Honey Bee (Apis mellifera) Exposomes and Biological Pathways Associated with Nosema ceranae Infection

A pilot study was conducted to determine if exposome profiles of honey bees (Apis mellifera) are associated with Nosema ceranae infection and whether xenobiotic exposures effect changes in known biological pathways of bees. Thirty stationary hives were selected from seven apiaries representing urban and suburban geographies. Foraging bees were harvested during the summer of 2015 and analyzed for Nosema ceranae infection via semi-quantitative polymerase chain reaction (sq-PCR) and discovery-based exposome analysis via gas chromatography-time of flight mass spectrometry (GC-TOF). The resulting datasets were divided into case and control groups based on the prevalence of N. ceranae infection. Xenobiotic burden was determined to be associated with N. ceranae infection, and co-variate analysis determined differentially expressed biological chemicals and naturally occurring chemicals in the bee exposomes. Biological pathways analyses putatively identified 10 dysregulated pathways as well as the presence of the P450 oxidative metabolism of naphthalene for detoxification. Based on these results, it is evident that the integration of genetic disease screening with discovery-based exposomics provides a promising multi-omic platform to identify adverse biological effects to bees occurring from exposures to chemicals and parasites. In addition, this approach will generate new hypotheses for targeted follow-up studies to examine bee health.