DEPRESSED PROTEIN AND COPPER CONTENT OF THE MIDGUT GLAND IN AN INTERMEDIATE HOST, GAMMARUS-PULEX (CRUSTACEA), INFECTED WITH CYSTACANTHS OF POMPHORHYNCHUS-LAEVIS (ACANTHOCEPHALA)

It had previously been shown that hemolymph protein titers (especially hemocyanin) in Gammarus pulex infected with the cystacanth of Pomphorhynchus laevis were significantly elevated above levels in uninfected animals (Bentley and Hurd, 1993). In this study, the protein and copper contents of midgut glands (thought to be hemopoietic tissue) were investigated to determine whether these were affected by infection. The volume of midgut glands from infected gammarids did not differ from uninfected gammarids of the same total wet weight. However, midgut glands from infected gammarids showed a significant depression in total protein concentration (52.33 mu g mm(-3) +/- 5.16 infected versus 82.23 mu g mm(-3) +/- 10.22 uninfected; P < 0.05 Chow test) and gland copper concentration (6.73 mmol mm(-3) 0.67 infected versus 10.94 mmol mm(-3) +/- 1.35 uninfected; P < 0.05, Chow test). The possibility that infection induces a shift in resources from the storage organ to the hemolymph is discussed. (C) 1995 Academic Press, Inc.