Metabolism and ultrastructure of dormant podocysts of Chrysaora quinquecirrha (scyphozoa)

Oxygen uptake by the podocyst of the scyphozoan, Chrysaora quinquecirrha, is about one‐fourth that of the scyphistoma, based on total protein, but is nearly equal to that of the scyphistoma when calculated on the basis of total DNA. Opening the podocyst cuticle causes a two to threefold increase in oxygen consumption within the first hour. Podocysts held for 11–13 months at 25°C retain viability, even though more than half of the DNA, one‐third of the protein, and one‐fifth of the lipid are lost. Ultrastructural observations indicate that the cyst contains a population of active cells, with numbers of mitochondria and microvilli, and a mass of internal yolkfilled cells, some of which are lysed and/or phagocytized during dormancy. The active cells acquire many phagocytic vacuoles containing large particles. This may represent a unique mechanism for prolonged survival in the dormant condition.