Response to Reduced Glutathione of Hydra Cultured in Different Places: Involvement of Protease Activities in Modulation of the Behavioral Response

Abstract

We have reported elsewhere the tentacle ball formation in Hydra japonica as its feeding response to reduced glutathione [1]. Glutathione-induced response also has been characterized by other behaviors by other workers [2,3]. The tentacle ball formation has interesting features, easy quantitative determination, and sensitive modification by many biologically active substances, including biologically active peptides, platelet proteins [4], and growth factors from mammals [5]. All these studies were done in a laboratory in Fukuoka. The same animal, however, showed a weak response when it was cultured in a different place, Otsu, located about 600 km away from Fukuoka despite the same culture method with the same prey. We became curious and so have studied why Hydra cultured in different places responds differently to glutathione. We found that short-term treatment of live animals at low concentration with chymotrypsin was enough to induce strong tentacle ball formation in response to reduced glutathione.