[Frontiers in Bioscience E4, 711-720, January 1, 2012]

The crustacean cuticle: structure, composition and mineralization

Hiromichi Nagasawa1

1Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo, Tokyo 113-8657, Japan

TABLE OF CONTENTS

1. Abstract
2. Introduction
3. Physical structure of cuticle
4. Chemical composition of cuticle
5. Decomposition and formation of cuticle during molting
5.1. Endocrine regulation of molting
5.2. Temporary storage of calcium carbonate during molting
5.3. Synthesis and decomposition of chitin
6. Regulation of calcification in the cuticle and temporary storage tissues
6.1. Acidic macromolecules
6.2. Organic matrix contributing to formation of gastroliths
6.3. Organic matrix contributing to the calcification of ceca
6.4. Organic matrices responsible for amorphous calcium carbonate
7. Perspective
8. Acknowledgements
9. References

1. ABSTRACT

Crustaceans have a rigid exoskeleton, which is made of a layered cuticle, covering the soft body parts for protection from conspecific competitors and/or interspecific predators. Calcium carbonate adds rigidity to the crustacean cuticle, which consequently means that growth only occur at each molt. The current study presents a review of existing literature on crustacean exoskeleton cuticle physiology and biochemistry in relation to the molting process with special reference to calcification. As a result, research matter where knowledge remains limited has been identified during the molting process, including 1) whether the same or different epithelial cells are responsible for the decomposition and/or reconstruction of chitin and proteins, 2) how calcium carbonate levels are regulated at the cellular level during transfer between the cuticle and body organs, and 3) what factors maintain the amorphous state of calcium carbonate following deposition in the exoskeleton and temporary storage organs. The identification of these areas of focus provides a basis on which targeted future research may be developed, and potentially applied to other invertebrate or even vertebrate processes.