Most people have heard about fatty acids and how they are beneficial to humans. But not everyone knows what their usefulness is manifested in, and, moreover, few people have heard that in addition to omega-3 and omega-6 that have appeared in advertising, there are many other fatty acids that are important for scientific research.

On the eve of the International Day of Women and Girls in Science, we talked about the role of fatty acids in the life of not only people but also ecosystems with the winner of the L'Oreal, the UNESCO Award for Women in Science, and the SCOPUS Award Russia for the most cited Russian scientists in biology, Olesya Makhutova (Kormiletz), Doctor of Biological Sciences, Leading Researcher at the Institute of Biophysics of the Federal Research Center "KSC SB RAS".

How many fatty acids are there in living organisms?

- There are lots of them. In a sample, you can find more than a hundred fatty acids. I deal with large arrays of samples, and a variety of animals and plants pass through my hands. Although I am engaged in aquatic ecology, terrestrial objects also have to be processed since fatty acids are interesting as human food objects. As concerns the objects of my study, such as zooplankton or zoobenthos, we are talking about a hundred or more fatty acids.

- It turns out that the smaller the body, the more fatty acids it contains?

– The fatty acid composition of any organism is determined by two main factors. The first is its own synthesis of fatty acids, which depends on the body itself. There are organisms that synthesize a large set of fatty acids, so they are largely self-sufficient. For example, plants do not get organic compounds from food, they produce these compounds themselves. Animals in this regard are inferior to them.

The second factor is what the body has consumed. The more diverse the food of the organism, the more diverse will be its fatty acid composition. If the food, on the contrary, is very poor in terms of fatty acid composition, then there will be few of them in the body. So in pigs, poultry, cows, and animals that are fed under artificial conditions, the fatty acid composition of food is rather poor, and, accordingly, the fatty acid composition of the meat of these animals is not very large. An aquatic organism, consuming different groups of “objects”, receives different fatty acids and their composition can be very large.

What are fatty acids necessary for?

- Fatty acids from the viewpoint of the researcher and in terms of their importance can be divided into two groups. As to the first one, it concerns physiologically valuable fatty acids directly related to humans and practical applications. It includes only three polyunsaturated fatty acids: omega-6 - arachidonic and two fatty acids from the omega-3 family - docosahexaenoic (DHA) and eicosapentaenoic (EPA). From arachidonic and eicosapentaenoic fatty acids, very important substances are synthesized that are necessary for any multicellular organism - eicosanoids or hormone-like substances. Unlike hormones, these substances can be synthesized in any tissue, not just in a specific organ. Their impact on the body is very large, they regulate many important processes in the human body. Eicosanoids, which are synthesized from omega-6 acids, contribute to the body's reaction to irritants, for example, allergens, and provoke inflammatory processes: they cause an increase in sputum production, increase the temperature, increase the allergic reaction, constrict blood vessels, etc. Those fatty acids that are synthesized from the omega-3 act in the opposite way. They relax blood vessels, lower the temperature, and other pronounced reactions. It is great when there is a balance of these groups of fatty acids in the organism.

The third acid, docosahexaenoic one, is interesting in that it serves as a transmitter of the nerve impulse signal. Therefore, it is used in the construction of nerve cell membranes and it is necessary for the normal formation of the nervous system and good mental activity. There is a lot of it in the brain, in the nervous tissues, in the eye retina.

Where can we get these fatty acids?

“A part of our research work is focused on finding foods that are rich in omega-3 fatty acids in order to recommend people to consume these products to cope with the lack of omega-3.

Omega-3 fatty acids are not as common in terrestrial ecosystems as they are in aquatic ones. For humans, the main source of omega-3 fatty acids is fish. However, not all fish is rich in these acids. Rich in them are only those that get a lot of omega-3 fatty acids from food or synthesize them. We are conducting research which will allow us to tell which types of fish are able to synthesize important omega-3 fatty acids.
By the way, people consume omega-6 constantly, there is almost no deficiency in it. It is very abundant in meat, milk, and other meat products.

- What about the second group and the application of fatty acids of this group?

- The second direction is the value of fatty acids as markers. Let's go back to the beginning. Different taxonomic groups of organisms can synthesize their specific fatty acids. They can be used as markers. For example, we study the nutrition of an organism, and its fatty acid composition, and based on the fatty acid composition, we can say what the organism ate. This significantly expands our understanding of how complex food chains are in natural ecosystems.

At the end of last year, we wrote a chapter on how fatty acids can be used as markers in the international encyclopedia of aquatic ecosystems published by Elsevier. It is intended for those who are going to use this method in scientific research. The chapter is entirely devoted to the trophic direction of the application of fatty acids as markers. When we received an offer from the publisher to write this encyclopedia chapter, we gladly agreed. I have been working with trophic markers for about 15 years now, and have done a lot of work with various specialists on the subject of trophic relationships in aquatic ecosystems. This includes the research conducted with American colleagues on their ponds in Illinois, and on mollusks in the Rybinsk and Kanev reservoirs, the study of the nutritional spectra of organisms inhabiting the salty rivers of the Elton Lake basin, and now with colleagues from Moscow we are studying the nutritional spectra of semiaquatic invertebrates - springtails. I am actively developing this direction and I was glad that I could finally translate my work into a large review in the form of an encyclopedia chapter.

What are the prospects for your research?

– The study of food webs is a fundamental task. Its solution makes it possible to understand how organic matter is redistributed in the biosphere. The life of the ecosystem depends on the intensity of movement of various substances through food webs. If we remove one link, either the whole chain will break, or the system will be rebuilt, going along new paths. In this regard, it is important to all the mechanisms in the food chain. Concerning large land animals, our knowledge is more extensive due to the fact that they are easier to observe. Aquatic ecosystems are more of a mystery to us, and it is much more difficult to study them.

It is important to study the entire aquatic ecosystem. In our laboratory, under the supevision of RAS Corresponding Member Mikhail Ivanovich Gladyshev, specialists from various fields were brought together: taxonomists, classical hydrobiologists with the knowledge about phytoplankton, zooplankton, zoobenthos, ichthyologists, biochemists and hydrochemists, and geneticists. We also cooperate with hydrophysicists, specialists in the field of mathematical modeling. Together, we can study the functioning of the aquatic ecosystem, taking into account all aspects. This is a big advantage.

Moreover, the aquatic ecosystem must be studied together with the terrestrial one. After all, they are very closely related. Many insects, such as caddisflies, mayflies, and stoneflies, are only in the larval stage in the water. And then they fly out of the reservoir and carry the substances that they received in the water onto the ground. A few years ago, a new direction for us to study the contribution of aquatic organisms to terrestrial ecosystems appeared in our laboratory. This year, together with colleagues from Vladivostok, we have decided to focus on the reverse flow of substances - from land to water since organic matter also enters aquatic ecosystems from terrestrial ones. For example, in autumn a lot of leaves and other litter fall into the reservoir. What happens to it, do aquatic organisms feed on this organic matter, or is it buried there? What contribution to the flow of substances is made by terrestrial insects that fall on the water surface and are eaten by fish? We actively go beyond the boundaries of aquatic ecology, we already have entomologists in our research team. So to say, this is a real evolution from water to land. As it is with life, so is it with scientific research.