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Metabolomic investigations of American oysters using H-NMR spectroscopy.

Tikunov AP, Johnson CB, Lee H, Stoskopf MK, Macdonald JM - Mar Drugs (2010)

Bottom Line: Mitochondrial metabolism appeared most pronounced in the adductor muscle with elevated levels of carnitine facilitating ß-oxidation, and ATP, and phosphoarginine synthesis, while glycogen was elevated in the mantle/gills and stomach/digestive gland.A biochemical schematic is presented that relates metabolites to biochemical pathways correlated with physiological organ functions.This study identifies metabolites and corresponding (1)H NMR peak assignments for future NMR-based metabolomic studies in oysters.

View Article: PubMed Central - PubMed

Affiliation: Joint Department of Biomedical Engineering, NC State University and UNC Chapel Hill, Chapel Hill, NC 27599, USA. tikunov@email.unc.edu

ABSTRACT
The Eastern oyster (Crassostrea virginica) is a useful, robust model marine organism for tissue metabolism studies. Its relatively few organs are easily delineated and there is sufficient understanding of their functions based on classical assays to support interpretation of advanced spectroscopic approaches. Here we apply high-resolution proton nuclear magnetic resonance ((1)H NMR)-based metabolomic analysis to C. virginica to investigate the differences in the metabolic profile of different organ groups, and magnetic resonance imaging (MRI) to non-invasively identify the well separated organs. Metabolites were identified in perchloric acid extracts of three portions of the oyster containing: (1) adductor muscle, (2) stomach and digestive gland, and (3) mantle and gills. Osmolytes dominated the metabolome in all three organ blocks with decreasing concentration as follows: betaine > taurine > proline > glycine > ß-alanine > hypotaurine. Mitochondrial metabolism appeared most pronounced in the adductor muscle with elevated levels of carnitine facilitating ß-oxidation, and ATP, and phosphoarginine synthesis, while glycogen was elevated in the mantle/gills and stomach/digestive gland. A biochemical schematic is presented that relates metabolites to biochemical pathways correlated with physiological organ functions. This study identifies metabolites and corresponding (1)H NMR peak assignments for future NMR-based metabolomic studies in oysters.

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1H NMR spectra of the three different oyster organ blocks, scaled to the betaine peak at 3.89 ppm.
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f4-marinedrugs-08-02578: 1H NMR spectra of the three different oyster organ blocks, scaled to the betaine peak at 3.89 ppm.

Mentions: 1D 1H NMR spectra from the three dissected organ blocks of the oyster are compared in Figure 4. Three regions of the spectra (−0.5 to 3.2 ppm; 3.2 to 4.3 ppm; and 4.3 to 9.2 ppm) ranging from the aromatic (9.2 ppm) to the aliphatic (0.5 ppm) are scaled to the largest peak in that region to visualize the smaller peaks. Osmolytes have a constant ratio across the organ blocks. Therefore, these peaks (betaine, taurine, homarine, marked with asterisk (*)) were used as an internal reference in Figure 4, to calibrate the Y-scale across organ blocks (Figure 4). Figure 5 is a graph of the molar ratio (Experimental Section for calculation) of chosen metabolites in the three different extracted organ blocks. Marine mollusks, similar to other marine invertebrates, use large amounts of nitrogenous solutes, such as free amino acids and their catabolites, as the major intracellular osmolytes to protect against the high and fluctuating extracellular osmolarity of their environment [35]. Betaine and taurine, which are glycine and methionine/cysteine catabolites, respectively [9–11,20,22–24], were an order of magnitude more abundant than any other metabolite (Figure 5).


Metabolomic investigations of American oysters using H-NMR spectroscopy.

Tikunov AP, Johnson CB, Lee H, Stoskopf MK, Macdonald JM - Mar Drugs (2010)

1H NMR spectra of the three different oyster organ blocks, scaled to the betaine peak at 3.89 ppm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC2992993&req=5

f4-marinedrugs-08-02578: 1H NMR spectra of the three different oyster organ blocks, scaled to the betaine peak at 3.89 ppm.
Mentions: 1D 1H NMR spectra from the three dissected organ blocks of the oyster are compared in Figure 4. Three regions of the spectra (−0.5 to 3.2 ppm; 3.2 to 4.3 ppm; and 4.3 to 9.2 ppm) ranging from the aromatic (9.2 ppm) to the aliphatic (0.5 ppm) are scaled to the largest peak in that region to visualize the smaller peaks. Osmolytes have a constant ratio across the organ blocks. Therefore, these peaks (betaine, taurine, homarine, marked with asterisk (*)) were used as an internal reference in Figure 4, to calibrate the Y-scale across organ blocks (Figure 4). Figure 5 is a graph of the molar ratio (Experimental Section for calculation) of chosen metabolites in the three different extracted organ blocks. Marine mollusks, similar to other marine invertebrates, use large amounts of nitrogenous solutes, such as free amino acids and their catabolites, as the major intracellular osmolytes to protect against the high and fluctuating extracellular osmolarity of their environment [35]. Betaine and taurine, which are glycine and methionine/cysteine catabolites, respectively [9–11,20,22–24], were an order of magnitude more abundant than any other metabolite (Figure 5).

Bottom Line: Mitochondrial metabolism appeared most pronounced in the adductor muscle with elevated levels of carnitine facilitating ß-oxidation, and ATP, and phosphoarginine synthesis, while glycogen was elevated in the mantle/gills and stomach/digestive gland.A biochemical schematic is presented that relates metabolites to biochemical pathways correlated with physiological organ functions.This study identifies metabolites and corresponding (1)H NMR peak assignments for future NMR-based metabolomic studies in oysters.

View Article: PubMed Central - PubMed

Affiliation: Joint Department of Biomedical Engineering, NC State University and UNC Chapel Hill, Chapel Hill, NC 27599, USA. tikunov@email.unc.edu

ABSTRACT
The Eastern oyster (Crassostrea virginica) is a useful, robust model marine organism for tissue metabolism studies. Its relatively few organs are easily delineated and there is sufficient understanding of their functions based on classical assays to support interpretation of advanced spectroscopic approaches. Here we apply high-resolution proton nuclear magnetic resonance ((1)H NMR)-based metabolomic analysis to C. virginica to investigate the differences in the metabolic profile of different organ groups, and magnetic resonance imaging (MRI) to non-invasively identify the well separated organs. Metabolites were identified in perchloric acid extracts of three portions of the oyster containing: (1) adductor muscle, (2) stomach and digestive gland, and (3) mantle and gills. Osmolytes dominated the metabolome in all three organ blocks with decreasing concentration as follows: betaine > taurine > proline > glycine > ß-alanine > hypotaurine. Mitochondrial metabolism appeared most pronounced in the adductor muscle with elevated levels of carnitine facilitating ß-oxidation, and ATP, and phosphoarginine synthesis, while glycogen was elevated in the mantle/gills and stomach/digestive gland. A biochemical schematic is presented that relates metabolites to biochemical pathways correlated with physiological organ functions. This study identifies metabolites and corresponding (1)H NMR peak assignments for future NMR-based metabolomic studies in oysters.

Show MeSH