The pollution of world ocean is a serious threat to the biodiversity of flora and fauna. One of the most important sources of pollution are oil and oil products – every year more than 1 million tons of oil is spilled into the sea as a result of accidents during oil production or transportation. The teratogenic and carcinogenic effects of such oil components as benzopyrene is well known since the middle of the last century. However, after a large oil spill from “Exxon Valdez” tanker in 1989 it became clear that oil and its components have strong toxic effects in fish organism – and to a large extent these effects are caused by di- and tricyclic aromatic hydrocarbons, in particular phenanthrene. Field research have demonstrated that fish embryo and larvae are the most prone to the effects of oil – and the largest oil spills endanger the populations of important commercial fish species that spawn in this area. This review considers the influence of polycyclic aromatic hydrocarbons (PAH) on the physiology of various organ systems in fish. Particular attention is paid to the cardiotoxic effects of PAH which were recently discovered and which are potentially not only the main cause of animals’ death upon the spill of PAH into water, but also underlie the malformation of other organs.

The application of the classical selection of diatoms on the example of the genus Haslea is considered. The ability of some representatives of this genus to synthesize marennine and marennine-like pigments is interesting to researchers and owners of oyster farms because these unique pigments can colorise the tissues of mollusks in a greenish color and improve their organoleptic properties. It has been shown that marennine has antibacterial, antiviral, antioxidant and other biological activities. It is assumed that the efficiency of marennine biosynthesis can be increased by obtaining highly productive strains by selection, which was not previously carried out in diatoms. The assessment of the possibility and prospects of applying the methods of classical breeding in relation to representatives of the genus Haslea is given. It is shown that significant success has been achieved to date in the study of the life cycle, crossing systems and other features of the reproductive biology of representatives of the genus Haslea, which allows them to carry out classical selection by selection, hybridization and obtaining descendants of the next generation.

Apart from their functions in the nervous system of animals, neurotransmitters operate as regulatory agents and signals in diverse kingdoms of life. Many neurotransmitters at low concentrations exert specific effects on microalgae, predominantly functioning as algal growth stimulators. Neurotransmitters that promote microalgal biomass accumulation and enhance the synthesis of lipids, polysaccharides, and other valuable products are of much potential biotechnological interest in terms of projects aimed at producing “algal” drugs and food additives, as well as biodiesel and other kinds of biofuel. Some microalgal species synthesize their own neurotransmitters and/or facilitate their synthesis by the symbiotic microbiota in the gastro-intestinal tract and, therefore, are expected to promote human physical and mental health. Microalgae can exert neuroprotective effects; nevertheless, many microalgae produce toxins affecting the functioning of the nervous system.

In this work, the anti-inflammatory potential of secretory-excretory products (SEP) of gulltapeworm Dibothriocephalus dendriticus and ligula Ligula interrupta plerocercoids was studied for the first time in an in vitro model of LPS-induced activation of macrophages. A monocyte cell line derived from a patient with acute monocytic leukemia, THP-1, was used as a macrophage model. The anti-inflammatory properties of SEP were determined by the content of tumor necrosis factor (TNF) and interleukin-6 cytokines in the incubation medium using commercial kits for enzyme immunoassay. The results of our study indicated that SEP from L. interrupta plerocercoids have a pronounced anti-inflammatory effect, while SEP from D. dendriticus plerocercoids did not have such an effect. Next, we investigated the anti-inflammatory properties of L. interrupta SEP in a carrageenan-induced air-sac inflammation model in mice. A significant decrease in the volume of inflammatory exudate under the influence of L. interrupta SEP was found, as well as an increase in the level of the interleukin-6 cytokine. At the same time, SEP of L. interrupta had no effect on the number of cells per 1 ml of exudate, as well as on the level of the pro-inflammatory cytokine TNF. The low molecular weight fraction of L. interrupta SEP also increased the level of the anti-inflammatory cytokine interleukin-10, which indicates a more pronounced anti-inflammatory effect compared to the high molecular weight fraction. The results obtained, in general, indicate the anti-inflammatory properties of the SEP of L. interrupta plerocercoids. However, the mechanism of anti-inflammatory action has not been elucidated and requires further research.

