Advances in 13c Metabolic Flux Analysis: Co-Culture MFA and New Pathway Discovery

Measuring intracellular fluxes by ¹³C metabolic flux analysis (¹³C-MFA) has become a key activity in metabolic engineering, biotechnology and medicine. In this talk, I will present several important new advances in ¹³C-MFA that extend the scope of this technology to more complex biological systems. First, I will describe a new ¹³C-flux analysis technology that we have developed for measuring fluxes in microbial communities using GC-MS analysis. The advantages of our approach are: 1) no seperation of cells or proteins is required; 2) no genetic manipulations of cells is required; 3) no advanced analytical instruments are required; 4) we can simultaneously measure metabolic fluxes in multiple species, population dynamics, and inter-species metabolite exchange in a single step. The second ¹³C-MFA advance is the use of parallel labeling experiments for metabolic pathway discovery. In this talk, I will describe several surprising new metabolic pathways that we have discovered in central carbon metabolism in microbes, including E. coli, as well as mammalian cells. These metabolic pathways have been ”hidden” so far because they cannot be estimated using traditional tracer experiments. Only through the use of carefully selected tracers in parallel labeling experiments are we able, for the first time, to visualize these pathways. Implications of these new pathways will be discussed.