The effects of salinity and salinity+metal (chromium and lead) exposure on atpase activity in the gill and intestine of tilapia oreochromis niloticus

PubMedID: 23114534Freshwater organisms are highly sensitive to increases in salinity because they causes serious osmoregulation problems. Salinity of inland waters can be increased as a result of anthropogenic activities. In this study, freshwater fish Oreochromis niloticus were exposed individually to increased salinities (0, 2, and 8 ppt) alone and salinity+metal [1 µg/mL chromium (Cr) or lead (Pb) exposure at 2 and 8 ppt] exposures for different time periods (1, 7, and 14 days) to investigate the response of Na+/K+-ATPase and Mg2+-ATPase in the osmoregulatory tissues (gill and intestine). Results showed that enzyme activity varied depending on salinity, tissue, metal, and exposure duration. Metal levels in controls and salinity-exposed groups were lower than the detection limit, although significant Cr and Pb accumulation occurred in the salinity+metal combination groups. In salinity-exposed groups, there were increasing trends in the enzyme activity, whereas there were decreasing trends in the metal+salinity groups. Gill ATPases were more affected by the exposure conditions compared with intestine ATPases. Results showed that salinity+metal exposure both played significant roles on ATPase activities in the osmoregulatory tissues, although the alterations in the activity were mostly insignificant supporting compensation mechanisms. Results also suggest that the osmoregulation of freshwater fish should be investigated in toxicity- monitoring programs in inland waters. © 2012 Springer Science+Business Media New York

Response of the antioxidant system of freshwater fish (Oreochromis niloticus) exposed to metals (Cd, Cu) in differing hardness [Metal (Cd, Cu) etkisindeki tatli{dotless}su bali{dotless}gi{dotless}ni{dotless}n (Oreochromis niloticus) farkli{dotless} sertlikteki sularda antioksidan sistem cevabi{dotless}]

Freshwater hardness affects metal toxicity and fish physiology. Therefore, the effects of dissolved metals on fish physiology may differ in waters from different geographic regions. In this study, toxic effects of Cd and Cu (1 mg/L) on the antioxidant system of freshwater fish Oreochromis niloticus were investigated in two different waters (commercial and tap water). Fish were exposed to metals in hard water (~320 mg CaCO3/L, conductivity 5.80 mS/cm) and soft water (~80 mg CaCO3/L, conductivity 1.77 mS/cm) for 1, 7 and 14 days and consequently the activities of antioxidant enzymes (superoxide dismutase, SOD; catalase, CAT; glutathione peroxidase, GPX; glutathione reductase, GR and glutathione S-transferase, GST) and total glutathione (GSH) levels were measured spectrophotometrically. Cu exposure of fish in soft water caused fish mortality after 8 days, though there was no fish mortality in the other conditions. The antioxidant system of fish responded differently to metal exposures in waters with differing hardness. Metal exposures in soft water showed predominant effects on the antioxidant system of fish comparing to hard water exposures. Similarly, antioxidant enzyme activities also altered in control fish depending on the hardness of waters. In general, CAT was the most sensitive antioxidant enzyme followed by SOD and GPX. CAT and GSH showed an increasing trend while a decreasing trend was observed for SOD and GPX. This study emphasized that the water chemistry affects the fish antioxidant system and metal toxicity that may be useful in environmental monitoring and also evaluating biomarkers in fish from different regions. © Published by Central Fisheries Research Institute (CFRI) Trabzon, Turkey

Gastric Histopathology, Iron Status and Iron Deficiency Anemia in Children with Helicobacter pylori Infection

Objectives: Helicobacter pylori has been established as a major cause of gastritis and peptic ulcer disease in adults and children. H. pylori infection may also have a role in the development of some extragastrointestinal diseases, including iron deficiency anemia. The aim of this study is to investigate H. pylori-related changes in gastric physiology and histology and the relationship of these changes to iron deficiency anemia in children

The effects of increased freshwater salinity in the biodisponibility of metals (Cr, Pb) and effects on antioxidant systems of Oreochromis niloticus

PubMedID: 22867965Anthropogenic activities can increase the salinity of freshwaters and this may cause stress for fish and affect metal bioavailability. Oxidative stress biomarkers are of great interest due to their responses to environmental stressors which provide valuable data for biological monitoring of aquatic pollution. Thus, the individual and combined effects of salinity and metals (Cr, Pb) were investigated in the liver of freshwater fish Oreochromis niloticus in the present study. Fish were exposed to salinity (2 and 8. ppt) alone and salinity+metal (1. µg/mL Pb and Cr) combination exposures for 0, 1, 7 and 14 days and subsequently antioxidant enzymes (superoxide dismutase, SOD; glutathione peroxidase, GPX; glutathione reductase, GR and glutathione S-transferase, GST) activities and glutathione (GSH) levels in the liver were measured. Data showed that all the parameters varied in relation to metal species, exposure durations and salinity levels. Profound alterations on the measured parameters were detected at the lower salinity compared to the higher one. Salinity increase effectively stimulated the antioxidant parameters. The effects of salinity and metals on the measured parameters increased as the exposure duration prolonged. SOD was the most affected antioxidant parameter from both salinity and metals. Because metal and salinity stresses affect fish antioxidant system, this work suggests that the chemistry of freshwaters should be taken into account in natural monitoring for metal contamination in the field. © 2012 Elsevier Inc.Çukurova ÜniversitesiA part of this study was partly supported by a grant FEF 2010YL23 from Çukurova University (Turkey)