engleski

Interakcije insekticida s adipokinetičkim hormonima vrste Tribolium castaneum

Alternative control of insect pests plays an important role in modern pest management and helps to reduce the amount of classical pesticides deployed. Recently, it has been shown that insect endocrine system could be used as a potential target for pest control. Insect stress neurohormones seem to be especially suitable for these because stress conditions like starvation, injury, poisoning, infection, intensive locomotion etc. impose a heavy metabolic stress, and the requirements of animals in these situations are essentially similar. Insect metabolism is predominantly controlled by adipokinetic hormone (AKH) peptide family. AKHs are small peptides, from 8 to 10 amino acids long which are synthesized by neurosecretory cells of the corpora cardiaca (CC). The effects of AKHs include also stimulation of heart, locomotor and immune system. They are considered to be potentially suitable for the pest control ; by increasing of general metabolism they accelerate rate of exchange of metabolites including toxins which may result to intensification of their effect. In the present study, two insecticides were used to elicit stress in insect body and to study their interactions with the hormonal system: organophosphate pirimiphos-methyl and pyrethroid deltamethrin. For this type of research the beetle Tribolium castaneum is especially suitable. It is important insect pest species widely used for toxicological studies and it possesses two well characterized AKH peptides - Pyrap-AKH and Trica-AKH. However, the best advantageous of the T. castaneum model is knowledge of its genome which enables relatively easy application of molecular biology techniques including the RNAi technique with the gene silencing effect. The main aim of the present study was to investigate the role of AKH in stress conditions after the insecticide treatment, and to determine effect of the hormone on the insecticidal efficacy. For the experiments, beetles with different amount of AKHs present in their body (AKH-deficient, normal and AKH- over expressed) were used. AKH-deficient beetles were prepared using RNA interference technology, and AKH-over expressed beetles by ectopic Pyrap-AKH application. As needed, the beetles were treated with two insecticides (organophosphate and pyrethroid), and their mortality during 24 hours was monitored.

Tribolium castaneum, insecticides, adipokinetic hormones, RNAi technology, mortality

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