WorldWideScience

Sample records for chitinous cuticle form

  1. 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.

  2. 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

  3. 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

  4. Analysis of expression and chitin-binding activity of the wing disc cuticle protein BmWCP4 in the silkworm, Bombyx mori.

    Science.gov (United States)

    Deng, Hui-Min; Li, Yong; Zhang, Jia-Ling; Liu, Lin; Feng, Qi-Li

    2016-12-01

    The insect exoskeleton is mainly composed of chitin filaments linked by cuticle proteins. When insects molt, the cuticle of the exoskeleton is renewed by degrading the old chitin and cuticle proteins and synthesizing new ones. In this study, chitin-binding activity of the wing disc cuticle protein BmWCP4 in Bombyx mori was studied. Sequence analysis showed that the protein had a conservative hydrophilic "R&R" chitin-binding domain (CBD). Western blotting showed that BmWCP4 was predominately expressed in the wing disc-containing epidermis during the late wandering and early pupal stages. The immunohistochemistry result showed that the BmWCP4 was mainly present in the wing disc tissues containing wing bud and trachea blast during day 2 of wandering stage. Recombinant full-length BmWCP4 protein, "R&R" CBD peptide (CBD), non-CBD peptide (BmWCP4-CBD - ), four single site-directed mutated peptides (M 1 , M 2 , M 3 and M 4 ) and four-sites-mutated peptide (M F ) were generated and purified, respectively, for in vitro chitin-binding assay. The results indicated that both the full-length protein and the "R&R" CBD peptide could bind with chitin, whereas the BmWCP4-CBD - could not bind with chitin. The single residue mutants M 1 , M 2 , M 3 and M 4 reduced but did not completely abolish the chitin-binding activity, while four-sites-mutated protein M F completely lost the chitin-binding activity. These data indicate that BmWCP4 protein plays a critical role by binding to the chitin filaments in the wing during larva-to-pupa transformation. The conserved aromatic amino acids are critical in the interaction between chitin and the cuticle protein. © 2015 Institute of Zoology, Chinese Academy of Sciences.

  5. Chitin Degradation Proteins Produced by the Marine Bacterium Vibrio harveyi Growing on Different Forms of Chitin.

    Science.gov (United States)

    Svitil, A L; Chadhain, S; Moore, J A; Kirchman, D L

    1997-02-01

    Relatively little is known about the number, diversity, and function of chitinases produced by bacteria, even though chitin is one of the most abundant polymers in nature. Because of the importance of chitin, especially in marine environments, we examined chitin-degrading proteins in the marine bacterium Vibrio harveyi. This bacterium had a higher growth rate and more chitinase activity when grown on (beta)-chitin (isolated from squid pen) than on (alpha)-chitin (isolated from snow crab), probably because of the more open structure of (beta)-chitin. When exposed to different types of chitin, V. harveyi excreted several chitin-degrading proteins into the culture media. Some chitinases were present with all of the tested chitins, while others were unique to a particular chitin. We cloned and identified six separate chitinase genes from V. harveyi. These chitinases appear to be unique based on DNA restriction patterns, immunological data, and enzyme activity. This marine bacterium and probably others appear to synthesize separate chitinases for efficient utilization of different forms of chitin and chitin by-products.

  6. Timed Knickkopf function is essential for wing cuticle formation in Drosophila melanogaster.

    Science.gov (United States)

    Li, Kaixia; Zhang, Xubo; Zuo, Ying; Liu, Weimin; Zhang, Jianzhen; Moussian, Bernard

    2017-10-01

    The insect cuticle is an extracellular matrix that consists of the polysaccharide chitin, proteins, lipids and organic molecules that are arranged in distinct horizontal layers. In Drosophila melanogaster, these layers are not formed sequentially, but, at least partially, at the same time. Timing of the underlying molecular mechanisms is conceivably crucial for cuticle formation. To study this issue, we determined the time period during which the function of Knickkopf (Knk), a key factor of chitin organization, is required for wing cuticle differentiation in D. melanogaster. Although knk is expressed throughout metamorphosis, we demonstrate that its expression 30 h prior and 48 h after pupariation is essential for correct wing cuticle formation. In other words, expression beyond this period is futile. Importantly, manipulation of Knk expression during this time causes wing bending suggesting an effect of Knk amounts on the physical properties of the wing cuticle. Manipulation of Knk expression also interferes with the structure and function of the cuticle surface. First, we show that the shape of surface nano-structures depends on the expression levels of knk. Second, we find that cuticle impermeability is compromised in wings with reduced knk expression. In summary, despite the extended supply of Knk during metamorphosis, controlled amounts of Knk are important for correct wing cuticle differentiation and function in a concise period of time. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. The Gene Expression Program for the Formation of Wing Cuticle in Drosophila.

    Directory of Open Access Journals (Sweden)

    Lukasz F Sobala

    2016-05-01

    Full Text Available The cuticular exoskeleton of insects and other arthropods is a remarkably versatile material with a complex multilayer structure. We made use of the ability to isolate cuticle synthesizing cells in relatively pure form by dissecting pupal wings and we used RNAseq to identify genes expressed during the formation of the adult wing cuticle. We observed dramatic changes in gene expression during cuticle deposition, and combined with transmission electron microscopy, we were able to identify candidate genes for the deposition of the different cuticular layers. Among genes of interest that dramatically change their expression during the cuticle deposition program are ones that encode cuticle proteins, ZP domain proteins, cuticle modifying proteins and transcription factors, as well as genes of unknown function. A striking finding is that mutations in a number of genes that are expressed almost exclusively during the deposition of the envelope (the thin outermost layer that is deposited first result in gross defects in the procuticle (the thick chitinous layer that is deposited last. An attractive hypothesis to explain this is that the deposition of the different cuticle layers is not independent with the envelope instructing the formation of later layers. Alternatively, some of the genes expressed during the deposition of the envelope could form a platform that is essential for the deposition of all cuticle layers.

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

    Science.gov (United States)

    Oh, Dongyeop X; Shin, Sara; Lim, Chanoong; Hwang, Dong Soo

    2013-09-06

    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.

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

    Directory of Open Access Journals (Sweden)

    Dongyeop X. Oh

    2013-09-01

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

  10. 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

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

    Science.gov (United States)

    Butzloff, Peter R.

    2011-01-01

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

  12. 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

  13. Design and mechanical properties of insect cuticle.

    Science.gov (United States)

    Vincent, Julian F V; Wegst, Ulrike G K

    2004-07-01

    Since nearly all adult insects fly, the cuticle has to provide a very efficient and lightweight skeleton. Information is available about the mechanical properties of cuticle-Young's modulus of resilin is about 1 MPa, of soft cuticles about 1 kPa to 50 MPa, of sclerotised cuticles 1-20 GPa; Vicker's Hardness of sclerotised cuticle ranges between 25 and 80 kgf mm(-2); density is 1-1.3 kg m(-3)-and one of its components, chitin nanofibres, the Young's modulus of which is more than 150 GPa. Experiments based on fracture mechanics have not been performed although the layered structure probably provides some toughening. The structural performance of wings and legs has been measured, but our understanding of the importance of buckling is lacking: it can stiffen the structure (by elastic postbuckling in wings, for example) or be a failure mode. We know nothing of fatigue properties (yet, for instance, the insect wing must undergo millions of cycles, flexing or buckling on each cycle). The remarkable mechanical performance and efficiency of cuticle can be analysed and compared with those of other materials using material property charts and material indices. Presented in this paper are four: Young's modulus-density (stiffness per unit weight), specific Young's modulus-specific strength (elastic hinges, elastic energy storage per unit weight), toughness-Young's modulus (fracture resistance under various loading conditions), and hardness (wear resistance). In conjunction with a structural analysis of cuticle these charts help to understand the relevance of microstructure (fibre orientation effects in tendons, joints and sense organs, for example) and shape (including surface structure) of this fibrous composite for a given function. With modern techniques for analysis of structure and material, and emphasis on nanocomposites and self-assembly, insect cuticle should be the archetype for composites at all levels of scale.

  14. cuticleDB: a relational database of Arthropod cuticular proteins

    Directory of Open Access Journals (Sweden)

    Willis Judith H

    2004-09-01

    Full Text Available Abstract Background The insect exoskeleton or cuticle is a bi-partite composite of proteins and chitin that provides protective, skeletal and structural functions. Little information is available about the molecular structure of this important complex that exhibits a helicoidal architecture. Scores of sequences of cuticular proteins have been obtained from direct protein sequencing, from cDNAs, and from genomic analyses. Most of these cuticular protein sequences contain motifs found only in arthropod proteins. Description cuticleDB is a relational database containing all structural proteins of Arthropod cuticle identified to date. Many come from direct sequencing of proteins isolated from cuticle and from sequences from cDNAs that share common features with these authentic cuticular proteins. It also includes proteins from the Drosophila melanogaster and the Anopheles gambiae genomes, that have been predicted to be cuticular proteins, based on a Pfam motif (PF00379 responsible for chitin binding in Arthropod cuticle. The total number of the database entries is 445: 370 derive from insects, 60 from Crustacea and 15 from Chelicerata. The database can be accessed from our web server at http://bioinformatics.biol.uoa.gr/cuticleDB. Conclusions CuticleDB was primarily designed to contain correct and full annotation of cuticular protein data. The database will be of help to future genome annotators. Users will be able to test hypotheses for the existence of known and also of yet unknown motifs in cuticular proteins. An analysis of motifs may contribute to understanding how proteins contribute to the physical properties of cuticle as well as to the precise nature of their interaction with chitin.

  15. Chitin deacetylase

    International Nuclear Information System (INIS)

    Ito, E.; Araki, Y.

    1988-01-01

    This paper discusses chitosan which is a unique polysaccharide in that it possesses free amino groups. The authors state that most of the amino sugar residing in naturally occurring polysaccharides is believed to be N-acylated. An enzyme catalyzing the conversion of chitin to chitosan was first demonstrated in an extract of Mucor rouxii. A similar enzyme was found in the culture filtrate of a plant pathogen, Colletotrichum lindemuthianum. They present the chitin deacetylase activity assayed by measuring the radioactivity of [ 3 H] acetic acid liberated from a water-soluble chitin derivative, glycol [acetyl- 3 H] chitin

  16. 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. PMID:24015298

  17. The architecture of the joint head cuticle and its transition to the arthrodial membrane in the terrestrial crustacean Porcellio scaber.

    Science.gov (United States)

    Ruangchai, Sukhum; Reisecker, Christian; Hild, Sabine; Ziegler, Andreas

    2013-04-01

    The cuticle of terrestrial isopods is an interesting model for the study of structure-function relationships in biological composite materials. Its organic matrix has a hierarchically organised structure, and type and phase of the mineral compound can vary. The cuticle forms functionally diverse skeletal elements whose properties are adapted to their specific functions. In order to better understand the relation between structure, composition and function of isopod cuticle, we studied the structure and composition of the joint head that is part of the pereiopod's basis. It consists of a central region, whose shape fits well into the joint socket, and an edge region that is connected to the soft arthrodial membrane and protects the central region from mechanical load. The cuticle architecture of the joint head has local variations in structure and composition. In the central region the cuticle is similar to the previously published tergite cuticle. High concentrations of amorphous calcium phosphate are located in the endocuticle suggesting a coexistence with amorphous calcium carbonate. The edge region has an unexpected organisation characterised by thickening of the epi- and exocuticle and an unusual unidirectional orientation of chitin-protein fibrils within the endocuticle. The concentrations of phosphate are considerably higher than in the central region. The overall differentiation in the cuticular architecture of the edge in comparison to the central region reflects the adaptation to mechanical strains the cuticle has to sustain during contraction of extensor muscles, and to the structural and compositional transition from the edge to the connecting arthrodial membrane. Copyright © 2013 Elsevier Inc. All rights reserved.

  18. Air pollutants and the leaf cuticle. Proceedings

    International Nuclear Information System (INIS)

    Percy, K.E.; Jagels, R.; Simpson, C.J.

    1994-01-01

    The leaf surface forms the interface between plants and a deteriorating atmospheric environment. It is, therefore, the first point of contact between plants and air pollutants and presents an effective barrier to pollutant entry. Outermost surfaces of leaves are covered by a thin, lipoidal, non-living membrane called a cuticle. Cuticle integrity is essential to plant survival and has many essential functions, including the prevention of excessive water loss, regulation of solute uptake and protection of sensitive underlying photosynthetic tissues against harmful irradiation such as enhanced UV-B resulting from stratospheric ozone depletion. The physicochemical properties of the cuticle vary greatly between and within species. They are known to be sensitive to change through natural and anthropogenic influences. This book comprises contributions made to a NATO-sponsored Advanced Research Workshop ''Air Pollutants and the Leaf Cuticle'' held October 4-9, 1993 in Fredericton, New Brunswick, Canada. The objective of the ARW was to bring together for the first time international expertise on the subject of air pollutant interactions with the cuticle. In order to facilitate a state-of-science review, the ARW was structured around four themes. They were as follows: 1. Cuticular physicochemical characteristics, physiological, regulatory, and protective roles. 2. Effects, mechanisms, and consequences of air pollutant interaction with leaf cuticles. 3. Non-anthropogenic and environmental influences on the cuticle and potential of the cuticle for biomonitoring and critical levels mapping. 4. New developments in experimental methodology and analytical techniques. (orig./vhe)

  19. Helicoidal microstructure of Scarabaei cuticle and biomimetic research

    International Nuclear Information System (INIS)

    Chen, B.; Peng, X.; Cai, C.; Niu, H.; Wu, X.

    2006-01-01

    Insect cuticles as a natural biocomposite include many favorable microstructures which have been refined over centuries and endow the cuticles excellent mechanical and physical properties, such as light weight, high strength and toughness, etc. The various microstructures of a Scarabaei cuticle are investigated with a scanning electronic microscope and reported in this paper. It is found that the cuticle is a kind of fiber-reinforced biocomposite composed of chitin-fiber layers and sclerous protein matrixes. Different chitin-fiber layers have different orientations, composed of crossed and helicoidal structures at different location. In the helicoidal structure, each fiber layer rotates with an almost fixed angle against its neighboring layer. The maximum pullout energy of the helicoidal structure is analyzed based on the representative model of the structure. The result shows that the pullout energy of the helicoidal structure is markedly larger than that of the conventional 0 o -structure. A biomimetic composite with the observed helicoidal structure is designed and fabricated. A comparative test shows that the fracture toughness of the biomimetic composite is markedly larger than that of the 0 o -layer composite

  20. Apple cuticle: the perfect interface

    Science.gov (United States)

    Curry, Eric; Arey, Bruce

    2010-06-01

    The domestic apple might well be called an 'extreme' fruit. In the arid Northwest United States, the fruit often tolerates surface temperatures ranging from -2 °C in the early spring to 50 °C in the heat of summer, and again to -2 °C during controlled postharvest storage for up to 12 months. During its 18-month existence, the apple maintains a cuticle that is dynamic and environmentally responsive to protect against 1) cellular water loss during desiccation stress and 2) excessive uptake of standing surface moisture. Physiological disorders of the peel such as russeting, cracking, splitting, flecking and lenticel marking, develop as epidermal cells respond to rapid changes in ambient conditions at specific developmental stages during the growing season. Resultant market losses underlie research investigating the nature of apple cuticle growth and development. Ultrastructural analysis of the pro-cuticle using scanning electron microscopy indicates an overlapping network of lipid-based distally-elongating microtubules--produced by and connected to epidermal cells--which co-polymerize to form an organic solvent-insoluble semi-permeable cutin matrix. Microtubule elongation, aggregation, and polymerization function together as long as the fruit continues to enlarge. The nature of lipid transport from the epidermal cells through the cell wall to become part of the cuticular matrix was explored using an FEI Helios NanoLabTM DualBeamTM focused ion beam/scanning electron microscope on chemically- and cryo-fixed peel tissue from mature or freshly harvested apples. Based on microtubule dimensions, regular projections found at the cell/cuticle interface suggest an array of microtubule-like structures associated with the epidermal cell.

  1. 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%.

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

    Science.gov (United States)

    Kaya, Murat; Lelešius, Evaldas; Nagrockaitė, Radvilė; Sargin, Idris; Arslan, Gulsin; Mol, Abbas; Baran, Talat; Can, Esra; Bitim, Betul

    2015-01-01

    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%.

  3. Structural analysis of group II chitinase (ChtII) catalysis completes the puzzle of chitin hydrolysis in insects.

    Science.gov (United States)

    Chen, Wei; Qu, Mingbo; Zhou, Yong; Yang, Qing

    2018-02-23

    Chitin is a linear homopolymer of N -acetyl-β-d-glucosamines and a major structural component of insect cuticles. Chitin hydrolysis involves glycoside hydrolase family 18 (GH18) chitinases. In insects, chitin hydrolysis is essential for periodic shedding of the old cuticle ecdysis and proceeds via a pathway different from that in the well studied bacterial chitinolytic system. Group II chitinase (ChtII) is a widespread chitinolytic enzyme in insects and contains the greatest number of catalytic domains and chitin-binding domains among chitinases. In Lepidopterans, ChtII and two other chitinases, ChtI and Chi-h, are essential for chitin hydrolysis. Although ChtI and Chi-h have been well studied, the role of ChtII remains elusive. Here, we investigated the structure and enzymology of Of ChtII, a ChtII derived from the insect pest Ostrinia furnacalis We present the crystal structures of two catalytically active domains of Of ChtII, Of ChtII-C1 and Of ChtII-C2, both in unliganded form and complexed with chitooligosaccharide substrates. We found that Of ChtII-C1 and Of ChtII-C2 both possess long, deep substrate-binding clefts with endochitinase activities. Of ChtII exhibited structural characteristics within the substrate-binding cleft similar to those in Of Chi-h and Of ChtI. However, Of ChtII lacked structural elements favoring substrate binding beyond the active sites, including an extra wall structure present in Of Chi-h. Nevertheless, the numerous domains in Of ChtII may compensate for this difference; a truncation containing one catalytic domain and three chitin-binding modules ( Of ChtII-B4C1) displayed activity toward insoluble polymeric substrates that was higher than those of Of Chi-h and Of ChtI. Our observations provide the last piece of the puzzle of chitin hydrolysis in insects. © 2018 by The American Society for Biochemistry and Molecular Biology, Inc.

  4. Chlorinated tyrosine derivatives in insect cuticle

    DEFF Research Database (Denmark)

    Andersen, Svend Olav

    2004-01-01

    A method for quantitative measurement of 3-monochlorotyrosine and 3,5-dichlorotyrosine in insect cuticles is described, and it is used for determination of their distribution in various cuticular regions in nymphs and adults of the desert locust, Schistocerca gregaria. The two chlorinated tyrosine......, not-yet sclerotized cuticle of adult femur and tibia, the amounts increased rapidly during the first 24 h after ecdysis and more slowly during the next two weeks. Control analyses using stable isotope dilution mass spectrometry have confirmed that the chlorinated tyrosines are not artifacts formed...

  5. Modification of chitin as substrates for chitinase

    African Journals Online (AJOL)

    sunny t

    2015-05-06

    May 6, 2015 ... Enzymes are able to bind to their substrates specifically at the active site. The proximity and ... the presence of chitin as a carbon source (Chernin et al.,. 1998). ... Possible rearrangement of chitin structure ... and form larger granules. .... Medium for Enumeration of Actinomycetes in Water and Soil. Appl.

  6. Kinetic study of solid phase demineralization by weak acids in one-step enzymatic bio-refinery of shrimp cuticles

    OpenAIRE

    Baron, Regis; Socol, Marius; Arhaliass, A.; Bruzac, Sandrine; Le Roux, Karine; Del Pino, J. Rodriguez; Berge, Jean-pascal; Kaas, Raymond

    2015-01-01

    We describe a one-step bio-refinery process for shrimp composites by-products. Its originality lies in a simple rapid (6 h) biotechnological cuticle fragmentation process that recovers all major compounds (chitins, peptides and minerals in particular calcium). The process consists of a controlled exogenous enzymatic proteolysis in a food-grade acidic medium allowing chitin purification (solid phase), and recovery of peptides and minerals (liquid phase). At a pH of between 3.5 and 4, protease ...

  7. Concurrent protein synthesis is required for in vivo chitin synthesis in postmolt blue crabs

    International Nuclear Information System (INIS)

    Horst, M.N.

    1990-01-01

    Chitin synthesis in crustaceans involves the deposition of a protein-polysaccharide complex at the apical surface of epithelial cells which secrete the cuticle or exoskeleton. The present study involves an examination of in vivo incorporation of radiolabeled amino acids and amino sugars into the cuticle of postmolt blue crabs, Callinectes sapidus. Rates of incorporation of both 3H leucine and 3H threonine were linear with respect to time of incubation. Incorporation of 3H threonine into the endocuticle was inhibited greater than 90% in the presence of the protein synthesis inhibitor, puromycin. Linear incorporation of 14C glucosamine into the cuticle was also demonstrated; a significant improvement of radiolabeling was achieved by using 14C-N-acetylglucosamine as the labeled precursor. Incorporation of 3H-N-acetylglucosamine into the cuticle of postmolt blue crabs was inhibited 89% by puromycin, indicating that concurrent protein synthesis is required for the deposition of chitin in the blue crab. Autoradiographic analysis of control vs. puromycin-treated crabs indicates that puromycin totally blocks labeling of the new endocuticle with 3H glucosamine. These results are consistent with the notion that crustacean chitin is synthesized as a protein-polysaccharide complex. Analysis of the postmolt and intermolt blue crab cuticle indicates that the exoskeleton contains about 60% protein and 40% chitin. The predominant amino acids are arginine, glutamic acid, alanine, aspartic acid, and threonine

  8. Chitin utilization by the insect-transmitted bacterium Xylella fastidiosa.

    Science.gov (United States)

    Killiny, Nabil; Prado, Simone S; Almeida, Rodrigo P P

    2010-09-01

    Xylella fastidiosa is an insect-borne bacterium that colonizes xylem vessels of a large number of host plants, including several crops of economic importance. Chitin is a polysaccharide present in the cuticle of leafhopper vectors of X. fastidiosa and may serve as a carbon source for this bacterium. Biological assays showed that X. fastidiosa reached larger populations in the presence of chitin. Additionally, chitin induced phenotypic changes in this bacterium, notably increasing adhesiveness. Quantitative PCR assays indicated transcriptional changes in the presence of chitin, and an enzymatic assay demonstrated chitinolytic activity by X. fastidiosa. An ortholog of the chitinase A gene (chiA) was identified in the X. fastidiosa genome. The in silico analysis revealed that the open reading frame of chiA encodes a protein of 351 amino acids with an estimated molecular mass of 40 kDa. chiA is in a locus that consists of genes implicated in polysaccharide degradation. Moreover, this locus was also found in the genomes of closely related bacteria in the genus Xanthomonas, which are plant but not insect associated. X. fastidiosa degraded chitin when grown on a solid chitin-yeast extract-agar medium and grew in liquid medium with chitin as the sole carbon source; ChiA was also determined to be secreted. The gene encoding ChiA was cloned into Escherichia coli, and endochitinase activity was detected in the transformant, showing that the gene is functional and involved in chitin degradation. The results suggest that X. fastidiosa may use its vectors' foregut surface as a carbon source. In addition, chitin may trigger X. fastidiosa's gene regulation and biofilm formation within vectors. Further work is necessary to characterize the role of chitin and its utilization in X. fastidiosa.

  9. Proteomic analysis of the crayfish gastrolith chitinous extracellular matrix reveals putative protein complexes and a central role for GAP 65.

    Science.gov (United States)

    Glazer, Lilah; Roth, Ziv; Weil, Simy; Aflalo, Eliahu D; Khalaila, Isam; Sagi, Amir

    2015-10-14

    Chitin is a major component of arthropod cuticles, where it forms a three-dimensional network that constitutes the scaffold upon which cuticles form. The chitin fibers that form this network are closely associated with specific structural proteins, while the cuticular matrix contains many additional structural, enzymatic and other proteins. We study the crayfish gastrolith as a simple model for the assembly of calcified cuticular structures, with particular focus on the proteins involved in this process. The present study integrates a gastrolith-forming epithelium transcriptomic library with data from mass spectrometry analysis of proteins extracted from the gastrolith matrix to obtain a near-complete picture of gastrolith protein content. Using native protein separation we identified 24 matrix proteins, of which 14 are novel. Further analysis led to discovery of three putative protein complexes, all containing GAP 65 the most abundant gastrolith structural protein. Using immunological methods we further studied the role of GAP 65 in the gastrolith matrix and forming epithelium, as well as in the newly identified protein complexes. We propose that gastrolith matrix construction is a sequential process in which protein complexes are dynamically assembled and disassembled around GAP 65, thus changing their functional properties to perform each step in the construction process. The scientific interest on which this study is based arises from three main features of gastroliths: (1) Gastroliths possess partial analogy to cuticles both in structural and molecular properties, and may be regarded, with the appropriate reservations (see Introduction), as simple models for cuticle assembly. At the same time, gastroliths are terminally assembled during a well-defined period, which can be controlled in the laboratory, making them significantly easier to study than cuticles. (2) Gastroliths, like the crayfish exoskeleton, contain stable amorphous calcium carbonate (ACC) rather

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

    Science.gov (United States)

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

    1998-01-01

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

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

    OpenAIRE

    Oh, Dongyeop X.; Shin, Sara; Lim, Chanoong; Hwang, Dong Soo

    2013-01-01

    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 mecha...

  12. Nanosphere Lithography of Chitin and Chitosan with Colloidal and Self-Masking Patterning

    Directory of Open Access Journals (Sweden)

    Rakkiyappan Chandran

    2018-02-01

    Full Text Available Complex surface topographies control, define, and determine the properties of insect cuticles. In some cases, these nanostructured materials are a direct extension of chitin-based cuticles. The cellular mechanisms that generate these elaborate chitin-based structures are unknown, and involve complicated cellular and biochemical “bottom-up” processes. We demonstrated that a synthetic “top-down” fabrication technique—nanosphere lithography—generates surfaces of chitin or chitosan that mimic the arrangement of nanostructures found on the surface of certain insect wings and eyes. Chitin and chitosan are flexible and biocompatible abundant natural polymers, and are a sustainable resource. The fabrication of nanostructured chitin and chitosan materials enables the development of new biopolymer materials. Finally, we demonstrated that another property of chitin and chitosan—the ability to self-assemble nanosilver particles—enables a novel and powerful new tool for the nanosphere lithographic method: the ability to generate a self-masking thin film. The scalability of the nanosphere lithographic technique is a major limitation; however, the silver nanoparticle self-masking enables a one-step thin-film cast or masking process, which can be used to generate nanostructured surfaces over a wide range of surfaces and areas.

  13. 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.

  14. The cuticle and plant defense to pathogens

    Directory of Open Access Journals (Sweden)

    Jean-Pierre eMetraux

    2014-06-01

    Full Text Available The cuticle provides a physical barrier against water loss and protects against irradiation, xenobiotics and pathogens. Components of the cuticle are perceived by invading fungi and activate developmental processes during pathogenesis. In addition, cuticle alterations of various types induce a syndrome of reactions that often results in resistance to necrotrophs. This article reviews the current knowledge on the role of the cuticle in relation to the perception of pathogens and activation of defenses.

  15. Chitin Scaffolds in Tissue Engineering

    Science.gov (United States)

    Jayakumar, Rangasamy; Chennazhi, Krishna Prasad; Srinivasan, Sowmya; Nair, Shantikumar V.; Furuike, Tetsuya; Tamura, Hiroshi

    2011-01-01

    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. PMID:21673928

  16. 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....

  17. 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

  18. Ultrastructure of cuticle deposited inPlodia interpunctella wing discs after variousβ-ecdysone treatments in vitro.

    Science.gov (United States)

    Dutkowski, A B; Oberlander, H; Leach, C E

    1977-06-01

    Wing discs of the Indian meal moth may be cultured for extended periods in vitro. The discs produced a tanned cuticle after continuous incubation with β-ecdysone in medium conditioned with fat body or after a 24-h pulse incubation with β-ecdysone in plain medium. We investigated the ultrastructure of the cuticle deposited by such discs. We found that the treatment that produced the most complete cuticle in vitro was the 24-h pulse of hormone. We observed that cuticle formation in vitro was not "all-or-none." Depending on culture conditions, discs produced cuticulin only, complete epicuticle, epicuticle plus diffuse endocuticle, epicuticle plus lamellate endocuticle, or even multiple layers of cuticle. The ultrastructural evidence suggests that continuous incubation with β-ecdysone in plain medium does not always inhibit cuticle formationper se, but does prevent tanning of the partially formed cuticle.

  19. Mechanism of Cuticle Hole Development in Human Hair Due to UV-Radiation Exposure

    Directory of Open Access Journals (Sweden)

    Kazuhisa Maeda

    2018-03-01

    Full Text Available Hair is easily damaged by ultraviolet (UV radiation, bleaching agents or permanent wave treatments, and as damage progresses, hair loses its gloss, develops split ends and breaks. However, the causes of hair damage due to UV radiation have not yet been clarified. We discovered that in one mechanism facilitating damage to wet hair by UV radiation, the unsaturated fatty acids in wet hair produce hydroxy radicals upon exposure to UV radiation, and these radicals produce cuticle holes between the cuticle layers. In wet hair exposed to UV radiation, cuticle holes were produced only between the cuticle layers, whereas when human hair was immersed in a solution containing hydroxy radicals produced by Fenton’s reaction, a random production of cuticle holes was noted. It is thought that hydroxy radicals are produced only between the cuticle layers by exposure to UV radiation, and cuticle holes are formed only in this region because one of the polyunsaturated fatty acids, linoleic acid, with a bis-allyl hydrogen, is found between the cuticle layers.

  20. Biopolymer chitin: extraction and characterization

    International Nuclear Information System (INIS)

    Andrade, Sania M.B. de; Ladchumananandasivam, Rasiah

    2011-01-01

    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. Cuticle hydrolysis in four medically important fly species by enzymes of the entomopathogenic fungus Conidiobolus coronatus.

    Science.gov (United States)

    Boguś, M I; Włóka, E; Wrońska, A; Kaczmarek, A; Kazek, M; Zalewska, K; Ligęza-Żuber, M; Gołębiowski, M

    2017-03-01

    Entomopathogenic fungi infect insects via penetration through the cuticle, which varies remarkably in chemical composition across species and life stages. Fungal infection involves the production of enzymes that hydrolyse cuticular proteins, chitin and lipids. Host specificity is associated with fungus-cuticle interactions related to substrate utilization and resistance to host-specific inhibitors. The soil fungus Conidiobolus coronatus (Constantin) (Entomophthorales: Ancylistaceae) shows virulence against susceptible species. The larvae and pupae of Calliphora vicina (Robineau-Desvoidy) (Diptera: Calliphoridae), Calliphora vomitoria (Linnaeus), Lucilia sericata (Meigen) (Diptera: Calliphoridae) and Musca domestica (Linnaeus) (Diptera: Muscidae) are resistant, but adults exposed to C. coronatus quickly perish. Fungus was cultivated for 3 weeks in a minimal medium. Cell-free filtrate, for which activity of elastase, N-acetylglucosaminidase, chitobiosidase and lipase was determined, was used for in vitro hydrolysis of the cuticle from larvae, puparia and adults. Amounts of amino acids, N-glucosamine and fatty acids released were measured after 8 h of incubation. The effectiveness of fungal enzymes was correlated with concentrations of compounds detected in the cuticles of tested insects. Positive correlations suggest compounds used by the fungus as nutrients, whereas negative correlations may indicate compounds responsible for insect resistance. Adult deaths result from the ingestion of conidia or fungal excretions. © 2016 The Royal Entomological Society.

  2. 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...

  3. 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.

  4. Leaf cuticles as mediators of environmental influences: new developments in the use of isolated cuticles

    International Nuclear Information System (INIS)

    Scherbatskoy, T.

    1994-01-01

    Isolated leaf cuticles have been used in our research to characterize trans-cuticular ion diffusion rates under various environmental treatments and to measure cuticular attenuation of solar radiation. These studies have been conducted to understand better the role of the leaf cuticle as a protective barrier against potential environmental stressors including acid rain, ozone and ultraviolet radiation. These studies provide examples of a variety of current research uses for isolated leaf cuticles. Ion permeability coefficients and exchange rates in isolated cuticles of Acer, Prunus and Citrus species have been studied using several experimental approaches, including measurement of adsorption kinetics, electrical potential and conductance, and perfusion rates. Measured electrical (diffusion) potentials under KCl gradients across isolated cuticles are positive, indicating greater cation permeability. Electrical potentials (and permeability coefficients) vary with ionic strength and pH, and affect the driving force for ion diffusion through cuticles. Ion permeability in cuticles of Prunus serotina foliage was affected by experimental exposure to ozone and ultraviolet treatments. These studies indicate that cuticle permeability properties can be significantly altered by environmental factors. These and related studies on the ion exchange kinetics of Acer saccharum leaf cuticles suggest that foliar ''leaching'' is dominated by cuticle surface exchange mechanisms, with the magnitude of cuticular ion permeation being relatively small. In working with various hardwood species, we observed that the success rate for cuticle isolation varies with tree species and time of year. Scanning electron micrographs of inner cuticle surfaces indicate that the effects of enzymatic digestion could vary with exposure time, possibly affecting transport properties of isolated cuticles. Experimental work to test this in Citrus, however, showed no significant effect of isolation time on

  5. Cuticle microstructure as a new tool in systematic paleontology

    OpenAIRE

    Waugh, David A.; Feldmann, Rodney M.

    2003-01-01

    Fossil decapod cuticle has received little systematic study. The purpose of the present note is to survey the cuticle architecture of eleven extant decapod crabs arrayed within ten families, and to develop a classification scheme of cuticle types suitable for describing fossil and Recent decapod cuticle morphology.

  6. Acid Mucopolysaccharide of the Crustacean Cuticle.

    Science.gov (United States)

    Meenakshi, V R; Scheer, B T

    1959-10-30

    The acid mucopolysaccharide found in the crab Hemigrapsus nudus and containing glucose, galactose, and fucose residues is found both in the cuticle and in the digestive gland of the crab. The concentration of mucopolysaccharide is somewhat higher in the cuticle, where it it the only soluble polysaccharide, than in the digestive gland, where it makes up 10 to 25 percent of the total polysaccharide content.

  7. Stiffness distribution in insect cuticle: a continuous or a discontinuous profile?

    Science.gov (United States)

    Rajabi, H; Jafarpour, M; Darvizeh, A; Dirks, J-H; Gorb, S N

    2017-07-01

    Insect cuticle is a biological composite with a high degree of complexity in terms of both architecture and material composition. Given the complex morphology of many insect body parts, finite-element (FE) models play an important role in the analysis and interpretation of biomechanical measurements, taken by either macroscopic or nanoscopic techniques. Many previous studies show that the interpretation of nanoindentation measurements of this layered composite material is very challenging. To develop accurate FE models, it is of particular interest to understand more about the variations in the stiffness through the thickness of the cuticle. Considering the difficulties of making direct measurements, in this study, we use the FE method to analyse previously published data and address this issue numerically. For this purpose, sets of continuous or discontinuous stiffness profiles through the thickness of the cuticle were mathematically described. The obtained profiles were assigned to models developed based on the cuticle of three insect species with different geometries and layer configurations. The models were then used to simulate the mechanical behaviour of insect cuticles subjected to nanoindentation experiments. Our results show that FE models with discontinuous exponential stiffness gradients along their thickness were able to predict the stress and deformation states in insect cuticle very well. Our results further suggest that, for more accurate measurements and interpretation of nanoindentation test data, the ratio of the indentation depth to cuticle thickness should be limited to 7% rather than the traditional '10% rule'. The results of this study thus might be useful to provide a deeper insight into the biomechanical consequences of the distinct material distribution in insect cuticle and also to form a basis for more realistic modelling of this complex natural composite. © 2017 The Author(s).

  8. Regulation of cuticle-degrading subtilisin proteases from the entomopathogenic fungi, Lecanicillium spp: implications for host specificity.

    Science.gov (United States)

    Bye, Natasha J; Charnley, A Keith

    2008-01-01

    The ability to produce cuticle-degrading proteases to facilitate host penetration does not distinguish per se entomopathogenic fungi from saprophytes. However, adapted pathogens may produce host-protein specific enzymes in response to cues. This possibility prompted an investigation of the regulation of isoforms of the subtilisin Pr1-like proteases from five aphid-pathogenic isolates of Lecanicillium spp. Significant differences were found in substrate specificity and regulation of Pr1-like proteases between isoforms of the same isolate and between different isolates. For example, the pI 8.6 isoform from KV71 was considerably more active against aphid than locust cuticle and was induced specifically by N-acetylglucosamine (NAG). Isoform pI 9.1 from the same isolate was only produced on insect cuticle while most other isoforms were more prominent on chitin containing substrates but not induced by NAG. The ability to regulate isoforms independently may allow production at critical points in host penetration. Appearance of proteases (not subtilisins) with pI 4.2 and 4.4 only on aphid cuticle was a possible link with host specificity of KV71. The absence of C or N metabolite repression in subtilisins from KV42 is unusual for pathogen proteases and may help to account for differences in virulence strategy between aphid-pathogenic isolates of Lecanicillium longisporum (unpublished data).

  9. High similarity in physicochemical properties of chitin and chitosan from nymphs and adults of a grasshopper.

    Science.gov (United States)

    Erdogan, Sevil; Kaya, Murat

    2016-08-01

    This is the first study to explain the differences in the physicochemical properties of chitin and chitosan obtained from the nymphs and adults of Dociostaurus maroccanus using the same method. Fourier transform infrared spectroscopy, thermogravimetric analysis and x-ray diffraction analysis results demonstrated that the chitins from both the adults and nymphs were in the α-form. The chitin contents of the adults (14%) and nymphs (12%) were of the same order of magnitude. The crystalline index values of chitins from the adult and nymph grasshoppers were 71% and 74%, respectively. Thermal stabilities of the chitins and chitosans from adult and nymph grasshoppers were close to each other. Both the adult (7.2kDa) and nymph (5.6kDa) chitosans had low molar masses. Environmental scanning electron microscopy revealed that the surface morphologies of both chitins consisted of nanofibers and nanopores together, and they were very similar to each other. Consequently, it was determined that the physicochemical properties of the chitins and chitosans from adults and nymphs of D. maroccanus were not very different, so it can be hypothesized that the development of the chitin structure in the nymph has almost been completed and the nymph chitin has the same characteristics as the adult. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. 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.

  11. 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

  12. Yeast cell wall chitin reduces wine haze formation.

    Science.gov (United States)

    Ndlovu, Thulile; Divol, Benoit; Bauer, Florian F

    2018-04-27

    Protein haze formation in bottled wines is a significant concern for the global wine industry and wine clarification before bottling is therefore a common but expensive practice. Previous studies have shown that wine yeast strains can reduce haze formation through the secretion of certain mannoproteins, but it has been suggested that other yeast-dependent haze protective mechanisms exist. On the other hand, addition of chitin has been shown to reduce haze formation, likely because grape chitinases have been shown to be the major contributors to haze. In this study, Chardonnay grape must fermented by various yeast strains resulted in wines with different protein haze levels indicating differences in haze protective capacities of the strains. The cell wall chitin levels of these strains were determined, and a strong correlation between cell wall chitin levels and haze protection capability was observed. To further evaluate the mechanism of haze protection, Escherichia coli -produced GFP-tagged grape chitinase was shown to bind efficiently to yeast cell walls in a cell wall chitin concentration-dependent manner, while commercial chitinase was removed from synthetic wine in quantities also correlated with the cell wall chitin levels of the strains. Our findings suggest a new mechanism of reducing wine haze, and propose a strategy for optimizing wine yeast strains to improve wine clarification. Importance In this study, we establish a new mechanism by which wine yeast strains can impact on the protein haze formation of wines, and demonstrate that yeast cell wall chitin binds grape chitinase in a chitin-concentration dependent manner. We also show that yeast can remove this haze-forming protein from wine. Chitin has in the past been shown to efficiently reduce wine haze formation when added to the wine in high concentration as a clarifying agent. Our data suggest that the selection of yeast strains with high levels of cell wall chitin can reduce protein haze. We also

  13. 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.

  14. Pathogenicity of Beauveria bassiana and production of cuticle ...

    African Journals Online (AJOL)

    aghomotsegin

    2013-11-13

    Nov 13, 2013 ... cuticle-degrading enzymes in the presence of Diatraea saccharalis cuticle .... the bioassays, each larva was confined individually in plastic containers (17 x 21 x 25 ..... nism (virus, bacteria and protozoa). Only entomo-patho-.

  15. Cuticle microstructure as a new tool in systematic paleontology

    NARCIS (Netherlands)

    Waugh, David A.; Feldmann, Rodney M.

    2003-01-01

    Fossil decapod cuticle has received little systematic study. The purpose of the present note is to survey the cuticle architecture of eleven extant decapod crabs arrayed within ten families, and to develop a classification scheme of cuticle types suitable for describing fossil and Recent decapod

  16. PROPERTIES OF CHITIN REINFORCES COMPOSITES: A REVIEW

    African Journals Online (AJOL)

    user

    mechanical and thermal properties of chitin reinforced composites. ..... with crabyon fiber and normal viscose filaments. Also. Zhang et al.,[65] successfully blended chitin/cellulose using two different coagulating systems (immersed in 5.

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

    Energy Technology Data Exchange (ETDEWEB)

    Kaya, Murat, E-mail: muratkaya3806@yahoo.com [Department of Biotechnology and Molecular Biology, Faculty of Science and Letters, Aksaray University, 68100 Aksaray (Turkey); Mulerčikas, Povilas [Department of Biology and Plant Protection, Lithuanian University of Agriculture, LT-53361 (Lithuania); Sargin, Idris [Department of Chemistry, Faculty of Science, Selcuk University, 42075 Konya (Turkey); Kazlauskaitė, Sonata [Department of Biology and Plant Protection, Lithuanian University of Agriculture, LT-53361 (Lithuania); Baublys, Vykintas [Department of Biology, Vytautas Magnus University, LT-44404 Kaunas (Lithuania); Akyuz, Bahar; Bulut, Esra [Department of Biotechnology and Molecular Biology, Faculty of Science and Letters, Aksaray University, 68100 Aksaray (Turkey); Tubelytė, Vaida [Department of Biology, Vytautas Magnus University, LT-44404 Kaunas (Lithuania)

    2016-11-01

    Physicochemical characterization of new chitin isolates can provide valuable insights into designing of biomimetic materials. Chitin isolates with a definite three-dimensional (3D) structure can exhibit characteristics that distinguish them from other chitin specimens that are in form of powder or flakes without a definite and uniform shape. Herein, 3D chitin rings were produced from body segments of a diplopod (Archispirostreptus gigas) inhabiting tropical regions. This organism is cultured easily and can reach 38 cm in length, which makes it a suitable source for isolation of chitin. The chitin rings were characterized via TGA, FT-IR, SEM and XRD analyses. Enzymatic digestion test with chitinase demonstrated that chitin isolates had high purity (digestion rate: 97.4%). The source organism had high chitin content; 21.02 ± 2.23% on dry weight. Interactions of the chitin rings with bovine serum albumin (BSA) protein were studied under different conditions (pH: 4.0–8.0, chitin amount: 6–14 mg, contact time: 30–360 min, protein concentration: 0.2–1 mg/mL). The highest BSA adsorption was observed at pH 5.0 at 20 °C. The adsorption equilibrium data exhibited a better fit to Langmuir adsorption and the pseudo-first order kinetic models. The findings presented here can be useful for further studies aiming to develop biocompatible and nontoxic biomaterials. - Highlights: • Three-dimensional ring shaped chitin was produced from a pet diplopod species. • Archispirostreptus gigas has high chitin content; 21.02 ± 2.23% on dry weight. • Chitinase enzyme showed activity on the chitin rings with digestion rate of 97.4%. • The highest bovine serum albumin (BSA) adsorption was observed at pH 5.0 at 20 °C.

  18. Cuticles of European and American lobsters harbor diverse bacterial species and differ in disease susceptibility.

    Science.gov (United States)

    Whitten, Miranda M A; Davies, Charlotte E; Kim, Anita; Tlusty, Michael; Wootton, Emma C; Chistoserdov, Andrei; Rowley, Andrew F

    2014-06-01

    Diseases of lobster shells have a significant impact on fishing industries but the risk of disease transmission between different lobster species has yet to be properly investigated. This study compared bacterial biofilm communities from American (Homarus americanus) and European lobsters (H. gammarus), to assess both healthy cuticle and diseased cuticle during lesion formation. Culture-independent molecular techniques revealed diversity in the bacterial communities of cuticle biofilms both within and between the two lobster species, and identified three bacterial genera associated with shell lesions plus two putative beneficial bacterial species (detected exclusively in healthy cuticle or healing damaged cuticle). In an experimental aquarium shared between American and European lobsters, heterospecific transmission of potentially pathogenic bacteria appeared to be very limited; however, the claws of European lobsters were more likely to develop lesions when reared in the presence of American lobsters. Aquarium biofilms were also examined but revealed no candidate pathogens for environmental transmission. Aquimarina sp. 'homaria' (a potential pathogen associated with a severe epizootic form of shell disease) was detected at a much higher prevalence among American than European lobsters, but its presence correlated more with exacerbation of existing lesions rather than with lesion initiation. © 2014 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

  19. Fabrication of magnetic and fluorescent chitin and dibutyrylchitin sub-micron particles by oil-in-water emulsification.

    Science.gov (United States)

    Blanco-Fernandez, Barbara; Chakravarty, Shatadru; Nkansah, Michael K; Shapiro, Erik M

    2016-11-01

    Chitin is a carbohydrate polymer with unique pharmacological and immunological properties, however, because of its unwieldy chemistry, the synthesis of discreet sized sub-micron particles has not been well reported. This work describes a facile and flexible method to fabricate biocompatible chitin and dibutyrylchitin sub-micron particles. This technique is based on an oil-in-water emulsification/evaporation method and involves the hydrophobization of chitin by the addition of labile butyryl groups onto chitin, disrupting intermolecular hydrogen bonds and enabling solubility in the organic solvent used as the oil phase during fabrication. The subsequent removal of butyryl groups post-fabrication through alkaline saponification regenerates native chitin while keeping particles morphology intact. Examples of encapsulation of hydrophobic dyes and nanocrystals are demonstrated, specifically using iron oxide nanocrystals and coumarin 6. The prepared particles had diameters between 300-400nm for dibutyrylchitin and 500-600nm for chitin and were highly cytocompatible. Moreover, they were able to encapsulate high amounts of iron oxide nanocrystals and were able to label mammalian cells. We describe a technique to prepare sub-micron particles of highly acetylated chitin (>90%) and dibutyrylchitin and demonstrate their utility as carriers for imaging. Chitin is a polysaccharide capable of stimulating the immune system, a property that depends on the acetamide groups, but its insolubility limits its use. No method for sub-micron particle preparation with highly acetylated chitins have been published. The only approach for the preparation of sub-micron particles uses low acetylation chitins. Dibutyrylchitin, a soluble chitin derivative, was used to prepare particles by oil in water emulsification. Butyryl groups were then removed, forming chitin particles. These particles could be suitable for encapsulation of hydrophobic payloads for drug delivery and cell imaging, as well as

  20. Fruit cuticle lipid composition and fruit post-harvest water loss in an advanced backcross generation of pepper (Capsicum sp.)

    KAUST Repository

    Parsons, Eugene P.; Popopvsky, Sigal; Lohrey, Gregory T.; Lu, Shiyou; Alkalai-Tuvia, Sharon; Perzelan, Yaacov; Paran, Ilan; Fallik, Elazar; Jenks, Matthew A.

    2012-01-01

    To understand the role of fruit cuticle lipid composition in fruit water loss, an advanced backcross population, the BC2F2, was created between the Capsicum annuum (PI1154) and the Capsicum chinense (USDA162), which have high and low post-harvest water loss rates, respectively. Besides dramatic differences in fruit water loss, preliminary studies also revealed that these parents exhibited significant differences in both the amount and composition of their fruit cuticle. Cuticle analysis of the BC2F2 fruit revealed that although water loss rate was not strongly associated with the total surface wax amount, there were significant correlations between water loss rate and cuticle composition. We found a positive correlation between water loss rate and the amount of total triterpenoid plus sterol compounds, and negative correlations between water loss and the alkane to triterpenoid plus sterol ratio. We also report negative correlations between water loss rate and the proportion of both alkanes and aliphatics to total surface wax amount. For the first time, we report significant correlations between water loss and cutin monomer composition. We found positive associations of water loss rate with the total cutin, total C16 monomers and 16-dihydroxy hexadecanoic acid. Our results support the hypothesis that simple straight-chain aliphatic cuticle constituents form more impermeable cuticular barriers than more complex isoprenoid-based compounds. These results shed new light on the biochemical basis for cuticle involvement in fruit water loss. © 2012 Physiologia Plantarum.

  1. Fruit cuticle lipid composition and fruit post-harvest water loss in an advanced backcross generation of pepper (Capsicum sp.)

    KAUST Repository

    Parsons, Eugene P.

    2012-03-05

    To understand the role of fruit cuticle lipid composition in fruit water loss, an advanced backcross population, the BC2F2, was created between the Capsicum annuum (PI1154) and the Capsicum chinense (USDA162), which have high and low post-harvest water loss rates, respectively. Besides dramatic differences in fruit water loss, preliminary studies also revealed that these parents exhibited significant differences in both the amount and composition of their fruit cuticle. Cuticle analysis of the BC2F2 fruit revealed that although water loss rate was not strongly associated with the total surface wax amount, there were significant correlations between water loss rate and cuticle composition. We found a positive correlation between water loss rate and the amount of total triterpenoid plus sterol compounds, and negative correlations between water loss and the alkane to triterpenoid plus sterol ratio. We also report negative correlations between water loss rate and the proportion of both alkanes and aliphatics to total surface wax amount. For the first time, we report significant correlations between water loss and cutin monomer composition. We found positive associations of water loss rate with the total cutin, total C16 monomers and 16-dihydroxy hexadecanoic acid. Our results support the hypothesis that simple straight-chain aliphatic cuticle constituents form more impermeable cuticular barriers than more complex isoprenoid-based compounds. These results shed new light on the biochemical basis for cuticle involvement in fruit water loss. © 2012 Physiologia Plantarum.

  2. 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.

  3. Determination of chitin in Claviceps

    Energy Technology Data Exchange (ETDEWEB)

    Schmauder, H P; Groeger, D [Akademie der Wissenschaften der DDR, Halle/Saale. Inst. fuer Biochemie der Pflanzen

    1978-01-01

    Preparations rich in chitin obtained from the cell walls of ergot fungi were studied by X-ray diffraction and IR-techniques. During the course of fermentation, the yield of chitin was determined using a modified procedure according to Ride and Drysdale (1972). A saprophytic ergotoxine-producing Claviceps purpurea strain (Pepty 695) was found to contain 7-9 ..mu..g glucosamine/mg dry weight of the mycelium in contrast to 3-5 ..mu..g glucosamine/mg dry weight of a non-alkaloid producing C. purpurea strain (PUR 212). There was no remarkable fluctuation of the glucosamine content in strain Pepty 695 during the course of fermentation.

  4. Development of Coprocessed Chitin-Calcium Carbonate as Multifunctional Tablet Excipient for Direct Compression.

    Science.gov (United States)

    Chaheen, Mohammad; Sanchez-Ballester, Noelia M; Bataille, Bernard; Yassine, Ahmad; Belamie, Emmanuel; Sharkawi, Tahmer

    2018-04-24

    Owing to the increasing interest in multifunctional excipients for tableting, coprocessing of individual excipients is regularly used to produce excipients of improved multifunctionality superior to individual excipients or their physical mix. The use of chitin as an excipient in tablet formulation is limited because of certain drawbacks such as poor flowability and low true density. The objective of this work is to improve these properties through coprocessing of chitin with calcium carbonate (CaCO 3 ) by precipitating CaCO 3 on chitin particles using different methods. In addition, optimization of the coprocessed chitin was carried out to improve the excipient's properties. Physicochemical (CaCO 3 content, true density, X-ray diffraction, infrared spectroscopy, and scanning electron microscopy) and functional testing (swelling force, flowability, tensile strength, deformation mechanism, and disintegration time) were used to characterize the coprocessed product. Results showed that the calcite CaCO 3 polymorph is precipitated on the chitin surface and that it interacts with chitin at carbonyl- and amide-group level. In addition, the coprocessed excipient has an improved true density and powder flowability, with CaCO 3 forming single layer on the chitin particles surface. Tableting studies showed that the coprocessed powder exhibited an intermediate deformation behavior between CaCO 3 (most brittle) and chitin (most plastic). Tablets showed acceptable tensile strength and rapid disintegration (2-4 s). These results show the potential use of coprocessed chitin-CaCO 3 as a multifunctional excipient for fast disintegration of tablets produced by direct compression. Copyright © 2018 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  5. Cuticle hydrocarbons in saline aquatic beetles

    Directory of Open Access Journals (Sweden)

    María Botella-Cruz

    2017-07-01

    Full Text Available Hydrocarbons are the principal component of insect cuticle and play an important role in maintaining water balance. Cuticular impermeability could be an adaptative response to salinity and desiccation in aquatic insects; however, cuticular hydrocarbons have been poorly explored in this group and there are no previous data on saline species. We characterized cuticular hydrocarbons of adults and larvae of two saline aquatic beetles, namely Nebrioporus baeticus (Dytiscidae and Enochrus jesusarribasi (Hydrophilidae, using a gas chromatograph coupled to a mass spectrometer. The CHC profile of adults of both species, characterized by a high abundance of branched alkanes and low of unsaturated alkenes, seems to be more similar to that of some terrestrial beetles (e.g., desert Tenebrionidae compared with other aquatic Coleoptera (freshwater Dytiscidae. Adults of E. jesusarribasi had longer chain compounds than N. baeticus, in agreement with their higher resistance to salinity and desiccation. The more permeable cuticle of larvae was characterized by a lower diversity in compounds, shorter carbon chain length and a higher proportion of unsaturated hydrocarbons compared with that of the adults. These results suggest that osmotic stress on aquatic insects could exert a selection pressure on CHC profile similar to aridity in terrestrial species.

  6. Cuticle of 'Gala' and 'Galaxy' apples cultivars under different environmental conditions

    Directory of Open Access Journals (Sweden)

    Magda Andréia Tessmer

    2012-10-01

    Full Text Available This study aimed to analyze the cuticle thickness and pattern of epicuticular wax deposition in 'Gala' and 'Galaxy' apple cultivars (Malus domestica Borkh, from three Brazilian producing areas: Vacaria (RS, Fraiburgo (SC and São Joaquim (SC with altitudes of 971, 1,048 and 1,353m, respectively. Harvested fruit were kept under two storage conditions: regular atmosphere (RA (0 ºC and 90% RH and controlled atmosphere (CA (1.5% O2, 2.5% CO2, 0ºC and 90% RH. Cuticle thickness measurements were made using LM and the deposition pattern of epicuticular wax observed with a SEM. Altitude among the apple producing areas was not a factor in deposition pattern of waxes between the cultivars but at higher altitudes, the cuticle was thicker in both the cultivars. In the freshly-harvested fruits, waxes deposition in the form of platelets and the mechanism of “tear and repair” were observed. Severity of microcracks in the cuticle was more evident on the fruits from CA.

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

    Directory of Open Access Journals (Sweden)

    Mayumi eEgusa

    2015-12-01

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

  8. 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.

  9. "Chitin-specific" peroxidases in plants.

    Science.gov (United States)

    Maksimov, I V; Cherepanova, E A; Khairullin, R M

    2003-01-01

    The activity of various plant peroxidases and the ability of their individual isoforms to bind chitin was studied. Some increase in peroxidase activity was observed in crude extracts in the presence of chitin. Activated peroxidases of some species fell in the fraction not sorbed on chitin and those of other species can bind chitin. Only anionic isoperoxidases from oat (Avena sativa), rice (Oryza sativa), horseradish (Armoracia rusticana), garden radish (Raphanus sativus var. radicula), peanut (Arachis hypogaea), and tobacco (Nicotiana tabacum Link et Otto) were sorbed on chitin. Both anionic and cationic isoforms from pea (Pisum sativum), galega(Galega orientalis), cucumber (Cucumis sativus), and zucchini (Cucurbita pepo L.) were sorbed on chitin. Peroxidase activation under the influence of chitin was correlated to the processes that occur during hypersensitive reaction and lignification of sites, in which pathogenic fungus penetrates into a plant. The role of chitin-specific isoperoxidases in inhibition of fungal growth and connection of this phenomenon with structural characteristics of isoperoxidases are also discussed.

  10. Properties of polymethyl methacrylate-based nanocomposites: Reinforced with ultra-long chitin nanofiber extracted from crab shells

    International Nuclear Information System (INIS)

    Chen, Chuchu; Li, Dagang; Hu, Qinqin; Wang, Ru

    2014-01-01

    Highlights: • Using waste crab shells to develop high-performance composites by simple method. • Combining the anatomic analysis of crab shell with the design of composite. • Introducing a 4-step all-mechanical treatment to prepare ultra-long chitin fiber. • Incorporation of chitin nanofiber improves properties of PMMA/Chitin composite. - Abstract: Ultra-long chitin nanofibers were incorporated into polymethyl methacrylate (PMMA) resin to prepared PMMA/Chitin nanocomposites with improved properties. Transmission electron microscopy (TEM) images showed that through the introduced 4-step all-mechanical treatment, the average aspect ratio of the obtained chitin fiber was up to 1000 with the length at dozens of micron range. Due to the laminated structure formed by “layer-by-layer” effect, tensile strength and Young’s modulus of the prepared composite were significantly enhanced after the filling of chitin nanofibers, as compared with neat PMMA. Light transmittance test indicated that increasing the fiber content causes little light scattering because the nano-scalar network which is smaller enough than the visible wavelength could well preserve the original transparency of PMMA. Furthermore, chitin nanofiber film with extremely low thermal expansion improved the thermal stability of PMMA in a great degree. This could lead to various commercial applications including flexible electronic printing, organic thin-film photovoltaic devices, and is a significantly environmental move towards the sustainable utilization of marine-river crab shell wastes

  11. Cuticle lipids on heteromorphic leaves of Populus euphratica Oliv. growing in riparian habitats differing in available soil moisture.

