Project Inspiration and Description - The ABCs of iGEM Guelph

Project A: Antibiotic Biosensor

Antibiotic resistance is a problem that is becoming increasingly difficult to manage as more and more microbes are being exposed to antibiotics in the environment. Tetracycline is an antibiotic with a wide range of applications such as acne and sexually transmitted disease management as well as a multitude of agricultural applications. Our inspiration stems from the ever-looming threat that we face as a result of antibiotic resistance. The University of Guelph is also heavily invested in agricultural sciences.

As such, we aspire to create a time- and cost-effective diagnostic test for agricultural antibiotic runoff using Escherichia coli to yield a color change in the presence of tetracycline in the field rather than shipping samples to a lab. We chose to use the violacein pathway to produce the color change because this pathway has multiple control points that may be implemented in the future for other variables. The success of this biosensor will ideally be able to be expanded to work with other antibiotics and control mechanisms.

Project B: Beerstone

A common challenge in the beer brewing industry is the formation of calcium oxalate, which can bind with polypeptides and adhere itself to various surfaces. This buildup, commonly referred to as beerstone, is very difficult to remove. Oxalate from grains and hops combine with calcium ions from the water and other organic compounds forms calcium oxalate, an extremely insoluble precipitate. Beerstone is of concern to the industry because it damages brewing machinery, provides a medium on which bacteria grow in the form of biofilms, interferes with beer production and transportation, and can lead to unfavourable changes in the taste and appearance of beer. The cleaning methods required to combat beerstone are time consuming, expensive, and chemically intensive. The chemicals used such as nitric acid and phosphoric acid are very toxic and corrosive. Oxalate consumed in food including beer also bears harmful physiological effects on the human body, as it can react with calcium in the body to form calcium oxalate in the form of kidney stones, a painful and common medical issue. We have been inspired by the metabolism of a specific human gut microbe, Oxalobacter formigenes, which takes up and breaks down oxalate as its primary source of energy.

An expansion of one of iGEM Guelph’s previous projects, the goal of this project is to prevent the formation of calcium oxalate in the brewing process by characterizing and employing O. formigenes enzymes Formyl CoA Transferase (FRC) and Oxalyl CoA Decarboxylase (OXC) to degrade oxalate in solution. Subsequently, brewing yeast, Saccharomyces cerevisiae, will be engineered to uptake and break down oxalate using synthetic biology techniques.

Project C: CRISPR in Plants

Global warming is and has been changing weather patterns and natural systems. With changing temperatures, we have seen shifts in growing seasons, crop yield, structure, and health, as well as changes in ecological interactions with crops and their environment. With such uncertainty in both climate and weather, iGEM Guelph has recognized that from a food security and economic perspective there exists a great need to overcome these challenges. As such, we aim to genetically engineer crops to be better able to withstand the stressful conditions created by climate change.

For this project we will use Arabidopsis thaliana as a model organism for a proof of concept system to eventually be implemented as a tool in important crops. CRISPR systems will be inserted into the A. thaliana genome via Agrobacterium tumefaciens-mediated transformation in order to manipulate the expression of a select set of genes via targeting of their respective promoter regions. To decrease gene expression we will use CRISPR interference (CRISPRi), and to increase gene expression we will be employ CRISPR activation (CRISPRa).

The four initial genes of interest to be regulated are CLE18, which is responsible for root length and therefore drought response, ICE2 which regulates cold tolerance, SPCH which regulates stomatal development and DXR which regulates formation of isoprenoids and chlorophyll content.