Targeted Colonization

Molecular Docking

For targeted nasal colonization, molecular docking identified Lp_0018 as the protein with the highest affinity for olfactory-epithelium N-acetyl heparan sulfate (NaHS).

Co-adhesion

We also achieved co-adhesion between E. coli and Lactiplantibacillus plantarum by expressing antigen--nanobody pairs (Ag2/Nb2 and Ag3/Nb3) to enhance consortium stability.

Therapeutic Module

Enzyme Expression

In the therapeutic module, we expressed 4-hydroxyphenylacetate 3-hydroxylase, glutamate--cysteine ligase, and glutathione synthetase.

Molecule Production

These enzymes boost the production of the therapeutic molecules L-DOPA and glutathione, thereby improving probiotic efficacy.

Cross-Species Communication

Quorum Sensing

For cross-species communication, we bridged the signaling divide between Gram-positive and Gram-negative bacteria by implementing both AIP- and AHL-based quorum-sensing pathways.

Bidirectional Communication

This enabled bidirectional communication between the two species and using this to regulate cooperative division of labor between L. plantarum and E. coli.

Safety Control

Kill-Switch Systems

To enhance biosafety, we designed three kill-switch systems:

• A temperature-sensitive switch for potential escape into external environments
• A hypoxia-responsive switch for escape into the intestinal environment
• An inducible emergency-shutdown system for rapid containment

Containment Mechanisms

These kill-switch systems provide multiple layers of safety control to prevent unintended release and proliferation of engineered probiotics.

Basic Parts

Composite Parts

QS Toolkit

What problem do we solve?

Because Gram-negative and Gram-positive bacteria "speak different languages"---AHLs for the former and AIPs for the latter---engineering communication between them remains difficult, which in turn constrains programmable control of synthetic consortia. Based on our literature search, as of October 7, 2025, we did not identify any published report achieving engineered, programmable bidirectional communication between Escherichia coli and Lactiplantibacillus plantarum within a single system.

What do we do?

This year, the TJUSX team developed a quorum-sensing--based, cross-species, bidirectional communication toolkit to regulate division of labor and cooperative interactions in a synthetic consortium. Signaling from Lactiplantibacillus plantarum to Escherichia coli uses an AHL channel, whereas signaling from E. coli to L. plantarum uses an AIP channel. As illustrated, the collection comprises four devices: (i) L. plantarum AHL producer, (ii) E. coli AHL sensor, (iii) E. coli AIP producer, and (iv) L. plantarum AIP sensor.

Fig.2 Schematic of our bidirectional Gram-negative/Gram-positive bacterial communication system

We completed construction and validation of this collection as a functional system and further demonstrated its practical application; additional details are available in the iGEM Registry.

Part Collection

QS Toolkit for Gram-Positive--Gram-Negative Communication