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Sample records for chitin deacetylases properties

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

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    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.

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

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    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.

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

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    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.

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

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    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.

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

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

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

    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

  7. 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

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    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.

  8. Mechanical Properties Of Calcium Carbonate Crystallization Of Chitin Reinforced Polymer

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    Michael Ikpi Ofem

    2015-08-01

    Full Text Available ABSTRACT Chitin whiskers and CaCO3 were reinforced with Polyacrylic acid. Mechanical and thermal properties were characterised. The effect of CaCO3 growth on the mechanical properties of chitin whiskers reinforced Polyacrylic acid indicated that better mechanical properties can be achieved at chitin content of 3 wt when compared with neat PAA. The growth of CaCO3 on CHWPAA composite increased the melting endotherm of CHWPAACaCO3 composite when compared with CHWPAA composite. As an indication of increase in thermal stability the final weight loss at the end of decomposition for all composites was between 20 and 37 far below the 78 for the CHWPAA composite and 84 for the pure PAA .

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

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    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.

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

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    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.

  11. Effects of supercritical water and mechanochemical grinding treatments on physicochemical properties of chitin.

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    Osada, Mitsumasa; Miura, Chika; Nakagawa, Yuko S; Kaihara, Mikio; Nikaido, Mitsuru; Totani, Kazuhide

    2013-02-15

    This study examined the effects of a combined pretreatment with supercritical water and mechanochemical grinding with a ball mill on the physicochemical properties of chitin and its enzymatic degradation. Following pretreatment with a combination of supercritical water and grinding, chitin had a lower mean molecular weight, a lower crystallinity index, a lower crystallite size, greater d-spacing, weaker hydrogen bonds, and the amide group was more exposed compared with untreated chitin. These properties increased the hydrophilicity of the chitin and enhanced its enzymatic degradation. The N,N'-diacetylchitobiose (GlcNAc)(2) yield after enzymatic degradation of chitin following pretreatment with supercritical water (400 °C, 1 min) and grinding (800 rpm, 10 min) was 93%, compared with 5% without any treatment, 37% with supercritical water pretreatment alone (400 °C, 1 min), and 60% with grinding alone (800 rpm, 30 min).

  12. Thermal Properties Of Chitin Whiskers Reinforced PolyAcrylic Acid

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    Michael Ikpi Ofem

    2015-08-01

    Full Text Available ABSTRACT Thermal analysisTGA of samples of Chitin PAA and Chitin-PAA complexes containing different weight fractions of chitin whiskers were investigated. The activation energies Ea and other kinematic parameters amp916S amp916H and amp916G for the filler matrix and blend were calculated using the Coats and Redfern Broido and Horowitz and Metzger methods at the second and third stages of decomposition. The study showed that the kinetic parameters for the composites lie between the matrix and the filler. .At each filler loading level the activation energies changes in enthalpies entropies and Gibbs functions obtained using all three methods are comparable for the second region of decomposition. The pattern is such that the value of these energy parameters gradually decreased as filler loading decreases. The gradual increase in activation energy as filler increases is attributed to even dispersion of the whiskers and interfacial adhesion between the matrix and the chitin whiskers.

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

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

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

    2015-11-09

    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.

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

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    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.

  16. 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.

  17. Biological adhesive based on carboxymethyl chitin derivatives and chitin nanofibers.

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    Azuma, Kazuo; Nishihara, Masahiro; Shimizu, Haruki; Itoh, Yoshiki; Takashima, Osamu; Osaki, Tomohiro; Itoh, Norihiko; Imagawa, Tomohiro; Murahata, Yusuke; Tsuka, Takeshi; Izawa, Hironori; Ifuku, Shinsuke; Minami, Saburo; Saimoto, Hiroyuki; Okamoto, Yoshiharu; Morimoto, Minoru

    2015-02-01

    Novel biological adhesives made from chitin derivatives were prepared and evaluated for their adhesive properties and biocompatibility. Chitin derivatives with acrylic groups, such as 2-hydroxy-3-methacryloyloxypropylated carboxymethyl chitin (HMA-CM-chitin), were synthesized and cured by the addition of an aqueous hydrogen peroxide solution as a radical initiator. The adhesive strength of HMA-CM-chitin increased when it was blended with chitin nanofibers (CNFs) or surface-deacetylated chitin nanofibers (S-DACNFs). HMA-CM-chitin/CNFs or HMA-CM-chitin/S-DACNFs have almost equal adhesive strength compared to that of a commercial cyanoacrylate adhesive. Moreover, quick adhesion and induction of inflammatory cells migration were observed in HMA-CM-chitin/CNF and HMA-CM-chitin/S-DACNF. These findings indicate that the composites prepared in this study are promising materials as new biological adhesives.

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

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    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.

  19. Crystalline structure and thermal property characterization of chitin from Antarctic krill (Euphausia superba).

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    Wang, Yanchao; Chang, Yaoguang; Yu, Long; Zhang, Cuiyu; Xu, Xiaoqi; Xue, Yong; Li, Zhaojie; Xue, Changhu

    2013-01-30

    Antarctic krill (Euphausia superba) has been widely studied and extensively recognized as a target for commercial fishing. In this study, Antarctic krill chitin was extracted from defatted Antarctic krill shell, and its crystalline structure and thermal properties were characterized by employing Fourier transform infrared spectroscopy, X-ray diffractometry, scanning electron microscopy, thermogravimetry, and differential scanning calorimetry. Results showed that Antarctic krill chitin corresponded to the α-polymorph, and was composed of small, stable, and uniform microcrystals. The degree of N-deacetylation was 11.28 ± 0.86%. The d-spacings of Antarctic krill chitin were 9.78 Å and 4.63 Å at (020) and (110) planes. The crystalline sizes were 6.07 nm and 5.16 nm at (020) and (110) planes, respectively. The activation energy of the polysaccharide chain decomposition was 123.35 kJ/mol and the glass transition (T(g)) of Antarctic krill chitin was 164.96 °C.

  20. Control of mechanical properties of chitin nanofiber film using glycerol without losing its characteristics.

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    Ifuku, Shinsuke; Ikuta, Akiko; Izawa, Hironori; Morimoto, Minoru; Saimoto, Hiroyuki

    2014-01-30

    Surface-deacetylated chitin nanofiber films plasticized with glycerol were prepared to control mechanical properties. Nanofiber networks were able to retain excessive glycerol content up to 70% to obtain self-standing film. All films were flexible and highly transparent independent of glycerol content. Glycerol significantly decreased the Young's moduli and tensile strengths, and increased the fracture strain due to its plasticizing effect. At the same time, glycerol did not change the high transparency or the low thermal expansion of the nanofiber film.

  1. The Chitin Connection

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    Goldman, David L.; Vicencio, Alfin G.

    2012-01-01

    ABSTRACT Chitin, a polymer of N-acetylglucosamine, is an essential component of the fungal cell wall. Chitosan, a deacetylated form of chitin, is also important in maintaining cell wall integrity and is essential for Cryptococcus neoformans virulence. In their article, Gilbert et al. [N. M. Gilbert, L. G. Baker, C. A. Specht, and J. K. Lodge, mBio 3(1):e00007-12, 2012] demonstrate that the enzyme responsible for chitosan synthesis, chitin deacetylase (CDA), is differentially attached to the cell membrane and wall. Bioactivity is localized to the cell membrane, where it is covalently linked via a glycosylphosphatidylinositol (GPI) anchor. Findings from this study significantly enhance our understanding of cryptococcal cell wall biology. Besides the role of chitin in supporting structural stability, chitin and host enzymes with chitinase activity have an important role in host defense and modifying the inflammatory response. Thus, chitin appears to provide a link between the fungus and host that involves both innate and adaptive immune responses. Recently, there has been increased attention to the role of chitinases in the pathogenesis of allergic inflammation, especially asthma. We review these findings and explore the possible connection between fungal infections, the induction of chitinases, and asthma. PMID:22448043

  2. 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.

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

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    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.

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

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

    2007-02-01

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

  5. Effect of sub- and supercritical water treatments on the physicochemical properties of crab shell chitin and its enzymatic degradation.

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    Osada, Mitsumasa; Miura, Chika; Nakagawa, Yuko S; Kaihara, Mikio; Nikaido, Mitsuru; Totani, Kazuhide

    2015-12-10

    This study examined the effects of sub- and supercritical water pretreatments on the physicochemical properties of crab shell α-chitin and its enzymatic degradation to obtain N,N'-diacetylchitobiose (GlcNAc)2. Following sub- and supercritical water pretreatments, the protein in the crab shell was removed and the residue of crab shell contained α-chitin and CaCO3. Prolonged pretreatment led to α-chitin decomposition. The reaction of pure α-chitin in sub- and supercritical water pretreatments was investigated separately; we observed lower mean molecular weight and weaker hydrogen bonds compared with untreated α-chitin. (GlcNAc)2 yields from enzymatic degradation of subcritical (350 °C, 7 min) and supercritical water (400 °C, 2.5 min) pretreated crab shell were 8% and 6%, compared with 0% without any pretreatment. This study shows that sub- and supercritical water pretreatments of crab shell provide to an alternative method to the use of acid and base for decalcification and deproteinization of crab shell required for (GlcNAc)2 production.

  6. Effect of soluble polysaccharides addition on rheological properties and microstructure of chitin nanocrystal aqueous dispersions.

    Science.gov (United States)

    Tzoumaki, Maria V; Moschakis, Thomas; Biliaderis, Costas G

    2013-06-05

    Mixtures of chitin nanocrystal aqueous dispersions (at pH 3.0) with soluble polysaccharides of varying molecular features were examined rheologically and microscopically, under different conditions of biopolymer concentration, ionic strength, pH and temperature. The addition of non-adsorbing polysaccharides (guar gum, locust bean gum and xanthan) as well as oppositely charged (κ-carrageenan) to a chitin nanocrystal dispersion, resulted in a network formation and the gel strength increased with the chitin nanocrystal concentration. In contrast, the chitin nanocrystal - chitosan or - pullulan mixed dispersions did not show any network formation (tanδ>1) at the concentration range examined. An increase in ionic strength and pH also resulted in an enhanced elasticity of the chitin nanocrystal-guar gum dispersions. Furthermore, an increase in the elastic modulus, which was irreversible upon cooling, was observed upon heating the chitin nanocrystal-polysaccharide mixed dispersions.

  7. The adhesive and cohesive properties of a bacterial polysaccharide adhesin are modulated by a deacetylase.

    Science.gov (United States)

    Wan, Zhe; Brown, Pamela J B; Elliott, Ellen N; Brun, Yves V

    2013-05-01

    Bacterial exopolysaccharide synthesis is a prevalent and indispensible activity in many biological processes, including surface adhesion and biofilm formation. In Caulobacter crescentus, surface attachment and subsequent biofilm growth depend on the ability to synthesize an adhesive polar polysaccharide known as the holdfast. In this work, we show that polar polysaccharide synthesis is a conserved phenomenon among Alphaproteobacterial species closely related to C. crescentus. Among them, mutagenesis of Asticcacaulis biprosthecum showed that disruption of the hfsH gene, which encodes a putative polysaccharide deacetylase, leads to accumulation of holdfast in the culture supernatant. Examination of the hfsH deletion mutant in C. crescentus revealed that this strain synthesizes holdfast; however, like the A. biprosthecum hfsH mutant, the holdfasts are shed into the medium and have decreased adhesiveness and cohesiveness. Site-directed mutagenesis at the predicted catalytic site of C. crescentus HfsH phenocopied the ΔhfsH mutant and abolished the esterase activity of HfsH. In contrast, overexpression of HfsH increased cell adherence without increasing holdfast synthesis. We conclude that the polysaccharide deacetylase activity of HfsH is required for the adhesive and cohesive properties of the holdfast, as well as for the anchoring of the holdfast to the cell envelope.

  8. Effects of addition of straw, chitin and manure to new or recycled biofilters on their pesticides retention and degradation properties.

    Science.gov (United States)

    Genot, P; Van Huynh, N; Debongnie, Ph; Pussemier, L

    2002-01-01

    Pollution of surface and groundwater by pesticides is an increasing problem that needs to be addressed by the authorities as well as by the farmers themselves. Nowadays, some researchers are considering the numerous small spillages at the farm sites as a relevant entry route to be taken into account for predicting surface and groundwater pollution. In order to tackle this problem, several solutions exist for limiting the disposal of pesticide wastes into the environment. One such system is biopurification of farm wastes by biobed, biofilter or phytobac. In this study, the results of pesticides retention by biofilters under outdoor conditions are presented. The biofilters were filled with a mixture of a soil + peat constituent (25% by volume for each of them) and the rest (50%) with straw or with composted manure ot with chitin (in this later case at the rate of 5 g chitin per liter of substrate). The soil + peat constituent was made either of a material already challenged by pesticides (= recycled biofilters) or of untreated material (new biofilters). Selected pesticides (atrazine, carbofuran, chloridazon, chlortoluron, cyanazine, isoproturon and lenacil) were applied onto biofilters and the eluates were collected and analyzed. Two successive injections of pesticides into the biofilters were conducted. After the first pesticides application, the recycled biofilters made of soil + peat previously treated with pesticides had better retention and degradation rates than the new biofilters. Adding manure also improved these properties of biofilters. Columns made of unchallenged soil + peat and straw (new biofilters) were the least satisfactory: up to 25% of carbofuran were lost. Biofilters made of unchallenged soil + peat and chitin retained the least lenacil. Atrazine was the most retained by biofilters (either new or recycled) with added chitin. Cyanazine was almost absent in the percolates of all biofilters. After the second application of carbofuran and isoproturon

  9. 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.

  10. Biomedical Activity of Chitin/Chitosan Based Materials—Influence of Physicochemical Properties Apart from Molecular Weight and Degree of N-Acetylation

    Directory of Open Access Journals (Sweden)

    Mirko X. Weinhold

    2011-11-01

    Full Text Available The physicochemical nature of chitin and chitosan, which influences the biomedical activity of these compounds, is strongly related to the source of chitin and the conditions of the chitin/chitosan production process. Apart from widely described key factors such as weight-averaged molecular weight (MW and degree of N-acetylation (DA, other physicochemical parameters like polydispersity (MW/MN, crystallinity or the pattern of acetylation (PA have to be taken into consideration. From the biological point of view, these parameters affect a very important factor—the solubility of chitin and chitosan in water and organic solvents. The physicochemical properties of chitosan solutions can be controlled by manipulating solution conditions (temperature, pH, ionic strength, concentration, solvent. The degree of substitution of the hydroxyl and the amino groups or the degree of quaternization of the amino groups also influence the mechanical and biological properties of chitosan samples. Finally, a considerable research effort has been directed towards developing safe and efficient chitin/chitosan-based products because many factors, like the size of nanoparticles, can determine the biomedical characteristics of medicinal products. The influence of these factors on the biomedical activity of chitin/chitosan-based products is presented in this report in more detail.

  11. The Evaluation on Biological Properties of Carboxymethyl-chitosan and Carboxymethyl-chitin

    Institute of Scientific and Technical Information of China (English)

    CHANG Jing; LIU Wanshun; HAN Baoqin; LIU Bing

    2008-01-01

    Carboxymethyl-chitosan and carboxymethyl-chitin were prepared with the methods developed in our laboratory.The DS(degree of substitution) and DD (degree of deacetylation) of the carboxymethyl-chitosan were 103.14% and 97.18% respectively,while the DS of the carboxymethyl-chitin was 96.37%.Their effects on human fibroblasts,intradermal irritation test,in vitro and vivodegradability,and biocompatibility were evaluated.The results indicate that the polysaccharides at low concentrations can facilitatethe growth of human fibroblasts and the carboxymethyl-chitosan at 100 μg mL is the most effective.The polysaccharides at higherconcentrations,however,inhibit the growth of fibroblasts.The PⅡ (Primary Irritation Index) values of CM-chitosan and CM-chitinare both 0.0,which shows that they have no irritation reaction.Both of the polysaccharides show good degradability and biocompati-bility.Carboxymethyl-chitin degrades faster in vitro than carboxymethyl-chitosan.The latter,however,has no inflammatory reactionafter being implanted in vivo for 7 d and shows better biocompatibility.This study may provide a scientific basis for the use of car-boxymethyl-chitosan and carboxymethyl-chitin as biomaterials.

  12. 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+

  13. Investigation Into the Structure and Performance Properties of Chitin Fiber%甲壳素纤维结构与性能研究

    Institute of Scientific and Technical Information of China (English)

    翁毅

    2011-01-01

    对甲壳素纤维的结构性能进行了测定分析。研究表明:甲壳素纤维的纵向有沟槽,有些纤维的芯层存在空隙。甲壳素纤维的干、湿态强力比毛纤维高,干态强力基本与粘胶纤维相近。甲壳素纤维的湿强明显低于干强,但下降的幅度要低于普通粘胶。甲壳素纤维的表面比较光滑,卷曲性能较差,抱合力较差,在纺丝时需严格控制湿度。总体看目前的甲壳素纤维还需要进一步提高品质,以满足高品质甲壳素纤维类纺织产品的开发生产。%In this paper, the structure and performance properties of chitin fiber were invetigated in order to provide references to the spinning of chitin yarn. The surface groove and the hole in the core of cross section of chitin fiber were found, although the fiber surface was generally smooth. The dry and wet tensile strength of chitin fiber was higher than that of wool fiber, and dry tensile strength was comparable to rayon. The wet tensile strength of chitin fiber was significantaly decrease compared to the dry tensile strength, but the decrease ratio was lower than that of the rayon. Cohesion of the chitin fiber was worse, and the relative humidity need to be controled during spinning. Generally, the quality of chitin fiber need to be further improved to meet the requirements of the product.

  14. 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...

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

    Directory of Open Access Journals (Sweden)

    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%.

  16. 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.

  17. 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.

  18. 甲壳质敷料止血作用实验研究%Hemostatic property of a novel chitin dressing

    Institute of Scientific and Technical Information of China (English)

    姜毅; 张晓东; 段蕴铀; 查建国; 顾蔚然; 徐红霞

    2013-01-01

    Objective To evaluate the hemostatic property of a novel chitin dressing for the tropical bleeding.Methods Miniature swines' femoral arteries underwent half transection; femoral artery hemostasis model was made.The miniature swines' wounds were treated with chitin dressing 5 mm,3 mm gauze or gelfoam.Pressure of 90 mm Hg was held for 10 minutes.Hemostasis time,blood loss,characters of life,adhesion between dressings and wound were observed.Results Hemostasis time and blood loss of chitin dressing 5 mm were significantly less than those of chitin dressing 3 mm and gelfoam [(141 ± 44) s vs (264 ± 70) s,(237 ± 65) s ; (21 ± 11) ml vs (58 ±18) ml,(55 ± 19) ml].Hemostasis time and blood loss of chitin dressing 3 mm or gelfoam were similar.Successful hemostasis ratio of chitin dressing 5 mm,3 mm or gelfoam appeared no difference but all better than that of gauze [87.5 % (7/8),87.5 % (7/8),62.5% (5/8) vs 0.0% (0/5)].The chitin dressing 5 mm's capability of maintaining blood pressure was greater in comparison to that of chitin dressing 3 mm or gelfoam.Conclusion The chitin dressing 5 mm is an effective material for stopping the tropical hemorrhage.%目的 研究一种新型甲壳质敷料的止血作用.方法 取实验用小型猪,显露并横断股动脉约1/2,建立股动脉出血模型,分别外敷5 mm、3 mm两种规格的甲壳质敷料、纱布敷料、明胶海绵,局部加压到90 mm Hg(1 mm Hg=0.133 kPa)持续10 min,观察记录止血时间、敷料黏附力、止血过程中的血液丢失量.结果 5 mm规格甲壳质敷料的止血时间[(141±44)s]比3 mm规格甲壳质敷料[(264±70)s]、明胶海绵[(237 ±65)s]短,失血量[(21±11)ml]比3 mm规格甲壳质敷料[(58±18)ml]或明胶海绵[(55±19)ml]少,3 mm规格甲壳质敷料和明胶海绵效果相似.在止血成功率方面,5 mm规格甲壳质敷料、3 mm规格甲壳质敷料、明胶海绵、纱布敷料分别为87.5% (7/8)、87.5% (7/8)、62.5% (5/8)、0.0% (0/5),前3种止

  19. Polymer organogelation with chitin and chitin nanocrystals

    NARCIS (Netherlands)

    Nikiforidis, C.V.; Scholten, E.

    2015-01-01

    In this paper, we show that biodegradable and biocompatible organogels can be formed with chitin as the filler material and triglycerides as the continuous hydrophobic phase. When crude chitin was used, a large degree of aggregation was observed that prevented the formation of stable organogels. Two

  20. Biopolymer chitin: extraction and characterization; Biopolimero quitina: extracao e caracterizacao

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-07-01

    The biopolymers are materials made from renewable sources such as soybean, corn, cane sugar, cellulose and chitin. Chitin is the most abundant biopolymer found in nature, after cellulose. The chemical structure of chitin is distinguished by the hydroxyl group, of structure from cellulose, located at position C-2, which in the chitin is replaced by acetamine group. The objective of this study was to develop the chitin from exoskeletons of Litopenaeus vannamei shrimp, which are discarded as waste, causing pollutions, environmental problems and thus obtain better utilization of these raw materials. It also, show the extraction process and deacetylation of chitosan. The extraction of chitin followed steps of demineralization, desproteinization and deodorization. Chitin and chitosan were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and the thermals properties were analyzed by thermogravimetry (TG/DTG). (author)

  1. 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...

  2. 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.

  3. 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.

  4. Drosophila Chitinase 2 is expressed in chitin producing organs for cuticle formation.

    Science.gov (United States)

    Pesch, Yanina-Yasmin; Riedel, Dietmar; Behr, Matthias

    2017-01-01

    The architecture of the outer body wall cuticle is fundamental to protect arthropods against invading pathogens and numerous other harmful stresses. Such robust cuticles are formed by parallel running chitin microfibrils. Molting and also local wounding leads to dynamic assembly and disassembly of the chitin-matrix throughout development. However, the underlying molecular mechanisms that organize proper chitin-matrix formation are poorly known. Recently we identified a key region for cuticle thickening at the apical cell surface, the cuticle assembly zone, where Obstructor-A (Obst-A) coordinates the formation of the chitin-matrix. Obst-A binds chitin and the deacetylase Serpentine (Serp) in a core complex, which is required for chitin-matrix maturation and preservation. Here we present evidence that Chitinase 2 (Cht2) could be essential for this molecular machinery. We show that Cht2 is expressed in the chitin-matrix of epidermis, trachea, and the digestive system. There, Cht2 is enriched at the apical cell surface and the dense chitin-matrix. We further show that in Cht2 knockdown larvae the assembly zone is rudimentary, preventing normal cuticle formation and pore canal organization. As sequence similarities of Cht2 and the core complex proteins indicate evolutionarily conserved molecular mechanisms, our findings suggest that Cht2 is involved in chitin formation also in other insects.

  5. 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

  6. 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....

  7. 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

  8. 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, cellulose/chitin blend 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.

  9. Applications of Chitin and Its Derivatives in Biological Medicine

    Directory of Open Access Journals (Sweden)

    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.

  10. Chitin and Chitosan: Production and Application of Versatile Biomedical Nanomaterials.

    Science.gov (United States)

    Elieh-Ali-Komi, Daniel; Hamblin, Michael R

    2016-03-01

    Chitin is the most abundant aminopolysaccharide polymer occurring in nature, and is the building material that gives strength to the exoskeletons of crustaceans, insects, and the cell walls of fungi. Through enzymatic or chemical deacetylation, chitin can be converted to its most well-known derivative, chitosan. The main natural sources of chitin are shrimp and crab shells, which are an abundant byproduct of the food-processing industry, that provides large quantities of this biopolymer to be used in biomedical applications. In living chitin-synthesizing organisms, the synthesis and degradation of chitin require strict enzymatic control to maintain homeostasis. Chitin synthase, the pivotal enzyme in the chitin synthesis pathway, uses UDP-N-acetylglucosamine (UDPGlcNAc), produce the chitin polymer, whereas, chitinase enzymes degrade chitin. Bacteria are considered as the major mediators of chitin degradation in nature. Chitin and chitosan, owing to their unique biochemical properties such as biocompatibility, biodegradability, non-toxicity, ability to form films, etc, have found many promising biomedical applications. Nanotechnology has also increasingly applied chitin and chitosan-based materials in its most recent achievements. Chitin and chitosan have been widely employed to fabricate polymer scaffolds. Moreover, the use of chitosan to produce designed-nanocarriers and to enable microencapsulation techniques is under increasing investigation for the delivery of drugs, biologics and vaccines. Each application is likely to require uniquely designed chitosan-based nano/micro-particles with specific dimensions and cargo-release characteristics. The ability to reproducibly manufacture chitosan nano/microparticles that can encapsulate protein cargos with high loading efficiencies remains a challenge. Chitosan can be successfully used in solution, as hydrogels and/or nano/microparticles, and (with different degrees of deacetylation) an endless array of derivatives with

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

    Directory of Open Access Journals (Sweden)

    Anudeep Sandanamudi

    2016-12-01

    Full Text Available 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.

  12. 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.

  13. Pyrolysis of chitin biomass

    DEFF Research Database (Denmark)

    Qiao, Yan; Chen, Shuai; Liu, Ying

    2015-01-01

    The thermal degradation of chitin biomass with various molecular structures was investigated by thermogravimetric analysis (TG), and the gaseous products were analyzed by connected mass spectroscopy (MS). The chemical structure and morphology of char residues collected at 750°C using the model...

  14. Benzoylurea Chitin Synthesis Inhibitors.

    Science.gov (United States)

    Sun, Ranfeng; Liu, Chunjuan; Zhang, Hao; Wang, Qingmin

    2015-08-12

    Benzoylurea chitin synthesis inhibitors are widely used in integrated pest management (IPM) and insecticide resistance management (IRM) programs due to their low toxicity to mammals and predatory insects. In the past decades, a large number of benzoylurea derivatives have been synthesized, and 15 benzoylurea chitin synthesis inhibitors have been commercialized. This review focuses on the history of commercial benzolyphenylureas (BPUs), synthetic methods, structure-activity relationships (SAR), action mechanism research, environmental behaviors, and ecotoxicology. Furthermore, their disadvantages of high risk to aquatic invertebrates and crustaceans are pointed out. Finally, we propose that the para-substituents at anilide of benzoylphenylureas should be the functional groups, and bipartite model BPU analogues are discussed in an attempt to provide new insight for future development of BPUs.

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

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    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.

  16. 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.

  17. Inhibitors of histone deacetylase

    DEFF Research Database (Denmark)

    2015-01-01

    The present invention relates to compounds of formula (I) or a pharmaceutically acceptable salt, hydrate, solvate, or prodrug thereof, wherein X1, X2, X3, X4, X5, W1, W2, W3, and W4 are as described. The present invention relates generally to inhibitors of histone deacetylase and to methods...

  18. 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.

  19. 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.

  20. 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

  1. 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

  2. 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.

  3. Histone deacetylases and atherosclerosis.

    Science.gov (United States)

    Zheng, Xia-xia; Zhou, Tian; Wang, Xin-An; Tong, Xiao-hong; Ding, Jia-wang

    2015-06-01

    Atherosclerosis is the most common pathological process that leads to cardiovascular diseases, a disease of large- and medium-sized arteries that is characterized by a formation of atherosclerotic plaques consisting of necrotic cores, calcified regions, accumulated modified lipids, smooth muscle cells (SMCs), endothelial cells, leukocytes, and foam cells. Recently, the question about how to suppress the occurrence of atherosclerosis and alleviate the progress of cardiovascular disease becomes the hot topic. Accumulating evidence suggests that histone deacetylases(HDACs) play crucial roles in arteriosclerosis. This review summarizes the effect of HDACs and HDAC inhibitors(HDACi) on the progress of atherosclerosis.

  4. Discovery of two new inhibitors of Botrytis cinerea chitin synthase by a chemical library screening.

    Science.gov (United States)

    Magellan, Hervé; Boccara, Martine; Drujon, Thierry; Soulié, Marie-Christine; Guillou, Catherine; Dubois, Joëlle; Becker, Hubert F

    2013-09-01

    Chitin synthases polymerize UDP-GlcNAC to form chitin polymer, a key component of fungal cell wall biosynthesis. Furthermore, chitin synthases are desirable targets for fungicides since chitin is absent in plants and mammals. Two potent Botrytis cinerea chitin synthase inhibitors, 2,3,5-tri-O-benzyl-d-ribose (compound 1) and a 2,5-functionalized imidazole (compound 2) were identified by screening a chemical library. We adapted the wheat germ agglutinin (WGA) test for chitin synthase activity detection to allow miniaturization and robotization of the screen. Both identified compounds inhibited chitin synthases in vitro with IC50 values of 1.8 and 10μM, respectively. Compounds 1 and 2 were evaluated for their antifungal activity and were found to be active against B. cinerea BD90 strain with MIC values of 190 and 100μM, respectively. Finally, we discovered that both compounds confer resistance to plant leaves against the attack of the fungus by reducing the propagation of lesions by 37% and 23%, respectively. Based on the inhibitory properties found in different assays, compounds 1 and 2 can be considered as antifungal hit inhibitors of chitin synthase, allowing further optimization of their pharmacological profile to improve their antifungal properties.

  5. Short-Chain Chitin Oligomers: Promoters of Plant Growth

    Directory of Open Access Journals (Sweden)

    Alexander J. Winkler

    2017-02-01

    Full Text Available Chitin is the second most abundant biopolymer in nature after cellulose, and it forms an integral part of insect exoskeletons, crustacean shells, krill and the cell walls of fungal spores, where it is present as a high-molecular-weight molecule. In this study, we showed that a chitin oligosaccharide of lower molecular weight (tetramer induced genes in Arabidopsis that are principally related to vegetative growth, development and carbon and nitrogen metabolism. Based on plant responses to this chitin tetramer, a low-molecular-weight chitin mix (CHL enriched to 92% with dimers (2mer, trimers (3mer and tetramers (4mer was produced for potential use in biotechnological processes. Compared with untreated plants, CHL-treated plants had increased in vitro fresh weight (10%, radicle length (25% and total carbon and nitrogen content (6% and 8%, respectively. Our data show that low-molecular-weight forms of chitin might play a role in nature as bio-stimulators of plant growth, and they are also a known direct source of carbon and nitrogen for soil biomass. The biochemical properties of the CHL mix might make it useful as a non-contaminating bio-stimulant of plant growth and a soil restorer for greenhouses and fields.

  6. IMPROVING NONTHROMBOGENICITY OF CHITIN WITH ZWITTERIONIC STRUCTURE OF SULFOBETAINE

    Institute of Scientific and Technical Information of China (English)

    Jun Zhu; Chang-wang Pan; Ling Tong; Han Yan; Jian Shen; Si-cong Lin

    2005-01-01

    In order to improve the nonthrombogenicity of chitin, a new monomer, N, N-dimethyl(β-hydroxyethyloxyethyl)ammonium propanesulfonate (DHAPS) was designed, synthesized and grafted onto the chitin membrane by using hexamethylene diisocyanate (HDI) as a coupling agent. Surface analysis of the grafted membranes by ATR-FTIR and XPS confirms that DHAPS has been successfully grafted onto the membrane surface. The platelet resistant property of the grafted membranes was evaluated by a platelet-rich plasma adhesion method. The results showed that platelet-adhesive resistance of the modified membrane has been greatly improved.

  7. 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.

  8. Aqueous foams stabilized by chitin nanocrystals

    NARCIS (Netherlands)

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

    2015-01-01

    The aim of the present study was to explore the potential use of chitin nanocrystals, as colloidal rod-like particles, to stabilize aqueous foams. Chitin nanocrystals (ChN) were prepared by acid hydrolysis of crude chitin and foams were generated mainly by sonicating the respective dispersions. The

  9. 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.

  10. Chitin is endogenously produced in vertebrates.

    Science.gov (United States)

    Tang, W Joyce; Fernandez, Javier G; Sohn, Joel J; Amemiya, Chris T

    2015-03-30

    Chitin, a biopolymer of N-acetylglucosamine, is abundant in invertebrates and fungi and is an important structural molecule [1, 2]. There has been a longstanding belief that vertebrates do not produce chitin; however, we have obtained compelling evidence to the contrary. Chitin synthase genes are present in numerous fishes and amphibians, and chitin is localized in situ to the lumen of the developing zebrafish gut, in epithelial cells of fish scales, and in at least three different cell types in larval salamander appendages. Chitin synthase gene knockdowns and various histochemical experiments in zebrafish further authenticated our results. Finally, a polysaccharide was extracted from scales of salmon that exhibited all the chemical hallmarks of chitin. Our data and analyses demonstrate the existence of endogenous chitin in vertebrates and suggest that it serves multiple roles in vertebrate biology.

  11. 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.

  12. 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

  13. Construction of chitin/PVA composite hydrogels with jellyfish gel-like structure and their biocompatibility.

    Science.gov (United States)

    He, Meng; Wang, Zhenggang; Cao, Yan; Zhao, Yanteng; Duan, Bo; Chen, Yun; Xu, Min; Zhang, Lina

    2014-09-08

    High strength chitin/poly(vinyl alcohol) (PVA) composite hydrogels (RCP) were constructed by adding PVA into chitin dissolved in a NaOH/urea aqueous solution, and then by cross-linking with epichlorohydrin (ECH) and freezing-thawing process. The RCP hydrogels were characterized by field emission scanning electron microscopy, FTIR, differential scanning calorimetry, solid-state (13)C NMR, wide-angle X-ray diffraction, and compressive test. The results revealed that the repeated freezing/thawing cycles induced the bicrosslinked networks consisted of chitin and PVA crystals in the composite gels. Interestingly, a jellyfish gel-like structure occurred in the RCP75 gel with 25 wt % PVA content in which the amorphous and crystalline PVA were immobilized tightly in the chitin matrix through hydrogen bonding interaction. The freezing/thawing cycles played an important role in the formation of the layered porous PVA networks and the tight combining of PVA with the pore wall of chitin. The mechanical properties of RCP75 were much higher than the other RCP gels, and the compressive strength was 20× higher than that of pure chitin gels, as a result of broadly dispersing stress caused by the orderly multilayered networks. Furthermore, the cell culture tests indicated that the chitin/PVA composite hydrogels exhibited excellent biocompatibility and safety, showing potential applications in the field of tissue engineering.

  14. 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.

  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 Scaffolds in Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Tetsuya Furuike

    2011-03-01

    Full Text Available Tissue engineering/regeneration is based on the hypothesis that healthy stem/progenitor cells either recruited or delivered to an injured site, can eventually regenerate lost or damaged tissue. Most of the researchers working in tissue engineering and regenerative technology attempt to create tissue replacements by culturing cells onto synthetic porous three-dimensional polymeric scaffolds, which is currently regarded as an ideal approach to enhance functional tissue regeneration by creating and maintaining channels that facilitate progenitor cell migration, proliferation and differentiation. The requirements that must be satisfied by such scaffolds include providing a space with the proper size, shape and porosity for tissue development and permitting cells from the surrounding tissue to migrate into the matrix. Recently, chitin scaffolds have been widely used in tissue engineering due to their non-toxic, biodegradable and biocompatible nature. The advantage of chitin as a tissue engineering biomaterial lies in that it can be easily processed into gel and scaffold forms for a variety of biomedical applications. Moreover, chitin has been shown to enhance some biological activities such as immunological, antibacterial, drug delivery and have been shown to promote better healing at a faster rate and exhibit greater compatibility with humans. This review provides an overview of the current status of tissue engineering/regenerative medicine research using chitin scaffolds for bone, cartilage and wound healing applications. We also outline the key challenges in this field and the most likely directions for future development and we hope that this review will be helpful to the researchers working in the field of tissue engineering and regenerative medicine.

  17. 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.

  18. Solid state characterization of {alpha}-chitin from Vanessa cardui Linnaeus wings

    Energy Technology Data Exchange (ETDEWEB)

    Schiffman, Jessica D. [Department of Materials Science and Engineering, Drexel University, Philadelphia, PA (United States); Schauer, Caroline L., E-mail: cschauer@coe.drexel.edu [Department of Materials Science and Engineering, Drexel University, Philadelphia, PA (United States)

    2009-05-05

    Material properties of the painted lady butterfly, Vanessa cardui Linnaeus were investigated using typical material science techniques. The examined butterflies were raised and hatched from the larvae stage and their chemical and crystalline structure evaluated and compared to that of crab shell ({alpha}-chitin) and squid pens from Notodarus sloanii and Loligo pealei ({beta}-chitin). Fourier transmission infrared spectroscopy (FTIR) and X-ray diffraction (XRD) revealed that the painted lady butterflies are composed of {alpha}-chitin. Additionally, macro- and microstructure characterization of the chitins was conducted utilizing digital photography and field emission scanning electron microscopy (FESEM). This work demonstrates that common characterization techniques combined with simple sample preparation of biological materials can yield successful material characterization, which could aide the fabrication of biomimetic materials.

  19. Go Fly a Chitin: The Mystery of Chitin and Chitinases in Vertebrate Tissues.

    Science.gov (United States)

    Stern, Robert

    2017-01-01

    A controversy arose decades ago whether the DG42 gene product expressed during frog embryogenesis synthesized hyaluronan or chitin. Both sets of investigators were correct. It is now possible to understand how prescient those findings were. Synthesis of a seven to nine chitin sugar chain fragment is required before hyaluronan synthesis begins. Thus, DG42 indeed synthesizes both hyaluronan and chitin. Hyaluronan turns over rapidly in vertebrate tissues, but chitin oligomers are difficult to degrade. They accumulate and can cause pathology. Chitin is a simple beta-linked repeating sugar homopolymer found prominently in the building block structures of fungi, molluscs, arthropods, and other forms of invertebrate life. It is a highly resistant insoluble material requiring chitin synthases for production and chitinases for degradation. Mysteriously, chitins and chitinases also occur in vertebrate tissues, while it had previously been assumed that no chitins were contained therein. That assumption is now challenged based on recent biochemical evidence. Chitin does accumulate in many tissues, but may be particularly toxic to neurons. Its accumulation in the brain may account for the cognitive decline found in patients with Alzheimer's disease. The DG42 observations together with the participation of chitins and chitinases in several human diseases, among which in addition to Alzheimer's disease include Gaucher's disease, asthma, and aspects of abnormal immune recognition justify a reexamination of these topics. The purpose of this review is to summarize data in order to place chitins and their attendant enzymes in a rational framework in an attempt to create a cohesive story.

  20. 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.

  1. Histone Deacetylases and Cardiometabolic Diseases

    OpenAIRE

    Yiew, Kan Hui; Chatterjee, Tapan K.; Hui, David Y.; Weintraub, Neal L.

    2015-01-01

    Cardiometabolic disease, emerging as a worldwide epidemic, is a combination of metabolic derangements leading to type 2 diabetes and cardiovascular disease. Genetic and environmental factors are linked through epigenetic mechanisms to the pathogenesis of cardiometabolic disease. Post-translational modifications of histone tails, including acetylation and deacetylation, epigenetically alter chromatin structure and dictate cell-specific gene expression patterns. The histone deacetylase (HDAC) f...

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. Three-dimensional chitin-based scaffolds from Verongida sponges (Demospongiae: Porifera). Part I. Isolation and identification of chitin.

    Science.gov (United States)

    Ehrlich, H; Ilan, M; Maldonado, M; Muricy, G; Bavestrello, G; Kljajic, Z; Carballo, J L; Schiaparelli, S; Ereskovsky, A; Schupp, P; Born, R; Worch, H; Bazhenov, V V; Kurek, D; Varlamov, V; Vyalikh, D; Kummer, K; Sivkov, V V; Molodtsov, S L; Meissner, H; Richter, G; Steck, E; Richter, W; Hunoldt, S; Kammer, M; Paasch, S; Krasokhin, V; Patzke, G; Brunner, E

    2010-08-01

    Marine invertebrate organisms including sponges (Porifera) not only provide an abundant source of biologically active secondary metabolites but also inspire investigations to develop biomimetic composites, scaffolds and templates for practical use in materials science, biomedicine and tissue engineering. Here, we presented a detailed study of the structural and physico-chemical properties of three-dimensional skeletal scaffolds of the marine sponges Aiolochroia crassa, Aplysina aerophoba, A. cauliformis, A. cavernicola, and A. fulva (Verongida: Demospongiae). We show that these fibrous scaffolds have a multilayered design and are made of chitin. (13)C solid-state NMR spectroscopy, NEXAFS, and IR spectroscopy as well as chitinase digestion and test were applied in order to unequivocally prove the existence of alpha-chitin in all investigated species.

  7. Changes in enzymatic activities and microbial properties in vermicompost of water hyacinth as affected by pre-composting and fungal inoculation: a comparative study of ergosterol and chitin for estimating fungal biomass.

    Science.gov (United States)

    Pramanik, P

    2010-01-01

    In this experiment, three different fungal species, viz. Trichoderma viridae, Aspergillus niger and Phanerochaete chrysosporium, were inoculated in 7 day and 15 day partially decomposed water hyacinth to study their effect on enzymatic activities, microbial respiration and fungal biomass of the final stabilized product. The results suggested that increasing the duration of pre-composting from 7 days to 15 days did not show any significant effect on the activities of hydrolytic enzymes. Inoculation of fungi significantly (P vermicomposts. Inoculation of P. chrysosporium in initial organic waste registered the highest chitin content in vermicompost. A comparison of fungal biomass and chitin content revealed a conversion factor of 2.628 with a standard deviation of 0.318. Due to significant correlation (r = 0.864), this conversion factor allows for the calculation of fungal biomass from chitin, which is comparatively more stable than ergosterol.

  8. Characteristics of corneal lens chitin in dragonfly compound eyes.

    Science.gov (United States)

    Kaya, Murat; Sargin, Idris; Al-Jaf, Ivan; Erdogan, Sevil; Arslan, Gulsin

    2016-08-01

    Chitin in the compound eyes of arthropods serves as a part of the visual system. The quality of chitin in such highly specialised body parts deserves more detailed examination. Chitin in the corneal (ommatidial) lenses of dragonfly (Sympetrum fonscolombii) compound eyes was isolated by using the classical chemical method. The chitin content of the corneal lenses was determined to be quite high (20.3±0.85%). The FT-IR analysis showed that corneal lens chitin was in the α-form as found in all arthropod species where mechanical strength is required. The surface morphology analysis by scanning electron microscopy revealed that the outer part of corneal lenses consisted of long chitin fibrils with regular arrays of papillary structures while the smoother inner part had concentric lamellated chitin formation with shorter chitin nanofibrils. Chitinase enzymatic digestion studies, elemental analysis results and the degree of acetylation value showed the purity of chitin samples from corneal lens. The maximum degradation temperature value of the corneal lens chitin was observed at 369.2°C. X-ray analysis revealed that corneal lens chitin has high crystallinity index; 96.4%. Identification of chitin found in ommaditia of insect compound eyes can provide insights into insect vision and chitin-based optical material design studies.

  9. 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.

  10. Thin-film Nanofibrous Composite Membranes Containing Cellulose or Chitin Barrier Layers Fabricated by Ionic Liquids

    Energy Technology Data Exchange (ETDEWEB)

    H Ma; B Hsiao; B Chu

    2011-12-31

    The barrier layer of high-flux ultrafiltration (UF) thin-film nanofibrous composite (TFNC) membranes for purification of wastewater (e.g., bilge water) have been prepared by using cellulose, chitin, and a cellulose-chitin blend, regenerated from an ionic liquid. The structures and properties of regenerated cellulose, chitin, and a cellulose-chitin blend were analyzed with thermogravimetric analysis (TGA) and wide-angle X-ray diffraction (WAXD). The surface morphology, pore size and pore size distribution of TFNC membranes were determined by SEM images and molecular weight cut-off (MWCO) methods. An oil/water emulsion, a model of bilge water, was used as the feed solution, and the permeation flux and rejection ratio of the membranes were investigated. TFNC membranes based on the cellulose-chitin blend exhibited 10 times higher permeation flux when compared with a commercial UF membrane (PAN10, Sepro) with a similar rejection ratio after filtration over a time period of up to 100 h, implying the practical feasibility of such membranes for UF applications.

  11. 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.

  12. Chitin-glucan complex production by Komagataella pastoris: Downstream optimization and product characterization.

    Science.gov (United States)

    Farinha, Inês; Duarte, Paulo; Pimentel, Ana; Plotnikova, Evgeniya; Chagas, Bárbara; Mafra, Luís; Grandfils, Christian; Freitas, Filomena; Fortunato, Elvira; Reis, Maria A M

    2015-10-05

    Purified chitin-glucan complex (CGCpure) was extracted from Komagataella pastoris biomass using a hot alkaline treatment, followed by neutralization and repeated washing with deionized water. The co-polymer thus obtained had a β-glucan:chitin molar ratio of 75:25 and low protein and inorganic salts contents (3.0 and 0.9 wt%, respectively). CGCpure had an average molecular weight of 4.9 × 10(5)Da with a polydispersity index of 1.7, and a crystallinity index of 50%. Solid-state NMR provided structural insight at the co-polymer. X-ray diffraction suggests that CGCpure has α-chitin in its structure. CGCpure presented an endothermic decomposition peak at 315°C, assigned to the degradation of the saccharide structures. This study revealed that K. pastoris CGC has properties similar to other chitinous biopolymers and may represent an attractive alternative to crustacean chitin derived-products, being a reliable raw material for the development of new/improved pharmaceutical, cosmetic or food products.

  13. Chitin receptor CERK1 links salt stress and chitin-triggered innate immunity in Arabidopsis.

    Science.gov (United States)

    Espinoza, Catherine; Liang, Yan; Stacey, Gary

    2017-03-01

    In nature, plants need to respond to multiple environmental stresses that require the involvement and fine-tuning of different stress signaling pathways. Cross-tolerance, in which plants pre-treated with chitin (a fungal microbe-associated molecular pattern) have improved salt tolerance, was observed in Arabidopsis, but is not well understood. Here, we show a unique link between chitin and salt signaling mediated by the chitin receptor CHITIN ELICITOR RECEPTOR KINASE 1 (CERK1). Transcriptome analysis revealed that salt stress-induced genes are highly correlated with chitin-induced genes, although this was not observed with other microbe-associated molecular patterns (MAMPs) or with other abiotic stresses. The cerk1 mutant was more susceptible to NaCl than was the wild type. cerk1 plants had an irregular increase of cytosolic calcium ([Ca(2+) ]cyt ) after NaCl treatment. Bimolecular fluorescence complementation (BiFC) and co-immunoprecipitation experiments indicated that CERK1 physically interacts with ANNEXIN 1 (ANN1), which was reported to form a calcium-permeable channel that contributes to the NaCl-induced [Ca(2+) ]cyt signal. In turn, ann1 mutants showed elevated chitin-induced rapid responses. In short, molecular components previously shown to function in chitin or salt signaling physically interact and intimately link the downstream responses to fungal attack and salt stress.

