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Farooqahmed S. Kittur - One of the best experts on this subject based on the ideXlab platform.
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Chitin - The Undisputed Biomolecule of Great Potential
Critical Reviews in Food Science and Nutrition, 2003Co-Authors: Rudrapatnam N. Tharanathan, Farooqahmed S. KitturAbstract:Of the truly abundant polysaccharides in Nature, only Chitin has yet to find utilization in large quantity. Chitin is the second most abundant natural biopolymer derived from exoskeletons of crustaceans and also from cell walls of fungi and insects. Chitin is a linear beta 1,4-linked polymer of N-acetyl-D-glucosamine (GlcNAc), whereas chitosan, a copolymer of GlcNAc (approximately 20%) and glucosamine (GlcN, 80%) residues, is a product derived from de-N-acetylation of Chitin in the presence of hot alkali. Chitosan is, in fact, a collective name representing a family of de-N-acetylated Chitins deacetylated to different degrees. Both Chitin/chitosan and their modified derivatives find extensive applications in medicine, agriculture, food, and non-food industries as well. They have emerged as a new class of physiological materials of highly sophisticated functions. Their application versatility is a great challenge to the scientific community and to industry. All these are the result of their versatile biological activity, excellent biocompatibility, and complete biodegradability in combination with low toxicity. Commercial availability of high-purity forms of Chitin/chitosan and the continuous appearance of new types of Chitin/chitosan derivatives with more and more useful and specific properties have led to an unlimited R&D efforts on this most versatile amino polysaccharide, Chitin to find new applications, which are necessary to realize its full potential. Incidentally, this too has become an environmental priority. No doubt, Chitin is surely an undisputed biomolecule of great potential.
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Chitin the undisputed biomolecule of great potential
Critical Reviews in Food Science and Nutrition, 2003Co-Authors: Rudrapatnam N. Tharanathan, Farooqahmed S. KitturAbstract:Of the truly abundant polysaccharides in Nature, only Chitin has yet to find utilization in large quantity. Chitin is the second most abundant natural biopolymer derived from exoskeletons of crustaceans and also from cell walls of fungi and insects. Chitin is a linear β1,4-linked polymer of N-acetyl-D-glucosamine (GlcNAc), whereas chitosan, a copolymer of GlcNAc (∼20%) and glulcosamine (GlcN, 80%) residues, is a product derived from de-N-acetylation of Chitin in the presence of hot alkali. Chitosan is, in fact, a collective name representing a family of de-N-acetylated Chitins deacetylated to different degrees. Both Chitin/chitosan and their modified derivatives find extensive applications in medicine, agriculture, food, and non-food industries as well. They have emerged as a new class of physiological materials of highly sophisticated functions. Their application versatility is a great challenge to the scientific community and to industry. All these are the result of their versatile biological activity, ...
Akira Isogai - One of the best experts on this subject based on the ideXlab platform.
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Chitin nanocrystals prepared by oxidation of α-Chitin using the O2/laccase/TEMPO system.
Carbohydrate Polymers, 2018Co-Authors: Jie Jiang, Tsuguyuki Saito, Wenbo Ye, Juan Yu, Akira IsogaiAbstract:Abstract Laccase mediator oxidation was applied to Chitin at pH 6.8 and 30 °C to prepare Chitin nanocrystals with a catalytic amount of 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO). When 40 mM TEMPO and a total of 500 U laccase were added to 1 g Chitin, the yield of water-insoluble oxidized Chitin was more than 95%, and the carboxylate content was 0.43 mmol/g. Adsorption of laccase molecules on Chitin particles occurred in a buffer at pH 6.8, which may have been caused by electrostatic interactions between positively charged C2-ammonium groups of Chitin and anionically charged groups of laccase. Rod-like Chitin nanocrystals (ChNCs) were obtained with average lengths and widths of 480 ± 200 nm and 24 ± 17 nm, respectively, by sonication of the oxidized Chitin/water suspensions. The O2/laccase/TEMPO oxidation caused no decrease in the degree of N-acetylation or the crystallinity of the original Chitin based on FTIR and X-ray diffraction data.
