Optimisation of Bioluminescent Reporters for Use with Mycobacteria
Figure 8
Bioluminescence correlates with cell density during exponential growth in vitro.
Cultures of M. smegmatis pMVhsp+FFluc (a), pMVhsp+Gluc (b) and pMVhsp+Lux (c) were inoculated to an optical density (OD) at 600 nm of 0.1 and the OD and the luminescence [given as relative light units (RLUs)] measured over 28 h. The luminescence was measured with integration times of 5, 0.1, and 10 s respectively, and substrate concentrations of 470 µM luciferin for FFluc and 40 µM coelenterazine for Gluc. The values represented correspond to the means of two independent cultures measured in triplicate. The error bars indicate standard deviations. A near linear relationship was found between bioluminescence [given as RLUs] and colony counts (given as colony forming units [CFU]) for mid-log cultures of M. smegmatis pMVhsp+FFluc (d), pMVhsp+Gluc (e) and pMVhsp+Lux (f) using a plate luminometer.