Expression profiles of the co-expression clusters whose profiles changed differently in the DTT-treated vs . non-treated recombinant cells. DTT was added at 9.5 h to bioreactor cultures of the EGI producing strain and expression analyses were performed after 30 min (10 h of culture), 1 h (10.5 h of culture) and 4 h (13.5 h of culture) of exposure. The gene expression variation of the non-treated EGI producing strain (EGI) and corresponding empty vector strain (EV) from 10 to 14 h of cultivation are shown for comparison. Dashed red squares indicate gene clusters down-regulated by DTT and green squares represent clusters up-regulated by DTT.