FIG. 5.

GroEL is induced in PCB-degrading bacteria during growth with different CBs. Pseudomonas sp. strain B4 cells were shifted from a defined medium supplemented with glucose to a medium supplemented with biphenyl (▴), 2-chlorobiphenyl (▵), or 4-chlorobiphenyl (▪) as the sole carbon source. Control cells were maintained in the presence of glucose (•) or were subjected to heat shock at 42°C (□) for different times. The growth of the shifted cells was determined by measuring the optical density at 600 nm during the experiment. The only cells that grew during the experiment were the control cells grown with glucose. Cell extracts from the cells shifted to the different conditions were used to determine the levels of GroEL by Western blotting after separation of the total proteins by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Quantitation of the GroEL bands after Western blotting was done by using an image analysis program (Scion Image).