Protein Expression in the Stressed Vibrio Strains

In a conjunction process using Escherichia coli SM10 (pLOF) KmR APR as donor and Vibrio S141 SmR as recipient, several mutants were constructed: Vibrio PH 101, V. PH 106, and V. PH 109 with lowered ability to synthesize poly-beta-hydroxybutyrate. The survival and metabolic activities of parent and mutant strains were estimated when they were subjected to stress conditions (starvation of carbon and energy sources and/or cadmium treatment). Using two-dimensional electrophoresis, the synthesis of stress proteins was demonstrated. Vibrio cultures consecutively exposed to CdCl2 and then to starvation or vice versa responded similarly metabolically. These results show increased proteosynthetic activity of the stressed Vibrio cells, indicating that the primary cadmium treatment induced the expression and synthesis of the protective proteins, enabling the cells to cope with the secondary stress.