A. Malmendal - Academia.edu (original) (raw)

Papers by A. Malmendal

British Journal of Nutrition, 2006

This study presents an NMR-based metabonomic approach to elucidate the overall endogenous biochem... more This study presents an NMR-based metabonomic approach to elucidate the overall endogenous biochemical effects of a wholegrain diet. Two diets with similar levels of dietary fibre and macronutrients, but with contrasting levels of wholegrain ingredients, were prepared from wholegrain rye (wholegrain diet (WGD)) and non-wholegrain wheat (non-wholegrain diet (NWD)) and fed to four pigs in a crossover design. Plasma samples were collected after 7 d on each diet, and 1 H NMR spectra were acquired on these. Partial least squares regression discriminant analysis (PLS-DA) on spectra obtained for plasma samples revealed that the spectral region at 3.25 parts per million dominates the differentiation between the two diets, as the WGD is associated with higher spectral intensity in this region. Spiking experiments and LC-MS analyses of the plasma verified that this spectral difference could be ascribed to a significantly higher content of betaine in WGD plasma samples compared with NWD samples. In an identical study with the same diets, urine samples were collected, and 1 H NMR spectra were acquired on these. PLS-DA on spectra obtained for urine samples revealed changes in the intensities of spectral regions, which could be ascribed to differences in the content of betaine and creatine/creatinine between the two diets, and LC -MS analyses verified a significantly lower content of creatinine in WGD urine samples compared with NWD urine samples. In conclusion, using an explorative approach, the present studies disclosed biochemical effects of a wholegrain diet on plasma betaine content and excretion of betaine and creatinine. NMR: Betaine: Creatinine: Wholegrain: Metabolomics * Corresponding author: Dr Hanne C. Bertram, fax þ45 89 99 15 64, email HanneC.Bertram@agrsci.dk

Molecular Nutrition & Food Research, 2009

This study presents an NMR-based metabonomic approach to explore the overall endogenous biochemic... more This study presents an NMR-based metabonomic approach to explore the overall endogenous biochemical effects of a rye versus wheat-based fiber-rich diet in hypercholesterolemic pigs. The pigs were fed high-fat, high-cholesterol rye-(n = 9) or wheat-(n = 8) based buns with similar levels of dietary fiber for 9 -10 wk. Fasting plasma samples were collected 2 days before and after 8 and 12 days on the experimental diets, while postprandial samples taken after 58 -67 days, and 1 H NMR spectra were acquired on these. Principal component analysis on the obtained NMR spectra demonstrated clear effects of diet on the plasma metabolite profile, and partial least squares regression discriminant analysis on the spectra revealed that the intensity of the spectral region at 3.29 ppm dominated the differentiation between the two diets, as the rye diet was associated with higher spectral intensity in this region. The 3.29 ppm signal is ascribed to N(CH 3 ) 3 protons in betaine, which may be an important contributor to the health promoting effects of rye.

ABSTRACT In the present study, the use of gas chromatography mass spectrometry (GC–MS)-based meta... more ABSTRACT In the present study, the use of gas chromatography mass spectrometry (GC–MS)-based metabonomics to characterize blood serum in an intervention study of patients suffering from the common gastrointestinal disorder irritable bowel syndrome (IBS) was investigated. The patients included in the study consumed an acidified milk product with (n = 30) or without probiotics (n = 31) (Lactobacillus paracasei F19, Lactobacillus acidophilus LA-5 and Bifidobacterium lactis BB-12) for an 8-week period, and blood serum samples were collected before and after the intervention. Acidified milk is commonly used as a delivering vector for probiotics in commercial consumer settings. The serum samples were extracted and derivatized using N-Methyl-N-(trimethylsilyl) trifluoroacetamide (MSTFA), and GC–MS analysis was carried out. Multivariate data analysis including principal component analysis (PCA), orthogonal partial least squares-discriminant analysis (OPLS-DA), and S-plot was applied on the obtained GC–MS data, which revealed higher serum lactate, glutamine, proline creatinine/creatine, and aspartic acid levels and lower serum glucose levels after the intervention period for both treatment groups. Consequently, the present study indicated an effect of acidified milk consumption on the plasma metabolite profile, which was independent of a concomitant intake of probiotics. In addition, the present study demonstrates that GC–MS is a useful analytical technique for metabonomics studies of blood serum.

Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, 2012

Cold tolerance and metabolic responses to freezing of three slug species common in Scandinavia (A... more Cold tolerance and metabolic responses to freezing of three slug species common in Scandinavia (Arion ater, Arion rufus and Arion lusitanicus) are reported. Autumn collected slugs were cold acclimated in the laboratory and subjected to freezing conditions simulating likely winter temperatures in their habitat. Slugs spontaneously froze at about −4°C when cooled under dry conditions, but freezing of body fluids was readily induced at −1°C when in contact with external ice crystals. All three species survived freezing for 2 days at −1°C, and some A. rufus and A. lusitanicus also survived freezing at −2°C. 1 H NMR spectroscopy revealed that freezing of body fluids resulted in accumulation of lactate, succinate and glucose. Accumulation of lactate and succinate indicates that ATP production occurred via fermentative pathways, which is likely a result of oxygen depletion in frozen tissues. Glucose increased from about 6 to 22 μg/mg dry tissue upon freezing in A. rufus, but less so in A. ater and A. lusitanicus. Glucose may thus act as a cryoprotectant in these slugs, although the concentrations are not as high as reported for other freeze tolerant invertebrates.

Analytical Chemistry, 2007

Metabonomic analysis of urine utilizing high-resolution NMR spectroscopy and chemometric techniqu... more Metabonomic analysis of urine utilizing high-resolution NMR spectroscopy and chemometric techniques has proven valuable in characterizing the biochemical response to an intervention. To assess the effect of magnetic field strength on information contained in NMR-based metabonomic data sets, 1 H NMR spectra were acquired on 250-, 400-, 500-, and 800-MHz instruments, respectively, on the same set of human urine samples collected before and after dietary interventions with milk and with meat proteins. Partial least-squares regression discriminant analyses (PLS-DA) were performed in order to elucidate the ability of the 1 H spectra acquired at various field strengths to identify possible spectral differences and discriminate between pre-and postintervention samples. The loadings from PLS-DA contained the same spectral regions, implying that the same metabolites were involved in the discrimination independent of magnetic field strength. The investigation revealed a strong increase in prediction performance and thereby spectral information content when increasing the magnetic field strength from 250 to 500 MHz, while from 500 to 800 MHz the increase was less pronounced.

... defence in myotube cultures revealed by explorative NMR-based metabonomics and proteomics Jet... more ... defence in myotube cultures revealed by explorative NMR-based metabonomics and proteomics Jette F Young*1, Lotte B Larsen1, Anders Malmendal2,3, Niels Chr Nielsen2,3, Ida K Straadt1, Niels Oksbjerg1 and Hanne C Bertram1 ...

This is the first study introducing an NMR-based metabolomic approach to elucidate metabolism in ... more This is the first study introducing an NMR-based metabolomic approach to elucidate metabolism in the portal-drained viscera and liver. High-resolution 1 H NMR spectroscopy was performed on blood plasma obtained from the mesenteric artery, the hepatic portal vein and the hepatic vein of steers before and after interruminal infusion of short-chain fatty acids (SCFA). Partial least squares regression discriminant analysis (PLS-DA) on 1 H NMR spectra obtained for arterial and portal plasma samples revealed increases in the intensities of spectral regions that could mostly be assigned to the methyl group of propionate, ␤-hydroxybutyrate as well as acetate in portal plasma samples compared with arterial plasma samples. PLS-DA on portal and hepatic plasma samples showed decreases in the intensities of spectral regions corresponding to the regions where methyl and methylene groups of n-butyrate, propionate, iso-butyrate, valerate, iso-valerate as well as lactate are reported to have chemical shifts. In addition, spectral differences likely to reflect a hepatic excretion of ␤-hydroxybutyrate and glucose were observed between portal and hepatic samples. All findings were supported by traditional biochemical analyses. Consequently, the present study clearly demonstrated the great potential of the NMR-based metabolomic approach for elucidating splanchnic metabolism. In addition, prediction of metabolite concentrations from the 1 H NMR spectra obtained on plasma samples was investigated using PLS, which in relation to use 1 H NMR spectra quantitatively revealed promising results with R-values in the region of 0.87-0.98.

