Developmental changes in gene expression and enzyme activities of anabolic and catabolic enzymes for storage carbohydrates in the honeybee, Apis mellifera

Glycogen and trehalose are important sources of energy in insects. The expression of genes encoding the key metabolic enzymes-glycogen synthase (GS), glycogen phosphorylase (GP), trehalose-6-phosphate synthase (TPS-1), soluble trehalase (Tre-1) and membrane-bound trehalase (Tre-2)-was analyzed in 12 developmental stages of Apis mellifera worker brood. The content of GS and GP proteins, TPS activity, total trehalase activity, and the activity of Tre-1 and Tre-2 were determined. Transcript quantity was not always correlated with the content of the encoded GS or GP protein. The correlation was higher for GS (r = 0.797) than GP (r = 0.651). The expression of the glycogen synthase gene (gs) and the glycogen phosphorylase gene (gp) was high in 4- and 7-day-old larvae and in pupae, excluding the last pupal stage. The expression of the tps-1 gene was highest in the mid-pupal stage and contributed to higher enzyme activity in that stage. The expression of the tre-1 gene was higher than the expression of the tre-2 gene throughout development. In newly hatched workers, the expression of genes encoding catabolic enzymes of both carbohydrates, gp and tre-1, was higher than the expression of genes encoding anabolic enzymes. The results of this study suggest that sugar metabolism genes have somewhat different control mechanisms during larval development and metamorphosis.

[The enzymes of carbohydrates metabolism from Cysttidicola farionis (Cystidicolidae)]

The content of glycogen, glucose and trehalose was measured in larvae and adults of Cystidicola farionis, the parasite isolated from the swim bladder of Osmerus eperlanus from Vistula Lagoon. Activity of glycogen phosphorylase, alpha-amylase, glucoamylase, maltase, trehalase, and trehalose phosphorylase were measured. The highest activity was recorded for alpha-amylase 10.07 +/- 0.97 mu/mg and 7.47 +/- 0.24 mu/mg, next maltase 1.34 +/- 0.63 micromol/mg and 2.06 +/- 1.65 micronol/mg respectively for larvae and adults. The activity of glucoamylase was nearly the same for adults and larvae (about 0.20 micromol/mg). The trehalase activity was higher at adults (0.49 +/- 0.42 micromol/mg) than at larvae (0.18 +/- 0.12 micromol/mg). The activity of glycogen phosphorylase was much higher at larvae (3.58 +/- 1.49 micromol/mg) than at adults parasite (0.10 +/- 0.02 micromol/mg). The trehalose phosphorylase was present in both stages of parasite, but its activity was low. The content of glycogen and glucose was two-times higher in the adults' body than in larvae.

[The concentration of trehalose and acitvity of trehalase from Galleria mellonella larvae infected by Steinernema affinis, Bovien 1937 (Nematoda: Rhabditida: Steinernematidae)]

The experimental studies were conducted on caterpillars of wax moth Galleria mellonella infected with Steinernema affinis larvae. The concentration of trehalose and the activity of trehalase were measured during the invasion lasting 48h. The level of trehalose and activity of enzyme were slightly lower in infected insects in comparison to the control animals.