Spiders are the most important entomophagous animals in ecosystems. They are also the most numerous poisonous animals on the planet, and they are indispensable regulators of populations, killing mainly insects and other small arthropods. Spiders are an integral part of the food chain; they produce venom serving to immobilize the prey. Spider venoms are a “natural combinatorial library” of biologically active substances, with varying effectiveness and specificity. A feature of the biological effect of the spider’s venom is a unique combination of the low toxicity of the whole venom, for both animals and humans, with high selectivity of the interaction of the neurotoxins, which are part of the venom, with the molecular structures of ion channels and synaptic receptors of the nervous system. The present review introduces new fundamental facts, ideas, and perspectives of the practical application of spider venoms in biomedical research and drug design. The current state of research on a unique set of polypeptide toxins, serving as chemical factors (allomons) of the interspecific (allelochemical) interactions of spiders of the family Thetaphosidae, is considered. Up-to-date information on the structure of spider venom toxins is analyzed using the UniProt database. The latest bioecological and toxicological characteristics of tarantulas are presented. The chemical nature and mechanism of action of some unique toxins selectively acting on key processes in the nervous system are considered. The toxins act upon synaptic transmission and the functioning ion channels, which allow spiders both to interact with various molecular targets of the prey or predator and to implement various life strategies, gaining an evolutionary advantage.

The direction of adaptive reactions of healthy and Hepatozoon spp.-infected green frogs from water bodies of Nizhny Novgorod oblast with various hydrochemical conditions was studied. During the observation period, infection of pool frogs and an increase in the total population indicators of infection of male and female marsh frogs with Hepatozoon spp. were revealed. Hypertrophy of the morphometric parameters of infected blood erythrocytes compared with healthy cells was revealed in marsh frogs. The content of neutrophil granulocytes in the blood of infected marsh frogs was higher compared to healthy individuals, while the level of immune complexes did not differ. In infected pool frogs, an increase in the level of large immune complexes in the blood serum and the enlargement index was revealed compared to healthy ones against the background of a general decrease in the body’s resistance in conditions of severe pollution of their habitat with heavy metals and sulfates. For marsh frogs, a correlation was established between the proportion of infected erythrocytes and the content of myelocytes and young forms of neutrophils in the blood; while for pool frogs, there was a correlation with the content of neutrophils and the enlargement index of immune complexes. The method of multivariate analysis of variance revealed a significant influence of factors such as sex and the interaction of sex/infection with hemoparasites on the immune status of amphibians.

—The aim of this work was to estimate the state of the populations of tailless amphibians in the anthropogenic territory according to a complex of indices of immune homeostasis of the organism. The marsh frog Pelophylax ridibundus (Pallas, 1771) and the pool frog P. lessonae (Camerano, 1882) from natural populations of water objects from the city of Nizhny Novgorod were used in the work. The priority chemical pollutants of the reservoirs were determined using a spectrophotometry method. The species identification was performed using a multiplex PCR test system. The results of identification were verified by sequencing of the mitochondrial ND2 gene and a fragment of the nuclear SAI gene. The number of erythrocytes, leukocytes, leukocyte profile, and the level of immune complexes were determined in all individuals collected. Exceeding the water quality standard by the content of heavy metals was determined for fishery reservoirs in all water objects. Molecular genetic diagnostics demonstrated the presence of both “pure” P. ridibundus and individuals with introgressive mtDNA of the Anatolian form of the marsh frog ( P. cf. bedriagae ) in the sample of marsh frogs. In the sample of pool frogs, all individuals studied had only species-specific markers of mt- and nDNA markers of P. lessonae. The marsh frogs differed from the pool frogs by an increased content of erythrocytes, neutrophils, basophils, and small immune complexes and a decreased content of lymphocytes. The detected changes in the immunohematological indices of green frogs were caused by the complex genotoxic effect of the pollutants of water objects. A decrease in the lymphocyte/eosinophil ratio index with an increase in the concentration of nitrites, an increase in the activity of humoral immune responses under conditions of the pollution of water environment with sulfates, an increase in the portion of immature leukocyte cells (myelocytes) in the blood of the frogs with an increase in the concentration of manganese and nitrates in the water were demonstrated. Under conditions of environmental stress (determined by the level of water pollution), the regulatory systems of the frog blood reflected a stress-induced response, which was more pronounced in the organism of marsh frogs as compared to the pool frogs.

