Proton-ATPase was localized to mitochondria-rich cells in the interlamellar region of the gills o... more Proton-ATPase was localized to mitochondria-rich cells in the interlamellar region of the gills of the elasmobranch, Squalus acanthias. Localization was accomplished using a polyclonal antibody specific for the 70 kDa subunit of the (V-type) proton-ATPase as confirmed by Western blot analysis. In addition, significant levels of N-ethymaleimide sensitive ATPase activity (0.116 +/- 0.026 mumol Pi.mg-1 protein.h-1) were also measured in crude gill membrane preparations. These data provide, for the first time, direct evidence of the localization of elements possibly involved in branchial acid-base (or ionic) regulation in elasmobranchs.
Transactions of the American Fisheries Society, 1994
Abstract In this study, we examined the ammonia and urea excretion rates in four species of fish ... more Abstract In this study, we examined the ammonia and urea excretion rates in four species of fish native to Pyramid Lake, Nevada (pH 9.4): tui chub Gila bicolor, Tahoe sucker Catostomus tahoensis, Lahontan cutthroat trout Oncorhynchus clarki henshawi, and cui-ui ...
Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology, 1998
ABSTRACT Exposure of fish to alkaline conditions clearly inhibits the rate of ammonia excretion (... more ABSTRACT Exposure of fish to alkaline conditions clearly inhibits the rate of ammonia excretion (JAMM) leading to problems of ammonia accumulation and toxicity. There is some evidence that higher environmental calcium levels may ameliorate the negative effects of alkaline exposure. In the present study, we investigated the effects of elevated environmental calcium on the recovery of ammonia excretion during acute (6 h) and chronic (15 day) exposures to high pH (pH 10), and the levels of nitrogenous products (ammonia, urea, and glutamine) in tissues and plasma (1–15 days). Acclimation to alkaline conditions results in a chronically depressed ammonia excretion rate. Glutamine as well as urea do not appear to be important in ammonia detoxification and storage. Calculations of the production rates from storage and excretion data indicate a reduction in the rate of ammonia production. Elevating environmental calcium during acute exposure to alkaline conditions does not affect the recovery of JAMM but may reduce stress. We conclude that rainbow trout survive alkaline exposure by reducing ammonia production and that the role of calcium may be in the amelioration of the stress of alkaline exposure.
Precocious sexual maturation in salmonid parr occurs under both wild and culture conditions. We i... more Precocious sexual maturation in salmonid parr occurs under both wild and culture conditions. We investigated the possibility of repeat maturation in precocious chinook salmon parr from the Nicola River, British Columbia. Precocious and immature (control) yearling parr were reared in fresh water from March 1990 to mid-June, and then transferred to salt water (29–30 ppt) until September 1990. The precocious parr were significantly larger than the controls from March to July and there were no differences in relative growth rate between the groups throughout the study. Total mortalities were 45.7 and 5.9% for precocious and control fish, respectively. All of the precocious, but none of the control fish, produced milt in March in fresh water. None of the fish produced milt soon after the transfer to salt water in June, but all precocious fish and 18.8% of the controls produced milt in September. There were no significant differences in the average plasma concentrations of Na+, Cl−, and c...
The distribution of branchial carbonic anhydrase (CA) in the shark, Squalus acanthias, was studie... more The distribution of branchial carbonic anhydrase (CA) in the shark, Squalus acanthias, was studied using in situ measurements of pH disequilibrium states in post-branchial saline, and immunological techniques, immunofluorescence microscopy and Western analysis, employing rabbit polyclonal antibodies against rat pulmonary membrane associated CA IV and chick retinal cytosolic CA II. In the in situ saline perfused gill preparation, the CA inhibitor acetazolamide produced a pH disequilibium (0.063 ± 0.022 pH units) while control and bovine carbonic anhydrase perfusions did not (0.012 ± 0.017 and 0.023 ± 0.018 pH units, respectively). These results indicate that the HCO − 3 dehydration reaction is accelerate by endogenous extracellular CA. Western analysis of saline perfused gill membrane preparations revealed an immunoreactive 48 kDa band with the CA IV probe. In crude gill homogenates, a 33 kDa and 31 kDa pair of bands is identified by the CA II probe. The pattern of immunolabeling for CA II in the gill epithelium was either diffuse or punctate within both lamellar and filament epithelial cells while eyrthrocytes and pillar cells displayed a diffuse staining pattern.
