethanol Distilleries

    Directory of Open Access Journals (Sweden)

    Douglas Fernandes Silva

    2015-01-01

    Full Text Available Yeast flocculation (Saccharomyces cerevisiae is one of the most important problems in fuel ethanol production. Yeast flocculation causes operational difficulties and increase in the ethanol cost. Proteolytic enzymes can solve this problem since it does not depend on these changes. The recycling of soluble papain and the immobilization of this enzyme on chitin or chitosan were studied. Some cross-linking agents were evaluated in the action of proteolytic activity of papain. The glutaraldehyde (0.1–10% w·v−1, polyethyleneimine (0.5% v·v−1, and tripolyphosphate (1–10% w·v−1 inactivated the enzyme in this range, respectively. Glutaraldehyde inhibited all treatments of papain immobilization. The chitosan cross-linked with TPP in 5 h of reaction showed the yield of active immobilized enzyme of 15.7% and 6.07% in chitosan treated with 0.1% PEI. Although these immobilizations have been possible, these levels have not been enough to cause deflocculation of yeast cells. Free enzyme was efficient for yeast deflocculation in dosages of 3 to 4 g·L−1. Recycling of soluble papain by centrifugation was effective for 14 cycles with yeast suspension in time perfectly compatible to industrial conditions. The reuse of proteases applied after yeast suspension by additional yeast centrifugation could be an alternative to cost reduction of these enzymes.

  6. 昆虫几丁质合成酶特性预测%Characteristics prediction of insect chitin synthase

    Institute of Scientific and Technical Information of China (English)

    陆建良; 林晨; 杨晓丽; 郑新强; 梁月荣

    2008-01-01

    利用GenBank中已公开的几丁质合成酶(chitin synthase,CS)基因序列,通过GenDoc、PROSITE Motif search和PredictProtein等软件,研究昆虫等生物CS分子特性.发现昆虫CS氨基酸序列具有CAT(M/L)WHEX3EMX3LKSI等11个保守基序,其中10个位于预测的膜内侧催化中心区域,1个位于膜外的卷曲螺旋区域.昆虫CS分子二级结构中α螺旋比例高,结构紧凑.同时C端和N端具有额外的跨膜螺旋,有利于该酶的转运和定位.位于膜外的卷曲螺旋区域可能与该酶高级结构形成和几丁质新生链组装密切相关.

  7. Investigation of the role of four mitotic septins and chitin synthase 2 for cytokinesis in Kluyveromyces lactis.

    Science.gov (United States)

    Rippert, Dorthe; Heinisch, Jürgen J

    2016-09-01

    Septins are key components of the cell division machinery from yeast to humans. The model yeast Saccharomyces cerevisiae has five mitotic septins, Cdc3, Cdc10, Cdc11, Cdc12, and Shs1. Here we characterized the five orthologs from the genetically less-redundant milk yeast Kluyveromyces lactis. We found that except for KlSHS1 all septin genes are essential. Klshs1 deletions displayed temperature-sensitive growth and morphological defects. Heterologous complementation analyses revealed that all five K. lactis genes encode functional orthologs of their S. cerevisiae counterparts. Fluorophore-tagged versions of the K. lactis septins localized to a ring at the incipient bud site and split into two separate rings at the bud neck later in cytokinesis. One of the key proteins recruited to the bud neck by septins in S. cerevisiae is the chitin synthase Chs2, which synthesizes the primary septum. KlCHS2 was found to be essential and deletions showed cytokinetic defects upon spore germination. KlChs2-GFP also localized to the bud neck and to punctate structures in K. lactis. We conclude that cytokinesis in K. lactis is similar to S. cerevisiae and chimeric septin complexes are fully functional in both yeasts. In contrast to some S. cerevisiae strains, KlChs2 and KlCdc10 were found to be essential. PMID:27422440

  8. Purification of a PHA-like chitin-binding protein from Acacia farnesiana seeds: a time-dependent oligomerization protein.

    Science.gov (United States)

    Santi-Gadelha, T; Rocha, B A M; Oliveira, C C; Aragão, K S; Marinho, E S; Gadelha, C A A; Toyama, M H; Pinto, V P T; Nagano, C S; Delatorre, P; Martins, J L; Galvani, F R; Sampaio, A H; Debray, H; Cavada, B S

    2008-07-01

    A lectin-like protein from the seeds of Acacia farnesiana was isolated from the albumin fraction, characterized, and sequenced by tandem mass spectrometry. The albumin fraction was extracted with 0.5 M NaCl, and the lectin-like protein of A. farnesiana (AFAL) was purified by ion-exchange chromatography (Mono-Q) followed by chromatofocusing. AFAL agglutinated rabbit erythrocytes and did not agglutinate human ABO erythrocytes either native or treated with proteolytic enzymes. In sodium dodecyl sulfate gel electrophoresis under reducing and nonreducing conditions, AFAL separated into two bands with a subunit molecular mass of 35 and 50 kDa. The homogeneity of purified protein was confirmed by chromatofocusing with a pI = 4.0 +/- 0.5. Molecular exclusion chromatography confirmed time-dependent oligomerization in AFAL, in accordance with mass spectrometry analysis, which confers an alteration in AFAL affinity for chitin. The protein sequence was obtained by a liquid chromatography quadrupole time-of-flight experiment and showed that AFAL has 68% and 63% sequence similarity with lectins of Phaseolus vulgaris and Dolichos biflorus, respectively. PMID:18568300

  9. Chitin hydrolysis assisted by cell wall degrading enzymes immobilized of Thichoderma asperellum on totally cinnamoylated D-sorbitol beads

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, Kátia F., E-mail: katia@icb.ufg.br [Departamento de Bioquímica e Biologia Molecular, Instituo de Ciências Biológicas, Universidade Federal de Goiás, Cx. Postal 131, 74001-970 Goiânia, GO (Brazil); Grupo de Química de Carbohidratos y Biotecnología de Alimentos (QCBA), Departamento de Química Orgánica, Facultad de Química, Universidad de Murcia, E-30100 Espinardo, Murcia (Spain); Cortijo-Triviño, David [Grupo de Química de Carbohidratos y Biotecnología de Alimentos (QCBA), Departamento de Química Orgánica, Facultad de Química, Universidad de Murcia, E-30100 Espinardo, Murcia (Spain); Batista, Karla A.; Ulhoa, Cirano J. [Departamento de Bioquímica e Biologia Molecular, Instituo de Ciências Biológicas, Universidade Federal de Goiás, Cx. Postal 131, 74001-970 Goiânia, GO (Brazil); García-Ruiz, Pedro A. [Grupo de Química de Carbohidratos y Biotecnología de Alimentos (QCBA), Departamento de Química Orgánica, Facultad de Química, Universidad de Murcia, E-30100 Espinardo, Murcia (Spain)

    2013-07-01

    In this study, cell wall degrading enzymes produced by Thrichoderma asperellum (TCWDE) were immobilized on totally cinnamoylated D-sorbitol (TCNSO) beads and used for chitin hydrolysis. In order to optimize immobilization efficiency, the reaction time was varied from 2 to 12 h and reactions were conducted in the presence or absence of Na{sub 2}SO{sub 4}. Immobilized enzymes were analysed concerning to thermal and operational stability. Immobilization in presence of Na{sub 2}SO{sub 4} was 54% more efficient than immobilization in absence of salt. After optimization, 32% of the total enzyme offered was immobilized, with 100% of bounding efficiency, measured as the relation between protein and enzyme immobilized. Free and TCNSO–TCWDE presented very similar kinetics with maximum hydrolysis reached at 90 min of reaction. Thermal stability of both free and TCNSO–TCWDE was similar, with losses in activity after 55 °C. Moreover, free and TCNSO–TCWDE retained 100% activity after 3 h incubation at 55 °C. TCNSO–TCWDE were used in a bath-wise reactor during 14 cycles, producing 1825 μg of N-acetylglucosamine (NAG) maintaining 83% of initial activity. - Highlights: • TCWDE immobilized on TCNSO, a support with highly hydrophobic character • New immobilization strategy for immobilization on a hydrophobic support • TCNSO–TCWDE were retained during washes and during incubation at 55 °C for 3 h.

  10. Stable isotope record of Holocene climate and ecological change from brine shrimp cyst chitin for the Great Salt Lake, UT

    Science.gov (United States)

    Nielson, K. E.; Bowen, G. J.

    2009-12-01

    We present a record of oxygen and hydrogen isotopes in brine shrimp cysts from the Great Salt Lake, a terminal lake in the Great Basin, US. Water balance for the region is influenced by strength of the El Niño in Pacific and by the strength of the summer monsoon. Brine shrimp cysts are a novel proxy for isotope reconstruction, and allow reconstruction of water isotopes (oxygen, hydrogen) and ecology (hydrogen). Oxygen isotopes in chitin respond to water, while both diet and growth water contribute to hydrogen isotopes, allowing reconstruction of both environmental and ecological information from a single molecule. Values of δ18O decrease from about +15‰ to about +11‰ over course of the 8000 year record. This may suggest the importance of snow melt increased over the Holocene, or it may suggest lake is larger today than it was in mid-Holocene. Hydrogen isotopes are relatively stable for most of record, fluctuating around -140‰. Modeled hydrogen isotopes in food, also stable in the beginning of the record at about -150‰, become much heavier, shifting toward about -75‰ starting about 5000 ybp. This may suggest a shift from a primarily aquatic diet in the Mid-Holocene to a diet with a greater contribution of terrestrial material later in the Holocene. These observations agree broadly with previous inferences of a warm Mid-Holocene and associated low terrestrial productivity, followed by a more moist, and consequently more productive Late Holocene.

  11. Morphological changes of the filamentous fungus Mucor mucedo and inhibition of chitin synthase activity induced by anethole.

    Science.gov (United States)

    Yutani, Masahiro; Hashimoto, Yukie; Ogita, Akira; Kubo, Isao; Tanaka, Toshio; Fujita, Ken-ichi

    2011-11-01

    trans-Anethole (anethole), a major component of anise oil, has a broad antimicrobial spectrum with antimicrobial activity relatively weaker than those of well-known antibiotics, and significantly enhances the antifungal activity of polygodial and dodecanol against the baker's yeast Saccharomyces cerevisiae and human pathogenic yeast Candida albicans. However, the antifungal mechanism of anethole is unresolved. Anethole demonstrated antifungal activity against the filamentous fungus, Mucor mucedo IFO 7684, accompanied by hyphal morphological changes such as swollen hyphae at the tips. Its minimum growth inhibitory concentration was 0.625 mM. A hyperosmotic condition (1.2 M sorbitol) restricted the induction of morphological changes, while hypoosmotic treatment (distilled water) induced bursting of hyphal tips and leakage of cytoplasmic constituents. Furthermore, anethole dose-dependently inhibited chitin synthase (CHS) activity in permeabilized hyphae in an uncompetitive manner. These results suggest that the morphological changes of M. mucedo could be explained by the fragility of cell walls caused by CHS inhibition.

  12. Regulation of the chitin degradation and utilization system by the ChiX small RNA in Serratia marcescens 2170.

    Science.gov (United States)

    Suzuki, Kazushi; Shimizu, Mari; Sasaki, Naomi; Ogawa, Chisana; Minami, Haruka; Sugimoto, Hayuki; Watanabe, Takeshi

    2016-01-01

    Serratia marcescens 2170 produces three different types of chitinases and chitin-binding protein CBP21. We found that transposon insertion into the 5' untranslated region (5' UTR) of chiPQ-ctb led to defective chitinase and CBP21 production. ChiX small RNA possessed the complementary sequence of the 5' UTRs of the chiPQ-ctb and chiR and repressed the expression of chiP and chiR. ChiX was detected in a medium containing glucose, glycerol, GlcNAc, and (GlcNAc)2, but the expression of both chiP and chiR was only observed in a medium containing (GlcNAc)2. ∆chiX mutant produced chitinases, CBP21, and chitobiase without induction. chiP transcripts were more abundant than those of chiR or chiX in a medium containing (GlcNAc)2. These results suggest that the constitutively expressed ChiX binds to the highly abundant chiP 5' UTR, thereby leading to the induction of chiR mRNA translation and the subsequent expression of chitinases and CBP21.

  13. Chitin hydrolysis assisted by cell wall degrading enzymes immobilized of Thichoderma asperellum on totally cinnamoylated D-sorbitol beads.

    Science.gov (United States)

    Fernandes, Kátia F; Cortijo-Triviño, David; Batista, Karla A; Ulhoa, Cirano J; García-Ruiz, Pedro A

    2013-07-01

    In this study, cell wall degrading enzymes produced by Thrichoderma asperellum (TCWDE) were immobilized on totally cinnamoylated D-sorbitol (TCNSO) beads and used for chitin hydrolysis. In order to optimize immobilization efficiency, the reaction time was varied from 2 to 12 h and reactions were conducted in the presence or absence of Na2SO4. Immobilized enzymes were analysed concerning to thermal and operational stability. Immobilization in presence of Na2SO4 was 54% more efficient than immobilization in absence of salt. After optimization, 32% of the total enzyme offered was immobilized, with 100% of bounding efficiency, measured as the relation between protein and enzyme immobilized. Free and TCNSO-TCWDE presented very similar kinetics with maximum hydrolysis reached at 90 min of reaction. Thermal stability of both free and TCNSO-TCWDE was similar, with losses in activity after 55 °C. Moreover, free and TCNSO-TCWDE retained 100% activity after 3h incubation at 55 °C. TCNSO-TCWDE were used in a bath-wise reactor during 14 cycles, producing 1825 μg of N-acetylglucosamine (NAG) maintaining 83% of initial activity.

  14. The efficacy of a chitin synthesis inhibitor against field populations of organophosphate-resistant Aedes aegypti in Brazil

    Directory of Open Access Journals (Sweden)

    Nathalia Giglio Fontoura

    2012-05-01

    Full Text Available The mosquito Aedes aegypti is the main focus of dengue control campaigns. Because of widespread resistance against conventional chemical insecticides, chitin synthesis inhibitors (CSIs are considered control alternatives. We evaluated the resistance status of four Brazilian Ae. aegypti populations to both the organophosphate temephos and the pyrethroid deltamethrin, which are used in Brazil to control larvae and adults, respectively. All vector populations exhibited high levels of temephos resistance and varying rates of alterations in their susceptibility to pyrethroids. The effect of the CSI novaluron on these populations was also investigated. Novaluron was effective against all populations under laboratory conditions. Field-simulated assays with partial water replacement were conducted to evaluate novaluron persistence. Bioassays were continued until an adult emergence inhibition of at least 70% was attained. We found a residual effect of eight weeks under indoor conditions and novaluron persisted for five-six weeks in assays conducted in an external area. Our data show that novaluron is effective against the Ae. aegypti populations tested, regardless of their resistance to conventional chemical insecticides.

  15. Evaluation of Three Chitin Metal Silicate Co-Precipitates as a Potential Multifunctional Single Excipient in Tablet Formulations

    Directory of Open Access Journals (Sweden)

    Rana Al-Shaikh Hamid

    2010-05-01

    Full Text Available The performance of the novel chitin metal silicate (CMS co-precipitates as a single multifunctional excipient in tablet formulation using direct compression and wet granulation methods is evaluated. The neutral, acidic, and basic drugs Spironolactone (SPL, ibuprofen (IBU and metronidazole (MET, respectively, were used as model drugs. Commercial Aldactone®, Fleximex® and Dumazole® tablets containing SPL, IBU and MET, respectively, and tablets made using Avicel® 200, were used in the study for comparison purposes. Tablets of acceptable crushing strength (>40 N were obtained using CMS. The friability values for all tablets were well below the maximum 1% USP tolerance limit. CMS produced superdisintegrating tablets (disintegration time < 1 min with the three model drugs. Regarding the dissolution rate, the sequence was as follow: CMS > Fleximex® > Avicel® 200, CMS > Avicel® 200 > Dumazole® and Aldactone® > Avicel® 200 > CMS for IBU, MET and SPL, respectively. Compressional properties of formulations were analyzed using density measurements and the compression Kawakita equation as assessment parameters. On the basis of DSC results, CMS co precipitates were found to be compatible with the tested drugs. Conclusively, the CMS co-precipitates have the potential to be used as filler, binder, and superdisintegrant, all-in-one, in the design of tablets by the direct compression as well as wet granulation methods.

  16. Chitin-Hyaluronan Nanoparticles: A Multifunctional Carrier to Deliver Anti-Aging Active Ingredients through the Skin

    Directory of Open Access Journals (Sweden)

    Pierfrancesco Morganti

    2014-07-01

    Full Text Available The paper describes the process to produce Chitin Nanofibril-Hyaluronan nanoparticles (CN-HA, showing their ability to easily load active ingredients, facilitate penetration through the skin layers, and increase their effectiveness and safety as an anti-aging agent. Size and characterization of CN-HA nanoparticles were determined by Scanning Electron Microscopy (SEM and Zetasizer, while encapsulation efficiency and loading capacity of the entrapped ingredients were controlled by chromatographic and spectrophotometric methods. Safeness was evidenced on fibroblasts and keratinocytes culture viability by the MTT (Methylthiazol assay; anti-aging activity was evaluated in vitro measuring antioxidant capacity, anti-collagenase activity, and metalloproteinase and pro-inflammatory release; efficacy was shown in vivo by a double-blind vehicle-controlled study for 60 days on 60 women affected by photo-aging. In addition, the CN-HA nanoparticles have shown interesting possibility to be used as active ingredients, for designing and making advanced medication by the electrospinning technology, as well as to produce transparent films for food packaging, by the casting method, and can be used also in their dry form as tissues or films without adding preservatives. These unusual CN-HA nanoparticles obtained from the use of raw materials of waste origin may offer an unprecedented occasion for making innovative products, ameliorating the quality of life, reducing pollution and safeguarding the environment’s integrity.

  17. In vitro bioactivity studies of larnite and larnite/chitin composites prepared from biowaste for biomedical applications

    Indian Academy of Sciences (India)

    RAJAN CHOUDHARY; SENTHIL KUMAR VENKATRAMAN; ANJALI RANA; SASIKUMAR SWAMIAPPAN

    2016-09-01

    Larnite (Ca$_2$SiO$_4$) was synthesized by the sol–gel combustion process by using raw eggshell powder as a calcium source and urea as a fuel. The main focus of this work is to convert biowaste into a biomedical material ata low-processing temperature. X-ray diffraction (XRD) pattern confirms the phase purity of the larnite and Fourier transform infrared (FTIR) spectra confirms the presence of characteristic functional groups of larnite. Scanningelectron microscopy (SEM) image shows agglomerated particles with cauliflower-like morphology and energy dispersive X-ray spectroscopy (EDX) confirms the presence of the stoichiometric ratio of required elements. Atomicforcemicroscope (AFM) images reveal the presence of pores on the surface of spherical particles. Larnite/chitin composites were fabricated into scaffold with different ratios of bioceramic to biopolymer (70:30, 80:20) to investigatethe influence of the polymer content on the apatite formation ability in simulated body fluid (SBF) medium. XRDpattern and FTIR spectra of the scaffold immersed in SBF shows apatite deposition within 5 days. The deposition ofhydroxyapatite (HAP) on the scaffold surface increases with the increase in polymer content of the composite.

  18. Purification of a thermostable chitinase from Bacillus cereus by chitin affinity and its application in microbial community changes in soil.

    Science.gov (United States)

    Liang, Tzu-Wen; Hsieh, Tung-Yen; Wang, San-Lang

    2014-06-01

    A thermostable chitinase was purified by chitin affinity from the culture supernatant of Bacillus cereus TKU028 with shrimp head powder (SHP) as the sole carbon/nitrogen source. TKU028 chitinase was purified using a one-step affinity adsorbent system, and the molecular mass of TKU028 chitinase (approximately 40 kDa) was then determined using SDS-PAGE. The enzyme was stable for 60 min at temperatures below 60 °C and stable over a broad pH range of 4-9 for 60 min. In addition, the temporal changes of a bacterial community in mangrove river sediment of the Tamsui River with added SHP were also analysed by PCR-denaturing gradient gel electrophoresis to investigate the effects of B. cereus TKU028 on the degradation of SHP. The 6-week incubation sample of SHP and B. cereus TKU028-amended mangrove river sediment displayed the highest amount of biomass, reducing sugar and total sugar, and some variance of bacterial community composition existed in the soils. PMID:24342954

  19. Control of some important soil-borne fungi by chitin associated with chilli (capsicum annuum l.) in lower sindh, pakistan

    International Nuclear Information System (INIS)

    Chilli (Capsicum annuum L.) belongs to the family Solanaceae is one of the most important cash crop of the southern parts of Pakistan. Capsicum is cultivated on a large scale in a lower region of Sindh, Pakistan. It is an important and profitable crop of Pakistan. Several biotic and abiotic stresses affect the productivity of chilli crop. It is infected by a number of diseases particularly soil-borne diseases. Surveys of soil-borne fungal diseases associated with chilli crop in different areas of lower Sindh, including, Hyderabad, Tando Allahyar, Mirpurkhas, Umerkot, Kunri, Samaro, Kot Ghulam uhammad and Digri, were conducted, and chilli plants showing symptoms of wilting were collected. A number of soil-borne root infecting fungi were isolated and identified, such as, Fusarium oxysporum, F. solani, Macrophomina phaseolina, Phytophthora capsici, Pythium sp., and Rhizoctonia solani, from collected disease plants. It was observed that all the major varieties of chillies (i.e., Sanam, Talhari, Ghotaki, Mexi), growing in lower Sindh, were highly susceptible to these fungi. The main objectives of the study were to examine the effectiveness of chitin for the management of soil-borne diseases of chilli plant by different methods, i.e., soil amendment and transplant root dip method. Results indicated that of the two methods, the soil amendment method was more effective while transplant root dip method was less effective. (author)

  20. Fluorescence microscopical studies on chitin distribution in the cell wall of giant cells of Saccharomyces uvarum, grown following X-radiaiton treatment. Fluoreszenzmikroskopische Untersuchungen zur Chitinverteilung in der Zellwand von Riesenzellen von Saccharomyces uvarum, gewachsen nach Roentgenbestrahlung

    Energy Technology Data Exchange (ETDEWEB)

    Hoschka, L.

    1982-01-01

    Teast cells are synchronized and modiated with X-rays (1.0 kGy) in the Cr, phase. Their growth behaviour is observed in suspension cultures and the formation of giant cells noted. The chitin structures are selectively stained with the fluorescent dye Calcofluor white. In the unradiated cells the chitin is deposited at the bud constriction site in the form of rings in the mother cell wall, whereas for irradiated cells only one chitin ring of normal appearance is formed between the mother cell and first bud equivalent. Between further bud equivalents an intensification of fluorescence is occasionally noted, however the organisation of the chitin into a regular ring arrangement is disturbed. In giant cells the facility for primary and secondary septa formation is missing and these are essential for successful cell division. By further experiments it was possible to identify the cause of disturbance in the cell cycle of irradiated cells. Giant cells only form one chitin ring because its DNA is replicated one time only. The major cause triggering the actual formation of giant cells must be considered the missing distribution of the once-rephicated DNA. All processes in the cell cycle dependent on this step are therefore stopped and only bud formation which occurs independently continues along its rhytmical path.

  1. Removal of dyes from water using chitosan hydrogel/SiO{sub 2} and chitin hydrogel/SiO{sub 2} hybrid materials obtained by the sol-gel method

    Energy Technology Data Exchange (ETDEWEB)

    Copello, Guillermo J. [Catedra de Quimica Analitica Instrumental, Facultad de Farmacia y Bioquimica, Universidad de Buenos Aires (UBA), Junin 956, C1113AAD Buenos Aires (Argentina); IQUIMEFA (UBA-CONICET), Junin 956, C1113AAD Buenos Aires (Argentina); Mebert, Andrea M.; Raineri, M.; Pesenti, Mariela P. [Catedra de Quimica Analitica Instrumental, Facultad de Farmacia y Bioquimica, Universidad de Buenos Aires (UBA), Junin 956, C1113AAD Buenos Aires (Argentina); Diaz, Luis E., E-mail: ldiaz@ffyb.uba.ar [Catedra de Quimica Analitica Instrumental, Facultad de Farmacia y Bioquimica, Universidad de Buenos Aires (UBA), Junin 956, C1113AAD Buenos Aires (Argentina); IQUIMEFA (UBA-CONICET), Junin 956, C1113AAD Buenos Aires (Argentina)

    2011-02-15

    This work describes the synthesis of chitosan hydrogel/SiO{sub 2} and chitin hydrogel/SiO{sub 2} hybrid mesoporous materials obtained by the sol-gel method for their use as biosorbents. Their adsorption capabilities against four dyes (Remazol Black B, Erythrosine B, Neutral Red and Gentian Violet) were compared in order to evaluate chitin as a plausible replacement for chitosan considering its efficiency and lower cost. Both chitin and chitosan were used in the form of hydrogels. This allowed full compatibility with the ethanol release from tetraethoxysilane. The hybrid materials were characterized by Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR), Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDS), Nitrogen Adsorption Isotherms and {sup 13}C solid-state Nuclear Magnetic Resonance. Adsorption experimental data were analyzed using Langmuir, Freundlich and Dubinin-Radushkevich isotherm models along with the evaluation of adsorption energy and standard free energy ({Delta}G{sup 0}). The adsorption was observed to be pH dependent. The main mechanism of dye adsorption was found to be a spontaneous charge associated interaction, except for EB adsorption on chitin/SiO{sub 2} matrix, which showed to involve a lower energy physical adsorption interaction. Aside from highly charged dyes the chitin containing matrix has similar or higher adsorption capacity than the chitosan one.

  2. Identification and Functional Characterization of a Novel OprD-like Chitin Uptake Channel in Non-chitinolytic Bacteria.

