Fig. 3From: Development of an auto-inducible expression system by nitrogen sources switching based on the nitrogen catabolite repression regulationEffect of NO3− and NH4+ concentrations on the auto-inducible expression system. a Confirmation of the utilization order of NO3− and NH4+. b Biomass of A.n-PniaD-gusA under difference of NO3−/NH4+. c GUS activity under difference of NO3−/NH4+Back to article page