Regulation of A{cyrillic}M{cyrillic}R{cyrillic}-deaminase activity from white muscle of common carp Cyprinus carpio

AMP-deaminase was purified to electrophoretic homogeneity from white skeletal muscle of a teleost fish, the common carp, Cyprinus carpio. The purified enzyme was highly stable and showed non-Michaelis-Menten kinetics with a S0.5 value for AMP of 2.52 ± 0.16 mM (SEM) and a Hill coefficient of 1.19 ± 0.11. Specific activity of the purified enzyme was 1000-1200 U/mg protein. The pH optimum was 6.3 and the enzyme was activated by ADP and ATP, but inhibited by phosphate and fluoride. Low concentrations of NaCl and KCl (100-150 mM) activated, whereas higher concentrations were inhibitory. Free radicals inactivated the enzyme, decreasing Vmax by one-half but not affecting S0.5 or Hill coefficient. Possible regulatory mechanisms of AMP-deaminase activity in fish muscle are discussed

AMP-deaminase from goldfish white muscle: Regulatory properties and redistribution under exposure to high environmental oxygen level

AMP-deaminase was partially purified from white skeletal muscle of goldfish, Carassius auratus. The enzyme was highly stable, showing virtually no change in activity at 1 month following the purification process when stored in 1 M KCl at 2-4°C. The specific activity of the purified enzyme was 130-150 U/mg protein, with a pH optimum of about pH 6.5. AMP-aminohydrolase (AMPD) showed non-Michaelis-Menten kinetics, with a S0.5 (half saturation by the substrate) for AMP of 0.73 ± 0.03 mM, a Hill coefficient of 2.01 ± 0.26, and a Vmax (maximum velocity) of 176 ± 46 U/mg protein. Both sodium and potassium ions activated goldfish AMPD at low concentrations, with maximal activation at about 80 mM of each chloride salt, whereas higher concentrations became inhibitory. Magnesium and calcium ions also inhibited goldfish muscle AMPD, as did phosphate and fluoride; at a concentration of 8 mM, each anion reduced activity by about 66%. ADP and ATP were strong activators and both demonstrated concentration-dependent activation, with maximal effects at 0.5-1.5 mM. Fish exposure to a hig

The mancozeb-containing carbamate fungicide tattoo induces mild oxidative stress in goldfish brain, liver, and kidney

Tattoo belongs to the group of carbamate fungicides and contains Mancozeb (ethylene(bis)dithiocarbamate) as its main constituent. The toxicity of Mancozeb to living organisms, particularly fish, is not resolved. This work investigated the effects of 96 h of exposure to 3, 5, or 10 mg L-1 of Tattoo (corresponding to 0.9, 1.5, or 3 mg L-1 of Mancozeb) on the levels of oxidative stress markers and the antioxidant enzyme system of brain, liver, and kidney of goldfish, Carassius auratus). In liver, Tattoo exposure resulted in increased activities of superoxide dismutase (SOD) by 70%-79%, catalase by 23%-52% and glutathione peroxidase (GPx) by 49%. The content of protein carbonyls (CP) in liver was also enhanced by 92%-125% indicating extensive damage to proteins. Similar increases in CP levels (by 98%-111%) accompanied by reduced glucose-6-phosphate dehydrogenase activity (by 13%-15%) was observed in kidney of fish expose

Tissue-specific induction of oxidative stress in goldfish by 2,4-dichlorophenoxyacetic acid: Mild in brain and moderate in liver and kidney

This study investigated the effects of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) on free radical-related processes in tissues of goldfish given 96. h exposures to 1, 10 or 100. mg/L of 2,4-D as well as 96. h recovery from the 100. mg/L treatment. In liver, 2,4-D exposure increased levels of protein carbonyls and lipid peroxides by 36-53% and 24-43%, respectively, but both parameters reverted during recovery, whereas in brain glutathione status improved in response to 2,4-D. Lipid peroxide content in kidney was enhanced by 40-43% after exposure to 2,4-D with a decrease during recovery. Exposure to 2,4-D also reduced liver acetylcholinesterase activity by 31-41%. The treatment increased catalase activity in brain, but returned it to initial levels after recovery. In kidney, exposure to 100. mg/L of 2,4-D caused a 33% decrease of superoxide dismutase activity. Thus, goldfish exposure to 2,4-D induced moderate oxidative stress in liver and kidney and mild oxidative stress in brain

