Figure 1.

Northern analysis of the variations in TRX m, TRX h, and Fd mRNA levels in response to heavy metals. Cells were maintained in continuous light and transferred to darkness 5 h before treatment. The time of sampling is indicated at the bottom, the hours are relative to the addition of heavy metal (0 h). Autoradiographs of RNA blots from cultures supplemented with HgCl₂ (A) or CdCl₂ (C); Quantification of the corresponding northern blots (B, HgCl₂; D, CdCl₂). The final heavy-metal concentrations were 1 μm for HgCl₂ and 100 μm for CdCl₂. The probes used in each panel are indicated on the left and the sizes of the messengers on the right. PCF corresponds to the constitutive probe signal. White symbols and dashed line, Control culture; gray symbols and continuous line, treated cultures. Triangles, Fd; squares, TRX h; circles, TRX m. The mRNA levels were normalized to the constitutive probe signal. The data are the means from two to four independent experiments.