Figure 4. Growth performance of the allele replaced mutants, and the knockout mutants at 39 °C. Growth performance was assessed by occurrence of growth in serially diluting cultures with a pre-determined number of cells at the beginning, and registering growth after 48 hours of incubation at 39 °C.

The test was repeated for four times. 10⁰, 10⁻¹ and 10⁻² represents 0, 10 and 100 times’ diluted cultures respectively. Occurrence of growth in different dilutions was indicated by “+”, and no growth was indicated by “−”. The detailed procedure is described in the Methods. *Growth occurred in the 10⁻² dilution within 24 hours.