Changes of the serotonergic system activity in fish tissues during an increase of water salinity

Changes of environment parameters produce essential effects on the serotonergic system activity in the body tissues. This paper describes study of the serotonergic system activity in various tissues of half-migratory fish - the Caspian roach Rutilus rutilus caspicus and the bream Abramis brama orientalis - caught in the fresh and brackish water. Using the method of indirect solid-phase ELISA test, the serotonergic system activity was assessed by determining in the studied fish tissues of the amount of serotonin-modulating anticonsolidation protein (SMAP) that is in the linear correlation with serotonin level. A significant change of the SMAP level in the Caspian roach and bream brain was found under effect on increased water salinity. Analysis of the SMAP amount in the bream liver did not reveal any differences in the animals caught in the brackish and fresh water. At the same time, in the bream gill there was a small rise of the SMAP content in the fish caught in the brackish water. The revealed in this experiment elevation of the SMAP amount in the Caspian roach and bream brain reflecting a corresponding increase of the serotonergic system activity indicates involvement of adaptive readjustments in the animal body.     

Adaptive increase of level of serotonin-modulated anticonsolidational protein in tissues of semimigratory and migratory fish at increase of water salinity

The article deals with studies of serotonergic system activity in different tissues of semimigratory fish—the Caspian roach (Rutilus rutilus caspicus) and the carpbream (Abramis brama orientalis)—and of migratory fish—shemaya (Chalcalburnus chalcoides) caught in fresh and brackish waters, as well as in the common carp (Cyprinus carpio L.) tissues under effect of brackish water in model experiments. Using the indirect solid-phase ELISA-test, the serotonergic system activity was evaluated by measuring in the tissues of the studied fish the serotonin-modulated anticonsolidation protein (SMAP) which is in linear relationship with the serotonin level. There was found a significant elevation of SMAP levels in brains of the Caspian roach, carpbream, shemaya, and the common carp under action of increased water salinity. A revealed increase of the SMAP content in brain of the Caspian roach, carpbream, shemaya and the common carp under action of increased water salinity reflects the corresponding elevated activity of the serotoninergic system and indicates involvement of adaptive readjustments in the animals’ body.     

Role of the brain in adaptation of the common and golden carps to adverse factors of chemical origin

Using an indirect solid-phase immunoassay (ELISA test), cytochrome P-450, serotoninmodulated anticonsolidation protein (SMAP) and 70-kDa heat shock protein (HSP70) levels were analyzed in the brain and liver of the common carp Cyprinus carpio L. and golden carp Carassius auratus caught in reservoirs of the Arpachay river (clean zone) and Araks river (polluted zone) in Nakhchivan Autonomous Republic of Azerbaijan. Upregulation of cytochrome P-450 (p < 0.05) and SMAP (p < 0.01) in the common carp brain and downregulation of cytochrome P-450 (p < 0.05) and HSP70 (p < 0.05) in the golden carp liver were detected in fish caught in the Araks river reservoir as compared to levels of the same substances in fish from the Arpachay river reservoir. It is concluded that the brain plays a regulatory role in adaptation of animals to adverse environmental conditions and in protection of tissues from negative effects of pollutants.     

Antimutagenic activity of serotoninergic system and underlying mechanisms in fry of sturgeon and goldfish

The paper deals with antimutagenic body activity and its underlying mechanisms. The experiments carried out on the one-year old sturgeons (Acipenser gueldenstaedti persicus) and goldfish (Carassius auratus) have shown that intramuscular administration of serotonin-modulated anticonsolidation protein (SMAP) leads to a twofold decrease of erythrocyte mutagenic alterations (the micronuclear test, p < 0.01) caused by action of benthic deposits (0.8 ml/l, 3 days) polluted with industrial wastes. Exposure of goldfish in water contaminated with crude oil (500 mg/l, 3 days) led to a sharp rise of the content of the 70 kDa brain protein fraction (p < 0.001); these water-soluble proteins are assumed to belong to heat shock proteins (HSP). At the same time, in the brain of the studied animals there was observed a simultaneous increase of the SMAP content (p < 0.001). After 3 h, intracerebral SMAP administration to goldfish increased significantly the 90 kDa protein fraction content (p < 0.01), probably HSP90, in the electrophoretic profiles of the brain water-soluble proteins. Thus, the obtained results indicate that the body serotoninergic system has the antimutagenic activity providing protection of cells from action of harmful environmental factors by an enhancement of synthesis of proteins suggested to belong to HSP.     

