RUDN University biologist found that Chinese date improves the immune system of fish
In fisheries, antibiotics are usually used to prevent infections. However, their use leads to the emergence of strains of bacteria resistant to them. This is a potential threat not only to fish but also to humans – in case that antibiotic-resistant bacteria begin to be transmitted from person to person. Researchers are looking for alternative drugs suitable for use in ichthyology.
Morteza Yousefi, a biologist from the RUDN University, and his colleagues investigated the properties of Zizyphus (Zizyphus jujube), known as "Chinese date" and found that it can be used as an antimicrobial agent for fish.
Morteza Yousefi tested the immunostimulatory properties of this plant on carp (Cyprinus carpio). The biologists gave the fish a solution of ethanol and distilled water with Ziziphus fruit juice with a concentration of 0.25%, 0.5%, and 1%. Then they took samples from the fish mucosa and monitored how immune parameters change: the number of antibodies, the activity of enzymes – proteases and the expression of genes of signaling molecules – cytokines, which, in particular, trigger phagocytosis, that is, the destruction of bacteria.
Analysis of the data showed that carp, which were given a solution of the fetus with a concentration of 0.5%, increased the number of antibodies. The more antibodies in the blood, the more extraneous compounds – antigens – they can "catch".
Besides, ichthyologists have found a connection between the extract of dates in the diet of fish and the presence of cytokines. The experiment showed that the concentration of the solution is 0.25% does not change the immune reactions of carp, but 0.5% and 1% solution increases the expression of cytokine genes and the activity of protease enzymes that are involved in the "digestion" of killed pathogenic bacteria and in triggering the processes of extraneous cells death (apoptosis).
The results are published in the journal Fish and Shellfish Immunology.
Scientists from the Winogradsky Institute of Microbiology RAS, RUDN University, St. Petersburg State University and the Tyumen Scientific Centre SB RAS studied the microbial communities from several lakes of the Yamal Peninsula. It turned out that methanotrophs (bacteria that use methane as a source of energy) consume methane more actively in the deep mature lakes of the peninsula than in small thermokarst lakes. In this regard, methane emissions into the atmosphere from the surface of deep lakes are low, and only small (relatively younger thermokarst lakes with constitutional ground ice) can make a significant contribution to methane emissions in the north of Western Siberia. Thus, bacteria perform an important function for the climate balance — they reduce the emission of methane into the atmosphere.
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