  14. 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)

  15. Chitin Adsorbents for Toxic Metals: A Review

    Directory of Open Access Journals (Sweden)

    Ioannis Anastopoulos

    2017-01-01

    Full Text Available Wastewater treatment is still a critical issue all over the world. Among examined methods for the decontamination of wastewaters, adsorption is a promising, cheap, environmentally friendly and efficient procedure. There are various types of adsorbents that have been used to remove different pollutants such as agricultural waste, compost, nanomaterials, algae, etc., Chitin (poly-β-(1,4-N-acetyl-d-glucosamine is the second most abundant natural biopolymer and it has attracted scientific attention as an inexpensive adsorbent for toxic metals. This review article provides information about the use of chitin as an adsorbent. A list of chitin adsorbents with maximum adsorption capacity and the best isotherm and kinetic fitting models are provided. Moreover, thermodynamic studies, regeneration studies, the mechanism of adsorption and the experimental conditions are also discussed in depth.

  16. 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

  17. 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

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. Mesoporous silica and organosilica films templated by nanocrystalline chitin.

    Science.gov (United States)

    Nguyen, Thanh-Dinh; Shopsowitz, Kevin E; MacLachlan, Mark J

    2013-11-04

    Liquid crystalline phases can be used to impart order into inorganic solids, creating materials that mimic natural architectures. Herein, mesoporous silica and organosilica films with layered structures and high surface areas have been templated by nanocrystalline chitin. Aqueous suspensions of spindle-shaped chitin nanocrystals were prepared by sequential deacetylation and hydrolysis of chitin fibrils isolated from king crab shells. The nanocrystalline chitin self-assembles into a nematic liquid-crystalline phase that has been used to template silica and organosilica composites. Removal of the chitin template by either calcination or sulfuric-acid-catalyzed hydrolysis gave mesoporous silica and ethylene-bridged organosilica films. The large, crack-free mesoporous films have layered structures with features that originate from the nematic organization of the nanocrystalline chitin.

  5. Analysis of Chitin in Contaminated Fuels

    Science.gov (United States)

    1975-09-01

    accomplished by G. Ernst, D. A. Emeric, and S. Levine under the lirection of Emil J. York, Chief, Materials Engineering Div;-on, Laboratory 4000...JSAMERDC. Technical contribution was made by Vincent J. Bagdon, Materials Engi- ieering Division. CONTENTS Section Title Page PREFACE iii I INTRODUCTION...However, chitin can be determined when mycelium is present. In order to hasten the appearance of the mycelium in the fuel if spores are present, sterile

  6. First evidence of the presence of chitin in skeletons of marine sponges. Part II. Glass sponges (Hexactinellida: Porifera).

    Science.gov (United States)

    Ehrlich, Hermann; Krautter, Manfred; Hanke, Thomas; Simon, Paul; Knieb, Christiane; Heinemann, Sascha; Worch, Hartmut

    2007-07-15

    Sponges (Porifera) are presently gaining increased scientific attention because of their secondary metabolites and specific skeleton structures. In contrast to demosponges, whose skeletons are formed from biopolymer spongin, glass sponges (hexactinellids) possess silica-organic composites as the main natural material for their skeletal fibres. Chitin has a crystalline structure and it constitutes a network of organized fibres. This structure confers rigidity and resistance to organisms that contain it, including monocellular (yeast, amoeba, diatoms) and multicellular (higher fungi, arthropods, nematodes, molluscs) organisms. In contrast to different marine invertebrates whose exoskeletons are built of chitin, this polysaccharide has not been found previously as an endogenous biopolymer within glass sponges (Hexactinellida). We hypothesized that glass sponges, which are considered to be the most basal lineage of multicellular animals, must possess chitin. Here, we present a detailed study of the structural and physico-chemical properties of skeletal fragments of the glass sponge Farrea occa. We show that these fibres have a layered design with specific compositional variations in the chitin/silica composite. We applied an effective approach for the demineralization of glass sponge skeletal formations based on an etching procedure using alkali solutions. The results show unambiguously that alpha-chitin is an essential component of the skeletal structures of Hexactinellida. This is the first report of a silica-chitin's composite biomaterial found in nature. From this perspective, the view that silica-chitin scaffolds may be key templates for skeleton formation also in ancestral unicellular organisms, rather than silica-protein composites, emerges as a viable alternative hypothesis.

  7. 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.

  8. 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

    2015-09-10

    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. The Synthesis of the Locating Substitution Derivatives of Chitosan by Click Reaction at the 6-Position of Chitin

    Directory of Open Access Journals (Sweden)

    Yu Chen

    2015-01-01

    Full Text Available A novel method to prepare the macrocyclic compound locating substitution derivatives of chitosan was investigated, by using cyclodextrin as the model of macrocyclic compound. The method combines the advantages of activated 6-OH of chitin and high efficiency of click reaction. Chitin C6-OH p-toluenesulfonate (CTN-6-OTs was generated and subsequently transferred to chitin C6-N3 via nucleophilic substitution. Afterwards, β-cyclodextrin was immobilized at 6-OH of chitin via click reaction to afford CTN-6-CD. Ultimately, CTS-6-CD was obtained by removing the acetyl group of chitin unit. The structures and properties of these products were characterized by FTIR, TG, and XRD, respectively. It was found that CTN-6-CD synthesized at the optimum conditions has an immobilized loading of 1.6126×10-4 mol/g and that of the corresponding CTS-6-CD, generated by removal of the acetyl group, was 1.6891×10-4 mol/g.

  10. Extraction and Characterization of Chitin from Nigerian Sources

    Directory of Open Access Journals (Sweden)

    Muhammed Tijani ISA

    2012-11-01

    Full Text Available The extraction and characterization of chitin from four sources of Nigerian origin was investigated. Chemical demineralization and deproteinization was done to obtain the chitin. Proximate analysis, XRD and SEM analysis were conducted on obtained chitins. The investigation revealed that the shrimp had the highest yield of chitin of 8.15%, crab, crayfish and periwinkle had yields of 7.8%, 2.88% and 0.44% respectively. The proximate analysis showed that chitin from shrimp had highest moisture and protein content of 8.70% and 4.16% respectively. Crayfish had the highest ash and fiber content of 7.20% and 6.98% respectively. Crab has the highest lipid content of 1.70%. The SEM analysis showed very uniform structure with a lamellar organization and less dense structure for chitin from shrimp and the surface of chitin from crayfish consists of fibers that form parallel thread networks. XRD analysis showed that chitin from shrimp was more crystalline than others.

  11. Thermal decomposition of natural polysaccharides: Chitin and chitosan

    Directory of Open Access Journals (Sweden)

    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

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

    Directory of Open Access Journals (Sweden)

    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.

  13. 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.

  14. 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.

  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. First report on chitinous holdfast in sponges (Porifera).

    Science.gov (United States)

    Ehrlich, Hermann; Kaluzhnaya, Oksana V; Tsurkan, Mikhail V; Ereskovsky, Alexander; Tabachnick, Konstantin R; Ilan, Micha; Stelling, Allison; Galli, Roberta; Petrova, Olga V; Nekipelov, Serguei V; Sivkov, Victor N; Vyalikh, Denis; Born, René; Behm, Thomas; Ehrlich, Andre; Chernogor, Lubov I; Belikov, Sergei; Janussen, Dorte; Bazhenov, Vasilii V; Wörheide, Gert

    2013-07-07

    A holdfast is a root- or basal plate-like structure of principal importance that anchors aquatic sessile organisms, including sponges, to hard substrates. There is to date little information about the nature and origin of sponges' holdfasts in both marine and freshwater environments. This work, to our knowledge, demonstrates for the first time that chitin is an important structural component within holdfasts of the endemic freshwater demosponge Lubomirskia baicalensis. Using a variety of techniques (near-edge X-ray absorption fine structure, Raman, electrospray ionization mas spectrometry, Morgan-Elson assay and Calcofluor White staining), we show that chitin from the sponge holdfast is much closer to α-chitin than to β-chitin. Most of the three-dimensional fibrous skeleton of this sponge consists of spicule-containing proteinaceous spongin. Intriguingly, the chitinous holdfast is not spongin-based, and is ontogenetically the oldest part of the sponge body. Sequencing revealed the presence of four previously undescribed genes encoding chitin synthases in the L. baicalensis sponge. This discovery of chitin within freshwater sponge holdfasts highlights the novel and specific functions of this biopolymer within these ancient sessile invertebrates.

  17. 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...

  18. HDACiDB: a database for histone deacetylase inhibitors

    Directory of Open Access Journals (Sweden)

    Murugan K

    2015-04-01

    Full Text Available Kasi Murugan,1 Shanmugasamy Sangeetha,2 Shanmugasamy Ranjitha,2 Antony Vimala,2 Saleh Al-Sohaibani,1 Gopal Rameshkumar21Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, Saudi Arabia; 2Bioinformatics Laboratory, Anna University K. Balachander Research Centre, MIT Campus of Anna University Chennai, Chennai, IndiaAbstract: An histone deacetylase (HDAC inhibitor database (HDACiDB was constructed to enable rapid access to data relevant to the development of epigenetic modulators (HDAC inhibitors [HDACi], helping bring precision cancer medicine a step closer. Thousands of HDACi targeting HDACs are in various stages of development and are being tested in clinical trials as monotherapy and in combination with other cancer agents. Despite the abundance of HDACi, information resources are limited. Tools for in silico experiments on specific HDACi prediction, for designing and analyzing the generated data, as well as custom-made specific tools and interactive databases, are needed. We have developed an HDACiDB that is a composite collection of HDACi and currently comprises 1,445 chemical compounds, including 419 natural and 1,026 synthetic ones having the potential to inhibit histone deacetylation. Most importantly, it will allow application of Lipinski’s rule of five drug-likeness and other physicochemical property-based screening of the inhibitors. It also provides easy access to information on their source of origin, molecular properties, drug likeness, as well as bioavailability with relevant references cited. Being the first comprehensive database on HDACi that contains all known natural and synthetic HDACi, the HDACiDB may help to improve our knowledge concerning the mechanisms of actions of available HDACi and enable us to selectively target individual HDAC isoforms and establish a new paradigm for intelligent epigenetic cancer drug design. The database is freely available on the http

  19. 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.

  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. 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.

  2. Chitin elicitation of natural product production in marine bacteria

    DEFF Research Database (Denmark)

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

    indicating that andrimid serves a function while growing on chitin-containing surfaces. In contrast, a Photobacterium halotolerans sustained production of all metabolites including the antibiotic holomycin. Furthermore, chitin stimulated the production of two potentially novel metabolites not observed...... 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......-negative bacteria (mainly Pseudoalteromonas and Vibrio), we found that some strains were capable of producing antibacterial compounds when grown on chitin, an N-acetyl-D-glucosamine polymer found in the exoskeleton of zooplankton.2 A strain of Vibrio coralliilyticus solely produced the antibiotic andrimid,3...

  3. 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.

  4. Protective Effect of Chitin Urocanate Nanofibers against Ultraviolet Radiation

    Directory of Open Access Journals (Sweden)

    Ikuko Ito

    2015-12-01

    Full Text Available Urocanic acid is a major ultraviolet (UV-absorbing chromophore. Chitins are highly crystalline structures that are found predominantly in crustacean shells. Alpha-chitin consists of microfibers that contain nanofibrils embedded in a protein matrix. Acid hydrolysis is a common method used to prepare chitin nanofibrils (NFs. We typically obtain NFs by hydrolyzing chitin with acetic acid. However, in the present study, we used urocanic acid to prepare urocanic acid chitin NFs (UNFs and examined its protective effect against UVB radiation. Hos: HR-1 mice coated with UNFs were UVB irradiated (302 nm, 150 mJ/cm2, and these mice showed markedly lower UVB radiation-induced cutaneous erythema than the control. Additionally, sunburn cells were rarely detected in the epidermis of UNFs-coated mice after UVB irradiation. Although the difference was not as significant as UNFs, the number of sunburn cells in mice treated with acetic acid chitin nanofibrils (ANFs tended to be lower than in control mice. These results demonstrate that ANFs have a protective effect against UVB and suggest that the anti-inflammatory and antioxidant effects of NFs influence the protective effect of ANFs against UVB radiation. The combination of NFs with other substances that possess UV-protective effects, such as urocanic acid, may provide an enhanced protective effect against UVB radiation.

  5. STUDY ADSORPTION DESORPTION OF MANGANESE(II USING IMPREGNATED CHITIN-CELLULOSE AS ADSORBENT

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    Aldes Lesbani

    2015-03-01

    Full Text Available Abstract- Study adsorption desorption of manganese(II using impregnated chitin-cellulose as adsorbent has been carried out. Chitin was extracted from snail shell and cellulose isolated from rice straw. Chitin and cellulose were impregnated using thiourea as impregnant agent. Characterization of chitin and cellulose was performed using FTIR spectroscopy, determination of water content, and ash content, while impregnated chitin-cellulose was characterized using FTIR spectrophotometer and X-Ray diffractometer. The adsorption of Mn(II on impregnated chitin-cellulose was studied through determination of adsorption time and the influence of Mn(II concentration, while desorption was carried out sequentially using various reagents. The results shown that chitin and cellulose from extraction processes are has similar FTIR spectrum compared to chitin and cellulose standard. The FTIR spectrum of impregnated chitin-cellulose shows both vibration of chitin and cellulose appeared and indicated successfully impregnate. These results were also equal to XRD pattern analysis. The water and ash contents of chitin are 0.038% and 0.043 while for cellulose are 0.184% and 0.165%, respectively. The adsorption of Mn(II on chitin and cellulose are quite similar kinetically, while adsorption of Mn(II on impregnated chitin-cellulose is higher at the same time with chitin and cellulose. In the low concentration of Mn(II, adsorption phenomena are similar on chitin, cellulose, and impregnated chitin-cellulose. Desorption process of Mn(II on the adsorbents shows sodium etilenediamine tetra acetate able to desorp Mn(II up to 68% higher than other reagents. Keywords: Manganese(II, Chitin, Cellulose, Impregnated Chitin-Cellulose

  6. Pharmacokinetics, safety and inducible cytokine responses during a phase 1 trial of the oral histone deacetylase inhibitor ITF2357 (givinostat).

    NARCIS (Netherlands)

    Furlan, A.; Monzani, V.; Reznikov, L.L.; Leoni, F.; Fossati, G.; Modena, D.; Mascagni, P.; Dinarello, C.A.

    2011-01-01

    ITF2357 (givinostat) is a histone deacetylase inhibitor with antiinflammatory properties at low nanomolar concentrations. We report here a phase I safety and pharmacokinetics trial in healthy males administered 50, 100, 200, 400 or 600 mg orally. After 50 mg, mean maximal plasma concentrations reach

  7. Preclinical Metabolism and Disposition of SB939 (Pracinostat), an Orally Active Histone Deacetylase Inhibitor, and Prediction of Human Pharmacokinetics

    NARCIS (Netherlands)

    Jayaraman, Ramesh; Reddy, Venkatesh Pilla; Pasha, Mohammed Khalid; Wang, Haishan; Sangthongpitag, Kanda; Yeo, Pauline; Hu, Chang Yong; Wu, Xiaofeng; Xin, Liu; Goh, Evelyn; New, Lee Sun; Ethirajulu, Kantharaj

    2011-01-01

    The preclinical absorption, distribution, metabolism, and excretion (ADME) properties of Pracinostat [(2E)-3-[2-butyl-1-[2-(diethylamino)ethyl]-1H-benzimidazol-5-yl]-N-hydroxyarylamide hydrochloride; SB939], an orally active histone deacetylase inhibitor, were characterized and its human pharmacokin

  8. 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.

  9. 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.

  10. The Metastasis-associated Proteins 1 and 2 Form Distinct Protein Complexes with Histone Deacetylase Activity

    Institute of Scientific and Technical Information of China (English)

    Ya-LiYao; Wcn-MingYang

    2005-01-01

    The metastasis-associated protein MTA1 has been shown to express differentially to high levels in metastatic cells. MTA2, which is homologous to MTA1, is a component of the NURD ATP-dependcnt chromatin remodeling and histone deacetylase complex. Here we report evidence that although both human MTA1 and MTA2 repress transcription specifically, are located in the nucleus, and contain associated histone deacetylase activity, they exist in two biochemically distinct protein complexes and may perform different functions pertaining to tumor metastasis. Specifically, both MTA1 and MTA2 complexes exert histone deacetylase activity. However, the MTA1 complex contained HDAC1/2, RbAp46/48, and MBD3, but not Sin3 or Mi2, two important components of the MTA2 complex. Moreover, the MTA2 complex is similar to the HDAC1 complex, suggesting a housekeeping role of the MTA2 complex. The MTA1 complex could be further separated, resulting in acore MTA1-HDAC complex, showing that the histone deacetylase activity and transcriptional repression activity were integral properties of the MTA1 complex. Finally, MTA1, unlike MTA2, did not interact with the pleotropic transcription factor YY1 or the immunophilin FKBP25. We suggest that MTA1 associates with adifferent set of transcription factors from MTA2 and that this property may contribute to the metastatic potential of cells overexpressing MTA1. We also report the finding of human MTA3, which is highly homologous toboth MTA1 and MTA2. However, MTA3 does not repress transcription to a significant level and appears to have a diffused pattern of subcellular localization, suggesting a biological role distinct from that of the other two MTA proteins.

  11. 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.

  12. Chitin in the silk gland ducts of the spider Nephila edulis and the silkworm Bombyx mori.

    Directory of Open Access Journals (Sweden)

    Gwilym J G Davies

    Full Text Available Here we report the detection and localisation of chitin in the cuticle of the spinning ducts of both the spider Nephila edulis and the silkworm Bombyx mori. Our observations demonstrate that the duct walls of both animals contain chitin notwithstanding totally independent evolutionary pathways of the systems. We conclude that chitin may well be an essential component for the construction of spinning ducts; we further conclude that in both species chitin may indicate the evolutionary origin of the spinning ducts.

  13. Chitin in the silk gland ducts of the spider Nephila edulis and the silkworm Bombyx mori.

    Science.gov (United States)

    Davies, Gwilym J G; Knight, David P; Vollrath, Fritz

    2013-01-01

    Here we report the detection and localisation of chitin in the cuticle of the spinning ducts of both the spider Nephila edulis and the silkworm Bombyx mori. Our observations demonstrate that the duct walls of both animals contain chitin notwithstanding totally independent evolutionary pathways of the systems. We conclude that chitin may well be an essential component for the construction of spinning ducts; we further conclude that in both species chitin may indicate the evolutionary origin of the spinning ducts.

  14. Chitin in the Silk Gland Ducts of the Spider Nephila edulis and the Silkworm Bombyx mori

    OpenAIRE

    Davies, Gwilym J. G.; Knight, David P; Fritz Vollrath

    2013-01-01

    Here we report the detection and localisation of chitin in the cuticle of the spinning ducts of both the spider Nephila edulis and the silkworm Bombyx mori. Our observations demonstrate that the duct walls of both animals contain chitin notwithstanding totally independent evolutionary pathways of the systems. We conclude that chitin may well be an essential component for the construction of spinning ducts; we further conclude that in both species chitin may indicate the evolutionary origin of...

  15. 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.

  16. Preparation and characterization of chitin beads as a wound dressing precursor.

    Science.gov (United States)

    Yusof, N L; Lim, L Y; Khor, E

    2001-01-01

    Chitin was dissolved in N, N-dimethylacetamide/5% lithium chloride (DMAc/5%LiCl) to form a 0.5% chitin solution. Chitin beads were formed by dropping the 0.5% chitin solution into a nonsolvent coagulant, ethanol. The beads were left in ethanol for 24 h to permit hardening, consolidation, and removal of residual DMAc/5%LiCl solvent in order to give spherical chitin beads uniform size distribution. The ethanol-gelled chitin beads had an average diameter of 535 microm. The chitin beads were subsequently activated in 50% (w/v) NaOH solution and reacted with 1.9 M monochloroacetic acid/2-propanol solution to introduce a carboxymethylated surface layer to the chitin beads. The bilayer character of the surface-carboxymethylated chitin (SCM-chitin) beads was verified by Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and confocal microscopy. The bilayered SCM-chitin beads were found to absorb up to 95 times their dry weight of water. These SCM-chitin beads have potential as a component of wound dressings.

  17. Histone Deacetylase Genes in Arabidopsis Development

    Institute of Scientific and Technical Information of China (English)

    Courtney Hollender; Zhongchi Liu

    2008-01-01

    Histone acetylatlon and deacetylation are directly connected with transcriptional activation and silencing in eukaryotas.Gene families for enzymes that accomplish these histone modifications show surprising complexity in domain organization,tissue-specific expression, and function. This review is focused on the family of histone deacetylases (HDACs) that remove the acetyl group from core histone tails, resulting in a "closed" chromatin and transcriptional repression. In Arabidopsis,18 HDAC genes are divided in to three different types - RPD3-1ike, HD-tuin and sirtuin - with two or more members ineach type. The structural feature of each HDAC class, the expression profile of each HDAC gene during development and functional insights of important family members are summarized here. It is clear that HDACs are an important class of global transcriptional regulators that play crucial roles in plant development, defense, and adaptation.

  18. Sirtuin deacetylases in neurodegenerative diseases of aging

    Institute of Scientific and Technical Information of China (English)

    Adrianna Z Herskovits; Leonard Guarente

    2013-01-01

    Sirtuin enzymes are a family of highly conserved protein deacetylases that depend on nicotinamide adenine dinucleotide (NAD+) for their activity.There are seven sirtuins in mammals and these proteins have been linked with caloric restriction and aging by modulating energy metabolism,genomic stability and stress resistance.Sirtuin enzymes are potential therapeutic targets in a variety of human diseases including cancer,diabetes,inflammatory disorders and neurodegenerative disease.Modulation of sirtuin activity has been shown to impact the course of several aggregate-forming neurodegenerative disorders including Alzheimer's disease,Parkinson's disease,Huntington's disease,amyotrophic lateral sclerosis and spinal and bulbar muscular atrophy.Sirtuins can influence the progression of neurodegenerative disorders by modulating transcription factor activity and directly deacetylating proteotoxic species.Here,we describe sirtuin protein targets in several aggregate-forming neurodegenerative diseases and discuss the therapeutic potential of compounds that modulate sirtuin activity in these disorders.

  19. 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.

  20. 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.

  1. Tubulin acetylation promoting potency and absorption efficacy of deacetylase inhibitors

    Science.gov (United States)

    Mangas-Sanjuan, V; Oláh, J; Gonzalez-Alvarez, I; Lehotzky, A; Tőkési, N; Bermejo, M; Ovádi, J

    2015-01-01

    Background and Purpose Histone deacetylase 6 (HDAC6) and silent information regulator 2 (SIRT2) control the dynamics of the microtubule network via their deacetylase activities. Tubulin polymerization promoting protein (TPPP/p25) enhances microtubule acetylation by its direct binding to HDAC6. Our objective was to characterize the multiple interactions of the deacetylases and to establish the inhibitory potency and the pharmacokinetic features of the deacetylase inhibitors, trichostatin A (TSA) and AGK2. Experimental Approach The interactions of deacetylases with tubulin and TPPP/p25 were quantified by elisa using human recombinant proteins. The effect of inhibitors on the tubulin acetylation was established in HeLa cells transfected with pTPPP and CG-4 cells expressing TPPP/p25 endogenously by celisa (elisa on cells), Western blot and immunofluorescence microscopy. The pharmacokinetic features of the inhibitors were evaluated by in situ kinetic modelling of their intestinal transport in rats. Key Results Deacetylases interact with both tubulin and TPPP/p25, notwithstanding piggy-back binding of HDAC6 or SIRT2 to the TPPP/p25-associated tubulin was established. Much higher inhibitory potency for TSA than for AGK2 was detected in both HeLa and CG-4 cells. Pioneer pharmacokinetic studies revealed passive diffusion and diffusion coupled with secretion for TSA and AGK2 respectively. Both inhibitors exhibited greater permeability than some other well-established drugs. Conclusions and Implications TPPP/p25-directed deacetylase inhibition provides mechanisms for the fine control of the dynamics and stability of the microtubule network. Deacetylase inhibitors with chemical structures similar to TSA and AGK2 appear to be excellent candidates for oral drug absorption. PMID:25257800

  2. Fabrication of α-chitin whisker-reinforced poly(vinyl alcohol) nanocomposite nanofibres by electrospinning

    Science.gov (United States)

    Junkasem, Jirawut; Rujiravanit, Ratana; Supaphol, Pitt

    2006-09-01

    The present contribution reports, for the first time, the successful fabrication of α-chitin whisker-reinforced poly(vinyl alcohol) (PVA) nanocomposite nanofibres by electrospinning. The α-chitin whiskers were prepared from α-chitin flakes from shrimp shells by acid hydrolysis. The as-prepared chitin whiskers exhibited lengths in the range 231-969 nm and widths in the range 12-65 nm, with the average length and width being about 549 and 31 nm, respectively. Successful incorporation of the chitin whiskers within the as-spun PVA/chitin whisker nanocomposite nanofibres was verified by infrared spectroscopic and thermogravimetric methods. The incorporation of chitin whiskers within the as-spun nanocomposite fibre mats increased the Young's modulus by about 4-8 times over that of the neat as-spun PVA fibre mat.

  3. Fabrication of {alpha}-chitin whisker-reinforced poly(vinyl alcohol) nanocomposite nanofibres by electrospinning

    Energy Technology Data Exchange (ETDEWEB)

    Junkasem, Jirawut; Rujiravanit, Ratana; Supaphol, Pitt [Technological Center for Electrospun Fibers and the Petroleum and Petrochemical College, Chulalongkorn University, Soi Chula 12, Phyathai Road, Pathumwan, Bangkok 10300 (Thailand)

    2006-09-14

    The present contribution reports, for the first time, the successful fabrication of {alpha}-chitin whisker-reinforced poly(vinyl alcohol) (PVA) nanocomposite nanofibres by electrospinning. The {alpha}-chitin whiskers were prepared from {alpha}-chitin flakes from shrimp shells by acid hydrolysis. The as-prepared chitin whiskers exhibited lengths in the range 231-969 nm and widths in the range 12-65 nm, with the average length and width being about 549 and 31 nm, respectively. Successful incorporation of the chitin whiskers within the as-spun PVA/chitin whisker nanocomposite nanofibres was verified by infrared spectroscopic and thermogravimetric methods. The incorporation of chitin whiskers within the as-spun nanocomposite fibre mats increased the Young's modulus by about 4-8 times over that of the neat as-spun PVA fibre mat.

  4. [Properties of chitinolytic enzymes from the hepatopancreas of the red king crab (Paralithodes camtschaticus)].

    Science.gov (United States)

    Novikov, V Iu; Mukhin, V A; Rysakova, K S

    2007-01-01

    Our study confirms the presence of chitinolytic, chitosanolytic, and deacetylase activities in the hepatopancreas of the red king crab, related to the specific diet of this species. The maximum rate of chitin/chitosan hydrolysis by an enzyme preparation from crab hepatopancreas occurs at 36.5-37.0 degrees C. Two pH optimums have been found for the enzymatic reaction under mildly alkaline and acidic conditions for both exo- and endochitinase activities. The enzyme preparation is most affine to partly deacetylated chitin with an acetylation degree within 40-50%.

  5. Histone deacetylase inhibitors (HDACIs: multitargeted anticancer agents

    Directory of Open Access Journals (Sweden)

    Ververis K

    2013-02-01

    Full Text Available Katherine Ververis,1 Alison Hiong,1 Tom C Karagiannis,1,* Paul V Licciardi2,*1Epigenomic Medicine, Alfred Medical Research and Education Precinct, 2Allergy and Immune Disorders, Murdoch Childrens Research Institute, Melbourne, VIC, Australia*These authors contributed equally to this workAbstract: Histone deacetylase (HDAC inhibitors are an emerging class of therapeutics with potential as anticancer drugs. The rationale for developing HDAC inhibitors (and other chromatin-modifying agents as anticancer therapies arose from the understanding that in addition to genetic mutations, epigenetic changes such as dysregulation of HDAC enzymes can alter phenotype and gene expression, disturb homeostasis, and contribute to neoplastic growth. The family of HDAC inhibitors is large and diverse. It includes a range of naturally occurring and synthetic compounds that differ in terms of structure, function, and specificity. HDAC inhibitors have multiple cell type-specific effects in vitro and in vivo, such as growth arrest, cell differentiation, and apoptosis in malignant cells. HDAC inhibitors have the potential to be used as monotherapies or in combination with other anticancer therapies. Currently, there are two HDAC inhibitors that have received approval from the US FDA for the treatment of cutaneous T-cell lymphoma: vorinostat (suberoylanilide hydroxamic acid, Zolinza and depsipeptide (romidepsin, Istodax. More recently, depsipeptide has also gained FDA approval for the treatment of peripheral T-cell lymphoma. Many more clinical trials assessing the effects of various HDAC inhibitors on hematological and solid malignancies are currently being conducted. Despite the proven anticancer effects of particular HDAC inhibitors against certain cancers, many aspects of HDAC enzymes and HDAC inhibitors are still not fully understood. Increasing our understanding of the effects of HDAC inhibitors, their targets and mechanisms of action will be critical for the

  6. Role of Deacetylase Activity of N-Deacetylase/N-Sulfotransferase 1 in Forming N-Sulfated Domain in Heparan Sulfate.

    Science.gov (United States)

    Dou, Wenfang; Xu, Yongmei; Pagadala, Vijayakanth; Pedersen, Lars C; Liu, Jian

    2015-08-14

    Heparan sulfate (HS) is a highly sulfated polysaccharide that plays important physiological roles. The biosynthesis of HS involves a series of enzymes, including glycosyltransferases (or HS polymerase), epimerase, and sulfotransferases. N-Deacetylase/N-Sulfotransferase isoform 1 (NDST-1) is a critical enzyme in this pathway. NDST-1, a bifunctional enzyme, displays N-deacetylase and N-sulfotransferase activities to convert an N-acetylated glucosamine residue to an N-sulfo glucosamine residue. Here, we report the cooperative effects between N-deacetylase and N-sulfotransferase activities. Using baculovirus expression in insect cells, we obtained three recombinant proteins: full-length NDST-1 and the individual N-deacetylase and N-sulfotransferase domains. Structurally defined oligosaccharide substrates were synthesized to test the substrate specificities of the enzymes. We discovered that N-deacetylation is the limiting step and that interplay between the N-sulfotransferase and N-deacetylase accelerates the reaction. Furthermore, combining the individually expressed N-deacetylase and N-sulfotransferase domains produced different sulfation patterns when compared with that made by the NDST-1 enzyme. Our data demonstrate the essential role of domain cooperation within NDST-1 in producing HS with specific domain structures.

  7. Inhibition of histone deacetylase activity by valproic acid blocks adipogenesis.

    Science.gov (United States)

    Lagace, Diane C; Nachtigal, Mark W

    2004-04-30

    Adipogenesis is dependent on the sequential activation of transcription factors including the CCAAT/enhancer-binding proteins (C/EBP), peroxisome proliferator-activated receptor gamma (PPARgamma), and steroid regulatory element-binding protein (SREBP). We show that the mood stabilizing drug valproic acid (VPA; 0.5-2 mm) inhibits mouse 3T3 L1 and human preadipocyte differentiation, likely through its histone deacetylase (HDAC) inhibitory properties. The HDAC inhibitor trichostatin A (TSA) also inhibited adipogenesis, whereas the VPA analog valpromide, which does not possess HDAC inhibitory effects, did not prevent adipogenesis. Acute or chronic VPA treatment inhibited differentiation yet did not affect mitotic clonal expansion. VPA (1 mm) inhibited PPARgamma induced differentiation but does not activate a PPARgamma reporter gene, suggesting that it is not a PPARgamma ligand. VPA or TSA treatment reduced mRNA and protein levels of PPARgamma and SREBP1a. TSA reduced C/EBPalpha mRNA and protein levels, whereas VPA only produced a decrease in C/EBPalpha protein expression. Overall our results highlight a role for HDAC activity in adipogenesis that can be blocked by treatment with VPA.

  8. 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.

  9. Histone deacetylase complexes promote trinucleotide repeat expansions.

    Directory of Open Access Journals (Sweden)

    Kim Debacker

    2012-02-01

    Full Text Available Expansions of DNA trinucleotide repeats cause at least 17 inherited neurodegenerative diseases, such as Huntington's disease. Expansions can occur at frequencies approaching 100% in affected families and in transgenic mice, suggesting that specific cellular proteins actively promote (favor expansions. The inference is that expansions arise due to the presence of these promoting proteins, not their absence, and that interfering with these proteins can suppress expansions. The goal of this study was to identify novel factors that promote expansions. We discovered that specific histone deacetylase complexes (HDACs promote CTG•CAG repeat expansions in budding yeast and human cells. Mutation or inhibition of yeast Rpd3L or Hda1 suppressed up to 90% of expansions. In cultured human astrocytes, expansions were suppressed by 75% upon inhibition or knockdown of HDAC3, whereas siRNA against the histone acetyltransferases CBP/p300 stimulated expansions. Genetic and molecular analysis both indicated that HDACs act at a distance from the triplet repeat to promote expansions. Expansion assays with nuclease mutants indicated that Sae2 is one of the relevant factors regulated by Rpd3L and Hda1. The causal relationship between HDACs and expansions indicates that HDACs can promote mutagenesis at some DNA sequences. This relationship further implies that HDAC3 inhibitors being tested for relief of expansion-associated gene silencing may also suppress somatic expansions that contribute to disease progression.

  10. Production of N-acetyl-beta-D-glucosamine from chitin by Aeromonas sp. GJ-18 crude enzyme.

    Science.gov (United States)

    Kuk, J H; Jung, W J; Jo, G H; Kim, Y C; Kim, K Y; Park, R D

    2005-08-01

    A bacterium, GJ-18, having strong chitinolytic activity was isolated from coastal soil. The isolated strain was identified as Aeromonas sp. by morphological and biochemical properties along with 16S rRNA gene sequence. The crude chitinolytic activity of culture supernatants was maximal on the 5th day of culture. Below 45 degrees C, chitin was effectively hydrolyzed to N-acetyl-beta-D-glucosamine (GlcNAc) by Aeromonas sp. GJ-18 crude enzymes, but hydrolysis decreased markedly above 50 degrees C. The optimum pH for enzyme activity was 5.0. TLC and HPLC analysis revealed that, below 45 degrees C, the major reaction product was GlcNAc with a small amount of (GlcNAc)(2) and (GlcNAc)(3), whereas above 50 degrees C the major product was (GlcNAc)(2). When swollen chitin (100 mg) was incubated with crude enzyme preparations (10 U) at 40 degrees C, chitin was hydrolyzed to 83.0 and 94.9% yield of GlcNAc within 5 and 9 days, respectively.

  11. Structural alterations, pore generation, and deacetylation of α- and β-chitin submitted to steam explosion.

    Science.gov (United States)

    Tan, Too Shen; Chin, Hui Yen; Tsai, Min-Lang; Liu, Chao-Lin

    2015-05-20

    The purpose of this study was to use an environmentally friendly steam explosion method to achieve α- and β-chitin structural alterations, pore generation, and deacetylation, enhancing the degree of deacetylation (DD) in chitin and extending its applications. The samples of α- and β-chitin possessing various moisture contents that were exploded at 9 kg/cm(2) exhibited higher DDs, lower densities, lower crystallinity and more porous structures compared to unexploded chitin. After explosion, β-chitin exhibited a larger expansion ratio, lower crystallinity and contained a larger proportion of small-sized particles compared to α-chitin. The highest DD values of exploded α- and β-chitin with 75% moisture content were 42.9% and 43.7%, respectively. The exploded chitin samples with lower moisture content exhibited lower DDs, densities, crystallinity indices, smaller particle sizes, and higher expansion ratios than the chitin samples with higher moisture content. The chitin samples with lower moisture content also contained larger and more numerous pores.

  12. Caspofungin Treatment of Aspergillus fumigatus Results in ChsG-Dependent Upregulation of Chitin Synthesis and the Formation of Chitin-Rich Microcolonies.

    Science.gov (United States)

    Walker, Louise A; Lee, Keunsook K; Munro, Carol A; Gow, Neil A R

    2015-10-01

    Treatment of Aspergillus fumigatus with echinocandins such as caspofungin inhibits the synthesis of cell wall β-1,3-glucan, which triggers a compensatory stimulation of chitin synthesis. Activation of chitin synthesis can occur in response to sub-MICs of caspofungin and to CaCl2 and calcofluor white (CFW), agonists of the protein kinase C (PKC), and Ca(2+)-calcineurin signaling pathways. A. fumigatus mutants with the chs gene (encoding chitin synthase) deleted (ΔAfchs) were tested for their response to these agonists to determine the chitin synthase enzymes that were required for the compensatory upregulation of chitin synthesis. Only the ΔAfchsG mutant was hypersensitive to caspofungin, and all other ΔAfchs mutants tested remained capable of increasing their chitin content in response to treatment with CaCl2 and CFW and caspofungin. The resulting increase in cell wall chitin content correlated with reduced susceptibility to caspofungin in the wild type and all ΔAfchs mutants tested, with the exception of the ΔAfchsG mutant, which remained sensitive to caspofungin. In vitro exposure to the chitin synthase inhibitor, nikkomycin Z, along with caspofungin demonstrated synergistic efficacy that was again AfChsG dependent. Dynamic imaging using microfluidic perfusion chambers demonstrated that treatment with sub-MIC caspofungin resulted initially in hyphal tip lysis. However, thickened hyphae emerged that formed aberrant microcolonies in the continued presence of caspofungin. In addition, intrahyphal hyphae were formed in response to echinocandin treatment. These in vitro data demonstrate that A. fumigatus has the potential to survive echinocandin treatment in vivo by AfChsG-dependent upregulation of chitin synthesis. Chitin-rich cells may, therefore, persist in human tissues and act as the focus for breakthrough infections.

  13. Antihepatotoxic effect of isolated chitin from Rhizopus oryzae against paracetamol-induced hepatotoxicity

    Directory of Open Access Journals (Sweden)

    Akila Ramanathan

    2011-03-01

    Full Text Available The present study was aimed at investigating the antihepatotoxic activity of isolated fungal chitin, a natural polysaccharide from Rhizopus oryzae NCIM1009 against paracetamol-induced toxicity in rats. Changes in the levels of biochemical markers of hepatic injury such as serum glutamate oxaloacetic transaminase (SGOT, serum glutamic pyuruvic transaminase (SGPT, alkaline phosphatase, bilirubin and total protein were determined in both treated and control group of rats. The effect of fungal chitin was compared with that of silymarin (25 mg/kg. The results showed that paracetamol (750 mg/kg elevated the levels of biomarkers enzymes. Treatment with fungal chitin (200 mg/kg brought the marker level near to normal and showed significant hepatoprotective activity. Acute toxicity studies of fungal chitin was carried out and found safe up to 2,000 mg/kg. The isolated fungal chitin was characterized by IR spectroscopy and compared with commercial chitin.

  14. 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.

  15. 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.

  16. FONCTIONS UBIQUITINE-DEPENDANTES DE LA DEACETYLASE HDAC6

    OpenAIRE

    Boyault, Cyril

    2006-01-01

    At the start of my Ph.D., the lab had discovered and characterized HDAC6, an unusual deacetylase that possesses two deacetylase domains and directly binds to ubiquitin. Moreover, the lab had found that HDAC6 interacts with UFD3/PLAP, a regulator of ubiquitin turnover, and VCP, a mouse homologue of the chaperone Cdc48. However, nothing was known about HDAC6 biological function, especially its role in the ubiquitination pathway. We first observed that HDAC6 over-expression slows down the degrad...

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

    OpenAIRE

    Ali Reza Khosravi; David J Erle

    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 ...

  18. Biotechnological process of chitin recovery from shrimp waste using Lactobacillus plantarum NCDN4

    OpenAIRE

    Le, Thanh Ha; Nguyen, Thi Ha

    2015-01-01

    Chitin in shrimp waste is tightly associated with proteins, lipids, pigments and mineral deposits. Therefore, these source materials have to be pretreated to remove these components. For a long time, chemical process has been used widely for extraction of chitin from shrimp waste. The chemical process however led to severe environmental damage and low chitin quality. The biological process has been shown promising to replace the harsh chemical process to reduce the environment impact. In our ...

  19. 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.

  20. 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 ...

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

    Directory of Open Access Journals (Sweden)

    Anna eIlnicka

    2015-03-01

    Full Text Available 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 template during carbonization of wood and chitin. It is suggested why particular components and derivatives of wood and chitin (cellulose and chitosan can not form porous carbonaceous matrixes when are carbonized separately.

  2. The influence of chitin synthesis inhibitors on growth of entomopathogenic fungi in vitro

    Directory of Open Access Journals (Sweden)

    Anna Sapieha

    2014-08-01

    Full Text Available Beauveria bassiana, Paecilomyces farinosus, Verticillium lecanii, Conidiobolus thnmboides, Erynia pieris, E. radicans were examined on medium to which were added three chitin synthesis inhibitors.

  3. 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.

  4. 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.

  5. Effect of Inula viscosa extract on chitin synthesis in dermatophytes and Candida albicans.

    Science.gov (United States)

    Maoz, M; Neeman, I

    2000-08-01

    An antimycotic effect of an extract from Inula viscosa leaves was demonstrated affecting chitin synthesis in dermatophytes and Candida albicans. The antimycotic effect was compared to the effect caused by miconazole nitrate--an antifungal drug. The inhibition effect on chitin synthesis was not correlated to the extent of growth inhibition caused by the antifungal agents: both miconazole nitrate and the I. viscosa extract inhibited the growth of dermatophytes and C. albicans. Miconazole nitrate did not affect chitin synthesis--except for M. canis--whereas I. viscosa extract caused a significant decline in chitin content.

  6. Elevated chitin content reduces the susceptibility of Candida species to caspofungin.

    Science.gov (United States)

    Walker, Louise A; Gow, Neil A R; Munro, Carol A

    2013-01-01

    The echinocandin antifungal drugs inhibit synthesis of the major fungal cell wall polysaccharide β(1,3)-glucan. Echinocandins have good efficacy against Candida albicans but reduced activity against other Candida species, in particular Candida parapsilosis and Candida guilliermondii. Treatment of Candida albicans with a sub-MIC level of caspofungin has been reported to cause a compensatory increase in chitin content and to select for sporadic echinocandin-resistant FKS1 point mutants that also have elevated cell wall chitin. Here we show that elevated chitin in response to caspofungin is a common response in various Candida species. Activation of chitin synthesis was observed in isolates of C. albicans, Candida tropicalis, C. parapsilosis, and C. guilliermondii and in some isolates of Candida krusei in response to caspofungin treatment. However, Candida glabrata isolates demonstrated no exposure-induced change in chitin content. Furthermore, isolates of C. albicans, C. krusei, C. parapsilosis, and C. guilliermondii which were stimulated to have higher chitin levels via activation of the calcineurin and protein kinase C (PKC) signaling pathways had reduced susceptibility to caspofungin. Isolates containing point mutations in the FKS1 gene generally had higher chitin levels and did not demonstrate a further compensatory increase in chitin content in response to caspofungin treatment. These results highlight the potential of increased chitin synthesis as a potential mechanism of tolerance to caspofungin for the major pathogenic Candida species.

  7. 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.

  8. Prominent reinforcing effect of chitin nanocrystals on electrospun polydioxanone nanocomposite fiber mats.

    Science.gov (United States)

    Zhu, Lei; Liang, Kai; Ji, Yali

    2015-04-01

    The ultra-strong nanocomposite fiber mats based on biodegradable polydioxanone (PDO) and chitin nanocrystals (ChiNCs) were successfully prepared by means of electrospinning. The ChiNCs are uniformly dispersed in the PDO matrix and mostly oriented along fiber long axis, resulting in a significant improvement in mechanical property. Moreover, the introduction of ChiNCs led to the increase of the glass-transition temperature (Tg) and thermal decomposition temperature (Td) of PDO elucidated by thermal analyses. In addition, the loading of ChiNCs caused very different In vitro degradation behavior compared to neat PDO fiber mat. Furthermore, in vitro cell culture results indicated that the addition of ChiNCs improved the cellular adhesion and proliferation.

  9. Biological Chitin-MOF Composites with Hierarchical Pore Systems for Air-Filtration Applications.

    Science.gov (United States)

    Wisser, Dorothea; Wisser, Florian M; Raschke, Silvia; Klein, Nicole; Leistner, Matthias; Grothe, Julia; Brunner, Eike; Kaskel, Stefan

    2015-10-19

    Metal-organic frameworks (MOFs) are promising materials for gas-separation and air-filtration applications. However, for these applications, MOF crystallites need to be incorporated in robust and manageable support materials. We used chitin-based networks from a marine sponge as a non-toxic, biodegradable, and low-weight support material for MOF deposition. The structural properties of the material favor predominant nucleation of the MOF crystallites at the inside of the hollow fibers. This composite has a hierarchical pore system with surface areas up to 800 m(2)  g(-1) and pore volumes of 3.6 cm(3)  g(-1) , allowing good transport kinetics and a very high loading of the active material. Ammonia break-through experiments highlight the accessibility of the MOF crystallites and the adsorption potential of the composite indicating their high potential for filtration applications for toxic industrial gases.

  10. Natural and Synthetic Macrocyclic Inhibitors of the Histone Deacetylase Enzymes

    DEFF Research Database (Denmark)

    Maolanon, Alex; Kristensen, Helle; Leman, Luke;

    2016-01-01

    Inhibition of histone deacetylase (HDAC) enzymes has emerged as a target for development of cancer chemotherapy. Four compounds have gained approval for clinical use by the Food and Drug Administration (FDA) in the US, and several are currently in clinical trials. However, none of these compounds...

  11. Innovative Strategies for Selective Inhibition of Histone Deacetylases

    DEFF Research Database (Denmark)

    Maolanon, Alex Ramalak; Madsen, Andreas Stahl; Olsen, Christian Adam

    2016-01-01

    Histone deacetylases (HDAC) are a family of closely related enzymes involved in epigenetic and posttranscriptional regulation of numerous genes and proteins. Their deregulation is associated with a number of diseases, and a handful of HDAC inhibitors have been approved for cancer treatment. None...

