Shuman, Leonid A

Machikhin A., Guryleva A., Chakraborty A., Khokhlov D., Selyukov A., Shuman L., Bukova V., Efremova E., Rudenko E., Burlakov A.

AbstractToxic environmental pollutants pose a health risk for both humans and animals. Accumulation of industrial contaminants in freshwater fish may become a significant threat to biodiversity. Comprehensive monitoring of the impact of environmental stressors on fish functional systems is important and use of non‐invasive tools that can detect the presence of these toxicants in vivo is desirable. The blood circulatory system, by virtue of its sensitivity to the external stimuli, could be an informative indicator of chemical exposure. In this study, microscopic photoplethysmography‐based approach was used to investigate the cardiac activity in broad whitefish larvae (Coregonus nasus) under acute exposure to cadmium and phenol. We identified contamination‐induced abnormalities in the rhythms of the ventricle and atrium. Our results allow introducing additional endpoints to evaluate the cardiac dysfunction in fish larvae and contribute to the non‐invasive evaluation of the toxic effects of industrial pollutants on bioaccumulation and aquatic life.

Slavin A.E., Guryleva A.V., Bukova V.I., Shuman L.A., Burlakov A.B.

Selyukov A., Zhigileva O., Shuman L., Selyukova S., Bogdanova V.

The qualitative and quantitative composition of primordial germ cells (PGCs) and the genetic variability of embryos of the Coregonus nasus from the Ob river basin and domesticated population breeding outside the natural areal was examined. In the broad whitefish, typical, binuclear, polymorphic nuclei cells, as well as PGCs represented primary gonocytes during embryogenesis in clusters. When hatching larvae PGCs mitoses were noted only in domesticated juveniles. The genetic variability of embryos of the broad whitefish was studied by polymerase chain reaction of inter simple sequence repeats (ISSR-PCR). The high polymorphism of the broad whitefish cultured population was revealed. The proportion of polymorphic bands was 89.4%, Nei's genetic diversity was 0.32. Reproduction of the domesticated broad whitefish did not affect the overall level of polymorphism of neutral DNA markers. These findings suggest the preservation of cytomorphological and genetic diversity in C. nasus embryo from different sources.

Gashkina N.A., Moiseenko T.I., Shuman L.A., Koroleva I.M.

Bioaccumulation of the main pollutants in the organs of whitefish, as well as their haematological parameters, were examined dynamically over a 40-year period in historically contaminated Lake Imandra. A quantitative histological analysis was performed to assess the physiological state of whitefish and histopathologies of organs, as well as their physiological and biochemical functions in the current period of toxic load decline. Biological reactions of whitefish from the historically contaminated area have been greatly modified in contrast to those of whitefish from the never contaminated area of the lake, and this shift persisted even after approximately 20 years of toxic load decline. First, high antioxidant status supports the body's systems, smoothing over the negative consequences of metal toxicity, phagocytosis and inflammatory reactions. Moreover, the defence mechanism of whitefish from the historically contaminated area actively uses the oxidative systems of nonspecific immunity. Second, the adaptive strategy is aimed at improving gas exchange without compensatory proliferation of gill structure, which increases their functional surface and reduces the distance to the bloodstream, as well as increasing haemoglobin in maturing erythrocytes. Third, the higher efficiency of endo- and phagocytosis was confirmed by detecting increased monocytes and macrophages in the peripheral blood and decreased melano-macrophage centres in the fish kidney. Elevated accumulation of Fe, Cu, and Se may serve a sign of liver pathology, while elevated accumulation of Zn and Co already indicates kidney pathology, which is confirmed by histopathological alterations. • Biological reactions of whitefish from historically contaminated area have been modified: • high antioxidant status supports the body's systems. • oxidative systems of nonspecific immunity dominate in protective functions. • adaptive strategy is aimed at improving gas exchange and increasing haemoglobin in erythrocytes. • high efficiency of endo- and phagocytosis is typical for fish.

Shuman L.A., Selyukov A.G., Nekrasov I.S., Elifanov A.V., Yurchenko V.V.

Raw data were obtained from 250 specimens of roach Rutilus rutilus and 274 specimens of perch Perca fluviatilis at 15 sampling sites located from North to South Taiga. Fish sampling was performed using gill-nets with 22 and 28 mm mesh. Total and eviscerated weights, total and standard lengths, fish sex, gonad weight and maturity stage were recorded. Linear regression analysis of log-transformed total weight and total length values was performed. Regression slope and intercept were used to obtain length-weight relationships and mean condition factor values. Length-length relationships were calculated by the linear regression between the total and standard lengths. Gonadosomatic index was determined using the gonad weight and the total weight of fish. The data are useful for establishing biomass, fish growth patterns, relative condition of individuals within a sample or across populations.

