Team:WLC-Milwaukee/Description
Overview
Project Inspiration and Description
Team WLC-Milwaukee is from Milwaukee, Wisconsin in the United States. Milwaukee has been fighting an ongoing battle against lead poisoning for the past few years. The city has approximately 75,000 lead service lines [1] and has begun the lengthy process of replacing them with safer pipelines. Lead is a neurotoxin that is especially dangerous for children, so our team is working to make Milwaukee a safer place.
Our team chose to work on a sensor for lead contamination in water and a filter for lead to further research that would benefit the community as well as highlight the strengths of our team. The broad spectrum of methods we can use to test our project gives everyone on our growing team a chance to play a role in the development of our products.
The synthetic biology portion of the project was originally inspired by WLC-Milwaukee’s 2018 team. We considered using chromogenic enzymes coupled with synthetic biological methods to indicate lead contamination in water through color change. However, after more brainstorming, we decided to indicate the presence of lead through the sense of smell. We were also inspired by HSi Taiwan’s 2016 team because of their use of a lead affinity protein and lead-regulated promoter. This protein and promoter will play a major part in construction of a working system. Test kits are disposable and filters only last for so long; through synthetic biology, we can hopefully create a sensor that lasts longer and creates little to no waste. This is an improvement over comparable current options.
Our project has two parts. The main part is a sensor for lead contamination in water. We will be utilizing a promoter that activates a gene that expresses an enzyme that produces a wintergreen scent when lead is present. The process will have to be fine-tuned to ensure that the amount of wintergreen produced is within the threshold that anyone could detect. The unique smell of wintergreen should catch the attention of anyone testing the water and has little chance of blending into the background. The second part of our project is building a filter to specifically remove lead from water. By making use of the lead affinity like HSi Taiwan did, we aim to develop a filter that will remove lead and protect the general population from lead poisoning. We hope to accomplish both parts of our project, but will be focusing on the sensor portion, as detection of lead is a better first step than blindly filtering water that may or may not have lead.
Intro
The most common method of exposure to heavy metals is through drinking water. Milwaukee is quickly becoming a hotbed of lead contamination, especially in impoverished areas. Continuing on WLC-Milwaukee’s history of water contamination, a biosensor for lead contaminated water was developed using E. coli as a chassis for genes from Cupriavidus metallidurans.
What parts did we use?
We utilized genes from the bacterium cupriavidus metallidurans, known for its resistance to heavy metals. A segment of the plasmid of cupriavidus metallidurans has a promoter sensitive to lead. This promoter pbrR, is a negative inducible promoter which lead binds to. This means once lead binds to a site on the promoter, the promoter initiates transcription of whatever genes are downstream of the promoter.
Downstream of the promoter we attached PbrT, which aids in transferring a methyl group onto a different molecule. In this case the molecule is salicylate, which becomes methyl salicylate, the wintergreen scent.
Cupriavidus metalidurans
Cupriavidus metallidurans, a gram-negative bacterium, formed the basis for our project this year. Metallidurans, meaning metal-enduring in Latin, refers to the heavy metal resistance that the bacterium has.[2] The bacteria has been used extensively in the research of the susceptibility of different microorganisms to heavy metals.[3]
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- star_borderWe described our inspiration and plan for our project on the Project Description page, stating why this project was important and how we planned to use synthetic biology to make our idea a reality.