    Science.gov (United States)

    Xu, Xiaojing; Xiao, Lei; Feng, Jinchao; Chen, Ningmei; Chen, Yue; Song, Buerbatu; Xue, Kun; Shi, Sha; Zhou, Yijun; Jenks, Matthew A

    2016-11-01

    Populus euphratica is an important native tree found in arid regions from North Africa and South Europe to China, and is known to tolerate many forms of environmental stress, including drought. We describe cuticle waxes, cutin and cuticle permeability for the heteromorphic leaves of P. euphratica growing in two riparian habitats that differ in available soil moisture. Scanning electron microscopy revealed variation in epicuticular wax crystallization associated with leaf type and site. P. euphratica leaves are dominated by cuticular wax alkanes, primary-alcohols and fatty acids. The major cutin monomers were 10,16-diOH C 16 :0 acids. Broad-ovate leaves (associated with adult phase growth) produced 1.3- and 1.6-fold more waxes, and 2.1- and 0.9-fold more cutin monomers, than lanceolate leaves (associated with juvenile phase growth) at the wetter site and drier site, respectively. The alkane-synthesis-associated ECERIFERUM1 (CER1), as well as ABC transporter- and elongase-associated genes, were expressed at much higher levels at the drier than wetter sites, indicating their potential function in elevating leaf cuticle lipids in the dry site conditions. Higher cuticle lipid amounts were closely associated with lower cuticle permeability (both chlorophyll efflux and water loss). Our results implicate cuticle lipids as among the xeromorphic traits associated with P. euphratica adult-phase broad-ovate leaves. Results here provide useful information for protecting natural populations of P. euphratica and their associated ecosystems, and shed new light on the functional interaction of cuticle and leaf heterophylly in adaptation to more arid, limited-moisture environments. © 2016 Scandinavian Plant Physiology Society.

  12. New analytical techniques for cuticle chemical analysis

    International Nuclear Information System (INIS)

    Schulten, H.R.

    1994-01-01

    1) The analytical methodology of pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and direct pyrolysis-mass spectrometry (Py-MS) using soft ionization techniques by high electric fields (FL) are briefly described. Recent advances of Py-GC/MS and Py-FIMS for the analyses of complex organic matter such as plant materials, humic substances, dissolved organic matter in water (DOM) and soil organic matter (SOM) in agricultural and forest soils are given to illustrate the potential and limitations of the applied methods. 2) Novel applications of Py-GC/MS and Py-MS in combination with conventional analytical data in an integrated, chemometric approach to investigate the dynamics of plant lipids are reported. This includes multivariate statistical investigations on maturation, senescence, humus genesis, and environmental damages in spruce ecosystems. 3) The focal point is the author's integrated investigations on emission-induced changes of selected conifer plant constituents. Pattern recognition of Py-MS data of desiccated spruce needles provides a method for distinguishing needles damaged in different ways and determining the cause. Spruce needles were collected from both controls and trees treated with sulphur dioxide (acid rain), nitrogen dioxide, and ozone under controlled conditions. Py-MS and chemometric data evaluation are employed to characterize and classify leaves and their epicuticular waxes. Preliminary mass spectrometric evaluations of isolated cuticles of different plants such as spruce, ivy, holly, and philodendron, as well as ivy cuticles treated in vivo with air pollutants such as surfactants and pesticides are given. (orig.)

  13. 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.

  14. Interaction of chitin/chitosan with salivary and other epithelial cells-An overview.

    Science.gov (United States)

    Patil, Sharvari Vijaykumar; Nanduri, Lalitha S Y

    2017-11-01

    Chitin and its deacetylated form, chitosan, have been widely used for tissue engineering of both epithelial and mesenchymal tissues. Epithelial cells characterised by their sheet-like tight cellular arrangement and polarised nature, constitute a major component in various organs and play a variety of roles including protection, secretion and maintenance of tissue homeostasis. Regeneration of damaged epithelial tissues has been studied using biomaterials such as chitin, chitosan, hyaluronan, gelatin and alginate. Chitin and chitosan are known to promote proliferation of various embryonic and adult epithelial cells. However it is not clearly understood how this activity is achieved or what are the mechanisms involved in the chitin/chitosan driven proliferation of epithelial cells. Mechanistic understanding of influence of chitin/chitosan on epithelial cells will guide us to develop more targeted regenerative scaffold/hydrogel systems. Therefore, current review attempts to elicit a mechanistic insight into how chitin and chitosan interact with salivary, mammary, skin, nasal, lung, intestinal and bladder epithelial cells. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Identification and characterization of chitin deacetylase2 from the American white moth, Hyphantria cunea (Drury).

    Science.gov (United States)

    Yan, Xiaoping; Zhao, Dan; Zhang, Yakun; Guo, Wei; Wang, Wei; Zhao, Kunli; Gao, Yujie; Wang, Xiaoyun

    2018-05-26

    Chitin deacetylases (CDAs) are enzymes that catalyze the conversion of chitin into chitosan, thereby influence the mechanical and permeability properties of structures such as the cuticle and peritrophic matrices. The full length cDNAs of chitin deacetylase2 (CDA2) genes from Hyphantria cunea were fully cloned by PCR amplification. Two cDNA sequences of HcCDA2 were searched from transcriptome of H. cunea and named as HcCDA2a and HcCDA2b. The deduced protein sequences showed that HaCDA2a and HaCDA2b are synthesized as preproteins of 524 and 518 amino acid residues with an 18-amino acid signal peptide, respectively. HcCDA2a and HcCDA2b contained a chitin-binding domain (ChBD), a low-density lipoprotein receptor class A domain (LDLa) and a polysaccharide deacetylase-like catalytic domain (CDA). Gene expression analyses results showed that HcCDA2a and HcCDA2b were both expressed at the head, integument, foregut, midgut, hindgut, Malpighian tubules and fat body, as well as the 1st to 5th days of fifth instar larvae. Western blot analyses revealed that HcCDA2 protein was highly abundant in the head and integument, and the developmental expression result in the fifth instars showed that HcCDA2 was highly present at the first two days. Besides, RT-PCR results showed that HcCDA2a and HcCDA2b were both expressed in integument and head, whether in molting stage or feeding stage. No visiable phenotypic changes were observed after injection of dsHcCDA2b, while lethal phenotypes of cuticle shedding failure and high mortality were resulted from injection of dsHcCDA2a. The silence of HcCDA2a leads to the ecdysis failure and death of H. cunea. These results suggest that HcCDA2 plays an important role during insect development, and provide new candidate targets and basis for developing environment-friendly pesticides. Copyright © 2017. Published by Elsevier B.V.

  16. Topographical and Tribological Characteristics of Asian Human Hair Cuticles

    Directory of Open Access Journals (Sweden)

    Chia-Ling Chang

    2015-01-01

    Full Text Available The topography and frictional force of Asian black male and female hair cuticles at different locations are determined using atomic force microscopy (AFM and friction force microscopy (FFM. The frictional values, mapped for comparison with surface morphology, corresponded qualitatively with the structures’ plane surface characteristics. The results indicate that the hair surface was damaged and modified at different temperatures and heating times. The height of the female hair at a blowing temperature of 60°C after a duration of 2 min between the cuticle edge and cuticle surface was approximately 440–556 nm. The adhesion phenomenon occurs on the hair surface and interface. The cuticles do not vary after the heating; however, the hair damage sustained increases with serious deterioration.

  17. Collagenous and other organizations in mature annelid cuticle and epidermis.

    Science.gov (United States)

    Humphreys, S; Porter, K R

    1976-05-01

    The mature annelid cuticle contains orthogonally oriented collagen in a matrix capped superficially by a dense epicuticle with external corpuscles. The underlying epidermis is a simple columnar epithelium with two major cell types, mucous-secreting cells which secrete through channels in the cuticle to the exterior of the worm, and "supportive" cells which presumably produce and increase the cuticle by secreting into it. The structures of supportive cells, previously interpreted as specialized for establishing interfibrillar collagen order, are revealed by glutaraldehyde fixation as common cellular components without the qualities deemed useful to align collagen. Cell processes which penetrate and sometimes pass completely through the cuticle are not stable, not in geometric order, and lack cilia-like structure. Cilia, unlike the ubiquitous cellular processes, are highly restricted to regions of the epidermis with specialized functions. Cellular control, or other control, of collagen fibrillogenesis remains unestablished.

  18. On the function of chitin synthase extracellular domains in biomineralization.

    Science.gov (United States)

    Weiss, Ingrid M; Lüke, Florian; Eichner, Norbert; Guth, Christina; Clausen-Schaumann, Hauke

    2013-08-01

    Molluscs with various shell architectures evolved around 542-525 million years ago, as part of a larger phenomenon related to the diversification of metazoan phyla. Molluscs deposit minerals in a chitin matrix. The mollusc chitin is synthesized by transmembrane enzymes that contain several unique extracellular domains. Here we investigate the assembly mechanism of the chitin synthase Ar-CS1 via its extracellular domain ArCS1_E22. The corresponding transmembrane protein ArCS1_E22TM accumulates in membrane fractions of the expression host Dictyostelium discoideum. Soluble recombinant ArCS1_E22 proteins can be purified as monomers only at basic pH. According to confocal fluorescence microscopy experiments, immunolabeled ArCS1_E22 proteins adsorb preferably to aragonitic nacre platelets at pH 7.75. At pH 8.2 or pH 9.0 the fluorescence signal is less intense, indicating that protein-mineral interaction is reduced with increasing pH. Furthermore, ArCS1_E22 forms regular nanostructures on cationic substrates as revealed by atomic force microscopy (AFM) experiments on modified mica cleavage planes. These experiments suggest that the extracellular domain ArCS1_E22 is involved in regulating the multiple enzyme activities of Ar-CS1 such as chitin synthesis and myosin movements by interaction with mineral surfaces and eventually by protein assembly. The protein complexes could locally probe the status of mineralization according to pH unless ions and pCO2 are balanced with suitable buffer substances. Taking into account that the intact enzyme could act as a force sensor, the results presented here provide further evidence that shell formation is coordinated physiologically with precise adjustment of cellular activities to the structure, topography and stiffness at the mineralizing interface. Copyright © 2013 Elsevier Inc. All rights reserved.

  19. Air pollutants and the cuticle: implications for plant physiology

    International Nuclear Information System (INIS)

    Riederer, M.; Jetter, R.; Markstaedter, C.; Schreiber, L.

    1994-01-01

    The physiologically most important function of the plant cuticle is to control the loss of water and of inorganic and organic constituents of plants via the surfaces of leaves and fruits. In a polluted environment, the cuticle may also affect the rates of uptake of extraneous chemicals. It will be shown how the essential transport properties of plant cuticles can be determined experimentally using intact leaves, isolated cuticles, and reconstituted cuticular waxes. The transport properties will be related to the physico-chemical properties of the permeants in order to achieve a general description of pollutant transport across the leaf/atmosphere interface and to assess the relative contributions of the cuticular and the stomatal pathways to the total flow rate. The correlation of the transport properties of cuticles with their chemical composition will be discussed and a model of the molecular structure of the transport-limiting barrier of the cuticle and of epicuticular waxes be presented. The effects of chemicals of anthropogenic and biogenic origin on cuticular permeability will be described quantitatively. (orig.)

  20. Deletion of a Chitin Synthase Gene in a Citric Acid Producing Strain of Aspergillus niger

    Energy Technology Data Exchange (ETDEWEB)

    Rinker, Torri E.; Baker, Scott E.

    2007-01-29

    Citric acid production by the filamentous fungus Aspergillus niger is carried out in a process that causes the organism to drastically alter its morphology. This altered morphology includes hyphal swelling and highly limited polar growth resulting in clumps of swollen cells that eventually aggregate into pellets of approximately 100 microns in diameter. In this pelleted form, A. niger has increased citric acid production as compared to growth in filamentous form. Chitin is a crucial component of the cell wall of filamentous fungi. Alterations in the deposition or production of chitin may have profound effects on the morphology of the organism. In order to study the role of chitin synthesis in pellet formation we have deleted a chitin synthase gene (csmA) in Aspergillus niger strain ATCC 11414 using a PCR based deletion construct. This class of chitin synthases is only found in filamentous fungi and is not present in yeasts. The csmA genes contain a myosin motor domain at the N-terminus and a chitin synthesis domain at the C-terminus. They are believed to contribute to the specialized polar growth observed in filamentous fungi that is lacking in yeasts. The csmA deletion strain (csmAΔ) was subjected to minimal media with and without osmotic stabilizers as well as tested in citric acid production media. Without osmotic stabilizers, the mutant germlings were abnormally swollen, primarily in the subapical regions, and contained large vacuoles. However, this swelling is ultimately not inhibitory to growth as the germlings are able to recover and undergo polar growth. Colony formation was largely unaffected in the absence of osmotic stabilizers. In citric acid production media csmAΔ was observed to have a 2.5 fold increase in citric acid production. The controlled expression of this class of chitin synthases may be useful for improving production of organic acids in filamentous fungi.

  1. Extreme biomimetic approach for synthesis of nanocrystalline chitin-(Ti,Zr)O{sub 2} multiphase composites

    Energy Technology Data Exchange (ETDEWEB)

    Wysokowski, Marcin, E-mail: Marcin.Wysokowski@put.poznan.pl [Poznan University of Technology, Faculty of Chemical Technology, Institute of Chemical Technology and Engineering, Berdychowo 4, 60965, Poznan (Poland); Motylenko, Mykhaylo; Rafaja, David [TU Bergakademie Freiberg, Institute of Materials Science, Gustav-Zeuner-Str. 5, 09596, Freiberg (Germany); Koltsov, Iwona [Laboratory of Nanostructures, Institute of High Pressure Physics of The Polish Academy of Sciences, Sokołowska 29/37, 01-142, Warsaw (Poland); Stöcker, Hartmut [TU Bergakademie Freiberg, Institute of Experimental Physics, Leipziger str. 23, 09596, Freiberg (Germany); Szalaty, Tadeusz J. [Poznan University of Technology, Faculty of Chemical Technology, Institute of Chemical Technology and Engineering, Berdychowo 4, 60965, Poznan (Poland); Bazhenov, Vasilii V., E-mail: vasily.bazhenov@gmail.com [TU Bergakademie Freiberg, Institute of Experimental Physics, Leipziger str. 23, 09596, Freiberg (Germany); Stelling, Allison L. [Duke University, Department of Biochemistry, Durham, NC, 27708 (United States); Beyer, Jan; Heitmann, Johannes [TU Bergakademie Freiberg, Institute of Applied Physics, Leipziger str. 23, 09596, Freiberg (Germany); Jesionowski, Teofil [Poznan University of Technology, Faculty of Chemical Technology, Institute of Chemical Technology and Engineering, Berdychowo 4, 60965, Poznan (Poland); Petovic, Slavica; Đurović, Mirko [Institute of Marine Biology, Dobrota, 85330, Kotor (Montenegro); Ehrlich, Hermann [TU Bergakademie Freiberg, Institute of Experimental Physics, Leipziger str. 23, 09596, Freiberg (Germany)

    2017-02-15

    This work presents an extreme biomimetics route for the modification of the surface of fibre-based scaffolds of poriferan origin by the creation of novel nanostructured multiphase biocomposites. The exceptional thermal stability of the nanostructured sponge chitin allowed for the formation of a novel nanocrystalline chitin-(Ti,Zr)O{sub 2} composite with a well-defined nanoscale structure under hydrothermal conditions (160 °C). Using a combination of experimental techniques, including X-ray diffraction, scanning electron microscopy, high resolution transmission electron microscopy, EDX mapping and near-edge electron loss spectroscopy (ELNES) in TEM and thermogravimetry/differential scanning calorimetry coupled with mass spectrometry; we showed that this bioorganic scaffold facilitates selective crystallization of TiO{sub 2}, predominantly in form of anatase, over the monoclinic zirconium dioxide (baddeleyite). The control of the crystal morphology through the chitin templates is also demonstrated. Obtained samples were characterized in terms of their photoluminescent properties and photocatalytic performance. These data confirm the high potential of the extreme biomimetics approach for developing a new generation of multiphase biopolymer-based nanostructured materials. - Highlights: • Extreme biomimetically prepared chitin-(Ti,Zr)O{sub 2} and (Ti,Zr)O{sub 2} composites. • Chitin-(Ti,Zr)O{sub 2} composite contains anatase as the most inorganic component. • The mean crystallite size is (31.7 ± 0.3) nm for chitin-(Ti,Zr)O{sub 2} composite. • The mean crystallite size is (2.4 ± 0.5) nm for (Ti,Zr)O{sub 2} composite. • (Ti,Zr)O{sub 2} composite is 2 times more effective photocatalyst than chitin-(Ti,Zr)O{sub 2}.

  2. Extreme biomimetic approach for synthesis of nanocrystalline chitin-(Ti,Zr)O2 multiphase composites

    International Nuclear Information System (INIS)

    Wysokowski, Marcin; Motylenko, Mykhaylo; Rafaja, David; Koltsov, Iwona; Stöcker, Hartmut; Szalaty, Tadeusz J.; Bazhenov, Vasilii V.; Stelling, Allison L.; Beyer, Jan; Heitmann, Johannes; Jesionowski, Teofil; Petovic, Slavica; Đurović, Mirko; Ehrlich, Hermann

    2017-01-01

    This work presents an extreme biomimetics route for the modification of the surface of fibre-based scaffolds of poriferan origin by the creation of novel nanostructured multiphase biocomposites. The exceptional thermal stability of the nanostructured sponge chitin allowed for the formation of a novel nanocrystalline chitin-(Ti,Zr)O 2 composite with a well-defined nanoscale structure under hydrothermal conditions (160 °C). Using a combination of experimental techniques, including X-ray diffraction, scanning electron microscopy, high resolution transmission electron microscopy, EDX mapping and near-edge electron loss spectroscopy (ELNES) in TEM and thermogravimetry/differential scanning calorimetry coupled with mass spectrometry; we showed that this bioorganic scaffold facilitates selective crystallization of TiO 2 , predominantly in form of anatase, over the monoclinic zirconium dioxide (baddeleyite). The control of the crystal morphology through the chitin templates is also demonstrated. Obtained samples were characterized in terms of their photoluminescent properties and photocatalytic performance. These data confirm the high potential of the extreme biomimetics approach for developing a new generation of multiphase biopolymer-based nanostructured materials. - Highlights: • Extreme biomimetically prepared chitin-(Ti,Zr)O 2 and (Ti,Zr)O 2 composites. • Chitin-(Ti,Zr)O 2 composite contains anatase as the most inorganic component. • The mean crystallite size is (31.7 ± 0.3) nm for chitin-(Ti,Zr)O 2 composite. • The mean crystallite size is (2.4 ± 0.5) nm for (Ti,Zr)O 2 composite. • (Ti,Zr)O 2 composite is 2 times more effective photocatalyst than chitin-(Ti,Zr)O 2 .

  3. Synthesis and physicochemical characterization of chitin dihexanoate — A new biocompatible chitin derivative — In comparison to chitin dibutyrate

    Energy Technology Data Exchange (ETDEWEB)

    Skołucka-Szary, Karolina, E-mail: karolina.skolucka@celther.com [Department of Research and Development, Celther Poland Sp. z o.o. ul. Ostrzykowizna 14A, 05-170 Zakroczym (Poland); Ramięga, Aleksandra; Piaskowska, Wanda [Department of Research and Development, Celther Poland Sp. z o.o. ul. Ostrzykowizna 14A, 05-170 Zakroczym (Poland); Janicki, Bartosz [Silesian University of Technology, Faculty of Chemistry, Department of Physical Chemistry and Technology of Polymers, ul. M. Strzody 9, 44-100 Gliwice (Poland); Grala, Magdalena [Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, 90-363 Lodz (Poland); Rieske, Piotr [Department of Research and Development, Celther Poland Sp. z o.o. ul. Ostrzykowizna 14A, 05-170 Zakroczym (Poland); Bartczak, Zbigniew [Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, 90-363 Lodz (Poland); Piaskowski, Sylwester [Department of Research and Development, Celther Poland Sp. z o.o. ul. Ostrzykowizna 14A, 05-170 Zakroczym (Poland)

    2016-03-01

    Chitin dihexanoate (DHCH) is the novel biocompatible and technologically friendly highly substituted chitin diester. Here we described optimization of DHCH and chitin dibutyrate (dibutyryl chitin, DBC) synthesis conditions (temperature and reaction time) to obtain desired polymers with high reaction yield, high substitution degree (close to 2) and appropriately high molecular weights. A two-step procedure, employing acidic anhydrides (hexanoic or butyric anhydride) as the acylation agent and methanesulfonic acid both as the catalyst and the reaction medium, was applied. Chemical structures of DBC and DHCH were confirmed by NMR ({sup 1}H and {sup 13}C) and IR investigations. Mechanical properties, thermogravimetric analysis, differential scanning calorimetry and biocompatibility (Neutral red uptake assay, Skin Sensitization and Irritation Tests) were assessed. Both polymers proved highly biocompatible (non-cytotoxic in vitro, non-irritating and non-allergic to skin) and soluble in several organic solvents (dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, acetone, ethanol and others). It is worth emphasizing that DHCH and DBC can be easily processed by solvent casting method and the salt-leaching method, what gives the opportunity to prepare highly porous structures, which can be further successfully applied as the material for wound dressings and scaffolds for tissue engineering. - Highlights: • A new method for chitin dihexanoate (DHCH) synthesis was proposed. • DHCH physicochemical and biological properties were analyzed. • DHCH properties were compared with DBC characteristics. • For synthesis of both, DBC and DHCH methanesulfonic acid was used as the catalyst.

  4. 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.

  5. Comparative ultrastructure of the cuticle of trichostrongyle nematodes.

    Science.gov (United States)

    Beveridge, I; Durette-Desset, M C

    1994-09-01

    The ultrastructure of the cuticle was examined in Austrostrongylus victoriensis, Patricialina birdi and Woolleya monodelphis (Herpetostrongylidae) from marsupials, Paraustrostrongylus ratti (Herpetostrongylidae) from rodents, Nippostrongylus magnus and Odilia bainae (Heligmonellidae) from rodents, Cooperia oncophora and Camelostrongylus mentulatus (Trichostrongylidae) from ruminants, and Nematodirus spathiger (Molineidae) from ruminants. The principal cuticular layers described previously were present in all species investigated. Major differences in the shape and composition of cuticular struts were observed as well as differences in components of the median zone of the cuticle, including the fluid-filled regions present in several species. Several different types of strut were observed. Although strut structure within the Heligmonellidae appeared to be constant, there were variations within both the Herpetostrongylidae and Trichostrongylidae. In Nem. spathiger the cuticular ridges lacked struts. The diversity of structures found in the species examined suggests that more extensive comparative studies of the trichostrongyle cuticle are warranted.

  6. Extraction and characterization of chitin and chitosan from Nigerian ...

    African Journals Online (AJOL)

    Chitin was synthesized from Nigerian brown shrimps by a chemical process involving demineralization and deproteinisation. Deacetylation of the chitin was conducted to obtain Chitosan. The chitin and chitosan were characterized using FTIR, XRD and SEM. Proximate and elemental analysis were also conducted.

  7. 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.

  8. 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)

  9. The cuticle modulates ultraviolet reflectance of avian eggshells

    Directory of Open Access Journals (Sweden)

    Daphne C. Fecheyr-Lippens

    2015-07-01

    Full Text Available Avian eggshells are variedly coloured, yet only two pigments, biliverdin and protoporphyrin IX, are known to contribute to the dramatic diversity of their colours. By contrast, the contributions of structural or other chemical components of the eggshell are poorly understood. For example, unpigmented eggshells, which appear white to the human eye, vary in their ultraviolet (UV reflectance, which may be detectable by birds. We investigated the proximate mechanisms for the variation in UV-reflectance of unpigmented bird eggshells using spectrophotometry, electron microscopy, chemical analyses, and experimental manipulations. We specifically tested how UV-reflectance is affected by the eggshell cuticle, the outermost layer of most avian eggshells. The chemical dissolution of the outer eggshell layers, including the cuticle, increased UV-reflectance for only eggshells that contained a cuticle. Our findings demonstrate that the outer eggshell layers, including the cuticle, absorb UV-light, probably because they contain higher levels of organic components and other chemicals, such as calcium phosphates, compared to the predominantly calcite-based eggshell matrix. These data highlight the need to examine factors other than the known pigments in studies of avian eggshell colour.

  10. Cuticle scale measurement of animal fibers by SEM and AFM

    CSIR Research Space (South Africa)

    Notayi, M

    2013-12-01

    Full Text Available -1 51st Microscopy Society of Southern Africa (MSSA) Conference, Farm Inn, Pretoria, 3-6 December 2013 Cuticle scale measurement of animal fibers by SEM and AFM Notayi M, Engelbrechts JAA, Lee ME, Goosen WE, Hunter L and Botha AF Abstract...

  11. The extensible alloscutal cuticle of the tick, Ixodes ricinus

    DEFF Research Database (Denmark)

    Andersen, Svend Olav; Roepstorff, Peter

    2005-01-01

    The proteins in the distensible alloscutal cuticle of the blood-feeding tick, Ixodes ricinus, have been characterized by electrophoresis and chromatography, two of the proteins were purified and their total amino acid sequence determined. They show sequence similarity to cuticular proteins from t...

  12. Proteomic analysis of chicken eggshell cuticle membrane layer

    Czech Academy of Sciences Publication Activity Database

    Mikšík, Ivan; Ergang, Peter; Pácha, Jiří

    2014-01-01

    Roč. 406, č. 29 (2014), s. 7633-7640 ISSN 1618-2642 R&D Projects: GA ČR(CZ) GA13-17224S Institutional support: RVO:67985823 Keywords : mass spectrometry * bioanalyticalmethods * cuticle * chicken proteins * insoluble proteins * eggshell Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.436, year: 2014

  13. Ultrastructure, development, and homology of insect embryonic cuticles

    Czech Academy of Sciences Publication Activity Database

    Konopová, Barbora; Zrzavý, Jan

    2005-01-01

    Roč. 264, č. 3 (2005), s. 339-362 ISSN 0362-2525 R&D Projects: GA ČR(CZ) GD206/03/H034 Institutional research plan: CEZ:AV0Z50070508 Keywords : embryonic development * cuticle * metamorphosis Subject RIV: EA - Cell Biology Impact factor: 1.421, year: 2005

  14. Butterfly Wings Are Three-Dimensional: Pupal Cuticle Focal Spots and Their Associated Structures in Junonia Butterflies.

    Science.gov (United States)

    Taira, Wataru; Otaki, Joji M

    2016-01-01

    Butterfly wing color patterns often contain eyespots, which are developmentally determined at the late larval and early pupal stages by organizing activities of focal cells that can later form eyespot foci. In the pupal stage, the focal position of a future eyespot is often marked by a focal spot, one of the pupal cuticle spots, on the pupal surface. Here, we examined the possible relationships of the pupal focal spots with the underneath pupal wing tissues and with the adult wing eyespots using Junonia butterflies. Large pupal focal spots were found in two species with large adult eyespots, J. orithya and J. almana, whereas only small pupal focal spots were found in a species with small adult eyespots, J. hedonia. The size of five pupal focal spots on a single wing was correlated with the size of the corresponding adult eyespots in J. orithya. A pupal focal spot was a three-dimensional bulge of cuticle surface, and the underside of the major pupal focal spot exhibited a hollowed cuticle in a pupal case. Cross sections of a pupal wing revealed that the cuticle layer shows a curvature at a focal spot, and a positional correlation was observed between the cuticle layer thickness and its corresponding cell layer thickness. Adult major eyespots of J. orithya and J. almana exhibited surface elevations and depressions that approximately correspond to the coloration within an eyespot. Our results suggest that a pupal focal spot is produced by the organizing activity of focal cells underneath the focal spot. Probably because the focal cell layer immediately underneath a focal spot is thicker than that of its surrounding areas, eyespots of adult butterfly wings are three-dimensionally constructed. The color-height relationship in adult eyespots might have an implication in the developmental signaling for determining the eyespot color patterns.

  15. Butterfly Wings Are Three-Dimensional: Pupal Cuticle Focal Spots and Their Associated Structures in Junonia Butterflies.

    Directory of Open Access Journals (Sweden)

    Wataru Taira

    Full Text Available Butterfly wing color patterns often contain eyespots, which are developmentally determined at the late larval and early pupal stages by organizing activities of focal cells that can later form eyespot foci. In the pupal stage, the focal position of a future eyespot is often marked by a focal spot, one of the pupal cuticle spots, on the pupal surface. Here, we examined the possible relationships of the pupal focal spots with the underneath pupal wing tissues and with the adult wing eyespots using Junonia butterflies. Large pupal focal spots were found in two species with large adult eyespots, J. orithya and J. almana, whereas only small pupal focal spots were found in a species with small adult eyespots, J. hedonia. The size of five pupal focal spots on a single wing was correlated with the size of the corresponding adult eyespots in J. orithya. A pupal focal spot was a three-dimensional bulge of cuticle surface, and the underside of the major pupal focal spot exhibited a hollowed cuticle in a pupal case. Cross sections of a pupal wing revealed that the cuticle layer shows a curvature at a focal spot, and a positional correlation was observed between the cuticle layer thickness and its corresponding cell layer thickness. Adult major eyespots of J. orithya and J. almana exhibited surface elevations and depressions that approximately correspond to the coloration within an eyespot. Our results suggest that a pupal focal spot is produced by the organizing activity of focal cells underneath the focal spot. Probably because the focal cell layer immediately underneath a focal spot is thicker than that of its surrounding areas, eyespots of adult butterfly wings are three-dimensionally constructed. The color-height relationship in adult eyespots might have an implication in the developmental signaling for determining the eyespot color patterns.

  16. Fourier transform IR studies on the interaction of selected chemicals with isolated cuticles

    International Nuclear Information System (INIS)

    Luque, P.; Ramirez, F.J.; Heredia, A.; Bukovac, M.J.

    1994-01-01

    It is known that the plant cuticle represents the first barrier that must be overcome by any chemical reaching the plant surface from the atmosphere before entering the plant. Because of the importance of the cuticle as a barrier to penetration of a wide variety of compounds, its morphology, chemistry, and permeability have been extensively studied. However, only limited information is available on the nature of functional chemical groups present and their interaction and role during the penetration process. The usefulness of in situ Fourier transform infrared spectroscopy studies in identifying functional groups present in isolated cuticles is described and their relationships to the structure of the cuticular membrane are discussed. Applications of infrared spectroscopy on the presence and role of phenolics in the cuticle structure and during the cuticle development, nitrogen oxide binding to isolated cuticles, and the interactions between selected chemical probes during sorption by the cuticle are also described. (orig.)

  17. Experimental study of the microvascular architecture and bone formation when using a carboxymethyl-chitin for bone repair in extracted sockets

    International Nuclear Information System (INIS)

    Kinoshita, Tamotsu; Toda, Isumi; Ehara, Yuji; Nakanishi, Ko; Suwa, Fumihiko

    2011-01-01

    Chitin is an absorbable agent used to promote wound healing and hemostasis, and is also used in medical treatment. We investigated the effects of carboxymethyl-chitin (CM-chitin), a water-soluble derivative of chitin, on bone augmentation. Four maxillary incisors were extracted from 5 adult Crab-eating Macaques, then the extraction sockets on the subjects' right sides were immediately filled with CM-chitin (experimental sites), while the left sides were left unfilled (control). One, two, four, eight, and twelve weeks after the procedure, the animals were euthanized and acrylic resin was injected via the common carotid arteries. Bone-microvascular corrosion casts were made and observed using scanning electron microscopy to determine the volume ratio of newly-formed bone in each socket. After 1 week, newly-formed capillary networks were observed in the sockets of the experimental sites. After 2 weeks, the sockets in both the experimental and control sites were filled with newly-formed capillary networks. After 4 weeks, newly-formed bone was observed in the sockets of both sites and the sockets were also filled with newly-formed bone after 8 weeks. After 12 weeks, trabecular bone was thicker and more compressed than after 8 weeks. Image analysis showed that the volume ratio of newly-formed bone was not significantly different between the experimental and control sites. We concluded that CM-chitin does not obstruct bone augmentation in extracted tooth sockets and is useful to promote angiogenesis in the early stages. (author)

  18. Chitovibrin: a chitin-binding lectin from Vibrio parahemolyticus.

    Science.gov (United States)

    Gildemeister, O S; Zhu, B C; Laine, R A

    1994-12-01

    A novel 134 kDa, calcium-independent chitin-binding lectin, 'chitovibrin', is secreted by the marine bacterium Vibrio parahemolyticus, inducible with chitin or chitin-oligomers. Chitovibrin shows no apparent enzymatic activity but exhibits a strong affinity for chitin and chito-oligomers > dp9. The protein has an isoelectric pH of 3.6, shows thermal tolerance, binds chitin with an optimum at pH 6 and is active in 0-4 M NaCl. Chitovibrin appears to be completely different from other reported Vibrio lectins and may function to bind V. parahemolyticus to chitin substrates, or to capture or sequester chito-oligomers. It may be a member of a large group of recently described proteins in Vibrios related to a complex chitinoclastic (chitinivorous) system.

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

    Science.gov (United States)

    Badwan, Adnan A.; Rashid, Iyad; Al Omari, Mahmoud M.H.; Darras, Fouad H.

    2015-01-01

    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. PMID:25810109

  20. 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.

  1. Isolation and characterization of chitin and chitosan from marine origin.

    Science.gov (United States)

    Nwe, Nitar; Furuike, Tetsuya; Tamura, Hiroshi

    2014-01-01

    Nowadays, chitin and chitosan are produced from the shells of crabs and shrimps, and bone plate of squid in laboratory to industrial scale. Production of chitosan involved deproteinization, demineralization, and deacetylation. The characteristics of chitin and chitosan mainly depend on production processes and conditions. The characteristics of these biopolymers such as appearance of polymer, turbidity of polymer solution, degree of deacetylation, and molecular weight are of major importance on applications of these polymers. This chapter addresses the production processes and conditions to produce chitin, chitosan, and chito-oligosaccharide and methods for characterization of chitin, chitosan, and chito-oligosaccharide. © 2014 Elsevier Inc. All rights reserved.

  2. Simultaneous extraction of chitin and astaxanthin from waste of ...

    African Journals Online (AJOL)

    This work investigates simple methods for simultaneous extraction of astaxanthin and chitin from industrial waste of the South African West Coast rock lobster Jasus lalandii. Removal of proteins from waste is the critical step to yield intact chitin and astaxanthin. Because common chemical methods destroy astaxanthin and ...

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

    NARCIS (Netherlands)

    BEINTEMA, JJ

    1994-01-01

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

  4. 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

  5. Extraction and characterization of chitin and chitosan from ...

    African Journals Online (AJOL)

    Chitin has been extracted from two Tunisian crustacean species. The obtained chitin was transformed into the more useful soluble chitosan. These products were characterized by their biological activity as antimicrobial and antifungal properties. The tested bacterial strains were Escherichia coli American Type Cell Culture ...

  6. 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

  7. Gene expression and morphogenesis during the deposition of Drosophila wing cuticle.

    Science.gov (United States)

    Adler, Paul N

    2017-07-03

    The exoskeleton of insects and other arthropods is a very versatile material that is characterized by a complex multilayer structure. In Sobala and Adler (2016) we analyzed the process of wing cuticle deposition by RNAseq and electron microscopy. In this extra view we discuss the unique aspects of the envelope the first and most outermost layer and the gene expression program seen at the end of cuticle deposition. We discussed the role of undulae in the deposition of cuticle and how the hydrophobicity of wing cuticle arises.

  8. Obtention and characterization of chitin and chitosan from M. rosenbergii

    International Nuclear Information System (INIS)

    Battisti, Marcos V.; Campana Filho, Sergio P.

    2001-01-01

    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 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)

  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. Action on the Surface: Entomopathogenic Fungi versus the Insect Cuticle.

    Science.gov (United States)

    Ortiz-Urquiza, Almudena; Keyhani, Nemat O

    2013-07-16

    Infections mediated by broad host range entomopathogenic fungi represent seminal observations that led to one of the first germ theories of disease and are a classic example of a co-evolutionary arms race between a pathogen and target hosts. These fungi are able to parasitize susceptible hosts via direct penetration of the cuticle with the initial and potentially determining interaction occurring between the fungal spore and the insect epicuticle. Entomogenous fungi have evolved mechanisms for adhesion and recognition of host surface cues that help direct an adaptive response that includes the production of: (a) hydrolytic, assimilatory, and/or detoxifying enzymes including lipase/esterases, catalases, cytochrome P450s, proteases, and chitinases; (b) specialized infectious structures, e.g., appressoria or penetrant tubes; and (c) secondary and other metabolites that facilitate infection. Aside from immune responses, insects have evolved a number of mechanisms to keep pathogens at bay that include: (a) the production of (epi) cuticular antimicrobial lipids, proteins, and metabolites; (b) shedding of the cuticle during development; and (c) behavioral-environmental adaptations such as induced fever, burrowing, and grooming, as well as potentially enlisting the help of other microbes, all intended to stop the pathogen before it can breach the cuticle. Virulence and host-defense can be considered to be under constant reciprocal selective pressure, and the action on the surface likely contributes to phenomena such as strain variation, host range, and the increased virulence often noted once a (low) virulent strain is "passaged" through an insect host. Since the cuticle represents the first point of contact and barrier between the fungus and the insect, the "action on the surface" may represent the defining interactions that ultimately can lead either to successful mycosis by the pathogen or successful defense by the host. Knowledge concerning the molecular mechanisms

  11. Ultrasound stimulated release of gallic acid from chitin hydrogel matrix

    International Nuclear Information System (INIS)

    Jiang, Huixin; Kobayashi, Takaomi

    2017-01-01

    Ultrasound (US) stimulated drug release was examined in this study using a chitin hydrogel matrix loaded with gallic acid (GA), a drug used for wound healing and anticancer. Using phase inversion, GA-chitin hydrogels were prepared from chitin-dimethylacetamide (DMAc)/lithium chloride (LiCl) solution in the presence of GA, with 24 h exposure of the solution to water vapor. The GA release from the GA-chitin hydrogel was examined under different US powers of 0–30 W at 43 kHz. The effects of GA loading amounts in the hydrogels (0.54, 0.43, and 0.25 mg/cm 3 ) and chitin concentrations (0.1, 0.5, and 1 wt%) on the release behaviors were recorded under 43 kHz US exposure at 30 W. Results show that US accelerated the release efficiencies for all samples. Furthermore, the release efficiency increased concomitantly with increasing US power, GA loading amount, and decrease of the chitin concentration. The highest release rate of 0.74 μg/mL·min was obtained from 0.54 mg/cm 3 of GA-loaded hydrogel fabricated from a 0.1 wt% chitin mixture solution under 43 kHz US exposure at 30 W: nine times higher than that of the sample without US exposure. The hydrogel viscoelasticity demonstrated that the US irradiation rigidified the material. FT-IR showed that US can break the hydrogen bonds in the GA-chitin hydrogels. - Highlights: • Ultrasound (US) stimulated Gallic acid (GA) release from chitin hydrogel was studied. • The release efficiency of GA from chitin hydrogel increased nine times when irradiated by 43 kHz US compared with the sample without US. • Generalized 2D correlation and deconvolution study of FT-IR showed that US could promote the GA release by breaking hydrogen bonds.

  12. Ultrasound stimulated release of gallic acid from chitin hydrogel matrix

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Huixin; Kobayashi, Takaomi, E-mail: takaomi@nagaokaut.ac.jp

    2017-06-01

    Ultrasound (US) stimulated drug release was examined in this study using a chitin hydrogel matrix loaded with gallic acid (GA), a drug used for wound healing and anticancer. Using phase inversion, GA-chitin hydrogels were prepared from chitin-dimethylacetamide (DMAc)/lithium chloride (LiCl) solution in the presence of GA, with 24 h exposure of the solution to water vapor. The GA release from the GA-chitin hydrogel was examined under different US powers of 0–30 W at 43 kHz. The effects of GA loading amounts in the hydrogels (0.54, 0.43, and 0.25 mg/cm{sup 3}) and chitin concentrations (0.1, 0.5, and 1 wt%) on the release behaviors were recorded under 43 kHz US exposure at 30 W. Results show that US accelerated the release efficiencies for all samples. Furthermore, the release efficiency increased concomitantly with increasing US power, GA loading amount, and decrease of the chitin concentration. The highest release rate of 0.74 μg/mL·min was obtained from 0.54 mg/cm{sup 3} of GA-loaded hydrogel fabricated from a 0.1 wt% chitin mixture solution under 43 kHz US exposure at 30 W: nine times higher than that of the sample without US exposure. The hydrogel viscoelasticity demonstrated that the US irradiation rigidified the material. FT-IR showed that US can break the hydrogen bonds in the GA-chitin hydrogels. - Highlights: • Ultrasound (US) stimulated Gallic acid (GA) release from chitin hydrogel was studied. • The release efficiency of GA from chitin hydrogel increased nine times when irradiated by 43 kHz US compared with the sample without US. • Generalized 2D correlation and deconvolution study of FT-IR showed that US could promote the GA release by breaking hydrogen bonds.

  13. Preparation of Chitin, Study of Physicochemical Properties and Biopesticide Activities

    Directory of Open Access Journals (Sweden)

    Yuli Rohyami

    2013-08-01

    Full Text Available Chitin was preparated from shrimp shells by chemically method. Preparation was carried out by deproteination shrimp shells powder < 150 mesh with 1 - 2 M NaOH, demineralization followed by reaction with 1.0 M HCl and depigmentation with (1 : 2 : 4, v/v of chloroform : methanol : water. Physicochemical properties of chitin was determined from characterization of infrared spectra, ash value, loss on drying and total of nitrogen. Biopesticide activities of chitin was done to pest Bemisia tabaci at guava leaves with various concentration from 0.5 to 2.0 % chitin on 3 % v/v acetic acid. This study indicated that concentration of NaOH on deproteination process effected to its physicochemicals properties. Effectivity of 2 M NaOH on deproteination reaction was higher than 1 M NaOH . The degree of chitin deacetylation from 2 M NaOH was 13.61% and had lower molar ratio of total nitrogen. The degree of deacetylation of chitin from 1 M NaOH had lower and had higher molar ratio of total nitrogen. Physicochemicals properties of chitin quite an impact on its ability to reduce pest Bemisia tabaci. Biopesticide activity assay showed that treatment for 2 days on average mortality rate of 13.83%. Deacetylation of chitin which has a higher degree have a greaterability biopesticide with a mortality rate of up to 38.24%. This study the effect of deproteination process to biopesticide activities of chitin.Key Words : chitin, degree of deacetilation, molar ratio, biopesticide, Bemisia tabaci

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

    Science.gov (United States)

    Chitin-binding proteins (CBPs) existed in various species and involved in different biology processes. In the present study, we cloned a full length cDNA of chitin-binding protein-like (PpCBP-like) from Pteromalus puparum, a pupal endoparasitoid of Pieris rapae. PpCBP-like encoded a 96 putative amin...

  15. 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.

  16. Preparation and characterization of α-chitin from cicada sloughs

    International Nuclear Information System (INIS)

    Sajomsang, Warayuth; Gonil, Pattarapond

    2010-01-01

    In this study, a new source of insect chitin was proposed. Insect chitin was extracted from cicada sloughs by 1 M HCl and 1 M NaOH treatment for demineralization and deproteinization, respectively. The brown color of this chitin from cicada sloughs was removed using 6% sodium hypochlorite as an oxidizing agent. It was found that the insect chitin extracted from the cicada sloughs has a higher percent recovery than the chitin from rice-field crab shells. The chemical structure and physicochemical properties of α-chitin from cicada sloughs were characterized using elemental analysis (EA), attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), proton nuclear magnetic resonance spectroscopy ( 1 H NMR), solid-state 13 C cross-polarization magic-angle-spinning nuclear magnetic resonance (CP/MAS) NMR spectroscopy, X-ray diffractometry (XRD), and thermogravimetry (TG). The degree of acetylation (DA) was determined by EA, 1 H NMR, and 13 C CP/MAS NMR techniques. The DA values of chitin from cicada sloughs were in the range of 97% to 102% depending on each technique. Furthermore, it was found that the DA increased with an increasing thermal property and crystallinity.

  17. Wastewater treatment with ion-exchange chitin membrane

    International Nuclear Information System (INIS)

    Paulenova, A.; Fjeld, R. A.; Visacky, V.

    2001-01-01

    Chitin, poly(N-acetyl-D glucosamine) and chitosan, its deacetylated derivates have recently obtained attention as bio-sorbents, because they shown a great ability to accumulate heavy metals and other pollutants. It was found that recovery of metals is strongly affected by pH. At low acidic pH range 4-5 chitin membrane exhibits better selectivity for lead than for cadmium or zinc. Sorption preference for metals decreases in the order: Pb > Cd > Zn. For uranium, as well for strontium was observed significant increase of recovery at decrease of pH to slightly acidic, close to neutral value. It was shown that chemical behavior of chitin membrane is excellent; ion-exchange nature of chitin was not changed during chitin membrane manufacturing process. Using of chitin membrane instead of chitin flake column brings significant increasing of driving force of the separation process, limited in the case of column experimental design by diffusion coefficient, while in the case of membrane process only by mass transfer coefficient. (authors)

  18. Fruit cuticle lipid composition and water loss in a diverse collection of pepper (capsicum)

    Science.gov (United States)

    Pepper (Capsicum spp.) fruits are covered by a relatively thick coating of cuticle that limits fruit water loss, a trait previously associated with maintenance of post-harvest fruit quality during commercial marketing. We’ve examined the fruit cuticles from 50 diverse pepper genotypes from a world c...

  19. 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.

  20. Characterization of FIBCD1 as an acetyl group-binding receptor that binds chitin

    DEFF Research Database (Denmark)

    Schlosser, Anders; Thomsen, Theresa; Moeller, Jesper B

    2009-01-01

    Chitin is a highly acetylated compound and the second most abundant biopolymer in the world next to cellulose. Vertebrates are exposed to chitin both through food ingestion and when infected with parasites, and fungi and chitin modulate the immune response in different directions. We have...... fragments. FIBCD1 may play an important role in controlling the exposure of intestine to chitin and chitin fragments, which is of great relevance for the immune defense against parasites and fungi and for immune response modulation....

  1. Cuticle thickening associated with pyrethroid resistance in the major malaria vector Anopheles funestus

    Directory of Open Access Journals (Sweden)

    Coetzee M

    2010-08-01

    Full Text Available Abstract Background Malaria in South Africa is primarily transmitted by Anopheles funestus Giles. Resistance to pyrethroid insecticides in An. funestus in northern Kwazulu/Natal, South Africa, and in neighbouring areas of southern Mozambique enabled populations of this species to increase their ranges into areas where pyrethroids were being exclusively used for malaria control. Pyrethroid resistance in southern African An. funestus is primarily conferred by monooxygenase enzyme metabolism. However, selection for this resistance mechanism is likely to have occurred in conjunction with other factors that improve production of the resistance phenotype. A strong candidate is cuticle thickening. This is because thicker cuticles lead to slower rates of insecticide absorption, which is likely to increase the efficiency of metabolic detoxification. Results Measures of mean cuticle thickness in laboratory samples of female An. funestus were obtained using scanning electron microscopy (SEM. These females were drawn from a laboratory colony carrying the pyrethroid resistance phenotype at a stable rate, but not fixed. Prior to cuticle thickness measurements, these samples were characterised as either more or less tolerant to permethrin exposure in one experiment, and either permethrin resistant or susceptible in another experiment. There was a significant and positive correlation between mean cuticle thickness and time to knock down during exposure to permethrin. Mean cuticle thickness was significantly greater in those samples characterised either as more tolerant or resistant to permethrin exposure compared to those characterised as either less tolerant or permethrin susceptible. Further, insecticide susceptible female An. funestus have thicker cuticles than their male counterparts. Conclusion Pyrethroid tolerant or resistant An. funestus females are likely to have thicker cuticles than less tolerant or susceptible females, and females generally have

  2. Effect of egg washing on the cuticle quality of brown and white table eggs.

    Science.gov (United States)

    Leleu, S; Messens, W; De Reu, K; De Preter, S; Herman, L; Heyndrickx, M; De Baerdemaeker, J; Michiels, C W; Bain, M

    2011-10-01

    Egg washing is currently not permitted within the European Union, with few exceptions. This is mainly because there are concerns that cuticle damage could occur during or after the washing process, as a result of a suboptimal operation. In this study, the cuticle coverage levels of 400 washed or unwashed eggs, derived from either a brown or a white egg-laying flock at the end of lay, were compared. The eggs from older hens inherently have poorer cuticle coverage and as a result arguably constitute a greater risk to consumer safety if they are then washed. Thus, the effects of the washing procedure used in this study on cuticle quality were tested under the worst-case scenario. A standard Swedish egg washing process was used. The cuticle coverage of the eggs was assessed by a colorimeter by quantifying the color difference before and after staining with Tartrazine and Green S. The cuticle of an additional 30 eggs from each of the four groups was then visually assessed by scanning electron microscopy. The staining characteristics of the cuticle varied greatly within each group of eggs and showed that the washing process did not lead to cuticle damage. Scanning electron microscopy confirmed that there was no irreversible damage to the cuticle of the washed eggs and that it was not possible to correctly assign the treatment (washed or not) based on a visual assessment. In conclusion, no evidence could be found to suggest that the washing procedure used in this investigation irreversibly changed the quality of the cuticle.

  3. Effects from additives on deacetylation of chitin

    International Nuclear Information System (INIS)

    Campana Filho, Sergio P.; Signini, Roberta

    2001-01-01

    Deacetylation reactions of commercial chitin were carried out in aqueous sodium hydroxide solution at 115 deg C for 6 hours. The effect from additives (sodium borohydride or anthraquinone) and of bubbling inert gas (nitrogen or argon) on the characteristics of deacetylated samples were evaluated. Average degrees of acetylation and intrinsic viscosity were determined by 1 H NMR spectroscopy and capillary viscometry, respectively. X-ray diffraction was employed to evaluate changes in crystallinity and infrared spectroscopy was used to monitor structural changes due to deacetylation. The bubbling of inert gas during the deacetylation reaction resulted in more crystalline samples of chitosan. Deacetylation carried out without any additive produced slightly more deacetylated chitosan but they were severely depolymerized. The depolymerization process was much less important when sodium borohydride was added to the reaction medium but the addition of anthraquinone and the bubbling of nitrogen, or argon, did not have any effect, this suggests that oxygen is not required for depolymerization. (author)

  4. Detection of irradiation in cuticles of commercial shrimps

    International Nuclear Information System (INIS)

    Lehner, K.; Stachowicz, W.

    2006-01-01

    Laboratory for Detection of Irradiated Food has more and more orders for detection of irradiation in shrimps. A method adapted to achieve detection of irradiation in this material is a thermoluminescence measure. However, the procedure is time-consuming - needs several days to receive the result. The aim of presented study was to elaborate the EPR examination of the possible irradiation in this product. As a result od the performed studies it can be concluded, that the EPR measurement of cuticles of shrimps can be adapted as the preliminary, screening test proving the irradiation of shrimp. It has to be stressed, however, that the lack of a specific, hydroxyapatite born EPR signal in the spectrum cannot suggest that sample was not irradiated

  5. Comparison of green method for chitin deacetylation

    Science.gov (United States)

    Anwar, Muslih; Anggraeni, Ayu Septi; Amin, M. Harisuddin Al

    2017-03-01

    Developing highly environmentally friendly and cost-effective approaches for the chitosan production has paramount important in the future technology. Deacetylation process is one of the most importing steps to classify the quality of chitosan. This research aimed to study the best method for deacetylation of chitin considered by several factors like the concentration of base, temperature, time and reaction method. From the green chemistry point of view, conventional refluxing method relatively wasted energy compared to another method such as maceration, grinding and sonication. The degree of deacetylation (DD) of chitosan was studied by sonication, resulted in slightly increasing of DD from 73.14 to 73.28% during the time from 0.5 h to 1 h. Deacetylation of chitin with various sodium hydroxide concentration 60, 70 and 80% gave 73.14, 76.36 and 77.88% of DD, respectively. Variation of temperature at 40, 60, and 80 °C was slightly affected on increasing DD from 67.53, 72.84 and 73.14%, respectively. The DD of chitosan significantly increased from 60.19, 74.27 and 81.20% respectively correspondent to varying NaOH concentration 60, 70 and 80% using the maceration method. Solid phase grinding method for half hour resulted in 79.49% of DD. The application of ultrasound grinding method not only was enhanced toward the deacetylation but also favoured the depolymerization process. Moreover, maceration for 7 days with 80% NaOH can be as an alternative method.

  6. 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.

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

    Directory of Open Access Journals (Sweden)

    Nidal Daraghmeh

    2015-03-01

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

  8. Environmental scanning electron microscopy analysis of Proteus mirabilis biofilms grown on chitin and stainless steel.

    Science.gov (United States)

    Fernández-Delgado, Milagro; Duque, Zoilabet; Rojas, Héctor; Suárez, Paula; Contreras, Monica; García-Amado, María A; Alciaturi, Carlos

    Proteus mirabilis is a human pathogen able to form biofilms on the surface of urinary catheters. Little is known about P. mirabilis biofilms on natural or industrial surfaces and the potential consequences for these settings. The main aim of this work was to assess and compare the adhesion and biofilm formation of P. mirabilis strains from different origins on chitin and stainless steel surfaces within 4 to 96 h. Using environmental scanning electron microscopy, the biofilms of a clinical strain grown on chitin at 4 h showed greater adhesion, aggregation, thickness, and extracellular matrix production than those grown on stainless steel, whereas biofilms of an environmental strain had less aggregation on both surfaces. Biofilms of both P. mirabilis strains developed different structures on chitin, such as pillars, mushrooms, channels, and crystalline-like precipitates between 24 and 96 h, in contrast with flat-layer biofilms produced on stainless steel. Significant differences ( p  biofilm formation. This represents the first study of P. mirabilis showing adhesion, biofilm formation, and development of different structures on surfaces found outside the human host.

  9. 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

    2012-01-07

    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.

  10. Removal of hazardous dye Ponceau-S by using Chitin:

    African Journals Online (AJOL)

    Sr030111Bin Comp

    Key words: Chitin, Ponceau-S, organic bioadsorbent, colored organic, industrial effluents. ..... of cationic azo dye by TiO2/bentonite nanocomposite, J. Photochem. ... effluents to freshwater and estuarine algae, crustaceans and fishes. Environ.

  11. Preparation of Chitin-PLA laminated composite for implantable application

    Directory of Open Access Journals (Sweden)

    Romana Nasrin

    2017-12-01

    Full Text Available The present study explores the possibilities of using locally available inexpensive waste prawn shell derived chitin reinforced and bioabsorbable polylactic acid (PLA laminated composites to develop new materials with excellent mechanical and thermal properties for implantable application such as in bone or dental implant. Chitin at different concentration (1–20% of PLA reinforced PLA films (CTP were fabricated by solvent casting process and laminated chitin-PLA composites (LCTP were prepared by laminating PLA film (obtained by hot press method with CTP also by hot press method at 160 °C. The effect of variation of chitin concentration on the resulting laminated composite's behavior was investigated. The detailed physico-mechanical, surface morphology and thermal were assessed with different characterization technique such as FT-IR, XRD, SEM and TGA. The FTIR spectra showed the characteristic peaks for chitin and PLA in the composites. SEM images showed an excellent dispersion of chitin in the films and composites. Thermogravimetric analysis (TGA showed that the complete degradation of chitin, PLA film, 5% chitin reinforced PLA film (CTP2 and LCTP are 98%, 95%, 87% and 98% respectively at temperature of 500 °C. The tensile strength of the LCTP was found 25.09 MPa which is significantly higher than pure PLA film (18.55 MPa and CTP2 film (8.83 MPa. After lamination of pure PLA and CTP2 film, the composite (LCTP yielded 0.265–1.061% water absorption from 30 min to 24 h immerse in water that is much lower than PLA and CTP. The increased mechanical properties of the laminated films with the increase of chitin content indicated good dispersion of chitin into PLA and strong interfacial actions between the polymer and chitin. The improvement of mechanical properties and the results of antimicrobial and cytotoxicity of the composites also evaluated and revealed the composite would be a suitable candidate for implant application in biomedical

  12. Preparation of Chitin-PLA laminated composite for implantable application.

    Science.gov (United States)

    Nasrin, Romana; Biswas, Shanta; Rashid, Taslim Ur; Afrin, Sanjida; Jahan, Rumana Akhter; Haque, Papia; Rahman, Mohammed Mizanur

    2017-12-01

    The present study explores the possibilities of using locally available inexpensive waste prawn shell derived chitin reinforced and bioabsorbable polylactic acid (PLA) laminated composites to develop new materials with excellent mechanical and thermal properties for implantable application such as in bone or dental implant. Chitin at different concentration (1-20% of PLA) reinforced PLA films (CTP) were fabricated by solvent casting process and laminated chitin-PLA composites (LCTP) were prepared by laminating PLA film (obtained by hot press method) with CTP also by hot press method at 160 °C. The effect of variation of chitin concentration on the resulting laminated composite's behavior was investigated. The detailed physico-mechanical, surface morphology and thermal were assessed with different characterization technique such as FT-IR, XRD, SEM and TGA. The FTIR spectra showed the characteristic peaks for chitin and PLA in the composites. SEM images showed an excellent dispersion of chitin in the films and composites. Thermogravimetric analysis (TGA) showed that the complete degradation of chitin, PLA film, 5% chitin reinforced PLA film (CTP2) and LCTP are 98%, 95%, 87% and 98% respectively at temperature of 500 °C. The tensile strength of the LCTP was found 25.09 MPa which is significantly higher than pure PLA film (18.55 MPa) and CTP2 film (8.83 MPa). After lamination of pure PLA and CTP2 film, the composite (LCTP) yielded 0.265-1.061% water absorption from 30 min to 24 h immerse in water that is much lower than PLA and CTP. The increased mechanical properties of the laminated films with the increase of chitin content indicated good dispersion of chitin into PLA and strong interfacial actions between the polymer and chitin. The improvement of mechanical properties and the results of antimicrobial and cytotoxicity of the composites also evaluated and revealed the composite would be a suitable candidate for implant application in biomedical sector.

  13. Chitin Lengthens Power Production in a Sedimentary Microbial Fuel Cell

    Science.gov (United States)

    2014-01-01

    organic carbon sediments demonstrate that chitin enhances and lengthens power production. Keywords—chitin; MFC; microbiology ; iron-reducing bacteria...levels of organic content available as a food source for bacteria in the sediment. Dependent upon applications, there are scenarios where a SMFC...as ethanol, molasses, or vegetable oils. In the case of underwater marine sediment, options for carbon amendment are limited to solid carbon

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

    International Nuclear Information System (INIS)

    Hoschka, L.

    1982-01-01

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

  15. 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.

  16. Dehydration protection provided by a maternal cuticle improves offspring fitness in the moss Funaria hygrometrica.

    Science.gov (United States)

    Budke, Jessica M; Goffinet, Bernard; Jones, Cynthia S

    2013-05-01

    In bryophytes the sporophyte offspring are in contact with, nourished from, and partially surrounded by the maternal gametophyte throughout their lifespan. During early development, the moss sporophyte is covered by the calyptra, a cap of maternal gametophyte tissue that has a multilayered cuticle. In this study the effects on sporophyte offspring fitness of removing the maternal calyptra cuticle, in combination with dehydration stress, is experimentally determined. Using the moss Funaria hygrometrica, calyptra cuticle waxes were removed by chemical extraction and individuals were exposed to a short-term dehydration event. Sporophytes were returned to high humidity to complete development and then aspects of sporophyte survival, development, functional morphology, and reproductive output were measured. It was found that removal of calyptra cuticle under low humidity results in significant negative impacts to moss sporophyte fitness, resulting in decreased survival, increased tissue damage, incomplete sporophyte development, more peristome malformations, and decreased reproductive output. This study represents the strongest evidence to date that the structure of the calyptra cuticle functions in dehydration protection of the immature moss sporophyte. The investment in a maternal calyptra with a multilayered cuticle increases offspring fitness and provides a functional explanation for calyptra retention across mosses. The moss calyptra may represent the earliest occurance of maternal protection via structural provisioning of a cuticle in green plants.

