IN-VIVO RESPONSES OF HONEY-BEE MIDGUT PROTEASES TO 2 PROTEASE INHIBITORS FROM POTATO

Potato protease inhibitors, POT-1 and POT-2, were fed to newly emerged adult honey bees in cages at different doses in either sugar syrup (0 .2 or 0.01% w:v) or pollen food (1 or 0.2% w:w), In vivo activities of three digestive endopeptidases (trypsin, chymotrypsin and elastase) a nd one exopeptidase (leucine aminopeptidase; LAP) were measured after 3 or 8 days' exposure of bees to inhibitor, Enzyme activities were sig nificantly lower at day 8 than at day 3, except for elastase, which di d not change. POT-2 significantly reduced the activity of all endopept idases at both timepoints, regardless of the dose level or the medium in which the inhibitor was administered, POT-1 acted in a similar mann er, except that 0.01% POT-1 in syrup had no effect on bees. There was no consistent trend in changes in LAP activity. Bees fed either inhibi tor at 1% in pollen or at 0.2% in syrup had significantly reduced life spans, with the effect of the pollen treatment being greater than the syrup treatment. The survival of bees fed POT-1 or POT-2 at 0.2% in po llen or 0.01% in syrup did not differ from the controls. (C) 1998 Else vier Science Ltd. All rights reserved.