Bram Van den Bergh

Stabbed while Sleeping: Synthetic Retinoid Antibiotics Kill Bacterial Persister Cells

Antibiotic-tolerant persister cells are difficult to eradicate by conventional classes of antibiotics. Kim and colleagues have discovered a new class of synthetic retinoid antibiotics that kill Staphylococcus aureus persisters by disrupting their cytoplasmic membrane.

Experimental Design, Population Dynamics, and Diversity in Microbial Experimental Evolution

In experimental evolution, laboratory-controlled conditions select for the adaptation of species, which can be monitored in real time. Despite the current popularity of such experiments, natures most pervasive biological force was long believed to be observable only on time scales that transcend a researchers life-span, and studying evolution by natural selection was therefore carried out solely by comparative means. SUMMARY In experimental evolution, laboratory-controlled conditions select for the adaptation of species, which can be monitored in real time. Despite the current popularity of such experiments, natures most pervasive biological force was long believed to be observable only on time scales that transcend a researchers life-span, and studying evolution by natural selection was therefore carried out solely by comparative means. Eventually, microorganisms propensity for fast evolutionary changes proved us wrong, displaying strong evolutionary adaptations over a limited time, nowadays massively exploited in laboratory evolution experiments. Here, we formulate a guide to experimental evolution with microorganisms, explaining experimental design and discussing evolutionary dynamics and outcomes and how it is used to assess ecoevolutionary theories, improve industrially important traits, and untangle complex phenotypes. Specifically, we give a comprehensive overview of the setups used in experimental evolution. Additionally, we address population dynamics and genetic or phenotypic diversity during evolution experiments and expand upon contributing factors, such as epistasis and the consequences of (a)sexual reproduction. Dynamics and outcomes of evolution are most profoundly affected by the spatiotemporal nature of the selective environment, where changing environments might lead to generalists and structured environments could foster diversity, aided by, for example, clonal interference and negative frequency-dependent selection. We conclude with future perspectives, with an emphasis on possibilities offered by fast-paced technological progress. This work is meant to serve as an introduction to those new to the field of experimental evolution, as a guide to the budding experimentalist, and as a reference work to the seasoned expert.