Specific features of expression of aspartate aminotransferase genes in early development of some cyprinid fishes and their intergeneric F1 hybrids

Temporal parameters of expression of the aspartate aminotransferase gene Aat-1 parental alleles were studied in early development of intergeneric reciprocal F1 hybrids of the bream, roach, and blue bream. When the first Aat-1 expression was timed to the early stages (late blastula-gastrula), the gene parental alleles were activated asynchronously according to the maternal types (blue bream × roach hybrids). When the first Aat-1 expression was timed to later stages (yolk sac resorption), the parental alleles were activated synchronously (bream × roach, roach × bream, and roach × blue bream hybrids). The pattern of activation of embryonic genes is determined by the maternal environment and the influence of allele interactions is not excluded: Aatf/Aat-sl (bream × roach, roach × bream, and roach × blue bream) and Aat-sl/Aat-med (blue bream × roach).     

Feeding of benthophagous fish in the Chogray Reservoir

Data on feeding of the bream Abramis brama, roach Rutilus rutilus, and white bream Blicca bjoerkna in Chogray Reservoir in 2010 and 2012 are presented. The main diet of bream consists of Chironomidae, and the diet of roach and white bream consists of the bivalve mollusk Dreissena polymorpha.     

Character of changes in serotonin-modulating anticonsolidation protein and cytochrome P-450 in tissues of Alburnoides bipunctatus eichwaldi caught in the rivers of Azerbaijan Republic

The work was designed to investigate the levels of a novel serotonin-modulating anticonsolidation protein (SMAP), which activity directly depends on serotonin level, and biomarker cytochrome P-450 in the liver, gills and brain of Alburnoides bipunctatus eichwaldi caught in Khudat, Agstafachay, Kura and Araz rivers running over the territory of Azerbaijan. Noticeable downregulation of cytochrome P-450 and SMAP was observed in the liver and gills of fish caught in Agstafachay river relatively to the values obtained for the fish from unpolluted Khudat river. The levels of cytochrome P-450 and SMAP in liver of fish from Kura and Araz rivers exhibited significant opposite changes: downregulation of cytochrome P-450 level vs. upregulation of SMAP level. In the brain of fish from Agstafachay river the cytochrome P-450 was found to be somewhat downregulated, whereas in the brain of fish from Kura and Araz rivers SMAP was significantly upregulated. The results obtained are analyzed from the standpoint of adaptation and disadaptation processes of water organisms to the effects of pollutants.     

Spatial organization of the spawning grounds of cyprinidae and the regulated flow of the Upper Ob

The study of Cyprinidae in the Novosibirsk Reservoir in periods of high, medium, and low water content demonstrated a high degree of dependence of the numbers of generations of aboriginal fish species on conditions of water level regulation in the spring period. A drastic water discharge via hydraulic structures leads to drying of spawning grounds and mass loss of eggs. The acclimatized species—bream Abramis brama—reproduces at deeper water sites of the water area, which determines its high numbers and domination in the structure of the fish community from the water body.     

Type of rheoreaction in the early ontogenesis of roach <Emphasis Type="Italic">Rutilus rutilus</Emphasis> (L.) as a factor determining its biotopic distribution

The specific features of rheoreaction in roach Rutilus rutilus (L.) larvae from open and protected shallows of the Rybinsk Reservoir have been studied. Data on length and weight of roach sampled at various habitats at B–E developmental stages are presented. It has been revealed that the type of roach larvae rheoreaction is a behavioral mechanism of their distribution over different types of habitats, not only in rivers but also in the waterbodies with slow water turnover rates—lakes and reservoirs. By the time of developmental stage E, this mechanism provides the sustainable spatial separation of juvenile fish, which in the future may lead to intrapopulation differentiation in roach.     

Influence of roundup herbicide on the activities of peptidases in the intestines of various fish species

It has been revealed that, as a rule, Roundup herbicide inhibits activities of peptidases in the intestine mucosa and chyme in various fish species, both benthivorous (common carp Cyprinus carpio, silver bream Blicca bjoerkna, roach Rutilus rutilus, and crucian carp Carassius carassius) and piscivorous (perch Perca fluviatilis, pike Esox lucius, and sander Sander lucioperca). The tolerance of peptidases to the herbicide is species-specific. The magnitude and vector of the effects of Roundup depend on its concentration and localization of an enzyme. In the mucosa, the enzymes of common carp and pike are most tolerant, while the enzymes of common carp, silver bream, and pike are most tolerant in the chyme.     