  17. Absorption of UV-B to blue light radiation by leaf cuticles of selected crop plants

    International Nuclear Information System (INIS)

    Baur, P.; Stulle, K.; Schönherr, J.; Uhlig, B.

    1998-01-01

    Plants have protective pigments absorbing destructive shortwave radiation. These pigments have been found in the epidermis and mesophyll of leaves. We studied the absorption characteristics of the leaf cuticle, the outermost part of the epidermis that is directly exposed to radiation. Adaxial leaf cuticles of apple, pear, sour cherry, strawberry, cauliflower, sugarbeet, and 13 other plant species were tested. The UV-B absorption was highest in Citrus aurantium and Citrus maxima (<3 % transmittance) and lowest in sugarbeet and peach (>64 % transmittance). The absorption maxima are at wavelenghts below 320 nm. Significant absorption was also determined at 500 nm, which correlated with cuticle thickness of the plant species (r(2)=0.72). The absorption in the range of 250 to 350 nm is caused by pigments with a high extinction coefficient. This absorption is species dependent and the patterns were designated to three different types. The highest absorption was found in evergreen species. The extraction of cuticular waxes had little effect on absorption. The specific absorption of shortwave radiation by plant cuticles is probably caused by pigments covalently bound to cut in. It is known for some plant species that cuticles can contain the phenolics p-coumaric acid, ferulic acid, and vanillic acid. Mixtures of these phenolics had spectra similar to cuticles. For most species absorption of shortwave radiation by the cuticle alone does not give complete protection

  18. Squid pen-inspired chitinous functional materials: Hierarchical chitin fibers by centrifugal jet-spinning and transparent chitin fiber-reinforced composite

    Science.gov (United States)

    Jeong, Seung-Hwan; Kim, Joong-Kwon; Lim, Young-Woo; Hwang, Hyun-Bin; Kwon, Hee-Young; Bae, Byeong-Soo; Jin, Jungho

    2018-01-01

    Here, inspired by the fibrous composite structure of a squid pen, we introduce hierarchical chitin fibers (herein, termed "Chiber") and their transparent composites and demonstrate the potential of these chitinous functional materials as a sustainable separation-membrane and reinforcing filler for composites. We employ a centrifugal jet-spinning process to fabricate Chiber with aligned chitin nanofibrillar architectures, for which we discuss the processing-morphology relationship. A nonwoven fiber-mat made of Chiber exhibits excellent adsorbing performance for a toxic ionic dye (Congo Red), and has a low coefficient of thermal expansion comparable to that of glass fibers. Finally, we demonstrate a squid pen-mimetic transparent composite using Chiber and investigate its optical property.

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

    Directory of Open Access Journals (Sweden)

    Feng Zhu

    2012-04-01

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

  20. A permeable cuticle is associated with the release of reactive oxygen species and induction of innate immunity.

    Directory of Open Access Journals (Sweden)

    Floriane L'Haridon

    2011-07-01

    Full Text Available Wounded leaves of Arabidopsis thaliana show transient immunity to Botrytis cinerea, the causal agent of grey mould. Using a fluorescent probe, histological staining and a luminol assay, we now show that reactive oxygen species (ROS, including H(2O(2 and O(2 (-, are produced within minutes after wounding. ROS are formed in the absence of the enzymes Atrboh D and F and can be prevented by diphenylene iodonium (DPI or catalase. H(2O(2 was shown to protect plants upon exogenous application. ROS accumulation and resistance to B. cinerea were abolished when wounded leaves were incubated under dry conditions, an effect that was found to depend on abscisic acid (ABA. Accordingly, ABA biosynthesis mutants (aba2 and aba3 were still fully resistant under dry conditions even without wounding. Under dry conditions, wounded plants contained higher ABA levels and displayed enhanced expression of ABA-dependent and ABA-reporter genes. Mutants impaired in cutin synthesis such as bdg and lacs2.3 are already known to display a high level of resistance to B. cinerea and were found to produce ROS even when leaves were not wounded. An increased permeability of the cuticle and enhanced ROS production were detected in aba2 and aba3 mutants as described for bdg and lacs2.3. Moreover, leaf surfaces treated with cutinase produced ROS and became more protected to B. cinerea. Thus, increased permeability of the cuticle is strongly linked with ROS formation and resistance to B. cinerea. The amount of oxalic acid, an inhibitor of ROS secreted by B. cinerea could be reduced using plants over expressing a fungal oxalate decarboxylase of Trametes versicolor. Infection of such plants resulted in a faster ROS accumulation and resistance to B. cinerea than that observed in untransformed controls, demonstrating the importance of fungal suppression of ROS formation by oxalic acid. Thus, changes in the diffusive properties of the cuticle are linked with the induction ROS and attending

  1. Effects of wind and simulated acid mist on leaf cuticles

    International Nuclear Information System (INIS)

    Hoad, S.P.; Jeffree, C.E.; Grace, J.

    1994-01-01

    The combined effect of wind and simulated acid mist on leaf cuticles was investigated in beech (Fagus sylvatica L.) and birch (Betula pubescens Ehr.). Macroscopic and microscopic features of wind damage are described. Visibly damaged leaf area and the numbers of microscopic cuticular lesions were measured. The cuticular conductance to water vapour (g c ) of the astomatous adaxial surfaces of the leaves was measured by a gravimetric method. Field experimenntal sites were selected to provide either: 1. Direct wind action on widely-spaced plants caused by high speed and impaction of wind-blown particles, but with minimal mutual leaf abrasion 2. Indirect wind action via a high degree of mutual abrasion between closely-spaced plants. Direct wind action increased water loss via the leaf adaxial cuticle two- to three-fold in each species, by increasing the numbers of microscopic cuticular lesions. Indirect wind action caused more visible damage to leaves than direct wind action, increased g c by about threefold compared with complete shelter, and induced the most cuticular lesions. Acid mists at pH 3 or pH 5 were applied to the plants in situ at weekly intervals over a 100-day period. In sheltered plants, no effect of acid mist was detected on visibly damaged leaf area, the numbers of microscopic cuticular lesions, or on g c . However, acid mists in combination with wind exposure caused significant effects on cuticular integrity that were dependent on the type of wind action. Direct wind action combined with pH 3 acid mist resulted in the largest numbers of microscopic cuticular lesions, and the highest g c . By contrast, indirect wind action combined with pH 3 acid mist caused most visible damage to leaf tissue, but fewer microscopic lesions, and lower g c , than in plants treated with water mist. In severely-abraded leaves exposed to indirect wind action and low-pH acid rain, g c may be reduced by wound-isolation of blocks of non-functional leaf tissue. (orig.)

  2. Phytochemistry of the fossilized-cuticle frond Macroneuropteris macrophylla (Pennsylvanian seed fern, Canada)

    Energy Technology Data Exchange (ETDEWEB)

    Zodrow, Erwin L. [Palaeobotanical Laboratory, Cape Breton University, Sydney, Nova Scotia, B1P 6L2 (Canada); D' Angelo, Jose A. [IANIGLA, CCT-CONICET-Mendoza, Avda. Ruiz Leal s/n Parque Gral. San Martin (5500) Mendoza (Argentina); Mastalerz, Maria [Indiana Geological Survey, Indiana University, Bloomington, IN, 47405-2208 (United States); Cleal, Christopher J. [Department of Biodiversity and Systematic Biology, National Museum of Wales, Cathays Park, Cardiff, CF10 3NP (United Kingdom); Keefe, Dale [Molecular Spectroscopy Research Laboratory, Department of Chemistry, Cape Breton University, Sydney, Nova Scotia (Canada)

    2010-11-01

    In Canada's Sydney Coalfield, specimens of the extinct Carboniferous seed fern Macroneuropteris macrophylla (Brongniart) invariably show preservation stages intermediate between compression and fossilized-cuticle, even concerning a single pinnule. In this interdisciplinary approach, we study a ca. 300 to 350 mm long fossilized-cuticle-preserved frond section of M. macrophylla (Brongniart) that represents about one third of the length of a frond that was originally 1 m long. Size and preservation allow us to study the phytochemistry of the cuticle biomacropolymers over the length of the frond to assess what impact, if any, results would have on Carboniferous palaeophytochemotaxonomy. For comparison, the phytochemistry of compressions with their extracted cuticles from the same species and the same sample locality is also investigated. We use solid- and liquid-state, semi-quantitative Fourier transform infrared spectroscopy (FTIR) for the chemical characterization of the frond. Based on our results, we infer an essentially uniform phytochemistry over the fossilized-cuticle frond, suggesting that only a single pinnule needs to be analyzed to get an overall phytochemical picture of the frond, which has been our long-time working hypothesis. We distinguish between phytochemistry and cutinization. The latter is much less pronounced above than below the frond dichotomy, and we suggest a palaeoecological cause, rather than differing pathways of organic matter transformation. Moreover, cuticles below and above the frond dichotomy have essentially the same epidermal pattern, but those from below have features that may have been an adaptation to prevent stomatal flooding during the tropical, rainy season. This study suggests that chemically the fossilized-cuticle is more similar to the compression than to the cuticle obtained from that compression of the same species which invites reevaluation of the classical compression concept. (author)

  3. Phytochemistry of the fossilized-cuticle frond Macroneuropteris macrophylla (Pennsylvanian seed fern, Canada)

    Science.gov (United States)

    Zodrow, E.L.; D'Angelo, J. A.; Mastalerz, Maria; Cleal, C.J.; Keefe, D.

    2010-01-01

    In Canada's Sydney Coalfield, specimens of the extinct Carboniferous seed fern Macroneuropteris macrophylla (Brongniart) invariably show preservation stages intermediate between compression and fossilized-cuticle, even concerning a single pinnule. In this interdisciplinary approach, we study a ca. 300 to 350 mm long fossilized-cuticle-preserved frond section of M. macrophylla (Brongniart) that represents about one third of the length of a frond that was originally 1 m long. Size and preservation allow us to study the phytochemistry of the cuticle biomacropolymers over the length of the frond to assess what impact, if any, results would have on Carboniferous palaeophytochemotaxonomy. For comparison, the phytochemistry of compressions with their extracted cuticles from the same species and the same sample locality is also investigated. We use solid- and liquid-state, semi-quantitative Fourier transform infrared spectroscopy (FTIR) for the chemical characterization of the frond.Based on our results, we infer an essentially uniform phytochemistry over the fossilized-cuticle frond, suggesting that only a single pinnule needs to be analyzed to get an overall phytochemical picture of the frond, which has been our long-time working hypothesis. We distinguish between phytochemistry and cutinization. The latter is much less pronounced above than below the frond dichotomy, and we suggest a palaeoecological cause, rather than differing pathways of organic matter transformation. Moreover, cuticles below and above the frond dichotomy have essentially the same epidermal pattern, but those from below have features that may have been an adaptation to prevent stomatal flooding during the tropical, rainy season.This study suggests that chemically the fossilized-cuticle is more similar to the compression than to the cuticle obtained from that compression of the same species which invites reevaluation of the classical compression concept. ?? 2010 Elsevier B.V.

  4. Monitoring agrochemical diffusion through cuticle wax with coherent Raman scattering

    Science.gov (United States)

    Gaunt, Nicholas P.; Thomson, Niall; Padia, Faheem; Moger, Julian

    2018-02-01

    The world's population is increasing rapidly and higher calorific diets are becoming more common; as a consequence the demand for grain is predicted to increase by more than 50% by 2050 without a significant increase in the available agricultural land. Maximising the productivity of the existing agricultural land is key to maintaining food security and agrochemicals continue to be a key enabler for the efficiency gains required. However, agrochemicals can be susceptible to significant losses and thus often require further chemical to be applied to compensate. Sources of such losses include spray drift, poor spray retention/capture by the target and poor penetration through the plant cuticle. Adjuvants can be used to help mitigate such losses but characterising how they alter the movement of the active ingredients (AIs) can be challenging. In this contribution we demonstrate the use of coherent Raman Scattering (CRS) as a tool to enable in-situ, real-time, label free characterisation of agrochemical AI as they move through wax.

  5. The evolution of eggshell cuticle in relation to nesting ecology

    Science.gov (United States)

    Hauber, Mark E.

    2016-01-01

    Avian eggs are at risk of microbial infection prior to and during incubation. A large number of defence mechanisms have evolved in response to the severe costs imposed by these infections. The eggshell's cuticle is an important component of antimicrobial defence, and its role in preventing contamination by microorganisms in domestic chickens is well known. Nanometer-scale cuticular spheres that reduce microbial attachment and penetration have recently been identified on eggs of several wild avian species. However, whether these spheres have evolved specifically for antimicrobial defence is unknown. Here, we use comparative data on eggshell cuticular structure and nesting ecology to test the hypothesis that birds nesting in habitats with higher risk of infection (e.g. wetter and warmer) are more likely to evolve cuticular nanospheres on their eggshells than those nesting in less risky habitats. We found that nanostructuring, present in 54 of 296 analysed species, is the ancestral condition of avian eggshells and has been retained more often in taxa that nest in humid infection-prone environments, suggesting that they serve critical roles in antimicrobial egg defence. PMID:27488648

  6. Breeding for cuticle-associated traits in crop species: traits, targets, and strategies.

    Science.gov (United States)

    Petit, Johann; Bres, Cécile; Mauxion, Jean-Philippe; Bakan, Bénédicte; Rothan, Christophe

    2017-11-09

    Improving crop productivity and quality while promoting sustainable agriculture have become major goals in plant breeding. The cuticle is a natural film covering the aerial organs of plants and consists of lipid polyesters covered and embedded with wax. The cuticle protects plants against water loss and pathogens and affects traits with strong impacts on crop quality such as, for horticultural crops, fruit brightness, cracking, russeting, netting, and shelf life. Here we provide an overview of the most important cuticle-associated traits that can be targeted for crop improvement. To date, most studies on cuticle-associated traits aimed at crop breeding have been done on fleshy fruits. Less information is available for staple crops such as rice, wheat or maize. Here we present new insights into cuticle formation and properties resulting from the study of genetic resources available for the various crop species. Our review also covers the current strategies and tools aimed at exploiting available natural and artificially induced genetic diversity and the technologies used to transfer the beneficial alleles affecting cuticle-associated traits to commercial varieties. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  7. 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. Copyright © 2011 Elsevier Inc. All rights reserved.

  8. The use of flow cytometry to monitor chitin synthesis in regenerating protoplasts of Candida albicans.

    Science.gov (United States)

    Hector, R F; Braun, P C; Hart, J T; Kamarck, M E

    1990-01-01

    Flow cytometry was used to monitor chitin synthesis in regenerating protoplasts of the yeast Candida albicans. Comparisons of cells stained with Calcofluor White, a fluorochrome with known affinity for chitin, and cells incubated in the presence of N-[3H]-acetylglucosamine, the precursor substrate for chitin, showed a linear relationship between fluorescence and incorporation of label over time. Changes in both the fluorescence and light scatter of regenerating protoplasts treated with inhibitors of fungal chitin synthase were also quantitated by flow cytometry.

  9. 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...

  10. Response of the chitinolytic microbial community to chitin amendments of dune soils

    NARCIS (Netherlands)

    De Boer, W.; Gerards, S.; Klein Gunnewiek, P.J.A.; Modderman, R.

    1999-01-01

    The dynamics of culturable chitin-degrading microorganisms were studied during a 16-week incubation of chitin-amended coastal dune soils that differed in acidity. Soil samples were incubated at normal (5% Why) and high (15% w/w) moisture levels. More than half of the added chitin was decomposed

  11. Effect of gamma radiation on chitin-nanosilver membranes

    International Nuclear Information System (INIS)

    Singh, Rita; Singh, Durgeshwer

    2014-01-01

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

  12. Chemical and structural analysis of Eucalyptus globulus and E. camaldulensis leaf cuticles: a lipidized cell wall region

    Directory of Open Access Journals (Sweden)

    Paula eGuzmán

    2014-09-01

    Full Text Available The plant cuticle has traditionally been conceived as an independent hydrophobic layer that covers the external epidermal cell wall. Due to its complexity, the existing relationship between cuticle chemical composition and ultra-structure remains unclear to date. This study aimed to examine the link between chemical composition and structure of isolated, adaxial leaf cuticles of Eucalyptus camaldulensis and E. globulus by the gradual extraction and identification of lipid constituents (cutin and soluble lipids, coupled to spectroscopic and microscopic analyses. The soluble compounds and cutin monomers identified could not be assigned to a concrete internal cuticle ultra-structure. After cutin depolymerization, a cellulose network resembling the cell wall was observed, with different structural patterns in the regions ascribed to the cuticle proper and cuticular layer, respectively. Our results suggest that the current cuticle model should be revised, stressing the presence and major role of cell wall polysaccharides. It is concluded that the cuticle may be interpreted as a modified cell wall region which contains additional lipids. The major heterogeneity of the plant cuticle makes it difficult to establish a direct link between cuticle chemistry and structure with the existing methodologies.

  13. Slow food: insect prey and chitin induce phytohormone accumulation and gene expression in carnivorous Nepenthes plants.

    Science.gov (United States)

    Yilamujiang, Ayufu; Reichelt, Michael; Mithöfer, Axel

    2016-08-01

    Carnivorous Nepenthes plants use modified leaves forming pitfall traps to capture and digest prey, mainly insects, for additional nutrient supply. These traps, so called pitchers, contain a plant-derived fluid composed of many hydrolytic enzymes and defence-related proteins. In this study, the prey-induced induction of corresponding genes of those proteins and a role for phytohormones in this process was analysed. Tissue from insect prey-fed, chitin- and phytohormone-challenged pitchers was harvested and analysed for selected gene expressions by a quantitative PCR technique. Phytohormone levels were determined by LC-MS/MS. Nepenthesin proteolytic activities were measured in the digestive fluid using a fluorescence substrate. Insect prey in the pitchers induced the accumulation of phytohormones such as jasmonates as well as the transcription of studied genes encoding a chitinase 3 and a protease (nepenthesin I), whereas a defence-related protein (PR-1) gene was not induced. Treatment with chitin as a component of the insects' exoskeleton triggered the accumulation of jasmonates, the expression of nepenthesin I and chitinase 3 genes similar to jasmonic acid treatment, and induced protease activity in the fluid. All detectable responses were slowly induced. The results suggest that upon insect prey catch a sequence of signals is initiated: (1) insect-derived chitin, (2) jasmonate as endogenous phytohormone signal, (3) the induction of digestive gene expression and (4) protein expression. This resembles a similar hierarchy of events as described from plant pathogen/herbivore interactions, supporting the idea that carnivory evolved from plant defences. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

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

    International Nuclear Information System (INIS)

    Junkasem, Jirawut; Rujiravanit, Ratana; Supaphol, Pitt

    2006-01-01

    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

  15. The Effect of Poly (Glycerol Sebacate) Incorporation within Hybrid Chitin-Lignin Sol-Gel Nanofibrous Scaffolds.

    Science.gov (United States)

    Abudula, Tuerdimaimaiti; Gzara, Lassaad; Simonetti, Giovanna; Alshahrie, Ahmed; Salah, Numan; Morganti, Pierfrancesco; Chianese, Angelo; Fallahi, Afsoon; Tamayol, Ali; Bencherif, Sidi A; Memic, Adnan

    2018-03-19

    Chitin and lignin primarily accumulate as bio-waste resulting from byproducts of crustacean crusts and plant biomass. Recently, their use has been proposed for diverse and unique bioengineering applications, amongst others. However, their weak mechanical properties need to be improved in order to facilitate their industrial utilization. In this paper, we fabricated hybrid fibers composed of a chitin-lignin (CL)-based sol-gel mixture and elastomeric poly (glycerol sebacate) (PGS) using a standard electrospinning approach. Obtained results showed that PGS could be coherently blended with the sol-gel mixture to form a nanofibrous scaffold exhibiting remarkable mechanical performance and improved antibacterial and antifungal activity. The developed hybrid fibers showed promising potential in advanced biomedical applications such as wound care products. Ultimately, recycling these sustainable biopolymers and other bio-wastes alike could propel a "greener" economy.

  16. Rheological study of chitosan acetate solutions containing chitin nanofibrils

    Czech Academy of Sciences Publication Activity Database

    Mikešová, Jana; Hašek, Jindřich; Tishchenko, Galina; Morganti, P.

    2014-01-01

    Roč. 112, 4 November (2014), s. 753-757 ISSN 0144-8617 EU Projects: European Commission(XE) 315233 - N-CHITOPACK Institutional support: RVO:61389013 Keywords : rheology * chitosan solutions * chitin nanofibrils Subject RIV: CD - Macromolecular Chemistry Impact factor: 4.074, year: 2014

  17. Chitin degrading potential of three aquatic actinomycetes and its ...

    African Journals Online (AJOL)

    PRECIOUS

    2009-12-01

    Dec 1, 2009 ... chitinase production by all tested actinomycetes was at pH 8. S. canus and M. ... Chitin is the most abundant biopolymer next to cellulose. It is the β –1, ... Microorganisms, lower animals, birds, fungi and plants are known to ...

  18. Chitin elicitation of natural product production in marine bacteria

    DEFF Research Database (Denmark)

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

    -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...

  19. Adsorption studies of iron(III) on chitin

    Indian Academy of Sciences (India)

    Unknown

    of particle size and dosage of the adsorbant, contact time, initial concentration of the adsorbate and tem- perature were experimentally ... Adsorption; chitin; variable parameters; fraction of adsorption; temperature effect. 1. Introduction. Iron is one of the ... about the presence of iron in drinking water is its ob- jectionable taste.

  20. Experimental evaluation of new chitin-chitosan graft for duraplasty.

    Science.gov (United States)

    Pogorielov, M; Kravtsova, A; Reilly, G C; Deineka, V; Tetteh, G; Kalinkevich, O; Pogorielova, O; Moskalenko, R; Tkach, G

    2017-02-01

    Natural materials such as collagen and alginate have promising applications as dural graft substitutes. These materials are able to restore the dural defect and create optimal conditions for the development of connective tissue at the site of injury. A promising material for biomedical applications is chitosan-a linear polysaccharide obtained by the deacetylation of chitin. It has been found to be nontoxic, biodegradable, biofunctional and biocompatible in addition to having antimicrobial characteristics. In this study we designed new chitin-chitosan substitutes for dura mater closure and evaluated their effectiveness and safety. Chitosan films were produced from 3 % of chitosan (molar mass-200, 500 or 700 kDa, deacetylation rate 80-90%) with addition of 20% of chitin. Antimicrobial effictively and cell viability were analysed for the different molar masses of chitosan. The film containing chitosan of molar mass 200 kDa, had the best antimicrobial and biological activity and was successfully used for experimental duraplasty in an in vivo model. In conclusion the chitin-chitosan membrane designed here met the requirements for a dura matter graft exhibiting the ability to support cell growth, inhibit microbial growth and biodegradade at an appropriate rate. Therefore this is a promising material for clinical duroplasty.

  1. Cuticle ultrastructure, cuticular lipid composition, and gene expression in hypoxia-stressed Arabidopsis stems and leaves.

    Science.gov (United States)

    Kim, Hyojin; Choi, Dongsu; Suh, Mi Chung

    2017-06-01

    An increased permeability of the cuticle is closely associated with downregulation of genes involved in cuticular lipid synthesis in hypoxia-stressed Arabidopsis and may allow plants to cope with oxygen deficiency. The hydrophobic cuticle layer consisting of cutin polyester and cuticular wax is the first barrier to protect the aerial parts of land plants from environmental stresses. In the present study, we investigated the role of cuticle membrane in Arabidopsis responses to oxygen deficiency. TEM analysis showed that the epidermal cells of hypoxia-treated Arabidopsis stems and leaves possessed a thinner electron-translucent cuticle proper and a more electron-dense cuticular layer. A reduction in epicuticular wax crystal deposition was observed in SEM images of hypoxia-treated Arabidopsis stem compared with normoxic control. Cuticular transpiration was more rapid in hypoxia-stressed leaves than in normoxic control. Total wax and cutin loads decreased by approximately 6-12 and 12-22%, respectively, and the levels of C29 alkanes, secondary alcohols, and ketones, C16:0 ω-hydroxy fatty acids, and C18:2 dicarboxylic acids were also prominently reduced in hypoxia-stressed Arabidopsis leaves and/or stems relative to normoxic control. Genome-wide transcriptome and quantitative RT-PCR analyses revealed that the expression of several genes involved in the biosynthesis and transport of cuticular waxes and cutin monomers were downregulated more than fourfold, but no significant alterations were detected in the transcript levels of fatty acid biosynthetic genes, BCCP2, PDH-E1α, and ENR1 in hypoxia-treated Arabidopsis stems and leaves compared with normoxic control. Taken together, an increased permeability of the cuticle is closely associated with downregulation of genes involved in cuticular lipid synthesis in hypoxia-stressed Arabidopsis. The present study elucidates one of the cuticle-related adaptive responses that may allow plants to cope with low oxygen levels.

  2. Development and evaluation of 5-fluorouracil loaded chitin nanogels for treatment of skin cancer.

    Science.gov (United States)

    Sabitha, M; Sanoj Rejinold, N; Nair, Amrita; Lakshmanan, Vinoth-Kumar; Nair, Shantikumar V; Jayakumar, R

    2013-01-02

    This study focuses on development and evaluation of 5-fluorouracil (5-FU) loaded chitin nanogels (FCNGs). It formed good, stable aqueous dispersion with spherical particles in 120-140 nm size range and showed pH responsive swelling and drug release. The FCNGs showed toxicity on melanoma (A375) in a concentration range of 0.4-2.0mg/mL, but less toxicity toward human dermal fibroblast (HDF) cells by MTT assay. Confocal analysis revealed uptake of FCNGs by both cells. From skin permeation experiments, FCNGs showed almost same steady state flux as that of control 5-FU but the retention in the deeper layers of skin was found to be 4-5 times more from FCNGs. Histopathological evaluation revealed loosening of the horny layer of epidermis by interaction of cationically charged chitin, with no observed signs of inflammation and so FCNGs can be a good option for treatment of skin cancers. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. Sugar-Binding Profiles of Chitin-Binding Lectins from the Hevein Family: A Comprehensive Study

    Directory of Open Access Journals (Sweden)

    Yoko Itakura

    2017-05-01

    Full Text Available Chitin-binding lectins form the hevein family in plants, which are defined by the presence of single or multiple structurally conserved GlcNAc (N-acetylglucosamine-binding domains. Although they have been used as probes for chito-oligosaccharides, their detailed specificities remain to be investigated. In this study, we analyzed six chitin-binding lectins, DSA, LEL, PWM, STL, UDA, and WGA, by quantitative frontal affinity chromatography. Some novel features were evident: WGA showed almost comparable affinity for pyridylaminated chitotriose and chitotetraose, while LEL and UDA showed much weaker affinity, and DSA, PWM, and STL had no substantial affinity for the former. WGA showed selective affinity for hybrid-type N-glycans harboring a bisecting GlcNAc residue. UDA showed extensive binding to high-mannose type N-glycans, with affinity increasing with the number of Man residues. DSA showed the highest affinity for highly branched N-glycans consisting of type II LacNAc (N-acetyllactosamine. Further, multivalent features of these lectins were investigated by using glycoconjugate and lectin microarrays. The lectins showed substantial binding to immobilized LacNAc as well as chito-oligosaccharides, although the extents to which they bound varied among them. WGA showed strong binding to heavily sialylated glycoproteins. The above observations will help interpret lectin-glycoprotein interactions in histochemical studies and glyco-biomarker investigations.

  4. Nano-fibrin stabilized CaSO4 crystals incorporated injectable chitin composite hydrogel for enhanced angiogenesis & osteogenesis.

    Science.gov (United States)

    Arun Kumar, R; Sivashanmugam, A; Deepthi, S; Bumgardner, Joel D; Nair, Shantikumar V; Jayakumar, R

    2016-04-20

    Calcium sulfate (CaSO4), an excellent biodegradable bone forming agent that is an ideal choice as additive in gels, however, its disadvantage being poor gel rheology and angiogenesis. Here, we have synthesized chitin-CaSO4-nano-fibrin based injectable gel system which shows improved rheology and angiogenic potential. Rheological studies showed that the composite gel was a shear thinning gel with elastic modulus of 15.4±0.275kPa; a 1.67 fold increase over chitin control. SEM and XRD analyses revealed the effect of nano-fibrin (nFibrin) in transforming CaSO4 crystal shape from needle to hexagonal. It also masked the retarding effect of CaSO4 towards in vitro early cell attachment and angiogenesis using rabbit adipose derived mesenchymal stem cells (rASCs) and HUVECs, respectively. rASCs osteogenesis was confirmed by spectrophotometric endpoint assay, which showed 6-fold early increase in alkaline phosphatase levels and immuno-cytochemistry analysis. These in vitro results highlight the potential of injectable chitin-CaSO4-nFibrin gel for osteo-regeneration via enhanced angiogenesis. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

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

    2014-11-01

    Plants are constantly exposed to threats from pathogenic microbes and thus developed an innate immune system to protect themselves. On the other hand, many plants also have the ability to establish endosymbiosis with beneficial microbes such as arbuscular mycorrhizal (AM) fungi or rhizobial bacteria, which improves the growth of host plants. How plants evolved these systems managing such opposite plant-microbe interactions is unclear. We show here that knockout (KO) mutants of OsCERK1, a rice receptor kinase essential for chitin signaling, were impaired not only for chitin-triggered defense responses but also for AM symbiosis, indicating the bifunctionality of OsCERK1 in defense and symbiosis. On the other hand, a KO mutant of OsCEBiP, which forms a receptor complex with OsCERK1 and is essential for chitin-triggered immunity, established mycorrhizal symbiosis normally. Therefore, OsCERK1 but not chitin-triggered immunity is required for AM symbiosis. Furthermore, experiments with chimeric receptors showed that the kinase domains of OsCERK1 and homologs from non-leguminous, mycorrhizal plants could trigger nodulation signaling in legume-rhizobium interactions as the kinase domain of Nod factor receptor1 (NFR1), which is essential for triggering the nodulation program in leguminous plants, did. Because leguminous plants are believed to have developed the rhizobial symbiosis on the basis of AM symbiosis, our results suggest that the symbiotic function of ancestral CERK1 in AM symbiosis enabled the molecular evolution to leguminous NFR1 and resulted in the establishment of legume-rhizobia symbiosis. These results also suggest that OsCERK1 and homologs serve as a molecular switch that activates defense or symbiotic responses depending on the infecting microbes. © The Author 2014. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  6. Fluorescence microscopical studies on chitin distribution in the cell wall of giant cells of Saccharomyces uvarum, grown following X-radiaiton treatment. Fluoreszenzmikroskopische Untersuchungen zur Chitinverteilung in der Zellwand von Riesenzellen von Saccharomyces uvarum, gewachsen nach Roentgenbestrahlung

    Energy Technology Data Exchange (ETDEWEB)

    Hoschka, L

    1982-01-01

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

  7. Fluorescence microscopical studies on chitin distribution in the cell wall of giant cells of Saccharomyces uvarum, grown following X-radiation treatment. Fluoreszenzmikroskopische Untersuchungen zur Chitinverteilung in der Zellwand von Riesenzellen von Saccharomyces uvarum, gewachsen nach Roentgenbestrahlung

    Energy Technology Data Exchange (ETDEWEB)

    Hoschka, L

    1982-01-01

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

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

    Science.gov (United States)

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

    2012-09-01

    Graft copolymerization of acrylic acid (AA) on chitin nanofibers was carried out with potassium persulfate as a free radical initiator in an aqueous medium. The molar ratio of grafted AA increased with the AA concentration. The grafted chitin nanofibers were characterized by FT-IR, FE-SEM, UV-vis, XRD, and TGA. After polymerization, the characteristic morphology of chitin nanofibers was maintained. Chitin nanofibers grafted with AA were efficiently dissociated and dispersed homogeneously in basic water because of the electrostatic repulsion effect between nanofibers. AA was grafted on the surface and amorphous part of chitin nanofibers, and the original crystalline structure of α-chitin was maintained. At 330 °C, the weight residue of the graft copolymer increased with the grafted AA content. Copyright © 2012 Elsevier Ltd. All rights reserved.

  9. Structure and Properties of Chitin Whisker Reinforced Papers for Food Packaging Application

    Directory of Open Access Journals (Sweden)

    Zhihan Li

    2015-04-01

    Full Text Available In recent years, concerns about environmental waste caused by petroleum-derived chemicals as well as the consumer's demand for high quality food products, have prompted people to pay more attention to developing biodegradable food packaging materials using natural resources such as cellulose fibers and chitin derivatives. In this study, chitin whiskers have been successfully generated by hydrolyzing the α-chitin sample. Then the synthesized nano-sized chitin whiskers were used at ratios from 0.1% to 2% (wt% for improving strength properties of paper sheets by the dip-coating method. Transmission electron microscopy (TEM and field emission scanning electron microscopy (FE-SEM were used to investigate the morphology of chitin whiskers and cellulose fiber compounds. The results showed that coating with chitin whiskers brought about an increase in tear strength, burst strength, and wet and dry tensile strength, with a decrease in Zeta-potential value.

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

    Directory of Open Access Journals (Sweden)

    Alessandro Ianiro

    2014-12-01

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

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

    Directory of Open Access Journals (Sweden)

    Junhe Cui

    2016-01-01

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

  12. 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. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Structural changes in cuticles on violin bow hair caused by wear.

    Science.gov (United States)

    Yamamoto, Tomoko; Sugiyama, Shigeru

    2010-01-01

    A bow with horse tail hair is used to play the violin. New and worn-out bow hairs were observed by atomic force microscopy. The cuticles of the new bow hair were already damaged by bleach and delipidation, however the worn-out bow hairs were much more damaged and broken off by force, which relates to wearing out.

  14. Cuticle deposition in imaginal disks: effects of juvenile hormone and fat body in vitro.

    Science.gov (United States)

    Oberlander, H; Tomblin, C

    1972-08-04

    Wing disks from the last larval instar of the Indian meal moth, Plodia interpunctella (Hübner), were successfully cultured in modified Grace's medium. 20-Hydroxyecdysone induced cuticle deposition in these disks in vitro. This response was enhanced by treating the medium with larval fat body and was inhibited by application of juvenile hormone.

  15. How does the nectar of stomata-free nectaries cross the cuticle?

    Directory of Open Access Journals (Sweden)

    Elder Antônio Sousa Paiva

    Full Text Available ABSTRACT In many glandular structures, departure from the cell is only one step in the process of exudate release to the plant surface. Here the set of events that lead nectar to the external environment is presented and discussed mainly for stomata-free nectaries. After being synthesized, the nectar or some of its component needs to be released to the environment where it performs its functions. Nectar precursors derived from cell metabolism need to cross several barriers, such as the cell membrane and cell wall, in order to become nectar. Then the nectar must cross the cuticle or pass through stomata in order to be offered to plant mutualists. Release through stomata is a simple mechanism, but the ways by which nectar crosses the cuticle is still controversial. Hydrophilic pathways in the cuticle and repetitive cycles of rupture or cuticle detachment are the main routes for nectar release in stomata-free nectaries. In addition to nectar, there are other exogenous secretions that must leave the protoplast and reach the plant surface to perform their function. The ways by which nectar is released discussed herein are likely relevant to understanding the release of other hydrophilic products of the secretory process of plants.

  16. Colloidal chitin nanogels: A plethora of applications under one shell.

    Science.gov (United States)

    Vishnu Priya, M; Sabitha, M; Jayakumar, R

    2016-01-20

    Chitin nanogels (CNGs) are a relatively new class of natural polymeric nanomaterials which have a large potential in the field of drug delivery and nanotherapeutics. These nanogels being very biocompatible are non-toxic when internalized by cells. In this review various properties, preparation techniques and applications of CNGs have been described. CNGs because of their nano-size possess certain unique properties which enable them to be used in a number of biomedical applications. CNGs are prepared by simple regeneration technique without using any cross-linkers. Various polymers, drugs and fluorescent dyes can be blended or incorporated or labelled with the chitin hydrogel network. Drugs and molecules encapsulated within CNGs can be used for targeted delivery, in vivo monitoring or even for therapeutic purposes. Here various applications of CNGs in the field of drug delivery, imaging, sensing and therapeutics have been discussed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. A novel Arabidopsis CHITIN ELICITOR RECEPTOR KINASE 1 (CERK1) mutant with enhanced pathogen-induced cell death and altered receptor processing.

    Science.gov (United States)

    Petutschnig, Elena K; Stolze, Marnie; Lipka, Ulrike; Kopischke, Michaela; Horlacher, Juliane; Valerius, Oliver; Rozhon, Wilfried; Gust, Andrea A; Kemmerling, Birgit; Poppenberger, Brigitte; Braus, Gerhard H; Nürnberger, Thorsten; Lipka, Volker

    2014-12-01

    Plants detect pathogens by sensing microbe-associated molecular patterns (MAMPs) through pattern recognition receptors. Pattern recognition receptor complexes also have roles in cell death control, but the underlying mechanisms are poorly understood. Here, we report isolation of cerk1-4, a novel mutant allele of the Arabidopsis chitin receptor CERK1 with enhanced defense responses. We identified cerk1-4 in a forward genetic screen with barley powdery mildew and consequently characterized it by pathogen assays, mutant crosses and analysis of defense pathways. CERK1 and CERK1-4 proteins were analyzed biochemically. The cerk1-4 mutation causes an amino acid exchange in the CERK1 ectodomain. Mutant plants maintain chitin signaling capacity but exhibit hyper-inducible salicylic acid concentrations and deregulated cell death upon pathogen challenge. In contrast to chitin signaling, the cerk1-4 phenotype does not require kinase activity and is conferred by the N-terminal part of the receptor. CERK1 undergoes ectodomain shedding, a well-known process in animal cell surface proteins. Wild-type plants contain the full-length CERK1 receptor protein as well as a soluble form of the CERK1 ectodomain, whereas cerk1-4 plants lack the N-terminal shedding product. Our work suggests that CERK1 may have a chitin-independent role in cell death control and is the first report of ectodomain shedding in plants. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

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

    Science.gov (United States)

    Nampally, Malathi; Rajulu, M B Govinda; Gillet, Dominique; Suryanarayanan, T S; Moerschbacher, Bruno B

    2015-01-01

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

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

    Science.gov (United States)

    Nampally, Malathi; Rajulu, M. B. Govinda; Gillet, Dominique; Suryanarayanan, T. S.; Moerschbacher, Bruno B.

    2015-01-01

    Chitin is one of the most abundant biomolecules on earth, and its partially de-N-acetylated counterpart, chitosan, is one of the most promising biotechnological resources due to its diversity in structure and function. Recently, chitin and chitosan modifying enzymes (CCMEs) have gained increasing interest as tools to engineer chitosans with specific functions and reliable performance in biotechnological and biomedical applications. In a search for novel CCME, we isolated chitinolytic and chitosanolytic microorganisms from soils with more than ten-years history of chitin and chitosan exposure and screened them for chitinase and chitosanase isoenzymes as well as for their patterns of oligomeric products by incubating their secretomes with chitosan polymers. Of the 60 bacterial strains isolated, only eight were chitinolytic and/or chitosanolytic, while 20 out of 25 fungal isolates were chitinolytic and/or chitosanolytic. The bacterial isolates produced rather similar patterns of chitinolytic and chitosanolytic enzymes, while the fungal isolates produced a much broader range of different isoenzymes. Furthermore, diverse mixtures of oligosaccharides were formed when chitosan polymers were incubated with the secretomes of select fungal species. Our study indicates that soils with a history of chitin and chitosan exposure are a good source of novel CCME for chitosan bioengineering. PMID:26273652

  20. Down-regulation of a chitin synthase a gene by RNA interference enhances pathogenicity of Beauveria bassiana ANU1 against Spodoptera exigua (HÜBNER).

    Science.gov (United States)

    Lee, Jung-Bok; Kim, Hyun Soo; Park, Youngjin

    2017-02-01

    Chitin synthase (CHS) is an important enzymatic component, which is required for chitin formation in the cuticles and cuticular linings of other tissues in insects. CHSs have been divided into two classes, classes A and B, based on their amino acid sequence similarities and functions. Class A CHS (CHS-A) is specifically expressed in the epidermis and related ectodermal cells such as tracheal cells, while class B CHS (CHS-B) is expressed in gut epithelial cells that produce peritrophic matrices. In this study, we cloned the CHS-A gene from the beet armyworm, Spodoptera exigua (SeCHS-A). The SeCHS-A contains an open reading frame of 4,698 nucleotides, encoding a protein of 1,565 amino acids with a predicted molecular mass of approximately 177.8 kDa. The SeCHS-A mRNA was expressed in all developmental stages and specifically in the epidermis and tracheae tissue by quantitative real-time-PCR analysis. Expression of SeCHS-A gene was suppressed by feeding double-stranded RNA (dsCHS-A, 400 ng/larva) in the third instar larvae of S. exigua. Suppression of the SeCHS-A gene expression significantly increased 35% of mortality on pupation of S. exigua. Also, the third instar larvae fed with dsCHS-A significantly increased susceptibility to entomopathogenic fungi, Beauveria bassiana ANU1 at 3 days after treatment. These results suggest that the SeCHS-A gene plays an important role in development of S. exigua and RNA interference may apply to effective pest control with B. bassiana. © 2017 Wiley Periodicals, Inc.

  1. 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. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Evaluation of Chitin as Natural Coagulant in Water Treatment

    Directory of Open Access Journals (Sweden)

    V. Saritha

    2012-04-01

    Full Text Available The use of synthetic coagulants is not regarded as suitable due to health and economic considerations. The present study was aimed to investigate the effects of alum as coagulant in conjunction with chitin as coagulant aid on the removal of turbidity, hardness and Escherichia coli from water. A conventional jar test apparatus was employed for the tests. The experiment was conducted at three different pH conditions of 6, 7 and 8. The dosages chosen were 0.5, 1, 1.5 and 2mg/l. The results showed that turbidity decrease provided also a primary Escherichia coli reduction. Hardness removal efficiency was observed to be 93% at pH 7 with 1mg/l concentration by alum whereas chitin was stable at all the pH ranges showing highest removal at 1 and 1.5mg/l with pH 7. At low concentration chitin showed marginally better performance on hardness. In conclusion, using natural coagulants results in considerable savings in chemicals and sludge handling cost may be achieved.

  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. Facile nanofibrillation of chitin derivatives by gas bubbling and ultrasonic treatments in water.

    Science.gov (United States)

    Tanaka, Kohei; Yamamoto, Kazuya; Kadokawa, Jun-ichi

    2014-10-29

    In this paper, we report that nanofiber network structures were constructed from chitin derivatives by gas bubbling and ultrasonic treatments in water. When chitin was first subjected to N2 gas bubbling with ultrasonication in water, the SEM images of the product showed nanofiber network morphology. However, nanofiber network was not re-constructed by the same N2 gas bubbling and ultrasonic treatments after agglomeration. We then have paid attention to an amidine group to provide the agglomeration-nanofibrillation behavior of chitin derivatives. An amidinated chitin was synthesized by the reaction of the amino groups in a partially deacetylated chitin with N,N-dimethylacetamide dimethyl acetal, which was subjected to CO2 gas bubbling and ultrasonic treatments in water to convert into an amidinium chitin by protonation. The SEM images of the product clearly showed nanofiber network morphology. We further examined re-nanofibrillation of the agglomerated material, which was obtained by mixing the nanofibrillated amidinium chitin with water, followed by drying under reduced pressure. Consequently, the material was re-nanofibrillated by N2 gas bubbling with ultrasonication in water owing to electrostatic repulsion between the amidinium groups. Furthermore, deprotonation of the amidinium chitin and re-protonation of the resulting amidinated chitin were conducted by alkaline treatment and CO2 gas bubbling-ultrasonic treatments, respectively. The material showed the agglomeration-nanofibrillation behavior during the processes. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Elevated Chitin Content Reduces the Susceptibility of Candida Species to Caspofungin

    Science.gov (United States)

    Walker, Louise A.; Gow, Neil A. R.

    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. PMID:23089748

  6. Characterization and role of a metalloprotease induced by chitin in Serratia sp. KCK.

    Science.gov (United States)

    Kim, Hyun-Soo; Golyshin, Peter N; Timmis, Kenneth N

    2007-11-01

    A metalloprotease induced by chitin in a new chitinolytic bacterium Serratia sp. Strain KCK was purified and characterized. Compared with other Serratia enzymes, it exhibited a rather broad pH activity range (pH 5.0-8.0), and thermostability. The cognate ORF, mpr, was cloned and expressed. Its deduced amino acid sequence showed high similarity to those of bacterial zinc-binding metalloproteases and a well-conserved serralysin family motif. Pretreatment of chitin with the Mpr protein promoted chitin degradation by chitinase A, which suggests that Mpr participates in, and facilitates, chitin degradation by this microorganism.

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

    Science.gov (United States)

    Ospina Álvarez, Sandra Patricia; Ramírez Cadavid, David Alexander; Ossa Orozco, Claudia Patricia; Zapata Ocampo, Paola; Atehortúa, Lucía

    2014-01-01

    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. PMID:24551839

  8. Physicochemical and antifungal properties of bio-nanocomposite film based on gelatin-chitin nanoparticles.

    Science.gov (United States)

    Sahraee, Samar; Milani, Jafar M; Ghanbarzadeh, Babak; Hamishehkar, Hamed

    2017-04-01

    The gelatin-based nanocomposite films containing chitin nanoparticles (N-chitin) with concentrations of 0, 3, 5 and 10% were prepared and their physical, thermal and anti-microbial properties were investigated. Scanning electron microscopy (SEM) micrographs showed that N-chitin size distribution was around 60-70nm which dispersed appropriately at low concentration in gelatin matrix. The results showed that incorporation of N-chitin significantly influenced apparent color and transparency of the gelatin films. The reduced water vapor permeability (WVP) and solubility and higher surface hydrophobicity of the nanocomposite films were obtained by enhancing N-chitin concentration in film formulation. The use of N-chitin up to 5% concentration in the gelatin based nanocomposite film led to improved mechanical properties. Also, the results of differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) confirmed improved stability of nanocomposite films against melting and degradation at high temperatures in comparison to neat gelatin film. The well compatibility of chitin nanoparticles with gelatin polymer was concluded from Fourier transform infrared (FTIR) spectra and X-ray diffraction (XRD) plots. Finally, the gelatin based nanocomposite films had anti-fungal properties against Aspergillus niger in the contact surface zone. Increasing the concentration of N-chitin up to 5% enlarged inhibition zone diameter, but the nanocomposite film containing 10% N-chitin showed smaller inhibition zone. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Nonlinear Porous Diffusion Modeling of Hydrophilic Ionic Agrochemicals in Astomatous Plant Cuticle Aqueous Pores: A Mechanistic Approach.

    Science.gov (United States)

    Tredenick, Eloise C; Farrell, Troy W; Forster, W Alison; Psaltis, Steven T P

    2017-01-01

    The agricultural industry requires improved efficacy of sprays being applied to crops and weeds in order to reduce their environmental impact and deliver improved financial returns. Enhanced foliar uptake is one means of improving efficacy. The plant leaf cuticle is known to be the main barrier to diffusion of agrochemicals within the leaf. The usefulness of a mathematical model to simulate uptake of agrochemicals in plant cuticles has been noted previously in the literature, as the results of each uptake experiment are specific to each formulation of active ingredient, plant species and environmental conditions. In this work we develop a mathematical model and numerical simulation for the uptake of hydrophilic ionic agrochemicals through aqueous pores in plant cuticles. We propose a novel, nonlinear, porous diffusion model for ionic agrochemicals in isolated cuticles, which extends simple diffusion through the incorporation of parameters capable of simulating: plant species variations, evaporation of surface droplet solutions, ion binding effects on the cuticle surface and swelling of the aqueous pores with water. We validate our theoretical results against appropriate experimental data, discuss the key sensitivities in the model and relate theoretical predictions to appropriate physical mechanisms. Major influencing factors have been found to be cuticle structure, including tortuosity and density of the aqueous pores, and to a lesser extent humidity and cuticle surface ion binding effects.

  10. Nonlinear Porous Diffusion Modeling of Hydrophilic Ionic Agrochemicals in Astomatous Plant Cuticle Aqueous Pores: A Mechanistic Approach

    Directory of Open Access Journals (Sweden)

    Eloise C. Tredenick

    2017-05-01

    Full Text Available The agricultural industry requires improved efficacy of sprays being applied to crops and weeds in order to reduce their environmental impact and deliver improved financial returns. Enhanced foliar uptake is one means of improving efficacy. The plant leaf cuticle is known to be the main barrier to diffusion of agrochemicals within the leaf. The usefulness of a mathematical model to simulate uptake of agrochemicals in plant cuticles has been noted previously in the literature, as the results of each uptake experiment are specific to each formulation of active ingredient, plant species and environmental conditions. In this work we develop a mathematical model and numerical simulation for the uptake of hydrophilic ionic agrochemicals through aqueous pores in plant cuticles. We propose a novel, nonlinear, porous diffusion model for ionic agrochemicals in isolated cuticles, which extends simple diffusion through the incorporation of parameters capable of simulating: plant species variations, evaporation of surface droplet solutions, ion binding effects on the cuticle surface and swelling of the aqueous pores with water. We validate our theoretical results against appropriate experimental data, discuss the key sensitivities in the model and relate theoretical predictions to appropriate physical mechanisms. Major influencing factors have been found to be cuticle structure, including tortuosity and density of the aqueous pores, and to a lesser extent humidity and cuticle surface ion binding effects.

  11. Transcriptome Analysis of Mango (Mangifera indica L.) Fruit Epidermal Peel to Identify Putative Cuticle-Associated Genes

    Science.gov (United States)

    Tafolla-Arellano, Julio C.; Zheng, Yi; Sun, Honghe; Jiao, Chen; Ruiz-May, Eliel; Hernández-Oñate, Miguel A.; González-León, Alberto; Báez-Sañudo, Reginaldo; Fei, Zhangjun; Domozych, David; Rose, Jocelyn K. C.; Tiznado-Hernández, Martín E.

    2017-04-01

    Mango fruit (Mangifera indica L.) are highly perishable and have a limited shelf life, due to postharvest desiccation and senescence, which limits their global distribution. Recent studies of tomato fruit suggest that these traits are influenced by the expression of genes that are associated with cuticle metabolism. However, studies of these phenomena in mango fruit are limited by the lack of genome-scale data. In order to gain insight into the mango cuticle biogenesis and identify putative cuticle-associated genes, we analyzed the transcriptomes of peels from ripe and overripe mango fruit using RNA-Seq. Approximately 400 million reads were generated and de novo assembled into 107,744 unigenes, with a mean length of 1,717 bp and with this information an online Mango RNA-Seq Database (http://bioinfo.bti.cornell.edu/cgi-bin/mango/index.cgi) which is a valuable genomic resource for molecular research into the biology of mango fruit was created. RNA-Seq analysis suggested that the pathway leading to biosynthesis of the cuticle component, cutin, is up-regulated during overripening. This data was supported by analysis of the expression of several putative cuticle-associated genes and by gravimetric and microscopic studies of cuticle deposition, revealing a complex continuous pattern of cuticle deposition during fruit development and involving substantial accumulation during ripening/overripening.

  12. Structure and interactions of calcite spherulites with α-chitin in the brown shrimp (Penaeus aztecus) shell

    International Nuclear Information System (INIS)

    Heredia, A.; Aguilar-Franco, M.; Magana, C.; Flores, C.; Pina, C.; Velazquez, R.; Schaeffer, T.E.; Bucio, L.; Basiuk, V.A.

    2007-01-01

    White spots form in the brown shrimp (Penaeus aztecus, Decapoda) shell during frozen storage. The mineral formed consists of calcite incorporated into an amorphous α-chitin matrix. We studied mechanisms of interaction of amorphous α-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 α-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 μm in diameter). Our models of crystal-biopolymer interaction found high affinity of CO 3 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 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

  13. 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.

  14. Knickkopf protein protects and organizes chitin in the newly synthesized insect exoskeleton

    Science.gov (United States)

    New cuticle synthesis and molting are complex developmental processes that all insects must undergo to allow for growth. However, little is known about how insects regulate the selective degradation of the old cuticle while leaving the new one intact. In this study we show that in the red flour beet...

  15. Presence of a large β(1-3)glucan linked to chitin at the Saccharomyces cerevisiae mother-bud neck suggests involvement in localized growth control.

    Science.gov (United States)

    Cabib, Enrico; Blanco, Noelia; Arroyo, Javier

    2012-04-01

    Previous results suggested that the chitin ring present at the yeast mother-bud neck, which is linked specifically to the nonreducing ends of β(1-3)glucan, may help to suppress cell wall growth at the neck by competing with β(1-6)glucan and thereby with mannoproteins for their attachment to the same sites. Here we explored whether the linkage of chitin to β(1-3)glucan may also prevent the remodeling of this polysaccharide that would be necessary for cell wall growth. By a novel mild procedure, β(1-3)glucan was isolated from cell walls, solubilized by carboxymethylation, and fractionated by size exclusion chromatography, giving rise to a very high-molecular-weight peak and to highly polydisperse material. The latter material, soluble in alkali, may correspond to glucan being remodeled, whereas the large-size fraction would be the final cross-linked structural product. In fact, the β(1-3)glucan of buds, where growth occurs, is solubilized by alkali. A gas1 mutant with an expected defect in glucan elongation showed a large increase in the polydisperse fraction. By a procedure involving sodium hydroxide treatment, carboxymethylation, fractionation by affinity chromatography on wheat germ agglutinin-agarose, and fractionation by size chromatography on Sephacryl columns, it was shown that the β(1-3)glucan attached to chitin consists mostly of high-molecular-weight material. Therefore, it appears that linkage to chitin results in a polysaccharide that cannot be further remodeled and does not contribute to growth at the neck. In the course of these experiments, the new finding was made that part of the chitin forms a noncovalent complex with β(1-3)glucan.

  16. 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.

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

    International Nuclear Information System (INIS)

    Lakhtakia, Akhlesh; Motyka, Michael A; MartIn-Palma, Raul J; Pantano, Carlo G

    2009-01-01

    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. (communication)

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

    Energy Technology Data Exchange (ETDEWEB)

    Lakhtakia, Akhlesh; Motyka, Michael A [Materials Research Institute and Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, PA 16802 (United States); MartIn-Palma, Raul J; Pantano, Carlo G [Materials Research Institute and Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA 16802 (United States)], E-mail: akhlesh@psu.edu

    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. (communication)

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

    NARCIS (Netherlands)

    Kielak-Butterbach, A.M.; Cretoiu, M.S.; Semenov, A.V.; Sørensen, S.J.; van Elsas, J.D.

    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

  20. A simple procedure for preparing chitin oligomers through acetone precipitation after hydrolysis in concentrated hydrochloric acid.

    Science.gov (United States)

    Kazami, Nao; Sakaguchi, Masayoshi; Mizutani, Daisuke; Masuda, Tatsuhiko; Wakita, Satoshi; Oyama, Fumitaka; Kawakita, Masao; Sugahara, Yasusato

    2015-11-05

    Chitin oligomers are of interest because of their numerous biologically relevant properties. To prepare chitin oligomers containing 4-6 GlcNAc units [(GlcNAc)4-6], α- and β-chitin were hydrolyzed with concentrated hydrochloric acid at 40 °C. The reactant was mixed with acetone to recover the acetone-insoluble material, and (GlcNAc)4-6 was efficiently recovered after subsequent water extraction. Composition analysis using gel permeation chromatography and MALDI-TOF mass spectrometry indicated that (GlcNAc)4-6 could be isolated from the acetone-insoluble material with recoveries of approximately 17% and 21% from the starting α-chitin and β-chitin, respectively. The acetone precipitation method is highly useful for recovering chitin oligomers from the acid hydrolysate of chitin. The changes in the molecular size and higher-order structure of chitin during the course of hydrolysis were also analyzed, and a model that explains the process of oligomer accumulation is proposed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Determination of chitin content in fungal cell wall: an alternative flow cytometric method.

    Science.gov (United States)

    Costa-de-Oliveira, Sofia; Silva, Ana P; Miranda, Isabel M; Salvador, Alexandre; Azevedo, Maria M; Munro, Carol A; Rodrigues, Acácio G; Pina-Vaz, Cidália

    2013-03-01

    The conventional methods used to evaluate chitin content in fungi, such as biochemical assessment of glucosamine release after acid hydrolysis or epifluorescence microscopy, are low throughput, laborious, time-consuming, and cannot evaluate a large number of cells. We developed a flow cytometric assay, efficient, and fast, based on Calcofluor White staining to measure chitin content in yeast cells. A staining index was defined, its value was directly related to chitin amount and taking into consideration the different levels of autofluorecence. Twenty-two Candida spp. and four Cryptococcus neoformans clinical isolates with distinct susceptibility profiles to caspofungin were evaluated. Candida albicans clinical isolate SC5314, and isogenic strains with deletions in chitin synthase 3 (chs3Δ/chs3Δ) and genes encoding predicted GlycosylPhosphatidylInositol (GPI)-anchored proteins (pga31Δ/Δ and pga62Δ/Δ), were used as controls. As expected, the wild-type strain displayed a significant higher chitin content (P relationship between chitin content and antifungal drug susceptibility phenotype was found, an association was established between the paradoxical growth effect in the presence of high caspofungin concentrations and the chitin content. This novel flow cytometry protocol revealed to be a simple and reliable assay to estimate cell wall chitin content of fungi. Copyright © 2013 International Society for Advancement of Cytometry.

  2. The structure and dynamics of chitin nanofibrils in an aqueous environment revealed by molecular dynamics simulations

    Czech Academy of Sciences Publication Activity Database

    Střelcová, Z.; Kulhánek, P.; Friák, Martin; Fabritius, H.; Petrov, M.; Neugebauer, J.; Koča, J.

    2016-01-01

    Roč. 6, č. 36 (2016), s. 30710-30721 ISSN 2046-2069 Institutional support: RVO:68081723 Keywords : FREE-ENERGY CALCULATIONS * PARTICLE MESH EWALD * ALPHA-CHITIN * CRYSTAL-STRUCTURE * INSECT CHITIN * SURFACE-AREA * AB-INITIO Subject RIV: BO - Biophysics Impact factor: 3.108, year: 2016

  3. 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...

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

    DEFF Research Database (Denmark)

    Kielak, Anna; Cretoiu, Mariana; Semenov, Alexander

    2013-01-01

    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...

  5. Altering the expression of two chitin synthase genes differentially affects the growth and morphology of Aspergillus oryzae

    DEFF Research Database (Denmark)

    Müller, Christian; Hjort, C.M.; Hansen, K.

