fumarates and fructose-1-6-diphosphate

Dental caries is initiated by demineralization of the tooth surface through acid production by sugar metabolism of supragingival plaque microflora. To elucidate the sugar metabolic system, we used CE-MS to perform metabolomics of the central carbon metabolism, the EMP pathway, the pentose-phosphate pathway, and the TCA cycle in supra- gingival plaque and representative oral bacteria, Streptococcus and Actinomyces. Supragingival plaque contained all the targeted metabolites in the central carbon metabolism, except erythrose 4-phosphate in the pentose-phosphate pathway. After glucose rinse, glucose 6-phosphate, fructose 6-phosphate, fructose 1,6-bisphosphate, dihydroxyacetone phosphate, and pyruvate in the EMP pathway and 6-phosphogluconate, ribulose 5-phosphate, and sedoheptulose 7-phosphate in the pentose-phosphate pathway, and acetyl CoA were increased. Meanwhile, 3-phosphoglycerate and phosphoenolpyruvate in the EMP pathway and succinate, fumarate, and malate in the TCA cycle were decreased. These pathways and changes in metabolites observed in supragingival plaque were similar to the integration of metabolite profiles in Streptococcus and Actinomyces.

Topics: Acetyl Coenzyme A; Actinomyces; Adult; Bacteriological Techniques; Carbon; Citric Acid Cycle; Dental Plaque; Dihydroxyacetone Phosphate; Female; Fructosediphosphates; Fructosephosphates; Fumarates; Gluconates; Glucose; Glucose-6-Phosphate; Glyceric Acids; Glycolysis; Humans; Malates; Male; Metabolomics; Pentose Phosphate Pathway; Phosphoenolpyruvate; Pyruvic Acid; Ribulosephosphates; Streptococcus; Streptococcus mutans; Succinic Acid; Sugar Phosphates

The extent to and the mechanism by which fructose-1,6-bisphosphate (FDP) crosses cell membranes are unknown. We hypothesized that its transport is either via band 3 or a dicarboxylate transporter. The question was addressed in isolated Langendorff rat hearts perfused under normoxic conditions. Groups of hearts received the following metabolic substrates (in mM): 5 FDP; 5 FDP + either 5, 10, or 20 fumarate; 10 FDP and either 5, 10, or 20 fumarate; or 5 FDP + 2 4,4'-dinitrostilbene-2,2'-disulfonate (DNDS), a band 3 inhibitor. FDP uptake and metabolism were measured as production of [(13)C]lactate from [(13)C]FDP or (14)CO(2) and [(14)C]lactate from uniformly labeled [(14)C]FDP in sample perfusates. During 30 min of perfusion, FDP metabolism was 12.4 +/- 2.6 and 31.2 +/- 3.0 micromol for 5 and 10 mM FDP, respectively. Addition of 20 mM fumarate reduced FDP metabolism over a 30-min perfusion period to 3.1 +/- 0.6 and 6.3 +/- 0.5 micromol for 5 and 10 mM FDP groups, respectively. DNDS did not affect FDP utilization. These data are consistent with transport of FDP by a dicarboxylate transport system.

Topics: Animals; Anion Exchange Protein 1, Erythrocyte; Biological Transport; Carbon Dioxide; Carbon Radioisotopes; Dicarboxylic Acid Transporters; Energy Metabolism; Fructosediphosphates; Fumarates; Glycolysis; Hydrogen-Ion Concentration; Lactic Acid; Magnetic Resonance Spectroscopy; Myocardial Ischemia; Myocardium; Rats; Sarcolemma