  12. Preparation of Size-Controlled Silver Nanoparticles and Chitin-Based Composites and Their Antimicrobial Activities

    Directory of Open Access Journals (Sweden)

    Vinh Quang Nguyen

    2013-01-01

    Full Text Available A simple method for the preparation of size-controlled spherical silver nanoparticles (Ag NPs was reported for their generation by autoclaving a mixture of silver-containing glass powder and glucose. The particle size is regulated by the glucose concentration, with concentrations of 0.25, 1.0, and 4.0 wt% glucose providing small (3.48±1.83 nm in diameter, medium (6.53±1.78 nm, and large (12.9±2.5 nm particles, respectively. In this study, Ag NP/chitin composites were synthesized by mixing each of these three Ag NP suspensions with a <5% deacetylated (DAc chitin powder (pH 7.0 at room temperature. The Ag NPs were homogenously dispersed and stably adsorbed onto the chitin. The Ag NP/chitin composites were obtained as yellow or brown powders. Approximately 5, 15, and 20 μg of the small, medium, and large Ag NPs, respectively, were estimated to maximally adsorb onto 1 mg of chitin. The bactericidal and antifungal activities of the Ag NP/chitin composites increased as the amount of Ag NPs in the chitin increased. Furthermore, smaller Ag NPs (per weight in the chitin composites provided higher bactericidal and anti-fungal activities.

  13. Hydrophobic modification on surface of chitin sponges for highly effective separation of oil.

    Science.gov (United States)

    Duan, Bo; Gao, Huimin; He, Meng; Zhang, Lina

    2014-11-26

    A highly hydrophobic and oleophilic chitin sponge was synthesized, for the first time, via a freeze-dried method and then by using a thermal chemical vapor deposition of methyltrichlorosilane (MTCS) at different relative humidity. Fourier-transform infrared, energy-dispersive X-ray spectra, and scanning electron microscopy confirmed that the silanization occurred on the pore wall surface of the chitin sponge. The MTCS-coated chitin sponge had interconnected open-cell structures with the average pore size from 20 to 50 μm, and the MTCS nanofilaments immobilized on the chitin matrix, leading to the high hydrophobicity, as a result of the existence of a solid/air composite rough surface. Cyclic compression test indicated that the hydrophobic chitin sponges exhibited excellent elasticity and high mechanical durability. The sponges could efficiently collect organics both on the surface and bottom from the water with the highest 58 times of their own weight absorption capacities through the combination of the particular wettability and great porosity. Furthermore, the biodegradation kinetics of the chitin sponge forecasted that the chitin could be completely biodegraded within 32 days by the microorganisms in the soil. This work provided a new pathway to prepare the chitin-based materials for highly effective removal of oil from water, showing potential application in the pollutant remediation field.

  14. 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.

  15. 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.

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

    Science.gov (United States)

    Kielak, Anna M; Cretoiu, Mariana Silvia; Semenov, Alexander V; Sørensen, Søren J; van Elsas, Jan Dirk

    2013-01-01

    Chitin amendment is a promising soil management strategy that may enhance the suppressiveness of soil toward plant pathogens. However, we understand very little of the effects of added chitin, including the putative successions that take place in the degradative process. We performed an experiment 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 chiA 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 understanding of the response of the soil bacterial communities to chitin and are of use for both the understanding of soil suppressiveness and the possible mining of soil for novel enzymes.

  17. Fabrication of free-standing replicas of fragile, laminar, chitinous biotemplates.

    Science.gov (United States)

    Lakhtakia, Akhlesh; Martín-Palma, Raúl J; Motyka, Michael A; Pantano, Carlo G

    2009-09-01

    The conformal-evaporated-film-by-rotation technique, followed by the dissolution of chitin in an aqueous solution of orthophosphoric acid, can be used to fabricate free-standing replicas of fragile, laminar, chitinous biotemplates. This novel approach was demonstrated using butterfly wings as biotemplates and GeSeSb chalcogenide glass for replicas.

  18. 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

  19. Comparative modeling and benchmarking data sets for human histone deacetylases and sirtuin families.

    Science.gov (United States)

    Xia, Jie; Tilahun, Ermias Lemma; Kebede, Eyob Hailu; Reid, Terry-Elinor; Zhang, Liangren; Wang, Xiang Simon

    2015-02-23

    Histone deacetylases (HDACs) are an important class of drug targets for the treatment of cancers, neurodegenerative diseases, and other types of diseases. Virtual screening (VS) has become fairly effective approaches for drug discovery of novel and highly selective histone deacetylase inhibitors (HDACIs). To facilitate the process, we constructed maximal unbiased benchmarking data sets for HDACs (MUBD-HDACs) using our recently published methods that were originally developed for building unbiased benchmarking sets for ligand-based virtual screening (LBVS). The MUBD-HDACs cover all four classes including Class III (Sirtuins family) and 14 HDAC isoforms, composed of 631 inhibitors and 24609 unbiased decoys. Its ligand sets have been validated extensively as chemically diverse, while the decoy sets were shown to be property-matching with ligands and maximal unbiased in terms of "artificial enrichment" and "analogue bias". We also conducted comparative studies with DUD-E and DEKOIS 2.0 sets against HDAC2 and HDAC8 targets and demonstrate that our MUBD-HDACs are unique in that they can be applied unbiasedly to both LBVS and SBVS approaches. In addition, we defined a novel metric, i.e. NLBScore, to detect the "2D bias" and "LBVS favorable" effect within the benchmarking sets. In summary, MUBD-HDACs are the only comprehensive and maximal-unbiased benchmark data sets for HDACs (including Sirtuins) that are available so far. MUBD-HDACs are freely available at http://www.xswlab.org/ .

  20. 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......Vibrio coralliilyticus is a putative coral pathogen in tropical oceans, but also possesses antagonistic traits. We previously reported antibacterial activity in Vibrio coralliilyticus strain S2052 based upon the antibiotic andrimid. The purpose of the present study was to determine whether V....... coralliilyticus S2052 produces the antibiotic under conditions mimicking natural habitats of vibrios. S2052 synthesized andrimid with both chitin and macroalgal extracts as sole nutrient source. With chitin, the biosynthesis of metabolites other than andrimid was largely abolished, and the yield of the antibiotic...

  1. Squid Pen Chitin Chitooligomers as Food Colorants Absorbers

    OpenAIRE

    Tzu-Wen Liang; Chih-Ting Huang; Nguyen Anh Dzung; San-Lang Wang

    2015-01-01

    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 ...

  2. Quorum sensing-regulated chitin metabolism provides grazing resistance to Vibrio cholerae biofilms.

    Science.gov (United States)

    Sun, Shuyang; Tay, Qi Xiang Martin; Kjelleberg, Staffan; Rice, Scott A; McDougald, Diane

    2015-08-01

    Association of Vibrio cholerae with chitinous surfaces of zooplankton is important for its persistence in marine environments, as it provides accessibility to nutrients and resistance to stresses. Predation by heterotrophic protists has a major impact on the survival of V. cholerae. V. cholerae forms biofilms as its main defensive strategy, and quorum sensing (QS) additionally regulates the production of antiprotozoal factors. The role of chitin and QS regulation in V. cholerae grazing resistance was investigated by exposing V. cholerae wild-type (WT) and QS mutant biofilms grown on chitin flakes to the bacteriotrophic, surface-feeding flagellate Rhynchomonas nasuta. V. cholerae formed more biofilm biomass on chitin flakes compared with nonchitinous surfaces. The growth of R. nasuta was inhibited by WT biofilms grown on chitin flakes, whereas the inhibition was attenuated in QS mutant biofilms. The chitin-dependent toxicity was also observed when the V. cholerae biofilms were developed under continuous flow or grown on a natural chitin source, the exoskeleton of Artemia. In addition, the antiprotozoal activity and ammonium concentration of V. cholerae biofilm supernatants were quantified. The ammonium levels (3.5 mM) detected in the supernatants of V. cholerae WT biofilms grown on chitin flakes were estimated to reduce the number of R. nasuta by >80% in add-back experiments, and the supernatant of QS mutant biofilms was less toxic owing to a decrease in ammonium production. Transcriptomic analysis revealed that the majority of genes involved in chitin metabolism and chemotaxis were significantly downregulated in QS mutant biofilms when grown on chitin compared with the WT biofilms.

  3. Microbial responses to chitin and chitosan in oxic and anoxic agricultural soil slurries

    Science.gov (United States)

    Wieczorek, A. S.; Hetz, S. A.; Kolb, S.

    2014-06-01

    Microbial degradation of chitin in soil substantially contributes to carbon cycling in terrestrial ecosystems. Chitin is globally the second most abundant biopolymer after cellulose and can be deacetylated to chitosan or can be hydrolyzed to N,N'-diacetylchitobiose and oligomers of N-acetylglucosamine by aerobic and anaerobic microorganisms. Which pathway of chitin hydrolysis is preferred by soil microbial communities is unknown. Supplementation of chitin stimulated microbial activity under oxic and anoxic conditions in agricultural soil slurries, whereas chitosan had no effect. Thus, the soil microbial community likely was more adapted to chitin as a substrate. In addition, this finding suggested that direct hydrolysis of chitin was preferred to the pathway that starts with deacetylation. Chitin was apparently degraded by aerobic respiration, ammonification, and nitrification to carbon dioxide and nitrate under oxic conditions. When oxygen was absent, fermentation products (acetate, butyrate, propionate, hydrogen, and carbon dioxide) and ammonia were detected, suggesting that butyric and propionic acid fermentation, along with ammonification, were likely responsible for anaerobic chitin degradation. In total, 42 different chiA genotypes were detected of which twenty were novel at an amino acid sequence dissimilarity of less than 50%. Various chiA genotypes responded to chitin supplementation and affiliated with a novel deep-branching bacterial chiA genotype (anoxic conditions), genotypes of Beta- and Gammaproteobacteria (oxic and anoxic conditions), and Planctomycetes (oxic conditions). Thus, this study provides evidence that detected chitinolytic bacteria were catabolically diverse and occupied different ecological niches with regard to oxygen availability enabling chitin degradation under various redox conditions on community level.

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

    Science.gov (United States)

    Farnesi, Luana C; Brito, José M; Linss, Jutta G; Pelajo-Machado, Marcelo; Valle, Denise; Rezende, Gustavo L

    2012-01-01

    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 on Ae

  5. 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

  6. 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.

  7. Purification of a chitin-binding protein from Moringa oleifera seeds with potential to relieve pain and inflammation.

    Science.gov (United States)

    Pereira, Mirella Leite; de Oliveira, Hermogenes David; de Oliveira, Jose Tadeu Abreu; Gifoni, Juliana Menezes; Rocha, Raquel de Oliveira; de Sousa, Daniele de Oliveira Bezerra; Vasconcelos, Ilka Maria

    2011-11-01

    Moringa oleifera Lam. is a perennial multipurpose tree that has been successfully used in folk medicine to cure several inflammatory processes. The aim of this study was to purify and characterize a chitin-binding protein from Moringa oleifera seeds, named Mo-CBP4, and evaluate its antinociceptive and anti-inflammatory effects in vivo. The protein was purified by affinity chromatography on chitin followed by ion exchange chromatography. Acetic acid-induced abdominal constrictions assay was used for the antinociceptive and anti-inflammatory activity assessments. Mo-CBP4 is a glycoprotein (2.9% neutral carbohydrate) composed of two protein subunits with apparent molecular masses of 28 and 18 kDa (9 kDa in the presence of reducing agent). The intraperitoneal injection of Mo-CBP4 (3.5 and 10 mg/kg) into mice 30 min before acetic acid administration potently and significantly reduced the occurrence of abdominal writhing in a dose dependent manner by 44.7% and 100%, respectively. In addition, the oral administration of the protein (10 mg/kg) resulted in 18% and 52.8% reductions in abdominal writhing when given 30 and 60 min prior to acetic acid administration, respectively. Mo-CBP4, when administered by intraperitoneal route, also caused a significant and dose-dependent inhibition of peritoneal capillary permeability induced by acid acetic and significantly inhibited leukocyte accumulation in the peritoneal cavity. In conclusion, this pioneering study describes that the chitin-binding protein Mo-CBP4, from M. oleifera seeds, exhibits anti-inflammatory and antinociceptive properties and scientifically supports the use of this multipurpose tree in folk medicine.

  8. [Prospects of application of the chitin-binding domains to isolation and purification of recombinant proteins by affinity chromatography: a review].

    Science.gov (United States)

    Kurek, D V; Lopatin, S A; Varlamov, V P

    2009-01-01

    Properties of substrate-binding domains, some parameters of affinity sorbents, and a number of other special features that were necessary to take into account during creation of chromatographic system for isolation and purification of proteins with incorporated chitin-binding domain were discussed in this review. This method was shown to be successfully used along with metal-chelate affinity chromatography. The metal-chelate affinity chromatography with the use of polyhistidine peptides as affinity labels is successfully applied to isolation, purification, and investigation of recombinant proteins. However, this system had some disadvantages. At present, scientists attracted more and more attention to substrate-binding domains, including those chitin-binding, because they had a number of advantages being used as affinity label.

  9. 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.

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

    Science.gov (United States)

    Berger, Lúcia Raquel Ramos; Stamford, Thayza Christina Montenegro; Stamford-Arnaud, Thatiana Montenegro; de Alcântara, Sergio Roberto Cabral; da Silva, Antonio Cardoso; da Silva, Adamares Marques; do Nascimento, Aline Elesbão; de Campos-Takaki, Galba Maria

    2014-01-01

    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. PMID:24853288

  11. 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.

  12. pH敏感性羟乙基甲壳素/聚丙烯酸水凝胶的制备及其释药性能研究%Study on Preparation of the pH Sensitive Hydroxyethyl Chitin/Poly(Acrylic Acid) Hydrogel and Its Drug Release Property

    Institute of Scientific and Technical Information of China (English)

    赵育; 陈国华; 孙明昆; 晋治涛; 高从堦

    2006-01-01

    用氯乙醇对甲壳素进行醚化改性,得到水溶性羟乙基甲壳素(Hydroxyethyl chitin, HECH),用化学交联法制备了由聚丙烯酸(PAA)和HECH复合的互穿网络(IPN)水凝胶.溶胀实验表明:该水凝胶在人工肠液(pH7.4,I=0.1)中的溶胀度远大于在人工胃液(pH1.4,I=0.1)中的溶胀度, 凝胶的溶胀度随着温度的升高而增大;以该凝胶制备了双氯芬酸钾缓释体系,释放实验表明该凝胶具有较好的缓释性能.

  13. 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.

  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

    During normal cooking of meat, a class of mutagenic/carcinogenic compounds called heterocyclic amines is formed. Heterocyclic amines are rapidly absorbed and metabolised in the human body, and for estimation of the intake of heterocyclic amines, it is useful to determinate their levels in the urine....... 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. Discovery of 505-million-year old chitin in the basal demosponge Vauxia gracilenta.

    Science.gov (United States)

    Ehrlich, H; Rigby, J Keith; Botting, J P; Tsurkan, M V; Werner, C; Schwille, P; Petrášek, Z; Pisera, A; Simon, P; Sivkov, V N; Vyalikh, D V; Molodtsov, S L; Kurek, D; Kammer, M; Hunoldt, S; Born, R; Stawski, D; Steinhof, A; Bazhenov, V V; Geisler, T

    2013-12-13

    Sponges are probably the earliest branching animals, and their fossil record dates back to the Precambrian. Identifying their skeletal structure and composition is thus a crucial step in improving our understanding of the early evolution of metazoans. Here, we present the discovery of 505-million-year-old chitin, found in exceptionally well preserved Vauxia gracilenta sponges from the Middle Cambrian Burgess Shale. Our new findings indicate that, given the right fossilization conditions, chitin is stable for much longer than previously suspected. The preservation of chitin in these fossils opens new avenues for research into other ancient fossil groups.

  16. 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

    in the lungs, measured as the total cell efflux in BAL, EPO and chitinase production. However, chitin enhanced the total IgE, specific IgE and specific IgG1 production as efficiently as alum. Pre-treatment with chitin but not with alum depressed the concentration of the Th2 cytokines IL-4 and IL-13 in BAL...... fluid. These results shows that chitin, in spite of a reduction of the Th2 cytokine levels in the lungs, enhanced the total and specific IgE production in A. fumigatus culture filtrate induced allergy....

  17. Insecticidal benzoylphenyl ureas: structure-activity relationships as chitin synthesis inhibitors.

    Science.gov (United States)

    Hajjar, N P; Casida, J E

    1978-06-30

    The 1-benzoyl-3-phenylurea insecticide diflubenzuron is a potent inhibitor for the conversion of (14)C-labeled glucose to (14)C-labeled chitin in isolated abdomens of newly emerged adult milkweed bugs (Oncopeltus fasciatus Dallas). The inhibitory activity of 24 diflubenzuron analogs in this in vitro chitin-synthesizing system is in good agreement with their toxicity to fifth instar nymphs of this species. These insecticides act quickly and directly within the integument to ultimately block the terminal polymerization step in chitin formation.

  18. 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.

  19. 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

  20. 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

  1. 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.

  2. 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.

  3. Purification of a novel chitin-binding lectin with antimicrobial and antibiofilm activities from a bangladeshi cultivar of potato (Solanum tuberosum).

    Science.gov (United States)

    Hasan, Imtiaj; Ozeki, Yasuhiro; Kabir, Syed Rashel

    2014-04-01

    A new chitin-binding lectin was purified from a Bangladeshi cultivar 'Deshi' of potato (Solanum tuberosum L.) through anion-exchange and affinity chromatographies using a chitin column. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) showed the molecular mass of the lectin as 20,000 Daltons. This molecular mass was almost half of the molecular masses of chitin-binding lectins derived from other potatoes. The lectin showed both bactericidal and growth-inhibiting activities against Gram-positive (Listeria monocytogenes) and Gram-negative (Escherichia coli, Salmonella enteritidis and Shigella boydii) pathogenic bacteria. It also showed antifungal activity against Rhizopus spp., Penicillium spp. and Aspergillus niger. Biofilm produced by the bacterium Pseudomonas aeruginosa was dose-dependently reduced by 5-20% in 24 h after administration of the lectin, which was attributed to the glycan-binding property of the lectin having affinity to GlcNAc polymers. It was the first observation that any potato lectin prevented biofilm formation by P. aeruginosa and, therefore, could have possible applications in clinical microbiology and biomedical science.

  4. 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

  5. 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

  6. The new low-toxic histone deacetylase inhibitor S-(2) induces apoptosis in various acute myeloid leukaemia cells

    OpenAIRE

    2012-01-01

    Abstract Histone deacetylase inhibitors (HDACi) induce tumour cell cycle arrest and/or apoptosis, and some of them are currently used in cancer therapy. Recently, we described a series of powerful HDACi characterized by a 1,4-benzodiazepine (BDZ) ring hybridized with a linear alkyl chain bearing a hydroxamate function as Zn++-chelating group. Here, we explored the anti-leukaemic properties of three novel hybrids, namely the chiral compounds (S)-2 and (R)-2, and their non-chiral analogue 4, wh...

  7. 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.

  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. 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.

  10. 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.

  11. 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.

  12. Chitin Extraction from Crustacean Shells Using Biological Methods – A Review

    Directory of Open Access Journals (Sweden)

    Wassila Arbia

    2013-01-01

    Full Text Available After cellulose, chitin is the most widespread biopolymer in nature. Chitin and its derivatives have great economic value because of their biological activities and their industrial and biomedical applications. It can be extracted from three sources, namely crustaceans, insects and microorganisms. However, the main commercial sources of chitin are shells of crustaceans such as shrimps, crabs, lobsters and krill that are supplied in large quantities by the shellfish processing industries. Extraction of chitin involves two steps, demineralisation and deproteinisation, which can be conducted by two methods, chemical or biological. The chemical method requires the use of acids and bases, while the biological method involves microorganisms. Although lactic acid bacteria are mainly applied, other microbial species including proteolytic bacteria have also been successfully implemented, as well as mixed cultures involving lactic acid-producing bacteria and proteolytic microorganisms. The produced lactic acid allows shell demineralisation, since lactic acid reacts with calcium carbonate, the main mineral component, to form calcium lactate.

  13. Morphology engineering of Penicillium chrysogenum by RNA silencing of chitin synthase gene.

    Science.gov (United States)

    Liu, Hui; Wang, Peng; Gong, Guohong; Wang, Li; Zhao, Genhai; Zheng, Zhiming

    2013-03-01

    Chitin synthases, that catalyze the formation of chitin the major component of cell walls in most filamentous fungi, play crucial roles in the growth and morphogenesis. To investigate the roles of chitin synthase in Penicillium chrysogenum, we developed an RNAi system to silence the class III chitin synthase gene chs4. After transformation, mutants had a slow growth rate and shorter but highly branched hyphae. All transformants either were unable to form conidia or could form only a few. Changes in chs4 expression could lead to a completely different morphology and eventually cause distinct penicillin yields. In particular, the yield of one transformant was 41 % higher than that of the original strain.

  14. Sericin-binded-deprotenized natural rubber film containing chitin whiskers as elasto-gel dressing.

    Science.gov (United States)

    Watthanaphanit, Anyarat; Rujiravanit, Ratana

    2017-03-18

    Here, we aims to demonstrate a simple concept in biomaterials design by using natural resources solely as raw materials to fabricate elastic wound care dressing. Elasto-gel films comprise of silk sericin (SRC), natural rubber (NR), and chitin whisker (CTW) were developed. A glue-like protein SRC found in silk cocoons is beneficial for the treatment of wounds due to its superior skin moisturizing ability. However, the pure SRC film is generally difficult to be fabricated because of its weak structural feature. This limitation was overcome by using NR as a binder which consecutively rendered elasticity and strength of the films. CTW was chosen as another component to promote ability of the films for tissue restoration. Before the film formation, protein in the natural rubber latex (NRL) was removed to avoid allergic and cytotoxic problems. The enzyme-treated NR/SRC (ETNR/SRC) films having different blend compositions were fabricated by solution casting technique. The highest amount of the SRC to gain an easy to handle ETNR/SRC film was 30%. The ETNR/SRC/CTW films having 20% SRC were fabricated and studied in comparison. Essential properties of the films as elastic wound care dressings were investigated and effect of the materials chemistry on the observed properties were discussed.

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

    Science.gov (United States)

    Khosravi, Ali Reza; 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.

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

    Directory of Open Access Journals (Sweden)

    Ali Reza Khosravi

    Full Text Available 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

  17. 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.

  18. Effect of Chitin Extraction Processes on Residual Antimicrobials in Shrimp Shells

    OpenAIRE

    2012-01-01

    The present study examined the influences of industrial chitin extraction processes on the residual oxytetracycline (OTC) and oxolinic acid (OA) in shrimp carapaces and shells. The drugs were orally administered by catheter to the kuruma shrimp (Penaeus japonicus) and vannamei shrimp (Penaeus vannamei). The shrimps were sampled at 6-h post-dosing and their carapaces and shells were collected and used as raw material in the chitin extraction. Residua...

  19. Growth on Chitin Impacts the Transcriptome and Metabolite Profiles of Antibiotic-Producing Vibrio coralliilyticus S2052 and Photobacterium galatheae S2753

    DEFF Research Database (Denmark)

    Giubergia, Sonia; Phippen, Christopher; Nielsen, Kristian Fog;

    2017-01-01

    Members of the Vibrionaceae family are often associated with chitin-containing organisms, and they are thought to play a major role in chitin degradation. The purpose of the present study was to determine how chitin affects the transcriptome and metabolome of two bioactive Vibrionaceae strains, V....... We observed a strong increase in production of secondary metabolites, suggesting an ecological role for these molecules during chitin colonization in the marine environment....... and that their secondary metabolites likely play a crucial role during chitin colonization. IMPORTANCE The bacterial family Vibrionaceae (vibrios) is considered a major player in the degradation of chitin, the most abundant polymer in the marine environment; however, the majority of studies on the topic have focused......, Vibrio coralliilyticus and Photobacterium galatheae. We focused on chitin degradation genes and secondary metabolites based on the assumption that these molecules in nature confer an advantage to the producer. Growth on chitin caused upregulation of genes related to chitin metabolism and of genes...

  20. Histone deacetylase inhibitors induced differentiation and accelerated mineralization of pulp-derived cells.

    LENUS (Irish Health Repository)

    Duncan, Henry F

    2012-03-01

    Histone deacetylase inhibitors (HDACis) alter the homeostatic balance between 2 groups of cellular enzymes, histone deacetylases (HDACs) and histone acetyltransferases (HATs), increasing transcription and influencing cell behavior. This study investigated the potential of 2 HDACis, valproic acid (VPA) and trichostatin A (TSA), to promote reparative processes in pulp cells as assayed by viability, cell cycle, and mineralization analyses.

  1. Macrocyclic Peptoid–Peptide Hybrids as Inhibitors of Class I Histone Deacetylases

    DEFF Research Database (Denmark)

    Olsen, Christian Adam; Montero, Ana; Leman, Luke J.;

    2012-01-01

    We report the design, synthesis, and biological evaluation of the first macrocyclic peptoid-containing histone deacetylase (HDAC) inhibitors. The compounds selectively inhibit human class I HDAC isoforms in vitro, with no inhibition of the tubulin deacetylase activity associated with class IIb HD...

  2. A non-isotopic assay for histone deacetylase activity.

    Science.gov (United States)

    Hoffmann, K; Brosch, G; Loidl, P; Jung, M

    1999-05-01

    Inhibitors of histone deacetylase (HD) bear great potential as new drugs due to their ability to modulate transcription and to induce apoptosis or differentiation in cancer cells. To study the activity of HD and the effect of potential inhibitors in vitro so far only radio-active assays have existed. For the search of new inhibitors and for the use in HD identification and purification we established a simple, non-radioactive assay that allows screening of large numbers of compounds. The assay is based on an aminocoumarin derivative of an Omega-acetylated lysine as enzyme substrate.

  3. 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.

  4. 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.

  5. 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.

  6. 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

    Background: FIBCD1 is a type II transmembrane protein located on the brush border of intestinal epithelial cells. FIBCD1 binds specifically to acetylated compounds such as chitin through the C-terminal fibrinogen-related domain. Chitin is a highly acetylated homopolymeric b-1,4-N-acetylglucosamine ......Background: FIBCD1 is a type II transmembrane protein located on the brush border of intestinal epithelial cells. FIBCD1 binds specifically to acetylated compounds such as chitin through the C-terminal fibrinogen-related domain. Chitin is a highly acetylated homopolymeric b-1,4-N......-acetylglucosamine carbohydrate, which next to cellulose is the most abundant biopolymer found in nature, eg in fungi and parasites. It was recently demonstrated that chitin induces the accumulation in tissue of IL-4-expressing innate immune cells in vivo and it was suggested that chitin thus could be a recognition element...... of NF-jB signalling and downstream synthesis of mucosal epithelial-derived cytokines, TSLP and IL-33, which shapes the local accumulation and activation of Th2 responses. Results: Initial experiments have focused on the establishment of stable FIBCD1 overexpression in HEK293, HCT-116 and A549 epithelial...

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

    DEFF Research Database (Denmark)

    Laroche, Fabrice Jean Francois

    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...... 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...

  8. Histone deacetylase inhibitors: pharmacotherapeutic implications as epigenetic modifier

    Directory of Open Access Journals (Sweden)

    Pinki Vishwakarma

    2014-02-01

    Full Text Available Epigenetic modifications such as acetylation and deacetylation of histone proteins play a decisive role in transcriptional alteration and expression of genes. Acetylation is catalysed by the histone acetyl transferases enzymes and activates expression of genes by converting chromatin into a less compact, transcriptionally active state. Histone deacetylases enzymes catalyze deacetylation that condenses chromatin into a closed structure .Consequently transcriptional factors are unable to access DNA and gene expression is suppressed. Balanced activity of HATs and HDACS is essential for normal gene expression. Increased HDAC activity can lead to imbalance in protein acetylation resulting in hypoacetylation, tight chromatin structure and suppression of various genes. This aberrant suppression of genes is the hallmark of several malignant and other diseases including neurodegenerative disorders. Histone Deacetylase Inhibitors (HDACIs have potential to restore the balance of histone acetylation that reverses the silencing of pathological genes. Thus HDACIs modify expression of genes without affecting sequence of DNA and act as epigenetic modifiers. Vorinostat and romidepsin are FDA approved HDACIs. Valproic acid, belinostat and many others are in different phases of clinical trials. This review article explores the target based epigenetic mechanisms as well as existing and potential therapeutic role of HDACIs in various malignant and non-malignant diseases. Data sources were articles published in medical journals and bibliographic database Medline. [Int J Basic Clin Pharmacol 2014; 3(1.000: 27-36

  9. Three-dimensional chitin-based scaffolds from Verongida sponges (Demospongiae: Porifera). Part II: Biomimetic potential and applications.

    Science.gov (United States)

    Ehrlich, H; Steck, E; Ilan, M; Maldonado, M; Muricy, G; Bavestrello, G; Kljajic, Z; Carballo, J L; Schiaparelli, S; Ereskovsky, A; Schupp, P; Born, R; Worch, H; Bazhenov, V V; Kurek, D; Varlamov, V; Vyalikh, D; Kummer, K; Sivkov, V V; Molodtsov, S L; Meissner, H; Richter, G; Hunoldt, S; Kammer, M; Paasch, S; Krasokhin, V; Patzke, G; Brunner, E; Richter, W

    2010-08-01

    In order to evaluate the biomedical potential of three-dimensional chitinous scaffolds of poriferan origin, chondrocyte culturing experiments were performed. It was shown for the first time that freshly isolated chondrocytes attached well to the chitin scaffold and synthesized an extracellular matrix similar to that found in other cartilage tissue engineering constructs. Chitin scaffolds also supported deposition of a proteoglycan-rich extracellular matrix of chondrocytes seeded bioconstructs in an in vivo environment. We suggest that chitin sponge scaffolds, apart from the demonstrated biomedical applications, are highly optimized structures for use as filtering systems, templates for biomineralization as well as metallization in order to produce catalysts.

  10. H3K9me-independent gene silencing in fission yeast heterochromatin by Clr5 and histone deacetylases.

    Science.gov (United States)

    Hansen, Klavs R; Hazan, Idit; Shanker, Sreenath; Watt, Stephen; Verhein-Hansen, Janne; Bähler, Jürg; Martienssen, Robert A; Partridge, Janet F; Cohen, Amikam; Thon, Geneviève

    2011-01-06

    Nucleosomes in heterochromatic regions bear histone modifications that distinguish them from euchromatic nucleosomes. Among those, histone H3 lysine 9 methylation (H3K9me) and hypoacetylation have been evolutionarily conserved and are found in both multicellular eukaryotes and single-cell model organisms such as fission yeast. In spite of numerous studies, the relative contributions of the various heterochromatic histone marks to the properties of heterochromatin remain largely undefined. Here, we report that silencing of the fission yeast mating-type cassettes, which are located in a well-characterized heterochromatic region, is hardly affected in cells lacking the H3K9 methyltransferase Clr4. We document the existence of a pathway parallel to H3K9me ensuring gene repression in the absence of Clr4 and identify a silencing factor central to this pathway, Clr5. We find that Clr5 controls gene expression at multiple chromosomal locations in addition to affecting the mating-type region. The histone deacetylase Clr6 acts in the same pathway as Clr5, at least for its effects in the mating-type region, and on a subset of other targets, notably a region recently found to be prone to neo-centromere formation. The genomic targets of Clr5 also include Ste11, a master regulator of sexual differentiation. Hence Clr5, like the multi-functional Atf1 transcription factor which also modulates chromatin structure in the mating-type region, controls sexual differentiation and genome integrity at several levels. Globally, our results point to histone deacetylases as prominent repressors of gene expression in fission yeast heterochromatin. These deacetylases can act in concert with, or independently of, the widely studied H3K9me mark to influence gene silencing at heterochromatic loci.

  11. H3K9me-independent gene silencing in fission yeast heterochromatin by Clr5 and histone deacetylases.

    Directory of Open Access Journals (Sweden)

    Klavs R Hansen

    Full Text Available Nucleosomes in heterochromatic regions bear histone modifications that distinguish them from euchromatic nucleosomes. Among those, histone H3 lysine 9 methylation (H3K9me and hypoacetylation have been evolutionarily conserved and are found in both multicellular eukaryotes and single-cell model organisms such as fission yeast. In spite of numerous studies, the relative contributions of the various heterochromatic histone marks to the properties of heterochromatin remain largely undefined. Here, we report that silencing of the fission yeast mating-type cassettes, which are located in a well-characterized heterochromatic region, is hardly affected in cells lacking the H3K9 methyltransferase Clr4. We document the existence of a pathway parallel to H3K9me ensuring gene repression in the absence of Clr4 and identify a silencing factor central to this pathway, Clr5. We find that Clr5 controls gene expression at multiple chromosomal locations in addition to affecting the mating-type region. The histone deacetylase Clr6 acts in the same pathway as Clr5, at least for its effects in the mating-type region, and on a subset of other targets, notably a region recently found to be prone to neo-centromere formation. The genomic targets of Clr5 also include Ste11, a master regulator of sexual differentiation. Hence Clr5, like the multi-functional Atf1 transcription factor which also modulates chromatin structure in the mating-type region, controls sexual differentiation and genome integrity at several levels. Globally, our results point to histone deacetylases as prominent repressors of gene expression in fission yeast heterochromatin. These deacetylases can act in concert with, or independently of, the widely studied H3K9me mark to influence gene silencing at heterochromatic loci.

  12. 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.

  13. Multifunctional chitin nanogels for simultaneous drug delivery, bioimaging, and biosensing.

    Science.gov (United States)

    Rejinold N, Sanoj; Chennazhi, Krishna Prasad; Tamura, Hiroshi; Nair, Shantikumar V; Rangasamy, Jayakumar

    2011-09-01

    In this work, we developed biodegradable chitin nanogels (CNGs) by controlled regeneration method. For multifunctionalization, we have conjugated CNGs with MPA-capped-CdTe-QDs (QD-CNGs) for the in vitro cellular localization studies. In addition, the Bovine Serum Albumin (BSA) was loaded on to QD-CNGs (BSA-QD-CNGs). The CNGs, QD-CNGs, and BSA-QD-CNGs were well-characterized by SEM and AFM, which shows that the nanogels are in the range of Cyclic Voltametry. The cytocompatibility assay showed that the nanogels are nontoxic to L929, NIH-3T3, KB, MCF-7, PC3, and VERO cells. The cell uptake studies of the QD-CNGs were analyzed, which showed retention of these nanogels inside the cells (L929, PC3, and VERO). In addition, the protein loading efficiency of the nano gels has also been analyzed. Our preliminary studies reveal that these multifunctionalized nanogels could be useful for drug delivery with simultaneous imaging and biosensing.

  14. 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.

  15. Squid pen chitin chitooligomers as food colorants absorbers.

    Science.gov (United States)

    Liang, Tzu-Wen; Huang, Chih-Ting; Dzung, Nguyen Anh; Wang, San-Lang

    2015-01-20

    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.

  16. 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.

  17. 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...

  18. Revisit of alpha-chitin crystal structure using high resolution X-ray diffraction data.

    Science.gov (United States)

    Sikorski, Pawel; Hori, Ritsuko; Wada, Masahisa

    2009-05-11

    High resolution synchrotron X-ray fiber diffraction data recorded from crab tendon chitin have been used to describe the crystal structure of alpha-chitin. Crystal structures at 100 and 300 K have been solved using restrained crystallographic refinement against diffraction intensities measured from the fiber diffraction patterns. The unit cell contains two polymer chains in a 2(1) helix conformation and in the antiparallel orientation. The best agreement between predicated and observed X-ray diffraction intensities is obtained for a model that includes two distinctive conformations of C6-O6 hydroxymethl group. Those conformations are different from what is proposed in the generally accepted alpha-chitin crystal structure (J. Mol. Biol. 1978, 120, 167-181). Based on refined positions of the O6 atoms, a network of hydrogen bonds involving O6 is proposed. This network of hydrogen bonds can explain the main features of the polarized FTIR spectra of alpha-chitin and sheds some light on the origin of splitting of the amide I band observed on alpha-chitin IR spectra.

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

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    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.

  20. Histone deacetylase inhibition as an alternative strategy against invasive aspergillosis

    Directory of Open Access Journals (Sweden)

    Frederic eLamoth

    2015-02-01

    Full Text Available Invasive aspergillosis (IA is a life-threatening infection due to Aspergillus fumigatus and other Aspergillus spp. Drugs targeting the fungal cell membrane (triazoles, amphotericin B or cell wall (echinocandins are currently the sole therapeutic options against IA. Their limited efficacy and the emergence of resistance warrant the identification of new antifungal targets. Histone deacetylases (HDACs are enzymes responsible of the deacetylation of lysine residues of core histones, thus controlling chromatin remodeling and transcriptional activation. HDACs also control the acetylation and activation status of multiple non-histone proteins, including the heat shock protein 90 (Hsp90, an essential molecular chaperone for fungal virulence and antifungal resistance. This review provides an overview of the different HDACs in Aspergillus spp. as well as their respective contribution to total HDAC activity, fungal growth, stress responses, and virulence. The potential of HDAC inhibitors, currently under development for cancer therapy, as novel alternative antifungal agents against IA is discussed.

  1. Inhibition of histone deacetylases sensitizes glioblastoma cells to lomustine

    DEFF Research Database (Denmark)

    Staberg, Mikkel; Michaelsen, Signe Regner; Rasmussen, Rikke Darling;

    2017-01-01

    deacetylase (HDAC) expression levels were determined using quantitative real-time PCR and Western blotting. The efficacy of either CCNU alone or its combination with TSA was assessed using various assays, i.e., cell viability assays (MTT), cell cycle assays (flow cytometry, FACS), double-strand DNA break (DSB......) quantification assays (microscopy/immunofluorescence) and expression profiling assays of proteins involved in apoptosis and cell stress (Western blotting and protein array). RESULTS: We found that the HDAC1, 3 and 6 expression levels were significantly increased in GBM samples compared to non-neoplastic brain...... control samples. Additionally, we found that pre-treatment of GBM cells with TSA resulted in an enhancement of their sensitivity to CCNU, possibly via the accumulation of DSBs, decreased cell proliferation and viability rates, and an increased apoptotic rate. CONCLUSION: From our data we conclude...

  2. 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

  3. First evidence of chitin as a component of the skeletal fibers of marine sponges. Part I. Verongidae (demospongia: Porifera).

    Science.gov (United States)

    Ehrlich, Hermann; Maldonado, Manuel; Spindler, Klaus-Dieter; Eckert, Carsten; Hanke, Thomas; Born, René; Goebel, Caren; Simon, Paul; Heinemann, Sascha; Worch, Hartmut

    2007-07-15

    The Porifera (sponges) are often regarded as the oldest, extant metazoan phylum, also bearing the ancestral stage for most features occurring in higher animals. The absence of chitin in sponges, except for the wall of peculiar resistance bodies produced by a highly derived fresh-water group, is puzzling, since it points out chitin to be an autapomorphy for a particular sponge family rather than the ancestral condition within the metazoan lineage. By investigating the internal proteinaceous (spongin) skeleton of two demosponges (Aplysina sp. and Verongula gigantea) using a wide array of techniques (Fourier transform infrared (FTIR), Raman, X-ray, Calcofluor White Staining, Immunolabeling, and chitinase test), we show that chitin is a component of the outermost layer (cuticle) of the skeletal fibers of these demosponges. FTIR and Raman spectra, as well as X-ray difractograms consistently revealed that sponge chitin is much closer to the alpha-chitin known from other animals than to beta-chitin. These findings support the view that the occurrence of a chitin-producing system is the ancestral condition in Metazoa, and that the alpha-chitin is the primitive form in animals.

  4. 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.

  5. Comparison of chitin and Amberlite IRA-938 for alpha-galactosidase immobilization.

    Science.gov (United States)

    Onal, Seçil; Telefoncu, Azmi

    2003-02-01

    Watermelon alpha-galactosidase (EC 3.2.1.22) was immobilized on a natural (chitin) and a synthetic anion-exchange (Amberlite IRA-938) support by covalent coupling methods. The procedure entails the activation of supports with 1,1'-carbonyldiimidazole (CDI), followed by immobilization of the enzyme on to these supports without and with a spacer arm; gamma-aminobutyric acid (GABA). Optimization of activation was performed by changing the CDI concentrations and coupling efficiencies. The comparison of two immobilization techniques for both chitin and Amberlite IRA-938 was made by comparing different enzyme concentrations against enzyme activity yield. Furthermore, the storage stability of the immobilized enzymes was also investigated and chitin immobilized alpha-galactosidase was found to be better. Although the activity yield of immobilized enzymes were the same for both supports, the short storage stability of immobilized enzyme on Amberlite IRA-938 is currently a drawback to its applications.

  6. The chitin-binding capability of Cy-AMP1 from cycad is essential to antifungal activity.

    Science.gov (United States)

    Yokoyama, Seiya; Iida, Yuto; Kawasaki, Yousuke; Minami, Yuji; Watanabe, Keiichi; Yagi, Fumio

    2009-07-01

    Antimicrobial peptides are important components of the host innate immune responses by exerting broad-spectrum microbicidal activity against pathogenic microbes. Cy-AMP1 found in the cycad (Cycas revoluta) seeds has chitin-binding ability, and the chitin-binding domain was conserved in knottin-type and hevein-type antimicrobial peptides. The recombinant Cy-AMP1 was expressed in Escherichia coli and purified to study the role of chitin-binding domain. The mutants of Cy-AMP1 lost chitin-binding ability completely, and its antifungal activity was markedly decreased in comparison with native Cy-AMP1. However, the antimicrobial activities of the mutant peptides are nearly identical to that of native one. It was suggested that the chitin-binding domain plays an essential role in antifungal, but not antimicrobial, activity of Cy-AMP1.

  7. Deacetylase inhibitors as a novel modality in the treatment of multiple myeloma.

    Science.gov (United States)

    Richardson, Paul G; Moreau, Philippe; Laubach, Jacob P; Maglio, Michelle E; Lonial, Sagar; San-Miguel, Jesus

    2017-03-01

    Deacetylase enzymes remove acetyl groups from histone and nonhistone proteins. Dysregulation of deacetylase activity is a hallmark of malignancy, including multiple myeloma (MM). Deacetylase inhibitors (DACi) cause epigenetic modification and inhibition of the aggresome pathway, resulting in death of MM cells. Panobinostat, a pan-DACi, has shown significant clinical benefit and is the first DACi approved for the treatment of MM. It is approved for use in combination with bortezomib and dexamethasone for the treatment of patients with relapsed or relapsed and refractory MM who have received ≥2 prior regimens including bortezomib and an immunomodulatory drug. Ricolinostat and ACY-241, which selectively inhibit HDAC6 and the aggresome pathway, are currently being studied in combination with dexamethasone and bortezomib or an immunomodulatory drug for the treatment of relapsed and refractory MM. In this review, we discuss the data from key clinical trials investigating deacetylase inhibitors as novel treatment options for MM.

  8. Characterization of a midgut-specific chitin synthase gene (LmCHS2) responsible for biosynthesis of chitin of peritrophic matrix in Locusta migratoria.

    Science.gov (United States)

    Liu, Xiaojian; Zhang, Huanhuan; Li, Sheng; Zhu, Kun Yan; Ma, Enbo; Zhang, Jianzhen

    2012-12-01

    Chitin, an essential component of peritrophic matrix (PM), is produced by a series of biochemical reactions. Chitin synthase plays a crucial role in chitin polymerization in chitin biosynthetic pathway. In this study, we identified and characterized a full-length cDNA of chitin synthase 2 gene (LmCHS2) from Locusta migratoria. The cDNA contains an open reading frame of 4569 nucleotides that encode 1523 amino acid residues, and 76- and 373-nucleotides for 5'- and 3'-noncoding regions, respectively. Analysis of LmCHS2 transcript in different tissues of the locust by using real-time quantitative PCR indicated that LmCHS2 was exclusively expressed in midgut and gastric caeca (a part of the midgut). The highest expression was found in the anterior midgut with a decline of the transcript level from the anterior to posterior regions. During growth and development of locusts, there was only a slight expression in eggs, but the expression gradually increased from nymphs to adults. In situ hybridization further revealed that LmCHS2 transcript mainly presented in the apical regions of brush border forming columnar cells of gastric caeca. LmCHS2 dsRNA was injected to fifth-instar nymphs to further explore biological functions of LmCHS2. Significantly down-regulated transcript of LmCHS2 resulted in a cessation of feeding and a high mortality of the insect. However, no visible abnormal morphological change of locusts was observed until insects molted to adults. After dissection, we found that the average length of midguts from the LmCHS2 dsRNA-injected locusts was shorter than that of the control insects that were injected with dsGFP. Furthermore, microsection of midguts showed that the PM of the LmCHS2 dsRNA-injected nymphs was amorphous and thin as compared with the controls. Our results demonstrate that LmCHS2 is responsible for the biosynthesis of chitin associated with PM and plays an essential role in locust growth and development.

  9. 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.

  10. Chitin recognition via chitotriosidase promotes pathologic type-2 helper T cell responses to cryptococcal infection.

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    Darin L Wiesner

    2015-03-01

    Full Text Available Pulmonary mycoses are often associated with type-2 helper T (Th2 cell responses. However, mechanisms of Th2 cell accumulation are multifactorial and incompletely known. To investigate Th2 cell responses to pulmonary fungal infection, we developed a peptide-MHCII tetramer to track antigen-specific CD4+ T cells produced in response to infection with the fungal pathogen Cryptococcus neoformans. We noted massive accruement of pathologic cryptococcal antigen-specific Th2 cells in the lungs following infection that was coordinated by lung-resident CD11b+ IRF4-dependent conventional dendritic cells. Other researchers have demonstrated that this dendritic cell subset is also capable of priming protective Th17 cell responses to another pulmonary fungal infection, Aspergillus fumigatus. Thus, higher order detection of specific features of fungal infection by these dendritic cells must direct Th2 cell lineage commitment. Since chitin-containing parasites commonly elicit Th2 responses, we hypothesized that recognition of fungal chitin is an important determinant of Th2 cell-mediated mycosis. Using C. neoformans mutants or purified chitin, we found that chitin abundance impacted Th2 cell accumulation and disease. Importantly, we determined Th2 cell induction depended on cleavage of chitin via the mammalian chitinase, chitotriosidase, an enzyme that was also prevalent in humans experiencing overt cryptococcosis. The data presented herein offers a new perspective on fungal disease susceptibility, whereby chitin recognition via chitotriosidase leads to the initiation of harmful Th2 cell differentiation by CD11b+ conventional dendritic cells in response to pulmonary fungal infection.

  11. 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.

  12. 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.

  13. Treatment of chitin-producing wastewater by micro-electrolysis-contact oxidization

    Institute of Scientific and Technical Information of China (English)

    杨岳平; 徐新华; 陈海峰

    2004-01-01

    The technique of micro-electrolysis-contact oxidization was exploited to treat chitin-producing wastewater.Results showed that Fe-C micro-electrolysis can remove about 30% CODcr, raise pH from 0.7 to 5.5.The CODcr removal efficiency by biochemical process can be more than 80%. During a half year's operation,the whole system worked very stably and had good results, as proved by the fact that every quality indicator of effluent met the expected discharge standards; which means that chitin wastewater can be treated by the technique of micro-electrolysis, contact oxidization.

