High Stress Resistance Research Articles

Metabolomic Analysis of Elymus sibiricus Exposed to UV-B Radiation Stress.

Plants cultivated on the Qinghai-Tibet Plateau (QTP) are exposed to high ultraviolet radiation intensities, so they require effective mechanisms to adapt to these stress conditions. UV-B radiation is an abiotic stress factor that affects plant growth, development, and environmental adaptation. Elymus sibiricus is a common species in the alpine meadows of the QTP, with high-stress resistance, large biomass, and high nutritional value. This species plays an important role in establishing artificial grasslands and improving degraded grasslands. In this study, UV-B radiation-tolerant and UV-B radiation-sensitive E. sibiricus genotypes were subjected to simulated short-term (5 days, 10 days) and long-term (15 days, 20 days) UV-B radiation stress and the metabolite profiles evaluated to explore the mechanism underlying UV-B radiation resistance in E. sibiricus. A total of 699 metabolites were identified, including 11 primary metabolites such as lipids and lipid-like molecules, phenylpropanoids and polyketides, organic acids and their derivatives, and organic oxygen compounds. Principal component analysis distinctly clustered the samples according to the cultivar, indicating that the two genotypes exhibit distinct response mechanisms to UV-B radiation stress. The results showed that 14 metabolites, including linoleic acid, LPC 18:2, xanthosine, and 23 metabolites, including 2-one heptamethoxyflavone, glycyrrhizin, and caffeic acid were differentially expressed under short-term and long-term UV-B radiation stress, respectively. Therefore, these compounds are potential biomarkers for evaluating E. sibiricus response to UV-B radiation stress. Allantoin specific and consistent expression was up-regulated in the UV-B radiation-tolerant genotype, thereby it can be used to identify varieties resistant to UV-B radiation. Different metabolic profiles and UV-B radiation response mechanisms were observed between the UV-B radiation-tolerant and UV-B radiation-sensitive E. sibiricus genotypes. A model for the metabolic pathways and metabolic profiles was constructed for the two genotypes. This metabolomic study on the E. sibiricus response to UV-B radiation stress provides a reference for the breeding of new UV-B radiation-tolerant E. sibiricus cultivars.

Myocardial contractile function in the post-traumatic period of cardiac contusion in rats with different stress resistance: A preclinical experimental randomized trial

Background. Pathogenesis of cardiac contusion involves primary traumatic and secondary hypoxic mechanisms of myocardial contractile function depression as well as body reactions aimed at adapting to altered environment. A significant part of these reactions is realized in the context of stress. The intensity of the stress component in myocardial dysfunction is largely determined by the individual stress reactivity of the body. Objectives. To assess the contractile function and functional reserves of the myocardium of rats with a high and low level of stress resistance in the post-traumatic period of cardiac contusion. Methods. A preclinical experimental randomized trial involved 134 white mature nonlinear male rats weighing about 270 g. The animals were divided by sequentially performed Open Field and Porsolt Forced Swim tests into 2 groups: group 1 — animals with low stress resistance, group 2 — animals with high stress resistance. Within each group, the animals were randomized into control and experimental subgroups. In the experimental subgroups, 6, 12 and 24 hours after simulating cardiac contusion, the force and rate indicators of myocardial contractility were evaluated using the Fallen isolated heart model. The summary measures of the study included assessing the contractile force and rate of isolated hearts of rats with low and high stress resistance, particularly under conditions of high-frequency rhythm load (ranging from 4.0 to 8.3 Hz) during the post-traumatic period of cardiac contusion. Data analysis was performed using software packages MS Office 2013 (Microsoft Corporation, USA) and Statistica, v. 10 (StatSoft, USA). The differences were considered to be statistically significant at p < 0.05. Results. 6, 12 and 24 hours after simulating a cardiac contusion, contractile force and rate of isolated hearts decreased in group 1 and group 2. In low stress-resistant animals, immediately following the stabilization period and during high-frequency rhythm test, the contractility force and rate in isolated hearts were statistically significantly lower (p = 0.0008) compared to those recorded in highly stress-resistant individuals. During the stimulation of a high-frequency rhythm, isolated hearts in the experimental group revealed diastolic dysfunction at all time points. In highly stress-resistant animals, diastolic dysfunction occurred at a heart rate of 300 min-1 and above, whereas in low stress-resistant animals, it manifested at a heart rate of 240 min-1 and above. At the same heart rate, diastolic dysfunction in low stress-resistant animals was statistically significantly greater (p = 0.0008) compared to that of highly resistant animals. Conclusion. The post-traumatic period following experimental myocardial contusion is characterized by a reduction in the force and rate of myocardial contractility, as well as a decrease in functional reserves of the myocardium, regardless of stress resistance. High stress resistance is associated with better preservation of cardiac contractile function and contractility reserves, whereas low stress resistance correlates with a more pronounced degree of myocardial dysfunction and a significant reduction in functional reserves of the contused heart. Differences in the severity of contractile dysfunction under conditions of high and low body resistance to stress can be attributed to varying degrees of secondary myocardial damage in the contused area, resulting from the misbalance between stress-activating and stress-limiting mechanisms involved in the development of secondary damage.

