. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 58 PAPPAS, UGLEM AND READ cose and methionine concentrations in the worms were calculated in terms of //.moles solutes/ml worm water at the end of the incubation period. Following ethanol extraction, the worms were digested in 30% KOH and the 50% ethanol precipitable carbohydrate (glycogen) was determined by the method of Dubois, Giles, Hamilton, Rebers and Smith (1956). To measure short term glucose and methionine influx rates, groups of worms were incubated in 5 ml of KRT (or the appropriate ion-substituted KRT) con- taini
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 58 PAPPAS, UGLEM AND READ cose and methionine concentrations in the worms were calculated in terms of //.moles solutes/ml worm water at the end of the incubation period. Following ethanol extraction, the worms were digested in 30% KOH and the 50% ethanol precipitable carbohydrate (glycogen) was determined by the method of Dubois, Giles, Hamilton, Rebers and Smith (1956). To measure short term glucose and methionine influx rates, groups of worms were incubated in 5 ml of KRT (or the appropriate ion-substituted KRT) con- taining /xCi/ml of D-glucose-14C(U) or L-methionine-14C(methyl) (New England Nuclear). After a 2 min incubation, the worms were removed, rinsed rapidly in 3 changes of KRT, blotted dry and extracted overnight in 2 ml of 70% ethanol. Radioactivity in 1 ml aliquots of the ethanol extracts was determined with a Nuclear-Chicago gas-flow counter. The worms were dried overnight at 95° C and weighed. 20 + 10 o CNI < 0 10. 20 40 60 Time FIGUKE 2. Percentage change in the worm water (AH^O) of Hymenolepis diminuta incubated in 5 HIM glucose in KRT, or various ion-substituted KRT solutions, versus time of incubation (min). Symbols as in Figure 1. Each point is the mean of 3 replicates. RESULTS The internal glucose concentration ([Gi]) of //. diiuhnita incubated in KRT for 60 min rose from an initial 4 imi to 12 imr, in terms of worm water. During this period, there was a net water influx representing a 5% increase in worm water, and a net decrease in worm glycogen. When incubated in 5 mM glucose in KRT for 60 min, the |Gj] rose from HIM to HIM, and was accompanied by a 20% increase in worm water; under these conditions worm glycogen increased (Figs. 1 and 2, Table I). Glucose in the incubation medium decreased from HIM to HIM during the 60 min incubation. However, of the 12 //.moles removed from the incubation medium (10 ml at //.moles/ml) by worms, only 5 //.mole
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