SEM image showing the layer build-up of a large granule frm Molpadia.
The bioinorganic
fraction of the
dermal granules of Molpadia intermedia from a wide variety of habitats
has been
studied by chemical analysis, electron microscopy, X-ray diffraction,
thermal
analysis, visible and infrared spectroscopy and magnetic
susceptibility. It was
found to have many similarities to polynuclear iron(III) proteins.
Silica was
found to be an integral component of the granules. The proportions of
the major
elements, P and Si, were found to vary with habitat as well as the
minor
elements, Ca and Mg, whereas the Fe content remained relatively
constant.
Models are proposed for the microstructure of the granules and the
processes of
their growth.