Shine bright like a dinoflagellate

By Anna Tiley

We are constantly surrounded by bright artificial light emitted from our phones, computers, cars and light bulbs. Yet what if we could read by the light of a bacteria-powered bulb? Or walk down a street lit entirely by glowing trees? These may seem like surreal concepts but they are examples of projects aimed at harnessing the fascinating power of bioluminescence.

Organisms are able to produce bioluminescence due to a chemical reaction in their cells which makes them emit light. In nature there are many examples of different bioluminescent organisms ranging from fish to plants, insects, bacteria and even fungi. In fact, it has been estimated that this process has evolved independently on around 50 different occasions.

Bioluminescence has evolved for a variety of different reasons. It can be used by prey to startle, distract or warn predators. Likewise, emitting light can also be beneficial to predators as a way to find, stun or attract prey.

Despite having evolved on many separate occasions, the basic process by which bioluminescence occurs remains the same. All forms of bioluminescence result from a chemical reaction involving an enzyme, usually luciferase, which causes a molecule called luciferin to react with oxygen. The action of the luciferase enzyme causes the luciferin to emit light, thus making the organism glow.

Waitomo Glow Worm Caves #NewZealand by 2il org

Waitomo Glow Worm Caves #NewZealand by 2il org

However, it isn’t always beneficial to emit light, so some organisms have adapted methods to control their bioluminescence. For example, some unicellular algae called dinoflagellates only glow when they encounter mechanical stress such as a predator.

Normally the algae supress their bioluminescence by making a protein that binds to the luciferin molecule, making it inaccessible to the luciferase enzyme. When the algae encounter the stress, the cell becomes slightly acidic. This makes the protein release the luciferin, enabling the enzyme to bind to it and the organism to glow.

Bioluminescence has fascinated people for centuries and more recently we have been able to use it in scientific research. In the lab, the luciferase gene has been used as a way to investigate gene expression patterns, interactions between proteins and to track disease progression. The advantage of using luciferase is that it isn’t invasive and observations can be made in real time.

Some start-up projects also aim to harness bioluminescence in novel ways. Examples include bacteria-powered bio bulbs, glowing trees and plants which can be used as an alternative source of light in the home. Although these may not be as efficient as electrical lights and may take a while to become widely available, the concepts are certainly exciting!