title: Fitness as a function of beta-galactosidase activity in Escherichia coli.
mesh_terms: D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics / Q000254:growth & development*; D005696:Galactosidases / Q000378:metabolism*; D009154:Mutation; D012641:Selection, Genetic; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism*
chemical_list: D005696:Galactosidases; D001616:beta-Galactosidase