Gashkina N.A., Moiseenko T.I., Shuman L.A., Koroleva I.M.

The mechanisms of fish adaptation to survival in the historically contaminated Lake Imandra were studied. The role of trace elements in the protective functions of the organism and their importance in the re-adaptation of organisms to improving the habitat was established. The lake whitefish (Coregonus lavaretus L.) unable to migrate for large distance was chosen as the object of research. The indices of red blood as an indicator of fish homeostasis, as well as the role of white blood cells in the activation of the immune system were examined. The causes of the occurrence of histopathologies of organs and tissues are explained. Data on the accumulation of trace elements in the body of fish from this lake are presented. The principal difference in the bioaccumulation of elements is the intense metabolism of Se. An elevated S to Se ratio indicates a high antioxidant status of fish from the historically contaminated part of the lake, while an increased accumulation of Fe, Cu, and Se can serve as a marker of liver pathologies, and Zn and Co, of kidney pathologies.

Martemyanov V.I., Mavrin A.S., Shuman L.A.

The Amur sleeper Perccottus glenii Dybowski 1877 is widespread in water bodies of Asia and Europe. The species is known to have a harmful effect on aquatic ecosystems, especially by damaging amphibian and fish populations. It was previously shown that based on the determination of the kinetic characteristics, it is possible to reveal the minimum concentrations of sodium, potassium, calcium, and magnesium in fresh water, which are necessary to maintain the ionic balance between the organism of freshwater hydrobiont and the external environment. This study revealed that the minimum concentrations of sodium, potassium, calcium, magnesium in water required to maintain the ion balance between the Amur sleeper organism and the environment are 0.0049–0.0058, 0.0004–0.0005, 0.0004–0.0005, 0.0001–0.0002 mmol/L, respectively. When the concentration of ions in the water is below the limit values, Amur sleeper cannot survive due to the predominance of the loss of ions from the organism. When the concentration of ions in the water is above the limiting values, the flow of ions into the organism is dominated due to the transport from the environment, allowing the accumulation of ions for growth and development.

Nekrasov I.S., Shuman L.A., Selyukov A.G.

This study analyzes the histological peculiarities of the internal organs of the lake form of Mongolian grayling Thymallus brevirostris (Kessler, 1879) caught in the cold-water mountain Lake Hindiktig-Khol (Tuva Republic, Russia) in the summer. The maturation of the females starts at 4+ years; the peak of their spawning activity is observed at 5+. Males mature 1 year earlier than females. In summer, in the ovaries of mature females, the older generation of germ cells is represented by oocytes at the phase of the cytoplasm vacuolization; the younger generation of cells is represented by numerous previtellogenous oocytes. The peak of spermatogenesis is observed in the testes. Significant pathomorphological changes are revealed in the gill epithelium which inhibit the respiratory function. Weakly expressed liver congestion and moderate basophilia of hepatocytes both indicate normal conditions in this lake.

Shuman L.A., Selyukov A.G., Nekrasov I.S., Kyrov D.N.

Histopathological changes in the gills, liver, kidneys and gonads and heavy metal accumulation have been studied in peled (Coregonus peled) from the Lower Ob basin. It has been shown that there is a relationship between pollutant concentrations in tissues and environment and the degree of pathology in the internal organs and that the morphofunctional status of fish has an effect on their reproductive potential. Impairment of reproductive parameters resulting from the accumulation of cadmium, mercury, and lead in fish tissues has been revealed. The ambiguous effect of pollution on the reproductive potential of the Ob peled population is discussed.

Selyukov A.G., Yelkin V.P., Samsonov A.N.

The materials of the anthropogenic impact on the surface waters of Russia, which reduces the morphofunctional status of fish and the fishery importance of reservoirs, are presented. Attention is focused on intoxication during the spring flood of the early stages of postembryonic development of fish with autumn-winter and spring spawning — salmon, whitefish, carp, perch. The literature data and original long-term studies of reducing the reproductive characteristics of fish populations and valuable fish farming facilities are presented. As a result, it is stated that there is a need to develop and improve commercial and breeding fish farming, focused on the formation of repair and breeding stocks. An urgent task for compensatory fish farming is to increase the toxicoresistance and reproductive potential of juveniles of valuable fish species released into nature. The article outlines the inevitability of turning to innovative biotechnologies in aquaculture. The structural qualities of water as a medium and the basis of aquatic biotechnologies are considered. Information is provided on the development of innovative approaches since 1991 by the team of Telos-Siberia LLC (since 2022, Positive Techno-Synthesis LLC) in the direction of increasing survival in early fish ontogenesis, optimizing their growth rate, development and formation of the reproductive system in normal and extreme natural and man-made, laboratory and industrial conditions. The mechanisms of magnetic catalysis involved in innovative Telos technologies are described.

Jovičić K., Đikanović V., Radenković M., Vranković J.S.

