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

Hyrsl, Pavel | Büyükgüzel, Ender | Büyükgüzel, Kemal

Other | 2011 | Türkiye Entomoloji Dergisi35 ( 3 ) , pp.397 - 405

Eikosanoidlerin böceklerin hücresel, humoral immün savunma reaksiyonlarına ve strese karşı tepkilerine aracılık ettiği bilinmektedir. Bu aracı moleküllerin işlevi farklı eikosanoid biyosentezi inhibitörleri tarafından spesifik olarak önlenebilir. Bu inhibitörlerin böceklerde total hemolenf protein bileşimi üzerine etkileri detaylı olarak çalışılmamıştır. Eikosanoidlerin böceklerde stress faktörlerine karşı sentezlenen ve diğer savunma reaksiyonlarından sorumlu proteinler üzerinde etkili olarak fizyolojik dengenin sağlanma-sına aracılık ettiği düşünülmüştür. Bu sebeple Büyük bal mumu güvesi Galleria mellonella (Linnaeus, 1758) (Lepid . . .optera: Pyralidae) larvaları farklı etki mekanizmalarına sahip eikosanoid biyosentezi inhibitörleri eskuletin, deksametazon ve fenidonu % 0.001, 0.01, 0.1 ve 1.0 oranında içeren yapay besinler ile beslenmiştir. Larvaların eskuletin ile beslenmesi 45 kDa protein bileşiminde (belirlenen 16 protein bandından biri) uygulanan inhibitörün dozuna bağlı olarak önemli değişime sebep olmuştur. Diğer başlıca hemolenf proteinlerinden lipoforinler (ApoLP-I) ve depo proteinleri üzerinde denenen eikosanoid biyosentezi inhibitörlerinin önemli bir etkisi olmamıştır. Deksametazon ve fenidon hemolenf proteinlerinde önemli bir değişikliğe sebep olmamıştır. Bu çalışmanın sonuçları eikosanoidlerin, en azından lipoksijenaz ürünlerinin, böcek dokularında yapısal ve işlevsel olarak protein bileşimi üzerinde etkili olduğunu göstermiştir. Eikosanoid biyosentezi inhibitörlerinin doğrudan zararlı böceklerin kontrolünde kullanılması yaygın olmasa da bu çalışmadan elde edilen sonuçlar böceklerde eikosanoidlerin fizyolojik sinyal sistemlerindeki rollerinin anlaşılmasına katkıda bulunmaktadır. Eicosanoids mediate insects cellular and humoral immune reactions and stress responses. Function of these mediators can be specifically blocked using different eicosanoid biosynthesis inhibitors (EBIs). Effects of EBIs on total haemolymph protein composition have not been extensively studied in insects. We posed the hypothesis that eicosanoids also mediate physiological homeostasis by regulating protein profiles involved in stress response and other defensive reactions. To test this idea, we reared greater wax moth Galleria mellonella (Linnaeus,1758) (Lepidoptera: Pyralidae) larvae on artificial diets containing 0.001, 0.01, 0.1 or 1.0% of specific EBIs with different mode of action: Esculetin, dexamethasone and phenidone. Feeding larvae with esculetin caused significantly dose-dependent changes in 45 kDa protein fraction (one of 16 proteins detected) using sodium dodecyl-sulphate polyacrylamide gradient gel electrophoresis followed by silver staining. Other main haemolymph proteins, lipophorins (ApoLP-I) and storage proteins, were not affected by EBIs treatments. Dexamethasone and phenidone caused no significant differences in detected protein fractions. We infer from these findings that eicosanoids, at least lipoxygenase products, have been implicated in the protein composition of insect tissues as structural and functional concept. Although it has not yet been possible to use directly EBIs for insect pest control, our results bring new data to understand physiological signaling systems in insects Daha fazlası Daha az

