Part:BBa_K2360010
rrnb' terminater+CadR+pCadA+SRRz+rrnb terminater
It is a high-efficiency cadmium detecting device. This device consist two parts, the lysis module (BBa_K2360000) and cadmium detecting module(BBa_K2360005).The lysis gene will be expressed when the detecting module makes a response to the metal ions, which will make bacterial cleavage, resulting in the decrease of OD600, we measured the growth curve of the engineering bacteria in different concentration of metal ions to prove its function. We can just transform the plasmid to E.coil BL21 to detect the cadmium ion.
Sequence and Features
- 10COMPATIBLE WITH RFC[10]
- 12COMPATIBLE WITH RFC[12]
- 21COMPATIBLE WITH RFC[21]
- 23COMPATIBLE WITH RFC[23]
- 25COMPATIBLE WITH RFC[25]
- 1000COMPATIBLE WITH RFC[1000]
Figure 1. Bio-circuit of BBa_K2360010
Experiment
Lysis gene expression
Our device has an obvious contact to cadmium ions’ concentration.we measured the growth curve of our engineering bacteria in different concentration of cadmium ions to prove its function.
Figure 2. the growth curve of cadmium detecting device in different concentration of cadmium ions.
As shown in the growth curves of E. coli with cadmium detecting device, the growth rate of E. coli BL21 is decline obviously after adding the concentration of Cd2+ from 10-8M to 10-5M, indicating that this device can detect the cadmium ions.
Chromogenic Reaction
Our device has an obvious contact to cadmium ions’ concentration. By detecting the shading of the product’s color, we can qualitatively detect the concentration of cadmium metals.
Figure 3. the comparison between ONPG and X-gal. b. cadmium detecting device’s chromogenic reaction at 1h 40 mins.
Specificity
We verified the detecting devices specificity of cadmium metal ions.The result indicated that the cadmium detecting device has good specificity for specific metal ions.
Figure 4. The growth of the E. coli with cadmium detecting device after adding different metal ions and ddH2O
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