  14. Treatment of chitin-producing wastewater by micro-electrolysis-contact oxidization

    Institute of Scientific and Technical Information of China (English)

    杨岳平; 徐新华; 陈海峰

    2004-01-01

    The technique of micro-electrolysis-contact oxidization was exploited to treat chitin-producing wastewater. Results showed that Fe-C micro-electrolysis can remove about 30% CODcr, raise pH from 0.7 to 5.5. The CODcr removal efficiency by biochemical process can be more than 80%. During a half year's operation, the whole system worked very stably and had good results, as proved by the fact that every quality indicator of effluent met the expected discharge standards; which means that chitin wastewater can be treated by the technique of micro-electrolysis, contact oxidization.

  15. Growth on Chitin Impacts the Transcriptome and Metabolite Profiles of Antibiotic-Producing Vibrio coralliilyticus S2052 and Photobacterium galatheae S2753

    Science.gov (United States)

    Phippen, Christopher; Nielsen, Kristian Fog

    2017-01-01

    ABSTRACT Members of the Vibrionaceae family are often associated with chitin-containing organisms, and they are thought to play a major role in chitin degradation. The purpose of the present study was to determine how chitin affects the transcriptome and metabolome of two bioactive Vibrionaceae strains, Vibrio coralliilyticus and Photobacterium galatheae. We focused on chitin degradation genes and secondary metabolites based on the assumption that these molecules in nature confer an advantage to the producer. Growth on chitin caused upregulation of genes related to chitin metabolism and of genes potentially involved in host colonization and/or infection. The expression of genes involved in secondary metabolism was also significantly affected by growth on chitin, in one case being 34-fold upregulated. This was reflected in the metabolome, where the antibiotics andrimid and holomycin were produced in larger amounts on chitin. Other polyketide synthase/ nonribosomal peptide synthetase (PKS-NRPS) clusters in P. galatheae were also strongly upregulated on chitin. Collectively, this suggests that both V. coralliilyticus and P. galatheae have a specific lifestyle for growth on chitin and that their secondary metabolites likely play a crucial role during chitin colonization. IMPORTANCE The bacterial family Vibrionaceae (vibrios) is considered a major player in the degradation of chitin, the most abundant polymer in the marine environment; however, the majority of studies on the topic have focused on a small number of Vibrio species. In this study, we analyzed the genomes of two vibrios to assess their genetic potential for the degradation of chitin. We then used transcriptomics and metabolomics to demonstrate that chitin strongly affects these vibrios at both the transcriptional and metabolic levels. We observed a strong increase in production of secondary metabolites, suggesting an ecological role for these molecules during chitin colonization in the marine environment

  16. 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.)

  17. 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.

  18. Chitin synthases with a myosin motor-like domain control the resistance of Aspergillus fumigatus to echinocandins.

    Science.gov (United States)

    Jiménez-Ortigosa, Cristina; Aimanianda, Vishukumar; Muszkieta, Laetitia; Mouyna, Isabelle; Alsteens, David; Pire, Stéphane; Beau, Remi; Krappmann, Sven; Beauvais, Anne; Dufrêne, Yves F; Roncero, César; Latgé, Jean-Paul

    2012-12-01

    Aspergillus fumigatus has two chitin synthases (CSMA and CSMB) with a myosin motor-like domain (MMD) arranged in a head-to-head configuration. To understand the function of these chitin synthases, single and double csm mutant strains were constructed and analyzed. Although there was a slight reduction in mycelial growth of the mutants, the total chitin synthase activity and the cell wall chitin content were similar in the mycelium of all of the mutants and the parental strain. In the conidia, chitin content in the ΔcsmA strain cell wall was less than half the amount found in the parental strain. In contrast, the ΔcsmB mutant strain and, unexpectedly, the ΔcsmA/ΔcsmB mutant strain did not show any modification of chitin content in their conidial cell walls. In contrast to the hydrophobic conidia of the parental strain, conidia of all of the csm mutants were hydrophilic due to the presence of an amorphous material covering the hydrophobic surface-rodlet layer. The deletion of CSM genes also resulted in an increased susceptibility of resting and germinating conidia to echinocandins. These results show that the deletion of the CSMA and CSMB genes induced a significant disorganization of the cell wall structure, even though they contribute only weakly to the overall cell wall chitin synthesis.

  19. Characterization of organics consistent with β-chitin preserved in the Late Eocene cuttlefish Mississaepia mississippiensis.

    Directory of Open Access Journals (Sweden)

    Patricia G Weaver

    Full Text Available BACKGROUND: Preservation of original organic components in fossils across geological time is controversial, but the potential such molecules have for elucidating evolutionary processes and phylogenetic relationships is invaluable. Chitin is one such molecule. Ancient chitin has been recovered from both terrestrial and marine arthropods, but prior to this study had not been recovered from fossil marine mollusks. METHODOLOGY/PRINCIPAL FINDINGS: Organics consistent with β-chitin are recovered in cuttlebones of Mississaepia mississippiensis from the Late Eocene (34.36 million years ago marine clays of Hinds County, Mississippi, USA. These organics were determined and characterized through comparisons with extant taxa using Scanning Electron Microscopy/Energy Dispersive Spectrometry (SEM/EDS, Field Emission Scanning Electron Microscopy (Hyperprobe, Fourier Transmission Infrared Spectroscopy (FTIR and Immunohistochemistry (IHC. CONCLUSIONS/SIGNIFICANCE: Our study presents the first evidence for organics consistent with chitin from an ancient marine mollusk and discusses how these organics have been degraded over time. As mechanisms for their preservation, we propose that the inorganic/organic lamination of the cuttlebone, combined with a suboxic depositional environment with available free Fe(2+ ions, inhibited microbial or enzymatic degradation.

  20. 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

  1. The influence of HCl concentration and demineralization temperature of Atrina pectinata shells on quality of chitin

    Science.gov (United States)

    Nugroho, Intan Lazuardi; Pursetyo, Kustiawan Tri; Masithah, Endang Dewi

    2017-02-01

    Atrina pectinata is one of shells species widely consumed by people, which means the high consumption will generate the availability of shells in the environment as waste. Chitin can be produced from the shells. Shells contain quite high minerals that it should be demineralized to reduce the mineral content from the shells. This study aimed to determine the effect of HCl concentration and temperature affect chitin characteristics as the result of demineralization process from pen shells. The method based on two steps, there were demineralization and deproteination. This study used Completely Randomized Design (CRD) with two factors, including HCl concentration (2N, 4N, and 6N) and temperature (33°C and 60°C) which consists six combination treatments and three replications. Data was analyzed by using Analysis of Variance (ANOVA) and followed by Duncan's Multiple Range Test. The results showed that interaction of HCl concentration and temperature has significant effect (p<0.05) to ash content of chitin. The use concentration of 6N and 33°C produced the lowest ash content. Characteristics chitin resulted from the treatment of 6N and 33°C produced ash content 25.33% ± 6.82, moisture content 3.67% ± 1.10, yield 0.72% ± 0.12 and protein content 5.86%.

  2. 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

  3. A new type I peritrophic membrane protein from larval Holotrichia oblita (Coleoptera: Melolonthidae) binds to chitin.

    Science.gov (United States)

    Liu, Xiaomin; Li, Jie; Guo, Wei; Li, Ruijun; Zhao, Dan; Li, Xinna

    2014-04-22

    Peritrophic membranes (PMs) are composed of chitin and protein. Chitin and protein play important roles in the structural formation and function of the PM. A new type I PM protein, HoCBP76, was identified from the Holotrichia oblita. HoCBP76 was shown as a 62.3 kDa protein by SDS-PAGE analysis and appeard to be associated with the PM throughout its entire length. In H. oblita larvae, the midgut is the only tissue where HoCBP76 could be detected during the feeding period of the larvae. The predicted amino acid sequence indicates that it contains seven tandem chitin binding domains belonging to the peritrophin-A family. HoCBP76 has chitin binding activity and is strongly associated with the PM. The HoCBP76 was not a mucin-like glycoprotein, and the consensus of conserved cysteines appeared to be CX13-17CX5CX9CX12CX7C. Western blot analysis showed that the abundance of HoCBP76 in the anterior, middle and posterior regions of the midgut was similar, indicating that HoCBP76 was secreted by the whole midgut epithelium, and confirmed the H. oblita PM belonged to the Type I PM. Immunolocalization analysis showed that HoCBP76 was mainly localized in the PM. The HoCBP76 is the first PM protein found in the H. oblita; however, its biochemical and physiological functions require further investigation.

  4. 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

  5. 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...

  6. The role of novel chitin-like polysaccharides in Alzheimer disease.

    Science.gov (United States)

    Castellani, Rudy J; Perry, George; Smith, Mark A

    2007-12-01

    While controversy over the role of carbohydrates in amyloidosis has existed since the initial recognition of amyloid, current understanding of the role of polysaccharides in the pathogenesis of amyloid deposition of Alzheimer disease and other amyloidoses is limited to studies of glyco-conjugates such as heparin sulfate proteoglycan. We hypothesized that polysaccharides may play a broader role in light of 1) the impaired glucose utilization in Alzheimer disease; 2) the demonstration of amylose in the Alzheimer disease brain; 3) the role of amyloid in Alzheimer disease pathogenesis. Specifically, as with glucose polymers (amyloid), we wanted to explore whether glucosamine polymers such as chitin were being synthesized and deposited as a result of impaired glucose utilization and aberrant hexosamine pathway activation. To this end, using calcofluor histochemistry, we recently demonstrated that amyloid plaques and blood vessels affected by amyloid angiopathy in subjects with sporadic and familial Alzheimer disease elicit chitin-type characteristics. Since chitin is a highly insoluble molecule and a substrate for glycan-protein interactions, chitin-like polysaccharides within the Alzheimer disease brain could provide a scaffolding for amyloid-beta deposition. As such, glucosamine may facilitate the process of amyloidosis, and /or provide neuroprotection in the Alzheimer disease brain.

  7. 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.

  8. Human arylacetamide deacetylase hydrolyzes ketoconazole to trigger hepatocellular toxicity.

    Science.gov (United States)

    Fukami, Tatsuki; Iida, Azumi; Konishi, Keigo; Nakajima, Miki

    2016-09-15

    Ketoconazole (KC), an antifungal agent, rarely causes severe liver injury when orally administered. It has been reported that KC is mainly hydrolyzed to N-deacetyl ketoconazole (DAK), followed by the N-hydroxylation of DAK by flavin-containing monooxygenase (FMO). Although the metabolism of KC has been considered to be associated with hepatotoxicity, the responsible enzyme(s) remain unknown. The purpose of this study was to identify the responsible enzyme(s) for KC hydrolysis in humans and to clarify their relevance to KC-induced toxicity. Kinetic analysis and inhibition studies using human liver microsomes (HLM) and recombinant enzymes revealed that human arylacetamide deacetylase (AADAC) is responsible for KC hydrolysis to form DAK, and confirmed that FMO3 is the enzyme responsible for DAK N-hydroxylation. In HLM, the clearance of KC hydrolysis occurred to the same extent as DAK N-hydroxylation, which indicates that both processes are not rate-limiting pathways. Cytotoxicity of KC and DAK was evaluated using HepaRG cells and human primary hepatocytes. Treatment of HepaRG cells with DAK for 24h showed cytotoxicity in a dose-dependent manner, whereas treatment with KC did not show due to the low expression of AADAC. Overexpression of AADAC in HepaRG cells with an adenovirus expression system elicited the cytotoxicity of KC. Cytotoxicity of KC in human primary hepatocytes was attenuated by diisopropylfluorophosphate, an AADAC inhibitor. In conclusion, the present study demonstrated that human AADAC hydrolyzes KC to trigger hepatocellular toxicity.

  9. Histone deacetylase-mediated morphological transition in Candida albicans.

    Science.gov (United States)

    Kim, Jueun; Lee, Ji-Eun; Lee, Jung-Shin

    2015-12-01

    Candida albicans is the most common opportunistic fungal pathogen, which switches its morphology from single-cell yeast to filament through the various signaling pathways responding to diverse environmental cues. Various transcriptional factors such as Nrg1, Efg1, Brg1, Ssn6, and Tup1 are the key components of these signaling pathways. Since C. albicans can regulate its transcriptional gene expressions using common eukaryotic regulatory systems, its morphological transition by these signaling pathways could be linked to the epigenetic regulation by chromatin structure modifiers. Histone proteins, which are critical components of eukaryotic chromatin structure, can regulate the eukaryotic chromatin structure through their own modifications such as acetylation, methylation, phosphorylation and ubiquitylation. Recent studies revealed that various histone modifications, especially histone acetylation and deacetylation, participate in morphological transition of C. albicans collaborating with well-known transcription factors in the signaling pathways. Here, we review recent studies about chromatin-mediated morphological transition of C. albicans focusing on the interaction between transcription factors in the signaling pathways and histone deacetylases.

  10. Histone deacetylase inhibitors promote the tumoricidal effect of HAMLET.

    Science.gov (United States)

    Brest, Patrick; Gustafsson, Mattias; Mossberg, Ann-Kristin; Gustafsson, Lotta; Duringer, Caroline; Hamiche, Ali; Svanborg, Catharina

    2007-12-01

    Histone deacetylase inhibitors (HDIs) and HAMLET (human alpha-lactalbumin made lethal to tumor cells) interact with histones, modify the structure of chromatin, and trigger tumor cell death. This study investigated how the combination of HDIs and HAMLET influences cell viability, histone acetylation, and DNA integrity. The pretreatment of tumor cells with HDIs was shown to enhance the lethal effect of HAMLET and the histone hyperacetylation response to HDIs increased even further after HAMLET treatment. HDIs and HAMLET were shown to target different histone domains as HAMLET bound tailless core histones, whereas HDIs modify the acetylation of the histone tail. DNA damage in response to HAMLET was increased by HDIs. The DNA repair response (p21WAFI expression) was induced by both agonists but abolished when the two agonists were combined. The results suggest that the synergy of HDIs and HAMLET is based on different but converging death pathways, both involving chromatin alterations. We speculate that HAMLET and HDIs might be combined to promote tumor cell death in vivo.

  11. Comparative and pharmacophore model for deacetylase SIRT1

    Science.gov (United States)

    Huhtiniemi, Tero; Wittekindt, Carsten; Laitinen, Tuomo; Leppänen, Jukka; Salminen, Antero; Poso, Antti; Lahtela-Kakkonen, Maija

    2006-09-01

    Sirtuins are NAD-dependent histone deacetylases, which cleave the acetyl-group from acetylated proteins, such as histones but also the acetyl groups from several transcription factors, and in this way can change their activities. Of all seven mammalian SirTs, the human sirtuin SirT1 has been the most extensively studied. However, there is no crystal structure or comparative model reported for SirT1. We have therefore built up a three-dimensional comparison model of the SirT1 protein catalytic core (domain area from residues 244 to 498 of the full length SirT1) in order to assist in the investigation of active site-ligand interactions and in the design of novel SirT1 inhibitors. In this study we also propose the binding-mode of recently reported set of indole-based inhibitors in SirT1. The site of interaction and the ligand conformation were predicted by the use of molecular docking techniques. To distinguish between active and inactive compounds, a post-docking filter based on H-bond network was constructed. Docking results were used to investigate the pharmacophore and to identify a filter for database mining.

  12. Radiosensitization by histone deacetylase inhibition in an osteosarcoma mouse model

    Energy Technology Data Exchange (ETDEWEB)

    Blattmann, C. [Olgahospital, Stuttgart (Germany). Paediatrie 5; University Children' s Hospital of Heidelberg (Germany). Dept. of Pediatric Oncology, Hematology and Immunology; Thiemann, M. [German Cancer Research Center (DKFZ), Heidelberg (Germany). Dept. of Radiotherapy, Molecular- and Translational Radiation Oncology; Stenzinger, A. [Heidelberg Univ. (Germany). Inst. of Pathology; and others

    2013-11-15

    Background: Osteosarcomas (OS) are highly malignant and radioresistant tumors. Histone deacetylase inhibitors (HDACi) constitute a novel class of anticancer agents. We sought to investigate the effect of combined treatment with suberoylanilide hydroxamic acid (SAHA) and radiotherapy in OS in vivo. Methods: Clonogenic survival of human OS cell lines as well as tumor growth delay of OS xenografts were tested after treatment with either vehicle, radiotherapy (XRT), SAHA, or XRT and SAHA. Tumor proliferation, necrosis, microvascular density, apoptosis, and p53/p21 were monitored by immunohistochemistry. The CD95 pathway was performed by flow cytometry, caspase (3/7/8) activity measurements, and functional inhibition of CD95 death signaling. Results: Combined treatment with SAHA and XRT markedly reduced the surviving fraction of OS cells as compared to XRT alone. Likewise, dual therapy significantly inhibited OS tumor growth in vivo as compared to XRT alone, reflected by reduced tumor proliferation, impaired angiogenesis, and increased apoptosis. Addition of HDACi to XRT led to elevated p53, p21, CD95, and CD95L expression. Inhibition of CD95 signaling reduced HDACi- and XRT-induced apoptosis. Conclusion: Our data show that HDACi increases the radiosensitivity of osteosarcoma cells at least in part via ligand-induced apoptosis. HDACi thus emerge as potentially useful treatment components of OS. (orig.)

  13. 3D-QSAR Study on Apicidin Inhibit Histone Deacetylase

    Institute of Scientific and Technical Information of China (English)

    陈海峰; 康九红; 李强; 曾宝珊; 姚小军; 范波涛; 袁身刚; Panay,A.; Doucet,J.P.

    2003-01-01

    For Histone Deacetylase (HDAC) Inhibitor, four 3D-QSAR models for four types of different activities, were constructed.The cross-valldated q2 value of CoMFA Model 1 is 0.624 and the noncross-validated r2 value is 0.939. The cross-validated q2 value of Model 2 for training set is 0.652 and the noncross-validated r2 value is 0.963. The cross-validated q2 value for Model 3 is 0.713, with noncross-validated r2 value 0.947. The crossvalidated q2 value for Model 4 is 0.566 with noncross-validated r2 value 0.959. Their predicted abilities were validated by different test sets which did not include in training set. Then the relationship between substituents and activities was analyzed by using these models and the main influence elements in different positions (positions 8 and 14) were found. The polar donor electron group of position 8 could increase the activity of inhibition of HDAC, because it could form chelation with the catalytic Zn. Suitable bulk and positive groups at position 14 are favorable to anti-HDAC activity. These models could web interpret the relationship between inhibition activity and apicidin structure affording us important information for structurebased drug design.

  14. Role of histone deacetylases in gene regulation at nuclear lamina.

    Directory of Open Access Journals (Sweden)

    Beatrice C Milon

    Full Text Available Theoretical models suggest that gene silencing at the nuclear periphery may involve "closing" of chromatin by transcriptional repressors, such as histone deacetylases (HDACs. Here we provide experimental evidence confirming these predictions. Histone acetylation, chromatin compactness, and gene repression in lamina-interacting multigenic chromatin domains were analyzed in Drosophila S2 cells in which B-type lamin, diverse HDACs, and lamina-associated proteins were downregulated by dsRNA. Lamin depletion resulted in decreased compactness of the repressed multigenic domain associated with its detachment from the lamina and enhanced histone acetylation. Our data reveal the major role for HDAC1 in mediating deacetylation, chromatin compaction, and gene silencing in the multigenic domain, and an auxiliary role for HDAC3 that is required for retention of the domain at the lamina. These findings demonstrate the manifold and central involvement of class I HDACs in regulation of lamina-associated genes, illuminating a mechanism by which these enzymes can orchestrate normal and pathological development.

  15. Histone deacetylase inhibitors for treatment of hepatocellular carcinoma

    Institute of Scientific and Technical Information of China (English)

    Danila CORADINI; Annalisa SPERANZA

    2005-01-01

    Hepatocellular carcinoma (HCC) is one of the most common cancers in the world.Surgical resection has been considered the optimal treatment approach, but only a small proportion of patients are suitable candidates for surgery, and the relapse rate is high. Approaches to prevent recurrence, including chemoemboliza-tion before and adjuvant therapy after surgery, have proven to have a limited benefit;liver transplantation is successful in treating limited-stage HCC because only a minority of patients qualify for transplantation. Therefore, new therapeutic strategies are urgently needed. Because in addition to the classical genetic mechanisms of deletion or inactivating point mutations, epigenetic alterations, such as hyperacetylation of the chromatin-associated histones (responsible for gene silencing), are believed to be involved in the development and progression of HCC, novel compounds endowed with a histone deacetylase (HDAC) inhibitory activity are an attractive therapeutic approach. In particular, pre-clinical results obtained using HA-But, an HDAC inhibitor in which butyric acid residues are esterified to a hyaluronic acid backbone and characterized by a high affinity for the membrane receptor CD44, indicated that this class of compounds may represent a promising approach for hepatocellular carcinoma treatment.

  16. Dysregulation of Histone Acetyltransferases and Deacetylases in Cardiovascular Diseases

    Directory of Open Access Journals (Sweden)

    Yonggang Wang

    2014-01-01

    Full Text Available Cardiovascular disease (CVD remains a leading cause of mortality worldwide despite advances in its prevention and management. A comprehensive understanding of factors which contribute to CVD is required in order to develop more effective treatment options. Dysregulation of epigenetic posttranscriptional modifications of histones in chromatin is thought to be associated with the pathology of many disease models, including CVD. Histone acetyltransferases (HATs and deacetylases (HDACs are regulators of histone lysine acetylation. Recent studies have implicated a fundamental role of reversible protein acetylation in the regulation of CVDs such as hypertension, pulmonary hypertension, diabetic cardiomyopathy, coronary artery disease, arrhythmia, and heart failure. This reversible acetylation is governed by enzymes that HATs add or HDACs remove acetyl groups respectively. New evidence has revealed that histone acetylation regulators blunt cardiovascular and related disease states in certain cellular processes including myocyte hypertrophy, apoptosis, fibrosis, oxidative stress, and inflammation. The accumulating evidence of the detrimental role of histone acetylation in cardiac disease combined with the cardioprotective role of histone acetylation regulators suggests that the use of histone acetylation regulators may serve as a novel approach to treating the millions of patients afflicted by cardiac diseases worldwide.

  17. Histone Deacetylases and Their Inhibition in Candida Species

    Science.gov (United States)

    Garnaud, Cécile; Champleboux, Morgane; Maubon, Danièle; Cornet, Muriel; Govin, Jérôme

    2016-01-01

    Fungi are generally benign members of the human mucosal flora or live as saprophytes in the environment. However, they can become pathogenic, leading to invasive and life threatening infections in vulnerable patients. These invasive fungal infections are regarded as a major public health problem on a similar scale to tuberculosis or malaria. Current treatment for these infections is based on only four available drug classes. This limited therapeutic arsenal and the emergence of drug-resistant strains are a matter of concern due to the growing number of patients to be treated, and new therapeutic strategies are urgently needed. Adaptation of fungi to drug pressure involves transcriptional regulation, in which chromatin dynamics and histone modifications play a major role. Histone deacetylases (HDACs) remove acetyl groups from histones and actively participate in controlling stress responses. HDAC inhibition has been shown to limit fungal development, virulence, biofilm formation, and dissemination in the infected host, while also improving the efficacy of existing antifungal drugs toward Candida spp. In this article, we review the functional roles of HDACs and the biological effects of HDAC inhibitors on Candida spp., highlighting the correlations between their pathogenic effects in vitro and in vivo. We focus on how HDAC inhibitors could be used to treat invasive candidiasis while also reviewing recent developments in their clinical evaluation. PMID:27547205

  18. 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.

  19. Chitosan functional properties.

    Science.gov (United States)

    Shepherd, R; Reader, S; Falshaw, A

    1997-06-01

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

  20. 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.

  1. 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.

  2. NOVEL HYDROXAMIC ACIDS HAVING HISTONE DEACETYLASE INHIBITING ACTIVITY AND ANTI-CANCER COMPOSITION COMPRISING THE SAME AS AN ACTIVE INGREDIENT

    DEFF Research Database (Denmark)

    2013-01-01

    The present invention relates to a pharmaceutical composition for anticancer including novel hydroxamic acid with histone deacetylase inhibiting activity as an active ingredient. Hydroxamic acid compound of the present invention has inhibitory activity of histone deacetylase (HDAC) and shows cyto...... cytotoxicity to a variety of cancer cells, being useful in strong anti-cancer drug....

  3. Streptococcus mutans SMU.623c codes for a functional, metal-dependent polysaccharide deacetylase that modulates interactions with salivary agglutinin

    NARCIS (Netherlands)

    Deng, D.M.; Urch, J.E.; ten Cate, J.M.; Rao, V.A.; van Aalten, D.M.F.; Crielaard, W.

    2009-01-01

    The genome sequence of the oral pathogen Streptococcus mutans predicts the presence of two putative polysaccharide deacetylases. The first, designated PgdA in this paper, shows homology to the catalytic domains of peptidoglycan deacetylases from Streptococcus pneumoniae and Listeria monocytogenes, w

  4. Deacetylase inhibitors-focus on non-histone targets and effects

    Institute of Scientific and Technical Information of China (English)

    Matthias; Ocker

    2010-01-01

    Inhibitors of protein deacetylases have recently been established as a novel therapeutic principle for several human diseases,including cancer.The original notion of the mechanism of action of these compounds focused on the epigenetic control of transcriptional processes, especially of tumor suppressor genes,by interfering with the acetylation status of nuclear histone proteins,hence the name histone deacetylase inhibitors was coined.Yet,this view could not explain the high specificity for tumor cells and recent evidence now suggests that non-histone proteins represent major targets for protein deacetylase inhibitors and that the post-translational modification of the acetylome is involved in various cellular processes of differentiation,survival and cell death induction.

  5. Histone acetyltransferases and deacetylases: molecular and clinical implications to gastrointestinal carcinogenesis

    Institute of Scientific and Technical Information of China (English)

    Wei-Jian Sun; Xiang Zhou; Ji-Hang Zheng; Ming-Dong Lu; Jian-Yun Nie; Xiang-Jiao Yang; Zhi-Qiang Zheng

    2012-01-01

    Histone acetyltransferases and deacetylases are two groups of enzymes whose opposing activities govern the dynamic levels of reversible acetylation on specific lysine residues of histones and many other proteins.Gastrointestinal (GI) carcinogenesis is a major cause of morbidity and mortality worldwide.In addition to genetic and environmental factors,the role of epigenetic abnormalities such as aberrant histone acetylation has been recognized to be pivotal in regulating benign tumorigenesis and eventual malignant transformation.Here we provide an overview of histone acetylation,list the major groups of histone acetyltransferases and deacetylases,and cover in relatively more details the recent studies that suggest the links of these enzymes to GI carcinogenesis.As potential novel therapeutics for GI and other cancers,histone deacetylase inhibitors are also discussed.

  6. Inhibition of class IIb histone deacetylase significantly improves cloning efficiency in mice.

    Science.gov (United States)

    Ono, Tetsuo; Li, Chong; Mizutani, Eiji; Terashita, Yukari; Yamagata, Kazuo; Wakayama, Teruhiko

    2010-12-01

    Since the first mouse clone was produced by somatic cell nuclear transfer, the success rate of cloning in mice has been extremely low. Some histone deacetylase inhibitors, such as trichostatin A and scriptaid, have improved the full-term development of mouse clones significantly, but the mechanisms allowing for this are unclear. Here, we found that two other specific inhibitors, suberoylanilide hydroxamic acid and oxamflatin, could also reduce the rate of apoptosis in blastocysts, improve the full-term development of cloned mice, and increase establishment of nuclear transfer-generated embryonic stem cell lines significantly without leading to obvious abnormalities. However, another inhibitor, valproic acid, could not improve cloning efficiency. Suberoylanilide hydroxamic acid, oxamflatin, trichostatin A, and scriptaid are inhibitors for classes I and IIa/b histone deacetylase, whereas valproic acid is an inhibitor for classes I and IIa, suggesting that inhibiting class IIb histone deacetylase is an important step for reprogramming mouse cloning efficiency.

  7. Biomedical Exploitation of Chitin and Chitosan via Mechano-Chemical Disassembly, Electrospinning, Dissolution in Imidazolium Ionic Liquids, and Supercritical Drying

    OpenAIRE

    Riccardo A. A. Muzzarelli

    2011-01-01

    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 ...

  8. Morphological changes induced by class III chitin synthase gene silencing could enhance penicillin production of Penicillium chrysogenum.

    Science.gov (United States)

    Liu, Hui; Zheng, Zhiming; Wang, Peng; Gong, Guohong; Wang, Li; Zhao, Genhai

    2013-04-01

    Chitin synthases catalyze the formation of β-(1,4)-glycosidic bonds between N-acetylglucosamine residues to form the unbranched polysaccharide chitin, which is the major component of cell walls in most filamentous fungi. Several studies have shown that chitin synthases are structurally and functionally divergent and play crucial roles in the growth and morphogenesis of the genus Aspergillus although little research on this topic has been done in Penicillium chrysogenum. We used BLAST to find the genes encoding chitin synthases in P. chrysogenum related to chitin synthase genes in Aspergillus nidulans. Three homologous sequences coding for a class III chitin synthase CHS4 and two hypothetical proteins in P. chrysogenum were found. The gene which product showed the highest identity and encoded the class III chitin synthase CHS4 was studied in detail. To investigate the role of CHS4 in P. chrysogenum morphogenesis, we developed an RNA interference system to silence the class III chitin synthase gene chs4. After transformation, mutants exhibited a slow growth rate and shorter and more branched hyphae, which were distinct from those of the original strain. The results also showed that the conidiation efficiency of all transformants was reduced sharply and indicated that chs4 is essential in conidia development. The morphologies of all transformants and the original strain in penicillin production were investigated by light microscopy, which showed that changes in chs4 expression led to a completely different morphology during fermentation and eventually caused distinct penicillin yields, especially in the transformants PcRNAi1-17 and PcRNAi2-1 where penicillin production rose by 27 % and 41 %, respectively.

  9. 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.

  10. Histone deacetylase inhibitors: a potential epigenetic treatment for Duchenne muscular dystrophy.

    Science.gov (United States)

    Consalvi, Silvia; Saccone, Valentina; Mozzetta, Chiara

    2014-01-01

    Duchenne muscular dystrophy (DMD) is a life-threatening genetic disease that currently has no available cure. A number of pharmacological strategies that aim to target events downstream of the genetic defect are currently under clinical investigation, and some of these are outlined in this report. In particular, we focus on the ability of histone deacetylase inhibitors to promote muscle regeneration and prevent the fibro-adipogenic degeneration of dystrophic mice. We describe the rationale behind the translation of histone deacetylase inhibitors into a clinical approach, which inspired the first clinical trial with an epigenetic drug as a potential therapeutic option for DMD patients.

  11. The Effect of Various Zinc Binding Groups on Inhibition of Histone Deacetylases 1–11

    DEFF Research Database (Denmark)

    Madsen, Andreas Stahl; Kristensen, Helle M. E.; Lanz, Gyrithe;

    2014-01-01

    Histone deacetylases (HDACs) have the ability to cleave the acetyl groups of ε‐N‐acetylated lysine residues in a variety of proteins. Given that human cells contain thousands of different acetylated lysine residues, HDACS may regulate a wide variety of processes including some implicated in condi......Histone deacetylases (HDACs) have the ability to cleave the acetyl groups of ε‐N‐acetylated lysine residues in a variety of proteins. Given that human cells contain thousands of different acetylated lysine residues, HDACS may regulate a wide variety of processes including some implicated...

  12. Lysine deacetylases are produced in pancreatic beta cells and are differentially regulated by proinflammatory cytokines

    DEFF Research Database (Denmark)

    Lundh, M; Christensen, D P; Rasmussen, D N;

    2010-01-01

    Cytokine-induced beta cell toxicity is abrogated by non-selective inhibitors of lysine deacetylases (KDACs). The KDAC family consists of 11 members, namely histone deacetylases HDAC1 to HDAC11, but it is not known which KDAC members play a role in cytokine-mediated beta cell death. The aim...... of the present study was to examine the KDAC gene expression profile of the beta cell and to investigate whether KDAC expression is regulated by cytokines. In addition, the protective effect of the non-selective KDAC inhibitor ITF2357 and interdependent regulation of four selected KDACs were investigated....

  13. Antagonistic effect of chitin-degrading microfungi on thick-shelled pig helminth eggs

    OpenAIRE

    Katakam, Kiran Kumar; Thapa, Sundar; Meyling, Nicholai V.; Dalsgaard, Anders; Roepstorff, Allan; Thamsborg, Stig Milan

    2011-01-01

    The rising demand for pigs produced in organic farming systems, which require access to outdoor areas and associated increased risk of gastrointestinal nematode infections, is creating growing interest in alternative control strategies. Also development of anthelminthic resistance due to extensive use of anthelmintics is a concern in intensive pig production. Use of chitin-degrading microfungi is one of the options. Extensive research has been conducted on biological control of plant pathogen...

  14. A New Type I Peritrophic Membrane Protein from Larval Holotrichia oblita (Coleoptera: Melolonthidae Binds to Chitin

    Directory of Open Access Journals (Sweden)

    Xiaomin Liu

    2014-04-01

    Full Text Available Peritrophic membranes (PMs are composed of chitin and protein. Chitin and protein play important roles in the structural formation and function of the PM. A new type I PM protein, HoCBP76, was identified from the Holotrichia oblita. HoCBP76 was shown as a 62.3 kDa protein by SDS-PAGE analysis and appeard to be associated with the PM throughout its entire length. In H. oblita larvae, the midgut is the only tissue where HoCBP76 could be detected during the feeding period of the larvae. The predicted amino acid sequence indicates that it contains seven tandem chitin binding domains belonging to the peritrophin-A family. HoCBP76 has chitin binding activity and is strongly associated with the PM. The HoCBP76 was not a mucin-like glycoprotein, and the consensus of conserved cysteines appeared to be CX13–17CX5CX9CX12CX7C. Western blot analysis showed that the abundance of HoCBP76 in the anterior, middle and posterior regions of the midgut was similar, indicating that HoCBP76 was secreted by the whole midgut epithelium, and confirmed the H. oblita PM belonged to the Type I PM. Immunolocalization analysis showed that HoCBP76 was mainly localized in the PM. The HoCBP76 is the first PM protein found in the H. oblita; however, its biochemical and physiological functions require further investigation.

  15. NATURAL POLYMERS: CELLULOSE, CHITIN, CHITOSAN, GELATIN, STARCH, CARRAGEENAN, XYLAN AND DEXTRAN

    Directory of Open Access Journals (Sweden)

    Fatma Zohra Benabid

    2016-12-01

    Full Text Available Biopolymers have been investigated for drug fields. They are widely being studied because of their non-toxic and biocompatible in nature. Biopolymers are used in industries as diverse as paper, plastics, food, textiles, pharmaceuticals, and cosmetics.This review covers different natural polymers, recent techniques applied in their processing and characterization. Advanced applications of natural polymers, including chitin, chitosan, alginate, etc., are discussed.

  16. 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.

  17. Preparation of polysilsesquioxane-urethaneacrylate copolymer film reinforced with chitin nanofibers.

    Science.gov (United States)

    Ifuku, Shinsuke; Ikuta, Akiko; Hosomi, Tetsuya; Kanaya, Shingo; Shervani, Zameer; Morimoto, Minoru; Saimoto, Hiroyuki

    2012-07-01

    Chitin nanofibers (CNFs) reinforced silsesquioxane-urethaneacrylate (SSQ-UA) copolymer films were prepared. CNFs-SSQ-UA nanocomposite films were highly transparent due to the filling of nanometer sized (10-20 nm) CNFs inside the hybrid organic-inorganic SSQ-UA copolymer. CNFs due to their crystalline structure drastically increased Young's moduli and the tensile strengths of the composite and decreased the thermal expansion. High thermal stability of polysilsesquioxane improved heat resistance of CNFs.

  18. An insecticidal GroEL protein with chitin binding activity from Xenorhabdus nematophila.

    Science.gov (United States)

    Joshi, Mohan Chandra; Sharma, Animesh; Kant, Sashi; Birah, Ajanta; Gupta, Gorakh Prasad; Khan, Sharik R; Bhatnagar, Rakesh; Banerjee, Nirupama

    2008-10-17

    Xenorhabdus nematophila secretes insecticidal proteins to kill its larval prey. We have isolated an approximately 58-kDa GroEL homolog, secreted in the culture medium through outer membrane vesicles. The protein was orally insecticidal to the major crop pest Helicoverpa armigera with an LC50 of approximately 3.6 microg/g diet. For optimal insecticidal activity all three domains of the protein, apical, intermediate, and equatorial, were necessary. The apical domain alone was able to bind to the larval gut membranes and manifest low level insecticidal activity. At equimolar concentrations, the apical domain contained approximately one-third and the apical-intermediate domain approximately one-half bioactivity of that of the full-length protein. Interaction of the protein with the larval gut membrane was specifically inhibited by N-acetylglucosamine and chito-oligosaccharides. Treatment of the larval gut membranes with chitinase abolished protein binding. Based on the three-dimensional structural model, mutational analysis demonstrated that surface-exposed residues Thr-347 and Ser-356 in the apical domain were crucial for both binding to the gut epithelium and insecticidal activity. Double mutant T347A,S356A was 80% less toxic (p activity with Kd approximately 0.64 microm and Bmax approximately 4.68 micromol/g chitin. The variation in chitin binding activity of the mutant proteins was in good agreement with membrane binding characteristics and insecticidal activity. The less toxic double mutant XnGroEL showed an approximately 8-fold increase of Kd in chitin binding assay. Our results demonstrate that X. nematophila secretes an insecticidal GroEL protein with chitin binding activity.

  19. The biocompatibility of dibutyryl chitin in the context of wound dressings.

    Science.gov (United States)

    Muzzarelli, Riccardo A A; Guerrieri, Mario; Goteri, Gaia; Muzzarelli, Corrado; Armeni, Tatiana; Ghiselli, Roberto; Cornelissen, Maria

    2005-10-01

    Dibutyryl chitin (DBC) is a modified chitin carrying butyryl groups at 3 and 6 positions; its peculiarity is that it dissolves promptly in common solvents, while being insoluble in aqueous systems. The high biocompatibility of dibutyryl chitin in the form of films and non-wovens has been demonstrated for human, chick and mouse fibroblasts by the Viability/Cytotoxicity assay, In situ Cell Proliferation assay, Neutral Red Retention assay, Lactate Dehydrogenase Release assay, MTS cytotoxicity assay, and scanning electron microscopy. DBC was hardly degradable by lysozyme, amylase, collagenase, pectinase and cellulase over the observation period of 48 days at room temperature, during which no more than 1.33% by weight of the DBC filaments (0.3 mm diameter) was released to the aqueous medium. DBC non-wovens were incorporated into 5-methylpyrrolidinone chitosan solution and submitted to freeze-drying to produce a reinforced wound dressing material. The latter was tested in vivo in full thickness wounds in rats. The insertion of 4x4 mm pieces did not promote any adverse effect on the healing process, as shown histologically. DBC is therefore suitable for contacting intact and wounded human tissues.

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

    Directory of Open Access Journals (Sweden)

    José M. Franco

    2013-06-01

    Full Text Available 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.

  1. Chitin and chitosan from the Norway lobster by-products: Antimicrobial and anti-proliferative activities.

    Science.gov (United States)

    Sayari, Nadhem; Sila, Assaâd; Abdelmalek, Baha Eddine; Abdallah, Rihab Ben; Ellouz-Chaabouni, Semia; Bougatef, Ali; Balti, Rafik

    2016-06-01

    Chitin was recovered through enzymatic deproteinization of the Norway lobster (Nephrops norvegicus) processing by-products. The obtained chitin was characterized and converted into chitosan by N-deacetylation, the acid-soluble form of chitin. Chitosan samples were then characterized by Fourier transform infrared spectroscopy (FTIR) and 13 Cross polarization magic angle spinning nuclear magnetic resonance (CP/MAS)-NMR spectroscopy. The antimicrobial activity and anti-proliferative capacity of chitosan were evaluated. Antimicrobial activity assays indicated that prepared chitosan exhibited marked inhibitory activity against the bacterial and fungal strains tested. Further, cytotoxic effects of chitosan samples on human colon carcinoma cells HCT116 was evaluated using the MTT assay. Chitosan showed the antiproliferative capacity against the colon-cancer-cell HCT116 in a dose dependent manner with IC50 of 4.6mg/ml. Indeed, HCT116 cell proliferation was significantly inhibited (p<0.05) between 13.5 and 67.5% at 0.5-6mg/mL of chitosan after 24h of cell treatment. The chitosan showed high antitumor activity which seemed to be dependent on its characteristics such as acetylation degree.

  2. 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

    2016-11-05

    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).

  3. 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.

  4. 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.

  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. Downregulation of HMGA2 by the pan-deacetylase inhibitor panobinostat is dependent on hsa-let-7b expression in liver cancer cell lines

    Energy Technology Data Exchange (ETDEWEB)

    Di Fazio, Pietro, E-mail: difazio@med.uni-marburg.de [Institute for Surgical Research, Philipps University of Marburg, Baldingerstrasse, 35043 Marburg (Germany); Montalbano, Roberta [Institute for Surgical Research, Philipps University of Marburg, Baldingerstrasse, 35043 Marburg (Germany); Neureiter, Daniel; Alinger, Beate [Institute of Pathology, Paracelsus Private Medical University of Salzburg, Salzburg (Austria); Schmidt, Ansgar [Institute for Pathology, Philipps University of Marburg, Marburg (Germany); Merkel, Anna Lena; Quint, Karl; Ocker, Matthias [Institute for Surgical Research, Philipps University of Marburg, Baldingerstrasse, 35043 Marburg (Germany)

    2012-09-10

    Inhibitors of protein deacetylases represent a novel therapeutic option for cancer diseases due to their effects on transcriptional regulation by interfering with histones acetylation and on several other cellular pathways. Recently, their ability to modulate several transcription factors and, interestingly, also co-factors, which actively participate in formation and modulation of transcription complexes was shown. We here investigate whether HMGA2 (High Mobility Group AT-2 hook), a nuclear non-histone transcriptional co-factor with known oncogenic properties, can be influenced by the novel pan-deacetylase inhibitor panobinostat (LBH589) in human hepatocellular carcinoma models. Panobinostat strongly downregulated HMGA2 in HepG2 and Hep3B cells; this effect was mediated by transcriptional upregulation and promotion of the maturation of the tumorsuppressor miRNA hsa-let-7b, which could inhibit HMGA2 expression via RNA interference pathways. siRNA knockdown of HMGA2 or transfection of hsa-let-7b mimicking oligonucleotides confirmed the role of HMGA2 in regulating cell proliferation and apoptosis in liver cancer cell lines. Co-incubation with panobinostat showed an additive effect on inhibition of cell proliferation using an impedance-based real-time cell analyzer. Treatment of HepG2 xenografts with panobinostat also led to a downregulation of HMGA2 in vivo. These findings show that pan-deacetylase inhibitors also modulate other signaling pathways and networks than histone modifications to influence cell fate. -- Highlights: Black-Right-Pointing-Pointer Panobinostat for the treatment of liver cancer. Black-Right-Pointing-Pointer Panobinostat meddles with miRNAs-dependent transcriptional and translational control. Black-Right-Pointing-Pointer Tumorsuppressor miRNA hsa-let-7b upregulation. Black-Right-Pointing-Pointer HMGA2 is downregulated via RNA interference pathways mediated by hsa-let-7b. Black-Right-Pointing-Pointer Panobinostat determines inhibition of

  7. 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.

  8. Proteomic investigations of lysine acetylation identify diverse substrates of mitochondrial deacetylase sirt3.

    Directory of Open Access Journals (Sweden)

    Eri Maria Sol

    Full Text Available Lysine acetylation is a posttranslational modification that is dynamically regulated by the activity of acetyltransferases and deacetylases. The human and mouse genomes encode 18 different lysine deacetylases (KDACs which are key regulators of many cellular processes. Identifying substrates of KDACs and pinpointing the regulated acetylation sites on target proteins may provide important information about the molecular basis of their functions. Here we apply quantitative proteomics to identify endogenous substrates of the mitochondrial deacetylase Sirtuin 3 (Sirt3 by comparing site-specific acetylation in wild-type murine embryonic fibroblasts to Sirt3 knockout cells. We confirm Sirt3-regulated acetylation of several mitochondrial proteins in human cells by comparing acetylation in U2OS cells overexpressing Sirt3 to U2OS cells in which Sirt3 expression was reduced by shRNA. Our data demonstrate that ablation of Sirt3 significantly increases acetylation at dozens of sites on mitochondrial proteins. Substrates of Sirt3 are implicated in various metabolic pathways, including fatty acid metabolism and the tricarboxylic acid cycle. These results imply broader regulatory roles of Sirt3 in the mitochondria by modulating acetylation on diverse substrates. The experimental strategy described here is generic and can be applied to identify endogenous substrates of other lysine deacetylases.

  9. A truncating mutation of HDAC2 in human cancers confers resistance to histone deacetylase inhibition

    DEFF Research Database (Denmark)

    Ropero, S; Fraga, MF; Ballestar, E;

    2006-01-01

    Disruption of histone acetylation patterns is a common feature of cancer cells, but very little is known about its genetic basis. We have identified truncating mutations in one of the primary human histone deacetylases, HDAC2, in sporadic carcinomas with microsatellite instability and in tumors a...

  10. The flavoring agent dihydrocoumarin reverses epigenetic silencing and inhibits sirtuin deacetylases.

    Directory of Open Access Journals (Sweden)

    Andrew J Olaharski

    2005-12-01

    Full Text Available Sirtuins are a family of phylogenetically conserved nicotinamide adenine dinucleotide-dependent deacetylases that have a firmly established role in aging. Using a simple Saccharomyces cerevisiae yeast heterochromatic derepression assay, we tested a number of environmental chemicals to address the possibility that humans are exposed to sirtuin inhibitors. Here we show that dihydrocoumarin (DHC, a compound found in Melilotus officinalis (sweet clover that is commonly added to food and cosmetics, disrupted heterochromatic silencing and inhibited yeast Sir2p as well as human SIRT1 deacetylase activity. DHC exposure in the human TK6 lymphoblastoid cell line also caused concentration-dependent increases in p53 acetylation and cytotoxicity. Flow cytometric analysis to detect annexin V binding to phosphatidylserine demonstrated that DHC increased apoptosis more than 3-fold over controls. Thus, DHC inhibits both yeast Sir2p and human SIRT1 deacetylases and increases p53 acetylation and apoptosis, a phenotype associated with senescence and aging. These findings demonstrate that humans are potentially exposed to epigenetic toxicants that inhibit sirtuin deacetylases.

