Chitin Formation and Diagenesis
There are several books on properties of chitin and associated biomolecules and their biochemical significance. However, the present volume deals with a wide variety of biogeochemical and organic geochemical aspects of this vital macromolecule written by
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Chitin Nanostructures in Living Organisms Riccardo A.A. Muzzarelli
Contents 1.1 Introduction....................................................................................................................... 1.2 Biosynthesis and Characteristic Properties of Chitins...................................................... 1.2.1 Alpha-Chitin: The 3D Hydrogen Bonded Polymorph.......................................... 1.2.2 Beta-Chitin: The 2D Hydrogen Bonded Polymorph............................................ 1.3 Chitin in Insects................................................................................................................ 1.3.1 Sclerotization of the Insect Cuticles..................................................................... 1.4 Chitin in Crustaceans........................................................................................................ 1.4.1 Isolation of Crustacean Nanofibrils...................................................................... 1.5 Chitin in Chitons............................................................................................................... 1.6 Chitin in Sponges and Corals............................................................................................ 1.7 Isolation of Chitin Microfibrils from Diatoms.................................................................. 1.8 Conclusion........................................................................................................................ References..................................................................................................................................
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Abstract In living organisms, chitin synthase present in chitosomes promotes the polymerization of N-acetylglucosamine, then the native chitin is assembled into nanocrystals. The latter cluster into long chitin-protein fibers that form a planar network whose spacings are filled up with pigments, nano-sized inorganic compounds and other substances. In certain cases quinones contribute to the mechanical strength by tanning. Elaborated but robust structures are present in arthropods, chitons, yeasts, fungi, diatoms, corals and sponges. The occurrence of a chitinproducing system is an ancestral condition observable in a number of phyla. Chitin supported many organisms during the Cambrian life explosion. Current research on the chitinous nanostructures is today important in order to understand the roles of chitin in vivo, as well as to prepare materials for medical and veterinary applications, in particular composites for filling bone defects, hemostatic bandages for emergency management of bleeding, and non-wovens for the ordered regeneration of wounded tissues.
R.A.A. Muzzarelli (*) Professor Emeritus of Enzymology, University of Ancona, Ancona, Italy e-mail: [email protected] N.S. Gupta (ed.), Chitin, Topics in Geobiology 34, DOI 10.1007/978-90-481-9684-5_1, © Springer Science+Business Media B.V. 2011
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R.A.A. Muzzarelli
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