In order to check the health of individuals of the Mediterranean tortoise Nikolskii Testudo graeca nikolskii Ckhikvadze et Tuniyev, 1986 (22 individuals: 6 males and 16 females) collected in the vicinity of Anapa (Krasnodar region of Russia), a haematological approach was used to assess adaptive blood reactions. Intraerythrocytic parasites Haemogregarina spp. (Adeleorina, Coccidia) were detected in blood smears of 54.5% of turtles. Female were more prone to infection with hemogrega-rines than males, as evidenced by higher invasion index, mean invasion intensity and proportion of infected cells. Individual stages of hemoparasite development (gametocytes and trophozoites) were found in blood erythrocytes with equal frequency. No differences were found in the leukocyte composition of the blood between infected and healthy female and male. Lymphocytes predominated in the leukogram of turtles. The dependence of the increase in the number of eosinophils in the peripheral blood of turtles on the content of trophozoites in erythrocytes was revealed. Parasitic forms of Haemogregarina spp. affected the host's immune response and it is necessary to identify possible harmful long-term consequences of infection for T. g. nikolskii Ckhikvadze et Tuniyev, 1986 from Krasnodar region.

A comparative interspecific assessment of the leukocyte profile of young Elaphe dione, Natrix natrix and N. tessellata is given. Juvenile snakes were obtained in captivity from females captured, being pregnant, from Volga populations. Eosinophils and basophils predominated in the blood of young E. dione, the total content of mononuclear cells (agranulocytes) was lower compared to the young of N. tessellata and N. natrix. At the same time, the species of the genus Natrix differed in the content of all three types of mononuclear cells, namely: the proportion of azurophils and monocytes was higher in N. tessellata, and that of lymphocytes was higher in N. natrix. The main contribution to the balance of mononuclear cells was made by lymphocytes. The leukocyte composition of young snakes had no pronounced lymphocytic profile, the contribution of the specific reactivity of the organism to the overall adaptive response of the body of young snakes to environmental conditions was small. According to the content of lymphocytes, the studied species were arranged in descending order in the following row: N. natrix (Me – 60.00, IQR – 2.50) → N. tessellata (52.00, 6.00) → E. dione (40.00, 5.00). The increased value of the leukocyte shift index in E. dione young testified to the predominant role of granulocytes in the immune response with some lag of lymphocyte-monocyte cells and later activation of the effector link of the immune response (lymphocytes) compared with young of N. natrix and N. tessellata. While the specific reaction of the immune system decreased, a compensator activation of the nonspecific protective blood system was observed in the organism of E. dione. The increase in the content of granulocytes in the blood of young snakes was a characteristic indicator of an increase in environmental stress, assessed by the integral leukocyte index (the ratio of heterophiles and lymphocytes). Integral leukocyte indices reflected an imbalance of the adaptive response of the blood system in young snakes kept in captivity in relation to adult males and females from natural populations.

The results of our comparative analysis of parameters of the leukocyte blood system of underyearlings and mature specimens of the common viper Vipera berus are presented. The material was the blood of 36 females and 26 males caught in the Middle Volga basin, and 13 underyearlings born in captivity from 4 females of this sample. V. b. berus underyearlings differed: from the females by a lower content of heterophils and azurophils, an increased content of eosinophils and basophils, an increase in the leukocyte shift index, a decrease in the lymphocytic–granulocytic index, the index of the of heterophil–eosinophil ratio, the index of the lymphocyte–eosinophil ratio; from the males by a reduced content of heterophils, an increased content of eosinophils and basophils, an increase in the leukocyte shift index, the index of the heterophil–eosinophil ratio, and the index of the lymphocyte–eosinophil ratio. In general, the adaptive response of the blood system of underyearlings indicated the later activation of lymphocytes as an effector link and the imbalance of the immune response due to the lack of a resource of immunocompetent cells (agranulocytes) compared with the indices of adults from natural populations.

