EFFECT OF TUNICAMYCIN ON THE UPTAKE AND INCORPORATION OF GALACTOSE INHYMENOLEPIS-DIMINUTA

The effects of tunicamycin (TM) on the uptake and incorporation of tri tiated galactose into the tegumental membrane and carcass from adult H ymenolepis diminuta were examined to assess the potential usefulness o f this inhibitor for studying the function of the tapeworm surface gly cocalyx. Hymenolepis diminuta adults (11 days old) were preincubated f or 1 hr, pulsed for 30 min with [H-3]galactose and [C-14]leucine, and chased for 2 hr; replicate experiments were conducted in which all med ia contained no TM or TM at 10 mu g/ml. Tunicamycin significantly inhi bited the incorporation of tritiated galactose into the tapeworm's car cass and 30,000-g tegumental membrane fraction. Incorporation of triti ated galactose into the tapeworm's tegumental surface membrane also wa s inhibited significantly when expressed relative to the incorporation of [C-14]leucine. Tunicamycin did not affect the amounts of free, i.e ., soluble, [H-3]galactose or [C-14]leucine recovered from the tapewor ms nor did it affect the short-term (2 min) uptake of [H-3]galactose b y tapeworms. Thus, the inhibitory effect of TM appears to be al the le vel of protein glycosylation rather than carbohydrate (galactose) tran sport. The data indicate that TM might be useful for producing tapewor m surface membranes with diminished carbohydrate moieties.