Participation of hemocyte proteinase in dissociation of the fat body on pupation of Sarcophaga peregrina (flesh fly)

In holometabolous insects, larval tissues are degraded on pupation. Previously, we established an in vitro system in which Sarcophaga fat body dissociates in the presence of pupal hemocytes, mimicking the situation in vivo (Kutata et al., J. Insect Physiol. 35, 559-565, 1989). In this paper, we showed that chymostatin and phenylmethylsulfonyl fluoride prevented dissociation of fat body in this system. Moreover, of the various proteinases tested, only chymotrypsin degraded the fat body in vitro. These results suggested that a chymotrypsin-like proteinase of hemocytes participates in dissociation of the fat body at the early pupal stage.