Effects Of Water-borne Copper Research Articles

Effects of waterborne copper on oxidative stress and immune responses in red seabream, Pagrus major

Copper (Cu) plays an essential role in many enzymatic processes including cellular respiration. In this study, we investigated the oxidative stress and immunity of red seabream, Pagrus major, exposed to different concentrations of Cu2+ (10, 20, 30, and 40 μg/L) for 120 h. We measured the expressions of mRNA, activities of antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT), the levels of plasma hydrogen peroxide (H2O2) and lipid peroxide (LPO), and immune parameters lysozyme, immunoglobulin M (IgM), and melatonin. The mRNA expressions, activities of antioxidant enzymes, and the levels of plasma H2O2 and LPO were significantly higher after exposure to 30 and 40 μg/L of Cu2+ than after exposure to lower concentrations (0, 10, and 20 μg/L). However, the levels of plasma lysozyme, IgM, and melatonin were significantly lower after exposure to 30 and 40 μg/L of Cu2+. These results indicate that Cu2+ concentrations of 30 and 40 μg/L can induce an acute toxic oxidative stress and decrease the immune response in red seabream in aquarium conditions.

Effects of water-borne copper and lead on metabolic and excretion rate of bahaii loach (Turcinoemacheilus bahaii)

Beyond the role of anthropogenic activities, natural sources of metal contaminations are still controversial, together counting, however, as a major threat to inland and coastal waters, becoming an even more prominent stressor for aquatic life. To address the effects of metals on the physiological response of fish, standard metabolic rate (SMR), maximum metabolic rate (MMR), aerobic scope (AS) and factorial aerobic scope (FAS) as well as specific rate of ammonia excretion (Jamm) of Turcinoemacheilus bahaii were determined following different water-borne Cu2+ and Pb2+ treatments. Following LC50-96 h determination, 72 fish (BW = 1.153 ± 0.56 g and TL = 6.155 ± 0.97 cm) were exposed to different amounts of Cu2+ and Pb2+ in 9 different treatments (eight fish/treatment), including 0.910 mg l−1 Cu2+ for 24 h, 0.455 mg l−1 Cu2+ for 7d, 0.182 mg l−1 Cu2+ for 14d and 0.091 mg l−1 Cu2+ for 30 d as well as 124.430 mg l−1 Pb2+ for 24 h, 62.215 mg l−1 Pb2+ for 7d,12.443 mg l−1 Pb2+ for 14d, 6.221 mg l−1 Pb2+ for 30d and control. The SMR of fish was reduced following exposures to all Cu2+ and Pb2+ treatments (P < 0.05), except for 30d exposure as compared with the control. The MMR remained steady following all Cu2+ treatments while it was raised significantly (P < 0.05) following Pb2+ treatments at 7, 14 and 30d exposure. Although the AS showed a similar pattern to MMR, the FAS was elevated (P < 0.05) following all the treatments when compared with control. Lower Jamm were observed following all metals-treated fish in comparison with control (P < 0.05). In addition, higher (P < 0.05) levels of injuries were observed following all Cu2+ and Pb2+ treatments in gills and kidneys. The results suggest that Cu2+ and Pb2+ over the experimental period could impair the metabolic and excretory capacities, hence affecting the possible physiological performance of fish.

Effects of waterborne copper on toxicity stress and apoptosis responses in red seabream, Pagrus major

There has been an increasing trend of copper (Cu)-based aquaculture industry in the world, and it is necessary to evaluate the effect of copper ion exposure on water pollution. This study was aim to determine the critical concentration of toxic copper in adult red sea bream. Therefore, we investigated the effects of Cu toxicity on physiological stress and apoptosis exposed to various concentrations (10, 20, 30, and 40 μg/L). We measured physiological stress-related (corticotrophin- releasing hormone, adrenocorticotropic hormone, cortisol, and glucose), other toxic stress-related (metallothionein and Na+/K+-ATPase), and apoptosis-related (caspase-3 and hydrogen peroxide) parameters. In addition, we confirmed apoptosis. Physiological parameters were significantly increased from Cu concentration of 30 μg/L or more. However, no significant differences were observed after exposures at 10 and 20 μg/L. In addition, apoptotic cells were detected after exposure to 30 μg/L. The results of this study indicate that high concentrations induce stress and apoptosis compared to normal conditions.

