Репозиторий Университета

© 2018 GEOTAR-Media Publishing Group. Yessotoxin and its derivatives (about 90) are isolated from algae belonging to the species Protoceratium reticulatum, Gonyaulax cf. Spinifera, Lingulodinium polyedrum and from invertebrate organisms that feed on these algae. Previously yessotoxin have been associated with the group of diarrheal toxins. Later studies of the possible impact of yessotoxin on the activity of alkaline phosphatase allowed to exclude them from this group. Yessotoxin causes a violation of calcium entry in the cells, which, in turn, effects the calcium-calmodulin system and thus influences into homeostasis of the organism as a whole. It was shown that yessotoxin induces a biphasic change in the concentration of adenosine monophosphate, an initial increase with a subsequent relative decrease, within some minutes after adding the toxin to the lymphocytes cell culture. Yessotoxin has effects on immune system; which is manifested in an increase of cytokines level, by inducing the expression of the genes encoding them. Yessotoxin have impact into processes of cell adhesion via E-cadherin and, thus, could be an important factor in the development of Alzheimer's disease. It has been established that yessotoxin caused the development of apoptosis. In those cases all three mechanisms of cell death took place - apoptosis, paraptosis and autophagy. Yessotoxin's acute toxicity doses according to different data are from 100 to 500-750 μg per 1kg of body weight. Yessotoxin's acute reference dose (ARfD) - 25 μg/kg of body weight per day. The results of the analysis of yessotoxin level in shellfish meat showed that none of the studied samples contained more than 3.75 mg yessotoxin equivalents/kg shellfish meat. This level has been adopted by the European Union as the maximum acceptable level of yessotoxin in shellfish meat (EU Regulation N 786/2013). Presented data on the mechanism of action, toxicity and prevalence of yessotoxins make it necessary to establish regulations of their content in seafood, placed on the markets of the Eurasian Economic Union.

© 2018 Ruslania. All rights reserved. This literature review is devoted to modem notions about molecular mechanism of action of the selective modulators of progesterone receptors. The superfamily of nuclear receptors represents ligand-activated transcription factors and includes receptors for steroid hormones, lipophilic vitamins, sterols, and bile acids. These receptors serve as targets for creating numerous drugs. As a result, a new class of compounds (ligands) appeared exhibiting agonistic/partial agonistic/antagonistic functional activities depending on the context (tissue or gene target). This class of ligands is called selective modulators of nuclear receptors. Initially, mifepristone was developed as the progesterone receptor antagonist, but further it demonstrated the properties of a selective modulator of progesterone receptor and became the ancestor of this group. At present, the development of new selective modulators of progesterone receptor is aimed at obtaining higher selectivity with respect to progesterone receptors and decreasing the anti-androgenic and anti-glucocorticoid properties. Unfortunately, most of the subsequent selective modulators of progesterone receptors exhibited hepatotoxicity, which limited their wide introduction into clinical practice.