Honey bee (Apis mellifera) exposomes and dysregulated metabolic pathways associated with Nosema ceranae infection

PLoS One. 2019 Mar 7;14(3):e0213249. doi: 10.1371/journal.pone.0213249. eCollection 2019.

Abstract

Honey bee (Apis mellifera) health has been severely impacted by multiple environmental stressors including parasitic infection, pesticide exposure, and poor nutrition. The decline in bee health is therefore a complex multifactorial problem which requires a holistic investigative approach. Within the exposome paradigm, the combined exposure to the environment, drugs, food, and individuals' internal biochemistry affects health in positive and negative ways. In the context of the exposome, honey bee hive infection with parasites such as Nosema ceranae is also a form of environmental exposure. In this study, we hypothesized that exposure to xenobiotic pesticides and other environmental chemicals increases susceptibility to N. ceranae infection upon incidental exposure to the parasite. We further queried whether these exposures could be linked to changes in conserved metabolic biological pathways. From 30 hives sampled across 10 sites, a total of 2,352 chemical features were found via gas chromatography-time of flight mass spectrometry (GC-TOF) in extracts of honey bees collected from each hive. Of these, 20 pesticides were identified and annotated, and found to be significantly associated with N. ceranae infection. We further determined that infected hives were linked to a greater number of xenobiotic exposures, and the relative concentration of the exposures were not linked to the presence of a N. ceranae infection. In the exposome profiles of the bees, we also found chemicals inherent to known biological metabolic pathways of Apis mellifera and identified 9 dysregulated pathways. These findings have led us to posit that for hives exposed to similar chemicals, those that incur multiple, simultaneous xenobiotic stressors have a greater incidence of infection with N. ceranae. Mechanistically, our results suggests the overwhelming nature of these exposures negatively affects the biological functioning of the bee, and could explain how the decline in bee populations is associated with pesticide exposures.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bees / drug effects
  • Bees / metabolism*
  • Bees / microbiology
  • Biomarkers / metabolism*
  • Environmental Exposure / adverse effects*
  • Host-Pathogen Interactions
  • Metabolic Networks and Pathways / drug effects*
  • Metabolome
  • Nosema / drug effects*
  • Nosema / physiology
  • Xenobiotics / toxicity*

Substances

  • Biomarkers
  • Xenobiotics

Grants and funding

Agilent Technologies provided financial support to HW. The Applications and Core Technology University Research grant number is 3937. The website is https://www.agilent.com/en/resources/academia/grant-funding-support. Anthony Macherone is employed by Agilent Technologies. Agilent Technologies provided support in the form of salary for author AM and financial support to HW, but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the ‘author contributions’ section.