Fig 1.

Mutant construction and growth characteristics. (A) Genotype of wild-type M. acetivorans C2A, the strain capable of inducible expression via the chromosomal integration of tetR (WWM60) and the inducible MCR strain generated in this study (DDN032). (B) Growth characterization of DDN032 on high-salt trimethylamine media demonstrates a linear growth phenotype upon transfer into media lacking tetracycline (representative growth curves shown). (C) Linear growth curves of DDN032 in tetracycline-free media at various starting optical densities. Boxes 1 and 2 show details of regions used for linear regression calculations. Slopes and R² values are shown beside each line in boxes 1 and 2. (D) The slopes of the linear regressions from panel C are plotted as a function of the starting optical density, demonstrating a strong linear relationship.