DNA

Part:BBa_K4765110

Designed by: Siliang Zhan   Group: iGEM23_Fudan   (2023-09-30)
Revision as of 15:51, 12 October 2023 by Zhe Dong (Talk | contribs)

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Twister P1 + T7_RBS + intimin-LCA fusion + stem-loop

contributed by Fudan iGEM 2023

Introduction

We’ve developed an E. coli-cyanobacteria adhesion module by transfecting intimin-LCA fusion. Intimin-LCA fusion is composed of intimin and LCA. LCA is a lectin from Lentils that can recognize α-linked mannose residues. It is a common lectin that can specifically bind to the LPS on the surface of S. elongatus PCC7942. Intimin includes a short N-terminal signal peptide to direct its trafficking to the periplasm, a LysM domain for peptidoglycan binding, and a beta-barrel for transmembrane insertion[1] , possesses the outer membrane anchoring of LCA.

Usage and Biology

This biological component delivers LCA to the surface of E. coli, facilitating adhesion between E. coli, and S. elongatus PCC7942. We envision that the adhesion between cyanobacteria and E. coli can promote the exchange of substances within the biofilm, enhancing the biofilm's survivability.

Characterization

Sequencing map

contributed by Fudan iGEM 2023
Figure 1. Sequencing map of LCA

Sequencing is performed using the primer:Kan-F: 5-ATTCTCACCGGATTCAGT-3.

Successful Protein Expression

contributed by Fudan iGEM 2023
Figure 2. SDS-PAGE electrophoresis of intimin-LCA

We constructed intimin-LCA into the pDSG plasmid and transformed it into E. coli DH5α. Lane 1 to 2 represent intimin-LCA and intimin-LCA + aTc. As indicated by the red arrow, we successfully expressed intimin-LCA.

Aggregation Assay

We conducted aggregation experiments to validate intimin-LCA's role in mediating the binding of E.coli and Synechococcus elongatus. Specifically, bacterial solutions of aTc-induced/not-induced intimin-LCA E.coli + Synechococcus elongatus, were mixed in a 1:1 ratio (600 μL per strain per tube, independent experiment repeat 3 times) and allowed to settle. Sampling was performed at 0, 2, 6, and 24 hours by collecting 100 μL aliquots from the upper 25% of each mixture (supernatant) in each tube at each time point. These samples were transferred to EP tubes and stored at 4 ℃ until the final sampling. Afterward, they were resuspended and transferred to a 96-well assay plate for OD600 and OD685 measurements. The percentage of bacteria remaining in the supernatant at 6 hours was determined by dividing the bacterial count at 6 hours (as quantified by the OD600 and OD685 measurements) by the bacterial count at 0 hours.

As shown in Figure 3, at 6 hours, in the aTc-induced E. coli / Synechococcus elongatus samples, the bacteria percentage remaining in the supernatant was significantly lower compared to the uninduced samples. As shown in Figure 3, For aTc-induced intimin-LCA E.coli / Synechococcus elongatus mixed samples, the bacterial count at 6 hours and 24 hours was significantly lower than the uninduced type. These results suggest that intimin-LCA can facilitate the binding between the two entities and promote biofilm formation.

contributed by Fudan iGEM 2023
Figure 3. E. coli-Synechococcus elongatus Aggregation Result

To make results more apparent, we added red fluorescent protein mScarlet after intimin-LCA. After mixing E. coli expressing intimin-LCA with Synechococcus elongatus for 6 hours, significant aggregation can be observed, as indicated by the red arrow in the image.

contributed by Fudan iGEM 2023
Figure 4. Bacteria Percentage Remaining in the Supernatant at 6 Hours

The bacterial quantity in the supernatant is quantified by measuring the OD600 (1 OD600 corresponds to 10^8 bacterial particles).

contributed by Fudan iGEM 2023
Figure 5. Bacteria Remaining in the Supernatant at 0,2,6,24 Hours

The bacterial quantity in the supernatant is quantified by measuring the OD600 (1 OD600 corresponds to 10^8 bacterial particles).

Sequence and Features


Assembly Compatibility:
  • 10
    COMPATIBLE WITH RFC[10]
  • 12
    COMPATIBLE WITH RFC[12]
  • 21
    COMPATIBLE WITH RFC[21]
  • 23
    COMPATIBLE WITH RFC[23]
  • 25
    COMPATIBLE WITH RFC[25]
  • 1000
    INCOMPATIBLE WITH RFC[1000]
    Illegal BsaI site found at 1305


Reference

  1. Piñero-Lambea, C., Bodelón, G., Fernández-Periáñez, R., Cuesta, A. M., Álvarez-Vallina, L., & Fernández, L. Á. (2015). Programming controlled adhesion of E. coli to target surfaces, cells, and tumors with synthetic adhesins. ACS Synthetic Biology, 4(4), 463–473. https://doi.org/10.1021/sb500252a
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Categories
//collections/biofilm
Parameters
protein