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In this paper we discuss the effect of alkyl glycerol ethers (AGs) from the squid Berryteuthis magister on a chronic stress model in rats. The study was performed on 32 male Wistar rats. Animals received AGs at a dose of 200 mg/kg through a gavage for six weeks (1.5 months), and were divided into four groups: group 1 (control), group 2 (animals received AGs), group 3 (stress control), group 4 (animals received AGs and were subjected to stress). Chronic immobilization stress was induced by placing each rat into an individual plexiglass cages for 2 h daily for 15 days. The serum lipid spectrum was evaluated by the content of total cholesterol, triglycerides, high-density lipoprotein cholesterol, low lipoprotein cholesterol and very low-density lipoprotein cholesterol. The atherogenic coefficient was calculated. The hematological parameters of peripheral blood were evaluated. The neutrophil-lymphocyte ratio was counted. The levels of cortisol and testosterone in blood plasma were determined. AGs at the selected dose did not have a significant effect on the body weight of rats in the preliminary period of the experiment. Under stress, the body weight gain, the concentrations of very low-density lipoprotein cholesterol and blood triglycerides decreased significantly. The neutrophil-lymphocyte ratio in animals treated with AGs shifted towards lymphocytes. A favorable increase in the percentage of lymphocytes was found in the stressed group of animals treated with AGs. So, for the first time, it was found that AGs prevent stress-induced suppression of the immune system. This confirms the benefit of AGs for the immune system under chronic stress. Our results prove the efficiency of the use of AGs for treating chronic stress, a serious social problem in modern society.

Gausemycin A is the first member of the novel lipoglycopeptides family produced by Streptomyces roseoflavus INA-Ac-5812. Gausemycin A has a pronounced bactericidal activity against methicillin-resistant Staphylococcus aureus . However, the ability of S. aureus to be resistant to gausemycin A has not been investigated yet. Using serial passaging, we have obtained the resistant variant S. aureus 5812R, which is 80 times more resistant compared to the parent strain. Susceptibility testing of S. aureus 5812R revealed the acquisition of cross-resistance to daptomycin, cefazolin, tetracycline, and gentamicin, while the resistance to vancomycin, nisin, and ramoplanin was absent. Whole genome sequencing revealed single nucleotide polymorphism (SNP) and deletions in S. aureus 5812R, among which are genes encoding efflux pump ( sepA ), the two-component Kdp system ( kdpE ), and the component of isoprenoid biosynthesis pathway ( hepT) . Phenotypically, S. aureus 5812R resembles a small-colony variant, as it is slow-growing, forms small colonies, and is deficient in pigments. Profiling of fatty acids (FA) composition constituting the cytoplasmic membrane of S. aureus 5812R revealed the prevalence of anteiso -branched FA, while straight FA was slightly less present. The evidence also showed that the gausemycin A-resistant strain has increased expression of the cls2 gene of the cardiolipin synthase. The performed checkerboard assay pointed out that the combination of gausemycin A and ciprofloxacin showed a synergistic effect against S. aureus 5812R., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Poshvina, Dilbaryan, Kasyanov, Sadykova, Lapchinskaya, Rogozhin and Vasilchenko.)

The indicators of spermatogenesis and the state of LPO and antioxidant protection in men with pathozoospermia after COVID-19 were assessed before and after treatment an antioxidant complex. Blood plasma served as the material for biochemical studies. In the examined patients, the parameters of spermatogenesis, as well as blood concentration of LPO components (diene conjugates and TBA-reactive substances) were analyzed. The total antioxidant activity of the blood was determined as an indicator characterizing the total activity of LPO inhibitors and determining its buffer capacity. In patients recovered from COVID-19, an increase in spermatogenesis disorders and shifts towards the predominance of prooxidant factors were observed. After a course (1 month) of antioxidant complex, patients showed increased sperm motility, decreased leukocyte count in the ejaculate, and restored balance in the prooxidant-antioxidant system towards antioxidant components. The effectiveness of correction of post-COVID disorders largely depends on the degree of damage to the structure and function of cell membranes caused by oxidative stress. The use of the antioxidant complex is a promising option, because it reduces the level of LPO, enhances antioxidant protection of the body, and also normalizes some parameters of spermatogenesis., (© 2022. Springer Science+Business Media, LLC, part of Springer Nature.)