AJP: Regulatory, Integrative and Comparative Physiology, 2006

Frequent exposure of terrestrial insects to temperature variation has led to the evolution of pro... more Frequent exposure of terrestrial insects to temperature variation has led to the evolution of protective biochemical and physiological mechanisms, such as the heat shock response, which markedly increases the tolerance to heat stress. Insight into such mechanisms has, so far, mainly relied on selective studies of specific compounds or characteristics or studies at the genomic or proteomic levels. In the present study, we have used untargeted NMR metabolomic profiling to examine the biological response to heat stress in Drosophila melanogaster. The metabolite profile was analyzed during recovery after exposure to different thermal stress treatments and compared with untreated controls. Both moderate and severe heat stress gave clear effects on the metabolite profiles. The profiles clearly demonstrated that hardening by moderate heat stress led to a faster reestablishment of metabolite homeostasis after subsequent heat stress. Several metabolites were identified as responsive to heat stress and could be related to known physiological and biochemical responses. The time course of the recovery of metabolite homeostasis mirrored general changes in gene expression, showing that recovery follows the same temporal pattern at these two biological levels. Finally, our data show that heat hardening permits a quicker return to homeostasis, rather than a reduction of the acute metabolic perturbation and that the reestablishment of homeostasis is important for obtaining maximal heat-hardening effect. The results display the power of NMR metabolomic profiling for characterization of the instantaneous physiological condition, enabling direct visualization of the perturbation of and return to homeostasis.

AJP: Gastrointestinal and Liver Physiology, 2013

Aquaporin 11 (AQP11) is a protein channel expressed intracellularly in multiple organs, yet its p... more Aquaporin 11 (AQP11) is a protein channel expressed intracellularly in multiple organs, yet its physiological function is unclear. Aqp11 knockout (KO) mice die early due to malfunction of the kidney, a result of hydropic degeneration of proximal tubule cells. Here we report the generation of liver-specific Aqp11 KO mice, allowing us to study the role of AQP11 protein in liver of mice with normal kidney function. The unchallenged liver-specific Aqp11 KO mice have normal longevity, their livers appeared normal, and the plasma biochemistries revealed only a minor defect in lipid handling. Fasting of the mice (24 h) induced modest dilatation of the rough endoplasmic reticulum (RER) in the periportal hepatocytes. Refeeding with standard mouse chow induced rapid generation of large RER-derived vacuoles in Aqp11 KO mice hepatocytes. Similar effects were observed following oral administration of pure protein or larger doses of various amino acids. The fasting/refeeding challenge is associated with increased expression of markers of ER stress Grp78 and GADD153 and decreased glutathione levels, suggesting that ER stress may play role in the development of vacuoles in the AQP11-deficient hepatocytes. NMR-based metabolome analysis of livers from mice subject to amino acid challenge showed decreased amount of extractable metabolites in the AQP11-deficient livers and particularly a decrease in glucose levels. In conclusion, in the liver, deletion of AQP11 results in disrupted RER homeostasis and increased sensitivity to RER injury upon metabolic challenge with amino acids.

PLoS ONE, 2012

We investigated the age-related changes in the metabolic profile of male Drosophila melanogaster ... more We investigated the age-related changes in the metabolic profile of male Drosophila melanogaster and compared the metabolic profile of flies selected for increased longevity to that of control flies of equal age. We found clear differences in metabolite composition between selection regimes and among age groups. Contrary to results found in a previous study of the transcriptome of these lines the metabolic profile did not show a younger pattern in longevity-selected (LS) flies than in same aged control (C) flies. Rather, many of the metabolites affected by age had levels common to older control individuals in the young LS flies. Furthermore, ageing affected the metabolome in a different LS specific direction. The selection induced difference increased with age. Some metabolites involved in oxidative phosphorylation changed with age highlighting the importance of mitochondrial function in the ageing process. However, these metabolites were not affected by selection for increased longevity, indicating that improvements of mitochondrial function were not involved in the increased lifespan of LS lines. Of the eight metabolites identified as having a significant difference in relative abundance between selection regimes in our study choline, lysine and glucose also show difference among lifespan phenotypes in C. elegans indicating that the correlation between the concentration of these metabolites and longevity was evolutionary conserved. Links between longevity and choline concentration is also found in mice making this metabolite an obvious target for further study. Citation: Sarup P, Pedersen SMM, Nielsen NC, Malmendal A, Loeschcke V (2012) The Metabolic Profile of Long-Lived Drosophila melanogaster. PLoS ONE 7(10): e47461.