    2002-01-01

    In Aspergillus oryzae, one full-length chitin synthase (chsB) and fragments of two other chitin synthases (csmA and chsC) were identified. The deduced amino acid sequence of chsB was similar (87% identity) to chsB from Aspergillus nidulans, which encodes a class III chitin synthase. The sequence...

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

    NARCIS (Netherlands)

    Cretoiu, M.S.; Kielak, A.M.; Schluter, A.; van Elsas, J.D.

    2014-01-01

    Chitin and its derivatives are natural biopolymers that are often used as compounds for the control of soil-borne 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

  7. 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

    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

  8. LABORATORY EVALUATION OF ANDALIN, AN INSECT GROWTH REGULATOR INTERFERING WITH CUTICLE DEPOSITION, AGAINST MOSQUITO LARVAE

    Directory of Open Access Journals (Sweden)

    N REHIMI

    2002-12-01

    Full Text Available Andalin, a benzoylphenylurea (BPU derivative, was evaluated on Culex pipiens L. (Diptera: Culicidae. Treatment was made on newly 3rd- and 4th instar larvae for 24 h. The compound exhibited insecticidal activity and mortality occured after earlier inhibition of their development or by their inability to complete their ecdysis. Treatment resulted in a significant larvicidal effect and in a inhibition of adult emergence. Moreover, the compound disturbed growth and development since several morphological types and an increase in the duration of larval stage were observed. Histological study conducted on 4th instar larval integument, showed that Andalin caused a significant reduction in the thickness of cuticles secreted compared to controls. Thus, Andalin prevent molting in C. pipiens by interfering with cuticle deposition confirming the primary mode of action of this BPU insecticide.

  9. Chitin based polyurethanes using hydroxyl terminated polybutadiene, part III: surface characteristics.

    Science.gov (United States)

    Zia, Khalid Mahmood; Zuber, Mohammad; Saif, Muhammad Jawwad; Jawaid, Mohammad; Mahmood, Kashif; Shahid, Muhammad; Anjum, Muhammad Naveed; Ahmad, Mirza Nadeem

    2013-11-01

    Hydroxy terminated polybutadiene (HTPB)-chitin based polyurethanes (PUs) with controlled hydrophobicity were synthesized using HTPB and toluene diisocyanate (TDI). The prepolymer was extended with different mass ratios of chitin and 1,4-butane diol (BDO). The effect of chitin contents in chain extender (CE) proportions on surface properties was studied and investigated. Incorporation of chitin contents into the final PU showed decrease in contact angle value of water drop, water absorption (%) and swelling behavior. The antibacterial activity of the prepared samples was affected by varying the chitin contents in the chemical composition of the final PU. The results demonstrated that the use of prepared material can be suggested as non-absorbable suture. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. [In Vivo Study of Chitin in Fungal Hyphae Based on Confocal Raman Microscopy].

    Science.gov (United States)

    Li, Xiao-li; Luo, Liu-bin; Zhou, Bin-xiong; Hu, Xiao-qian; Sun, Chan-jun; He, Yong

    2016-01-01

    Chitin is an important structural polysaccharide of fungal cell wall. In this paper, aerial hyphae of Colletotrichum camelliae Massee was first studied by confocal Raman microscopy in vivo. Firstly, the optimal experimental parameters of hyphae for collecting the Raman spectra were determined, and the typical Raman spectra of hyphae, chitin standard and background were acquired. By comparing analysis, characteristic peaks of chitin were found in hyphae. Then, a region of interesting on hyphae was selected for Raman scanning. Through principal component analysis, the Raman signal of hyphae and background in the scanning area can be separated clearly. Combined with loading weight plot, two main characteristic peaks of hyphae were obtained, 1 622 cm(-1) was belong to chitin and 1 368 cm(-1) was assigned to pectic polysaccharide. Finally, two and three dimension chemical images of fungal hyphae were realized based on Raman fingerprint spectra of chitin in a nondestructive way.

  11. Regulation of C. elegans L4 cuticle collagen genes by the heterochronic protein LIN-29.

    Science.gov (United States)

    Abete-Luzi, Patricia; Eisenmann, David M

    2018-05-01

    The cuticle, the outer covering of the nematode C. elegans, is synthesized five times during the worm's life by the underlying hypodermis. Cuticle collagens, the major cuticle component, are encoded by a large family of col genes and, interestingly, many of these genes express predominantly at a single developmental stage. This temporal preference motivated us to investigate the mechanisms underlying col gene expression and here we focus on a subset of col genes expressed in the L4 stage. We identified minimal promoter regions of <300 bp for col-38, col-49, and col-63. In these regions, we predicted cis-regulatory sequences and evaluated their function in vivo via mutagenesis of a col-38p::yfp reporter. We used RNAi to study the requirement for candidate transcription regulators ELT-1 and ELT-3, LIN-29, and the LIN-29 co-factor MAB-10, and found LIN-29 to be necessary for the expression of four L4-specific genes (col-38, col-49, col-63, and col-138). Temporal misexpression of LIN-29 was also sufficient to activate these genes at a different developmental stage. The LIN-29 DNA-binding domain bound the col-38, col-49, and col-63 minimal promoters in vitro. For col-38 we showed that the LIN-29 sites necessary for reporter expression in vivo are also bound in vitro: this is the first identification of specific binding sites for LIN-29 necessary for in vivo target gene expression. © 2018 Wiley Periodicals, Inc.

  12. Herbicide effects on cuticle ultrastructure in Eleusine indica and Portulaca oleracea.

    Science.gov (United States)

    Malpassi, Rosana N

    2006-04-01

    Eleusine indica and Portulaca oleracea are two common weeds in peanut crops in southern Córdoba. Two chemicals are frequently used to control them, quizalofop for grasses and lactofen for dicots. The objective is to study the effects of quizalofop and lactofen on cuticle ultrastructure in E. indica and P. oleracea, respectively. In the lab, quizalofop was applied on E. indica and lactofen on P. oleracea. Three plant categories were analyzed in each species: 3, 1-2, and no tiller in E. indica, and 8, 6, and 2 nomophylls in P. oleracea. Leaf samples from both species were collected at 7 and 16 days post-application and were treated for scanning electron microscopy. E. indica cuticle treated with lethal dose shows areas where epicuticular waxes disappear, specially in the youngest individuals. These areas are located predominantly on periclinal walls of typical epidermic cells and subsidiary cells. On the other hand, P. oleracea shows cuticle discontinuities that may be caused by lactofen entry. They are smaller and less frequent in plants having 8 or more nomophylls. The remaining waxes act as a herbicide accumulation compartment and, therefore, would partially prevent the active ingredient entry to epidermic cells.

  13. Chemical Composition and Water Permeability of Fruit and Leaf Cuticles of Olea europaea L.

    Science.gov (United States)

    Huang, Hua; Burghardt, Markus; Schuster, Ann-Christin; Leide, Jana; Lara, Isabel; Riederer, Markus

    2017-10-11

    The plant cuticle, protecting against uncontrolled water loss, covers olive (Olea europaea) fruits and leaves. The present study describes the organ-specific chemical composition of the cuticular waxes and the cutin and compares three developmental stages of fruits (green, turning, and black) with the leaf surface. Numerous organ-specific differences, such as the total coverage of cutin monomeric components (1034.4 μg cm -2 and 630.5 μg cm -2 ) and the cuticular waxes (201.6 μg cm -2 and 320.4 μg cm -2 ) among all three fruit stages and leaves, respectively, were detected. Water permeability as the main cuticular function was 5-fold lower in adaxial leaf cuticles (2.1 × 10 -5 m s -1 ) in comparison to all three fruit stages (9.5 × 10 -5 m s -1 ). The three fruit developmental stages have the same cuticular water permeability. It is hypothesized that a higher weighted average chain length of the acyclic cuticular components leads to a considerably lower permeability of the leaf as compared to the fruit cuticle.

  14. A chitinase with two catalytic domains is required for organization of the cuticular extracellular matrix of a beetle.

    Directory of Open Access Journals (Sweden)

    Mi Young Noh

    2018-03-01

    Full Text Available Insect cuticle or exoskeleton is an extracellular matrix formed primarily from two different structural biopolymers, chitin and protein. During each molt cycle, a new cuticle is deposited simultaneously with degradation of the inner part of the chitinous procuticle of the overlying old exoskeleton by molting fluid enzymes including epidermal chitinases. In this study we report a novel role for an epidermal endochitinase containing two catalytic domains, TcCHT7, from the red flour beetle, Tribolium castaneum, in organizing chitin in the newly forming cuticle rather than in degrading chitin present in the prior one. Recombinant TcCHT7 expressed in insect cells is membrane-bound and capable of hydrolyzing an extracellular chitin substrate, whereas in vivo, this enzyme is also released from the plasma membrane and co-localizes with chitin in the entire procuticle. RNAi of TcCHT7 reveals that this enzyme is nonessential for any type of molt or degradation of the chitinous matrix in the old cuticle. In contrast, TcCHT7 is required for maintaining the integrity of the cuticle as a compact structure of alternating electron-dense and electron-lucent laminae. There is a reduction in thickness of elytral and leg cuticles after RNAi for TcCHT7. TcCHT7 is also required for formation of properly oriented long chitin fibers inside pore canals that are vertically oriented columnar structures, which contribute to the mechanical strength of a light-weight, yet rigid, adult cuticle. The conservation of CHT7-like proteins harboring such a unique domain configuration among many insect and other arthropod species indicates a critical role for the group III class of chitinases in the higher ordered organization of chitin fibers for development of the structural integrity of many invertebrate exoskeletons.

  15. Evidence of the exploitation of marine resource by the terrestrial insect Scapteriscus didactylus through stable isotope analyzes of its cuticle

    Directory of Open Access Journals (Sweden)

    Lelarge Caroline

    2006-05-01

    Full Text Available Abstract Background About 4 × 105 eggs in more than 5000 marine turtle nests are deposited every year on a 3.6 km long beach in French Guiana (South America. The dry biomass of eggs is estimated to be 5 × 103 kg, yet only 25% of this organic matter will return to the ocean in the form of hatchlings. Such amounts of organic matter are supposed to drive the functioning of the beach ecosystem. Previous studies have shown that egg predators and detritivorous organisms dominate the trophic relationships and the dynamics of the system. The role of a terrestrial insect Scapteriscus didactylus (Latreille, which damages up to 40% of the eggs of the marine turtle (Dermochelys coriacea, was unexpected. However it was impossible from direct observations to prove that the mole cricket consumed a significant amount of these eggs. Therefore, the precise place of the mole cricket in the nitrogen and carbon cycles of the beach ecosystem could not be determined. In order to answer this question, we looked for a marine signature of carbon and nitrogen source metabolized by the mole cricket. Results This study estimated the individual variability of δ13C and δ15N in the cuticle of Scapteriscus didactylus. The isotopic signature was compared between individuals collected at two sites: a village where mole crickets fed on human food scraps and the nearby Awala-Yalimapo beach, where food availability depends seasonally on the nesting sea turtles. The mole crickets collected near the habitations garbage showed no significant variations in the stable isotopic signature, within-and between age groups. On the contrary, isotopic values shifted from a signature of a terrestrial herbivorous diet in the mole crickets during early developmental stages, to isotopic values in adults in accordance with the exploitation of marine animal resources. Conclusion The heterogeneity of individual signatures during the year is due to a selective exploitation of the food sources

  16. 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.

  17. 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.

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

    Science.gov (United States)

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

    2016-07-01

    Biological control using microbial antagonists is a promising alternative approach to synthetic fungicides. However, effective biological control requires enhancing the consistency and efficacy of the antagonists used to control postharvest diseases. This study investigated the effect of chitin on the biocontrol efficacy of Rhodotorula mucilaginosa against blue mold and Rhizopus decay of peaches and on the protein expression profiles of R. mucilaginosa. The antagonistic activity of R. mucilaginosa harvested from the nutrient yeast dextrose broth (NYDB) with 0.5% chitin added was significantly improved compared with culture in NYDB without chitin. The R. mucilaginosa population cultured in chitin-supplement NYDB and nutrient yeast chitin borth (NYCB) harvested from peach wounds was more than that of R. mucilaginosa cultured in NYDB without chitin throughout the storage period except at 1 d. The protein expression profiles findings revealed that there were several differentially expressed proteins of R. mucilaginosa in the 0.5% chitin-supplemented NYDB and NYCB compared with that of R. mucilaginosa in NYDB. Most of these were cellular proteomes relating to the primary metabolic reactions such as glycoside hydrolases, phosphoribosyl pyrophosphate, and NADH dehydrogenases. Some proteins were also related to signal transmission and stress response. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Surface modification of chitin and chitosan with poly(3-hexylthiophene) via oxidative polymerization

    Science.gov (United States)

    Hai, Thien An Phung; Sugimoto, Ryuichi

    2018-03-01

    In the present work, the modification of biomaterials such as chitin and chitosan were successfully prepared by directly grafting poly(3-hexylthiophene) (P3HT) to their surfaces using simple oxidative polymerization with FeCl3. The thermal stability and crystallinity of grafted chitin and chitosan changed upon grafting with P3HT. The build-up of π-π* structure from the P3HT on the surface of chitin and chitosan resulted in the appearance of UV-vis absorption and fluorescence emission peaks in the range from 500 to 600 nm. Introducing P3HT to the surface of chitin and chitosan improved significantly the electrical property of chitin and chitosan with the increase in conductivity from 10-9 to 10-7 S/cm. Furthermore, the usual behavior of hydrophilic surface of chitin and chitosan that turned to hydrophobic with water contact angle of 97.7° and 107.0°, respectively in the presence of P3HT. The mechanism for graft reaction of P3HT to chitin and chitosan was also proposed and discussed.

  20. An integrated theoretical and experimental investigation of insensitive munition compounds adsorption on cellulose, cellulose triacetate, chitin and chitosan surfaces.

    Science.gov (United States)

    Gurtowski, Luke A; Griggs, Chris S; Gude, Veera G; Shukla, Manoj K

    2018-02-01

    This manuscript reports results of combined computational chemistry and batch adsorption investigation of insensitive munition compounds, 2,4-dinitroanisole (DNAN), triaminotrinitrobenzene (TATB), 1,1-diamino-2,2-dinitroethene (FOX-7) and nitroguanidine (NQ), and traditional munition compound 2,4,6-trinitrotoluene (TNT) on the surfaces of cellulose, cellulose triacetate, chitin and chitosan biopolymers. Cellulose, cellulose triacetate, chitin and chitosan were modeled as trimeric form of the linear chain of 4 C 1 chair conformation of β-d-glucopyranos, its triacetate form, β-N-acetylglucosamine and D-glucosamine, respectively, in the 1➔4 linkage. Geometries were optimized at the M062X functional level of the density functional theory (DFT) using the 6-31G(d,p) basis set in the gas phase and in the bulk water solution using the conductor-like polarizable continuum model (CPCM) approach. The nature of potential energy surfaces of the optimized geometries were ascertained through the harmonic vibrational frequency analysis. The basis set superposition error (BSSE) corrected interaction energies were obtained using the 6-311G(d,p) basis set at the same theoretical level. The computed BSSE in the gas phase was used to correct interaction energy in the bulk water solution. Computed and experimental results regarding the ability of considered surfaces in adsorbing the insensitive munitions compounds are discussed. Copyright © 2017. Published by Elsevier B.V.

  1. Surface modification of chitin using ultrasound-assisted and supercritical CO{sub 2} technologies for cobalt adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Dotto, Guilherme L., E-mail: guilherme_dotto@yahoo.com.br; Cunha, Jeanine M., E-mail: jeaninecunha@gmail.com; Calgaro, Camila O., E-mail: camila.itepjr@gmail.com; Tanabe, Eduardo H., E-mail: edutanabe@yahoo.com.br; Bertuol, Daniel A., E-mail: dbertuol@gmail.com

    2015-09-15

    Highlights: • Chitin was modified by ultrasound-assisted (UA) and supercritical (SCO{sub 2}) technologies. • Chitin, UA-chitin and SCO{sub 2}-chitin were used as adsorbents for Co(II). • UA and SCO{sub 2} treatments provided increase of 20 and 3 times in chitin surface area. • The Co(II) adsorption capacity increased until 67.8%, using UA-chitin. - Abstract: Ultrasound-assisted (UA) and supercritical CO{sub 2} technologies (SCO{sub 2}) were used to modify the chitin surface and, improve its adsorption characteristics regarding to cobalt. Chitin, before and after the treatments, was characterized by N{sub 2} adsorption isotherms (BET), infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). Unmodified and surface modified chitins were used as adsorbents to remove cobalt from aqueous solutions. The adsorption study was performed by equilibrium isotherms and kinetic curves. The chitin particle characteristics, such as, surface area, pore volume and porosity were improved by the UA and SCO{sub 2} treatments. The crystallinity index decreased after the UA and SCO{sub 2} treatments, and also, intense surface modifications were observed. Langmuir and Freundlich models were adequate to represent the adsorption equilibrium. The maximum adsorption capacities were 50.03, 83.94 and 63.08 mg g{sup −1} for unmodified chitin, UA surface modified chitin and SCO{sub 2} surface modified chitin. The adsorption kinetic curves were well represented by the pseudo-second order model. UA and SCO{sub 2} technologies are alternatives to modify the chitin surface and improve its adsorption characteristics.

  2. Mechanical properties of the cuticles of three cockroach species that differ in their wind-evoked escape behavior

    Directory of Open Access Journals (Sweden)

    Andrew J. Clark

    2014-07-01

    Full Text Available The structural and material properties of insect cuticle remain largely unexplored, even though they comprise the majority (approximately 80% of animals. Insect cuticle serves many functions, including protection against predatory attacks, which is especially beneficial to species failing to employ effective running escape responses. Despite recent advances in our understanding of insect escape behaviors and the biomechanics of insect cuticle, there are limited studies on the protective qualities of cuticle to extreme mechanical stresses and strains imposed by predatory attacks, and how these qualities vary between species employing different escape responses. Blattarians (cockroaches provide an appropriate model system for such studies. Wind-evoked running escape responses are strong in Periplaneta americana, weak in Blaberus craniifer and absent in Gromphodorhina portentosa, putting the latter two species at greater risk of being struck by a predator. We hypothesized that the exoskeletons in these two larger species could provide more protection from predatory strikes relative to the exoskeleton of P. americana. We quantified the protective qualities of the exoskeletons by measuring the puncture resistance, tensile strength, strain energy storage, and peak strain in fresh samples of thoracic and abdominal cuticles from these three species. We found a continuum in puncture resistance, tensile strength, and strain energy storage between the three species, which were greatest in G. portentosa, moderate in B. craniifer, and smallest in P. americana. Histological measurements of total cuticle thickness followed this same pattern. However, peak strain followed a different trend between species. The comparisons in the material properties drawn between the cuticles of G. portentosa, B. craniifer, and P. americana demonstrate parallels between cuticular biomechanics and predator running escape responses.

  3. RNAi-Mediated Functional Analysis of Bursicon Genes Related to Adult Cuticle Formation and Tanning in the Honeybee, Apis mellifera.

    Directory of Open Access Journals (Sweden)

    Claudinéia Pereira Costa

    Full Text Available Bursicon is a heterodimeric neurohormone that acts through a G protein-coupled receptor named rickets (rk, thus inducing an increase in cAMP and the activation of tyrosine hydroxylase, the rate-limiting enzyme in the cuticular tanning pathway. In insects, the role of bursicon in the post-ecdysial tanning of the adult cuticle and wing expansion is well characterized. Here we investigated the roles of the genes encoding the bursicon subunits during the adult cuticle development in the honeybee, Apis mellifera. RNAi-mediated knockdown of AmBurs α and AmBurs β bursicon genes prevented the complete formation and tanning (melanization/sclerotization of the adult cuticle. A thinner, much less tanned cuticle was produced, and ecdysis toward adult stage was impaired. Consistent with these results, the knockdown of bursicon transcripts also interfered in the expression of genes encoding its receptor, AmRk, structural cuticular proteins, and enzymes in the melanization/sclerotization pathway, thus evidencing roles for bursicon in adult cuticle formation and tanning. Moreover, the expression of AmBurs α, AmBurs β and AmRk is contingent on the declining ecdysteroid titer that triggers the onset of adult cuticle synthesis and deposition. The search for transcripts of AmBurs α, AmBurs β and candidate targets in RNA-seq libraries prepared with brains and integuments strengthened our data on transcript quantification through RT-qPCR. Together, our results support our premise that bursicon has roles in adult cuticle formation and tanning, and are in agreement with other recent studies pointing for roles during the pharate-adult stage, in addition to the classical post-ecdysial ones.

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

    Directory of Open Access Journals (Sweden)

    Riccardo A. A. Muzzarelli

    2010-02-01

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

  5. 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

  6. Characterization of a plant leaf cuticle model wax, phase behaviour of model wax–water systems

    International Nuclear Information System (INIS)

    Fagerström, Anton; Kocherbitov, Vitaly; Westbye, Peter; Bergström, Karin; Mamontova, Varvara; Engblom, Johan

    2013-01-01

    Highlights: • Four individual crystalline phases were discovered in the model wax–water system. • Eutectic melting occurred in both dry and hydrated model wax. • The total transition enthalpy is smaller for the cuticle wax than for the model wax. • Water has a large plasticizing effect on cuticle wax. • The thermotropic transitions of model wax fit in the window of extracted leaf waxes. - Abstract: We investigated the thermotropic phase behaviour of plant leaf intracuticular wax and two representatives of its main components, 1-docosanol (C 22 H 45 OH) and dotriacontane (C 32 H 66 ), in dry and hydrated state. One objective was to obtain a model wax, which can be used to estimate formulations effects on cuticle diffusivity in vitro. The two wax components were chosen based on results from Gas Chromatography coupled to Mass Spectrometry analysis of cuticular wax. The wax was extracted from Clivia Miniata Regel leaves and contained 68% primary alcohols (C 16 –C 32 ) and 16% n-alkanes (C 21 –C 33 ). Differential Scanning Calorimetry, Polarized Light Microscopy and Small- and Wide Angle X-ray Diffraction were used to characterize the cuticular extract and the phase behaviour of the C 22 H 45 OH/C 32 H 66 /H 2 O model system. Four individual crystalline phases were discovered in the model wax–water system and eutectic melting occurred in both dry and hydrated state. The thermotropic transitions of the model wax occur within the broader transition region of the extracted leaf wax

  7. Characterization of a plant leaf cuticle model wax, phase behaviour of model wax–water systems

    Energy Technology Data Exchange (ETDEWEB)

    Fagerström, Anton, E-mail: anton.fagerstrom@mah.se [Biomedical Science, Faculty of Health and Society, Malmö University, Malmö (Sweden); Kocherbitov, Vitaly [Biomedical Science, Faculty of Health and Society, Malmö University, Malmö (Sweden); Westbye, Peter; Bergström, Karin [Agro Applications Europe, AkzoNobel Surface Chemistry AB, Stenungsund (Sweden); Mamontova, Varvara [Ecological and Chemical Research, St. Petersburg Scientific Research Center for Ecological Safety, Russian Academy of Sciences, St. Petersburg (Russian Federation); Engblom, Johan [Biomedical Science, Faculty of Health and Society, Malmö University, Malmö (Sweden)

    2013-11-10

    Highlights: • Four individual crystalline phases were discovered in the model wax–water system. • Eutectic melting occurred in both dry and hydrated model wax. • The total transition enthalpy is smaller for the cuticle wax than for the model wax. • Water has a large plasticizing effect on cuticle wax. • The thermotropic transitions of model wax fit in the window of extracted leaf waxes. - Abstract: We investigated the thermotropic phase behaviour of plant leaf intracuticular wax and two representatives of its main components, 1-docosanol (C{sub 22}H{sub 45}OH) and dotriacontane (C{sub 32}H{sub 66}), in dry and hydrated state. One objective was to obtain a model wax, which can be used to estimate formulations effects on cuticle diffusivity in vitro. The two wax components were chosen based on results from Gas Chromatography coupled to Mass Spectrometry analysis of cuticular wax. The wax was extracted from Clivia Miniata Regel leaves and contained 68% primary alcohols (C{sub 16}–C{sub 32}) and 16% n-alkanes (C{sub 21}–C{sub 33}). Differential Scanning Calorimetry, Polarized Light Microscopy and Small- and Wide Angle X-ray Diffraction were used to characterize the cuticular extract and the phase behaviour of the C{sub 22}H{sub 45}OH/C{sub 32}H{sub 66}/H{sub 2}O model system. Four individual crystalline phases were discovered in the model wax–water system and eutectic melting occurred in both dry and hydrated state. The thermotropic transitions of the model wax occur within the broader transition region of the extracted leaf wax.

  8. 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

  9. Cosmetics and Cosmeceutical Applications of Chitin, Chitosan and Their Derivatives

    Directory of Open Access Journals (Sweden)

    Inmaculada Aranaz

    2018-02-01

    Full Text Available Marine resources are well recognized for their biologically active substances with great potential applications in the cosmeceutical industry. Among the different compounds with a marine origin, chitin and its deacetylated derivative—chitosan—are of great interest to the cosmeceutical industry due to their unique biological and technological properties. In this review, we explore the different functional roles of chitosan as a skin care and hair care ingredient, as an oral hygiene agent and as a carrier for active compounds, among others. The importance of the physico-chemical properties of the polymer in its use in cosmetics are particularly highlighted. Moreover, we analyse the market perspectives of this polymer and the presence in the market of chitosan-based products.

  10. 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.

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

    Science.gov (United States)

    Rodriguez, Isaac A.; Sell, Scott A.; McCool, Jennifer M.; Saxena, Gunjan; Spence, Andrew J.; Bowlin, Gary L.

    2013-01-01

    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. PMID:24709699

  12. 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.

  13. Chitin biological absorbable catheters bridging sural nerve grafts transplanted into sciatic nerve defects promote nerve regeneration.

    Science.gov (United States)

    Wang, Zhi-Yong; Wang, Jian-Wei; Qin, Li-Hua; Zhang, Wei-Guang; Zhang, Pei-Xun; Jiang, Bao-Guo

    2018-06-01

    To investigate the efficacy of chitin biological absorbable catheters in a rat model of autologous nerve transplantation. A segment of sciatic nerve was removed to produce a sciatic nerve defect, and the sural nerve was cut from the ipsilateral leg and used as a graft to bridge the defect, with or without use of a chitin biological absorbable catheter surrounding the graft. The number and morphology of regenerating myelinated fibers, nerve conduction velocity, nerve function index, triceps surae muscle morphology, and sensory function were evaluated at 9 and 12 months after surgery. All of the above parameters were improved in rats in which the nerve graft was bridged with chitin biological absorbable catheters compared with rats without catheters. The results of this study indicate that use of chitin biological absorbable catheters to surround sural nerve grafts bridging sciatic nerve defects promotes recovery of structural, motor, and sensory function and improves muscle fiber morphology. © 2018 John Wiley & Sons Ltd.

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

    International Nuclear Information System (INIS)

    Li Xiaoming; Feng Qingling; Cui Fuzhai

    2006-01-01

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

  15. Solid state characterization of α-chitin from Vanessa cardui Linnaeus wings

    International Nuclear Information System (INIS)

    Schiffman, Jessica D.; Schauer, Caroline L.

    2009-01-01

    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 (α-chitin) and squid pens from Notodarus sloanii and Loligo pealei (β-chitin). Fourier transmission infrared spectroscopy (FTIR) and X-ray diffraction (XRD) revealed that the painted lady butterflies are composed of α-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.

  16. 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.

  17. Application of chitin and zeolite adsorbents for treatment of low level radioactive liquid wastes

    International Nuclear Information System (INIS)

    Moattar, F.; Hayeripour, S.

    2004-01-01

    Two types of shrimp chitin derivatives and two types of Iranian natural zeolite derivates were studied for adsorption and treatment of low-level radioactive liquid waste. Chitin with lowers than 10% and chitosan with higher than 90% deacetylation factor were selected as neutral organic adsorbents. Natural clinoptilolite of Firuzkooh area and Na from derivates of it were selected as natural inorganic adsorbents. The static and dynamic ion exchange experimental results show that the ad adsorption efficiency depend on particle size, Ph, adsorbent type, deacetylation factor ( in chitin adsorbents) and cation type. The best Cs adsorption occurred in Na from clinoptilolite. Nevertheless chitin derivatives, particularly chitosan, are more efficient than zeolite adsorbents for removing of radionuclides such as 137 Cs, 54 Mn, 90 Sr and 60 Co. Adsorption performance was discussed and compared with each other

  18. Preparation of metal adsorbents from chitin/chitosan by radiation technology

    International Nuclear Information System (INIS)

    Nguyen Van Suc; Nguyen Quoc Hien; Ngo Quang Huy; Thai My Phe; Dao Van Hoang; Nguyen Van Hung

    2004-01-01

    The methods of preparation of metal adsorbents basing on chitin/chitosan were developed. That include the adsorbent from chitin grafted with acrylic acid by different irradiation doses; the clinging chitosan gel beads; the coagulable solution and the chitosan composite filter. The process of metal adsorption for each adsorbent was studied as adsorption kinetic, isothermal adsorption. The results have been applied for removal of some elements as Hg, Pb, Cd, U, Cu, ect. in the wastewater. (NHA)

  19. Chitin-induced T6SS in Vibrio cholerae is dependent on ChiS activation.

    Science.gov (United States)

    Chourashi, Rhishita; Das, Suman; Dhar, Debarpan; Okamoto, Keinosuke; Mukhopadhyay, Asish K; Chatterjee, Nabendu Sekhar

    2018-05-01

    Vibrio cholerae regularly colonizes the chitinous exoskeleton of crustacean shells in the aquatic region. The type 6 secretion system (T6SS) in V. cholerae is an interbacterial killing device. This system is thought to provide a competitive advantage to V. cholerae in a polymicrobial community of the aquatic region under nutrient-poor conditions. V. cholerae chitin sensing is known to be initiated by the activation of a two-component sensor histidine kinase ChiS in the presence of GlcNAc2 (N,N'-diacetylchitobiose) residues generated by the action of chitinases on chitin. It is known that T6SS in V. cholerae is generally induced by chitin. However, the effect of ChiS activation on T6SS is unknown. Here, we found that ChiS inactivation resulted in impaired bacterial killing and reduced expression of T6SS genes. Active ChiS positively affected T6SS-mediated natural transformation in V. cholerae. ChiS depletion or inactivation also resulted in reduced colonization on insoluble chitin surfaces. Therefore, we have shown that V. cholerae colonization on chitinous surfaces activates ChiS, which promotes T6SS-dependent bacterial killing and horizontal gene transfer. We also highlight the importance of chitinases in T6SS upregulation.

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

    Science.gov (United States)

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

    2015-06-18

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

  1. Squid-derived chitin oligosaccharides are a chemotactic signal during colonization by Vibrio fischeri.

    Science.gov (United States)

    Mandel, Mark J; Schaefer, Amy L; Brennan, Caitlin A; Heath-Heckman, Elizabeth A C; Deloney-Marino, Cindy R; McFall-Ngai, Margaret J; Ruby, Edward G

    2012-07-01

    Chitin, a polymer of N-acetylglucosamine (GlcNAc), is noted as the second most abundant biopolymer in nature. Chitin serves many functions for marine bacteria in the family Vibrionaceae ("vibrios"), in some instances providing a physical attachment site, inducing natural genetic competence, and serving as an attractant for chemotaxis. The marine luminous bacterium Vibrio fischeri is the specific symbiont in the light-emitting organ of the Hawaiian bobtail squid, Euprymna scolopes. The bacterium provides the squid with luminescence that the animal uses in an antipredatory defense, while the squid supports the symbiont's nutritional requirements. V. fischeri cells are harvested from seawater during each host generation, and V. fischeri is the only species that can complete this process in nature. Furthermore, chitin is located in squid hemocytes and plays a nutritional role in the symbiosis. We demonstrate here that chitin oligosaccharides produced by the squid host serve as a chemotactic signal for colonizing bacteria. V. fischeri uses the gradient of host chitin to enter the squid light organ duct and colonize the animal. We provide evidence that chitin serves a novel function in an animal-bacterial mutualism, as an animal-produced bacterium-attracting synomone.

  2. Cuticle expansion during feeding in the tick Amblyomma hebraeum (Acari: Ixodidae): The role of hydrostatic pressure.

    Science.gov (United States)

    Kaufman, W Reuben; Kaufman, S; Flynn, Peter C

    2016-05-01

    Female Amblyomma hebraeum ticks (Acari: Ixodidae) increase their weight ∼10-fold during a 'slow phase of engorgement' (7-9 days), and a further 10-fold during the 'rapid phase' (12-24h). During the rapid phase, the cuticle thins by half, with a plastic (permanent) deformation of greater than 40% in two orthogonal directions. A stress of 2.5 MPa or higher is required to achieve this degree of deformation (Flynn and Kaufman, 2015). Using a dimensional analysis of the tick body and applying the Laplace equation, we calculated that the tick must achieve high internal hydrostatic pressures in order to engorge fully: greater than 55 kPa at a fed:unfed mass ratio of ∼20:1, when cuticle thinning commences (Flynn and Kaufman, 2011). In this study we used a telemetric pressure transducer system to measure the internal hydrostatic pressure of ticks during feeding. Sustained periods of irregular high frequency (>20 Hz) pulsatile bursts of high pressure (>55 kPa) were observed in two ticks: they had been cannulated just prior to the rapid phase of engorgement, and given access to a host rabbit for completion of the feeding cycle. The pattern of periods of high pressure generation varied over the feeding cycle and between the two specimens. We believe that these pressures exceed those reported so far for any other animal. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. 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...

  4. Identification and first insights into the structure and biosynthesis of chitin from the freshwater sponge Spongilla lacustris.

    Science.gov (United States)

    Ehrlich, Hermann; Kaluzhnaya, Oksana V; Brunner, Eike; Tsurkan, Mikhail V; Ereskovsky, Alexander; Ilan, Micha; Tabachnick, Konstantin R; Bazhenov, Vasilii V; Paasch, Silvia; Kammer, Martin; Born, René; Stelling, Allison; Galli, Roberta; Belikov, Sergei; Petrova, Olga V; Sivkov, Victor V; Vyalikh, Denis; Hunoldt, Sebastian; Wörheide, Gert

    2013-09-01

    This work demonstrates that chitin is an important structural component within the skeletal fibers of the freshwater sponge Spongilla lacustris. Using a variety of analytical techniques ((13)C solid state NMR, FT-IR, Raman, NEXAFS, ESI-MS, Morgan-Elson assay and Calcofluor White Staining); we show that this sponge chitin is much closer to α-chitin, known to be present in other animals, than to β-chitin. Genetic analysis confirmed the presence of chitin synthases, which are described for the first time in a sponge. The presence of chitin in both marine (demosponges and hexactinellids) and freshwater sponges indicates that this important structural biopolymer was already present in their common ancestor. Copyright © 2013 Elsevier Inc. All rights reserved.

  5. The effect of metapleural gland secretion on the growth of a mutualistic bacterium on the cuticle of leaf-cutting ants

    DEFF Research Database (Denmark)

    Poulsen, Michael; Bot, Adrianne N M; Boomsma, Jacobus J

    2003-01-01

    In Acromyrmex octospinosus leaf-cutting ants the metapleural glands produce an array of antibiotic compounds that serve as a general defence against unwanted microbes on the cuticle. Leaf-cutting ants also grow mutualistic Pseudonocardiaceae bacteria on their cuticle that produce antibiotics...

  6. The hard parts (trophi) of the rotifer mastax do contain chitin: evidence from studies on Brachionus plicatilis.

    Science.gov (United States)

    Klusemann, J; Kleinow, W; Peters, W

    1990-01-01

    The jaws (trophi) of the rotifer Brachionus plicatilis are soluble in strong acids but are resistant to long treatments by strong alkali. They show the same buoyant density as chitin and also as the chitin-containing layers of rotifer egg-shells. The presence of chitin in these structures was confirmed using the following techniques: chitosan-tests, thin-layer chromatography of trophi-hydrolysates which revealed glucosamine, by dissolving trophi with chitinase and electron microscopic WGA/gold-labelling. The content of chitin in the trophi was estimated by two different methods to be approx. 64% (50-75%).

  7. A Novel, Extremely Elongated, and Endocellular Bacterial Symbiont Supports Cuticle Formation of a Grain Pest Beetle.

    Science.gov (United States)

    Hirota, Bin; Okude, Genta; Anbutsu, Hisashi; Futahashi, Ryo; Moriyama, Minoru; Meng, Xian-Ying; Nikoh, Naruo; Koga, Ryuichi; Fukatsu, Takema

    2017-09-26

    The saw-toothed grain beetle, Oryzaephilus surinamensis (Silvanidae), is a cosmopolitan stored-product pest. Early studies on O. surinamensis in the 1930s described the presence of peculiar bacteriomes harboring endosymbiotic bacteria in the abdomen. Since then, however, the microbiological nature of the symbiont has been elusive. Here we investigated the endosymbiotic system of O. surinamensis in detail. In the abdomen of adults, pupae, and larvae, four oval bacteriomes were consistently identified, whose cytoplasm was full of extremely elongated tubular bacterial cells several micrometers wide and several hundred micrometers long. Molecular phylogenetic analysis identified the symbiont as a member of the Bacteroidetes , in which the symbiont was the most closely related to the endosymbiont of a grain pest beetle, Rhyzopertha dominica (Bostrichidae). The symbiont was detected in developing embryos, corroborating vertical symbiont transmission through host generations. The symbiont gene showed AT-biased nucleotide composition and accelerated molecular evolution, plausibly reflecting degenerative evolution of the symbiont genome. When the symbiont infection was experimentally removed, the aposymbiotic insects grew and reproduced normally, but exhibited a slightly but significantly more reddish cuticle and lighter body mass. These results indicate that the symbiont of O. surinamensis is not essential for the host's growth and reproduction but contributes to the host's cuticle formation. Symbiont genome sequencing and detailed comparison of fitness parameters between symbiotic and aposymbiotic insects under various environmental conditions will provide further insights into the symbiont's biological roles for the stored-product pest. IMPORTANCE Some beetles notorious as stored-product pests possess well-developed symbiotic organs called bacteriomes for harboring specific symbiotic bacteria, although their biological roles have been poorly understood. Here we report

  8. First Report on Chitin in a Non-Verongiid Marine Demosponge: The Mycale euplectellioides Case.

    Science.gov (United States)

    Żółtowska-Aksamitowska, Sonia; Shaala, Lamiaa A; Youssef, Diaa T A; Elhady, Sameh S; Tsurkan, Mikhail V; Petrenko, Iaroslav; Wysokowski, Marcin; Tabachnick, Konstantin; Meissner, Heike; Ivanenko, Viatcheslav N; Bechmann, Nicole; Joseph, Yvonne; Jesionowski, Teofil; Ehrlich, Hermann

    2018-02-20

    Sponges (Porifera) are recognized as aquatic multicellular organisms which developed an effective biochemical pathway over millions of years of evolution to produce both biologically active secondary metabolites and biopolymer-based skeletal structures. Among marine demosponges, only representatives of the Verongiida order are known to synthetize biologically active substances as well as skeletons made of structural polysaccharide chitin. The unique three-dimensional (3D) architecture of such chitinous skeletons opens the widow for their recent applications as adsorbents, as well as scaffolds for tissue engineering and biomimetics. This study has the ambitious goal of monitoring other orders beyond Verongiida demosponges and finding alternative sources of naturally prestructured chitinous scaffolds; especially in those demosponge species which can be cultivated at large scales using marine farming conditions. Special attention has been paid to the demosponge Mycale euplectellioides (Heteroscleromorpha: Poecilosclerida: Mycalidae) collected in the Red Sea. For the first time, we present here a detailed study of the isolation of chitin from the skeleton of this sponge, as well as its identification using diverse bioanalytical tools. Calcofluor white staining, Fourier-transform Infrared Spcetcroscopy (FTIR), electrospray ionization mass spectrometry (ESI-MS), scanning electron microscopy (SEM), and fluorescence microscopy, as well as a chitinase digestion assay were applied in order to confirm with strong evidence the finding of a-chitin in the skeleton of M. euplectellioides . We suggest that the discovery of chitin within representatives of the Mycale genus is a promising step in their evaluation of these globally distributed sponges as new renewable sources for both biologically active metabolites and chitin, which are of prospective use for pharmacology and biomaterials oriented biomedicine, respectively.

  9. First Report on Chitin in a Non-Verongiid Marine Demosponge: The Mycale euplectellioides Case

    Directory of Open Access Journals (Sweden)

    Sonia Żółtowska-Aksamitowska

    2018-02-01

    Full Text Available Sponges (Porifera are recognized as aquatic multicellular organisms which developed an effective biochemical pathway over millions of years of evolution to produce both biologically active secondary metabolites and biopolymer-based skeletal structures. Among marine demosponges, only representatives of the Verongiida order are known to synthetize biologically active substances as well as skeletons made of structural polysaccharide chitin. The unique three-dimensional (3D architecture of such chitinous skeletons opens the widow for their recent applications as adsorbents, as well as scaffolds for tissue engineering and biomimetics. This study has the ambitious goal of monitoring other orders beyond Verongiida demosponges and finding alternative sources of naturally prestructured chitinous scaffolds; especially in those demosponge species which can be cultivated at large scales using marine farming conditions. Special attention has been paid to the demosponge Mycale euplectellioides (Heteroscleromorpha: Poecilosclerida: Mycalidae collected in the Red Sea. For the first time, we present here a detailed study of the isolation of chitin from the skeleton of this sponge, as well as its identification using diverse bioanalytical tools. Calcofluor white staining, Fourier-transform Infrared Spcetcroscopy (FTIR, electrospray ionization mass spectrometry (ESI-MS, scanning electron microscopy (SEM, and fluorescence microscopy, as well as a chitinase digestion assay were applied in order to confirm with strong evidence the finding of a-chitin in the skeleton of M. euplectellioides. We suggest that the discovery of chitin within representatives of the Mycale genus is a promising step in their evaluation of these globally distributed sponges as new renewable sources for both biologically active metabolites and chitin, which are of prospective use for pharmacology and biomaterials oriented biomedicine, respectively.

  10. Study of Zn, Cd, and Pb Adsorption Using Chitin Extracted from Lobsters from Oman Sea

    Directory of Open Access Journals (Sweden)

    Alireza Sardashti

    2015-10-01

    Full Text Available Lobster shells from Konarak Port were collected in October 2002, purified, and dried for the purposes of the present study. Chitin was extracted from the shellsusing the common chemical processes of demineralization, proteinzation, and decolonization, beforepurificationwith 1% CH3COOH and 1% NaCl to obatin an extract containing 12% (w/w chitin. Chitin composition was determined using FT-IR, X-Ray powder diffraction, BET, and C.H.N.S analysis. The FT-IR spectrum of the extracted chitin was corresponded well to the Merck standard one, indicating that it is a linear polymer of N-acetyl-D- glucosamine on which metal ions can be adsorbed. Kinetic study of chitin’s reaction with Zn+2 at pH=6.75 and an ionic strength of 0.02 M indicated that adsorption equilibrium was reached within six hours of mixing. Adsorption Langmuir isotherms for a solution of Zn+2, Cd+2, and Pb+2 ions at an initial concentration of 2×10‒3 M were determined for an ionic strenght of 0.02 M, different pH levels, and at ambient temparature using the discontinued in-pot method. The maximum amounts of metal ions adsorbed on chitin at pH= 6.75 were measured to be 0.119 mol/kg for Cd+2, 0.714 mol/kg for Zn+2, and 1.630 mol/Kg for Pb+2. The overdyeing graphs, Cs= f (pH, show that the adsorption capacity of chitin is influenced by such factors as pH, reaction time, metal ion concantration, and adsorbent particle size. Thus, chitin as a non-toxic natural polymer may be highly recommended for water detoxification from heavy metal ions.

  11. Two very long chain fatty acid acyl-CoA synthetase genes, acs-20 and acs-22, have roles in the cuticle surface barrier in Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Eriko Kage-Nakadai

    Full Text Available In multicellular organisms, the surface barrier is essential for maintaining the internal environment. In mammals, the barrier is the stratum corneum. Fatty acid transport protein 4 (FATP4 is a key factor involved in forming the stratum corneum barrier. Mice lacking Fatp4 display early neonatal lethality with features such as tight, thick, and shiny skin, and a defective skin barrier. These symptoms are strikingly similar to those of a human skin disease called restrictive dermopathy. FATP4 is a member of the FATP family that possesses acyl-CoA synthetase activity for very long chain fatty acids. How Fatp4 contributes to skin barrier function, however, remains to be elucidated. In the present study, we characterized two Caenorhabditis elegans genes, acs-20 and acs-22, that are homologous to mammalian FATPs. Animals with mutant acs-20 exhibited defects in the cuticle barrier, which normally prevents the penetration of small molecules. acs-20 mutant animals also exhibited abnormalities in the cuticle structure, but not in epidermal cell fate or cell integrity. The acs-22 mutants rarely showed a barrier defect, whereas acs-20;acs-22 double mutants had severely disrupted barrier function. Moreover, the barrier defects of acs-20 and acs-20;acs-22 mutants were rescued by acs-20, acs-22, or human Fatp4 transgenes. We further demonstrated that the incorporation of exogenous very long chain fatty acids into sphingomyelin was reduced in acs-20 and acs-22 mutants. These findings indicate that C. elegans Fatp4 homologue(s have a crucial role in the surface barrier function and this model might be useful for studying the fundamental molecular mechanisms underlying human skin barrier and relevant diseases.

  12. Deciphering the Evolution and Development of the Cuticle by Studying Lipid Transfer Proteins in Mosses and Liverworts

    Directory of Open Access Journals (Sweden)

    Tiina A. Salminen

    2018-01-01

    Full Text Available When plants conquered land, they developed specialized organs, tissues, and cells in order to survive in this new and harsh terrestrial environment. New cell polymers such as the hydrophobic lipid-based polyesters cutin, suberin, and sporopollenin were also developed for protection against water loss, radiation, and other potentially harmful abiotic factors. Cutin and waxes are the main components of the cuticle, which is the waterproof layer covering the epidermis of many aerial organs of land plants. Although the in vivo functions of the group of lipid binding proteins known as lipid transfer proteins (LTPs are still rather unclear, there is accumulating evidence suggesting a role for LTPs in the transfer and deposition of monomers required for cuticle assembly. In this review, we first present an overview of the data connecting LTPs with cuticle synthesis. Furthermore, we propose liverworts and mosses as attractive model systems for revealing the specific function and activity of LTPs in the biosynthesis and evolution of the plant cuticle.

  13. Hornet cuticle - a composite structure comprised of a series of duplex lamellae attenuating toward the interior of the body

    NARCIS (Netherlands)

    Ishay, JS; Kirshboim, S; Steinberg, D; Kalicharan, D; Jongebloed, WL

    Our study deals with the ultramicroscopic structure of the yellow pigmented cuticular stripes on the abdomen of the oriental hornet Vespa orientalis (Hymenoptera, Vespinae). The abdominal cuticle is composed of numerous (more than 25) lamellae which progressively attenuate as one proceeds from the

  14. Characteristic properties of proteins from pre-ecdysial cuticle of larvae and pupae of the mealworm Tenebrio molitor

    DEFF Research Database (Denmark)

    Andersen, Svend Olav

    2002-01-01

    Proteins extracted from the cuticle of pharate larvae and pupae of the mealworm Tenebrio molitor are more soluble at low temperatures than at higher temperatures, a behaviour characteristic of hydrophobic proteins. When the temperature of an unfractionated cuticular extract is raised from 4 to 25...... undergo plasticization during and/or immediately after ecdysis....

  15. Chitin Fiber and Chitosan 3D Composite Rods

    International Nuclear Information System (INIS)

    Wang, Z.; Hu, Q.; Cai, L.

    2010-01-01

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

  16. Chitin butyrate coated electrospun nylon-6 fibers for biomedical applications

    Science.gov (United States)

    Pant, Hem Raj; Kim, Han Joo; Bhatt, Lok Ranjan; Joshi, Mahesh Kumar; Kim, Eun Kyo; Kim, Jeong In; Abdal-hay, Abdalla; Hui, K. S.; Kim, Cheol Sang

    2013-11-01

    In this study, we describe the preparation and characterizations of chitin butyrate (CB) coated nylon-6 nanofibers using single-spinneret electrospinning of blends solution. The physicochemical properties of nylon-6 composite fibers with different proportions of CB to nylon-6 were determined using FE-SEM, TEM, FT-IR spectroscopy, and water contact angle measurement. FE-SEM and TEM images revealed that the nylon-6 and CB were immiscible in the as-spun nanofibers, and phase separated nanofiber morphology becomes more pronounced with increasing amounts of CB. The bone formation ability of composite fibers was evaluated by incubating in biomimetic simulated body fluid. In order to assay the cytocompatibility and cell behavior on the composite scaffolds, osteoblast cells were seeded on the matrix. Results suggest that the deposition of CB layer on the surface of nylon-6 could increase its cell compatibility and bone formation ability. Therefore, as-synthesized nanocomposite fibrous mat has great potentiality in hard tissue engineering.

  17. Chitin Fiber and Chitosan 3D Composite Rods

    Directory of Open Access Journals (Sweden)

    Zhengke Wang

    2010-01-01

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

  18. Effects of buprofezin on the ultrastructure of the third instar cuticle of the insect Trialeurodes vaporariorum.

    Science.gov (United States)

    De Cock, A; Degheele, D

    1991-01-01

    Treatment with buprofezin at the beginning of the third instar of Trialeurodes vaporariorum results in death of the larvae at the time of moulting. Electron microscopic observations, after treatment of the larvae with 20 mg a.i./l buprofezin, does not reveal any difference in the ultrastructural profile before apolysis, however formation of a normal lamellate procuticle is disturbed. The pharate procuticle is amorphous, varying in thickness and the mean thickness is greatly reduced. The subcuticle is interrupted several times at locations corresponding with the thinnest places of the pharate cuticle. Epidermal cells contain unusual structures such as myelin figures and hypertrophied mitochondria indicating that buprofezin may have an additional toxic effect on epidermal cells.

  19. Arabidopsis ECERIFERUM9 involvement in cuticle formation and maintenance of plant water status

    KAUST Repository

    Lu, Shiyou

    2012-05-25

    Mutation of the ECERIFERUM9 (CER9) gene in Arabidopsis (Arabidopsis thaliana) causes elevated amounts of 18-carbon-length cutin monomers and a dramatic shift in the cuticular wax profile (especially on leaves) toward the very-long-chain free fatty acids tetracosanoic acid (C24) and hexacosanoic acid (C26). Relative to the wild type, cer9 mutants exhibit elevated cuticle membrane thickness over epidermal cells and cuticular ledges with increased occlusion of the stomatal pore. The cuticular phenotypes of cer9 are associated with delayed onset of wilting in plants experiencing water deficit, lower transpiration rates, and improved water use efficiency measured as carbon isotope discrimination. The CER9 protein thus encodes a novel determinant of plant drought tolerance-associated traits, one whose deficiency elevates cutin synthesis, redistributes wax composition, and suppresses transpiration. Map-based cloning identified CER9, and sequence analysis predicted that it encodes an E3 ubiquitin ligase homologous to yeast Doa10 (previously shown to target endoplasmic reticulum proteins for proteasomal degradation). To further elucidate CER9 function, the impact of CER9 deficiency on interactions with other genes was examined using double mutant and transcriptome analyses. For both wax and cutin, cer9 showed mostly additive effects with cer6, long-chain acyl-CoA synthetase1 (lacs1), and lacs2 and revealed its role in early steps of both wax and cutin synthetic pathways. Transcriptome analysis revealed that the cer9 mutation affected diverse cellular processes, with primary impact on genes associated with diverse stress responses. The discovery of CER9 lays new groundwork for developing novel cuticle-based strategies for improving the drought tolerance and water use efficiency of crop plants. © 2012 American Society of Plant Biologists. All Rights Reserved.

  20. Cuticle-degrading proteases and toxins as virulence markers of Beauveria bassiana (Balsamo) Vuillemin.

    Science.gov (United States)

    Cito, Annarita; Barzanti, Gian Paolo; Strangi, Agostino; Francardi, Valeria; Zanfini, Assunta; Dreassi, Elena

    2016-09-01

    Beauveria bassiana is one of the most known entomopathogenic fungal species and its entomopathogenic mechanism involves several bioactive metabolites, mainly cuticle-degrading enzymes and toxic molecules, which are predicted to play a key role as virulence factors. In this study six Beauveria bassiana strains (B 13/I03, B 13/I11, B 13/I49, B 13/I57, B 13/I63, and B 13/I64) were assayed against Tenebrio molitor larvae. Enzymatic activity of total proteases and specifically Pr 1 and Pr 2, as well as the production of toxic compounds were investigated in each fungal strain. Toxins were detected both in vitro-in medium filtrates and mycelia-and in vivo-in Tenebrio molitor larvae infected by the fungal strains tested. B 13/I11 and B 13/I63 strains showed the most significant entomopathogenic activity against Tenebrio molitor larvae (cumulative mortality rate 100 and 97%, respectively; average survival time 5.85 and 6.74 days, respectively). A widely variable and fungal strain-dependent enzymatic activity of total proteases, Pr 1 and Pr 2 was found. Beauvericin, beauvericin A and bassianolide resulted the most prevalent toxins detected in the substrates analyzed. It has been found that an increase of beauvericin content in vivo resulted significantly correlated to a decrease of Tenebrio molitor larvae average survival time in entomopathogenic bioassay (inverse correlation). The involvement of beauvericin in B. bassiana entomopathogenic process is confirmed; in vitro analysis of cuticle degrading proteases activity and toxins production in relation to the methods adopted resulted insufficient for a rapid screening to determine the virulence of B. bassiana strains against Tenebrio molitor larvae. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. A Novel, Extremely Elongated, and Endocellular Bacterial Symbiont Supports Cuticle Formation of a Grain Pest Beetle

    Directory of Open Access Journals (Sweden)

    Bin Hirota

    2017-09-01

    Full Text Available The saw-toothed grain beetle, Oryzaephilus surinamensis (Silvanidae, is a cosmopolitan stored-product pest. Early studies on O. surinamensis in the 1930s described the presence of peculiar bacteriomes harboring endosymbiotic bacteria in the abdomen. Since then, however, the microbiological nature of the symbiont has been elusive. Here we investigated the endosymbiotic system of O. surinamensis in detail. In the abdomen of adults, pupae, and larvae, four oval bacteriomes were consistently identified, whose cytoplasm was full of extremely elongated tubular bacterial cells several micrometers wide and several hundred micrometers long. Molecular phylogenetic analysis identified the symbiont as a member of the Bacteroidetes, in which the symbiont was the most closely related to the endosymbiont of a grain pest beetle, Rhyzopertha dominica (Bostrichidae. The symbiont was detected in developing embryos, corroborating vertical symbiont transmission through host generations. The symbiont gene showed AT-biased nucleotide composition and accelerated molecular evolution, plausibly reflecting degenerative evolution of the symbiont genome. When the symbiont infection was experimentally removed, the aposymbiotic insects grew and reproduced normally, but exhibited a slightly but significantly more reddish cuticle and lighter body mass. These results indicate that the symbiont of O. surinamensis is not essential for the host’s growth and reproduction but contributes to the host’s cuticle formation. Symbiont genome sequencing and detailed comparison of fitness parameters between symbiotic and aposymbiotic insects under various environmental conditions will provide further insights into the symbiont’s biological roles for the stored-product pest.

  2. 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.

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

    Directory of Open Access Journals (Sweden)

    Naresh Arora

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

  4. The demosponge Pseudoceratina purpurea as a new source of fibrous chitin.

    Science.gov (United States)

    Żółtowska-Aksamitowska, Sonia; Tsurkan, Mikhail V; Lim, Swee-Cheng; Meissner, Heike; Tabachnick, Konstantin; Shaala, Lamiaa A; Youssef, Diaa T A; Ivanenko, Viatcheslav N; Petrenko, Iaroslav; Wysokowski, Marcin; Bechmann, Nicole; Joseph, Yvonne; Jesionowski, Teofil; Ehrlich, Hermann

    2018-06-01

    Among marine demosponges (Porifera: Demospongiae), only representatives of the order Verongiida have been recognized to synthetize both biologically active substances as well as scaffolds-like fibrous skeletons made of structural aminopolysaccharide chitin. The unique 3D architecture of such scaffolds open perspectives for their applications in waste treatment, biomimetics and tissue engineering. Here, we focus special attention to the demosponge Pseudoceratina purpurea collected in the coastal waters of Singapore. For the first time the detailed description of the isolation of chitin from the skeleton of this sponge and its identification using diverse bioanalytical tools were carried out. Calcofluor white staining, FTIR analysis, electrospray ionization mass spectrometry (ESI-MS), SEM, and fluorescence microscopy as well as a chitinase digestion assay were applied in order to confirm with strong evidence the finding of alpha-chitin in the skeleton of P. purpurea. We suggest that the discovery of chitin within representatives of Pseudoceratinidae family is a perspective step in evaluation of these verongiid sponges as novel renewable sources for both chitin and biologically active metabolites, which are of prospective use for marine oriented biomedicine and pharmacology, respectively. Copyright © 2018 Elsevier B.V. All rights reserved.

  5. Extraction and Characterization of Chitin and Chitosan from Blue Crab and Synthesis of Chitosan Cryogel Scaffolds

    Directory of Open Access Journals (Sweden)

    Nimet Bölgen

    2016-08-01

    Full Text Available Polymeric scaffolds produced by cryogelation technique have attracted increasing attention for tissue engineering applications. Cryogelation is a technique which enables to produce interconnected porous matrices from the frozen reaction mixtures of polymers or monomeric precursors. Chitosan is a biocompatible, biodegradable, nontoxic, antibacterial, antioxidant and antifungal natural polymer that is obtained by deacetylation of chitin, which is mostly found in the exoskeleton of many crustacean. In this study, chitin was isolated from the exoskeleton of blue crap (Callinectes sapidus using a chemical method. Callinectes sapidus samples were collected from a market, as a waste material after it has been consumed as food. Demineralization, deproteinization and decolorization steps were applied to the samples to obtain chitin. Chitosan was prepared from isolated chitin by deacetylation at high temperatures. The chemical compositon of crab shell, extracted chitin and chitosan were characterized with FTIR analyses. And also to determine the physicochemical and functional properties of the produced chitosan; solubility, water binding and fat binding analysis were performed. Chitosan cryogel scaffolds were prepared by crosslinking reaction at cryogenic conditions at constant amount of chitosan (1%, w/v with different ratios of glutaraldehyde (1, 3, and 6%, v/v as crosslinker. The chemical structure of the scaffolds were examined by FTIR. Also, the water uptake capacity of scaffolds have been determined. Collectively, the results suggested that the characterized chitosan cryogels can be potential scaffolds to be used in tissue engineering applications.

  6. Chitin's Functionality as a Novel Disintegrant: Benchmarking Against Commonly Used Disintegrants in Different Physicochemical Environments.