MRNA Expression and activity of ion‐transporting proteins in gills of the blue crab Callinectes sapidus: Effects of waterborne copper

Waterborne Cu effects on the transcription of genes encoding ion-transporting proteins and the activities of these proteins were evaluated in gills of the blue crab Callinectes sapidus acclimated to diluted (2‰) and full (30‰) seawater. Crabs were exposed (96 h) to an environmentally relevant concentration of dissolved Cu (0.78 µM) and had their posterior (osmoregulating) gills dissected for enzymatic and molecular analysis. Endpoints analyzed were the activity of key enzymes involved in crab osmoregulation (sodium-potassium adenosine triphosphatase [Na(+)/K(+)-ATPase], hydrogen adenosine triphosphatase [H(+)-ATPase], and carbonic anhydrase [CA]) and the mRNA expression of genes encoding these enzymes and the sodium-potassium-chloride (Na(+)/K(+)/2Cl⁻) cotransporter. Copper effects were observed only in crabs acclimated to diluted seawater (hyperosmoregulating crabs) and were associated with an inhibition of the expression of mRNA of genes encoding the Na(+)/K(+)-ATPase and the Na(+)/K(+)/2Cl⁻ cotransporter. However, Cu did not affect Na(+)/K(+)-ATPase activity, indicating that the gene transcription is downregulated before a significant inhibition of the enzyme activity can be observed. This also suggests the existence of a compensatory response of this enzyme to prevent osmoregulatory disturbances after short-term exposure to environmentally relevant Cu concentrations. These findings suggest that Cu is a potential ionoregulatory toxicant in blue crabs C. sapidus acclimated to low salinity. The lack of Cu effect on blue crabs acclimated to full seawater would be due to the reduced ion uptake needed for the regulation of the hemolymph osmotic concentration in full seawater (30‰). Also, this could be explained considering the lower bioavailability of toxic Cu (free ion) associated with the higher ionic content and dissolved organic matter concentration in high salinity (30‰) than in diluted seawater (2‰).

Effects of Water-Borne Copper on Digestive and Metabolic Enzymes of the Giant Freshwater Prawn Macrobrachium rosenbergii

The aim of the present study was to evaluate the potential utility of enzyme parameters as indicators of water-borne copper (Cu(2+)) contamination in the giant freshwater prawn Macrobrachium rosenbergii. Activities of the digestive enzymes of tryptase, pepsin, cellulase, amylase, and metabolic enzymes of alkaline phosphatase (AKP), acid phosphatase (ACP), superoxide dismutase (SOD) and glutathione-S-transferase (GST) were measured in the hepatopancreas of M. rosenbergii after 7 days of exposure to copper (Cu(2+)) concentrations ranging from 0.01 mg/L to 0.5 mg/L. A significant inhibition on the digestive enzymes by Cu(2+) was observed, being relevant to the elevated Cu(2+) concentration. The maximum inhibition rate was recorded in amylase among all the digestive enzymes. As regards the metabolic enzymes, although the activity of SOD had an increase in final copper treatment groups when comparing to the controls, those of ACP and AKP significantly decreased in accordance with increase in Cu(2+) concentrations. In addition, though there was a significantly decreased GST activity in group treated with 0.01 mg/L Cu(2+); the activity could increase gradually in the prawns when exposed to higher Cu(2+) concentrations. The responses of the metabolic and digestive enzymes in the hepatopancreas of M. rosenbergii were sensitive to water-borne copper contamination; furthermore, amylase, and GST seem to be most suitable biomarkers of environmental Cu(2+) stress in M. rosenbergii.