RAPID COMMUNICATION / COMMUNICATION RAPIDE Graham D. Sherwood, Jennifer Kovecses, Alice Hontela, ... more RAPID COMMUNICATION / COMMUNICATION RAPIDE Graham D. Sherwood, Jennifer Kovecses, Alice Hontela, and Joseph B. Rasmussen Simplified food webs lead to energetic bottlenecks in polluted lakes ... ARTICLES / ARTICLES Peder A. Jansen, Henning Slettvold, Anders G. Finstad, and Arnfinn Langeland Niche segregation between Arctic char (Salvelinus alpinus) and brown trout (Salmo trutta): an experimental study of mechanisms ... Franck Cattanéo, Nicolas Lamouroux, Pascal Breil, and Hervé Capra The influence of hydrological and biotic ...
The present work evaluated several aspects of the generalized stress response [endocrine (cortiso... more The present work evaluated several aspects of the generalized stress response [endocrine (cortisol), metabolic (glucose), hematologic (hematocrit and hemoglobin) and cellular (HSP70)] in the Amazonian warm-water fish matrinxã (Brycon amazonicus ) subjected to an acute cold shock. This species farming has been done in South America, and growth and feed conversion rates have been interesting. However, in subtropical areas of Brazil, where the water temperature can rapidly change, high rates of matrinxã mortality have been associated with abrupt decrease in the water temperature. Thus, we subjected matrinxã to a sudden cold shock by transferring the fish directly to tanks in which the water temperature was 10ºC below the initial conditions (cold shock from 28ºC to 18ºC). After 1h the fish were returned to the original tanks (28ºC). The handling associated with tank transfer was also imposed on control groups (not exposed to cold shock). While exposure to cold shock did not alter the me...
The Lahontan cutthroat trout lives under highly alkaline and saline conditions in Pyramid Lake, N... more The Lahontan cutthroat trout lives under highly alkaline and saline conditions in Pyramid Lake, Nevada (pH 9•4; 0•2 mmol l 1 Ca + + ; 7•3 mmol l 1 Mg + +). These experiments were conducted to study the possible roles of water Ca + + and Mg + + concentrations on ammonia excretion in the Lahontan cutthroat trout under highly alkaline conditions. The basic protocol of the experiments was to determine ammonia excretion rates during the following three exposure periods (each of 3-h duration) in sequence: (a) in normal lake water; (b) in soft lake water with the divalent cation concentrations reduced; and (c) in the soft lake water with either Ca + + or Mg + + (or no divalent cations added) added back at the appropriate lake water concentration. The soft-water exposure caused a significant reduction in ammonia excretion to about half of the control (original lake water) levels. When either Ca + + or Mg + + was added to the soft water in the third exposure period, the ammonia excretion rates were increased more than twofold back to lake water levels.
Desiccation of Pyramid Lake, Nevada, has led to continued increases in the lake's alkalinity ... more Desiccation of Pyramid Lake, Nevada, has led to continued increases in the lake's alkalinity (currently pH 9.4) that may threaten the resident Lahontan cutthroat trout population. In this study, Lahontan cutthroat trout were challenged with more alkaline water (pH 10). The objectives were to describe physiological responses which may permit survival or lead to death in future potential environmental conditions and to cast further light on the mechanisms of nitrogenous waste excretion, acid-base regulation and ionoregulation in this unusual salmonid. Ammonia excretion (Jamm) was reduced by 50 % in the first few hours, but had fully recovered by 24 h and exceeded control values by 36–48 h. A sustained, twofold elevation of plasma ammonia concentration may have facilitated the recovery of Jamm by increasing the blood-to-water ammonia partial pressure diffusion gradient (deltaPNH3) and NH4+ electrochemical gradient. Urea excretion (Jurea) almost doubled at 24–48 h of pH 10 exposure....
