Triangulation of methods using insect cell lines to investigate insecticidal mode‐of‐action

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, ⊍-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.

Design, synthesis and insecticidal activity and mechanism research of Chasmanthinine derivatives

“…In order to verify our supposition, we tested the cytotoxicity of Sf9 cells for all target compounds. Sf9 cells derived from S. frugiperda have been widely used as basic models of insecticide cytotoxicology to study pesticide effects due to the in vitro experiments having the advantages of high throughput and high reproducibility 18 – 21 . Therefore, MTT colorimetry was used to test the cytotoxicity of the target compounds on Sf9 cells.…”

Entomotoxic Activity of the Extracts from the Fungus, Alternaria tenuissima and Its Major Metabolite, Tenuazonic Acid

“…Testing entomotoxic substances on insect and mammalian cells is helpful for the primary determination of the mechanisms of their action on arthropods [ 68 ]. Among 65 mycotoxins tested, TeA had relatively weak cytotoxicity to both insect and mammalian cells.…”