Team:ITB Indonesia/Contribution

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Contribution

New characterization to RFP Coding Device

Figure 1: There is no significant difference of mRFP expression between three strains (Bl21, DH5alpha, Top10)

Background

In Team ITB_Indonesia 2017 characterization, we found in normal growth/incubation condition (37 oC, LB agar) that BBa_J04450 -transformed Escherichia coli BL21 colony appear to need longer incubation time (>18 hours) until it clearly shows red color under natural light.

We then investigate whether this phenomenon is influenced by the strain, and we try if there are lac repressor in the system that can be released by inducing the culture with IPTG, hence increasing the expression of mRFP.

Experimental Design

We used three different strains of transformed E. coli (BL21, DH5alpha, and Top10) for this study. They were incubated in LB broth, 37 oC, and sampled every 4 hours for 2 days to determine the red color absorbance at 588 nm. The amount of IPTG added for respective treatment is 500 µM.

Result and Findings

  • There are no significant differences of mRFP expression in different strains of E. coli (BL21, DH5alpha, Top10)
  • There are no significant effects of mRFP increased expression after IPTG induction.
  • The red color absorbance under 588 nm wavelength is recorded around 2.5-3 OD units.
  • The broth become red in color under natural light around 16-20 hours of incubation time.

Figure 2: ~18 hours old mRFP-transformed E. coli strains (Right: control)
Figure 3: ~30 hours old mRFP-transformed E. coli strains (Left: control). Notice the color turn to bright purple.
Figure 4: Red color dynamics of transformed E. coli Top10 compared to control
Figure 5: Red color dynamics of transformed E. coli DH5alpha compared to control
Figure 6: Red color dynamics of transformed E. coli BL21 compared to control