Harmancı, Cumhur | Büyükgüzel, Kemal | Büyükgüzel, Ender

Article | 2019 | Journal of Economic Entomology112 ( 3 ) , pp.1081 - 1088

Understanding the effects of diet on metabolic events is crucial for biological control programs of parasitoid insects. As bioindicators of long-term physiological stress: survivorship of fifth instar larvae, pupation, adult survival, and developmental time for stages of endoparasitoid Pimpla turionellae L. (Hymenoptera: Ichneumonidae) were investigated by rearing the parasitoid on the host, Galleria mellonella L. (Lepidoptera: Pyralidae) pupae were treated with neomycin. First instar larvae of G. mellonella were reared on artificial diets containing 0.005, 0.01, or 0.5 g neomycin (g/100 g of diet) until seventh instar larvae; the p . . .upae from these larvae were used as a host for rearing P. turionellae. In the control group, the pupae from larvae reared on artificial diets without neomycin were used as a host. Survivorship of fifth instar, pupal, and adult stages of P. turionellae L. reared on G. mellonella pupae as a host fed with different concentrations of neomycin were significantly decreased in comparison to the control group. Approximately eighty percent of P. turionellae L. pupae were produced from control host pupae, while other neomycin concentrations significantly decreased the pupation of the parasitoid. Pimpla turionellae L. larvae reared on control host pupae reached fifth instar in about 9.6 ± 0.61 d, while the larvae reared from a host pupae exposed to the highest antibiotic concentration completed their development to the fifth instar in about 7.4 d. These results showed that neomycin, and possibly its metabolites, contaminated P. turionellae L. larvae from a host and affected larval stages of the parasitoid. © The Author(s) 2019. Published by Oxford University Press on behalf of Entomological Society of America Daha fazlası Daha az

Büyükgüzel, Kemal

Article | 2001 | JOURNAL OF ECONOMIC ENTOMOLOGY94 ( 1 ) , pp.21 - 26

Effects of novobiocin, nalidixic, and oxolinic acids on the survival and development of the hymenopterous endoparasitoid Pimpla turionellae L. were investigated alone and in various combinations by rearing larvae aseptically on chemically defined synthetic diets. Effects varied with the levels and kinds of the antibiotics in the tested combinations. Among the tested antibiotics alone, only the lowest level of novobiocin enhanced the postlarval survival. Most of the combinations significantly increased the number of survivors in the postlarval developmental stages. Novobiocin in combination with nalidixic acid (6.0:2.0 mg) in the art . . .ificial diet produced a yield of 80.8% pupae and 69.4% adults, respectively. This combination also shortened the developmental time to adult emergence. Similarly, on most of the diets with combinations of the antibiotics, the development of the larvae up to adult stage was noticeably faster than those on the control diets. An approximate to 50% reduction in the percentages of pupae and adults was recorded bs 6.0 mg of novobiocin in combination with 0.75 mg of oxolinic acid compared with the control diet. Although this combination prolonged the complete development of the insect according to other novobiocin and oxolinic acid combinations, developmental time was significantly shorter than that with control diet Daha fazlası Daha az

Büyükgüzel, Kemal

Article | 2002 | Turkish Journal of Zoology26 ( 1 ) , pp.121 - 126

Endoparazitoid bir zarkanatlı türü, Pimpla turionellae L., kimyasal yapısı bilinen sentetik besin ortamlarında aseptik şartlarda beslenerek, güçlü antibakteriyel ajanlar olan novobiyosin, nalidiksik ve oksolinik asitin böceğin yaşama ve gelişmesine ayrı ayrı etkileri inclendi. Beşinci evredeki larvaların yaşama yüzdesi antibiyotiklerin farklı miktalarını içeren besinler tarafından önemli derecede etkilenmemiştir. Novobiyosinin en düşük miktarını içeren besin pup ve ergin yüzdesini önemli derecede artırmıştır. Bu miktar aynı zamanda beşinci evreye ulaşmak için gereken süreyi kısaltmış, ancak larvaların ergin evreye kadar gelişmesi üz . . .erinde önemli bir etki yapmamıştır. Oksolinik asitin en düşük miktarı yaşama üzerinde etkili olmazken böceğin gelişmesini geçiktirmiştir. Antibiyotiklerin yüksek miktarları genellikle gelişme oranını artırmış, yaşamayı düşürmüştür. Nalidiksik asitin denenen bütün miktarları ise yaşamayı dikkate değer bir şekilde düşürmüştür. Bu sonuçlar novobiyosinin ve bir dereceye kadar oksolinik asitin denenen en düşük miktarının böceğin biyolojik kontrol amacıyla yapay ortamlarda yetiştirilmesinde kullanılan sentetik besinlere ilave edilebileceğini göstermektedir. The effects of 13 antimicrobial agents that have different structures and modes of action, on the survival and development of the hymenopterous endoparasitoid, Pimpla turionellae L., were investigated by rearing the larvae aseptically on chemically defined synthetic diets. These effects varied according to their kind and dietary levels. The agents tested exerted their effects generally during the post-larval development of the insect. The post-larval survival and development were negatively affected by most of the agents tested at certain levels. The antimicrobial agents tested also affected the larval development but had no significant effects on the larval survival of the insect. The larvae showed a wide tolerance against both the kind and dietary levels of the agents. None of the agents tested were toxic to the larvae. Sodium benzoate and nystatin at low levels had positive effects on the food consumption of the larvae Daha fazlası Daha az