CYTOCHEMISTRY OF THE LONG-NECKED CELLS IN THE FOOT OFONCHIDORIS MURICATA(NUDIBRANCHIA)

Abstract

The long-necked cells of the foot on Onchidoris muricata were found distributed among the shorter secretory cells which composed most of the epidermal tissue. The long-necked cells extend through the basement membrane on which the smaller cells lie. The ultrastructure of the cell body at the base of the cell shows the nucleus, large amounts of rough endoplasmic reticulum, and an extensive Golgi body that produces large numbers of secretory granules. The periodic acid-thiosemicarbazide-silver protein (PA-TSC-SP) test for polysaccharides was negative for the secretory material. These results are consistent with polysaccharides having large obstructing groups such as sulfates. The high iron diamine (HID) test for sulfated carbohydrates was positive in the Golgi saccules and secretory granules at the base of the cell. Tannic acid fixation for glucosaminoglycans was only slightly positive in the extracellular matrix. Alcian blue stained tissue for light microscopy complimented the ultrastructural cytochemical tests and indicated that the secretory materials are sulfated mucopolysaccharides.