Acute exposure to the penconazole-containing fungicide Topas partially augments antioxidant potential in goldfish tissues

Penconazole is a systemic fungicide commonly used in agriculture as the commercial preparation Topas. Although triazole fungicides are widely found in the aquatic environment, little is known about their acute toxicity on fish. In this study we assessed the effects of short-term exposure to Topas on some parameters of homeostasis of reactive oxygen species (ROS), such as the levels of markers of oxidative stress and parameters of the antioxidant defense system of goldfish (Carassius auratus L.). Gills appeared to be the main target organ of Topas toxicity, showing the greatest number of parameters affected. Gills of Topas-treated fish showed a higher content of low (L-SH) and high (H-SH) molecular mass thiols and higher activities of superoxide dismutase (SOD), catalase, glutathione reductase (GR), glutathione-S-transferase (GST), and glucose-6-phosphate dehydrogenase (G6PDH) as well as reduced carbonyl protein content (CP), as compared with those in the contro

Effect of prometryn-containing herbicide gesagard on hematological profiles and biochemical parameters in goldfish liver and plasma

The impact of goldfish exposure for 96 h to herbicide Gesagard 500 FW at concentrations 0.2, 1, or 5 mg L−1 (corresponding to 0.1, 0.5 or 2.5 mg L-1 of effective compound prometryn) on the hematological profile of blood and biochemical parameters of plasma and liver was studied. Fish exposure to low concentration of the herbicide (0.2 mg L-1) slightly decreased liver glycogen and plasma lactate levels. Plasma glucose levels rose by 27% in goldfish exposed to 1 mg L-1 Gesagard. The activity of lactate dehydrogenase decreased by 63% and 36% in plasma of fish exposed to herbicide at concentrations 1 and 5 mg L-1, respectively, but was not affected in liver. Goldfish exposure to the highest concentration of Gesagard (5 mg L-1) decreased hematocrit by 23% and increased monocyte count by 57%, and elevated triacylglycerol level by 91% in plasma. Overall, the results indicate that acute exposure to Gesagard induced minor changes in the hematological and biochemical parameters of goldfish, suggesting that disruptions of these parameters may provide early warning signs that could be useful for assessing acute or sublethal toxic effects of pesticides on aquatic species

Oxidative stress responses in gills of goldfish, Carassius auratus, exposed to the metribuzin-containing herbicide Sencor

Metribuzin belongs to the family of asymmetrical triazine compounds and is an active ingredient in many commercial herbicides including Sencor. Effects on goldfish (Carassius auratus L.) of exposure for 96 h to 7.14, 35.7 or 71.4 mg L-1 Sencor 70 WG (corresponding to 5, 25 and 50 mg L-1 of metribuzin) were examined by evaluating oxidative stress markers and activities of antioxidant and associated enzymes in gills. Fish exposed to the lowest Sencor concentration (7.14 mg L-1) showed a 94% increase in levels of protein carbonyls in gills as well as 45% and 144% increases in the activities of glutathione peroxidase and glutathione-S-transferase. Exposure to the highest Sencor concentration (71.4 mg L-1) resulted in reduced levels of protein carbonyls by 56% and lipid peroxides by 40%, as compared with controls, but enhanced levels of low and high molecular mass thiols by 71% and 36%, respectively. The activities of superoxide dismutase, glutathione peroxidase and glutathione-S-transferase were increased in gills of goldfish exposed to 71.4 mg L-1 Sencor. At any concentration tested, Sencor did not affect the activities of glutathione reductase, glucose-6-phosphate dehydrogenase, lactate dehydrogenase or acetylcholine esterase in gills. The results of this study indicate that acute exposure of goldfish to Sencor had effect on free radical processes in gills and glutathione-dependent antioxidants effectively protect proteins and lipids from oxidation

Histopathological and biochemical changes in goldfish kidney due to exposure to the herbicide Sencor may be related to induction of oxidative stress