page 35 General background 36 Molecular processes related to HSP expression 37 Heat shock protein... more page 35 General background 36 Molecular processes related to HSP expression 37 Heat shock protein studies in ®sh 40 Cell line studies Primary cell culture Whole animal studies Molecular characteristics of ®sh heat shock proteins The generalized stress response and HSP expression Methods of analysis 48 Applications 49 Acknowledgements 51 References 51
Earlier studies have reported that acute exposure to alkaline pH strongly inhibits ammonia excret... more Earlier studies have reported that acute exposure to alkaline pH strongly inhibits ammonia excretion in freshwater rainbow trout, but the Lahontan cutthroat trout thrives in Pyramid Lake, Nevada, at pH 9.4. We investigated the rates and mechanisms of ammonia and urea excretion in this species in Pyramid Lake water to determine whether special strategies are employed to excrete nitrogenous wastes in an environment unfavourable for ammonia excretion. The majority of nitrogen wastes (N-wastes) were excreted as ammonia (56 % through the gills, 10 % through the kidney), while urea excretion accounted for 34 % (32 % gills, 2 % kidney). Ammonia excretion was dependent on the NH3 partial pressure gradient (deltaPNH3) across the gills and independent of Na+ influx and acidification of the gill water boundary layer. Acute exposure to more alkaline water (pH 10) decreased ammonia excretion by 52 %, while exposure to neutral water (pH 7.6) increased ammonia excretion by 200 %. When fish were he...
The contribution of the secondary circulatory system to acid-base regulation and epithelial ion t... more The contribution of the secondary circulatory system to acid-base regulation and epithelial ion transport was evaluated qualitatively in freshwater-acclimated rainbow trout. The dorsal aorta (DA) and the lateral cutaneous vessel (LCV) (which is considered to be the venous drainage of the secondary system) were chronically cannulated and the fish were exposed to environmental hypercapnia (2 % CO2) after establishment of normocapnic control values. Fluid sampled from the LCV contained much less haemoglobin (0.14 g 100 ml−1) and fewer blood cells (packed cell volume, PCV, 1.2-1.7%) than DA blood ([Hb] 8.2-8.9 g 100 ml−1, PCV 27.2-32.5%) regardless of ambient CO2 levels, indicating highly limited access of red blood cells to the secondary circulatory system through anastomoses connecting it to the primary system. There was no significant difference between the two sampling sites for any of the acid-base variables (pH, PCO2 [HCO3−]) and most plasma ion concentrations ([Na+], [Ca2+], [Mg2...
Channel catfish (Ictalurus punctatus Rafinesque) were progressively acclimated to CO2 partial pre... more Channel catfish (Ictalurus punctatus Rafinesque) were progressively acclimated to CO2 partial pressures of 7.5, 15, 30, 45 and 58 mmHg (1, 2, 4, 6 and 8% CO2 in air) and blue crabs (Callinectes sapidus Rathbun) to 15, 30 and 45 mmHg, with 24 h at each partial pressure. Measurements of both conventional acid-base parameters (pH, PCO2. total CO2) and ‘strong’ ion concentrations (Na+, K+, Mg2+, Ca2+ and Cl−) were made at various times during each treatment. Intracellular [Na+], [K+] and [Cl−] were determined for red and white muscle in control and hypercapnic (8%) catfish. Extracellular [HCO3−] and strong ion difference (SID) both rose during hypercapnic compensation, with correlation coefficients (r) of 0.97 (P<0.01) for catfish and 0.41 (NS) for blue crabs. Since [HCO3−] is calculated from two rapid measurements, and SID from four separate procedures, the former appears to be the measurement of choice. The results also dispel the notion of a 30 mequiv1−1 upper limit to bicarbonate...
