Team:Marburg/Safety
Lab safety
Before starting our work in the laboratory, the whole group was given a safety instruction. It included all laboratory practices as described in the WHO laboratory biosafety manual, such as the hazards and risks associated with different chemicals, decontamination methods and practices, prevention of the transfer of genetic material and microorganisms. We have been following the safety protocols throughout the project, including wearing lab coats, goggles and gloves. We also got general instruction for using lab equipment.
Project Risk
Our three projects can be graded in terms of Biosafety: Pick-Up is a complete cell-free system and therefore no bigger considerations have to be made about spreading organisms into the environment. Provide delivers with the minicells a chassis which does not contain chromosomal DNA. Therefore they do not propagate anymore and live only for a limited time to produce nutrients. So this system does not constitute a risk either. Contrary to the first two subproject the project Cut Off contains the use of living and viable cells. These living cells are meant to be used inside the gut and automatically get in contact with the environment at the latest when they left the body. Using genetically modified organisms outside a laboratory environment always has a certain risk. To ensure that our CDI cells will never be able to live in the nature after they are used as therapeutic bacteria we plan to implement a killswitch.
We scanned our killswitch database for the construct that best fits our needs. We chose the killswitch designed and characterized by the Wageningen team 2014 as a draft modified with a single small change. The basic principle of this killswitch is a toggle switch that activates the toxin only if a certain inducer is present and vanishes again.
See this link to find more information on the wiki of the Wageningen team 2014: https://2014.igem.org/Team:Wageningen_UR/project/kill-switch We want to replace the promoter responding to Rhamnose by a promoter responding to the ArcA transcription factor. ArcA is part of the ArcAB two component system that regulates the metabolism depending on the level of oxygen. In anaerobic environments ArcB phosphorylates ArcA and enables binding to DNA acting as activator for gene expression.
Having implemented this killswitch with this slight modification our bacteria would be able to grow in a laboratory environment without any limitations. After the bacteria have reached the anaerobic environment of the intestine the toggle switch flips to a “ready to kill” state. When the genetically modified bacteria leave the gut and get in contact with oxygen again the toxin is expressed and the cells will die.