British Journal of Nutrition, 2006

This study presents an NMR-based metabonomic approach to elucidate the overall endogenous biochem... more This study presents an NMR-based metabonomic approach to elucidate the overall endogenous biochemical effects of a wholegrain diet. Two diets with similar levels of dietary fibre and macronutrients, but with contrasting levels of wholegrain ingredients, were prepared from wholegrain rye (wholegrain diet (WGD)) and non-wholegrain wheat (non-wholegrain diet (NWD)) and fed to four pigs in a crossover design. Plasma samples were collected after 7 d on each diet, and 1 H NMR spectra were acquired on these. Partial least squares regression discriminant analysis (PLS-DA) on spectra obtained for plasma samples revealed that the spectral region at 3.25 parts per million dominates the differentiation between the two diets, as the WGD is associated with higher spectral intensity in this region. Spiking experiments and LC-MS analyses of the plasma verified that this spectral difference could be ascribed to a significantly higher content of betaine in WGD plasma samples compared with NWD samples. In an identical study with the same diets, urine samples were collected, and 1 H NMR spectra were acquired on these. PLS-DA on spectra obtained for urine samples revealed changes in the intensities of spectral regions, which could be ascribed to differences in the content of betaine and creatine/creatinine between the two diets, and LC -MS analyses verified a significantly lower content of creatinine in WGD urine samples compared with NWD urine samples. In conclusion, using an explorative approach, the present studies disclosed biochemical effects of a wholegrain diet on plasma betaine content and excretion of betaine and creatinine. NMR: Betaine: Creatinine: Wholegrain: Metabolomics * Corresponding author: Dr Hanne C. Bertram, fax þ45 89 99 15 64, email HanneC.Bertram@agrsci.dk

Molecular Nutrition & Food Research, 2009

This study presents an NMR-based metabonomic approach to explore the overall endogenous biochemic... more This study presents an NMR-based metabonomic approach to explore the overall endogenous biochemical effects of a rye versus wheat-based fiber-rich diet in hypercholesterolemic pigs. The pigs were fed high-fat, high-cholesterol rye-(n = 9) or wheat-(n = 8) based buns with similar levels of dietary fiber for 9 -10 wk. Fasting plasma samples were collected 2 days before and after 8 and 12 days on the experimental diets, while postprandial samples taken after 58 -67 days, and 1 H NMR spectra were acquired on these. Principal component analysis on the obtained NMR spectra demonstrated clear effects of diet on the plasma metabolite profile, and partial least squares regression discriminant analysis on the spectra revealed that the intensity of the spectral region at 3.29 ppm dominated the differentiation between the two diets, as the rye diet was associated with higher spectral intensity in this region. The 3.29 ppm signal is ascribed to N(CH 3 ) 3 protons in betaine, which may be an important contributor to the health promoting effects of rye.

ABSTRACT In the present study, the use of gas chromatography mass spectrometry (GC–MS)-based meta... more ABSTRACT In the present study, the use of gas chromatography mass spectrometry (GC–MS)-based metabonomics to characterize blood serum in an intervention study of patients suffering from the common gastrointestinal disorder irritable bowel syndrome (IBS) was investigated. The patients included in the study consumed an acidified milk product with (n = 30) or without probiotics (n = 31) (Lactobacillus paracasei F19, Lactobacillus acidophilus LA-5 and Bifidobacterium lactis BB-12) for an 8-week period, and blood serum samples were collected before and after the intervention. Acidified milk is commonly used as a delivering vector for probiotics in commercial consumer settings. The serum samples were extracted and derivatized using N-Methyl-N-(trimethylsilyl) trifluoroacetamide (MSTFA), and GC–MS analysis was carried out. Multivariate data analysis including principal component analysis (PCA), orthogonal partial least squares-discriminant analysis (OPLS-DA), and S-plot was applied on the obtained GC–MS data, which revealed higher serum lactate, glutamine, proline creatinine/creatine, and aspartic acid levels and lower serum glucose levels after the intervention period for both treatment groups. Consequently, the present study indicated an effect of acidified milk consumption on the plasma metabolite profile, which was independent of a concomitant intake of probiotics. In addition, the present study demonstrates that GC–MS is a useful analytical technique for metabonomics studies of blood serum.

Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, 2012

Cold tolerance and metabolic responses to freezing of three slug species common in Scandinavia (A... more Cold tolerance and metabolic responses to freezing of three slug species common in Scandinavia (Arion ater, Arion rufus and Arion lusitanicus) are reported. Autumn collected slugs were cold acclimated in the laboratory and subjected to freezing conditions simulating likely winter temperatures in their habitat. Slugs spontaneously froze at about −4°C when cooled under dry conditions, but freezing of body fluids was readily induced at −1°C when in contact with external ice crystals. All three species survived freezing for 2 days at −1°C, and some A. rufus and A. lusitanicus also survived freezing at −2°C. 1 H NMR spectroscopy revealed that freezing of body fluids resulted in accumulation of lactate, succinate and glucose. Accumulation of lactate and succinate indicates that ATP production occurred via fermentative pathways, which is likely a result of oxygen depletion in frozen tissues. Glucose increased from about 6 to 22 μg/mg dry tissue upon freezing in A. rufus, but less so in A. ater and A. lusitanicus. Glucose may thus act as a cryoprotectant in these slugs, although the concentrations are not as high as reported for other freeze tolerant invertebrates.

Analytical Chemistry, 2007

Metabonomic analysis of urine utilizing high-resolution NMR spectroscopy and chemometric techniqu... more Metabonomic analysis of urine utilizing high-resolution NMR spectroscopy and chemometric techniques has proven valuable in characterizing the biochemical response to an intervention. To assess the effect of magnetic field strength on information contained in NMR-based metabonomic data sets, 1 H NMR spectra were acquired on 250-, 400-, 500-, and 800-MHz instruments, respectively, on the same set of human urine samples collected before and after dietary interventions with milk and with meat proteins. Partial least-squares regression discriminant analyses (PLS-DA) were performed in order to elucidate the ability of the 1 H spectra acquired at various field strengths to identify possible spectral differences and discriminate between pre-and postintervention samples. The loadings from PLS-DA contained the same spectral regions, implying that the same metabolites were involved in the discrimination independent of magnetic field strength. The investigation revealed a strong increase in prediction performance and thereby spectral information content when increasing the magnetic field strength from 250 to 500 MHz, while from 500 to 800 MHz the increase was less pronounced.

... defence in myotube cultures revealed by explorative NMR-based metabonomics and proteomics Jet... more ... defence in myotube cultures revealed by explorative NMR-based metabonomics and proteomics Jette F Young*1, Lotte B Larsen1, Anders Malmendal2,3, Niels Chr Nielsen2,3, Ida K Straadt1, Niels Oksbjerg1 and Hanne C Bertram1 ...

This is the first study introducing an NMR-based metabolomic approach to elucidate metabolism in ... more This is the first study introducing an NMR-based metabolomic approach to elucidate metabolism in the portal-drained viscera and liver. High-resolution 1 H NMR spectroscopy was performed on blood plasma obtained from the mesenteric artery, the hepatic portal vein and the hepatic vein of steers before and after interruminal infusion of short-chain fatty acids (SCFA). Partial least squares regression discriminant analysis (PLS-DA) on 1 H NMR spectra obtained for arterial and portal plasma samples revealed increases in the intensities of spectral regions that could mostly be assigned to the methyl group of propionate, ␤-hydroxybutyrate as well as acetate in portal plasma samples compared with arterial plasma samples. PLS-DA on portal and hepatic plasma samples showed decreases in the intensities of spectral regions corresponding to the regions where methyl and methylene groups of n-butyrate, propionate, iso-butyrate, valerate, iso-valerate as well as lactate are reported to have chemical shifts. In addition, spectral differences likely to reflect a hepatic excretion of ␤-hydroxybutyrate and glucose were observed between portal and hepatic samples. All findings were supported by traditional biochemical analyses. Consequently, the present study clearly demonstrated the great potential of the NMR-based metabolomic approach for elucidating splanchnic metabolism. In addition, prediction of metabolite concentrations from the 1 H NMR spectra obtained on plasma samples was investigated using PLS, which in relation to use 1 H NMR spectra quantitatively revealed promising results with R-values in the region of 0.87-0.98.