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individual Chitin nano whiskers prepared from partially deacetylated α Chitin by fibril surface cationization
Carbohydrate Polymers, 2010Co-Authors: Tsuguyuki Saito, Akira IsogaiAbstract:Abstract α-Chitin was partially deacetylated to degrees of N-acetylation (DNAc) 0.74–0.70 by 33% NaOH treatment at 90 °C for 2–4 h. Solid recovery ratios or yields of the products were 85–90%. Crystallinity index and crystal size of the original α-Chitin were maintained, showing that the partial deacetylation mostly occurred on the α-Chitin crystallite surfaces. Transparent and highly viscous liquids were obtained by disintegration of the partially deacetylated Chitins in water at pH 3–4. Transmission electron microscopy (TEM) revealed that the liquids consisted mostly of individual nano-whiskers with average width and length 6.2 ± 1.1 and 250 ± 140 nm, respectively. Some α-Chitin nano-fibrils of more than 500 nm in length were also detected in TEM images. Because the DNAc values 0.74–0.70 correspond to 1.34–1.56 mmol g−1 C2-amino group contents, high cationic charges might be formed on the α-Chitin fibril surfaces in high density by protonation in water at pH 3–4.
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Chitin nanocrystals prepared by tempo mediated oxidation of α Chitin
Biomacromolecules, 2008Co-Authors: Tsuguyuki Saito, Akira IsogaiAbstract:Chitin nanocrystals dispersed in water were successfully prepared by 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO) mediated oxidation of α-Chitin in water at pH 10 under specific conditions, followed by ultrasonic treatment. When the amount of NaClO added as co-oxidant in the oxidation was 5.0 mmol/g of Chitin, the weight percentage of the water-insoluble fraction in the TEMPO-oxidized Chitin was 90%, and its carboxylate content reached 0.48 mmol/g. Since the TEMPO-oxidized Chitin thus prepared had a crystallinity as high as that of the original α-Chitin, the C6 carboxylate groups formed by TEMPO-mediated oxidation can be regarded as being present only on the Chitin crystallite surfaces. No N-deacetylation occurred on the TEMPO-oxidized Chitins. When the TEMPO-oxidized Chitin was subjected to ultrasonic treatment in water, mostly individualized Chitin nanocrystals were obtained, and the average nanocrystal length and width were 340 and 8 nm, respectively.
Murat Kaya - One of the best experts on this subject based on the ideXlab platform.
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On chemistry of γ-Chitin
Carbohydrate Polymers, 2017Co-Authors: Murat Kaya, Talat Baran, Hermann Ehrlich, Idris Sargin, Muhammad Mujtaba, Asier M. Salaberria, Chris T. Amemiya, Roberta Galli, Lalehan Akyuz, Jalel LabidiAbstract:Abstract The biological material, Chitin, is present in nature in three allomorphic forms: α, β and γ. Whereas most studies have dealt with α- and β-Chitin, only few investigations have focused on γ-Chitin, whose structural and physicochemical properties have not been well delineated. In this study, Chitin obtained for the first time from the cocoon of the moth ( Orgyia dubia ) was subjected to extensive physicochemical analyses and examined, in parallel, with α-Chitin from exoskeleton of a freshwater crab and β-Chitin from cuttlebone of the common cuttlefish. Our results, which are supported by 13 C CP-MAS NMR, XRD, FT-IR, Raman spectroscopy, TGA, DSC, SEM, AFM, Chitinase digestive test and elemental analysis, verify the authenticity of γ-Chitin. Further, quantum chemical calculations were conducted on all three allomorphic forms, and, together with our physicochemical analyses, demonstrate that γ-Chitin is distinct, yet closer in structure to α-Chitin than β-Chitin.
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high similarity in physicochemical properties of Chitin and chitosan from nymphs and adults of a grasshopper
International Journal of Biological Macromolecules, 2016Co-Authors: Sevil Erdogan, Murat KayaAbstract:Abstract 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 (7.2 kDa) and nymph (5.6 kDa) 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.
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First Chitin extraction from Plumatella repens (Bryozoa) with comparison to Chitins of insect and fungal origin.
