Mineralized bodies in the fat body of rhinocricus padbergi (Diplopoda)

ABSTRACT

The fat body is a loosely packed tissue distributed throughout the body cavities of millipedes. The mainfunction of this tissue is the storage of lipids, glycogen, proteins and uric acid and also serves as a site forthe permanent storage for excretion products. In this work, we examined the ultrastructure of the mineralizedbodies found in the fat body of the millipede Rhinocricus padbergi. The mineralized bodies were sphericalbodies that varied in structural organization within a single cell some consisted of several concentric layers ofamorphous material while others were surrounded by a layer of electron-dense material intimately associatedwith the surrounding membrane. The histochemical and ultrastructural results suggested that these mineralizedbodies are involved in the accumulation of calcium and uric acid. The large number of these structures foundin the fat body of millipedes may be a consequence of these animals´ diet since they overturn soil rich in largeamounts and/or variety of minerals. As in other organisms, uric acid probably accumulates as the metabolicproduct of the degradation of nucleic acids derived from autophagy of the rough endoplasmic reticulum duean earlier massive protein synthesis, but may also be extracted from the hemolymph.