    Science.gov (United States)

    Soysa, H Sasimali M; Suginta, Wipa

    2016-06-24

    Chitoporin from the chitinolytic marine Vibrio has been characterized as a trimeric OmpC-like channel responsible for effective chitin uptake. In this study we describe the identification and characterization of a novel OprD-like chitoporin (so-called EcChiP) from Escherichia coli The gene was identified, cloned, and functionally expressed in the Omp-deficient E. coli BL21 (Omp8) Rosetta strain. On size exclusion chromatography, EcChiP had an apparent native molecular mass of 50 kDa, as predicted by amino acid sequencing and mass analysis, confirming that the protein is a monomer. Black lipid membrane reconstitution demonstrated that EcChiP could readily form stable, monomeric channels in artificial phospholipid membranes, with an average single channel conductance of 0.55 ± 0.01 nanosiemens and a slight preference for cations. Single EcChiP channels showed strong specificity, interacting with long chain chitooligosaccharides but not with maltooligosaccharides. Liposome swelling assays indicated the bulk permeation of neutral monosaccharides and showed the size exclusion limit of EcChiP to be ∼200-300 Da for small permeants that pass through by general diffusion while allowing long chain chitooligosaccharides to pass through by a facilitated diffusion process. Taking E. coli as a model, we offer the first evidence that non-chitinolytic bacteria can activate a quiescent ChiP gene to express a functional chitoporin, enabling them to take up chitooligosaccharides for metabolism as an immediate source of energy. PMID:27226611

  3. Possible transient liquid crystal phase during the laying out of connective tissues: {alpha}-chitin and collagen as models

    Energy Technology Data Exchange (ETDEWEB)

    Belamie, E; Mosser, G; Gobeaux, F; Giraud-Guille, M M [Laboratoire de Chimie de la Matiere Condensee, UMR 7574 CNRS, Universite Pierre and Marie Curie, Ecole Pratique des Hautes Etudes, 12 rue Cuvier, Paris, 75005 (France)

    2006-04-05

    Morphogenesis of extracellular matrices can be considered from different perspectives. One is that of ontogenesis, i.e., an organism's development, which is mostly concerned with the spatiotemporal regulation of genes, cell differentiation and migration. Complementary to this purely biological point of view, a physico-chemical approach can help in understanding complex mechanisms by highlighting specific events that do not require direct cellular control. Because of a structural similarity between some biological systems and liquid crystals, it was supposed that similar mechanisms could be involved. In this respect, it is important to determine the intrinsic self-assembly properties driving the ordering of biological macromolecules. Here we review in vitro studies of the condensed state of major biological macromolecules from extracellular matrices and related theories describing a mesophase transition in suspensions of rodlike particles. Dilute suspensions of collagen or chitin are isotropic, i.e., the macromolecules can take on any orientation in the fluid. Beyond a critical concentration, an ordered nematic phase appears with a higher volume fraction. The two-phase coexistence can be seen between crossed polarizers since the nematic phase is strongly birefringent and appears bright, whereas the isotropic phase remains dark. A widespread property of these structural macromolecular scaffolds is their chirality. Although the origin of chirality in colloidal suspensions is still a subject of debate, the helical nature of the cholesteric phase can be quantified. Small angle x-ray scattering performed on shear-aligned samples can help demonstrate the cholesteric nature of the anisotropic phase, inferred from optical observations. Liquid-like positional local order is revealed by the presence of broad interference peaks at low angle. The azimuthal profiles of these patterns are fitted to determine the value of the nematic order parameter at the transition. A few

  4. The Impact of Selection with Diflubenzuron, a Chitin Synthesis Inhibitor, on the Fitness of Two Brazilian Aedes aegypti Field Populations.

    Science.gov (United States)

    Belinato, Thiago Affonso; Valle, Denise

    2015-01-01

    Several Aedes aegypti field populations are resistant to neurotoxic insecticides, mainly organophoshates and pyrethroids, which are extensively used as larvicides and adulticides, respectively. Diflubenzuron (DFB), a chitin synthesis inhibitor (CSI), was recently approved for use in drinking water, and is presently employed in Brazil for Ae. aegypti control, against populations resistant to the organophosphate temephos. However, tests of DFB efficacy against field Ae. aegypti populations are lacking. In addition, information regarding the dynamics of CSI resistance, and characterization of any potential fitness effects that may arise in conjunction with resistance are essential for new Ae. aegypti control strategies. Here, the efficacy of DFB was evaluated for two Brazilian Ae. aegypti populations known to be resistant to both temephos and the pyrethroid deltamethrin. Laboratory selection for DFB resistance was then performed over six or seven generations, using a fixed dose of insecticide that inhibited 80% of adult emergence in the first generation. The selection process was stopped when adult emergence in the diflubenzuron-treated groups was equivalent to that of the control groups, kept without insecticide. Diflubenzuron was effective against the two Ae. aegypti field populations evaluated, regardless of their resistance level to neurotoxic insecticides. However, only a few generations of DFB selection were sufficient to change the susceptible status of both populations to this compound. Several aspects of mosquito biology were affected in both selected populations, indicating that diflubenzuron resistance acquisition is associated with a fitness cost. We believe that these results can significantly contribute to the design of control strategies involving the use of insect growth regulators. PMID:26107715

  5. The Impact of Selection with Diflubenzuron, a Chitin Synthesis Inhibitor, on the Fitness of Two Brazilian Aedes aegypti Field Populations.

    Directory of Open Access Journals (Sweden)

    Thiago Affonso Belinato

    Full Text Available Several Aedes aegypti field populations are resistant to neurotoxic insecticides, mainly organophoshates and pyrethroids, which are extensively used as larvicides and adulticides, respectively. Diflubenzuron (DFB, a chitin synthesis inhibitor (CSI, was recently approved for use in drinking water, and is presently employed in Brazil for Ae. aegypti control, against populations resistant to the organophosphate temephos. However, tests of DFB efficacy against field Ae. aegypti populations are lacking. In addition, information regarding the dynamics of CSI resistance, and characterization of any potential fitness effects that may arise in conjunction with resistance are essential for new Ae. aegypti control strategies. Here, the efficacy of DFB was evaluated for two Brazilian Ae. aegypti populations known to be resistant to both temephos and the pyrethroid deltamethrin. Laboratory selection for DFB resistance was then performed over six or seven generations, using a fixed dose of insecticide that inhibited 80% of adult emergence in the first generation. The selection process was stopped when adult emergence in the diflubenzuron-treated groups was equivalent to that of the control groups, kept without insecticide. Diflubenzuron was effective against the two Ae. aegypti field populations evaluated, regardless of their resistance level to neurotoxic insecticides. However, only a few generations of DFB selection were sufficient to change the susceptible status of both populations to this compound. Several aspects of mosquito biology were affected in both selected populations, indicating that diflubenzuron resistance acquisition is associated with a fitness cost. We believe that these results can significantly contribute to the design of control strategies involving the use of insect growth regulators.

  6. The Impact of Selection with Diflubenzuron, a Chitin Synthesis Inhibitor, on the Fitness of Two Brazilian Aedes aegypti Field Populations.

    Science.gov (United States)

    Belinato, Thiago Affonso; Valle, Denise

    2015-01-01

    Several Aedes aegypti field populations are resistant to neurotoxic insecticides, mainly organophoshates and pyrethroids, which are extensively used as larvicides and adulticides, respectively. Diflubenzuron (DFB), a chitin synthesis inhibitor (CSI), was recently approved for use in drinking water, and is presently employed in Brazil for Ae. aegypti control, against populations resistant to the organophosphate temephos. However, tests of DFB efficacy against field Ae. aegypti populations are lacking. In addition, information regarding the dynamics of CSI resistance, and characterization of any potential fitness effects that may arise in conjunction with resistance are essential for new Ae. aegypti control strategies. Here, the efficacy of DFB was evaluated for two Brazilian Ae. aegypti populations known to be resistant to both temephos and the pyrethroid deltamethrin. Laboratory selection for DFB resistance was then performed over six or seven generations, using a fixed dose of insecticide that inhibited 80% of adult emergence in the first generation. The selection process was stopped when adult emergence in the diflubenzuron-treated groups was equivalent to that of the control groups, kept without insecticide. Diflubenzuron was effective against the two Ae. aegypti field populations evaluated, regardless of their resistance level to neurotoxic insecticides. However, only a few generations of DFB selection were sufficient to change the susceptible status of both populations to this compound. Several aspects of mosquito biology were affected in both selected populations, indicating that diflubenzuron resistance acquisition is associated with a fitness cost. We believe that these results can significantly contribute to the design of control strategies involving the use of insect growth regulators.

  7. Preliminary assessment of the performance of oyster shells and chitin materials as adsorbents in the removal of saxitoxin in aqueous solutions

    Directory of Open Access Journals (Sweden)

    Melegari Silvia P

    2012-08-01

    Full Text Available Abstract Background This study evaluated the adsorption capacity of the natural materials chitin and oyster shell powder (OSP in the removal of saxitoxin (STX from water. Simplified reactors of adsorption were prepared containing 200 mg of adsorbents and known concentrations of STX in solutions with pH 5.0 or 7.0, and these solutions were incubated at 25°C with an orbital shaker at 200 RPM. The adsorption isotherms were evaluated within 48 hours, with the results indicating a decrease in STX concentrations in different solutions (2–16 μg/L. The kinetics of adsorption was evaluated at different contact times (0–4320 min with a decrease in STX concentrations (initial concentration of 10 μg/L. The sampling fractions were filtered through a membrane (0.20 μm and analyzed with high performance liquid chromatography to quantify the STX concentration remaining in solution. Results Chitin and OSP were found to be efficient adsorbents with a high capacity to remove STX from aqueous solutions within the concentration limits evaluated (> 50% over 18 h. The rate of STX removal for both adsorbents decreased with contact time, which was likely due to the saturation of the adsorbing sites and suggested that the adsorption occurred through ion exchange mechanisms. Our results also indicated that the adsorption equilibrium was influenced by pH and was not favored under acidic conditions. Conclusions The results of this study demonstrate the possibility of using these two materials in the treatment of drinking water contaminated with STX. The characteristics of chitin and OSP were consistent with the classical adsorption models of linear and Freundlich isotherms. Kinetic and thermodynamic evaluations revealed that the adsorption process was spontaneous (ΔGads

  8. Obtenção e caracterização de α-quitina e quitosanas de cascas de Macrobrachium rosembergii Preparation and characterization of α-chitin and chitosan from the shells of Macrobrachium rosembergii

    Directory of Open Access Journals (Sweden)

    Marcos Valério Battisti

    2008-01-01

    Full Text Available The shells of Macrobrachium rosenbergii were submitted to deproteinization (Dp and demineralization (Dm aiming the extraction of α-chitin. The different parts of the shells were processed independently by carrying out sequence 1 (Dp/Dm and sequence 2 (Dm/Dp. Both sequences allowed the extraction of chitins with low contents of calcium and magnesium, regardless of the part being processed. The sequence 1 lead to higher extraction yields while sequence 2 resulted in lower contents of inorganic compounds. Extensively deacetylated chitosans (GA<10% of medium molecular weight (0,9 x 10(5 < Mv < 2 x 10(5 g/mol resulted from the deacetylation of chitin.

  9. Synthesis of chitin and chitosan stereoisomers by thermostable α-glucan phosphorylase-catalyzed enzymatic polymerization of α-D-glucosamine 1-phosphate.

    Science.gov (United States)

    Kadokawa, Jun-ichi; Shimohigoshi, Riko; Yamashita, Kento; Yamamoto, Kazuya

    2015-04-14

    The relationship between two aminopolysaccharide stereoisomers, namely α-(1→4)- and β-(1→4)-linked (N-acetyl)-D-glucosamine polymers, is of significant interest within the field of polysaccharide science, as they correspond to amino analogs of the representative abundant natural polysaccharides, viz. amylose and cellulose. While the latter glucosamine polymer is the basis of well-known natural polysaccharides, chitin and chitosan (linear polysaccharides composed of β-(1→4)-linked N-acetyl-D-glucosamine and D-glucosamine), to the best of our knowledge, the former (α-(1→4)-linked) has not been observed in nature. For the purpose of these studies, the synthesis of such non-natural aminopolysaccharides was performed by the thermostable α-glucan phosphorylase (from Aquifex aeolicus VF5)-catalyzed enzymatic polymerization of α-D-glucosamine 1-phosphate (GlcN-1-P), via successive α-glucosaminylations, in ammonia buffer containing Mg(2+) ions, resulting in the production of the α-(1→4)-linked D-glucosamine polymers, corresponding to the structure of the chitosan stereoisomer. Subsequent N-acetylation of the products gave the aminopolysaccharides, corresponding to the chitin stereoisomer. PMID:25766841

  10. Biomedical Exploitation of Chitin and Chitosan via Mechano-Chemical Disassembly, Electrospinning, Dissolution in Imidazolium Ionic Liquids, and Supercritical Drying

    Directory of Open Access Journals (Sweden)

    Riccardo A. A. Muzzarelli

    2011-09-01

    Full Text Available Recently developed technology permits to optimize simultaneously surface area, porosity, density, rigidity and surface morphology of chitin-derived materials of biomedical interest. Safe and ecofriendly disassembly of chitin has superseded the dangerous acid hydrolysis and provides higher yields and scaling-up possibilities: the chitosan nanofibrils are finding applications in reinforced bone scaffolds and composite dressings for dermal wounds. Electrospun chitosan nanofibers, in the form of biocompatible thin mats and non-wovens, are being actively studied: composites of gelatin + chitosan + polyurethane have been proposed for cardiac valves and for nerve conduits; fibers are also manufactured from electrospun particles that self-assemble during subsequent freeze-drying. Ionic liquids (salts of alkylated imidazolium are suitable as non-aqueous solvents that permit desirable reactions to occur for drug delivery purposes. Gel drying with supercritical CO2 leads to structures most similar to the extracellular matrix, even when the chitosan is crosslinked, or in combination with metal oxides of interest in orthopedics.

  11. Antibodies against glucan, chitin, and Saccharomyces cerevisiae mannan as new biomarkers of Candida albicans infection that complement tests based on C. albicans mannan.

    Science.gov (United States)

    Sendid, B; Dotan, N; Nseir, S; Savaux, C; Vandewalle, P; Standaert, A; Zerimech, F; Guery, B P; Dukler, A; Colombel, J F; Poulain, D

    2008-12-01

    Antibodies against Saccharomyces cerevisiae mannan (ASCA) and antibodies against synthetic disaccharide fragments of glucans (ALCA) and chitin (ACCA) are biomarkers of Crohn's disease (CD). We previously showed that Candida albicans infection generates ASCA. Here, we explored ALCA and ACCA as possible biomarkers of invasive C. albicans infection (ICI). ASCA, ALCA, ACCA, and Candida mannan antigen and antibody detection tests were performed on 69 sera obtained sequentially from 18 patients with ICIs proven by blood culture, 59 sera from CD patients, 47 sera from hospitalized subjects colonized by Candida species (CZ), and 131 sera from healthy controls (HC). ASCA, ALCA, and ACCA levels in CD and ICI patients were significantly different from those in CZ and HC subjects (PALCA, ACCA, and Platelia Candida tests, 100% of ICIs were detected, with the kinetics of the antibody response depending on the patient during the time course of infection. A large number of sera presented with more than three positive tests. This is the first evidence that the detection of antibodies against chitin and glucans has diagnostic value in fungal infections and that these tests can complement more specific tests. Future trials are necessary to assess the value of these tests in multiparametric analysis, as well as their pathophysiological relevance.

  12. Application of Chitin Microbial Fertilizers in Agriculture%几丁质微生物肥料在农业上的应用

    Institute of Scientific and Technical Information of China (English)

    闫海洋; 吴海燕; 李锋; 李根; 金荣德; 王淑萍

    2012-01-01

    几丁质是一种除了纤维素之外最丰富的天然生物聚合物,含有丰富的C、N元素,能被微生物降解利用,作为一种无污染的微生物肥料供给植物生长的养分.本文综述了几丁质微生物研发的概况,介绍了几丁质的生物学功能,分析了微生物肥料的优势,重点阐述了分解几丁质微生物在现代农业上的应用,并对我国分解几丁质微生物肥料在农业上的发展前景进行了展望.%Chitin, a natural polymer of N-acetyl-D-glucosamine is exceeded in abundance only by the biopolymer cellulose. Chitin and its derivatives hold great economic value because of their versatile carbon and nitrogen contents and agrochemical applications. In this review, the development on the chitinolytic microorganisms, microbial fertilizers by chitionlytic microorganisms and their biological activities were discussed. As well as, their applications in modern agriculture was introduced and its' future was prospected.

  13. Control Effects of Chitin and Oligosaccharides on Soybean Sclerotinia Stem Rot%甲壳质和低聚糖防治大豆菌核病初探

    Institute of Scientific and Technical Information of China (English)

    王仁杰; 谢丽华

    2011-01-01

    It was recommend that spayed respectively on soybean with 2% 1 500 mL·hm-2 in flowering and pod stage.The control efficacy was 63.7%,which equaled with that of 50% Ronilan(60.1%).Using 2% chitin 3 000 mL·hm-2 could significantly improve the soybean yield.The production of soybean increased by 11.7% compared with CK,and extremely significantly higher than yield of 50% Ronilan.It suggested that using chitin and Ronilan in the control could reduce the pesticide application and stabilize the biotic agent efficacy.%甲壳质、低聚糖对大豆菌核病的防治效果研究结果表明,2%甲壳质1 500 mL.hm-2在开花期、结荚期各喷洒一遍对大豆菌核病防治效果63.7%,与农利灵防治效果相当;2%甲壳质3 000 mL.hm-2大豆增产作用明显,增产11.7%,与农利灵差异极显著。建议在大豆菌核病防治中甲壳质与农利灵混合使用,以减少化学药剂用量,稳定生物药剂防效。

  14. Chitin-Prussian blue sponges for Cs(I) recovery: From synthesis to application in the treatment of accidental dumping of metal-bearing solutions

    Energy Technology Data Exchange (ETDEWEB)

    Vincent, C. [Ecole des mines d' Alès, Centre des Matériaux des Mines d' Alès, C2MA/MPA/BCI, 6 avenue de Clavières, F-30319 Alès Cedex (France); Commissariat à l' Energie Atomique, CEA Marcoule, DEN/DTCD/SPDE/LPSD,BP 17171, F-30207 Bagnols sur Cèze (France); Barré, Y. [Commissariat à l' Energie Atomique, CEA Marcoule, DEN/DTCD/SPDE/LPSD,BP 17171, F-30207 Bagnols sur Cèze (France); Vincent, T. [Ecole des mines d' Alès, Centre des Matériaux des Mines d' Alès, C2MA/MPA/BCI, 6 avenue de Clavières, F-30319 Alès Cedex (France); Taulemesse, J.-M. [Ecole des mines d' Alès, Center des Matériaux des Mines d' Alès, 6 avenue de Clavières, F-30319 Alès Cedex (France); Robitzer, M. [Institut Charles Gerhardt – UMR5253, CNRS-UM2-ENSCM-UM1, ICGM-MACS-R2M2, 8 rue de l' Ecole Normale, F-34296 Montpellier Cedex 05 (France); Guibal, E., E-mail: Eric.Guibal@mines-ales.fr [Ecole des mines d' Alès, Centre des Matériaux des Mines d' Alès, C2MA/MPA/BCI, 6 avenue de Clavières, F-30319 Alès Cedex (France)

    2015-04-28

    Highlights: • Prussian blue microparticles incorporated in chitin sponges. • Efficient Cs(I) sorption after water absorption by dry hybrid sponge. • Water draining after sorption for metal confinement and water decontamination. • High decontamination factors and distribution coefficients for Cs(I) and {sup 137}Cs(I). • Effect of freezing conditions on porous structure and textural characterization. - Abstract: Prussian blue (i.e., iron[III] hexacyanoferrate[II], PB) has been synthesized by reaction of iron(III) chloride with potassium hexacyanoferrate and further immobilized in chitosan sponge (cellulose fibers were added in some samples to evaluate their impact on mechanical resistance). The composite was finally re-acetylated to produce a chitin-PB sponge. Experimental conditions such as the freezing temperature, the content of PB, the concentration of the biopolymer and the presence of cellulose fibers have been varied in order to evaluate their effect on the porous structure of the sponge, its water absorption properties and finally its use for cesium(I) recovery. The concept developed with this system consists in the absorption of contaminated water by the composite sponge, the in situ binding of target metal on Prussian blue load and the centrifugation of the material to remove treated water from soaked sponge. This material is supposed to be useful for the fast treatment of accidental dumping of Cs-contaminated water.

  15. Chitin and its derivatives inhibit scar formation%甲壳素及其衍生物抑制瘢痕形成:研究与进展

    Institute of Scientific and Technical Information of China (English)

    李天石; 曾文妮; 何君君

    2014-01-01

    背景:甲壳素及其衍生物抑制瘢痕形成方面的作用及机制成为近年来研究的热点。  目的:综述就近年来甲壳素及其衍生物抑制瘢痕形成的研究进展。  方法:应用计算机检索中国知网、万方数据库、维普数据库及PubMed数据库,检索有关甲壳素抑制瘢痕治疗进展的文献,检索中文关键词为“甲壳素,衍生物,瘢痕形成”,英文关键词为“Chitin; Derivatives; Scar Formation”。  结果与结论:甲壳素及其衍生物能直接或通过改变如生化因子、干扰素、肿瘤坏死因子、白细胞介素等各种因子,抑制瘢痕中成纤维细胞的增殖、分化及分泌功能;能改变伤口及瘢痕中免疫细胞的作用;能减少胶原形成,促进胶原降解;促进伤口肉芽血液循环的建立,减轻组织缺氧;促进表皮细胞和内皮细胞的生长,加速伤口愈合;抑制创面细菌繁殖,减轻感染,加速愈合。%BACKGROUND:In recent years, chitin and its derivatives have become a hotspot because of their action and mechanism of inhibiting scar formation. OBJECTIVE: To review the research progress in chitin and its derivatives that inhibit scar formation. METHODS:A computer-based search of CNKI, Wanfang, VIP and PubMed databases was performed for articles related to inhibitory effect of chitin on scar formation. The keywords were “chitin; derivatives; scar formation” in Chinese and English, respectively. RESULTS AND CONCLUSION:Chitin and its derivatives can inhibit fibroblast proliferation, differentiation and secretion in the scar directly or through altering different factors, such as biochemical factors, interferons, tumor necrosis factor, and interleukin; alter the role of immune cels in the wound and scar; reduce colagen formation and promote colagen degradation; promote the establishment of wound granulation blood circulation, thereby reducing tissue hypoxia; facilitate the growth

  16. Homologs of the Xenopus developmental gene DG42 are present in zebrafish and mouse and are involved in the synthesis of Nod-like chitin oligosaccharides during early embryogenesis.

    Science.gov (United States)

    Semino, C E; Specht, C A; Raimondi, A; Robbins, P W

    1996-05-14

    The Xenopus developmental gene DG42 is expressed during early embryonic development, between the midblastula and neurulation stages. The deduced protein sequence of Xenopus DG42 shows similarity to Rhizobium Nod C, Streptococcus Has A, and fungal chitin synthases. Previously, we found that the DG42 protein made in an in vitro transcription/translation system catalyzed synthesis of an array of chitin oligosaccharides. Here we show that cell extracts from early Xenopus and zebrafish embryos also synthesize chitooligosaccharides. cDNA fragments homologous to DG42 from zebrafish and mouse were also cloned and sequenced. Expression of these homologs was similar to that described for Xenopus based on Northern and Western blot analysis. The Xenopus anti-DG42 antibody recognized a 63-kDa protein in extracts from zebrafish embryos that followed a similar developmental expression pattern to that previously described for Xenopus. The chitin oligosaccharide synthase activity found in extracts was inactivated by a specific DG42 antibody; synthesis of hyaluronic acid (HA) was not affected under the conditions tested. Other experiments demonstrate that expression of DG42 under plasmid control in mouse 3T3 cells gives rise to chitooligosaccharide synthase activity without an increase in HA synthase level. A possible relationship between our results and those of other investigators, which show stimulation of HA synthesis by DG42 in mammalian cell culture systems, is provided by structural analyses to be published elsewhere that suggest that chitin oligosaccharides are present at the reducing ends of HA chains. Since in at least one vertebrate system hyaluronic acid formation can be inhibited by a pure chitinase, it seems possible that chitin oligosaccharides serve as primers for hyaluronic acid synthesis.

  17. Pyrolysis of chitin biomass

    DEFF Research Database (Denmark)

    Qiao, Yan; Chen, Shuai; Liu, Ying;

    2015-01-01

    , it was found that catalysts play a significant role during the pyrolysis. The gaseous evolution components, including NH3, H2O, CO, and CO2 were observed by on line MS. The experimental results disclosed that the obtained carbonaceous materials had lost the original hydrocarbon structure totally...

  18. Biodegradable chitin conduit tubulation combined with bone marrow mesenchymal stem cell transplantation for treatment of spinal cord injury by reducing glial scar and cavity formation

    Directory of Open Access Journals (Sweden)

    Feng Xue

    2015-01-01

    Full Text Available We examined the restorative effect of modified biodegradable chitin conduits in combination with bone marrow mesenchymal stem cell transplantation after right spinal cord hemisection injury. Immunohistochemical staining revealed that biological conduit sleeve bridging reduced glial scar formation and spinal muscular atrophy after spinal cord hemisection. Bone marrow mesenchymal stem cells survived and proliferated after transplantation in vivo, and differentiated into cells double-positive for S100 (Schwann cell marker and glial fibrillary acidic protein (glial cell marker at 8 weeks. Retrograde tracing showed that more nerve fibers had grown through the injured spinal cord at 14 weeks after combination therapy than either treatment alone. Our findings indicate that a biological conduit combined with bone marrow mesenchymal stem cell transplantation effectively prevented scar formation and provided a favorable local microenvironment for the proliferation, migration and differentiation of bone marrow mesenchymal stem cells in the spinal cord, thus promoting restoration following spinal cord hemisection injury.

