Büyükgüzel, Ender | Erdem, meltem | Tunaz, Hasan | Küçük, Ceyhun | Atılgan, Utku Can | Stanley, David | Büyükgüzel, Kemal

Article | 2017 | Comparative Biochemistry and Physiology -Part A : Molecular and Integrative Physiology204 , pp.121 - 128

We posed the hypothesis that inhibition of eicosanoid biosynthesis leads to increased lipid peroxidation in insects. Here we report that rearing the greater wax moth, Galleria mellonella, on media supplemented with selected inhibitors of eicosanoid biosynthesis throughout the larval, pupal and adult life led to major alterations in selected oxidative and antioxidative parameters of wax moth and its ectoparasitoid, Bracon hebetor. The highest dietary dexamethasone (Dex), esculetin (Esc) and phenidone (Phe) led to increased malondialdehyde (MDA) levels and to elevated catalase (CAT) and glutathione-S-transferase (GST) activities in al . . .l developmental stages of host larvae. Dietary Phe resulted in increased MDA levels, and CAT activity in G. mellonella adults by about 4-fold and about 2-fold, respectively. The Phe effect on GST activity in all stages of the wax moth was expressed in a dose-dependent manner, increased to 140 nmol/mg protein/min in larvae. MDA levels were increased by over 30-fold in adult wasps reared on Dex- and Esc-treated hosts. CAT and GST activities were increased in adult parasitoids reared on Esc-and Phe-treated hosts. GST activity of Dex-treated parasitoid larvae increased from about 4 to over 30 nmol/mg protein/min. Dietary Phe led to increased GST activity, by about 25-fold, in adult wasps. These data indicate that chronic inhibition of eicosanoid biosynthesis leads to increased oxidative stress, strongly supporting our hypothesis. The significance of this work lies in understanding the roles of eicosanoids in insect biology. Aside from other well-known eicosanoids actions, we propose that eicosanoids mediate reductions in oxidative stress. © 2016 Elsevier Inc Daha fazlası Daha az

Erdem, Meltem | Büyükgüzel, Ender

Article | 2015 | Archives of Insect Biochemistry and Physiology89 ( 4 ) , pp.193 - 203

The effects of a dietary plant allelochemical, xanthotoxin (XA), on survivorship, development, male and female adult longevity, fecundity, and hatchability of the greater wax moth Galleria mellonella L. were investigated. Oxidative stress indicators, the lipid peroxidation product, malondialdehyde (MDA), and protein oxidation products, protein carbonyl (PCO) contents, and activities of a detoxification enzyme glutathione S-transferase (GST) activity were determined in wax moth adults. The insect was reared from first-instar larvae on an artificial diets containing XA at 0.001, 0.005, or 0.1% to adult stage in laboratory conditions. . . .Relative to the controls, the diets containing XA concentrations led to decreased survivorship in seventh instar, pupal, and adult stages. Compared to control diet (77.7%), the highest dietary XA concentration decreased survivorship to adulthood to 11.0%. The highest XA concentration (0.1%) reduced female longevity from 10.4 to 5.7 days and decreased egg numbers from 95.0 to 33.5 and hatchability from 82.7 to 35.6%. The lowest XA concentration (0.001%) led to about a sixfold increase in MDA content. XA at high concentrations (0.005 and 0.1%) increased MDA (by threefold) and protein carbonyl (by twofold) contents decreased GST activity. The highest dietary XA concentration decreased GST activity from 0.28 ± 0.025 to 0.16 ± 0.005 µmol/mg protein/min. We infer from these findings that XA-induced oxidative stress led to decreased biological fitness. © 2015 Wiley Periodicals, Inc Daha fazlası Daha az