  11. The histone deacetylase inhibitor Trichostatin A modulates CD4+ T cell responses

    DEFF Research Database (Denmark)

    Moreira, José Manuel Alfonso; Scheipers, Peter; Sørensen, Poul

    2003-01-01

    Histone deacetylase inhibitors (HDACIs) induce hyperacetylation of core histones modulating chromatin structure and affecting gene expression. These compounds are also able to induce growth arrest, cell differentiation, and apoptotic cell death of tumor cells in vitro as well as in vivo. Even tho...

  12. The histone deacetylase inhibitor panobinostat lowers biomarkers of cardiovascular risk and inflammation in HIV patients

    NARCIS (Netherlands)

    Kjaer, A.S. Hogh Kolbaek; Brinkmann, C.R.; Dinarello, C.A.; Olesen, R.; Ostergaard, L.; Sogaard, O.S.; Tolstrup, M.; Rasmussen, T.A.

    2015-01-01

    OBJECTIVE: To investigate the effect of the histone deacetylase inhibitor panobinostat on HIV-associated inflammation. DESIGN: Sub-study of a single-arm, phase I/II clinical trial. METHODS: HIV-infected adults on suppressive antiretroviral therapy received oral panobinostat 20 mg three times per wee

  13. Histone deacetylase (HDAC) inhibition as a novel treatment for diabetes mellitus

    DEFF Research Database (Denmark)

    Christensen, Dan P; Dahllöf, Mattias Salling; Lundh, Morten;

    2011-01-01

    of genetic association between diabetes and histone deacetylases (HDACs); and HDAC inhibitors (HDACi) promote ß-cell development, proliferation, differentiation and function and positively affect late diabetic microvascular complications. Here we review this evidence and propose that there is a strong...

  14. A Role for Histone Deacetylases in the Cellular and Behavioral Mechanisms Underlying Learning and Memory

    Science.gov (United States)

    Mahgoub, Melissa; Monteggia, Lisa M.

    2014-01-01

    Histone deacetylases (HDACs) are a family of chromatin remodeling enzymes that restrict access of transcription factors to the DNA, thereby repressing gene expression. In contrast, histone acetyltransferases (HATs) relax the chromatin structure allowing for an active chromatin state and promoting gene transcription. Accumulating data have…

  15. Methyl Effect in Azumamides Provides Insight Into Histone Deacetylase Inhibition by Macrocycles

    DEFF Research Database (Denmark)

    Maolanon, Alex; Villadsen, Jesper; Christensen, Niels Johan;

    2014-01-01

    Natural, nonribosomal cyclotetrapeptides have traditionally been a rich source of inspiration for design of potent histone deacetylase (HDAC) inhibitors. We recently disclosed the total synthesis and full HDAC pro fi ling of the naturally occurring azumamides ( J. Med. Chem. 2013 , 56 , 6512). In...

  16. Identification of 20-hydroxyecdysone late-response genes in the chitin biosynthesis pathway.

    Directory of Open Access Journals (Sweden)

    Qiong Yao

    Full Text Available BACKGROUND: 20-hydroxyecdysone (20E and its receptor complex ecdysone receptor (EcR and ultraspiracle (USP play a crucial role in controlling development, metamorphosis, reproduction and diapause. The ligand-receptor complex 20E-EcR/USP directly activates a small set of early-response genes and a much larger set of late-response genes. However, ecdysone-responsive genes have not been previously characterized in the context of insect chitin biosynthesis. PRINCIPAL FINDINGS: Here, we show that injection-based RNA interference (RNAi directed towards a common region of the two isoforms of SeEcR in a lepidopteron insect Spodoptera exigua was effective, with phenotypes including a high mortality prior to pupation and developmental defects. After gene specific RNAi, chitin contents in the cuticle of an abnormal larva significantly decreased. The expression levels of five genes in the chitin biosynthesis pathway, SeTre-1, SeG6PI, SeUAP, SeCHSA and SeCHSB, were significantly reduced, while there was no difference in the expression of SeTre-2 prior to 72 hr after injection of EcR dsRNA. Meanwhile, injection of 20E in vivo induced the expression of the five genes mentioned above. Moreover, the SeTre-1, SeG6PI, SeUAP and SeCHSB genes showed late responses to the hormone and the induction of SeTre-1, SeG6PI, SeUAP and SeCHSB genes by 20E were able to be inhibited by the protein synthesis inhibitor cycloheximide in vitro indicating these genes are 20E late-response genes. CONCLUSIONS: We conclude that SeTre-1, SeG6PI, SeUAP and SeCHSB in the chitin biosynthesis pathway are 20E late-response genes and 20E and its specific receptors plays a key role in the regulation of chitin biosynthesis via inducing their expression.

  17. 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

  18. 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.

  19. 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.

  20. 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

  1. Bicyclic-Capped Histone Deacetylase 6 Inhibitors with Improved Activity in a Model of Axonal Charcot-Marie-Tooth Disease.

    Science.gov (United States)

    Shen, Sida; Benoy, Veronick; Bergman, Joel A; Kalin, Jay H; Frojuello, Mariana; Vistoli, Giulio; Haeck, Wanda; Van Den Bosch, Ludo; Kozikowski, Alan P

    2016-02-17

    Charcot-Marie-Tooth (CMT) disease is a disorder of the peripheral nervous system where progressive degeneration of motor and sensory nerves leads to motor problems and sensory loss and for which no pharmacological treatment is available. Recently, it has been shown in a model for the axonal form of CMT that histone deacetylase 6 (HDAC6) can serve as a target for the development of a pharmacological therapy. Therefore, we aimed at developing new selective and activity-specific HDAC6 inhibitors with improved biochemical properties. By utilizing a bicyclic cap as the structural scaffold from which to build upon, we developed several analogues that showed improved potency compared to tubastatin A while maintaining excellent selectivity compared to HDAC1. Further screening in N2a cells examining both the acetylation of α-tubulin and histones narrowed down the library of compounds to three potent and selective HDAC6 inhibitors. In mutant HSPB1-expressing DRG neurons, serving as an in vitro model for CMT2, these inhibitors were able to restore the mitochondrial axonal transport deficits. Combining structure-based development of HDAC6 inhibitors, screening in N2a cells and in a neuronal model for CMT2F, and preliminary ADMET and pharmacokinetic profiles, resulted in the selection of compound 23d that possesses improved biochemical, functional, and druglike properties compared to tubastatin A.

  2. Chitin amendment raises the suppressiveness of soil towards plant pathogens and modulates the actinobacterial and oxalobacteriaceal communities in an experimental agricultural field

    NARCIS (Netherlands)

    Cretoiu, M.S.; Korthals, G.W.; Visser, J.H.M.; Elsas, van J.D.

    2013-01-01

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

  3. Reshuffling of Aspergillus fumigatus cell wall components chitin and β-glucan under the influence of caspofungin or nikkomycin Z alone or in combination

    NARCIS (Netherlands)

    P.E.B. Verwer (Patricia); H.M. van Duijn (Miranda); M. Tavakol (Mehri); I.A.J.M. Bakker-Woudenberg (Irma); W.W.J. van de Sande (Wendy)

    2012-01-01

    textabstractChitin and β-glucan are major cell wall components of Aspergillus spp. We investigated the antifungal activity of chitin synthesis inhibitors nikkomycin Z, polyoxin D, flufenoxuron, lufenuron, and teflubenzuron, alone and combined with the β-glucan synthesis inhibitor caspofungin. Only n

  4. Histone Deacetylase 3 Coordinates Deacetylase-independent Epigenetic Silencing of Transforming Growth Factor-β1 (TGF-β1) to Orchestrate Second Heart Field Development*

    Science.gov (United States)

    Lewandowski, Sara L.; Janardhan, Harish P.; Trivedi, Chinmay M.

    2015-01-01

    About two-thirds of human congenital heart disease involves second heart field-derived structures. Histone-modifying enzymes, histone deacetylases (HDACs), regulate the epigenome; however, their functions within the second heart field remain elusive. Here we demonstrate that histone deacetylase 3 (HDAC3) orchestrates epigenetic silencing of Tgf-β1, a causative factor in congenital heart disease pathogenesis, in a deacetylase-independent manner to regulate development of second heart field-derived structures. In murine embryos lacking HDAC3 in the second heart field, increased TGF-β1 bioavailability is associated with ascending aortic dilatation, outflow tract malrotation, overriding aorta, double outlet right ventricle, aberrant semilunar valve development, bicuspid aortic valve, ventricular septal defects, and embryonic lethality. Activation of TGF-β signaling causes aberrant endothelial-to-mesenchymal transition and altered extracellular matrix homeostasis in HDAC3-null outflow tracts and semilunar valves, and pharmacological inhibition of TGF-β rescues these defects. HDAC3 recruits components of the PRC2 complex, methyltransferase EZH2, EED, and SUZ12, to the NCOR complex to enrich trimethylation of Lys-27 on histone H3 at the Tgf-β1 regulatory region and thereby maintains epigenetic silencing of Tgf-β1 specifically within the second heart field-derived mesenchyme. Wild-type HDAC3 or catalytically inactive HDAC3 expression rescues aberrant endothelial-to-mesenchymal transition and epigenetic silencing of Tgf-β1 in HDAC3-null outflow tracts and semilunar valves. These findings reveal that epigenetic dysregulation within the second heart field is a predisposing factor for congenital heart disease. PMID:26420484

  5. Histone Deacetylase 3 Coordinates Deacetylase-independent Epigenetic Silencing of Transforming Growth Factor-β1 (TGF-β1) to Orchestrate Second Heart Field Development.

    Science.gov (United States)

    Lewandowski, Sara L; Janardhan, Harish P; Trivedi, Chinmay M

    2015-11-06

    About two-thirds of human congenital heart disease involves second heart field-derived structures. Histone-modifying enzymes, histone deacetylases (HDACs), regulate the epigenome; however, their functions within the second heart field remain elusive. Here we demonstrate that histone deacetylase 3 (HDAC3) orchestrates epigenetic silencing of Tgf-β1, a causative factor in congenital heart disease pathogenesis, in a deacetylase-independent manner to regulate development of second heart field-derived structures. In murine embryos lacking HDAC3 in the second heart field, increased TGF-β1 bioavailability is associated with ascending aortic dilatation, outflow tract malrotation, overriding aorta, double outlet right ventricle, aberrant semilunar valve development, bicuspid aortic valve, ventricular septal defects, and embryonic lethality. Activation of TGF-β signaling causes aberrant endothelial-to-mesenchymal transition and altered extracellular matrix homeostasis in HDAC3-null outflow tracts and semilunar valves, and pharmacological inhibition of TGF-β rescues these defects. HDAC3 recruits components of the PRC2 complex, methyltransferase EZH2, EED, and SUZ12, to the NCOR complex to enrich trimethylation of Lys-27 on histone H3 at the Tgf-β1 regulatory region and thereby maintains epigenetic silencing of Tgf-β1 specifically within the second heart field-derived mesenchyme. Wild-type HDAC3 or catalytically inactive HDAC3 expression rescues aberrant endothelial-to-mesenchymal transition and epigenetic silencing of Tgf-β1 in HDAC3-null outflow tracts and semilunar valves. These findings reveal that epigenetic dysregulation within the second heart field is a predisposing factor for congenital heart disease.

  6. The histone acetyltransferase p300 inhibitor C646 reduces pro-inflammatory gene expression and inhibits histone deacetylases

    NARCIS (Netherlands)

    van den Bosch, Thea; Boichenko, Alexander; Leus, Niek G J; Ourailidou, Maria Eleni; Wapenaar, Hannah; Rotili, Dante; Mai, Antonello; Imhof, Axel; Bischoff, Rainer; Haisma, Hidde J; Dekker, Frank J

    2016-01-01

    Lysine acetylations are reversible posttranslational modifications of histone and non-histone proteins that play important regulatory roles in signal transduction cascades and gene expression. Lysine acetylations are regulated by histone acetyltransferases as writers and histone deacetylases as eras

  7. Optimization and adsorption kinetic studies of aqueous manganese ion removal using chitin extracted from shells of edible Philippine crabs

    Science.gov (United States)

    Quimque, Mark Tristan J.; Jimenez, Marvin C.; Acas, Meg Ina S.; Indoc, Danrelle Keth L.; Gomez, Enjelyn C.; Tabuñag, Jenny Syl D.

    2017-01-01

    Manganese is a common contaminant in drinking water along with other metal pollutants. This paper investigates the use of chitin, extracted from crab shells obtained as restaurant throwaway, as an adsorbent in removing manganese ions from aqueous medium. In particular, this aims to optimize the adsorption parameters and look into the kinetics of the process. The adsorption experiments done in this study employed the batch equilibration method. In the optimization, the following parameters were considered: pH and concentration of Mn (II) sorbate solution, particle size and dosage of adsorbent chitin, and adsorbent-adsorbate contact time. At the optimal condition, the order of the adsorption reaction was estimated using kinetic models which describes the process best. It was found out that the adsorption of aqueous Mn (II) ions onto chitin obeys the pseudo-second order model. This model assumes that the adsorption occurred via chemisorption

  8. The chiral structure of porous chitin within the wing-scales of Callophrys rubi.

    Science.gov (United States)

    Schröder-Turk, G E; Wickham, S; Averdunk, H; Brink, F; Fitz Gerald, J D; Poladian, L; Large, M C J; Hyde, S T

    2011-05-01

    The structure of the porous three-dimensional reticulated pattern in the wing scales of the butterfly Callophrys rubi (the Green Hairstreak) is explored in detail, via scanning and transmission electron microscopy. A full 3D tomographic reconstruction of a section of this material reveals that the predominantly chitin material is assembled in the wing scale to form a structure whose geometry bears a remarkable correspondence to the srs net, well-known in solid state chemistry and soft materials science. The porous solid is bounded to an excellent approximation by a parallel surface to the Gyroid, a three-periodic minimal surface with cubic crystallographic symmetry I4₁32, as foreshadowed by Stavenga and Michielson. The scale of the structure is commensurate with the wavelength of visible light, with an edge of the conventional cubic unit cell of the parallel-Gyroid of approximately 310 nm. The genesis of this structure is discussed, and we suggest it affords a remarkable example of templating of a chiral material via soft matter, analogous to the formation of mesoporous silica via surfactant assemblies in solution. In the butterfly, the templating is achieved by the lipid-protein membranes within the smooth endoplasmic reticulum (while it remains in the chrysalis), that likely form cubic membranes, folded according to the form of the Gyroid. The subsequent formation of the chiral hard chitin framework is suggested to be driven by the gradual polymerisation of the chitin precursors, whose inherent chiral assembly in solution (during growth) promotes the formation of a single enantiomer.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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

  14. 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

  15. Histone deacetylases inhibitor trichostatin A modulates the extracellular release of APE1/Ref-1.

    Science.gov (United States)

    Choi, Sunga; Lee, Yu Ran; Park, Myoung Soo; Joo, Hee Kyoung; Cho, Eun Jung; Kim, Hyo Shin; Kim, Cuk Seong; Park, Jin Bong; Irani, Kaikobad; Jeon, Byeong Hwa

    2013-06-01

    Apurinic/apyrimidinic endonuclease 1/Redox factor-1 (APE1/Ref-1) can be acetylated via post-translational modification. We investigated the effect of an inhibitor of histone deacetylases on the extracellular release of APE1/Ref-1 in HEK293 cells. Trichostatin A (TSA), an inhibitor of histone deacetylases, induced APE1/Ref-1 secretion without changing cell viability. In a fluorescence quantitative assay, the secreted APE1/Ref-1 was estimated to be about 10 ng/mL in response to TSA (1 μM). However, TSA did not induce the secretion of lysine-mutated APE1/Ref-1 (K6R/K7R). TSA also caused nuclear to cytoplasmic translocation of APE1/Ref-1. Taken together, these findings suggest that APE1/Ref-1 is a protein whose secretion is governed by lysine acetylation.

  16. Histone deacetylases and their inhibitors: molecular mechanisms and therapeutic implications in diabetes mellitus

    OpenAIRE

    Xiaojie Wang; Xinbing Wei; Qi Pang; Fan Yi

    2012-01-01

    Epigenetic mechanisms such as DNA methylation, histone modification and microRNA changes have been shown to be important for the regulation of cellular functions. Among them, histone deacetylases (HDACs) are enzymes that balance the acetylation activities of histone acetyltransferases in chromatin remodeling and play essential roles in gene transcription to regulate cell proliferation, migration and death. Recent studies indicate that HDACs are promising drug targets for a wide range of disea...

  17. Progress in clinical trial of histone deacetylase (HDAC) inhibitors for non-small cell lung cancers

    Institute of Scientific and Technical Information of China (English)

    Xingsheng Hu; Lin Wang; Lin Lin; Yuankai Shi

    2014-01-01

    Histone deacetylase (HDAC) inhibitors, which represent a structural y diverse group of molecules, have emerged as a novel therapeutic class of molecules with significant anticancer potential. Vorinostat and romidepsin, known as the first generation of HDAC inhibitors, were approved in the United States for the treatment of T-celllymphomas. Preliminary activity of HDAC inhibitors has also been observed in non-smal celllung cancer (NSCLC) in combination with the existing treatment regimens, of which is the focus of the current review.

  18. Histone Deacetylase Inhibitors Stimulate Dedifferentiation of Human Breast Cancer Cells through WNT/β-catenin Signaling

    OpenAIRE

    2012-01-01

    Recent studies have shown that differentiated cancer cells can de-differentiate into cancer stem cells (CSCs) although to date no studies have reported whether this transition is influenced by systemic anti-cancer agents. Valproic acid (VA) is a histone deacetylase (HDAC) inhibitor that promotes self renewal and expansion of hematopietic stem cells and facilitates the generation of induced pluripotent stem cells from somatic cells and is currently being investigated in breast cancer clinical ...

  19. SQSTM1/p62 interacts with HDAC6 and regulates deacetylase activity.

    Directory of Open Access Journals (Sweden)

    Jin Yan

    Full Text Available Protein aggregates can form in the cytoplasm of the cell and are accumulated at aggresomes localized to the microtubule organizing center (MTOC where they are subsequently degraded by autophagy. In this process, aggregates are engulfed into autophagosomes which subsequently fuse with lysosomes for protein degradation. A member of the class II histone deacetylase family, histone deacetylase 6(HDAC6 has been shown to be involved in both aggresome formation and the fusion of autophagosomes with lysosomes making it an attractive target to regulate protein aggregation. The scaffolding protein sequestosome 1(SQSTM1/p62 has also been shown to regulate accumulation and autophagic clearance of protein aggregates. Recent studies have revealed colocalization of HDAC6 and p62 to ubiquitinated mitochondria, as well as, ubiquitinated protein aggregates associated with the E3 ubiquitin ligase TRIM50. HDAC6 deacetylase activity is required for aggresome formation and can be regulated by protein interaction with HDAC6. Due to their colocalization at ubiquitinated protein aggregates, we sought to examine if p62 specifically interacted with HDAC6 and if so, if this interaction had any effect on HDAC6 activity and/or the physiological function of cortactin-F-actin assembly. We succeeded in identifying and mapping the direct interaction between HDAC6 and p62. We further show that this interaction regulates HDAC6 deacetylase activity. Data are presented demonstrating that the absence of p62 results in hyperactivation of HDAC6 and deacetylation of α-tubulin and cortactin. Further, upon induction of protein misfolding we show that p62 is required for perinuclear co-localization of cortactin-F-actin assemblies. Thus, our findings indicate that p62 plays a key role in regulating the recruitment of F-actin network assemblies to the MTOC, a critical cellular function that is required for successful autophagic clearance of protein aggregates.

  20. Evaluation of histone deacetylase inhibitors (HDACi) as therapeutic leads for human African trypanosomiasis (HAT).

    Science.gov (United States)

    Carrillo, Angela K; Guiguemde, W Armand; Guy, R Kiplin

    2015-08-15

    Two of the histone deacetylases, TbDAC1 and TbDAC3, have been reported to be essential genes in trypanosomes. Therefore, we tested the activity of a panel of human histone deacetylase inhibitors (HDACi) for their ability to block proliferation of Trypanosoma brucei brucei. Among the HDACi's, the hydroxamic acid derivatives panobinostat and belinostat exhibited potency that appeared to make them viable candidates for development due to their reported pharmacokinetic characteristics. However, cellular pharmacodynamic analysis demonstrated that these drugs were unable to kill cultured parasites at exposures seen in patients at their tolerated doses and additionally failed to show any synergistic effects in combination with pentamidine, suramin, melarsoprol, or nifurtimox. Analysis of the potency of the entire HDACi panel revealed no correlations between potency against any human HDAC isoform and inhibition of T. brucei proliferation, suggesting that the trypanosome histone deacetylases possess a unique specificity. These studies confirmed that HDAC inhibitors have potential as leads against human African trypanosomiasis but that none of the current clinical candidates can be directly repurposed. Therefore, development of HDACi's with appropriate specificity and potency may be a viable route to a new class of anti-trypanosomal drugs.

  1. Class I histone deacetylases regulate p53/NF-κB crosstalk in cancer cells.

    Science.gov (United States)

    Schäfer, Claudia; Göder, Anja; Beyer, Mandy; Kiweler, Nicole; Mahendrarajah, Nisintha; Rauch, Anke; Nikolova, Teodora; Stojanovic, Natasa; Wieczorek, Martin; Reich, Thomas R; Tomicic, Maja T; Linnebacher, Michael; Sonnemann, Jürgen; Dietrich, Sascha; Sellmer, Andreas; Mahboobi, Siavosh; Heinzel, Thorsten; Schneider, Günter; Krämer, Oliver H

    2017-01-01

    The transcription factors NF-κB and p53 as well as their crosstalk determine the fate of tumor cells upon therapeutic interventions. Replicative stress and cytokines promote signaling cascades that lead to the co-regulation of p53 and NF-κB. Consequently, nuclear p53/NF-κB signaling complexes activate NF-κB-dependent survival genes. The 18 histone deacetylases (HDACs) are epigenetic modulators that fall into four classes (I-IV). Inhibitors of histone deacetylases (HDACi) become increasingly appreciated as anti-cancer agents. Based on their effects on p53 and NF-κB, we addressed whether clinically relevant HDACi affect the NF-κB/p53 crosstalk. The chemotherapeutics hydroxyurea, etoposide, and fludarabine halt cell cycle progression, induce DNA damage, and lead to DNA fragmentation. These agents co-induce p53 and NF-κB-dependent gene expression in cell lines from breast and colon cancer and in primary chronic lymphatic leukemia (CLL) cells. Using specific HDACi, we find that the class I subgroup of HDACs, but not the class IIb deacetylase HDAC6, are required for the hydroxyurea-induced crosstalk between p53 and NF-κB. HDACi decrease the basal and stress-induced expression of p53 and block NF-κB-regulated gene expression. We further show that class I HDACi induce senescence in pancreatic cancer cells with mutant p53.

  2. CHD4 Is a Peripheral Component of the Nucleosome Remodeling and Deacetylase Complex.

    Science.gov (United States)

    Low, Jason K K; Webb, Sarah R; Silva, Ana P G; Saathoff, Hinnerk; Ryan, Daniel P; Torrado, Mario; Brofelth, Mattias; Parker, Benjamin L; Shepherd, Nicholas E; Mackay, Joel P

    2016-07-22

    Chromatin remodeling enzymes act to dynamically regulate gene accessibility. In many cases, these enzymes function as large multicomponent complexes that in general comprise a central ATP-dependent Snf2 family helicase that is decorated with a variable number of regulatory subunits. The nucleosome remodeling and deacetylase (NuRD) complex, which is essential for normal development in higher organisms, is one such macromolecular machine. The NuRD complex comprises ∼10 subunits, including the histone deacetylases 1 and 2 (HDAC1 and HDAC2), and is defined by the presence of a CHD family remodeling enzyme, most commonly CHD4 (chromodomain helicase DNA-binding protein 4). The existing paradigm holds that CHD4 acts as the central hub upon which the complex is built. We show here that this paradigm does not, in fact, hold and that CHD4 is a peripheral component of the NuRD complex. A complex lacking CHD4 that has HDAC activity can exist as a stable species. The addition of recombinant CHD4 to this nucleosome deacetylase complex reconstitutes a NuRD complex with nucleosome remodeling activity. These data contribute to our understanding of the architecture of the NuRD complex.

  3. Thermodynamics of ligand binding to histone deacetylase like amidohydrolase from Bordetella/Alcaligenes.

    Science.gov (United States)

    Meyners, Christian; Baud, Matthias G J; Fuchter, Matthew J; Meyer-Almes, Franz-Josef

    2014-03-01

    Thermodynamic studies on ligand-protein binding have become increasingly important in the process of drug design. In combination with structural data and molecular dynamics simulations, thermodynamic studies provide relevant information about the mode of interaction between compounds and their target proteins and therefore build a sound basis for further drug optimization. Using the example of histone deacetylases (HDACs), particularly the histone deacetylase like amidohydrolase (HDAH) from Bordetella/Alcaligenes, a novel sensitive competitive fluorescence resonance energy transfer-based binding assay was developed and the thermodynamics of interaction of both fluorescent ligands and inhibitors to histone deacetylase like amidohydrolase were investigated. The assay consumes only small amounts of valuable target proteins and is suitable for fast kinetic and mechanistic studies as well as high throughput screening applications. Binding affinity increased with increasing length of aliphatic spacers (n = 4-7) between the hydroxamate moiety and the dansyl head group of ligand probes. Van't Hoff plots revealed an optimum in enthalpy contribution to the free energy of binding for the dansyl-ligand with hexyl spacer. The selectivity in the series of dansyl-ligands against human class I HDAC1 but not class II HDACs 4 and 6 increased with the ratio of ΔH(0)/ΔG(0). The data clearly emphasize the importance of thermodynamic signatures as useful general guidance for the optimization of ligands or rational drug design.

  4. SCARECROW-LIKE15 interacts with HISTONE DEACETYLASE19 and is essential for repressing the seed maturation programme

    Science.gov (United States)

    Gao, Ming-Jun; Li, Xiang; Huang, Jun; Gropp, Gordon M.; Gjetvaj, Branimir; Lindsay, Donna L.; Wei, Shu; Coutu, Cathy; Chen, Zhixiang; Wan, Xiao-Chun; Hannoufa, Abdelali; Lydiate, Derek J.; Gruber, Margaret Y.; Chen, Z. Jeffrey; Hegedus, Dwayne D.

    2015-01-01

    Epigenetic regulation of gene expression is critical for controlling embryonic properties during the embryo-to-seedling phase transition. Here we report that a HISTONE DEACETYLASE19 (HDA19)-associated regulator, SCARECROW-LIKE15 (SCL15), is essential for repressing the seed maturation programme in vegetative tissues. SCL15 is expressed in and GFP-tagged SCL15 predominantly localizes to, the vascular bundles particularly in the phloem companion cells and neighbouring specialized cells. Mutation of SCL15 leads to a global shift in gene expression in seedlings to a profile resembling late embryogenesis in seeds. In scl15 seedlings, many genes involved in seed maturation are markedly derepressed with concomitant accumulation of seed 12S globulin; this is correlated with elevated levels of histone acetylation at a subset of seed-specific loci. SCL15 physically interacts with HDA19 and direct targets of HDA19–SCL15 association are identified. These studies reveal that SCL15 acts as an HDA19-associated regulator to repress embryonic traits in seedlings. PMID:26129778

  5. Plant Polyphenols and Oxidative Metabolites of the Herbal Alkenylbenzene Methyleugenol Suppress Histone Deacetylase Activity in Human Colon Carcinoma Cells

    Directory of Open Access Journals (Sweden)

    Isabel Anna Maria Groh

    2013-01-01

    Full Text Available Evidence has been provided that diet and environmental factors directly influence epigenetic mechanisms associated with cancer development in humans. The inhibition of histone deacetylase (HDAC activity and the disruption of the HDAC complex have been recognized as a potent strategy for cancer therapy and chemoprevention. In the present study, we investigated whether selected plant constituents affect HDAC activity or HDAC1 protein status in the human colon carcinoma cell line HT29. The polyphenols (−-epigallocatechin-3-gallate (EGCG and genistein (GEN as well as two oxidative methyleugenol (ME metabolites were shown to inhibit HDAC activity in intact HT29 cells. Concomitantly, a significant decrease of the HDAC1 protein level was observed after incubation with EGCG and GEN, whereas the investigated ME metabolites did not affect HDAC1 protein status. In conclusion, dietary compounds were found to possess promising HDAC-inhibitory properties, contributing to epigenetic alterations in colon tumor cells, which should be taken into account in further risk/benefit assessments of polyphenols and alkenylbenzenes.

  6. Histone deacetylase inhibitor pracinostat in doublet therapy: a unique strategy to improve therapeutic efficacy and to tackle herculean cancer chemoresistance.

    Science.gov (United States)

    Ganai, Shabir Ahmad

    2016-09-01

    Context Histone deacetylase inhibitors (HDACi) have shown promising results in neurodegeneration and cancer. Hydroxamate HDACi, including vorinostat, have shown encouraging results in haematological malignancies, but the poor pharmacokinetic of these inhibitors leads to insufficient tumour concentration limiting their application against solid malignancies. Objective This article deals with novel HDAC inhibitor pracinostat (SB939) and delineates its therapeutic role in solid and haematological malignancies. The article provides rigorous details about the underlying molecular mechanisms modulated by pracinostat to exert cytotoxic effect. The article further highlights the doublet therapy that may be used to tackle monotonous cancer chemoresistance. Methods Both old and the latest literature on pracinostat was retrieved from diverse sources, such as PubMed, Science Direct, Springer Link, general Google search using both pracinostat and SB939 keywords in various ways: after thorough evaluation the topic which can fulfil the current gap was chosen. Results Pracinostat shows potent anticancer activity against both solid and haematological malignancies compared to the FDA-approved drug vorinostat. This marvellous inhibitor has better physicochemical, pharmaceutical and pharmacokinetic properties than the defined inhibitor vorinostat. Pracinostat has  >100-fold more affinity towards HDACs compared to other zinc-dependent metalloenzymes and shows maximum efficacy when used in doublet therapy. Conclusion Pracinostat shows potent anticancer activity even against therapeutically challenging cancers when used in doublet therapy. However, the triplet combination studies of the defined inhibitor that may prove even more beneficial are still undone, emphasizing the desperate need of further research in the defined gap.

  7. 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.

  8. A novel chitin-binding protein from Moringa oleifera seed with potential for plant disease control.

    Science.gov (United States)

    Gifoni, Juliana M; Oliveira, José T A; Oliveira, Hermogenes D; Batista, Adelina B; Pereira, Mirella L; Gomes, Antoniella S; Oliveira, Henrique P; Grangeiro, Thalles B; Vasconcelos, Ilka M

    2012-01-01

    A thermostable chitin-binding protein (14.3 kDa) with antifungal activity was isolated from Moringa oleifera seeds by affinity chromatography on chitin followed by ion exchange chromatography. NH(2-) CPAIQRCCQQLRNIQPPCRCCQ (Mo-CBP3) is a glycoprotein with 2.5% sugar, pI 10.8, without hemagglutination, chitinase or beta-glucanase activities. Mo-CBP3 possesses in vitro antifungal activity against the phytopathogenicfungi Fusarium solani, F. oxysporum, Colletotrichum musae and C. gloesporioides. Contrarily, Mo-CBP3 did not affect Pythium oligandrum, an oomycete. At 0.05 mg/ml, Mo-CBP3 showed to be fungistatic against F. solani, but at 0.1 mg/ml Mo-CBP3 behaved as a potent fungicidal agent as it inhibited both the spore germination and mycelial growth of F. solani. Surprisingly, the effect of Mo-CBP3 against spore germination was observed even when the protein was heated at 100 degrees C for 1 h or pretreated with 0.15M N-acetyl-D-glucosamine. Mo-CBP3 inhibited the glucose-stimulated acidification of the incubation medium by F. solani. This is apparently caused by structural plasma membrane disarrangement induced by Mo-CBP3. Altogether, these results suggest that Mo-CBP3 might be involved in plant defense mechanisms and could be used as potential antifungal agent for controlling fungal pathogens in plants.

  9. Adsorption of Methylene Blue, Bromophenol Blue, and Coomassie Brilliant Blue by α-chitin nanoparticles

    Directory of Open Access Journals (Sweden)

    Solairaj Dhananasekaran

    2016-01-01

    Full Text Available Expelling of dyestuff into water resource system causes major thread to the environment. Adsorption is the cost effective and potential method to remove the dyes from the effluents. Therefore, an attempt was made to study the adsorption of dyestuff (Methylene Blue (MB, Bromophenol Blue (BPB and Coomassie Brilliant Blue (CBB by α-chitin nanoparticles (CNP prepared from Penaeus monodon (Fabricius, 1798 shell waste. On contrary to the most recognizable adsorption studies using chitin, this is the first study using unique nanoparticles of ⩽50 nm used for the dye adsorption process. The results showed that the adsorption process increased with increase in the concentration of CNP, contact time and temperature with the dyestuff, whereas the adsorption process decreased with increase in the initial dye concentration and strong acidic pH. The results from Fourier transform infrared (FTIR spectroscopy confirmed that the interaction between dyestuff and CNP involved physical adsorption. The adsorption process obeys Langmuir isotherm (R2 values were 0.992, 0.999 and 0.992 for MB, BPB and CBB, and RL value lies between 0 and 1 for all the three dyes and pseudo second order kinetics (R2 values were 0.996, 0.999 and 0.996 for MB, BPB and CBB more effectively. The isotherm and kinetic models confirmed that CNP can be used as a suitable adsorbent material for the removal of dyestuff from effluents.

  10. Cloning and sequence analysis of chitin synthase gene fragments of Demodex mites.

    Science.gov (United States)

    Zhao, Ya-e; Wang, Zheng-hang; Xu, Yang; Xu, Ji-ru; Liu, Wen-yan; Wei, Meng; Wang, Chu-ying

    2012-10-01

    To our knowledge, few reports on Demodex studied at the molecular level are available at present. In this study our group, for the first time, cloned, sequenced and analyzed the chitin synthase (CHS) gene fragments of Demodex folliculorum, Demodex brevis, and Demodex canis (three isolates from each species) from Xi'an China, by designing specific primers based on the only partial sequence of the CHS gene of D. canis from Japan, retrieved from GenBank. Results show that amplification was successful only in three D. canis isolates and one D. brevis isolate out of the nine Demodex isolates. The obtained fragments were sequenced to be 339 bp for D. canis and 338 bp for D. brevis. The CHS gene sequence similarities between the three Xi'an D. canis isolates and one Japanese D. canis isolate ranged from 99.7% to 100.0%, and those between four D. canis isolates and one D. brevis isolate were 99.1%-99.4%. Phylogenetic trees based on maximum parsimony (MP) and maximum likelihood (ML) methods shared the same clusters, according with the traditional classification. Two open reading frames (ORFs) were identified in each CHS gene sequenced, and their corresponding amino acid sequences were located at the catalytic domain. The relatively conserved sequences could be deduced to be a CHS class A gene, which is associated with chitin synthesis in the integument of Demodex mites.

  11. 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.

  12. 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...... than that in the wild type., whereas that in the ChsB/G strain was 188% higher. During batch cultivation, inseparable clumps were formed in the wild-type strain., while no or fewer large inseparable clumps existed in the cultivations of the ChsB/G and CM101 strains. The alpha-amylase productivity...... an important role for chsB in branching. However, the pattern of branching responded very slowly to the change in transcription, and increased branching did not affect alpha-amylase productivity. alpha-Amylase residing in the cell wall was stained by immunofluorescence, and the relationship between tip number...

  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. Histone Deacetylase Inhibition and Dietary Short-Chain Fatty Acids

    OpenAIRE

    Licciardi, Paul V.; Ververis, Katherine; Karagiannis, Tom C.

    2011-01-01

    Changes in diet can also have dramatic effects on the composition of gut microbiota. Commensal bacteria of the gastrointestinal tract are critical regulators of health and disease by protecting against pathogen encounter whilst also maintaining immune tolerance to certain allergens. Moreover, consumption of fibre and vegetables typical of a non-Western diet generates substantial quantities of short-chain fatty acids (SCFAs) which have potent anti-inflammatory properties. Dietary interventions...

  15. 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.

  16. Distribution of Calcium and Chitin in the Tardigrade Feeding Apparatus in Relation to its Function and Morphology.

    Science.gov (United States)

    Guidetti, Roberto; Bonifacio, Alois; Altiero, Tiziana; Bertolani, Roberto; Rebecchi, Lorena

    2015-08-01

    The cuticular portion of the tardigrade feeding apparatus is a complex structure that can be schematically divided into four parts: a buccal ring, a buccal tube, a stylet system (formed by two piercing stylets, each within a stylet coat, and two stylet supports), and the lining of a myoepithelial sucking pharynx. To better understand the function and evolution of the feeding apparatus, the morpho-functional traits and chemical composition of the structures forming the feeding apparatuses of eight different species of tardigrades were analyzed. These eight species are representative of almost all main phylogenetic lineages of the phylum. The calcium and chitin in the feeding apparatus were examined by light microscopy, scanning electron microscopy, confocal laser scanning microscopy, energy dispersive X-ray spectroscopy, and Raman microspectroscopy (Raman). In all species, the feeding apparatus had been subjected to biomineralization due to CaCO3 encrustations organized in the crystalline form of aragonite. Aragonite and chitin are present in different concentrations in the feeding apparatus according to the structures and species considered. Generally, where the structures are rigid there is more aragonite than chitin, and vice versa. The buccal tube and piercing stylets are rich in calcium, with the piercing stylets apparently composed exclusively of aragonite. In eutardigrades, chitin is in higher concentration in the structures subject to higher mechanical stresses, such as the crests of the buccal crown and the condyles of the stylet furca.

  17. Kinetics of N-Deacetylation of Chitin Extracted from Shrimp Shells Collected from Coastal Area of Morocco

    Directory of Open Access Journals (Sweden)

    Hammou Ahlafi

    2013-02-01

    Full Text Available Chitosan was obtained from the alkaline N-deacetylation of -chitin, derived from shrimp shells (SS collected from the Moroccan coast. Effects of temperature, NaOH concentration and reaction time on the kinetics of deacetylation were studied. The degree of deacetylation (DD = 75% was obtained at T = 120 °C and CNaOH = 12N in a single step for 6h. It was found, from FTIR studies, that the removal of acetyl groups from chitin occur very fast for the reaction time t < 180 min and then becomes constant after, revealing two steps in the deacetylation of chitin following a first-order kinetics for each of them. The second step is considered the limiting step that has, in the temperature range of 25 – 120 °C and maintained CNaOH = 12N, a low apparent rate constant. The activation energy of this step is about 48.76 kJ/mol. The biopolymer (Chitin and chitosan produced were characterized by X-ray diffraction.

  18. 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.

    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

  19. 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

  20. 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.

  1. Resistance mutation conserved between insects and mites unravels the benzoylurea insecticide mode of action on chitin biosynthesis.

    Science.gov (United States)

    Douris, Vassilis; Steinbach, Denise; Panteleri, Rafaela; Livadaras, Ioannis; Pickett, John Anthony; Van Leeuwen, Thomas; Nauen, Ralf; Vontas, John

    2016-12-20

    Despite the major role of chitin biosynthesis inhibitors such as benzoylureas (BPUs) in the control of pests in agricultural and public health for almost four decades, their molecular mode of action (MoA) has in most cases remained elusive. BPUs interfere with chitin biosynthesis and were thought to interact with sulfonylurea receptors that mediate chitin vesicle transport. Here, we uncover a mutation (I1042M) in the chitin synthase 1 (CHS1) gene of BPU-resistant Plutella xylostella at the same position as the I1017F mutation reported in spider mites that confers etoxazole resistance. Using a genome-editing CRISPR/Cas9 approach coupled with homology-directed repair (HDR) in Drosophila melanogaster, we introduced both substitutions (I1056M/F) in the corresponding fly CHS1 gene (kkv). Homozygous lines bearing either of these mutations were highly resistant to etoxazole and all tested BPUs, as well as buprofezin-an important hemipteran chitin biosynthesis inhibitor. This provides compelling evidence that BPUs, etoxazole, and buprofezin share in fact the same molecular MoA and directly interact with CHS. This finding has immediate effects on resistance management strategies of major agricultural pests but also on mosquito vectors of serious human diseases such as Dengue and Zika, as diflubenzuron, the standard BPU, is one of the few effective larvicides in use. The study elaborates on how genome editing can directly, rapidly, and convincingly elucidate the MoA of bioactive molecules, especially when target sites are complex and hard to reconstitute in vitro.

  2. Chitin synthase 1 (Chs1) gene sequences of Microsporum equinum and Trichophyton equinum.

    Science.gov (United States)

    Kano, R; Aihara, S; Nakamura, Y; Watanabe, S; Hasegawa, A

    2001-01-05

    Chitin synthase 1 (Chs1) genes from Microsporum equinum and Trichophyton equinum were compared with those of the other dermatophytes. The Chs1 nucleotide sequences of these dermatophytes from horses showed more than 80% similarity to those of Arthroderma benhamiae, A. fulvum, A. grubyi, A. gypseum, A. incruvatum, A. otae, A. simii, A. vanbreuseghemii, Epidermophyton floccosum, T. mentagrophytes var. interdigitale (T. interdigitale), T. rubrum and T. violaceum. Especially high degree of nucleotide sequence similarity of more than 99% was noted between the Chs1 gene fragments of M. equinum and A. otae, and those of T. equinum, T. interdigitale and A. vanbreuseghemii, respectively. The phylogenetic analysis of their sequences revealed that M. equinum was genetically very close to A. otae and T. equinum to A. vanbreuseghemii. A molecular analysis of Chs1 genes will provide useful information for the genetic relatedness of M. equinum and T. equinum and confirm the value of DNA sequencing in identification of these two dermatophytes.

  3. 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 (Pretrogradation. The CNWs could be used as a new inhibitor of starch retrogradation to develop starch-based food with longer shelf life.

  4. 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.

  5. 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

    The direct conversion of chitin biomass to 5-hydroxymethylfurfural (5-HMF) in ZnCl2 aqueous solution was studied systemically. D-Glucosamine (GlcNH2) was chosen as the model compound to investigate the reaction, and 5-HMF could be obtained in 21.9% yield with 99% conversion of GlcNH2. Optimization...... to be 67 wt.% ZnCl2 aqueous solution, at 120 °C without co-catalyst. The reactions were further studied by in situ NMR, and no intermediate or other byproducts, except humins, were observed. Finally, the substrate scope was expanded from GlcNH2 to N-acetyl-D-glucosamine and various chitosan polymers...

  6. Chitinase system of Bacillus circulans WL-12 and importance of chitinase A1 in chitin degradation.

    OpenAIRE

    Watanabe, T.; Oyanagi, W; K. Suzuki; H. Tanaka

    1990-01-01

    Bacillus circulans WL-12, isolated as a yeast cell wall-lytic bacterium, secretes a variety of polysaccharide-degrading enzymes into culture medium. When chitinases of the bacterium were induced with chitin, six distinct chitinase molecules were detected in the culture supernatant. These chitinases (A1, A2, B1, B2, C, and D) showed the following distinct sizes and isoelectric points: Mr 74,000, pI 4.7 (A1); Mr 69,000, pI 4.5 (A2); Mr 38,000, pI 6.6 (B1); Mr 38,000, pI 5.9 (B2); Mr 39,000, pI ...

  7. Recovery of astaxanthin from discharged wastewater during the production of chitin

    Science.gov (United States)

    Chen, Xiaolin; Yang, Shengfeng; Xing, Ronge; Yu, Huahua; Liu, Song; Li, Pengcheng

    2012-06-01

    In this paper, studies were carried out to extract astaxanthin from discharged wastewater during the production of chitin and to reveal the scavenging effect of the obtained pigment on 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical. Different ratios of dichloromethane/methanol (V/V) were used to extract astaxanthin. When the ratio of dichloromethane/methanol was 2:8 and the ratio between the mixed organic solvent (dichloromethane/methanol, 2:8, V/V) and wastewater was 1:1, the highest yield of pigment was obtained (8.4 mg/50 mL). The concentration of free astaxanthin in the obtained pigment analyzed by HPLC was 30.02%. The obtained pigment possessed strong scavenging ability on DPPH radical and IC50 was 0.84mg/ml.

  8. Preparation of aligned porous chitin nanowhisker foams by directional freeze-casting technique.

    Science.gov (United States)

    Zhou, Yiming; Fu, Shiyu; Pu, Yunqiao; Pan, Shaobo; Ragauskas, Arthur J

    2014-11-04

    Structured biofoams with aligned porous structures were fabricated from nanosized chitin by employing a directional freeze-casting technique. The effects of the freezing conditions and slurry formulation on nanochitin foam morphology were investigated. The morphology of obtained foams was characterized using scanning electron microscopy (SEM). It was found that the pore structure of the obtained foams was a likewise of the ice crystals formed during the directional freezing. The results indicate that directional freeze-casting protocol can significantly influence the morphological features and microstructures of the obtained biofoams which could have numerous applications, including engineered carriers, scaffolds, filters and specifically as a template for potential multi-layered composites after infusion with a second phase.

  9. 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...... binding is mediated by the unique stereochemical arrangement of oppositely charged amino and carboxy groups. Conjugation of oligosaccharides to fluorophores or gold nanoparticles enables direct and rapid imaging of homogalacturonan and chitosan with unprecedented precision in diverse plant, fungal...... and animal systems. We demonstrated their potential for providing new biological insights by using them to study homogalacturonan processing during Arabidopsis thaliana root cap development and by analyzing sites of chitosan deposition in fungal cell walls and arthropod exoskeletons....

  10. 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.

  11. 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.

  12. Cloning and sequence analysis of chitin synthase gene fragments of Demodex mites

    Institute of Scientific and Technical Information of China (English)

    Ya-e ZHAO; Zheng-hang WANG; Yang XU; Ji-ru XU; Wen-yan LIU; Meng WEI; Chu-ying WANG

    2012-01-01

    To our knowledge,few reports on Demodex studied at the molecular level are available at present.In this study our group,for the first time,cloned,sequenced and analyzed the chitin synthase (CHS) gene fragments of Demodex folliculorum,Demodex brevis,and Demodex canis (three isolates from each species) from Xi'an China,by designing specific primers based on the only partial sequence of the CHS gene of D.canis from Japan,retrieved from GenBank.Results show that amplification was successful only in three D.canis isolates and one D.brevis isolate out of the nine Demodex isolates.The obtained fragments were sequenced to be 339 bp for D.canis and 338 bp for D.brevis.The CHS gene sequence similarities between the three Xi'an D.canis isolates and one Japanese D.canis isolate ranged from 99.7% to 100.0%,and those between four D.canis isolates and one D.brevis isolate were 99.1%-99.4%.Phylogenetic trees based on maximum parsimony (MP) and maximum likelihood (ML) methods shared the same clusters,according with the traditional classification.Two open reading frames (ORFs) were identified in each CHS gene sequenced,and their corresponding amino acid sequences were located at the catalytic domain.The relatively conserved sequences could be deduced to be a CHS class A gene,which is associated with chitin synthesis in the integument of Demodex mites.