The application of biomarkers is often used to better understand the assessment of the toxicity in aquatic organisms within their natural environment. To this end, we examined the gills and liver of roach (Rutilus rutilus) to measure changes in the activity of the antioxidant enzymes superoxide dismutase, catalase (CAT), glutathione peroxidase, glutathione reductase and the phase II biotransformation enzyme glutathione-S-transferase (GST), as well as changes in the concentration of lipid peroxides (LPOs). Roach were collected at two localities, Veliko Ratno ostrvo and Višnjica (VIS), on the Danube River, where the concentrations of dissolved metals (Cu, Cd, Zn, Fe, Mn, Hg, Ni, As, Pb) in both fish tissues were quantified. This paper describes the integrated reaction of antioxidant enzymes and LPO levels of roach from two sampling localities in the Danube River. Principal component analysis revealed obvious differences of the antioxidant biomarkers investigated between tissues and localities, while integrated biomarker response showed that the liver of the VIS locality had the stronger antioxidant biomarker response. Despite the concordant hypothesized antioxidant induction at the VIS locality in both tissues studied, the effects as a sign of contaminant exposure appear to be mediated in part by suppression of the antioxidant system, with CAT and GST as potential candidate tissue toxicity biomarkers of contaminants.

Novikov M.A., Gorbacheva E.A., Kharlamova M.N.

The aim: to study the amount of cadmium found in muscle tissue and liver of the main commercial fish species of the Barents Sea.Research material was comprised of fish samples collected during the expeditions of N.M. Knipovich «PINRO» in the Barents Sea in 2009–2021. The study was based on muscle and liver samples taken from cod, haddock, long rough dab, Greenland halibut, plaice and spotted catfish. Over 1500 samples were analyzed.Novelty: for the first time a comparative analysis of Cd concentration in six commercial fish species of the Barents Sea was run and background readings were provided using such a big amount of data.Methods used: the content of Cd in fish samples was measured using Shimadzu (Japan) Atomic Absorption Spectrophotometer (AAS). Statistical data processing and charting were done using MS Excel and application software package of Statistica 13.The results show that the average content of Cd in muscle and liver of the examined fish did not exceed the established sanitary standard for the maximal concentrations of 0.2 and 0.7 mg/kg of wet weight, respectively. No evidence of anthropogenic contamination of the studied species by cadmium was found. The cadmium concentrations in liver was 11–17 times higher than in muscle. The total content of Cd in muscle and liver demonstrated a high variability (dispersion). The main reason for this variability is differences in the diet and feeding habits of the fishes. The cadmium content in muscle tissues is species-specific. The liver is capable of removing Cd from the body actively. The study also found other factors influencing the cadmium concentrations, such as taxonomic affiliation and regional peculiarities (particularly, habitats and fishing areas).Practical significance: the acquired results were used to determine whether the commercial fishes meet the sanitary standards used in Russia.

Machikhin A.S., Titov S.A., Huang C., Guryleva A.V., Burlakov A.B., Zykova L.A., Bukova V.I.

Ribeiro O., Pinto M.Q., Tavares D., Ferreira-Cardoso J.V., Correia A.T., Carrola J.S.

Climate changes linked to extreme events pose a threat to freshwater biodiversity, impacting organs, behaviour, and reproduction. Moreover, these changes can be amplified by pollution. Copper sulphate (CuSO4) is used in agriculture and aquaculture, so the copper can reach streams, rivers, and lakes impacting fish. This study evaluated the combined effects of temperature and copper on gills and liver histology biomarkers and in the behaviour of Mozambique tilapia over 28 days. Tilapias were exposed to different water temperatures (25 °C and 32 °C) and CuSO4 concentrations (1.1 and 3.6 mg/L). Fish from the control group were exposed to water without copper sulphate and at 25 °C (within their optimum range). Histopathological analysis revealed significant tissue lesions, namely aneurysms and bending of gill lamellae, and hyalinization and vacuolization in the liver at the higher temperature and CuSO4 level. Moreover, behavioural observations revealed increased stress changes under the same conditions. These findings highlight the effects of fast climate change, and rising temperatures on copper toxicity, underlining the necessity for strict monitoring and regulation of copper use due to future climate change scenarios to protect aquatic ecosystems, ichthyofauna population and trophic web dynamics. This data also alerts for similar problems with other toxic metals or chemicals, at short term, in streams and rivers, under rapid climate changes and more frequent extreme events.

Gashkina N.A.

