TRANSPORT OF SUGARS IN THE TAPEWORM CALLIOBOTHRIUM VERTICILLATUM

¹ Marine Biological Laboratory, Woods Hole, Massachusetts, 02543
² Department of Biology, Rice University, Houston, Texas 77001

1. Gas phase had no significant effect on glucose absorption or accumulation by Calliobothrium.

2. Optimum temperature for glucose accumulation is about 20° C.

3. Glucose transport was affected by pH, highest rates being observed at 8 to 9. This corresponds to the pH measured in that part of the spiral intestine inhabited by the strobilate worm.

4. Those sugars or glycosides which inhibited transport of glucose also stimulated efflux. Inhibitions produced by phlorizin, ouabain, galactose, maltose, and -methylglucoside were found to be competitive in 2 min incubations.

5. The rate of glucose transport was a function of Na⁺ in the external medium. Tissue Na⁺ increased and K⁺ decreased during glucose absorption.

6. Ouabain caused a net influx of Na⁺ and this effect was attributed to the observed inhibition of Na⁺ efflux.

7. Galactose was also accumulated by the worm but a negligible amount was incorporated in polysaccharide. Mannose, fructose, and 3-0-methylglucoside were not transported.

8. The data are discussed in terms of the specificity of the glucose transport mechanism. It is hypothesized that ouabain may inhibit two processes involved in glucose transport and accumulation.