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2-Deoxy-2-fluoro-d-glucose metabolism in Arabidopsis thaliana.

Fatangare A, Paetz C, Saluz H, Svatoš A - Front Plant Sci (2015)

Bottom Line: We fed FDG to leaf tissue and analyzed leaf extracts using MS and NMR.Glycolysis and starch degradation seemed to be the important pathways for FDG metabolism.We showed that FDG metabolism in plants is considerably different than animal cells and goes beyond FDG-phosphate as previously presumed.

View Article: PubMed Central - PubMed

Affiliation: Mass Spectrometry/Proteomics Research Group, Max Planck Institute for Chemical Ecology Jena, Germany.

ABSTRACT
2-Deoxy-2-fluoro-d-glucose (FDG) is glucose analog routinely used in clinical and animal radiotracer studies to trace glucose uptake but it has rarely been used in plants. Previous studies analyzed FDG translocation and distribution pattern in plants and proposed that FDG could be used as a tracer for photoassimilates in plants. Elucidating FDG metabolism in plants is a crucial aspect for establishing its application as a radiotracer in plant imaging. Here, we describe the metabolic fate of FDG in the model plant species Arabidopsis thaliana. We fed FDG to leaf tissue and analyzed leaf extracts using MS and NMR. On the basis of exact mono-isotopic masses, MS/MS fragmentation, and NMR data, we identified 2-deoxy-2-fluoro-gluconic acid, FDG-6-phosphate, 2-deoxy-2-fluoro-maltose, and uridine-diphosphate-FDG as four major end products of FDG metabolism. Glycolysis and starch degradation seemed to be the important pathways for FDG metabolism. We showed that FDG metabolism in plants is considerably different than animal cells and goes beyond FDG-phosphate as previously presumed.

No MeSH data available.


Related in: MedlinePlus

1H-decoupled 19F-NMR spectra of fractions containing fluorinated metabolites including chemical shifts. Signals are referenced to C6F6 at δF -164.9. (A) Raw extract of A. thaliana after FDG administration before separation. The two most intense signals belong to α-FDG (δF − 197.63) and β-FDG (δF − 197.52). (B) Fraction containing the fluorinated compound α/β-FDG-6-P (m/z 261.0180). The α-isomer shows a chemical shift of δF − 197.75, the β-isomer resonates at δF − 197.55. (C) Fraction containing the fluorinated compound α/β-F-maltose (m/z 343.1051). The compound shows signals that appear most deep-field shifted among the identified metabolites (α: δF − 198.50, β: δF − 198.26). (D) Fraction assumed to contain a fluorinated derivative of gluconic acid (m/z 197.0464). The signals indicated likely represent impurities from compounds α/β-FDG-6-P and α/β-F-Maltose.
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Figure 2: 1H-decoupled 19F-NMR spectra of fractions containing fluorinated metabolites including chemical shifts. Signals are referenced to C6F6 at δF -164.9. (A) Raw extract of A. thaliana after FDG administration before separation. The two most intense signals belong to α-FDG (δF − 197.63) and β-FDG (δF − 197.52). (B) Fraction containing the fluorinated compound α/β-FDG-6-P (m/z 261.0180). The α-isomer shows a chemical shift of δF − 197.75, the β-isomer resonates at δF − 197.55. (C) Fraction containing the fluorinated compound α/β-F-maltose (m/z 343.1051). The compound shows signals that appear most deep-field shifted among the identified metabolites (α: δF − 198.50, β: δF − 198.26). (D) Fraction assumed to contain a fluorinated derivative of gluconic acid (m/z 197.0464). The signals indicated likely represent impurities from compounds α/β-FDG-6-P and α/β-F-Maltose.

Mentions: The exact structure and phosphorylation site of FDG-X-P (m/z 261.0180) remained unclear. The semi-purified sample was thus subjected to extensive NMR analysis. 19F-NMR spectroscopy revealed FDG-X-P as the most abundant metabolite in the extract, showing two signals at δF -197.75 (α-FDG-X-P) and δF − 197.55 (β-FDG-X-P) (Figure 2). The assignment is based on the fact that chemical shift values for α-isomers appear generally shifted toward deeper field compared to the corresponding β-isomers (Southworth et al., 2003). It has to be noted that determined chemical shifts are not in accordance with the literature, which might be either caused by impurities present in the samples and/or due to concentration-dependend shifting. Structure elucidation was therefore based on 1H-1H and 1H-13C correlation experiments. Characteristic correlations in the 1H-1H dqfCOSY spectrum (Supplementary Figure 6) revealed the signals of position 1 at δH 5.29 (d, 3JHH = 3.8) (H-1α) and δH 4.76 (dd, 3JHH = 7.8/3JHF = 2.0) (H-1β), respectively. According to corresponding signals in the 1H-13C HSQC spectrum, the 13C chemical shifts were assigned to δC 89.6 (d, 2JCF = 21.2) (C-1α) and δC 93.5 (d, 2JCF = 23.6) (C-1β). Since the 1H- and 13C-NMR spectra were recorded without 31P- and 19F-decoupling, the extracted coupling patterns revealed the presence of FDG-6-P.