Effects of Water-borne Copper on the Y-organ and Content of 20-hydroxyecdysone in Eriocheir sinensis

The effects of water-borne copper (Cu2+) (0.01, 0.10, 1.00, and 5.00 mg/L) on Y-organ (YO) microstructure and ultrastructure and on the content of 20-hydroxyecdysone (20-HE) in Eriocheir sinensis were studied using single gradient factor experiments. Results demonstrated that there was no significant difference in YO microstructure and ultrastructure when E. sinensis was exposed to 0.01, 0.10, and 1.00 mg/L water-borne Cu2+. However, exposure to 5.00 mg/L Cu2+ caused serious damage to the YO microstructure, with an obvious decrease in hemocoel and the disappearance of the basement membrane between cell fibers. In addition, there was an intumescence of cells around the hemocoel, the cell nucleus became enlarged or even rounded, and some cells around the hemocoel crumpled with only the cell nucleus isolated or even huddled in the hemocoel. Similarly, effects of water-borne Cu2+ on the YO ultrastructure were observed: obvious enlargement and rounding of the cell nucleus, high heterochromatinization of the nucleus chromatin, disappearance of the YO cell membrane in some severely damaged cells, and varied damage in cellular organelles, such as the disappearance of cristae in mitochondria and disruption of the nucleus membrane. The hemocyte nucleus showed considerable heterochromatinization. In addition, when the Cu2+ concentration increased, the content of 20-hydroxyecdysone (20-HE) decreased in all Cu2+ treatment groups (P < 0.05). Results of this study indicate that high water-borne Cu2+ concentration impaired the basic structure of YO, which is regarded as the secretion site of 20-HE, and hence decreased the content of 20-HE in hemolymph. Therefore, molting frequency as well as the growth of E. sinensis is inhibited when exposed to high concentrations of water-borne Cu2+.

Effects of water-borne copper on metallothionein and lipid peroxidation in the marine amphipod gammarus locusta

The aim of the current work was to determine over 10 days the effects of water-borne exposure of the marine amphipod Gammarus locusta to 4 μgCu l−1 on the metallothionein (MT; measured by differential pulse polarography) protection system and lipid peroxidation (LP; thiobarbituric acid-reactive malondialdehyde equivalents) as a measure of oxidative damage. MT levels in exposed animals increased significantly at day 2 (36% > control; P<0.001) and remained high at days 6 and 10 (55 and 38%, respectively, P<0.001). The maximum level of MT at day 6 coincided with the highest Cu body-burden. LP increased within 1 day of exposure, indicative of Cu as an oxidative stressor. However, in contrast to MT, the highest LP level was seen at day 4 (68% > control, P<0.001) before returning to control values by day 6, indicating a protective role of MT against the pro-oxidant effects of Cu.

Effects of water-borne copper on branchial chloride cells and Na +/K +-ATPase activities in Mozambique tilapia ( Oreochromis mossambicus)

Freshwater tilapia ( Oreochromis mossambicus) were exposed for different periods up to 28 days to 3.2 μM of water-borne Cu. Electron microscopical analysis of the gills demonstrated significant changes in the structure and number of chloride cells (CCs) from Cu-exposed fish when compared to controls. These cells, which are the main location of the Na +/K +-ATPase of the gills and which play a crucial role in transepithlial Na + transport, showed a time-related increase of degeneration by apoptosis and necrosis in the Cu-exposed fish. After 28 days of Cu exposure, apoptotic CCs had doubled in number while necrotic CCs had even increased by a factor of ten. The activity of the gill Na +/K +-ATPase and the plasma Na + concentration decreased in time and in parallel. An inverse relationship between the Na +/K +-ATPase specific activity and the branchial Cu content further supports the notion that this enzyme is very sensitive to Cu 2+ inhibition. In contrast to controls, no significant correlation was found in the Cu-exposed fish between the opercular CC number and the gill Na +/K +-ATPase total activities, despite the large increase in number of these cells. This study provides further evidence that not only the number but also the quality of the CCs, may determine to a large extent the branchial capacity of a freshwater fish to absorb Na + from the surrounding water.

