Ultrastructure of the mesonephros of whitefishes from the Lake Baikal basin.

The article presents a study of the mesonephros ultrastructure of Baikal omul Coregonus migratorius, Baikal whitefish Coregonus baicalensis, and a cross between Baikal whitefish and humpback whitefish (C. baicalensis × Coregonus pidschian). The mesonephros ultrastructure was studied using electron microscopy methods. The results of the study show that the number of mature granulocytes is a systematic feature and does not depend on the ecology of fish. The quantitative characteristics of blood cells and the ultrastructural features of leukocytes in the mesonephros are associated with the functioning of the nonspecific defence system in fish. Morphological diversity of epithelial cells in nephron tubules is the ancestral characteristic of the modern omul population, associated with geological and climatic events in the history of Lake Baikal. The development of haematopoietic tissue in the mesonephros, the ultrafine structure of ion-transporting interstitial cells, as well as some ultrastructural features found in the nephron, reflect the adaptive capabilities of the species to live in the ultra-deep Lake Baikal.

Responses of zebra and quagga mussels to copper and tribytiltin exposure: Bioconcentration, metabolic and cardiac biomarkers.

One of the top ecological priorities is to find sensitive indicators for pollution monitoring. This study focuses on the bioconcentration and responses (condition index, survival, oxygen consumption, heart rates, and oxidative stress and neurotoxic effect biomarkers) of mussels from the Volga River basin, Dreissena polymorpha and Dreissena bugensis, to long-term exposure to toxic chemicals such as tributyltin (TBT, 25 and 100 ng/L) and copper (Cu, 100 and 1000 µg/L). We found that TBT was present in the tissues of zebra and quagga mussels in comparable amounts, whereas the bioconcentration factor of Cu varied depending on its concentration in water. Differences in responses between the two species were revealed. When exposed to high Cu concentrations or a Cu-TBT mixture, quagga mussels had a lower survival rate and a longer heart rate recovery time than zebra mussels. TBT treatment caused neurotoxicity (decreased acetylcholinesterase activity) and oxidative stress (increased levels of thiobarbituric acid reactive substances) in both species. TBT and Cu levels in mussel tissues correlated positively with the condition index, but correlated with the level of acetylcholinesterase in the mussel gills. The principal component analysis revealed three main components: the first consists of linear combinations of 14 variables reflecting TBT water pollution, TBT and Cu levels in mussel tissues, and biochemical indicators; the second includes Cu water concentration, cardiac tolerance, and mussel size; and the third combines weight, metabolic rate, and heart rates. Quagga mussels are less tolerable to contaminants than zebra mussels, so they may be used as a sensitive indicator.

Histology and Ultrastructure of the Nephron and Kidney Interstitial Cells in the Atlantic Salmon (Salmo salar Linnaeus 1758) at Different Stages of Life Cycle.

This article presents data on the mesonephros histology and ultrastructure in the Atlantic salmon from the Baltic Sea and Barents Sea populations, with an emphasis on comparisons between the following ontogenetic stages: parr, smolting, adult life at sea, the adults' return to their natal river to spawn, and spawning. The ultrastructural changes in the renal corpuscle and cells of the proximal tubules of the nephron occurred as early as the smolting stage. Such changes reflect fundamental alterations during the pre-adaptation to life in saltwater. In the Barents Sea population, the adult salmon sampled in the sea had the smallest diameters of the renal corpuscle and proximal and distal tubules, the most narrow urinary space, and the thickest basement membrane. In the group of salmon that entered the mouth of the river and spent less than 24 h in freshwater, the structural rearrangements occurred only in the distal tubules. Better development of the smooth endoplasmic reticulum and a greater abundance of mitochondria in the tubule cells were observed in the adult salmon from the Barents Sea compared to those from the Baltic Sea. Cell-immunity activation was initiated during the parr-smolt transformation. Another pronounced innate-immunity response was registered in the adults returning to the river to spawn.

Proteomics Analysis in Japanese Medaka Oryzias latipes Exposed to Humic Acid Revealed Suppression of Innate Immunity and Coagulation Proteins.

