Triangulation of methods using insect cell lines to investigate insecticidal mode‐of‐action. Issue 1 (11th September 2020)

• Record Type: Journal Article
• Authors: Mak, Michelle; Beattie, Karren D; Basta, Albert; Randall, David; Chen, Zhong‐Hua; Spooner‐Hart, Robert
• Is Part Of: Pest management science. Volume 77:Issue 1(2021)
• Page Start: 492
• Page End: 501
• Publication Date: 2020-09-11
• Subjects: Spodoptera frugiperda -- Drosophila melanogaster -- microelectrode ion flux estimation -- confocal scanning laser microscopy -- spectrometry -- reactive oxygen species; Pests -- Control -- Periodicals; Pesticides -- Periodicals; 632.9
• DOI: 10.1002/ps.6046
• Languages: English
• ISSNs: 1526-498X

Abstract

Abstract: BACKGROUND: This study investigated three in vitro models to assist in elucidating possible mode‐of‐action, which could be adopted to evaluate insecticidal activity of complex, unknown, or multi‐constituent formulations. We used a combination of absorbance spectrometry, confocal scanning laser microscopy and microelectrode ion flux estimation (MIFE) to provide insight into potential target sites for insecticides. This study used two insect cell lines and evaluated three pyrethroid insecticides. RESULTS: We observed that the two cell lines produced distinctly different responses. Drosophila melanogaster D.mel‐ S2 cell line was a useful model to monitor ion flux changes, resulting from insecticides with neural toxicity; however, it was less useful to determine some metabolic pathway indicators of toxic stress. Conversely, the Spodoptera frugiperda Sf9 cell line produced acute reactive oxygen species (ROS) in response to insecticide treatments, but was not highly responsive in electrophysiological experiments. We also showed that the natural, multi‐constituent botanical extract of pyrethrum elicited different Na +, Cl − and Ca 2+ ion fluxes than its synthetic, single constituent analogues, α ‐cypermethrin and esfenvalerate. These two methods used in combination with absorbance spectrometry measuring cell growth inhibition plus cell mortality assays shed some light on cytotoxic responses in differing model cell lines. CONCLUSION: This research highlights the importance of using multiple cell types and interdisciplinary methods to provide a better insight into mode of insecticidal action. This is especially pertinent to novel biopesticide discovery, as the underlying mechanisms for toxicity in initial screening processes are likely to be unknown. Abstract : By testing known pesticides on two model insect cell lines we show a triangulation of electrophysiological studies, fluorescence microscopy and spectrophotometry is a powerful approach to elucidate multiple, unknown modes‐of‐action. © 2020 Society of Chemical Industry