Effects of Waterborne Copper, Cyanide, Ammonia, and Nitrite on Stress Parameters and Changes in Susceptibility to Saprolegniosis in Rainbow Trout (Oncorhynchus mykiss)

The effects of toxic exposures on the susceptibility of rainbow trout (Oncorhynchus mykiss) to saprolegniosis were evaluated. Fish were exposed to sublethal concentrations of copper (0.25 mg/liter), cyanide (0.07 mg/liter), ammonia (0.5 mg/liter), and nitrite (0.24 mg/liter) for 24 h. After exposure, the fish were challenged by Saprolegnia parasitica (3.6 x 10(sup6) zoospores per liter) for 10 min. Cortisol and cholesterol were used to indicate stress response. Similar increases of cortisol were found for the four tested chemicals. All fish with cortisol levels higher than 370 ng/ml developed the disease, while only 24% of the fish with cortisol levels lower than 370 ng/ml were infected. Cholesterol levels remained unchanged after toxic exposure. Increased susceptibilities to the pathogen were observed for ammonia (71%), copper (57%), nitrite (50%), and cyanide (33%). The increases in susceptibility as a result of cyanide and nitrite exposure could be explained by the stress response. For copper and ammonia, the combination of two different effects, the stress response and specific impairments of the defense mechanism of trout against saprolegniosis, should be considered.

Effects of water-borne copper and lead on the peripheral blood in the rosy barb,Barbus (Puntius) conchonius Hamilton

The Pb-induced abnormalities of hematopoiesis are primarily confined to the erythrocytes the leucocytes and platelets do not appear to be altered during chronic exposure. Pb effects in fishes show responses similar to those in mammals. The absence of erythrocyte {delta}-ALAD inhibition in fish exposed to Cd, Cu, Zn, and Hg indicated that this enzyme is quite specific for Pb. The objective of this work was to examine the effects of chronically sublethal concentrations of Cu and Pb on the peripheral blood parameters in the rosy barb, Barbus (Puntius) conchonius, a widely distributed freshwater bony fish.

Effects of waterborne copper or zinc on the osmoregulatory response of bluegill to a hypertonic NaCl challenge

Abstract 1. Bluegill (Lepomis macrochirus) were exposed to copper (0.77 mg/1) or zinc (2.35 mg/1) for 7 days after which they were challenged by being placed in a 250 mM NaCl solution. 2. Non-metal exposed controls started to die in the NaCl after 8 hr but those that had been exposed to copper survived at least 22 hr and some survived for at least 3 days. Zinc exposure also caused better survival in the hypertonic NaCl but not to the same extent. 3. Blood plasma osmolality, chloride, and protein, as well as the hematocrit, muscle and liver water, and gill Na-K-activated ATPase were determined in fish before and after 8 hr in the NaCl. 4. Metal exposure alone produced no significant effects on the variables measured except for a decline in plasma chloride in zinc-exposed fish. 5. Both copper- and zinc-exposed fish exhibited less of an increase in chloride upon being challenged with the NaCl than did controls. Osmolality showed a similar effect from copper but not from zinc exposure. Metal exposure produced no other differences. 6. All fish exhibited an elevated hematocrit but no change in plasma protein or tissue water when challenged. The elevated hematocrit is probably a non-specific stress response. The other data are consistent with the hypothesis that there was an influx of salt but little if any efflux of water while in the hypertonic NaCl. 7. The data suggest indirectly that copper, and to a much lesser extent zinc, seemed to reduce the permeability of the gills to an influx of chloride in this stenohaline species.