Ecologically appropriate xenobiotics induce cytochrome P450s in Apis Mellifera

Reed M. Johnson, Wenfu Mao, Henry S. Pollock, Guodong Niu, Mary A. Schuler, May R. Berenbaum

Research output: Contribution to journalArticle

Abstract

Background: Honey bees are exposed to phytochemicals through the nectar, pollen and propolis consumed to sustain the colony. They may also encounter mycotoxins produced by Aspergillus fungi infesting pollen in beebread. Moreover, bees are exposed to agricultural pesticides, particularly in-hive acaricides used against the parasite Varroa destructor. They cope with these and other xenobiotics primarily through enzymatic detoxificative processes, but the regulation of detoxificative enzymes in honey bees remains largely unexplored. Methodology/Principal Findings: We used several approaches to ascertain effects of dietary toxins on bee susceptibility to synthetic and natural xenobiotics, including the acaricide tau-fluvalinate, the agricultural pesticide imidacloprid, and the naturally occurring mycotoxin aflatoxin. We administered potential inducers of cytochrome P450 enzymes, the principal biochemical system for Phase 1 detoxification in insects, to investigate how detoxification is regulated. The drug phenobarbital induces P450s in many insects, yet feeding bees with phenobarbital had no effect on the toxicity of tau-fluvalinate, a pesticide known to be detoxified by bee P450s. Similarly, no P450 induction, as measured by tau-fluvalinate tolerance, occurred in bees fed xanthotoxin, salicylic acid, or indole-3-carbinol, all of which induce P450s in other insects. Only quercetin, a common pollen and honey constituent, reduced tau-fluvalinate toxicity. In microarray comparisons no change in detoxificative gene expression was detected in phenobarbital-treated bees. However, northern blot analyses of guts of bees fed extracts of honey, pollen and propolis showed elevated expression of three CYP6AS P450 genes. Diet did not influence tau-fluvalinate or imidacloprid toxicity in bioassays; however, aflatoxin toxicity was higher in bees consuming sucrose or high-fructose corn syrup than in bees consuming honey. Conclusions/Significance: These results suggest that regulation of honey bee P450s is tuned to chemicals occurring naturally in the hive environment and that, in terms of toxicological capacity, a diet of sugar is not equivalent to a diet of honey.

Original languageEnglish (US)
Article numbere31051
JournalPloS one
Volume7
Issue number2
DOIs
StatePublished - Feb 3 2012

Fingerprint

Bees
Xenobiotics
Cytochromes
xenobiotics
cytochromes
Apis mellifera
fluvalinate
Apoidea
Propolis
Toxicity
Honey
Phenobarbital
Nutrition
Pesticides
Acaricides
Detoxification
Aflatoxins
phenobarbital
Mycotoxins
honey bees

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Agricultural and Biological Sciences(all)
  • General

Cite this

Ecologically appropriate xenobiotics induce cytochrome P450s in Apis Mellifera. / Johnson, Reed M.; Mao, Wenfu; Pollock, Henry S.; Niu, Guodong; Schuler, Mary A.; Berenbaum, May R.

In: PloS one, Vol. 7, No. 2, e31051, 03.02.2012.

Research output: Contribution to journalArticle

Johnson, Reed M. ; Mao, Wenfu ; Pollock, Henry S. ; Niu, Guodong ; Schuler, Mary A. ; Berenbaum, May R. / Ecologically appropriate xenobiotics induce cytochrome P450s in Apis Mellifera. In: PloS one. 2012 ; Vol. 7, No. 2.
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