SDS-PAGE-Based Quantitative Assay of Hemolymph Proteins in Honeybees: Progress and Prospects for Field Application

Abstract: In human and veterinary medicine, serum proteins are considered useful biomarkers for assessing the health and nutritional status of the organism. Honeybee hemolymph has a unique proteome which could represent a source of valuable biomarkers. Therefore, the aims of this study were to separate and identify the most abundant proteins in the hemolymph of worker honeybees, to suggest a panel of these proteins which could represent useful biomarkers for assessing the nutritional and health status of the colonies and finally to analyse them in different period of the year. Four apiaries were selected in the province of Bologna and bees analysed in April, May, July, and November. Thirty specimens from three hives of each apiary were sampled and their hemolymph collected. The most represented bands obtained after 1D-SDS-PAGE were cut from the gel, and the proteins were identified using an LC-ESI-Q-MS/MS System. A total of 12 proteins were unmistakably identified; the two most abundant proteins were apolipophorin and vitellogenin, which are known biomarkers of bee trophic and health status. Two other proteins identified were transferrin and hexamerin 70a, the first being involved in iron homeostasis, and the second as a storage protein. Most of these proteins showed an increase from April to November mirroring the physiological changes of honeybees during the productive season. The current study suggested a panel of biomarkers from honeybee hemolymph worth testing under different physiological and pathological field conditions.