Mollusc Shell Patterning: Difference between revisions
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The mollusc shell is made up of both organic and inorganic components. The organic components are chitin, proteins with many aspartic acid residues, and silk fibroin protein(1). The inorganic component is calcium carbonate CaCO3. The calcium carbonate can crystalize into aragonite or calcite. | The mollusc shell is made up of both organic and inorganic components. The organic components are chitin, proteins with many aspartic acid residues, and silk fibroin protein(1). The inorganic component is calcium carbonate CaCO3. The calcium carbonate can crystalize into aragonite or calcite. | ||
The mollusc mantle is a sheet of epithelial cells that secrete various proteins necessary for shell formation. The mantle epithelial cells thus control the shell structure (Figure 2A)(2). The secreted proteins organize and crystalize the shell in between the periostracum (secreted by the mantle) and the mantle in a space called the extrapallial space. | |||
[[Image:Molluscfigure2.png|frame|center]] | [[Image:Molluscfigure2.png|frame|center]] | ||
Revision as of 09:58, 29 September 2015
Example Patterns
Specifications
| Theoretical | Empirical | |
|---|---|---|
| Pixel Dimension | 0.5 um X 5 um | |
| Pattern Size | 10 cm X 10 cm | |
| Accuracy | ||
| Precision |
Mechanism
The mollusc shell is made up of both organic and inorganic components. The organic components are chitin, proteins with many aspartic acid residues, and silk fibroin protein(1). The inorganic component is calcium carbonate CaCO3. The calcium carbonate can crystalize into aragonite or calcite.
The mollusc mantle is a sheet of epithelial cells that secrete various proteins necessary for shell formation. The mantle epithelial cells thus control the shell structure (Figure 2A)(2). The secreted proteins organize and crystalize the shell in between the periostracum (secreted by the mantle) and the mantle in a space called the extrapallial space.
Organic matrices made of chitin, decorated with acidic proteins, and filled with silk fibroin gel are first layed down. Nucleating proteins localized in the center of the matrix start CaCO3 crystalization. Crystalization continues upwards (towards the mantle) through the chitin layers by mineral bridges (3). Thus, several grains grow against each other towards the mantle (Figure 2B,C). Mollusc shell formation can be modeled by thermodynamically driven grain growth(4).
Reference/Resources
- T. Furuhashi, C. Schwarzinger, I. Miksik, M. Smrz, A. Beran, Molluscan shell evolution with review of shell calcification hypothesis. Comparative Biochemistry and Physiology, Part B. 154, 351–371 (2009).
- F. Heinemann, M. Launspach, K. Gries, M. Fritz, Gastropod nacre: Structure, properties and growth — Biological, chemical and physical basics. Biophysical Chemistry. 153, 126–153 (2011).
- F. Nudelman, Nacre biomineralisation: A review on the mechanisms of crystal nucleation. Seminars in Cell and Developmental Biology, 1–9 (2015).
- B. Bayerlein et al., Self-similar mesostructure evolution of the growing mollusc shell reminiscent of thermodynamically driven grain growth. Nat Mater. 13, 1102–1107 (2014).
