Identification of the proteome complement of hypopharyngeal glands from two strains of honeybees (Apis mellifera)

We investigated the protein complement of the hypopharyngeal gland (HG) of winter worker bees from a strain of Apis mellifera artificially selected for increased royal jelly yield and A. m. carnica winter worker bees. Proteins were partially identified using two-dimensional gel electrophoresis (2-DE). MALDI-TOF MS and protein engine identification tools that were utilized for the honeybee genome. Most identified proteins in the two bees strains were assigned to major royal jelly (RJ) proteins (MRJPs). Marked differences were found in the heterogeneity of the MRJPs, in particular MRJP3. Two of the proteins, alpha-glucosidase and glucose oxidase, were related to carbohydrate metabolism and energy. For the first time in the HG of honeybees, two proteins, peroxiredoxin and thioredoxin peroxidase, which are related to antioxidation functions, and actin 5C, a major cytoskeletal actin protein which may supply enough actin for normal function of cells, have been identified. Results suggest that the HGs serve a storage function in winter and that during the winter period the HG of high RJ producing bees store more proteins than those of Carnica bees.