A comparative analysis of the leukocyte composition of the blood of Emys orbicularis and Trachemys scripta from the Samara Zoo was carried out. Statistically significant interspecies sex differences in the content of granulocytes (heterophiles, basophils and eosinophils) in the blood were established. The proportion of agranulocytes in the blood of both species was the same. Multivariate analysis of variance revealed a significant effect of species, sex, and their interaction on the leukocyte composition of the blood of turtles. At the same time, males of E. orbicularis differed from males of T. scripta by an increased content of heterophiles in the blood, and females differed from females by an increased content of heterophiles and a decreased content of basophils. An analysis of leukocyte indices revealed a more active component of the nonspecific natural resistance of the organism of E. orbicularis females compared to males and females of T. scripta. In captivity, E. orbicularis experienced greater stress relative to T. scripta, as evidenced by an increased value of the index of the ratio of heterophils and lymphocytes and a lower content of eosinophils. With an increase in body size, an increase in the relative content of lymphocytes in the blood of T. scripta females and an increase in stress resistance were noted, while in E. orbicularis such a specific immune reaction was not observed. We believe that the species-specific adaptive reaction of the blood system gives competitive advantages to the spreading exotic species T. scripta, which potentially threatens natural populations of E. orbicularis.

A comparative analysis of leukograms and morphometric features of blood cells of three species of tortoises from the Samara Zoo was carried out: Testudo horsfi eldii Gray, 1844; Geochelone elegans (Schoepff, 1795); Chelonoidis carbonarius (Spix, 1824). Interspecies statistically signifi cant differences in the total content of agranulocytes and granulocytes were revealed. The leukocyte profi le indicated a pronounced innate immune response in tortoises and a more active cell-mediated adaptive response in C. carbonarius. According to the totality of integral indicators of the leukocyte profi le, the most stable and balanced immune response was noted in T. horsfi eldii. The variability of karyocytometric parameters of turtle blood cells was revealed. The share of variability in the area of cell nuclei, depending on the area of the cell itself, was the highest for different cells in different species: T. horsfi eldii (basophils), G. elegans (platelets), C. carbonarius (eosinophils). The area of blood cells (with the exception of eosinophils) and the nuclearcytoplasmic ratios of cells of the same type in different turtle species varied. A higher metabolic activity of blood cells of T. horsfi eldii was established in comparison with G. elegans and C. carbonarius.

The length of the body without a tail (L.) and the length of an intact tail (L. cd.) were measured in 91 males and 110 females of Anguis colchica from the Chamzinsky rayon of the Republic of Mordovia. A comparative analysis of three morphometric characters (L., L. cd., L. / L. cd.) of males and females was carried out with the construction of variation series and using the frequency approach. Range of variability of L. and L. cd. (from 120 to 279 mm) were divided into eight classes, of which, according to body length without the tail, males were represented in seven, females in eight classes; According to the length of the tail, males were represented in six, and females in eight classes. Tail length depended on body length in males (r = 0.903, p < 0.001, R2 = 0.81) and females (r = 0.925, p < 0.001, R2 = 0.857). The proportions of males and females with a body length of 159 mm and less in the sample did not differ (p = 0.337), in the average size classes (from 160 to 199 mm) males predominated (p = 0.05), in size classes greater than 220 mm – females (p = 0.021). In the size class 200–219 mm, long-tailed females predominated.

