Comparison of the soluble organic matrices of healthy and diseased shells of Pinctada margaritifera (L.) and Pecten maximus L. (Mollusca, Bivalvia)

Pinctada margaritifera and Pecten maximus are among the mollusks of commercial value. Both are known to show abnormal calcification processes that strongly increase the mortality rate. Several parameters of the soluble organic matrices extracted from the shells of P. margaritifera and P. maximus are analyzed: bulk composition, molecular weights, and acidity. The composition of the matrices of healthy and diseased shells were compared, showing that the protein and the sugar contents are variously modified. Differences between healthy and diseased shells are dissimilar in the two species. This is in accordance with the previously described macroscopic and microscopic alterations (red color, numerous brown membranes). This study does not allow identification the origin of the disease, but provides new insights on the role of sugars in biomineralization processes.