  19. Biodegradable chitin conduit tubulation combined with bone marrow mesenchymal stem cell transplantation for treatment of spinal cord injury by reducing glial scar and cavity formation

    Institute of Scientific and Technical Information of China (English)

    Feng Xue; Er-jun Wu; Pei-xun Zhang; Li-ya A; Yu-hui Kou; Xiao-feng Yin; Na Han

    2015-01-01

    We examined the restorative effect of modiifed biodegradable chitin conduits in combination with bone marrow mesenchymal stem cell transplantation after right spinal cord hemisection injury. Immunohistochemical staining revealed that biological conduit sleeve bridging reduced glial scar formation and spinal muscular atrophy after spinal cord hemisection. Bone marrow mesenchymal stem cells survived and proliferated after transplantationin vivo, and differentiated into cells double-positive for S100 (Schwann cell marker) and glial ifbrillary acidic protein (glial cell marker) at 8 weeks. Retrograde tracing showed that more nerve ifbers had grown through the injured spinal cord at 14 weeks after combination therapy than either treatment alone. Our ifndings indicate that a biological conduit combined with bone marrow mesenchymal stem cell transplantation effectively prevented scar formation and provided a favorable local microenvi-ronment for the proliferation, migration and differentiation of bone marrow mesenchymal stem cells in the spinal cord, thus promoting restoration following spinal cord hemisection injury.

  20. Preparation of silver nano-particles immobilized onto chitin nano-crystals and their application to cellulose paper for imparting antimicrobial activity.

    Science.gov (United States)

    Li, Zhihan; Zhang, Ming; Cheng, Dong; Yang, Rendang

    2016-10-20

    Immobilized silver nano-particles (Ag NPs) possess excellent antimicrobial properties due to their unique surface characteristics. In this paper, immobilized silver nano-particles were synthesized in the presence of chitin nano-crystals (CNC) based on the Tollens mechanism (reduction of silver ion by aldehydes in the chitosan oligosaccharides (COS)) under microwave-assisted conditions. The prepared Ag NPs-loaded CNC nano-composites were then applied onto the paper surface via coating for the preparation of antibacterial paper. Fourier transform infrared (FT-IR) and X-ray diffraction (XRD) results confirmed that the Ag NPs were immobilized onto the CNC. The transmission electron microscope (TEM) and scanning electron microscopy (SEM) results further revealed that the spherical Ag NPs (5-12nm) were well dispersed on the surface of CNC. The coated paper made from the Ag NPs-loaded CNC nano-composites exhibited a high effectiveness of the antibacterial activity against E. coli or S. aureus.

  1. Mo-CBP3, an antifungal chitin-binding protein from Moringa oleifera seeds, is a member of the 2S albumin family.

    Directory of Open Access Journals (Sweden)

    José E C Freire

    Full Text Available Mo-CBP3 is a chitin-binding protein from M. oleifera seeds that inhibits the germination and mycelial growth of phytopathogenic fungi. This protein is highly thermostable and resistant to pH changes, and therefore may be useful in the development of new antifungal drugs. However, the relationship of MoCBP3 with the known families of carbohydrate-binding domains has not been established. In the present study, full-length cDNAs encoding 4 isoforms of Mo-CBP3 (Mo-CBP3-1, Mo-CBP3-2, Mo-CBP3-3 and Mo-CBP3-4 were cloned from developing seeds. The polypeptides encoded by the Mo-CBP3 cDNAs were predicted to contain 160 (Mo-CBP3-3 and 163 amino acid residues (Mo-CBP3-1, Mo-CBP3-2 and Mo-CBP3-4 with a signal peptide of 20-residues at the N-terminal region. A comparative analysis of the deduced amino acid sequences revealed that Mo-CBP3 is a typical member of the 2S albumin family, as shown by the presence of an eight-cysteine motif, which is a characteristic feature of the prolamin superfamily. Furthermore, mass spectrometry analysis demonstrated that Mo-CBP3 is a mixture of isoforms that correspond to different mRNA products. The identification of Mo-CBP3 as a genuine member of the 2S albumin family reinforces the hypothesis that these seed storage proteins are involved in plant defense. Moreover, the chitin-binding ability of Mo-CBP3 reveals a novel functionality for a typical 2S albumin.

  2. Aspergillus nidulans class V and VI chitin synthases CsmA and CsmB, each with a myosin motor-like domain, perform compensatory functions that are essential for hyphal tip growth.

    Science.gov (United States)

    Takeshita, Norio; Yamashita, Shuichi; Ohta, Akinori; Horiuchi, Hiroyuki

    2006-03-01

    The polarized synthesis of cell wall components such as chitin is essential for the hyphal tip growth of filamentous fungi. The actin cytoskeleton is known to play important roles in the determination of hyphal polarity in Aspergillus nidulans. Previously, we suggested that CsmA, a chitin synthase with a myosin motor-like domain (MMD), was involved in polarized chitin synthesis in a manner dependent on the interaction between the MMD and the actin cytoskeleton. The genome database indicates that A. nidulans possesses another gene encoding another chitin synthase with an MMD. In this study, we characterized this gene, which we designated csmB. The csmB null mutants examined were viable, although they exhibited defective phenotypes, including the formation of balloons and intrahyphal hyphae and the lysis of subapical regions, which were similar to those obtained with csmA null mutants. Moreover, csmA csmB double null mutants were not viable. Mutants in which csmB was deleted and the expression of csmA was under the control of the alcA promoter were viable but severely impaired in terms of hyphal growth under alcA-repressing conditions. We revealed that CsmB with three copies of a FLAG epitope tag localized at the hyphal tips and forming septa, and that the MMD of CsmB was able to bind to actin filaments in vitro. These results suggest that CsmA and CsmB perform compensatory functions that are essential for hyphal tip growth.

  3. Culturable autochthonous gut bacteria in Atlantic salmon (Salmo salar L.) fed diets with or without chitin. Characterization by 16S rRNA gene sequencing, ability to produce enzymes and in vitro growth inhibition of four fish pathogens

    OpenAIRE

    Askarian, Fatemeh; Zhou, Zhigang; Olsen, Rolf Erik; Sperstad, Sigmund; Ringø, Einar

    2011-01-01

    The present investigation evaluated the effect of chitin (5% supplementation) on the adherent aerobic intestinal microbiota of Atlantic salmon (Salmo salar L.). One hundred and seventy three isolates were isolated but 34 isolates died prior to positive identification. Sixty four out of 139 autochthonous gut bacteria were further identified by 16S rRNA gene sequencing and further tested for protease, amylase, cellulase, phytase, lipase and chitinase activities. Moreover, the most promising enz...

  4. Chitin sesame oil beeswax cream in promoting diabetes foot healing coagulant research progress%甲壳素麻油蜂蜡膏促进糖尿病足创面愈合的研究进展

    Institute of Scientific and Technical Information of China (English)

    李炳辉; 冯自波; 高瑞超

    2011-01-01

    It is an important clinical work to use appropriate dressings and good create wound healing environment were created for the chronic wounds. Years of clinical application showed that chitin sesame oil beeswax creams had the effect promoting chronic wounds healing ( including diabetes foot ulcer ). Chitin, sesame oil and beeswax could promote the surface wound healing effectively. Chitin sesame oil beeswax cream promote wound healing more effectively and its application would provide more choice for the clinical dressing.%慢性创面(包括糖尿病足溃疡)合适敷料的应用,创造良好的伤口愈合环境,是临床工作面临的课题.甲壳素、麻油、蜂蜡能有效促进体表创面的愈合,甲壳素麻油蜂蜡膏更能有效促进创面的愈合,为临床敷料的应用提供更多的选择.

  5. Potentiation of the synergistic activities of chitinases ChiA, ChiB and ChiC from Serratia marcescens CFFSUR-B2 by chitobiase (Chb) and chitin binding protein (CBP).

    Science.gov (United States)

    Gutiérrez-Román, Martha Ingrid; Dunn, Michael F; Tinoco-Valencia, Raunel; Holguín-Meléndez, Francisco; Huerta-Palacios, Graciela; Guillén-Navarro, Karina

    2014-01-01

    With the goal of understanding the chitinolytic mechanism of the potential biological control strain Serratia marcescens CFFSUR-B2, genes encoding chitinases ChiA, ChiB and ChiC, chitobiase (Chb) and chitin binding protein (CBP) were cloned, the protein products overexpressed in Escherichia coli as 6His-Sumo fusion proteins and purified by affinity chromatography. Following affinity tag removal, the chitinolytic activity of the recombinant proteins was evaluated individually and in combination using colloidal chitin as substrate. ChiB and ChiC were highly active while ChiA was inactive. Reactions containing both ChiB and ChiC showed significantly increased N-acetylglucosamine trimer and dimer formation, but decreased monomer formation, compared to reactions with either enzyme alone. This suggests that while both ChiB and ChiC have a general affinity for the same substrate, they attack different sites and together degrade chitin more efficiently than either enzyme separately. Chb and CBP in combination with ChiB and ChiC (individually or together) increased their chitinase activity. We report for the first time the potentiating effect of Chb on the activity of the chitinases and the synergistic activity of a mixture of all five proteins (the three chitinases, Chb and CBP). These results contribute to our understanding of the mechanism of action of the chitinases produced by strain CFFSUR-B2 and provide a molecular basis for its high potential as a biocontrol agent against fungal pathogens.

  6. Clarification of Health-promoting Vinegar and Fruit Vinegar by a Chitin-Maifanshi Complex%甲壳素负载麦饭石复合物对保健食醋和果醋的澄清作用

    Institute of Scientific and Technical Information of China (English)

    卢维奇; 陈忻; 丁家良; 蓝梦玉; 居本旺

    2011-01-01

    A composite chitin-maifanshi clarifier was developed mainly based on chitin,a naturally occurring high molecular weight polymer.The solid clarifier was prepared as a mixture of 80-mesh maifanshi and 0.5% chitin in 1 mol/L hydrochloric acid solution at a ratio of 1:1.2(g/mL) and used to clarify health-promoting vinegar and fruit vinegar.Stirring for 6 min at room temperature after addition of the clarifier at 1.0 g/100 mL was found optimal.When used separately,both chitin and maifanshi could clarify health-promoting vinegar and fruit vinegar.Better results were obtained using the composite clarifier as a result of the synergistic effect between chitin and maifanshi.Clarified health-promoting vinegar was a transparent amber-color liquid.Fruit vinegar could be better clarified by the composite clarifier than health-promoting vinegar.Moreover,little effect on the nutrient composition of fruit vinegar was observed.These results demonstrate that the composite clarifier is an excellent clarifier.%将天然高分子甲壳素作为澄清剂的主体,研制甲壳素-麦饭石复合澄清剂。将80目麦饭石与甲壳素的0.5%盐酸溶液按1:1.2(g/mL)混合制成固体复合澄清剂,用其来处理保健食醋和果醋。得出最佳澄清工艺条件:澄清剂添加量1.0g/100mL、室温搅拌6min。分别用甲壳素、麦饭石对保健食醋和果醋都有一定的澄清效果,而复合澄清剂中的甲壳素与麦饭石的良好的澄清作用相互促进,澄清效果更加显著。澄清后的保健食醋具有琥珀色透明液体。甲壳素-麦饭石复合澄清剂对果醋的澄清效果比保健食醋更加显著,对其他营养成分的影响较小,说明甲壳素-麦饭石复合澄清剂是一种优良的澄清剂。

  7. Identification of Albizia lebbeck seed coat chitin-binding vicilins (7S globulins with high toxicity to the larvae of the bruchid Callosobruchus maculatus

    Directory of Open Access Journals (Sweden)

    A.J. Souza

    2012-02-01

    Full Text Available Seed coat is a specialized maternal tissue that interfaces the embryo and the external environment during embryogenesis, dormancy and germination. In addition, it is the first defensive barrier against penetration by pathogens and herbivores. Here we show that Albizia lebbeck seed coat dramatically compromises the oviposition, eclosion and development of the bruchid Callosobruchus maculatus. Dietary supplementation of bruchid larvae with A. lebbeck seed coat flour causes severe weight loss and reduces survival. By means of protein purification, mass spectrometry and bioinformatic analyses, we show that chitin-binding vicilins are the main source of A. lebbeck tegumental toxicity to C. maculatus. At concentrations as low as 0.1%, A. lebbeck vicilins reduce larval mass from 8.1 ± 1.7 (mass of control larvae to 1.8 ± 0.5 mg, which corresponds to a decrease of 78%. Seed coat toxicity constitutes an efficient defense mechanism, hindering insect predation and preventing embryo damage. We hypothesize that A. lebbeck vicilins are good candidates for the genetic transformation of crop legumes to enhance resistance to bruchid predation.

  8. Chitin-Prussian blue sponges for Cs(I) recovery: from synthesis to application in the treatment of accidental dumping of metal-bearing solutions.

    Science.gov (United States)

    Vincent, C; Barré, Y; Vincent, T; Taulemesse, J-M; Robitzer, M; Guibal, E

    2015-04-28

    Prussian blue (i.e., iron[III] hexacyanoferrate[II], PB) has been synthesized by reaction of iron(III) chloride with potassium hexacyanoferrate and further immobilized in chitosan sponge (cellulose fibers were added in some samples to evaluate their impact on mechanical resistance). The composite was finally re-acetylated to produce a chitin-PB sponge. Experimental conditions such as the freezing temperature, the content of PB, the concentration of the biopolymer and the presence of cellulose fibers have been varied in order to evaluate their effect on the porous structure of the sponge, its water absorption properties and finally its use for cesium(I) recovery. The concept developed with this system consists in the absorption of contaminated water by the composite sponge, the in situ binding of target metal on Prussian blue load and the centrifugation of the material to remove treated water from soaked sponge. This material is supposed to be useful for the fast treatment of accidental dumping of Cs-contaminated water. PMID:25646900

  9. A WDR Gene Is a Conserved Member of a Chitin Synthase Gene Cluster and Influences the Cell Wall in Aspergillus nidulans

    Science.gov (United States)

    Guerriero, Gea; Silvestrini, Lucia; Obersriebnig, Michael; Hausman, Jean-Francois; Strauss, Joseph; Ezcurra, Inés

    2016-01-01

    WD40 repeat (WDR) proteins are pleiotropic molecular hubs. We identify a WDR gene that is a conserved genomic neighbor of a chitin synthase gene in Ascomycetes. The WDR gene is unique to fungi and plants, and was called Fungal Plant WD (FPWD). FPWD is within a cell wall metabolism gene cluster in the Ascomycetes (Pezizomycotina) comprising chsD, a Chs activator and a GH17 glucanase. The FPWD, AN1556.2 locus was deleted in Aspergillus nidulans strain SAA.111 by gene replacement and only heterokaryon transformants were obtained. The re-annotation of Aspergilli genomes shows that AN1556.2 consists of two tightly linked separate genes, i.e., the WDR gene and a putative beta-flanking gene of unknown function. The WDR and the beta-flanking genes are conserved genomic neighbors localized within a recently identified metabolic cell wall gene cluster in genomes of Aspergilli. The heterokaryons displayed increased susceptibility to drugs affecting the cell wall, and their phenotypes, observed by optical, confocal, scanning electron and atomic force microscopy, suggest cell wall alterations. Quantitative real-time PCR shows altered expression of some cell wall-related genes. The possible implications on cell wall biosynthesis are discussed. PMID:27367684

  10. Expression of Ciona intestinalis variable region-containing chitin-binding proteins during development of the gastrointestinal tract and their role in host-microbe interactions.

    Directory of Open Access Journals (Sweden)

    Assunta Liberti

    Full Text Available Variable region-containing chitin-binding proteins (VCBPs are secreted, immune-type molecules that have been described in both amphioxus, a cephalochordate, and sea squirt, Ciona intestinalis, a urochordate. In adult Ciona, VCBP-A, -B and -C are expressed in hemocytes and the cells of the gastrointestinal tract. VCBP-C binds bacteria in the stomach lumen and functions as an opsonin in vitro. In the present paper the expression of VCBPs has been characterized during development using in situ hybridization, immunohistochemical staining and quantitative polymerase chain reaction (qPCR technologies. The expression of VCBP-A and -C is detected first in discrete areas of larva endoderm and becomes progressively localized during differentiation in the stomach and intestine, marking the development of gut tracts. In "small adults" (1-2 cm juveniles expression of VCBP-C persists and VCBP-A gradually diminishes, ultimately replaced by expression of VCBP-B. The expression of VCBP-A and -C in stage 7-8 juveniles, at which point animals have already started feeding, is influenced significantly by challenge with either Gram-positive or -negative bacteria. A potential role for VCBPs in gut-microbiota interactions and homeostasis is indicated.

  11. Identification and characterization of a chitin-binding protein purified from coelomic fluid of the lugworm Arenicola marina defining a novel protein sequence family

    DEFF Research Database (Denmark)

    Vitashenkova, Nina; Moeller, Jesper Bonnet; Leth-Larsen, Rikke;

    2012-01-01

    , respectively, were isolated from a coelomocyte cDNA library. The two clones designated AML-1a and AML-1b were 92% identical at the protein level, and represent a novel type of protein sequence family. Purified AML-1 induced agglutination of rabbit erythrocytes, which could be inhibited by N......-acetylated saccharides. Recombinant AML-1b showed the same band pattern as the native protein, whereas recombinant AML-1a reduced lacked a 27-kDa band. AML-1b bound GlcNAc-derivatized columns and chitin, whereas AML-1a did not bind to these matrices. Immunohistochemical analysis revealed, that AML-1 is expressed...... by coelomocytes, in the nephridium and in round cells in epidermis and in eggs. Moreover, AML-1 expression was up-regulated in response to a parasitic infection. We conclude that AML-1 purified from coelomic fluid is encoded by AML-1b and represents a novel type of protein family that binds acetylated components....

  12. Biomaterials based on freeze dried surface-deacetylated chitin nanofibers reinforced with sulfobutyl ether β-cyclodextrin gel in wound dressing applications.

    Science.gov (United States)

    Tabuchi, Ryo; Azuma, Kazuo; Izumi, Ryotaro; Tanou, Tsubasa; Okamoto, Yoshiharu; Nagae, Tomone; Iohara, Daisuke; Uekama, Kaneto; Otagiri, Masaki; Hirayama, Fumitoshi; Ifuku, Shinsuke; Anraku, Makoto

    2016-09-25

    A freeze-dried gel composed of surface-deacetylated chitin nanofibers (SDACNFs), reinforced with an anionic cyclodextrin, sulfobutyl ether β-cyclodextrin (SBE-β-CD) was evaluated for treating wounds in a rat model, and the results were compared with a SDACNFs gel without SBE-β-CD. The incorporation of prednisolone (PD), a poorly water-soluble drug, in both types of gels and its release from the gels were also compared. In both cases, wound areas were decreased and their effect was higher than that of commercially available wound dressings. The rate of release of PD from the freeze-dried SDACNFs/SBE-β-CD was much faster than that form SDACNFs alone without SBE-β-CD, due to fact that the PD is more soluble in the amorphous SBE-β-CD complex compared to the other preparations. The findings indicate that the freeze-dried SDACNFs/SBE-β-CD gel would be beneficial as a new biomaterial for the treatment of wounds and for preparing homogeneous high-content gels that contain poorly water-soluble drugs. PMID:27521704

  13. A chitin deacetylase-like protein is a predominant constituent of tick peritrophic membrane that influences the persistence of Lyme disease pathogens within the vector.

    Directory of Open Access Journals (Sweden)

    Toru Kariu

    Full Text Available Ixodes scapularis is the specific arthropod vector for a number of globally prevalent infections, including Lyme disease caused by the bacterium Borrelia burgdorferi. A feeding-induced and acellular epithelial barrier, known as the peritrophic membrane (PM is detectable in I. scapularis. However, whether or how the PM influences the persistence of major tick-borne pathogens, such as B. burgdorferi, remains largely unknown. Mass spectrometry-based proteome analyses of isolated PM from fed ticks revealed that the membrane contains a few detectable proteins, including a predominant and immunogenic 60 kDa protein with homology to arthropod chitin deacetylase (CDA, herein termed I. scapularis CDA-like protein or IsCDA. Although IsCDA is primarily expressed in the gut and induced early during tick feeding, its silencing via RNA interference failed to influence either the occurrence of the PM or spirochete persistence, suggesting a redundant role of IsCDA in tick biology and host-pathogen interaction. However, treatment of ticks with antibodies against IsCDA, one of the most predominant protein components of PM, affected B. burgdorferi survival, significantly augmenting pathogen levels within ticks but without influencing the levels of total gut bacteria. These studies suggested a preferential role of tick PM in limiting persistence of B. burgdorferi within the vector. Further understanding of the mechanisms by which vector components contribute to pathogen survival may help the development of new strategies to interfere with the infection.

  14. Optimization of the Extraction Process of Chitin from Shrimp Shell and Its Anti-diabetic Activity%虾壳甲壳素提取工艺优化及其辅助降血糖活性研究

    Institute of Scientific and Technical Information of China (English)

    孟凡欣; 吴丽艳; 徐盼菊; 滕利荣; 董媛

    2016-01-01

    In order to extract chitin from shrimp shell and investigate it's hypoglycemic effect , response surface method and desirability function were applied to optimism the extraction process of chitin from shrimp shell. Then the hypoglycemic effect of chitin was studied. The diabetic mice model was established by using alloxan. After one month's treatment,the hepoglycemic effects of chitin,metformin and chitin combined with metformin on the body weight,blood glucose and so on were studied. The optimum extraction condition of chitin was as fol-low:pH 11,EDTA concentration 11%,reaction time 2 h,solid-liquid ratio 1∶14 (g/mL),after filtration,dry-ing,hydrogen peroxide bleaching and drying,vested chitin extract. Compared verification tests with the model predictive value,the relative error was 2.8%which was improved by 20.3%. The hypoglycemic results showed that,compared with the model group,or the chitin and metformin alone,the combination of the two drugs could relieve the weight loss of mice induced by diabetes mellitus (P<0.05),and the serum total cholesterol,triglyc-eride,blood glucose levels were significantly reduced (P<0.01,P<0.01,P<0.01,P<0.01). The insulin expression increased (P<0.05). The mouse organ index showed that the combined administration of chitin and metformin could also relieve the damage to the pancreas tissue (P<0.05). Chitin can enhance the efficacy of metformin in lowering blood glucose and blood lipid ,and it has important significance in clinical application.%优化了虾壳中甲壳素提取工艺及其对糖尿病小鼠的影响。首先采用期望函数和响应面法优化了EDTA提取虾壳脱钙脱蛋白质工艺,并通过四氧嘧啶建立糖尿病小鼠模型,分别考察甲壳素、二甲双胍和二者联合给药1个月后,糖尿病小鼠的体重、血糖等指标的变化。最终确定最佳提取工艺为:EDTA脱钙条件pH 11,EDTA浓度11%,反应时间2 h,料液比1∶14(g/mL),之后过滤,烘干,双氧

  15. 壳聚糖-HCG缓释制剂对鱼类生殖内分泌机能的影响%STUDIES ON THE EFFECTS OF SUSTAINED-RELEASE DELIVERY SYSTEMS OF CHITIN-HUMAN CHORIONIC GONADOTROPIN (CHITIN-HCG) ON REPRODUCTION ENDOCRINE FUNCTION OFGOLDFISH (CARASSIUS AURATUSL. VAR)

    Institute of Scientific and Technical Information of China (English)

    侯志帅; 温海深; 尹相菡

    2014-01-01

    以壳聚糖为原料制备壳聚糖-HCG 缓释制剂,进行激素埋植实验,间隔一定时间检测雌和雄鱼性腺发育、血清主要性激素含量和繁殖内分泌相关基因表达特征。结果表明:在埋植壳聚糖-HCG 缓释激素后,雌鱼性成熟系数(GSI)、血清睾酮(T)水平、血清雌二醇(E2)水平在6-30d内较对照组效果明显;雄鱼GSI仅在第6天显著高于对照组,血清T水平在第2、第14天高于对照组。血清E2水平在实验期间与对照组无显著差异。RT-PCR结果显示:性腺型P450芳香化酶(CYP19A)在性腺中表达丰富,心脏中最少。雌鱼性腺P450芳香化酶(CYP19A)基因mRNA相对表达量在第2、第6天显著高于对照组,雄鱼在第6天显著高于对照,雌鱼性腺雌激素受体(ERα)基因mRNA相对表达量在14-30d显著高于对照组,雄鱼在第6至第21天显著高于对照组。研究表明,壳聚糖-HCG 缓释制剂一次埋植后可在21d 内稳定持久地释放激素,对调节鱼类的生殖机能具有良好的促进效果。%With Sustained-release delivery systems of Chitin-Human Chorionic Gonadotropin (Chitin-HCG), at regular intervals after implantation of Chitin-HCG, we detected the gonadal developments, the levels of major sex hormones in serum and the relative expression levels of genes for reproduction endocrine function of female and male fish. The re-sults showed that implanted the Chitin-HCG, the gonado-somatic index (GSI), levels of testosterone (T) and estradiol (E2) of female fish were more effective than the controlled group from the 6th day to the 30th day. TheGSIof male fish was significantly higher than the controlled group only at the 6th day after implantation. The levels of testosterone (T) of male fish were significantly higher than the controlled group at the 2nd and the 14th day after implantation and the levels of estradiol (E2) of male fish showed no significant difference with the controlled group. With the RT

  16. New insights into the structure and mode of action of Mo-CBP3, an antifungal chitin-binding protein of Moringa oleifera seeds.

    Directory of Open Access Journals (Sweden)

    Adelina B Batista

    Full Text Available Mo-CBP3 is a chitin-binding protein purified from Moringa oleifera Lam. seeds that displays inhibitory activity against phytopathogenic fungi. This study investigated the structural properties and the antifungal mode of action of this protein. To this end, circular dichroism spectroscopy, antifungal assays, measurements of the production of reactive oxygen species and microscopic analyses were utilized. Mo-CBP3 is composed of 30.3% α-helices, 16.3% β-sheets, 22.3% turns and 30.4% unordered forms. The Mo-CBP3 structure is highly stable and retains its antifungal activity regardless of temperature and pH. Fusarium solani was used as a model organism for studying the mechanisms by which this protein acts as an antifungal agent. Mo-CBP3 significantly inhibited spore germination and mycelial growth at 0.05 mg.mL-1. Mo-CBP3 has both fungistatic and fungicidal effects, depending on the concentration used. Binding of Mo-CBP3 to the fungal cell surface is achieved, at least in part, via electrostatic interactions, as salt was able to reduce its inhibitory effect. Mo-CBP3 induced the production of ROS and caused disorganization of both the cytoplasm and the plasma membrane in F. solani cells. Based on its high stability and specific toxicity, with broad-spectrum efficacy against important phytopathogenic fungi at low inhibitory concentrations but not to human cells, Mo-CBP3 has great potential for the development of new antifungal drugs or transgenic crops with enhanced resistance to phytopathogens.