Acid-base regulation in rainbow trout acclimated to about 3, 100 and 500 mmol l−1 Na+ and Cl−, at... more Acid-base regulation in rainbow trout acclimated to about 3, 100 and 500 mmol l−1 Na+ and Cl−, at constant water [HCO3−], was assessed during 24h of exposure to 1% CO2 and during recovery. The respiratory acidosis induced by a rise in plasma PCOCO2 to about 1.15kPa (8.5mmHg, 3mmol l−1), 1.33kPa (10mmHg, 100 mmol l−1) or 1.5 kPa (11.2 mmHg, 500 mmol l−1) was partially compensated for by accumulation of plasma HCO3−. The degree of pH compensation depended on the salinity of the environmental water, being about 61, 82 and 88% at 3, 100 and 300 mmol l−1 Na+ and Cl−, respectively. [HCO3−] in animals acclimated to 100 and 500 mmol l−1 rose to higher values than that in fish at 3 mmol l−1. Plasma [Cl−] decreased during hypercapnia as compared to control concentrations in all groups of fish. Plasma [Na+] rose during the first 8 h of hypercapnia in fish acclimated to all three salinities, but recovered towards control values during the remainder of hypercapnia. The rise in plasma [HCO3−] was...
Http Dx Doi Org 10 1080 10643389109388413, Jan 9, 2009
Interactions between Aquaculture and the Environment. GK Iwama ... Both direct and indirect envir... more Interactions between Aquaculture and the Environment. GK Iwama ... Both direct and indirect environmental effects are considered in a review of the current literature on aquaculture of finfish, shellfish and plants. The principal ...
... Vol. 14 edited by Chris M. Wood, Trevor J. Shuttleworth. ... and Marine Biomedical and Enviro... more ... Vol. 14 edited by Chris M. Wood, Trevor J. Shuttleworth. ... and Marine Biomedical and Environmental Sciences Program, Medical University of South Carolina, Charleston, South Carolina 29425, and Mount Desert Island Biological Laboratory, Salsbury Cove, Maine 04672 Eric R ...
Comparative Biochemistry and Physiology Part a Molecular Integrative Physiology, Mar 31, 2007
Glutathione (GSH) is an important antioxidant that is involved in a multitude of cellular process... more Glutathione (GSH) is an important antioxidant that is involved in a multitude of cellular processes. However, in fish, GSH levels, turnover, and activity of associated enzymes are low when compared to those of mammals. To determine whether temperature influences the GSH antioxidant system in fish, and can explain the differences in GSH between fish and mammals, we examined the effects of acclimation temperature on total GSH (tGSH) levels and apparent half-life (as an estimate of turnover) in a rainbow trout hepatoma cell line (RTH-149), and GSH levels, and glutathione peroxidase (GPx) and reductase (GR) activity in the eurythermal killifish. Increasing incubation temperature decreased half-life and transiently increased levels of tGSH in RTH-149 cells. In killifish, increased acclimation temperature increased tGSH levels in the liver, brain and muscle, and increased hepatic GPx and GR activities. When the relationships between temperature and GSH half-life, levels and enzyme activity were extrapolated to 37 degrees C, temperature could only partially accounted for differences in the GSH antioxidant system in fish compared to mammals. The differences in the GSH antioxidant system between fish and mammals may not be solely due to temperature effects, but also to the increased metabolic cost of endothermy in mammals.
Exposure of fish to stressors can elicit biochemical and organismal changes at multiple levels of... more Exposure of fish to stressors can elicit biochemical and organismal changes at multiple levels of biological organization collectively known as stress responses. The organismal (plasma glucose and cortisol levels) and cellular (hepatic hsp70) stress responses in fish have been studied in several species, but little is known about sex-related differences in these responses. In this study, we exposed sexually immature juvenile chinook salmon (Oncorhynchus tshawytscha) to bleached kraft mill effluent (BKME: 0%, 1%, and 10% v/v) for 30 days and then measured components of their organismal and cellular stress responses. Males exposed to 1% BKME had higher levels of plasma glucose than females. Plasma cortisol levels were unaffected in females exposed to BKME, but males exposed to 10% BKME had significantly higher levels of plasma cortisol relative to non-exposed males. While exposure to BKME did not affect hsp70 levels in males, females exposed to 1% BKME had higher levels of hsp70 relative to non-exposed and 10% BKME groups. Within any given treatment, females had higher levels of hsp70 relative to males. This study demonstrates that sex-related differences exist in commonly used indicators of stress in fish, and points out the importance of considering the sex of the fish in stress research.
