A Simple Method to Determine the O:N Ratio of Small Marine Animals

Snow, N. B.; Williams, Peter

doi:10.1017/s0025315400006494

Cited by 50 publications

(20 citation statements)

References 9 publications

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“…The low O/N ratios of 4.0-4.5 determined in normoxic, normocapnic control samples (Langenbuch and Pörtner, 2002) clearly show that energy requirements of muscle tissue are exclusively covered by protein catabolism (Cowey and Corner, 1963;Snow and Williams, 1971;Mayzaud and Conover, 1988). A further drop of O/N ratios to values around 3.0 indicated a change in the mixture of metabolized amino acids to preferred oxidative decarboxylation and catabolism of dicarboxylic, low O/N amino acids like asparagine, glutamic acid or glutamine.…”

Section: Discussionmentioning

confidence: 98%

Effects of environmental hypercapnia on animal physiology: A 13C NMR study of protein synthesis rates in the marine invertebrate Sipunculus nudus

Langenbuch

Bock

Leibfritz

et al. 2006

Comparative Biochemistry and Physiology Part A: Molecular &

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Global climate change is associated with a progressive rise in ocean CO 2 concentrations (hypercapnia) and, consequently, a drop in seawater pH. However, a comprehensive picture of the physiological mechanisms affected by chronic CO 2 stress in marine biota is still lacking. Here we present an analysis of protein biosynthesis rates in isolated muscle of the marine invertebrate Sipunculus nudus, a sediment dwelling worm living at various water depths. We followed the incorporation of 13 C-labelled phenylalanine into muscular protein via high-resolution NMR spectroscopy. Protein synthesis decreased by about 60% at a medium pH of 6.70 and a consequently lowered intracellular pH (pHi). The decrease in protein synthesis rates is much stronger than the concomitant suppression of protein degradation (60% versus 10-15%) possibly posing a threat to the cellular homeostasis of structural as well as functional proteins. Considering the progressive rise in ocean CO 2 concentrations, permanent disturbances of cellular protein turnover might seriously affect growth and reproductive performance in many marine organisms with as yet unexplored impacts on species density and composition in marine ecosystems.

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Section: Discussionmentioning

confidence: 98%

Effects of environmental hypercapnia on animal physiology: A 13C NMR study of protein synthesis rates in the marine invertebrate Sipunculus nudus

Langenbuch

Bock

Leibfritz

et al. 2006

Comparative Biochemistry and Physiology Part A: Molecular &

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“…Ammonia makes up 70 to 87% of total excreted nitrogen in marine amphipods (Dresel & Moyle 1950), 60 to 100% in the copepods Calanus helgolandicus (Corner & Newel1 1967) and Tigriopus brevicornis (Harris 1973), 72% in spiny lobster Fasus edwardsi (Binns & Peterson 1969), 86% in Carcinus maenas (Needham 1957) and 95 % in Atlantic ditch shrimp Palaemontes varians (Snow & Williams 1971) and common shrimp Crangon crangon (Regnault 1983). Regnault (1987) reported that in decapod crustaceans, ammonia and amino acid accounted for 60 to 70 and 10 % respectively of total nitrogen excreted.…”

Section: 9472c + 5421 1 3 S (R2 = 046)mentioning

confidence: 99%

Nitrogen excretion and changes of hemocyanin, protein and free amino acid levels in the hemolymph of Penaeus monodon exposed to different concentrations of ambient ammonia-N at different salinity levels

Chen¹,

Chen²,

Cheng³

1994

Mar. Ecol. Prog. Ser.

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ABSTRACT. Penaeus monodon (22.064 * 2.263 g) were exposed individually at 10, 20 and 30% salinity to 0 (control), 1, 5, 10 and 20 mg 1-' ammonia-N for 24 h. Changes in hemocyanin, protein and free amino acid levels, and whole shrimp ammonia-N excretion, urea-N excretion and dissolved organic N (DON) excretion were determined. Ammonia-N excretion decreased with increased salinity and with increased ambient ammonia-N. Ammonia-N accounted for 56.87. 70.43 and 78.13 % of total nitrogen excreted by P. monodon in 30, 20 and 10% respectively. DON increased to 67.26, 78.79 and 86.1% of total nitrogen excreted by the shrimp exposed to 20 mg 1-' ammonia-N in 30, 20 and 10°A, respectively. Net ammonia-N uptake occurred as shrimp were exposed to ambient ammonia-N greater than 5 mg 1-I at all salinity levels tested. Hemocyanin and protein levels decreased, whereas hemolyrnph ammonia, urea, total free amino acid levels and taurine level increased, with increased ambient ammonia-N. Following exposure to ambient ammonia-N, P. rnonodon changed its excretory pattern, accumulation of hemolymph ammonia, and catabolism of hemocyanin and protein to balance osmoregulation.

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“…The growing use of metabolic rates, such as 0 : N or 0 : P (oxygen consumed versus nitrogen or phosphorus excreted), is largely based on simple assumptions and on theoretical computations originating from mammalian catabolic data (Harris 1959, Snow & Williams 1971, Mayzaud 1973, Ikeda 1974. More recent work on the relationship between glutamate dehydrogenase (GDH) and ammonia excretion by Bidigare & King (1981) and Bidigare et al (1982) have utilized information on the pathways of zooplankton nitrogen catabolism in such calculations.…”

Section: Introductionmentioning

confidence: 99%

O:N atomic ratio as a tool to describe zooplankton metabolism

Mayzaud¹,

Conover²

1988

Mar. Ecol. Prog. Ser.

298

190

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ABSTRACT. Use of the atomic 0 : N ratio as a metabolic index requires clarification of the biochemical complexities of zooplankton intermediary metabolism. We review the processes responsible for natural and experimentally-induced changes in the ratio and discuss their relative importance in relation to a variable natural environment. During starvation the 0 : N ratio is clearly linked to the availability of energy reserves and the use of body protein. Using theoretical computations, it can be shown that pure protein catabolism will yield 0 : N ratios in the range 3 to 16, while equal amounts of lipid and protein catabolism will correspond to values between 50 and 60. Under natural feeding conditions, the value of the ratio depends on the use by the animal of each biochemical fraction assimilated. Others factors, such as seasonal events in the life cycle, biochenlical composition of the body and food quality are of importance for correct interpretation of the variations. The concepts behind the rates are discussed, suggesting that such measurements reflect the adaptability of the animals to their total environment.

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A Simple Method to Determine the O:N Ratio of Small Marine Animals

Cited by 50 publications

References 9 publications

Effects of environmental hypercapnia on animal physiology: A 13C NMR study of protein synthesis rates in the marine invertebrate Sipunculus nudus

Effects of environmental hypercapnia on animal physiology: A 13C NMR study of protein synthesis rates in the marine invertebrate Sipunculus nudus

Nitrogen excretion and changes of hemocyanin, protein and free amino acid levels in the hemolymph of Penaeus monodon exposed to different concentrations of ambient ammonia-N at different salinity levels

O:N atomic ratio as a tool to describe zooplankton metabolism

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