23 June 2017
Markus Basan
Department of Systems Biology
Harvard Medical School
Microorganisms exhibit a myriad of phenotypes, as changes in growth rates are accompanied by large variations in metabolism, gene expression and cell size. But what gives rise to these changes and even what limits growth rate in different conditions is poorly understood. We want to understand these patterns quantitatively and make predictions. However, models for phenotypes on a cellular scale remain rare in biology, largely due to the complexity and heterogeneity of biological systems. To overcome these challenges, we start by establishing empirical relations between phenotypes across conditions. From these relations, we try to infer underlying mechanisms and construct simple models that can be tested experimentally. Concretely, I will talk about overflow metabolism in bacteria (known as the Warburg effect in higher cells) and lag phases, resulting from metabolic shifts. The theme that emerges is that fundamental tradeoffs between competing microbial objectives underlie many of the observed patterns.