Effect and Mechanism of Lepista nuda Mycelia Obtained via In Vitro Culture on the Lifespan of Drosophila melanogaster

Abstract

To provide a theoretical basis for biogenic fly-killing pesticides, in this study, we sought to examine the lethal effects of Lepista nuda mycelium-supplemented diets in Drosophila melanogaster. In doing so, we also studied the effects of Lepista nuda mycelium-supplemented diets on lifespan, antioxidant enzyme activity, peroxide content, relative transcript amounts of antioxidant enzyme genes, signaling pathways, and lifespan. Lower Lepista nuda mycelium-supplemented diets activated the antioxidant system and prolonged lifespan, while higher mycelium-supplemented diets had a significant toxic effect. After the administration of mycelium-supplemented diets for 24 h, the highest corrected mortality (41.96%) and lifespan inhibition rates (96.50%) were observed. In addition, the antioxidant enzyme activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px); the relative transcript amounts of the key antioxidant enzyme genes SOD, CAT, and TrxR-1; and the lifespan genes Hep and Nrf2 were found to be the lowest, while the contents of the oxidation products malondialdehyde (MDA), protein carbonylation product (PCO), and triglyceride (TG); the relative transcript amounts of the signaling pathway-related genes S6K, TOR, and Keap-1; and the lifespan gene MTH were observed to be the highest after 48 h. Higher Lepista nuda mycelium-supplemented diets significantly inhibited lifespan, acting via the initiation of oxidative stress systems.