Composite
Lac sensor

Part:BBa_K2292005

Designed by: CHENG-HAO LEE   Group: iGEM17_CCU_Taiwan   (2017-10-26)
Revision as of 00:44, 2 November 2017 by Max25244021 (Talk | contribs)


Lactate detection

Our project aims to detect the risk of caries through three parameters: Competence stimulating peptide, CSP concentration, lactate level, pH value.

This construction is used for lactate quantization We made use of the property of LldR operon. The LldR is transcription factor. Without lactate, it will bind on O1&O2 operator site, form a DNA loop, blocking the transcription. As lactate present, lactate will bind on LldR and open the loop, allowing the transcription to go on and produce GFP. GFP intensity is then detected and deduct lactate level. This construction is cloned into E.coli.

Lac~bla23.jpg

Figure 1 Mechanism of lactate detection

O1 and O2 binding is added on two sides of promoter(J23118)

Sequence:

O1: AATTGGCCCTACCAATT O2: AATTGGCAGTGCCACTT


Agarose_gel_electrophoresis_of_LldR_detection_system.jpg

Figure 2 1 % Agarose, 100V. Check the size of assemble [pSB1A2 (2079 bp)]-[O1-J23118-O2-GFP-J23118-LldR (2241 bp)].

After finished assambling our parts, we did some function test, to find the relationship between GFP expression and lactate level.

Fluorescence_of_each_lactate_concentration_depends_on_time.jpg

Figure 3 Fluorescence of each lactate concentration depends on time.

We found that even though fluorescence in each concentration of lactate are floating, the spacing of each data are stable expect data 10 mM. It seems to be saturated when lactate concentration reaches 8 mM.

Fluorescence_of_different_time_depends_on_lactate_level.jpg

Figure 4 Fluorescence of different time depends on lactate level.

The interval 120 minute ≤ time ≤210 minute, the fluorescence of each concentration of lactate is similarity. Positive correlation exists between fluorescence and concentration of lactate on an interval 120 minute ≤ time ≤270 minute.

Combine_Figure_4_and_Figure_5_together.jpg

Figure 5 Combine Figure 4 and Figure 5 together.

We found that fluorescence level was high at the beginning. The general trend of fluorescence became pronounced and stable as time goes by.


Sequence and Features


Assembly Compatibility:
  • 10
    COMPATIBLE WITH RFC[10]
  • 12
    INCOMPATIBLE WITH RFC[12]
    Illegal NheI site found at 7
    Illegal NheI site found at 30
    Illegal NheI site found at 993
    Illegal NheI site found at 1016
  • 21
    COMPATIBLE WITH RFC[21]
  • 23
    COMPATIBLE WITH RFC[23]
  • 25
    INCOMPATIBLE WITH RFC[25]
    Illegal AgeI site found at 628
  • 1000
    INCOMPATIBLE WITH RFC[1000]
    Illegal BsaI.rc site found at 1691


[edit]
Categories
//cds/reporter/gfp
Parameters
chassisE. coli