Quantification and inducibility of luciferase activity in transformants expressing the luciferase gene. Luciferase activity in transformants was assayed using a luminometer. The bars represent the mean of three independent experiments. The standard deviation is indicated. (A) Luciferase activity of pPsaD-GLuc-derived transformants (EuTJ…) compared to the wild-type strain. (B) Luciferase activity of pHRLucP-derived transformants (EuHR…) compared to the wild-type strain. (C) Luciferase activity of pHsp70A-GLuc-derived transformants (EuHsp…) compared to the wild-type strain. (D) Fold induction of luciferase activity in heat-shocked transformants (42°C) compared to non-heat-shocked transformants. In pPsaD-GLuc-derived transformants (EuTJ…), the luciferase gene is driven by the Chlamydomonas reinhardtii psaD promoter, and in pHRLucP-derived transformants (EuHR…), the luciferase is driven by the Volvox carteri hsp70A/rbcS3 tandem promoter. For pHsp70A-GLuc-derived transformants (EuHsp…), the luciferase gene is driven by the Chlamydomonas reinhardtii HSP70A promoter. Transformants with a gluc gene driven by a heat-inducible promoter are indicated (*). The parental wild-type strain was analyzed as a control. Transformants and wild-type colonies were subjected to a temperature shift from 27°C to 42°C for 1 h. After a 15 min recovery phase at 27°C, cells were lysed, and luciferase activity was assayed. As a reference control, non-heat-shocked transformants were analyzed in an identical fashion.