Metals are dispersed in natural environments, particularly in the aquatic environment, and accumulate, causing adverse effects on aquatic life. Moreover, chronic polymetallic water pollution is a common problem, and the biological effects of exposure to complex mixtures of metals are the most difficult to interpret. In this review, metal toxicity is examined with a focus on its impact on energy metabolism. Mechanisms regulating adenosine triphosphate (ATP) production and reactive oxygen species (ROS) emission are considered in their dual roles in the development of cytotoxicity and cytoprotection, and mitochondria may become target organelles of metal toxicity when the transmembrane potential is reduced below its phosphorylation level. One of the main consequences of metal toxicity is additional energy costs, and the metabolic load can lead to the disruption of oxidative metabolism and enhanced anaerobiosis.

Torronteras R., Díaz-de-Alba M., Granado-Castro M.D., Espada-Bellido E., Córdoba García F., Canalejo A., Galindo-Riaño M.D.

The aim of this work was to compare the potential induction of oxidative stress and the antioxidant enzymatic response after a short-term waterborne exposure to copper (Cu) and arsenic (As) with that of the nanoparticles (NPs) of these elements (Cu-NPs and As-NPs) in fish larvae of the species Dicentrarchus labrax. Larvae were grouped in several tanks and exposed to different concentrations of contaminants (0 to 10 mg/L) for 24 or 96 h under laboratory conditions. Copper and arsenic concentrations were analysed in larval tissues using ICP-MS. A set of oxidative stress biomarkers, including the levels of hydroperoxides (HPs), and superoxide dismutase (SOD) and catalase (CAT) activities were assessed. The trace element concentrations (mg/kg d.w.) in larvae ranged as follows: 3.28–6.67 (Cu at 24 h) and 2.76–3.42 (Cu at 96 h); 3.03–8.31 (Cu-NPs at 24 h) and 2.50–4.86 (Cu-NPs at 96 h); 1.92–3.45 (As at 24 h) and 2.22–4.71 (As at 96 h); and 2.19–8.56 (As-NPs at 24 h) and 1.75–9.90 (As-NPs at 96 h). In Cu tests, the oxidative damage (ROOH levels) was induced from 0.1 mg/L at both exposure times, while for Cu-NPs, this damage was not observed until 1 mg/L, which was paralleled by concomitant increases in SOD activity. The CAT activity was also increased but at lower metal concentrations (0.01 mg/L and 0.1 mg/L for both chemical forms). No oxidative damage was observed for As or As-NPs after 24 h, but it was observed for As after 96 h of treatment with 0.01 mg/L. A decrease in SOD activity was observed for As after 24 h, but it turned out to be increased after 96 h. However, As-NPs did not alter SOD activity. The CAT activity was stimulated only at 96 h by As and at 24 h by As-NPs. Therefore, the two chemical forms of Cu exhibited a higher bioaccumulation and toxicity potential as compared to those of As. Importantly, the association of both Cu and As in NPs reduced the respective trace metal bioaccumulation, resulting also in a reduction in the toxic effects (mortality and biochemical). Furthermore, the assessment of oxidative stress-related biomarkers in seabass larvae appears to be a useful tool for biomonitoring environmental-occurring trace elements.

Sushkov N.I., Kurian N.N., Anuchin S.N., Zaytsev S.M.

Elemental chemical analysis of aquatic organisms is necessary for biochemical and ecological studies and pollution monitoring. Most analytical methods suitable for this require dissolution of solid samples. However, nondestructive analysis is possible by x-ray fluorescence spectroscopy (XRF) and laser-induced breakdown spectroscopy (LIBS), the analytical capabilities of which are complementary. Results from XRF and LIBS for determination of several macro- and microelements (P, Cl, K, Ca; B, Mn, Fe, Cu, Zn, and Sr) in organs and tissues of fishes and aquatic plants (bream, pike, horsetail, and hornwort) were compared using calibration curves. Signals of elements were normalized to the intensity of incoherently scattered radiation (in XRF) and to that of the Balmer Hα emission line (in LIBS) to account for matrix effects. A comparison of the results with data from an independent analysis by inductively coupled plasma optical emission spectroscopy showed that LIBS was superior to XRF with respect to accuracy for relatively light elements (P, K, Ca, Mn, Fe, and Cu). The advantage switched to XRF for heavier elements (Zn and Sr). The combination of XRF and LIBS made it possible to broaden the range of measurable elements. In some cases (P, K, Mn, Fe, Zn, and Sr), chemical destruction of the sample was unnecessary, which was important for simplification of the analytical procedures.

Moiseenko T.I.

The paper analyzes the effect of ever increasing anthropogenic impacts on land waters and analyzes V.I. Vernadsky’s works on natural waters and their significance for assessing modern biogeochemical processes. The paper demonstrates the scale of the influx of chemical elements and compounds into the modern biosphere as a result of the emission of greenhouse gases, nitrogen and phosphorus dissemination, acid-forming gases, and metals. Key changes in some regions and the biosphere as a whole are highlighted. The consequences of anthropogenically induced processes are illustrated by the example of a remote Arctic region, the northern Kola Peninsula in Russia: the effects of climate warming and the acidification and eutrophication of the waters and their enrichment in metals. In the wake of V.I. Vernadsky’s ideas about the role of land waters in supporting the life necessities of the planet’s human population, approaches to assessing water quality from the standpoint of the ecological paradigm are described.

