A VITELLOGENIN ANTIBODY IN HONEY BEES (APIS MELLIFERA) Characterization and application as potential biomarker for insecticide exposure.

The insect yolk precursor vitellogenin is a lipoglycoprotein synthesised and stored in the fat body and secreted into the hemolymph. In honey bees, vitellogenin displays crucial functions in hormone signalling, behavioural transition of nurse bees to foragers, stress resistance and longevity in workers. Plant protection products (PPPs) such as neonicotinoids, pyrethroids and organophosphate alter transcriptional expression of vitellogenin. To assess PPP-induced alterations on protein level, we developed a rabbit polyclonal vitellogenin antibody. After characterization, we assessed its specificity and vitellogenin levels in different tissues of worker bees. The vitellogenin antibody recognized full-length 180 kDa vitellogenin and the lighter fragment of 150 kDa in fat body, hemolymph and brain. In hemolymph, a band of approximately 75 kDa was detected. Subsequent mass spectrometry analysis (LC-MS/MS) confirmed the 180 and 150 kDa band as vitellogenin. Subsequently, we evaluated vitellogenin expression in brain, fat body and hemolymph upon 24 h exposure of bees to 3 ng/bee to the neonicotinoid clothianidin. Full length vitellogenin was up-regulated threefold in the fat body and the 150 kDa fragment in the brain of exposed honey bees, while no alteration occurred in the hemolymph. Up-regulation of the vitellogenin protein by the neonicotinoid clothianidin goes in line with the previously shown induction of its transcript. We conclude that vitellogenin might serve as a potential biomarker for neonicotinoid exposure in bees. This article is protected by copyright. All rights reserved.