  13. Substrate recognition of N,N'-diacetylchitobiose deacetylase from Pyrococcus horikoshii.

    Science.gov (United States)

    Nakamura, Tsutomu; Yonezawa, Yasushige; Tsuchiya, Yuko; Niiyama, Mayumi; Ida, Kurumi; Oshima, Maki; Morita, Junji; Uegaki, Koichi

    2016-09-01

    Enzymes of carbohydrate esterase (CE) family 14 catalyze hydrolysis of N-acetyl groups at the non-reducing end of the N-acetylglucosamine (GlcNAc) residue of chitooligosaccharides or related compounds. N,N'-diacetylchitobiose deacetylase (Dac) belongs to the CE-14 family and plays a role in the chitinolytic pathway in archaea by deacetylating N,N'-diacetylchitobiose (GlcNAc2), which is the end product of chitinase. In this study, we revealed the structural basis of reaction specificity in CE-14 deacetylases by solving a crystal structure of Dac from Pyrococcus horikoshii (Ph-Dac) in complex with a novel reaction intermediate analog. We developed 2-deoxy-2-methylphosphoramido-d-glucose (MPG) as the analog of the tetrahedral oxyanion intermediate of the monosaccharide substrate GlcNAc. The crystal structure of Ph-Dac in complex with MPG demonstrated that Arg92, Asp115, and His152 side chains interact with hydroxyl groups of the glucose moiety of the non-reducing-end GlcNAc residue. The amino acid residues responsible for recognition of the MPG glucose moiety are spatially conserved in other CE-14 deacetylases. Molecular dynamics simulation of the structure of the Ph-Dac-GlcNAc2 complex indicated that the reducing GlcNAc residue is placed in a large intermolecular cleft and is not involved with specific interactions with the enzyme. This observation was consistent with results indicating that Ph-Dac displayed similar kinetic parameters for both GlcNAc and GlcNAc2. This study provides the structural basis of reaction-site specificity of Dac and related CE-14 enzymes.

  14. Histone deacetylase inhibitors relieve morphine resistance in neuropathic pain after peripheral nerve injury.

    Science.gov (United States)

    Uchida, Hitoshi; Matsushita, Yosuke; Araki, Kohei; Mukae, Takehiro; Ueda, Hiroshi

    2015-08-01

    Neuropathic pain is often insensitive to morphine. Our previous study has demonstrated that neuron-restrictive silencer factor represses mu opioid receptor (MOP) gene expression in the dorsal root ganglion (DRG) via histone hypoacetylation-mediated mechanisms after peripheral nerve injury, thereby causing loss of peripheral morphine analgesia. Here, we showed that histone deacetylase (HDAC) inhibitors, such as trichostatin A and valproic acid, restored peripheral and systemic morphine analgesia in neuropathic pain. Also, these agents blocked nerve injury-induced MOP down-regulation in the DRG. These results suggest that HDAC inhibitors could serve as adjuvant analgesics to morphine for the management of neuropathic pain.

  15. Non-isotopic dual parameter competition assay suitable for high-throughput screening of histone deacetylases.

    Science.gov (United States)

    Riester, Daniel; Hildmann, Christian; Haus, Patricia; Galetovic, Antonia; Schober, Andreas; Schwienhorst, Andreas; Meyer-Almes, Franz-Josef

    2009-07-01

    Histone deacetylases reside among the most important and novel target classes in oncology. Selective lead structures are intensively developed to improve efficacy and reduce adverse effects. The common assays used so far to identify new lead structures suffer from many false positive hits due to auto-fluorescence of compounds or triggering undesired signal transduction pathways. These drawbacks are eliminated by the dual parameter competition assay reported in this study. The assay involves a new fluorescent inhibitor probe that shows an increase in both, fluorescence anisotropy and fluorescence lifetime upon binding to the enzyme. The assay is well suited for high-throughput screening.

  16. Lysine deacetylase inhibition prevents diabetes by chromatin-independent immunoregulation and β-cell protection

    DEFF Research Database (Denmark)

    Christensen, Dan Ploug; Gysemans, Conny; Lundh, Morten

    2014-01-01

    Type 1 diabetes is due to destruction of pancreatic β-cells. Lysine deacetylase inhibitors (KDACi) protect β-cells from inflammatory destruction in vitro and are promising immunomodulators. Here we demonstrate that the clinically well-tolerated KDACi vorinostat and givinostat revert diabetes...... was blocked. These effects were associated with NF-κB subunit p65 hyperacetylation. Taken together, these data provide a rationale for clinical trials of safety and efficacy of KDACi in patients with autoimmune disease such as type 1 diabetes....

  17. Transcriptional activation of NAD{sup +}-dependent protein deacetylase SIRT1 by nuclear receptor TLX

    Energy Technology Data Exchange (ETDEWEB)

    Iwahara, Naotoshi [Department of Pharmacology, Sapporo Medical University, Sapporo 060-8556 (Japan); Hisahara, Shin; Hayashi, Takashi [Department of Pharmacology, Sapporo Medical University, Sapporo 060-8556 (Japan); Department of Neurology, Sapporo Medical University, Sapporo 060-8556 (Japan); Horio, Yoshiyuki, E-mail: horio@sapmed.ac.jp [Department of Pharmacology, Sapporo Medical University, Sapporo 060-8556 (Japan)

    2009-09-04

    An orphan nuclear receptor TLX is a transcriptional repressor that promotes the proliferation and self-renewal of neural precursor cells (NPCs). SIRT1, an NAD{sup +}-dependent protein deacetylase, is highly expressed in the NPCs and participates in neurogenesis. Here, we found that TLX colocalized with SIRT1 and knockdown of TLX by small interfering RNAs decreased SIRT1 levels in NPCs. TLX increased the SIRT1 expression by binding to the newly identified TLX-activating element in the SIRT1 gene promoter in HEK293 cells. Thus, TLX is an inducer of SIRT1 and may contribute to neurogenesis both as a transactivator and as a repressor.

  18. Focus on acetylation: the role of histone deacetylase inhibitors in cancer therapy and beyond.

    Science.gov (United States)

    Konstantinopoulos, Panagiotis A; Karamouzis, Michalis V; Papavassiliou, Athanasios G

    2007-05-01

    Reversal of tumorigenic epigenetic alterations is an exciting strategy for anticancer drug development. Pharmacologic inhibition of histone deacetylases (HDACs) induces differentiation, proliferation arrest and apoptosis of cancer cells. In addition to their effects on histones, HDAC inhibitors increase the acetylation level of several non-histone proteins, such as transcription factors, cytoskeletal proteins and molecular chaperones, which are crucial in tumorigenesis. Most importantly, the therapeutic potential of HDAC inhibitors goes well beyond carcinogenesis and may include neurodegenerative and inflammatory disorders. This editorial discusses the implication of HDACs in carcinogenesis, the molecular basis of the selectivity of HDAC inhibitors and their possible therapeutic role in non-malignant pathologic conditions.

  19. The regulatory effects of radiation and histone deacetylase inhibitor on liver cancer cell cycle

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sung Ho; Choi, Hyung Seok; Jang, Dong Gun; Lee, Hong Je; Yang, Seoung Oh [Dept. Nuclear Medicine, Dongnam Institute of Radiological and Medicine Sciences Cancer Center, Busan (Korea, Republic of)

    2013-11-15

    Radiation has been an effective tool for treating cancer for a long time. Radiation therapy induces DNA damage within cancer cells and destroys their ability to reproduce. Radiation therapy is often combined with other treatments, like surgery and chemotherapy. Here, we describe the effects of radiation and histone deacetylase inhibitor, Trichostain A, on cell cycle regulation in hepatoma cells. Results demonstrate that the treatment of radiation TSA induces cell cycle arrest, thereby stimulating cell death in hepatoma cells. In addition, since different cells or tissues have different reactivity to radiation and TSA, these results might be an indicator for the combination therapy with radiation and drugs in diverse cancers.

  20. Histone deacetylase 3 inhibition improves glycaemia and insulin secretion in obese diabetic rats

    DEFF Research Database (Denmark)

    Lundh, Morten; Galbo, Thomas; Poulsen, Steen Seier;

    2015-01-01

    Failure of pancreatic β cells to compensate for insulin resistance is a prerequisite for the development of type 2 diabetes. Sustained elevated circulating levels of free fatty acids and glucose contribute to β-cell failure. Selective inhibition of Histone deacetylase (HDAC)-3 protects pancreatic β...... cells against inflammatory and metabolic insults in vitro. Here we tested the ability of a selective HDAC3 inhibitor, BRD3308, to reduce hyperglycemia and increase insulin secretion in an animal model of type 2 diabetes. At diabetes onset, an ambulatory hyperglycemic clamp was performed. HDAC3......3 as a key therapeutic target for β-cell protection in type 2 diabetes....

  1. A Photoactivatable Platinum(IV) Complex Targeting Genomic DNA and Histone Deacetylases.

    Science.gov (United States)

    Kasparkova, Jana; Kostrhunova, Hana; Novakova, Olga; Křikavová, Radka; Vančo, Ján; Trávníček, Zdeněk; Brabec, Viktor

    2015-11-23

    We report toxic effects of a photoactivatable platinum(IV) complex conjugated with suberoyl-bis-hydroxamic acid in tumor cells. The conjugate exerts, after photoactivation, two functions: activity as both a platinum(II) anticancer drug and histone deacetylase (HDAC) inhibitor in cancer cells. This approach relies on the use of a Pt(IV) pro-drug, acting by two independent mechanisms of biological action in a cooperative manner, which can be selectively photoactivated to a cytotoxic species in and around a tumor, thereby increasing selectivity towards cancer cells. These results suggest that this strategy is a valuable route to design new platinum agents with higher efficacy for photodynamic anticancer chemotherapy.

  2. New benzothiazole/thiazole-containing hydroxamic acids as potent histone deacetylase inhibitors and antitumor agents

    DEFF Research Database (Denmark)

    Thanh Tung, Truong; Oanh, Dao Thi Kim; Dung, Phan Thi Phuong;

    2013-01-01

    Results from clinical studies have demonstrated that inhibitors of histone deacetylase (HDAC) enzymes possess promise for the treatment of several types of cancer. Zolinza(®) (widely known as SAHA) has been approved by the FDA for the treatment of T-cell lymphoma. As a continuity of our ongoing...... research to find novel small molecules to target these important enzymes, we synthesized a series of benzothiazole-containing analogues of SAHA and found several compounds with very potent anticancer cytotoxicity. In this study, three more compounds of this type, including N(1)-(6-chlorobenzo[d]thiazol-2...

  3. Conformationally rigid histone deacetylase inhibitors correct DF508-CFTR protein function

    DEFF Research Database (Denmark)

    Vickers, Chris J.; Olsen, Christian Adam; Hutt, Darren M.

    2011-01-01

    Histone deacetylase (HDAC) inhibitors have shown partial efficacy toward correcting cystic fibrosis transmembrane conductance regulator (CFTR) protein function in ΔF508- CFTR models. While current treatment options for CF generally concentrate on disease symptoms such as management of inflammation...... to formulate a pharmacophore model to describe and enhance the bioactivity of these molecules. Through this study we have developed HDAC inhibitors which improve CFTR trafficking from the endoplasmic reticulum (ER) while ultimately increasing ion conductance across the plasma membrane of a lung epithelial cell...... line expressing ΔF508-CFTR....

  4. Biotin starvation causes mitochondrial protein hyperacetylation and partial rescue by the SIRT3-like deacetylase Hst4p

    DEFF Research Database (Denmark)

    Madsen, Christian Toft; Sylvestersen, Kathrine Beck; Young, Clifford;

    2015-01-01

    cause alterations in cellular respiration and an increase in reactive oxygen species (ROS). These results suggest that Hst4p plays a pivotal role in biotin metabolism and cellular energy homeostasis, and supports that Hst4p is a functional yeast homologue of the sirtuin deacetylase SIRT3. With biotin...... deficiency. Upregulated mitochondrial acetylation sites correlate with the cellular deficiency of the Hst4p deacetylase, and a biotin-starvation-induced accumulation of Hst4p in mitochondria supports a role for Hst4p in lowering mitochondrial acetylation. We show that biotin starvation and knockout of Hst4p...

  5. The new low-toxic histone deacetylase inhibitor S-(2) induces apoptosis in various acute myeloid leukaemia cells.

    Science.gov (United States)

    Cellai, C; Balliu, M; Laurenzana, A; Guandalini, L; Matucci, R; Miniati, D; Torre, E; Nebbioso, A; Carafa, V; Altucci, L; Romanelli, M N; Paoletti, F

    2012-08-01

    Histone deacetylase inhibitors (HDACi) induce tumour cell cycle arrest and/or apoptosis, and some of them are currently used in cancer therapy. Recently, we described a series of powerful HDACi characterized by a 1,4-benzodiazepine (BDZ) ring hybridized with a linear alkyl chain bearing a hydroxamate function as Zn(++)--chelating group. Here, we explored the anti-leukaemic properties of three novel hybrids, namely the chiral compounds (S)-2 and (R)-2, and their non-chiral analogue 4, which were first comparatively tested in promyelocytic NB4 cells. (S)-2 and partially 4--but not (R)-2--caused G0/G1 cell-cycle arrest by up-regulating cyclin G2 and p21 expression and down-regulating cyclin D2 expression, and also apoptosis as assessed by cell morphology and cytofluorimetric assay, histone H2AX phosphorylation and PARP cleavage. Notably, these events were partly prevented by an anti-oxidant. Moreover, novel HDACi prompted p53 and α-tubulin acetylation and, consistently, inhibited HDAC1 and 6 activity. The rank order of potency was (S)-2 > 4 > (R)-2, reflecting that of other biological assays and addressing (S)-2 as the most effective compound capable of triggering apoptosis in various acute myeloid leukaemia (AML) cell lines and blasts from patients with different AML subtypes. Importantly, (S)-2 was safe in mice (up to 150 mg/kg/week) as determined by liver, spleen, kidney and bone marrow histopathology; and displayed negligible affinity for peripheral/central BDZ-receptors. Overall, the BDZ-hydroxamate (S)-2 showed to be a low-toxic HDACi with powerful anti-proliferative and pro-apototic activities towards different cultured and primary AML cells, and therefore of clinical interest to support conventional anti-leukaemic therapy.

  6. Design and synthesis of benzodiazepine analogs as isoform-selective human lysine deacetylase inhibitors.

    Science.gov (United States)

    Reddy, D Rajasekhar; Ballante, Flavio; Zhou, Nancy J; Marshall, Garland R

    2017-02-15

    A comprehensive investigation was performed to identify new benzodiazepine (BZD) derivatives as potent and selective human lysine deacetylase inhibitors (hKDACis). A total of 108 BZD compounds were designed, synthesized and from that 104 compounds were biologically evaluated against human lysine deacetylases (hKDACs) 1, 3 and 8 (class I) and 6 (class IIb). The most active compounds showed mid-nanomolar potencies against hKDACs 1, 3 and 6 and micromolar activity against hKDAC8, while a promising compound (6q) showed selectivity towards hKDAC3 among the different enzyme isoforms. An hKDAC6 homology model, refined by molecular dynamics simulation was generated, and molecular docking studies performed to rationalize the dominant ligand-residue interactions as well as to define structure-activity-relationships. Experimental results confirmed the usefulness of the benzodiazepine moiety as capping group when pursuing hKDAC isoform-selectivity inhibition, suggesting its continued use when designing new hKDACis.

  7. Effect of histone deacetylase inhibitor on proliferation of biliary tract cancer cell lines

    Institute of Scientific and Technical Information of China (English)

    Li-Ning Xu; Xin Wang; Sheng-Quan Zou

    2008-01-01

    AIM: To explore the effect of histone deacetylase inhibitor, trichostatin A (TSA) on the growth of biliary tract cancer cell lines (gallbladder carcinoma cell line and cholangiocarcinoma cell line) in v/vo and in vitro,and to investigate the perspective of histone deacetylase inhibitor in its clinical application.METHODS: The survival rates of gallbladder carcinoma cell line (Mz-ChA-I cell line) and cholangiocarcinoma cell lines (QBC939, KMBC and OZ cell lines) treated with various doses of TSA were detected by methylthiazoy tetrazolium (MTT) assay.A nude mouse model of transplanted gallbladder carcinoma (Mz-ChA-I cell line)was successfully established, and changes in the growth of transplanted tumor after treated with TSAwere measured.RESULTS: TSA could inhibit the proliferation of gallbladder carcinoma cell line (Mz-ChA-I cell line) and cholangiocarcinoma cell lines (QBC939, KMBC and OZ cell lines) in a dose-dependent manner.After the nude mouse model of transplanted gallbladder carcinoma (Mz-ChA-I cell line) was successfully established, the growth of cancer was inhibited in the model, after treated with TSA.CONCLUSION: TSA can inhibit the growth of cholangiocarcinoma and gallbladder carcinoma cell lines in vitro and in vivo.

  8. Histone deacetylases inhibitor trichostatin A modulates the extracellular release of APE1/Ref-1

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Sunga; Lee, Yu Ran; Park, Myoung Soo; Joo, Hee Kyoung; Cho, Eun Jung; Kim, Hyo Shin; Kim, Cuk Seong; Park, Jin Bong [Department of Physiology, School of Medicine, Chungnam National University, Daejeon 301-747 (Korea, Republic of); Irani, Kaikobad [Cardiovascular Institute, University of Pittsburgh, Pittsburgh, PA 15213 (United States); Jeon, Byeong Hwa, E-mail: bhjeon@cnu.ac.kr [Department of Physiology, School of Medicine, Chungnam National University, Daejeon 301-747 (Korea, Republic of)

    2013-06-07

    Highlights: •Trichostatin A (TSA) increased APE1/Ref-1 secretion in HEK293 cells. •Lysine-mutated APE1/Ref-1 (K6R/K7R) was not secreted by TSA. •TSA induced cytoplasmic translocation of APE1/Ref-1. •APE1/Ref-1 is a protein whose secretion is governed by lysine acetylation. -- Abstract: Apurinic/apyrimidinic endonuclease 1/Redox factor-1 (APE1/Ref-1) can be acetylated via post-translational modification. We investigated the effect of an inhibitor of histone deacetylases on the extracellular release of APE1/Ref-1 in HEK293 cells. Trichostatin A (TSA), an inhibitor of histone deacetylases, induced APE1/Ref-1 secretion without changing cell viability. In a fluorescence quantitative assay, the secreted APE1/Ref-1 was estimated to be about 10 ng/mL in response to TSA (1 μM). However, TSA did not induce the secretion of lysine-mutated APE1/Ref-1 (K6R/K7R). TSA also caused nuclear to cytoplasmic translocation of APE1/Ref-1. Taken together, these findings suggest that APE1/Ref-1 is a protein whose secretion is governed by lysine acetylation.

  9. The Role of Histone Deacetylase 6 in Synaptic Plasticity and Memory

    Directory of Open Access Journals (Sweden)

    Sarah Perry

    2017-02-01

    Full Text Available Histone deacetylases (HDACs have been extensively studied as drug targets in neurodegenerative diseases, but less is known about their role in healthy neurons. We tested zinc-dependent HDACs using RNAi in Drosophila melanogaster and found memory deficits with RPD3 and HDAC6. We demonstrate that HDAC6 is required in both the larval and adult stages for normal olfactory memory retention. Neuronal expression of HDAC6 rescued memory deficits, and we demonstrate that the N-terminal deacetylase (DAC domain is required for this ability. This suggests that deacetylation of synaptic targets associated with the first DAC domain, such as the active-zone scaffold Bruchpilot, is required for memory retention. Finally, electrophysiological experiments at the neuromuscular junction reveal that HDAC6 mutants exhibit a partial block of homeostatic plasticity, suggesting that HDAC6 may be required for the stabilization of synaptic strength. The learning deficit we observe in HDAC6 mutants could be a behavioral consequence of these synaptic defects.

  10. Proteomic analysis of pancreatic endocrine tumor cell lines treated with the histone deacetylase inhibitor trichostatin A.

    Science.gov (United States)

    Cecconi, Daniela; Donadelli, Massimo; Rinalducci, Sara; Zolla, Lello; Scupoli, Maria Teresa; Scarpa, Aldo; Palmieri, Marta; Righetti, Pier Giorgio

    2007-05-01

    Effects of the histone-deacetylases inhibitor trichostatin A (TSA) on the growth of three different human pancreatic endocrine carcinoma cell lines (CM, BON, and QGP-1) have been assessed via dosage-dependent growth inhibition curves. TSA determined strong inhibition of cell growth with similar IC(50) values for the different cell lines: 80.5 nM (CM), 61.6 nM (BON), and 86 nM (QGP-1), by arresting the cell cycle in G2/M phase and inducing apoptosis. 2DE and nano-RP-HPLC-ESI-MS/MS analysis revealed 34, 33, and 38 unique proteins differentially expressed after TSA treatment in the CM, BON, and QGP-1 cell lines, respectively. The most important groups of modulated proteins belong to cell proliferation, cell cycle, and apoptosis classes (such as peroxiredoxins 1 and 2, the diablo protein, and HSP27). Other proteins pertain to processes such as regulation of gene expression (nucleophosmin, oncoprotein dek), signal transduction (calcium-calmodulin), chromatin, and cytoskeleton organization (calgizzarin, dynein, and lamin), RNA splicing (nucleolin, HNRPC), and protein folding (HSP70). The present data are in agreement with previous proteomic analyses performed on pancreatic ductal carcinoma cell lines (Cecconi, D. et al.., Electrophoresis 2003; Cecconi, D. et al., J. Proteome Res. 2005) and place histone-deacetylases inhibitors among the potentially most powerful drugs for the treatment of pancreatic tumors.

  11. Prediction of pH-dependent aqueous solubility of Histone Deacetylase (HDAC) inhibitors

    DEFF Research Database (Denmark)

    Kouskoumvekaki, Irene; Hansen, Niclas Tue; Bjorkling, F.

    2008-01-01

    Recently we developed a model for prediction of pH-dependent aqueous solubility of drugs and drug like molecules. In the present work, the model was applied on a series of novel Histone Deacetylases (HDAC) inhibitors discovered at TopoTarget. The applicability of our model was evaluated on the se......Recently we developed a model for prediction of pH-dependent aqueous solubility of drugs and drug like molecules. In the present work, the model was applied on a series of novel Histone Deacetylases (HDAC) inhibitors discovered at TopoTarget. The applicability of our model was evaluated...... in the training data set of the ANN. The performance of the original and the two modified versions of the model were evaluated against the commercial software from Simulations-plus and pH-dependent solubility measurements for representative compounds of the series. The results of the evaluation indicate that one...... can develop models that are more accurate in predicting differences in the solubility of structurally very similar compounds than models that have been trained on structurally unbiased, diverse data sets. Such 'tailor-made' models have the potential to become trustworthy enough to replace time...

  12. The inhibitor of histone deacetylases sodium butyrate enhances the cytotoxicity of mitomycin C.

    Science.gov (United States)

    Gospodinov, Anastas; Popova, Stanislava; Vassileva, Ivelina; Anachkova, Boyka

    2012-10-01

    The use of histone deacetylase inhibitors has been proposed as a promising approach to increase the cell killing effect of DNA damage-inducing drugs in chemotherapy. However, the molecular mechanism of their action remains understudied. In the present article, we have assessed the effect of the histone deacetylase inhibitor sodium butyrate on the DNA damage response induced by the crosslinking agent mitomycin C. Sodium butyrate increased mitomycin C cytotoxicity, but did not impair the repair pathways required to remove mitomycin C-induced lesions as neither the rate of nucleotide excision repair nor the homologous recombination repair rate were diminished. Sodium butyrate treatment abrogated the S-phase cell-cycle checkpoint in mitomycin C-treated cells and induced the G(2)-M checkpoint. However, sodium butyrate treatment alone resulted in accumulation of reactive oxygen species, double-strand breaks in DNA, and apoptosis. These results imply that the accumulation of reactive oxygen species-mediated increase in DNA lesion burden may be the major mechanism by which sodium butyrate enhances the cytotoxicity of mitomycin C.

  13. Ky-2, a Histone Deacetylase Inhibitor, Enhances High-Salinity Stress Tolerance in Arabidopsis thaliana.

    Science.gov (United States)

    Sako, Kaori; Kim, Jong-Myong; Matsui, Akihiro; Nakamura, Kotaro; Tanaka, Maho; Kobayashi, Makoto; Saito, Kazuki; Nishino, Norikazu; Kusano, Miyako; Taji, Teruaki; Yoshida, Minoru; Seki, Motoaki

    2016-04-01

    Adaptation to environmental stress requires genome-wide changes in gene expression. Histone modifications are involved in gene regulation, but the role of histone modifications under environmental stress is not well understood. To reveal the relationship between histone modification and environmental stress, we assessed the effects of inhibitors of histone modification enzymes during salinity stress. Treatment with Ky-2, a histone deacetylase inhibitor, enhanced high-salinity stress tolerance in Arabidopsis. We confirmed that Ky-2 possessed inhibition activity towards histone deacetylases by immunoblot analysis. To investigate how Ky-2 improved salt stress tolerance, we performed transcriptome and metabolome analysis. These data showed that the expression of salt-responsive genes and salt stress-related metabolites were increased by Ky-2 treatment under salinity stress. A mutant deficient in AtSOS1(Arabidopis thaliana SALT OVERLY SENSITIVE 1), which encodes an Na(+)/H(+)antiporter and was among the up-regulated genes, lost the salinity stress tolerance conferred by Ky-2. We confirmed that acetylation of histone H4 at AtSOS1 was increased by Ky-2 treatment. Moreover, Ky-2 treatment decreased the intracellular Na(+)accumulation under salinity stress, suggesting that enhancement of SOS1-dependent Na(+)efflux contributes to increased high-salinity stress tolerance caused by Ky-2 treatment.

  14. O-GlcNAcylation of histone deacetylases 1 in hepatocellular carcinoma promotes cancer progression.

    Science.gov (United States)

    Zhu, Guizhou; Tao, Tao; Zhang, Dongmei; Liu, Xiaojuan; Qiu, Huiyuan; Han, LiJian; Xu, Zhiwei; Xiao, Ying; Cheng, Chun; Shen, Aiguo

    2016-08-01

    Hepatocellular carcinoma (HCC) is a malignant tumor originating in the liver. Previous studies have indicated that O-GlcNAc transferase (OGT) and histone deacetylase-1 (HDAC1) play important roles in the pathogenesis of HCC. In the present study, we investigated the physical link between OGT and HDAC1. The O-GlcNAcylation of HDAC1 is overexpressed in HCC. We found that HDAC1 has two major sites of O-GlcNAcylation in its histone deacetylase domain. HDAC1 O-GlcNAcylation increases the activated phosphorylation of HDAC1, which enhances its enzyme activity. HDAC1 O-GlcNAc mutants promote the p21 transcription regulation through affecting the acetylation levels of histones from chromosome, and then influence the proliferation of HCC cells. We also found that mutants of O-GlcNAcylation site of HDAC1 affect invasion and migration of HepG2 cells. E-cadherin level is highly up-regulated in HDAC1 O-GlcNAc mutant-treated liver cancer cells, which inhibit the occurrence and development of HCC. Our findings suggest that OGT promotes the O-GlcNAc modification of HDAC1in the development of HCC. Therefore, inhibiting O-GlcNAcylation of HDAC1 may repress the progression of HCC.

  15. Histone deacetylase 1 and 3 regulate the mesodermal lineage commitment of mouse embryonic stem cells.

    Directory of Open Access Journals (Sweden)

    Weiying Lv

    Full Text Available The important role of histone acetylation alteration has become increasingly recognized in mesodermal lineage differentiation and development. However, the contribution of individual histone deacetylases (HDACs to mesoderm specification remains poorly understood. In this report, we found that trichostatin A (TSA, an inhibitor of histone deacetylase (HDACi, could induce early differentiation of embryonic stem cells (ESCs and promote mesodermal lineage differentiation. Further analysis showed that the expression levels of HDAC1 and 3 are decreased gradually during ESCs differentiation. Ectopic expression of HDAC1 or 3 significantly inhibited differentiation into the mesodermal lineage. By contrast, loss of either HDAC1 or 3 enhanced the mesodermal differentiation of ESCs. Additionally, we demonstrated that the activity of HDAC1 and 3 is indeed required for the regulation of mesoderm gene expression. Furthermore, HDAC1 and 3 were found to interact physically with the T-box transcription factor T/Bry, which is critical for mesodermal lineage commitment. These findings indicate a key mechanism for the specific role of HDAC1 and 3 in mammalian mesoderm specification.

  16. Complex structure of a bacterial class 2 histone deacetylase homologue with a trifluoromethylketone inhibitor

    Energy Technology Data Exchange (ETDEWEB)

    Nielsen, Tine Kragh [Abteilung für Molekulare Strukturbiologie, Institut für Mikrobiologie und Genetik and GZMB, Justus-von-Liebig Weg 11, 37077 Göttingen (Germany); Hildmann, Christian; Riester, Daniel; Wegener, Dennis; Schwienhorst, Andreas [Abteilung für Molekulare Genetik und Präparative Molekularbiologie, Institut für Mikrobiologie und Genetik, Grisebachstrasse 8, 37077 Göttingen (Germany); Ficner, Ralf, E-mail: rficner@gwdg.de [Abteilung für Molekulare Strukturbiologie, Institut für Mikrobiologie und Genetik and GZMB, Justus-von-Liebig Weg 11, 37077 Göttingen (Germany)

    2007-04-01

    The crystal structure of HDAH FB188 in complex with a trifluoromethylketone at 2.2 Å resolution is reported and compared to a previously determined inhibitor complex. Histone deacetylases (HDACs) have emerged as attractive targets in anticancer drug development. To date, a number of HDAC inhibitors have been developed and most of them are hydroxamic acid derivatives, typified by suberoylanilide hydroxamic acid (SAHA). Not surprisingly, structural information that can greatly enhance the design of novel HDAC inhibitors is so far only available for hydroxamic acids in complex with HDAC or HDAC-like enzymes. Here, the first structure of an enzyme complex with a nonhydroxamate HDAC inhibitor is presented. The structure of the trifluoromethyl ketone inhibitor 9,9,9-trifluoro-8-oxo-N-phenylnonanamide in complex with bacterial FB188 HDAH (histone deacetylase-like amidohydrolase from Bordetella/Alcaligenes strain FB188) has been determined. HDAH reveals high sequential and functional homology to human class 2 HDACs and a high structural homology to human class 1 HDACs. Comparison with the structure of HDAH in complex with SAHA reveals that the two inhibitors superimpose well. However, significant differences in binding to the active site of HDAH were observed. In the presented structure the O atom of the trifluoromethyl ketone moiety is within binding distance of the Zn atom of the enzyme and the F atoms participate in interactions with the enzyme, thereby involving more amino acids in enzyme–inhibitor binding.

  17. Role of histone deacetylases in pancreas: Implications for pathogenesis and therapy

    Institute of Scientific and Technical Information of China (English)

    Eckhard; Klieser; Stefan; Swierczynski; Christian; Mayr; Johanna; Schmidt; Daniel; Neureiter; Tobias; Kiesslich; Romana; Illig

    2015-01-01

    In the last years, our knowledge of the pathogenesis in acute and chronic pancreatitis(AP/CP) as well as in pancreatic cancerogenesis has significantly diversified. Nevertheless, the medicinal therapeutic options are still limited and therapeutic success and patient outcome are poor. Epigenetic deregulation of gene expression is known to contribute to development and progression of AP and CP as well as of pancreatic cancer. Therefore, the selective inhibition of aberrantly active epigenetic regulators can be an effective option for future thera-pies. Histone deacetylases(HDACs) are enzymes that remove an acetyl group from histone tails, thereby causing chromatin compaction and repression of transcri-ption. In this review we present an overview of the currently available literature addressing the role of HDACs in the pancreas and in pancreatic diseases. In pancreatic cancerogenesis, HDACs play a role in the important process of epithelial-mesenchymal-transition, ubiquitin-proteasome pathway and, hypoxia-inducible-factor-1-angiogenesis. Finally, we focus on HDACs as potential therapeutic targets by summarizing currently available histone deacetylase inhibitors.

  18. Biomedical exploitation of chitin and chitosan via mechano-chemical disassembly, electrospinning, dissolution in imidazolium ionic liquids, and supercritical drying.

    Science.gov (United States)

    Muzzarelli, Riccardo A A

    2011-01-01

    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 CO(2) 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.

  19. 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.

  20. Cytolocalization of the class V chitin synthase in the yeast, hyphal and sclerotic morphotypes of Wangiella (Exophiala) dermatitidis.

    Science.gov (United States)

    Abramczyk, Dariusz; Park, Changwon; Szaniszlo, Paul J

    2009-01-01

    Wangiella (Exophiala) dermatitidis is a polymorphic fungus that produces polarized yeast and hyphae, as well as a number of non-polarized sclerotic morphotypes. The phenotypic malleability of this agent of human phaeohyphomycosis allows detailed study of its biology, virulence and the regulatory mechanisms responsible for the transitions among the morphotypes. Our prior studies have demonstrated the existence of seven chitin synthase structural genes in W. dermatitidis, each of which encodes an isoenzyme of a different class. Among them, the class V chitin synthase (WdChs5p) is most unique in terms of protein structure, because it has an N-terminal myosin motor-like domain with a P-loop (MMD) fused to its C-terminal chitin synthase catalytic domain (CSCD). However, the exact role played by WdChs5p in the different morphotypes remains undefined beyond the knowledge that it is the only single chitin synthase required for sustained cell growth at 37 degrees C and consequently virulence. This report describes the expression in Escherichia coli of a 12kDa polypeptide (WdMyo12p) of WdChs5p, which was used to raise in rabbits a polyclonal antibody that recognized exclusively its MMD region. Results from the use of the antibody in immunocytolocalization studies supported our previous findings that WdChs5p is critically important at infection temperatures for maintaining the cell wall integrity of developing yeast buds, elongating tips of hyphae, and random sites of expansion in sclerotic forms. The results also suggested that WdChs5p localizes to the regions of cell wall growth in an actin-dependent fashion.

  1. 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...

  2. Oral Administration of Surface-Deacetylated Chitin Nanofibers and Chitosan Inhibit 5-Fluorouracil-Induced Intestinal Mucositis in Mice

    Science.gov (United States)

    Koizumi, Ryo; Azuma, Kazuo; Izawa, Hironori; Morimoto, Minoru; Ochi, Kosuke; Tsuka, Takeshi; Imagawa, Tomohiro; Osaki, Tomohiro; Ito, Norihiko; Okamoto, Yoshiharu; Saimoto, Hiroyuki; Ifuku, Shinsuke

    2017-01-01

    This study investigated the prophylactic effects of orally administered surface-deacetylated chitin nanofibers (SDACNFs) and chitosan against 5-fluorouracil (5-FU)-induced intestinal mucositis, which is a common side effect of 5-FU chemotherapy. SDACNFs and chitosan abolished histological abnormalities associated with intestinal mucositis and suppressed hypoproliferation and apoptosis of intestinal crypt cells. These results indicate that SDACNF and chitosan are useful agents for preventing mucositis induced by anti-cancer drugs. PMID:28134832

  3. First evidence of chitin in calcified coralline algae: new insights into the calcification process of Clathromorphum compactum

    Science.gov (United States)

    Rahman, M. Azizur; Halfar, Jochen

    2014-08-01

    Interest in calcifying coralline algae has been increasing over the past years due to the discovery of extensive coralline algal dominated ecosystems in Arctic and Subarctic latitudes, their projected sensitivity to ocean acidification and their utility as palaeoenvironmental proxies. Thus, it is crucial to obtain a detailed understanding of their calcification process. We here extracted calcified skeletal organic matrix components including soluble and insoluble fractions from the widely-distributed Subarctic and Arctic coralline alga Clathromorphum compactum. The lyophilized skeletal organic matrix fractions showed comparatively high concentrations of soluble and insoluble organic matrices comprising 0.9% and 4.5% of skeletal weight, respectively. This is significantly higher than in other skeletal marine calcifiers. Attenuated Total Reflection-Fourier Transform Infrared Spectroscopy (ATR-FTIR) and X-Ray Diffraction (XRD) results indicate that chitin is present in the skeletal organic matrices of C. compactum. This polymer exhibits similar hierarchical structural organizations with collagen present in the matrix and serves as a template for nucleation and controls the location and orientation of mineral phases. Chitin contributes to significantly increasing skeletal strength, making C. compactum highly adapted for living in a shallow high-latitude benthic environment. Furthermore, chitin containing polysaccharides can increase resistance of calcifiers to negative effects of ocean acidification.

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

    Science.gov (United States)

    Larsen, Tanja; Petersen, Bent O; Storgaard, Birgit G; Duus, Jens Ø; Palcic, Monica M; Leisner, Jørgen J

    2011-04-01

    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-terminal truncated form of chiA lacking a putative chitin-binding domain was amplified by PCR, cloned and expressed in Escherichia coli BL21 (DE3) with an N-terminal (His)(6) tag. The purified enzyme hydrolyzes 4-nitrophenyl N,N'-diacetyl-β-D-chitobioside, 4-nitrophenyl β-D-N,N',N″-triacetylchitotriose and carboxymethyl chitin Remazol Brilliant Violet but does not act on 4-nitrophenyl N-acetyl-β-D-glucosaminide, peptidoglycan or 4-nitrophenyl β-D-cellobioside. Enzyme activity was also characterized by directly monitoring product formation using (1)H-nuclear magnetic resonance which showed that chitin is a substrate with the release of N,N'-diacetylchitobiose. Hydrolysis occurs with the retention of configuration and the enzyme acts on only the β-anomers of chitooligosaccharide substrates. The enzyme also released N-acetyllactosamine disaccharide from Galβ1 → 4GlcNAcβ-O-(CH(2))(8)CONH(CH(2))(2)NHCO-tetramethylrhodamine, a model substrate for LacNAc terminating glycoproteins and glycolipids.

  5. 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.

  6. 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.

  7. Synthesis of chitin nanofibers, MWCNTs and MnO2 nanoflakes 3D porous network flexible gel-film for high supercapacitive performance electrodes

    Science.gov (United States)

    Liu, Shengnan; Li, Dagang

    2017-03-01

    As the porous structure and conductivity result in improvement of electrochemical properties, the chitin nanofibers (ChNFs), multi-walled carbon nanotubes (MWCNTs) and MnO2 (manganese dioxide) nanoflakes 3D porous network core-shell structure gel-film was fabricated for flexible free-standing supercapacitor electrodes. The electrodes were characterized by various techniques and the results demonstrate that the as-synthesized ChNFs/MWCNTs/MnO2 gel-film electrodes exhibits excellent supercapacitive behaviours. The ChNFs/MWCNTs/MnO2 gel-film electrode shows a high capacitance of 295.2 mF/cm2 at 0.1 mA/cm2 in 1 M Na2SO4 aqueous electrolyte because of its 3D porous structure. Furthermore, the electrodes also showed surprising cycling stability for 5000 cycles with retention rate up to 157.14% at 1 mA/cm2. The data presents great promise in the application of high-performance flexible supercapacitors with the low cost, light-weight and excellent cycling ability.

  8. Fibrous Polymeric Composites Based on Alginate Fibres and Fibres Made of Poly-ε-caprolactone and Dibutyryl Chitin for Use in Regenerative Medicine

    Directory of Open Access Journals (Sweden)

    Elżbieta Menaszek

    2013-03-01

    Full Text Available This work concerns the production of fibrous composite materials based on biodegradable polymers such as alginate, dibutyryl chitin (DBC and poly-ε-caprolactone (PCL. For the production of fibres from these polymers, various spinning methods were used in order to obtain composite materials of different composition and structure. In the case of alginate fibres containing the nanoadditive tricalcium phosphate (TCP, the traditional method of forming fibres wet from solution was used. However in the case of the other two polymers the electrospinning method was used. Two model systems were tested for biocompatibility. The physicochemical and basic biological tests carried out show that the submicron fibres produced using PCL and DBC have good biocompatibility. The proposed hybrid systems composed of micrometric fibres (zinc and calcium alginates containing TCP and submicron fibres (DBC and PCL meet the requirements of regenerative medicine. The biomimetic fibre system, the presence of TCP nanoadditive, and the use of polymers with different resorption times provide a framework with specific properties on which bone cells are able to settle and proliferate.

  9. Sodium valproate-induced congenital cardiac abnormalities in mice are associated with the inhibition of histone deacetylase

    Directory of Open Access Journals (Sweden)

    Rollo Johnathon C

    2010-03-01

    Full Text Available Abstract Background Valproic acid, a widely used anticonvulsant drug, is a potent teratogen resulting in various congenital abnormalities. However, the mechanisms underlying valproic acid induced teratogenesis are nor clear. Recent studies indicate that histone deacetylase is a direct target of valproic acid. Methods In the present study, we have used histological analysis and RT-PCR assays to examine the cardiac abnormalities in mice treated with sodium valproate (NaVP and determined the effects of NaVP on histone deacetylase activity and the expression of heart development-related genes in mouse myocardial cells. Results The experimental data show that NaVP can induce cardiac abnormalities in fetal mice in a dose-dependent manner. NaVP causes a dose-dependent inhibition of hitone deacetylase (HDAC activity in mouse myocardial cells. However, the expression levels of HDAC (both HDAC1 and HDAC2 are not significantly changed in fetal mouse hearts after administration of NaVP in pregnant mice. The transcriptional levels of other heart development-related genes, such as CHF1, Tbx5 and MEF2, are significantly increased in fetal mouse hearts treated with NaVP. Conclusions The study indicates that administration of NaVP in pregnant mice can result in various cardiac abnormalities in fetal hearts, which is associated with an inhibition of histone deacetylase without altering the transcription of this enzyme.

  10. NAD(+)- dependent deacetylase SIRT3 regulates mitochondrial protein synthesis by deacetylation of the ribosomal protein MRPL10

    Science.gov (United States)

    A member of the sirtuin family of NAD (+)-dependent deacetylases, SIRT3, is located in mammalian mitochondria and is important for regulation of mitochondrial metabolism, cell survival, and longevity. In this study, MRPL10 (mitochondrial ribosomal protein L10) was identified as the major acetylated ...

  11. The Histone Deacetylase SIRT1 Controls Male Fertility in Mice Through Regulation of Hypothalamic-Pituitary Gonadotropin Signaling

    NARCIS (Netherlands)

    Teerds, K.J.; Kolthur-Seerharam, U.; Rooij, de D.G.

    2009-01-01

    Sirtuins (SIRTs) are class-III NAD-dependent histone deacetylases (HDACs) that regulate various physiological processes. Inactivation of SIRT1 in the mouse leads to male sterility, but the molecular mechanisms responsible for this phenotype have not been determined. Here we show that fetal testis de

  12. Combining the pan-aurora kinase inhibitor AMG 900 with histone deacetylase inhibitors enhances antitumor activity in prostate cancer

    NARCIS (Netherlands)

    Paller, C.J.; Wissing, M.D.; Mendonca, J.; Sharma, A.; Kim, E.; Kim, H.S.; Kortenhorst, M.S.Q.; Gerber, S.; Rosen, M.; Shaikh, F.; Zahurak, M.L.; Rudek, M.A.; Hammers, H.; Rudin, C.M.; Carducci, M.A.; Kachhap, S.K.

    2014-01-01

    Histone deacetylase inhibitors (HDACIs) are being tested in clinical trials for the treatment of solid tumors. While most studies have focused on the reexpression of silenced tumor suppressor genes, a number of genes/pathways are downregulated by HDACIs. This provides opportunities for combination t

  13. A phase I clinical trial of the histone deacetylase inhibitor belinostat in patients with advanced hematological neoplasia

    DEFF Research Database (Denmark)

    Gimsing, Peter; Hansen, Mads; Knudsen, Lene M;

    2008-01-01

    PURPOSE: To determine the safety, dose-limiting toxicity and maximum tolerated dose (MTD) of the novel hydroxamate histone deacetylase inhibitor belinostat (PXD101) in patients with advanced hematological neoplasms. PATIENTS AND METHODS: Sequential dose-escalating cohorts of three to six patients...

  14. Valproic Acid as a Potential Inhibitor of Plasmodium falciparum Histone Deacetylase 1 (PfHDAC1: An in Silico Approach

    Directory of Open Access Journals (Sweden)

    Mohamed A. Abdallah Elbadawi

    2015-02-01

    Full Text Available A new Plasmodium falciparum histone deacetylase1 (PfHDAC1 homology model was built based on the highest sequence identity available template human histone deacetylase 2 structure. The generated model was carefully evaluated for stereochemical accuracy, folding correctness and overall structure quality. All evaluations were acceptable and consistent. Docking a group of hydroxamic acid histone deacetylase inhibitors and valproic acid has shown binding poses that agree well with inhibitor-bound histone deacetylase-solved structural interactions. Docking affinity dG scores were in agreement with available experimental binding affinities. Further, enzyme-ligand complex stability and reliability were investigated by running 5-nanosecond molecular dynamics simulations. Thorough analysis of the simulation trajectories has shown that enzyme-ligand complexes were stable during the simulation period. Interestingly, the calculated theoretical binding energies of the docked hydroxamic acid inhibitors have shown that the model can discriminate between strong and weaker inhibitors and agrees well with the experimental affinities reported in the literature. The model and the docking methodology can be used in screening virtual libraries for PfHDAC1 inhibitors, since the docking scores have ranked ligands in accordance with experimental binding affinities. Valproic acid calculated theoretical binding energy suggests that it may inhibit PfHDAC1.

  15. Post-Training Intrahippocampal Inhibition of Class I Histone Deacetylases Enhances Long-Term Object-Location Memory

    Science.gov (United States)

    Hawk, Joshua D.; Florian, Cedrick; Abel, Ted

    2011-01-01

    Long-term memory formation involves covalent modification of the histone proteins that package DNA. Reducing histone acetylation by mutating histone acetyltransferases impairs long-term memory, and enhancing histone acetylation by inhibiting histone deacetylases (HDACs) improves long-term memory. Previous studies using HDAC inhibitors to enhance…

  16. 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.