2-Deoxy-2-fluoro-d-glucose metabolism in Arabidopsis thaliana.

Fatangare A, Paetz C, Saluz H, Svatoš A - Front Plant Sci (2015)

1H-decoupled 19F-NMR spectra of fractions containing fluorinated metabolites including chemical shifts. Signals are referenced to C6F6 at δF -164.9. (A) Raw extract of A. thaliana after FDG administration before separation. The two most intense signals belong to α-FDG (δF − 197.63) and β-FDG (δF − 197.52). (B) Fraction containing the fluorinated compound α/β-FDG-6-P (m/z 261.0180). The α-isomer shows a chemical shift of δF − 197.75, the β-isomer resonates at δF − 197.55. (C) Fraction containing the fluorinated compound α/β-F-maltose (m/z 343.1051). The compound shows signals that appear most deep-field shifted among the identified metabolites (α: δF − 198.50, β: δF − 198.26). (D) Fraction assumed to contain a fluorinated derivative of gluconic acid (m/z 197.0464). The signals indicated likely represent impurities from compounds α/β-FDG-6-P and α/β-F-Maltose.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4630959&req=5

Figure 2: 1H-decoupled 19F-NMR spectra of fractions containing fluorinated metabolites including chemical shifts. Signals are referenced to C6F6 at δF -164.9. (A) Raw extract of A. thaliana after FDG administration before separation. The two most intense signals belong to α-FDG (δF − 197.63) and β-FDG (δF − 197.52). (B) Fraction containing the fluorinated compound α/β-FDG-6-P (m/z 261.0180). The α-isomer shows a chemical shift of δF − 197.75, the β-isomer resonates at δF − 197.55. (C) Fraction containing the fluorinated compound α/β-F-maltose (m/z 343.1051). The compound shows signals that appear most deep-field shifted among the identified metabolites (α: δF − 198.50, β: δF − 198.26). (D) Fraction assumed to contain a fluorinated derivative of gluconic acid (m/z 197.0464). The signals indicated likely represent impurities from compounds α/β-FDG-6-P and α/β-F-Maltose.
Mentions: The exact structure and phosphorylation site of FDG-X-P (m/z 261.0180) remained unclear. The semi-purified sample was thus subjected to extensive NMR analysis. 19F-NMR spectroscopy revealed FDG-X-P as the most abundant metabolite in the extract, showing two signals at δF -197.75 (α-FDG-X-P) and δF − 197.55 (β-FDG-X-P) (Figure 2). The assignment is based on the fact that chemical shift values for α-isomers appear generally shifted toward deeper field compared to the corresponding β-isomers (Southworth et al., 2003). It has to be noted that determined chemical shifts are not in accordance with the literature, which might be either caused by impurities present in the samples and/or due to concentration-dependend shifting. Structure elucidation was therefore based on 1H-1H and 1H-13C correlation experiments. Characteristic correlations in the 1H-1H dqfCOSY spectrum (Supplementary Figure 6) revealed the signals of position 1 at δH 5.29 (d, 3JHH = 3.8) (H-1α) and δH 4.76 (dd, 3JHH = 7.8/3JHF = 2.0) (H-1β), respectively. According to corresponding signals in the 1H-13C HSQC spectrum, the 13C chemical shifts were assigned to δC 89.6 (d, 2JCF = 21.2) (C-1α) and δC 93.5 (d, 2JCF = 23.6) (C-1β). Since the 1H- and 13C-NMR spectra were recorded without 31P- and 19F-decoupling, the extracted coupling patterns revealed the presence of FDG-6-P.

Bottom Line: We fed FDG to leaf tissue and analyzed leaf extracts using MS and NMR.Glycolysis and starch degradation seemed to be the important pathways for FDG metabolism.We showed that FDG metabolism in plants is considerably different than animal cells and goes beyond FDG-phosphate as previously presumed.

View Article: PubMed Central - PubMed

Affiliation: Mass Spectrometry/Proteomics Research Group, Max Planck Institute for Chemical Ecology Jena, Germany.

ABSTRACT
2-Deoxy-2-fluoro-d-glucose (FDG) is glucose analog routinely used in clinical and animal radiotracer studies to trace glucose uptake but it has rarely been used in plants. Previous studies analyzed FDG translocation and distribution pattern in plants and proposed that FDG could be used as a tracer for photoassimilates in plants. Elucidating FDG metabolism in plants is a crucial aspect for establishing its application as a radiotracer in plant imaging. Here, we describe the metabolic fate of FDG in the model plant species Arabidopsis thaliana. We fed FDG to leaf tissue and analyzed leaf extracts using MS and NMR. On the basis of exact mono-isotopic masses, MS/MS fragmentation, and NMR data, we identified 2-deoxy-2-fluoro-gluconic acid, FDG-6-phosphate, 2-deoxy-2-fluoro-maltose, and uridine-diphosphate-FDG as four major end products of FDG metabolism. Glycolysis and starch degradation seemed to be the important pathways for FDG metabolism. We showed that FDG metabolism in plants is considerably different than animal cells and goes beyond FDG-phosphate as previously presumed.

No MeSH data available.


Related in: MedlinePlus