Diversity of life strategies of pikepech <Emphasis Type="Italic">Sander lucioperca</Emphasis> (L.) in the Lower Volga (by the data of microelement composition of otolithes)

Strontium (Sr) and calcium (Ca) contents and Sr/Ca ratios in otoliths of pikeperch Sander lucioperca have been studied by X-ray fluorescent microanalysis. A sample of 95 specimens from the Lower Volga region are studied. The fish were obtained in a section of the Akhtuba River at a distance of 250–279 km upstream from the Caspian Sea. Some specimens in the sample have low strontium content throughout the otolith. The other fish have increased both Sr content and Sr/Ca ratios in core zones of otolith or near its outer edge: the Sr/Ca ratio is over 6.00 × 10^–3, with a maximum at 10.02 × 10^–3. The fish with a low Sr/Ca ratio live in freshwater and demonstrate a resident life history strategy. Pikeperch that have increased ratios of Sr/Ca in outer zones of otolith demonstrate a migratory life history strategy. These fish leave the freshwater of the Volga and feed in brackish water of the Northern Caspian Sea. Some migratory fish migrate to the sea as underyearlings, stay in a brackish water for 1 year or less, and then return back to fresh water for the rest of its life. The other group migrates back and forth from freshwater to the sea several times during their life. Finally, some fish leave freshwater for 1–2 years, spending this time in the Northern Caspian Sea. The conclusion is that the pikeperch stock in the Lower Volga has a complicated composition and consists of freshwater (residents and rheodromic ones) and migratory (anadromous and semianadromous) fish.     

Serotonin-Modulating Protein Content as a Biomarker of Environmental Pollution

This work concerns the ELISA-test determination of the serotonin-modulating anticonsolidation protein (SMAP) content under industrial and oil pollution. Exposure of goldfish Carassius auratus in fresh water containing oil at concentrations of 100 and 500 ppm for 5 days leads to significant increase of the content of SMAP in the livers. These studies are conducted in parallel with micronucleus analysis of erythrocytes. It is shown that although SMAP content changes at this test oil concentration, changes do not occur in micronucleus amounts. While studying the SMAP content in the livers of wild-living gobies Neogobius fluviatilis taken from a polluted zone of the Caspian Sea, decrease of SMAP content and increase of micronuclei amount are noticed. So, short-term exposure of fish to oil pollution leads to increase of the SMAP content, whereas long-term exposure results in decrease of its content. The possibility of application of the SMAP as a biomarker of environmental pollution is discussed.     

Otoliths as object of EPR dosimetric research

Otoliths are the organs which fish use for hearing and keeping balance. Otoliths are the most calcified tissues in the fish body. In contrast to bones, otoliths are not affected by remodeling and, therefore, they are expected to accumulate any dose from ionizing radiation during lifetime. Therefore, EPR dosimetry with fish otoliths could be an important tool for dose reconstruction in radiobiology and radioecology. It could also provide useful information remediation actions to de-contaminate waterbodies. Consequently, in the present study, otoliths of three contaminated fish species (roach (Rutilus rutilus), pike (Esox lucius) and perch (Perca Fluviatilis)) were examined with Electron Paramagnetic Resonance (EPR) spectroscopy. The fish were caught at storage reservoirs of liquid radioactive waste from Mayak PA and from the upper reach of the Techa River, which have been contaminated with different levels of radionuclide activity concentrations. It is shown that the radiation-induced EPR signal of otolith is stable and characterized by a linear dose response. However, the slope of the calibration curve (corresponding to the radiation sensitivity of the material) is not the same for different species; this may be caused by differences in mineralization. The reconstructed doses were found to be in the range from undetectable (in fish from the upper stream of the Techa River) up to 265 Gy (in roach from the most contaminated waterbody). In parallel, otoliths were measured with β-counter to detect ⁹⁰Sr/⁹⁰Y. Samples were also tested on the presence of alpha-emitters, but no alpha activity above background could be detected. However, a significant activity concentration of ⁹⁰Sr was detected (from 1?×?10¹ to 2?×?10⁴ Bq/g). The EPR doses measured correlated with the ⁹⁰Sr activity concentration measured in the otolith samples.     

