La trame protidique des nacres

Summary

When decalcified nacre is treated with ultrasonic waves, the organic matrix resolves itself into very thin lacelike protidic leaflets, which can be studied with the electron microscope. Controls have been made showing that the lacelike structure is not an artifact due to decalcification, fixation, treatment with ultrasonic waves, dessiccation or electronic bombardment.

The ultramicroscopic structure of the lacelike mesh-work differs with the species. At this level, morphological features appear to characterize the three classes of Molluscs studied (Lamellibranchia, Gastropoda, Cephalopoda), and perhaps different genera within the same class. The extraction, by a borate buffer, of a water-soluble constituent of the protidic material does not appreciably modify the appearance of the structures studied. The extraction, by a sodium hydroxyde solution, of a second component, leaves a fibrous residue rich in alanine and glycine.