The thylakoid phosphatase TEF8 is involved in state transition and high light stress resistance in Chlamydomonas.

The sophisticated regulation of state transition is required to maintain optimal photosynthetic performance under fluctuating light condition, through balancing the absorbed light energy between photosystem II andphotosystem I. This exquisite process incorporates phosphorylation and dephosphorylation of light-harvesting complexes and PSII core subunits, accomplished by thylakoid membrane-localized kinases and phosphatases that have not been fully identified. In this study, one Chlamydomonas high light response gene, THYLAKOID ENRICHED FRACTION 8 (TEF8), was characterized. The Chlamydomonas tef8 mutant showed high light sensitivity and defective state transition. The enzymatic activity assays showed that TEF8 is a bona fide phosphatase localized in thylakoid membranes. Biochemical assays, including BN-PAGE, pull-down, and phosphopeptide mass spectrometry, proved that TEF8 associates with photosystem II and is involved in the dephosphorylation of D2 and CP29 subunits during state 2 to state 1 transition. Taken together, our results identified TEF8 as a thylakoid phosphatase with multiple dephosphorylation targets on photosystem II, and provide new insight into the regulatory mechanism of state transition and high light resistance in Chlamydomonas.

Functional analysis of LdPMAT1, a positive regulator that promotes drought tolerance in Lilium distic hum nakai

Abiotic stress has become a major challenge for lily crop growth, development, yield and quality under irregular climate and precipitation trends. Molecular breeding is one of the most effective methods for developing highly stress-resistant cultivars. Previous studies revealed that miR396b and its target gene LdPMAT1 are involved in drought resistance, and in lily silencing miR396b significantly enhances drought resistance and LdPMAT1 expression. However, the function of LdPMAT1 in the lily response to abiotic stress is unclear. In this study, GUS activity tests and dual luciferase reporter gene assays (LUC) confirmed that LdPMAT1 is a novel miR396b target. The LdPMAT1 transcription level was greater in the roots and leaves and increased significantly within 7 days of drought stress. Stable LdPMAT1 overexpression significantly reduced leaf wilting and enhanced cell membrane stability by affecting osmoregulatory substance accumulation, improving plant drought resistance. Additionally, LdPMAT1 overexpression significantly increased the expression levels of LdCAT3 and SOD2, which encode superoxide dismutase (SOD) and catalase (CAT), respectively, as well as SOD and CAT enzyme activities. In contrast, reactive oxygen species (ROS) accumulated at high levels in the leaves and roots of the silenced plants, and the degree of damage was significantly greater than that in the wild type plants. Under conditions of 1% NaCl and 42 °C, plants overexpressing LdPMAT1 exhibited similar characteristic s of high stress resistance, with less wilting and lower ROS accumulation. This study provides a theoretical basis for cultivating new highly resistant lily cultivars and accelerating germplasm innovation to produce high-quality lilies worldwide.

Ecological plasticity of soft winter wheat varieties and resistance to snow mould pathogen (Microdochium nivale (Fr.) Samuels & I.C. Hallett)

Identifying superior genotypes of soft winter wheat with high ecological plasticity to soil and climatic conditions, combined with tolerance to common diseases caused by fungal pathogens, including snow mould, is becoming increasingly important for both production and breeding. This is driven by the global demand for environmentally safe products. The preliminary selection of the most valuable initial material with high-stress resistance to periodic climate changes and deteriorating phytosanitary conditions is essential for the success of the breeding process in addressing current challenges. This study aimed to determine the level of ecological plasticity in soft winter wheat varieties, differentiated by their resistance to the snow mould pathogen, through the analysis of genotype effect ranks and yield regression coefficients. Additionally, high-yielding sources were identified for use in breeding for adaptability. The research was conducted according to commonly accepted methodologies for evaluating materials based on disease resistance and adaptive traits, ensuring a highly objective interpretation of the results obtained. It was determined that the highest ecological plasticity among the studied material was differentiated by resistance to Microdochium nivale (Fr.) Samuels & I.C. Hallett, was exhibited by five varieties (16.7%) that achieved yields ranging from 118% to 129% of the standard. These include the varieties Muza Bilotserkivska, Askaniiska Berehynia, Hetmanska, Malovanka (UKR), and Nordika (CZE), as evidenced by the lowest sum of ranks (sum of ranks 2) for the genotypic effect (εi ) and regression coefficient (Ri ). New sources of high and stable resistance in soft winter wheat to the snow mould pathogen were identified, specifically: Sanzhara, Malovanka, Svitiaz, Muza Bilotserkivska (UKR); Smuga (POL), and Nordika (CZE). It was found that, in soft winter wheat varieties, resistance to Microdochium nivale (Fr.) Samuels & I.C. Hallett significantly negatively correlates with the sum of ranks for genotypic effect and yield plasticity, with r =-0.69, P < 0.01. The systematisation of the results obtained and the identification of varieties with the highest ecological plasticity under variable weather conditions within the agroecological zone allows for the identification of the best gene pool for adaptive breeding

