The Role of Eicosanoids on Nodulation Reactions to Bacterium Serratia marcescens in Larvae of Ostrinia nubilalis

Authors: HASAN TUNAZ, ALİ ARDA IŞIKBER, MEHMET KUBİLAY ER

Abstract: Nodulation is the first step of the cellular defense reactions to bacterial infections in insects. In the present study, injecting larvae of the European corn borer, Ostrinia nubilalis, with eicosanoid biosynthesis inhibitors, immediately prior to intrahemocoelic injections of the bacterium, Serratia marcescens, sharply reduced the nodulation response to bacterial challenges. Separate treatments with specific inhibitors including dexamethasone (a phospholipase A_2 inhibitor), indomethacin (a cyclooxygenase inhibitor) and phenidone (a dual cyclooxgenase/lipoxygenase inhibitor) also impaired the ability of European corn borers to form nodules in reaction to bacterial challenges. The inhibitory influence of phenidone was apparent within 30 mins after infection, and nodulation was significantly reduced, relative to the control insects, over following 4 h. These findings support the hypothesis that eicosanoids act in nodulation reactions to bacterial infections in European corn borers.

Keywords: Insect cellular immunity; nodulation; Ostrinia nubilalis

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