Ecophysiological studies on citrate-synthase: (I) enzyme regulation of selected crustaceans with regard to temperature adaptation

Vetter, R. A. H.

doi:10.1007/bf00264685

Cited by 28 publications

(16 citation statements)

References 26 publications

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“…A substantial reduction in the energy of activation may play a role (Vetter 1995a), which was partly confirmed in our laboratory but is apparently influenced by individual and (or) geographic variation (R. Müller, Alfred Wegener Institut for Polar and Marine Research, c/o Biologische Anstalt Helgoland, Marine Station, Postfach 180, D-27483 Helgoland, Germany, personal communication). Experimental acclimation showed no capacity to adjust specific activities to varied temperatures (Vetter 1995a). All of these results underline the strictly stenothermal characteristics in the Antarctic krill.…”

Section: Metabolic Enzymes: Cssupporting

confidence: 71%

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Metabolic and enzymatic adaptations in northern krill, Meganyctiphanes norvegica, and Antarctic krill, Euphausia superba

Búchholz¹,

Saborowski²

2000

Journal canadien des sciences halieutiques et aquatiques

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Abstract:The Antarctic krill, Euphausia superba, is restricted to the Antarctic Ocean. The northern krill, Meganyctiphanes norvegica, is extremely widely distributed from the arctic North Atlantic to the warm Mediterranean. Respiration measurements showed no seasonal differences in rates determined in krill from the thermally stable Clyde Sea (Scotland) and the cooler but variable Danish Kattegat. In the warm Ligurian Sea, where temperatures are stable, krill showed higher rates in April than in September, indicating reactions to the short but intensive productive season. Krill can passively benefit from enhancements of overall metabolism when ascending into upper, warmer water strata during their pronounced diel vertical migration. Michaelis-Menten constants (K m ) of citrate synthase (CS) were compared. In terms of respiration and enzyme regulation, krill from the Ligurian Sea stand apart: temperature and nutrition appear to be of different influence, relatable to genetic differentiation in the species. In contrast, K m of CS in E. superba is temperature independent, highlighting the species' stenothermal physiology. A basal level of activity of digestive enzymes ensures immediate utilization of patchy food sources. Specific induction, including that of chitinases, indicating omnivory in both species, underlines krill's exceptional capacity to adapt to highly variable trophic environments. Processes of moult, growth, and reproduction are locally and seasonally adjusted.Résumé : Le krill antarctique, Euphausia superba, n'habite que l'Océan antarctique, alors que le krill nordique, Meganyctiphanes norvegica, possède une répartition géographique très étendue qui va de la région arctique de l'Atlantique Nord aux eaux chaudes de la Méditerranée. Les taux respiratoires n'accusent pas de variation saisonnière chez le krill de la mer de Clyde en Écosse, un milieu à forte stabilité thermique, ni chez celui du Cattégat danois, une mer plus froide et plus changeante. Dans la mer Ligurienne, où les températures sont chaudes et stables, le krill a des taux respiratoires plus élevés en avril qu'en septembre, en réaction à la courte mais intense saison de production. Le krill peut bénéficier passivement d'un accroissement général de son métabolisme lorsqu'il se déplace vers les couches d'eau supérieures plus chaudes durant sa migration verticale quotidienne marquée. Nous avons comparé les constantes de Michaelis-Menten (K m ) de la citrate synthase (CS). En ce qui a trait à la respiration et la régulation enzymatique, le krill de la mer Ligurienne fait bande à part: la température et la nutrition semblent y avoir une influence particulière, à cause d'une différentiation génétique chez l'espèce. En revanche, la K m de la citrate synthase est indépendante de la température chez E. superba, une caractéristique physiologique d'une espèce sténotherme. Le maintien d'un niveau d'activité de base chez les enzymes digestives permet l'utilisation immédiate de ressources alimentaires à répartition contagieuse. L'induction spécifique, e...

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Section: Metabolic Enzymes: Cssupporting

confidence: 71%

“…Maintenance experiments showed, however, that the species adjusts specific activity of CS to different temperatures during acclimation over 11 days (Vetter 1995a).…”

Section: Metabolic Enzymesmentioning

confidence: 96%

Metabolic and enzymatic adaptations in northern krill, Meganyctiphanes norvegica, and Antarctic krill, Euphausia superba

Búchholz¹,

Saborowski²

2000

Journal canadien des sciences halieutiques et aquatiques

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“…The parameters R 0 , b , c , d and E i were estimated in a non‐linear least‐squares regression using the Gauss‐Newton algorithm. E i was estimated as it varies between species and was not known for the species studied (Vetter 1995, Gillooly et al 2001).…”

Section: Methodsmentioning

confidence: 99%

Intraspecific temperature dependence of the scaling of metabolic rate with body mass in fishes and its ecological implications

Ohlberger

Mehner

Staaks

et al. 2011

Oikos

123

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Metabolism constitutes a fundamental property of all organisms. Metabolic rate is commonly described to scale as a power function of body size and exponentially with temperature, thereby treating the effects of body size and temperature independently. Mounting evidence shows that the scaling of metabolic rate with body mass itself depends on temperature. Across‐species analyses in fishes suggest that the mass‐scaling exponent decreases with increasing temperature. However, whether this relationship holds at the within‐species level has rarely been tested. Here, we re‐analyse data on the metabolic rates of four freshwater fish species, two coregonids and two cyprinids, that cover wide ranges of body masses and their naturally experienced temperatures. We show that the standard metabolic rate of the coregonids is best fit when accounting for a linear temperature dependence of the scaling of metabolic rate with body mass, whereas a constant mass‐scaling exponent is supported in case of the cyprinids. Our study shows that phenotypic responses to temperature can result in temperature‐dependent scaling relationships at the species level and that these responses differ between taxa. Together with previous findings, these results indicate that evolutionarily adaptive and phenotypically plastic responses to temperature affect the scaling of metabolic rate with body mass in fishes.

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“…No distinct adaptive properties of Northern krill CS with respect to steno-or eurythermy were found in terms of specific activities, activation energy, pH/activity profiles or Michaelis-Menten constants (Vetter, 1995a). However, short-term acclimation experiments with krill from the Swedish Gullmarsfjord indicated reduced K M -values as well as elevated specific activities at ambient maintenance temperatures (Vetter, 1995a).…”

Section: Key Metabolic Enzymesmentioning

confidence: 96%

“…However, short-term acclimation experiments with krill from the Swedish Gullmarsfjord indicated reduced K M -values as well as elevated specific activities at ambient maintenance temperatures (Vetter, 1995a). The author suggested that M. norvegica is capable of increasing CS synthesis or producing alternative CS-isoforms with a higher specific activity to compensate enzyme activities when the animals are exposed to temperature changes.…”

Section: Key Metabolic Enzymesmentioning

confidence: 99%

Physiology and Metabolism of Northern Krill (Meganyctiphanes norvegica Sars)

Spicer

Saborowski

2010

Advances in Marine Biology

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Ecophysiological studies on citrate-synthase: (I) enzyme regulation of selected crustaceans with regard to temperature adaptation

Cited by 28 publications

References 26 publications

Metabolic and enzymatic adaptations in northern krill, <i>Meganyctiphanes norvegica</i>, and Antarctic krill, <i>Euphausia superba</i>

Metabolic and enzymatic adaptations in northern krill, <i>Meganyctiphanes norvegica</i>, and Antarctic krill, <i>Euphausia superba</i>

Intraspecific temperature dependence of the scaling of metabolic rate with body mass in fishes and its ecological implications

Physiology and Metabolism of Northern Krill (Meganyctiphanes norvegica Sars)

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