  17. Improved technique for preparation of deacetylated chitin%脱乙酰甲壳质制备工艺的改进

    Institute of Scientific and Technical Information of China (English)

    凌沛学; 荣晓花; 张天民; 员象敏

    2007-01-01

    简单,反应条件更温和,且所得脱乙酰甲壳质质量明显提高.%BACKGROUND: The application of deacetylated chitin (chitosan, DC) prepared by traditional technique was limited because of its lower degree of deacetylation, impurity and relative lower molecular mass.OBJECTIVE: To improve the traditional technique for extraction and preparation of DC from the rustae f oratosquila oratoria.DESIGN: Contrasting observation.SETTING: Shandong Institute of Biopharmaceutics.MATERIALS: The experiment was carried out in the Shandong Key Laboratory for iopharmaceutics, Shandong Institute of Biopharmaceutics from February 2003 to January 2004. Experimental nstrument: Mettler AE240 electronic analytical balance and ZK-40AB electrothermal vacuum drying oven were rovided by Mettler-Toledo Instruments Co., Ltd. And ShangHai Shuli Instruments Co.,Ltd., respectively. Xperimental materials: oratosquila oratoria was purchased from Jinan aquatic products market.METHODS: ①C as traditionally prepared from chitin by decoloring with strong oxidant and deacetylating with concentrated alkaline liquor under high temperature. Chitin was extracted from crustae of shrimp and crab fter decalcification with diluted acid and deproteinization with diluted base. ②The improved preparation echnique: The crustae of oratosquila oratoria was decalcificated and decolorized with diluted acid, and as deproteinized and decolorized with diluted base at room temperature, and then the chitin was obtained fter the second decalcification and decolorization with diluted acid. The crude DC was obtained from hitin after deacetylation and decolorization with concentrated ase at 55-65 ℃. The crude DC was issolved n diluted acid and filtered. The filtrate was collected, precipitated with dilute base. After filtering, he sediments were retained, washed with water and dried. Then pure DC was obtained.MAIN OUTCOME MEASURES: he comparison between improved technique and traditional technique; Color

  18. 过硫酸钾引发羧甲基甲壳素和丙烯酸钾溶液接枝聚合%Graft copolymerization of potassium acrylate with carboxymethyl chitin

    Institute of Scientific and Technical Information of China (English)

    王芳宁; 孙宾宾; 杨博

    2009-01-01

    以过硫酸钾为引发剂.水为介质,制备了羧甲基甲壳素接枝丙烯酸钾共聚物,讨论了反应温度、反应时间、引发剂用量、单体用量对接枝率的影响,获得了最佳反应条件.结果表明:在含羧甲基甲壳素0.3g的30.0 mL水溶液中,加入过硫酸钾50.0 mg,丙烯酸钾水溶液8.0 mL,于60℃反应120 min时接枝率最高,达305.1%.接枝共聚物具有水溶性.接枝共聚改性反应可以扩展羧甲基甲壳素的应用价值.%Using potassium persulfate as initiator, the graft copolymer of potassium acrylate and carboxymethyl chitin was prepared in water solution. The effect of reaction temperature、reaction time、amount of initiator、amount of monomer on graft copolymerization were studied. The optimum condition with the maximum of percentage of grafting was shown as following: in 30.0 mL water solution with 0.3 g carboxymethyl chitin, added potassium persulfate 50.0 mg, potassium acrylate solution 8.0 mL, at 60℃, reaction time 120 min, the maximum percentage of grafting was 305.1%. The graft eopolymer was water-soluble. The graft copolymerization of carboxymethyi chitin can make it more useful.

  19. Curative effect observation of chitin medical wound paste for postoperative incision healing of circumcision%甲壳质医用创面贴对包皮环切术后切口愈合的疗效观察

    Institute of Scientific and Technical Information of China (English)

    邓敏

    2014-01-01

    目的:观察甲壳质医用创面贴用于包皮环切术后对切口愈合的疗效。方法120例包皮环切患者随机分为两组,观察组于包皮环切后用甲壳质医用创面贴贴敷切口;对照组术后采用常规纱布敷料包扎处理伤口。结果观察组切口愈合情况明显优于对照组(P<0.05),术后并发症的发生明显降低(P<0.05)。结论包皮环切后应用甲壳质医用创面贴安全有效,具有良好的促进切口愈合、减少切口水肿及预防感染和瘢痕发生的治疗效果,值得推广。%Objective To observe the curative efficacy of chitin medical wound paste for incision healing of after circumcision. Methods A total of 120 patients received circumcision were randomly divided into 2 groups. The observation group was treated with Chitin medical wound paste after circumcision, and the control group was treated with conventional gauze wound dressing. Results Compared with control group, wound healing was markedly better in the observation group (P<0.05), and the incidence of postoperative complications decreased significantly (P<0.05). Conclusion Application of chitin medical wound paste after circumcision is safe and effective, which has a good promotion of incision healing, prevention of edema and infection and incision scar. Therefore it is worthy of clinical application.

  20. Identification of a Chitin-Induced Small RNA That Regulates Translation of the tfoX Gene, Encoding a Positive Regulator of Natural Competence in Vibrio cholerae▿†

    OpenAIRE

    Yamamoto, Shouji; Izumiya, Hidemasa; Mitobe, Jiro; Morita, Masatomo; Arakawa, Eiji; Ohnishi, Makoto; Watanabe, Haruo

    2011-01-01

    The tfoX (also called sxy) gene product is the central regulator of DNA uptake in the naturally competent bacteria Haemophilus influenzae and Vibrio cholerae. However, the mechanisms regulating tfoX gene expression in both organisms are poorly understood. Our previous studies revealed that in V. cholerae, chitin disaccharide (GlcNAc)2 is needed to activate the transcription and translation of V. cholerae tfoX (tfoXVC) to induce natural competence. In this study, we screened a multicopy librar...

  1. 甲壳素/壳聚糖及其衍生物的最新应用进展%The Latest Research Progress in Use of Chitin/Chitosan and their Derivates

    Institute of Scientific and Technical Information of China (English)

    董静

    2011-01-01

    甲壳素是存在于自然界中的唯一带阳离子的糖类聚合物,来源于节肢动物和低等植物的真菌和藻类.前者大量存在于海洋之中,以虾蟹为主,能够被生物降解,产量仅次于纤维素.甲壳素脱乙酰化的产物称为壳聚糖,壳聚糖经结构修饰后可得到一系列适合不同需要的性能优良的衍生物.甲壳素、壳聚糖及其衍生物特殊的结构特征不仅决定其具有良好的物理、化学、机械性能,还具有很好的生物相容性、降解性、免疫抗原性小、无毒性等特殊的生物医学特性.同时具有良好的生物安全性,使其在医药保健、农业、食品工业、水处理、纺织、化工、化妆品等领域均有广泛的应用.%Chitin is the only cationic carbohydrate polymer existing in the nature, deriving from arthropods ,fungi, and algae. The former source is mainly abundant in ocean, especially in shrimps and crabs ,which can be biologically degraded, only second to cellulose in production. Chitosan,a deacetylated product of chitin,can synthesize a series of derivatives with excellent properties for different needs through the structural modification. The structures of chitin, chitosan, and its derivatives not only render themselves good physical,chemical, and mechanical properties, but also favorable biocompatibility, biodegradability, minimal imnmnogenicity,and non-toxicity. Additionally, they also have good biosafety profiles. Therefore, they have a widerange application in healthcare, agriculture, food industry, water treatment, textiles, chemicals, cosmetics and other fields.

  2. Structure and Performance of Two Water-Soluble Chitin and SF Composite Membrane%两种水溶性甲壳素和丝素共混膜的结构与性能

    Institute of Scientific and Technical Information of China (English)

    张敏; 许小玲; 孟晓荣

    2012-01-01

    制备了两种水溶性甲壳素:N-乙酰化壳聚糖(N-ACTS,DS=0.55)和6-O-羟乙基甲壳素(6-O-GC,DS=1.0),将其分别与丝素(SF)混合,制备了水溶性均相混合的复合膜;红外光谱(FT-IR)证明了均相混合的复合膜中两种天然高分子官能团结构的变化,相互之间形成了氢键结合,成为均一的混合体,表明天然高分子之间具有良好的相容性;原子间力显微镜(AFM)表面形貌观察表明:均相混合复合膜的表面比单一丝素蛋白质和多糖螺旋立体构造分布均匀表面光滑;体外细胞培养实验表明:人皮肤纤维芽细胞在两种复合膜上均生长良好,具有良好的生物相容性和医学应用前景.%Water-soluble homogeneous mixed composite membranes were prepared by mixing two water-soluble chitin, nitrogen acylation chitosan (N-ACTS,DS =0.55) and 6-0-hydroxyethyl chitin (6-0-GC,DS = 1.0) respectively with silk fibroin (SF).The fourier transform infrared spectroscopy (FT-IR) demonstrated that the functional group structure on two kinds of natural polymer were changed, formed the hydrogen bond combination and a homogeneous mixture, indicated that the two kinds of natural polymer had good compatibility. The surface morphology of composite films were observed by the atomic force microscope ( AFM) , the results showed that the surface of the homogeneous mixed composite films were more uniform distributed and glossy than pure SF protein and polysaccharose spiral three-dimensional structure, people skin fiber buds cells on the two kinds of mixture membranes were nice in vitro cell culture experiment, indicated that N-ACTS/SF and 6-0-GC/SF composite films had good biocompatibility and medical application prospect.

  3. Proteolytic digestive enzymes and peritrophic membranes during the development of Plodia interpunctella (Lepidoptera: Piralidae): targets for the action of soybean trypsin inhibitor (SBTI) and chitin-binding vicilin (EvV).

    Science.gov (United States)

    Amorim, Ticiana M L; Macedo, Leonardo L P; Uchoa, Adriana F; Oliveira, Adeliana S; Pitanga, Joelma C M; Macedo, Francisco P; Santos, Elizeu A; de Sales, Mauricio P

    2008-09-10

    The digestive system of P. interpunctella was characterized during its larval development to determine possible targets for the action of proteinaceous enzyme inhibitors and chitin-binding proteins. High proteolytic activities using azocasein at pH 9.5 as substrate were found. These specific enzymatic activities (AU/mg protein) showed an increase in the homogenate of third instar larvae, and when analyzed by individual larvae (AU/gut), the increase was in sixth instar larvae. Zymograms showed two bands corresponding to those enzymatic activities, which were inhibited by TLCK and SBTI, indicating that the larvae mainly used serine proteinases at pH 9.5 in their digestive process. The presence of a peritrophic membrane in the larvae was confirmed by chemical testing and light microscopy. In a bioassay, P. interpunctella was not susceptible to the soybean trypsin inhibitor, which did not affect larval mass and mortality, likely due to the weak association with its target digestive enzyme. EvV (Erythrina velutina vicilin), when added to the diet, affected mortality (LD50 0.23%) and larval mass (ED50 0.27%). This effect was associated with EvV-binding to the peritrophic membrane, as seen by immunolocalization. EvV was susceptible to gut enzymes and after the digestion process, released an immunoreactive fragment that was bound to the peritrophic matrix, which probably was responsible for the action of EvV.

  4. A study on the maximal nerve defect length bridgeable by a chitin conduit%甲壳质套管桥接周围神经长度极限的研究

    Institute of Scientific and Technical Information of China (English)

    张丞; 王艳华; 张培训; 姜保国

    2010-01-01

    Objective To investigate the maximal defect length of a peripheral nerve that can be effectively bridged by a chitin conduit by repairing rat sciatic nerve gaps of various lengths with a chitin tube. Methods The right sciatic nerve of 24 SPF-class healthy adult male SD rats was transected at 5 mm proximal to the bifurcation. A segment of nerve was removed to leave a gap of 2, 5, 8 and 10 mm in length according to group assignment. The gap was bridged by a chitin conduit. Eight weeks after the surgery, the nerve distal to the tube was harvested and stained with osmic acid to acquire number of myelinated nerve fibers, axon area and myelin sheath thickness. Wet weight of the gastrocnemius muscles was obtained as well. Results In the 2 mm gap group 80% nerve fibers had regenerated into the distal nerve stump 8 weeks postoperatively. This regeneration was significantly better than those in the other gap groups( P < 0.01). The longer the gap, the worse the regeneration. The percentage of nerve fibers that regenerated into the distal nerve stump was 60% for the 5 mm gap, 20% for the 8 mm gap, and 1% for the 10 mm gap. Each was significantly better than next size up in nerve defect. Conclusion When chitin conduits are used to bridge a rat sciatic nerve defect, the optimal length of the gap for nerve regeneration is around 2 mm. The longest bridgeable defect that allows functional recovery is 5 mm. Nerve regeneration is seriously affected when the gap is longer than 10 mm.%目的 通过采用不同间隙套接修复大鼠坐骨神经损伤的实验研究,探讨甲壳质套管桥接修复周围神经损伤的长度极限.方法 SPF级健康成年雄性SD大鼠24只,于大鼠右侧坐骨神经分叉处以上5 mm建立坐骨神经离断伤模型,部分切除坐骨神经后使用甲壳质套管桥接修复,使神经断端间留有2、5、8和10 mm间隙.8周后常规锇酸染色,镜下观察套管远端有髓神经纤维数目、轴突平均面积、髓鞘平均厚

  5. Sum-Up of Productive Technology of Deacetylated Chitin-Coated Endoplasm Slow-Release Fertilizers%壳聚糖包膜内质缓释肥料生产技术总结

    Institute of Scientific and Technical Information of China (English)

    徐文峰; 黄滨

    2012-01-01

    壳聚糖包膜内质缓释肥料是一种由内质型缓释肥与包膜型控释肥技术相结合而成的新型缓释肥料,以控制肥料养分释放、流失和挥发为切入点,工艺技术简单,易于嫁接现有肥料生产工艺.介绍了壳聚糖包膜内质缓释肥料的研发背景、生产工艺、形成机理、技术创新点、产品质量标准、产品特点.针对壳聚糖包膜内质缓释肥料尚存在的一些问题,提出今后进一步研究与应用的方向.%The deacetylated chitin-coated endoplasm slow-release fertilizer is a new type of slow-release fertilizer made by a combination of technologies for endoplasm slow-release fertilizers and coated control-release fertilizers, with the control of fertilizer nutrient release, loss and volatilization as the cut-in point, the process is simple and easily grafted to available fertilizer productive technology. A description is given of the research and development of the fertilizer, its production technology, formation mechanism, technological innovation, product quality standard, and product characteristics, In the light of some problems that still remain, the direction tor further research and application is proposed.

  6. Study on cultivate yeasty by using recuperated protein from industrial process chitin sewage as fermentation nitrogen source%甲壳素加工废水回收蛋白作发酵氮源的实验研究

    Institute of Scientific and Technical Information of China (English)

    钱俊青; 魏敏; 匡春兰

    2013-01-01

    甲壳素加工废水回收蛋白作酒精发酵氮源实验是以活性干酵母为菌种制备种子液发酵,首先确定了以酵母浸膏为氮源的最佳发酵工艺条件为m(碳源):m(氮源)=4.5:1.甲壳素加工废水中回收的蛋白经丙酮萃取色素后,得蛋白干粉进行酒精发酵试验,酒精产率较低,故采用对甲壳素回收蛋白酸解再用于酒精发酵.结果表明:经酸解的回收蛋白是一种优良的氮源,用于酒精发酵效果与商品氮源相一致.%Using the recuperated protein from industrial process chitin sewage as alcoholic fermentation nitrogen source has been studied. Make active dried yeasts as the strain for seed liquid fermentation, the optimal fermentation condition is: m (carbon) : m (nitrogen) = 4. 5 : 1. After extracting pigment by acetone from recycling protein, protein powder was obtained for alcohol fermentation. The test showed that the production rate of alcohol is low; so the recuperated protein degraded by acid was obtained. The result turns out that the recuperated protein can be degraded by acid into an excellent nitrogen source, which can be used for the alcoholic fermentation just like the commercial nitrogen.

  7. Surface exploration of a room-temperature ionic liquid-chitin composite film decorated with electrochemically deposited PdFeNi trimetallic alloy nanoparticles by pattern recognition: an elegant approach to developing a novel biotin biosensor.

    Science.gov (United States)

    Gholivand, Mohammad-Bagher; Jalalvand, Ali R; Goicoechea, Hector C; Paimard, Giti; Skov, Thomas

    2015-01-01

    In this study, a novel biosensing system for the determination of biotin (BTN) based on electrodeposition of palladium-iron-nickel (PdFeNi) trimetallic alloy nanoparticles (NPs) onto a glassy carbon electrode (GCE) modified with a room-temperature ionic liquid (RTIL)-chitin (Ch) composite film (PdFeNi/ChRTIL/GCE) is established. NPs have a wide range of applications in science and technology and their sizes are often measured using transmission electron microscopy (TEM) or X-ray diffraction. Here, we used a pattern recognition method (digital image processing, DIP) for measuring particle size distributions (PSDs) from scanning electron microscopic (SEM) images in the presence of an uneven background. Different depositions were performed by varying the number of cyclic potential scans (N) during electroreduction step. It was observed that the physicochemical properties of the deposits were correlated to the performance of the PdFeNi/ChRTIL/GCE with respect to BTN assay. The best results were obtained for eight electrodeposition cyclic scans, where small-sized particles (19.54 ± 6.27 nm) with high density (682 particles µm(-2)) were obtained. Under optimized conditions, a linear range from 2.0 to 44.0 × 10(-9) mol L(-1) and a limit of detection (LOD) of 0.6 × 10(-9) mol L(-1) were obtained. The PdFeNi/ChRTIL nanocomposite showed excellent compatibility, enhanced electron transfer kinetics, large electroactive surface area, and was highly sensitive, selective, and stable toward BTN determination. Finally, the PdFeNi/ChRTIL/GCE was satisfactorily applied to the determination of BTN in infant milk powder, liver, and egg yolk samples.

  8. 培养条件对嗜热芽孢杆菌HU1合成几丁质降解酶及脱乙酰基酶的影响%Effects of Culture Conditions on the Synthesis of Chitinase and Chitin Deacetylase from Thermophilic Bacillus sp. HU1

    Institute of Scientific and Technical Information of China (English)

    戴德慧; 胡伟莲; 李巍

    2011-01-01

    [ Objective ] The aims were to investigate the effects of culture conditions on the enzyme production by Thermophilic Bacillus sp.Hul and provide basis for fermentation of enzyme and preparation of chitosan oligosaccharide. [ Method] The shake flask culture was employed to research the culture conditions of Thermophilic Bacillus sp. for producing Chitinase and Chitin Deacetylase HU1. [ Result] The optimum carbon source was powder chitinase with the optimum addition of 3.5%; while yeast power was the optimum nitrogen source with the optimal addition of 1.0%. It was beneficial to synthesize chitinase and chitin deacetylase when the original pH was 6.0. In addition, the synthesis of chitinase and chitin deacetylaso was inhibited by Cu2+ , and activated by Ca2+. However, Mg2+ and Zn2+ did not show significant inhibitory effects on the synthesis of the two enzymes. Moreover, the production of chitinaso and chitin deacetylase reached peak after culture for 72 h.The hydrolysate components of the crude enzyme solution were analyzed by using powder chitin as substrate, and the result suggested that chitosan oligosaccharide with the molecular weight of less than hexaose was the main component. [ Conclusion ] The preparation process of chitosan oligosaccharide of small molecules by using crude enzyme solution was simple, which could provided a basis for the further developments of health care production, biological pesticide, animal feed additive and food additive.%[目的]研究培养条件对嗜热芽孢杆菌HU1产酶的影响,为工业化发酵生产酶及壳寡糖的制备提供依据.[方法]采用摇瓶培养方式,对嗜热芽孢杆菌HU1产几丁质降解酶及脱乙酰基酶的培养条件进行研究.[结果]最佳诱导碳源为粉末几丁质,其最适添加量为3.5%;最佳氮源为酵母粉,最适添加量为1.0%;初始pH值为6.0时,有利于产酶;Cu2+对酶的合成表现出明显的抑制作用;而Ca2+则能有效增加产酶能力.Mg2+及Zn2+

  9. 氟防龋材料、改性几丁质生物胶治疗口腔幽门螺杆菌感染的疗效观察%Observation of Efficacy of Fluorine Methods Material and Modified Chitin Xanthan Gum in Treatment of Oral Helicobacter Pylori Infection

    Institute of Scientific and Technical Information of China (English)

    王彬; 吴婷; 李小园; 张凤云; 王靖

    2015-01-01

    OBJECTIVE:To evaluate into the treatment effect and efficacy observation of Fluorine methods material and Modified chitin xanthan gum in treatment of patients with oral helicobacter pylori (Hp) infection.METHODS:618 cases of positive oral Hp infection patients without gastrointestinal symptoms were divided into observation group and control group via random number table .310 cases in the observation group received non-drug treatment of toothpaste combined with Fluorine methods material for brushing test; among which 86 cases with oral cavity ulcer additionally received Modified chitin xanthan gum modification of chitin biological glue spray on oral ulcer .308 cases in the control group , among which 79 cases with oral cavity ulcer , by setting blank control in toothpaste , toothpaste was used to clean the mouth after the daily dinner.The Hp positive rate, average Hp eradication time and indicators such as oral cavity ulcer healing condition in two groups were compared .RESULTS: In the treatment of after 30 d, 90 d, observation group also significantly lower than control group in patients with positive detection rate , the difference was statistically significant ( P <0.05 );After the treatment of 90d, the positive rate in the observation group was 92.11%(280/304), significantly higher than that in the control group [3.90%(12/304)], with statistically significant difference (P<0.05);In the observation group of patients with oral Hp an average time and oral ulcer eradication effect a radical cure cases were significantly better than the control group, the differences were statistically significant (P<0.05).CONCLUSIONS: Fluorine methods material and Modified chitin xanthan gum can effectively remove the oral Hp infection , which has economical and convenient operation , and good compliance.It is worthy of popularization and application .%目的:探讨氟防龋材料、改性几丁质生物胶对口腔幽门螺杆菌(helicobacter pylori,Hp)

  10. 中华稻蝗几丁质脱乙酰基酶2基因的分子特性和生物学功能%Molecular Characterization and Functional Analysis of Chitin Deacetylase 2 Gene in Oxya chinensis

    Institute of Scientific and Technical Information of China (English)

    于荣荣; 丁国伟; 郭亚平; 马恩波; 张建珍

    2014-01-01

    Objective] In order to provide a theoretical basis for selecting novel target for pest control, molecular characteristics and biological function of chitin deacetylase 2 gene (OcCDA2) from Oxya chinensis were studied.[Method]The cDNA sequences of OcCDA2 were searched from transcriptome of O. chinensis by bioinformatics method, and the conserved domain was anaylzed, the homologous sequences from Tribolium castaneum, Drosophila melanogaster; Anopheles gambiae, Bombyx mori and Choristoneura fumiferana were selected to construct phylogenetic tree. The real-time PCR was applied to detect the relative expression of OcCDA2 in different tissues and developmental stages of the 5th instar nymphs. The RNA interference (RNAi) was performed to study the biological function of the OcCDA2 during molting and development of O. chinensis. [Result]The full length cDNA sequences of two chitin deacetylase genes were identified. The amino acid analysis showed that they possessed the signal peptide, the open reading frame contained three conserved domains: chitin binding domain (ChBD), low-density lipoprotein receptor chass A domain (LDLa) and chitin deacetylase catalytic domain (CDA). The phylogenetic analysis showed that two variants of OcCDA2 clustered with the CDA2s of five insect species, and the two variants differed only in one exon consisting of about 120 nucleotides, the alternatively spliced regions gathered with CDA2a or CDA2b, respectively. Based on sequence alignment and phylogenetic analysis, two variants of OcCDA2 were named as OcCDA2a and OcCDA2b. Tissue-specific expression analysis indicated that both OcCDA2a and OcCDA2b were mainly expressed in the integument, foregut and hindgut. Developmental expression patterns showed that the relative expressions of OcCDA2a and OcCDA2b were higher in the 1st day of 5th instar nymphs, then decreased gradually, and began to ascend before molting. RNAi results showed that the expression of target genes was significantly reduced in 24

  11. 甲壳素神经再生室注入聚乳酸-聚乙醇酸-重组人促红细胞生成素微球促进缺损周围神经的修复%Injection of polylactic acid-polyglycolic acid-recombinant human erythropoietin microspheres into chitin nerve regeneration chamber can promote sciatic nerve regeneration

    Institute of Scientific and Technical Information of China (English)

    黄亚洲; 陈清汉; 任明明

    2012-01-01

    背景:促红细胞生成素除了具有造血的作用以外,对神经系统损伤的修复也起着重要作用.目的:观察聚乳酸-聚乙醇酸-重组人促红细胞生成素微球对大鼠坐骨神经再生的作用.方法:雌性SD大鼠60只,随机分为3组.制备大鼠双侧坐骨神经缺损模型(1 cm缺损)以及可吸收甲壳素神经再生室.实验组室内注入聚乳酸-聚乙醇酸-重组人促红细胞生成素微球;对照组室内注入聚乳酸-聚乙醇酸微球;空白对照组室内注入等渗生理盐水.结果与结论:实验组再生神经的传导速度优于对照组及空白对照组,且12周优于6周,差异有显著性意义(P < 0.05).S-100 免疫组织化学及Loyez氏神经染色法显示:实验组神经纤维数量多于对照组及空白对照组,12周多于6周,差异有显著性意义(P < 0.05).结果提示聚乳酸-聚乙醇酸-重组人促红细胞生成素微球能够促进实验性坐骨神经缺损的再生和功能的恢复.%BACKGROUND: Erythropoietin (EPO) plays an important role in hematopoiesis as well as in the repair of nervous system injury. OBJECTIVE: To observe the effect of polylactic acid-polyglycolic acid-recombinant human erythropoietin microspheres on sciatic nerve regeneration. METHODS: Sixty female SD rats were randomly divided into three groups, 20 rats in each group. The bilateral sciatic nerve defect model was prepared (1 cm defect) and the absorbable chitin nerve regeneration chamber was prepared. The chambers of the rats in the experimental group were injected with polylactic acid-polyglycolic acid-recombinant human erythropoietin microspheres, chambers of the rats in the control group were injected with polylactic acid-polyglycolic acid microspheres and chambers of the rats in the blank control group were injected with normal saline in the same dose. RESULTS AND CONCLUSION: The conduction velocity of the regeneration nerve in the experimental group was better than that in the control group and

  12. Effect of deletion of chitin synthase genes on mycelial morphology and culture viscosity in Aspergillus oryzae

    DEFF Research Database (Denmark)

    Müller, Christian; Hansen, K.; Szabo, Peter;

    2003-01-01

    .4-22.5 g kg(-1) biomass) and the power-law model adequately described the rheological properties. In the cultivations there were pellets, clumps, and freely dispersed hyphal elements. The different morphological fractions were quantified using image analysis. The apparent viscosity of the fermentation...... broth was significantly affected by the biomass concentration, the morphology, and also by pH. The chsB disruption strain had lower consistency index K values for all biomass concentrations investigated, which is a desirable trait for industrial Aspergillus fermentations. (C) 2003 Wiley Periodicals, Inc....

