The metabolism of glucose byHaemonchus contortus, in vitro

Abstract

AdultHaemonchus contortusobtained from freshly killed sheep were incubated in a medium similar to Tyrode's saline containing known amounts of D-[U-14C]glucose. The worms appeared to remain in a healthy condition throughout the incubations which lasted for up to 6 h. All the radioactivity was recovered either within the worms or in the incubation vessel in the form of CO2, excretory products and unmetabolized glucose. An oxygen electrode in the incubation liquid showed that, because of their rapid oxygen consumption, the worms were under anaerobic conditions during all or nearly all of the incubation period, despite the presence of oxygen in the gas phase of the vessel. In terms both of quantity and radioactivity the main excretory products in solution were propan-1-ol, propionate and acetate. Smaller amounts of ethanol, lactate and succinate were excreted. Much radioactivity was associated with the expired CO2. At the end of the incubations glucose other than the initial radioactive glucose was detected indicating that the absorption of glucose byH. contortusis complex and needs further investigation. The present experiments suggest that the rate of absorption depends on the worm's need for nutrients. The results are compared with those found for other parasitic nematodes, particularlyAscaris lumbricoides, Heterakis gallinaeandTrichuris vulpis.The importance of CO2fixation in the utilization of energy from glucose byH. contortusis discussed.