Evolutionary-physiological aspects of adaptation of the Pacific salmon fry of the oncorhynchus genus to migration to the sea water

A complex of adaptive changes occurring in the Pacific salmon fry in the process of migration to the sea is described, including behavior, ion content in carcasses, and morphological changes in Stannius bodies, gill epithelium, and nephron tubular epithelium. Participating in experiments with transfer from fresh water into a two-layer aquarium (the lower layer—sea water, the upper layer—fresh water) were smolts of chum salmon and underyearlings of cherry salmon as well as the trachurus and leiurus forms of the three-spined stickleback Casterosteus aculeatus. All fish, regardless of their salt preference, at once after placement into the two-layer aquarium, occupied the sea water zone, at the very bottom of the aquarium. After 1 h, there started brief excursions of cherry salmon and chum salmon to the upper, fresh water layer; however, both forms of the three-spined stickleback did not participate in these excursions. After 12 h, the chum salmon settled down in the lower, sea water layer, while the cherry salmon—in the upper, fresh water layer. Both forms of the three-spined stickleback never left the sea water layer and felt quite comfortably on the aquarium bottom. It seems that the high tolerance of the both stickleback forms to wide salinity limits allows them to choose the convenient position regardless of the water salt composition. By analyzing the material obtained for three years (2001–2003) on structure and functions of the gill epithelium chloride cells (CC), we have come to the conclusion that the fresh water fry of two salmon species, chum and cherry salmons, caught at the same time and practically in the same water reservoirs can be divided into three groups. The underyearlings of the cherry salmon as a rule are characterized by the thickened epithelium of secondary gill lamellae, but by a very small number of CC. In smolts of chum salmon, on the contrary, the epithelium is sufficiently thin, but enriched in the CC that demonstrate an active structure in the very beginning of migration to sea. However, with approaching the sea (and with an increase of terms of migration) the CC activity drops, but their amount does not change. And only after migration to the sea the CC activity rises again, although their amount seems to remain unchanged. The described peculiarities of behavior and of the ion composition regulation in the migrating salmon fry confirm the hypothesis that the salmons evolutionized in fresh water, that the Oncorhynchus genus appeared in large spaces of saltish waters, such as the Japan sea at the period of the early Pleistocene, and that learning of fry of the Oncorhynchus genus (for instance, of O. gorbuscha and O. keta) is the most specialized in the salmons migration to the sea, whereas the fresh water species of chars (Salvelinus) and of trouts (Salmo) are more primitive.     

Participation of serotoninmodulated anticonsolidation protein in mediation of action of adverse factors on lipid peroxidation level in tissues of sturgeon fry <Emphasis Type="Italic">Acipenser güldenstädti persicus</Emphasis>

The work analyzes participation of the serotoninergic system in correction of adverse effects of benthic deposits contaminated with industrial wastes on the level of lipid peroxidation (LPO) in the fry of the sturgeon Acipenser güldenstädti persicus. In the first series of the study, two intramuscular injections to the sturgeon fry of serotonin-modulated anticonsolidation protein (SMAP) that is in the direct correlation with the serotonin level led to pronounced normalization in the animal tissues of the LPO level whose increase was due to keeping the sturgeons in the fresh water contaminated with benthic deposits. In the second series of the study, administration to the animals of polyclonal anti-SMAP antibodies led to a significant increase of the LPO level in the tissues, similar to effects of the benthic deposits. It is concluded that adverse factors can produce their negative pro-oxidative effects on the organism tissues through a decrease of activity of the serotoninergic system, whereas an artificial increase of the serotoninergic system activity promotes correction of the oxidative stress.     

Impact of the Alien Species <Emphasis Type="Italic">Mnemiopsis leidyi</Emphasis> A. Agassiz, 1865 on Fish of the Caspian Sea

The data of long-term ecological studies (1999–2014) are used for assessing the impact of a new Caspian invader Mnemiopsis leidyi A. Agassiz, 1865 on marine and anadromous fish species. The introduction of the ctenophore and its massive development in the Caspian Sea have mainly affected planktophagous fish, especially the most abundant species anchovy sprat (Clupeonella engrauliformis Borodin, 1904) and sturgeons (Family Acipenseridae). Mnemiopsis leidyi is one of the main negative factors preventing the restoration of the populations of Caspian fishes, especially anchovy tyulka. The critical state of the resources of the spawning parts of sturgeon populations (Family Acipenseridae) has been reinforced as a result of the massive development of M. leidyi.     