  13. Biosorption Of Heavy Metals From Mining Influenced Water Onto Chitin Products

    Science.gov (United States)

    Mining influenced water (MIW) emanating from mine sites poses a major environmental concern due to its impact on water contamination caused by low pH and the presence of high concentrations of toxic metals. Chitorem SC-20® (raw crushed crab shells containing 40% w/w C...

  14. Knickkopf protein protects and organizes chitin in the newly synthesized insect exoskeleton

    Science.gov (United States)

    New cuticle synthesis and molting are complex developmental processes that all insects must undergo to allow for growth. However, little is known about how insects regulate the selective degradation of the old cuticle while leaving the new one intact. In this study we show that in the red flour beet...

  15. Stability of spray-dried chitosan salts derived from lobster chitin as a raw material

    Directory of Open Access Journals (Sweden)

    Nilia De la Paz

    2015-12-01

    Full Text Available Aim: The objective of this work was to develop and validate a method for determining the degree of molar deacetylation of chitosan acetate and chitosan lactate, as well as to study the stability of both salts. Materials and Methods: A spectrophotometric method was validated according to internationally-established quantitative techniques. Three industrial batches of chitosan acetate and chitosan lactate, obtained by spray drying, were stored under shelf life conditions for twelve months. Organoleptic characteristics, the degree of molar deacetylation, pH, loss on drying and microbiological count were determined at the beginning and end of the study. Results and Discussion: The statistical data proved that the two methods complied with international standards for the validation of analytical techniques. It was shown that the procedures developed were linear, specific, precise and accurate, so they can be used for the purposes of quality control and stability study of the polymer salts. Salts remained in powder form, with a light-yellow to dark-yellow coloration. Values of loss on drying (2.5 - 5.2 % of chitosan salt using acetic or lactic acid, as a solvent, indicated the good quality of spray-dried particles of chitosan. Similar behavior was obtained regarding pH. The two salts stayed within the parameters that determine their quality, both in the initial stage and after twelve months at room temperature. Conclusion: Spray drying chitosan acetate and chitosan lactate, stored at room temperature in a dry place, in double polyethylene bags and multilayer paper bags, kept their physical, chemical and microbiological characteristics for a period of twelve months.

  16. Direct conversion of chitin biomass to 5-hydroxymethylfurfural in concentrated ZnCl2 aqueous solution

    DEFF Research Database (Denmark)

    Wang, Yingxiong; Pedersen, Christian Marcus; Deng, Tiansheng;

    2013-01-01

    of the reaction parameters including the screening of 8 co-catalysts was carried out. Among them, AlCl3 and B(OH)3 improved 5-HMF yield, whereas CdCl2, CuCl2 and NH4Cl had no effect. CrCl3, SnCl4 and SnCl2 showed negative effects, i.e. lower yields. Consequently, the optimal reaction conditions were found...

  17. Melanin Externalization in Candida albicans Depends on Cell Wall Chitin Structures▿

    OpenAIRE

    Walker, Claire A; Gómez, Beatriz L.; Mora-Montes, Héctor M.; Mackenzie, Kevin S; Munro, Carol A.; Brown, Alistair J. P.; Gow, Neil A. R.; Kibbler, Christopher C.; Odds, Frank C.

    2010-01-01

    The fungal pathogen Candida albicans produces dark-pigmented melanin after 3 to 4 days of incubation in medium containing l-3,4-dihydroxyphenylalanine (l-DOPA) as a substrate. Expression profiling of C. albicans revealed very few genes significantly up- or downregulated by growth in l-DOPA. We were unable to determine a possible role for melanin in the virulence of C. albicans. However, we showed that melanin was externalized from the fungal cells in the form of electron-dense melanosomes tha...

  18. Dried Fruit of the Luffa Sponge as a Source of Chitin for Applications as Skin Substitutes

    Directory of Open Access Journals (Sweden)

    Ping-Lun Jiang

    2014-01-01

    Full Text Available LUFFACHITIN obtained from the residue of the sponge-like dried fruit of Luffa aegyptiaca was developed as a weavable skin substitute in this study. A chemical analysis revealed that LUFFACHITIN was composed of a copolymer containing N-acetyl-glucosamine (~40% as a major monomer with a filamentary structure as demonstrated by both optical and scanning electron microscopy. The pulp-like white residue of the sponge-like dried fruit of Luffa aegyptiaca after treatment was then woven into a thin, porous membrane by filtration and lyophilization as a skin substitute for conducting wound-healing study on rats. The results indicated that the LUFFACHITIN membrane showed significant wound-healing enhancement (25 days to complete healing compared to cotton gauze (>30 days, but not inferior to that of SACCHACHITIN. Furthermore, the LUFFACHITIN membrane had advantages of having a high yield, better physical properties for fabrication, and a more attractive appearance.

  19. Dried fruit of the Luffa sponge as a source of chitin for applications as skin substitutes.

    Science.gov (United States)

    Jiang, Ping-Lun; Chien, Mei-Yin; Sheu, Ming-Thau; Huang, Yi-You; Chen, Meng-Hsun; Su, Ching-Hua; Liu, Der-Zen

    2014-01-01

    LUFFACHITIN obtained from the residue of the sponge-like dried fruit of Luffa aegyptiaca was developed as a weavable skin substitute in this study. A chemical analysis revealed that LUFFACHITIN was composed of a copolymer containing N-acetyl-glucosamine (~40%) as a major monomer with a filamentary structure as demonstrated by both optical and scanning electron microscopy. The pulp-like white residue of the sponge-like dried fruit of Luffa aegyptiaca after treatment was then woven into a thin, porous membrane by filtration and lyophilization as a skin substitute for conducting wound-healing study on rats. The results indicated that the LUFFACHITIN membrane showed significant wound-healing enhancement (25 days to complete healing) compared to cotton gauze (>30 days), but not inferior to that of SACCHACHITIN. Furthermore, the LUFFACHITIN membrane had advantages of having a high yield, better physical properties for fabrication, and a more attractive appearance. PMID:24812618

  20. Dried Fruit of the Luffa Sponge as a Source of Chitin for Applications as Skin Substitutes

    OpenAIRE

    Ping-Lun Jiang; Mei-Yin Chien; Ming-Thau Sheu; Yi-You Huang; Meng-Hsun Chen; Ching-Hua Su; Der-Zen Liu

    2014-01-01

    LUFFACHITIN obtained from the residue of the sponge-like dried fruit of Luffa aegyptiaca was developed as a weavable skin substitute in this study. A chemical analysis revealed that LUFFACHITIN was composed of a copolymer containing N-acetyl-glucosamine (~40%) as a major monomer with a filamentary structure as demonstrated by both optical and scanning electron microscopy. The pulp-like white residue of the sponge-like dried fruit of Luffa aegyptiaca after treatment was...

  1. MECHANISMS OF HEAVY METAL REMOVAL FROM ACID MINE DRAINAGE USING CHITIN

    Science.gov (United States)

    Acid Mine Drainage (AMD) emanating from inactive or active mine sites contains elevated levels of toxic heavy metals, which can have an adverse impact to the surrounding environment. The major pathway involved in generation of AMD is weathering of pyritic mineral ores, where in s...

  2. Effect of acid Lugol solution as preservative on two representative chitineous and gelatinous zooplankton groups

    DEFF Research Database (Denmark)

    Jaspers, Cornelia; Carstensen, Jacob

    2009-01-01

    -iodide and iodine (Lugol solution) as preservative on body sizes of different mesozooplankton groups have not been investigated. We tested the effect of 2% acidified Lugol solution on body sizes over time on two major marine mesozooplankton groups, namely larvaceans and copepods, which are representatives...

  3. Some physiological aspects of the insecticidal action of diflubenzuron, an inhibitor of chitin synthesis

    NARCIS (Netherlands)

    Grosscurt, A.C.

    1980-01-01

    Diflubenzuron is the common name for 1-(4-chlorophenyl)-3-(2,6-difluorobenzoyl)urea, the active ingredient of the insecticide Dimilin.Diflubenzuron was discovered in 1971 as a larvicide. Evidence was provided by several authors that the larvicidal effect of this compound was caused by its interferen

  4. Effect of the chitin synthesis inhibitor triflumuron on the development, viability and reproduction of Aedes aegypti

    OpenAIRE

    Thiago Affonso Belinato; Ademir Jesus Martins; José Bento Pereira Lima; Tamara Nunes Lima-Camara; Alexandre Afrânio Peixoto; Denise Valle

    2009-01-01

    The control of Aedes aegypti is impaired due to the development of resistance to chemical insecticides. Insect Growth Regulators (IGR) exhibit distinct mechanisms of action and are considered potential vector control alternatives. Studies regarding the effects of sublethal IGR doses on the viability of resulting adults will contribute to eval-uating their impact in the field. We analyzed several aspects of Ae. aegypti adults surviving exposure to a partially lethal dose of triflumuron, a chit...

  5. Novel In Vivo-Degradable Cellulose-Chitin Copolymer from Metabolically Engineered Gluconacetobacter xylinus▿ †

    OpenAIRE

    Yadav, Vikas; Paniliatis, Bruce J.; Shi, Hai; Lee, Kyongbum; Cebe, Peggy; Kaplan, David L.

    2010-01-01

    Despite excellent biocompatibility and mechanical properties, the poor in vitro and in vivo degradability of cellulose has limited its biomedical and biomass conversion applications. To address this issue, we report a metabolic engineering-based approach to the rational redesign of cellular metabolites to introduce N-acetylglucosamine (GlcNAc) residues into cellulosic biopolymers during de novo synthesis from Gluconacetobacter xylinus. The cellulose produced from these engineered cells (modif...

  6. The Syntaxin Tlg1p Mediates Trafficking of Chitin Synthase III to Polarized Growth Sites in Yeast

    OpenAIRE

    Holthuis, Joost C.M.; Nichols, Benjamin J.; Pelham, Hugh R.B.

    1998-01-01

    Tlg1p and Tlg2p, members of the syntaxin family of SNAREs in yeast, have been implicated in both endocytosis and the retention of late Golgi markers. We have investigated the functions of these and the other endocytic syntaxins Pep12p and Vam3p. Remarkably, growth is possible in the absence of all four proteins. In the absence of the others, Pep12p and Tlg1p can each create endosomes accessible to the endocytic tracer dye FM4-64. However, although Pep12p is require...

  7. Degradation of chitin and chitosan by a recombinant chitinase derived from a virulent Aeromonas hydrophila isolated from diseased channel catfish

    Science.gov (United States)

    A chitinase was identified in extracellular products of a virulent Aeromonas hydrophila isolated from diseased channel catfish (Ictalurus punctatus). Bioactive recombinant chitinase (rChi-Ah) was produced in Escherichia coli. Purified rChi-Ah had optimal activity at temperature of 42°C and pH 6.5. T...

  8. Potential role of chitinases and chitin-binding proteins in host-microbial interactions during the development of intestinal inflammation

    OpenAIRE

    Tran, Hoa T.; Barnich, Nicolas; Mizoguchi, Emiko

    2011-01-01

    The small and large intestines contain an abundance of luminal antigens derived from food products and enteric microorganisms. The function of intestinal epithelial cells is tightly regulated by several factors produced by enteric bacteria and the epithelial cells themselves. Epithelial cells actively participate in regulating the homeostasis of intestine, and failure of this function leads to abnormal and host-microbial interactions resulting in the development of intestinal inflammation. Ma...

  9. Progress in antimicrobial activities of chitin, chitosan and its oligosaccharides: a systematic study needs for food applications.

    Science.gov (United States)

    Dutta, J; Tripathi, S; Dutta, P K

    2012-02-01

    In recent years, active biomolecules such as chitosan and its derivatives are undergoing a significant and very fast development in food application area. Due to recent outbreaks of contaminations associated with food products, there have been growing concerns regarding the negative environmental impact of packaging materials of antimicrobial biofilms, which have been studied. Chitosan has a great potential for a wide range of applications due to its biodegradability, biocompatibility, antimicrobial activity, nontoxicity and versatile chemical and physical properties. It can be formed into fibers, films, gels, sponges, beads or nanoparticles. Chitosan films have been used as a packaging material for the quality preservation of a variety of foods. Chitosan has high antimicrobial activities against a wide variety of pathogenic and spoilage microorganisms, including fungi, and Gram-positive and Gram-negative bacteria. A tremendous effort has been made over the past decade to develop and test films with antimicrobial properties to improve food safety and shelf-life. This review highlights the preparation, mechanism, antimicrobial activity, optimization of biocide properties of chitosan films and applications including biocatalysts for the improvement of quality and shelf-life of foods.

  10. USER Friendly Cloning Coupled with Chitin-Based Natural Transformation Enables Rapid Mutagenesis of Vibrio vulnificus▿ †

    OpenAIRE

    Paul A. Gulig; Tucker, Matthew S.; Thiaville, Patrick C.; Joseph, Jennifer L.; Brown, Roslyn N.

    2009-01-01

    Vibrio vulnificus is a bacterial contaminant of shellfish and causes highly lethal sepsis and destructive wound infections. A definitive identification of virulence factors using the molecular version of Koch's postulates has been hindered because of difficulties in performing molecular genetic analysis of this opportunistic pathogen. For example, conjugation is required to introduce plasmid DNA, and allelic exchange suicide vectors that rely on sucrose sensitivity for counterselection are no...

  11. Studi Karakterisasi Pembuatan Kitin Dan Kitosan Dari Cangkang Belangkas (Tachypleus Gigas) Untuk Penentuan Berat Molekul

    OpenAIRE

    Noviary, Harry

    2011-01-01

    Research of the characterization study of the manufacture and modification of chitin and chitosan from crab shells (tachipleus gigas) for molecular weight determination. Chitin is modified to obtain phases that produce chitin crab I and II. Cshitin crab I used to produce chitosan crab I, so did the king crab chitin II is used to produce chitosan crab II. Characterization of chitin and chitosan involves determining the water content, ash content, total nitrogen, protein content, elemental anal...

  12. Identification of Albizia lebbeck seed coat chitin-binding vicilins (7S globulins) with high toxicity to the larvae of the bruchid Callosobruchus maculatus

    Energy Technology Data Exchange (ETDEWEB)

    Souza, A.J. [Laboratório de Química e Função de Proteínas e Peptídeos, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, RJ (Brazil); Ferreira, A.T.S.; Perales, J.; Beghini, D.G. [Laboratório de Toxinologia, Departamento de Fisiologia e Farmacodinâmica, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, RJ (Brazil); Fernandes, K.V.S.; Xavier-Filho, J.; Venancio, T.M.; Oliveira, A.E.A. [Laboratório de Química e Função de Proteínas e Peptídeos, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, RJ (Brazil)

    2011-01-27

    Seed coat is a specialized maternal tissue that interfaces the embryo and the external environment during embryogenesis, dormancy and germination. In addition, it is the first defensive barrier against penetration by pathogens and herbivores. Here we show that Albizia lebbeck seed coat dramatically compromises the oviposition, eclosion and development of the bruchid Callosobruchus maculatus. Dietary supplementation of bruchid larvae with A. lebbeck seed coat flour causes severe weight loss and reduces survival. By means of protein purification, mass spectrometry and bioinformatic analyses, we show that chitinbinding vicilins are the main source of A. lebbeck tegumental toxicity to C. maculatus. At concentrations as low as 0.1%, A. lebbeck vicilins reduce larval mass from 8.1 ± 1.7 (mass of control larvae) to 1.8 ± 0.5 mg, which corresponds to a decrease of 78%. Seed coat toxicity constitutes an efficient defense mechanism, hindering insect predation and preventing embryo damage. We hypothesize that A. lebbeck vicilins are good candidates for the genetic transformation of crop legumes to enhance resistance to bruchid predation.

  13. 甲壳素与甲壳胺纤维2.纤维的性能%Chitin and Chitosan Fibers 2.Fiber Properties

    Institute of Scientific and Technical Information of China (English)

    秦益民

    2004-01-01

    甲壳素和甲壳胺纤维具有纤维材料的强度、柔软性、高表面积和形成各种类型的织物的能力,又有这两种天然高分子所特有的生物相容性、生物可降解性、广谱抗菌性、凝血作用以及促进伤口复愈、调节血脂、降低胆固醇、增强免疫和抗肿瘤等多种生理活性作用.

  14. Chitin and Chitosan Fibers I.The Preparation of Fibers%甲壳素与甲壳胺纤维1.纤维的制备

    Institute of Scientific and Technical Information of China (English)

    秦益民

    2004-01-01

    甲壳素和甲壳胺是广泛存在于动物和植物中的天然高分子材料.近年来,这两个高分子的生物相容性、生物可降解性、对伤口愈合的促进性能和其它一些优异性能在科技和工商界引起了产泛的重视.作为一种天然再生资源,它们在许多领域内都有很广的应用和开发潜力.总结了甲壳素和甲壳胺纤维的生产条件.

  15. 甲壳素及其衍生物纤维的研究进展%Preparation of Chitin, Chitosan and Their Derivatives Fibers

    Institute of Scientific and Technical Information of China (English)

    刘永乐; 刘兆峰; 吴清基

    2007-01-01

    回顾了用不同溶剂溶解甲壳素并纺制纤维的尝试,以及壳聚糖乙酸水溶液的纺丝工艺和通过后处理提高壳聚糖纤维强度的方法;对甲壳素和壳聚糖的化学改性和衍生物纤维的制备作了综述.

  16. Factors affecting quality of chitin and chitosan fibers%甲壳素和甲壳胺纤维质量的影响因素

    Institute of Scientific and Technical Information of China (English)

    刘呈坤; 马建伟

    2005-01-01

    概述了影响甲壳素和甲壳胺纤维质量的因素,如甲壳素和甲壳胺的品质、纺丝原液的溶剂选择及浓度的确定、凝固浴的确定;简述了通过化学改性来改善甲壳素和甲壳胺纤维性能;介绍了国内外为改善纤维质量所作的最新研究.

  17. Chitin and Chitosan Fibers 3.Chemical Modifications%甲壳素与甲壳胺纤维 3.纤维的化学改性

    Institute of Scientific and Technical Information of China (English)

    秦益民; 朱长俊

    2004-01-01

    作为天然高分子材料, 甲壳素和甲壳胺有许多优良的物化和生物活性.通过化学改性,甲壳素和甲壳胺可以获得更多的性能.总结了甲壳素和甲壳胺的化学衍生物和各种复合材料.

  18. Study on Extraction Technology of Cochineal Chitin%胭脂虫甲壳素的提取工艺研究

    Institute of Scientific and Technical Information of China (English)

    郑华; 张弘; 陈晓鸣

    2009-01-01

    本实验对胭脂虫(Dactylopius COCCUS Costa)色素加工剩余物进行甲壳素提取.结果表明,蛋白质脱除最适条件为NaOH浓度1.Omol/L,反应温度80℃,时间2h;无机盐脱除最适条件为盐酸浓度1.0mol/L,反应温度50℃,时间60min.

  19. Impact on bacterial community in midguts of the Asian corn borer larvae by transgenic Trichoderma strain overexpressing a heterologous chit42 gene with chitin-binding domain.

    Science.gov (United States)

    Li, Yingying; Fu, Kehe; Gao, Shigang; Wu, Qiong; Fan, Lili; Li, Yaqian; Chen, Jie

    2013-01-01

    This paper is the first report of the impact on the bacterial community in the midgut of the Asian corn borer (Ostrinia furnacalis) by the chitinase from the transgenic Trichoderma strain. In this study, we detected a change of the bacterial community in the midgut of the fourth instar larvae by using a culture-independent method. Results suggested that Proteobacteria and Firmicutes were the most highly represented phyla, being present in all the midgut bacterial communities. The observed species richness was simple, ranging from four to five of all the 16S rRNA clone libraries. When using Trichoderma fermentation liquids as additives, the percentages of the dominant flora in the total bacterial community in larval midgut changed significantly. The community of the genus Ochrobactrum in the midgut decreased significantly when the larvae were fed with the fermentation liquids of the transgenic Trichoderma strain Mc4. However, the Enterococcus community increased and then occupied the vacated niche of the Ochrobactrum members. Furthermore, the Shannon-Wiener (H) and the Simpson (1-D) indexes of the larval midgut bacterial library treated by feeding fermentation liquids of the transgenic Trichoderma strain Mc4 was the lowest compared with the culture medium, fermentation liquids of the wild type strain T30, and the sterile artificial diet. The Enterococcus sp. strain was isolated and characterized from the healthy larvae midgut of the Asian corn borer. An infection study of the Asian corn borer larvae using Enterococcus sp. ACB-1 revealed that a correlation existed between the increased Enterococcus community in the larval midgut and larval mortality. These results demonstrated that the transgenic Trichoderma strain could affect the composition of the midgut bacterial community. The change of the midgut bacterial community might be viewed as one of the factors resulting in the increased mortality of the Asian corn borer larvae.

  20. Changes of exoskeleton surface roughness and expression of crucial participation genes for chitin formation and digestion in the mud crab (Macrophthalmus japonicus) following the antifouling biocide irgarol.

    Science.gov (United States)

    Park, Kiyun; Nikapitiya, Chamilani; Kim, Won-Seok; Kwak, Tae-Soo; Kwak, Ihn-Sil

    2016-10-01

    Irgarol is a common antifoulant present in coastal sediment. The mud crab Macrophthalmus japonicus is one of the most abundant of the macrobenthos in the costal environment, and its exoskeleton has a protective function against various environmental threats. We evaluated the effects of irgarol toxicity on the exoskeleton of M. japonicus, which is the outer layer facing the environment. We analyzed transcriptional expression of exoskeleton, molting, and proteolysis-related genes in the gill and hepatopancreas of these exposed M. japonicus. In addition, changes in survival and exoskeleton surface characteristics were investigated. In the hepatopancreas, mRNA expression of chitinase 1 (Mj-chi1), chitinase 4 (Mj-chi4), and chitinase 5 (Mj-chi5) increased in M. japonicus exposed to all concentrations of irgarol. Mj-chi1 and Mj-chi4 expressions from 1 to 10μgL(-1) were dose- and time-dependent. Ecdysteroid receptor (Mj-EcR), trypsin (Mj-Tryp), and serine proteinase (Mj-SP) in the hepatopancreas were upregulated in response to different exposure levels of irgarol at day 1, 4, or 7. In contrast, gill Mj-chi5, Mj-Tryp, and Mj-SP exhibited late upregulated responses to 10μgL(-1) irgarol compared to the control at day 7. Mj-chi1 showed early upregulation upon exposure to 10μgL(-1) irgarol and Mj-chi4 showed no changes in transcription in the gill. Gill Mj-EcR presented generally downregulated expression patterns. In addition, decreased survival and change of exoskeleton surface roughness were observed in M. japonicus exposed to the three concentrations of irgarol. These results suggest that exposure to irgarol induces changes in the exoskeleton, molting, and proteolysis metabolism of M. japonicus. PMID:27318560

  1. Extraction of chitin and preparation of chitosan in freshwater crabs Sinopotamon yangtsekiense%华溪蟹几丁质的提取与壳聚糖的制备

    Institute of Scientific and Technical Information of China (English)

    王金香; 王兰

    2005-01-01

    2003年8~12月,以华溪蟹蟹壳为主要原料,采用稀盐酸脱钙、稀碱脱蛋白和浓碱脱乙酰方法并经正交试验,得到不同粘度、不同脱乙酰度的天然高分子化合物--几丁质和壳聚糖产品.结果表明,制备高粘度可溶性壳聚糖的最佳工艺条件是:用9%的酸处理蟹壳至无气泡为止,水洗至中性,再经8%NaOH 70℃处理1h脱色得到几丁质产品;所得几丁质经50%NaOH 95℃处理3h,水洗,干燥,得到粘度为1125mPa·s的高分子量壳聚糖产品.经测定,几丁质在蟹壳中含量为13%左右,壳聚糖收率为8%~9%.

  2. Impact on bacterial community in midguts of the Asian corn borer larvae by transgenic Trichoderma strain overexpressing a heterologous chit42 gene with chitin-binding domain.

