Hymenolepis diminuta: glucose and glycogen gradients in the adult tapeworm.

Adult (20-day-old) Hymenolepis diminuta were cut into 12 pieces of equal length, and the individual pieces of the tapeworm's strobila were analyzed. There was a continuous gradient of decreasing concentrations of glucose (mM) and decreasing levels of glycogen (microgram/mg wt) in the strobila. The ethanol extracts of the individual pieces of strobila contained four compounds tentatively identified as disaccharides; the distributions of these compounds were different from those of glucose and glycogen. The distributions of glucose, glycogen, and the "disaccharides" changed when tapeworms were incubated for 1 h in saline or glucose. When compared, on a per-weight basis, to the most posterior sections of the strobila, the anterior sections absorbed more glucose and incorporated more glucose into glycogen. There was a continuous gradient of decreasing values along the tapeworm's strobila of the Vmax for glucose uptake, while the Kt values for glucose uptake changed only slightly. The data indicate that glucose and glycogen metabolism are most active in the anterior part of the tapeworm's strobila where new proglottids are produced and the initial stages of organogenesis occur.

Preliminary biochemical characterization of faeces from uninfected rats and rats infected with the tapeworm, Hymenolepis diminuta.

Faecal pellets were collected from uninfected rats and rats infected with Hymenolepis diminuta, and analysed for caloric value, lipids, carbohydrates, glucose, amino acids, and proteins. Faeces from infected rats contained significantly more lipid and less carbohydrate and glucose than faeces from control rats. The total free amino acid content of faeces from infected and control rats did not differ, but there were significant differences in the amounts of individual free amino acids. The data support the hypothesis that the nutrient composition of faeces from infected and control hosts differ. Beetles that serve as the intermediate host for H. diminuta may be able to detect these differences, and this may explain why beetles preferentially ingest faeces containing the tapeworm s eggs.

Quantification of benzoquinones in the flour beetles. Tribolium castaneum and Tribolium confusum.

Benzoquinones were extracted from flour beetles by rinsing them for 8 min in methanol followed by homogenization in fresh methanol. This procedure recovered > 96% of the total benzoquinones from both species, with the methanolic rinse and supernatant representing the "surface" and "total" benzoquinones. As determined by UV/VIS spectrometry and reversed-phase HPLC, the methanolic rinse contained methyl- and ethyl-1,4-benzoquinone (MBQ and EBQ), but no substituted hydroquinones, The methanolic supernatant contained MBQ and EBQ, and methyl- and ethyl-hydroquinone. When stored at -20 degrees C for 72 hr, the chemical composition of the methanolic rinse did not change, but the composition of the methanolic homogenate did change. Notably, the amounts of benzoquinones in the methanolic supernatant decreased during storage. The method described represents an improvement over those described previously in that it uses less hazardous solvents for extraction (methanol vs more non-polar solvents such as hexane) and allows for the differentiation and quantification of the surface and total benzoquinones of these beetles.