Physiological and Molecular Timing of the Glucose to Acetate Transition in Escherichia coli.

Brice Enjalbert,Jean-Charles Portais,Fabien Letisse

doi:10.3390/metabo3030820

Abstract

The glucose-acetate transition in Escherichia coli is a classical model of metabolic adaptation. Here, we describe the dynamics of the molecular processes involved in this metabolic transition, with a particular focus on glucose exhaustion. Although changes in the metabolome were observed before glucose exhaustion, our results point to a massive reshuffling at both the transcriptome and metabolome levels in the very first min following glucose exhaustion. A new transcriptional pattern, involving a change in genome expression in one-sixth of the E. coli genome, was established within 10 min and remained stable until the acetate was completely consumed. Changes in the metabolome took longer and stabilized 40 min after glucose exhaustion. Integration of multi-omics data revealed different modifications and timescales between the transcriptome and metabolome, but both point to a rapid adaptation of less than an hour. This work provides detailed information on the order, timing and extent of the molecular and physiological events that occur during the glucose-acetate transition and that are of particular interest for the development of dynamic models of metabolism.

Highlights

The Enterobacterium, Escherichia coli, is subjected to constant environmental variation in the intestine, especially in nutrient availability [1]
The metabolic flexibility of E. coli is extensively exploited for a broad range of biotechnological applications in which metabolism can be modified to enable the production of valuable compounds
The glucose-acetate switch is a classical model of metabolic transition in E. coli, partly because of its physiological importance [6] and partly because the production of acetate as a fermentation by-product can be a major obstacle in the development of biotechnological processes

Summary

Introduction

The Enterobacterium, Escherichia coli, is subjected to constant environmental variation in the intestine, especially in nutrient availability [1]. The capability of the bacterium to efficiently alternate nutrients, which requires the reorganization of cellular metabolism, is a fundamental advantage in the competition with other colonic microorganisms [2,3,4]. The metabolic flexibility of E. coli is extensively exploited for a broad range of biotechnological applications in which metabolism can be modified to enable the production of valuable compounds. A comprehensive understanding of the mechanisms that ensure efficient adaptation of metabolism to nutrient changes is of great interest for both basic and applied research [5]. The glucose-acetate switch is a classical model of metabolic transition in E. coli, partly because of its physiological importance [6] and partly because the production of acetate as a fermentation by-product can be a major obstacle in the development of biotechnological processes.

Results

Discussion

Conclusion