Potentiation of Tentacle Ball Formation by a Trypsin-Like Protease and Accompanying Augmented Ingestion in Glutathione-Induced Feeding in Hydra

Abstract

Abstract Tentacle ball formation may be a component of sequential feeding behavior in Hydra. This behavioral response is elicited by reduced glutathione after exposure to trypsin for 5 min at concentrations ranging from 0.1 fg/ml to 1 μg/ml. Trypsin and thrombin potentiated this response more effectively than the other proteases examined. Trypsin significantly promoted the ingestion of dead, fixed shrimp attached to their tentacles in the presence of glutathione. In an actual feeding situation, a trypsin-like protease, released from living wounded prey, may potentiate tentacle ball formation, and as a result, the ingestion of prey would be promoted in co-operation with reduced glutathione. We found that an immunoreactive protein for the monoclonal antibodies J245 and J5 was reduced in size in animals treated with trypsin; >300 kDa in animals without trypsin vs. 250 kDa or 110 kDa depending on the extent of trypsin treatment. Thus, this protein that is immunoreactive with J245 and J5 is likely to be involv...