    Directory of Open Access Journals (Sweden)

    Yingying Li

    Full Text Available This paper is the first report of the impact on the bacterial community in the midgut of the Asian corn borer (Ostrinia furnacalis by the chitinase from the transgenic Trichoderma strain. In this study, we detected a change of the bacterial community in the midgut of the fourth instar larvae by using a culture-independent method. Results suggested that Proteobacteria and Firmicutes were the most highly represented phyla, being present in all the midgut bacterial communities. The observed species richness was simple, ranging from four to five of all the 16S rRNA clone libraries. When using Trichoderma fermentation liquids as additives, the percentages of the dominant flora in the total bacterial community in larval midgut changed significantly. The community of the genus Ochrobactrum in the midgut decreased significantly when the larvae were fed with the fermentation liquids of the transgenic Trichoderma strain Mc4. However, the Enterococcus community increased and then occupied the vacated niche of the Ochrobactrum members. Furthermore, the Shannon-Wiener (H and the Simpson (1-D indexes of the larval midgut bacterial library treated by feeding fermentation liquids of the transgenic Trichoderma strain Mc4 was the lowest compared with the culture medium, fermentation liquids of the wild type strain T30, and the sterile artificial diet. The Enterococcus sp. strain was isolated and characterized from the healthy larvae midgut of the Asian corn borer. An infection study of the Asian corn borer larvae using Enterococcus sp. ACB-1 revealed that a correlation existed between the increased Enterococcus community in the larval midgut and larval mortality. These results demonstrated that the transgenic Trichoderma strain could affect the composition of the midgut bacterial community. The change of the midgut bacterial community might be viewed as one of the factors resulting in the increased mortality of the Asian corn borer larvae.

  3. 用丰年虫卵壳制备甲壳素和壳聚糖%Producing chitin and chitosan from the eggs shell of brine shrimp

    Institute of Scientific and Technical Information of China (English)

    孙文敏; 李铮; 李久红

    2008-01-01

    介绍了用丰年虫卵壳制备甲壳素及壳聚糖的方法及过程,通过傅立叶变换红外光谱仪的检测并与美国标准谱图库检索出的用蟹壳制备的壳聚糖光谱图对照,证实丰年虫卵壳制备的壳聚糖.

  4. [Effectiveness of 2,6-dihalogenbenzoyl urea derivatives as potential inhibitors of chitin biosynthesis regarding the house fly Musca domestica L. and cockroach Blatella germanica L].

    Science.gov (United States)

    Styczyńska, B; Krzemińska, A; Sobótka, W; Balicki, R

    1989-01-01

    The biological activity was determined of 20 compounds from the group of asymmetrically substituted urea derivatives. They were derivatives of 1-(hetero)-aryl-3(2,6-dichlorobenzoyl)urea, compounds in Table 1, (1-12) which represented three groups of compounds: a) monochlorine or trifluoromethyl derivatives of benzene, b) monomethyl-substituted 2-pyridine derivatives, c) a derivative of 5-bromo-3-pyridine, and symmetrical derivates (Table 2 compounds 1-8) 2.2; 3.3; 4.4 groupings: a) N-(2,6-dichlorobenzoyl)urea derivatives, and b) N-(2-chloro-6-fluorobenzoyl)urea derivatives. The experiment was carried out on larvae and adult forms of M. domestica L. and Blatella germanica L. The tested substances were administered in food to the insects. Of the tested compounds complete inhibition of the development of flies was caused by the compound designated with the symbol AG 6. Compounds AG 13, AG 15 and AG 17 given to larvae inhibited the development of the insects by 33 to 100% acting mainly in later phases of the development (pupation). Compound AG 5 was found to be a very strong inhibitor of the development of cockroaches acting on larvae and adult females Of 800 tested larvae exposed to concentrations 0.001 to 1% none reached the adult phase. The exposed adult females formed cocoons but no larvae hatched from them.

  5. Application of Chitinous Materials in Production and Purification of a Poly(l-lactic acid) Depolymerase from Pseudomonas tamsuii TKU015

    OpenAIRE

    Tzu-Wen Liang; Shan-Ni Jen; Anh Dzung Nguyen; San-Lang Wang

    2016-01-01

    The management of fishery residues and plastics is considered to be a vital strategy for conserving resources and maintaining the quality of the environment. Poly(l-lactic acid) (PLA) is a commercially promising, renewable, and biodegradable plastic. In this study, a PLA depolymerase was produced in a squid pen powder (SPP) and recycled plastic waste (PLA powder)-containing medium by Pseudomonas tamsuii TKU015, a bacterial strain isolated from Taiwanese soil. This PLA depolymerase had a molec...

  6. Application of Chitinous Materials in Production and Purification of a Poly(l-lactic acid Depolymerase from Pseudomonas tamsuii TKU015

    Directory of Open Access Journals (Sweden)

    Tzu-Wen Liang

    2016-03-01

    Full Text Available The management of fishery residues and plastics is considered to be a vital strategy for conserving resources and maintaining the quality of the environment. Poly(l-lactic acid (PLA is a commercially promising, renewable, and biodegradable plastic. In this study, a PLA depolymerase was produced in a squid pen powder (SPP and recycled plastic waste (PLA powder-containing medium by Pseudomonas tamsuii TKU015, a bacterial strain isolated from Taiwanese soil. This PLA depolymerase had a molecular weight of 58 kDa and was purified to homogeneity from the supernatant of a TKU015 culture. The optimum pH of TKU015 PLA depolymerase is 10, and the optimal temperature of the enzyme is 60 °C. In addition to PLA, TKU015 PLA depolymerase degraded fibrinogen and tributyrin, but did not hydrolyze casein, triolein, and poly(β-hydroxybutyrate. Taken together, these data demonstrate that P. tamsuii TKU015 produces a PLA depolymerase to utilize SPP and polylactide as carbon/nitrogen sources.

  7. Yeast Interacting Proteins Database: YPR106W, YBR038W [Yeast Interacting Proteins Database

    Lifescience Database Archive (English)

    Full Text Available as prey (0) YBR038W CHS2 Chitin synthase II, requires activation from zymogenic form in order to catalyze th...ption Chitin synthase II, requires activation from zymogenic form in order to cat

  8. Gclust Server: 113022 [Gclust Server

    Lifescience Database Archive (English)

    Full Text Available 113022 SCE_YBR038W=CHS2 Cluster Sequences - 963 Chitin synthase II, requires activa...ative annotation Chitin synthase II, requires activation from zymogenic form in order to catalyze the transf

  9. Chitooligosaccharide and Its Derivatives: Preparation and Biological Applications

    Directory of Open Access Journals (Sweden)

    Gaurav Lodhi

    2014-01-01

    Full Text Available Chitin is a natural polysaccharide of major importance. This biopolymer is synthesized by an enormous number of living organisms; considering the amount of chitin produced annually in the world, it is the most abundant polymer after cellulose. The most important derivative of chitin is chitosan, obtained by partial deacetylation of chitin under alkaline conditions or by enzymatic hydrolysis. Chitin and chitosan are known to have important functional activities but poor solubility makes them difficult to use in food and biomedicinal applications. Chitooligosaccharides (COS are the degraded products of chitosan or chitin prepared by enzymatic or chemical hydrolysis of chitosan. The greater solubility and low viscosity of COS have attracted the interest of many researchers to utilize COS and their derivatives for various biomedical applications. In light of the recent interest in the biomedical applications of chitin, chitosan, and their derivatives, this review focuses on the preparation and biological activities of chitin, chitosan, COS, and their derivatives.

  10. 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.

  11. NCBI nr-aa BLAST: CBRC-PMAR-01-0383 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-PMAR-01-0383 ref|NP_001034492.1| chitin synthase 2 [Tribolium castaneum] gb|AA...Q55061.1| chitin synthase CHS2 [Tribolium castaneum] gb|AAQ62692.1| chitin synthase [Tribolium castaneum] NP_001034492.1 0.021 22% ...

  12. NCBI nr-aa BLAST: CBRC-PMAR-01-0127 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-PMAR-01-0127 ref|NP_001034492.1| chitin synthase 2 [Tribolium castaneum] gb|AA...Q55061.1| chitin synthase CHS2 [Tribolium castaneum] gb|AAQ62692.1| chitin synthase [Tribolium castaneum] NP_001034492.1 0.007 21% ...

  13. Anti-fungal properties of chitinolytic dune soil bacteria

    NARCIS (Netherlands)

    De Boer, W.; Klein Gunnewiek, P.J.A.; Lafeber, P.; Janse, J.H.; Spit, B.E.; Woldendorp, J.W.

    1998-01-01

    Anti-fungal properties of chitinolytic soil bacteria may enable them to compete successfully for chitin with fungi. Additionally, the production of chitinase may be part of a lytic system that enables the bacteria to use living hyphae rather than chitin as the actual growth substrate, since chitin i

  14. PREPARASI DAN KARAKTERISASI KITIN DARI KULIT UDANG PUTIH (Litophenaeus vannamei

    Directory of Open Access Journals (Sweden)

    Mardiyah Kurniasih

    2007-11-01

    Full Text Available Chitin is one of the most abundant natural polysaccharides produced by many living organisms; it is usually found as a component of crustacean shells. In this paper, Chitin have been isolated from white shrimp (Litophenaeus vannamei. The preparation of chitin using chemical products to deproteinize and demineralize the source material. Characterization included determination of water, ash, fat and protein degree; moreover chitin powder characterize with FTIR and XRD spectroscopy. The result showed that process efficiency of chitin from white shrimp (Litophenaeus vannamei was 20.95%, with degree of water, ash, fat and protein were 5.39, 2.66, 1.54 and 36.16%, respectively.

  15. The Research of Abstracting Chitin Used Artificial Raising Maggot and Pupa of Musca Domestica%人工饲养家蝇蛆和蛹提取几丁质的研究

    Institute of Scientific and Technical Information of China (English)

    苏水莲; 李娟; 胡雅琼; 谢学斌; 廖华

    2002-01-01

    目的:提取蝇蛆表皮和蛹壳的几丁质.方法:在实验室内人工饲养家蝇48天,传代饲养3代,用人工竹筛分离收集蝇蛆和蛹,并用清洗、脱钙、脱脂、漂白、脱乙酰基、干燥的方法初步提取了几丁质.结果:获得蝇蛆表皮几丁质0.8g和蛹壳几丁质2g.结论:用人工饲养家蝇所得到的家蝇蛆表皮和蛹壳的几丁质含量分别为60%~70%.

  16. Progress in the research on Chitin and Chitosan as Natural Biopolymer%甲壳素和壳聚糖作为天然生物高分子材料的研究进展

    Institute of Scientific and Technical Information of China (English)

    车小琼; 孙庆申; 赵凯

    2008-01-01

    甲壳素是自然界中含量仅次于纤维素的天然高分子,壳聚糖是甲壳素脱乙酰化后带有阳离子的多糖.壳聚糖中的自由氨基以及它的高结晶性,使得它能溶于酸,而不溶于碱和绝大数的有机溶剂.同时壳聚糖具有无毒性、无刺激性、良好的生物相容性、生物可溶解性, 以及高的电荷密度,因而被作为一种新型的天然生物材料得到广泛应用.文章介绍了甲壳素和壳聚糖的结构和性质,综述分析了甲壳素和壳聚糖在制备微球和作为支架材料中的应用, 并总结了甲壳素和壳聚糖在这两个方面存在的问题和发展前景.

  17. Offering opening experiment on the preparation of chitin and chitosan from shells of shrimp and crab%利用虾蟹壳制备甲壳素和壳聚糖实验研究

    Institute of Scientific and Technical Information of China (English)

    李增新; 王国明; 孙治中

    2009-01-01

    以蟹、虾的外壳为原料、采用酸浸-碱解法和浓碱水解法分别制备出黏度高、色泽洁白的甲壳素和壳聚糖产品.对制备过程中酸碱的浓度、反应温度和时间、配料比以及氧化还原的条件等对产品质量和收率的影响进行了探讨.实验涉及原料的前处理、溶解、搅拌、除杂、脱色、烘干、焙烧以及产品的酸碱滴定、杂质检测等多种基本操作步骤和分析检测手段,适合列为化学专业开放性实验.

  18. Enzymatic properties of chitinase-producing antagonistic bacterium Paenibacillus chitinolyticus with various substrates.

    Science.gov (United States)

    Song, Yong-Su; Seo, Dong-Jun; Ju, Wan-Taek; Lee, Yong-Seong; Jung, Woo-Jin

    2015-12-01

    Various chitin substrates were used to investigate the properties of enzymes produced from the chitinase-producing bacterium Paenibacillus chitinolyticus MP-306 against phytopathogens. The MP-306 bacterium was incubated in nine culture media [crab shell powder chitin (CRS), chitin-protein complex powder (CPC), carboxymethyl-chitin powder (CMC), yeast extract only (YE), LB (Trypton, NaCl, and yeast extract), GT (Trypton, NaCl, and glucose), crab shell colloidal chitin (CSC), squid pen powder chitin (SPC), and cicada slough powder chitin (CSP)] at 30 °C for 3 days. Chitinase isozymes in CPC medium were expressed strongly as CN1, CN2, CN3, CN4, CN5, and CN6 bands on native-PAGE gels. Chitinase isozymes in CPC and CMC medium were expressed as 13 bands (CS1-CS13) on SDS-PAGE gels. Chitinase isozymes were expressed strongly on SDS-PAGE gels as two bands (CS6 and CS8) on YE and LB medium and 13 bands (CS1-CS13) on SPC medium. In crude enzyme, chitinase isozymes at pH 7 and pH 9 in chitin media appeared strongly on SDS-PAGE gels. Partial purified enzyme indicated high stability of enzyme activity at various temperatures and pHs in chitin medium, while these enzymes indicated low activity staining of enzyme on electrophoresis gels at various temperatures and pHs condition of chitin medium.

  19. Radiation induced formation of giant cells (Saccharomyces uvarum). Pt. 1

    International Nuclear Information System (INIS)

    X-irradiated yeast cells (Saccharomyces uvarum) grown in liquid media stop mitosis and form giant cells. Chitin ring formation, being a prerequisite for cell separation, was studied by fluorescence microscopy using Calcofluor White, a chitin specific dye. Experiments with inhibitors of DNA synthesis (hydroxyurea) and chitin synthesis (polyoxin D) demonstrate chitin ring formation to be dependent on DNA synthesis, whereas bud formation is independent of DNA synthesis and chitin ring formation respectively. Basing on these results the formation of X-ray induced giant cells implies one DNA replication which in turn induces the formation of only one chitin ring between mother cell and giant bud. Obviously no septum can be formed. Thus cell separation does not occur, but the bud already formed, produces another bud demonstrating that bud formation itself is independent of DNA synthesis. (orig.)

  20. 生分解性材料としてのキトサンフィルムの物性と抗菌活性

    OpenAIRE

    中島, 照夫

    2009-01-01

    [Synopsis] Chitin, chitosan and quaternary chitosan films were prepared, and the physical properties and the antibacterial activities of chitosan and quaternary chitosan films were evaluated. The tensile strength of chitin films was 30~40% lower than that of chitosan films, but the crystallinity of chitin film was much higher than that of chitosan films. The crystallinity and orientation of crystallites were hardly affected by the four kinds of solvent chosen to cast chitosan films, but a de...

  1. Compositions and methods for removal of toxic metals and radionuclides

    Science.gov (United States)

    Cuero, Raul G. (Inventor); McKay, David S. (Inventor)

    2007-01-01

    The present invention relates to compositions and methods for the removal of toxic metals or radionuclides from source materials. Toxic metals may be removed from source materials using a clay, such as attapulgite or highly cationic bentonite, and chitin or chitosan. Toxic metals may also be removed using volcanic ash alone or in combination with chitin or chitosan. Radionuclides may be removed using volcanic ash alone or in combination with chitin or chitosan.

  2. The Technology of Extracting from Waste Mycelia

    Institute of Scientific and Technical Information of China (English)

    ZHANG; Hong

    2001-01-01

    Chitin is one of the most abundant natural resources. chitosan is deacetylated from chitin. As natural organisms, chitosan is easier to be decomposed with organisms and eatable. So chitosan is wildly used in biology, medicine, foodstuff, cosmetics and so on[1,2] Chitin is a sort of natural glucosamine compound with wealthy resources, but a large amount of chitin is prepared from crab shell and crayfish shell. Some research works have carried on the preparation of chitosan from other resources, such as silkworm pupa, waste mycelia etc.[3,4]  ……

  3. The Technology of Extracting from Waste Mycelia

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hong; WANG YunPu; WANG RongMin

    2001-01-01

    @@ Chitin is one of the most abundant natural resources. chitosan is deacetylated from chitin. As natural organisms, chitosan is easier to be decomposed with organisms and eatable. So chitosan is wildly used in biology, medicine, foodstuff, cosmetics and so on[1,2] Chitin is a sort of natural glucosamine compound with wealthy resources, but a large amount of chitin is prepared from crab shell and crayfish shell. Some research works have carried on the preparation of chitosan from other resources, such as silkworm pupa, waste mycelia etc.[3,4

  4. Synthesis and Characterization of a Chitosan Derivative for Electro-Optical Applications

    Science.gov (United States)

    Prastofer, Thomas

    1996-01-01

    Chitin is a naturally occurring polymer of alpha(1-4) poly N-acetylglucosamine found primarily in the shells of crustaceans and insects. This polymer is chemically and thermally stable and physically durable as a consequence of hydrogen bonding which causes the alignment and ordering of the polymer chains into microcrystals which aggregate into sheets with chiral nematic order. Industry has attempted to take advantage of chitin's properties and low cost (chitin is a waste product of the shellfish industry) to produce durable fibers and other products. This has been largely unsuccessful because of chitin's non reactivity and insolubility. Chitosan is the deacetylation product of chitin and retains many of the structural properties of chitin. Unlike chitin, chitosan is soluble in aqueous solution at reduced pH making it easier to be processed into fibers and films than chitin. Chitosan and its derivatives are now used in such commercial applications as wound dressings, waste water treatment, and in pharmaceuticals. In this study, we have synthesized a chitosan derivative, N-para-nitrophenyl chitosan (NPNPC), as a model material with potential applications in electro optics.

  5. Functional analysis of LysM effectors secreted by fungal plant pathogens

    NARCIS (Netherlands)

    Kombrink, A.

    2014-01-01

      Chitin is a homopolymer of N-acetyl-d-glucosamine (GlcNAc)that is abundantly present in nature and found as a major structural component in the fungal cell wall. In Chapter 1,the role of chitin as an important factor in the interaction between fungal pathogens and their plan

  6. Functional analysis of the Arabidopsis thaliana AtEP3 endochitinase

    NARCIS (Netherlands)

    Passarinho, P.A.

    2001-01-01

    Chitinases are enzymes that are capable of catalyzing the hydrolysis of chitin, a homopolymer of N-acetylglucosamine. Chitin is the main constituent of the exoskeleton of insects, of crustacean shells and of the cell wall of many fungi but is absent in plants. This led to the commonly accepted hypot

  7. Bioproduction of chitooligosaccharides: present and perspectives.

    Science.gov (United States)

    Jung, Woo-Jin; Park, Ro-Dong

    2014-10-28

    Chitin and chitosan oligosaccharides (COS) have been traditionally obtained by chemical digestion with strong acids. In light of the difficulties associated with these traditional production processes, environmentally compatible and reproducible production alternatives are desirable. Unlike chemical digestion, biodegradation of chitin and chitosan by enzymes or microorganisms does not require the use of toxic chemicals or excessive amounts of wastewater. Enzyme preparations with chitinase, chitosanase, and lysozymeare primarily used to hydrolyze chitin and chitosan. Commercial preparations of cellulase, protease, lipase, and pepsin provide another opportunity for oligosaccharide production. In addition to their hydrolytic activities, the transglycosylation activity of chitinolytic enzymes might be exploited for the synthesis of desired chitin oligomers and their derivatives. Chitin deacetylase is also potentially useful for the preparation of oligosaccharides. Recently, direct production of oligosaccharides from chitin and crab shells by a combination of mechanochemical grinding and enzymatic hydrolysis has been reported. Together with these, other emerging technologies such as direct degradation of chitin from crustacean shells and microbial cell walls, enzymatic synthesis of COS from small building blocks, and protein engineering technology for chitin-related enzymes have been discussed as the most significant challenge for industrial application.

  8. Bioproduction of Chitooligosaccharides: Present and Perspectives

    Directory of Open Access Journals (Sweden)

    Woo-Jin Jung

    2014-10-01

    Full Text Available Chitin and chitosan oligosaccharides (COS have been traditionally obtained by chemical digestion with strong acids. In light of the difficulties associated with these traditional production processes, environmentally compatible and reproducible production alternatives are desirable. Unlike chemical digestion, biodegradation of chitin and chitosan by enzymes or microorganisms does not require the use of toxic chemicals or excessive amounts of wastewater. Enzyme preparations with chitinase, chitosanase, and lysozymeare primarily used to hydrolyze chitin and chitosan. Commercial preparations of cellulase, protease, lipase, and pepsin provide another opportunity for oligosaccharide production. In addition to their hydrolytic activities, the transglycosylation activity of chitinolytic enzymes might be exploited for the synthesis of desired chitin oligomers and their derivatives. Chitin deacetylase is also potentially useful for the preparation of oligosaccharides. Recently, direct production of oligosaccharides from chitin and crab shells by a combination of mechanochemical grinding and enzymatic hydrolysis has been reported. Together with these, other emerging technologies such as direct degradation of chitin from crustacean shells and microbial cell walls, enzymatic synthesis of COS from small building blocks, and protein engineering technology for chitin-related enzymes have been discussed as the most significant challenge for industrial application.

  9. Modelling gastric evacuation in gadoids feeding on crustaceans

    DEFF Research Database (Denmark)

    Andersen, Niels Gerner; Chabot, Denis; Couturier, C. S.

    2016-01-01

    ) and the evacuation rate of both stages decreased (by a half) with increasing level of the crustacean armament in terms of chitin and ash. A common, interspecific parameterization of the model within each of the categories krill, shrimp and crab can probably be used if the contents of chitin and ash are similar among...

  10. Phenotypic and Genomic Properties of

    NARCIS (Netherlands)

    Sorokin, D.Y.; Rakitin, A.L.; Gumerov, V.M.; Beletsky, A.V.; Sinninghe Damsté, J.S.; Mardanov, A.V.; Ravin, N.V.

    2016-01-01

    Anaerobic enrichment from sediments of hypersaline alkaline lakes in Wadi el Natrun(Egypt) with chitin resulted in the isolation of a fermentative haloalkaliphilic bacterium,strain ACht6-1, growing exclusively with insoluble chitin as the substrate in a sodiumcarbonate-based medium at pH 8.5–10.5 an

  11. Conferring Natural-Derived Porous Microspheres with Surface Multifunctionality through Facile Coordination-Enabled Self-Assembly Process.

    Science.gov (United States)

    Han, Pingping; Shi, Jiafu; Nie, Teng; Zhang, Shaohua; Wang, Xueyan; Yang, Pengfei; Wu, Hong; Jiang, Zhongyi

    2016-03-01

    In this study, multifunctional chitin microspheres are synthesized and utilized as a platform for multiple potential applications in enzyme immobilization, catalytic reduction and adsorption. Porous chitin microspheres with an average diameter of 111.5 μm and a porous architecture are fabricated through a thermally induced phase separation method. Then, the porous chitin microspheres are conferred with surface multifunctionality through facile coordination-enabled self-assembly of tannic acid (TA) and titanium (Ti(IV)) bis(ammonium lactate)dihydroxide (Ti-BALDH). The multipoint hydrogen bonds between TA and chitin microspheres confer the TA-Ti(IV) coating with high adhesion capability to adhere firmly to the surface of the chitin microspheres. In view of the biocompatibility, porosity and surface activity, the multifunctional chitin microspheres are used as carriers for enzyme immobilization. The enzyme-conjugated multifunctional porous microspheres exhibit high catalytic performance (102.8 U·mg(-1) yeast alcohol dehydrogenase). Besides, the multifunctional chitin microspheres also find potential applications in the catalytic reduction (e.g., reduction of silver ions to silver nanoparticles) and efficient adsorption of heavy metal ions (e.g., Pb(2+)) taking advantages of their porosity, reducing capability and chelation property. PMID:26963907

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

    Science.gov (United States)

    Wang, Xilong; Xing, Baoshan

    2007-05-15

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

  13. Clone, Expression and CDA Activity of Chitin Deacetylase 1 from Hyphantria cunea (Drury)%美国白蛾几丁质脱乙酰酶1(HcCDA1)的克隆表达与酶活测定

    Institute of Scientific and Technical Information of China (English)

    闫晓平; 赵丹; 孙晓彤; 郭巍; 李少雅; 李景

    2015-01-01

    利用RACE-PCR方法,扩增得到编码美国白蛾Hyphantria cunea Drury几丁质脱乙酰酶基因HcCDA1.将该基因分别在大肠杆菌BL21和毕赤酵母细胞Pichia pastoris GS 115表达.经诱导表达后,Western blot分析表明HcCDA1在大肠杆菌中成功表达61.8 kD的蛋白,符合预期大小;在毕赤酵母GS115中成功表达80 kD蛋白.酶活性试验显示酵母细胞中表达的重组蛋白酶活力为1.685 U/mL.本研究利用毕赤酵母成功表达具有酶活力的重组HcCDA1蛋白,为进一步明确该蛋白的生理功能提供条件.

  14. INFLUENCE OF CHITIN AND CHEMICAL FUNGICIDES ON GROWTH AND ACTIVITY OF BIOCONTROL AGENTS AGAINST COTTON DISEASES%几丁质和杀菌剂对生物防治菌生长及其防治棉花病害效果的影响

    Institute of Scientific and Technical Information of China (English)

    杨合同; 唐文华; 王加宁; 徐砚珂; 肖斌

    2002-01-01

    研究了化学杀菌剂对木霉菌生长的影响,探讨了几丁质添加物对绿色木霉菌菌株LR、LTR-2、哈茨木霉菌菌株Q1、Q2和粉红粘帚霉菌菌株GLR防治棉花病害效果的影响.多菌灵、苯菌灵和甲基硫菌灵在1.66μg/ml时可以完全抑制Q1和Q2的生长,但在2.68μg/ml时才能完全抑制LR和LTR-2的生长.几丁质添加物使LTR-2和Q1防治棉花立枯病的效果完全丧失,但是能使LR从没有防治效果提高到防治效果为34.6%,而对粉红粘帚霉菌的防治效果没有显著影响;对于防治棉花黄萎病来说,几丁质添加物使木霉菌LR、LTR-2和GLR的防治效果降低,但是提高了Q1的防治效果;对于防治棉花枯萎病来说,几丁质添加物能提高所有测定菌株的防治效果.说明不同的生物防治菌株、添加物和病害组合对于获得良好的防治效果是重要的.

