Structure Modification Of Fenvalerate During Trichoplusia Ni(Tn)Cell Metabolism

Fenvalerate, a useful synthetic pyrethroid pesticide, is effective in controlling insect populations and has a low toxicity to mammals.Many insects developed resistance because of the long term use of fenvalerate. The long term use of fenvalerate also caused a series of environment problems. However, the resistance mechanism of insect is still in research now. Our previous research showed the contents of P450 in insect cells increased after the Trichoplusia ni(Tn) cells was treated by fenvalerate. The research of proteomics showed three isozymes of P450s were hydroxylase.Our hypothesis was that fenvalerate was hydroxylated by hydroxylase. The structural changes resulted in its derivative could not bind the receptor on Tn cell. The purpose of this research is to test if the structure of fenvalerate derivative was consistent with our prediction.First, we treated Tn cells 12h with 12.5μM/L fenvalerate. Then the fenvalerate and its derivatives were recovered and purified from the culture media by ether extraction and silica gel column chromatography. At last, the structure modifications of fenvalerate were detected by Nuclear Magnetic Resonance Apparatus, Mass Spectrometer and elemental analysis.The structure of fenvalerate derivative showed that the cyano was reduced and the phenoxyl group was substituted during the metabolizing process in Tn cells.Previous study showed insects'cytochrome P450 was an important role in the metabolism of insecticides. But our research showed that the cyano was reduced to reduce toxicity and the phenoxyl group was substituted to increase its water solubility during the metabolizing process in Tn cells. The phenoxyl group was catalyzed either by hydroxylases or by the other hydrolases. Thus, more subsequent research is required to declare the concrete mechanism of drug resistance.