INORGANIC POLYPHOSPHATES IN THE DEVELOPING FRESH-WATER SPONGE EPHYDATIA-MUELLERI - EFFECT OF STRESS BY POLLUTED WATERS

Relatively high amounts of inorganic polyphosphates (approximately 55 mu g of Polyphosphate/g of wet weight) were found in the freshwater sp onge Ephydatia muelleri, particularly in the gemmules (260 mu g/g). He re we report that the polyphosphate content of this sponge changes dur ing development and in response to adverse environmental conditions. G ermination and hatching of gemmules of E. muelleri is accompanied by a strong decrease (by 94% at day 2) in polyphosphate level and a rise i n exopolyphosphatase activity. On the other hand, induction of gemmulo genesis by theophylline results in an increase (by 61%) in polyphospha te content of sponge tissue. An increase in polyphosphate content and a decrease in exopolyphosphatase activity also occur during tissue reg ression when hatched sponges are exposed to polluted water from river. Nonionic organic compounds extracted from this water were identified as contaminants causing a rise in polyphosphate content of E. muelleri . The results show that measurement of polyphosphate level may be a pr omising method to detect responses of the freshwater sponge to pollute d waters.