The adaptogenic properties of alkylglycerols (AGs) after 1 month's treatment were investigated in a rat model of acute immobilization stress (AIS). The animals receiving AGs 157 mg/kg showed a body weight (BW) decrease in addition to a more pronounced increase in the adrenal glands index under stress conditions. Also, AGs at this dose prevented AIS-induced catalase inhibition. In addition, antiulcerative AG effects were already detected at a dose of 15 mg/kg. The data indicate that AGs promote adrenal gland activation in AIS. At the same time, AGs neutralize some of negative effects of stressful conditions, which include restoration of the oxidation-reduction balance, reduction of gastric mucosal stress lesion formation.LAY SUMMARYThe effect of alkylglycerols, ether lipids from marine organisms, was studied in stressed animals. AGs have antioxidant activity and can be useful in the complex therapy of stomach lesions.

1-O-alkylglycerols (AKG) are a class of natural ether lipids derived from 1-O-alkyl-2,3-diacyl-sn-glycerols by deacylation. In this study, 1-O-alkylglycerol (AKG) composition was investigated in the hepatopancreas lipids of the crab Paralithodes camtschaticus and the liver lipids of the squid Berryteuthis magister and the skate  Bathyraja parmifera. One of the principal AKG in marine organisms was 1-O-hexadecyl-sn-glycerol (AKG 16:0). To assess AKG influence on melanoma, we evaluated the cytotoxicity and antiproliferative actions of natural AKG 16:0 and synthetic 1-O-octyl-sn-glycerol (AKG 8:0) on three human melanoma cell lines SK-Mel-5, SK-Mel-28, and RPMI-7951. Natural AKG 16:0 in concentration up to 20 µM was not toxic to all cell lines. AKG 8:0 showed no toxicity to cells SK-Mel-5 and SK-Mel-28 in concentrations up to 20 µM but had moderate cytotoxicity to RPMI-7951 cells with an IC 50 of 13 µM. Both investigated substances inhibited the proliferation, formation, and growth of cell colonies of RPMI-7951. PRACTICAL APPLICATIONS: AKG exhibit a variety of biological activities, including anticancer effects. In this study, the liver lipids of the skate B. parmifera and the hepatopancreas lipids of crab P. camtschaticus were shown to be sources of AKG. Our data showed that AKG can be used to prevent the formation of new colonies of malignant cells in combination therapy against melanoma. The results will be useful for future studies involving marine ether lipids and the examination of their anticancer properties against malignant cells., (© 2019 Wiley Periodicals, Inc.)

The analgesic activity of docosahexaenoic acid (DHA, 22:6 n-3) was studied using a chronic constriction injury (CCI) rat model. Animals were subcutaneously injected with DHA emulsion at a dose of 4.5mg/kg (125mМ/kg) daily during 2weeks after surgery. We characterized the dynamics of GFAP-positive astrocyte, substance P (SP) and nNOS-positive neurons activity in the spinal cord dorsal horn (SCDH) superficial lamina. We found that DHA treatment decrease the intensity and duration of neurogenic pain syndrome, results in earlier stabilization of weight distribution, prevents the cold allodynia and dystrophic changings in denervated limb tissue. DHA treatment reduced the reactive astrocyte number, decrease SP-immunopositive fibers and nNOS-positive neurons number in the SCDH in neuropathic pain., (Copyright © 2016 Elsevier B.V. All rights reserved.)

The analgetic activity of docosahexaenoic acid (DHA, 22:6 n-3) was studied using a chronic constriction injury (CCI) model in rats, and the dynamics of iba-1 (+) microglia/macrophages in the dorsal root ganglia (DRG) were characterized. DHA reduced the intensity and duration of neurogenic pain. The application of DHA led to an earlier stabilization of weight bearing in the incapacitance test and prevented the development of cold allodynia and degenerative changes in tissues of the denervated limb. DHA treatment significantly reduced satellite glia reaction and expression of the pro-apoptotic p53 protein in the DRG. Thus, DHA's anti-pain effect may be a result of the modulation of microglia/macrophages activity and the development of neuroprotective effects at the level of the dorsal root ganglia., (Copyright © 2015 Elsevier GmbH. All rights reserved.)