Orthogonal Quorum-Regulated Lysis for Stable Bacterial Co-Cultures
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Solution Overview
Problem
Existing methods struggle to maintain stable co-cultures of metabolically competitive bacterial strains without engineered positive or negative interactions, and there is a need for systems that can dynamically control population dynamics without exogenous input, while addressing issues of plasmid stability and selective pressure in synthetic ecosystems.
Innovation Solution
The development of orthogonal quorum-regulated lysis systems, where two bacterial strains with distinct quorum-sensing molecules and synchronized lysis circuits are co-cultured, using plasmids with lysis and activator genes under control of activatable promoters, allowing each strain to independently regulate its population without affecting the other, stabilized by toxin/antitoxin systems or actin-like protein partitioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If metabolically competitive bacterial strains are co-cultured without engineered interactions, then natural competition allows population dynamics to emerge, but stable co-culture maintenance becomes difficult
Solution Approach 1:
Each bacterial strain produces its own quorum-sensing molecule that activates lysis in a self-regulating manner. The system uses self-service mechanisms where the population density itself triggers the lysis process through quorum sensing, eliminating the need for external control or engineered cross-strain interactions to maintain stability
Solution Approach 2:
The patent divides the co-culture system into independently regulated modules, with each strain having its own quorum-sensing and lysis machinery. This segmentation allows each strain to control its own population dynamics without interfering with the other, resolving the stability issue while maintaining competitive adaptability
2Extent of automation
If quorum sensing molecules are used to regulate lysis, then population dynamics can be controlled dynamically, but cross-talk between strains may disrupt orthogonal regulation
Solution Approach 1:
The patent employs separate quorum-sensing pathways for each strain, with strain-specific molecules that do not cross-activate the other strain's lysis system. This modular segmentation enables independent automated population control for each strain while avoiding complex cross-talk interactions
Solution Approach 2:
The quorum-sensing molecules act as intermediary signals that mediate population control within each strain without directly interacting with the other strain's regulatory systems. These intermediaries enable automated control while maintaining orthogonality through strain-specific molecular recognition
3Productivity
If lysis plasmids are used to control population, then synchronized lysis can be achieved, but plasmid stability and selective pressure become problematic
Solution Approach 1:
The system incorporates feedback mechanisms where the quorum-sensing molecules provide continuous information about population density to the lysis regulation system. This feedback loop ensures synchronized lysis while the plasmid stability elements continuously monitor and maintain plasmid retention, addressing both productivity and reliability concerns
Solution Approach 2:
The patent incorporates plasmid stability elements and toxin-antitoxin systems that provide beforehand protection against plasmid loss and selective pressure. These cushioning mechanisms are built into the system architecture to prevent plasmid instability before it can affect lysis efficiency, maintaining both productivity and reliability
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables stable co-culturing of metabolically competitive strains, enhancing long-term stability and robustness of synthetic ecosystems, allowing for dynamic population control and potential applications in drug delivery and disease treatment.
Implementation Method 1
both the activatable promoter of the lysis gene and the expression of the activator gene is activated by the quorum sensing molecule
Implementation Method 2
stabilized by toxin/antitoxin systems or actin-like protein partitioning
Data Source
AI summary
Provided are bacterial strains, methods of culturing bacterial cells using synthetic quorum-regulated lysis, and uses thereof. For example, the present disclosure describes methods of maintaining a co-culture by quorum sensing. These methods comprise co-culturing at least a first bacterial strain and a second bacterial strain during a period of time of at least 12 hours.