Conservation of cells, which is indispensable for regenerative medicine, now depends on freezing method. However, the freezing method has a low cell survival rate. Our idea is to preserve cells for a long time using suspended animation. Our definition of the state of cells suspended animation is state of hypometabolism followed by ATP depression, and then returned to the original state. H₂S is believed to be involved in this suspended animation process at the individual level. The objective of our project is to let the E.coli respond to the signal of the cell, and secrete the necessary amount of H₂S synthase (CTH) for the state of suspended animation to lower the metabolism. The secretion of CTH is regulated by RhlR . When the cells to be preserved become the state of suspended animation, the secretion of CTH from E.coli will stop, and most of the E.coli will also be suicided.
