Reductase activity in cellular fractions. (A) Cell lysate of strain E1 grown without prior exposure to K2TeO3. Similar results were found for KR99, E5, RB3, and RB 16-17; (B) Lysate of strain E4(1) grown without prior exposure to K2TeO3; (C) Lysate of E4(1) cells grown with prior exposure to K2TeO3. Initial darkening at 0 h is due to the trace presence of previously reduced K2TeO3 from prior exposure; (D) Periplasmic fraction of KR99 without K2TeO3 exposure. No reductase activity observed. Similar results for E5, E4(1), E1, RB3 and RB 16-17; (E) Spheroplast fraction of E1 without prior K2TeO3 exposure containing reductase activity. Similar results for E5, KR99, RB3, and RB 16-17; (F) Spheroplast lysate of KR99 without prior K2TeO3 exposure containing reductase activity. Similar results for E5, E1, RB3, and RB 16-17; (G) E4(1) spheroplast fraction. No reductase activity observed with or without prior K2TeO3 exposure; (H) E4(1) spheroplast lysate. No reductase activity observed with or without prior K2TeO3 exposure.