A comprehensive atomic-emission study and comparative assessment were done of the content and distribution of heavy metals (Mn, Cu, Cr, Al, Fe, Zn, and Sr) in the organs and tissues (muscles, skin, bones, gonads, liver, heart, spleen, and blood) of marsh and pool frogs collected in the lakes of a big industrial city (Nizhni Novgorod). High concentrations of heavy metals were found in the spleen (Cr), bones (Zn and Sr), liver (Cu) of lake frogs. High coefficients of the biological absorption of Mn, Sr, Zn (bone tissue), Fe (liver, spleen), and Cu (heart) were found in pool frogs. The cumulative properties of heavy metals were estimated from the accumulation coefficient established. Species regularities of heavy metal accumulation from water are presented in descending order as the following series: Zn > Cr > Al > Cu > Fe > Sr > Mn for pool frogs; and Fe > Zn > Mn > Cu > Cr > Al > Sr for marsh frogs. The priority intake of chromium, manganese, aluminum and strontium from the aqueous medium into the body occurred through the skin. Active zinc accumulation occurred mainly through food, which was confirmed by high values of the biological absorption coefficient of zinc for the liver of Pelophylax ridibundus and Pelophylax lessonae. The dependence of the heavy metal accumulation in the muscles from the organs in contact with the external environment (skin) and the digestive system (liver) was established by regression analysis. The most important adaptation of tailless amphibians is their ability to prevent excessive accumulation of heavy metals in their body, while living in the conditions of increased environmental pollution. Our results obtained speak for the high accumulation of heavy metals in the body of tailless amphibians, determined by the conditions of the aquatic environment and the bioavailability of these metals.

Data on the leukocyte blood composition of two co-habiting species of freshwater turtles, Emys orbicularis and Mauremys caspica, from the Republic of Dagestan (Russia) are provided. Lymphocytes are the predominant cells in the blood of females and males of both species. Heterophils predominated among granulocytes. Two-way multivariate analysis of variance showed a statistical significance of the influence of two factors on the leukocyte formula of freshwater turtles, namely: species (λWilks = 0.459, p < 0.001), sex (λWilks = 0.809, p = 0.019) and their interaction (λWilks < 0.001, p < 0.001). The blood formula (WBC) of E. orbicularis females showed higher levels of eosinophils (z = 3.040, p = 0.001) and basophils (z = 5.394, p < 0.001) and reduced levels of heterophils (z = 3.579, p < 0.001) and lymphocytes (z = 3.391, p < 0.001) compared to M. caspica females. Males of E. orbicularis differed from those of M. caspica by increased levels of eosinophils (z = 2.716, p = 0.003) and basophils (z = 4.829, p < 0.001) and a reduced level of heterophils (z = 3.474, p < 0.001). With general adaptive responses, interspecific differences were clearly expressed: the variability in the parameters of the white blood cell system of E. orbicularis was associated with rearrangement of the ratio of granulocyte cells (heterophils, eosinophils and basophils). The predominance of a specific component of the immune system (lymphocytes) was found in the immune responses of M. caspica. Changes in the leukocyte profiles of freshwater turtles were associated with a change in the agranulocyte–granulocyte ratio, which was confirmed by statistically significant differences in the integral leukocyte indices. The leukocyte profile of Emys orbicularis testified to the insufficient resource of adaptive mechanisms in specific environmental conditions. On the other hand, the blood formula (WBC) showed the possibility of an active response, more pronounced in M. caspica than in E. orbicularis.

Abstract—Data on the leukocyte blood composition of two cohabiting species of freshwater turtles, Emys orbicularis and Mauremys caspica, from the Republic of Dagestan (Russia). Lymphocytes are the predominant cells in the blood of females and males of both species. Heterophils predominated among granulocytes. Two-way multivariate analysis of variance showed a statistical significance of the influence of two factors on the leukocyte formula of freshwater turtles, namely, species (λ Wilks = 0.459, p < 0.001), sex (λ Wilks = 0.809, p = 0.019), and their interaction (λ Wilks < 0.000001, p < 0.001). The blood formula (WBC) of E. orbicularis females showed higher levels of eosinophils (z = 3.040, p = 0.001) and basophils (z = 5.394, p < 0.001) and reduced levels of heterophils (z = 3.579, p < 0.001) and lymphocytes (z = 3.391, p < 0.001) compared to M. caspica females. Males of E. orbicularis differed from those of M. caspica by increased levels of eosinophils (z = 2.716, p = 0.003) and basophils (z = 4.829, p < 0.001) and a reduced level of heterophils (z = 3.474, p < 0.001). With general adaptive responses, interspecific differences were clearly expressed: the variability in the parameters of the white blood cell system of E. orbicularis was associated with rearrangement of the ratio of granulocyte cells (heterophils, eosinophils, and basophils). The predominance of a specific component of the immune system (lymphocytes) was found in the immune responses of M. caspica. Changes in the leukocyte profiles of freshwater turtles were associated with a change in the agranulocyte–granulocyte ratio, which was confirmed by statistically significant differences in the integral leukocyte indices. The leukocyte profile of Emys orbicularis testified to the insufficient resource of adaptive mechanisms under specific environmental conditions. On the other hand, the blood formula (WBC) and body reactivity indices of the two species showed the possibility of an active response, which was more pronounced in M. caspica than in E. orbicularis.