High-resolution chlorophyll fluorescence light induction curves (OJIP transients) are widely used to assess the primary photosynthetic responses of phototrophic microorganisms. Chlorophyll fluorescence measuring methods coupled with microscopy techniques provide a promising opportunity to measure OJIP transients on individual algal cells, allowing scientists to investigate stress adaptation mechanisms related to reorganization of microalgae population or phytoplankton community. In this work, we first characterized the OJIP transients measured on individual algae cells using the original microfluorimeter and compared them with OJIP transients recorded in microalgae suspensions. Based on the results of the study, we proposed a method for analyzing OJIP curves of individual microalgae cells as well as ways to further improve microfluorimeters.

Pure cultures of 19 strains of spore-forming bacteria were obtained from the equipment surfaces of the Russian segment of the International Space Station. The study of morphological, cultural and physiological-biochemical properties of these bacteria allowed us to attribute all strains to the genus Bacillus. As a result of using MALDI-TOF methods and genome-wide sequencing, it was found that out of 19 bacillus strains, six belong to the species B. paralicheniformis, four to B. pumilus, four to B. subtilis, two to B. cereus and one to B. amyloliquefaciens. In accordance with the requirements and norms of EUCAST 2023, the resistance of bacillus strains obtained from the Russian segment of the International Space Station to antibiotics such as imipenem, meropenem, ciprofloxacin, levofloxacin, norfloxacin, vancomycin, erythromycin, clindamycin and linezolid was studied. Resistance to erythromycin was found in 11 strains of bacilli and five strains showed resistance to clindamycin. Only one strain showed resistance to imipenem, levofloxacin and norfloxacin, respectively. Analysis of the complete genome of bacterial strains in which resistance to erythromycin and (or) clindamycin was found made it possible to establish that resistance to these antibiotics in B. paralicheniformis strains SE71, SE131, SE181, SE182, SE183 provides the ermD antibiotic resistance gene. In B. cereus SE43, resistance to erythromycin encodes the mphL gene.

Fluoroquinolone antibiotics such as ciprofloxacin have been actively used in medical practice, including the COVID-19 pandemic, to suppress adverse bacterial infections. Widespread application and improper disposal have resulted in the ubiquity of antibiotics in the environment, which can affect aquatic life, including phytoplankton. The effect of fluoroquinolone antibiotics on the photosynthetic processes of marine diatoms, which are the main producers in marine ecosystems, has been little studied. In this work the effect of the antibiotic ciprofloxacin on the primary photosynthetic processes in the marine diatom Thalassiosira weissflogii was studied. It has been shown that ciprofloxacin affects the functioning of PSII, preventing the transfer of absorbed energy from the excited antenna chlorophyll molecules to the PSII RC (φDo). Under the influence of ciprofloxacin, a decrease in the efficiency of electron donation to P680+ (FV / FO), inhibition of the quantum yield of PSII (FV / FM), a decrease in the proportion of active RCs (ABS / RC), and an increase in the dissipation of absorbed energy in RCs (DIo / RC) were revealed. It has been shown that the mechanism of action of ciprofloxacin is associated with damage of PSII RC. Ciprofloxacin enhances the photosensitivity of microalgae and causes an increase in lipid peroxidation products. It is proposed to apply the parameters of chlorophyll fluorescence analyzing the effect of antibiotics on microalgae.

Gap junctions (GJ) provide metabolic cooperation between cells through the direct exchange of cytoplasmic components. We analyzed the effect of short-term hypoxic stress on the efficiency of communication through the GJs in cultured multipotent mesenchymal stromal cells (MSCs) and characterized the sensitivity of MSCs to short-term hypoxic stress depending on the GJ function. Mitotically inactive MSCs were used in the experiments, in which the GJs were blocked with a specific inhibitor – carbenoxolone. The MSCs were continuously cultured at 20% O2. Further, MSCs with blocked and working GJs were subjected to hypoxic stress (0.1%, 24 hours). The efficiency of GJ communication was attenuated under hypoxic stress. The combined action of GJ inhibition and hypoxic stress was accompanied by an increase in ROS level as compared to the MSCs after hypoxic stress only. MSCs with blocked GJs were less sensitive to short-term hypoxic stress in comparison with MSCs integrated into the common network through working GJs. It was manifested in attenuation of hypoxia-induced angiogenic activity of MSCs. The angiogenic effects of conditioned medium from the MSCs with blocked GJs were almost twice less, which seems to be related to differences in the angiogenic mediators’ profiles: VEGF level decreased and FGF-2 level increased, while the monocyte chemoattractant protein 3 (MCP-3) level was unchanged. Thus, a decrease in the efficiency of direct MSCs- MSCs communication had a negative effect on mostly requested MSCs activity – the ability to induce angiogenesis. We conclude that blocking of GJ communication in MSCs is a negative event that impairs the coordination of MSCs’ response to the microenvironmental factors, in particular hypoxic stress, and reduces their functional plasticity.