Proton-ATPase was localized to mitochondria-rich cells in the interlamellar region of the gills o... more Proton-ATPase was localized to mitochondria-rich cells in the interlamellar region of the gills of the elasmobranch, Squalus acanthias. Localization was accomplished using a polyclonal antibody specific for the 70 kDa subunit of the (V-type) proton-ATPase as confirmed by Western blot analysis. In addition, significant levels of N-ethymaleimide sensitive ATPase activity (0.116 +/- 0.026 mumol Pi.mg-1 protein.h-1) were also measured in crude gill membrane preparations. These data provide, for the first time, direct evidence of the localization of elements possibly involved in branchial acid-base (or ionic) regulation in elasmobranchs.
Transactions of the American Fisheries Society, 1994
Abstract In this study, we examined the ammonia and urea excretion rates in four species of fish ... more Abstract In this study, we examined the ammonia and urea excretion rates in four species of fish native to Pyramid Lake, Nevada (pH 9.4): tui chub Gila bicolor, Tahoe sucker Catostomus tahoensis, Lahontan cutthroat trout Oncorhynchus clarki henshawi, and cui-ui ...
Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology, 1998
ABSTRACT Exposure of fish to alkaline conditions clearly inhibits the rate of ammonia excretion (... more ABSTRACT Exposure of fish to alkaline conditions clearly inhibits the rate of ammonia excretion (JAMM) leading to problems of ammonia accumulation and toxicity. There is some evidence that higher environmental calcium levels may ameliorate the negative effects of alkaline exposure. In the present study, we investigated the effects of elevated environmental calcium on the recovery of ammonia excretion during acute (6 h) and chronic (15 day) exposures to high pH (pH 10), and the levels of nitrogenous products (ammonia, urea, and glutamine) in tissues and plasma (1–15 days). Acclimation to alkaline conditions results in a chronically depressed ammonia excretion rate. Glutamine as well as urea do not appear to be important in ammonia detoxification and storage. Calculations of the production rates from storage and excretion data indicate a reduction in the rate of ammonia production. Elevating environmental calcium during acute exposure to alkaline conditions does not affect the recovery of JAMM but may reduce stress. We conclude that rainbow trout survive alkaline exposure by reducing ammonia production and that the role of calcium may be in the amelioration of the stress of alkaline exposure.
Precocious sexual maturation in salmonid parr occurs under both wild and culture conditions. We i... more Precocious sexual maturation in salmonid parr occurs under both wild and culture conditions. We investigated the possibility of repeat maturation in precocious chinook salmon parr from the Nicola River, British Columbia. Precocious and immature (control) yearling parr were reared in fresh water from March 1990 to mid-June, and then transferred to salt water (29–30 ppt) until September 1990. The precocious parr were significantly larger than the controls from March to July and there were no differences in relative growth rate between the groups throughout the study. Total mortalities were 45.7 and 5.9% for precocious and control fish, respectively. All of the precocious, but none of the control fish, produced milt in March in fresh water. None of the fish produced milt soon after the transfer to salt water in June, but all precocious fish and 18.8% of the controls produced milt in September. There were no significant differences in the average plasma concentrations of Na+, Cl−, and c...
The distribution of branchial carbonic anhydrase (CA) in the shark, Squalus acanthias, was studie... more The distribution of branchial carbonic anhydrase (CA) in the shark, Squalus acanthias, was studied using in situ measurements of pH disequilibrium states in post-branchial saline, and immunological techniques, immunofluorescence microscopy and Western analysis, employing rabbit polyclonal antibodies against rat pulmonary membrane associated CA IV and chick retinal cytosolic CA II. In the in situ saline perfused gill preparation, the CA inhibitor acetazolamide produced a pH disequilibium (0.063 ± 0.022 pH units) while control and bovine carbonic anhydrase perfusions did not (0.012 ± 0.017 and 0.023 ± 0.018 pH units, respectively). These results indicate that the HCO − 3 dehydration reaction is accelerate by endogenous extracellular CA. Western analysis of saline perfused gill membrane preparations revealed an immunoreactive 48 kDa band with the CA IV probe. In crude gill homogenates, a 33 kDa and 31 kDa pair of bands is identified by the CA II probe. The pattern of immunolabeling for CA II in the gill epithelium was either diffuse or punctate within both lamellar and filament epithelial cells while eyrthrocytes and pillar cells displayed a diffuse staining pattern.