  15. Etude de la rémanence du triflumuron, inhibiteur de la synthèse de la chitine, selon la nature du tissu à l'égard de la mouche tsé-tsé Glossina palpalis gambiensis, dans une perspective de lutte autocide

    OpenAIRE

    Dabiré, R.; Ouédraogo, PA.; Bancé, AZ.

    2006-01-01

    Study of Remanence of Triflumuron, Synthesis Inhibitor, According to the Nature of Cloth with Regard to Tsetse Fly Glossina palpalis gambiensis in View of Self-killed Fight. The objective of this study is to assess the persistence of triflumuron impregated at a dosis of 9,7 g.m-2 on blue cotton, polyester and polypropylene material in comparison with the reference material made of 67% polyester and 33% cotton used in the control of tsetse fly. Impregnated materials were exposed to field condi...

  16. Etude de la rémanence du triflumuron, inhibiteur de la synthèse de la chitine, selon la nature du tissu à l'égard de la mouche tsé-tsé Glossina palpalis gambiensis, dans une perspective de lutte autocide

    Directory of Open Access Journals (Sweden)

    Dabiré, R.

    2006-01-01

    Full Text Available Study of Remanence of Triflumuron, Synthesis Inhibitor, According to the Nature of Cloth with Regard to Tsetse Fly Glossina palpalis gambiensis in View of Self-killed Fight. The objective of this study is to assess the persistence of triflumuron impregated at a dosis of 9,7 g.m-2 on blue cotton, polyester and polypropylene material in comparison with the reference material made of 67% polyester and 33% cotton used in the control of tsetse fly. Impregnated materials were exposed to field conditions during six months. One sample of each material was monthly taken and tsetse flies were exposed to it to assess the effects on the reproduction parameters of contaminated flies. Two types of contamination were evaluated: 20 days old females were contaminated by exposure to impregnated tissues while teneral females (3 days old were contaminated through the mating with males contaminated like the old females. Measured parameters were: the abortions, the pupa production, the non viable pupa and the hatching. The results from the old females showed that impregnated polypropylene material significantly reduced the average of hatching rate during six months (1 1.4% in comparison with impregnated reference material (15.14 21%, cotton material (14 25% and polyester one (21.5 34.3%. For young females the same tendencies were observed. During the six months period of investigation, triflumuron persistence was better on the polypropylene material than on the reference material for the control of tsetse flies by self sterilisation.

  17. Use of Low-cost Adsorbents to Chlorophenols and Organic Matter Removal of Petrochemical Wastewater

    Directory of Open Access Journals (Sweden)

    Aretha Moreira de Oliveira

    2013-11-01

    Full Text Available The removal of 2,4 diclorophenol (2,4-DCF and 2,4,6 trichlorophenol (2,4,6 TCF present in  petrochemical wastewater was evaluated using low-cost adsorbents, such as chitin, chitosan and coconut shells. Batch studies showed that the absorption efficiency for 2,4 DCF and 2,4,6 TCF follow the order: chitosan > chitin > coconut shells. Langmuir and Freundlich models have been applied to experimental isotherms data, to better understand the adsorption mechanisms. Petrochemical wastewater treatment with fixed bed column system using chitinous adsorbents showed a removal of COD (75% , TOG (90% and turbidity (74-89%.

  18. Study on the character of chitinase produced by Trichoderna spp.with measuring reducing sugar

    Institute of Scientific and Technical Information of China (English)

    LIU Kai-qi; XIANG Mei-mei; LIU Ren; ZENG Yong-san; LI Hua; JIANG Xin-yin; ZHANG Yue-li

    2004-01-01

    @@ A trusty and intuitionistic method for screening chitinase produced by Trichoderma spp. was developed. 38 isolates of Trichoderma spp. were cultured in liquid medium with chitin or colloidal chitin as the sole carbon source for 4 days. The supernatant of the fermented broth was mixed with colloidal chitin and heated in water-bath at 37℃ for 30 min, then 3,5-dinitrosalicylic acid reagent (DNS) was added to the mixture, and let them react for 10 min in water-bath. According to the different colour of the mixture, the isolates of Trichoderma spp. which can produce chitinase could be screened.

  19. Marine Vibrionaceae as a source of bioactive natural products

    DEFF Research Database (Denmark)

    Månsson, Maria; Wietz, Matthias; Gram, Lone;

    that some strains were capable of producing antibacterial compounds when grown on natural substrates such as chitin or seaweed. One Vibrio coralliilyticus strain was capable of producing the antibacterial compound when using chitin as the sole carbon source and in a live chitin model system, suggesting...... an ecological function. Using chemical profiling, vibrio strains were compared on a global scale, revealing that the production of certain compounds is a conserved feature independent of sample locations. Chemical screening techniques such as explorative solid-phase extraction led to the isolation of two novel...

  20. A simple fibril and lectin model for cyst walls of Entamoeba and perhaps Giardia.

    Science.gov (United States)

    Samuelson, John; Robbins, Phillips

    2011-01-01

    Cyst walls of Entamoeba and Giardia protect them from environmental insults, stomach acids, and intestinal proteases. Each cyst wall contains a sugar homopolymer: chitin in Entamoeba and a unique N-acetylgalactosamine (GalNAc) homopolymer in Giardia. Entamoeba cyst wall proteins include Jacob lectins (carbohydrate-binding proteins) that crosslink chitin, chitinases that degrade chitin, and Jessie lectins that make walls impermeable. Giardia cyst wall proteins are also lectins that bind fibrils of the GalNAc homopolymer. Although many of the details remain to be determined for the cyst wall of Giardia, current data suggest a relatively simple fibril and lectin model for the Entamoeba cyst wall.

  1. AcEST: BP918354 [AcEST

    Lifescience Database Archive (English)

    Full Text Available ein OS=Rattus norvegicus ... 34 0.43 sp|Q06703|CDA2_YEAST Chitin deacetylase 2 OS=Saccharomyces cerev... 33 ...B5VNK8_YEAS6 YLR308Wp-like protein OS=Saccharomyces ce... 33 7.4 tr|B3RHI7|B3RHI7_YEAS1 Chitin deacetylase OS=Saccharomyces cerev...... 33 7.4 tr|A7A1J3|A7A1J3_YEAS7 Chitin deacetylase OS=Saccharomyces cerev.

  2. Chitinases: An update

    Directory of Open Access Journals (Sweden)

    Rifat Hamid

    2013-01-01

    Full Text Available Chitin, the second most abundant polysaccharide in nature after cellulose, is found in the exoskeleton of insects, fungi, yeast, and algae, and in the internal structures of other vertebrates. Chitinases are enzymes that degrade chitin. Chitinases contribute to the generation of carbon and nitrogen in the ecosystem. Chitin and chitinolytic enzymes are gaining importance for their biotechnological applications, especially the chitinases exploited in agriculture fields to control pathogens. Chitinases have a use in human health care, especially in human diseases like asthma. Chitinases have wide-ranging applications including the preparation of pharmaceutically important chitooligosaccharides and N-acetyl D glucosamine, preparation of single-cell protein, isolation of protoplasts from fungi and yeast, control of pathogenic fungi, treatment of chitinous waste, mosquito control and morphogenesis, etc. In this review, the various types of chitinases and the chitinases found in different organisms such as bacteria, plants, fungi, and mammals are discussed.

  3. Use of slow-release fertilizers and biopolymers for stimulating hydrocarbon biodegradation in oil-contaminated beach sediments

    Energy Technology Data Exchange (ETDEWEB)

    Ran Xu; Li Ching Yong; Yong Giak Lim; Obbard, J.P. [National University of Singapore (Singapore). Department of Chemical and Biomolecular Engineering

    2005-07-01

    Nutrient concentration and hydrocarbon bioavailability are key factors affecting biodegradation rates of oil in contaminated beach sediments. The effect of a slow-release fertilizer, Osmocote, as well as two biopolymers, chitin and chitosan, on the bioremediation of oil-spiked beach sediments was investigated using an open irrigation system over a 56-day period under laboratory conditions. Osmocote was effective in sustaining a high level of nutrients in leached sediments, as well as elevated levels of microbial activity and rates of hydrocarbon biodegradation. Chitin was more biodegradable than chitosan and gradually released nitrogen into the sediment. The addition of chitin or chitosan to the Osmocote amended sediments enhanced biodegradation rates of the alkanes relative to the presence of Osmocote alone, where chitosan was more effective than chitin due to its greater oil sorption capacity. Furthermore, chitosan significantly enhanced the biodegradation rates of all target polycyclic aromatic hydrocarbons. (author)

  4. NUTRITIONAL VALUE OF THE FIELD CRICKET (GRYLLUS TESTACEUS WALKER)

    Institute of Scientific and Technical Information of China (English)

    DunWang; Yao-yuBai; Jiang-hongLi; Chuan-xiZhang

    2004-01-01

    The chemical composition and the nutritional quality of protein, fatty acids and chitin of adult field cricket Gryllus testaceus Walker were investigated. The adult insect contalned: crude protein 58.3 %; fat 10.3 %, chitin 8.7 % and ash 2.96 % on dry matter basis respectively. The essential amino acid profile compared well with FAO/WHO recommended pattern except for cysteine and methionine. The fatty acid analysis showed unsaturated acid of the field cricket to be present in high quantities, and the total percentage of oleic acid, linolic acid and linolenic acid was 77.51%. The chitin content of the insect was 8.7 % with a better quality than the commercial chitin that was prepared from shells of shrimp and crab. Therefore the chemical composition of the field cricket indicates the insect to be a good supplement to nutrition for food and feed, even a raw material for medicine.

  5. Chitosan functionalized poly(vinyl alcohol) for prospects biomedical and industrial applications: A review.

    Science.gov (United States)

    Rafique, Ammara; Mahmood Zia, Khalid; Zuber, Mohammad; Tabasum, Shazia; Rehman, Saima

    2016-06-01

    Chitin and chitosan are amino polysaccharides having multidimensional properties, such as biocompatibility, biodegradability, antibacterial properties and non-toxicity, muco-adhesivity, adsorption properties, etc., and thus they can be widely used in variety of areas. Although human history mainly relies on the biopolymers, however synthetic materials like polyvinyl alcohol (PVA) have good mechanical, chemical and physical properties. Functionalization of PVA with chitin and chitosan is considered very appropriate for the development of well-designed biomaterials such as biodegradable films, for membrane separation, for tissue engineering, for food packaging, for wound healing and dressing, hydro gels formation, gels formation, etc. Considering versatile properties of the chitin and chitosan, and wide industrial and biomedical applications of PVA, this review sheds a light on chitin and chitosan based PVA materials with their potential applications especially focusing the bio-medical field. All the technical scientific issues have been addressed highlighting the recent advancement. PMID:26893051

  6. Community structure of actively growing bacterial populations in plant pathogen suppressive soil

    NARCIS (Netherlands)

    Hjort, K.; Lembke, A.; Speksnijder, A.G.C.L.; Smalla, K.; Jansson, J.K.

    2007-01-01

    The bacterial community in soil was screened by using various molecular approaches for bacterial populations that were activated upon addition of different supplements. Plasmodiophora brassicae spores, chitin, sodium acetate, and cabbage plants were added to activate specific bacterial populations a

  7. Knickkopf and retroactive proteins are required for formation of laminar serosal procuticle during embryonic development of Tribolium castaneum.

    Science.gov (United States)

    Chaudhari, Sujata S; Noh, Mi Young; Moussian, Bernard; Specht, Charles A; Kramer, Karl J; Beeman, Richard W; Arakane, Yasuyuki; Muthukrishnan, Subbaratnam

    2015-05-01

    Chitin, a homopolymer of β-1-4-linked N-acetylglucosamine synthesized by chitin synthase A (Chs-A), is organized in the procuticle of the postembryonic cuticle or exoskeleton, which is composed of laminae stacked parallel to the cell surface to give stability and integrity to the underlying insect epidermal and other tissues. Our previous work has revealed an important role for two proteins from Tribolium castaneum named Knickkopf (TcKnk) and Retroactive (TcRtv) in postembryonic cuticular chitin maintenance. TcKnk and TcRtv were shown to be required for protection and organization of newly synthesized procuticular chitin. To study the functions of TcKnk and TcRtv in serosal and larval cuticles produced during embryogenesis in T. castaneum, dsRNAs specific for these two genes were injected into two week-old adult females. The effects of dsRNA treatment on ovarial integrity, oviposition, egg hatching and adult survival were determined. Insects treated with dsRNA for chitin synthase-A (TcChs-A) and tryptophan oxygenase (TcVer) were used as positive and negative controls for these experiments, respectively. Like TcChs-A RNAi, injection of dsRNA for TcKnk or TcRtv into adult females exhibited no adult lethality and oviposition was normal. However, a vast majority of the embryos did not hatch. The remaining (∼10%) of the embryos hatched into first instar larvae that died without molting to the second instar. Chitin content analysis following TcKnk and TcRtv parental RNAi revealed approximately 50% reduction in chitin content of eggs in comparison with control TcVer RNAi, whereas TcChs-A dsRNA-treatment led to >90% loss of chitin. Furthermore, transmission electron microscopic (TEM) analysis of serosal cuticle from TcChs-A, TcKnk and TcRtv dsRNA-treated insects revealed a complete absence of laminar organization of serosal (and larval) procuticle in comparison with TcVer dsRNA-treated controls, which exhibited normal laminar organization of procuticular chitin. The

  8. Doubly curved nanofiber-reinforced optically transparent composites

    Science.gov (United States)

    Shams, Md. Iftekhar; Yano, Hiroyuki

    2015-11-01

    Doubly curved nanofiber-reinforced optically transparent composites with low thermal expansion of 15 ppm/k are prepared by hot pressing vacuum-filtered Pickering emulsions of hydrophobic acrylic resin monomer, hydrophilic chitin nanofibers and water. The coalescence of acrylic monomer droplets in the emulsion is prevented by the chitin nanofibers network. This transparent composite has 3D shape moldability, making it attractive for optical precision parts.

  9. Chitosan in Plant Protection

    OpenAIRE

    Abdelbasset El Hadrami; Adam, Lorne R.; Ismail El Hadrami; Fouad Daayf

    2010-01-01

    Chitin and chitosan are naturally-occurring compounds that have potential in agriculture with regard to controlling plant diseases. These molecules were shown to display toxicity and inhibit fungal growth and development. They were reported to be active against viruses, bacteria and other pests. Fragments from chitin and chitosan are known to have eliciting activities leading to a variety of defense responses in host plants in response to microbial infections, including the accumulation of ph...

  10. Preparation and Characteristics of Chitosan Grafted byγ-methyl L-glutamate

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    1 IntroductionGraft polymers based on chitosan or chitin are considered to be useful as biocompatible materials, membrane materials, and supports for bioactive species as well as models for naturally occurring chitin, which has covalently linked polypeptide chains at some of the amino groups.In this paper, new solvent system was applied in graft copolymerization of γ-methyl L-glutamate NCA onto chitosan under heterogeneous conditions. The characteristics of the chitosan derivatives with side chains were stu...

  11. ISOLATION AND CHARACTERIZATION OF CHITINASE GENE FROM THE UNTRADITIONAL PLANT SPECIES

    OpenAIRE

    Dominika Ďurechová; Ildikó Matušíková; Jana Moravčíková; Martin Jopčík; Jana Libantová

    2013-01-01

    Round-leaf sundew (Drosera rotundifolia L.) from Droseraceae family belongs among a few plant species with strong antifungal potential. It was previously shown that chitinases of carnivorous plant species may play role during the insect prey digestion, when hard chitin skeleton is being decomposed. As many phytopathogenic fungi contain chitin in their cell wall our attention in this work was focused on isolation and in silico characterization of genomic DNA sequence of sundew chitinase gene. ...

  12. Tentacles of in vitro-grown round-leaf sundew (Drosera rotundifolia L.) show induction of chitinase activity upon mimicking the presence of prey

    OpenAIRE

    Matusikova, I.; Salaj, J.; Moravcikova, J.; Mlynarova, L.; Nap, J.P.H.; Libantova, J.

    2005-01-01

    Induction of plant-derived chitinases in the leaves of a carnivorous plant was demonstrated using aseptically grown round-leaf sundew (Drosera rotundifolia L.). The presence of insect prey was mimicked by placing the chemical inducers gelatine, salicylic acid and crustacean chitin on leaves. In addition, mechanical stirring of tentacles was performed. Chitinase activity was markedly increased in leaf exudates upon application of notably chitin. Application of gelatine increased the proteolyti...

  13. Vibrational spectroscopy for structural characterization of bioactive compounds

    Digital Repository Service at National Institute of Oceanography (India)

    Singh, K.S.; Majik, M.S.; Tilvi, S.

    ]. Chitin and chitosan 11    have shown various biological activities viz., analgesic, antitumor, hemostatic, hypocholesterolemic, antimicrobial, and antioxidant properties [29]. Chitin may be regarded as a cellulose derivative with an acetamido group... polysaccharides: Sulfated polysaccharides comprise a complex group of macromolecules with a wide range of critical biological activities including anticoagulant, antiviral, antitumor, anti-inflammatory and antioxidant [45-47]. Fucoidan a sulfated...

  14. Electron-beam distillation of natural polymers

    Science.gov (United States)

    Ponomarev, A. V.; Makarov, I. E.; Ershov, B. G.

    2014-01-01

    Pyrolysis of cellulose, lignin, and chitin may be upgraded by the use of an electron-beam irradiation. The radiation-thermal destruction mode does more probable production of liquid low-molecular-weight products instead of solid pyrolitic oligomers. Furans, methoxyphenols, and pyridines are dominant products of high-temperature radiolysis of cellulose, lignin, and chitin, respectively. The mechanism of chain destruction of natural polymers is considered.

  15. In vitro and in vivo application of RNA interference for targeting genes involved in peritrophic matrix synthesis in a lepidopteran system

    Institute of Scientific and Technical Information of China (English)

    Umut Toprak; Doug Baldwin; Martin Erlandson; Cedric Gillott; Stephanie Harris; Dwayne D.Hegedus

    2013-01-01

    The midgut of most insects is lined with a semipermeable acellular tube,the peritrophic matrix(PM),composed of chitin and proteins.Although various genes encoding PM proteins have been characterized,our understanding of their roles in PM structure and function is very limited.One promising approach for obtaining functional information is RNA interference,which has been used to reduce the levels of specific mRNAs using double-stranded RNAs administered to larvae by either injection or feeding.Although this method is well documented in dipterans and coleopterans,reports of its success in lepidopterans are varied.In the current study,the silencing midgut genes encoding PM proteins(insect intestinal mucin 1,insect intestinal mucin 4,PM protein l)and the chitin biosynthetic or modifying enzymes(chitin synthase-B and chitin deacetylase 1)in a noctuid lepidopteran,Mamestra configurata,was examined in vitro and in vivo.In vitro studies in primary midgut epithelial cell preparations revealed an acute and rapid silencing(by 24 h)for the gene encoding chitin deacetylase 1 and a slower rate of silencing(by 72 h)for the gene encoding PM protein 1.Genes encoding insect intestinal mucins were slightly silenced by 72 h,whereas no silencing was detected for the gene encoding chitin synthase-B.In vivo experiments focused on chitin deacetylase 1,as the gene was silenced to the greatest extent in vitro.Continuous feeding of neonates and fourth instar larvae with double-stranded RNA resulted in silencing of chitin deacetylase 1 by 24 and 36 h,respectively.Feeding a single dose to neonates also resulted in silencing by 24 h.The current study demonstrates that genes encoding PM proteins can be silenced and outlines conditions for RNA interference by per os feeding in lepidopterans.

  16. Chitinase expression in Listeria monocytogenes is positively regulated by the Agr system

    DEFF Research Database (Denmark)

    Paspaliari, Dafni Katerina; Mollerup, Maria Storm; Kallipolitis, Birgitte H.;

    2014-01-01

    The food-borne pathogen Listeria monocytogenes encodes two chitinases, ChiA and ChiB, which allow the bacterium to hydrolyze chitin, the second most abundant polysaccharide in nature. Intriguingly, despite the absence of chitin in human and mammalian hosts, both of the chitinases have been deemed....... Our results highlight a previously unrecognized role of the agr system and suggest that autoinducer-based regulation of chitinolytic systems may be more commonplace than previously thought....

  17. The gene for stinging nettle lectin (Urtica dioica agglutinin) encodes both a lectin and a chitinase.

    Science.gov (United States)

    Lerner, D R; Raikhel, N V

    1992-06-01

    Chitin-binding proteins are present in a wide range of plant species, including both monocots and dicots, even though these plants contain no chitin. To investigate the relationship between in vitro antifungal and insecticidal activities of chitin-binding proteins and their unknown endogenous functions, the stinging nettle lectin (Urtica dioica agglutinin, UDA) cDNA was cloned using a synthetic gene as the probe. The nettle lectin cDNA clone contained an open reading frame encoding 374 amino acids. Analysis of the deduced amino acid sequence revealed a 21-amino acid putative signal sequence and the 86 amino acids encoding the two chitin-binding domains of nettle lectin. These domains were fused to a 19-amino acid "spacer" domain and a 244-amino acid carboxyl extension with partial identity to a chitinase catalytic domain. The authenticity of the cDNA clone was confirmed by deduced amino acid sequence identity with sequence data obtained from tryptic digests, RNA gel blot, and polymerase chain reaction analyses. RNA gel blot analysis also showed the nettle lectin message was present primarily in rhizomes and inflorescence (with immature seeds) but not in leaves or stems. Chitinase enzymatic activity was found when the chitinase-like domain alone or the chitinase-like domain with the chitin-binding domains were expressed in Escherichia coli. This is the first example of a chitin-binding protein with both a duplication of the 43-amino acid chitin-binding domain and a fusion of the chitin-binding domains to a structurally unrelated domain, the chitinase domain. PMID:1375935

  18. DNA interaction, antitumor and antimicrobial activities of three-dimensional chitosan ring produced from the body segments of a diplopod.

    Science.gov (United States)

    Kaya, Murat; Akyuz, Bahar; Bulut, Esra; Sargin, Idris; Tan, Gamze; Erdonmez, Demet; Maheta, Mansi; Satkauskas, Saulius; Mickevičius, Saulius

    2016-08-01

    Commercially available chitins and the chitin isolated from mushrooms, insect cuticles, shells of shrimp, crab and crayfish reported in the literature are in forms of powder, flake or granule. Three-dimensional chitins have been only known from the sponges but still three-dimensional chitosan has not been reported yet. In this study, we produced three-dimensional chitin and chitosan rings from the body segments of a diplopod species (Julus terrestris). Obtained chitin and chitosan rings were characterized (by FT-IR, SEM, TGA, XRD, dilute solution viscometry and EA) and compared with commercial chitin and chitosan. The interactions with plasmid DNA was studied at varying concentrations of chitosan (0.04, 0.4 and 4mg/mL). Antitumor activity tests were conducted (L929 and HeLa), low cytotoxicity and high antiproliferative activity was observed. Antimicrobial activities of J. terrestris chitosan were investigated on twelve microorganisms and maximum inhibition (15.6±1.154mm) was recorded for common human pathogen Staphylococcus aureus. PMID:27112853

  19. Cladosporium fulvum Avr4 protects fungal cell walls against hydrolysis by plant chitinases accumulating during infection.

    Science.gov (United States)

    van den Burg, Harrold A; Harrison, Stuart J; Joosten, Matthieu H A J; Vervoort, Jacques; de Wit, Pierre J G M

    2006-12-01

    Resistance against the leaf mold fungus Cladosporium fulvum is mediated by the tomato Cf proteins which belong to the class of receptor-like proteins and indirectly recognize extracellular avirulence proteins (Avrs) of the fungus. Apart from triggering disease resistance, Avrs are believed to play a role in pathogenicity or virulence of C. fulvum. Here, we report on the avirulence protein Avr4, which is a chitin-binding lectin containing an invertebrate chitin-binding domain (CBM14). This domain is found in many eukaryotes, but has not yet been described in fungal or plant genomes. We found that interaction of Avr4 with chitin is specific, because it does not interact with other cell wall polysaccharides. Avr4 binds to chitin oligomers with a minimal length of three N-acetyl glucosamine residues. In vitro, Avr4 protects chitin against hydrolysis by plant chitinases. Avr4 also binds to chitin in cell walls of the fungi Trichoderma viride and Fusarium solani f. sp. phaseoli and protects these fungi against normally deleterious concentrations of plant chitinases. In situ fluorescence studies showed that Avr4 also binds to cell walls of C. fulvum during infection of tomato, where it most likely protects the fungus against tomato chitinases, suggesting that Avr4 is a counter-defensive virulence factor.

  20. DNA interaction, antitumor and antimicrobial activities of three-dimensional chitosan ring produced from the body segments of a diplopod.

    Science.gov (United States)

    Kaya, Murat; Akyuz, Bahar; Bulut, Esra; Sargin, Idris; Tan, Gamze; Erdonmez, Demet; Maheta, Mansi; Satkauskas, Saulius; Mickevičius, Saulius

    2016-08-01

    Commercially available chitins and the chitin isolated from mushrooms, insect cuticles, shells of shrimp, crab and crayfish reported in the literature are in forms of powder, flake or granule. Three-dimensional chitins have been only known from the sponges but still three-dimensional chitosan has not been reported yet. In this study, we produced three-dimensional chitin and chitosan rings from the body segments of a diplopod species (Julus terrestris). Obtained chitin and chitosan rings were characterized (by FT-IR, SEM, TGA, XRD, dilute solution viscometry and EA) and compared with commercial chitin and chitosan. The interactions with plasmid DNA was studied at varying concentrations of chitosan (0.04, 0.4 and 4mg/mL). Antitumor activity tests were conducted (L929 and HeLa), low cytotoxicity and high antiproliferative activity was observed. Antimicrobial activities of J. terrestris chitosan were investigated on twelve microorganisms and maximum inhibition (15.6±1.154mm) was recorded for common human pathogen Staphylococcus aureus.