  17. Murine hematopoietic stem cell dormancy controlled by induction of a novel short form of PSF1 by histone deacetylase inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Han, Yinglu; Gong, Zhi-Yuan [Department of Signal Transduction, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamada-oka, Suita, Osaka 565-0871 (Japan); Takakura, Nobuyuki, E-mail: ntakaku@biken.osaka-u.ac.jp [Department of Signal Transduction, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamada-oka, Suita, Osaka 565-0871 (Japan); Japan Science Technology Agency, CREST, K' s Gobancho, 7, Gobancho, Chiyoda-ku, Tokyo 102-0076 (Japan)

    2015-06-10

    Hematopoietic stem cells (HSCs) can survive long-term in a state of dormancy. Little is known about how histone deacetylase inhibitors (HDACi) affect HSC kinetics. Here, we use trichostatin A (TSA), a histone deacetylase inhibitor, to enforce histone acetylation and show that this suppresses cell cycle entry by dormant HSCs. Previously, we found that haploinsufficiency of PSF1, a DNA replication factor, led to attenuation of the bone marrow (BM) HSC pool size and lack of acute proliferation after 5-FU ablation. Because PSF1 protein is present in CD34{sup +} transiently amplifying HSCs but not in CD34{sup −} long-term reconstituting-HSCs which are resting in a dormant state, we analyzed the relationship between dormancy and PSF1 expression, and how a histone deacetylase inhibitor affects this. We found that CD34{sup +} HSCs produce long functional PSF1 (PSF1a) but CD34{sup −} HSCs produce a shorter possibly non-functional PSF1 (PSF1b, c, dominantly PSF1c). Using PSF1a-overexpressing NIH-3T3 cells in which the endogenous PSF1 promoter is suppressed, we found that TSA treatment promotes production of the shorter form of PSF1 possibly by inducing recruitment of E2F family factors upstream of the PSF1 transcription start site. Our data document one mechanism by which histone deacetylase inhibitors affect the dormancy of HSCs by regulating the DNA replication factor PSF1. - Highlights: • Hematopoetic stem cell dormancy is controlled by histone deacetylation inhibitors. • Dormancy of HSCs is associated with a shorter form of non-functional PSF1. • Histone deacetylase inhibitors suppress PSF1 promoter activity.

  18. Effects of Surface-Deacetylated Chitin Nanofibers in an Experimental Model of Hypercholesterolemia

    Directory of Open Access Journals (Sweden)

    Kazuo Azuma

    2015-07-01

    Full Text Available This study evaluated the effects of oral administration of surface-deacetylated chitin nanofibers (SDACNFs on hypercholesterolemia using an experimental model. All rats were fed a high cholesterol diet with 1% w/w cholesterol and 0.5% w/w cholic acid for 28 days. Rats were divided equally into four groups: the control group was administered 0.05% acetic acid dissolved in tap water, and the SDACNF, chitosan (CS, and cellulose nanofiber (CLNF groups were administered 0.1% CNF, CS, or CLNF dissolved in the tap water, respectively, during the experimental period. Changes in body weight, intake of food and water, and organ weight were measured. Serum blood chemistry and histopathological examination of the liver were performed. Administration of SDACNF did not affect body weight change, food and water intake, or organ weights. Administration of SDACNF and CS decreased the diet-induced increase in serum total cholesterol, chylomicron, very-low-density lipoprotein, and phospholipid levels on day 14. Moreover, oral administration of SDACNFs suppressed the increase of alanine transaminase levels on day 29 and suppressed vacuolar degeneration and accumulation of lipid droplets in liver tissue. These data indicate that SDACNF has potential as a functional food for patients with hypercholesterolemia.

  19. 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.

  20. 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.

  1. Evolution of the chitin synthase gene family correlates with fungal morphogenesis and adaption to ecological niches

    Science.gov (United States)

    Liu, Ran; Xu, Chuan; Zhang, Qiangqiang; Wang, Shiyi; Fang, Weiguo

    2017-01-01

    The fungal kingdom potentially has the most complex chitin synthase (CHS) gene family, but evolution of the fungal CHS gene family and its diversification to fulfill multiple functions remain to be elucidated. Here, we identified the full complement of CHSs from 231 fungal species. Using the largest dataset to date, we characterized the evolution of the fungal CHS gene family using phylogenetic and domain structure analysis. Gene duplication, domain recombination and accretion are major mechanisms underlying the diversification of the fungal CHS gene family, producing at least 7 CHS classes. Contraction of the CHS gene family is morphology-specific, with significant loss in unicellular fungi, whereas family expansion is lineage-specific with obvious expansion in early-diverging fungi. ClassV and ClassVII CHSs with the same domain structure were produced by the recruitment of domains PF00063 and PF08766 and subsequent duplications. Comparative analysis of their functions in multiple fungal species shows that the emergence of ClassV and ClassVII CHSs is important for the morphogenesis of filamentous fungi, development of pathogenicity in pathogenic fungi, and heat stress tolerance in Pezizomycotina fungi. This work reveals the evolution of the fungal CHS gene family, and its correlation with fungal morphogenesis and adaptation to ecological niches. PMID:28300148

  2. 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

  3. Halo(natronoarchaea isolated from hypersaline lakes utilize cellulose and chitin as growth substrates

    Directory of Open Access Journals (Sweden)

    Dimitry Y Sorokin

    2015-09-01

    Full Text Available 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 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 (GHs 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(natronoarchaeal 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 population of haloarchaeal cellulo/chitinotrophs in hypersaline habitats indicating that euryarchaea participate in aerobic mineralization of recalcitrant organic polymers in salt-saturated environments.

  4. Cytotoxicity of Silver Nanoparticle and Chitin-Nanofiber Sheet Composites Caused by Oxidative Stress

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    Jun Kinoda

    2016-10-01

    Full Text Available Size-controlled spherical silver nanoparticles (<10 nm and chitin-nanofiber sheet composites (Ag NPs/CNFS have previously been reported to have strong antimicrobial activity in vitro. Although Ag NPs/CNFS have strong antimicrobial activity, their cytotoxicity has not been investigated. This study was performed to evaluate the effects of Ag NPs/CNFS on cytotoxicity for fibroblasts in vitro and healing delay of wound repair in vivo, focused on oxidative stress. Cytotoxic activities of Ag NPs/CNFS were investigated using a fibroblast cell proliferation assay, nitric oxide/nitrogen dioxide (NO/NO2 measurement of the cell lysates in vitro, inhibitory effects of Ag NPs/CNFS on healing-impaired wound repair using diabetic mice in vivo, 8-hydroxy-2′-deoxyguanosine (8-OHdG immunohistochemical staining of the skin sections, and generation of carbonyl protein in the wound was performed to evaluate cytotoxicity with oxidative stress. Ag NPs/CNFS exhibited cytotoxicity for fibroblasts and a significant increase of total NO/NO2 levels in the cell lysates in vitro and increased levels of 8-OHdG and carbonyl proteins in vivo. Although wound repair in the continuously Ag NPs/CNFS-treated group was delayed, it could be mitigated by washing the covered wound with saline. Thus, Ag NPs/CNFS may become accepted as an anti-infectious wound dressing.

  5. Chitin nanowhisker (ChNW)-functionalized electrospun PVDF membrane for enhanced removal of Indigo carmine.

    Science.gov (United States)

    Gopi, Sreerag; Balakrishnan, Preetha; Pius, Anitha; Thomas, Sabu

    2017-06-01

    In this study, an active functional adsorbent membrane developed by combining both hydrophilic bio polymer filler such as chitin nanowhiskers (ChNW) which contains two functional groups and a hydrophobic polymer matrix such as polyvinylidene fluoride (PVDF) using electrospinning technique. Here ChNW were successfully extracted by excluding proteins and mineral and well characterized using FTIR, XRD, SEM and TEM. The optimized combination of PVDF/ChNW (15%:1%) membrane was fabricated and well characterized using SEM, water contact angle and FTIR spectroscopy. There was a remarkable difference in contact angle observed for PVDF/ChNW (22.72°) compared to neat PVDF (93.1°) membrane. Ultimately the membrane used for indigo carmine (IC) adsorption and an enhanced removal efficiency (88.9%) and adsorption capacity (72.6mgg(-1)) were observed compared to neat PVDF. In the future, the overall idea can make leads to various applications such as proteins, virus and hormones adsorption from the contaminated sources.

  6. Improved production of chitin from shrimp waste by fermentation with epiphytic lactic acid bacteria.

    Science.gov (United States)

    Duan, Shan; Li, Lei; Zhuang, Zejuan; Wu, Wenya; Hong, Shuying; Zhou, Jiehua

    2012-08-01

    The epiphytic Lactobacillus acidophilus SW01 isolated from shrimp waste (SW) was used in SW fermentation. During the fermentation the lag phase of SW01 was hardly observed. The pH of the fermentation broth decreased to 3.86 within 12h and reached the lowest point at 3.73 after 48 h. This indicates a quick and deep acidification process by SW01. Besides, SW01 was observed to have high protease activity. As a result, the minerals and protein in SW were quickly removed with their contents decreasing to 0.73% and 7.8% respectively after 48 h fermentation. In the pilot scale fermentation, the pH was 3.99 and 3.86 respectively after 12 and 24 h fermentation. The mineral and protein contents were 0.98% and 8.44% respectively after 48 h fermentation. The residue of the fermented SW contains less than 1% minerals and can be easily transformed into chitin by a mere bleaching treatment.

  7. 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.

  8. 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.

  9. Developing a Novel Indolocarbazole as Histone Deacetylases Inhibitor against Leukemia Cell Lines

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    Wenjing Wang

    2015-01-01

    Full Text Available A novel indolocarbazole (named as ZW2-1 possessing HDAC inhibition activity was synthesized and evaluated against human leukemia cell lines HL-60 and NB4. ZW2-1 performed anti-population growth effect which was in a concentration-dependent manner (2–12 μM by inducing both apoptosis and autophagy in cells. The compound also caused differentiation of HL-60 and NB4 cells as shown by increasing expression of CD11b, CD14, and CD38 at moderate concentration (4 μM. At relatively high concentration (8 μM, ZW2-1 significantly decreased intracellular histone deacetylase 1 level which was also observed. All the results indicated that ZW2-1 could be a novel antileukemia lead capable of simultaneously inducing apoptosis, autophagy, and differentiation.

  10. A novel histone deacetylase inhibitor augments tamoxifen-mediated attenuation of breast carcinoma growth.

    Science.gov (United States)

    Restall, Christina; Doherty, Judy; Liu, Hong Bin; Genovese, Rosemary; Paiman, Lisa; Byron, Keith A; Anderson, Robin L; Dear, Anthony E

    2009-07-15

    Earlier we generated novel derivatives of the hydroxamate-based histone deacetylase inhibitor (HDACi), Oxamflatin (Ox), which demonstrate considerable HDACi activity. Here the effects of one such derivative, Metacept-1 (MCT-1), alone or in combination with tamoxifen on mammary tumour growth have been assessed in a syngeneic orthotopic model. MCT-1 alone resulted in a trend towards inhibition of growth of 4T1.2 mammary tumours. Since the combination of MCT-1 and tamoxifen up-regulates estrogen receptor expression in 4T1.2 cells in vitro, we tested this combination and found a significant reduction in primary tumour growth over tamoxifen treatment alone. Taken together, these observations suggest that the novel HDACi MCT-1 may warrant further exploration in the treatment of estrogen receptor positive breast carcinoma, particularly when used in combination with conventional agents such as tamoxifen.

  11. Proteomic investigations of lysine acetylation identify diverse substrates of mitochondrial deacetylase sirt3

    DEFF Research Database (Denmark)

    Sol, E-ri Maria; Wagner, Sebastian A; Weinert, Brian T;

    2012-01-01

    of KDACs and pinpointing the regulated acetylation sites on target proteins may provide important information about the molecular basis of their functions. Here we apply quantitative proteomics to identify endogenous substrates of the mitochondrial deacetylase Sirtuin 3 (Sirt3) by comparing site......-specific acetylation in wild-type murine embryonic fibroblasts to Sirt3 knockout cells. We confirm Sirt3-regulated acetylation of several mitochondrial proteins in human cells by comparing acetylation in U2OS cells overexpressing Sirt3 to U2OS cells in which Sirt3 expression was reduced by shRNA. Our data demonstrate...... that ablation of Sirt3 significantly increases acetylation at dozens of sites on mitochondrial proteins. Substrates of Sirt3 are implicated in various metabolic pathways, including fatty acid metabolism and the tricarboxylic acid cycle. These results imply broader regulatory roles of Sirt3 in the mitochondria...

  12. The interplay between microRNAs and histone deacetylases in neurological diseases.

    Science.gov (United States)

    Bourassa, Megan W; Ratan, Rajiv R

    2014-11-01

    Neurological conditions, such as Alzheimer's disease and stroke, represent a prevalent group of devastating illnesses with few treatments. Each of these diseases or conditions is in part characterized by the dysregulation of many genes, including those that code for microRNAs (miRNAs) and histone deacetylases (HDACs). Recently, a complex relationship has been uncovered linking miRNAs and HDACs and their ability to regulate one another. This provides a new avenue for potential therapeutics as the ability to reinstate a careful balance between miRNA and HDACs has lead to improved outcomes in a number of in vitro and in vivo models of neurological conditions. In this review, we will discuss recent findings on the interplay between miRNAs and HDACs and its implications for pathogenesis and treatment of neurological conditions, including amyotrophic lateral sclerosis, Alzheimer's disease, Huntington's disease and stroke.

  13. 3-Hydroxypyridin-2-thione as novel zinc binding group for selective histone deacetylase inhibition.

    Science.gov (United States)

    Patil, Vishal; Sodji, Quaovi H; Kornacki, James R; Mrksich, Milan; Oyelere, Adegboyega K

    2013-05-09

    Small molecules bearing hydroxamic acid as the zinc binding group (ZBG) have been the most effective histone deacetylase inhibitors (HDACi) to date. However, concerns about the pharmacokinetic liabilities of the hydroxamic acid moiety have stimulated research efforts aimed at finding alternative nonhydroxamate ZBGs. We have identified 3-hydroxypyridin-2-thione (3-HPT) as a novel ZBG that is compatible with HDAC inhibition. 3-HPT inhibits HDAC 6 and HDAC 8 with an IC50 of 681 and 3675 nM, respectively. Remarkably, 3-HPT gives no inhibition of HDAC 1. Subsequent optimization led to several novel 3HPT-based HDACi that are selective for HDAC 6 and HDAC 8. Furthermore, a subset of these inhibitors induces apoptosis in various cancer cell lines.

  14. Myelodysplastic Syndrome and Histone Deacetylase Inhibitors: “To Be or Not to Be Acetylated”?

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    Sebastian Stintzing

    2011-01-01

    Full Text Available Myelodysplastic syndrome (MDS represents a heterogeneous group of diseases with clonal proliferation, bone marrow failure and increasing risk of transformation into an acute myeloid leukaemia. Structured guidelines are developed for selective therapy based on prognostic subgroups, age, and performance status. Although many driving forces of disease phenotype and biology are described, the complete and possibly interacting pathogenetic pathways still remain unclear. Epigenetic investigations of cancer and haematologic diseases like MDS give new insights into the pathogenesis of this complex disease. Modifications of DNA or histones via methylation or acetylation lead to gene silencing and altered physiology relevant for MDS. First clinical trials give evidence that patients with MDS could benefit from epigenetic treatment with, for example, DNA methyl transferase inhibitors (DNMTi or histone deacetylase inhibitors (HDACi. Nevertheless, many issues of HDACi remain incompletely understood and pose clinical and translational challenges. In this paper, major aspects of MDS, MDS-associated epigenetics and the potential use of HDACi are discussed.

  15. Histone deacetylase inhibitor treatment attenuates coagulation imbalance in a lethal murine model of sepsis

    DEFF Research Database (Denmark)

    Zhao, Ting; Li, Yongqing; Liu, Baoling;

    2014-01-01

    BACKGROUND: Sepsis has a profound impact on the inflammatory and hemostatic systems. In addition to systemic inflammation, it can produce disseminated intravascular coagulation, microvascular thrombosis, consumptive coagulopathy, and multiple organ failure. We have shown that treatment with suber......BACKGROUND: Sepsis has a profound impact on the inflammatory and hemostatic systems. In addition to systemic inflammation, it can produce disseminated intravascular coagulation, microvascular thrombosis, consumptive coagulopathy, and multiple organ failure. We have shown that treatment...... with suberoylanilide hydroxamic acid (SAHA), a histone deacetylase inhibitor (HDACI), improves survival in a lethal model of cecal ligation and puncture (CLP) in mice, but its effect on coagulation remains unknown. The goal of this study was to quantify the impact of SAHA treatment on coagulopathy in sepsis. METHODS...... and attenuates sepsis-associated coagulopathy by improving fibrin cross-linkage, rate of clot formation, platelet function, and clot strength. HDACI may represent a novel therapeutic strategy for correcting sepsis-associated coagulopathy....

  16. The role of butyrate, a histone deacetylase inhibitor in diabetes mellitus: experimental evidence for therapeutic intervention.

    Science.gov (United States)

    Khan, Sabbir; Jena, Gopabandhu

    2015-01-01

    The contribution of epigenetic mechanisms in diabetes mellitus (DM), β-cell reprogramming and its complications is an emerging concept. Recent evidence suggests that there is a link between DM and histone deacetylases (HDACs), because HDAC inhibitors promote β-cell differentiation, proliferation, function and improve insulin resistance. Moreover, gut microbes and diet-derived products can alter the host epigenome. Furthermore, butyrate and butyrate-producing microbes are decreased in DM. Butyrate is a short-chain fatty acid produced from the fermentation of dietary fibers by microbiota and has been proven as an HDAC inhibitor. The present review provides a pragmatic interpretation of chromatin-dependent and independent complex signaling/mechanisms of butyrate for the treatment of Type 1 and Type 2 DM, with an emphasis on the promising strategies for its drugability and therapeutic implication.

  17. Benzothiazole-containing hydroxamic acids as histone deacetylase inhibitors and antitumor agents.

    Science.gov (United States)

    Oanh, Dao Thi Kim; Hai, Hoang Van; Park, Sang Ho; Kim, Hyun-Jung; Han, Byung-Woo; Kim, Hyung-Sook; Hong, Jin-Tae; Han, Sang-Bae; Hue, Van Thi My; Nam, Nguyen-Hai

    2011-12-15

    Data from clinical studies indicate that inhibitors of Class I and Class II histone deacetylase (HDAC) enzymes show great promise for the treatment of cancer. Zolinza (SAHA, Zolinza) was recently approved by the FDA for the treatment of the cutaneous manifestations of cutaneous T-cell lymphoma. As a part of our ongoing effort to identify novel small molecules to target these important enzymes, we have prepared two series of benzothiazole-containing analogues of SAHA. It was found that several compounds with 6C-bridge linking benzothiazole moiety and hydroxamic functional groups showed good inhibition against HDAC3 and 4 at as low as 1 μg/ml and exhibited potent cytotoxicity against five cancer cell lines with average IC(50) values of as low as 0.81 μg/ml, almost equipotent to SAHA.

  18. Therapeutic Strategies to Enhance the Anticancer Efficacy of Histone Deacetylase Inhibitors

    Directory of Open Access Journals (Sweden)

    Claudia P. Miller

    2011-01-01

    Full Text Available Histone acetylation is a posttranslational modification that plays a role in regulating gene expression. More recently, other nonhistone proteins have been identified to be acetylated which can regulate their function, stability, localization, or interaction with other molecules. Modulating acetylation with histone deacetylase inhibitors (HDACi has been validated to have anticancer effects in preclinical and clinical cancer models. This has led to development and approval of the first HDACi, vorinostat, for the treatment of cutaneous T cell lymphoma. However, to date, targeting acetylation with HDACi as a monotherapy has shown modest activity against other cancers. To improve their efficacy, HDACi have been paired with other antitumor agents. Here, we discuss several combination therapies, highlighting various epigenetic drugs, ROS-generating agents, proteasome inhibitors, and DNA-damaging compounds that together may provide a therapeutic advantage over single-agent strategies.

  19. Structure-based virtual screening campaigns on curcuminoids as potent ligands for histone deacetylase-2

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    Enade Perdana Istyastono

    2016-03-01

    Full Text Available Curcumin was reported to reverse the decrease in histone deacetylase-2 (HDAC2 protein expression in inflammatory diseases of the lung, including chronic obstructive pulmonary disease (COPD, severe asthma, and asthma in smokers. This indicates that curcumin is a potent ligand for HDAC2. The construction and retrospective validation of a structure-based virtual screening (SBVS protocol to identify potent ligands for HDAC2 are presented in this article. The validated protocol was subsequently employed to screen curcumin and other curcuminoids found in Curcuma longa, i.e. demethoxy curcumin and bis-demethoxy curcumin, and to examine their interactions to HDAC2 in the atomic level. The results show that curcumin, demethoxy curcumin and bis-demethoxy curcumin are potent HDAC2 ligands. The insights from their interactions to HDAC2 resulted from the molecular docking simulations presented in this article could be employed further in the design and discovery potent HDAC2 ligands.

  20. Global Promoter Targeting of a Conserved Lysine Deacetylase for Transcriptional Shutoff during Quiescence Entry.

    Science.gov (United States)

    McKnight, Jeffrey N; Boerma, Joseph W; Breeden, Linda L; Tsukiyama, Toshio

    2015-09-01

    Quiescence is a conserved cell-cycle state characterized by cell-cycle arrest, increased stress resistance, enhanced longevity, and decreased transcriptional, translational, and metabolic output. Although quiescence plays essential roles in cell survival and normal differentiation, the molecular mechanisms leading to this state are not well understood. Here, we determined changes in the transcriptome and chromatin structure of S. cerevisiae upon quiescence entry. Our analyses revealed transcriptional shutoff that is far more robust than previously believed and an unprecedented global chromatin transition, which are tightly correlated. These changes require Rpd3 lysine deacetylase targeting to at least half of gene promoters via quiescence-specific transcription factors including Xbp1 and Stb3. Deletion of RPD3 prevents cells from establishing transcriptional quiescence, leading to defects in quiescence entry and shortening of chronological lifespan. Our results define a molecular mechanism for global reprogramming of transcriptome and chromatin structure for quiescence driven by a highly conserved chromatin regulator.

  1. Dynamic phosphorylation of Histone Deacetylase 1 by Aurora kinases during mitosis regulates zebrafish embryos development

    Science.gov (United States)

    Loponte, Sara; Segré, Chiara V.; Senese, Silvia; Miccolo, Claudia; Santaguida, Stefano; Deflorian, Gianluca; Citro, Simona; Mattoscio, Domenico; Pisati, Federica; Moser, Mirjam A.; Visintin, Rosella; Seiser, Christian; Chiocca, Susanna

    2016-01-01

    Histone deacetylases (HDACs) catalyze the removal of acetyl molecules from histone and non-histone substrates playing important roles in chromatin remodeling and control of gene expression. Class I HDAC1 is a critical regulator of cell cycle progression, cellular proliferation and differentiation during development; it is also regulated by many post-translational modifications (PTMs). Herein we characterize a new mitosis-specific phosphorylation of HDAC1 driven by Aurora kinases A and B. We show that this phosphorylation affects HDAC1 enzymatic activity and it is critical for the maintenance of a proper proliferative and developmental plan in a complex organism. Notably, we find that Aurora-dependent phosphorylation of HDAC1 regulates histone acetylation by modulating the expression of genes directly involved in the developing zebrafish central nervous system. Our data represent a step towards the comprehension of HDAC1 regulation by its PTM code, with important implications in unravelling its roles both in physiology and pathology. PMID:27458029

  2. Histone deacetylase 1 is required for the development of the zebrafish inner ear

    Science.gov (United States)

    He, Yingzi; Tang, Dongmei; Li, Wenyan; Chai, Renjie; Li, Huawei

    2016-01-01

    Histone deacetylase 1 (HDAC1) has been reported to be important for multiple aspects of normal embryonic development, but little is known about its function in the development of mechanosensory organs. Here, we first confirmed that HDAC1 is expressed in the developing otic vesicles of zebrafish by whole-mount in situ hybridization. Knockdown of HDAC1 using antisense morpholino oligonucleotides in zebrafish embryos induced smaller otic vesicles, abnormal otoliths, malformed or absent semicircular canals, and fewer sensory hair cells. HDAC1 loss of function also caused attenuated expression of a subset of key genes required for otic vesicle formation during development. Morpholino-mediated knockdown of HDAC1 resulted in decreased expression of members of the Fgf family in the otic vesicles, suggesting that HDAC1 is involved in the development of the inner ear through regulation of Fgf signaling pathways. Taken together, our results indicate that HDAC1 plays an important role in otic vesicle formation. PMID:26832938

  3. Plants Release Precursors of Histone Deacetylase Inhibitors to Suppress Growth of Competitors.

    Science.gov (United States)

    Venturelli, Sascha; Belz, Regina G; Kämper, Andreas; Berger, Alexander; von Horn, Kyra; Wegner, André; Böcker, Alexander; Zabulon, Gérald; Langenecker, Tobias; Kohlbacher, Oliver; Barneche, Fredy; Weigel, Detlef; Lauer, Ulrich M; Bitzer, Michael; Becker, Claude

    2015-11-01

    To secure their access to water, light, and nutrients, many plant species have developed allelopathic strategies to suppress competitors. To this end, they release into the rhizosphere phytotoxic substances that inhibit the germination and growth of neighbors. Despite the importance of allelopathy in shaping natural plant communities and for agricultural production, the underlying molecular mechanisms are largely unknown. Here, we report that allelochemicals derived from the common class of cyclic hydroxamic acid root exudates directly affect the chromatin-modifying machinery in Arabidopsis thaliana. These allelochemicals inhibit histone deacetylases both in vitro and in vivo and exert their activity through locus-specific alterations of histone acetylation and associated gene expression. Our multilevel analysis collectively shows how plant-plant interactions interfere with a fundamental cellular process, histone acetylation, by targeting an evolutionarily highly conserved class of enzymes.

  4. A circadian rhythm orchestrated by histone deacetylase 3 controls hepatic lipid metabolism

    DEFF Research Database (Denmark)

    Feng, Dan; Liu, Tao; Sun, Zheng;

    2011-01-01

    Disruption of the circadian clock exacerbates metabolic diseases, including obesity and diabetes. We show that histone deacetylase 3 (HDAC3) recruitment to the genome displays a circadian rhythm in mouse liver. Histone acetylation is inversely related to HDAC3 binding, and this rhythm is lost when...... HDAC3 is absent. Although amounts of HDAC3 are constant, its genomic recruitment in liver corresponds to the expression pattern of the circadian nuclear receptor Rev-erbα. Rev-erbα colocalizes with HDAC3 near genes regulating lipid metabolism, and deletion of HDAC3 or Rev-erbα in mouse liver causes...... hepatic steatosis. Thus, genomic recruitment of HDAC3 by Rev-erbα directs a circadian rhythm of histone acetylation and gene expression required for normal hepatic lipid homeostasis....

  5. Single-Molecule Electronic Measurements of the Dynamic Flexibility of Histone Deacetylases

    Science.gov (United States)

    Froberg, James; You, Seungyong; Yu, Junru; Haldar, Manas; Sedigh, Abbas; Mallik, Sanku; Srivastava, D. K.; Choi, Yongki

    Due to their involvement in epigenetic regulation, histone deacetylases (HDACs) have gained considerable interest in designing drugs for treatment of a variety of human diseases including cancers. Recently, we applied a label-free, electronic single-molecule nano-circuit technique to gain insight into the contribution of the dynamic flexibility in HDACs structure during the course of substrates/ ligands binding and catalysis. We observed that HDAC8 has two major (dynamically interconvertible) conformational states, ``ground (catalytically unfavorable)'' and ``transition (catalytically favorable)''. In addition, we found that its cognate substrates/ligands reciprocally catalyze the transition of the ground to the transition state conformation of HDAC8. Thus, we propose that both enzymes and their substrates/ligands serve as ``catalysts'' in facilitating the structural changes of each other and promoting the overall chemical transformation reaction. Such new information provides the potential for designing a new class of mechanism-based inhibitors and activators of HDAC8 for treating human diseases.

  6. Latent HIV in primary T lymphocytes is unresponsive to histone deacetylase inhibitors

    Directory of Open Access Journals (Sweden)

    Sahu Gautam K

    2011-08-01

    Full Text Available Abstract Recently, there is considerable interest in the field of anti-HIV therapy to identify and develop chromatin-modifying histone deacetylase (HDAC inhibitors that can effectively reactivate latent HIV in patients. The hope is that this would help eliminate cells harboring latent HIV and achieve an eventual cure of the virus. However, how effectively these drugs can stimulate latent HIVs in quiescent primary CD4 T cells, despite their relevant potencies demonstrated in cell line models of HIV latency, is not clear. Here, we show that the HDAC inhibitors valproic acid (VPA and trichostatin A (TSA are unable to reactivate HIV in latently infected primary CD4 T cells generated in the H80 co-culture system. This raises a concern that the drugs inhibiting HDAC function alone might not be sufficient for stimulating latent HIV in resting CD4 T cells in patients and not achieve any anticipated reduction in the pool of latent reservoirs.

  7. Overexpression of Histone Deacetylase 6 Enhances Resistance to Porcine Reproductive and Respiratory Syndrome Virus in Pigs

    Science.gov (United States)

    Li, Qiuyan; Li, Zhiguo; Wang, Meng; Liu, Lin; Tian, Kegong; Li, Ning

    2017-01-01

    Porcine reproductive and respiratory syndrome virus (PRRSV) is one of the most economically relevant viral pathogens in pigs and causes substantial losses in the pig industry worldwide each year. At present, PRRSV vaccines do not effectively prevent and control this disease. Consequently, it is necessary to develop new antiviral strategies to compensate for the inefficacy of the available vaccines. Histone deacetylase 6 (HDAC6) is an important member of the histone deacetylase family that is responsible for regulating many important biological processes. Studies have shown that HDAC6 has anti-viral activities during the viral life cycle. However, whether HDAC6 overexpression enhances resistance to PRRSV in pigs remains unknown. In this study, we used a somatic cell cloning method to produce transgenic (TG) pigs that constitutively overexpress porcine HDAC6. These TG pigs showed germ line transmission with continued overexpression of HDAC6. In vitro, virus-challenged porcine alveolar macrophages (PAMs) overexpressed HDAC6, which suppressed viral gene expression and PRRSV production. In vivo, resistance to PRRSV in TG pigs was evaluated by direct or cohabitation mediated infection with a highly pathogenic PRRSV (HP-PRRSV) strain. Compared with non-TG (NTG) siblings, TG pigs showed a significantly lower viral load in the lungs and an extended survival time after infection with HP-PRRSV via intramuscular injection. In the cohabitation study, NTG pigs housed with challenged NTG pigs exhibited significantly worse clinical symptoms than the other three in-contact groups. These results collectively suggest that HDAC6 overexpression enhances resistance to PRRSV infection both in vitro and in vivo. Our findings suggest the potential involvement of HDAC6 in the response to PRRSV, which will facilitate the development of novel therapies for PRRSV. PMID:28052127

  8. The Effects of Pharmacological Inhibition of Histone Deacetylase 3 (HDAC3 in Huntington's Disease Mice.

    Directory of Open Access Journals (Sweden)

    Haiqun Jia

    Full Text Available An important epigenetic modification in Huntington's disease (HD research is histone acetylation, which is regulated by histone acetyltransferase and histone deacetylase (HDAC enzymes. HDAC inhibitors have proven effective in HD model systems, and recent work is now focused on functional dissection of the individual HDAC enzymes in these effects. Histone deacetylase 3 (HDAC3, a member of the class I subfamily of HDACs, has previously been implicated in neuronal toxicity and huntingtin-induced cell death. Hence, we tested the effects of RGFP966 ((E-N-(2-amino-4-fluorophenyl-3-(1-cinnamyl-1H-pyrazol-4-ylacrylamide, a benzamide-type HDAC inhibitor that selectively targets HDAC3, in the N171-82Q transgenic mouse model of HD. We found that RGFP966 at doses of 10 and 25 mg/kg improves motor deficits on rotarod and in open field exploration, accompanied by neuroprotective effects on striatal volume. In light of previous studies implicating HDAC3 in immune function, we measured gene expression changes for 84 immune-related genes elicited by RGFP966 using quantitative PCR arrays. RGFP966 treatment did not cause widespread changes in cytokine/chemokine gene expression patterns, but did significantly alter the striatal expression of macrophage migration inhibitory factor (Mif, a hormone immune modulator associated with glial cell activation, in N171-82Q transgenic mice, but not WT mice. Accordingly, RGFP966-treated mice showed decreased glial fibrillary acidic protein (GFAP immunoreactivity, a marker of astrocyte activation, in the striatum of N171-82Q transgenic mice compared to vehicle-treated mice. These findings suggest that the beneficial actions of HDAC3 inhibition could be related, in part, with lowered Mif levels and its associated downstream effects.

  9. Autophagy-related cell death by pan-histone deacetylase inhibition in liver cancer

    Science.gov (United States)

    Di Fazio, Pietro; Waldegger, Petra; Jabari, Samir; Lingelbach, Susanne; Montalbano, Roberta; Ocker, Matthias; Slater, Emily P.; Bartsch, Detlef K.; Illig, Romana; Neureiter, Daniel; Wissniowski, Thaddeus T.

    2016-01-01

    Autophagy is a homeostatic, catabolic degradation process and cell fate essential regulatory mechanism. Protracted autophagy triggers cell death; its aberrant function is responsible for several malignancies. Panobinostat, a potent pan-deacetylase inhibitor, causes endoplasmic reticulum stress-induced cell death. The aim of this study was to investigate the role of autophagy in deacetylase inhibitor-triggered liver cancer cell death. HepG2 (p53wt) and Hep3B (p53 null) liver cancer cell lines were exposed to panobinostat. RT-qPCR and western blot confirmed autophagic factor modulation. Immuno-fluorescence, -precipitation and -histochemistry as well as transmission electron microscopy verified autophagosome formation. The cytotoxicity of panobinostat and autophagy modulators was detected using a real time cell viability assay. Panobinostat induced autophagy-related factor expression and aggregation. Map1LC3B and Beclin1 were significantly over-expressed in HepG2 xenografts in nude mice treated with panobinostat for 4 weeks. Subcellular distribution of Beclin1 increased with the appearance of autophagosomes-like aggregates. Cytosolic loss of p53, in HepG2, and p73, in Hep3B cells, and a corresponding gain of their nuclear level, together with modulation of DRAM1, were observed. Autophagosome aggregation was visible after 6 h of treatment. Treatment of cells stably expressing GFP-RFPtag Map1LC3B resulted in aggregation and a fluorescence switch, thus confirming autophagosome formation and maturation. Tamoxifen, an inducer of autophagy, caused only a block in cell proliferation; but in combination with panobinostat it resulted in cell death. Autophagy triggers cell demise in liver cancer. Its modulation by the combination of tamoxifen and panobinostat could be a new option for palliative treatment of hepatocellular carcinoma. PMID:27058414

  10. Detrimental effect of class-selective histone deacetylase inhibitors during tissue regeneration following hindlimb ischemia.

    Science.gov (United States)

    Spallotta, Francesco; Tardivo, Silvia; Nanni, Simona; Rosati, Jessica D; Straino, Stefania; Mai, Antonello; Vecellio, Matteo; Valente, Sergio; Capogrossi, Maurizio C; Farsetti, Antonella; Martone, Julie; Bozzoni, Irene; Pontecorvi, Alfredo; Gaetano, Carlo; Colussi, Claudia

    2013-08-09

    Histone deacetylase inhibitors (DIs) are promising drugs for the treatment of several pathologies including ischemic and failing heart where they demonstrated efficacy. However, adverse side effects and cardiotoxicity have also been reported. Remarkably, no information is available about the effect of DIs during tissue regeneration following acute peripheral ischemia. In this study, mice made ischemic by femoral artery excision were injected with the DIs MS275 and MC1568, selective for class I and IIa histone deacetylases (HDACs), respectively. In untreated mice, soon after damage, class IIa HDAC phosphorylation and nuclear export occurred, paralleled by dystrophin and neuronal nitric-oxide synthase (nNOS) down-regulation and decreased protein phosphatase 2A activity. Between 14 and 21 days after ischemia, dystrophin and nNOS levels recovered, and class IIa HDACs relocalized to the nucleus. In this condition, the MC1568 compound increased the number of newly formed muscle fibers but delayed their terminal differentiation, whereas MS275 abolished the early onset of the regeneration process determining atrophy and fibrosis. The selective DIs had differential effects on the vascular compartment: MC1568 increased arteriogenesis whereas MS275 inhibited it. Capillarogenesis did not change. Chromatin immunoprecipitations revealed that class IIa HDAC complexes bind promoters of proliferation-associated genes and of class I HDAC1 and 2, highlighting a hierarchical control between class II and I HDACs during tissue regeneration. Our findings indicate that class-selective DIs interfere with normal mouse ischemic hindlimb regeneration and suggest that their use could be limited by alteration of the regeneration process in peripheral ischemic tissues.

  11. Removal of dyes from water using chitosan hydrogel/SiO2 and chitin hydrogel/SiO2 hybrid materials obtained by the sol-gel method.

    Science.gov (United States)

    Copello, Guillermo J; Mebert, Andrea M; Raineri, M; Pesenti, Mariela P; Diaz, Luis E

    2011-02-15

    This work describes the synthesis of chitosan hydrogel/SiO(2) and chitin hydrogel/SiO(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 (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 (ΔG(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(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.

  12. 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.

  13. Muscle histone deacetylase 4 upregulation in amyotrophic lateral sclerosis: potential role in reinnervation ability and disease progression.

    Science.gov (United States)

    Bruneteau, Gaëlle; Simonet, Thomas; Bauché, Stéphanie; Mandjee, Nathalie; Malfatti, Edoardo; Girard, Emmanuelle; Tanguy, Marie-Laure; Behin, Anthony; Khiami, Frédéric; Sariali, Elhadi; Hell-Remy, Caroline; Salachas, François; Pradat, Pierre-François; Fournier, Emmanuel; Lacomblez, Lucette; Koenig, Jeanine; Romero, Norma Beatriz; Fontaine, Bertrand; Meininger, Vincent; Schaeffer, Laurent; Hantaï, Daniel

    2013-08-01

    Amyotrophic lateral sclerosis is a typically rapidly progressive neurodegenerative disorder affecting motor neurons leading to progressive muscle paralysis and death, usually from respiratory failure, in 3-5 years. Some patients have slow disease progression and prolonged survival, but the underlying mechanisms remain poorly understood. Riluzole, the only approved treatment, only modestly prolongs survival and has no effect on muscle function. In the early phase of the disease, motor neuron loss is initially compensated for by collateral reinnervation, but over time this compensation fails, leading to progressive muscle wasting. The crucial role of muscle histone deacetylase 4 and its regulator microRNA-206 in compensatory reinnervation and disease progression was recently suggested in a mouse model of amyotrophic lateral sclerosis (transgenic mice carrying human mutations in the superoxide dismutase gene). Here, we sought to investigate whether the microRNA-206-histone deacetylase 4 pathway plays a role in muscle compensatory reinnervation in patients with amyotrophic lateral sclerosis and thus contributes to disease outcome differences. We studied muscle reinnervation using high-resolution confocal imaging of neuromuscular junctions in muscle samples obtained from 11 patients with amyotrophic lateral sclerosis, including five long-term survivors. We showed that the proportion of reinnervated neuromuscular junctions was significantly higher in long-term survivors than in patients with rapidly progressive disease. We analysed the expression of muscle candidate genes involved in the reinnervation process and showed that histone deacetylase 4 upregulation was significantly greater in patients with rapidly progressive disease and was negatively correlated with the extent of muscle reinnervation and functional outcome. Conversely, the proposed regulator of histone deacetylase 4, microRNA-206, was upregulated in both patient groups, but did not correlate with disease

  14. 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.

  15. 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.

  16. 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.

  17. Regulation of Retinoic Acid Inducible Gene-I (RIG-I Activation by the Histone Deacetylase 6

    Directory of Open Access Journals (Sweden)

    Helene Minyi Liu

    2016-07-01

    Full Text Available Retinoic acid inducible gene-I (RIG-I is a cytosolic pathogen recognition receptor that initiates the immune response against many RNA viruses. Upon RNA ligand binding, RIG-I undergoes a conformational change facilitating its homo-oligomerization and activation that results in its translocation from the cytosol to intracellular membranes to bind its signaling adaptor protein, mitochondrial antiviral-signaling protein (MAVS. Here we show that RIG-I activation is regulated by reversible acetylation. Acetyl-mimetic mutants of RIG-I do not form virus-induced homo-oligomers, revealing that acetyl-lysine residues of the RIG-I repressor domain prevent assembly to active homo-oligomers. During acute infection, deacetylation of RIG-I promotes its oligomerization upon ligand binding. We identify histone deacetylase 6 (HDAC6 as the deacetylase that promotes RIG-I activation and innate antiviral immunity to recognize and restrict RNA virus infection.

  18. H3K9me-independent gene silencing in fission yeast heterochromatin by Clr5 and histone deacetylases

    DEFF Research Database (Denmark)

    Hansen, Klavs R; Hazan, Idit; Shanker, Sreenath;

    2011-01-01

    Nucleosomes in heterochromatic regions bear histone modifications that distinguish them from euchromatic nucleosomes. Among those, histone H3 lysine 9 methylation (H3K9me) and hypoacetylation have been evolutionarily conserved and are found in both multicellular eukaryotes and single-cell model......-characterized heterochromatic region, is hardly affected in cells lacking the H3K9 methyltransferase Clr4. We document the existence of a pathway parallel to H3K9me ensuring gene repression in the absence of Clr4 and identify a silencing factor central to this pathway, Clr5. We find that Clr5 controls gene expression......, our results point to histone deacetylases as prominent repressors of gene expression in fission yeast heterochromatin. These deacetylases can act in concert with, or independently of, the widely studied H3K9me mark to influence gene silencing at heterochromatic loci....

  19. Arabidopsis DNA methyltransferase AtDNMT2 associates with histone deacetylase AtHD2s activity

    Energy Technology Data Exchange (ETDEWEB)

    Song, Yuan [Key Laboratory of Arid and Grassland Agroecology, Ministry of Education, School of Life Science, Lanzhou University, Lanzhou 730000 (China); Southern Crop Protection and Food Research Centre, Agriculture and Agri-Food Canada, 1391 Sandford Street, London, ON, Canada N5V4T3 (Canada); Wu, Keqiang [Institute of Plant Biology, National Taiwan University, Taipei 106, Taiwan (China); Dhaubhadel, Sangeeta [Southern Crop Protection and Food Research Centre, Agriculture and Agri-Food Canada, 1391 Sandford Street, London, ON, Canada N5V4T3 (Canada); An, Lizhe, E-mail: lizhean@lzu.edu.cn [Key Laboratory of Arid and Grassland Agroecology, Ministry of Education, School of Life Science, Lanzhou University, Lanzhou 730000 (China); Tian, Lining, E-mail: tianl@agr.gc.ca [Southern Crop Protection and Food Research Centre, Agriculture and Agri-Food Canada, 1391 Sandford Street, London, ON, Canada N5V4T3 (Canada)

    2010-05-28

    DNA methyltransferase2 (DNMT2) is always deemed to be enigmatic, because it contains highly conserved DNA methyltransferase motifs but lacks the DNA methylation catalytic capability. Here we show that Arabidopsis DNA methyltransferase2 (AtDNMT2) is localized in nucleus and associates with histone deacetylation. Bimolecular fluorescence complementation and pull-down assays show AtDNMT2 interacts with type-2 histone deacetylases (AtHD2s), a unique type of histone deacetylase family in plants. Through analyzing the expression of AtDNMT2: ss-glucuronidase (GUS) fusion protein, we demonstrate that AtDNMT2 has the ability to repress gene expression at transcription level. Meanwhile, the expression of AtDNMT2 gene is altered in athd2c mutant plants. We propose that AtDNMT2 possibly involves in the activity of histone deacetylation and plant epigenetic regulatory network.

  20. Histone deacetylase 1, 2, 6 and acetylated histone H4 in B- and T-cell lymphomas

    DEFF Research Database (Denmark)

    Marquard, L.; Poulsen, C.B.; Gjerdrum, L.M.;

    2009-01-01

    AIMS: Histone deacetylase (HDAC) inhibitors are novel therapeutics in the treatment of peripheral T-cell lymphoma, unspecified (PTCL) and diffuse large B-cell lymphoma (DLBCL), where, for unknown reasons, T-cell malignancies appear to be more sensitive than B-cell malignancies. The aim was to det......AIMS: Histone deacetylase (HDAC) inhibitors are novel therapeutics in the treatment of peripheral T-cell lymphoma, unspecified (PTCL) and diffuse large B-cell lymphoma (DLBCL), where, for unknown reasons, T-cell malignancies appear to be more sensitive than B-cell malignancies. The aim...... was to determine HDAC expression in DLBCL and PTCL which has not previously been investigated. METHODS AND RESULTS: The expression of HDAC1, HDAC2, HDAC6 and acetylated histone H4 was examined immunohistochemically in 31 DLBCL and 45 PTCL. All four markers showed high expression in both DLBCL and PTCL compared...

  1. Generation of Reactive Oxygen Species during Apoptosis Induced by DNA-Damaging Agents and/or Histone Deacetylase Inhibitors

    Directory of Open Access Journals (Sweden)

    Barbora Brodská

    2011-01-01

    Full Text Available Reactive oxygen species play an important role in the process of apoptosis in many cell types. In this paper, we analyzed the role of ROS in DNA-damaging agents (actinomycin D or decitabine, which induced apoptosis of leukemia cell line CML-T1 and normal peripheral blood lymphocytes (PBL. The possibility of synergism with histone deacetylase inhibitors butyrate or SAHA is also reported. We found that in cancer cell line, ROS production significantly contributed to apoptosis triggering, while in normal lymphocytes treated by cytostatic or cytotoxic drugs, necrosis as well as apoptosis occurred and large heterogeneity of ROS production was measured. Combined treatment with histone deacetylase inhibitor did not potentiate actinomycin D action, whereas combination of decitabine and SAHA brought synergistic ROS generation and apoptotic features in CML cell line. Appropriate decrease of cell viability indicated promising therapeutic potential of this combination in CML, but side effects on normal PBL should be taken into attention.

  2. 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.

  3. 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.

  4. 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

    , 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...... 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...

  5. On the mechanism of penetration of ovicidal fungi through egg-shells of parasitic nematodes. Decomposition of chitinous and ascaroside layers.

    Science.gov (United States)

    Kunert, J

    1992-01-01

    The decomposition of egg-shells of Ascaris lumbricoides L. was studied microscopically using topochemical methods in a set of 32 strains of soil ovicidal fungi. It was found that even fungi displaying minimal chitinolytic activity in tests on purified chitin in vitro are able to dissolve chitin of egg-shells during the attack on live eggs. Fungi without any chitinolytic activity penetrate probably only the mechanically damaged eggs. None of the studied fungi was capable of degrading enzymatically the glycolipid (ascaroside) layer of the egg-shell which remained intact after digestion of all other components of the egg.