Humic acids (HA), one of the major components of dissolved organic matter, can interfere with different metabolic pathways in aquatic animals, causing various biological effects. This study aimed to provide a molecular basis for HA-related responses in fish by analyzing changes in the blood plasma proteome following short-term exposure to environmentally relevant HA concentrations using the Japanese medaka Oryzias latipes Hd-rR strain as a model organism. Proteomics data were obtained by high-performance liquid chromatography with tandem mass spectrometry analysis employing a label-free quantification approach. HA caused dysregulation of proteins involved in various biological processes, including protein folding, signaling, transport, metabolism, regulation, immune response, and coagulation. The majority of the differentially abundant proteins were down-regulated, including those involved in humoral immunity and coagulation. HA caused the decrease of the complement cascade and membrane attack complex proteins abundance, as well as proteins participating in activation and regulation of secondary hemostasis. The most pronounced suppression was observed at the highest tested HA concentration.

Data on length-weight and length-length relationships, mean condition factor, and gonadosomatic index of Rutilus rutilus and Perca fluviatilis from the Ob River basin, Western Siberia.

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.

Unique and ancestral features in trunk kidney microanatomy and ultrastructure of omul Coregonus migratorius.

This study presents novel data on the microanatomy and ultrastructure of the omul Coregonus migratorius trunk kidney. Adult individuals of C. migratorius were sampled in the Barguzin Bay of Lake Baikal. Active leuko- and erythropoiesis were found in the interstitium of the mesonephros. For the first time, cells with radially arranged vesicles have been described in the renal interstitium of C. migratorius. The quantitative characteristics of blood cells and ultrastructural parameters of leukocytes reflected the functioning of the non-specific defence system in the organism. The share of the renal interstitium, morphological diversity of the epithelial cells of the nephron tubules, the ultrastructural features of the renal corpuscles and nephron tubules and the number of mitochondria in leukocytes and ion-transporting cells were typical for representatives of the whitefish Coregonus lavaretus complex and thus considered ancestral features of the present-day C. migratorius population reflecting its adaptive potential to living in an ultra-deep Lake Baikal.

Dataset on the effects of environmentally relevant humic acid concentrations on the liver protein profile in Japanese medaka (Oryzias latipes).

The data were obtained by a label-free quantification approach from a shotgun proteomics experiment, using STrap sample processing technique for protein digestion and high-performance liquid chromatography with tandem mass spectrometry (HPLC-MS/MS) for peptide analysis. MaxQuant data processing was used to obtain proteomics data. The dataset reflects changes in the liver protein profile of Japanese medaka exposed to 0, 5, 40 and 80 mg/L nominal concentrations of Sigma-Aldrich humic acid for 96 h. Actual concentrations of humic acid were measured using the potassium dichromate photometric method and reported in mg organic carbon/L. These proteomics data are relevant for further insights into fish stress responses to humic substances-related challenge.

Biochemical and respiratory parameters in a gastropod Radix balthica exposed to diclofenac.

Diclofenac, an anti-inflammatory drug, is often detected in natural waters in the ng/L to µg/L range, posing a threat to aquatic organisms. The study focused on the effects of diclofenac in a gastropod mollusk Radix balthica. A 72-h exposure to environmentally relevant concentrations of diclofenac caused deviations from the baseline activities of the studied enzymes in the digestive gland of snails. Acetylcholinesterase activity was induced by the end of exposure, with the most pronounced increase at 3 µg/L. Results on glutathione-S-transferase activity were nonuniform, and no significant variations were observed in thiobarbituric acid reactive substances concentrations, indicating that diclofenac did not cause oxidative stress in the digestive gland of R. balthica at 0.04-4 µg/L range. Diclofenac lowered the oxygen consumption rate in snails in a concentration-dependent manner. At concentrations ≥0.9 µg/L, animals attempted to switch aquatic respiration to breathing air to regulate their metabolic needs. The study showed that diclofenac at environmentally relevant concentrations affected the fitness of R. balthica.

Biodiversity of a boreal mire, including its hydrographic network (Shichengskoe mire, north-western Russia).

