Victoria V. Yurchenko

Glyphosate and its primary metabolite aminomethylphosphonic acid (AMPA) are widely detected in aquatic environments, yet their combined effects on fish remain insufficiently understood. This study used label-free blood plasma proteomic profiling to explore molecular patterns associated with 14-day exposure of juvenile common carp (Cyprinus carpio) to environmentally relevant concentrations of glyphosate (100 µg/L), AMPA (100 µg/L), and their mixture (50 + 50 µg/L). Across the three exposure groups, 41 proteins of interest showed pronounced abundance differences relative to the control based on fold-change selection criteria. These proteins were mainly associated with immune recognition, innate immune and complement-associated functions, coagulation and extracellular protease regulation, lipid/sterol transport, and extracellular matrix organization. In the mixture group, proteins of interest spanned several functional categories, suggesting that combined exposure deserves further attention in future studies of plasma-level responses to glyphosate and AMPA. Overall, these findings provide preliminary insights into blood plasma protein patterns associated with systemic responses of fish to glyphosate, AMPA, and their mixture at environmentally relevant concentrations and highlight the importance of considering parent compounds, metabolites, and their co-occurrence when assessing the potential biological effects of herbicide contamination in aquatic ecosystems.

Length-weight relationships were estimated for muksun Coregonus muksun, broad whitefish C. nasus, peled C. peled, humpback whitefish C. pidschian, tugun C. tugun, sardine cisco C. sardinella, nelma Stenodus nelma, and Arctic char Salvelinus alpinus. Fish were sampled between 2011 and 2013 using gillnets. Total lengths and weights were measured, common logarithms of the lengths and weights were calculated, and a linear regression analysis was performed using Sprugel’s correction factor. Studentized residual statistics was used to detect outliers. The fitted models explained 89.5% (in muksun) to 99.7% (in broad whitefish) of the variability in total weight. These length-weight relationships can be used in future studies to explore fish growth among areas and years or determine the condition of fish across populations or species.

Fish reared under seminatural conditions can be challenged by exposure to herbicides. Farming facilities relying on the surrounding area’s water quality can be affected by glyphosate and aminomethylphosphonic acid (AMPA) contamination. This review summarizes findings on how glyphosate and AMPA in the amounts registered in surface waterbodies affect redox status and biotransformation in fish and covers the aspect of diet supplementation for oxidative stress relief. Environmentally relevant concentrations of glyphosate and AMPA can alter the transcription and catalytic activities of antioxidant enzymes, decrease the content of reduced glutathione, and increase the accumulation of lipid peroxidation products, all of which are signs of a redox imbalance. Glyphosate has been shown to affect complex I in the mitochondrial respiratory chain and dysregulate iron transport-related genes, causing redox disturbance. Relatively high but environmentally realistic glyphosate concentrations can initiate the induction of cytochrome P450 biotransformation enzymes, alter the regulation of ABC exporters, and cause the inhibition of the redox-sensitive Nrf2 signaling pathway. Studies on reducing herbicide toxicity through dietary supplementation are a promising area of research. Natural functional supplements have been proven to have great potential for mitigating glyphosate-induced oxidative stress and thereby improving fish health, which in turn means maintaining productivity in fish farms that use natural water. However, data on the effects of AMPA on fish are scarce, and studies on the alleviation of its toxicity in fish are lacking. Considering the variety of AMPA contamination routes, one cannot underestimate the need for further research.

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.

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.

The analysis of changes in the liver proteome of the Japanese medaka Oryzias latipes Hd-rR strain following 96-hour exposure to humic acid was carried out. Humic acids are one of the major components of dissolved organic matter in surface waters. These substances can interfere with different metabolic pathways in aquatic animals, causing various biological effects. Proteomics data were obtained by high-performance liquid chromatography with tandem mass spectrometry analysis employing a label-free quantification approach. Liver proteome changes showed that HA exposure can dysregulate proteins with various functions, including cytoskeletal proteins and those involved in RNA metabolism, signal transduction, ATP, sphingolipid and prostaglandin synthesis, protein repair, cholesterol efflux, and xenobiotic metabolism. Furthermore, high HA concentration caused up-regulation of DIABLO, the protein of the mitochondrial apoptotic pathway.

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.

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.