Thermolyze: A Temperature Controlled Kill-Switch for Containment of Pathogenic Bacteria in Research Labs
About This Project
We will engineer a temperature-controlled kill switch to be used in pathogenic or genetically modified bacteria as a safety precaution in lab settings. The switch design incorporates holin/antiholin lysis controlled by a temperature dependent repressible system. The system is designed to initiate lysis if temperature falls below 34C for a prolonged length of time. For this project, we will construct the kill switch in E. coli as a proof of concept for our bacteria containment system.
What is the context of this research?
Our project was initially inspired by the library of tunable temperature-sensitive promoters reported in “Tunable thermal bioswitches for in vivo control of microbial therapeutics” by Piraner and Abedi et al in 2016. Other iGEM teams in the past have attempted to develop kill-switches, but all depended on giving some chemical treatment to the bacteria in order to trigger self destruction. This is difficult to apply in real life, since in most situations where a kill switch is needed one has lost control of the bacteria, and are unable to deliver the triggering chemical treatment. Our solution to this is to use temperature itself as a trigger for the self-lysis mechanism. When bacteria with our proposed plasmid ‘escape’ the lab environment, they will die.
What is the significance of this project?
Our goal is to create a plasmid that could be used as an additional safety precaution when working in laboratory environments with dangerous pathogenic bacteria. While we are developing our construct in E. coli as a proof of concept, we envision the final product being used in species such as S. aureus that can be antibiotic resistant and are known to be susceptible to the holin/endolysin system our switch employs. For example, suppose that a team of researchers was conducting a study that was testing the effectiveness of several new chemical compounds to kill methicillin-resistant Staphylococcus aureus (MRSA). Feasibly, if improperly disposed of or tracked out by a researcher, these bacteria could escape into the outside environment and cause infection among civilians.
What are the goals of the project?
Our goal is to design, characterize, and optimize a temperature-controlled kill switch. Our switch relies on a temperature dependent repressor system to selectively express the antiholin enzyme within a narrow range of temperatures centered at 37C to correspond with typical lab conditions when working with bacteria. When the cell is outside this range for an extended period of time, antiholin is repressed leaving the holin and endolysin enzymes free to lyse the cell. This way if the bacteria ‘escapes’ it will die. Our first step is to successfully assemble our designed plasmid, then we will test it and redesign it as needed.