    Science.gov (United States)

    Chaheen, Mohammad; Soulairol, Ian; Bataille, Bernard; Yassine, Ahmad; Belamie, Emmanuel; Sharkawi, Tahmer

    2017-07-01

    Disintegrants are used as excipients to ensure rapid disintegration of pharmaceutical tablets and further ensure proper dissolution of the active pharmaceutical ingredient. This study investigates disintegration mechanisms of chitin and common disintegrants. Swelling assessment (swelling force and swelling ratio) in different media, and compaction behavior (pure or mixed with other excipients) tabletability, deformation (Heckel modeling), and compact disintegration times were investigated on the tested disintegrants (alginic acid calcium salt, crospovidone, sodium starch glycolate, croscarmellose sodium, and chitin). Results show that the physicochemical properties of the disintegration medium such as pH and ionic strength, as well as other formulation ingredients, affect the disintegrant functionalities. Heckel analysis using the mean yield pressure "Py" shows that alginic acid calcium salt is the most brittle among the studied disintegrants, while crospovidone has the most plastic deformation mechanism, followed by chitin. Chitin showed good tabletability and disintegration properties that were not influenced by the physicochemical formulation environment. Chitin is largely available and easily modifiable and thus a promising material that could be used as a multifunctional excipient in tablet formulation. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

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

    DEFF Research Database (Denmark)

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

    2011-01-01

    Salmonella contain genes annotated as chitinases; however, their chitinolytic activities have never been verified. We now demonstrate such an activity for a chitinase assigned to glycoside hydrolase family 18 encoded by the SL0018 (chiA) gene in Salmonella enterica Typhimurium SL1344. A C......-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-ß-D-chitobioside, 4-nitrophenyl ß...

  8. 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

    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

  9. Compression-cuticle relationship of seed ferns: Insights from liquid-solid states FTIR (Late Palaeozoic-Early Mesozoic, Canada-Spain-Argentina)

    Science.gov (United States)

    Zodrow, E.L.; D'Angelo, J. A.; Mastalerz, Maria; Keefe, D.

    2009-01-01

    Cuticles have been macerated from suitably preserved compressed fossil foliage by Schulze's process for the past 150 years, whereas the physical-biochemical relationship between the "coalified layer" with preserved cuticle as a unit has hardly been investigated, although they provide complementary information. This relationship is conceptualized by an analogue model of the anatomy of an extant leaf: "vitrinite (mesophyll) + cuticle (biomacropolymer) = compression". Alkaline solutions from Schulze's process as a proxy for the vitrinite, are studied by means of liquid-solid states Fourier transform infrared spectroscopy (FTIR). In addition, cuticle-free coalified layers and fossilized cuticles of seed ferns mainly from Canada, Spain and Argentina of Late Pennsylvanian-Late Triassic age are included in the study sample. Infrared data of cuticle and alkaline solutions differ which is primarily contingent on the mesophyll +biomacropolymer characteristics. The compression records two pathways of organic matter transformation. One is the vitrinized component that reflects the diagenetic-post-diagenetic coalification history parallel with the evolution of the associated coal seam. The other is the cuticle that reflects the sum-total of evolutionary pathway of the biomacropolymer, its monomeric, or polymeric fragmentation, though factors promoting preservation include entombing clay minerals and lower pH conditions. Caution is advised when interpreting liquid-state-based FTIR data, as some IR signals may have resulted from the interaction of Schulze's process with the cuticular biochemistry. A biochemical-study course for taphonomy is suggested, as fossilized cuticles, cuticle-free coalified layers, and compressions are responses to shared physicogeochemical factors. ?? 2009 Elsevier B.V. All rights reserved.

  10. Compression-cuticle relationship of seed ferns: Insights from liquid-solid states FTIR (Late Palaeozoic-Early Mesozoic, Canada-Spain-Argentina)

    Energy Technology Data Exchange (ETDEWEB)

    Zodrow, Erwin L. [Palaeobotanical Laboratory, Cape Breton University, Sydney, Nova Scotia (Canada); D' Angelo, Jose A. [Instituto Argentino de Nivologia, Glaciologia y Ciencias Ambientales (IANIGLA), CCT-CONICET-Mendoza, Avda. Ruiz Leal s/n Parque Gral. San Martin (5500) Mendoza (Argentina); Area de Quimica, Instituto de Ciencias Basicas, Universidad Nacional de Cuyo, Centro Universitario - M5502JMA - Mendoza (Argentina); Mastalerz, Maria [Indiana Geological Survey, Indiana University, 611 North Walnut Grove, Bloomington, IN 47405-2208 (United States); Keefe, Dale [Molecular Spectroscopy Research Laboratory, Department of Chemistry, Cape Breton University, Sydney, Nova Scotia (Canada)

    2009-08-01

    Cuticles have been macerated from suitably preserved compressed fossil foliage by Schulze's process for the past 150 years, whereas the physical-biochemical relationship between the ''coalified layer'' with preserved cuticle as a unit has hardly been investigated, although they provide complementary information. This relationship is conceptualized by an analogue model of the anatomy of an extant leaf: ''vitrinite (mesophyll) + cuticle (biomacropolymer) = compression''. Alkaline solutions from Schulze's process as a proxy for the vitrinite, are studied by means of liquid-solid states Fourier transform infrared spectroscopy (FTIR). In addition, cuticle-free coalified layers and fossilized cuticles of seed ferns mainly from Canada, Spain and Argentina of Late Pennsylvanian-Late Triassic age are included in the study sample. Infrared data of cuticle and alkaline solutions differ which is primarily contingent on the mesophyll +biomacropolymer characteristics. The compression records two pathways of organic matter transformation. One is the vitrinized component that reflects the diagenetic-post-diagenetic coalification history parallel with the evolution of the associated coal seam. The other is the cuticle that reflects the sum-total of evolutionary pathway of the biomacropolymer, its monomeric, or polymeric fragmentation, though factors promoting preservation include entombing clay minerals and lower pH conditions. Caution is advised when interpreting liquid-state-based FTIR data, as some IR signals may have resulted from the interaction of Schulze's process with the cuticular biochemistry. A biochemical-study course for taphonomy is suggested, as fossilized cuticles, cuticle-free coalified layers, and compressions are responses to shared physicogeochemical factors. (author)

  11. 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. Copyright © 2011 Elsevier B.V. All rights reserved.

  12. 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.

  13. Characterization of chitin extracted from fish scales of marine fish species purchased from local markets in North Sulawesi, Indonesia

    Science.gov (United States)

    Rumengan, I. F. M.; Suptijah, P.; Wullur, S.; Talumepa, A.

    2017-10-01

    Chitin is a biodegradable biopolymer with a variety of commercial applications, including in the food food-supplement industries as a marine-derived nutraceutical. The purpose of this study was to characterize the molecular structure of chitin extracted from fish scales of important marine fish purchased from local markets in North Sulawesi. Chitin compound material was obtained from a specific fish scale, and then sequentially carrying out a boiling treatment to separate it from a complex with collagen. From the scales of two fish species, parrotfish (Chlorurus sordidus) and red snapper (Lutjanus argentimaculatus), the rendemen of chitin obtained were 45 % and 33%, respectively. Structural characteristics of the chitin were discussed by FTIR (Fourier Transform Infrared) analysis data. FTIR analysis was done using infrared spectroscopy, which is the resulting spectrum represents the molecular absorption and transmission, creating a molecular fingerprint of the sample. The molecular structure of chitin, C18H26N2O10, where the hydroxyl group on the second carbon replaced by acetyl amide, was shown by the infrared spectra. In the infrared spectra, chitin from parrot fish scales indicated the amide band at 1627.13 cm-1, and chitin from red snapper fish scales the amide band at 1648.09 cm-1 which are a typical one for marine chitin. The hydroxyl and amino bands at the ranged spectra up to 3500 cm-1. The yields of chitin isolated from fish scale were relatively huge. Some treatments are necessary to confirm the molecular conformation and deacetylation behavior. All products from the extraction of fish scales could be more accessible for structural modifications to develop biocompatible materials for pharmaceutical purposes.

  14. Towards the Shell Biorefinery: Sustainable Synthesis of the Anticancer Alkaloid Proximicin A from Chitin.

    Science.gov (United States)

    Sadiq, Alejandro D; Chen, Xi; Yan, Ning; Sperry, Jonathan

    2018-02-09

    A shell biorefinery would involve fractionation of crustacean shells and incorporation of the components into value-added products, particularly those that contain nitrogen. In a proof-of-concept study that validates this concept, the anticancer alkaloid proximicin A has been synthesized from the chitin-derived platform chemical 3-acetamido-5-acetylfuran (3A5AF). This study accentuates the leading role chitin is likely to play in the sustainable production of nitrogen-containing fine chemicals that are not directly attainable from lignocellulose. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Hierarchical Chitin Fibers with Aligned Nanofibrillar Architectures: A Nonwoven-Mat Separator for Lithium Metal Batteries.

    Science.gov (United States)

    Kim, Joong-Kwon; Kim, Do Hyeong; Joo, Se Hun; Choi, Byeongwook; Cha, Aming; Kim, Kwang Min; Kwon, Tae-Hyuk; Kwak, Sang Kyu; Kang, Seok Ju; Jin, Jungho

    2017-06-27

    Here, we introduce regenerated fibers of chitin (Chiber), the second most abundant biopolymer after cellulose, and propose its utility as a nonwoven fiber separator for lithium metal batteries (LMBs) that exhibits an excellent electrolyte-uptaking capability and Li-dendrite-mitigating performance. Chiber is produced by a centrifugal jet-spinning technique, which allows a simple and fast production of Chibers consisting of hierarchically aligned self-assembled chitin nanofibers. Following the scrutinization on the Chiber-Li-ion interaction via computational methods, we demonstrate the potential of Chiber as a nonwoven mat-type separator by monitoring it in Li-O 2 and Na-O 2 cells.

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

    Science.gov (United States)

    Yang, Yue-ping; Xu, Xin-hua; Chen, Hai-feng

    2004-04-01

    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% COD(cr), raise pH from 0.7 to 5.5. The COD(cr) 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.

  17. Eco-Friendly Extraction of Biopolymer Chitin and Carotenoids from Shrimp Waste

    Science.gov (United States)

    Prameela, K.; Venkatesh, K.; Divya vani, K.; Sudesh Kumar, E.; Mohan, CH Murali

    2017-08-01

    Astaxanthin a nutraceutical and chitin a natural biopolymer present in shrimp waste. In current chemical extraction methods HCl and NaOH are used for extraction and these chemicals are introduced into aquatic ecosystems are spoiling aquatic flora and fauna, pollute the environment and destroy astaxanthin. Lactobacillus species were isolated from gut of Solenocera melantho and characterized phenotypically and genotypically. Initial screening experiments have shown to be an effective and identified as Lactobacillus plantaram based on morphological, biochemical characteristics and molecular analysis. Efficiency of fermentation has shown with good yield of astaxanthin and recovery of chitin. Hence this alternative microbial process is having advantage than existing hazardous, non-economical chemical process.

  18. Location on chitin in the cyst wall of Entamoeba invadens with colloidal gold tracers.

    Science.gov (United States)

    Arroyo-Begovich, A; Cárabez-Trejo, A

    1982-04-01

    Chitin was located in the cyst wall of Entamoeba invadens with colloidal gold-linked wheat germ agglutinin. Cysts stained differentially from trophozoites when encysting cultures were treated with the gold tracer; cysts acquired a wine-red coloration while, in general trophozoites remained unstained. Observation of cells with the electron microscope revealed that the tracer particles were bound specifically to the walls of the surface of the cyst when cells were exposed in suspension, and to the cyst wall cross-section, when cells were exposed to the tracer in thin section, indicating that chitin fibers were distributed on the surface as well as throughout the matrix of the cyst wall.

  19. Application of Chitin/Chitosan and Their Derivatives in the Papermaking Industry

    Directory of Open Access Journals (Sweden)

    Zhaoping Song

    2018-04-01

    Full Text Available Chitin/chitosan and their derivatives have become of great interest as functional materials in many fields within the papermaking industry. They have been employed in papermaking wet-end, paper surface coating, papermaking wastewater treatment, and other sections of the papermaking industry due to their structure and chemical properties. The purpose of this paper is to briefly discuss the application of chitin/chitosan and their derivatives in the papermaking industry. The development of their application in the papermaking area will be reviewed and summarized.

  20. Direct surface analysis coupled to high-resolution mass spectrometry reveals heterogeneous composition of the cuticle of Hibiscus trionum petals.

    Science.gov (United States)

    Giorio, Chiara; Moyroud, Edwige; Glover, Beverley J; Skelton, Paul C; Kalberer, Markus

    2015-10-06

    Plant cuticle, which is the outermost layer covering the aerial parts of all plants including petals and leaves, can present a wide range of patterns that, combined with cell shape, can generate unique physical, mechanical, or optical properties. For example, arrays of regularly spaced nanoridges have been found on the dark (anthocyanin-rich) portion at the base of the petals of Hibiscus trionum. Those ridges act as a diffraction grating, producing an iridescent effect. Because the surface of the distal white region of the petals is smooth and noniridescent, a selective chemical characterization of the surface of the petals on different portions (i.e., ridged vs smooth) is needed to understand whether distinct cuticular patterns correlate with distinct chemical compositions of the cuticle. In the present study, a rapid screening method has been developed for the direct surface analysis of Hibiscus trionum petals using liquid extraction surface analysis (LESA) coupled with high-resolution mass spectrometry. The optimized method was used to characterize a wide range of plant metabolites and cuticle monomers on the upper (adaxial) surface of the petals on both the white/smooth and anthocyanic/ridged regions, and on the lower (abaxial) surface, which is entirely smooth. The main components detected on the surface of the petals are low-molecular-weight organic acids, sugars, and flavonoids. The ridged portion on the upper surface of the petal is enriched in long-chain fatty acids, which are constituents of the wax fraction of the cuticle. These compounds were not detected on the white/smooth region of the upper petal surface or on the smooth lower surface.

  1. 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.

  2. CFLAP1 and CFLAP2 Are Two bHLH Transcription Factors Participating in Synergistic Regulation of AtCFL1-Mediated Cuticle Development in Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Shibai Li

    2016-01-01

    Full Text Available The cuticle is a hydrophobic lipid layer covering the epidermal cells of terrestrial plants. Although many genes involved in Arabidopsis cuticle development have been identified, the transcriptional regulation of these genes is largely unknown. Previously, we demonstrated that AtCFL1 negatively regulates cuticle development by interacting with the HD-ZIP IV transcription factor HDG1. Here, we report that two bHLH transcription factors, AtCFL1 associated protein 1 (CFLAP1 and CFLAP2, are also involved in AtCFL1-mediated regulation of cuticle development. CFLAP1 and CFLAP2 interact with AtCFL1 both in vitro and in vivo. Overexpression of either CFLAP1 or CFLAP2 led to expressional changes of genes involved in fatty acids, cutin and wax biosynthesis pathways and caused multiple cuticle defective phenotypes such as organ fusion, breakage of the cuticle layer and decreased epicuticular wax crystal loading. Functional inactivation of CFLAP1 and CFLAP2 by chimeric repression technology caused opposite phenotypes to the CFLAP1 overexpressor plants. Interestingly, we find that, similar to the transcription factor HDG1, the function of CFLAP1 in cuticle development is dependent on the presence of AtCFL1. Furthermore, both HDG1 and CFLAP1/2 interact with the same C-terminal C4 zinc finger domain of AtCFL1, a domain that is essential for AtCFL1 function. These results suggest that AtCFL1 may serve as a master regulator in the transcriptional regulation of cuticle development, and that CFLAP1 and CFLAP2 are involved in the AtCFL1-mediated regulation pathway, probably through competing with HDG1 to bind to AtCFL1.

  3. Chirality-induced polarization effects in the cuticle of scarab beetles: 100 years after Michelson

    Science.gov (United States)

    Arwin, Hans; Magnusson, Roger; Landin, Jan; Järrendahl, Kenneth

    2012-04-01

    One hundred years ago Michelson discovered circular polarization in reflection from beetles. Today a novel Mueller-matrix ellipsometry setup allows unprecedented detailed characterization of the beetles' polarization properties. A formalism based on elliptical polarization for description of reflection from scarab beetles is here proposed and examples are given on four beetles of different character: Coptomia laevis - a simple dielectric mirror; Cetonia aurata - a left-hand narrow-band elliptical polarizer; Anoplognathus aureus - a broad-band elliptical polarizer; and Chrysina argenteola - a left-hand polarizer for visible light at small angles, whereas for larger angles, red reflected light is right-handed polarized. We confirm the conclusion of previous studies which showed that a detailed quantification of ellipticity and degree of polarization of cuticle reflection can be performed instead of only determining whether reflections are circularly polarized or not. We additionally investigate reflection as a function of incidence angle. This provides much richer information for understanding the behaviour of beetles and for structural analysis.

  4. 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.

    2012-01-01

    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. PMID:22964252

  5. Seasonality influences cuticle melanization and immune defense in a cricket: support for a temperature-dependent immune investment hypothesis in insects

    Energy Technology Data Exchange (ETDEWEB)

    Fedorka, K. M. [Univ. of Central Florida, Orlando, FL (United States); Copeland, E. K. [Univ. of Central Florida, Orlando, FL (United States); Winterhalter, W. E. [Univ. of Central Florida, Orlando, FL (United States)

    2013-07-18

    To improve thermoregulation in colder environments, insects are expected to darken their cuticles with melanin via the phenoloxidase cascade, a phenomenon predicted by the thermal melanin hypothesis. However, the phenoloxidase cascade also plays a significant role in insect immunity, leading to the additional hypothesis that the thermal environment indirectly shapes immune function via direct selection on cuticle color. Support for the latter hypothesis comes from the cricket Allonemobius socius, where cuticle darkness and immune-related phenoloxidase activity increase with latitude. However, thermal environments vary seasonally as well as geographically, suggesting that seasonal plasticity in immunity may also exist. Although seasonal fluctuations in vertebrate immune function are common (because of flux in breeding or resource abundance), seasonality in invertebrate immunity has not been widely explored. We addressed this possibility by rearing crickets in simulated summer and fall environments and assayed their cuticle color and immune function. Prior to estimating immunity, crickets were placed in a common environment to minimize metabolic rate differences. Individuals reared under fall-like conditions exhibited darker cuticles, greater phenoloxidase activity and greater resistance to the bacteria Serratia marcescens. These data support the hypothesis that changes in the thermal environment modify cuticle color, which indirectly shapes immune investment through pleiotropy. This hypothesis may represent a widespread mechanism governing immunity in numerous systems, considering that most insects operate in seasonally and geographically variable thermal environments.

  6. Isolation of proteolytic bacteria from mealworm (Tenebrio molitor) exoskeletons to produce chitinous material.

    Science.gov (United States)

    da Silva, Fernanda Kerche Paes; Brück, Dieter W; Brück, Wolfram M

    2017-09-15

    The use of insects as a source of protein is becoming an important factor for feeding an increasing population. After protein extraction for food use, the insect exoskeleton may offer the possibility for the production of added value products. Here, the aim was to isolate bacteria from the surface of farmed mealworms (Tenebrio molitor Linnaeus, 1758) for the production of chitinous material from insect exoskeletons using microbial fermentation. Isolates were screened for proteases and acid production that may aid deproteination and demineralisation of insects through fermentation to produce chitin. Selected isolates were used single-step (isolated bacteria only) or two-step fermentations with Lactobacillus plantarum (DSM 20174). Two-step fermentations with isolates from mealworm exoskeletons resulted in a demineralisation of 97.9 and 98.5% from deproteinated mealworm fractions. Attenuated total reflectance-Fourier- transform infrared spectroscopy analysis showed that crude chitin was produced. However, further optimisation is needed before the process can be upscaled. This is, to our knowledge, the first report using microbial fermentation for the extraction of chitin from insects. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  7. Current Status and New Perspectives on Chitin and Chitosan as Functional Biopolymers.

    Science.gov (United States)

    Philibert, Tuyishime; Lee, Byong H; Fabien, Nsanzabera

    2017-04-01

    The natural biopolymer chitin and its deacetylated product chitosan are found abundantly in nature as structural building blocks and are used in all sectors of human activities like materials science, nutrition, health care, and energy. Far from being fully recognized, these polymers are able to open opportunities for completely novel applications due to their exceptional properties which an economic value is intrinsically entrapped. On a commercial scale, chitosan is mainly obtained from crustacean shells rather than from the fungal and insect sources. Significant efforts have been devoted to commercialize chitosan extracted from fungal and insect sources to completely replace crustacean-derived chitosan. However, the traditional chitin extraction processes are laden with many disadvantages. The present review discusses the potential bioextraction of chitosan from fungal, insect, and crustacean as well as its superior physico-chemical properties. The different aspects of fungal, insects, and crustacean chitosan extraction methods and various parameters having an effect on the yield of chitin and chitosan are discussed in detail. In addition, this review also deals with essential attributes of chitosan for high value-added applications in different fields and highlighted new perspectives on the production of chitin and deacetylated chitosan from different sources with the concomitant reduction of the environmental impact.

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

    Czech Academy of Sciences Publication Activity Database

    Abdel-Mohsen, A. M.; Jancar, J.; Massoud, D.; Fohlerová, Z.; Elhadidy, Hassan; Spotz, Z.; Hebeish, A.

    2016-01-01

    Roč. 510, č. 1 (2016), s. 86-99 ISSN 0378-5173 R&D Projects: GA MŠk(CZ) LQ1601 Institutional support: RVO:68081723 Keywords : Chitin/chitosan-glucan complex * Nonwoven mat * Surgical wound healing Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.649, year: 2016

  9. Chitosan/chitin nanowhiskers composites: effect of plasticisers on the mechanical behaviour

    Czech Academy of Sciences Publication Activity Database

    Kelnar, Ivan; Kovářová, Jana; Tishchenko, Galina; Kaprálková, Ludmila; Pavlova, Ewa; Carezzi, F.; Morganti, P.

    2015-01-01

    Roč. 22, č. 2 (2015), 5_1-5_6 ISSN 1022-9760 R&D Projects: GA ČR(CZ) GA13-15255S EU Projects: European Commission(XE) 315233 - N-CHITOPACK Institutional support: RVO:61389013 Keywords : chitosan * chitin nanowhiskers * composite Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.969, year: 2015

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

    CSIR Research Space (South Africa)

    Naseria, N

    2014-08-01

    Full Text Available The aim of this study was to develop electrospun chitosan/polyethylene oxide-based randomly oriented fiber mats reinforced with chitin nanocrystals (ChNC) for wound dressing. Microscopy studies showedporous mats of smooth and beadless fibers...

  11. 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

  12. 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 (p<0.001) increase in the absorption capacity. Moisture vapour transmission rate of the membranes was 4285.77±455.61 g/m2/24 h at 24 h. Gamma irradiation at 25 kGy was found suitable for sterilization of the dressings. Infrared (IR) spectral scanning has shown that papain was stable on gamma irradiation at 25-35 kGy. The irradiated chitin-papain membranes were impermeable to different bacterial strains and also exhibited strong bactericidal action against both Gram-positive and Gram-negative bacteria. The fluid handling characteristics and the antimicrobial properties of chitin-papain membranes sterilized by gamma radiation were found suitable for use as wound dressing with debriding activity.

  13. Morphological study of chitin from Xiphopenaeus kroyeri exoskeletons by using atomic force microscopy (AFM) and CPMAS 13 C NMR

    International Nuclear Information System (INIS)

    Silva, K.M.; Tavares, M.I.; Andrade, C.T.; Simao, R.A.

    1999-01-01

    A sample of α chitin was isolated from exoskeletons of Xiphopenaeus kroyeri. This sample ws dissolved in phosphoric acid and recovered as a fibrous precipitate. Atomic force microscopy was used in noncontact mode to obtain images of the native chitin sample. Different morphological features were observed, including rigid rod crystals 200-300 nm wide. Solid state 13 C NMR techniques were used to investigate chitin samples, and revealed molecular order in both samples. The differences observed in the proton spin-lattice relaxation times in the rotating frame, T H1 p were attributed to the formation of hydrogen bonds in preferential sites in the samples. (author)

  14. Effect of egg washing and correlation between cuticle and egg penetration by various Salmonella strains.

    Science.gov (United States)

    Gole, Vaibhav C; Roberts, Juliet R; Sexton, Margaret; May, Damian; Kiermeier, Andreas; Chousalkar, Kapil K

    2014-07-16

    In Australia, Europe and the United States, eggs and egg products are frequently associated with Salmonella food poisoning outbreaks. Many of the egg-associated Salmonella outbreaks have been due to the products such as mayonnaise, ice-cream and cold desserts which are eaten without cooking following the addition of raw egg. The ability of four Salmonella isolates (one each of S. Singapore, S. Adelaide, S. Worthington and S. Livingstone) to penetrate washed and unwashed eggs using whole egg and agar egg penetration methods was investigated in the current study. The results of the agar penetration experiment indicated that all the isolates used in the present study have the capacity to penetrate the eggshell. Eggshell penetration by the S. Worthington isolate was higher but not significant (p=0.06) in washed eggs compared to unwashed eggs. However, for all other isolates (S. Singapore, S. Adelaide and S. Livingstone), there was no significant difference in penetration of washed and unwashed eggs. Statistical analysis indicated that cuticle score was a significant linear predictor of Salmonella eggshell penetration. Whole egg penetration results showed that all of the Salmonella isolates used in the present study were capable of surviving on the eggshell surface after 21days of incubation (at 20°C) following a high dose of inoculation (10(5)CFU/mL). The combined data of all isolates demonstrated that, the survival rate of Salmonella on eggshells (inoculated with 10(5)CFU/mL) was significantly higher (p=0.002) at 20°C as compared to 37°C. S. Singapore, S. Worthington, and S. Livingstone were not detected in egg internal contents whereas S. Adelaide was detected in one egg's internal contents. Crown Copyright © 2014. Published by Elsevier B.V. All rights reserved.

  15. New functions of arthropod bursicon: inducing deposition and thickening of new cuticle and hemocyte granulation in the blue crab, Callinectes sapidus.

    Directory of Open Access Journals (Sweden)

    J Sook Chung

    Full Text Available Arthropod growth requires molt-associated changes in softness and stiffness of the cuticle that protects from desiccation, infection and injury. Cuticle hardening in insects depends on the blood-borne hormone, bursicon (Burs, although it has never been determined in hemolymph. Whilst also having Burs, decapod crustaceans reiterate molting many more times during their longer life span and are encased in a calcified exoskeleton, which after molting undergoes similar initial cuticle hardening processes as in insects. We investigated the role of homologous crustacean Burs in cuticular changes and growth in the blue crab, Callinectes sapidus. We found dramatic increases in size and number of Burs cells during development in paired thoracic ganglion complex (TGC neurons with pericardial organs (POs as neurohemal release sites. A skewed expression of Burs β/Burs α mRNA in TGC corresponds to protein contents of identified Burs β homodimer and Burs heterodimer in POs. In hemolymph, Burs is consistently present at ∼21 pM throughout the molt cycle, showing a peak of ∼89 pM at ecdysis. Since initial cuticle hardness determines the degree of molt-associated somatic increment (MSI, we applied recombinant Burs in vitro to cuticle explants of late premolt or early ecdysis. Burs stimulates cuticle thickening and granulation of hemocytes. These findings demonstrate novel cuticle-associated functions of Burs during molting, while the unambiguous and constant presence of Burs in cells and hemolymph throughout the molt cycle and life stages may implicate further functions of its homo- and heterodimer hormone isoforms in immunoprotective defense systems of arthropods.

  16. 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...... 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...... 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...

  17. Exploring the interior of cuticles and compressions of fossil plants by FIB-SEM milling and image microscopy.

    Science.gov (United States)

    Sender, L M; Escapa, I; Benedetti, A; Cúneo, R; Diez, J B

    2018-01-01

    We present the first study of cuticles and compressions of fossil leaves by Focused Ion Beam Scanning Electron Microscopy (FIB-SEM). Cavities preserved inside fossil leaf compressions corresponding to substomatal chambers have been observed for the first time and several new features were identified in the cross-section cuts. These results open a new way in the investigation of the three-dimensional structures of both micro- and nanostructural features of fossil plants. Moreover, the application of the FIB-SEM technique to both fossils and extant plant remains represent a new source of taxonomical, palaeoenvironmental and palaeoclimatic information. © 2017 The Authors Journal of Microscopy © 2017 Royal Microscopical Society.

  18. Sequence analysis and heterologous expression of the wool cuticle-degrading enzyme encoding genes in Fusarium oxysporum 26-1.

    Science.gov (United States)

    Chaya, Etsushi; Suzuki, Tohru; Karita, Shuichi; Hanya, Akira; Yoshino-Yasuda, Shoko; Kitamoto, Noriyuki

    2014-06-01

    Two protease-like proteins, KrtA and KrtC, were identified in Fusarium oxysporum 26-1. Genes coding these proteins, krtA and krtC, were isolated and characterized. Recombinant KrtA (rKrtA) and KrtC (rKrtC) were successfully expressed in Aspergillus oryzae and secreted. The combination of rKrtA and rKrtC completely removed the cuticle of wool fibers. Copyright © 2013 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  19. 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

    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......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...... or the model ligand acetylated BSA, at different time intervals anddoses and using a luciferase reporter system detection of NFjB activation will be performed and cytokine expression will be quantified via qRT-PCR. Perspectives: Improved understanding of epithelialimmune and inflammatory modulation in response...

  20. The Antifungal Activity of Functionalized Chitin Nanocrystals in Poly (Lactid Acid Films

    Directory of Open Access Journals (Sweden)

    Asier M. Salaberria

    2017-05-01

    Full Text Available As, in the market, poly (lactic acid (PLA is the most used polymer as an alternative to conventional plastics, and as functionalized chitin nanocrystals (CHNC can provide structural and bioactive properties, their combination sounds promising in the preparation of functional nanocomposite films for sustainable packaging. Chitin nanocrystals were successfully modified via acylation using anhydride acetic and dodecanoyl chloride acid to improve their compatibility with the matrix, PLA. The nanocomposite films were prepared by extrusion/compression approach using different concentrations of both sets of functionalized CHNC. This investigation brings forward that both sets of modified CHNC act as functional agents, i.e., they slightly improved the hydrophobic character of the PLA nanocomposite films, and, very importantly, they also enhanced their antifungal activity. Nonetheless, the nanocomposite films prepared with the CHNC modified with dodecanoyl chloride acid presented the best properties.

  1. Preparation, characterization, drug release and computational modelling studies of antibiotics loaded amorphous chitin nanoparticles.

    Science.gov (United States)

    Gayathri, N K; Aparna, V; Maya, S; Biswas, Raja; Jayakumar, R; Mohan, C Gopi

    2017-12-01

    We present a computational investigation of binding affinity of different types of drugs with chitin nanocarriers. Understanding the chitn polymer-drug interaction is important to design and optimize the chitin based drug delivery systems. The binding affinity of three different types of anti-bacterial drugs Ethionamide (ETA) Methacycline (MET) and Rifampicin (RIF) with amorphous chitin nanoparticles (AC-NPs) were studied by integrating computational and experimental techniques. The binding energies (BE) of hydrophobic ETA, hydrophilic MET and hydrophobic RIF were -7.3kcal/mol, -5.1kcal/mol and -8.1kcal/mol respectively, with respect to AC-NPs, using molecular docking studies. This theoretical result was in good correlation with the experimental studies of AC-drug loading and drug entrapment efficiencies of MET (3.5±0.1 and 25± 2%), ETA (5.6±0.02 and 45±4%) and RIF (8.9±0.20 and 53±5%) drugs respectively. Stability studies of the drug encapsulated nanoparticles showed stable values of size, zeta and polydispersity index at 6°C temperature. The correlation between computational BE and experimental drug entrapment efficiencies of RIF, ETA and MET drugs with four AC-NPs strands were 0.999 respectively, while that of the drug loading efficiencies were 0.854 respectively. Further, the molecular docking results predict the atomic level details derived from the electrostatic, hydrogen bonding and hydrophobic interactions of the drug and nanoparticle for its encapsulation and loading in the chitin-based host-guest nanosystems. The present results thus revealed the drug loading and drug delivery insights and has the potential of reducing the time and cost of processing new antibiotic drug delivery nanosystem optimization, development and discovery. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

    OpenAIRE

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

    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 succe...

  3. 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.

  4. In vitro bioconversion of chitin to pyruvate with thermophilic enzymes.

    Science.gov (United States)

    Honda, Kohsuke; Kimura, Keisuke; Ninh, Pham Huynh; Taniguchi, Hironori; Okano, Kenji; Ohtake, Hisao

    2017-09-01

    Chitin is the second most abundant organic compound on the planet and thus has been regarded as an alternative resource to petroleum feedstocks. One of the key challenges in the biological conversion of biomass-derived polysaccharides, such as cellulose and chitin, is to close the gap between optimum temperatures for enzymatic saccharification and microbial fermentation and to implement them in a single bioreactor. To address this issue, in the present study, we aimed to perform an in vitro, one-pot bioconversion of chitin to pyruvate, which is a precursor of a wide range of useful metabolites. Twelve thermophilic enzymes, including that for NAD + regeneration, were heterologously produced in Escherichia coli and semi-purified by heat treatment of the crude extract of recombinant cells. When the experimentally decided concentrations of enzymes were incubated with 0.5 mg mL -1 colloidal chitin (equivalent to 2.5 mM N-acetylglucosamine unit) and an adequate set of cofactors at 70°C, 0.62 mM pyruvate was produced in 5 h. Despite the use of a cofactor-balanced pathway, determination of the pool sizes of cofactors showed a rapid decrease in ATP concentration, most probably due to the thermally stable ATP-degrading enzyme(s) derived from the host cell. Integration of an additional enzyme set of thermophilic adenylate kinase and polyphosphate kinase led to the deceleration of ATP degradation, and the final product titer was improved to 2.1 mM. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  5. Microbial Degradation of Lobster Shells to Extract Chitin Derivatives for Plant Disease Management

    Directory of Open Access Journals (Sweden)

    Gayathri Ilangumaran

    2017-05-01

    Full Text Available Biodegradation of lobster shells by chitinolytic microorganisms are an environment safe approach to utilize lobster processing wastes for chitin derivation. In this study, we report degradation activities of two microbes, “S223” and “S224” isolated from soil samples that had the highest rate of deproteinization, demineralization and chitinolysis among ten microorganisms screened. Isolates S223 and S224 had 27.3 and 103.8 protease units mg-1 protein and 12.3 and 11.2 μg ml-1 of calcium in their samples, respectively, after 1 week of incubation with raw lobster shells. Further, S223 contained 23.8 μg ml-1 of N-Acetylglucosamine on day 3, while S224 had 27.3 μg ml-1 on day 7 of incubation with chitin. Morphological observations and 16S rDNA sequencing suggested both the isolates were Streptomyces. The culture conditions were optimized for efficient degradation of lobster shells and chitinase (∼30 kDa was purified from crude extract by affinity chromatography. The digested lobster shell extracts induced disease resistance in Arabidopsis by induction of defense related genes (PR1 > 500-fold, PDF1.2 > 40-fold upon Pseudomonas syringae and Botrytis cinerea infection. The study suggests that soil microbes aid in sustainable bioconversion of lobster shells and extraction of chitin derivatives that could be applied in plant protection.

  6. Reinforcement of thermoplastic chitosan hydrogel using chitin whiskers optimized with response surface methodology.

    Science.gov (United States)

    Sun, Guohui; Zhang, Xin; Bao, Zixian; Lang, Xuqian; Zhou, Zhongzheng; Li, Yang; Feng, Chao; Chen, Xiguang

    2018-06-01

    To strengthen the mechanical strength of thermo-sensitive hydroxybutyl chitosan (HBC) hydrogel, chitin whiskers were used as sticker to fabricate reinforced HBC (HBCW) hydrogel by using response surface methodology. Unlike the intrinsic network of HBC hydrogel, HBCW hydrogel showed a laminar shape with firm structure. The preparation condition was optimized by three-factor-three-level Box-Behnken design. The maximum mechanical strength (1011.11 Pa) was achieved at 50 °C, when the concentrations of HBC and chitin whiskers were 5.1 wt% and 2.0 wt%, respectively. The effects of temperature, pH value and NaCl concentration on mechanical strength of HBCW hydrogels were investigated via the oscillatory stress sweeps. The results showed that HBCW hydrogel could reach the maximum stiffness (∼1126 Pa) at 37 °C pH 12.0. Low pH and high salty ions could decrease the stability of hydrogel, while chitin whiskers could increase the stress tolerance and related ruptured strain of HBCW hydrogels. Copyright © 2018. Published by Elsevier Ltd.

  7. In vitro evaluation of paclitaxel loaded amorphous chitin nanoparticles for colon cancer drug delivery.

    Science.gov (United States)

    Smitha, K T; Anitha, A; Furuike, T; Tamura, H; Nair, Shantikumar V; Jayakumar, R

    2013-04-01

    Chitin and its derivatives have been widely used in drug delivery applications due to its biocompatible, biodegradable and non-toxic nature. In this study, we have developed amorphous chitin nanoparticles (150±50 nm) and evaluated its potential as a drug delivery system. Paclitaxel (PTX), a major chemotherapeutic agent was loaded into amorphous chitin nanoparticles (AC NPs) through ionic cross-linking reaction using TPP. The prepared PTX loaded AC NPs had an average diameter of 200±50 nm. Physico-chemical characterization of the prepared nanoparticles was carried out. These nanoparticles were proven to be hemocompatible and in vitro drug release studies showed a sustained release of PTX. Cellular internalization of the NPs was confirmed by fluorescent microscopy as well as by flow cytometry. Anticancer activity studies proved the toxicity of PTX-AC NPs toward colon cancer cells. These preliminary results indicate the potential of PTX-AC NPs in colon cancer drug delivery. Copyright © 2012 Elsevier B.V. All rights reserved.

  8. 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.

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

    International Nuclear Information System (INIS)

    Juárez-de la Rosa, B.A.; May-Crespo, J.; Quintana-Owen, P.; Gónzalez-Gómez, W.S.; Yañez-Limón, J.M.; Alvarado-Gil, J.J.

    2015-01-01

    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

  10. Natural waste materials containing chitin as adsorbents for textile dyestuffs: batch and continuous studies.

    Science.gov (United States)

    Figueiredo, S A; Loureiro, J M; Boaventura, R A

    2005-10-01

    In this work three natural waste materials containing chitin were used as adsorbents for textile dyestuffs, namely the Anodonta (Anodonta cygnea) shell, the Sepia (Sepia officinalis) and the Squid (Loligo vulgaris) pens. The selected dyestuffs were the Cibacron green T3G-E (CI reactive green 12), and the Solophenyl green BLE 155% (CI direct green 26), both from CIBA, commonly used in cellulosic fibres dyeing, the most used fibres in the textile industry. Batch equilibrium studies showed that the materials' adsorption capacities increase after a simple and inexpensive chemical treatment, which increases their porosity and chitin relative content. Kinetic studies suggested the existence of a high internal resistance in both systems. Fixed bed column experiments performed showed an improvement in adsorbents' behaviour after chemical treatment. However, in the column experiments, the biodegradation was the main mechanism of dyestuff removal, allowing the materials' bioregeneration. The adsorption was strongly reduced by the pore clogging effect of the biomass. The deproteinised Squid pen (grain size 0.500-1.41 mm) is the adsorbent with highest adsorption capacity (0.27 and 0.037 g/g, respectively, for the reactive and direct dyestuffs, at 20 degrees C), followed by the demineralised Sepia pen and Anodonta shell, behaving like pure chitin in all experiments, but showing inferior performances than the granular activated carbon tested in the column experiments.

  11. Chitinase and chitin synthase 1: counterbalancing activities in cell separation of Saccharomyces cerevisiae.

    Science.gov (United States)

    Cabib, E; Silverman, S J; Shaw, J A

    1992-01-01

    Previous results [E. Cabib, A. Sburlati, B. Bowers & S. J. Silverman (1989) Journal of Cell Biology 108, 1665-1672] strongly suggested that the lysis observed in daughter cells of Saccharomyces cerevisiae defective in chitin synthase 1 (Chs1) was caused by a chitinase that partially degrades the chitin septum in the process of cell separation. Consequently, it was proposed that in wild-type cells, Chs1 acts as a repair enzyme by replenishing chitin during cytokinesis. The chitinase requirement for lysis has been confirmed in two different ways: (a) demethylallosamidin, a more powerful chitinase inhibitor than the previously used allosamidin, is also a much better protector against lysis and (b) disruption of the chitinase gene in chs1 cells eliminates lysis. Reintroduction of a normal chitinase gene, by transformation of those cells with a suitable plasmid, restores lysis. The percentage of lysed cells in strains lacking Chs1 was not increased by elevating the chitinase level with high-copy-number plasmids carrying the hydrolase gene. Furthermore, the degree of lysis varied in different chs1 strains; lysis was abolished in chs1 mutants containing the scs1 suppressor. These results indicate that, in addition to chitinase, lysis requires other gene products that may become limiting.

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

    Science.gov (United States)

    Younes, Islem; Rinaudo, Marguerite

    2015-01-01

    This review describes the most common methods for recovery of chitin from marine organisms. In depth, both enzymatic and chemical treatments for the step of deproteinization are compared, as well as different conditions for demineralization. The conditions of chitosan preparation are also discussed, since they significantly impact the synthesis of chitosan with varying degree of acetylation (DA) and molecular weight (MW). In addition, the main characterization techniques applied for chitin and chitosan are recalled, pointing out the role of their solubility in relation with the chemical structure (mainly the acetyl group distribution along the backbone). Biological activities are also presented, such as: antibacterial, antifungal, antitumor and antioxidant. Interestingly, the relationship between chemical structure and biological activity is demonstrated for chitosan molecules with different DA and MW and homogeneous distribution of acetyl groups for the first time. In the end, several selected pharmaceutical and biomedical applications are presented, in which chitin and chitosan are recognized as new biomaterials taking advantage of their biocompatibility and biodegradability. PMID:25738328

  13. Chitin/clay microspheres with hierarchical architecture for highly efficient removal of organic dyes.

    Science.gov (United States)

    Xu, Rui; Mao, Jie; Peng, Na; Luo, Xiaogang; Chang, Chunyu

    2018-05-15

    Numerous adsorbents have been reported for efficient removal of dye from water, but the high cost raw materials and complicated fabrication process limit their practical applications. Herein, novel nanocomposite microspheres were fabricated from chitin and clay by a simple thermally induced sol-gel transition. Clay nanosheets were uniformly embedded in a nanofiber weaved chitin microsphere matrix, leading to their hierarchical architecture. Benefiting from this unique structure, microspheres could efficiently remove methylene blue (MB) through a spontaneous physic-sorption process which fit well with pseudo-second-order and Langmuir isotherm models. The maximal values of adsorption capability obtained by calculation and experiment were 152.2 and 156.7 mg g -1 , respectively. Chitin/clay microspheres (CCM2) could remove 99.99% MB from its aqueous solution (10 mg g -1 ) within 20 min. These findings provide insight into a new strategy for fabrication of dye adsorbents with hierarchical structure from low cost raw materials. Copyright © 2018 Elsevier Ltd. All rights reserved.

  14. 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.

  15. Disruption of Bcchs4, Bcchs6 or Bcchs7 chitin synthase genes in Botrytis cinerea and the essential role of class VI chitin synthase (Bcchs6).

    Science.gov (United States)

    Morcx, Serena; Kunz, Caroline; Choquer, Mathias; Assie, Sébastien; Blondet, Eddy; Simond-Côte, Elisabeth; Gajek, Karina; Chapeland-Leclerc, Florence; Expert, Dominique; Soulie, Marie-Christine

    2013-03-01

    Chitin synthases play critical roles in hyphal development and fungal pathogenicity. Previous studies on Botrytis cinerea, a model organism for necrotrophic pathogens, have shown that disruption of Bcchs1 and more particularly Bcchs3a genes have a drastic impact on virulence (Soulié et al., 2003, 2006). In this work, we investigate the role of other CHS including BcCHS4, BcCHS6 and BcCHS7 during the life cycle of B. cinerea. Single deletions of corresponding genes were carried out. Phenotypic analysis indicates that: (i) BcCHS4 enzyme is not essential for development and pathogenicity of the fungus; (ii) BcCHS7 is required for pathogenicity in a host dependant manner. For Bcchs6 gene disruption, we obtained only heterokaryotic strains. Indeed, sexual or asexual purification assays were unsuccessful. We concluded that class VI chitin synthase could be essential for B. cinerea and therefore BcCHS6 represents a valuable antifungal target. Copyright © 2012 Elsevier Inc. All rights reserved.

  16. Chemotaxonomy for naturally macerated tree-fern cuticles (Medullosales and Marattiales), Carboniferous Sydney and Mabou Sub-Basins, Nova Scotia, Canada

    Science.gov (United States)

    Zodrow, E.L.; Mastalerz, Maria

    2001-01-01

    Naturally macerated cuticles (NMC) and one synangium, representing medullosalean and marattialean tree-fern species, from two Carboniferous coalfields in Nova Scotia, Canada, are investigated. The samples were analyzed by infrared spectroscopy (FTIR), and by pyrolysis-gas chromatograph/mass spectrometry (py-Gc/Ms) techniques in search for chemical signatures that would help in developing a chemotaxonomic classification of Carboniferous fern species, assuming genetically dependent make-up of cuticles. FTIR-derived CH2/CH3 ratios, in conjunction with contributions from carboxyl groups, demonstrated a better potential for discriminating between medullosalean genera and species than molecular signatures obtained by py-Gc/Ms. However, the latter provided better data for differentiating medullosalean from marattialean tree ferns as a group. Changes in the chemical make-up of naturally macerated cuticles due to sample preparation are discussed. ?? 2001 Elsevier Science B.V. All rights reserved.

  17. Caenorhabditis elegans BAH-1 is a DUF23 protein expressed in seam cells and required for microbial biofilm binding to the cuticle.

    Directory of Open Access Journals (Sweden)

    Kevin Drace

    2009-08-01

    Full Text Available The cuticle of Caenorhabditis elegans, a complex, multi-layered extracellular matrix, is a major interface between the animal and its environment. Biofilms produced by the bacterial genus Yersinia attach to the cuticle of the worm, providing an assay for surface characteristics. A C. elegans gene required for biofilm attachment, bah-1, encodes a protein containing the domain of unknown function DUF23. The DUF23 domain is found in 61 predicted proteins in C. elegans, which can be divided into three distinct phylogenetic clades. bah-1 is expressed in seam cells, which are among the hypodermal cells that synthesize the cuticle, and is regulated by a TGF-beta signaling pathway.

  18. Chemotaxonomy for naturally macerated tree-fern cuticles (Medullosales and Marattiales), Carboniferous Sydney and Mabou Sub-Basins, Nova Scotia, Canada

    Energy Technology Data Exchange (ETDEWEB)

    Zodrow, Erwin L. [Department of Earth Sciences, University College of Cape Breton, PO Box 5300, Nova Scotia, B1P 6L2 Sydney (Canada); Mastalerz, Maria [Indiana Geological Survey, Indiana University, 611 North Walnut Grove, 47405-2208 Bloomington, IN (United States)

    2001-07-01

    Naturally macerated cuticles (NMC) and one synangium, representing medullosalean and marattialean tree-fern species, from two Carboniferous coalfields in Nova Scotia, Canada, are investigated. The samples were analyzed by infrared spectroscopy (FTIR), and by pyrolysis-gas chromatograph/mass spectrometry (py-Gc/Ms) techniques in search for chemical signatures that would help in developing a chemotaxonomic classification of Carboniferous fern species, assuming genetically dependent make-up of cuticles. FTIR-derived CH{sub 2}/CH{sub 3} ratios, in conjunction with contributions from carboxyl groups, demonstrated a better potential for discriminating between medullosalean genera and species than molecular signatures obtained by py-Gc/Ms. However, the latter provided better data for differentiating medullosalean from marattialean tree ferns as a group. Changes in the chemical make-up of naturally macerated cuticles due to sample preparation are discussed.

  19. Solid-State (13)C NMR Delineates the Architectural Design of Biopolymers in Native and Genetically Altered Tomato Fruit Cuticles.

    Science.gov (United States)

    Chatterjee, Subhasish; Matas, Antonio J; Isaacson, Tal; Kehlet, Cindie; Rose, Jocelyn K C; Stark, Ruth E

    2016-01-11

    Plant cuticles on outer fruit and leaf surfaces are natural macromolecular composites of waxes and polyesters that ensure mechanical integrity and mitigate environmental challenges. They also provide renewable raw materials for cosmetics, packaging, and coatings. To delineate the structural framework and flexibility underlying the versatile functions of cutin biopolymers associated with polysaccharide-rich cell-wall matrices, solid-state NMR spectra and spin relaxation times were measured in a tomato fruit model system, including different developmental stages and surface phenotypes. The hydrophilic-hydrophobic balance of the cutin ensures compatibility with the underlying polysaccharide cell walls; the hydroxy fatty acid structures of outer epidermal cutin also support deposition of hydrophobic waxes and aromatic moieties while promoting the formation of cell-wall cross-links that rigidify and strengthen the cuticle composite during fruit development. Fruit cutin-deficient tomato mutants with compromised microbial resistance exhibit less efficient local and collective biopolymer motions, stiffening their cuticular surfaces and increasing their susceptibility to fracture.

  20. The plant cuticle is required for osmotic stress regulation of abscisic acid biosynthesis and osmotic stress tolerance in Arabidopsis

    KAUST Repository

    Wang, Zhenyu

    2011-05-01

    Osmotic stress activates the biosynthesis of abscisic acid (ABA). One major step in ABA biosynthesis is the carotenoid cleavage catalyzed by a 9-cis epoxycarotenoid dioxygenase (NCED). To understand the mechanism for osmotic stress activation of ABA biosynthesis, we screened for Arabidopsis thaliana mutants that failed to induce the NCED3 genee xpression in response to osmotic stress treatments. The ced1 (for 9-cis epoxycarotenoid dioxy genase defective 1) mutant isolated in this study showed markedly reduced expression of NCED3 in response to osmotic stress (polyethylene glycol)treatments compared with the wild type. Other ABA biosynthesis genes are also greatly reduced in ced1 under osmotic stress. ced1 mutant plants are very sensitive to even mild osmotic stress. Map-based cloning revealed unexpectedly thatCED1 encodes a putative a/b hydrolase domain-containing protein and is allelic to the BODYGUARD gene that was recently shown to be essential for cuticle biogenesis. Further studies discovered that other cut in biosynthesis mutants are also impaired in osmotic stress induction of ABA biosynthesis genes and are sensitive to osmotic stress. Our work demonstrates that the cuticle functions not merely as a physical barrier to minimize water loss but also mediates osmotic stress signaling and tolerance by regulating ABA biosynthesis and signaling. © 2011 American Society of Plant Biologists. All rights reserved.

  1. Chitin-Hyaluronan Nanoparticles: A Multifunctional Carrier to Deliver Anti-Aging Active Ingredients through the Skin

    Directory of Open Access Journals (Sweden)

    Pierfrancesco Morganti

    2014-07-01

    Full Text Available The paper describes the process to produce Chitin Nanofibril-Hyaluronan nanoparticles (CN-HA, showing their ability to easily load active ingredients, facilitate penetration through the skin layers, and increase their effectiveness and safety as an anti-aging agent. Size and characterization of CN-HA nanoparticles were determined by Scanning Electron Microscopy (SEM and Zetasizer, while encapsulation efficiency and loading capacity of the entrapped ingredients were controlled by chromatographic and spectrophotometric methods. Safeness was evidenced on fibroblasts and keratinocytes culture viability by the MTT (Methylthiazol assay; anti-aging activity was evaluated in vitro measuring antioxidant capacity, anti-collagenase activity, and metalloproteinase and pro-inflammatory release; efficacy was shown in vivo by a double-blind vehicle-controlled study for 60 days on 60 women affected by photo-aging. In addition, the CN-HA nanoparticles have shown interesting possibility to be used as active ingredients, for designing and making advanced medication by the electrospinning technology, as well as to produce transparent films for food packaging, by the casting method, and can be used also in their dry form as tissues or films without adding preservatives. These unusual CN-HA nanoparticles obtained from the use of raw materials of waste origin may offer an unprecedented occasion for making innovative products, ameliorating the quality of life, reducing pollution and safeguarding the environment’s integrity.

  2. The effect of processing treatments on the radiation-induced ESR signal in the cuticle of irradiated Norway lobster (Nephrops norvegicus)

    International Nuclear Information System (INIS)

    Stewart, E.M.; Stevenson, M.H.; Gray, R.; McMurray, C.H.

    1993-01-01

    Cooked, frozen or chilled whole tails of Norway lobster were either not irradiated or given doses of 1, 2, 3, 4 or 5 kGy using cobalt 60 source. The cuticle was removed, freeze-dried and ground before determination of the free radical concentration using electron spin resonance (ESR) spectroscopy. The ESR signal strength increased linearly with increasing irradiation dose. In comparison to the chilled samples, cooking before irradiation significantly increased (69%) signal intensity whereas cooking after irradiation decreased (27%) signal strength. Irradiating the samples in the frozen state did not significantly alter the free radical concentration in the cuticle. (author)

  3. Aspergillus Cell Wall Chitin Induces Anti- and Proinflammatory Cytokines in Human PBMCs via the Fc-γ Receptor/Syk/PI3K Pathway

    Science.gov (United States)

    Becker, K. L.; Aimanianda, V.; Wang, X.; Gresnigt, M. S.; Ammerdorffer, A.; Jacobs, C. W.; Gazendam, R. P.; Joosten, L. A. B.; Netea, M. G.

    2016-01-01

    ABSTRACT Chitin is an important cell wall component of Aspergillus fumigatus conidia, of which hundreds are inhaled on a daily basis. Previous studies have shown that chitin has both anti- and proinflammatory properties; however the exact mechanisms determining the inflammatory signature of chitin are poorly understood, especially in human immune cells. Human peripheral blood mononuclear cells were isolated from healthy volunteers and stimulated with chitin from Aspergillus fumigatus. Transcription and production of the proinflammatory cytokine interleukin-1β (IL-1β) and the anti-inflammatory cytokine IL-1 receptor antagonist (IL-1Ra) were measured from the cell culture supernatant by quantitative PCR (qPCR) or enzyme-linked immunosorbent assay (ELISA), respectively. Chitin induced an anti-inflammatory signature characterized by the production of IL-1Ra in the presence of human serum, which was abrogated in immunoglobulin-depleted serum. Fc-γ-receptor-dependent recognition and phagocytosis of IgG-opsonized chitin was identified as a novel IL-1Ra-inducing mechanism by chitin. IL-1Ra production induced by chitin was dependent on Syk kinase and phosphatidylinositol 3-kinase (PI3K) activation. In contrast, costimulation of chitin with the pattern recognition receptor (PRR) ligands lipopolysaccharide, Pam3Cys, or muramyl dipeptide, but not β-glucan, had synergistic effects on the induction of proinflammatory cytokines by human peripheral blood mononuclear cells (PBMCs). In conclusion, chitin can have both pro- and anti-inflammatory properties, depending on the presence of pathogen-associated molecular patterns and immunoglobulins, thus explaining the various inflammatory signatures reported for chitin. PMID:27247234

  4. High electrochemical capacitor performance of oxygen and nitrogen enriched activated carbon derived from the pyrolysis and activation of squid gladius chitin

    Science.gov (United States)

    Raj, C. Justin; Rajesh, Murugesan; Manikandan, Ramu; Yu, Kook Hyun; Anusha, J. R.; Ahn, Jun Hwan; Kim, Dong-Won; Park, Sang Yeup; Kim, Byung Chul

    2018-05-01

    Activated carbon containing nitrogen functionalities exhibits excellent electrochemical property which is more interesting for several renewable energy storage and catalytic applications. Here, we report the synthesis of microporous oxygen and nitrogen doped activated carbon utilizing chitin from the gladius of squid fish. The activated carbon has large surface area of 1129 m2 g-1 with microporous network and possess ∼4.04% of nitrogen content in the form of pyridinic/pyrrolic-N, graphitic-N and N-oxide groups along with oxygen and carbon species. The microporous oxygen/nitrogen doped activated carbon is utilize for the fabrication of aqueous and flexible supercapacitor electrodes, which presents excellent electrochemical performance with maximum specific capacitance of 204 Fg-1 in 1 M H2SO4 electrolyte and 197 Fg-1 as a flexible supercapacitor. Moreover, the device displays 100% of specific capacitance retention after 25,000 subsequent charge/discharge cycles in 1 M H2SO4 electrolyte.

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

    Science.gov (United States)

    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. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

    International Nuclear Information System (INIS)

    Ponomarev, A.V.; Kholodkova, E.M.; Metreveli, A.K.; Metreveli, P.K.; Erasov, V.S.; Bludenko, A.V.; Chulkov, V.N.

    2011-01-01

    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.

  7. COMPARISON OF CHITIN STRUCTURES DERIVED FROM THREE COMMON WASP SPECIES (Vespa crabro LINNAEUS, 1758, Vespa orientalis LINNAEUS, 1771 and Vespula germanica (FABRICIUS, 1793)).

    Science.gov (United States)

    Kaya, Murat; Bağrıaçık, Nil; Seyyar, Osman; Baran, Talat

    2015-08-01

    There has been no study on the chitin structure of wasp species. Here, we selected the three most common wasp species belonging to the family Vespidae for chitin extraction and characterization. Chitin was isolated from each wasp species and characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray diffractometry (XRD), elemental analysis (EA), and scanning electron microscopy (SEM). The chitin contents of Vespa crabro, Vespa orientalis, and Vespula germanica were 8.3, 6.4, and 11.9%, respectively. The crystalline index (CrI) values for the chitin extracted from each species were 69.88, 53.92, and 50%, respectively. The most important finding of the study is that although the same method was used to extract chitin from each of the three wasp species, the degree of acetylation was different: for V. crabro and V. orientalis it was 96.85 and 99.82% (the chitin was extremely pure), respectively, whereas that for V. germanica the chitin was 79.83%. © 2015 Wiley Periodicals, Inc.

  8. Use of chitin and chitosan to produce new chitooligosaccharides by chitinase Chit42: enzymatic activity and structural basis of protein specificity

    OpenAIRE

    Kidibule, Peter E; Santos-Moriano, Paloma; Jiménez-Ortega, Elena; Ramírez-Escudero, Mercedes; Limón, M. Carmen; Remacha, Miguel; Plou Gasca, Francisco José; Sanz-Aparicio, J.; Fernández Lobato, María

    2018-01-01

    Abstract Background Chitinases are ubiquitous enzymes that have gained a recent biotechnological attention due to their ability to transform biological waste from chitin into valued chito-oligomers with wide agricultural, industrial or medical applications. The biological activity of these molecules is related to their size and acetylation degree. Chitinase Chit42 from Trichoderma harzianum hydrolyses chitin oligomers with a minimal of t...

  9. Soil water stress affects both cuticular wax content and cuticle-related gene expression in young saplings of maritime pine (Pinus pinaster Ait).

