Fig 4.

Transcription of norA is affected by fur. (A) β-Galactosidase activity of the S. aureus strain containing the norA-lacZ reporter fusion was determined by MUG units (1 MUG unit = 1 pmol of MUG cleaved by β-galactosidase per min per OD₆₀₀ unit). An asterisk indicates that the value is statistically different from other strains as determined by a Student's t test (P < 0.05). (B) Susceptibilities of strains to 0.8 μg/ml norfloxacin in Mueller-Hinton broth supplemented with 10 μg/ml chloramphenicol. WT/EV, wild-type Newman strain containing pYJ335 empty vector; fur/EV, fur deletion containing pYJ335; fur/p-fur, fur complementation by pYJ335::fur. The experiment was repeated in triplicates, and identical results were obtained. An asterisk indicates that the value is statistically different from other strains as determined by a Student's t test (P < 0.05).