In order to function properly, the switch requires a termosensitive version of cI protein. As it turned out, the cI encoding brick from the registry did not contain the termosensitive mutation (verified by sequencing). The switch constructed with the wild-type cI was unfunctional, expressing only RFP, with slight variation in intensity, depending on the temperature. A point mutation has been introtuced into the completed device, in order to ensure termosensitivity of cI. As a result, a population of bacteria with new properties has been obtained. The switch expresses GFP in 30 and 37 ^oC, regardless of the presence of IPTG in the medium. In 42 ^oC on the other hand, the reporter expressed is exclusively RFP. Having been activated by high temperature, the expression of RFP continues in 30 ^oC for some time, gradually switching back to GFP. The rate of this process can be increased by an addition of IPTG.