    Science.gov (United States)

    Le Provost, Grégoire; Domergue, Frédéric; Lalanne, Céline; Ramos Campos, Patricio; Grosbois, Antoine; Bert, Didier; Meredieu, Céline; Danjon, Frédéric; Plomion, Christophe; Gion, Jean-Marc

    2013-07-01

    The cuticle is a hydrophobic barrier located at the aerial surface of all terrestrial plants. Recent studies performed on model plants, such as Arabidopsis thaliana, have suggested that the cuticle may be involved in drought stress adaptation, preventing non-stomatal water loss. Although forest trees will face more intense drought stresses (in duration and intensity) with global warming, very few studies on the role of the cuticle in drought stress adaptation in these long-lived organisms have been so far reported. This aspect was investigated in a conifer, maritime pine (Pinus pinaster Ait.), in a factorial design with two genetic units (two half-sib families with different growth rates) and two treatments (irrigated vs non-irrigated), in field conditions. Saplings were grown in an open-sided greenhouse and half were irrigated three times per week for two growing seasons. Needles were sampled three times per year for cuticular wax (composition and content) and transcriptome (of 11 genes involved in cuticle biosynthesis) analysis. Non-irrigated saplings (i) had a higher cuticular wax content than irrigated saplings and (ii) overexpressed most of the genes studied. Both these trends were more marked in the faster growing family. The higher cuticular wax content observed in the non-irrigated treatment associated with strong modifications in products from the decarbonylation pathway suggest that cuticular wax may be involved in drought stress adaptation in maritime pine. This study provides also a set of promising candidate genes for future forward genetic studies in conifers.

  10. Primary structure of a 14 kDa basic structural protein (Lm-76) from the cuticle of the migratory locust, Locusta migratoria

    DEFF Research Database (Denmark)

    Andersen, Jens S.; Andersen, S O; Højrup, P

    1993-01-01

    The complete amino acid sequence of a 14 kDa structural protein (LM-76) isolated from pharate cuticle of the locust, Locusta migratoria, was determined by Edman degradation of the intact protein and enzymatically derived peptides. Plasma desorption and electrospray mass spectrometry was used as a...

  11. Surface-Initiated Graft Atom Transfer Radical Polymerization of Methyl Methacrylate from Chitin Nanofiber Macroinitiator under Dispersion Conditions

    Directory of Open Access Journals (Sweden)

    Ryo Endo

    2015-08-01

    Full Text Available Surface-initiated graft atom transfer radical polymerization (ATRP of methyl methacrylate (MMA from self-assembled chitin nanofibers (CNFs was performed under dispersion conditions. Self-assembled CNFs were initially prepared by regeneration from a chitin ion gel with 1-allyl-3-methylimidazolium bromide using methanol; the product was then converted into the chitin nanofiber macroinitiator by reaction with α-bromoisobutyryl bromide in a dispersion containing N,N-dimethylformamide. Surface-initiated graft ATRP of MMA from the initiating sites on the CNFs was subsequently carried out under dispersion conditions, followed by filtration to obtain the CNF-graft-polyMMA film. Analysis of the product confirmed the occurrence of the graft ATRP on the surface of the CNFs.

  12. Inhibition of chitin biosynthesis in cultured imaginal discs: Effects of alpha-amanitin, actinomycin-D, cycloheximide, and puromycin.

    Science.gov (United States)

    Oberlander, Herbert; Ferkovich, Stephen; Leach, Eddie; Van Essen, Frank

    1980-02-01

    Wing imaginal discs isolated from last instar larvae of the Indian meal moth,Plodia interpunctella, produced chitin when incubated in vitro with ≧2×10 -7 M 20-hydroxyecdysone. Chitin biosynthesis was initiated 8 h after the conclusion of a 24-h treatment with hormone. Simulataneous incubation of wing discs with 20-hydroxyecdysone and either inhibitors of RNA synthesis (alpha-amanitin, actinomycin-D) or inhibitors of protein systhesis (cycloheximide, puromycin) prevented chitin biosynthesis. We conclude from our results that RNA and protein synthesis must continue undiminished during the hormone-contact period, and that synthesis of protein, but not of new RNA is required during the posthormone culture period. Our findings are consistent with the hypothesis that ecdysteroids stimulate insect metamorphosis by promoting the synthesis of new RNA and protein during a hormone-dependent phase followed by hormone-independent protein synthesis.

  13. Bioremediation of crude oil polluted seawater by a hydrocarbon-degrading bacterial strain immobilized on chitin and chitosan flakes

    International Nuclear Information System (INIS)

    Gentili, A.R.; Cubitto, M.A.; Ferrero, M.; Rodriguez, M.S.

    2006-01-01

    In this laboratory-scale study, we examined the potential of chitin and chitosan flakes obtained from shrimp wastes as carrier material for a hydrocarbon-degrading bacterial strain. Flakes decontamination, immobilization conditions and the survival of the immobilized bacterial strain under different storage temperatures were evaluated. The potential of immobilized hydrocarbon-degrading bacterial strain for crude oil polluted seawater bioremediation was tested in seawater microcosms. In terms of removal percentage of crude oil after 15 days, the microcosms treated with the immobilized inoculants proved to be the most successful. The inoculants formulated with chitin and chitosan as carrier materials improved the survival and the activity of the immobilized strain. It is important to emphasize that the inoculants formulated with chitin showed the best performance during storage and seawater bioremediation. (author)

  14. Albizia lebbeck Seed Coat Proteins Bind to Chitin and Act as a Defense against Cowpea Weevil Callosobruchus maculatus.

    Science.gov (United States)

    Silva, Nadia C M; De Sá, Leonardo F R; Oliveira, Eduardo A G; Costa, Monique N; Ferreira, Andre T S; Perales, Jonas; Fernandes, Kátia V S; Xavier-Filho, Jose; Oliveira, Antonia E A

    2016-05-11

    The seed coat is an external tissue that participates in defense against insects. In some nonhost seeds, including Albizia lebbeck, the insect Callosobruchus maculatus dies during seed coat penetration. We investigated the toxicity of A. lebbeck seed coat proteins to C. maculatus. A chitin-binding protein fraction was isolated from seed coat, and mass spectrometry showed similarity to a C1 cysteine protease. By ELM program an N-glycosylation interaction motif was identified in this protein, and by molecular docking the potential to interact with N-acetylglucosamine (NAG) was shown. The chitin-binding protein fraction was toxic to C. maculatus and was present in larval midgut and feces but not able to hydrolyze larval gut proteins. It did not interfere, though, with the intestinal cell permeability. These results indicate that the toxicity mechanism of this seed coat fraction may be related to its binding to chitin, present in the larvae gut, disturbing nutrient absorption.

  15. 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)

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

    Science.gov (United States)

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

    2014-01-01

    Hepatic carcinoma (HCC) is one of the most common cancer and its treatment has been considered a therapeutic challenge. Doxorubicin (Dox) is one of the most important chemotherapeutic agents used in the treatment for liver cancer. However, the efficacy of Dox therapy is restricted by the dose-dependent toxic side effects. To overcome the cardiotoxicity of Dox as well as the current problems of conventional modality treatment of HCC, we developed a locally injectable, biodegradable, and pH sensitive composite nanogels for site specific delivery. Both control and Dox loaded composite nanogel systems were analyzed by DLS, SEM, FTIR and TG/DTA. The size ranges of the control composite nanogels and their drug loaded counterparts were found to be 90±20 and 270±20 nm, respectively. The control chitin-PLA CNGs and Dox-chitin-PLA CNGs showed higher swelling and degradation in acidic pH. Drug entrapment efficiency and in vitro drug release studies were carried out and showed a higher drug release at acidic pH compared to neutral pH. Cellular internalization of the nanogel systems was confirmed by fluorescent microscopy. The cytotoxicity of the composite nanogels was analyzed toward HepG2 (human liver cancer) cell lines. Furthermore, the results of in vitro hemolytic assay and coagulation assay substantiate the blood compatibility of the system. Overall Dox-chitin-PLA CNGs system could be a promising anticancer drug delivery system for liver cancer therapy. Copyright © 2013 Elsevier B.V. All rights reserved.

  17. 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.

  18. 3D printing human induced pluripotent stem cells with novel hydroxypropyl chitin bioink: scalable expansion and uniform aggregation.

    Science.gov (United States)

    Li, Yang; Jiang, Xulin; Li, Ling; Chen, Zhi-Nan; Gao, Ge; Yao, Rui; Sun, Wei

    2018-06-28

    Human induced pluripotent stem cells (hiPSCs) are more likely to successfully avoid the immunological rejection and ethical problems that are often encountered by human embryonic stem cells in various stem cell studies and applications. To transfer hiPSCs from the laboratory to clinical applications, researchers must obtain sufficient cell numbers. In this study, 3D cell printing was used as a novel method for iPSC scalable expansion. Hydroxypropyl chitin (HPCH), utilized as a new type of bioink, and a set of optimized printing parameters were shown to achieve high cell survival (> 90%) after the printing process and high proliferation efficiency (~ 32.3 folds) during subsequent 10-day culture. After the culture, high levels of pluripotency maintenance were recognized by both qualitative and quantitative detections. Compared with static suspension (SS) culture, hiPSC aggregates formed in 3D printed constructs showed a higher uniformity in size. Using novel dual-fluorescent labelling method, hiPSC aggregates in the constructs were found more inclined to form by in situ proliferation rather than multicellular aggregation. This study revealed unique advantages of non-ionic crosslinking bioink material HPCH, including high gel strength and rapid temperature response in hiPSC printing, and achieved primed state hiPSC printing for the first time. Features achieved in this study, such as high cell yield, high pluripotency maintenance and uniform aggregation provide good foundations for further hiPSC studies on 3D micro-tissue differentiation and drug screening. © 2018 IOP Publishing Ltd.

  19. From chitin to bioactive chitooligosaccharides and conjugates: access to lipochitooligosaccharides and the TMG-chitotriomycin.

    Science.gov (United States)

    Despras, Guillaume; Alix, Aurélien; Urban, Dominique; Vauzeilles, Boris; Beau, Jean-Marie

    2014-10-27

    The direct and chemoselective N-transacylation of peracetylated chitooligosaccharides (COSs), readily obtained from chitin, to give per-N-trifluoroacetyl derivatives offers an attractive route to size-defined COSs and derived glycoconjugates. It involves the use of various acceptor building blocks and trifluoromethyl oxazoline dimer donors prepared with efficiency and highly reactive in 1,2-trans glycosylation reactions. This method was applied to the preparation of the important symbiotic glycolipids which are highly active on plants and to the TMG-chitotriomycin, a potent and specific inhibitor of insect, fungal, and bacterial N-acetylglucosaminidases. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

    Science.gov (United States)

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

    2016-08-20

    We investigated the effects of chitin nano-whiskers (CNWs) on the antibacterial and physiochemical properties of maize starch-based films. The microstructures, crystalline structures, and thermal, mechanical and barrier properties of the nanocomposite films were characterized by using transmission electron microscopy, X-ray diffraction analysis, thermogravimetric, differential scanning calorimeter, and texture profile analysis. The tensile strength of the maize starch films increased from 1.64MPa to 3.69MPa (Pstarch films. Furthermore, the nanocomposite films exhibited strong antimicrobial activity against Gram-positive Listeria monocytogenes but not against Gram-negative Escherichia coli. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

    DEFF Research Database (Denmark)

    Müller, Christian; Hansen, K.; Szabo, Peter

    2003-01-01

    The objective of this study was to quantify the effect of disrupting two chitin synthases, chsB and csmA, on the morphology and rheology during batch cultivation of Aspergillus oryzae. The rheological properties were characterized in batch cultivations at different biomass concentrations (from 3...... broth was significantly affected by the biomass concentration, the morphology, and also by pH. The chsB disruption strain had lower consistency index K values for all biomass concentrations investigated, which is a desirable trait for industrial Aspergillus fermentations. (C) 2003 Wiley Periodicals, Inc....

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

    Directory of Open Access Journals (Sweden)

    Maria Izabel Gallão

    2010-04-01

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

  3. An Endosperm-Associated Cuticle Is Required for Arabidopsis Seed Viability, Dormancy and Early Control of Germination.

    Directory of Open Access Journals (Sweden)

    Julien De Giorgi

    2015-12-01

    Full Text Available Cuticular layers and seeds are prominent plant adaptations to terrestrial life that appeared early and late during plant evolution, respectively. The cuticle is a waterproof film covering plant aerial organs preventing excessive water loss and protecting against biotic and abiotic stresses. Cutin, consisting of crosslinked fatty acid monomers, is the most abundant and studied cuticular component. Seeds are dry, metabolically inert structures promoting plant dispersal by keeping the plant embryo in an arrested protected state. In Arabidopsis thaliana seeds, the embryo is surrounded by a single cell endosperm layer itself surrounded by a seed coat layer, the testa. Whole genome analyses lead us to identify cutin biosynthesis genes as regulatory targets of the phytohormones gibberellins (GA and abscisic acid (ABA signaling pathways that control seed germination. Cutin-containing layers are present in seed coats of numerous species, including Arabidopsis, where they regulate permeability to outer compounds. However, the role of cutin in mature seed physiology and germination remains poorly understood. Here we identify in mature seeds a thick cuticular film covering the entire outer surface of the endosperm. This seed cuticle is defective in cutin-deficient bodyguard1 seeds, which is associated with alterations in endospermic permeability. Furthermore, mutants affected in cutin biosynthesis display low seed dormancy and viability levels, which correlates with higher levels of seed lipid oxidative stress. Upon seed imbibition cutin biosynthesis genes are essential to prevent endosperm cellular expansion and testa rupture in response to low GA synthesis. Taken together, our findings suggest that in the course of land plant evolution cuticular structures were co-opted to achieve key physiological seed properties.

  4. 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.

  5. Darker eggs of mosquitoes resist more to dry conditions: Melanin enhances serosal cuticle contribution in egg resistance to desiccation in Aedes, Anopheles and Culex vectors.

    Science.gov (United States)

    Farnesi, Luana C; Vargas, Helena C M; Valle, Denise; Rezende, Gustavo L

    2017-10-01

    Mosquito vectors lay their white eggs in the aquatic milieu. During early embryogenesis water passes freely through the transparent eggshell, which at this moment is composed of exochorion and endochorion. Within two hours the endochorion darkens via melanization but even so eggs shrink and perish if removed from moisture. However, during mid-embryogenesis, cells of the extraembryonic serosa secrete the serosal cuticle, localized right below the endochorion, becoming the third and innermost eggshell layer. Serosal cuticle formation greatly reduces water flow and allows egg survival outside the water. The degree of egg resistance to desiccation (ERD) at late embryogenesis varies among different species: Aedes aegypti, Anopheles aquasalis and Culex quinquefasciatus eggs can survive in a dry environment for ≥ 72, 24 and 5 hours, respectively. In some adult insects, darker-body individuals show greater resistance to desiccation than lighter ones. We asked if egg melanization enhances mosquito serosal cuticle-dependent ERD. Species with higher ERD at late embryogenesis exhibit more melanized eggshells. The melanization-ERD hypothesis was confirmed employing two Anopheles quadrimaculatus strains, the wild type and the mutant GORO, with a dark-brown and a golden eggshell, respectively. In all cases, serosal cuticle formation is fundamental for the establishment of an efficient ERD but egg viability outside the water is much higher in mosquitoes with darker eggshells than in those with lighter ones. The finding that pigmentation influences egg water balance is relevant to understand the evolutionary history of insect egg coloration. Since eggshell and adult cuticle pigmentation ensure insect survivorship in some cases, they should be considered regarding species fitness and novel approaches for vector or pest insects control.

  6. 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

  7. Identification of GIG1, a GlcNAc-induced gene in Candida albicans needed for normal sensitivity to the chitin synthase inhibitor nikkomycin Z.

    Science.gov (United States)

    Gunasekera, Angelo; Alvarez, Francisco J; Douglas, Lois M; Wang, Hong X; Rosebrock, Adam P; Konopka, James B

    2010-10-01

    The amino sugar N-acetylglucosamine (GlcNAc) is known to be an important structural component of cells from bacteria to humans, but its roles in cell signaling are less well understood. GlcNAc induces two pathways in the human fungal pathogen Candida albicans. One activates cyclic AMP (cAMP) signaling, which stimulates the formation of hyphal cells and the expression of virulence genes, and the other pathway induces genes needed to catabolize GlcNAc. Microarray analysis of gene expression was carried out under four different conditions in order to characterize the transcriptional changes induced by GlcNAc. The most highly induced genes include those that encode a GlcNAc transporter (NGT1) and the GlcNAc catabolic enzymes (HXK1, DAC1, and NAG1). GlcNAc also activated most of the genes whose expression is increased when cells are triggered with other stimuli to form hyphae. Surprisingly, GlcNAc also induced a subset of genes that are regulated by galactose (GAL1, GAL7, and GAL10), which may be due to cross talk between signaling pathways. A novel GlcNAc-induced gene, GIG1, which is not essential for GlcNAc catabolism or the induction of hyphae, was identified. However, a Gig1-green fluorescent protein (GFP) fusion protein was specifically induced by GlcNAc, and not by other sugars. Gig1-GFP localized to the cytoplasm, where GlcNAc metabolism occurs. Significantly, a gig1Δ mutant displayed increased resistance to nikkomycin Z, which inhibits chitin synthase from converting UDP-GlcNAc into cell wall chitin. Gig1 is highly conserved in fungi, especially those that contain GlcNAc catabolic genes. These results implicate Gig1 in GlcNAc metabolism.

  8. Identification of GIG1, a GlcNAc-Induced Gene in Candida albicans Needed for Normal Sensitivity to the Chitin Synthase Inhibitor Nikkomycin Z▿§

    Science.gov (United States)

    Gunasekera, Angelo; Alvarez, Francisco J.; Douglas, Lois M.; Wang, Hong X.; Rosebrock, Adam P.; Konopka, James B.

    2010-01-01

    The amino sugar N-acetylglucosamine (GlcNAc) is known to be an important structural component of cells from bacteria to humans, but its roles in cell signaling are less well understood. GlcNAc induces two pathways in the human fungal pathogen Candida albicans. One activates cyclic AMP (cAMP) signaling, which stimulates the formation of hyphal cells and the expression of virulence genes, and the other pathway induces genes needed to catabolize GlcNAc. Microarray analysis of gene expression was carried out under four different conditions in order to characterize the transcriptional changes induced by GlcNAc. The most highly induced genes include those that encode a GlcNAc transporter (NGT1) and the GlcNAc catabolic enzymes (HXK1, DAC1, and NAG1). GlcNAc also activated most of the genes whose expression is increased when cells are triggered with other stimuli to form hyphae. Surprisingly, GlcNAc also induced a subset of genes that are regulated by galactose (GAL1, GAL7, and GAL10), which may be due to cross talk between signaling pathways. A novel GlcNAc-induced gene, GIG1, which is not essential for GlcNAc catabolism or the induction of hyphae, was identified. However, a Gig1-green fluorescent protein (GFP) fusion protein was specifically induced by GlcNAc, and not by other sugars. Gig1-GFP localized to the cytoplasm, where GlcNAc metabolism occurs. Significantly, a gig1Δ mutant displayed increased resistance to nikkomycin Z, which inhibits chitin synthase from converting UDP-GlcNAc into cell wall chitin. Gig1 is highly conserved in fungi, especially those that contain GlcNAc catabolic genes. These results implicate Gig1 in GlcNAc metabolism. PMID:20675577

  9. 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

    2012-01-01

    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. PMID:23024043

  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. 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

    2014-11-26

    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. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  12. Chitin and Cellulose Processing in Low-Temperature Electron Beam Plasma

    Directory of Open Access Journals (Sweden)

    Tatiana Vasilieva

    2017-11-01

    Full Text Available Polysaccharide processing by means of low-temperature Electron Beam Plasma (EBP is a promising alternative to the time-consuming and environmentally hazardous chemical hydrolysis in oligosaccharide production. The present paper considers mechanisms of the EBP-stimulated destruction of crab shell chitin, cellulose sulfate, and microcrystalline cellulose, as well as characterization of the produced oligosaccharides. The polysaccharide powders were treated in oxygen EBP for 1–20 min at 40 °C in a mixing reactor placed in the zone of the EBP generation. The chemical structure and molecular mass of the oligosaccharides were analyzed by size exclusion and the reversed phase chromatography, FTIR-spectroscopy, XRD-, and NMR-techniques. The EBP action on original polysaccharides reduces their crystallinity index and polymerization degree. Water-soluble products with lower molecular weight chitooligosaccharides (weight-average molecular mass, Mw = 1000–2000 Da and polydispersity index 2.2 and cellulose oligosaccharides with polymerization degrees 3–10 were obtained. The 1H-NMR analysis revealed 25–40% deacetylation of the EBP-treated chitin and FTIR-spectroscopy detected an increase of carbonyl- and carboxyl-groups in the oligosaccharides produced. Possible reactions of β-1,4-glycosidic bonds’ destruction due to active oxygen species and high-energy electrons are given.

  13. Immobilization of metal hexa-cyanoferrates in chitin beads for cesium sorption: synthesis and characterization

    International Nuclear Information System (INIS)

    Vincent, T.; Guibal, E.; Vincent, C.; Barre, Y.; Guari, Y.; Le Saout, G.

    2014-01-01

    Five metal-potassium hexacyanoferrate/chitin composites (based on Cu, Ni, Zn, Co or Fe co-metal) have been prepared and characterized, using SEM-EDX, TEM, X-ray diffraction and FT-IR, before being compared for Cs(I) and 137 Cs(I) sorption. The Zn-ion exchanger was characterized by a much larger crystal size of about 250 nm compared with a few tens of nm for other ion-exchangers. The ion exchangers are well distributed in the whole mass of the composite and they are fully accessible to Cs(I), as evidenced by Cs(I) distribution after metal sorption. Uptake kinetics can be modeled using both the pseudo-second order rate equation and the Crank equation (resistance to intra-particle diffusion coefficient). Sorption isotherms showed substantial differences in the sorbents that can be ranked as Cu ≥ Ni ≥ Zn ≥ Co ≥ Fe. However, based on 137 Cs K d values, the sorbents can be ranked as Co≥≥Fe≥≥Cu≥≥Ni≥Zn. Taking into account the cost and toxicity of metals (both in terms of manufacturing and potential metal release) a Prussian Blue based sorbent (i.e., iron-potassium hexacyanoferrate/chitin composite) sounds to be a good composite for Cs(I) recovery from radionuclide-containing effluents. (authors)

  14. Chitin nanofibrils for rapid and efficient removal of metal ions from water system.

    Science.gov (United States)

    Liu, Dagang; Zhu, Yi; Li, Zehui; Tian, Donglin; Chen, Lei; Chen, Peng

    2013-10-15

    Joint mechanical defibrillation was successfully used to downsize chitin micro-particles (CMP) into nanofibrils without changing its chemical or crystalline structure. The fine chitin nanofibrils (CNF) bearing width of about 50 nm and length of more than 1 μm were then developed as heavy metal ion sorbents. The uptake performance of CNF dependent on pH, ionic concentration, time, and temperature was investigated. Results show that fixation amount of Cd(II), Ni(II), Cu(II), Zn(II), Pb(II), Cr(III) on CNF was up to 2.94, 2.30, 2.22, 2.06, 1.46, and 0.31 mmol/g, respectively, much higher than CMP due to high specific surface area and widely distributed pores of CNF. Adsorption kinetics of CMP and CNF followed pseudo-second-order model and Freundlich isotherm although CNF exhibited higher rate constant and sorption capacity than that of CMP. The defibrillated CNF is renewable, feasible, easily recyclable, and is thought as good candidate for heavy metal ion treatment due to their low sorption energy, rapid and efficient uptake capacity. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Fabrication of thermoplastic ductile films of chitin butyrate/poly(ɛ-caprolactone) blends and their cytocompatibility.

    Science.gov (United States)

    Hashiwaki, Hiroki; Teramoto, Yoshikuni; Nishio, Yoshiyuki

    2014-12-19

    We fabricate thermoplastic films of chitin burtyrate (ChB)/poly(ɛ-caprolactone) (PCL) blends with different degree of miscibility (miscible (M), partially miscible (PM), and immiscible (IM)), and examined the feasibility as a cell scaffold system through evaluating mechanical properties and cytocompatibility. We found a remediation of the brittleness and an increase in ductility of ChB by blending PCL for the M and PM blends. The blend films were subjected to alkaline hydrolysis (2-M NaOH/37°C/48 h) with expectation of the improvement of the surface hydrophilicity and cell accessibility. ATR-FTIR spectroscopy of the alkaline-treated PM and IM films revealed that PCL component and ester side-chains of acyl chitin were selectively removed from the surface domain. L929 fibroblast cells well adhered and proliferated on these films. Therefore, the materials possess a great potential for the utilization as a thermoplastic cell scaffold in tissue engineering by adequate selection of the degree of miscibility and post treatment. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Reclamation of Marine Chitinous Materials for the Production of α-Glucosidase Inhibitors via Microbial Conversion

    Directory of Open Access Journals (Sweden)

    Van Bon Nguyen

    2017-11-01

    Full Text Available Six kinds of chitinous materials have been used as sole carbon/nitrogen (C/N sources for producing α-glucosidase inhibitors (aGI by Paenibacillus sp. TKU042. The aGI productivity was found to be highest in the culture supernatants using demineralized crab shell powder (deCSP and demineralized shrimp shell powder (deSSP as the C/N source. The half maximal inhibitory concentration (IC50 and maximum aGI activity of fermented deCSP (38 µg/mL, 98%, deSSP (108 µg/mL, 89%, squid pen powder (SPP (422 µg/mL, 98%, and shrimp head powder (SHP (455 µg/mL, 92% were compared with those of fermented nutrient broth (FNB (81 µg/mL, 93% and acarbose (1095 µg/mL, 74%, a commercial antidiabetic drug. The result of the protein/chitin ratio on aGI production showed that the optimal ratio was 0.2/1. Fermented deCSP showed lower IC50 and higher maximum inhibitory activity than those of acarbose against rat intestinal α-glucosidase.

  17. Teaching Form as Form

    DEFF Research Database (Denmark)

    Keiding, Tina Bering

    2012-01-01

    understanding of form per se, or, to use an expression from this text, of form as form. This challenge can be reduced to one question: how can design teaching support students in achieving not only the ability to recognize and describe different form-related concepts in existing design (i.e. analytical...

  18. Cloning of cDNA sequences encoding cowpea (Vigna unguiculata) vicilins: Computational simulations suggest a binding mode of cowpea vicilins to chitin oligomers.

    Science.gov (United States)

    Rocha, Antônio J; Sousa, Bruno L; Girão, Matheus S; Barroso-Neto, Ito L; Monteiro-Júnior, José E; Oliveira, José T A; Nagano, Celso S; Carneiro, Rômulo F; Monteiro-Moreira, Ana C O; Rocha, Bruno A M; Freire, Valder N; Grangeiro, Thalles B

    2018-05-27

    Vicilins are 7S globulins which constitute the major seed storage proteins in leguminous species. Variant vicilins showing differential binding affinities for chitin have been implicated in the resistance and susceptibility of cowpea to the bruchid Callosobruchus maculatus. These proteins are members of the cupin superfamily, which includes a wide variety of enzymes and non-catalytic seed storage proteins. The cupin fold does not share similarity with any known chitin-biding domain. Therefore, it is poorly understood how these storage proteins bind to chitin. In this work, partial cDNA sequences encoding β-vignin, the major component of cowpea vicilins, were obtained from developing seeds. Three-dimensional molecular models of β-vignin showed the characteristic cupin fold and computational simulations revealed that each vicilin trimer contained 3 chitin-binding sites. Interaction models showed that chito-oligosaccharides bound to β-vignin were stabilized mainly by hydrogen bonds, a common structural feature of typical carbohydrate-binding proteins. Furthermore, many of the residues involved in the chitin-binding sites of β-vignin are conserved in other 7S globulins. These results support previous experimental evidences on the ability of vicilin-like proteins from cowpea and other leguminous species to bind in vitro to chitin as well as in vivo to chitinous structures of larval C. maculatus midgut. Copyright © 2018. Published by Elsevier B.V.

  19. Systematic dynamic viscoelasticity measurements for chitin nanofibers prepared with various concentrations, disintegration times, acidities, and crystalline structures.

    Science.gov (United States)

    Suenaga, Shin; Osada, Mitsumasa

    2018-04-17

    Dynamic viscoelasticities were measured for chitin nanofiber (ChNF) dispersions prepared with various concentrations, disintegration times, acidities, and crystalline structures. The 0.05 w/v% dispersions of pH neutral ChNFs continuously exhibited elastic behavior. The 0.05 w/v% dispersions of acidified ChNFs, on the other hand, transitioned from a colloidal dispersion to a critical gel and then exhibited elastic behavior with increasing ChNF concentration. A double-logarithmic chart of the concentration vs. the storage modulus was prepared and indicated the fractal dimension and the nanostructure in the dispersion. The results determined that the neutral α- and β-ChNFs were dispersed but showed some remaining aggregations and that the acidified β-ChNFs were completely individualized. In addition, the α-chitin steadily disintegrated with increasing disintegration time, and the aspect ratio of the β-chitin decreased as a result of the exscessive disintegration. The storage moduli of the ChNFs were greater than those of chitin solutions, nanorods, and nanowhiskers with the same solids concentrations. Copyright © 2018 Elsevier B.V. All rights reserved.

  20. Chitin-hyaluronan nanoparticles: a multifunctional carrier to deliver anti-aging active ingredients through the skin

    Czech Academy of Sciences Publication Activity Database

    Morganti, P.; Palombo, M.; Tishchenko, Galina; Yudin, V. E.; Guarneri, F.; Cardillo, M.; Del Ciotto, P.; Carezzi, F.; Morganti, G.; Fabrizi, G.

    2014-01-01

    Roč. 1, č. 3 (2014), s. 140-158 ISSN 2079-9284 EU Projects: European Commission(XE) 315233 - N-CHITOPACK Institutional support: RVO:61389013 Keywords : chitin nanofibrils * skin aging emulsions * innovative beauty masks Subject RIV: CD - Macromolecular Chemistry

  1. Films of chitin, chitosan and cellulose obtained from aqueous suspension treated by irradiation of high intensity ultrasound

    International Nuclear Information System (INIS)

    Almeida, Erika V.R.; Mariano, Mario S.; Campana-Filho, Sergio P.

    2011-01-01

    Films of chitin, chitin/chitosan and chitin/sisal cellulose were obtained by casting their aqueous suspensions previously treated with irradiation of high intensity ultrasound. The films were characterized for surface morphology by scanning electron microscopy and it is possible notice that the films containing chitosan are much more homogeneous. The thermal behavior of the films was evaluated by dynamic mechanical thermal analysis, differential scanning calorimetry, and thermogravimetric analysis and revealing similarity in comparison with the thermal behavior of polysaccharide isolated. The tensile strength was determined and the film containing chitosan showed the best result when compared to other films. The crystallinity index of the films analyzed by X-ray diffraction showed that the films are amorphous material. The analysis by infrared spectroscopy showed that treatment of aqueous suspensions of polysaccharides with irradiation of high intensity ultrasound did not change the chemical structure of polymers. The crystallinity index was determined by X-ray diffraction, revealing that the films are amorphous materials. The results of this study indicate the possibility of processing of chitin, chitosan and cellulose, polysaccharides whose solubilities are limited to a few solvent systems, by treating their aqueous suspensions with high intensity ultrasound. (author)

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

    NARCIS (Netherlands)

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

    2015-01-01

    The abundant polymer chitin can be degraded by chitinases (EC 3.2.1.14) and beta-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

  3. Improved fluorescent labeling of chitin oligomers: Chitinolytic properties of acidic mammalian chitinase under somatic tissue pH conditions.

    Science.gov (United States)

    Wakita, Satoshi; Kimura, Masahiro; Kato, Naoki; Kashimura, Akinori; Kobayashi, Shunsuke; Kanayama, Naoto; Ohno, Misa; Honda, Shotaro; Sakaguchi, Masayoshi; Sugahara, Yasusato; Bauer, Peter O; Oyama, Fumitaka

    2017-05-15

    Acidic mammalian chitinase (AMCase) has been implicated in various pathophysiological conditions including asthma, allergic inflammation and food processing. AMCase is most active at pH 2.0, and its activity gradually decreases to up to pH 8. Here we analyzed chitin degradation by AMCase in weak acidic to neutral conditions by fluorophore-assisted carbohydrate electrophoresis established originally for oligosaccharides analysis. We found that specific fragments with slower-than-expected mobility as defined by chitin oligosaccharide markers were generated at pH 5.0∼8.0 as by-products of the reaction. We established an improved method for chitin oligosaccharides suppressing this side reaction by pre-acidification of the fluorophore-labeling reaction mixture. Our improved method specifically detects chitin oligosaccharides and warrants quantification of up to 50nmol of the material. Using this strategy, we found that AMCase produced dimer of N-acetyl-d-glucosamine (GlcNAc) at strong acidic to neutral condition. Moreover, we found that AMCase generates (GlcNAc) 2 as well as (GlcNAc) 3 under physiological conditions. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

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

    NARCIS (Netherlands)

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

    2012-01-01

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

  5. Extração, estruturas e propriedades de alfa- e beta-quitina Extraction, structures and properties of alpha- AND beta-chitin

    Directory of Open Access Journals (Sweden)

    Sergio P. Campana-Filho

    2007-06-01

    Full Text Available The fact that alpha- and beta-chitin adopt different arrays in the solid state is explored to emphasize their different properties and distinct spectral characteristics and X ray diffraction patterns. The methods for their extraction from the biomass in view of the preservation of their native structures and aiming to fulfill the claims of purity and uniformity for potential applications are discussed. The different arrays adopted by alpha- and beta-chitin also result in distinct reactivities toward the deacetylation reaction. Thus, the deacetylation of beta-chitin is more efficient owing to the better accessibility to amide groups due to the lower crystallinity of this polymorph.

  6. Effect of some biological factors on the chitin yield of two crustacean species inhabiting the Egyptian waters

    Directory of Open Access Journals (Sweden)

    Amira Talaat Abo-Hashesh

    2017-11-01

    Full Text Available Objective: To investigate the chitin yield of two commercial crustacean species that are exploited in the Suez Canal region, the Red Sea crab Charybdis natator (C. natator and the Mediterranean mantis shrimp Erugosquilla massavensis (E. massavensis, and to assess the effect of some biological factors such as sex, size and maturity stages of females' ovaries on this yield. Methods: A total of 64 specimens of crabs were collected from the Red Sea and 1 377 mantis shrimps were collected from the Mediterranean Sea. Chitin was obtained after the deproteinization, de-mineralization and de-colorization of 5 g oven dried exoskeletons and values were expressed as g/5 g and percentages. Results: Chitin yield was significantly higher in E. massavensis than C. natator (22.1%, 14.22%, respectively. No significant difference in the yield was recorded between males and females of C. natator (12.9%, 14.9%, respectively, while the yield in E. massavensis males was significantly higher than females (25.3%, 21.2%, respectively. Significant variations in the chitin yield were observed between the different sizes of E. massavensis with the maximum being from the individuals falling in the size range 90–130 mm body length. The yield was at its lowest in the immature stage of C. natator females' ovaries (9.29%. However, the values increased and remained constant for the remaining stages (≥ 18%. Conclusions: The study recommends the use of the mantis shrimp for the production of chitin on commercial scale particularly medium sized males.

  7. 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.

  8. Chitin mixed in potting soil alters lettuce growth, the survival of zoonotic bacteria on the leaves and associated rhizosphere microbiology.

    Directory of Open Access Journals (Sweden)

    Jane eDebode

    2016-04-01

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

  9. Morintides: cargo-free chitin-binding peptides from Moringa oleifera.

    Science.gov (United States)

    Kini, Shruthi G; Wong, Ka H; Tan, Wei Liang; Xiao, Tianshu; Tam, James P

    2017-03-31

    Hevein-like peptides are a family of cysteine-rich and chitin-binding peptides consisting of 29-45 amino acids. Their chitin-binding property is essential for plant defense against fungi. Based on the number of cysteine residues in their sequences, they are divided into three sub-families: 6C-, 8C- and 10C-hevein-like peptides. All three subfamilies contain a three-domain precursor comprising a signal peptide, a mature hevein-like peptide and a C-terminal domain comprising a hinge region with protein cargo in 8C- and 10C-hevein-like peptides. Here we report the isolation and characterization of two novel 8C-hevein-like peptides, designated morintides (mO1 and mO2), from the drumstick tree Moringa oleifera, a drought-resistant tree belonging to the Moringaceae family. Proteomic analysis revealed that morintides comprise 44 amino acid residues and are rich in cysteine, glycine and hydrophilic amino acid residues such as asparagine and glutamine. Morintides are resistant to thermal and enzymatic degradation, able to bind to chitin and inhibit the growth of phyto-pathogenic fungi. Transcriptomic analysis showed that they contain a three-domain precursor comprising an endoplasmic reticulum (ER) signal sequence, a mature peptide domain and a C-terminal domain. A striking feature distinguishing morintides from other 8C-hevein-like peptides is a short and protein-cargo-free C-terminal domain. Previously, a similar protein-cargo-free C-terminal domain has been observed only in ginkgotides, the 8C-hevein-like peptides from a gymnosperm Ginkgo biloba. Thus, morintides, with a cargo-free C-terminal domain, are a stand-alone class of 8C-hevein-like peptides from angiosperms. Our results expand the existing library of hevein-like peptides and shed light on molecular diversity within the hevein-like peptide family. Our work also sheds light on the anti-fungal activity and stability of 8C-hevein-like peptides.

  10. Inter- and intra-specific cuticle variation between amphimictic and parthenogenetic species of root-knot nematode (Meloidogyne spp.) as revealed by a bacterial parasite (Pasteuria penetrans).

    Science.gov (United States)

    Davies, K G; Rowe, J A; Williamson, V M

    2008-06-01

    Specific host-parasite interactions exist between species and strains of plant parasitic root-knot nematodes and the Gram-positive bacterial hyperparasite Pasteuria penetrans. This bacterium produces endospores that adhere to the cuticle of migrating juveniles, germinate and colonise the developing female within roots. Endospore attachment of P. penetrans populations to second-stage juveniles of the root-knot nematode species Meloidogyne incognita and Meloidogyne hapla showed there were interactive differences between bacterial populations and nematode species. Infected females of M. incognita produced a few progeny which were used to establish two nematode lines from single infective juveniles encumbered with either three or 26 endospores. Single juvenile descent lines of each nematode species were produced to test whether cuticle variation was greater within M. hapla lines that reproduce by facultative meiotic parthenogenesis than within lines of M. incognita, which reproduces by obligate parthenogenesis. Assays revealed variability between broods of individual females derived from single second-stage juvenile descent lines of both M. incognita and M. hapla suggesting that progeny derived from a single individual can differ in spore adhesion in both sexual and asexual nematode species. These results suggest that special mechanisms that produced these functional differences in the cuticle surface may have evolved in both sexually and asexually reproducing nematodes as a strategy to circumvent infection by this specialised hyperparasite.

  11. The identification of a gene (Cwp1), silenced during Solanum evolution, which causes cuticle microfissuring and dehydration when expressed in tomato fruit.

    Science.gov (United States)

    Hovav, Ran; Chehanovsky, Noam; Moy, Michal; Jetter, Reinhard; Schaffer, Arthur A

    2007-11-01

    One of the most intriguing phenomena of fleshy fruit is the ability to maintain high water content at maturity, even following harvest. This is accomplished by a fruit cuticle that is highly impermeable to water diffusion. In this paper, we report on a novel genotype of tomato, developed via introgression from the wild species Solanum habrochaites, which is characterized by microfissuring of the fruit cuticle and dehydration of the mature fruit. The microfissure/dehydration phenotype is inherited as a single gene, termed Cwp1 (cuticular water permeability). The gene was fine mapped, and its identity was determined by map-based cloning and differential expression analysis in near-isogenic lines. Causality of the Cwp1 gene was shown by the heterologous transgenic expression of the gene in the cultivated tomato, which caused a microfissured fruit cuticle leading to dehydrated fruit. Cwp1 encodes for a protein of unidentified function in the DUF833 domain family. The gene is expressed in the fruit epidermis of the dehydrating genotype harbouring the wild-species introgression, but not in the cultivated tomato. It is expressed only in the primitive green-fruited wild tomato species, but is not expressed in the cultivated Solanum lycopersicum and the closely related Solanum cheesmaniae and Solanum pimpinellifolium, indicating a pre-adaptive role for Cwp1 silencing in the evolution and domestication of the cultivated tomato.

  12. Two new species of the genus Streptomyces: Streptomyces camponoti sp. nov. and Streptomyces cuticulae sp. nov. isolated from the cuticle of Camponotus japonicus Mayr.

    Science.gov (United States)

    Piao, Chenyu; Zheng, Weiwei; Li, Yao; Liu, Chongxi; Jin, Liying; Song, Wei; Yan, Kai; Wang, Xiangjing; Xiang, Wensheng

    2017-09-01

    Two novel actinomycetes, designated strains 2C-SSA16(2) T and 1C-GS8 T , were isolated from the cuticle of Camponotus japonicus Mayr, collected from Northeast Agricultural University, Heilongjiang Province, north China. Both of them contained genes (involved in antibiotics biosynthesis) of the ketosynthase (KS) and methyl malonyl transferase domains (PKS-I) and the adenylation domain (NRPS). A polyphasic study was carried out to establish the taxonomic positions of these strains. The 16S rRNA gene sequence analysis showed that the two novel isolates 2C-SSA16(2) T and 1C-GS8 T exhibited 98.8% similarity with each other and that they are most closely related to Streptomyces umbrinus JCM 4521 T (99.0, 98.6%), Streptomyces ederensis JCM 4958 T (98.9, 98.7%), Streptomyces aurantiacus JCM 4453 T (98.6, 98.2%), Streptomyces glomeroaurantiacus JCM 4677 T (98.6, 98.1%), Streptomyces tauricus JCM4837 T (98.2, 98.0%) and Streptomyces phaeochromogenes JCM 4070 T (98.2, 99.2%). The corresponding phylogenetic analysis based on partial gyrB gene sequences showed that strains 2C-SSA16(2) T and 1C-GS8 T formed a cluster with the above-mentioned strains. The DNA-DNA hybridization data and phenotypic characteristics indicated that strains 2C-SSA16(2) T and 1C-GS8 T could be readily distinguished from each other and their closest phylogenetic relatives. Therefore, these two strains are suggested to represent two novel species of the genus Streptomyces, for which the names Streptomyces camponoti sp. nov. and Streptomyces cuticulae sp. nov. are proposed. The type strains are 2C-SSA16(2) T (=CGMCC 4.7276 T  = DSM 100522 T ) and 1C-GS8 T (=CGMCC 4.7348 = DSM 103127 T ), respectively.

  13. Immobilization of Aspergillus niger. beta. -D-glucosidase on aminated chitin and alumina/alginate

    Energy Technology Data Exchange (ETDEWEB)

    Bon, E.; Freire, D.; Mendes, M.F.; Soares. V.F.

    1986-01-01

    The immobilization of ..beta..-glucosidase was studied by (a) covalent coupling to aminated chitin (IME-C) and (b) adsorption onto alumina followed by gel entrapment of the suspension with calcium alginate (IME-A). The levels of catalytic activity determined against salicin at 50 C were 23.0 U/g and 0.2 U/g for the IME-C and IMA-A respectively. The first system was shown to be quite stable with a loss of only 2% of the initial activity over 14 days. The IME-A system had a half life of 14 days. The activity of IME-C was studied using cellobiose and enzymatic hydrolysates of sugar cane bagasse at several cellobiose concentrations. The activities obtained with cellobiose were 104.0 U/g and 72.0 U/g respectively. 13 references.

  14. Ancient pests: the season of the Santorini Minoan volcanic eruption and a date from insect chitin

    Science.gov (United States)

    Panagiotakopulu, Eva; Higham, Thomas; Sarpaki, Anaya; Buckland, Paul; Doumas, Christos

    2013-07-01

    Attributing a season and a date to the volcanic eruption of Santorini in the Aegean has become possible by using preserved remains of the bean weevil, Bruchus rufipes, pests of pulses, from the storage jars of the West House, in the Bronze Age settlement at Akrotiri. We have applied an improved pre-treatment methodology for dating the charred insects, and this provides a date of 1744-1538 BC. This date is within the range of others obtained from pulses from the same context and confirms the utility of chitin as a dating material. Based on the nature of the insect material and the life cycle of the species involved, we argue for a summer eruption, which took place after harvest, shortly after this material was transported into the West House storeroom.

  15. Fabrication of chitin-chitosan/nano TiO2-composite scaffolds for tissue engineering applications.

    Science.gov (United States)

    Jayakumar, R; Ramachandran, Roshni; Divyarani, V V; Chennazhi, K P; Tamura, H; Nair, S V

    2011-03-01

    In this study, we prepared chitin-chitosan/nano TiO(2) composite scaffolds using lyophilization technique for bone tissue engineering. The prepared composite scaffold was characterized using SEM, XRD, FTIR and TGA. In addition, swelling, degradation and biomineralization capability of the composite scaffolds were evaluated. The developed composite scaffold showed controlled swelling and degradation when compared to the control scaffold. Cytocompatibility of the scaffold was assessed by MTT assay and cell attachment studies using osteoblast-like cells (MG-63), fibroblast cells (L929) and human mesenchymal stem cells (hMSCs). Results indicated no sign of toxicity and cells were found attached to the pore walls within the scaffolds. These results suggested that the developed composite scaffold possess the prerequisites for tissue engineering scaffolds and it can be used for tissue engineering applications. Copyright © 2010 Elsevier B.V. All rights reserved.

  16. The prospect of using the chitin-melanin-glukancontaining materials in measures of radiating protection

    International Nuclear Information System (INIS)

    Senyuk, O.F.; Myshkovskij, N.M.; Ivchenko, V.G.; Kovalev, V.A.; Gorovoj, L.F.; Kosyakov, V.N.; Kurchenko, V.P.; Sushinskaya, N.V.; Gavrilenko, N.V.

    2004-01-01

    An installation for testing the efficiency of Petryanov fabrics in conditions of the maximal humidity is created. It was shown in research, that chitin-melanin-glukan-containing materials (ChMGM) from higher bazidial fungi has high sorptive ability in relation to isotopes of strontium, uranium, transuranic elements, in particular to americium, and also salts of heavy metals (copper, silver, lead, chromium). Main part of metal ions are quickly absorbed by these materials. The technique of processing them by ChMGM is developed with the purpose to estimate amplification the detaining ability of these filters. High concentration of salts of alkaline and alkaline-earth metals do not essentially influence the absorption level of ChMGM heavy metals and transuranic elements

  17. Effects from additives on deacetylation of chitin; Efeito de aditivos na desacetilacao de quitina

    Energy Technology Data Exchange (ETDEWEB)

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

    2001-12-01

    Deacetylation reactions of commercial chitin were carried out in aqueous sodium hydroxide solution at 115 deg C for 6 hours. The effect from additives (sodium borohydride or anthraquinone) and of bubbling inert gas (nitrogen or argon) on the characteristics of deacetylated samples were evaluated. Average degrees of acetylation and intrinsic viscosity were determined by {sup 1}H NMR spectroscopy and capillary viscometry, respectively. X-ray diffraction was employed to evaluate changes in crystallinity and infrared spectroscopy was used to monitor structural changes due to deacetylation. The bubbling of inert gas during the deacetylation reaction resulted in more crystalline samples of chitosan. Deacetylation carried out without any additive produced slightly more deacetylated chitosan but they were severely depolymerized. The depolymerization process was much less important when sodium borohydride was added to the reaction medium but the addition of anthraquinone and the bubbling of nitrogen, or argon, did not have any effect, this suggests that oxygen is not required for depolymerization. (author)

  18. 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. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Chitin based heteroatom-doped porous carbon as electrode materials for supercapacitors.

    Science.gov (United States)

    Zhou, Jie; Bao, Li; Wu, Shengji; Yang, Wei; Wang, Hui

    2017-10-01

    Chitin biomass has received much attention as an amino-functional polysaccharide precursor for synthesis of carbon materials. Rich nitrogen and oxygen dual-doped porous carbon derived from cicada slough (CS), a renewable biomass mainly composed of chitin, was synthesized and employed as electrode materials for electrochemical capacitors, for the first time ever. The cicada slough-derived carbon (CSC) was prepared by a facile process via pre-carbonization in air, followed by KOH activation. The weight ratio of KOH and char plays an important role in fabricating the microporous structure and tuning the surface chemistry of CSC. The obtained CSC had a large specific surface area (1243-2217m 2 g -1 ), fairly high oxygen content (28.95-33.78 at%) and moderate nitrogen content (1.47-4.35 at%). The electrochemical performance of the CS char and CSC as electrodes for capacitors was evaluated in a three-electrode cell configuration with 6M KOH as the electrolyte. Electrochemical studies showed that the as-prepared CSC activated at the KOH-to-char weight ratio of 2 exhibited the highest specific capacitance (266.5Fg -1 at a current density of 0.5Ag -1 ) and excellent rate capability (196.2Fg -1 remained at 20Ag -1 ) and cycle durability. In addition, the CSC-2-based symmetrical device possessed the desirable energy density and power density of about 15.97Whkg -1 and 5000Wkg -1 at 5Ag -1 , respectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Chitin stimulates expression of acidic mammalian chitinase and eotaxin-3 by human sinonasal epithelial cells in vitro.

    Science.gov (United States)

    Lalaker, Ashley; Nkrumah, Louis; Lee, Won-Kyung; Ramanathan, Murugappan; Lane, Andrew P

    2009-01-01

    Sinonasal epithelial cells participate in host defense by initiating innate immune mechanisms against potential pathogens. Antimicrobial innate mechanisms have been shown to involve Th1-like inflammatory responses. Although epithelial cells can also be induced by Th2 cytokines to express proeosinophilic mediators, no environmental agents have been identified that promote this effect. Human sinonasal epithelial cells from patients with chronic rhinosinusitis with nasal polyps (CRSwNPs) and controls were harvested and grown in primary culture. Cell cultures were exposed to a range of concentrations of chitin for 24 hours, and mRNA for acidic mammalian chitinase (AMCase), eotaxin-3, and thymic stromal-derived lymphopoietin (TSLP) were assessed. Other cultures were exposed to interleukin 4 (IL- 4) alone and in combination with dust-mite antigen (DMA) for 36 hours. Extracted mRNA and cell culture supernatant were analyzed for expression of AMCase and eotaxin-3. Chitin induced a dose-dependent expression of AMCase and eotaxin-3 mRNA but not TSLP. Patients with recalcitrant CRSwNPs showed lower baseline expression of AMCase when compared with treatment-responsive CRSwNP and less induction of AMCase expression by chitin. DMA did not directly induce expression of AMCase or eotaxin-3. Expression of eotaxin-3 was stimulated by IL-4 and further enhanced with the addition of DMA. Levels of AMCase were not significantly affected by either IL-4 or DMA exposure. In some cases, the combination of IL-4 and DMA was able to induce AMCase expression in cell cultures not producing AMCase at baseline. The abundant biopolymer chitin appears to be recognized by a yet uncharacterized receptor on sinonasal epithelial cells. Chitin stimulates production of AMCase and eotaxin-3, two pro-Th2 effector proteins. This finding suggests the existence of a novel innate immune pathway for local defense against chitin-containing organisms in the sinonasal tract. Dysregulation of this function could

  1. 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.

  2. Identification of Nanopillars on the Cuticle of the Aquatic Larvae of the Drone Fly (Diptera: Syrphidae).

    Science.gov (United States)

    Hayes, Matthew J; Levine, Timothy P; Wilson, Roger H

    2016-01-01

    Here, we describe a nano-scale surface structure on the rat-tailed maggot, the aquatic larva of the Drone fly Eristalis tenax(L.). Larvae of this syrphid hover fly live in stagnant, anaerobic water-courses that are rich in organic matter. The larvae burrow into fetid slurry and feed on microorganisms which they filter out from the organic material. This environment is rich in bacteria, fungi and algae with the capacity to form biofilms that might develop on the larval surface and harm them. Using transmission and scanning electron microscopy we have identified an array of slender (typically < 100 nm in diameter) nanopillars that cover the surface of the larvae. The high density and dimensions of these spine-like projections appear to make it difficult for bacteria to colonize the surface of the animal. This may interfere with the formation of biofilms and potentially act as a defence against bacterial infection. © The Author 2016. Published by Oxford University Press on behalf of the Entomological Society of America.

  3. Virulence and the Environment: a Novel Role for Vibrio cholerae Toxin-Coregulated Pili in Biofilm Formation on Chitin

    Science.gov (United States)

    Reguera, Gemma; Kolter, Roberto

    2005-01-01

    The toxin-coregulated pilus (TCP) of Vibrio cholerae is required for intestinal colonization and cholera toxin acquisition. Here we report that TCP mediates bacterial interactions required for biofilm differentiation on chitinaceous surfaces. We also show that undifferentiated TCP− biofilms have reduced ecological fitness and, thus, that chitin colonization may represent an ecological setting outside the host in which selection for a host colonization factor may take place. PMID:15866944

  4. CHONDROPROTECTIVE ACTIVITY OF BEE-VENOM MELITTIN AND CRAB SHELL CHITIN ON PAPAIN INDUCED OSTEOARTHRITIS IN RABBITS

    OpenAIRE

    Ravindra Babu Sajja*, Prasad K, Eswar Kumar K and G.Phani C Reddy

    2018-01-01

    In the present study the chondroprotective effect of melittin and chitin from bee venom and crab shell was examined against papain induced osteoarthritis in rabbits. The leukocyte count in synovial fluid, X-ray radiography of ankle joints and histopathology of joint cartilage were performed to assess chondroprotective activity. There is a significant fall in leukocyte count of bee venom (1.2mg/kg, s.c) treated group when compared with osteoarthritic control and the standard groups. Histopatho...

  5. Various methods for determination of the degree of N-acetylation of chitin and chitosan: a review.

    Science.gov (United States)

    Kasaai, Mohammad R

    2009-03-11

    Chitin, chitosan, and their derivatives have been identified as versatile biopolymers for a broad range of agriculture and food applications. Up to now, several methods have been developed to determine degree of N-acetylation, DA, for chitin and chitosan. In this article, an effort has been made to review the available literature information on the DA determination. These methods are classified into three categories: (1) spectroscopy (IR, (1)H NMR, (13)C NMR, (15)N NMR, and UV); (2) conventional (various types of titration, conductometry, potentiometry, ninhydrin assay, adsorption of free amino groups of chitosan by pictric acid); (3) destructive (elemental analysis, acid or enzymatic hydrolysis of chitin/chitosan and followed by the DA measurement by colorimetry or high performance liquid chromatography, pyrolysis-gas chromatography, and thermal analysis using differential scanning calorimetry) methods. These methods have been compared for their performances and limitations as well as their advantages and disadvantages. The use of IR and NMR spectroscopy methods provides a number of advantages. They do not need long-term procedures to prepare samples, and they provide information on the chemical structure. (1)H NMR and UV techniques are more sensitive than IR, (13)C NMR, and (15)N NMR spectroscopy. The IR technique is mostly used for a qualitative evaluation and comparison studies. Conventional methods are not applicable for highly acetylated chitin. The results of the latter methods are affected by ionic strength of the solvent, pH, and temperature of solution. In destructive methods, longer times are needed for the measurements compared to spectroscopy and conventional methods, but they are applicable for the entire range of the DA.

  6. Fungal-type carbohydrate binding modules from the coccolithophore Emiliania huxleyi show binding affinity to cellulose and chitin.

    Science.gov (United States)

    Rooijakkers, Bart J M; Ikonen, Martina S; Linder, Markus B

    2018-01-01

    Six fungal-type cellulose binding domains were found in the genome of the coccolithophore Emiliania huxleyi and cloned and expressed in Escherichia coli. Sequence comparison indicate high similarity to fungal cellulose binding domains, raising the question of why these domains exist in coccolithophores. The proteins were tested for binding with cellulose and chitin as ligands, which resulted in the identification of two functional carbohydrate binding modules: EHUX2 and EHUX4. Compared to benchmark fungal cellulose binding domain Cel7A-CBM1 from Trichoderma reesei, these proteins showed slightly lower binding to birch and bacterial cellulose, but were more efficient chitin binders. Finally, a set of cellulose binding domains was created based on the shuffling of one well-functioning and one non-functional domain. These were characterized in order to get more information of the binding domain's sequence-function relationship, indicating characteristic differences between the molecular basis of cellulose versus chitin recognition. As previous reports have showed the presence of cellulose in coccoliths and here we find functional cellulose binding modules, a possible connection is discussed.

  7. Fungal-type carbohydrate binding modules from the coccolithophore Emiliania huxleyi show binding affinity to cellulose and chitin.

    Directory of Open Access Journals (Sweden)

    Bart J M Rooijakkers

    Full Text Available Six fungal-type cellulose binding domains were found in the genome of the coccolithophore Emiliania huxleyi and cloned and expressed in Escherichia coli. Sequence comparison indicate high similarity to fungal cellulose binding domains, raising the question of why these domains exist in coccolithophores. The proteins were tested for binding with cellulose and chitin as ligands, which resulted in the identification of two functional carbohydrate binding modules: EHUX2 and EHUX4. Compared to benchmark fungal cellulose binding domain Cel7A-CBM1 from Trichoderma reesei, these proteins showed slightly lower binding to birch and bacterial cellulose, but were more efficient chitin binders. Finally, a set of cellulose binding domains was created based on the shuffling of one well-functioning and one non-functional domain. These were characterized in order to get more information of the binding domain's sequence-function relationship, indicating characteristic differences between the molecular basis of cellulose versus chitin recognition. As previous reports have showed the presence of cellulose in coccoliths and here we find functional cellulose binding modules, a possible connection is discussed.

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

    Directory of Open Access Journals (Sweden)

    S. Deepthi

    2014-12-01

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

  9. Effect of low shear modeled microgravity on phenotypic and central chitin metabolism in the filamentous fungi Aspergillus niger and Penicillium chrysogenum.

    Science.gov (United States)

    Sathishkumar, Yesupatham; Velmurugan, Natarajan; Lee, Hyun Mi; Rajagopal, Kalyanaraman; Im, Chan Ki; Lee, Yang Soo

    2014-08-01

    Phenotypic and genotypic changes in Aspergillus niger and Penicillium chrysogenum, spore forming filamentous fungi, with respect to central chitin metabolism were studied under low shear modeled microgravity, normal gravity and static conditions. Low shear modeled microgravity (LSMMG) response showed a similar spore germination rate with normal gravity and static conditions. Interestingly, high ratio of multiple germ tube formation of A. niger in LSMMG condition was observed. Confocal laser scanning microscopy images of calcofluor flurophore stained A. niger and P. chrysogenum showed no significant variations between different conditions tested. Transmission electron microscopy images revealed number of mitochondria increased in P. chrysogenum in low shear modeled microgravity condition but no stress related-woronin bodies in fungal hyphae were observed. To gain additional insight into the cell wall integrity under different conditions, transcription level of a key gene involved in cell wall integrity gfaA, encoding the glutamine: fructose-6-phosphate amidotransferase enzyme, was evaluated using qRT-PCR. The transcription level showed no variation among different conditions. Overall, the results collectively indicate that the LSMMG has shown no significant stress on spore germination, mycelial growth, cell wall integrity of potentially pathogenic fungi, A. niger and P. chrysogenum.