RAPID COMMUNICATION / COMMUNICATION RAPIDE Graham D. Sherwood, Jennifer Kovecses, Alice Hontela, ... more RAPID COMMUNICATION / COMMUNICATION RAPIDE Graham D. Sherwood, Jennifer Kovecses, Alice Hontela, and Joseph B. Rasmussen Simplified food webs lead to energetic bottlenecks in polluted lakes ... ARTICLES / ARTICLES Peder A. Jansen, Henning Slettvold, Anders G. Finstad, and Arnfinn Langeland Niche segregation between Arctic char (Salvelinus alpinus) and brown trout (Salmo trutta): an experimental study of mechanisms ... Franck Cattanéo, Nicolas Lamouroux, Pascal Breil, and Hervé Capra The influence of hydrological and biotic ...
The present work evaluated several aspects of the generalized stress response [endocrine (cortiso... more The present work evaluated several aspects of the generalized stress response [endocrine (cortisol), metabolic (glucose), hematologic (hematocrit and hemoglobin) and cellular (HSP70)] in the Amazonian warm-water fish matrinxã (Brycon amazonicus ) subjected to an acute cold shock. This species farming has been done in South America, and growth and feed conversion rates have been interesting. However, in subtropical areas of Brazil, where the water temperature can rapidly change, high rates of matrinxã mortality have been associated with abrupt decrease in the water temperature. Thus, we subjected matrinxã to a sudden cold shock by transferring the fish directly to tanks in which the water temperature was 10ºC below the initial conditions (cold shock from 28ºC to 18ºC). After 1h the fish were returned to the original tanks (28ºC). The handling associated with tank transfer was also imposed on control groups (not exposed to cold shock). While exposure to cold shock did not alter the me...
The Lahontan cutthroat trout lives under highly alkaline and saline conditions in Pyramid Lake, N... more The Lahontan cutthroat trout lives under highly alkaline and saline conditions in Pyramid Lake, Nevada (pH 9•4; 0•2 mmol l 1 Ca + + ; 7•3 mmol l 1 Mg + +). These experiments were conducted to study the possible roles of water Ca + + and Mg + + concentrations on ammonia excretion in the Lahontan cutthroat trout under highly alkaline conditions. The basic protocol of the experiments was to determine ammonia excretion rates during the following three exposure periods (each of 3-h duration) in sequence: (a) in normal lake water; (b) in soft lake water with the divalent cation concentrations reduced; and (c) in the soft lake water with either Ca + + or Mg + + (or no divalent cations added) added back at the appropriate lake water concentration. The soft-water exposure caused a significant reduction in ammonia excretion to about half of the control (original lake water) levels. When either Ca + + or Mg + + was added to the soft water in the third exposure period, the ammonia excretion rates were increased more than twofold back to lake water levels.
Desiccation of Pyramid Lake, Nevada, has led to continued increases in the lake's alkalinity ... more Desiccation of Pyramid Lake, Nevada, has led to continued increases in the lake's alkalinity (currently pH 9.4) that may threaten the resident Lahontan cutthroat trout population. In this study, Lahontan cutthroat trout were challenged with more alkaline water (pH 10). The objectives were to describe physiological responses which may permit survival or lead to death in future potential environmental conditions and to cast further light on the mechanisms of nitrogenous waste excretion, acid-base regulation and ionoregulation in this unusual salmonid. Ammonia excretion (Jamm) was reduced by 50 % in the first few hours, but had fully recovered by 24 h and exceeded control values by 36–48 h. A sustained, twofold elevation of plasma ammonia concentration may have facilitated the recovery of Jamm by increasing the blood-to-water ammonia partial pressure diffusion gradient (deltaPNH3) and NH4+ electrochemical gradient. Urea excretion (Jurea) almost doubled at 24–48 h of pH 10 exposure....
