X-RAY-DIFFRACTION AND MULTINUCLEAR SOLID-STATE NMR-STUDIES OF HEPATOPANCREAL GRANULES FROM HELIX-ASPERSA AND CARCINUS-MAENAS

Granules isolated from the snail Helix aspersa and the shore crab Carc inus maenas have been studied by using scanning electron microscopy, p owder X-ray diffraction and solid-state nuclear magnetic resonance (NM R). These amorphous deposits are largely based on pyrophosphate (P2O74 -) and orthophosphate (PO43-) respectively. NMR indicates that water i s evenly distributed throughout the pyrophosphate granules and that th e PO43- ions occupy distorted lattice sites. The H-1 NMR spectra of th e orthophosphate granules of desiccated and normal deposits indicate t hat water can move in and out of these solids. This movement is probab ly facilitated by the organic component, identified by H-1-C-13 NMR, p articularly in the crab granules. The distorted lattice, the presence of hydrated ions and the interactions with the organic matrix probably account for many of the properties of these solids and are relevant t o the interpretation of their biological significance.