  10. Liquid Chromatography with Electrospray Ionization and Tandem Mass Spectrometry Applied in the Quantitative Analysis of Chitin-Derived Glucosamine for a Rapid Estimation of Fungal Biomass in Soil

    Directory of Open Access Journals (Sweden)

    Madelen A. Olofsson

    2016-01-01

    Full Text Available This method employs liquid chromatography-tandem mass spectrometry to rapidly quantify chitin-derived glucosamine for estimating fungal biomass. Analyte retention was achieved using hydrophilic interaction liquid chromatography, with a zwitter-ionic stationary phase (ZIC-HILIC, and isocratic elution using 60% 5 mM ammonium formate buffer (pH 3.0 and 40% ACN. Inclusion of muramic acid and its chromatographic separation from glucosamine enabled calculation of the bacterial contribution to the latter. Galactosamine, an isobaric isomer to glucosamine, found in significant amounts in soil samples, was also investigated. The two isomers form the same precursor and product ions and could not be chromatographically separated using this rapid method. Instead, glucosamine and galactosamine were distinguished mathematically, using the linear relationships describing the differences in product ion intensities for the two analytes. The m/z transitions of 180 → 72 and 180 → 84 were applied for the detection of glucosamine and galactosamine and that of 252 → 126 for muramic acid. Limits of detection were in the nanomolar range for all included analytes. The total analysis time was 6 min, providing a high sample throughput method.

  11. ATL9, a RING zinc finger protein with E3 ubiquitin ligase activity implicated in chitin- and NADPH oxidase-mediated defense responses.

    Directory of Open Access Journals (Sweden)

    Marta Berrocal-Lobo

    2010-12-01

    Full Text Available Pathogen associated molecular patterns (PAMPs are signals detected by plants that activate basal defenses. One of these PAMPs is chitin, a carbohydrate present in the cell walls of fungi and in insect exoskeletons. Previous work has shown that chitin treatment of Arabidopsis thaliana induced defense-related genes in the absence of a pathogen and that the response was independent of the salicylic acid (SA, jasmonic acid (JA and ethylene (ET signaling pathways. One of these genes is ATL9 ( = ATL2G, which encodes a RING zinc-finger like protein. In the current work we demonstrate that ATL9 has E3 ubiquitin ligase activity and is localized to the endoplasmic reticulum. The expression pattern of ATL9 is positively correlated with basal defense responses against Golovinomyces cichoracearum, a biotrophic fungal pathogen. The basal levels of expression and the induction of ATL9 by chitin, in wild type plants, depends on the activity of NADPH oxidases suggesting that chitin-mediated defense response is NADPH oxidase dependent. Although ATL9 expression is not induced by treatment with known defense hormones (SA, JA or ET, full expression in response to chitin is compromised slightly in mutants where ET- or SA-dependent signaling is suppressed. Microarray analysis of the atl9 mutant revealed candidate genes that appear to act downstream of ATL9 in chitin-mediated defenses. These results hint at the complexity of chitin-mediated signaling and the potential interplay between elicitor-mediated signaling, signaling via known defense pathways and the oxidative burst.

  12. WAFs lead molting retardation of naupliar stages with down-regulated expression profiles of chitin metabolic pathway and related genes in the copepod Tigriopus japonicus.

    Science.gov (United States)

    Hwang, Dae-Sik; Lee, Min-Chul; Kyung, Do-Hyun; Kim, Hui-Su; Han, Jeonghoon; Kim, Il-Chan; Puthumana, Jayesh; Lee, Jae-Seong

    2017-03-01

    Oil pollution is considered being disastrous to marine organisms and ecosystems. As molting is critical in the developmental process of arthropods in general and copepods, in particular, the impact will be adverse if the target of spilled oil is on molting. Thus, we investigated the harmful effects of water accommodated fractions (WAFs) of crude oil with an emphasis on inhibition of chitin metabolic pathways related genes and developmental retardation in the copepod Tigriopus japonicus. Also, we analysed the ontology and domain of chitin metabolic pathway genes and mRNA expression patterns of developmental stage-specific genes. Further, the developmental retardation followed by transcriptional modulations in nuclear receptor genes (NR) and chitin metabolic pathway-related genes were observed in the WAFs-exposed T. japonicus. As a result, the developmental time was found significantly (P<0.05) delayed in response to 40% WAFs in comparison with that of control. Moreover, the NR gene, HR3 and chitinases (CHT9 and CHT10) were up-regulated in N4-5 stages, while chitin synthase genes (CHS-1, CHS-2-1, and CHS-2-2) down-regulated in response to WAFs. In brief, a high concentration of WAFs repressed nuclear receptor genes but elicited activation of some of the transcription factors at low concentration of WAFs, resulting in suppression of chitin synthesis. Thus, we suggest that WAF can lead molting retardation of naupliar stages in T. japonicus through down-regulations of chitin metabolism. These findings will provide a better understanding of the mode of action of chitin biosynthesis associated with molting mechanism in WAF-exposed T. japonicus. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Transcriptome Comparative Profiling of Barley eibi1 Mutant Reveals Pleiotropic Effects of HvABCG31 Gene on Cuticle Biogenesis and Stress Responsive Pathways

    Directory of Open Access Journals (Sweden)

    Eviatar Nevo

    2013-10-01

    Full Text Available Wild barley eibi1 mutant with HvABCG31 gene mutation has low capacity to retain leaf water, a phenotype associated with reduced cutin deposition and a thin cuticle. To better understand how such a mutant plant survives, we performed a genome-wide gene expression analysis. The leaf transcriptomes between the near-isogenic lines eibi1 and the wild type were compared using the 22-k Barley1 Affymetrix microarray. We found that the pleiotropic effect of the single gene HvABCG31 mutation was linked to the co-regulation of metabolic processes and stress-related system. The cuticle development involved cytochrome P450 family members and fatty acid metabolism pathways were significantly up-regulated by the HvABCG31 mutation, which might be anticipated to reduce the levels of cutin monomers or wax and display conspicuous cuticle defects. The candidate genes for responses to stress were induced by eibi1 mutant through activating the jasmonate pathway. The down-regulation of co-expressed enzyme genes responsible for DNA methylation and histone deacetylation also suggested that HvABCG31 mutation may affect the epigenetic regulation for barley development. Comparison of transcriptomic profiling of barley under biotic and abiotic stresses revealed that the functions of HvABCG31 gene to high-water loss rate might be different from other osmotic stresses of gene mutations in barley. The transcriptional profiling of the HvABCG31 mutation provided candidate genes for further investigation of the physiological and developmental changes caused by the mutant.

  14. Diversity of the bacterial and fungal microflora from the midgut and cuticle of phlebotomine sand flies collected in North-Western Iran.

    Directory of Open Access Journals (Sweden)

    Mohammad Akhoundi

    Full Text Available BACKGROUND: Phlebotomine sand flies are the vectors of the leishmaniases, parasitic diseases caused by Leishmania spp. Little is known about the prevalence and diversity of sand fly microflora colonizing the midgut or the cuticle. Particularly, there is little information on the fungal diversity. This information is important for development of vector control strategies. METHODOLOGY/PRINCIPAL FINDINGS: FIVE SAND FLY SPECIES: Phlebotomus papatasi, P. sergenti, P. kandelakii, P. perfiliewi and P. halepensis were caught in Bileh Savar and Kaleybar in North-Western Iran that are located in endemic foci of visceral leishmaniasis. A total of 35 specimens were processed. Bacterial and fungal strains were identified by routine microbiological methods. We characterized 39 fungal isolates from the cuticle and/or the midgut. They belong to six different genera including Penicillium (17 isolates, Aspergillus (14, Acremonium (5, Fusarium (1, Geotrichum (1 and Candida (1. We identified 33 Gram-negative bacteria: Serratia marcescens (9 isolates, Enterobacter cloacae (6, Pseudomonas fluorescens (6, Klebsiella ozaenae (4, Acinetobacter sp. (3, Escherichia coli (3, Asaia sp. (1 and Pantoea sp. (1 as well as Gram-positive bacteria Bacillus subtilis (5 and Micrococcus luteus (5 in 10 isolates. CONCLUSION/SIGNIFICANCE: Our study provides new data on the microbiotic diversity of field-collected sand flies and for the first time, evidence of the presence of Asaia sp. in sand flies. We have also found a link between physiological stages (unfed, fresh fed, semi gravid and gravid of sand flies and number of bacteria that they carry. Interestingly Pantoea sp. and Klebsiella ozaenae have been isolated in Old World sand fly species. The presence of latter species on sand fly cuticle and in the female midgut suggests a role for this arthropod in dissemination of these pathogenic bacteria in endemic areas. Further experiments are required to clearly delineate the vectorial

  15. A Major Facilitator Superfamily protein encoded by TcMucK gene is not required for cuticle pigmentation, growth and development in Tribolium castaneum.

    Science.gov (United States)

    Mun, Seulgi; Noh, Mi Young; Osanai-Futahashi, Mizuko; Muthukrishnan, Subbaratnam; Kramer, Karl J; Arakane, Yasuyuki

    2014-06-01

    Insect cuticle pigmentation and sclerotization (tanning) are vital physiological processes for insect growth, development and survival. We have previously identified several colorless precursor molecules as well as enzymes involved in their biosynthesis and processing to yield the mature intensely colored body cuticle pigments. A recent study indicated that the Bombyx mori (silkmoth) gene, BmMucK, which encodes a protein orthologous to a Culex pipiens quiquefasciatus (Southern house mosquito) cis,cis, muconate transporter, is a member of the "Major Facilitator Superfamily" (MFS) of transporter proteins and is associated with the appearance of pigmented body segments of naturally occurring body color mutants of B. mori. While RNA interference of the BmMucK gene failed to result in any observable phenotype, RNAi using a dsRNA for an orthologous gene from the red flour beetle, Tribolium castaneum, was reported to result in molting defects and darkening of the cuticle and some body parts, leading to the suggestion that orthologs of MucK genes may differ in their functions among insects. To verify the role and essentiality of the ortholog of this gene in development and body pigmentation function in T. castaneum we obtained cDNAs for the orthologous gene (TcMucK) from RNA isolated from the GA-1 wild-type strain of T. castaneum. The sequence of a 1524 nucleotides-long cDNA for TcMucK which encodes the putatively full-length protein, was assembled from two overlapping RT-PCR fragments and the expression profile of this gene during development was analyzed by real-time PCR. This cDNA encodes a 55.8 kDa protein consisting of 507 amino acid residues and includes 11 putative transmembrane segments. Transcripts of TcMucK were detected throughout all of the developmental stages analyzed. The function of this gene was explored by injection of two different double-stranded RNAs targeting different regions of the TcMucK gene (dsTcMucKs) into young larvae to down

  16. [Basic Studies on Locoregional Injection of a Newly Designed Chitin Sol].

    Science.gov (United States)

    Chiba, Takehiro; Sugitachi, Akio; Kume, Kouhei; Segawa, Takenori; Nishinari, Yutaka; Ishida, Kaoru; Noda, Hironobu; Nishizuka, Satoshi; Kimura, Yusuke; Koeda, Keisuke; Sasaki, Akira

    2015-11-01

    Systemic chemotherapy in advanced cancer cases often provokes serious adverse events. We aimed to examine the fundamental properties and efficacy of a novel chitin sol, an anti-cancer agent with minor side effects designed to avoid the adverse effects of chemotherapy and enhance the QOL and ADL of patients. DAC-70 was used to create the novel agent termed DAC-70 sol. The anti-proliferative activity was assayed by the WST method using different types of cell lines. The anti-cancer efficacy of the novel agent was examined using cancer-bearing mice. DAC-70 sol was easily injectable through a 21-G needle. The sol suppressed proliferation of the cells in vitro. Intra-tumor injection of DAC-70 sol inhibited the rapid growth of solid tumors in the mice. CDDP-loaded DAC-70 sol, CDDP/DAC-70 sol, successfully controlled malignant ascites in the mice (psol and CDDP/DAC-70 sol is clinically useful as novel cancer chemotherapy for advanced cases. This warrants further clinical studies in cancer chemotherapy.

  17. Genetic basis of Spodoptera frugiperda (Lepidoptera: Noctuidae) resistance to the chitin synthesis inhibitor lufenuron.

    Science.gov (United States)

    do Nascimento, Antonio Rogério Bezerra; Farias, Juliano Ricardo; Bernardi, Daniel; Horikoshi, Renato Jun; Omoto, Celso

    2016-04-01

    An understanding of the genetic basis of insect resistance to insecticides is important for the establishment of insect resistance management (IRM) strategies. In this study we evaluated the inheritance pattern of resistance to the chitin synthesis inhibitor lufenuron in Spodoptera frugiperda. The LC50 values (95% CI) were 0.23 µg lufenuron mL(-1) water (ppm) (0.18-0.28) for the susceptible strain (SUS) and 210.6 µg mL(-1) (175.90-258.10) for the lufenuron-resistant strain (LUF-R), based on diet-overlay bioassay. The resistance ratio was ≈ 915-fold. The LC50 values for reciprocal crosses were 4.89 µg mL(-1) (3.79-5.97) for female LUF-R and male SUS and 5.74 µg mL(-1) (4.70-6.91) for female SUS and male LUF-R, indicating that the inheritance of S. frugiperda resistance to lufenuron is an autosomal, incompletely recessive trait. Backcrosses of the progeny of reciprocal crosses with the parental LUF-R showed a polygenic effect. The estimated minimum number of independent segregations was in the 11.02 range, indicating that resistance to lufenuron is associated with multiple genes in S. frugiperda. Based on genetic crosses, the inheritance pattern of lufenuron resistance in S. frugiperda was autosomal, incompletely recessive and polygenic. Implications of this finding to IRM are discussed in this paper. © 2015 Society of Chemical Industry.

  18. Delivery of rifampicin-chitin nanoparticles into the intracellular compartment of polymorphonuclear leukocytes.

    Science.gov (United States)

    Smitha, K T; Nisha, N; Maya, S; Biswas, Raja; Jayakumar, R

    2015-03-01

    Polymorphonuclear leukocytes (PMNs) provide the primary host defence against invading pathogens by producing reactive oxygen species (ROS) and microbicidal products. However, few pathogens can survive for a prolonged period of time within the PMNs. Additionally their intracellular lifestyle within the PMNs protect themselves from the additional lethal action of host immune systems such as antibodies and complements. Antibiotic delivery into the intracellular compartments of PMNs is a major challenge in the field of infectious diseases. In order to deliver antibiotics within the PMNs and for the better treatment of intracellular bacterial infections we synthesized rifampicin (RIF) loaded amorphous chitin nanoparticles (RIF-ACNPs) of 350±50 nm in diameter. RIF-ACNPs nanoparticles are found to be non-hemolytic and non-toxic against a variety of host cells. The release of rifampicin from the prepared nanoparticles was ∼60% in 24 h, followed by a sustained pattern till 72 h. The RIF-ACNPs nanoparticles showed 5-6 fold enhanced delivery of RIF into the intracellular compartments of PMNs. The RIF-ACNPs showed anti-microbial activity against Escherichia coli, Staphylococcus aureus and a variety of other bacteria. In summary, our results suggest that RIF-ACNPs could be used to treat a variety of intracellular bacterial infections. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Comparative anti-psoriatic efficacy studies of clobetasol loaded chitin nanogel and marketed cream.

    Science.gov (United States)

    Panonnummal, Rajitha; Jayakumar, R; Sabitha, M

    2017-01-01

    In the present study chitin nanogel loaded with anti-psoriatic drug clobetasol was developed (CLCNG) for its topical delivery in psoriasis. CLCNG had the particle size of 132±14nm, with gel like consistency, stability in refrigerator, having higher drug release properties at acidic pH. CLCNG exhibited significant toxicity towards HaCaT and THP-1cell lines by MTT assay. The uptake of nanogel by HaCaT cell lines was confirmed by fluorescent microscopy. CLCNG at 0.35mg/ml exhibited significant anti-inflammatory activity with an average of 65% and 70% inhibition in COX and LOX activities expressed in THP-1 cells. In vitro skin permeation studies revealed the increased transdermal flux with fragmented stratum corneum and loosened epidermal layers in CLCNG treated samples, compared with control drug solution. The in vivo anti-psoriatic studies done on imiquimod model confirmed the potential benefits of the nanogel for the topical delivery of clobetasol in psoriasis. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Effect of Moisture Content of Chitin-Calcium Silicate on Rate of Degradation of Cefotaxime Sodium.

    Science.gov (United States)

    Al-Nimry, Suhair S; Alkhamis, Khouloud A

    2018-04-01

    Assessment of incompatibilities between active pharmaceutical ingredient and pharmaceutical excipients is an important part of preformulation studies. The objective of the work was to assess the effect of moisture content of chitin calcium silicate of two size ranges (two specific surface areas) on the rate of degradation of cefotaxime sodium. The surface area of the excipient was determined using adsorption method. The effect of moisture content of a given size range on the stability of the drug was determined at 40°C in the solid state. The moisture content was determined at the beginning and the end of the kinetic study using TGA. The degradation in solution was studied for comparison. Increasing the moisture content of the excipient of size range 63-180 μm (surface area 7.2 m 2 /g) from 3.88 to 8.06% increased the rate of degradation of the drug more than two times (from 0.0317 to 0.0718 h -1 ). While an opposite trend was observed for the excipient of size range moisture content moisture content of 8.54%, and the degradation in solid state at both moisture contents was higher than that in solution (0.0871 h -1 ). In conclusion, the rate of degradation in solid should be studied taking into consideration the specific surface area and moisture content of the excipient at the storage condition and it may be higher than that in solution.

  1. Reinforcement of poly (vinyl alcohol films with alpha-chitin nanowhiskers

    Directory of Open Access Journals (Sweden)

    Hugo Lisboa

    2018-03-01

    Full Text Available Abstract Composites Films were produced using Poly (Vinyl Alcohol as the soft material and reinforced with Chitin Nanowhiskers(NWCH as the rigid material. The present work studies the reinforcing mechanisms of NWCH in PVA films, made through a solvent casting technique and characterized for their calorimetric, swelling and mechanical properties. DSC tests revealed a sharp increase of 45 °C in glass transition temperatures with only 1.5% NWCH, while melting temperature had a small increases suggesting an anti-plasticizing effect. Swelling tests revealed decreasing hygoscopy when NWCH volume fraction increases. Estimates for elastic tensile modulus using a model that predicts the formation of a percolating network were not consistent with the experimental data of tensile tests suggesting that contrary to the reinforcement with cellulose nanowhiskers the percolating network is not primarily responsible for the reinforcement of the films. By adjusting the Halpin-Tsai equations, modified by Nielsen it was found that the mechanical properties were mainly influenced by the packing of the NWCH.

  2. Chitin Oligosaccharide Modulates Gut Microbiota and Attenuates High-Fat-Diet-Induced Metabolic Syndrome in Mice

    Directory of Open Access Journals (Sweden)

    Junping Zheng

    2018-02-01

    Full Text Available Gut microbiota has been proved to be an indispensable link between nutrient excess and metabolic syndrome, and chitin oligosaccharide (NACOS has displayed therapeutic effects on multiple diseases such as cancer and gastritis. In this study, we aim to confirm whether NACOS can ameliorate high-fat diet (HFD-induced metabolic syndrome by rebuilding the structure of the gut microbiota community. Male C57BL/6J mice fed with HFD were treated with NACOS (1 mg/mL in drinking water for five months. The results indicate that NACOS improved glucose metabolic disorder in HFD-fed mice and suppressed mRNA expression of the protein regulators related to lipogenesis, gluconeogenesis, adipocyte differentiation, and inflammation in adipose tissues. Additionally, NACOS inhibited the destruction of the gut barrier in HFD-treated mice. Furthermore, 16S ribosome RNA sequencing of fecal samples demonstrates that NACOS promoted the growth of beneficial intestinal bacteria remarkably and decreased the abundance of inflammogenic taxa. In summary, NACOS partly rebuilt the microbial community and improved the metabolic syndrome of HFD-fed mice. These data confirm the preventive effects of NACOS on nutrient excess-related metabolic diseases.

  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. 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.

  5. Silencing the Honey Bee (Apis mellifera) Naked Cuticle Gene (nkd) Improves Host Immune Function and Reduces Nosema ceranae Infections

    Science.gov (United States)

    Li, Wenfeng; Evans, Jay D.; Huang, Qiang; Rodríguez-García, Cristina; Liu, Jie; Hamilton, Michele; Grozinger, Christina M.; Webster, Thomas C.; Su, Songkun

    2016-01-01

    ABSTRACT Nosema ceranae is a new and emerging microsporidian parasite of European honey bees, Apis mellifera, that has been implicated in colony losses worldwide. RNA interference (RNAi), a posttranscriptional gene silencing mechanism, has emerged as a potent and specific strategy for controlling infections of parasites and pathogens in honey bees. While previous studies have focused on the silencing of parasite/pathogen virulence factors, we explore here the possibility of silencing a host factor as a mechanism for reducing parasite load. Specifically, we used an RNAi strategy to reduce the expression of a honey bee gene, naked cuticle (nkd), which is a negative regulator of host immune function. Our studies found that nkd mRNA levels in adult bees were upregulated by N. ceranae infection (and thus, the parasite may use this mechanism to suppress host immune function) and that ingestion of double-stranded RNA (dsRNA) specific to nkd efficiently silenced its expression. Furthermore, we found that RNAi-mediated knockdown of nkd transcripts in Nosema-infected bees resulted in upregulation of the expression of several immune genes (Abaecin, Apidaecin, Defensin-1, and PGRP-S2), reduction of Nosema spore loads, and extension of honey bee life span. The results of our studies clearly indicate that silencing the host nkd gene can activate honey bee immune responses, suppress the reproduction of N. ceranae, and improve the overall health of honey bees. This study represents a novel host-derived therapeutic for honey bee disease treatment that merits further exploration. IMPORTANCE Given the critical role of honey bees in the pollination of agricultural crops, it is urgent to develop strategies to prevent the colony decline induced by the infection of parasites/pathogens. Targeting parasites and pathogens directly by RNAi has been proven to be useful for controlling infections in honey bees, but little is known about the disease impacts of RNAi silencing of host factors

  6. Silencing the Honey Bee (Apis mellifera) Naked Cuticle Gene (nkd) Improves Host Immune Function and Reduces Nosema ceranae Infections.

    Science.gov (United States)

    Li, Wenfeng; Evans, Jay D; Huang, Qiang; Rodríguez-García, Cristina; Liu, Jie; Hamilton, Michele; Grozinger, Christina M; Webster, Thomas C; Su, Songkun; Chen, Yan Ping

    2016-11-15

    Nosema ceranae is a new and emerging microsporidian parasite of European honey bees, Apis mellifera, that has been implicated in colony losses worldwide. RNA interference (RNAi), a posttranscriptional gene silencing mechanism, has emerged as a potent and specific strategy for controlling infections of parasites and pathogens in honey bees. While previous studies have focused on the silencing of parasite/pathogen virulence factors, we explore here the possibility of silencing a host factor as a mechanism for reducing parasite load. Specifically, we used an RNAi strategy to reduce the expression of a honey bee gene, naked cuticle (nkd), which is a negative regulator of host immune function. Our studies found that nkd mRNA levels in adult bees were upregulated by N. ceranae infection (and thus, the parasite may use this mechanism to suppress host immune function) and that ingestion of double-stranded RNA (dsRNA) specific to nkd efficiently silenced its expression. Furthermore, we found that RNAi-mediated knockdown of nkd transcripts in Nosema-infected bees resulted in upregulation of the expression of several immune genes (Abaecin, Apidaecin, Defensin-1, and PGRP-S2), reduction of Nosema spore loads, and extension of honey bee life span. The results of our studies clearly indicate that silencing the host nkd gene can activate honey bee immune responses, suppress the reproduction of N. ceranae, and improve the overall health of honey bees. This study represents a novel host-derived therapeutic for honey bee disease treatment that merits further exploration. Given the critical role of honey bees in the pollination of agricultural crops, it is urgent to develop strategies to prevent the colony decline induced by the infection of parasites/pathogens. Targeting parasites and pathogens directly by RNAi has been proven to be useful for controlling infections in honey bees, but little is known about the disease impacts of RNAi silencing of host factors. Here, we demonstrate

  7. Injectable Shear-Thinning CaSO4/FGF-18-Incorporated Chitin-PLGA Hydrogel Enhances Bone Regeneration in Mice Cranial Bone Defect Model.

    Science.gov (United States)

    Sivashanmugam, A; Charoenlarp, Pornkawee; Deepthi, S; Rajendran, Arunkumar; Nair, Shantikumar V; Iseki, Sachiko; Jayakumar, R

    2017-12-13

    For craniofacial bone regeneration, shear-thinning injectable hydrogels are favored over conventional scaffolds because of their improved defect margin adaptability, easier handling, and ability to be injected manually into deeper tissues. The most accepted method, after autografting, is the use of recombinant human bone morphogenetic protein-2 (BMP-2); however, complications such as interindividual variations, edema, and poor cost-efficiency in supraphysiological doses have been reported. The endogenous synthesis of BMP-2 is desirable, and a molecule which induces this is fibroblast growth factor-18 (FGF-18) because it can upregulate the BMP-2 expression  by supressing noggin. We developed a chitin-poly(lactide-co-glycolide) (PLGA) composite hydrogel by regeneration chemistry and then incorporated CaSO 4 and FGF-18 for this purpose. Rheologically, a 7-fold increase in the elastic modulus was observed in the CaSO 4 -incorporated chitin-PLGA hydrogels as compared to the chitin-PLGA hydrogel. Shear-thinning Herschel-Bulkley fluid nature was observed for both hydrogels. Chitin-PLGA/CaSO 4 gel showed sustained release of FGF-18. In vitro osteogenic differentiation showed an enhanced alkaline phosphatase (ALP) expression in the FGF-18-containing chitin-PLGA/CaSO 4 gel when compared to cells alone. Further, it was confirmed by studying the expression of osteogenic genes [RUNX2, ALP, BMP-2, osteocalcin (OCN), and osteopontin (OPN)], immunofluorescence staining of BMP-2, OCN, and OPN, and alizarin red S staining. Incorporation of FGF-18 in the hydrogel increased the endothelial cell migration. Further, the regeneration potential of the prepared hydrogels was tested in vivo, and longitudinal live animal μ-CT was performed. FGF-18-loaded chitin-PLGA/CaSO 4 showed early and almost complete bone healing in comparison with chitin-PLGA/CaSO 4 , chitin-PLGA/FGF-18, chitin-PLGA, and sham control systems, as confirmed by hematoxylin and eosin and osteoid tetrachrome stainings

  8. Emerging Biomedical Applications of Nano-Chitins and Nano-Chitosans Obtained via Advanced Eco-Friendly Technologies from Marine Resources

    Science.gov (United States)

    Muzzarelli, Riccardo A. A.; El Mehtedi, Mohamad; Mattioli-Belmonte, Monica

    2014-01-01

    The present review article is intended to direct attention to the technological advances made in the 2010–2014 quinquennium for the isolation and manufacture of nanofibrillar chitin and chitosan. Otherwise called nanocrystals or whiskers, n-chitin and n-chitosan are obtained either by mechanical chitin disassembly and fibrillation optionally assisted by sonication, or by e-spinning of solutions of polysaccharides often accompanied by poly(ethylene oxide) or poly(caprolactone). The biomedical areas where n-chitin may find applications include hemostasis and wound healing, regeneration of tissues such as joints and bones, cell culture, antimicrobial agents, and dermal protection. The biomedical applications of n-chitosan include epithelial tissue regeneration, bone and dental tissue regeneration, as well as protection against bacteria, fungi and viruses. It has been found that the nano size enhances the performances of chitins and chitosans in all cases considered, with no exceptions. Biotechnological approaches will boost the applications of the said safe, eco-friendly and benign nanomaterials not only in these fields, but also for biosensors and in targeted drug delivery areas. PMID:25415349

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

    Directory of Open Access Journals (Sweden)

    Deuxianto Hendarsyah3

    2006-04-01

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

  10. 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.

  11. The effect of irradiation dose and storage time on the ESR signal in the cuticle of different components of the exoskeleton of Norway lobster (Nephrops norvegicus)

    Energy Technology Data Exchange (ETDEWEB)

    Stewart, E.M. (Queen' s Univ., Belfast, Northern Ireland (United Kingdom)); Stevenson, M.H. (Department of Agriculture for Northern Ireland (United Kingdom). Food and Agricultural Chemistry Research Div. Queen' s Univ., Belfast, Northern Ireland (United Kingdom)); Gray, R. (Department for Agriculture for Northern Ireland (United Kingdom). Food and Agricultural Chemistry Research Div.)

    This paper examines the potential of ESR spectroscopy too determine if Norway lobsters have been irradiated. Ninety samples, each containing 3 whole Norway lobsters, were prepared, thirty were used as controls while the remaining sixty were given irradiation doses of approximately either 1 or 3 kGy. Following irradiation the samples were stored at 1[sup o]C for 0, 7, 14, 21 or 28 d. After each storage period the cuticle of the tail, carapace, claws and walking legs was removed, freeze-dried and ground prior to analysis using ESR spectroscopy. The control spectra were subtracted from their respective irradiated spectra thereby leaving the radiation-induced signal. Peak heights of the signals were measured. The ESR signals derived from the different components of the exoskeleton were similar in shape and varied only in their intensities. The claw samples gave the most intense signal while that from the walking legs was the weakest. There was a significant decay in the signal intensity over the storage period with the signal derived from cuticle of the claws showing the greatest diminution (44%) and that of the tail the least (17%). The signal intensities of the walking legs and carapace decreased by 22% and 30% respectively. In conclusion ESR spectroscopy is a useful technique for the qualitative detection of irradiated Norway lobster and shows considerable potential for quantification of dose received. (author).

  12. The effect of irradiation dose and storage time on the ESR signal in the cuticle of different components of the exoskeleton of Norway lobster (Nephrops norvegicus)

    International Nuclear Information System (INIS)

    Stewart, E.M.; Stevenson, M.H.; Gray, R.

    1993-01-01

    This paper examines the potential of ESR spectroscopy too determine if Norway lobsters have been irradiated. Ninety samples, each containing 3 whole Norway lobsters, were prepared, thirty were used as controls while the remaining sixty were given irradiation doses of approximately either 1 or 3 kGy. Following irradiation the samples were stored at 1 o C for 0, 7, 14, 21 or 28 d. After each storage period the cuticle of the tail, carapace, claws and walking legs was removed, freeze-dried and ground prior to analysis using ESR spectroscopy. The control spectra were subtracted from their respective irradiated spectra thereby leaving the radiation-induced signal. Peak heights of the signals were measured. The ESR signals derived from the different components of the exoskeleton were similar in shape and varied only in their intensities. The claw samples gave the most intense signal while that from the walking legs was the weakest. There was a significant decay in the signal intensity over the storage period with the signal derived from cuticle of the claws showing the greatest diminution (44%) and that of the tail the least (17%). The signal intensities of the walking legs and carapace decreased by 22% and 30% respectively. In conclusion ESR spectroscopy is a useful technique for the qualitative detection of irradiated Norway lobster and shows considerable potential for quantification of dose received. (author)

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

    International Nuclear Information System (INIS)

    Singh, Durgeshwer; Singh, Rita

    2012-01-01

    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 (p 2 /24 h at 24 h. Gamma irradiation at 25 kGy was found suitable for sterilization of the dressings. Infrared (IR) spectral scanning has shown that papain was stable on gamma irradiation at 25–35 kGy. The irradiated chitin–papain membranes were impermeable to different bacterial strains and also exhibited strong bactericidal action against both Gram-positive and Gram-negative bacteria. The fluid handling characteristics and the antimicrobial properties of chitin–papain membranes sterilized by gamma radiation were found suitable for use as wound dressing with debriding activity. - Highlight: ► Use of gamma radiation for sterilization of papain wound dressing was studied. ► Fluid handling and antimicrobial properties of irradiated dressings was evaluated. ► Gamma irradiation at 25 kGy was found suitable for sterilization of the dressings.

  14. The effect of rumen ciliates on chitinolytic activity, chitin content and the number of fungal zoospores in the rumen fluid of sheep.

    Science.gov (United States)

    Miltko, Renata; Bełżecki, Grzegorz; Herman, Andrzej; Kowalik, Barbara; Skomiał, Jacek

    2016-12-01

    The objective of this study was to investigate the effect of selected protozoa on the degradation and concentration of chitin and the numbers of fungal zoospores in the rumen fluid of sheep. Three adult ewes were fed a hay-concentrate diet, defaunated, then monofaunated with Entodinium caudatum or Diploplastron affine alone and refaunated with natural rumen fauna. The average density of the protozoa population varied from 6.1 · 10(4) (D. affine) to 42.2 · 10(4) cells/ml rumen fluid (natural rumen fauna). The inoculation of protozoa in the rumen of defaunated sheep increased the total activity of chitinolytic enzymes from 2.9 to 3.6 μmol N-acetylglucosamine/g dry matter (DM) of rumen fluid per min, the chitin concentration from 6.3 to 7.2 mg/g DM of rumen fluid and the number of fungal zoospores from 8.1 to 10.9 · 10(5) cells/ml rumen fluid. All examined indices showed diurnal variations. Ciliate population density was highest immediately prior to feeding and lowest at 4 h thereafter. The opposite effects were observed for the numbers of fungal zoospores, the chitin concentration and chitinolytic activity. Furthermore, it was found that chitin from zoospores may account for up to 95% of total microbial chitin in the rumen fluid of sheep. In summary, the examined ciliate species showed the ability of chitin degradation as well as a positive influence on the development of the ruminal fungal population.

  15. Slow Off-rates and Strong Product Binding Are Required for Processivity and Efficient Degradation of Recalcitrant Chitin by Family 18 Chitinases.

    Science.gov (United States)

    Kurašin, Mihhail; Kuusk, Silja; Kuusk, Piret; Sørlie, Morten; Väljamäe, Priit

    2015-11-27

    Processive glycoside hydrolases are the key components of enzymatic machineries that decompose recalcitrant polysaccharides, such as chitin and cellulose. The intrinsic processivity (P(Intr)) of cellulases has been shown to be governed by the rate constant of dissociation from polymer chain (koff). However, the reported koff values of cellulases are strongly dependent on the method used for their measurement. Here, we developed a new method for determining koff, based on measuring the exchange rate of the enzyme between a non-labeled and a (14)C-labeled polymeric substrate. The method was applied to the study of the processive chitinase ChiA from Serratia marcescens. In parallel, ChiA variants with weaker binding of the N-acetylglucosamine unit either in substrate-binding site -3 (ChiA-W167A) or the product-binding site +1 (ChiA-W275A) were studied. Both ChiA variants showed increased off-rates and lower apparent processivity on α-chitin. The rate of the production of insoluble reducing groups on the reduced α-chitin was an order of magnitude higher than koff, suggesting that the enzyme can initiate several processive runs without leaving the substrate. On crystalline chitin, the general activity of the wild type enzyme was higher, and the difference was magnifying with hydrolysis time. On amorphous chitin, the variants clearly outperformed the wild type. A model is proposed whereby strong interactions with polymer in the substrate-binding sites (low off-rates) and strong binding of the product in the product-binding sites (high pushing potential) are required for the removal of obstacles, like disintegration of chitin microfibrils. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  16. Structural basis for new pattern of conserved amino acid residues related to chitin-binding in the antifungal peptide from the coconut rhinoceros beetle Oryctes rhinoceros.

    Science.gov (United States)

    Hemmi, Hikaru; Ishibashi, Jun; Tomie, Tetsuya; Yamakawa, Minoru

    2003-06-20

    Scarabaecin isolated from hemolymph of the coconut rhinoceros beetle Oryctes rhinoceros is a 36-residue polypeptide that has antifungal activity. The solution structure of scarabaecin has been determined from twodimensional 1H NMR spectroscopic data and hybrid distance geometry-simulated annealing protocol calculation. Based on 492 interproton and 10 hydrogen-bonding distance restraints and 36 dihedral angle restraints, we obtained 20 structures. The average backbone root-mean-square deviation for residues 4-35 is 0.728 +/- 0.217 A from the mean structure. The solution structure consists of a two-stranded antiparallel beta-sheet connected by a type-I beta-turn after a short helical turn. All secondary structures and a conserved disulfide bond are located in the C-terminal half of the peptide, residues 18-36. Overall folding is stabilized by a combination of a disulfide bond, seven hydrogen bonds, and numerous hydrophobic interactions. The structural motif of the C-terminal half shares a significant tertiary structural similarity with chitin-binding domains of plant and invertebrate chitin-binding proteins, even though scarabaecin has no overall sequence similarity to other peptide/polypeptides including chitin-binding proteins. The length of its primary structure, the number of disulfide bonds, and the pattern of conserved functional residues binding to chitin in scarabaecin differ from those of chitin-binding proteins in other invertebrates and plants, suggesting that scarabaecin does not share a common ancestor with them. These results are thought to provide further strong experimental evidence to the hypothesis that chitin-binding proteins of invertebrates and plants are correlated by a convergent evolution process.

  17. Conservação de tangerina cv. Clemenules utilizando diferentes recobrimentos = Conservation of Mandarins cv. Clemenules with different cuticles

    Directory of Open Access Journals (Sweden)

    Rosa de Oliveira Treptow

    2007-01-01

    Full Text Available O objetivo deste trabalho foi verificar os efeitos de diferentes recobrimentos e períodos de armazenamento na conservação de tangerinas Clemenules. Após a colheita, as frutas foram submetidas ao pré-resfriamento por 12 horas a 5ºC e em seguida, aos seguintes tratamentos: T1 testemunha; T2 filme de polietileno microperfurado; T3 filme de polietileno não perfurado; T4 cera de carnaúba a 50%, diluída em água; T5 cera de carnaúba a 100% (não diluída. As tangerinas foram armazenadas por 20, 40 e 60 dias em temperatura de 5ºC e UR de 90-95%, depois foram mantidas em temperatura de 15±1ºC e UR de 75-80%, durante quatro dias simulando a comercialização. Na colheita e após cada período de armazenamento, seguido de simulação decomercialização, foram avaliadas as variáveis: perda de massa; cor; sólidos solúveis (SS; acidez titulável (AT; relação SS/AT; podridões, distúrbios fisiológicos e características sensoriais. Amodificação da atmosfera reduziu a perda de massa, a incidência de distúrbios e podridões de tangerinas Clemenules durante o armazenamento. As frutas acondicionadas em filme de polietilenosem perfuração ou aquelas revestidas com cera sem diluição apresentaram sabor estranho e menor qualidade geral. Tangerinas ‘Clemenules’ acondicionadas em filme de polietileno microperfurado ecera diluída em 50% de água podem ser armazenadas durante 60 dias a 5ºC e comercializadas durante quatro dias a 15±1ºC sem comprometer a qualidade sensorial.The aim of this work was to evaluate the effects of different cuticles and storage periods on the conservation of mandarins cv. Clemenules. After harvest the fruits were kept at 5ºC during 12 hours. Then, they were submitted to the following treatments: T1 control; T2 micro perforated polyethylene bag; T3 non-perforated polyethylene bag; T4 carnauba wax at 50% in water; T5 carnauba wax at 100% (without dilution. The mandarins were stored for 20, 40 and 60 days at 5

  18. Aspergillus fumigatus Trehalose-Regulatory Subunit Homolog Moonlights To Mediate Cell Wall Homeostasis through Modulation of Chitin Synthase Activity

    Directory of Open Access Journals (Sweden)

    Arsa Thammahong

    2017-04-01

    Full Text Available Trehalose biosynthesis is found in fungi but not humans. Proteins involved in trehalose biosynthesis are essential for fungal pathogen virulence in humans and plants through multiple mechanisms. Loss of canonical trehalose biosynthesis genes in the human pathogen Aspergillus fumigatus significantly alters cell wall structure and integrity, though the mechanistic link between these virulence-associated pathways remains enigmatic. Here we characterize genes, called tslA and tslB, which encode proteins that contain domains similar to those corresponding to trehalose-6-phosphate phosphatase but lack critical catalytic residues for phosphatase activity. Loss of tslA reduces trehalose content in both conidia and mycelia, impairs cell wall integrity, and significantly alters cell wall structure. To gain mechanistic insights into the role that TslA plays in cell wall homeostasis, immunoprecipitation assays coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS were used to reveal a direct interaction between TslA and CsmA, a type V chitin synthase enzyme. TslA regulates not only chitin synthase activity but also CsmA sub-cellular localization. Loss of TslA impacts the immunopathogenesis of murine invasive pulmonary aspergillosis through altering cytokine production and immune cell recruitment. In conclusion, our data provide a novel model whereby proteins in the trehalose pathway play a direct role in fungal cell wall homeostasis and consequently impact fungus-host interactions.

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

    Directory of Open Access Journals (Sweden)

    M.G. Souza

    2007-05-01

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

  20. Appropriate Usage Level of Shrimp Waste Meal as Chitin Source for Feeding Young Crayfish (Astacus leptodactylus Esch. 1823

    Directory of Open Access Journals (Sweden)

    Seval Bahadır Koca*, Nalan Ozgur Yigit, Arife Dulluc, Gonca Erol1, Nihal Cılbız1 and Ramazan Kucukkara1

    2011-06-01

    Full Text Available This study was conducted to determine effects of shrimp waste meal as natural chitin source at different rates (0 (control, 10, 20, 30 and 40% on growth, feed conversion ratio (FCR, survival of young crayfish (1.61±0.04 g and 3.74±0.03 cm for 60 days. Fifteen glass aquariums (70x30x40 cm were used in the experiment and 20 individuals were stocked per aquarium (95/m2. The highest of final weight and weight gain were obtained in feed with 10% shrimp waste meal group (3.29±0.23 and 1.66±0.23 g, while the lowest of final weight and weight gain was obtained in fed with 40% shrimp waste meal group (2.75±0.35 and 1.18±0.37 g, respectively. However, non-significant differences were found between final weight, weight gain, specific growth rate, final total length, feed conversion ratio, survival percentage among groups at the end of experimental period. It was concluded that shrimp waste meal as natural chitin source can be used in young crayfish diets up to 40% without adverse effect influence on growth.

  1. Evaluación analítica de óvulos de quitina Analytical evaluation of chitin pessaries

    Directory of Open Access Journals (Sweden)

    Yania Suárez Pérez

    2008-12-01

    Full Text Available Los óvulos de quitina constituyen nuevos productos en fase de investigación. Para la evaluación analítica de estos, se desarrolló un método gravimétrico directo para supositorios vaginales de diferente dosificación. La técnica se basa en la separación de la quitina de los demás componentes de la formulación según sus diferencias de solubilidad, con el empleo de la filtración al vacío. El método se validó para control de calidad, y se obtuvieron resultados satisfactorios en los parámetros evaluados: linealidad, precisión, exactitud y selectividad.Chitin pessaries are new products under research. For their analytical evaluation, a direct gravimetric method for vaginal suppositories of various dosing was designed. This technique was based on separation of chitin from the rest of the formulation components according to their solubility characteristics, by using vacuum filtering. The method was validated for quality control and the results were satisfactory in terms of the evaluated parameters such as linearity, precision, accuracy and selectivity.

  2. Domain wise docking analyses of the modular chitin binding protein CBP50 from Bacillus thuringiensis serovar konkukian S4.

    Science.gov (United States)

    Sehar, Ujala; Mehmood, Muhammad Aamer; Hussain, Khadim; Nawaz, Salman; Nadeem, Shahid; Siddique, Muhammad Hussnain; Nadeem, Habibullah; Gull, Munazza; Ahmad, Niaz; Sohail, Iqra; Gill, Saba Shahid; Majeed, Summera

    2013-01-01

    This paper presents an in silico characterization of the chitin binding protein CBP50 from B. thuringiensis serovar konkukian S4 through homology modeling and molecular docking. The CBP50 has shown a modular structure containing an N-terminal CBM33 domain, two consecutive fibronectin-III (Fn-III) like domains and a C-terminal CBM5 domain. The protein presented a unique modular structure which could not be modeled using ordinary procedures. So, domain wise modeling using MODELLER and docking analyses using Autodock Vina were performed. The best conformation for each domain was selected using standard procedure. It was revealed that four amino acid residues Glu-71, Ser-74, Glu-76 and Gln-90 from N-terminal domain are involved in protein-substrate interaction. Similarly, amino acid residues Trp-20, Asn-21, Ser-23 and Val-30 of Fn-III like domains and Glu-15, Ala-17, Ser-18 and Leu-35 of C-terminal domain were involved in substrate binding. Site-directed mutagenesis of these proposed amino acid residues in future will elucidate the key amino acids involved in chitin binding activity of CBP50 protein.

  3. 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.

  4. Hepatocyte Aggregate Formation on Chitin-Based Anisotropic Microstructures of Butterfly Wings

    Directory of Open Access Journals (Sweden)

    Abdelrahman Elbaz

    2018-01-01

    Full Text Available Scaffold nanotopography plays the most significant role in the mimicry of the in vivo microenvironment of the hepatocytes. Several attempts have been made to develop methods and substrates suited to growing hepatocytes into aggregates. Functional biomaterials, particularly biodegradable polymers, have been used in several studies aimed to develop improved scaffolds with ordered geometry and nanofibrous architecture for tissue engineering. However, there are still some limitation in their fabrication: it is not cost-efficient, is time-consuming, and exhibits some technological complications. The synthetic scaffolds are usually non-biodegradable and can be non-biocompatible compared to the naturally derived biomaterials. Here, we utilized a simple, cost-effective, and green method with two-step chemical treatment to get more selected hydrophilic butterfly wings from Morpho menelaus, Papilio ulysses telegonus, and Ornithoptera croesus lydius as a chitin-based natural scaffolds to growing hepatocyte aggregates. We established a three-dimensional (3D in vitro model for culture of HepG2 cells and aggregate formation that maintained the hepatocytes function on these natural anisotropic microstructures. Cells cultured on these substrates show higher viability than those cultured on a two-dimensional (2D culture plate. Methylthiazolyldiphenyl-tetrazolium bromide (MTT assay results revealed excellent viability of HepG2 cells on P. u. telegonus wings (fibrous area. The results also demonstrated appropriate cell activity, cell retention, and stable and functional expression in terms of albumin secretion and urea synthesis activity compared to the 2D monolayer culture of hepatocytes on the culture dish surface. With a slightly different degree, the other substrates also shown similar results. We anticipate that these natural anisotropic, biodegradable, and biocompatible substrates can maintain long-term hepatic culture as an in vitro 3D model for potential

  5. Species-specific chitin-binding module 18 expansion in the amphibian pathogen Batrachochytrium dendrobatidis.

    Science.gov (United States)

    Abramyan, John; Stajich, Jason E

    2012-01-01

    Batrachochytrium dendrobatidis is the causative agent of chytridiomycosis, which is considered one of the driving forces behind the worldwide decline in populations of amphibians. As a member of the phylum Chytridiomycota, B. dendrobatidis has diverged significantly to emerge as the only pathogen of adult vertebrates. Such shifts in lifestyle are generally accompanied by various degrees of genomic modifications, yet neither its mode of pathogenicity nor any factors associated with it have ever been identified. Presented here is the identification and characterization of a unique expansion of the carbohydrate-binding module family 18 (CBM18), specific to B. dendrobatidis. CBM (chitin-binding module) expansions have been likened to the evolution of pathogenicity in a variety of fungus species, making this expanded group a prime candidate for the identification of potential pathogenicity factors. Furthermore, the CBM18 expansions are confined to three categories of genes, each having been previously implicated in host-pathogen interactions. These correlations highlight this specific domain expansion as a potential key player in the mode of pathogenicity in this unique fungus. The expansion of CBM18 in B. dendrobatidis is exceptional in its size and diversity compared to other pathogenic species of fungi, making this genomic feature unique in an evolutionary context as well as in pathogenicity. Amphibian populations are declining worldwide at an unprecedented rate. Although various factors are thought to contribute to this phenomenon, chytridiomycosis has been identified as one of the leading causes. This deadly fungal disease is cause by Batrachochytrium dendrobatidis, a chytrid fungus species unique in its pathogenicity and, furthermore, its specificity to amphibians. Despite more than two decades of research, the biology of this fungus species and its deadly interaction with amphibians had been notoriously difficult to unravel. Due to the alarming rate of worldwide

  6. Transcriptomic analysis of two Beauveria bassiana strains grown on cuticle extracts of the silkworm uncovers their different metabolic response at early infection stage.

    Science.gov (United States)

    Wang, Jing-Jie; Bai, Wen-Wen; Zhou, Wei; Liu, Jing; Chen, Jie; Liu, Xiao-Yuan; Xiang, Ting-Ting; Liu, Ren-Hua; Wang, Wen-Hui; Zhang, Bao-Ling; Wan, Yong-Ji

    2017-05-01

    Beauveria bassiana is an important entomopathogenic fungus which not only widely distributes in the environment but also shows phenotypic diversity. However, the mechanism of pathogenic differences among natural B. bassiana strains has not been revealed at transcriptome-wide level. In the present study, in order to explore the mechanism, two B. bassiana strains with different pathogenicity were isolated from silkworms (Bombyx mori L.) and selected to analyze the gene expression of early stage by culturing on cuticle extracts of the silkworm and using RNA-sequencing technique. A total of 2108 up-regulated and 1115 down-regulated genes were identified in B. bassiana strain GXsk1011 (hyper-virulent strain) compared with B. bassiana strain GXtr1009 (hypo-virulent strain), respectively. The function categorization of differential expressed genes (DEGs) showed that most of them involved in metabolic process, biosynthesis of secondary metabolites, catalytic activity, and some involved in nutrition uptake, adhesion and host defense were also noted. Based on our data, distinct pathogenicity among different strains of B. bassiana may largely attribute to unique gene expression pattern which differed at very early infection process. Most of the genes involved in conidia adhesion, cuticle degradation and fungal growth were up-regulated in hyper-virulent B. bassiana strain GXsk1011. Furthermore, in combination with fungal growth analysis, our research provided a clue that fungal growth may also play an important role during early infection process. The results will help to explain why different B. bassiana strains show distinct pathogenicity on the same host even under same condition. Moreover, the transcriptome data were also useful for screening potential virulence factors. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Extracellular esterases of phylloplane yeast Pseudozyma antarctica induce defect on cuticle layer structure and water-holding ability of plant leaves.

    Science.gov (United States)

    Ueda, Hirokazu; Mitsuhara, Ichiro; Tabata, Jun; Kugimiya, Soichi; Watanabe, Takashi; Suzuki, Ken; Yoshida, Shigenobu; Kitamoto, Hiroko

    2015-08-01

    Aerial plant surface (phylloplane) is a primary key habitat for many microorganisms but is generally recognized as limited in nutrient resources. Pseudozyma antarctica, a nonpathogenic yeast, is commonly isolated from plant surfaces and characterized as an esterase producer with fatty acid assimilation ability. In order to elucidate the biological functions of these esterases, culture filtrate with high esterase activity (crude enzyme) of P. antarctica was applied onto leaves of tomato and Arabidopsis. These leaves showed a wilty phenotype, which is typically associated with water deficiency. Furthermore, we confirmed that crude enzyme-treated detached leaves clearly lost their water-holding ability. In treated leaves of both plants, genes associated to abscisic acid (ABA; a plant stress hormone responding osmotic stress) were activated and accumulation of ABA was confirmed in tomato plants. Microscopic observation of treated leaf surfaces revealed that cuticle layer covering the aerial epidermis of leaves became thinner. A gas chromatography-mass spectrometry (GC-MS) analysis exhibited that fatty acids with 16 and 18 carbon chains were released in larger amounts from treated leaf surfaces, indicating that the crude enzyme has ability to degrade lipid components of cuticle layer. Among the three esterases detected in the crude enzyme, lipase A, lipase B, and P. antarctica esterase (PaE), an in vitro enzyme assay using para-nitrophenyl palmitate as substrate demonstrated that PaE was the most responsible for the degradation. These results suggest that PaE has a potential role in the extraction of fatty acids from plant surfaces, making them available for the growth of phylloplane yeasts.

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

    Science.gov (United States)

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

    2008-01-01

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

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

    NARCIS (Netherlands)

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

    2015-01-01

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

  10. β-Chitin and chitosan from squid gladius: Biological activities of chitosan and its application as clarifying agent for apple juice.

    Science.gov (United States)

    Abdelmalek, Baha Eddine; Sila, Assaâd; Haddar, Anissa; Bougatef, Ali; Ayadi, Mohamed Ali

    2017-11-01

    Chitin is the second most abundant polysaccharide in biomass after cellulose and the term chitosan usually refers to a family of polymers obtained after chitin deacetylation. The aim of this work was the preparation and the characterization of chitin and chitosan from the gladius (pen) of the European squid (Loligo vulgaris). A high level of deproteinization (more than 80%) was recorded using Alcalase ® with an enzyme/protein ratio of 10U/mg. The demineralization of the gladius was completely achieved within 8h at room temperature in HCl. 13 C NMR, FTIR, and XRD diffractograms of prepared chitin and chitosan were taken and then degree of deacetylation of chitosan was calculated using 13 C CP/MAS-NMR Spectroscopic. Further, in vitro antioxidant capacity of chitosan was evaluated on 1,1-diphenyl-2-picrylhydrazyl method (IC 50 =3.2mgmL -1 ) and the β-carotene bleaching assay (IC 50 =3.3mgmL -1 ). Antimicrobial activity was also investigated and assays indicated that prepared chitosan exhibited marked inhibitory activity against all microbial strains tested. Additionally, chitosan was tested such as clarifying agent for apple juice and showed powerful clarification capability, without affecting nutritional value. Furthermore, the results suggested that prepared chitosan could be used as alternative additive in pharmaceutical preparations and food industry. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. 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.

  12. Morphological study of chitin from Xiphopenaeus kroyeri exoskeletons by using atomic force microscopy (AFM) and CPMAS {sup 13} C NMR; Estudo morfologico de quitina da exocuticula de Xiphopenaeus kroyeri por AFM e por CPMAS {sup 13} C NMR

    Energy Technology Data Exchange (ETDEWEB)

    Silva, K.M.; Tavares, M.I.; Andrade, C.T. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Inst. de Macromoleculas; Simao, R.A. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia. Programa de Engenharia Metalurgica e de Materiais

    1999-07-01

    A sample of {alpha} chitin was isolated from exoskeletons of Xiphopenaeus kroyeri. This sample ws dissolved in phosphoric acid and recovered as a fibrous precipitate. Atomic force microscopy was used in noncontact mode to obtain images of the native chitin sample. Different morphological features were observed, including rigid rod crystals 200-300 nm wide. Solid state {sup 13} C NMR techniques were used to investigate chitin samples, and revealed molecular order in both samples. The differences observed in the proton spin-lattice relaxation times in the rotating frame, T{sup H1}{sub p} were attributed to the formation of hydrogen bonds in preferential sites in the samples. (author)

  13. ADSORPTION TO CHITIN – A VIABLE AND ORGANISM-PROTECTING METHOD FOR BIOMONITORING METALS PRESENT IN DIFFERENT ENVIRONMENTAL COMPARTMENTS GETTING CONTACTED WITH ARTHROPODS

    Directory of Open Access Journals (Sweden)

    S. Fränzle

    2015-04-01

    Full Text Available Among the various biopolymers which cover outer interfaces of organisms, chitin is the most abundant: each year several billion metric tons (possibly even much more are produced by arthropods and processed in soil and litter, wet sediment  (especially in moist soils while otherwise chitin samples can persist virtually unchanged for geological periods of time. Moreover, arthropods, among which Coleoptera are represented by some 400,000 species alone, inhabit almost all ecosystems, way beyond the ecological range of, say, mosses. Given that adsorption of metalliferous analytes (ions, volatile compounds, complexes of whatever net charge to chitin obtained from arthropods can be demonstrated (and it partly was already, it is feasible to obtain data on environmental element contents in all water, soil and gas phase (atmosphere by dissolving, analyzing outermost (part of exocuticle chitin layers. Data on relative uptake contributions/environmental burdens of either compartment can be obtained by both interspecies-comparisons and sampling of different parts of some larger arthropod (abdomen-, outer- and inner wing surfaces of sizable beetles. As just a very thin chitin layer (< 2 µm is ablated from the animal´s outer surface by dissolution using little toxic components, sampling will not cause harm to them, enabling a repeated sampling of the same specimen (e.g. for taking t = 0 starting values and b use of rare or/and protected species. Applications are with both biomonitoring and a better understanding of metal ion transport in ecosystems, e.g. concerning interfacial Mn+ binding to dying zooplankton then sinking below the chemokline of euxinic water bodies. An indirect metal levels monitoring of woody plants and underneath soils also appears feasible.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-12-21

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

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

    International Nuclear Information System (INIS)

    Rogers, Robin

    2013-01-01

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

  16. (EOI) Form

    International Development Research Centre (IDRC) Digital Library (Canada)

    Dorine Odongo

    COLLABORATING TECHNICAL AGENCIES: EXPRESSION OF INTEREST FORM. • Please read the information provided about the initiative and the eligibility requirements in the Prospectus before completing this application form. • Ensure all the sections of the form are accurately completed and saved in PDF format.

  17. Modular forms

    NARCIS (Netherlands)

    Edixhoven, B.; van der Geer, G.; Moonen, B.; Edixhoven, B.; van der Geer, G.; Moonen, B.

    2008-01-01

    Modular forms are functions with an enormous amount of symmetry that play a central role in number theory, connecting it with analysis and geometry. They have played a prominent role in mathematics since the 19th century and their study continues to flourish today. Modular forms formed the

  18. Sequence and structural analysis of the chitinase insertion domain reveals two conserved motifs involved in chitin-binding.

    Directory of Open Access Journals (Sweden)

    Hai Li

    2010-01-01

    Full Text Available Chitinases are prevalent in life and are found in species including archaea, bacteria, fungi, plants, and animals. They break down chitin, which is the second most abundant carbohydrate in nature after cellulose. Hence, they are important for maintaining a balance between carbon and nitrogen trapped as insoluble chitin in biomass. Chitinases are classified into two families, 18 and 19 glycoside hydrolases. In addition to a catalytic domain, which is a triosephosphate isomerase barrel, many family 18 chitinases contain another module, i.e., chitinase insertion domain. While numerous studies focus on the biological role of the catalytic domain in chitinase activity, the function of the chitinase insertion domain is not completely understood. Bioinformatics offers an important avenue in which to facilitate understanding the role of residues within the chitinase insertion domain in chitinase function.Twenty-seven chitinase insertion domain sequences, which include four experimentally determined structures and span five kingdoms, were aligned and analyzed using a modified sequence entropy parameter. Thirty-two positions with conserved residues were identified. The role of these conserved residues was explored by conducting a structural analysis of a number of holo-enzymes. Hydrogen bonding and van der Waals calculations revealed a distinct subset of four conserved residues constituting two sequence motifs that interact with oligosaccharides. The other conserved residues may be key to the structure, folding, and stability of this domain.Sequence and structural studies of the chitinase insertion domains conducted within the framework of evolution identified four conserved residues which clearly interact with the substrates. Furthermore, evolutionary studies propose a link between the appearance of the chitinase insertion domain and the function of family 18 chitinases in the subfamily A.