International Journal of Biological Macromolecules, 2015Co-Authors: Murat Kaya, Vykintas Baublys, Ingrida Šatkauskienė, Bahar Akyuz, Esra Bulut, Vaida TubelytėAbstract:Abstract Chitin immediately suggests the representatives of the kingdom Fungi, as well as such phyla as Annelida, Mollusca, Porifera, Cnidaria and, mostly, Arthropoda. Although Bryozoa also represents a Chitin-containing phylum, no study has been developed yet on the isolation or characterization of the Chitin from it. In this study, physiochemical properties of the Chitin isolated from Plumatella repens belonging to the phylum Bryozoa was determined for the first time. The Chitin structure was also studied comparatively by isolating Chitin from an insect species ( Palomena prasina ) of the phylum Arthropoda, and Fomes fomentarius belonging to the kingdom Fungi. It was observed that the bryozoan Chitin was in the α form, as in the arthropod and fungal Chitins. The Chitin contents in the dry weight of the bryozoan, fungal and insect species were observed to be 13.3%, 2.4%, and 10.8%, respectively. The insect Chitin exhibited the highest thermal stability followed by that of the bryozoan and then the fungal Chitins. Surface morphologies reveal that the insect and bryozoan Chitins were composed of nano fibre and pore structures, whereas the fungal Chitin had no pores or fibres. The crystallinity of the insect Chitin (CrI = 84.9%) was higher than the bryozoan (CrI = 60.1%) and fungal Chitins (CrI = 58.5%).
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differentiations of Chitin content and surface morphologies of Chitins extracted from male and female grasshopper species
PLOS ONE, 2015Co-Authors: Murat Kaya, Talat Baran, Evaldas Lelesius, Radvilė Nagrockaitė, Idris Sargin, Gulsin Arslan, Betül BitimAbstract: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 – 90nm 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%.
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Comparison of physicochemical properties of Chitins isolated from an insect (Melolontha melolontha) and a crustacean species (Oniscus asellus)
Zoomorphology, 2014Co-Authors: Murat Kaya, Vykintas Baublys, Ingrida Šatkauskienė, Betül Bitim, Vaida Tubelytė, Talat BaranAbstract:The Chitin structures of two common European species belonging to Insecta ( Melolontha melolontha ) and Crustacea ( Oniscus asellus ) were isolated. The same procedure is followed for Chitin isolations for both the species. First, HCl was used for removing of minerals in the organisms, and then, the protein structure was removed by using NaOH. Chitins obtained from these two species were characterized physicochemically. Physicochemical properties of Chitins isolated from the insect and the crustacean were compared to each other. The Chitin content for dry weights of M. melolontha and O. asellus were recorded as 13–14 and 6–7 %, respectively. The results of Fourier transform infrared spectroscopy, thermogravimetric analysis and X-ray diffraction analysis were found to be more or less similar. The surface morphologies of Chitins were examined via environmental scanning electron microscopy and nanofibers, and pore structures were observed. While the Chitin nanofibers of O. asellus were adherent to each other, nanofibers of M. melolontha were non-adherent. On the other hand, the number of pores was much higher in the Chitin from M. melolontha than in the Chitin from O. asellus . Looking at the elemental analysis results, the M. melolontha Chitin was found to be more pure than the O. asellus Chitin. For this reason, M. melolontha has been considered more attractive source for Chitin than O. asellus .
Rudrapatnam N. Tharanathan - One of the best experts on this subject based on the ideXlab platform.
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Chitin - The Undisputed Biomolecule of Great Potential
Critical Reviews in Food Science and Nutrition, 2003Co-Authors: Rudrapatnam N. Tharanathan, Farooqahmed S. KitturAbstract:Of the truly abundant polysaccharides in Nature, only Chitin has yet to find utilization in large quantity. Chitin is the second most abundant natural biopolymer derived from exoskeletons of crustaceans and also from cell walls of fungi and insects. Chitin is a linear beta 1,4-linked polymer of N-acetyl-D-glucosamine (GlcNAc), whereas chitosan, a copolymer of GlcNAc (approximately 20%) and glucosamine (GlcN, 80%) residues, is a product derived from de-N-acetylation of Chitin in the presence of hot alkali. Chitosan is, in fact, a collective name representing a family of de-N-acetylated Chitins deacetylated to different degrees. Both Chitin/chitosan and their modified derivatives find extensive applications in medicine, agriculture, food, and non-food industries as well. They have emerged as a new class of physiological materials of highly sophisticated functions. Their application versatility is a great challenge to the scientific community and to industry. All these are the result of their versatile biological activity, excellent biocompatibility, and complete biodegradability in combination with low toxicity. Commercial availability of high-purity forms of Chitin/chitosan and the continuous appearance of new types of Chitin/chitosan derivatives with more and more useful and specific properties have led to an unlimited R&D efforts on this most versatile amino polysaccharide, Chitin to find new applications, which are necessary to realize its full potential. Incidentally, this too has become an environmental priority. No doubt, Chitin is surely an undisputed biomolecule of great potential.
