Project Description
Oil sands operations in Northern Alberta bring economic prosperity to Canada. But, they also produce contaminated air, water and soil. We are in the process of transforming the nematode worm Caenorhabditis elegans into a soil bioremediation toolkit with a specific focus on naphthalene.
Wild-type C. elegans have a weak chemotaxis response to naphthalene. However, we will enhance this chemotaxis response using G-protein coupled receptors (GPCRs) found in H. sapiens, M. musculus, and R. norvegicus. Our goal is to import these foreign GPCRs into the worm under control of C. elegans neuron-specific promoters. This should produce a transgenic worm with enhanced capacity to seek out naphthalene.
We will then design a field bioassay based on our C. elegans chemotaxis system. We envision an agar plate with two populations of worms expressing different types of fluorescent protein. One population will chemotax toward naphthalene, and the other will be repulsed by naphthalene.The presence of naphthalene in a soil sample in the middle of the plate would be indicated by concentric rings of fluorescence forming around the sample.
We will also equip C. elegans with the capacity to degrade naphthalene. The NAH7 plasmid in Pseudomonas putida encodes all of the enzymes necessary break naphthalene down to pyruvate. Our ultimate goal is to bring each NAH7 gene into C. elegans under control of one of the worm’s constitutive promoters. For our project this summer, we will focus on the first enzyme in the pathway, encoded by the gene nahA. If we can demonstrate the working of this enzyme in C. elegans cells, it will provide a proof of concept that encourages further work on this pathway.
Safety Proposal
We feel confident that our project does not pose a risk to ourselves, to the public, or to the environment. C. elegans, our chassis, is not a human pathogen. Working with C. elegans carries very little risk to researchers, and BSL-1 level laboratory clearance is satisfactory for work with this organism1. Furthermore, microinjection of extrachromosomal arrays reduces the worm’s fitness. So, if a transgenic worm were to escape into the outside environment, it would be unlikely to have a selective advantage over wild-type worms. Our biobricks do not provide the worm with any selective advantages. In fact, they may reduce fitness by forcing the worm to chemotax toward naphthalene, a toxic chemical. In addition, there are a number of germline mortal C. elegans mutants. If our transgenic worm were to be used in the field, we would ensure that it contained a germline mortal mutation.
As a machine designed to chemotax toward toxic compounds, our organism poses little threat to the environment. By contrast, our organism could prove beneficial to the environment if we succeed in getting it to degrade naphthalene. By extension, our organism could also prove beneficial to human health. We feel it is unlikely that a mutation in any of our biobricks would result in harm to humans or the environment. Mutations in our biobricks would lead to deactivation of our imported GPCRs, and we would not expect this to alter the ability of the worm to survive and out-compete other organisms. Overall, C. elegans can be considered safer than E. coli, the standard synthetic biology chassis, because the worm is not capable of horizontal gene transfer.
As a machine designed to chemotax toward toxic compounds, our organism poses little threat to the environment. By contrast, our organism could prove beneficial to the environment, and by extension, human health. All our biobricks target intracelluar pathways within C. elegans. We judge it unlikely that a mutation in this kind of biobrick would result in harm to humans or the environment. Mutations in our biobricks would lead to deactivation of our imported GPCRs, and we would not expect this to alter the ability of the worm to survive and out-compete other organisms. Overall, C. elegans can be considered safer than E. coli, the standard synthetic biology chassis, because the worm is not capable of horizontal gene transfer.
Dr. Ian Chin-Sang and Kenton Ko are two of the team’s Faculty Advisors this year, and have provided the team with lab space in which we conduct all of our wet work. They are both members of the Queen’s Biohazards Committee and have ensured that we work within the appropriate biosafety regulations. Furthermore, all of our team members have undergone WHMIS and radiation safety training. Safety is one of our top priorities.
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