CRISPR/Cas9 mediated ryanodine receptor I4790M knockin confers unequal resistance to diamides in Plutella xylostella.

Monitoring and mechanisms of insecticide resistance in Spodoptera exigua (Lepidoptera: Noctuidae), with special reference to diamides.

Monitoring the resistance and baseline susceptibility of Plutella xylostella (L.) (Lepidoptera: Plutellidae) against spinetoram in Tamil Nadu, India

Functional validation of key cytochrome P450 monooxygenase and UDP-glycosyltransferase genes conferring cyantraniliprole resistance in Aphis gossypii Glover.

Background Plutella xylostella L. is the major pest of crucifers globally, causing significant yield loss. Aphis craccivora Koch is the main sucking pest of legumes that transmit viral diseases, leading to economic yield reduction. To minimize loss due to pests, farmers/growers use synthetic insecticides frequently for their control, which led to insecticide resistance, detrimental to natural enemies of pest, environment, etc. Therefore, in this study, the insecticidal activity of plant extract, fractions, and pure steroidal saponins from Trillium govanianum was evaluated for their bio-efficacy against targeted pests. Results Parent extract was found more effective (LC50 = 1541.2 mg L-1 ) against larvae of P. xylostella after 96 h than n-butanol, n-hexane, and ethyl acetate fractions (LC50 = 3030, 3578 and 3878.1 mg L-1 , respectively). For A. craccivora, ethyl acetate fraction (LC50 = 2186.3 mg L-1 ) was most effective after 96 h than n-hexane fraction (LC50 = 2234.6 mg L-1 ), n-butanol fraction (LC50 = 2696.3 mg L-1 ) and parent extract (LC50 = 3709.1 mg L-1 ). Among pure molecules, govanoside B was found more effective (76% mortality, LC50 = 3279.5 mg L-1 ) followed by borassoside E (74%, LC50 = 3467.1 mg L-1 ) against A. craccivora after 96 h. Conclusion Parent extract/fractions of T. govanianum showed promising efficacy against larvae of P. xylostella and A. craccivora. Further, field study is required for its bio-efficacy against targeted pests for validation and formulation development.

Insecticidal activity of the extract, fractions, and pure steroidal saponins of Trillium govanianum Wall. ex D. Don for the control of diamondback moth (Plutella xylostella L.) and aphid (Aphis craccivora Koch).

Ryanodine receptor mutations (G4946E and I4790K) differentially responsible for diamide insecticide resistance in diamondback moth, Plutella xylostella L.

Seizures are induced when subjects are exposed to severe hypoxia. It is followed by ventilatory fall-off and eventual respiratory arrest, which may underlie the pathophysiology of death in patients with epilepsy and severe respiratory disorders. However, the mechanisms of hypoxia-induced seizures have not been fully understood. Because astrocytes are involved in various neurological disorders, we aimed to investigate whether astrocytes are operational in seizure generation and respiratory arrest in a severe hypoxic condition. We examined the effects of astrocytic activation blockade on responses of EEG and ventilation to severe hypoxia. Adult mice were divided into two groups; in one group (n = 24) only vehicle was injected, and in the other group (n = 24) arundic acid, an inhibitory modulator of astrocytic activation, was administered before initiation of recording. After recording EEG and ventilation by whole body plethysmography in room air, the gas in the recording chamber was switched to 5% oxygen (nitrogen balanced) until a seizure and ventilatory depression occurred, followed by prompt switch back to room air. Severe hypoxia initially increased ventilation, followed by a seizure and ventilatory suppression in all mice examined. Fourteen mice without arundic acid showed respiratory arrest during loading of hypoxia. However, 22 mice pretreated with arundic acid did not suffer from respiratory arrest. Time from the onset of hypoxia to the occurrence of seizures was significantly longer in the group with arundic acid than that in the group without arundic acid. We suggest that blockade of astrocytic activation delays the occurrence of seizures and prevents respiratory arrest.

Makoto Uchiyama

Papers

Ryanodine receptor mutations (G4946E and I4790K) differentially responsible for diamide insecticide resistance in diamondback moth, Plutella xylostella L.

Blockade of astrocytic activation delays the occurrence of severe hypoxia-induced seizure and respiratory arrest in mice.