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Demonstration of a Novel Platform For Measuring Gut Microbiome Metabolic Dynamics
Author(s) -
Wagner David,
Bolt Daniel,
Demers Melyssa,
Gruelich Knut
Publication year - 2015
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.29.1_supplement.575.26
Subject(s) - chemistry , metabolome , anaerobic exercise , feces , urea , oxalate , lactobacillus rhamnosus , microbiome , food science , stable isotope ratio , xylose , fructose , biochemistry , biology , lactobacillus , fermentation , microbiology and biotechnology , metabolite , physiology , inorganic chemistry , bioinformatics , physics , quantum mechanics
Evaluation of bacterial populations inhabiting the gut microbiome may offer insights to disease development. Further, dietary intake of carbohydrates and a Western diet may shape the metabolic dynamics of the gut microbiome. However, the ability to quantify metabolic dynamics in these bacterial populations is lacking. We developed a stable isotope tracer platform to quantify metabolic pathways based on their ability to produce 13 CO 2 from various substrates. A model system was first established using Lactobacillus rhamnosus added to a 10 ml Exetainer tube. 13 C substates in solution were then added. Samples were heated at 37°C for 4 to 12 hrs. The headspace in each tube was sampled and analyzed by gas isotope ratio mass spectrometry. We demonstrated that 13 CO 2 production from isotopically enriched solutions of glucose, fructose, acetate, pyruvate, octanoate, oxalate, and urea were able to be quantitated. Samples were tested under both aerobic and anaerobic conditions. Anaerobic conditions produced more 13 CO 2 gas. L. rhamnosus had limited ability to metabolize amino acids phenylalanine and methionine and other sugars (sorbitol, xylose and lyxose). We then used this technique to quantitate metabolic dynamics in fecal samples. After collection of fecal samples from a healthy individual, approximately 1 ml of diluted fecal samples was added to solutions of 13 C‐oxalate and 13 C‐urea. Fecal samples were heated at 37°C for 4 to 12 hrs and tested under anaerobic conditions. We demonstrated 13 CO 2 production from these substrates. When these same fecal samples were left at 22°C for 5 days, the samples continued to show enzymatic conversion to 13 CO 2 . In conclusion, we have demonstrated a simple platform for measuring metabolic dynamics of the gut microbiome in fecal samples.