Abstract

Allocation of resources to metabolic fluxes and the costly proteome reflects trade-offs between cellular functions and influences a microbe’s fitness, but our understanding of this coordinationis still limited. In Escherichia coli, an increasing anabolic, especially ribosomal, proteome fraction at faster growth correlates with a decreasing catabolic proteome fraction and a metabolic switch. However, a similar physiology cannot be observed for all microbes and many low growth rates. Our systems-level studies of the acetogen Thermoanaerobacter kivui, varying growth rates by 100x, revealed that proteome allocation is only partially controlled by growth rate, and that metabolic fluxes are primarily controlled posttranslationally. At slower growth, ribosome numbers are set by rRNA concentrations with an excess of ribosomal proteins. The catabolic proteome is uncoupled from catabolic rates as indicated by flux analysis. This research adds to our understanding of diverse ecophysiological strategies and is crucial for understanding and modelling microbial metabolism in various environments.

Biosketch

Franziska Mueller is a postdoctoral scholar at the laboratory of Prof. Alfred Spormann working on the physiology and resource allocation in thermophilic acetogenic bacteria. She earned her PhD in Biology in 2021 at the University of Münster, Germany, on the topic of biochemical, genetic, and ecological investigations on the bacterial degradation of steroid compounds. Her research focuses on the systems biology of microbes. She is fascinated by the diversity and adaptability of microbial metabolism as well as the extensive resulting interactions of microbes with their surrounding ecosystems. She believes that understanding bacterial metabolic networks and their effects is fundamental for understanding how ecosystems function and respond to changing conditions, e.g., climate change.