A comparative estimation of the leukocyte profile of the marsh turtle Emys orbicularis (Linnaeus, 1758) living in the Ural river basin (Orenburg region, Belyaevsky district, 11 females and 5 males) and in the Volga river basin (Astrakhan region, Krasnoyarsk district, 28 females and 20 males) was made. The blood formula (WBC) of males and females was calculated together with the calculation of integral leukocytal indices (the lymphocyte-granulocyte index, the leukocyte shift index, the heterophile/lymphocyte ratio, the heterophil/eosinophil ratio, and the lymphocyte/eosinophil ratio). Lymphocytes were the predominant leukocyte cells in the peripheral blood of Emys orbicularis (40–45%). Among granulocytes, heterophiles (the population from the Orenburg region) or basophils (the population from the Astrakhan region) predominated. The absence of any differences in the quantitative indicators of the blood formula and integral indices for males and females indicated a comparable level of impact and identity of the physiological adaptation mechanisms occurring in the animals in the Orenburg region. Intersexual differences were manifested in an increased content of monocytes (u = 3.13, p = 0.001), which indicated activation of the natural immunity of males in comparison with females from the Astrakhan region. The leukocyte composition of the Emys orbicularis blood differed in the content of granulocytes and agranulocytes in different populations. The males from the Orenburg region differed from those from the Astrakhan region by an increased proportion of heterophiles and a reduced content of basophils. Females differed in all blood count parameters, except for eosinophils whose fraction was equal (u = 0.71, p = 1.00). In the peripheral blood of females from the Orenburg region, a higher content of heterophiles, monocytes and a lower content of basophils and lymphocytes were found in comparison with those from the Astrakhan region. Quantitative-qualitative changes were detected in the leukocyte composition of the blood during the invasion of hemoparasites. The specific immune response (the content of lymphocytes) decreased, and the nonspecific defense system (the content of heterophiles) increased. The maintenance of the immunological reactivity of the organism under the conditions of invasion was determined by the functional activity of heterophiles, which was confirmed by a higher value of the heterophil/lymphocyte index. The blood formula (WBC) and the dynamics of leukocytal indexes of Emys orbicularis reflected the active response of the organism to a complex of environmental factors, including parasitic invasions.

Samples of marsh frogs (Pelophylax ridibundus) were collected from two thermal reservoirs in the southeastern part of the Kamchatka Peninsula: (1) from a discharge channel of Thermal Power Plant no. 2, Petropavlovsk-Kamchatsky (hereinafter TPP); and (2) from thermal waste waters of the Township of Paratunka (hereinafter Paratunka). The concentrations of iron and manganese in the TPP waters are higher than in Paratunka by 7 and 1.2 times, respectively; while the concentrations of cobalt, copper, and nickel in the TPP waters are lower in comparison with Paratunka. The striata and hemimaculata phenetic morphs predominate in the Paratunka population; while maculated (maculata), white-throated (albicollis), and white-bellied (albiventris) individuals predominate in the TPP population. Both males and females in the TPP population feature higher average age, body length, body weight, and postmetamorphic growth rate values in comparison with the Paratunka population. Males in the TPP population feature a significantly higher relative testes mass, which can be a compensatory reaction to the complex of pollutants. For the first time, the predominance of erythrocytes with attached micronuclei was identified in marsh frog populations of Kamchatka, which indicates chromosomal aberrations induced by mutagens present in the aquatic environment. Sexual differences in the proportion of erythrocytes with attached micronuclei have been identified in frogs of the Paratunka population, which indicates a higher mutation frequency in erythrocytes of males in comparison with females. The proportion of micronuclei increases in erythrocytes of older individuals; apparently, this is due to the cumulative effect of xenobiotics present in the aquatic environment. The morphophysiological indices (i.e., relative masses) of organs make the highest relative contribution to the total variance of the set of characteristics studied in marsh frogs belonging to two different populations; while cytogenetic disordersin somatic cells identified by the micronucleus test make the greatest difference in sexual differences (Paratunka population only).

