Mineralizing matrices in the skeletal axes of two Corallium species (Alcyonacea).

Soluble organic matrices extracted from the axial part of the skeletons of two Corallium species (Coralliidae, Alcyonacea) were analysed using FTIR spectrometry, HPLC, IEF, 2-D gel electrophoresis and XANES. All these methods show that the main characteristics of the two matrices are similar, but not identical. Both matrices are composed of proteins and sugars; they are acidic with poorly separated molecular masses. The sugar contents are low, and the matrices do not seem highly glycosylated. The differences and similarities of these matrices are also observed in the minor element contents and in the micro- and nanostructures of the samples. These results confirm the control of the morphology and the chemical composition of calcitic biocrystals. Biomineralisation processes in Coralliidae are taxonomically significant, and differ from those of Scleractinia skeletons.