Moiseenko T.I.

The article considers the increasing of anthropogenic loads on surface waters. An analysis of the works of V.I. Vernadsky about natural waters and their importance in assessing modern biogeochemical processes. The scales of the input of elements and substances into the modern biosphere, such as the emission of greenhouse gases, the dispersion of nitrogen and phosphorus, acid-forming gases, as well as metals, are shown. Key changes covering regions and the biosphere as a whole are noted. Examples of the consequences of the development of anthropogenically induced processes in surface waters are given on the example of Arctic remote regions - the Kola North of Russia: the impact of climate warming, acidification, eutrophication and enrichment of waters with metals. Within the concept of V.I. Vernadsky about the role of natural waters in the life support of Planet population, approaches to assessing the quality of waters from the standpoint of the ecological paradigm are given.

Nikiforov-Nikishin A.L., Nikiforov-Nikishin D.L., Kochetkov N.I.

The state of the population of native fish species in three lakes of the Altai Mountains has been considered. The analysis of fish age and weight show that the populations of Coregonus peled Gmelin, 1788 peled demonstrate different growth dynamics in the studied reservoirs under conditions of oligotrophic mountain lakes. The age composition of fish differs in the reservoirs: for example, individuals of four age groups (from 1+ to 4+) are present in Lake Kedelu-Kol, while only yearlings are found in Lake Kidelu. A histological study of the liver and gills of fish detected the absence of significant abnormalities of parasitic and toxicological nature. The calculation of the histopathological index has demonstrated that the prevalence and severity of pathological abnormalities are significantly lower (p < 0.05) in Lake Kidelu. The study of the elemental composition of peled lens confirms the absence of a significant level of pollution of the studied reservoirs and the high quality of the aquatic environment. The presence of trace amounts of heavy metals in individual samples can be associated with the geomorphological peculiarities of the region that are involved in the formation of the hydrochemical composition of water of the studied lakes. The data obtained in the study indicate that the peled populations in isolated mountain lakes of Altai demonstrate a different degree of oppression in a number of traits.

Nikiforov-Nikishin A.L., Nikiforov-Nikishin D.L., Kochetkov N.I.

This paper examines the state of the population of a native fish species in three lakes of the Altai Mountains. Analysis of the age and weight composition showed that in the studied water bodies in conditions of oligotrophic mountain lakes the pelad Coregonus peled Gmelin, 1788 population showed different growth dynamics. The age distribution of fish varied in different lakes, so in Lake Kedelu-Kol individuals of four age groups (1+ …4+) were present, and in Lake Kidelu only yearlings were caught. Histological examination of the liver and gills of fish showed the absence of significant abnormalities, both of parasitic and toxicological nature. Calculation of the histopathological index showed that the prevalence and severity of pathological abnormalities were significantly lower (p  0.05) in Lake Kidelu. The analysis of the elemental composition of peled lens confirmed the absence of a significant level of pollution in the studied water bodies and the high quality of the aquatic environment. The presence in some samples of trace amounts of heavy metals may be associated with the geomorphological features of the region involved in the formation of the hydrochemical composition of the water of the studied lakes. The data obtained in the study indicate that the peled populations in the isolated mountain lakes of the

Krylov V.V., Sizov D.A., Machikhin A.S., Guryleva A.V., Tchougounov V., Burlakov A.B.

Deng Y., Hu T., Chen J., Zeng J., Yang J., Ke Q., Miao L., Chen Y., Li R., Zhang R., Xu P.

ABSTRACT Heart rate is a crucial physiological indicator for fish, but current measurement methods are often invasive or require delicate manipulation. In this study, we introduced two non-invasive and easy-to-operate methods based on photoplethysmography, namely reflectance-type photoplethysmography (PPG) and remote photoplethysmography (rPPG), which we applied to the large yellow croaker (Larimichthys crocea). PPG showed perfect synchronization with electrocardiogram (ECG), with a Pearson's correlation coefficient of 0.99999. For rPPG, the results showed good agreement with ECG. Under active provision of green light, the Pearson's correlation coefficient was 0.966, surpassing the value of 0.947 under natural light. Additionally, the root mean square error was 0.810, which was lower than the value of 1.30 under natural light, indicating not only that the rPPG method had relatively high accuracy but also that green light may have the potential to further improve its accuracy.

Volkov M., Margaryants N., Myalitsin D., Potemkin A., Guryleva A.

Svendsen E., Føre M., Randeberg L.L., Olsen R.E., Finstad B., Remen M., Bloecher N., Alfredsen J.A.