The state of the grass snake (Natrix natrix) population in the Mordovian State Nature Reserve was assessed using the hematological approach. The leukocyte blood count was estimated together with calculation of the associated leukocyte indices (neutrophil:lymphocyte (N:L), eosinophil:lymphocyte (E:L), heterophil:eosinophil (H/E) and heterophil:lymphocyte (H:L) ratios). The surface area of leukocytes (heterophils, basophils, eosinophils, azurophils, monocytes, and lymphocytes) was measured. The leukocyte blood composition of Natrix natrix was characterized by the predominance of agranulocytes, and the granulocyte fraction was 31– 37% (u = 1.99, p = 0.04). The population pattern of the leukocyte blood composition of Natrix natrix was as follows: heterophils – 8.07±0.6%, basophils – 12.33±0.95%, eosinophils – 8.33±0.65%, azurophils – 5.25±0.53%, monocytes – 9.77±0.42%, and lymphocytes – 56.22±1.7%. According to the averaged area, the leukocytes were arranged in the following order: eosinophils – monocytes – azurophils, basophils – heterophils – lymphocytes. The diameter of the largest cells (eosinophils) was (17.5±2.42) μm. The smallest lymphocytes had diameters within (7.22±1.21) μm. The absence of any differences in the quantitative content of all types of granulocytes and agranulocytes in the blood of the grass snake from different parts of the reserve indicated a comparable level of impact and the identity of the physiological mechanisms of adaptation that occur in the body of animals in protected habitat conditions. Most of the leukocyte integral indices revealed the same type of variability in the parameters of the white blood cell system of the Natrix natrix in three areas of the reserve, with the exception of an increased value of the heterophiles/lymphocytes ratio in the sample from the village Pushta. The increase in this indicator made it possible to draw a conclusion about the stress effect on the individuals of this sample. The principal component method was used to differentiate the samples of the grass snake with a more complete quantitative description of the leukocyte composition of the objects of study; the results obtained are presented in a visual, integrated and generalized form. The use of the principal component method made it possible to combine samples of Natrix natrix with similar indicators of leukocyte composition, as well as to identify a population of Natrix natrix that differs in its indicators in the urbanized territory of the Samara region. The blood pattern and the dynamics of blood leukocyte indices reflected the active response of the Natrix natrix body to the complex of environmental factors of the habitat on the territory of the Mordovian State Nature Reserve.

Two populations of marsh frogs, Pelophylax ridibundus, were sampled in habitats with thermal waters in the southeastern part of the Kamchatka Peninsula, Russia: in a discharge canal of the thermal power plant of Petropavlovsk-Kamchatski (TPP) and in waste thermal waters of the settlement of Paratunka (Paratunka). In TPP waters, the concentrations of iron (7 x) and manganese (1.2 x) were higher than in Paratunka waters, vs. the concentrations of cobalt, copper and nickel which were lower. The phenetic morphs "striata" and "hemimaculata" prevailed in the Paratunka population, while the maculated ("maculata"), white-throated ("albicollis") and white-bellied ("albiventris") frogs dominated the TPP ones. The average values of age, body length and body weight, as well as the postmetamorphic growth rate for both sexes were higher in TPP compared to the Paratunka population. As the relative testes mass was also significantly higher in the TPP population, this could be considered as a response to pollutants. The prevalence of erythrocytes with attached micronuclei in the blood of frogs from the study Kamchatka populations was revealed for the first time. This indicates chromosomal abnormalities induced by water mutagens. Sexual differences in the proportions of erythrocytes with micronuclei which were found in the Paratunka population suggest higher mutation frequencies in the erythrocytes of males than in females. The higher proportion of micronuclei detected in the erythrocytes of older frogs seems to have been accounted for by a cumulative effect of water xenobiotics. The morphophysiological indices (relative masses) of organs substantially contributed to the common variance of the study characters set. In the Paratunka population, the cytogenetic disorders in somatic cells revealed by micronuclei tests significantly contributed to sexual differences.

