MICROARCHITECTURE AND MINERALIZATION IN LORICAE OF PHACOTACEAN FLAGELLATES

The loricae of the phacotacean genera Pteromonas, Phacotus and Dysmorp hococcus were examined by light, scanning and transmission electron mi croscopy, and analyzed by energy-dispersive X-ray spectroscopy. In gen eral, all loricae consist of a meshwork of interwoven granulo-fibrilla r components, many of which are subsequently mineralized. In Pteromona s and Phacotus, the major mineralizing element is calcium, which appea rs to be processed in the Golgi apparatus and transported to the cell surface via cytoplasmic vesicles. In contrast, in Dysmorphococcus, the major metals are iron and manganese, and there is no evidence thus fa r of active cellular involvement in their incorporation into the loric ae. With respect to morphology, the loricae of both Pteromonas and Pha cotus are bivalved, whereas the lorica of Dysmorphococcus is a single, porate unit. Lorica microarchitecture in Dysmorphococcus and Phacotus consists of granular and needle-like components, whereas the lorica o f Pteromonas is composed primarily of electron-opaque calcium-containi ng granules associated with other less-dense fibrillar material.