  1. Evidence for a "wattle and daub" model of the cyst wall of entamoeba.

    Science.gov (United States)

    Chatterjee, Anirban; Ghosh, Sudip K; Jang, Ken; Bullitt, Esther; Moore, Landon; Robbins, Phillips W; Samuelson, John

    2009-07-01

    The cyst wall of Entamoeba invadens (Ei), a model for the human pathogen Entamoeba histolytica, is composed of fibrils of chitin and three chitin-binding lectins called Jacob, Jessie3, and chitinase. Here we show chitin, which was detected with wheat germ agglutinin, is made in secretory vesicles prior to its deposition on the surface of encysting Ei. Jacob lectins, which have tandemly arrayed chitin-binding domains (CBDs), and chitinase, which has an N-terminal CBD, were each made early during encystation. These results are consistent with their hypothesized roles in cross-linking chitin fibrils (Jacob lectins) and remodeling the cyst wall (chitinase). Jessie3 lectins likely form the mortar or daub of the cyst wall, because 1) Jessie lectins were made late during encystation; 2) the addition to Jessie lectins to the cyst wall correlated with a marked decrease in the permeability of cysts to nucleic acid stains (DAPI) and actin-binding heptapeptide (phalloidin); and 3) recombinant Jessie lectins, expressed as a maltose-binding proteins in the periplasm of Escherichia coli, caused transformed bacteria to agglutinate in suspension and form a hard pellet that did not dissociate after centrifugation. Jessie3 appeared as linear forms and rosettes by negative staining of secreted recombinant proteins. These findings provide evidence for a "wattle and daub" model of the Entamoeba cyst wall, where the wattle or sticks (chitin fibrils likely cross-linked by Jacob lectins) is constructed prior to the addition of the mortar or daub (Jessie3 lectins).

  2. Mode of action of etoxazole.

    Science.gov (United States)

    Nauen, Ralf; Smagghe, Guy

    2006-05-01

    The mode of action of the 2,4-diphenyl-1,3-oxazoline acaricide/insecticide etoxazole has been argued to be moulting inhibition, but experimental results supporting this hypothesis are lacking. This study investigated the effect of etoxazole on chitin biosynthesis in the fall armyworm, Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae). Etoxazole induced moulting defects in fall armyworm larvae similar, if not identical, to those caused by benzoylphenylureas, a well-known class of insecticidal chitin biosynthesis inhibitors. Furthermore, in contrast to untreated larvae, the chitin content in the integuments of larvae several days after treatment did not differ from that in freshly ecdysed individuals, thus suggesting strong chitin biosynthesis inhibition in vivo. A more detailed investigation of the inhibitory potential by incubating cultured integument pieces from larvae of S. frugiperda with [14C]N-acetyl-D-glucosamine, a radiolabelled chitin precursor, revealed I50 values of 2.95 and 0.071 microM for etoxazole and triflumuron respectively. The incorporation of radiolabel into potassium hydroxide-resistant material was inhibited by etoxazole in a dose-dependent manner. Based on these results, it is concluded that the acaricidal and insecticidal mode of action of etoxazole is chitin biosynthesis inhibition. PMID:16555232

  3. Purification and characterization of chitinase from Bacillus circulans No.4.1.

    Science.gov (United States)

    Wiwat, C; Siwayaprahm, P; Bhumiratana, A

    1999-09-01

    Bacillus circulans No.4.1 produced a high level of chitinase when cells were grown in tryptic soy broth supplemented with 0.3% colloidal chitin at 35 degrees C for 5 days. Purification was carried out by protein precipitation with 80% saturation ammonium sulfate, anion-exchange chromatography with DEAE-Sephacel, and gel filtration with Sephadex G-100, sequentially. The purified enzyme could be demonstrated as a single band on SDS-PAGE, estimated to be 45 kDa. This enzyme could hydrolyze colloidal chitin, purified chitin, glycol chitin, carboxymethyl-chitin (CM-chitin), and 4-methylumbelliferyl-beta-D-N,N'-diacetylchitobioside [4-MU-(GlcNAc)(2)]. The optimal conditions for this chitinase were pH 8.0 and 40 degrees C. The isoelectric point of the chitinase was 5.1. The amino acid composition of the purified chitinase was determined. The initial 20 amino acid residues of the N-terminal were found to be alanine (A), proline (P), tryptophan (W), asparagine (N), serine (S), lysine (K), glycine (G), asparagine (N), tyrosine (Y), alanine (A), leucine (L), proline (P), tyrosine (Y), tyrosine (Y), arginine (R), glycine (G), alanine (A), tryptophan (W), alanine (A), and valine (V). Knowledge of these properties of chitinase from B. circulans No. 4.1 should be useful in the development of genetically engineered Bacillus sp. as biopesticides. PMID:10441726

  4. Multifunctional layered magnetic composites

    Directory of Open Access Journals (Sweden)

    Maria Siglreitmeier

    2015-01-01

    Full Text Available A fabrication method of a multifunctional hybrid material is achieved by using the insoluble organic nacre matrix of the Haliotis laevigata shell infiltrated with gelatin as a confined reaction environment. Inside this organic scaffold magnetite nanoparticles (MNPs are synthesized. The amount of MNPs can be controlled through the synthesis protocol therefore mineral loadings starting from 15 wt % up to 65 wt % can be realized. The demineralized organic nacre matrix is characterized by small-angle and very-small-angle neutron scattering (SANS and VSANS showing an unchanged organic matrix structure after demineralization compared to the original mineralized nacre reference. Light microscopy and confocal laser scanning microscopy studies of stained samples show the presence of insoluble proteins at the chitin surface but not between the chitin layers. Successful and homogeneous gelatin infiltration in between the chitin layers can be shown. The hybrid material is characterized by TEM and shows a layered structure filled with MNPs with a size of around 10 nm. Magnetic analysis of the material demonstrates superparamagnetic behavior as characteristic for the particle size. Simulation studies show the potential of collagen and chitin to act as nucleators, where there is a slight preference of chitin over collagen as a nucleator for magnetite. Colloidal-probe AFM measurements demonstrate that introduction of a ferrogel into the chitin matrix leads to a certain increase in the stiffness of the composite material.

  5. Evaluation of the Effect of Ecologic on Root Knot Nematode, Meloidogyne incognita, and Tomato Plant, Lycopersicon esculenum

    Directory of Open Access Journals (Sweden)

    Gary W. Lawrence

    2008-06-01

    Full Text Available Nonchemical methods and strategies for nematode management including cultural methods and engineered measures have been recommended as an alternative to methyl bromide (a major soil fumigant, due to its role in the depletion of the ozone layer. Hence, an international agreement has recently been reached calling for its reduced consumption and complete phasing out. This present research evaluates the potential of Ecologic, a biological, marine shell meal chitin material, as a soil amendment management agent for root knot nematode, Meloidogyne incognita, control, and its effect on the growth of Floradel tomato plant, Lycopersicon esculentum. To accomplish this goal, studies were conducted during which, experimental pots were set up in greenhouse environments using sterilized soil inoculated with 5,000 root-knot eggs per 1500 g soil. There were 4 treatments and 5 replications. Treatments were: No chitin; 50 g chitin; 100 g chitin; and 200 g chitin. A two-week wait period following Ecologic amendment preceded Floradel tomato planting to allow breakdown of the chitin material into the soil. Fresh and dry weights of shoot and root materials were taken as growth end-points. A statistically significant difference (p ≤ 0.05 was obtained with regard to the growth rate of L. esculentum at 100 g chitin treatment compared to the control with no chitin. Mean fresh weights of Floradel tomato were 78.0 ± 22.3g, 81.0 ± 20.3g, 109.0 ± 25.4g and 102.0 ± 33.3g at 0, 50, 100 and 200g chitin, respectively. The analysis of root knot nematode concentrations indicated a substantial effect on reproduction rate associated with chitin amendment. Study results showed a significant decrease in both root knot nematode eggs and juveniles (J2 at 100g and 200g Ecologic chitin levels, however, an increase in nematode concentrations was recorded at the 50g Ecologic chitin level (p ≤ 0.05. The mean amounts of J2 population, as

  6. Ultrastructure of the Interlamellar Membranes of the Nacre of the Bivalve Pteria hirundo, Determined by Immunolabelling.

    Science.gov (United States)

    Osuna-Mascaró, Antonio J; Cruz-Bustos, Teresa; Marin, Frédéric; Checa, Antonio G

    2015-01-01

    The current model for the ultrastructure of the interlamellar membranes of molluscan nacre imply that they consist of a core of aligned chitin fibers surrounded on both sides by acidic proteins. This model was based on observations taken on previously demineralized shells, where the original structure had disappeared. Despite other earlier claims, no direct observations exist in which the different components can be unequivocally discriminated. We have applied different labeling protocols on non-demineralized nacreous shells of the bivalve Pteria. With this method, we have revealed the disposition and nature of the different fibers of the interlamellar membranes that can be observed on the surface of the nacreous shell of the bivalve Pteria hirundo by high resolution scanning electron microscopy (SEM). The minor chitin component consists of very thin fibers with a high aspect ratio and which are seemingly disoriented. Each fiber has a protein coat, which probably forms a complex with the chitin. The chitin-protein-complex fibers are embedded in an additional proteinaceous matrix. This is the first time in which the sizes, positions and distribution of the chitin fibers have been observed in situ.

  7. Ultrastructure of the Interlamellar Membranes of the Nacre of the Bivalve Pteria hirundo, Determined by Immunolabelling.

    Directory of Open Access Journals (Sweden)

    Antonio J Osuna-Mascaró

    Full Text Available The current model for the ultrastructure of the interlamellar membranes of molluscan nacre imply that they consist of a core of aligned chitin fibers surrounded on both sides by acidic proteins. This model was based on observations taken on previously demineralized shells, where the original structure had disappeared. Despite other earlier claims, no direct observations exist in which the different components can be unequivocally discriminated. We have applied different labeling protocols on non-demineralized nacreous shells of the bivalve Pteria. With this method, we have revealed the disposition and nature of the different fibers of the interlamellar membranes that can be observed on the surface of the nacreous shell of the bivalve Pteria hirundo by high resolution scanning electron microscopy (SEM. The minor chitin component consists of very thin fibers with a high aspect ratio and which are seemingly disoriented. Each fiber has a protein coat, which probably forms a complex with the chitin. The chitin-protein-complex fibers are embedded in an additional proteinaceous matrix. This is the first time in which the sizes, positions and distribution of the chitin fibers have been observed in situ.

  8. Ultrastructural studies on the nematode Xiphinema diversicaudatum: Egg shell formation.

    Science.gov (United States)

    Bleve-Zacheo, T; Melillo, M T; Zacheo, G

    1993-06-01

    The ultrastructure of the formation of the egg shell in the longidorid nematode Xiphinema diversicaudatum is described. Upon fertilization a vitelline membrane, which constitutes the vitelline layer of the egg shell, is formed. The chitinous layer is secreted in the perivitelline space, between the vitelline layer and the egg cell membrane. On completion of the chitinous layer, the material of the lipid layer is extruded from the egg cytoplasm to the outer surface, through finger-like projections. Both chitinous and lipid layers are secreted by granules in the egg cytoplasm that disappear as the layers are completed. Chitinous and lipid layers are formed during the passage of the egg through the oviduct. The vitelline layer is enriched with secretions produced by the oviduct cells and then by phospholipids secreted by the cells of the pars dilatata oviductus. The inner uterine layer is also formed by deposition of secretory products apposed on the egg shell in the distal uterine region and Z-differentiation. In the proximal part of the uterus, the egg has a discontinuous electron-dense layer, the external uterine layer. Tangential sections between chitinous and uterine layers revealed the presence of holes, possibly egg pores, delimited by the two uterine layers.

  9. The Chitinolytic Activities of Streptomyces sp. TH-11

    Directory of Open Access Journals (Sweden)

    Chun-Yi Liau

    2010-12-01

    Full Text Available Chitin is an abundant biopolymer composed of units of N-acetyl-D-glucosamine linked by b-1,4 glycosidic bonds. Chitin is the main component of the shells of mollusks, the cell wall of fungi and yeast and of the exoskeleton of crustaceans and insects. The degradation of chitin is catalyzed by chitinases that occur in a wide range of organisms. Among them, the chitinases from microorganisms are extremely important for the degradation and recycling of the carbon and nitrogen trapped in the large amount of insoluble chitin in nature. Streptomyces sp. TH-11 was isolated from the sediment of the Tou-Chien River, Taiwan. The chitinolytic enzyme activities were detected using a rapid in-gel detection method from the cell-free preparation of the culture medium of TH-11. The chitinolytic enzyme activity during prolonged liquid culturing was also analyzed by direct measurement of the chitin consumption. Decomposition of the exoskeleton of shrimps was demonstrated using electron microscopy and atomic force microscopy.

  10. Synthesis of hydroxyapatite in the presence of biologically significant molecules

    International Nuclear Information System (INIS)

    In bone mineralization non-collagenous phosphoproteins containing polycarboxylate sequences are thought to control crystal nucleation and to subsequently modify crystal growth. Invertebrate calcified tissues may also contain significant amounts of phosphoserine and/or acidic amino acid residues together with chitin (a polysaccharide). The present study investigated the effect of synthetic phosphorylated compounds as well as monomeric/polymeric carboxylic acid compounds on the formation of hydroxyapatite (HAp) under conditions of physiological pH, temperature and ionic strength. Poly-L-sodium aspartate was found to have the greatest inhibitory effect; only octacalcium phosphate (a known precursor of hydroxyapatite) could be detected in the presence of this polymer. Resultant minerals showed a variety of aggregation states. The biomimetically formed calcium phosphate minerals were identified and characterised by a variety of analytical thechniques, including laser Raman, Fourier-transform infrared (FT-IR) spectroscopy, scanning electron microscopy and x-ray diffraction analysis. In addition, a series of experiments were performed to induce the formation of HAp on biogenic substrates, such as chitin and its derivatives, chitosan, reconstituted chitin and phosphorylated chitin. Granular aggregates of hydroxyapatite could be induced to form directly on phosphorylated chitin surfaces, but not on other biogenically-derived substrates. Copyright (2000) The Australian Ceramic Society

  11. An important developmental role for oligosaccharides during early embryogenesis of cyprinid fish.

    Science.gov (United States)

    Bakkers, J; Semino, C E; Stroband, H; Kijne, J W; Robbins, P W; Spaink, H P

    1997-07-22

    Derivatives of chitin oligosaccharides have been shown to play a role in plant organogenesis at nanomolar concentrations. Here we present data which indicate that chitin oligosaccharides are important for embryogenesis in vertebrates. We characterize chitin oligosaccharides synthesized in vitro by zebrafish and carp embryos in the late gastrulation stage by incorporation of radiolabeled N-acetyl-D-[U14C]glucosamine and by HPLC in combination with enzymatic conversion using the Bradyrhizobium NodZ alpha-1, 6-fucosyltransferase and chitinases. A rapid and sensitive bioassay for chitin oligosaccharides was also used employing suspension-cultured plant cells of Catharanthus roseus. We show that chitin oligosaccharide synthase activity is apparent only during late gastrulation and can be inhibited by antiserum raised against the Xenopus DG42 protein. The DG42 protein, a glycosyltransferase, is transiently expressed between midblastula and neurulation in Xenopus and zebrafish embryogenesis. Microinjection of the DG42 antiserum or the Bradyrhizobium NodZ enzyme in fertilized eggs of zebrafish led to severe defects in trunk and tail development.

  12. Co-delivery of cell-wall-forming enzymes in the same vesicle for coordinated fungal cell wall formation.

    Science.gov (United States)

    Schuster, Martin; Martin-Urdiroz, Magdalena; Higuchi, Yujiro; Hacker, Christian; Kilaru, Sreedhar; Gurr, Sarah J; Steinberg, Gero

    2016-01-01

    Fungal cells are surrounded by an extracellular cell wall. This complex matrix of proteins and polysaccharides protects against adverse stresses and determines the shape of fungal cells. The polysaccharides of the fungal wall include 1,3-β-glucan and chitin, which are synthesized by membrane-bound synthases at the growing cell tip. A hallmark of filamentous fungi is the class V chitin synthase, which carries a myosin-motor domain. In the corn smut fungus Ustilago maydis, the myosin-chitin synthase Mcs1 moves to the plasma membrane in secretory vesicles, being delivered by kinesin-1 and myosin-5. The myosin domain of Mcs1 enhances polar secretion by tethering vesicles at the site of exocytosis. It remains elusive, however, how other cell-wall-forming enzymes are delivered and how their activity is coordinated post secretion. Here, we show that the U. maydis class VII chitin synthase and 1,3-β-glucan synthase travel in Mcs1-containing vesicles, and that their apical secretion depends on Mcs1. Once in the plasma membrane, anchorage requires enzyme activity, which suggests co-synthesis of chitin and 1,3-β-glucan polysaccharides at sites of exocytosis. Thus, delivery of cell-wall-forming enzymes in Mcs1 vesicles ensures local foci of fungal cell wall formation. PMID:27563844

  13. The LysM Receptor-Like Kinase LysM RLK1 Is Required to Activate Defense and Abiotic-Stress Responses Induced by Overexpression of Fungal Chitinases in Arabidopsis Plants

    Institute of Scientific and Technical Information of China (English)

    Yariv Brotman; Ada Viterbo; Udi Landau; Smadar Pnini; Jan Lisec; Salma Balazadeh; Bernd Mueller-Roeber; Aviah Zilberstein; Lothar Willmitzer; Ilan Chet

    2012-01-01

    Application of crab shell chitin or pentamer chitin oligosaccharide to Arabidopsis seedlings increased tolerance to salinity in wild-type but not in knockout mutants of the LysM Receptor-Like Kinase1 (CERK1/LysM RLK1) gene,known to play a critical role in signaling defense responses induced by exogenous chitin.Arabidopsis plants overexpressing the endochitinase chit36 and hexoaminidase excy1 genes from the fungus Trichoderma asperelleoides T203 showed increased tolerance to salinity,heavy-metal stresses,and Botrytis cinerea infection.Resistant lines,overexpressing fungal chitinases at different levels,were outcrossed to lysm rlk1 mutants.Independent homozygous hybrids lost resistance to biotic and abiotic stresses,despite enhanced chitinase activity.Expression analysis of 270 stress-related genes,including those induced by reactive oxygen species (ROS) and chitin,revealed constant up-regulation (at least twofold) of 10 genes in the chitinase-overexpressing line and an additional 76 salt-induced genes whose expression was not elevated in the lysm rlk1 knockout mutant or the hybrids harboring the mutation.These findings elucidate that chitin-induced signaling mediated by LysM RLK1 receptor is not limited to biotic stress response but also encompasses abiotic-stress signaling and can be conveyed by ectopic expression of chitinases in plants.

  14. Electrospinnability of bionanocomposites with high nanocrystal loadings: The effect of nanocrystal surface characteristics.

    Science.gov (United States)

    Naseri, Narges; Mathew, Aji P; Oksman, Kristiina

    2016-08-20

    This paper deals with the effect of solution properties and nanoparticle surface chemistry on the spinnability of a chitosan/polyethylene oxide (PEO) with high concentration (50wt%) of chitin and cellulose nanocrystals and the properties of the resultant nanocomposite fibers/fiber mats. Electrospinning dispersions with cellulose nanocrystals having sulphate surface groups showed poor spinnability compared to chitin nanocrystals with amide and amino groups. Chitin nanocrystal based dispersions showed good spinnability and continuous fiber formation whereas cellulose nanocrystal system showed discontinuous fibers and branching. The viscosity and surface tension are shown to impact this behavior, but conductivity did not. Poor spinnability observed for cellulose nanocrystal based fibers was attributed to the coagulation of negatively charged cellulose nanocrystals and positively charged chitosan. The study showed that the nanocrystal surface charge and interactions with the chitosan/PEO matrix have a significant impact on the spinnability of bionanocomposites. PMID:27178953

  15. Purificação e caracterização da quitinase de uva (Vitis vinífera L. cv Red Globe para a produção de quitosana a partir de quitina de camarão

    Directory of Open Access Journals (Sweden)

    Laidson Paes Gomes

    2010-01-01

    Full Text Available Chitinase is produced by a wide variety of plants as a defense against peste attacks. In this study, grape chitinases were purified 16 times by fractionation in 80% ammonium sulfate followed by dialysis and filtration. Purified chitinases exhibited enzymatic activity toward chitin azure. The yield of purified chitinase was 229 mg/L with chitinase activity of 563 U/g. Chitinases had molecular masses of 24 and 30 kDa, as evaluated by SDS-PAGE 12.5%. Two pH optima were determined 3.0 and 6.0. The optimal temperature was 42 °C. Pre hydrolysis of crystalline shrimp chitin by chitinases caused in an increase in the deacetylation ratio triggered by chitin deacetylase producing chitooligosaccharides with DA (degree acetylation of 58.8%.

  16. Evaluation of physical, chemical and irradiation parameters on crab shell's chitosan obtention process

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Maiara S.; Moura, Eduardo de; Geraldo, Aurea B.C., E-mail: maiaraferreira@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    Chitin it is found in exoskeletons of crustaceans and in the cellular wall of fungi. Chitosan is obtained through the stages of deproteinization, demineralization and deacetylation. Specially, crab shells present in their composition 15-20% of chitin, 25-40% of proteins and 40-55% calcium carbonate. The demineralization step aims to reduce the inorganic ions content and is realized under hydrochloric acid dissolution. The deproteinization has the function of reducing the proteins and aminoacids by sodium hydroxide solution added to the raw material. In this work, the experimental design used to determine the best steps conditions for the production of final product - chitosan from chitin of crab shells - had been time (10, 30, 60 and 120 minutes), concentration, relation reagent solution/raw material quantity and irradiation parameters (radiation font, dose and dose rate). The results are discussed in terms of total inorganic materials and proteins quantification and of thermal analysis. (author)

  17. PROSPECTS FOR APPLICATION OF Aplysinidae FAMILY MARINE SPONGE SKELETONS AND MESENCHYMAL STROMAL CELLS IN TISSUE ENGINEERING

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    О. Yu. Rogulska

    2011-10-01

    Full Text Available Development of the new types of tissue engineered structures is one of the promising trends of current biotechnology. The study was directed to the assessment of prospects for the application of chitin-based skeletons derived from marine sponges of Aplysinidae family (Aplysina fulva and Aplysina aerophoba for creation of bioengineered constructs based on human mesenchymal stromal cells. After cleaning and demineralization procedures, sponge skeletons appeared as three-dimensional macroporous matrices formed by intersecting chitin fibrils. After seeding into chitin-based matrices the cells were attached to the surface of the fibrils and were able to spread and proliferate. Mesenchymal stromal cells within Aplysina fulva differentiated into osteogenic and adipogenic directions under the influence of appropriate inductors. Demineralized skeletons derived from marine sponges of Aplysinidae family could be used as scaffolds for mesenchymal stromal cells which provides new opportunities for the creation of adipose and bone tissue engineered structures.

  18. Regulation of competence-mediated horizontal gene transfer in the natural habitat of Vibrio cholerae.

    Science.gov (United States)

    Metzger, Lisa C; Blokesch, Melanie

    2016-04-01

    The human pathogen Vibrio cholerae is an autochthonous inhabitant of aquatic environments where it often interacts with zooplankton and their chitinous molts. Chitin induces natural competence for transformation in V. cholerae, a key mode of horizontal gene transfer (HGT). Recent comparative genomic analyses were indicative of extensive HGT in this species. However, we can still expand our understanding of the complex regulatory network that drives competence in V. cholerae. Here, we present recent advances, including the elucidation of bipartite competence regulation mediated by QstR, the inclusion of the type VI secretion system in the competence regulon of pandemic O1 El Tor strains, and the identification of TfoS as a transcriptional regulator that links chitin to competence induction in V. cholerae. PMID:26615332

  19. Production of chitinolytic enzymes with Trichoderma longibrachiatum IMI 92027 in solid substrate fermentation

    Institute of Scientific and Technical Information of China (English)

    Krisztina Kovacs; Gyorgy Szakacs; Tunde Pusztahelyi; Ashok Pandey

    2004-01-01

    @@ Thirty Trichoderna strains representing 15 species within the genus have been screened for extracellular production of chitinolytic enzymes in solid substrate fermentation (SSF). T.longibrachiatum IMI 92027 ( = ATCC 36838) gave the highest yield (5.0 IU/g dry matter of substrate) after 3 days of fermentation on wheat bran-crude chitin (9:1 mixture) medium. The optimum moisture content (66.7 %), chitin content (20 %), initial pH of the medium (2-5) and time course (5 d) of SSF were determined for strain IMI 92027. No significant effect of different N and P additives was found on the chitinase yield in wheat bran-chitin mixture medium.

  20. Chitosan in Plant Protection

    Directory of Open Access Journals (Sweden)

    Abdelbasset El Hadrami

    2010-03-01

    Full Text Available Chitin and chitosan are naturally-occurring compounds that have potential in agriculture with regard to controlling plant diseases. These molecules were shown to display toxicity and inhibit fungal growth and development. They were reported to be active against viruses, bacteria and other pests. Fragments from chitin and chitosan are known to have eliciting activities leading to a variety of defense responses in host plants in response to microbial infections, including the accumulation of phytoalexins, pathogen-related (PR proteins and proteinase inhibitors, lignin synthesis, and callose formation. Based on these and other proprieties that help strengthen host plant defenses, interest has been growing in using them in agricultural systems to reduce the negative impact of diseases on yield and quality of crops. This review recapitulates the properties and uses of chitin, chitosan, and their derivatives, and will focus on their applications and mechanisms of action during plant-pathogen interactions.