Molecular mechanisms of toxicity by the metribuzin-containing herbicide Sencor to living organisms, particularly fish, have not yet been extensively investigated. In the present work, we studied the effects of 96h exposure to 7.14, 35.7, or 71.4mgL-1 of Sencor (corresponding to 5, 25, or 50mgL-1 of its herbicidal component metribuzin) on goldfish (Carassius auratus L.), examining the histology, levels of oxidative stress markers, and activities of antioxidant and related enzymes in kidney as well as hematological parameters and leukocyte profiles in blood. The treatment induced various histopathological changes in goldfish kidney, such as hypertrophy of intertubular hematopoietic tissue, small and multiple hemorrhages, glomerular shrinkage, a decrease in space between glomerulus and Bowman's capsule, degeneration and necrosis of the tubular epithelium. Sencor exposure also decreased activities of selected enzymes in kidney; activities of catalase decreased by 31-34%, glutathione peroxidase by 14-33%, glutathione reductase by 17-25%, and acetylcholinesterase by 31%. However, glucose-6-phosphate dehydrogenase and lactate dehydrogenase activities increased by 25-30% and 22% in kidney after treatment with 7.14 or 35.7mgL-1 and 71.4mgL-1 Sencor, respectively. Kidney levels of protein carbonyls increased by 177% after exposure to 35.7mgL-1 of Sencor indicating extensive damage to proteins. Lipid peroxide concentrations also increased by 25% after exposure to 7.14mgL-1 of Sencor, but levels were reduced by 42% in the 71.4mgL-1 exposure group. The data indicate that induction of oxidative stress is one of the mechanisms responsible for Sencor toxicity to fish

Toxicity of environmental Gesagard to goldfish may be connected with induction of low intensity oxidative stress in concentration- and tissue-related manners

Prometryn is a selective herbicide commonly used in agriculture as the commercial preparation, Gesagard. Goldfish (Carassius auratus) exposure for 96h to 0.2, 1, or 5mgL-1 Gesagard 500FW (corresponding to 0.1, 0.5, and 2.5mgL-1 of prometryn) on indices of oxidative stress (lipid peroxides, protein carbonyls, and thiol content) and activities of antioxidant and related enzymes in gills, liver, and kidney was studied. Gills appeared to be the most resistant to Gesagard treatment, reacting to only the highest concentration of herbicide with enhanced levels of low molecular mass thiols and activities of glutathione S-transferase (GST) and glutathione reductase. Goldfish exposure to 0.2-5mgL-1 Gesagard resulted in enhancement of carbonyl protein level and activity of superoxide dismutase (SOD), but reduced the lipid peroxide (LOOH) content and activity of glutathione peroxidase in liver. Kidney appeared to be the main target organ of Gesagard toxicity, showing the greatest number of parameters affected even under low concentrations of herbicide. An increase in the content of L-SH and activity of SOD was accompanied with decreased activities of catalase, GST, and glucose-6-phosphate dehydrogenase and reduced levels of LOOH in kidney of Gesagard treated fish. The treatment also induced various histological changes in goldfish liver and kidney which could be related to their dysfunction. The present study indicates that Gesagard induced oxidative stress of differing intensities in the three goldfish tissues and demonstrated that kidney would be the best target organ to analyze, reveal, and monitor Gesagard effects on fish

Cobalt-induced oxidative stress in brain, liver and kidney of goldfish Carassius auratus

Cobalt is an essential element, but at high concentrations it is toxic. In addition to its well-known function as an integral part of cobalamin (vitamin B 12), cobalt has recently been shown to be a mimetic of hypoxia and a stimulator of the production of reactive oxygen species. The present study investigated the responses of goldfish, Carassius auratus, to 96h exposure to 50, 100 or 150mgL -1 Co 2+ in aquarium water (administered as CoCl 2). The concentrations of cobalt in aquaria did not change during fish exposure. Exposure to cobalt resulted in increased levels of lipid peroxides in brain (a 111% increase after exposure to 150mgL -1 Co 2+) and liver (30-66% increases after exposure to 50-150mgL -1 Co 2+), whereas the content of protein carbonyls rose only in kidney (by 112%) after exposure to 150mgL -1 cobalt. Low molecular mass thiols were depleted by 24-41% in brain in response to cobalt treatment. The activities of primary antioxidant enzymes, superoxide dismutase (SOD) and catalase, were substantially suppressed in brain and liver as a result of Co 2+ exposure, whereas in kidney catalase activity was unchanged and SOD activity increased. The activities of glutathione-related enzymes, glutathione peroxidase and glutathione-S-transferase, did not change as a result of cobalt exposure, but glutathione reductase activity increased by ∼40% and ∼70% in brain and kidney, respectively. Taken together, these data show that exposure of fish to Co 2+ ions results in the development of oxidative stress and the activation of defense systems in different goldfish tissues