  19. Evolution and functional insights of different ancestral orthologous clades of chitin synthase genes in the fungal tree of life

    Directory of Open Access Journals (Sweden)

    Mu eLi

    2016-02-01

    Full Text Available Chitin synthases (CHSs are key enzymes in the biosynthesis of chitin, an important structural component of fungal cell walls that can trigger innate immune responses in host plants and animals. Members of CHS gene family perform various functions in fungal cellular processes. Previous studies focused primarily on classifying diverse CHSs into different classes, regardless of their functional diversification, or on characterizing their functions in individual fungal species. A complete and systematic comparative analysis of CHS genes based on their orthologous relationships will be valuable for elucidating the evolution and functions of different CHS genes in fungi. Here, we identified and compared members of the CHS gene family across the fungal tree of life, including 18 divergent fungal lineages. Phylogenetic analysis revealed that the fungal CHS gene family is comprised of at least 10 ancestral orthologous clades, which have undergone multiple independent duplications and losses in different fungal lineages during evolution. Interestingly, one of these CHS clades (class III was expanded in plant or animal pathogenic fungi belonging to different fungal lineages. Two clades (classes VIb and VIc identified for the first time in this study occurred mainly in plant pathogenic fungi from Sordariomycetes and Dothideomycetes. Moreover, members of classes III and VIb were specifically up-regulated during plant infection, suggesting important roles in pathogenesis. In addition, CHS-associated networks conserved among plant pathogenic fungi are involved in various biological processes, including sexual reproduction and plant infection. We also identified specificity-determining sites, many of which are located at or adjacent to important structural and functional sites that are potentially responsible for functional divergence of different CHS classes. Overall, our results provide new insights into the evolution and function of members of CHS gene

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

    International Nuclear Information System (INIS)

    Anandhavelu, S.; Thambidurai, S.

    2013-01-01

    Highlights: ► UV absorption at 260–360 nm confirmed strong binding of ZnO with chitosan–GO sheets. ► Chitin-based GO–ZnO shows higher electrical conductivity than chitosan-based GO–ZnO. ► Chitin-based GO–ZnO will useful in sensing, catalysis and energy storage applications. -- Abstract: We synthesized two composites/hybrid composites with a graphene oxide (GO)/mixed GO–ZnO filler using either a chitin or a chitosan matrix. Fourier transform infrared spectroscopy analysis confirmed that chitin had been converted to chitosan during matrix fabrication because only chitosan, ZnO and GO were shown to be present in the composites/hybrid composites. Raman spectroscopy indicated the display of D and G bands at 1345 cm −1 and 1584 cm −1 , respectively. UV absorption peaks appeared at 260–360 nm and 201 nm in both hybrid composites, which indicate a strong binding of ZnO within the chitosan–GO sheets. High resolution scanning electron microscopy and atomic force microscopy studies demonstrated that on a molecular scale ZnO was well dispersed in the hybrid composites. Impedance spectroscopy and a four-probe resistivity method were used for room temperature electrical conductivity measurements. The electrical conductivity of the chitin-based GO–ZnO hybrid composites was estimated to be ∼5.94 × 10 6 S/cm and was greater than that of the chitosan-based GO–ZnO hybrid composite (∼4.13 × 10 6 S/cm). The chitin-based GO–ZnO hybrid composite had a higher optical band gap (3.4 eV) than the chitosan-based GO–ZnO hybrid composite (3.0 eV). The current–voltage measurement showed that electrical sheets resistance of the chitosan-based composites decreased with formation of ZnO

  1. Secondary metabolite gene clusters in the entomopathogen fungus Metarhizium anisopliae: genome identification and patterns of expression in a cuticle infection model

    Directory of Open Access Journals (Sweden)

    Nicolau Sbaraini

    2016-10-01

    Full Text Available Abstract Background The described species from the Metarhizium genus are cosmopolitan fungi that infect arthropod hosts. Interestingly, while some species infect a wide range of hosts (host-generalists, other species infect only a few arthropods (host-specialists. This singular evolutionary trait permits unique comparisons to determine how pathogens and virulence determinants emerge. Among the several virulence determinants that have been described, secondary metabolites (SMs are suggested to play essential roles during fungal infection. Despite progress in the study of pathogen-host relationships, the majority of genes related to SM production in Metarhizium spp. are uncharacterized, and little is known about their genomic organization, expression and regulation. To better understand how infection conditions may affect SM production in Metarhizium anisopliae, we have performed a deep survey and description of SM biosynthetic gene clusters (BGCs in M. anisopliae, analyzed RNA-seq data from fungi grown on cattle-tick cuticles, evaluated the differential expression of BGCs, and assessed conservation among the Metarhizium genus. Furthermore, our analysis extended to the construction of a phylogeny for the following three BGCs: a tropolone/citrinin-related compound (MaPKS1, a pseurotin-related compound (MaNRPS-PKS2, and a putative helvolic acid (MaTERP1. Results Among 73 BGCs identified in M. anisopliae, 20 % were up-regulated during initial tick cuticle infection and presumably possess virulence-related roles. These up-regulated BGCs include known clusters, such as destruxin, NG39x and ferricrocin, together with putative helvolic acid and, pseurotin and tropolone/citrinin-related compound clusters as well as uncharacterized clusters. Furthermore, several previously characterized and putative BGCs were silent or down-regulated in initial infection conditions, indicating minor participation over the course of infection. Interestingly, several up

  2. Atmospheric Carbon Dioxide and its Relation to Carbon Cycle Perturbations During Ocean Anoxic Event 1d: A High Resolution Record From Dispersed Plant Cuticle

    Science.gov (United States)

    Richey, J. D.; Upchurch, G. R.; Joeckel, R.; Smith, J. J.; Ludvigson, G. A.; Lomax, B. H.

    2013-12-01

    Past geological greenhouse intervals are associated with Ocean Anoxic Events (OAEs), which result from an increase in marine primary productivity and/or an increase in the preservation of organic matter. The end point is widespread black shale deposition combined with a long-term atmospheric positive δ13C excursion and an increase in the burial of 12C. Some OAEs show a negative δ13C excursion preceding the positive excursion, indicating a perturbation in the global carbon cycle prior to the initiation of these events. The Rose Creek (RCP) locality, southeastern Nebraska, is the only known terrestrial section that preserves OAE1d (Cretaceous, Albian-Cenomanian Boundary) and has abundant charcoal and plant cuticle. These features allow for a combined carbon isotope and stomatal index (SI) analysis to determine both changes in the cycling between carbon pools (C isotope analysis) and changes in paleo-CO2 via changes in SI. Preliminary (and ongoing) SI data analysis using dispersed cuticle of Pandemophyllum kvacekii (an extinct Laurel) collected at 30 cm intervals indicate changes in SI consistent with changes in CO2. Fitting our samples to a published RCP δ13C profile, pre-excursion CO2 concentrations are high. CO2 decreases to lower concentrations in the basal 1.2 m of the RCP section, where δ13Cbulk shows a negative excursion and δ13Ccharcoal remains at pre-excursion values. CO2 concentrations become higher toward the top of the negative δ13C excursion, where δ13Cbulk and δ13Ccharcoal are at their most negative values, and drop as the negative carbon excursion terminates. Using published transfer functions, we estimate that pre-excursion CO2 concentrations were a maximum of 900 ppm. In the basal 1.2 m of RCP, CO2 drops to a maximum of 480 ppm, and rises to a maximum of 710 ppm near the top of the negative excursion. As δ13C values rise towards pre-excursion values, CO2 declines to a maximum of 400 ppm. The trend in SI is comparable to the trend in δ13

  3. Horizontal gene transfer contributed to the evolution of extracellular surface structures: the freshwater polyp Hydra is covered by a complex fibrous cuticle containing glycosaminoglycans and proteins of the PPOD and SWT (sweet tooth families.

    Directory of Open Access Journals (Sweden)

    Angelika Böttger

    Full Text Available The single-cell layered ectoderm of the fresh water polyp Hydra fulfills the function of an epidermis by protecting the animals from the surrounding medium. Its outer surface is covered by a fibrous structure termed the cuticle layer, with similarity to the extracellular surface coats of mammalian epithelia. In this paper we have identified molecular components of the cuticle. We show that its outermost layer contains glycoproteins and glycosaminoglycans and we have identified chondroitin and chondroitin-6-sulfate chains. In a search for proteins that could be involved in organising this structure we found PPOD proteins and several members of a protein family containing only SWT (sweet tooth domains. Structural analyses indicate that PPODs consist of two tandem β-trefoil domains with similarity to carbohydrate-binding sites found in lectins. Experimental evidence confirmed that PPODs can bind sulfated glycans and are secreted into the cuticle layer from granules localized under the apical surface of the ectodermal epithelial cells. PPODs are taxon-specific proteins which appear to have entered the Hydra genome by horizontal gene transfer from bacteria. Their acquisition at the time Hydra evolved from a marine ancestor may have been critical for the transition to the freshwater environment.

  4. Preparation, characterization and environmental/electrochemical energy storage testing of low-cost biochar from natural chitin obtained via pyrolysis at mild conditions

    Science.gov (United States)

    Magnacca, Giuliana; Guerretta, Federico; Vizintin, Alen; Benzi, Paola; Valsania, Maria C.; Nisticò, Roberto

    2018-01-01

    Chitin (a biopolymer obtained from shellfish industry) was used as precursor for the production of biochars obtained via pyrolysis treatments performed at mild conditions (in the 290-540 °C range). Biochars were physicochemical characterized in order to evaluate the pyrolysis-induced effects in terms of both functional groups and material structure. Moreover, such carbonaceous materials were tested as adsorbent substrates for the removal of target molecules from aqueous environment as well as in solid-gas experiments, to measure the adsorption capacities and selectivity toward CO2. Lastly, biochars were also investigated as possible cathode materials in sustainable and low-cost electrochemical energy storage devices, such as lithium-sulphur (Li-S) batteries. Interestingly, experimental results evidenced that such chitin-derived biochars obtained via pyrolysis at mild conditions are sustainable, low-cost and easy scalable alternative materials suitable for both environmental and energetic applications.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-07-10

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

  6. Paenibacillus larvae chitin-degrading protein PlCBP49 is a key virulence factor in American Foulbrood of honey bees.

    Directory of Open Access Journals (Sweden)

    Eva Garcia-Gonzalez

    2014-07-01

    Full Text Available Paenibacillus larvae, the etiological agent of the globally occurring epizootic American Foulbrood (AFB of honey bees, causes intestinal infections in honey bee larvae which develop into systemic infections inevitably leading to larval death. Massive brood mortality might eventually lead to collapse of the entire colony. Molecular mechanisms of host-microbe interactions in this system and of differences in virulence between P. larvae genotypes are poorly understood. Recently, it was demonstrated that the degradation of the peritrophic matrix lining the midgut epithelium is a key step in pathogenesis of P. larvae infections. Here, we present the isolation and identification of PlCBP49, a modular, chitin-degrading protein of P. larvae and demonstrate that this enzyme is crucial for the degradation of the larval peritrophic matrix during infection. PlCBP49 contains a module belonging to the auxiliary activity 10 (AA10, formerly CBM33 family of lytic polysaccharide monooxygenases (LPMOs which are able to degrade recalcitrant polysaccharides. Using chitin-affinity purified PlCBP49, we provide evidence that PlCBP49 degrades chitin via a metal ion-dependent, oxidative mechanism, as already described for members of the AA10 family. Using P. larvae mutants lacking PlCBP49 expression, we analyzed in vivo biological functions of PlCBP49. In the absence of PlCBP49 expression, peritrophic matrix degradation was markedly reduced and P. larvae virulence was nearly abolished. This indicated that PlCBP49 is a key virulence factor for the species P. larvae. The identification of the functional role of PlCBP49 in AFB pathogenesis broadens our understanding of this important family of chitin-binding and -degrading proteins, especially in those bacteria that can also act as entomopathogens.

  7. Ochratoxin A removal from red wine by several oenological fining agents: bentonite, egg albumin, allergen-free adsorbents, chitin and chitosan.

    Science.gov (United States)

    Quintela, S; Villarán, M C; López De Armentia, I; Elejalde, E

    2012-01-01

    The ability of several oenological fining agents to remove ochratoxin A (OTA) from red wine was studied. The adsorbents tested were activated sodium bentonite, egg albumin, allergen-free adsorbents (complex PVPP, plant protein and amorphous silica (complex) and high molecular weight gelatine), and the non-toxic biodegradable polymers (chitin and chitosan). Several dosages within the oenological use range were tested and the wine pH, colour parameters and polyphenol concentration impact associated with each fining agent were studied. Generally, OTA removal achieved in all treatments was higher when the adsorbent dosage increased, but the impact on wine quality also was higher. Chitin at 50 g hl(-1) removed 18% the OTA without affecting significantly the wine-quality parameters. At the highest dosage tested the gelatine and complex treatments achieved greater OTA removal (up to 39-40%) compared with bentonite, egg albumin and chitin. Moreover, the gelatine and the complex had a lower impact on colour parameters and polyphenol concentration compared with chitosan, whilst OTA was reduced to around 40%. Chitosan achieved the greatest OTA removal (67%), but it strongly affected the wine-quality parameters. Otherwise, bentonite showed a relative efficiency to remove OTA, but the CI value decreased considerably. The egg albumin treatment only removed OTA up to 16% and moreover affected strongly the CI value and CIELab parameters. The results of this survey showed that the non-toxic chitin adsorbent and the allergen-free adsorbents tested could be considered as alternative fining agents to reduce OTA in red wine.

  8. A Chitin-binding Protein Purified from Moringa oleifera Seeds Presents Anticandidal Activity by Increasing Cell Membrane Permeability and Reactive Oxygen Species Production

    Directory of Open Access Journals (Sweden)

    João X.S. Neto

    2017-06-01

    Full Text Available Candida species are opportunistic pathogens that infect immunocompromised and/or immunosuppressed patients, particularly in hospital facilities, that besides representing a significant threat to health increase the risk of mortality. Apart from echinocandins and triazoles, which are well tolerated, most of the antifungal drugs used for candidiasis treatment can cause side effects and lead to the development of resistant strains. A promising alternative to the conventional treatments is the use of plant proteins. M. oleifera Lam. is a plant with valuable medicinal properties, including antimicrobial activity. This work aimed to purify a chitin-binding protein from M. oleifera seeds and to evaluate its antifungal properties against Candida species. The purified protein, named Mo-CBP2, represented about 0.2% of the total seed protein and appeared as a single band on native PAGE. By mass spectrometry, Mo-CBP2 presented 13,309 Da. However, by SDS-PAGE, Mo-CBP2 migrated as a single band with an apparent molecular mass of 23,400 Da. Tricine-SDS-PAGE of Mo-CBP2 under reduced conditions revealed two protein bands with apparent molecular masses of 7,900 and 4,600 Da. Altogether, these results suggest that Mo-CBP2 exists in different oligomeric forms. Moreover, Mo-CBP2 is a basic glycoprotein (pI 10.9 with 4.1% (m/m sugar and it did not display hemagglutinating and hemolytic activities upon rabbit and human erythrocytes. A comparative analysis of the sequence of triptic peptides from Mo-CBP2 in solution, after LC-ESI-MS/MS, revealed similarity with other M. oleifera proteins, as the 2S albumin Mo-CBP3 and flocculating proteins, and 2S albumins from different species. Mo-CBP2 possesses in vitro antifungal activity against Candida albicans, C. parapsilosis, C. krusei, and C. tropicalis, with MIC50 and MIC90 values ranging between 9.45–37.90 and 155.84–260.29 μM, respectively. In addition, Mo-CBP2 (18.90 μM increased the cell membrane permeabilization

  9. Insight into the adsorption profiles of the Saprolegnia monoica chitin synthase MIT domain on POPA and POPC membranes by molecular dynamics simulation studies.

    Science.gov (United States)

    Kuang, Guanglin; Liang, Lijun; Brown, Christian; Wang, Qi; Bulone, Vincent; Tu, Yaoquan

    2016-02-21

    The critical role of chitin synthases in oomycete hyphal tip growth has been established. A microtubule interacting and trafficking (MIT) domain was discovered in the chitin synthases of the oomycete model organism, Saprolegnia monoica. MIT domains have been identified in diverse proteins and may play a role in intracellular trafficking. The structure of the Saprolegnia monoica chitin synthase 1 (SmChs1) MIT domain has been recently determined by our group. However, although our in vitro assay identified increased strength in interactions between the MIT domain and phosphatidic acid (PA) relative to other phospholipids including phosphatidylcholine (PC), the mechanism used by the MIT domain remains unknown. In this work, the adsorption behavior of the SmChs1 MIT domain on POPA and POPC membranes was systematically investigated by molecular dynamics simulations. Our results indicate that the MIT domain can adsorb onto the tested membranes in varying orientations. Interestingly, due to the specific interactions between MIT residues and lipid molecules, the binding affinity to the POPA membrane is much higher than that to the POPC membrane. A binding hotspot, which is critical for the adsorption of the MIT domain onto the POPA membrane, was also identified. The lower binding affinity to the POPC membrane can be attributed to the self-saturated membrane surface, which is unfavorable for hydrogen-bond and electrostatic interactions. The present study provides insight into the adsorption profile of SmChs1 and additionally has the potential to improve our understanding of other proteins containing MIT domains.

  10. Three-dimensional (3D) structure prediction and function analysis of the chitin-binding domain 3 protein HD73_3189 from Bacillus thuringiensis HD73.

    Science.gov (United States)

    Zhan, Yiling; Guo, Shuyuan

    2015-01-01

    Bacillus thuringiensis (Bt) is capable of producing a chitin-binding protein believed to be functionally important to bacteria during the stationary phase of its growth cycle. In this paper, the chitin-binding domain 3 protein HD73_3189 from B. thuringiensis has been analyzed by computer technology. Primary and secondary structural analyses demonstrated that HD73_3189 is negatively charged and contains several α-helices, aperiodical coils and β-strands. Domain and motif analyses revealed that HD73_3189 contains a signal peptide, an N-terminal chitin binding 3 domains, two copies of a fibronectin-like domain 3 and a C-terminal carbohydrate binding domain classified as CBM_5_12. Moreover, analysis predicted the protein's associated localization site to be the cell wall. Ligand site prediction determined that amino acid residues GLU-312, TRP-334, ILE-341 and VAL-382 exposed on the surface of the target protein exhibit polar interactions with the substrate.

  11. Adsorption of TNT, DNAN, NTO, FOX7, and NQ onto cellulose, chitin, and cellulose triacetate. Insights from Density Functional Theory calculations

    Science.gov (United States)

    Todde, Guido; Jha, Sanjiv K.; Subramanian, Gopinath; Shukla, Manoj K.

    2018-02-01

    Insensitive munitions (IM) compounds such as DNAN (2,4-dinitroanisole), NTO (3-nitro-1,2,4-triazol-5-one), NQ (nitroguanidine), and FOX7 (1,1-diamino-2,2-dinitroethene) reduce the risk of accidental explosions due to shock and high temperature exposure. These compounds are being used as replacements for sensitive munition compounds such as TNT (2,4,6-trinitromethylbenzene) and RDX (1,3,5-hexahydro-1,3,5-trinitro-1,3,5-triazine). NTO and NQ in IM compounds are more soluble than TNT or RDX, hence they can easily spread in the environment and get dissolved if exposed to precipitation. DNAN solubility is comparable to TNT solubility. Cellulosic biomass, due to its abundance in the environment and its chemical structure, has a high probability of adsorbing these IM compounds, and thus, it is important to investigate the interactions between cellulose and cellulose like biopolymers (e.g. cellulose triacetate and chitin) with IM compounds. Using Density Functional Theory methods, we have studied the adsorption of TNT, DNAN, NTO, NQ, and FOX7 onto cellulose Iα and Iβ, chitin, and cellulose triacetate I (CTA I). Solvent effects on the adsorption were also investigated. Our results show that all contaminants are more strongly adsorbed onto chitin and cellulose Iα than onto CTA I and cellulose Iβ. Dispersion forces were found to be the predominant contribution to the adsorption energies of all contaminants.

  12. 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.

  13. Alterações na cutícula de maçãs ‘Fuji’ e ‘Gala’ em função do tratamento térmico e da armazenagem refrigerada = Changes on ‘Fuji’ and ‘Gala’ apple cuticle as a result of heat treatment and cold storage

    Directory of Open Access Journals (Sweden)

    Cândida Raquel Scherrer Montero

    2010-07-01

    immersion at 58ºC for 30 s, 1 and 2 min.; hot water spraying at 58º C for 30s; chloroform immersion for 30s. Samples were excised to visualize on scanning electron microscope at onset and after three weeks storage at 0oC. During the storage period, cracks of the cuticle layer got wider. Heat acts melting the crystalloidson the cuticle layer, and the melting forms a more homogeneous covering pattern on the apple surface. Heat caused occlusion of fractures by melting waxes, showing this is one of the probableeffects of heat on the fruit, which could be acting as a physical barrier to avoid the entrance of pathogen in the apple, as well as reducing fresh weight loss.

  14. Histochemistry of lectin-binding sites in Halicryptus spinulosus (Priapulida).

    Science.gov (United States)

    Busch, A; Schumacher, U; Storch, V

    2001-02-01

    Priapulida represent one of the phylogenetically oldest multicellular animal groups. In multicellular animals (Metazoa) cell-to-cell and cell-to-matrix interactions are often mediated by carbohydrate residues of glycoconjugates. To analyze the carbohydrate composition of a phylogenetically old species, lectin histochemistry was employed on 5 specimens of the priapulid Halicryptus spinulosus. Many lectins bound to the chitin-containing cuticle, including those specific for carbohydrates other than N-acetylglucosamine, the principle building block of chitin. The connective tissue of the animals contained both N-acetylglucosamine and N-acetylgalactosamine. Mannose residues were widely distributed with the exception of the cuticle, but complex type carbohydrates were not present in the entire animal. Sialic acid residues were only detected in the cuticle and brush border of the intestinal epithelium, while fucose was limited to the cuticle. Thus, the lectin-binding pattern indicated that sugars typical for the linking region of both N- and O-glycoproteins in mammals are also present in H. spinulosus. Carbohydrate residues that are typical for the complex type of N-linked glycans in vertebrates are not present as are carbohydrate residues typical for the termination of O-linked carbohydrate chains. Hence, a truncated form of both N- and O-linked glycosylation is present in H. spinulosus indicating that more complex patterns of glycosylation developed later during evolution.

  15. Electrospun composite nanofiber membrane of poly(l-lactide) and surface grafted chitin whiskers: Fabrication, mechanical properties and cytocompatibility.

    Science.gov (United States)

    Liu, Hua; Liu, Wenjun; Luo, Binghong; Wen, Wei; Liu, Mingxian; Wang, Xiaoying; Zhou, Changren

    2016-08-20

    To improve both the mechanical properties and cytocompatibility of poly(l-lactide) (PLLA), rod-like chitin whiskers (CHWs) were prepared, and subsequently surface modified with l-lactide to obtain grafted CHWs (g-CHWs). Then, CHWs and g-CHWs were further introduced into PLLA matrix to fabricate CHWs/PLLA and g-CHWs/PLLA nanofiber membranes by electrospinning technique. Morphologies and properties of the CHWs and g-CHWs were characterized. The surface-grafted PLLA chains played an important role in improving interfacial interaction between the whiskers and PLLA matrix. The g-CHWs dispersed more uniformly in matrix than CHWs, and the as-prepared g-CHWs/PLLA nanofiber membrane showed relative smooth and uniform fiber. As a result, the tensile strength and modulus of the g-CHWs/PLLA nanofiber membrane were obviously superior to those of the pure PLLA and CHWs/PLLA nanofiber membranes. Cells culture results indicated that g-CHWs/PLLA nanofiber membrane is more effectively in promoting MC3T3-E1 cells adhesion, spreading and proliferation than pure PLLA and CHWs/PLLA nanofiber membrane. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Control of some important soil-borne fungi by chitin associated with chilli (capsicum annuum l.) in lower sindh, pakistan

    International Nuclear Information System (INIS)

    Hussain, F.; Abid, M.; Farzana, A.; Akbar, M.; Shaukat, S.S.

    2013-01-01

    Chilli (Capsicum annuum L.) belongs to the family Solanaceae is one of the most important cash crop of the southern parts of Pakistan. Capsicum is cultivated on a large scale in a lower region of Sindh, Pakistan. It is an important and profitable crop of Pakistan. Several biotic and abiotic stresses affect the productivity of chilli crop. It is infected by a number of diseases particularly soil-borne diseases. Surveys of soil-borne fungal diseases associated with chilli crop in different areas of lower Sindh, including, Hyderabad, Tando Allahyar, Mirpurkhas, Umerkot, Kunri, Samaro, Kot Ghulam uhammad and Digri, were conducted, and chilli plants showing symptoms of wilting were collected. A number of soil-borne root infecting fungi were isolated and identified, such as, Fusarium oxysporum, F. solani, Macrophomina phaseolina, Phytophthora capsici, Pythium sp., and Rhizoctonia solani, from collected disease plants. It was observed that all the major varieties of chillies (i.e., Sanam, Talhari, Ghotaki, Mexi), growing in lower Sindh, were highly susceptible to these fungi. The main objectives of the study were to examine the effectiveness of chitin for the management of soil-borne diseases of chilli plant by different methods, i.e., soil amendment and transplant root dip method. Results indicated that of the two methods, the soil amendment method was more effective while transplant root dip method was less effective. (author)

  17. Influence of chitosan-chitin nanofiber composites on cytoskeleton structure and the proliferation of rat bone marrow stromal cells.

    Science.gov (United States)

    Kiroshka, Victoria V; Petrova, Valentina A; Chernyakov, Daniil D; Bozhkova, Yulia O; Kiroshka, Katerina V; Baklagina, Yulia G; Romanov, Dmitry P; Kremnev, Roman V; Skorik, Yury A

    2017-01-01

    Chitosan scaffolds have gained much attention in various tissue engineering applications, but the effect of their microstructure on cell-material spatial interactions remains unclear. Our objective was to evaluate the effect of chitosan-based matrices doping with chitin nano-whiskers (CNW) on adhesion, spreading, cytoskeleton structure, and proliferation of rat bone marrow stromal cells (BMSCs). The behavior of BMSCs during culture on chitosan-CNW films was determined by the molecular mass, hydrophobicity, porosity, crosslinking degree, protonation degree and molecular structure of the composite chitosan-CNW films. The shape, spreading area, cytoskeleton structure, and proliferation of BMSCs on chitosan matrices with a crystalline structure and high porosity were similar to that observed for BMSCs cultured on polystyrene tissue culture plates. The amorphous polymer structure and high swelling led to a decrease in the spreading area and cell proliferation. Thus, we can control the behavior of cells in culture (adhesion, spreading, and proliferation) by changing the physico-chemical properties of the chitosan-CNW films.

  18. Regulation of the chitin degradation and utilization system by the ChiX small RNA in Serratia marcescens 2170.

    Science.gov (United States)

    Suzuki, Kazushi; Shimizu, Mari; Sasaki, Naomi; Ogawa, Chisana; Minami, Haruka; Sugimoto, Hayuki; Watanabe, Takeshi

    2016-01-01

    Serratia marcescens 2170 produces three different types of chitinases and chitin-binding protein CBP21. We found that transposon insertion into the 5' untranslated region (5' UTR) of chiPQ-ctb led to defective chitinase and CBP21 production. ChiX small RNA possessed the complementary sequence of the 5' UTRs of the chiPQ-ctb and chiR and repressed the expression of chiP and chiR. ChiX was detected in a medium containing glucose, glycerol, GlcNAc, and (GlcNAc)2, but the expression of both chiP and chiR was only observed in a medium containing (GlcNAc)2. ∆chiX mutant produced chitinases, CBP21, and chitobiase without induction. chiP transcripts were more abundant than those of chiR or chiX in a medium containing (GlcNAc)2. These results suggest that the constitutively expressed ChiX binds to the highly abundant chiP 5' UTR, thereby leading to the induction of chiR mRNA translation and the subsequent expression of chitinases and CBP21.

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

    International Nuclear Information System (INIS)

    Fernandes, Kátia F.; Cortijo-Triviño, David; Batista, Karla A.; Ulhoa, Cirano J.; García-Ruiz, Pedro A.

    2013-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Douglas Fernandes Silva

    2015-01-01

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

  1. Effects of the chitin synthesis inhibitor buprofezin on survival and development of immatures of Chrysoperla rufilabris (Neuroptera: Chrysopidae).

    Science.gov (United States)

    Liu, T X; Chen, T Y

    2000-04-01

    Effects of buprofezin (Applaud), a chitin synthesis inhibitor, on survival and development of eggs, three instars, and pupae of Chrysoperla rufilabris (Burmeister) were determined in the laboratory. Buprofezin at three tested concentrations (100, 500, and 1,000 mg [AI]/liter) did not affect the viability and development of eggs when the eggs were treated, or third instars and pupae when those stages were treated. Although the degree of effects by buprofezin on larvae varied with instar, buprofezin at the higher concentrations (500 and 1,000 mg [AI]/liter) reduced survival rates 17-47% and prolonged the overall development from first instars to adult emergence by 2 or 3 d when first instars were treated, indicating that the first instar is the most vulnerable stage. When second instars were treated, the survival of C. rufilabris from second instars to pupae was not significantly affected. However, the developmental time from second instar to adult emergence was longer in the treatments with the highest concentration (1,000 mg [AI]/liter) than that with the lowest concentration (100 mg [AI]/liter). The compatibility of buprofezin with natural enemies in integrated pest management programs is discussed.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-07-01

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

  3. Morphological changes of the filamentous fungus Mucor mucedo and inhibition of chitin synthase activity induced by anethole.

    Science.gov (United States)

    Yutani, Masahiro; Hashimoto, Yukie; Ogita, Akira; Kubo, Isao; Tanaka, Toshio; Fujita, Ken-ichi

    2011-11-01

    trans-Anethole (anethole), a major component of anise oil, has a broad antimicrobial spectrum with antimicrobial activity relatively weaker than those of well-known antibiotics, and significantly enhances the antifungal activity of polygodial and dodecanol against the baker's yeast Saccharomyces cerevisiae and human pathogenic yeast Candida albicans. However, the antifungal mechanism of anethole is unresolved. Anethole demonstrated antifungal activity against the filamentous fungus, Mucor mucedo IFO 7684, accompanied by hyphal morphological changes such as swollen hyphae at the tips. Its minimum growth inhibitory concentration was 0.625 mM. A hyperosmotic condition (1.2 M sorbitol) restricted the induction of morphological changes, while hypoosmotic treatment (distilled water) induced bursting of hyphal tips and leakage of cytoplasmic constituents. Furthermore, anethole dose-dependently inhibited chitin synthase (CHS) activity in permeabilized hyphae in an uncompetitive manner. These results suggest that the morphological changes of M. mucedo could be explained by the fragility of cell walls caused by CHS inhibition. Copyright © 2011 John Wiley & Sons, Ltd.

  4. 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.

  5. 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 uri...

  6. Obtenção e caracterização de α-quitina e quitosanas de cascas de Macrobrachium rosembergii Preparation and characterization of α-chitin and chitosan from the shells of Macrobrachium rosembergii

    Directory of Open Access Journals (Sweden)

    Marcos Valério Battisti

    2008-01-01

    Full Text Available The shells of Macrobrachium rosenbergii were submitted to deproteinization (Dp and demineralization (Dm aiming the extraction of α-chitin. The different parts of the shells were processed independently by carrying out sequence 1 (Dp/Dm and sequence 2 (Dm/Dp. Both sequences allowed the extraction of chitins with low contents of calcium and magnesium, regardless of the part being processed. The sequence 1 lead to higher extraction yields while sequence 2 resulted in lower contents of inorganic compounds. Extensively deacetylated chitosans (GA<10% of medium molecular weight (0,9 x 10(5 < Mv < 2 x 10(5 g/mol resulted from the deacetylation of chitin.

  7. The Impact of Selection with Diflubenzuron, a Chitin Synthesis Inhibitor, on the Fitness of Two Brazilian Aedes aegypti Field Populations

    Science.gov (United States)

    Belinato, Thiago Affonso; Valle, Denise

    2015-01-01

    Several Aedes aegypti field populations are resistant to neurotoxic insecticides, mainly organophoshates and pyrethroids, which are extensively used as larvicides and adulticides, respectively. Diflubenzuron (DFB), a chitin synthesis inhibitor (CSI), was recently approved for use in drinking water, and is presently employed in Brazil for Ae. aegypti control, against populations resistant to the organophosphate temephos. However, tests of DFB efficacy against field Ae. aegypti populations are lacking. In addition, information regarding the dynamics of CSI resistance, and characterization of any potential fitness effects that may arise in conjunction with resistance are essential for new Ae. aegypti control strategies. Here, the efficacy of DFB was evaluated for two Brazilian Ae. aegypti populations known to be resistant to both temephos and the pyrethroid deltamethrin. Laboratory selection for DFB resistance was then performed over six or seven generations, using a fixed dose of insecticide that inhibited 80% of adult emergence in the first generation. The selection process was stopped when adult emergence in the diflubenzuron-treated groups was equivalent to that of the control groups, kept without insecticide. Diflubenzuron was effective against the two Ae. aegypti field populations evaluated, regardless of their resistance level to neurotoxic insecticides. However, only a few generations of DFB selection were sufficient to change the susceptible status of both populations to this compound. Several aspects of mosquito biology were affected in both selected populations, indicating that diflubenzuron resistance acquisition is associated with a fitness cost. We believe that these results can significantly contribute to the design of control strategies involving the use of insect growth regulators. PMID:26107715

  8. Use of chitin and chitosan to produce new chitooligosaccharides by chitinase Chit42: enzymatic activity and structural basis of protein specificity.

    Science.gov (United States)

    Kidibule, Peter Elias; Santos-Moriano, Paloma; Jiménez-Ortega, Elena; Ramírez-Escudero, Mercedes; Limón, M Carmen; Remacha, Miguel; Plou, Francisco José; Sanz-Aparicio, Julia; Fernández-Lobato, María

    2018-03-22

    Chitinases are ubiquitous enzymes that have gained a recent biotechnological attention due to their ability to transform biological waste from chitin into valued chito-oligomers with wide agricultural, industrial or medical applications. The biological activity of these molecules is related to their size and acetylation degree. Chitinase Chit42 from Trichoderma harzianum hydrolyses chitin oligomers with a minimal of three N-acetyl-D-glucosamine (GlcNAc) units. Gene chit42 was previously characterized, and according to its sequence, the encoded protein included in the structural Glycoside Hydrolase family GH18. Chit42 was expressed in Pichia pastoris using fed-batch fermentation to about 3 g/L. Protein heterologously expressed showed similar biochemical properties to those expressed by the natural producer (42 kDa, optima pH 5.5-6.5 and 30-40 °C). In addition to hydrolyse colloidal chitin, this enzyme released reducing sugars from commercial chitosan of different sizes and acetylation degrees. Chit42 hydrolysed colloidal chitin at least 10-times more efficiently (defined by the k cat /K m ratio) than any of the assayed chitosan. Production of partially acetylated chitooligosaccharides was confirmed in reaction mixtures using HPAEC-PAD chromatography and mass spectrometry. Masses corresponding to (D-glucosamine) 1-8 -GlcNAc were identified from the hydrolysis of different substrates. Crystals from Chit42 were grown and the 3D structure determined at 1.8 Å resolution, showing the expected folding described for other GH18 chitinases, and a characteristic groove shaped substrate-binding site, able to accommodate at least six sugar units. Detailed structural analysis allows depicting the features of the Chit42 specificity, and explains the chemical nature of the partially acetylated molecules obtained from analysed substrates. Chitinase Chit42 was expressed in a heterologous system to levels never before achieved. The enzyme produced small partially acetylated

  9. A glycosylphosphatidylinositol anchor is required for membrane localization but dispensable for cell wall association of chitin deacetylase 2 in Cryptococcus neoformans.

    Science.gov (United States)

    Gilbert, Nicole M; Baker, Lorina G; Specht, Charles A; Lodge, Jennifer K

    2012-01-01

    Cell wall proteins (CWPs) mediate important cellular processes in fungi, including adhesion, invasion, biofilm formation, and flocculation. The current model of fungal cell wall organization includes a major class of CWPs covalently bound to β-1,6-glucan via a remnant of a glycosylphosphatidylinositol (GPI) anchor. This model was established by studies of ascomycetes more than a decade ago, and relatively little work has been done with other fungi, although the presumption has been that proteins identified in the cell wall which contain a predicted GPI anchor are covalently linked to cell wall glucans. The pathogenic basidiomycete Cryptococcus neoformans encodes >50 putatively GPI-anchored proteins, some of which have been identified in the cell wall. One of these proteins is chitin deacetylase 2 (Cda2), an enzyme responsible for converting chitin to chitosan, a cell wall polymer recently established as a virulence factor for C. neoformans infection of mammalian hosts. Using a combination of biochemistry, molecular biology, and genetics, we show that Cda2 is GPI anchored to membranes but noncovalently associated with the cell wall by means independent of both its GPI anchor and β-1,6-glucan. We also show that Cda2 produces chitosan when localized to the plasma membrane, but association with the cell wall is not essential for this process, thereby providing insight into the mechanism of chitosan biosynthesis. These results increase our understanding of the surface of C. neoformans and provide models of cell walls likely applicable to other undercharacterized basidiomycete pathogenic fungi. The surface of a pathogenic microbe is a major interface with its host. In fungi, the outer surface consists of a complex matrix known as the cell wall, which includes polysaccharides, proteins, and other molecules. The mammalian host recognizes many of these surface molecules and mounts appropriate responses to combat the microbial infection. Cryptococcus neoformans is a

  10. Contributor Form

    Directory of Open Access Journals (Sweden)

    Chief Editor

    2014-09-01

    to produce preprints or reprints and translate into languages other than English for sale or free distribution; and 4 the right to republish the work in a collection of articles in any other mechanical or electronic format. We give the rights to the corresponding author to make necessary changes as per the request of the journal, do the rest of the correspondence on our behalf and he/she will act as the guarantor for the manuscript on our behalf. All persons who have made substantial contributions to the work reported in the manuscript, but who are not contributors, are named in the Acknowledgment and have given me/us their written permission to be named. If I/we do not include an Acknowledgment that means I/we have not received substantial contributions from non-contributors and no contributor has been omitted.S NoAuthors' NamesContribution (IJCME Guidelines{1 substantial contributions to conception and design, acquisition of data, or analysis and interpretation of data; 2 drafting the article or revising it critically for important intellectual content; and 3 final approval of the version to be published. Authors should meet conditions 1, 2, and 3}.SignatureDate                              Note: All the authors are required to sign independently in this form in the sequence given above. In case an author has left the institution/country and whose whereabouts are not known, the senior author may sign on his/her behalf taking the responsibility.No addition/deletion/ or any change in the sequence of the authorship will be permissible at a later stage, without valid reasons and permission of the Editor.If the authorship is contested at any stage, the article will be either returned or will not be processed for publication till the issue is solved.Maximum up to 4 authors for short communication and up to 6 authors for original article.

  11. Contributors Form

    Directory of Open Access Journals (Sweden)

    Chief Editor

    2016-06-01

    to produce preprints or reprints and translate into languages other than English for sale or free distribution; and 4 the right to republish the work in a collection of articles in any other mechanical or electronic format. We give the rights to the corresponding author to make necessary changes as per the request of the journal, do the rest of the correspondence on our behalf and he/she will act as the guarantor for the manuscript on our behalf. All persons who have made substantial contributions to the work reported in the manuscript, but who are not contributors, are named in the Acknowledgment and have given me/us their written permission to be named. If I/we do not include an Acknowledgment that means I/we have not received substantial contributions from non-contributors and no contributor has been omitted.S NoAuthors' NamesContribution (IJCME Guidelines{1 substantial contributions to conception and design, acquisition of data, or analysis and interpretation of data; 2 drafting the article or revising it critically for important intellectual content; and 3 final approval of the version to be published. Authors should meet conditions 1, 2, and 3}.SignatureDate                              Note: All the authors are required to sign independently in this form in the sequence given above. In case an author has left the institution/country and whose whereabouts are not known, the senior author may sign on his/her behalf taking the responsibility.No addition/deletion/ or any change in the sequence of the authorship will be permissible at a later stage, without valid reasons and permission of the Editor.If the authorship is contested at any stage, the article will be either returned or will not be processed for publication till the issue is solved.Maximum up to 4 authors for short communication and up to 6 authors for original article.

  12. Antibodies against glucan, chitin, and Saccharomyces cerevisiae mannan as new biomarkers of Candida albicans infection that complement tests based on C. albicans mannan.

    Science.gov (United States)

    Sendid, B; Dotan, N; Nseir, S; Savaux, C; Vandewalle, P; Standaert, A; Zerimech, F; Guery, B P; Dukler, A; Colombel, J F; Poulain, D

    2008-12-01

    Antibodies against Saccharomyces cerevisiae mannan (ASCA) and antibodies against synthetic disaccharide fragments of glucans (ALCA) and chitin (ACCA) are biomarkers of Crohn's disease (CD). We previously showed that Candida albicans infection generates ASCA. Here, we explored ALCA and ACCA as possible biomarkers of invasive C. albicans infection (ICI). ASCA, ALCA, ACCA, and Candida mannan antigen and antibody detection tests were performed on 69 sera obtained sequentially from 18 patients with ICIs proven by blood culture, 59 sera from CD patients, 47 sera from hospitalized subjects colonized by Candida species (CZ), and 131 sera from healthy controls (HC). ASCA, ALCA, and ACCA levels in CD and ICI patients were significantly different from those in CZ and HC subjects (PACCA, and Platelia Candida tests, 100% of ICIs were detected, with the kinetics of the antibody response depending on the patient during the time course of infection. A large number of sera presented with more than three positive tests. This is the first evidence that the detection of antibodies against chitin and glucans has diagnostic value in fungal infections and that these tests can complement more specific tests. Future trials are necessary to assess the value of these tests in multiparametric analysis, as well as their pathophysiological relevance.

  13. 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.

  14. Control of the Root-Knot Nematode (Meloidogyne spp. on Cucumber by a Liquid Bio-Formulation Containing Chitinolytic Bacteria, Chitin and Their Products

    Directory of Open Access Journals (Sweden)

    Woo Jong Ha

    2014-06-01

    Full Text Available A liquid bio-formulation containing chitinolytic bacteria, chitin and their products was assessed for its potential biological control against root-knot nematodes on cucumber. The bio-formulation was prepared by cultures of three chitinolytic bacteria, Chromobacterium sp. strain C-61, Lysobacter engymogenes and Serratia plymuthica in minimal medium supplemented with chitin. Under pot conditions, the bio-formulation showed better growth of cucumber plants, and less root galls and population density of Meloidogyne spp. than control media without the bio-formulation. In a greenhouse, 75-fold diluted bio-formulations were treated instead of water around cucumber plants through hoses for drip irrigation six times at 5-day intervals from the transplanting date. After 30 and 60 days, the treatment provided about 7% and 10% enhancement in the plant height and about 78% and 69% reduction in population density of Meloidogyne spp. in the rhizosphere, respectively. In addition, the experiments showed that the control effects occurred only in the soils contacted with the bio-formulation. Undiluted bio-formulations were drenched three times at 10-day intervals around cucumber plants severely infested with Meloidogyne spp. The treatment showed about 37% plant enhancement without dead plants compared with 37% death in the untreated control, and about 82% nematode reduction. These results suggest that the bio-formulation can be practically used to control the root-knot nematode on cucumber.

  15. Chitinolytic Streptomyces vinaceusdrappus S5MW2 isolated from Chilika lake, India enhances plant growth and biocontrol efficacy through chitin supplementation against Rhizoctonia solani.

    Science.gov (United States)

    Yandigeri, Mahesh S; Malviya, Nityanand; Solanki, Manoj Kumar; Shrivastava, Pooja; Sivakumar, G

    2015-08-01

    A chitinolytic actinomycete Streptomyces vinaceusdrappus S5MW2 was isolated from water sample of Chilika lake, India and identified using 16S rRNA gene sequencing. It showed in vitro antifungal activity against the sclerotia producing pathogen Rhizoctonia solani in a dual culture assay and by chitinase enzyme production in a chitin supplemented minimal broth. Moreover, isolate S5MW2 was further characterized for biocontrol (BC) and plant growth promoting features in a greenhouse experiment with or without colloidal chitin (CC). Results of greenhouse experiment showed that CC supplementation with S5MW2 showed a significant growth of tomato plants and superior disease reduction as compared to untreated control and without CC treated plants. Moreover, higher accumulation of chitinase also recovered in the CC supplemented plants. Significant effect of CC also concurred with the Analysis of Variance of greenhouse parameters. These results show that the a marine antagonist S5MW2 has BC efficiency against R. solani and chitinase enzyme played important role in plant resistance.

  16. Nitrogen and sulfur dual-doped chitin-derived carbon/graphene composites as effective metal-free electrocatalysts for dye sensitized solar cells

    Science.gov (United States)

    Di, Yi; Xiao, Zhanhai; Yan, Xiaoshuang; Ru, Geying; Chen, Bing; Feng, Jiwen

    2018-05-01

    The photovoltaic performance of dye-sensitized solar cell (DSSC) is strongly influenced by the electrocatalytic ability of its counter electrode (CE) materials. To obtain the affordable and high-performance electrocatalysts, the N/S dual-doped chitin-derived carbon materials SCCh were manufactured via in-situ S-doped method in the annealing process, where richer active sites are created compared to the pristine chitin-derived carbon matrix CCh, thus enhancing the intrinsic catalytic activity of carbon materials. When SCCh is incorporated with graphene, the yielded composites hold a further boosted catalytic activity due to facilitating the electronic fast transfer. The DSSC assembled with the optimizing rGO-SCCh-3 composite CE shows a favourable power conversion efficiency of 6.36%, which is comparable with that of the Pt-sputtering electrode (6.30%), indicate of the outstanding I3- reduction ability of the composite material. The electrochemical characterizations demonstrate that the low charge transfer resistance and excellent electrocatalytic activity all contribute to the superior photovoltaic performance. More importantly, the composite CE exhibits good electrochemical stability in the practical operation. In consideration of the low cost and the simple preparation procedure, the present metal-free carbonaceous composites could be used as a promising counter electrode material in future large scale production of DSSCs.

  17. In roots of Arabidopsis thaliana, the damage-associated molecular pattern AtPep1 is a stronger elicitor of immune signalling than flg22 or the chitin heptamer.

    Directory of Open Access Journals (Sweden)

    Lorenzo Poncini

    Full Text Available Plants interpret their immediate environment through perception of small molecules. Microbe-associated molecular patterns (MAMPs such as flagellin and chitin are likely to be more abundant in the rhizosphere than plant-derived damage-associated molecular patterns (DAMPs. We investigated how the Arabidopsis thaliana root interprets MAMPs and DAMPs as danger signals. We monitored root development during exposure to increasing concentrations of the MAMPs flg22 and the chitin heptamer as well as of the DAMP AtPep1. The tissue-specific expression of defence-related genes in roots was analysed using a toolkit of promoter::YFPN lines reporting jasmonic acid (JA-, salicylic acid (SA-, ethylene (ET- and reactive oxygen species (ROS- dependent signalling. Finally, marker responses were analysed during invasion by the root pathogen Fusarium oxysporum. The DAMP AtPep1 triggered a stronger activation of the defence markers compared to flg22 and the chitin heptamer. In contrast to the tested MAMPs, AtPep1 induced SA- and JA-signalling markers in the root and caused a severe inhibition of root growth. Fungal attack resulted in a strong activation of defence genes in tissues close to the invading fungal hyphae. The results collectively suggest that AtPep1 presents a stronger danger signal to the Arabidopsis root than the MAMPs flg22 and chitin heptamer.

  18. Films of chitin, chitosan and cellulose obtained from aqueous suspension treated by irradiation of high intensity ultrasound; Filmes de quitina, quitosana e celullose de sisal obtidos a partir de suspensoes aquosas tratadas com irradiacao de ultrassom de alta intensidade

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, Erika V.R.; Mariano, Mario S.; Campana-Filho, Sergio P., E-mail: erikavi@iqsc.usp.br [Universidade de Sao Paulo (IQSC/USP), Instituto de Quimica de Sao Carlos, Sao Carlos, SP (Brazil)

    2011-07-01

    Films of chitin, chitin/chitosan and chitin/sisal cellulose were obtained by casting their aqueous suspensions previously treated with irradiation of high intensity ultrasound. The films were characterized for surface morphology by scanning electron microscopy and it is possible notice that the films containing chitosan are much more homogeneous. The thermal behavior of the films was evaluated by dynamic mechanical thermal analysis, differential scanning calorimetry, and thermogravimetric analysis and revealing similarity in comparison with the thermal behavior of polysaccharide isolated. The tensile strength was determined and the film containing chitosan showed the best result when compared to other films. The crystallinity index of the films analyzed by X-ray diffraction showed that the films are amorphous material. The analysis by infrared spectroscopy showed that treatment of aqueous suspensions of polysaccharides with irradiation of high intensity ultrasound did not change the chemical structure of polymers. The crystallinity index was determined by X-ray diffraction, revealing that the films are amorphous materials. The results of this study indicate the possibility of processing of chitin, chitosan and cellulose, polysaccharides whose solubilities are limited to a few solvent systems, by treating their aqueous suspensions with high intensity ultrasound. (author)

  19. The cell wall stress response in Aspergillus niger involves increased expression of the glutamine: Fructose-6-phosphate amidotransferase-encoding gene (gfaA) and increased deposition of chitin in the cell wall

    NARCIS (Netherlands)

    Ram, A.F.J.; Arentshorst, M.; Damveld, R.A.; Kuyk, P.A. van; Klis, F.M.; Hondel, C.A.M.J.J. van den

    2004-01-01

    Perturbation of cell wall synthesis in Saccharomyces cerevisiae, either by mutations in cell wall synthesis-related genes or by adding compounds that interfere with normal cell wall assembly, triggers a compensatory response to ensure cell wall integrity. This response includes an increase in chitin

  20. Densified waste form and method for forming

    Science.gov (United States)

    Garino, Terry J.; Nenoff, Tina M.; Sava Gallis, Dorina Florentina

    2015-08-25

    Materials and methods of making densified waste forms for temperature sensitive waste material, such as nuclear waste, formed with low temperature processing using metallic powder that forms the matrix that encapsulates the temperature sensitive waste material. The densified waste form includes a temperature sensitive waste material in a physically densified matrix, the matrix is a compacted metallic powder. The method for forming the densified waste form includes mixing a metallic powder and a temperature sensitive waste material to form a waste form precursor. The waste form precursor is compacted with sufficient pressure to densify the waste precursor and encapsulate the temperature sensitive waste material in a physically densified matrix.

  1. Characterization of chitinous polyaminoglycosides

    Czech Academy of Sciences Publication Activity Database

    Tishchenko, Galina; Šimůnek, Jiří; Brus, Jiří; Netopilík, Miloš; Walterová, Zuzana; Pekárek, Michal; Lenfeld, Jiří; Koppová, Ingrid

    2009-01-01

    Roč. 103, č. 9 (2009), s. 777 ISSN 0009-2770. [International Conference on Polysaccharides-Glycoscience /5./. 11.11.2009-13.11.2009, Praha] R&D Projects: GA ČR(CZ) GA525/08/0803 Institutional research plan: CEZ:AV0Z40500505 Keywords : chitooligosaccharides * low-molecular-weight chitosan * oxidative depolymerization Subject RIV: CD - Macromolecular Chemistry

  2. Efeito de Aditivos na Desacetilação de Quitina Effects from Additives on Deacetylation of Chitin

    Directory of Open Access Journals (Sweden)

    Sérgio P. Campana Fº

    2001-01-01

    Full Text Available Reações de desacetilação de quitina comercial em suspensão aquosa de hidróxido de sódio foram realizadas em etapa única de 6 horas a 115°C. Os efeitos de aditivos (boro hidreto de sódio ou antraquinona e de borbulhamento de gases inertes (nitrogênio ou argônio sobre as características das amostras desacetiladas foram avaliados. A espectroscopia de ressonância magnética nuclear de hidrogênio e viscosimetria capilar foram empregadas para determinações de graus médios de acetilação e de viscosidades intrínsecas de quitosanas, respectivamente. A difração de raiosX foi empregada para comparar as amostras quanto à cristalinidade e os espectros no infravermelho foram comparados para avaliar modificações estruturais decorrentes da reação de desacetilação. As quitosanas mais cristalinas foram obtidas quando um dos gases inertes foi borbulhado no meio durante a reação de desacetilação. Amostras ligeiramente mais desacetiladas foram obtidas na ausência de qualquer aditivo, mas severa despolimerização ocorreu nesses casos. A adição de boro hidreto de sódio ao meio reacional reduziu significativamente a despolimerização, mas a presença de antraquinona e o borbulhamento de nitrogênio, ou de argônio, não surtiu qualquer efeito, sugerindo que a presença de oxigênio não é um pré-requisito para a ocorrência de despolimerização.Deacetylation reactions of commercial chitin were carried out in aqueous sodium hydroxide solution at 115°C for 6 hours. The effect from additives (sodium borohydride or anthraquinone and of bubbling inert gas (nitrogen or argon on the characteristics of deacetylated samples were evaluated. Average degrees of acetylation and intrinsic viscosity were determined by ¹H NMR spectroscopy and capillary viscometry, respectively. X-ray diffraction was employed to evaluate changes in crystallinity and infrared spectroscopy was used to monitor structural changes due to deacetylation. The

  3. Synthesis of Chitin Oligosaccharides Using Dried Stenotrophomonas maltophilia Cells Containing a Transglycosylation Reaction-Catalyzing β-N-Acetylhexosaminidase as a Whole-Cell Catalyst.

    Science.gov (United States)

    Uehara, Asaki; Takahashi, Narumi; Moriyama, Mei; Hirano, Takako; Hakamata, Wataru; Nishio, Toshiyuki

    2018-02-01

    Bacterial strain NYT501, which we previously isolated from soil, was identified as Stenotrophomonas maltophilia, and it was confirmed that this strain produces an intracellular β-N-acetylhexosaminidase exhibiting transglycosylation activity. Several properties of this enzyme were characterized using a partially purified enzyme preparation. Using N,N'-diacetylchitobiose (GlcNAc) 2 and N,N',N″-triacetylchitotriose (GlcNAc) 3 as substrates and dried cells of this bacterium as a whole-cell catalyst, chitin oligosaccharides of higher degrees of polymerization were synthesized. (GlcNAc) 3 was generated from (GlcNAc) 2 as the major transglycosylation product, and a certain amount of purified sample of the trisaccharide was obtained. By contrast, in the case of the reaction using (GlcNAc) 3 as a substrate, the yield of higher-degree polymerization oligosaccharides was comparatively low.

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

    Directory of Open Access Journals (Sweden)

    Feng Xue

    2015-01-01

    Full Text Available We examined the restorative effect of modified biodegradable chitin conduits in combination with bone marrow mesenchymal stem cell transplantation after right spinal cord hemisection injury. Immunohistochemical staining revealed that biological conduit sleeve bridging reduced glial scar formation and spinal muscular atrophy after spinal cord hemisection. Bone marrow mesenchymal stem cells survived and proliferated after transplantation in vivo, and differentiated into cells double-positive for S100 (Schwann cell marker and glial fibrillary acidic protein (glial cell marker at 8 weeks. Retrograde tracing showed that more nerve fibers had grown through the injured spinal cord at 14 weeks after combination therapy than either treatment alone. Our findings indicate that a biological conduit combined with bone marrow mesenchymal stem cell transplantation effectively prevented scar formation and provided a favorable local microenvironment for the proliferation, migration and differentiation of bone marrow mesenchymal stem cells in the spinal cord, thus promoting restoration following spinal cord hemisection injury.

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

    Science.gov (United States)

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

    2015-01-01

    We examined the restorative effect of modified biodegradable chitin conduits in combination with bone marrow mesenchymal stem cell transplantation after right spinal cord hemisection injury. Immunohistochemical staining revealed that biological conduit sleeve bridging reduced glial scar formation and spinal muscular atrophy after spinal cord hemisection. Bone marrow mesenchymal stem cells survived and proliferated after transplantation in vivo, and differentiated into cells double-positive for S100 (Schwann cell marker) and glial fibrillary acidic protein (glial cell marker) at 8 weeks. Retrograde tracing showed that more nerve fibers had grown through the injured spinal cord at 14 weeks after combination therapy than either treatment alone. Our findings indicate that a biological conduit combined with bone marrow mesenchymal stem cell transplantation effectively prevented scar formation and provided a favorable local microenvironment for the proliferation, migration and differentiation of bone marrow mesenchymal stem cells in the spinal cord, thus promoting restoration following spinal cord hemisection injury. PMID:25788929

  6. A chitin-binding lectin from Moringa oleifera seeds (WSMoL) impairs the digestive physiology of the Mediterranean flour larvae, Anagasta kuehniella.

    Science.gov (United States)

    de Oliveira, Caio Fernando Ramalho; de Moura, Maiara Celine; Napoleão, Thiago Henrique; Paiva, Patrícia Maria Guedes; Coelho, Luana Cassandra Breitenbach Barroso; Macedo, Maria Lígia Rodrigues

    2017-10-01

    Biotechnological techniques allow the investigation of alternatives to outdated chemical insecticides for crop protection; some investigations have focused on the identification of molecules tailored from nature for this purpose. We, herein, describe the negative effects of water-soluble lectin from Moringa oleifera seeds (WSMoL) on Anagasta kuehniella development. The chitin-binding lectin, WSMoL, impaired the larval weight gain by 50% and affected the activity of the pest's major digestive enzymes. The commitment of the digestive process became evident after controlled digestion studies, where the capacity of protein digestion was compromised by >90%. Upon acute exposure, the lectin was not resistant to digestion; however, chronic ingestion of WSMoL was able to reverse this feature. Thus, we show that resistance to digestion may not be a prerequisite for a lectin's ability to exert negative effects on larval physiology. The mechanism of action of WSMoL involves binding to chitin with possible disruption to the peritrophic membrane, causing disorder between the endo- and ectoperitrophic spaces. Additionally, results suggest that WSMoL may trigger apoptosis in gut cells, leading to the lower enzymatic activity observed in WSMoL-fed larvae. Although assays employing an artificial diet did not demonstrate effects of WSMoL on A. kuehniella mortality, this lectin may hold potential for exerting insecticide effects on other pest insects, as well for use in other experimental approaches, such as WSMoL-expressing plants. Moreover, the use