Detection of luciferase activity by in-gel activity assays. The transformants PanHR-11 and PanHsp-4 were generated with the co-bombarded plasmids pHRLucP and pHsp70A-GLuc, respectively. The wild-type strain was used as a control. Algae cultures were divided into two aliquots; one aliquot was subjected to a heat shock at 39°C for 1 h, and the other aliquot was maintained at 29°C. Cell extracts with equal amounts of protein were subjected to SDS-PAGE. Subsequently, in-gel renaturation was performed using β-cyclodextrin to remove SDS from the gel, the coelenterazine-substrate was added, and the gel was exposed to a light-sensitive film (right panel). As a loading control, the same extracts were also stained with Coomassie Blue following SDS-PAGE (left panel).