Adamski, Zbigniew | Marciniak, Pawel | Ziemnicki, Kazimierz | Büyükgüzel, Ender | Erdem, Meltem | Büyükgüzel, Kemal | Ventrella, Emanuela

Article | 2014 | ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY87 ( 1 ) , pp.26 - 39

Plants synthesize a broad range of secondary metabolites that act as natural defenses against plant pathogens and herbivores. Among these, potato plants produce glycoalkaloids (GAs). In this study, we analyzed the effects of the dried extract of fresh potato leaves (EPL) on the biological parameters of the lepidopteran, Galleria mellonella (L.) and compared its activity to one of the main EPL components, the GA alpha-solanine. Wax moth larvae were reared from first instar on a diet supplemented with three concentrations of EPL or alpha-solanine. Both EPL and alpha-solanine affected survivorship, fecundity, and fertility of G. mellon . . .ella to approximately the same extent. We evaluated the effect of EPL and alpha-solanine on oxidative stress in midgut and fat body by measuring malondialdehyde (MDA) and protein carbonyl (PCO) contents, both biomarkers of oxidative damage. We evaluated glutathione S-transferase (GST) activity, a detoxifying enzyme acting in prevention of oxidative damage. EPL and alpha-solanine altered MDA and PCO concentrations and GST activity in fat body and midgut. We infer that the influence of EPL on G. mellonella is not enhanced by synergistic effects of the totality of potato leaf components compared to alpha-solanine alone. (C) 2014 Wiley Periodicals, Inc Daha fazlası Daha az

Tunaz, Hasan | Park, Youngjin | Büyükgüzel, Kemal | Bedick, Job C. | Aliza, A.R. Nor | Stanley, David W.

Article | 2003 | ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY52 ( 1 ) , pp.1 - 6

Intracellular phospholipase A(2) (PLA(2)) is responsible for releasing arachidonic acid from cellular phospholipids, and is thought to be the first step in eicosanoid biosynthesis. Intracellular PLA(2)s have been characterized in fat body and hemocytes from tobacco hornworms, Manduco sexta. here we show that bacterial challenge stimulated increased PLA(2) activity in isolated hemocyte preparations, relative to control hemocyte preparations that were challenged with water. The increased activity was detected as early as 15 s post-challenge and lasted for at least 1 h. The increased activity depended on a minimum bacterial challenge d . . .ose, and was inhibited in reactions conducted in the presence of oleyoxyethylphosphorylcholine, a site-specific PLA(2) inhibitor. In independent experiments with serum prepared from whole hemolymph, we found no PLA(2) activity was secreted into serum during the first 24 h following bacterial infection. We infer that a hemocytic intracellular PLA(2) activity is increased immediately an infection is detected. The significance of this enzyme lies in its role in launching the biosynthesis of eicosanoids, which mediate cellular immune reactions to bacterial infection Daha fazlası Daha az