IN-SITU POTENTIATION OF THE GLUTATHIONE-BINDING PROTEIN FOR THE TENTACLE BALL FORMATION BY A PROTEASE AND EFFICIENT INGESTION OF PREY IN HYDRA

Within minutes, brief treatment with trypsin potentiated tentacle ball formation in Hydra japonica, a new behavioral response to reduced glu tathione. With the potentiation of this behavioral response, new gluta thione-binding proteins were immediately detected after the trypsin tr eatment of live Hydra, indicating that trypsin activated the glutathio ne-binding protein in situ. Fixed brine shrimp (Artemia francisca) wer e more efficiently ingested in the presence of trypsin and S-methylglu tathione (GSM) than in the presence of GSM alone, suggesting a biologi cal role of this behavioral potentiation by trypsin in the feeding cha in of Hydra. Ingestion of live A. francisca was significantly reduced in the presence of soybean trypsin inhibitor, suggesting that a protea se, possibly released from the wounded prey, plays a role in the feedi ng in vivo. As for Hydra swallowing its captured prey, a small hydra h ead piece was isolated and measured as it crept along a thin nylon lin e; advancement. of the head was the same in the presence of both GSM a lone, and in that of GSM and trypsin together. Together, these results indicate that the chemoreceptor potentiated in situ by a trypsin-like protease specifically evokes tentacle ball formation resulting in an efficient transfer of prey on the tentacle to the mouth. (C) 1998 Else vier Science Inc.