  6. Design and Synthesis of Novel 2, 5-Disubstituted-1, 3, 4-Thiadiazoles and Oxadiazoles as Histone Deacetylase Inhibitors

    OpenAIRE

    Somani, Rakesh R.; Madhuri H. Jain; Parin K. Vora; Pallavi M. Patil; Sonali S. Parab

    2016-01-01

    Histone deacetylases (HDACs) have been widely recognized as promising targets for cancer treatment. Accumulated clinical studies have demonstrated that HDACs inhibitors show great potential for the treatment of cancer. SAHA (Vorinostat, trade name Zolinza®) and Trichostatin A (TSA) where approved by the FDA in 2006 for the treatment of the cutaneous manifestations of cutaneous T-cell lymphoma. As a continuity of our ongoing effort to identify novel small molecules targeting these important en...

  7. The POZ/BTB protein NAC1 interacts with two different histone deacetylases in neuronal-like cultures.

    Science.gov (United States)

    Korutla, L; Wang, P J; Mackler, S A

    2005-08-01

    NAC1 is a cocaine-regulated POZ/BTB (Pox virus and Zinc finger/Bric-a-brac Tramtrack Broad complex) protein. NAC1 is increased by cocaine selectively in the nucleus accumbens, a CNS region important for drug addiction. NAC1's role in the cell, however, is not known. Each of the two NAC1 isoforms, sNAC1 (short NAC1) and lNAC1 (long NAC1), may serve as corepressors for other POZ/BTB proteins. This study investigated whether sNAC1 and lNAC1 demonstrated protein-protein interactions with other corepressors. Histone deacetylase (HDAC) inhibition reversed sNAC1 and lNAC1 repression of Gal4 luciferase, but only in neuronal-like cultures. Because these inhibitors do not distinguish among histone deacetylases, two histone deacetylases were selected for further study. HDAC 3 and 4 both demonstrated protein-protein interactions with sNAC1 and lNAC1. This was shown using coimmunoprecipitations, glutathione-S-transferase (GST) pulldowns and mammalian two-hybrids. Importantly, either the POZ domain or NAC1 without the POZ domain can bind these two HDACs. Other corepressors, specifically NCoR (nuclear receptor corepressor), SMRT (silencing mediator for retinoid and thyroid hormone receptor) and mSin3a, do not exhibit protein-protein interactions with sNAC1 and lNAC1. None showed protein-protein interactions in GST pulldowns or mammalian two-hybrids. Taken together, the results of these experiments indicate sNAC1 and lNAC1 recruit histone deacetylases for transcriptional repression, further enhancing POZ/BTB protein mediated repression.

  8. HdaA, a Major Class 2 Histone Deacetylase of Aspergillus nidulans, Affects Growth under Conditions of Oxidative Stress

    OpenAIRE

    Tribus, Martin; Galehr, Johannes; Trojer, Patrick; Brosch, Gerald; Loidl, Peter; Marx, Florentine; Haas, Hubertus; Graessle, Stefan

    2005-01-01

    Histone deacetylases (HDACs) catalyze the removal of acetyl groups from the ɛ-amino group of distinct lysine residues in the amino-terminal tail of core histones. Since the acetylation status of core histones plays a crucial role in fundamental processes in eukaryotic organisms, such as replication and regulation of transcription, recent research has focused on the enzymes responsible for the acetylation/deacetylation of core histones. Very recently, we showed that HdaA, a member of the Sacch...

  9. Deacetylase inhibitors repress STAT5-mediated transcription by interfering with bromodomain and extra-terminal (BET) protein function.

    Science.gov (United States)

    Pinz, Sophia; Unser, Samy; Buob, Dominik; Fischer, Philipp; Jobst, Belinda; Rascle, Anne

    2015-04-20

    Signal transducer and activator of transcription STAT5 is essential for the regulation of proliferation and survival genes. Its activity is tightly regulated through cytokine signaling and is often upregulated in cancer. We showed previously that the deacetylase inhibitor trichostatin A (TSA) inhibits STAT5-mediated transcription by preventing recruitment of the transcriptional machinery at a step following STAT5 binding to DNA. The mechanism and factors involved in this inhibition remain unknown. We now show that deacetylase inhibitors do not target STAT5 acetylation, as we initially hypothesized. Instead, they induce a rapid increase in global histone acetylation apparently resulting in the delocalization of the bromodomain and extra-terminal (BET) protein Brd2 and of the Brd2-associated factor TBP to hyperacetylated chromatin. Treatment with the BET inhibitor (+)-JQ1 inhibited expression of STAT5 target genes, supporting a role of BET proteins in the regulation of STAT5 activity. Accordingly, chromatin immunoprecipitation demonstrated that Brd2 is associated with the transcriptionally active STAT5 target gene Cis and is displaced upon TSA treatment. Our data therefore indicate that Brd2 is required for the proper recruitment of the transcriptional machinery at STAT5 target genes and that deacetylase inhibitors suppress STAT5-mediated transcription by interfering with Brd2 function.

  10. Histone deacetylase inhibitors inducing human cervical cancer cell apoptosis by decreasing DNA-methyltransferase 3B

    Institute of Scientific and Technical Information of China (English)

    LIU Ning; ZHAO Li-jun; LI Xiao-ping; WANG Jian-liu; CHAI Guo-lin; WEI Li-hui

    2012-01-01

    Background Histone deacetylase (HDAC) inhibitors are a group of small chemical molecules that inhibit histone deacetylase.At cell level,HDAC inhibitors have multiple biological effects such as cell cycle arrest,apoptosis,cell differentiation and auotophagy.At molecular level,HDAC inhibitors cause histone and nonhistone acetylation and induce gene expression.HDAC inhibitors are widely used in cancer therapy because of its function of inducing apoptosis.However,the mechanisms of apoptosis effect are not fully understood.TSA is a classical HDAC inhibitor and widely used in epigenetic and anti-cancer research.In this study,we selected Trichostatin A (TSA) to investigate the mechanisms of HDAC inhibitors apoptotic effect on cancer cells.Methods Cervical cancer cell lines such as Hela,Caski and normal human keratinocyte line HaCaT were treated with various concentrations of TSA.Crystal violent assay and 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay were performed to determine cell number.PARP cleavage and FITC-AnexinV were performed to determine apoptosis.DNA-methyltransferase (DNMT)1,DNMT3A and DNMT3B were determined by regular PCR,qPCR and Western Blotting.Small interfering RNA (SiRNAi) was used to knock down DNMT3B.Results HDAC inhibitors only induce cervical cancer cell apoptosis.At 1 μmol/L of TSA,86% of Hela cell and 76% of Caski went apoptosis.For normal cells,HDAC inhibitors have no cytotoxic effect at therapeutic dosage,(90.0±8.4)% of normal cell survive after treated with 1 μmol/L of TSA.We compared 1 μmol/L group with untreated control with t-test.There was no significance between 1 μmol/L group and untreated control for normal cell (P >0.05).HDAC inhibitors decreased DNMT3B in cancer cell but not in normal cell.Manually knock-down of DNMT3B induced Hela and Caski cell apoptosis.More than 99% of Hela and Caski cell went apoptosis after deprived of DNMT3B.Conclusions DNMT3B was essential to cervical cancer cell survival

  11. Gene profile analysis of osteoblast genes differentially regulated by histone deacetylase inhibitors

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    Lamblin Anne-Francoise

    2007-10-01

    Full Text Available Abstract Background Osteoblast differentiation requires the coordinated stepwise expression of multiple genes. Histone deacetylase inhibitors (HDIs accelerate the osteoblast differentiation process by blocking the activity of histone deacetylases (HDACs, which alter gene expression by modifying chromatin structure. We previously demonstrated that HDIs and HDAC3 shRNAs accelerate matrix mineralization and the expression of osteoblast maturation genes (e.g. alkaline phosphatase, osteocalcin. Identifying other genes that are differentially regulated by HDIs might identify new pathways that contribute to osteoblast differentiation. Results To identify other osteoblast genes that are altered early by HDIs, we incubated MC3T3-E1 preosteoblasts with HDIs (trichostatin A, MS-275, or valproic acid for 18 hours in osteogenic conditions. The promotion of osteoblast differentiation by HDIs in this experiment was confirmed by osteogenic assays. Gene expression profiles relative to vehicle-treated cells were assessed by microarray analysis with Affymetrix GeneChip 430 2.0 arrays. The regulation of several genes by HDIs in MC3T3-E1 cells and primary osteoblasts was verified by quantitative real-time PCR. Nine genes were differentially regulated by at least two-fold after exposure to each of the three HDIs and six were verified by PCR in osteoblasts. Four of the verified genes (solute carrier family 9 isoform 3 regulator 1 (Slc9a3r1, sorbitol dehydrogenase 1, a kinase anchor protein, and glutathione S-transferase alpha 4 were induced. Two genes (proteasome subunit, beta type 10 and adaptor-related protein complex AP-4 sigma 1 were suppressed. We also identified eight growth factors and growth factor receptor genes that are significantly altered by each of the HDIs, including Frizzled related proteins 1 and 4, which modulate the Wnt signaling pathway. Conclusion This study identifies osteoblast genes that are regulated early by HDIs and indicates pathways that

  12. Chidamide, a novel histone deacetylase inhibitor, inhibits the viability of MDS and AML cells by suppressing JAK2/STAT3 signaling

    Science.gov (United States)

    Zhao, Sida; Guo, Juan; Zhao, Youshan; Fei, Chengming; Zheng, Qingqing; Li, Xiao; Chang, Chunkang

    2016-01-01

    Many studies have indicated that histone deacetylase (HDAC) activity is always increased in a lot of human tumors, and inhibition of HDAC activity is a promising new strategy in the treatment of cancers. Chidamide, a novel HDAC inhibitor of the benzamide class, is currently under clinical trials. In this study, we aimed to investigate the antitumor activity of Chidamide on myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML) cell lines and explore the possible mechanism. Chidamide exhibited efficient anti-proliferative activity on MDS and AML cells in a time- and dose-dependent manner, accompanied by cell cycle arrest at G0/G1 phase and cell apoptosis. Importantly, Chidamide possessed potent HDAC inhibition property, as evaluated by HDAC activity analysis and acetylation of histone H3 and H4. Moreover, Chidamide significantly increased the expression of Suppressors of cytokine signaling 3 (SOCS3), reduced the expression of Janus activated kinases 2 (JAK2) and Signal transducer and activator of transcription 3 (STAT3), and inhibited STAT3 downstream genes, including c-Myc, Bcl-xL, and Mcl-1, which are involved in cell cycle progression and anti-apoptosis. Therefore, we demonstrate that Chidamide exhibits potent inhibitory effect on cell viability of MDS and AML cells, and the possible mechanism may lie in the downregulation of JAK2/STAT3 signaling through SOCS3 upregulation. Our data provide rationale for clinical investigations of Chidamide in MDS and AML. PMID:27508038

  13. Utilization of Boron Compounds for the Modification of Suberoyl Anilide Hydroxamic Acid as Inhibitor of Histone Deacetylase Class II Homo sapiens.

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    Bakri, Ridla; Parikesit, Arli Aditya; Satriyanto, Cipta Prio; Kerami, Djati; Tambunan, Usman Sumo Friend

    2014-01-01

    Histone deacetylase (HDAC) has a critical function in regulating gene expression. The inhibition of HDAC has developed as an interesting anticancer research area that targets biological processes such as cell cycle, apoptosis, and cell differentiation. In this study, an HDAC inhibitor that is available commercially, suberoyl anilide hydroxamic acid (SAHA), has been modified to improve its efficacy and reduce the side effects of the compound. Hydrophobic cap and zinc-binding group of these compounds were substituted with boron-based compounds, whereas the linker region was substituted with p-aminobenzoic acid. The molecular docking analysis resulted in 8 ligands with ΔG binding value more negative than the standards, SAHA and trichostatin A (TSA). That ligands were analyzed based on the nature of QSAR, pharmacological properties, and ADME-Tox. It is conducted to obtain a potent inhibitor of HDAC class II Homo sapiens. The screening process result gave one best ligand, Nova2 (513246-99-6), which was then further studied by molecular dynamics simulations.

  14. THE SWELLING PROPERTIES OF SOIL ORGANIC MATTER AND THEIR RELATION TO SORPTION OF NON-IONIC ORGANIC COMPOUNDS

    Science.gov (United States)

    A method has been developed to measure the swelling properties of Concentrated natural organic materials in various organic liquids, and has been applied to various eat, pollen, chitin and cellulose samples. The swelling of these macromolecular aterials is rhe volumetric manifest...

  15. 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.

  16. New insights into the structure and mode of action of Mo-CBP3, an antifungal chitin-binding protein of Moringa oleifera seeds.

    Science.gov (United States)

    Batista, Adelina B; Oliveira, José T A; Gifoni, Juliana M; Pereira, Mirella L; Almeida, Marina G G; Gomes, Valdirene M; Da Cunha, Maura; Ribeiro, Suzanna F F; Dias, Germana B; Beltramini, Leila M; Lopes, José Luiz S; Grangeiro, Thalles B; Vasconcelos, Ilka M

    2014-01-01

    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. Biomedical Exploitation of Chitin and Chitosan via Mechano-Chemical Disassembly, Electrospinning, Dissolution in Imidazolium Ionic Liquids, and Supercritical Drying

    Science.gov (United States)

    Muzzarelli, Riccardo A. A.

    2011-01-01

    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. PMID:22131955

  18. Identification and Molecular Characterization of a Chitin-Binding Protein from the Beet Webworm, Loxostege sticticalis L.

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    Jiao Yin

    2014-10-01

    Full Text Available As the first crucial barrier in the midgut of insects, the peritrophic membrane (PM plays an important role in preventing external invasion. PM proteins, as the major components of the PM, determine the structure and function of this membrane. A new PM protein, named LstiCBP, from the PM of Loxostege sticticalis larvae was identified using cDNA library screening. The full cDNA of LstiCBP is 2606 bp in length and contains a 2403 bp ORF that encodes an 808-amino acid preprotein with a 15-amino acid as signal peptide. The deduced protein sequence of the cDNA contains 8 cysteine-rich chitin-binding domains (CBDs. Recombinant LstiCBP was successfully expressed in BL21 cells using recombinant plasmid DNA and showed high chitin-binding activity. LstiCBP expression was detected in the midgut at both the transcriptional and translational levels; however, the biochemical and physiological functions of LstiCBP in L. sticticalis require further investigation.

  19. 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.

  20. Kinetic characterization of Aspergillus niger chitinase CfcI using a HPAEC-PAD method for native chitin oligosaccharides.

    Science.gov (United States)

    van Munster, Jolanda M; Sanders, Peter; ten Kate, Geralt A; Dijkhuizen, Lubbert; van der Maarel, Marc J E C

    2015-04-30

    The abundant polymer chitin can be degraded by chitinases (EC 3.2.1.14) and β-N-acetyl-hexosaminidases (EC 3.2.1.52) to oligosaccharides and N-acetyl-glucosamine (GlcNAc) monomers. Kinetic characterization of these enzymes requires product quantification by an assay method with a low detection limit, preferably compatible with the use of native, non-labeled substrates. Here we report a quantitative HPAEC-PAD method that allows fast separation of chitin oligosaccharides (COS) ranging from (GlcNac)1-6 at detection limits of 1-3 pmol and a linear range of 5-250 pmol. Quantification under intra- and interday precision conditions was performed with 2.1-5.4% relative standard deviation (RSD) and 1.2-10.3% RSD, respectively. This method was successfully used for the determination of the kinetic parameters of the Aspergillus niger chitinase CfcI with native COS. CfcI was recently shown to release GlcNAc from the reducing end of COS, a new activity for fungal chitinases. A Carbohydrate Binding Module of family 18 (CBM18) is inserted in the CfcI catalytic domain. Site directed mutagenesis was used to assess the functionality of this CfcI-CBM18: four of its key amino acids were replaced by glycine residues, yielding CfcISYNF. Comparison of the kinetic parameters of CfcI and CfcISYNF confirmed that this CBM18 is functionally involved in catalysis.

  1. Preparation of zwitterionically charged nanocrystals by surface TEMPO-mediated oxidation and partial deacetylation of α-chitin.

    Science.gov (United States)

    Ifuku, Shinsuke; Hori, Taishi; Izawa, Hironori; Morimoto, Minoru; Saimoto, Hiroyuki

    2015-05-20

    Zwitterionic nanocrystals were prepared by TEMPO-mediated oxidation, partial deacetylation, and subsequent mechanical disintegration of α-chitin. The pH dependence of the morphology, transparency, and viscosity of the nanocrystals were evaluated. After those reactions, the carboxylate and amino group contents of the chitin derivative were 0.45 and 1.26 mmol/g, respectively. After mechanical treatment, the water dispersion consisted of nanocrystals approximately 250 nm long and 10nm thick. Under acidic and basic conditions, the water dispersions were highly transparent. On the other hand, under neutral conditions, the dispersion was turbid due to the ionic interaction between the cationic and anionic groups on the nanocrystal surface. Although the surface zwitterionic nanocrystals collected from acidic and basic dispersion were randomly oriented due to electrostatic repulsions, nanocrystals formed aggregates in neutral water due to the cationic and anionic interaction between them. Nanocrystals in neutral water had higher viscosity than those in acidic and basic water, since ionic interaction caused nanocrystal networks to form in water.

  2. Interference of the Histone Deacetylase Inhibits Pollen Germination and Pollen Tube Growth in Picea wilsonii Mast.

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    Yaning Cui

    Full Text Available Histone deacetylase (HDAC is a crucial component in the regulation of gene expression in various cellular processes in animal and plant cells. HDAC has been reported to play a role in embryogenesis. However, the effect of HDAC on androgamete development remains unclear, especially in gymnosperms. In this study, we used the HDAC inhibitors trichostatin A (TSA and sodium butyrate (NaB to examine the role of HDAC in Picea wilsonii pollen germination and pollen tube elongation. Measurements of the tip-focused Ca2+ gradient revealed that TSA and NaB influenced this gradient. Immunofluorescence showed that actin filaments were disrupted into disorganized fragments. As a result, the vesicle trafficking was disturbed, as determined by FM4-64 labeling. Moreover, the distribution of pectins and callose in cell walls was significantly altered in response to TSA and NaB. Our results suggest that HDAC affects pollen germination and polarized pollen tube growth in Picea wilsonii by affecting the intracellular Ca2+ concentration gradient, actin organization patterns, vesicle trafficking, as well as the deposition and configuration of cell wall components.

  3. Complex molecular mechanisms cooperate to mediate histone deacetylase inhibitors anti-tumour activity in neuroblastoma cells

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    Nardou Katya

    2008-06-01

    Full Text Available Abstract Background Histone deacetylase inhibitors (HDACi are a new class of promising anti-tumour agent inhibiting cell proliferation and survival in tumour cells with very low toxicity toward normal cells. Neuroblastoma (NB is the second most common solid tumour in children still associated with poor outcome in higher stages and, thus NB strongly requires novel treatment modalities. Results We show here that the HDACi Sodium Butyrate (NaB, suberoylanilide hydroxamic acid (SAHA and Trichostatin A (TSA strongly reduce NB cells viability. The anti-tumour activity of these HDACi involved the induction of cell cycle arrest in the G2/M phase, followed by the activation of the intrinsic apoptotic pathway, via the activation of the caspases cascade. Moreover, HDACi mediated the activation of the pro-apoptotic proteins Bid and BimEL and the inactivation of the anti-apoptotic proteins XIAP, Bcl-xL, RIP and survivin, that further enhanced the apoptotic signal. Interestingly, the activity of these apoptosis regulators was modulated by several different mechanisms, either by caspases dependent proteolytic cleavage or by degradation via the proteasome pathway. In addition, HDACi strongly impaired the hypoxia-induced secretion of VEGF by NB cells. Conclusion HDACi are therefore interesting new anti-tumour agents for targeting highly malignant tumours such as NB, as these agents display a strong toxicity toward aggressive NB cells and they may possibly reduce angiogenesis by decreasing VEGF production by NB cells.

  4. Histone deacetylases 1 and 2 regulate autophagy flux and skeletal muscle homeostasis in mice

    Science.gov (United States)

    Moresi, Viviana; Carrer, Michele; Grueter, Chad E.; Rifki, Oktay F.; Shelton, John M.; Richardson, James A.; Bassel-Duby, Rhonda; Olson, Eric N.

    2012-01-01

    Maintenance of skeletal muscle structure and function requires efficient and precise metabolic control. Autophagy plays a key role in metabolic homeostasis of diverse tissues by recycling cellular constituents, particularly under conditions of caloric restriction, thereby normalizing cellular metabolism. Here we show that histone deacetylases (HDACs) 1 and 2 control skeletal muscle homeostasis and autophagy flux in mice. Skeletal muscle-specific deletion of both HDAC1 and HDAC2 results in perinatal lethality of a subset of mice, accompanied by mitochondrial abnormalities and sarcomere degeneration. Mutant mice that survive the first day of life develop a progressive myopathy characterized by muscle degeneration and regeneration, and abnormal metabolism resulting from a blockade to autophagy. HDAC1 and HDAC2 regulate skeletal muscle autophagy by mediating the induction of autophagic gene expression and the formation of autophagosomes, such that myofibers of mice lacking these HDACs accumulate toxic autophagic intermediates. Strikingly, feeding HDAC1/2 mutant mice a high-fat diet from the weaning age releases the block in autophagy and prevents myopathy in adult mice. These findings reveal an unprecedented and essential role for HDAC1 and HDAC2 in maintenance of skeletal muscle structure and function and show that, at least in some pathological conditions, myopathy may be mitigated by dietary modifications. PMID:22307625

  5. Silencing of Histone Deacetylase 9 Expression in Podocytes Attenuates Kidney Injury in Diabetic Nephropathy

    Science.gov (United States)

    Liu, Feng; Zong, Ming; Wen, Xiaofei; Li, Xuezhu; Wang, Jun; Wang, Yi; Jiang, Wei; Li, Xiaojun; Guo, Zhongliang; Qi, Hualin

    2016-01-01

    Podocyte dysfunction is important in the onset and development of diabetic nephropathy (DN). Histone deacetylases (HDACs) have been recently proved to play critical roles in the pathogenesis of DN. As one subtype of the class IIa HDACs, HDAC9 is capable to repress/de-repress their target genes in tumor, inflammation, atherosclerosis and metabolic diseases. In the present study, we investigate whether HDAC9 is involved in the pathophysiologic process of DN, especially the podocyte injury. Firstly, we explored the expression patterns and localization of HDAC9 and found that HDAC9 expression was significantly up-regulated in high glucose (HG)-treated mouse podocytes, as well as kidney tissues from diabetic db/db mice and patients with DN. Secondly, knockdown of HDAC9 in mouse podocytes significantly suppressed HG-induced reactive oxygen species (ROS) generation, cell apoptosis and inflammation through JAK2/STAT3 pathway and reduced the podocytes injury by decreasing the expression levels of Nephrin and Podocin. Moreover, in diabetic db/db mice, silencing of HDAC9 attenuated the glomerulosclerosis, inflammatory cytokine release, podocyte apoptosis and renal injury. Collectively, these data indicate that HDAC9 may be involved in the process of DN, especially podocyte injury. Our study suggest that inhibition of HDAC9 may have a therapeutic potential in DN treatment. PMID:27633396

  6. Association of valproate-induced teratogenesis with histone deacetylase inhibition in vivo.

    Science.gov (United States)

    Gurvich, Nadia; Berman, Melissa G; Wittner, Ben S; Gentleman, Robert C; Klein, Peter S; Green, Jeremy B A

    2005-07-01

    Chemically induced birth defects are an important public health and human problem. Here we use Xenopus and zebrafish as models to investigate the mechanism of action of a well-known teratogen, valproic acid (VPA). VPA is a drug used in treatment of epilepsy and bipolar disorder but causes spina bifida if taken during pregnancy. VPA has several biochemical activities, including inhibition of histone deacetylases (HDACs). To investigate the mechanism of action of VPA, we compared its effects in Xenopus and zebrafish embryos with those of known HDAC inhibitors and noninhibitory VPA analogs. We found that VPA and other HDAC inhibitors cause very similar and characteristic developmental defects whereas VPA analogs with poor inhibitory activity in vivo have little teratogenic effect. Unbiased microarray analysis revealed that the effects of VPA and trichostatin A (TSA), a structurally unrelated HDAC inhibitor, are strikingly concordant. The concordance is apparent both by en masse correlation of fold-changes and by detailed similarity of dose-response profiles of individual genes. Together, the results demonstrate that the teratogenic effects of VPA are very likely mediated specifically by inhibition of HDACs.

  7. DBC1 phosphorylation by ATM/ATR inhibits SIRT1 deacetylase in response to DNA damage

    Institute of Scientific and Technical Information of China (English)

    Laura Zannini; Giacomo Buscemi; Ja-Eun Kim; Enrico Fontanella; Domenico Delia

    2012-01-01

    Human DBC1 (deleted in breast cancer-1; KIAA1967) is a nuclear protein that,in response to DNA damage,competitively inhibits the NAD+-dependent deacetylase SIRT1,a regulator of p53 apoptotic functions in response to genotoxic stress.DBC1 depletion in human cells increases SIRT1 activity,resulting in the deacetylation of p53 and protection from apoptosis.However,the mechanisms regulating this process have not yet been determined.Here,we report that,in human cell lines,DNA damage triggered the phosphorylation of DBC1 on Thr454 by ATM (ataxia telangiectasia-mutated) and ATR (ataxia telangiectasia and Rad3-related)kinases.Phosphorylated DBC1 bound to and inhibited SIRT1,resulting in the dissociation of the SIRT1-p53 complex and stimulating p53 acetylation and p53-dependent cell death.Indeed,DBC1-mediated genotoxicity,which was shown in knockdown experiments to be dependent on SIRT1 and p53 expression,was defective in cells expressing the phospho-mutant DBC1T454A.This study describes the first post-translational modification of DBC1 and provides new mechanistic insight linking ATM/ATR to the DBC1-SIRT1-p53 apoptotic axis triggered by DNA damage.

  8. Histone deacetylase inhibition rescues structural and functional brain deficits in a mouse model of Kabuki syndrome

    Science.gov (United States)

    Bjornsson, Hans T.; Benjamin, Joel S.; Zhang, Li; Weissman, Jacqueline; Gerber, Elizabeth E.; Chen, Yi-Chun; Vaurio, Rebecca G.; Potter, Michelle C.; Hansen, Kasper D.; Dietz, Harry C.

    2015-01-01

    Kabuki syndrome is caused by haploinsufficiency for either of two genes that promote the opening of chromatin. If an imbalance between open and closed chromatin is central to the pathogenesis of Kabuki syndrome, agents that promote chromatin opening might have therapeutic potential. We have characterized a mouse model of Kabuki syndrome with a heterozygous deletion in the gene encoding the lysine-specific methyltransferase 2D (Kmt2d), leading to impairment of methyltransferase function. In vitro reporter alleles demonstrated a reduction in histone 4 acetylation and histone 3 lysine 4 trimethylation (H3K4me3) activity in mouse embryonic fibroblasts from Kmt2d+/βGeo mice. These activities were normalized in response to AR-42, a histone deacetylase inhibitor. In vivo, deficiency of H3K4me3 in the dentate gyrus granule cell layer of Kmt2d+/βGeo mice correlated with reduced neurogenesis and hippocampal memory defects. These abnormalities improved upon postnatal treatment with AR-42. Our work suggests that a reversible deficiency in postnatal neurogenesis underlies intellectual disability in Kabuki syndrome. PMID:25273096

  9. New benzothiazole/thiazole-containing hydroxamic acids as potent histone deacetylase inhibitors and antitumor agents.

    Science.gov (United States)

    Tung, Truong Thanh; Oanh, Dao Thi Kim; Dung, Phan Thi Phuong; Hue, Van Thi My; Park, Sang Ho; Han, Byung Woo; Kim, Youngsoo; Hong, Jin-Tae; Han, Sang-Bae; Nam, Nguyen-Hai

    2013-12-01

    Results from clinical studies have demonstrated that inhibitors of histone deacetylase (HDAC) enzymes possess promise for the treatment of several types of cancer. Zolinza(®) (widely known as SAHA) has been approved by the FDA for the treatment of T-cell lymphoma. As a continuity of our ongoing research to find novel small molecules to target these important enzymes, we synthesized a series of benzothiazole-containing analogues of SAHA and found several compounds with very potent anticancer cytotoxicity. In this study, three more compounds of this type, including N(1)-(6-chlorobenzo[d]thiazol-2-yl)-N(8)-hydroxyoctanediamide (3a), N(1)-[6-(trifluoromethyl)benzo[d]thiazol-2-yl]-N(8)-hydroxyoctanediamide (3b) and N(1)-(thiazol-2-yl)-N(8)-hydroxyoctanediamide (6) were synthesized and evaluated for HDAC inhibition and cytotoxic activities. All three compounds showed very potent HDAC inhibitory effects. Docking revealed that both two compounds 3a, 3b showed higher affinities towards HDAC(8) compared to SAHA. In vitro, compound 3a exhibited cytotoxicity equipotent to SAHA against five human cancer cell lines. In term of in vivo activity, compound 3a demonstrated equivalent efficacy to SAHA in mouse xenograft model.

  10. Role of Histone Deacetylase Inhibitors in Relapsed Refractory Multiple Myeloma: A Focus on Vorinostat and Panobinostat.

    Science.gov (United States)

    Afifi, Salma; Michael, Angela; Azimi, Mahshid; Rodriguez, Mabel; Lendvai, Nikoletta; Landgren, Ola

    2015-12-01

    Multiple myeloma is a neoplastic plasma cell disorder that is characterized by clonal proliferation of plasma cells in the bone marrow, monoclonal protein in the blood and/or urine, and associated organ dysfunction and biomarkers. There have been multiple recent advances in the relapsed and refractory setting. Major steps forward include the introduction of proteasome inhibitors (bortezomib and carfilzomib) and immunomodulatory drugs (thalidomide, lenalidomide, and pomalidomide) in various combinations. These drugs have changed the management of multiple myeloma and have extended overall survival in the past decade. Established curative therapy is not yet available for patients diagnosed with multiple myeloma, supporting the development of new treatment targets. Histone deacetylase inhibitors have multiple proposed mechanisms of action in the treatment of multiple myeloma. Both vorinostat and panobinostat have demonstrated some activity against multiple myeloma, and due to the benefits reported with panobinostat, the U.S. Food and Drug Administration has recently approved the drug for the treatment of relapsed and refractory multiple myeloma. In this article, we describe the pharmacology, efficacy, and toxicity profile of vorinostat and panobinostat and their possible place in therapy.

  11. Histone deacetylase inhibitors mediate DNA damage repair in ameliorating hemorrhagic cystitis

    Science.gov (United States)

    Haldar, Subhash; Dru, Christopher; Mishra, Rajeev; Tripathi, Manisha; Duong, Frank; Angara, Bryan; Fernandez, Ana; Arditi, Moshe; Bhowmick, Neil A.

    2016-01-01

    Hemorrhagic cystitis is an inflammatory and ulcerative bladder condition associated with systemic chemotherapeutics, like cyclophosphomide. Earlier, we reported reactive oxygen species resulting from cyclophosphamide metabolite, acrolein, causes global methylation followed by silencing of DNA damage repair genes. Ogg1 (8-oxoguanine DNA glycosylase) is one such silenced base excision repair enzyme that can restore DNA integrity. The accumulation of DNA damage results in subsequent inflammation associated with pyroptotic death of bladder smooth muscle cells. We hypothesized that reversing inflammasome-induced imprinting in the bladder smooth muscle could prevent the inflammatory phenotype. Elevated recruitment of Dnmt1 and Dnmt3b to the Ogg1 promoter in acrolein treated bladder muscle cells was validated by the pattern of CpG methylation revealed by bisulfite sequencing. Knockout of Ogg1 in detrusor cells resulted in accumulation of reactive oxygen mediated 8-Oxo-dG and spontaneous pyroptotic signaling. Histone deacetylase (HDAC) inhibitor, suberoylanilide hydroxamic acid (SAHA), restored Ogg1 expression in cells treated with acrolein and mice treated with cyclophosphamide superior to the standard of care, mesna or nicotinamide-induced DNA demethylation. SAHA restored cyclophosphamide-induced bladder pathology to that of untreated control mice. The observed epigenetic imprinting induced by inflammation suggests a new therapeutic target for the treatment of hemorrhagic cystitis. PMID:27995963

  12. Anti-Inflammatory Effects of Spirulina platensis Extract via the Modulation of Histone Deacetylases.

    Science.gov (United States)

    Pham, Tho X; Park, Young-Ki; Lee, Ji-Young

    2016-06-21

    We previously demonstrated that the organic extract of Spirulina platensis (SPE), an edible blue-green alga, possesses potent anti-inflammatory effects. In this study, we investigated if the regulation of histone deacetylases (HDACs) play a role in the anti-inflammatory effect of SPE in macrophages. Treatment of macrophages with SPE rapidly and dose-dependently reduced HDAC2, 3, and 4 proteins which preceded decreases in their mRNA levels. Degradation of HDAC4 protein was attenuated in the presence of inhibitors of calpain proteases, lysosomal acidification, and Ca(2+)/calmodulin-dependent protein kinase II, respectively, but not a proteasome inhibitor. Acetylated histone H3 was increased in SPE-treated macrophages to a similar level as macrophages treated with a pan-HDAC inhibitor, with concomitant inhibition of inflammatory gene expression upon LPS stimulation. Knockdown of HDAC3 increased basal and LPS-induced pro-inflammatory gene expression, while HDAC4 knockdown increased basal expression of interleukin-1β (IL-1β), but attenuated LPS-induced inflammatory gene expression. Chromatin immunoprecipitation showed that SPE decreased p65 binding and H3K9/K14 acetylation at the Il-1β and tumor necrosis factor α (Tnfα) promoters. Our results suggest that SPE increased global histone H3 acetylation by facilitating HDAC protein degradation, but decreases histone H3K9/K14 acetylation and p65 binding at the promoters of Il-1β and Tnfα to exert its anti-inflammatory effect.

  13. Tetraspanin CD9 modulates human lymphoma cellular proliferation via histone deacetylase activity

    Energy Technology Data Exchange (ETDEWEB)

    Herr, Michael J. [Vascular Biology Center of Excellence, The University of Tennessee Health Science Center, Memphis, TN 38163 (United States); Department of Medicine, The University of Tennessee Health Science Center, Memphis, TN 38163 (United States); Department of Molecular Sciences, The University of Tennessee Health Science Center, Memphis, TN 38163 (United States); Department of Surgery, The University of Tennessee Health Science Center, Memphis, TN 38163 (United States); Longhurst, Celia M.; Baker, Benjamin [Vascular Biology Center of Excellence, The University of Tennessee Health Science Center, Memphis, TN 38163 (United States); Homayouni, Ramin [Department of Biology, Bioinformatics Program, University of Memphis, Memphis, TN 38152 (United States); Speich, Henry E.; Kotha, Jayaprakash [Vascular Biology Center of Excellence, The University of Tennessee Health Science Center, Memphis, TN 38163 (United States); Jennings, Lisa K., E-mail: ljennings@uthsc.edu [Vascular Biology Center of Excellence, The University of Tennessee Health Science Center, Memphis, TN 38163 (United States); Department of Medicine, The University of Tennessee Health Science Center, Memphis, TN 38163 (United States); Department of Molecular Sciences, The University of Tennessee Health Science Center, Memphis, TN 38163 (United States); Department of Surgery, The University of Tennessee Health Science Center, Memphis, TN 38163 (United States); Department of Biology, Bioinformatics Program, University of Memphis, Memphis, TN 38152 (United States)

    2014-05-16

    Highlights: • CD9 is differentially expressed in human Burkitt’s lymphoma cells. • We found that CD9 expression promotes these cells proliferation. • CD9 expression also increases HDAC activity. • HDAC inhibition decreased both cell proliferation and importantly CD9 expression. • CD9 may dictate HDAC efficacy and play a role in HDAC regulation. - Abstract: Non-Hodgkin Lymphoma (NHL) is a type of hematological malignancy that affects two percent of the overall population in the United States. Tetraspanin CD9 is a cell surface protein that has been thoroughly demonstrated to be a molecular facilitator of cellular phenotype. CD9 expression varies in two human lymphoma cell lines, Raji and BJAB. In this report, we investigated the functional relationship between CD9 and cell proliferation regulated by histone deacetylase (HDAC) activity in these two cell lines. Introduction of CD9 expression in Raji cells resulted in significantly increased cell proliferation and HDAC activity compared to Mock transfected Raji cells. The increase in CD9–Raji cell proliferation was significantly inhibited by HDAC inhibitor (HDACi) treatment. Pretreatment of BJAB cells with HDAC inhibitors resulted in a significant decrease in endogenous CD9 mRNA and cell surface expression. BJAB cells also displayed decreased cell proliferation after HDACi treatment. These results suggest a significant relationship between CD9 expression and cell proliferation in human lymphoma cells that may be modulated by HDAC activity.

  14. Histone deacetylase inhibitors: Future therapeutics for insulin resistance and type 2 diabetes.

    Science.gov (United States)

    Sharma, Sorabh; Taliyan, Rajeev

    2016-11-01

    Insulin resistance is a common feature of obesity and predisposes the affected individuals to a variety of pathologies, including type 2 diabetes mellitus (T2DM), dyslipidemias, hypertension, cardiovascular disease etc. Insulin resistance is the primary cause of T2DM and it occurs many years before the disease onset. Although Thiazolidinediones (TZDs) such as rosiglitazone and pioglitazone are outstanding insulin sensitizers and are in clinical use since 1990s, however, their serious side effects such as heart attack and bladder cancer have limited their utilization. Thus, there is an unmet need to identify a new class of drugs with insulin sensitizing activity and minimal side effects. In the recent years, Histone deacetylase (HDAC) has emerged as a new molecular target in the control of insulin resistance and T2DM. The level of histone acetylation/deacetylation has been found to be altered during insulin resistance and T2DM conditions. HDAC inhibitors have been found to effectively manage insulin resistance and T2DM in various preclinical models and clinical trials. In this review we will focus on various aspects related to regulation of insulin signalling by HDACs and the future scope of HDAC inhibitors as therapeutics for insulin resistance.

  15. Histone deacetylases: a common molecular target for differentiation treatment of acute myeloid leukemias?

    Science.gov (United States)

    Minucci, S; Nervi, C; Lo Coco, F; Pelicci, P G

    2001-05-28

    Recent discoveries have identified key molecular events in the pathogenesis of acute promyelocytic leukemia (APL), caused by chromosomal rearrangements of the transcription factor RAR (resulting in a fusion protein with the product of other cellular genes, such as PML). Oligomerization of RAR, through a self-association domain present in PML, imposes an altered interaction with transcriptional co-regulators (NCoR/SMRT). NCoR/SMRT are responsible for recruitment of histone deacetylases (HDACs), which is required for transcriptional repression of PML-RAR target genes, and for the transforming potential of the fusion protein. Oligomerization and altered recruitment of HDACs are also responsible for transformation by the fusion protein AML1-ETO, extending these mechanisms to other forms of acute myeloid leukemias (AMLs) and suggesting that HDAC is a common target for myeloid leukemias. Strikingly, AML1-ETO expression blocks retinoic acid (RA) signaling in hematopoietic cells, suggesting that interference with the RA pathway (genetically altered in APL) by HDAC recruitment may be a common theme in AMLs. Treatment of APLs with RA, and of other AMLs with RA plus HDAC inhibitors (HDACi), results in myeloid differentiation. Thus, activation of the RA signaling pathway and inhibition of HDAC activity might represent a general strategy for the differentiation treatment of myeloid leukemias.

  16. Molecular modeling study on tunnel behavior in different histone deacetylase isoforms.

    Directory of Open Access Journals (Sweden)

    Sundarapandian Thangapandian

    Full Text Available Histone deacetylases (HDACs have emerged as effective therapeutic targets in the treatment of various diseases including cancers as these enzymes directly involved in the epigenetic regulation of genes. However the development of isoform-selective HDAC inhibitors has been a challenge till date since all HDAC enzymes possess conserved tunnel-like active site. In this study, using molecular dynamics simulation we have analyzed the behavior of tunnels present in HDAC8, 10, and 11 enzymes of class I, II, and IV, respectively. We have identified the equivalent tunnel forming amino acids in these three isoforms and found that they are very much conserved with subtle differences to be utilized in selective inhibitor development. One amino acid, methionine of HDAC8, among six tunnel forming residues is different in isoforms of other classes (glutamic acid (E in HDAC10 and leucine (L in HDAC 11 based on which mutations were introduced in HDAC11, the less studied HDAC isoform, to observe the effects of this change. The HDAC8-like (L268M mutation in the tunnel forming residues has almost maintained the deep and narrow tunnel as present in HDAC8 whereas HDAC10-like (L268E mutation has changed the tunnel wider and shallow as observed in HDAC10. These results explained the importance of the single change in the tunnel formation in different isoforms. The observations from this study can be utilized in the development of isoform-selective HDAC inhibitors.

  17. Histone deacetylase 3 depletion in osteo/chondroprogenitor cells decreases bone density and increases marrow fat.

    Directory of Open Access Journals (Sweden)

    David F Razidlo

    Full Text Available Histone deacetylase (Hdac3 is a nuclear enzyme that contributes to epigenetic programming and is required for embryonic development. To determine the role of Hdac3 in bone formation, we crossed mice harboring loxP sites around exon 7 of Hdac3 with mice expressing Cre recombinase under the control of the osterix promoter. The resulting Hdac3 conditional knockout (CKO mice were runted and had severe deficits in intramembranous and endochondral bone formation. Calvarial bones were significantly thinner and trabecular bone volume in the distal femur was decreased 75% in the Hdac3 CKO mice due to a substantial reduction in trabecular number. Hdac3-CKO mice had fewer osteoblasts and more bone marrow adipocytes as a proportion of tissue area than their wildtype or heterozygous littermates. Bone formation rates were depressed in both the cortical and trabecular regions of Hdac3 CKO femurs. Microarray analyses revealed that numerous developmental signaling pathways were affected by Hdac3-deficiency. Thus, Hdac3 depletion in osterix-expressing progenitor cells interferes with bone formation and promotes bone marrow adipocyte differentiation. These results demonstrate that Hdac3 inhibition is detrimental to skeletal health.

  18. Histone deacetylase inhibitors mediate DNA damage repair in ameliorating hemorrhagic cystitis.

    Science.gov (United States)

    Haldar, Subhash; Dru, Christopher; Mishra, Rajeev; Tripathi, Manisha; Duong, Frank; Angara, Bryan; Fernandez, Ana; Arditi, Moshe; Bhowmick, Neil A

    2016-12-20

    Hemorrhagic cystitis is an inflammatory and ulcerative bladder condition associated with systemic chemotherapeutics, like cyclophosphomide. Earlier, we reported reactive oxygen species resulting from cyclophosphamide metabolite, acrolein, causes global methylation followed by silencing of DNA damage repair genes. Ogg1 (8-oxoguanine DNA glycosylase) is one such silenced base excision repair enzyme that can restore DNA integrity. The accumulation of DNA damage results in subsequent inflammation associated with pyroptotic death of bladder smooth muscle cells. We hypothesized that reversing inflammasome-induced imprinting in the bladder smooth muscle could prevent the inflammatory phenotype. Elevated recruitment of Dnmt1 and Dnmt3b to the Ogg1 promoter in acrolein treated bladder muscle cells was validated by the pattern of CpG methylation revealed by bisulfite sequencing. Knockout of Ogg1 in detrusor cells resulted in accumulation of reactive oxygen mediated 8-Oxo-dG and spontaneous pyroptotic signaling. Histone deacetylase (HDAC) inhibitor, suberoylanilide hydroxamic acid (SAHA), restored Ogg1 expression in cells treated with acrolein and mice treated with cyclophosphamide superior to the standard of care, mesna or nicotinamide-induced DNA demethylation. SAHA restored cyclophosphamide-induced bladder pathology to that of untreated control mice. The observed epigenetic imprinting induced by inflammation suggests a new therapeutic target for the treatment of hemorrhagic cystitis.

  19. Histone deacetylases and their inhibitors: molecular mechanisms and therapeutic implications in diabetes mellitus

    Directory of Open Access Journals (Sweden)

    Xiaojie Wang

    2012-08-01

    Full Text Available Epigenetic mechanisms such as DNA methylation, histone modification and microRNA changes have been shown to be important for the regulation of cellular functions. Among them, histone deacetylases (HDACs are enzymes that balance the acetylation activities of histone acetyltransferases in chromatin remodeling and play essential roles in gene transcription to regulate cell proliferation, migration and death. Recent studies indicate that HDACs are promising drug targets for a wide range of diseases including cancer, neurodegenerative and psychiatric disorders, cardiovascular dysfunction, autoimmunity and diabetes mellitus. This review highlights the role of HDACs in diabetes mellitus and outlines several important cellular and molecular mechanisms by which HDACs regulate glucose homeostasis and can be targeted for the treatment of diabetic microvascular complications. It is hoped that our understanding of the role of HDACs in diabetes mellitus will lead to the development of better diagnostic tools and the design of more potent and specific drugs targeting selective HDAC proteins for the treatment of the disease.

  20. Inhibition of histone deacetylase in utero causes sociability deficits in postnatal mice.

    Science.gov (United States)

    Moldrich, Randal X; Leanage, Gayeshika; She, David; Dolan-Evans, Elliot; Nelson, Michael; Reza, Nargis; Reutens, David C

    2013-11-15

    Exposure to sodium valproate (VPA) in utero increases the risk of language impairment and a diagnosis of autism spectrum disorder (ASD). Mice exposed to VPA while in utero have also shown postnatal social deficits. Inhibition of histone deacetylase (HDAC) is one of VPA's many biological effects. The main objective of this study was to test the hypothesis that HDAC inhibition causes these behavioral outcomes following prenatal VPA exposure in mice. We exposed embryonic mice to VPA, the HDAC inhibitor trichostatin A (TSA), or vehicle controls. TSA (1mg/kg) inhibited HDAC in embryonic tissue at a level comparable to 600 mg/kg VPA, resulting in significant increases in histone H3 and H4 acetylation, and histone H3 lysine 4 tri-methylation. Postnatally, decreases in ultrasonic vocalization, olfactory motivation and sociability were observed in TSA and VPA-exposed pups. Treated mice exhibited elevated digging and grooming suggestive of mild restrictive and repetitive behaviors. Olfactory social preference, social novelty and habituation were normal. Together, these data indicate that embryonic HDAC inhibition alone can cause abnormal social behaviors in mice. This result serves as a molecular understanding of infant outcomes following mild VPA exposure in utero.