Evolution experiments were inoculated with ancestral colonies of IS+ and IS- strains grown in 3 ml of LB medium over night, after two washing steps in M9 medium without carbon source (M9 buffer) and a dilution of 1:200.
Bacterial cultures were grown in 200 µl liquid evolution medium with the indicated galactose concentrations in clear flat-bottom 96-well plates and shaken in a Titramax plateshaker at 750 rpm (Heidolph, Schwabach, Germany), allowing for a total population size of ~108 colony forming units for the ancestral strain. Every day, populations were transferred to fresh plates using a VP408 pin replicator (V&P SCIENTIFIC, Inc, San Diego, CA) resulting in a dilution of ~1:820 (Steinrueck and Guet, 2017 (link)), corresponding to ~10 generations. Immediately after the transfer, growth and fluorescence measurements were performed in the overnight plates using a Biotek H1 plate reader (Biotek, Vinooski, Vermont). Thus, population phenotypes were measured every 10 generations.
Bacterial cultures were grown in 200 µl liquid evolution medium with the indicated galactose concentrations in clear flat-bottom 96-well plates and shaken in a Titramax plateshaker at 750 rpm (Heidolph, Schwabach, Germany), allowing for a total population size of ~108 colony forming units for the ancestral strain. Every day, populations were transferred to fresh plates using a VP408 pin replicator (V&P SCIENTIFIC, Inc, San Diego, CA) resulting in a dilution of ~1:820 (Steinrueck and Guet, 2017 (link)), corresponding to ~10 generations. Immediately after the transfer, growth and fluorescence measurements were performed in the overnight plates using a Biotek H1 plate reader (Biotek, Vinooski, Vermont). Thus, population phenotypes were measured every 10 generations.
Free full text: Click here
