Movement of hexoses across the midgut of Ascaris

Sac preparations of Ascaris suum intestine were used for in vitro determinations relating to the movement of hexoses. A series of experiments were carried out to determine the effect of various gases (95% N2-5% CO2, 95% O2-5% CO2, 95% air-5% CO2, and 99+% N2) and the presence of glucose upon the movement of 3-0-methylglucose, galactose, and fructose across the worm's intestine. 3-0-methylglucose moved from the luminal fluid to the pseudocoelomic fluid at a rate of 1.29 μ moles/cm2/hr when glucose was present and 95% N2-5% CO2 was the gas phase. Little movement was observed when glucose was omitted. Movement was inhibited when gases other than 95% N2-5% CO2 were employed in the system. Similar measurements were obtained with the other sugars. The results suggest that the movement of sugars across the midgut of ascaris requires an energy source and CO2. The observations agree with what is known of the helminth's carbohydrate metabolism.