How do bioluminescent organisms produce light? | Scientists respond | to know

In most cases, the light produced by bioluminescent organisms is blue, for example, the light from marines has a wavelength of 550 nanometers (nm) and in fireflies, between 510 and 660 nanometers. And the basis is always the same, whether in the case of bacteria such as Vibrio Fishery; In dinoflagellates that are part of phytoplankton, such as species Noctiluca scintillans; In wild fireflies, or also in deep-ocean shrimp, Acanthevira purpurea. It is a chemical reaction produced by these organisms. To achieve this, they have a molecule called luciferin, in the presence of oxygen and using ATP in cells, which provides energy for any cellular reaction, and through the action of an enzyme called luciferase, oxidation of the molecule. Luciferin is affected by oxidation and when it returns to its normal energy level it emits this light.

This means that the molecule is luciferin, and the enzyme (the molecule that facilitates chemical reactions in cells) is luciferase and it uses the oxygen in the cells and ATP. The luciferin oxidation reaction is activated for various reasons. This may be a response to stress. For example, in the case of phytoplankton it is due to agitation. When we see light in waves, it is due to the agitation caused by the movements of the water that stimulates this reaction in phytoplankton. In the case of animals, it can be a response to an attack, as a defense to scare off this predator. In the case of fireflies, they attract their companions. In other words, the biological function of bioluminescence varies, but the chemical reaction that produces it is always the same.

In the case of fireflies, for example, light is produced on its own. In the case of deep-sea fish, this is due to the symbiosis between these fish and some species of bioluminescent bacteria. The reaction does not occur in the fish themselves, but instead there is a type of vesicle in which the bioluminescent bacteria accumulate and the fish take advantage of the light emission from these bacteria for their own purposes. In most cases to attract prey. They open their mouths, in a very dark environment like abyssal, and this light attracts other smaller fish that serve as food.

As I explained to you, these organisms use bioluminescence for biological purposes. They turn on or off when they need it, in response to a stimulus that varies depending on the species involved. They do not emit light all the time, only when the stimulus arrives which in each case provokes a luciferin reaction. This is because the production of light involves a significant expenditure of energy, since it takes up ATP. That is why they do not “work” all day. They must use it in a way that is metabolically profitable.

Some of these species are used commercially for bioluminescence. For example, bacteria Vibrio Fishery They are marine bacteria, and their level of light emission varies in the presence of pollutants. That property has been used to sell biotech tests that use these bacteria to measure the presence of hydrocarbons in water or glyphosate, a herbicide, in the terrestrial environment.

Anna Bartoal Magrau She is a full professor at the Faculty of Marine and Environmental Sciences of the University of Cadiz and a registered researcher with INMAR (University Institute for Marine Research).

The question was sent by e-mail Christian Ledesma

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