Project description:In this study, the distribution and regulation of periplasmic and cytoplasmic carbon fluxes in Gluconobacter oxydans 621H with glucose were studied by 13C-based metabolic flux analysis (13C-MFA) in combination with transcriptomics and enzyme assays. For 13C-MFA, cells were cultivated with specifically 13C-labeled glucose and intracellular metabolites were analyzed for their labeling pattern by LC-MS. In growth phase I, 90% of the glucose was oxidized periplasmatically to gluconate and partially further oxidized to 2-ketogluconate. Of the glucose taken up by the cells, 9% was phosphorylated to glucose 6-phosphate, whereas 91% was oxidized by cytoplasmic glucose dehydrogenase to gluconate. Additional gluconate was taken up into the cells by transport. Of the cytoplasmic gluconate, 70% was oxidized to 5-ketogluconate and 30% was phosphorylated to 6-phosphogluconate. In growth phase II, 87% of gluconate was oxidized to 2-ketogluconate in the periplasm and 13% was taken up by the cells and almost completely converted to 6-phosphogluconate. Since G. oxydans lacks phosphofructokinase, glucose 6-phosphate can only be metabolized via the oxidative pentose phosphate pathway (PPP) or the Entner-Doudoroff pathway (EDP). 13C-MFA showed that 6-phosphogluconate is catabolized primarily via the oxidative PPP in both phase I and II (62% and 93%) and demonstrated a cyclic carbon flux through the oxidative PPP. The transcriptome comparison revealed an increased expression of PPP genes in growth phase II, which was supported by enzyme activity measurements and correlated with the increased PPP flux in phase II. Moreover, genes possibly related to a general stress response displayed increased expression in growth phase II. The transcriptome comparisons of G. oxydans growth phase II vs. growth phase I were repeated independently three times in biological replicates resulting in 3 hybridizations as termed by sample 1 to 3.
Project description:In this study, the distribution and regulation of periplasmic and cytoplasmic carbon fluxes in Gluconobacter oxydans 621H with glucose were studied by 13C-based metabolic flux analysis (13C-MFA) in combination with transcriptomics and enzyme assays. For 13C-MFA, cells were cultivated with specifically 13C-labeled glucose and intracellular metabolites were analyzed for their labeling pattern by LC-MS. In growth phase I, 90% of the glucose was oxidized periplasmatically to gluconate and partially further oxidized to 2-ketogluconate. Of the glucose taken up by the cells, 9% was phosphorylated to glucose 6-phosphate, whereas 91% was oxidized by cytoplasmic glucose dehydrogenase to gluconate. Additional gluconate was taken up into the cells by transport. Of the cytoplasmic gluconate, 70% was oxidized to 5-ketogluconate and 30% was phosphorylated to 6-phosphogluconate. In growth phase II, 87% of gluconate was oxidized to 2-ketogluconate in the periplasm and 13% was taken up by the cells and almost completely converted to 6-phosphogluconate. Since G. oxydans lacks phosphofructokinase, glucose 6-phosphate can only be metabolized via the oxidative pentose phosphate pathway (PPP) or the Entner-Doudoroff pathway (EDP). 13C-MFA showed that 6-phosphogluconate is catabolized primarily via the oxidative PPP in both phase I and II (62% and 93%) and demonstrated a cyclic carbon flux through the oxidative PPP. The transcriptome comparison revealed an increased expression of PPP genes in growth phase II, which was supported by enzyme activity measurements and correlated with the increased PPP flux in phase II. Moreover, genes possibly related to a general stress response displayed increased expression in growth phase II.
Project description:To investigate the impact of genetic and environmental factors that influence cancer cell metabolism in vivo, we conducted intra-operative 13C-glucose infusions in NSCLC patients. We determined that regional glucose metabolism was correlated with tumor perfusion as assessed by pre-surgical dynamic gadolinium enhancement. Tumors or tumor regions showing high or low perfusion were collected and subjected to RNA-seq analysis.
Project description:This dataset is part of a study aimed at developing algorithms for the quantification of stable isotope content in microorganisms after labeling them with stable isotope-labeled substrates. In this dataset Escherichia coli cultures were labeled with different percentages (1% or 10%) of either single-carbon 13C glucose (13C2) or fully-labeled 13C glucose (13C1-6). Labeled cells were subsequently mixed with unlabeled E. coli cells in fixed ratios (50%, 90%, 95%, 99%). Cultures of E. coli were grown in M9 minimal medium in which a percentage of the glucose was replaced with 13C2 or 13C1-6 glucose for >10 generations to achieve close to complete labeling of cells. Triplicate cultures were grown for each percentage. Please note that the unlabeled glucose that was used of course had a natural content of 13C of around 1.1%, thus the 0% added label samples have an actual 13C content of 1.1% and all added label is on top of this value. We included a tab delimited table with this submission providing details on all raw files.
