Using the honey bee (Apis mellifera L.) cell line, AmE-711, to evaluate pesticide toxicity

Authors: Goblirsch, Michael; Adamczyk, John

Submitted to: Environmental Toxicology and Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/1/2022
Publication Date: 12/16/2022
Citation: Goblirsch, M.J., Adamczyk Jr, J.J. 2022. Using the honey bee (Apis mellifera L.) cell line, AmE-711, to evaluate pesticide toxicity. Environmental Toxicology and Chemistry. https://doi.org/10.1080/00218839.2022.2146367.
DOI: https://doi.org/10.1080/00218839.2022.2146367

Interpretive Summary: Pesticides are common contaminants of landscapes where honey bees forage, as well as within the hive environment where they reside. Honey bees are not the targets of pesticide applications, but exposure during foraging or residence within the hive can have negative effects on their health and productivity. To study the effects of pesticides on honey bees, researchers often employ whole organism or whole hive experimental designs. While these approaches have proven invaluable at answering questions about the effects of pesticides at the hive level, they may not provide the precision needed to answer questions about the effects of pesticides on individual honey bee cellular and molecular processes. Here, we used the AmE-711 continuous cell line established from honey bee embryos as a model to test the toxicity of different classes of pesticides. AmE-711 cells showed a concentration-dependent loss in cell viability after acute exposure to four commercial products each containing a different class of pesticide. We observed limited loss of cell viability during long-term exposure of AmE-711 cells to sublethal concentrations of the pesticides tested. Exposure of AmE-711 cells to the half maximal lethal concentration (LC50) of each pesticide product resulted in changes in cell morphology and induction of a cellular stress gene that would support the conclusion that cells were undergoing pesticide-induced stress and death. Our study provides a foundation for additional work that addresses issues specific to honey bee toxicology at the cellular and molecular levels and complements whole organism and hive-level approaches.

Technical Abstract: Pesticides have been identified as a leading contributor to poor performance and elevated mortality of honey bee colonies in many parts of the world. Exposure of honey bees to pesticides may occur in and around treated landscapes, but also within the hive environment, where pesticide residues may accumulate. Whole organism and colony-level studies have demonstrated acute and sublethal effects of pesticides on many levels of honey bee physiology and survivorship, as well as reveal interactions with pathogens. However, there is need for in vitro studies using cell cultures to provide greater resolution of the effects of pesticides on honey bee cellular and molecular processes. Here, we used a continuous cell line established from honey bee embryonic tissues, AmE-711, in assays that enabled evaluation of pesticide exposure on honey bee cell viability. We exposed AmE-711 cells to four commercial formulations each containing a different class of pesticide. Treatment of cells with a dilution series of each formulation resulted in a concentration-dependent reduction in viability during a 24-hour exposure, while long-term exposure (120 hours) to sublethal concentrations had limited effects on viability. The acute exposure data allowed us to predict the half maximal lethal concentration (LC50) for each formulation using a four-parameter logistical model. Treatment of cells with the predicted LC50 for 12 hours induced changes to cell morphology indicative of cell stress and death. RT-qPCR analysis corroborated pesticide-induced changes in cell morphology as expression of a cellular stress response gene, l(2)efl 410087a, was increased after exposure to the predicted LC50 of each product for 18 hours. Demonstration of the effects of pesticides through use of the AmE-711 cell line provides a foundation for additional work addressing issues specific to honey bee toxicology and complements whole organism and colony-level approaches. Moreover, advancement of AmE-711 for use in high-throughput screening and in-depth metabolic and cell regulatory network analyses will promote discovery of novel control agents with decreased negative impacts for honey bees.