Universal scaling relation and criticality in metabolism and growth of Escherichia coli

TL;DR

This study uncovers universal scaling laws and criticality in Escherichia coli's metabolism, revealing a balance between growth and adaptation that enhances survival in changing environments.

Contribution

It introduces a maximum entropy framework to demonstrate universality and criticality in bacterial metabolism across different conditions, a novel insight into bacterial growth regulation.

Findings

Universal scaling relations in metabolic networks

E. coli metabolism operates near maximum Fisher information

Criticality enhances sensitivity and adaptability

Abstract

The metabolic network plays a crucial role in regulating bacterial metabolism and growth, but it is subject to inherent molecular stochasticity. Previous studies have utilized flux balance analysis and the maximum entropy method to predict metabolic fluxes and growth rates, while the underlying principles governing bacterial metabolism and growth, especially the criticality hypothesis, remain unclear. In this study, we employ a maximum entropy approach to investigate the universality in various constraint-based metabolic networks of Escherichia coli. Our findings reveal the existence of universal scaling relations across different nutritional environments and metabolic network models, similar to the universality observed in physics. By analyzing single-cell data, we confirm that metabolism of Escherichia coli operates close to the state with maximum Fisher information, which serves as a signature of criticality. This critical state provides functional advantages such as high sensitivity and long-range correlation. Moreover, we demonstrate that a metabolic system operating at criticality takes a compromise solution between growth and adaptation, thereby serving as a survival strategy in fluctuating environments.