BACKGROUND: The paper is based on the dataset whose purpose was to deliver, in the form of GBIF-mediated data, diverse materials on the biodiversity of a large mire, Shichengskoe mire (Vologda Region, north-western Russia), including its various mire sites and intra-mire water bodies. The dataset was based on our materials collected for two decades (from 2000 to 2021) in different parts and biotopes of the Shichengskoe mire and complemented by scarce data obtained previously by other researchers. The data contain materials on the diversity of Animalia (2886 occurrences), Bacteria (22), Chromista (256), Fungi (111), Plantae (2463) and Protozoa (131). Within the study period, the most detailed and long-term biodiversity studies were carried out for higher plants and invertebrates. On the other hand, the data on the composition of lichens, protozoa, algae, basidiomycetes, some groups of invertebrates and, to a lesser extent, lichens and vertebrates are far less comprehensive and require further substantial research efforts. The list includes occurrences from both the peatland (mire sites and mire margins different in typology) and the objects of the mire hydrographic network. In a standardised form, this article summarises both already published (mainly in Russian) and unpublished materials. NEW INFORMATION: The paper summarises the results of long-term research on the biodiversity of a boreal mire, including its hydrographic network. A total of 5869 occurrences were included in the dataset published in the Global Biodiversity Information Facility (GBIF, gbif.org) for the first time. According to the GBIF taxonomic backbone, the dataset covers 1358 taxa, including 1250 lower-rank taxa (species, subspecies, varieties, forms) and 108 taxa identified to the genus level. Several species found in the Shichengskoe mire, mainly belonging to Bacteria, Chromista and Protozoa, have never been listed in GBIF for the territory of Russia before. The overwhelming majority of occurrences and identified species came from the territory of Shichengskiy Landscape Reserve. Due to our work, this Reserve is now the most studied regional reserve in the Vologda Region with respect to biodiversity. By the number of revealed species, it is close to two federal protected areas: Darwinskiy State Nature Biospheric Reserve and National Park "Russkiy Sever".

Data on length-weight relationships and mean condition factor for Abramis brama and Perca fluviatilis.

Data on total weight and standard length of freshwater bream and perch, two of the most abundant fish species in the Volga River basin, were collected monthly from April 2016 to May 2017. Fish were caught using gill-nets with 50 and 80 mm mesh sizes. Linear regression analysis of log-transformed values was performed. Regression slope and intercept were used to obtain length-weight relationships and mean condition factors. The data can be used for calculation of the relative weights of given species and further efforts to develop a mathematical model for the Volga River ecosystem.

Data on chemical characteristics of waters in two boreal Sphagnum mires (North-Western Russia).

The dataset contains chemical parameters of waters in different mire water bodies (fen strip, bog stream, Sphagnum hollows, hollow-pools, intra-mire lakes, drainage way). Data were collected once a month from May till September 2012 and in May, July and September 2013 and 2014 in Shichengskoe and Alekseevskoe-1 mires (Vologda Region, Russia). Water samples were kept in a cooling bag and transported to the laboratory within a day. Prior to analyses, water samples were filtered (pore size 90 µm). Colour of water, pH, permanganate value, dry residues, and total iron, manganese, carbonate, phosphate, sulphate and nitrate ion concentrations were measured. Data were obtained by the atomic absorption spectrometry and spectrophotometric and titrimetric methods. The pH values varied from 3.7 in Sphagnum hollows to 6.9 in a bog stream and 7.2 in a primary intra-mire lake. The minimum permanganate value of 5.6 mg O/L was registered in a bog stream, the maximum of 150.4 mg O/L in a weakly waterlogged Sphagnum hollow. Dry residue values varied in a range of 35 mg/L in a large hollow-pool to 315 mg/L in a flow-through fen strip. The data are useful for investigating chemical composition of waters in different mire water bodies and the heterogeneity of these abiotic factors.

Data on air temperature, relative humidity and dew point in a boreal Sphagnum bog and an upland site (Shichengskoe mire system, North-Western Russia).

The dataset contains microclimate parameters including air temperature, relative humidity and dew point measurements from a large wetland, Shichengskoe mire system, in Vologda Region, Russia, during four vegetation periods. Data were collected in 2013-2015 and 2017 using DT-171 data loggers (Elma Instruments). Data loggers were attached to the wooden posts at 0.5 m height from the surface. Continuous recordings were performed every 30 min providing 48 measurements of air temperature, relative humidity and dew point per day. The dataset presented in the article is of particular value to understanding the heterogeneity of abiotic parameters within mire systems.