page 35 General background 36 Molecular processes related to HSP expression 37 Heat shock protein... more page 35 General background 36 Molecular processes related to HSP expression 37 Heat shock protein studies in ®sh 40 Cell line studies Primary cell culture Whole animal studies Molecular characteristics of ®sh heat shock proteins The generalized stress response and HSP expression Methods of analysis 48 Applications 49 Acknowledgements 51 References 51
Earlier studies have reported that acute exposure to alkaline pH strongly inhibits ammonia excret... more Earlier studies have reported that acute exposure to alkaline pH strongly inhibits ammonia excretion in freshwater rainbow trout, but the Lahontan cutthroat trout thrives in Pyramid Lake, Nevada, at pH 9.4. We investigated the rates and mechanisms of ammonia and urea excretion in this species in Pyramid Lake water to determine whether special strategies are employed to excrete nitrogenous wastes in an environment unfavourable for ammonia excretion. The majority of nitrogen wastes (N-wastes) were excreted as ammonia (56 % through the gills, 10 % through the kidney), while urea excretion accounted for 34 % (32 % gills, 2 % kidney). Ammonia excretion was dependent on the NH3 partial pressure gradient (deltaPNH3) across the gills and independent of Na+ influx and acidification of the gill water boundary layer. Acute exposure to more alkaline water (pH 10) decreased ammonia excretion by 52 %, while exposure to neutral water (pH 7.6) increased ammonia excretion by 200 %. When fish were he...
The contribution of the secondary circulatory system to acid-base regulation and epithelial ion t... more The contribution of the secondary circulatory system to acid-base regulation and epithelial ion transport was evaluated qualitatively in freshwater-acclimated rainbow trout. The dorsal aorta (DA) and the lateral cutaneous vessel (LCV) (which is considered to be the venous drainage of the secondary system) were chronically cannulated and the fish were exposed to environmental hypercapnia (2 % CO2) after establishment of normocapnic control values. Fluid sampled from the LCV contained much less haemoglobin (0.14 g 100 ml−1) and fewer blood cells (packed cell volume, PCV, 1.2-1.7%) than DA blood ([Hb] 8.2-8.9 g 100 ml−1, PCV 27.2-32.5%) regardless of ambient CO2 levels, indicating highly limited access of red blood cells to the secondary circulatory system through anastomoses connecting it to the primary system. There was no significant difference between the two sampling sites for any of the acid-base variables (pH, PCO2 [HCO3−]) and most plasma ion concentrations ([Na+], [Ca2+], [Mg2...
Channel catfish (Ictalurus punctatus Rafinesque) were progressively acclimated to CO2 partial pre... more Channel catfish (Ictalurus punctatus Rafinesque) were progressively acclimated to CO2 partial pressures of 7.5, 15, 30, 45 and 58 mmHg (1, 2, 4, 6 and 8% CO2 in air) and blue crabs (Callinectes sapidus Rathbun) to 15, 30 and 45 mmHg, with 24 h at each partial pressure. Measurements of both conventional acid-base parameters (pH, PCO2. total CO2) and ‘strong’ ion concentrations (Na+, K+, Mg2+, Ca2+ and Cl−) were made at various times during each treatment. Intracellular [Na+], [K+] and [Cl−] were determined for red and white muscle in control and hypercapnic (8%) catfish. Extracellular [HCO3−] and strong ion difference (SID) both rose during hypercapnic compensation, with correlation coefficients (r) of 0.97 (P<0.01) for catfish and 0.41 (NS) for blue crabs. Since [HCO3−] is calculated from two rapid measurements, and SID from four separate procedures, the former appears to be the measurement of choice. The results also dispel the notion of a 30 mequiv1−1 upper limit to bicarbonate...