Understanding the tolerance limits of fish is crucial for developing aquaculture operations that ensure good animal welfare. However, there exist little data describing the physiological responses in farmed Atlantic salmon, much because the technological tools for taking such measurements have not existed. Recent advances in electronic implants have enabled concurrent measurement of electrocardiogram (ECG) and photoplethysmograms (PPG) in salmon that can be used for robust estimation of HR and oxygen saturation in arterial blood (i.e., SpO2/pulse oximetry) if appropriate strategies for motion artifact and light scattering compensation can be realized. To enable pulse oximetry for farmed Atlantic salmon (and fish in general), two experiments have been conducted. In Experiment 1, PPGs were obtained from salmon induced to swim at two different water currents under normoxic conditions. By using two water currents, the resulting data provided a foundation for developing methods for motion artifact compensation. Data from this experiment were also used to calculate an average light scattering parameter using the modified Beer–Lambert law, under the assumption that SpO2 was 100 % for individual fish. In Experiment 2, fish were placed in a swim tunnel and subjected to hypoxic conditions and corresponding changes in SpO2 were estimated using the motion artifact and light scattering compensation approaches from Experiment 1. Results show that the suggested compensation approaches gives SpO2 estimates within the expected range (95 % to 100 %) under normoxic conditions. Under hypoxic conditions, changes in SpO2 that coincide with experiment events were observed, demonstrating that PPGs can be used to quantify such changes. The results from this pilot study therefore extend the selection of physiological parameters feasible to measure using electronic implants for Atlantic salmon. In doing so, the scope for physiological measurements is extended such that an improved understanding of physiological responses and tolerances in Atlantic salmon farming can be acquired, and ultimately be used to improve animal welfare in fish production.

Guryleva A., Fomina D., Volkov M., Serdoteckova S., Danilycheva I.

Bhat R.A., Bakhshalizadeh S., Guerrera M.C., Kesbiç O.S., Fazio F.

As is well known, the pollution in the aquatic environment in which fish grow has a direct impact on aquaculture practices. Pollution in aquatic systems because of multiple adverse effects on fish metabolic processes, especially the reproductive systems.The goal of this study was to assess the severity of pollution impact in two different hatcheries, Verinag hatchery, Site 1 (S1) and Panzath hatchery, Site 2 (S2) in Anantnag region, using histopathological, ultrastructural, oxidative stress, genotoxic, and hormonal analysis in rainbow trout gonad (ovary). M&M: Fish were collected between May 2018 and April 2019 from two locations, Verinag hatchery (S1) and Panzath hatchery (S2), which were affected by heavy metals.The histological and ultrastructural examination of rainbow trout ovaries from the Verinag hatchery (S1) revealed normal structure in growing oocytes in rainbow trout at various stages based on morphological features while the fish ovaries in the Panzath hatchery (S2) showed various deformities and irregularly shaped oocytes. The surfaces of some of these oocytes were wrinkled, rough, or distorted. Apoptotic studies revealed that the frequency of apoptotic cells collected from S2 water was significantly increased in ovarian cells (P < 0.05). The activity of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) were found to be increased in fish collected from S1 but decreased in fish collected from S2. In S2 caught fish, malondialdehyde (MDA) levels were found to increase gradually, and the degree of heavy metal stress was positively correlated (p < 0.05). The comet assay was used to determine the induction of DNA damage in ovarian cells. The induction of DNA damage was found to be significantly higher (p < 0.05) in S2 fish specimens compared to fish from S1. On comparing the DNA damage of the rainbow trout from the two sampling sites, it was revealed that the fish is much more sensitive to aquatic contaminants. Regarding steroid hormones, higher levels of progesterone and estrogen were reported in the fish samples collected from S1 as compared to S2 captured fish.In conclusion, the comparative study of fish from two different sites viz. Verinag hatchery (S1) and Panzath hatchery (S2) revealed that S2 sampled fish suffered more heavy metal damage, including cellular deformities, apoptosis, oxidative damage, and altered steroid hormones.

Lin Y., Yu J., Wang M., Wu L.

The combined pollution of antibiotics and heavy metals has attracted a worldwide attention in the recent years. 4-epianhydrotetracycline (EATC) is the major degradation product of tetracycline (TC), which has been detected frequently in environment and its concentration is even higher than TC under some circumstances. Cadmium (Cd) is a common heavy metal contaminant and has highly toxic to organisms, plants and humans even at low doses. In the present study, zebrafish (Danio rerio) embryo toxicity test was performed to investigate the single and combined effects of EATC and Cd on aquatic organisms. Exposure to EATC and Cd at environmentally relevant concentrations had a series of hazardous impacts on the embryonic development, including lethality, hatching rate, heart rate and teratogenic effects. Compared to the contaminant existed alone, combined pollution produced stronger toxicity, which appeared as the decreasing of heart rate and hatching rate, and the increasing of malformation of zebrafish embryos. After 96 h exposure, the reactive oxygen species (ROS) levels in zebrafish embryos were increased significantly, revealing that EATC-Cd co-exposure resulted in potential oxidative stress-induced damage. Acridine orange (AO) staining showed that combined exposure resulted in stronger cell apoptosis. The potential health risks of the combined pollution of EATC and Cd should be paid more attention to higher level vertebrates and humans.