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Chitin the undisputed biomolecule of great potential
Critical Reviews in Food Science and Nutrition, 2003Co-Authors: Rudrapatnam N. Tharanathan, Farooqahmed S. KitturAbstract:Of the truly abundant polysaccharides in Nature, only Chitin has yet to find utilization in large quantity. Chitin is the second most abundant natural biopolymer derived from exoskeletons of crustaceans and also from cell walls of fungi and insects. Chitin is a linear β1,4-linked polymer of N-acetyl-D-glucosamine (GlcNAc), whereas chitosan, a copolymer of GlcNAc (∼20%) and glulcosamine (GlcN, 80%) residues, is a product derived from de-N-acetylation of Chitin in the presence of hot alkali. Chitosan is, in fact, a collective name representing a family of de-N-acetylated Chitins deacetylated to different degrees. Both Chitin/chitosan and their modified derivatives find extensive applications in medicine, agriculture, food, and non-food industries as well. They have emerged as a new class of physiological materials of highly sophisticated functions. Their application versatility is a great challenge to the scientific community and to industry. All these are the result of their versatile biological activity, ...
Riccardo A.a. Muzzarelli - One of the best experts on this subject based on the ideXlab platform.
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Chitin-based poly(urea-urethane)s.
Journal of Biomaterials Science-polymer Edition, 2012Co-Authors: Riccardo A.a. Muzzarelli, Pierluca Ilari, Marco TomasettiAbstract:: Chitins of various origins in DMA-LiCl solution have been reacted with excess 1,6-diisocyanatohexane (three or twelve equivalents per repeating unit) for 4-20 h. The resulting solutions were exposed to water vapor for 2 days and flexible and opaque materials were produced, which upon drying yielded powders whose main characteristics were insolubility in aqueous and organic solvents, remarkable crystallinity, typical infrared spectrum, high N/C ratio (0.287), and a high degree of substitution (0.29). Under the SEM structural features reminiscent of Chitin were absent but no thermoplastic behavior was found by differential scanning calorimetry. Chitosan was similarly treated under heterogeneous conditions in anhydrous pyridine, and yielded reaction products with a lower degree of substitution (0.17). With partially hydrolysed chitosan, highly crystalline products were obtained.
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Chitin deacetylases properties and applications
Marine Drugs, 2010Co-Authors: Yong Zhao, Rodong Park, Riccardo A.a. MuzzarelliAbstract:Chitin deacetylases, occurring in marine bacteria, several fungi and a few insects, catalyze the deacetylation of Chitin, a structural biopolymer found in countless forms of marine life, fungal cell and spore walls as well as insect cuticle and peritrophic matrices. The deacetylases recognize a sequence of four GlcNAc units in the substrate, one of which undergoes deacetylation: the resulting chitosan has a more regular deacetylation pattern than a chitosan treated with hot NaOH. Nevertheless plain Chitin is a poor substrate, but glycolated, reprecipitated or depolymerized Chitins are good ones. The marine Vibrio sp. colonize the Chitin particles and decompose the Chitin thanks to the concerted action of Chitinases and deacetylases, otherwise they could not tolerate chitosan, a recognized antibacterial biopolymer. In fact, chitosan is used to prevent infections in fishes and crustaceans. Considering that Chitin deacetylases play very important roles in the biological attack and defense systems, they may find applications for the biological control of fungal plant pathogens or insect pests in agriculture and for the biocontrol of opportunistic fungal human pathogens.
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Chitins and chitosans for the repair of wounded skin nerve cartilage and bone
Carbohydrate Polymers, 2009Co-Authors: Riccardo A.a. MuzzarelliAbstract:Abstract This review provides a balanced integration of the most recent chemical, biochemical and medical information on the unique characteristics of Chitins and chitosans in the area of animal/human tissue regeneration. Hemostasis is immediately obtained after application of most of the commercial Chitin-based dressings to traumatic and surgical wounds: platelets are activated by Chitin with redundant effects and superior performances compared with known hemostatic materials. To promote angiogenesis, necessary to support physiologically ordered tissue formation, the production of the vascular endothelial growth factor is strongly up-regulated in wound healing when macrophages are activated by Chitin/chitosan. The inhibition of activation and expression of matrix metalloproteinases in primary human dermal fibroblasts by low MW chitosans prevents or solves problems caused by metalloproteinase-2 such as the hydrolysis of the basement membrane collagen IV. Experimental biocompatible wound dressings derived from Chitin are today available in the form of hydrogels, xerogels, powders, composites, films and scaffolds: the latter are easily colonized by human cells in view of the restoration of tissue defects, with the advantage of avoiding retractive scar formation. The growth of nerve tissue has been guided with Chitin tubes covalently coated with oligopeptides derived from laminin. The regeneration of cartilage is also feasible because chitosan maintains the correct morphology of chondrocytes and preserves their capacity to synthesize cell-specific extracellular matrix: chitosan scaffolds incorporating growth factors and morphogenetic proteins have been developed. Impressive advances have been made with osteogenic chitosan composites in treating bone defects, particularly with osteoblasts from mesenchymal stem cells in porous hydroxyapatite-Chitin matrices. The introduction of azido functions in chitosan has provided photo-sensitive hydrogels that crosslink in a matter of seconds, thus paving the way to cytocompatible hydrogels for surgical use as coatings, scaffolds, drug carriers and implants capable to deliver cells and growth factors. The peculiar biochemical properties of Chitins and chitosans remain unmatched by other polysaccharides.
