Arthropoda, chitin

As the major, organic, skeletal substance of invertebrates, chitin is found principally in the phyla Annelida (segmented worms), Arthropoda, and MoUusca, and, to a lesser extent, in Coelenterata and Nematoda (unsegmented worms). A critical compilation of the reported occurrences of chitin amongst these lower animals, especially the Arthropoda, has been made by Richards. This author reports that chitin has been found in the body wall... 

The most common biopolymers derived from animals are chitin and chito-san. Chitin is a macromolecule found in the shells of crabs, lobsters, shrimps, and insects. The primary unit in the chitin polymer is 2-deoxy-2-(acetylamino) glucose. Chitin can be degraded by chitinase. Chitosan is a modified natural carbohydrate polymer derived from deactylation of chitin, which occurs principally in animals of the phylum Arthropoda. Chitosan is also prepared from squid pens. Chitin is insoluble in its native form but chitosan, the partly deacetylated form, is water soluble. The materials are biocompatible and have antimicrobial activities as well as the ability to absorb heavy metal ions [16]. 

Chitin is widely distributed throughout nature, being the main structural polysaccharide that forms the characteristic exoskeleton of most of the invertebrates. High concentrations of up to 85% are found in Arthropoda (especially the edible crab), which are particularly able to synthesize chitin (Muzzarelli, 1976). 

Chitin, chitosan and derivatives. See also http //en. wikipedia.org/wiki/Chitin http //en. wikipedia.org/wiki/Chitosan http //www.3dchem.com/molecules. asp ID=444 http //directory.google.com/Top/Science/Biology/Flora and Faima/ Animalia/Arthropoda/Cmstacea/... 

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