Luciferase activity in purified GVNPs from Halobacterium sp. NRC-1∆ ura 3∆ gvp C and Halobacterium sp. NRC-1 strains containing gvp C and luciferase expression plasmids. Percent luciferase activity, chemiluminescence activity detected in gas vesicles compared to the total activity observed in cell lysates, is plotted on vertical axis for pDRK-C-L plasmid series. Values plotted are the average of experiments performed in triplicate, and standard deviation shown with error bars. A: pDRK-C1-L, B: pDRK-C2-L, C: pDRK-C3-L, D: pDRK-C4-L in either Halobacterium sp. NRC-1Δura3ΔgvpC (blue), or in wild-type Halobacterium sp. NRC-1 (pink) strain.