Welcome to Nova Scotia Canada’s famous East Coast! Here our lakes and
rivers play an important part as natural resources for the province.
While we strive to take care of these waters environmentally they continue
to be plagued by the acid rain byproduct aluminum. The aluminum present in
these waters causes aluminum toxicity leading to many different problems
such as reduced salmon populations. The current solutions to reducing
aluminum toxicity are expensive and therefore not practical for regular
water testing. That’s where we come in!
Our team set out to develop an inexpensive test kit to allow for regular
water testing to determine when action against aluminum toxicity is required.
We found an aluminum loving siderophore, pyoverdine,produced by the bacteria Pseudomonas fluorescens. Pyoverdine fluoresces within the visible spectrum when bound to Al3+ ions, making it very handy for on the spot testing. Using genes from the biosynthetic pathway of this siderophore we aimed to control pyoverdine expression through the vanilate operon which could be cloned into Pseudomonas fluorescens.
Over the course of our project we were able to successfully clone the vanilate promoter into pSB1C3 and sequence verify that we achieved this. Successfully
cloning the promoter is the first step in using this operon to express the genes
for pyoverdine synthesis! We were also able to produce fluorescence values from pyoverdine when bound to aluminum and display the inhibitory affect Fe3+ ions
have on the aluminum pyoverdine binding capabilities. Our final step was
designing a model of our test to display how it would function in real world
We were interested in finding out just how big of a problem this issue of
toxic aluminum was in Nova Scotia. With previously collected data, we
were able to see not only how many rivers exceeded what's considered
'healthy' levels of ionic aluminum but also examine how ionic aluminum
concentration changes with differing pH and temperature.
Determining a ratio of pyoverdine fluorescence when metals are added
compared to the fluorescence of pyoverdine by itself allowed us to build
a model to predict the approximate aluminum and iron concentrations in
the water. This model showed that when iron is present in high concentrations
an iron chelator is needed to determine the amount of ionic aluminum present.
However, the model was successful when looking at the aluminum concentration
in areas that have a low concentration of iron.
Our Human Practices team was an integral part to our project’s success.
From the initial planning stages, our main goal behind our project
was to protect Nova Scotian coastal waters from toxic levels of
aluminium through our bacteria-based biosensor design. Thus,
our project was innately linked to environmental roots and the
conservation of current ecosystems. The Human Practices team
endeavoured on several science communication opportunities throughout
Nova Scotia, speaking to various populations affected by our project, from
the scientific community to general population. Promoting the environmental
ideals of our projects, the Team successfully engaged in meaningful
collaborations with other iGEM teams (where we were able to provide
our unique insight as the only Atlantic Canadian team!) and spoke with
experts in the field of biosensor development, public health and sustainability.
Outreach within our local community as well as educating the public on our
project was also important, as not only does excess levels of aluminum in
water have public health ramifications, but it was also important for our
team to explain how our bacteria biosensor design would contribute to
alleviating the problem while not causing other environmental concerns.
Our Human Practices team also utilized social media to communicate
science to the public, specifically via our Think of the PLOSibilities blog,
which removes scientific jargon found with research papers, thus making
science more accessible to ALL members of the public.