Energetics of osmoregulation in fresh water vertebrates

Kirschner, Leonard B.

doi:10.1002/jez.1402710402

Cited by 64 publications

(35 citation statements)

References 30 publications

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“…A similar mechanism also seems to be exhibited by fish gills upon environmental salinity challenge. It has been well documented in fish that more energy is required to support the activation of gill Na ϩ -K ϩ -ATPase expression and activity during acclimation to different salinities (20,23,27,29). The present study examines for the first time the cellular and molecular mechanisms of emergent energy metabolism for the ionoregulation and osmoregulation processes in fish gills.…”

Section: Discussionmentioning

confidence: 94%

Glycogen phosphorylase in glycogen-rich cells is involved in the energy supply for ion regulation in fish gill epithelia

Tseng¹,

Huang²,

Chang³

et al. 2007

American Journal of Physiology-Regulatory, Integrative and Comp

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The molecular and cellular mechanisms behind glycogen metabolism and the energy metabolite translocation between mammal neurons and astrocytes have been well studied. A similar mechanism is proposed for rapid mobilization of local energy stores to support energy-dependent transepithelial ion transport in gills of the Mozambique tilapia (Oreochromis mossambicus). A novel gill glycogen phosphorylase isoform (tGPGG), which catalyzes the initial degradation of glycogen, was identified in branchial epithelial cells of O. mossambicus. Double in situ hybridization and immunocytochemistry demonstrated that tGPGG mRNA and glycogen were colocalized in glycogen-rich cells (GRCs), which surround ionocytes (labeled with a Na(+)-K(+)-ATPase antiserum) in gill epithelia. Concanavalin-A (a marker for the apical membrane) labeling indicated that GRCs and mitochondria-rich cells share the same apical opening. Quantitative real-time PCR analyses showed that tGPGG mRNA expression levels specifically responded to environmental salinity changes. Indeed, the glycogen content, glycogen phosphorylase (GP) protein level and total activity, and the density of tGPGG-expressing cells (i.e., GRCs) in fish acclimated to seawater (SW) were significantly higher than those in freshwater controls. Short-term acclimation to SW caused an evident depletion in the glycogen content of GRCs. Taken altogether, tGPGG expression in GRCs is stimulated by hyperosmotic challenge, and this may catalyze initial glycogen degradation to provide the adjacent ionocytes with energy to carry out iono- and osmoregulatory functions.

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Section: Discussionmentioning

confidence: 94%

Glycogen phosphorylase in glycogen-rich cells is involved in the energy supply for ion regulation in fish gill epithelia

Tseng¹,

Huang²,

Chang³

et al. 2007

American Journal of Physiology-Regulatory, Integrative and Comp

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“…These results concur with the notion that, theoretically, energy expenditure for osmoregulation, which may represent from as much as 20% to slightly above 50% of the metabolic energy, is at its minimum in an isosmotic environment, as shown in classical studies (Rao, ; Otto, ; Nordlie & Lefler, ; Nordlie, ; Furspan et al ., ), allowing more energy from ingested food to be allocated to growth. Subsequent studies have shown that the cost of osmoregulation appears not to be, after all, very high, with 10% or less of the total metabolic demands (Kirschner, , ; Morgan & Iwama, ). Bearing this in mind, studies have attempted to explain the superior growth observed for some species, at or near isosmotic salinity, in terms of endocrinally‐triggered higher food‐ingestion rates (Bœuf & Payan, ).…”

Section: Discussionmentioning

confidence: 99%

The effects of environmental salinity on the growth and physiology of totoaba Totoaba macdonaldi and shortfin corvina Cynoscion parvipinnis

González-Félix

Pérez-Velázquez

Cañedo-Orihuela

2017

Journal of Fish Biology

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Totoaba Totoaba macdonaldi and shortfin corvina Cynoscion parvipinnis, were acclimated and reared together at salinities of 0, 2, 5, 10, 20 and 35 for 56 days. Initial overall mean ± s.d. body masses of 67·6 ± 7·1 g T. macdonaldi and 37·3 ± 3·1 g C. parvipinnis increased to final overall masses of 217·4 ± 30·3 and 96·5 ± 16·5 g, respectively, at the end of the study. Totoaba macdonaldi was not able to tolerate salinities of 0 and 2 and C. parvipinnis of 0. In contrast, both species had 100% survival at salinities ≥ 10. Somatic growth was highest not at natural seawater salinity of 35, but at 10. Plasma osmolality ranged from 172·5 to 417·0 mOsmol kg for T. macdonaldi and from 207·0 to 439·5 mOsmol kg for C. parvipinnis and varied in direct proportion to salinity. The estimated isosmotic salinities of T. macdonaldi and C. parvipinnis were 12·3 and 13·4, respectively. Cynoscion parvipinnis reared at two had significantly lower plasma lysozyme activity (95·0 Units ml ) than fish held at salinities from 5 to 35 (ranging from 215·0 to 355·0 Units ml ), but without clear trends over this range. Blood neutrophil oxidative radical production (NBT) (ranging from 3·9 to 6·7 mg ml ) had some significant differences among salinities, but these did not follow a clear pattern. For T. macdonaldi, neither lysozyme activity nor NBT was affected by salinity. Ash content of whole fishes varied directly and moisture content inversely, with salinity for both species.