Volkov M., Machikhin A., Bukova V., Khokhlov D., Burlakov A., Krylov V.

AbstractOptical techniques are utilized for the non-invasive analysis of the zebrafish cardiovascular system at early developmental stages. Being based mainly on conventional optical microscopy components and image sensors, the wavelength range of the collected and analyzed light is not out of the scope of 400–900 nm. In this paper, we compared the non-invasive optical approaches utilizing visible and near infrared range (VISNIR) 400–1000 and the shortwave infrared range (SWIR) 900–1700 nm. The transmittance spectra of zebrafish tissues were measured in these wavelength ranges, then vessel maps, heart rates, and blood flow velocities were calculated from data in VISNIR and SWIR. An increased pigment pattern transparency was registered in SWIR, while the heart and vessel detection quality in this range is not inferior to VISNIR. Obtained results indicate an increased efficiency of SWIR imaging for monitoring heart function and hemodynamic analysis of zebrafish embryos and larvae and suggest a prolonged registration period in this range compared to other optical techniques that are limited by pigment pattern development.

Machikhin A.S., Guryleva A.V., Selyukov A.G., Burlakov A.B., Bukova V.I., Khokhlov D.D., Efremova E.V., Rudenko E.E.

Label-free quantitative analysis of the cardiovascular structure and function in wild fish is highly important and still unsolved problem. We developed a robust algorithm for bright field microscopy data processing, which allows reliable detection and quantification of circulatory system across the whole animal. We verified this technique by in vivo experiments on broad whitefish (Coregonus nasus) embryos. Calculated morphofunctional features of heart and vessels are quite specific due to low temperature embryonic development of this fish, and correspond well to the reference data obtained by ex vivo techniques. This research highlights the feasibility of non-invasive cardiovascular imaging and measurements valuable for behavioral, environmental, toxicological, drug discovery and many other studies.

Hu G., Wang H., Wan Y., Zhou L., Wang Q., Wang M.

Different pollutants usually co-exist in the natural environment, and the ecological and health risk assessment of agrochemicals needs to be carried out based on the combined toxicological effects of pollutants. To examine the combined toxicity to aquatic organisms, the effects of cadmium (Cd) and five pesticides (acetamiprid, carbendazim, azoxystrobin, chlorpyrifos, and bifenthrin) mixture on zebrafish (Danio rerio) larvae were assessed. The data from the 96-h toxicity test indicated that bifenthrin possessed the highest toxicity to D. rerio with the LC50 value of 0.15 mg L−1, followed by chlorpyrifos (0.36 mg L−1) and azoxystrobin (0.63 mg L−1). Cd (6.84 mg L−1) and carbendazim (8.53 mg L−1) induced the intermediate toxic responses, while acetamiprid (58.39 mg L−1) presented the lowest toxicity to the organisms. Pesticide mixtures containing chlorpyrifos and bifenthrin or acetamiprid and carbendazim showed synergistic impacts on the zebrafish. Besides, two binary combinations of Cd-acetamiprid and Cd-chlorpyrifos also displayed a synergistic effect on D. rerio. Our results offered a better idea of the mixed ecological risk assessment of Cd and different agricultural chemicals to aquatic organisms. Our findings better interpreted how the interaction between Cd and various agrochemicals changed their toxicity to aquatic vertebrates and provided valuable insights into critical impacts on the ecological hazard of their combinations.

Foldvik A., Kryuchkov F., Sandodden R., Uhlig S.

Recent identification of 6PPD-quinone as the chemical causing acute toxicity in coho salmon has led to substantial concern regarding the toxicity of this contaminant for other aquatic species. Environmental occurrence of 6PPD-quinone is probably high, because it is an oxidation product of a common tire rubber additive. Research on 6PPD-quinone toxicity in fish has revealed a rather unusual pattern, with closely related species exhibiting responses ranging from extreme sensitivity to no effect. Of 11 previously studied fish species, 6PPD-quinone was toxic to four. The species-specific toxicity of 6PPD-quinone complicates urgently needed environmental risk assessment. We investigated the acute toxicity of 6PPD-quinone in Atlantic salmon and brown trout alevins (sac fry). These species have previously not been tested for sensitivity to 6PPD-quinone. The fish were exposed in static conditions in eight treatments with initial concentrations ranging from 0.095 to 12.16 µg/L. Fish were observed for 48 h, and changes in concentrations of 6PPD-quinone were monitored throughout the experiment. No mortalities or substantial changes in behavior were recorded in either Atlantic salmon or brown trout. This provides an important first step in assessing effects of 6PPD-quinone on these economically and culturally highly important species. Environ Toxicol Chem 2022;41:3041–3045. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Redman N., Straus D.L., Annis E.R., Murray M., Good C.