Project description:Mammary gland (MG) de novo lipogenesis contributes significantly to milk fat in animals but little is known in humans. We hypothesized that de novo lipogenesis, as reflected by incorporation of 13C carbons from [U-13C]glucose into fatty acids (FAs) and glycerol in triglycerides (TG), will be greater: a. in milk than plasma TG, b. during a high carbohydrate (H-CHO) diet than high fat (H-FAT) diet and c. during feeding than fasting. Healthy lactating women were studied on two isocaloric, isonitrogenous diets. On one occasion subjects received diets containing H-FAT or H-CHO diet for 1 week. Incorporation of 13C from infused [U-13C]glucose into FAs and glycerol was measured using GC/MS methodology and gene expression using RNA isolated from breast milk fat globule (MFG). Incorporation of 13C2 into milk FAs, increased with increased chain length of the FAs from C2:0 to C12:0 but progressively declined in C14:0 and C16:0 and was not detected in FAs >C16. During feeding, regardless of diets, enrichment of 13C2 in milk FA and 13C3 in milk glycerol were ~3 and ~7 fold higher compared to plasma FA and glycerol, respectively. Following an overnight fast during H-CHO and H-FAT diets study periods, 25% and 6%, respectively, of medium chain FAs (MCFAs, C6-C12) were derived from glucose but increased to 75% and 25% with feeding. The expression of genes involved in FA or glycerol synthesis pathways was unchanged regardless of diet or fast-fed conditions. Conclusions: The human MG is capable of de novo lipogenesis, of primarily MCFAs and glycerol, which is influenced by the macro-nutrient composition of the maternal diet.
Project description:Mammary gland (MG) de novo lipogenesis contributes significantly to milk fat in animals but little is known in humans. We hypothesized that de novo lipogenesis, as reflected by incorporation of 13C carbons from [U-13C]glucose into fatty acids (FAs) and glycerol in triglycerides (TG), will be greater: a. in milk than plasma TG, b. during a high carbohydrate (H-CHO) diet than high fat (H-FAT) diet and c. during feeding than fasting. Healthy lactating women were studied on two isocaloric, isonitrogenous diets. On one occasion subjects received diets containing H-FAT or H-CHO diet for 1 week. Incorporation of 13C from infused [U-13C]glucose into FAs and glycerol was measured using GC/MS methodology and gene expression using RNA isolated from breast milk fat globule (MFG). Incorporation of 13C2 into milk FAs, increased with increased chain length of the FAs from C2:0 to C12:0 but progressively declined in C14:0 and C16:0 and was not detected in FAs >C16. During feeding, regardless of diets, enrichment of 13C2 in milk FA and 13C3 in milk glycerol were ~3 and ~7 fold higher compared to plasma FA and glycerol, respectively. Following an overnight fast during H-CHO and H-FAT diets study periods, 25% and 6%, respectively, of medium chain FAs (MCFAs, C6-C12) were derived from glucose but increased to 75% and 25% with feeding. The expression of genes involved in FA or glycerol synthesis pathways was unchanged regardless of diet or fast-fed conditions. Conclusions: The human MG is capable of de novo lipogenesis, of primarily MCFAs and glycerol, which is influenced by the macro-nutrient composition of the maternal diet. On day 7 of consumption of each of the two diets milk samples collected from 7 healthy, lean, exclusively breastfeeding women following an overnight fast and feeding conditions [7 x 2 x 2 = 28 samples] were processed for isotope enrichments and RNA isolation from the milk fat globules. The total RNA was utilized for microarray analyses.
Project description:October 2013 surface seawater collected from Monterey Bay was incubated with 1 micromolar 13C labeled glucose, starch, acetate, lipids, protein, or amino acids for 12 hours. Community RNA was extracted and hybridized to a Roche Nimblegen microarray and analyzed by NanoSIMS to obtain isotope ratio data for all probe spots.
Project description:Hepatic gluconeogenesis from amino acids contributes significantly to diabetic hyperglycemia, but the molecular mechanisms involved are incompletely understood. Alanine transaminases (ALT1 and ALT2) catalyze the interconversion of alanine and pyruvate, which is required for gluconeogenesis from alanine. Hepatocyte-specific knockout of Gpt2 attenuated incorporation of 13C-alanine into newly synthesized glucose by hepatocytes. However, Gpt2 knockout in liver had no effect on glucose concentrations in lean mice, which may suggest that metabolic compensation is occurring.
Project description:This dataset is part of a study aimed at developing algorithms for the quantification of stable isotope content in microorganisms after labeling them with stable isotope-labeled substrates. In this dataset Escherichia coli and Bacillus subtilis cultures were labeled with different percentages of fully labeled 13C glucose (13C6). Cultures of B. subtilis and E. coli were grown in Bacillus minimal medium or M9 minimal medium (E. coli) in which a percentage of the glucose was replaced with 13C6 glucose for >10 generations to achieve close to complete labeling of cells. The following percentages of 13C6 glucose were added 0, 0.01, 0.025, 0.1, 0.25, 1, 5 and 10%. Triplicate cultures were grown for each percentage. Please note that the unlabeled glucose that was used of course had a natural content of 13C of around 1.1%, thus the 0% added label samples have an actual 13C content of 1.1% and all added label is on top of this value. We included a tab delimited table with this submission providing details on all raw files.