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“…Metabolic influences of salinity on fish are attributable to the cost of osmoregulation, changes in ion transport, and the impact of salinity stress (Morgan and Iwama 1991;Kirschner 1995). A commonly observed phenomenon is that of higher growth rates in mesohaline salinities (salinities of 5-18), which are often attributed to decreased osmoregulatory costs associated with isotonic (salinities of 9-12) environments (Morgan and Iwama 1991;Boeuf and Payan 2001).…”

Section: Introductionmentioning

confidence: 99%

Bioenergetic trajectories underlying partial migration in Patuxent River (Chesapeake Bay) white perch (Morone americana)

Kerr

Secor

2009

Can. J. Fish. Aquat. Sci.

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Partial migration, the coexistence of resident and migratory individuals within the same population, may be common in fish populations. A proposed mechanism underlying partial migration is differing dispersive responses to early growth conditions, but few studies have explicitly tested this. During their first year of life, white perch (Morone americana) in the Patuxent River (Maryland, USA) exhibit either residency in freshwater natal habitats (resident contingent) or disperse down-estuary into brackish habitats (dispersive contingent). We tested whether white perch juveniles exhibited differing growth and metabolic trajectories based on contingent membership or in response to salinity. A randomized factorial experiment with two contingent types and two salinity treatments (1 and 8) was conducted over a 30-day period. The experiments supported a contingent effect, with the dispersive contingent exhibiting higher consumption rates and a higher scope for growth. In addition, we identified a weak salinity effect with evidence of increased consumption and routine metabolism in mesohaline conditions. Juvenile growth rates calculated from individuals in the field supported laboratory results, with dispersive contingent members exhibiting higher growth rates. We conclude that contingent membership and the related phenomenon of partial migration in this population is associated with varying energetic tactics that significantly influence the scope for growth.Résumé : La migration partielle, la coexistence d'individus résidants et migrateurs au sein d'une même population, peut être répandue chez les populations de poissons. Un mécanisme sous-jacent proposé pour expliquer la migration partielle est la présence de réactions différentes de dispersion aux conditions du début de la croissance; peu d'études l'ont cependant testé de façon explicite. Durant leur première année d'existence, les jeunes barets (Morone americana) de la rivière Patuxent (Maryland, É .-U.) ou bien demeurent dans leurs habitats natals d'eau douce (contingent résidant) ou se dispersent en aval dans l'estuaire dans des habitats saumâtres (contingent dispersé). Nous testons si les jeunes barets ont des trajectoires différentes de croissance et de métabolisme selon leur appartenance à l'un ou l'autre contingent et d'après leur réac-tion à la salinité. Une expérience factorielle aléatoire présentant deux types de contingent et deux conditions de salinité (1 et 8) a été menée pendant 30 jours. Les résultats confirment l'existence d'un effet du contingent; le contingent dispersé possède des taux de consommation plus élevés et des perspectives de croissance plus grandes. Nous identifions, en plus, un faible effet de la salinité avec une consommation et un métabolisme de base accrus dans les conditions mésohalines. Les taux de croissance juvéniles obtenus chez des jeunes en nature confirment les résultats de laboratoire, car les membres du contingent dispersé possèdent des taux de croissance plus élevés. Nous concluons que l'appartenance à un contingent et le ph...

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Energetics of osmoregulation in fresh water vertebrates

Cited by 64 publications

References 30 publications

Glycogen phosphorylase in glycogen-rich cells is involved in the energy supply for ion regulation in fish gill epithelia

Glycogen phosphorylase in glycogen-rich cells is involved in the energy supply for ion regulation in fish gill epithelia

The effects of environmental salinity on the growth and physiology of totoaba Totoaba macdonaldi and shortfin corvina Cynoscion parvipinnis

Bioenergetic trajectories underlying partial migration in Patuxent River (Chesapeake Bay) white perch (Morone americana)

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