Relationship Between Ammonia Excretion Rates and Hemolymph Nitrogenous Compounds of a Euryhaline Bivalve During Low Salinity Acclimation ,

Bartberger, Carol A.; Pierce, Sidney K.

doi:10.2307/1540585

Cited by 65 publications

(13 citation statements)

References 26 publications

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“…The mean blood ammonla concentration found (Table 3) was 482.53 pm01 NH4-N I-', which accords with the seasonal range of 171.93 to 992.00 pm01 NH4-N 1-' given for Mytilus edulis (Bayne 1973a) and is similar to the haemolymph ammonia level of 2 mM NH4-N for Rangia cuneata (Mangum et al 1978) and the 500 to 600 pm01 NH,-N I-' for Modiolus demissus (Bartberger & Pierce 1976). M. edulis exposed to supranormal concentrations of ambient ammonia had blood ammonia levels significantly higher than normal (p < 0.05).…”

Section: Discussionsupporting

confidence: 83%

Fluxes of haemolymph ammonia and free amino acids in Mytilus edulis exposed to ammonia

Sadok¹,

Uglow²,

Haswell³

1995

Mar. Ecol. Prog. Ser.

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Survival, weight-specific ammonia fluxes, blood ammonia levels and pH values were measured in individual mussels Mytilus edulls (L.) (n = 6 in each group) sampled after various acute exposures (max. 2 h) in normal or ammonia-enriched seawater Ammonia influxes occurred when external ammonia was 2100 pm01 I-' when, within 5 min, mean blood ammonia levels increased significantly by an amount directly proportional to the medium ammonia concentration. Blood pH showed an initial alkalosls followed by a slow acidosis. Blood ninhydnn-positive substance (NPS) levels showed a less rapid medium-NH4 concentration-dependent elevation and only the 100 inmol l-'-treated mussels showed a signlf~cant increase in blood NPS after 5 min exposure. Wlth~n the 2 h test period, no mortalities occurred in any group, though 50% of the 100 mm01 l-'-treated group subsequently died after 6 h exposure. Apart from those in the most concentrated test medium, all mussels were seen to use apparently normal pumping behaviour, and it was concluded that M. edulis is an ammonia-tolerant species, capable of tolerating very high blood ammonia levels for extended periods of time. The toxic effect may be related more to the rate at which ammonia influx occurs, with the attendant level of disruption to the regulation of blood NPS levels, rather than to the actual blood ammonia concentration attained.

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Section: Discussionsupporting

confidence: 83%

Fluxes of haemolymph ammonia and free amino acids in Mytilus edulis exposed to ammonia

Sadok¹,

Uglow²,

Haswell³

1995

Mar. Ecol. Prog. Ser.

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“…Greater GDH function in this tissue in low-salinity animals identifies this tissue as the major site of deamination in low salinity. Higher rates of ammonia/ammonium excretion are correlated with losses of amino acids from tissues of bivalves in low salinity (Bartenberger and Pierce 1976). GDH is known to be activated by increasing ionic strength in crustaceans (Gilles 1974; Schoffeniels 19'76), but we have found oyster GDH to be inhibited by increasing ionic strength (Ballantyne and Moyes 198'7~).…”

Section: Effects Of Salinity Exposurementioning

confidence: 63%

Enzyme Activities of Gill, Hepatopancreas, Mantle, and Adductor Muscle of the Oyster (Crassostrea virginica) after Changes in Diet and Salinity

Ballantyne¹,

Berges²

1991

Can. J. Fish. Aquat. Sci.

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Ballantyne, I. S., and 8 . A. Berges. 1991. Enzyme activities of gill, hepatopancreas, mantle, and adductor muscle of the oyster (Crassostrea virginica) after changes in diet and salinity. Can. 1. Fish. Aquat. Sci. 48: 1 1 1 7- 1123.We examined the effects of exposure to low salinity (113 seawater) on the maximal activities of enzymes of lipid oxidation, amino acid and ketone body metabolism, gluconeogenesis, and glycolysis in gill, mantle, hepatopancreas, and adductor muscle of the oyster (Crassostsea virginica). No significant metabolic reorganization occurred after 4-6 wk in low salinity. The few significant differences which were found between enzyme activities of high-and low-salinity treatment groups were always due to lower activities in the low-salinity group. In particular, hexokinase, fructose bisphosphatase, and 3-hydroxyacyl CoA dehydrogenase declined in gill, hepatopancreas, and adductor muscle. Since high ionic strength depresses the activity of many enzymes, the reduced ionic strength in the cells of the low-salinity group may perturb metabolism by elevating rates of enzyme activity. As indicated by the present study, part of the response to low salinity by euryhaline molluscs may involve reducing the activity of certain enzymes to achieve a homeostasis of metabolic function.On a 6tudi6 les effets de la salinit6 reduite 6113 dfeau sake) sur 11activit6 maximale des enzymes de I'oxydation tipidique, du m6tabolisme des acides amines et des corps cetoniques, de la glucon6ogen2se et de la glycolyse dans les branchies, te manteau, I1h6pato-pancreas et le muscle adducteur de l'huitre (Csasssstrea virginica).Aucune reorganisation m6tabolique n16tait notable au bout de 4 a 6 sem en salinit6 r6duite. hes quelques differences significatives obsewees entre les groupes gard6s 2 salinit6 6lev6e et r6duite 6taient toujours dues a des activites enzymatiques moindres chez le groupe garde 3 satinit6 r6duite. Plus particuli&rement, on a not6 la baisse de 11activit6 de I'hexokinase, de la.fructose-biphosph9tase et de la 3-hydroxyacyl-CoA-d6shydrog6nase dans les branchies, 11h6patopancr6as et le muscle adducteur. Etant donn6 qu'h concentration ionique 6levke 11activit6 de nombreuses enzymes diminue, le fait que la concentration ionique soit rkduite dans les cellules des hui'tres gard6es salinitk r6duite peut perturber le m6tabolisme en stimulant 11activit6 enzyrnatique. Comme on I'a constat6 dans 116tude present& ici, en partie, la reaction des mollusques euryhalins 3 une baisse de salinit6 peut gtre une diminution de l"ctivit6 de certaines enzymes pour le rnaintien de I'hom6sstase de la fonction m6tabsl ique.

