Particularity of environmental biotic factors impact on mammal’s organism

Abstract

This article explores ecological significance of animal venom as a stressful biotic factor and its role in disruption of homeostatic processes in mammal’s organism. The variety of venomous species of animals and their widely distribution in the world forces other species of animals to adapt to the coexistence with them. Thus, venom toxins have an important ecological significance, because they act as stressors and appreciably impact on the biotic interaction between organisms. According to scientists’ estimates, 220.000 species of animals, or 15% of the world’s biodiversity, are venomous, and there are 3.709 species of venomous snakes. The increase of snakebites cases is not only related to geographical distribution of snakes, but also to climate changes (high humidity and an increase of average annual temperature), which contributes to the reproduction of snakes and a shift of their natural habitats. Every year, around 5.4 million people are bitten by snakes worldwide. This leads to heavy social and economic costs in many countries of the world and it is the reason for constant attention to this problem. Among the variety of venomous animals, snakes have attracted the greatest attention of scientists due to peculiarities of the composition of their venom, its biochemical properties and the possibility of use in pharmacology and medicine. However, despite annual large-scale studies of the composition of snake toxins, the specifics of their effects on animals and human is not fully indentified. It has been established that among venomous snakes only vipers are common in Ukraine. Among them there are two subspecies of the common adder (Vipera berus Linnaeus, 1758): Vipera b. berus, which can be found in Polissia, Forest Steppe and the Carpathians, and Nikolsky’s viper (Vipera berus nikolskii Vedmederja, Grubant et Rudaeva, 1986), which occurs mainly in the Left Forest Steppe. Their bites can be very painful, but are rarely fatal for adults. Vipera berus venom has hemolytic, proteolytic and cytotoxic properties due to its composition: phospholipase A2, serine proteases, metallo proteases, amino acid L-oxidase, hemorrhagic factors and blood coagulation inhibitors, vasoactive peptides, cysteine-rich secretory protein. The composition of Vipera b. berus and Vipera b. nikolskii venom and mechanism of its action in victim’s organism were analyzed too. It is known that among the components of Nikolsky viper’s venom (Vipera b. nikolskii) the most part belongs to various enzymes. Of all enzymes, phospholipase A2 reached about 65% of the dry weight, serine proteases — 19%. Experiments on mammals (mice) showed that Nikol­sky’s viper (Vipera b. nikolskii) venom cause both local symptoms — swelling, pain, lymphangitis, and systemic symptoms — hypotension, mild neurotoxic effect. In addition, there are reports of damage to the cranial nerves and progressive paralysis of the limbs in mice. The components of Vipera b. berus viper venom have mainly a hemotoxic effect due to variety of enzymes from the metalloproteinase family, serine proteases, L-amino acid oxidases and C-type lectinlike proteins and cause enhanced blood coagulation. It is known that L-amino acid oxidases block the neuromuscular transmission of impulses and cause the destruction of cell membranes. The venom of this viper also contains several proteins that have a neurotoxic effect. A comprehensive and thorough analysis of experimental research data testify that the composition of toxins of various animal species, including vipers, is extremely diverse. Plenty of studies state about the hemovasotoxic and neurotoxic effects of these venoms. There are also reports of damage to the cardiovascular, urinary, respiratory, and digestive systems. It is noted that not all targets of viper toxins in mammal’s organism have been identified yet, and not all mechanisms of its action are understood, so further research is relevant.