AJP: Regulatory, Integrative and Comparative Physiology, 2006

Frequent exposure of terrestrial insects to temperature variation has led to the evolution of pro... more Frequent exposure of terrestrial insects to temperature variation has led to the evolution of protective biochemical and physiological mechanisms, such as the heat shock response, which markedly increases the tolerance to heat stress. Insight into such mechanisms has, so far, mainly relied on selective studies of specific compounds or characteristics or studies at the genomic or proteomic levels. In the present study, we have used untargeted NMR metabolomic profiling to examine the biological response to heat stress in Drosophila melanogaster. The metabolite profile was analyzed during recovery after exposure to different thermal stress treatments and compared with untreated controls. Both moderate and severe heat stress gave clear effects on the metabolite profiles. The profiles clearly demonstrated that hardening by moderate heat stress led to a faster reestablishment of metabolite homeostasis after subsequent heat stress. Several metabolites were identified as responsive to heat stress and could be related to known physiological and biochemical responses. The time course of the recovery of metabolite homeostasis mirrored general changes in gene expression, showing that recovery follows the same temporal pattern at these two biological levels. Finally, our data show that heat hardening permits a quicker return to homeostasis, rather than a reduction of the acute metabolic perturbation and that the reestablishment of homeostasis is important for obtaining maximal heat-hardening effect. The results display the power of NMR metabolomic profiling for characterization of the instantaneous physiological condition, enabling direct visualization of the perturbation of and return to homeostasis.

AJP: Gastrointestinal and Liver Physiology, 2013

Aquaporin 11 (AQP11) is a protein channel expressed intracellularly in multiple organs, yet its p... more Aquaporin 11 (AQP11) is a protein channel expressed intracellularly in multiple organs, yet its physiological function is unclear. Aqp11 knockout (KO) mice die early due to malfunction of the kidney, a result of hydropic degeneration of proximal tubule cells. Here we report the generation of liver-specific Aqp11 KO mice, allowing us to study the role of AQP11 protein in liver of mice with normal kidney function. The unchallenged liver-specific Aqp11 KO mice have normal longevity, their livers appeared normal, and the plasma biochemistries revealed only a minor defect in lipid handling. Fasting of the mice (24 h) induced modest dilatation of the rough endoplasmic reticulum (RER) in the periportal hepatocytes. Refeeding with standard mouse chow induced rapid generation of large RER-derived vacuoles in Aqp11 KO mice hepatocytes. Similar effects were observed following oral administration of pure protein or larger doses of various amino acids. The fasting/refeeding challenge is associated with increased expression of markers of ER stress Grp78 and GADD153 and decreased glutathione levels, suggesting that ER stress may play role in the development of vacuoles in the AQP11-deficient hepatocytes. NMR-based metabolome analysis of livers from mice subject to amino acid challenge showed decreased amount of extractable metabolites in the AQP11-deficient livers and particularly a decrease in glucose levels. In conclusion, in the liver, deletion of AQP11 results in disrupted RER homeostasis and increased sensitivity to RER injury upon metabolic challenge with amino acids.

PLoS ONE, 2012

We investigated the age-related changes in the metabolic profile of male Drosophila melanogaster ... more We investigated the age-related changes in the metabolic profile of male Drosophila melanogaster and compared the metabolic profile of flies selected for increased longevity to that of control flies of equal age. We found clear differences in metabolite composition between selection regimes and among age groups. Contrary to results found in a previous study of the transcriptome of these lines the metabolic profile did not show a younger pattern in longevity-selected (LS) flies than in same aged control (C) flies. Rather, many of the metabolites affected by age had levels common to older control individuals in the young LS flies. Furthermore, ageing affected the metabolome in a different LS specific direction. The selection induced difference increased with age. Some metabolites involved in oxidative phosphorylation changed with age highlighting the importance of mitochondrial function in the ageing process. However, these metabolites were not affected by selection for increased longevity, indicating that improvements of mitochondrial function were not involved in the increased lifespan of LS lines. Of the eight metabolites identified as having a significant difference in relative abundance between selection regimes in our study choline, lysine and glucose also show difference among lifespan phenotypes in C. elegans indicating that the correlation between the concentration of these metabolites and longevity was evolutionary conserved. Links between longevity and choline concentration is also found in mice making this metabolite an obvious target for further study. Citation: Sarup P, Pedersen SMM, Nielsen NC, Malmendal A, Loeschcke V (2012) The Metabolic Profile of Long-Lived Drosophila melanogaster. PLoS ONE 7(10): e47461.