We systematized the literature data on reptiles' immune system and provided our own research on the immunohematological characteristics of venomous and non-venomous snakes at that review. The reptiles' lymphomyeloid complex is characterized by heterogeneity. The protection against to a wide range of habitat antigens is provided by two forms of immune response: innate and adaptive immunity. The innate immunity in comparison with adaptive responses responds more quickly and effectively. Protection against infections is represented by antimicrobial peptides, the complement system, a set of nonspecific leukocytes, and the formation of an inflammatory reaction, with a set of cytokine-like components. The mechanisms of adaptive immunity are cellular and humoral factors actions. The reptiles have a weakened reaction of transplant rejection. Humoral immune responses are carried out by B-lymphocytes. In this paper there are discussed the structure and functions reptiles' immunoglobulins, as well as the switching features of intracellular synthesis of immunoglobulins from one isotype to another. It was shown that the immune protection strategy is determined not only by the ontogenetic features of reptiles, but also by the input, size, and duration of exposure to antigens, by the range of external temperatures, by seasonality. The patterns of the immune response of venomous and non-venomous snakes to a complex of environmental factors were revealed. For the first time an immunohematological approach has been used to assess the status of the population of Elaphe dione in nature reserve. Biotopic and interspecific variability was found in the mechanisms of formation of the adaptive response at the population level.

For detection of rather large ionospheric structures (such as high-latitude ionospheric troughs, main ionospheric trough, etc.) using Global Navigation Satellite Systems (GNSS) we suggest employing the analysis of anomalous deviations in behavior of the absolute slant total electron content (TEC) on particular “GNSS receiver - GNSS satellite” lines of sight (LOSs). Using data of four high-latitude GNSS-stations, the proposed method allowed us to detect the 5 May 2013 high-latitude ionospheric trough (HLIT), determine its location and size, and follow the dynamics. The HLIT was located on the dayside within 25-185°E. Initially (04:40–06:00 UT), the HLIT equatorial wall and bottom were within 68-78°N and 70-80°N, respectively. The trough northern wall was not registered at this time, most likely due to insufficient number of LOSs. During the next hour (06:00–07:00 UT), the trough has moved 2-4° southward. Its bottom lay near 68-76°N; equatorial and polar walls were within 67-74°N and 77-78°N, respectively. The trough width was about 4°. At 07:00–08:00 UT, the HLIT structure and location remained almost the same. To interpret the observation results, we used the model for ionosphere-plasmasphere coupling (developed at the Institute of Solar-Terrestrial Physics SB RAS) to simulate the high-latitude ionosphere conditions on 4–6 May 2013. This simulation showed that on 5 May 2013, a high-latitude trough was formed on the dayside at 40-200°E and 78-85°N. The most likely reason for the formation of HLIT both in model calculations and in reality was a change in the magnetospheric convection in the high-latitude ionosphere caused by the moderate geomagnetic disturbances (substorms) on 4–5 May 2013. The trough location determined from the analysis of anomalous TEC deviations on particular LOSs was in good agreement with location of the high-latitude ionospheric trough obtained from numerical simulation. Thus, the analysis of anomalous deviations in TEC behavior on particular LOSs expands the GNSS potential in detecting large-scale irregularities in the ionosphere.