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Navigating the world’s oceans by tapping into bacterial swimming strategies

Funding to understand how bacteria swim to stay alive could lead to the development of bacterial ‘biosensors’ to help the U.S. Navy navigate at sea.

The new study aims to explore whether tailoring the sensory machinery that allows bacteria to detect and respond to changes in their environment, could unleash their potential as bio-sensors.

Using bacteria to sense changes in ocean currents, depth and the salinity of seawater could lead to a self-sustaining source of sensitive and real time data that aids navy vessels, such as submarines.

Bacteria, such as Escherichia coli, have sophisticated cellular machinery, called the chemotactic network, that can quickly sense tiny changes in their environment.

Bacteria, such as Escherichia coli, swim by rotating tiny hair-like strands called flagella
Bacteria, such as Escherichia coli, swim by rotating tiny hair-like strands called flagella

Sensing environmental change

Bacteria can already detect minute changes in chemicals and nutrients. By sensing these changes bacteria can swim away from harm and maximise their chances of survival. 

Researchers from the University of Edinburgh will measure how bacteria respond to changes in salinity, which varies at sea depending on location, depth and time of year.

Bacteria may also respond to changes in water pressure and flow, so researchers will also explore if they could be used to detect changes in speed or ocean currents.

Environmental changes are picked up by specialised bacterial receptors that trigger the rotation of tiny hair-like strands, called flagella, on the surface of bacteria allowing them to swim.

Bacteria control the way they swim by altering the speed and direction of rotation of the ‘molecular motors’ that power the hair-like flagella.

Bacteria may aid real-time navigation if they are able to detect changes across a range of ocean conditions
Bacteria may aid real-time navigation if they are able to detect changes across a range of ocean conditions

Real-time navigation

Bacteria are already used as biosensors, for example, to detect toxins in water. But, the process is slow as it relies on the production of fluorescent proteins, which can take several minutes.

The sensitivity and speed of bacteria’s chemotactic network, which reacts in seconds, could make it ideal for real-time navigation if it is able to work across a range of ocean conditions.

Researchers will also need to investigate if bacteria can sense multiple signals at the same time and if there is potential to couple the chemotactic network to electrical outputs.

Understanding Swimming

The funding will not only aid understanding of bacteria’s potential as biosensors, but also lead to insights on why they swim and if it helps them to evade the body’s defences and cause infection. 

Previous studies have shown that some types of harmful bacteria use swimming to seek out target sites in the body where they can cause infection.

The study is funded by the Office for Naval Research and Defence Advanced Research Projects Agency.