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“…In mammals, deamination of amino acids occurs primarily in the liver, with ammonia released in the GDH reaction. Gill (Zurburg and de Zwaan 198 1) and mantle (Bartberger and Pierce 1976) may be centralized tissues for deamination of amino acid osmolytes in hypoosmotically stressed bivalve molluscs. Mitochondria from these tissues oxidize many of the important amino acid osmolytes at high rates.…”

Section: Amino Acid Metabolism In Osmoconformersmentioning

confidence: 99%

A comparison of fuel preferences of mitochondria from vertebrates and invertebrates

Moyes¹,

Suarez²,

Hochachka³

et al. 1990

Can. J. Zool.

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1990. A comparison of fuel preferences of mitochondria from vertebrates and invertebrates. Can. J. Zool. 68: 1337-1349.Knowledge of tissue-specific mitochondrial properties is important in understanding cellular aerobic energy metabolism. Studies employing isolated mitochondria offer the advantage of direct and controlled manipulation of extramitochondrial conditions, while minimizing disruption of interactions between mitochondrial enzymes, transporters, and membranes. In this review, we compare the oxidative properties of mitochondria isolated from liver, heart, and skeletal muscle of vertebrates and invertebrates. The observed differences between tissues and species in the capacities for mitochondrial oxidation of fatty acids, ketone bodies, pyruvate, and amino acids reflect fundamentally different adaptations for the assimilation, storage, and utilization of metabolic fuels. MOYES, C. D., SUAREZ, R. K., HOCHACHKA, P. W., et BALLANTYNE, J. S. 1990. A comparison of fuel preferences of mitochondria from vertebrates and invertebrates. Can. J. Zool. 68 : 1337-1349. La connaissance des propriCtCs mitochondriales spCcifiques A certains tissus est essentielle A la comprChension du mCtabolisme CnergCtique aCrobie des cellules. Les travaux sur des mitochondries isolCes offrent l'avantage d'une manipulation directe et contr61Ce des conditions extramitochondriales tout en affectant le moins possible les interactions entre les enzymes, les ClCments de transport et les membranes des mitochondries. Dans cette synthkse, nous comparons les propriCtCs oxydatives de mitochondries isolCes du foie, du coeur et du muscle squelettjque de vertCbrCs et d'invertCbrCs. Les diffkrences observCes entre divers tissus et entre diffkrentes especes quant A la capacitC mitochondriale d'oxydation des acides gras, des corps cktoniques, des pyruvates et des acides aminCs sont le reflet des adaptations fondamentalement diffkrentes qui rCgissent l'assimilation, le stockage et l'utilisation des comburants mCtaboliques. [Traduit par la revue]Introduction may provide models that are better suited for the study of Cellular energy production via the oxidation of glucose, fatty acids, ketone bodies, and amino acids requires participation of rnitachondrial transporters, rnitochondrial matrix and membranebound enzymes, and oxidative phosphorylation. Consequently, studies of metabolite oxidation by isolated mitochondria provide insights into the fuel preferences of various tissues. Because studies that make use of isolated mitochondria minimize disruption of enzyme-enzyme, enzyme-membrane, and enzyme-transporter interactions, they are useful in assessing transport capacities, metabolic flux rates, enzyme activities in situ, and regulation of mitochondrial pathways. Such studies may also yield important information about anabolic capacities,

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Relationship Between Ammonia Excretion Rates and Hemolymph Nitrogenous Compounds of a Euryhaline Bivalve During Low Salinity Acclimation ,

Abstract: Marine invertebrates utilize intracellular free amino acids as the solute for cell volume regulation during environmental salinity stress (marine ciliates, Kaneshiro,

Cited by 65 publications

References 26 publications

Fluxes of haemolymph ammonia and free amino acids in Mytilus edulis exposed to ammonia

Fluxes of haemolymph ammonia and free amino acids in Mytilus edulis exposed to ammonia

Enzyme Activities of Gill, Hepatopancreas, Mantle, and Adductor Muscle of the Oyster (Crassostrea virginica) after Changes in Diet and Salinity

A comparison of fuel preferences of mitochondria from vertebrates and invertebrates

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