Behavioral differences of various ecological groups of roach Rutilus rutilus and perch Perca fluviatilis

The intrapopulation morphological and behavioral polymorphism of roach (Rutilus rutilus) and perch Perca fluviatilis) was studied. It was shown that marker indices for distinguishing intrapopulation groups are the size of the mouth opening and the index of the body shape in roach and the coefficient of pigmentation in perch. Based on analysis of the data of indices, it was found that there are two ecological groups—coastal and pelagic in populations of roach and perch. Several behavioral differences in individuals of various ecological groups were revealed. Comparison of the defense reaction of perch individuals belonging to various ecological groups was performed. The assessment of the effects of hydrodynamic activity on the survival of perch individuals belonging to various ecological groups was made. Differences in the swimming capacity of juvenile roach developing under conditions of biotopes of various types were established. Suggestions were made on the mechanisms of formation of intrapopulation groups of roach and river perch.     

Biological features of common fish species in Olyutorsky-Navarin region and the adjacent areas of the Bering Sea: 3. Righteye flounders (Pleuronectidae)

Biological features of the seven abundant commercial species—the Pacific halibut Hippoglossus stenolepis, the Greenland halibut Reinhardtius hippoglossoides, the Alaska plaice Pleuronectes quadrituberculatus, the northern rock sole Lepidopsetta polyxystra, the yellowfin sole Limanda aspera, the flathead sole Hippoglossoides elassodon, and the Bering flounder H. robustus (Pleuronectidae)—have been studied for a 20-year period (1995?2015). These species are present in the northwestern Bering Sea in the summer–autumn season; they form the gatherings in Olyutorsky-Navarin region. The size-weight spectra of the fish caught by different fishing gear has been analyzed, the peculiarities of the linear growth and the weight gain, as well as the spawning period and scale and the spawning conditions, have been described. The largest halibut specimens have been registered in the bottom setlines and gill nets, while flounders were in snurrevad catches; the smallest specimens have been observed in trawl catches. The abundant year-class in most of the studied species is seen well on the long-term plots of the fish size spectra and is tracked by the decrease of their biological parameters. The species that demand vast growing grounds (Pacific halibut, Alaska plaice, northern rock sole, and yellowfin sole) are characterized by a smaller average body size of the fish sampled in the coastal waters due to the prevalence of the young specimens in this area.     

Variability of Black and Caspian Sea sprat <Emphasis Type="Italic">Clupeonella cultriventris</Emphasis> (Clupeidae) growth in the contemporary range

The size and age composition of the population of Black and Caspian Sea sprat Clupeonella cultriventris, as well as the variation of the growth of fish in the reservoirs of the upper reaches of the Volga, are reported and a comparative analysis of group and individual variability of fish growth within the native (Caspian, Azov, and Black seas) and contemporary (formed due to invasion) ranges is presented. The degree of variability and the asymmetry of sprat body length distribution have been shown to increase under the conditions of large population sizes, deficit of food, and slow growth. Variability was also elevated near the borders of the range of the species, notwithstanding the abundance of food. It is shown that invasion of sea walnut comb jelly Mnemiopsis leydi into the Azov and Caspian Seas had so undermined feed base of sprat, that it is not only decreased its abundance and fecundity but also slowed growth of the fish.     

Sexual Dimorphism and Length–Weight Relationship of the Hairy Conger Eel <Emphasis Type="Italic">Bassanago albescens</Emphasis> (Anguilliformes: Congridae)

The present study reports the first reference on length-weight relationships (LWR) and sexual dimorphism for Bassanago albecens, caught as bycatch in the commercial fishery in the Argentine continental shelf. A total of 91 conger eels were examined. Female specimens (ranged from 371 to 661 mm total length—TL) have body length larger than males (from 396 to 537 mm TL), but the length-weight relationships allometry coefficient was 3.76 for both sexes. Three out of seven morphometric measurements differed between sexes, in particular head size characteristics. These biometric data and their relationships are relevant to the management and conservation of fish diversity and fisheries.