Acid-base regulation in rainbow trout acclimated to about 3, 100 and 500 mmol l−1 Na+ and Cl−, at... more Acid-base regulation in rainbow trout acclimated to about 3, 100 and 500 mmol l−1 Na+ and Cl−, at constant water [HCO3−], was assessed during 24h of exposure to 1% CO2 and during recovery. The respiratory acidosis induced by a rise in plasma PCOCO2 to about 1.15kPa (8.5mmHg, 3mmol l−1), 1.33kPa (10mmHg, 100 mmol l−1) or 1.5 kPa (11.2 mmHg, 500 mmol l−1) was partially compensated for by accumulation of plasma HCO3−. The degree of pH compensation depended on the salinity of the environmental water, being about 61, 82 and 88% at 3, 100 and 300 mmol l−1 Na+ and Cl−, respectively. [HCO3−] in animals acclimated to 100 and 500 mmol l−1 rose to higher values than that in fish at 3 mmol l−1. Plasma [Cl−] decreased during hypercapnia as compared to control concentrations in all groups of fish. Plasma [Na+] rose during the first 8 h of hypercapnia in fish acclimated to all three salinities, but recovered towards control values during the remainder of hypercapnia. The rise in plasma [HCO3−] was...
Http Dx Doi Org 10 1080 10643389109388413, Jan 9, 2009
Interactions between Aquaculture and the Environment. GK Iwama ... Both direct and indirect envir... more Interactions between Aquaculture and the Environment. GK Iwama ... Both direct and indirect environmental effects are considered in a review of the current literature on aquaculture of finfish, shellfish and plants. The principal ...
... Vol. 14 edited by Chris M. Wood, Trevor J. Shuttleworth. ... and Marine Biomedical and Enviro... more ... Vol. 14 edited by Chris M. Wood, Trevor J. Shuttleworth. ... and Marine Biomedical and Environmental Sciences Program, Medical University of South Carolina, Charleston, South Carolina 29425, and Mount Desert Island Biological Laboratory, Salsbury Cove, Maine 04672 Eric R ...
Comparative Biochemistry and Physiology Part a Molecular Integrative Physiology, Mar 31, 2007
Glutathione (GSH) is an important antioxidant that is involved in a multitude of cellular process... more Glutathione (GSH) is an important antioxidant that is involved in a multitude of cellular processes. However, in fish, GSH levels, turnover, and activity of associated enzymes are low when compared to those of mammals. To determine whether temperature influences the GSH antioxidant system in fish, and can explain the differences in GSH between fish and mammals, we examined the effects of acclimation temperature on total GSH (tGSH) levels and apparent half-life (as an estimate of turnover) in a rainbow trout hepatoma cell line (RTH-149), and GSH levels, and glutathione peroxidase (GPx) and reductase (GR) activity in the eurythermal killifish. Increasing incubation temperature decreased half-life and transiently increased levels of tGSH in RTH-149 cells. In killifish, increased acclimation temperature increased tGSH levels in the liver, brain and muscle, and increased hepatic GPx and GR activities. When the relationships between temperature and GSH half-life, levels and enzyme activity were extrapolated to 37 degrees C, temperature could only partially accounted for differences in the GSH antioxidant system in fish compared to mammals. The differences in the GSH antioxidant system between fish and mammals may not be solely due to temperature effects, but also to the increased metabolic cost of endothermy in mammals.
Exposure of fish to stressors can elicit biochemical and organismal changes at multiple levels of... more Exposure of fish to stressors can elicit biochemical and organismal changes at multiple levels of biological organization collectively known as stress responses. The organismal (plasma glucose and cortisol levels) and cellular (hepatic hsp70) stress responses in fish have been studied in several species, but little is known about sex-related differences in these responses. In this study, we exposed sexually immature juvenile chinook salmon (Oncorhynchus tshawytscha) to bleached kraft mill effluent (BKME: 0%, 1%, and 10% v/v) for 30 days and then measured components of their organismal and cellular stress responses. Males exposed to 1% BKME had higher levels of plasma glucose than females. Plasma cortisol levels were unaffected in females exposed to BKME, but males exposed to 10% BKME had significantly higher levels of plasma cortisol relative to non-exposed males. While exposure to BKME did not affect hsp70 levels in males, females exposed to 1% BKME had higher levels of hsp70 relative to non-exposed and 10% BKME groups. Within any given treatment, females had higher levels of hsp70 relative to males. This study demonstrates that sex-related differences exist in commonly used indicators of stress in fish, and points out the importance of considering the sex of the fish in stress research.
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