Bacterial and fungal pathogens in recirculating aquaculture and egg incubation systems can cause elevated mortality and decreased production. Peracetic acid (PAA) is a relatively low-cost, safe, and effective disinfectant; however, its toxicity to early life stages of the Atlantic salmon (Salmo salar) has not been assessed. The 24-h LC50 value of PAA was determined for three early life stages of Atlantic salmon: eyed eggs, fry (~0.17 g), and fingerlings (~16.3 g). LC50 values were calculated using the Trimmed Spearman-Karber (TSK) method and Toxicity Relationship Analysis Program (TRAP). TRAP LC50 values for eyed eggs treated for 5 and 10 min were 781.5 and 485.0 mg/L PAA, respectively, while TSK LC50 values for eyed eggs treated for 5 and 10 min were 771.1 and 462.1 mg/L PAA, respectively. TRAP LC50 values for fry and fingerlings were 4.0 and 5.3 mg/L PAA, respectively, while TSK LC50 values for fry and fingerling were 4.1 and 5.3 mg/L PAA, respectively. The no observed effect concentration (NOEC) values for eyed eggs treated for 5 and 10 min were 500 and 300 mg/L PAA, respectively. These LC50 and NOEC values provide guidance for developing safe PAA treatment protocols Atlantic salmon eggs, fry, and/or fingerlings.

Ortúzar M., Esterhuizen M., Olicón-Hernández D.R., González-López J., Aranda E.

The presence of emerging contaminants in the environment, such as pharmaceuticals, is a growing global concern. The excessive use of medication globally, together with the recalcitrance of pharmaceuticals in traditional wastewater treatment systems, has caused these compounds to present a severe environmental problem. In recent years, the increase in their availability, access and use of drugs has caused concentrations in water bodies to rise substantially. Considered as emerging contaminants, pharmaceuticals represent a challenge in the field of environmental remediation; therefore, alternative add-on systems for traditional wastewater treatment plants are continuously being developed to mitigate their impact and reduce their effects on the environment and human health. In this review, we describe the current status and impact of pharmaceutical compounds as emerging contaminants, focusing on their presence in water bodies, and analyzing the development of bioremediation systems, especially mycoremediation, for the removal of these pharmaceutical compounds with a special focus on fungal technologies.

Maciag M., Wnorowski A., Mierzejewska M., Plazinska A.

Cardiotoxicity remains the most common reason for failure during drug development. Recently, the zebrafish (Danio rerio) model has emerged for the evaluation of drug-dependent cardiotoxicity and for the identification of cardioprotective molecules. However, it remains unknown how closely the zebrafish-based results may be translated to humans. To tackle this issue, we established embryonic zebrafish models of doxorubicin-, adrenaline- and terfenadine-induced cardiotoxicity with unified dosing regimen which eventually enabled head-to-head comparison of the drugs. Subsequently, we determined whether human cardioprotective medications - dexrazoxane, metoprolol, carvedilol and valsartan - are able to manage heart dysfunction in zebrafish. Our results indicated that doxorubicin, adrenaline and terfenadine elicited overt signs of cardiotoxicity in fish, and we further showed that the blockade of the renin-angiotensin system and, to a lesser extent, β-adrenergic system, ameliorated the heart disease in zebrafish. From the drug development standpoint, our work opens the possibility to determine the cardiovascular properties of tested compounds using the rapid and affordable zebrafish model.

Charlton P.H., Paliakaitė B., Pilt K., Bachler M., Zanelli S., Kulin D., Allen J., Hallab M., Bianchini E., Mayer C.C., Terentes-Printzios D., Dittrich V., Hametner B., Veerasingam D., Žikić D., et. al.

The photoplethysmogram (PPG) signal is widely measured by clinical and consumer devices, and it is emerging as a potential tool for assessing vascular age. The shape and timing of the PPG pulse wave are both influenced by normal vascular aging, changes in arterial stiffness and blood pressure, and atherosclerosis. This review summarizes research into assessing vascular age from the PPG. Three categories of approaches are described: 1) those which use a single PPG signal (based on pulse wave analysis), 2) those which use multiple PPG signals (such as pulse transit time measurement), and 3) those which use PPG and other signals (such as pulse arrival time measurement). Evidence is then presented on the performance, repeatability and reproducibility, and clinical utility of PPG-derived parameters of vascular age. Finally, the review outlines key directions for future research to realize the full potential of photoplethysmography for assessing vascular age.