In most cases, the light produced by bioluminescent beings is blue, for example, that of marines is in the wavelength of 550 nanometers (nm) and in fireflies, between 510 and 660 nm. And the basis is always the same, whether in the case of bacteria such as Vibrio fischeri; in dinoflagellates that are part of the phytoplankton, such as the species Noctiluca scintillans; in fireflies, which are terrestrial, or also in deep ocean shrimp, Acanthephyra purpurea. It is a chemical reaction produced by these beings. To achieve this, they have a molecule called luciferin that, in the presence of oxygen and using the ATP in the cells, which is what provides energy to any cellular reaction, and through the action of an enzyme called luciferase, oxidation of the molecule. The luciferin is excited by oxidation and when it returns to its normal energy level it emits that light.
That is, the molecule is luciferin, the enzyme (molecule that facilitates chemical reactions in cells) is luciferase and uses oxygen that is in cells and ATP. This luciferin oxidation reaction is activated for various reasons. It may be in response to stress. For example, in the case of phytoplankton it is due to agitation. When we see light in the waves it is due to the agitation caused by the movements of the water that induce this reaction in the phytoplankton. In the case of animals, it can be in response to an attack, as a defense to scare away that predator. And in the case of fireflies it is to attract their mates. In other words, the biological function of bioluminescence is varied, but the chemical reaction that produces it is always the same.
In the case of fireflies, for example, the light is produced by themselves. In the case of deep-sea fish, it is due to a symbiosis between these fish and some types of bioluminescent bacteria. The reaction does not occur in the fish itself, but instead has a kind of vesicle in which bioluminescent bacteria accumulate and the fish take advantage of the light emission of these bacteria for their own purposes. In most cases to attract prey. They open their mouths, in a very dark environment such as the abyssal, and that light attracts other smaller fish that serve as food.
As I explained to you, these beings use bioluminescence for biological purposes. They turn on or off when they need it, in response to a stimulus that is different depending on the species in question. They are not emitting light all the time, only when the stimulus arrives that in each case provokes the luciferin reaction. And this is so because producing light involves a large energy expenditure, since they consume ATP. That is why they are not “on” all day. They must use it in a metabolically profitable way.
Some of these species are used commercially for their bioluminescence. For example, the bacterium Vibrio fischeri which is a marine bacterium, varies its level of light emission in the presence of pollutants. And that characteristic has been used to put up for sale biotechnological tests that use this bacterium to measure the presence of hydrocarbons in water or glyphosate, which is a herbicide, in the terrestrial environment.
Ana Bartual Magro She is a full professor at the Faculty of Marine and Environmental Sciences of the University of Cádiz and a researcher registered with INMAR (University Institute of Marine Research).
Question sent via email by Christian Ledezma
Coordination and drafting:victory bull
we answeris a weekly scientific consultation, sponsored by theDr. Antoni Esteve Foundationand the programL’Oréal-Unesco ‘For Women in Science’, which answers readers’ questions about science and technology. They are scientists and technologists, partners ofAMIT (Association of Women Researchers and Technologists), which answer those questions. Send your questions to[email protected]or on Twitter #nosotrasrespondemos.
You can follow MATTER on Facebook, Twitter and Instagramor sign up here to receive our weekly newsletter.
#bioluminescent #beings #produce #light