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Öğe Antioxidative role of selenium against the toxic effect of heavy metals (Cd+2 Cr+3 on liver of rainbow trout (Oncorhynchus mykiss Walbaum 1792)(Springer, 2008) Talas, Zeliha Selamoglu; Orun, Ibrahim; Ozdemir, Ilknur; Erdogan, Kenan; Alkan, Aysel; Yilmaz, IsmetThe main purpose of this study is to discuss the effect of Cd+2, Cr+3 and Se metals on biochemical parameters in liver tissue of Oncorhynchus mykiss. The rainbow trout were exposed to heavy metal stress ( Cd+2, Cr+3) at 2 ppm dosage. The present study was undertaken to determine the protective effect of selenium treatment at the same dosage ( 2 ppm) on some biochemical parameters. The activity of catalase ( CAT), glutathione peroxidase ( GSH-Px), superoxide dismutase ( SOD) and the changes in levels of malondialdehyde ( MDA) from biochemical parameters were determined in liver tissue of the fish groups exposed to heavy metals, especially for the selenium-applied groups. Results of this study showed that the activities of CAT, GSH-Px and SOD in the tissues of fish exposed to the stress of Cd+2 and Cr+3 were significantly lower than the control groups ( P < 0.05). Meanwhile, the closer values to the control groups were obtained in selenium-added groups ( Cr+3 + Se+4, Cd+2 + Se+4). For the level of MDA, the last production of lipid peroxidation showed increases ( P < 0.05) in the groups exposed to the metal stress, whereas significant decreases were obtained in selenium-applied groups. The result of the statistical evaluation showed that the negative effects occurring in the biochemical parameters of the applied groups exposed to the toxicity of heavy metal were significantly eliminated ( P < 0.05) as a result of selenium treatment.Öğe Antioxidative role of selenium on some tissues of (Cd2+, Cr3+)-induced rainbow trout(Academic Press Inc Elsevier Science, 2008) Orun, Ibrahim; Talas, Zeliha Selamoglu; Ozdemir, IlKnur; Alkan, Aysel; Erdogan, KenanChemical toxic pollutants (especially heavy metals) are important sources of reactive oxygen species (ROS) in biological systems. Membrane phospholipids of aerobic organisms are continually subjected to oxidant challenges from endogenous and exogenous sources, while peroxidized membranes and lipid peroxidation products represent constant threats to aerobic cells. The primary antioxidant protection against free radical and ROS is provided by the enzymes glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and catalase (CAT), respectively. The trace element selenium has been implicated in chemo-prevention and drug-resistance through reduction of oxidative stress. Selenium could prevent damage to the unsaturated fatty acid Of subcellular membranes by lipid peroxidation induced by free radicals. The results reported here show that sodium selenite has an important contribution to antioxidative defense for the spleen and heart of rainbow trout. The ability of sodium selenite to prevent the oxidative stress induced by heavy metals (Cd2+, Cr3+) in fish was rationalized. (C) 2007 Elsevier Inc. All rights reserved.Öğe Bazı ağır metal ve selenyum bileşiklerine maruz kalan alabalıklarda antioksidan enzim aktivitelerinin incelenmesi(İnönü Üniversitesi, 2005) Alkan, AyselÖZET Yüksek Lisans Tezi BAZI AĞIR METAL ve SELENYUM BİLEŞİKLERİNE MARUZ KALAN ALABALIKLARDA ANTİOKSİDAN ENZİM AKTİVİTELERİNİN İNCELENMESİ Aysel ALKAN İnönü Üniversitesi Fen Bilimleri Enstitüsü Biyoloji Anabilim Dalı 55 + ix sayfa 2005 Danışman: Yrd.Doç.Dr. İbrahim ÖRÜN Bu çalışmada, selenyumun balıklarda antioksidatif rolünü belirlemek amacıyla krom, kadmiyum ve selenyumun gökkuşağı alabalığının (Oncorhynchus mykiss Walbaum,1792) karaciğer ve solungaç dokularındaki bazı biyokimyasal parametreler üzerine etkileri araştırılmıştır. Cd (2 ppm), Cr (2 ppm), Se (2 ppm), Cd+Se (2 ppm Cd + 2 ppm Se) ve Cr+Se (2 ppm Cr + 2 ppm Se)'a bir hafta süreyle maruz bırakılan gökkuşağı alabalıklarının karaciğer ve solungaç dokularında selenyum bağımlı Glutatyon peroksidaz (Se-GSHPx), Süperoksit dismutaz (SOD) ve Katalaz aktiviteleri ile malondialdehit (MDA) düzeyindeki değişimler incelenmiştir. Çalışma sonucunda Cd, Cr, Cd+Se ve Cr+Se'a maruz kalmış grupların enzim aktivitelerinde kontrole göre istatistiksel açıdan önemli oranda düşüşlerin olduğu (p<0.05) gözlenmiştir. Ayrıca Cd, Cr, Cd+Se ve Cr+Se'a maruz kalmış grupların MDA düzeylerinde kontrole göre istatistiksel olarak önemli artışların olduğu (p<0.05) belirlenmiştir. Se maruzatı ise enzim aktiviteleri ile MDA düzeylerinde önemli değişimler yaratmamıştır. Bu sonuçlar, ağır metallere maruz bırakılmış grupların biyokimyasal parametrelerinde meydana gelen olumsuz etkilerin, Se ilavesi ile giderilebileceğini ortaya koymaktadır. ANAHTAR KELİMELER: Kadmiyum (Cd), Krom (Cr), Selenyum (Se), Oksidatif stres, Antioksidan savunma sistemiÖğe MODULATING EFFECT OF SELENIUM ON GILLS OF FISH EXPOSED TO HEAVY METALS(Parlar Scientific Publications (P S P), 2011) Orun, Ibrahim; Talas, Zeliha Selamoglu; Alkan, AyselThe present study was performed to understand the preventive effect of selenium (Se4+) on heavy metal stress induced by Cd2+ and Cr3+ in rainbow trout. Changes in glutathione peroxidase (GSH-Px), catalase (CAT) and superoxide dismutase (SOD) activity, and in malondialdehyde (MDA) level in gill tissue of rainbow trout after 7 days of exposure to Cd2+ and Cr3+ were investigated in the presence and absence of Se4+. Heavy metals treated groups exhibited significant decreases (P<0.05) in GSH-Px, CAT, SOD activities of gill, and an increase (P<0.05) in MDA levels, compared to the control. In the presence of Se4+, GSH-Px activity and SOD activity were found to be higher and MDA levels were lower compared with in its absence. In the light of our findings, it could be stated that Cd2+ and Cr3+ lead to dramatic changes in biochemical parameters and selenium caused these parameters to converge to control levels when it was administered concurrently with these heavy metals. Selenium fully or partially restored enzyme activities. Lipid peroxidation was also decreased in selenium treated groups.
