SEX-SPECIFIC AND DEVELOPMENTAL STAGE-SPECIFIC GELATINOLYTIC ACTIVITY IN THE FLESHFLY NEOBELLIERIA-BULLATA AND THE REGULATING ROLE OF 20-OH-ECDYSONE

The sex- and developmental stage specific occurrence of gelatin-degrad ing enzymes has as yet never been systematically investigated in any i nsect species. By way of zymographic analysis, gelatinolytic activity was analyzed in the hemolymph and homogenates of the gray fleshfly Neo bellieria bullata. Gelatinolytic activity was detected in feeding larv ae and disappeared from both hemolymph and total body extracts during the wandering stage. An increase in gelatinolytic activity is observed around the third day after pupariation and again in lace pharate adul ts. In adult females, gelatinolytic activity is only present in the he molymph during the vitellogenic stages, whereas it is undetectable in the adult male hemolymph. Gelatinolytic activity is high in the fat bo dy of vitellogenic females but low in that of previtellogenic females and in males. Injection of 20-OH-ecdysone induces gelatinolytic activi ty in previtellogenic females and in liver-fed males. In vitro, this h ormone triggers gelatinase production by the fat body of liver-fed mal es but surprisingly not by that of sugar-fed (previtellogenic) females , which indicates that ecdysteroids are not the only regulatory molecu les involved. Our data suggest that in Neobellieria, and perhaps in ot her insects as well, gelatinolytic activity is indirectly involved in growth, metamorphosis and reproduction. (C) 1997 Elsevier Science Inc.