Part:BBa_K4765110

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

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 , 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

Figure 1. Sequencing map of LCA Sequencing is performed using the primer：Kan-F: 5-ATTCTCACCGGATTCAGT-3.

Aggregation Assay

We conducted sedimentation 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 (600μL 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 100μL 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 OD~600~ and OD~685~ measurement. The percentage of bacteria remaining in the supernatant at 6 hours was determined by dividing the bacterial count at 6 hours (as determined by the OD~600~ and OD~685~ measurement) by the bacterial count at 0 hours.

As shown in Figure 2, 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.

Figure 2. LCA 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.

Figure 3. Bacteria Percentage Remaining in the Supernatant at 6 Hours The bacterial quantity in the supernatant is quantified by measuring the OD~600~ (1 OD~600~ corresponds to 10^8 bacterial particles).

Figure 4. Bacteria Remaining in the Supernatant at 0,2,6,24 Hours The bacterial quantity in the supernatant is quantified by measuring the OD~600~ (1 OD~600~ 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