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Susceptibility of dibutyryl Chitin and regenerated Chitin fibres to deacylation and depolymerization by lipases
Carbohydrate Polymers, 2004Co-Authors: Corrado Muzzarelli, Oriano Francescangeli, G. Tosi, Riccardo A.a. MuzzarelliAbstract:Abstract Dibutyryl Chitin obtained by esterification with butyric anhydride and regenerated Chitin obtained from dibutyryl Chitin by saponification, both in the form of wet-spun fibres and non-wovens, were examined by infrared spectrometry and X-ray diffraction spectrometry. Chitin fibres and chitosan fibres were also studied for comparison, and found to maintain the XRD spectral features of the parent Chitin and chitosan. On the opposite, DBC fibres and non-woven exhibited depressed crystallinity, the peak at 0.46–0.47 nm, typical of Chitin, being hardly detectable, while the one usually at ca. 1.00 nm was present at ca. 1.20 nm. Both DBC fibres and non-woven were highly oriented. When exposed to porcine pancreatic lipase or wheat germ lipase, the DBC fibres gained improved crystallinity with peaks at 1.14–1.18 and 0.41 nm, due to partial regain of Chitin structure as a consequence of partial enzymatic removal of butyryl groups, as confirmed by ATR-FTIR. The RC fibres exhibited broad XRD peaks at 0.96 and 0.36 nm; sharper peaks at 0.34, 0.46–0.49 and 0.96 were observed after exposure to lipases, due to removal of a disordered polymer fraction susceptible to the unspecific enzymatic depolymerization. In fact the RC fibres were found to have 8% lower degree of acetylation compared to parent Chitin, as a consequence of the alkaline regeneration treatment. In conclusion, these modified Chitins are scarcely susceptible to degradation by lipases (besides to lysozyme, as already reported in the literature); therefore their biochemical significance in wound management seems limited. They, however, appear to be the ideal textile materials for providing mechanical support to freeze-dried chitosan sponges having amply documented activity in wound healing, and for the preparation of specialty textiles.
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Chitin and Chitinases
1999Co-Authors: Pierre Jolles, Riccardo A.a. MuzzarelliAbstract:Native, industrial and fossil Chitins.- Chitin synthesis.- Biochemistry of Chitin synthase.- Chitin biosynthesis and structural organizationin vivo.- Chitin synthases in yeast and fungi.- Function of Chitin oligosaccharides in plant and animal development.- Molecular and biochemical aspects of Chitin synthesis inhibition.- Characteristics of Chitin-binding proteins from streptomycetes.- Chitinases.- Biochemistry of Chitinases.- The structure and action of Chitinases.- Classification of Chitinase modules.- Aggressive and defensive roles for Chitinases.- Chitinases in biological control.- Host-parasite interactions: elicitation of defense responses in plants with chitosan.- Inhibitors of Chitinases.- Mammalian Chitinase-like proteins.- Chitinases of human parasites and their implications as antiparasitic targets.- Analytical biochemistry and clinical significance of N-acetyl-ss-D-glucosaminidase and related enzymes.- Exogenous chitosans.- Biochemistry, histology and clinical uses of Chitins and chitosans in wound healing.- Veterinary practice with Chitin and chitosan.- Immunological aspects of Chitin and Chitin derivatives administered to animals.- Clinical and biochemical evaluation of chitosan for hypercholesterolemia and overweight control.- Microparticulate drug delivery systems.- Antimicrobial action of exogenous chitosan.