IN-VITRO UPTAKE AND INCORPORATION OF [H-3] GLUCOSAMINE AND [H-3] LEUCINE BY PLAGIORCHIS ELEGANS METACERCARIAE

We examined the ability of Plagiorchis elegans metacercariae to take u p [H-3]glucosamine and [H-3]leucine in vitro and incorporate these pre cursors into parasite tissues at various times in their development. U ptake of both precursors was greater by young metacercariae (less than or equal to 8 hr postinfection [PI]) than old metacercariae (> 8 hr P I). Virtually all. [H-3]glucosamine was incorporated into juvenile wor ms, whereas only small amounts of [H-3]leucine were incorporated into both juvenile worms and cyst walls. [H-3]glucosamine was incorporated into a variety of proteins by 2-hr- and 5-day-old metacercariae as det ermined by sodium dodecyl sulfate polyacrylamide gel electrophoresis a nd fluorography. There was evidence of developmentally regulated or st age-specific expression of 14-, 19.5-, and 37-kDa proteins by older me tacercariae. These results suggest a differential incorporation of nut rients procured from the insect host into parasite tissues by metacerc ariae of different ages over the course of their development.