Shell Layers of the Black-Lip Pearl Oyster Pinctada Margaritifera: Matching Microstructure and Composition

Comp Biochem Physiol B Biochem Mol Biol. 2011 Jul;159(3):131-9. doi: 10.1016/j.cbpb.2011.03.001. Epub 2011 Mar 22.


The nacre-prism transition of the mollusc shell Pinctada margaritifera was studied using scanning electron microscopy, electron probe micro-analysis (EPMA) and time-of-flight secondary ion mass spectrometry (TOF-SIMS). Mineralogical change is correlated with a change in organic matrix. Previous analyses had shown that sugars were involved in the transition layer (fibrous aragonite). The new Energy Dispersive Spectrometry (EDS) and TOF-SIMS maps show that the modifications at the layer boundary are complex, and that proteins and lipids are also involved. Detailed TOF-SIMS maps show that the thick organic envelopes surrounding the prisms, and between the prisms and the fibrous aragonitic layer, are not composed by regular layers, but are a patchwork of various molecules. The amino acid compositions of the nacreous and prismatic layer are compared thanks to the TOF-SIMS localized analyses.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acids / chemistry
  • Animals
  • Calcium Carbonate / chemistry*
  • Microscopy, Electron, Scanning
  • Pinctada*
  • Spectrometry, Mass, Secondary Ion


  • Amino Acids
  • Calcium Carbonate