Age-related macular degeneration (AMD) is a multifactorial neurodegenerative disease that is becoming the leading cause of irreversible vision loss in people over 55 years of age. The development of the wet form of AMD is associated with impaired permeability of the blood-retinal barrier (BRB). It was believed that the BRB does not change in the dry form of the disease, but recently it was shown that dysfunction of the BRB may also contribute to its development; however, information about the state of the BRB at different stages of AMD, especially preclinical ones, is limited. The purpose of this study was to assess the possible contribution of changes in BRB permeability to the development of signs of AMD in OXYS rats, a model of the dry form of the disease. During the period when clinical signs of AMD in OXYS rats are absent (age 20 days), during their manifestation (~5 months) and progression (at 12 and 18 months), the permeability of the BRB for Evans blue dye and the retinal contents of the tight junction proteins occludin, claudin-5, and zonula occludens-1 (ZO-1) were assessed. Wistar rats of the same age served as controls. In OXYS rats, a decrease in the permeability of the BRB was detected, which may result in a violation of the trophic supply of the retina, as well as an increase in the level of occludin during the progression of signs of AMD. ZO-1 level decreased with age, but no interstrain differences were detected. Analysis of retinal transcriptomes (RNA-seq data) showed that in rats of both strains changes in the expression of genes included (according to KEGG) in the category of tight junctions are maximum in the period from 20 days to 3 months. In OXYS rats, the mRNA levels of the Dlg1, Cd1d1, Map3k5 and Arhgef2 genes at the age of 3 months and the Crb3, F11r, Cgn, Cd1d1 and Rap2c genes the age of 18 months are different compared to Wistar rats. Such changes in gene expression in the retina of OXYS rats as AMD signs develop indicate the activation of compensatory mechanisms.

The history of research into the basic mechanisms of the pathogenesis of Alzheimer’s disease (AD) is briefly considered. Concepts are analyzed in which a decisive role in the development of this disease was attributed to aluminum or free radicals. The lack of reliable data to date to support these concepts is emphasized. The point of view of the author is presented, according to which almost all the results indicating the feasibility of using antioxidants (as well as other potential drugs for AD) for the prevention and treatment of AD were obtained on model animals with certain pathologies (for example, with severe oxidative stress), which contribute to the formation of symptoms similar to those of AD in humans. In this regard, parallels are drawn with experimental gerontological research aimed at studying the effect of a calorie-restricted diet on aging and life span. It is noted that in these studies, animals were used that were either not completely normal or were in unfavorable conditions. According to the author, the lack of significant progress in the development of effective geroprotectors or drugs for the prevention/ treatment of AD is due to the fact that most specialists ignore the principles of classical gerontology, in particular, the definitions of aging and age-related diseases, as well as the correct approaches to the selection of control objects for their studies. It is emphasized that humans, unfortunately, cannot use the freshwater hydra method to combat aging and age-related diseases. Under certain conditions, it continuously renews all cells (including nerve ones) of its body and thereby ensures its “immortality.” In humans, the replacement of “old” neurons can lead to the loss of personality/individuality, and the “repair” of these cells today seems impossible. In this regard, the author considers it expedient to study the aging of postmitotic cells in experiments on stationary cell cultures, which can accelerate, in particular, the deciphering of the mechanisms of accumulation of beta-amyloid and senile pigments such as lipofuscin in neurons. The need for clinical studies of AD is noted as complementary to experimental work, although the first ones are much more expensive and time-consuming. Only confirmation in human studies of the effectiveness of drugs developed in experiments on model animals will allow them to be recommended for use in the clinical practice.