Assessment of adaptive properties of winter triticale cultivars by yield in the Middle Urals

Triticale is a versatile crop with high yield potential but insufficient resistance to unfavourable growing conditions. Therefore, the combination of high yield, adaptability, plasticity, stability and stress resistance of varieties is of great importance. The purpose of the research is to assess the adaptive potential of winter triticale cultivars according to the "yield" trait in agroecological conditions of the Middle Urals. Field studies were conducted in the Udmurt Republic in the years with contrasting weather conditions (2021–2023), the index of environmental conditions varied from -128 to 152. Forty-five cultivars of various ecological and geographical origin were studied. The analysis of the adaptive potential of the cultivars was carried out using various statistical methods. As a result, the most adaptive cultivars for the agroecological conditions of the Middle Urals were identified. The cultivars ‘Beta’, ‘Tribune’, ‘Topaz’, ‘Linda’ (Russia), ‘Mayak’, ‘Ales’ (Belarus), ‘Torchinsky’ (Ukraine) were char- acterized by high responsiveness to improving environmental conditions (bi = 1.82 2.01). The cultivars ‘Giray’, ‘Bereket’, ‘Ataman Platov’ (Russia), ‘Amulet’ (Belarus) showed relatively high stress resistance. The cultivars ‘Beta’, ‘Zimogor’, AD 1405, ‘Topaz’, ‘Kornet’ (Russia) were distinguished by a high compensatory ability. The cultivars ‘Bereket’ and ‘Ataman Platov’ had the lowest yield variability and at the same time high homeostaticity. When ranking the tested cultivars according to the listed indicators, the top ten most stable and plastic cultivars were ‘Zimogor’, ‘Kornet’, ‘Ataman Platov’, ‘Bereket’, ‘Nemchinovsky 56’, ‘Izhevskaya 2’, ‘Imprint’, ‘Bard’ (Russia), ‘Impulse’ (Belarus), ‘Chernobrivets’ (Ukraine), with a total ranking score from 55 to 95 points. The listed cultivars can be classified as the most valuable. In the agroecological conditions of the Middle Urals, it is advisable to cultivate varieties that combine high yields and adaptability – ‘Zimogor’, ‘Kornet’, ‘Izhevskaya 2’, and according to intensive technology – ‘Beta’ cultivar. The cultivars ‘Ataman Platov’, ‘Chernobrivets’, ‘Bereket’, ‘Bard’, ‘Impulse’, ‘Nemchinovsky 56’ also have practical value as a source material in the breeding of winter triticale to increase productivity and adaptability. A comparison of different methods for determining the adaptability of cultivars to specific environmental conditions showed the practical equivalence of the indicators of yield range, yield variation coefficient and homeostaticity.

The ubiquitin-proteasome system regulates the formation of specialized ribosomes during high salt stress in yeast.

Rps26-deficient ribosomes are a physiologically relevant ribosome population which arises during osmotic stress to support the translation of mRNAs involved in the response to high salt in yeast. They are formed by binding of the chaperone Tsr2 to fully assembled ribosomes to release Rps26 when intracellular Na+ concentrations rise. Tsr2-mediated Rps26 release is reversible, enabling a rapid response that conserves ribosomes. However, because the concentration of Tsr2 relative to ribosomes is low, how the released Rps26•Tsr2 complex is managed to allow for accumulation of Rps26-deficient ribosomes to nearly 50% of all ribosomes remains unclear. Here we show that released Rps26 is degraded via the Pro/N-degron pathway, enabling the accumulation of Rps26-deficient ribosomes. Substitution of the N-terminal proline of Rps26 to serine increases the stability of free Rps26, limits the accumulation of Rps26-deficient ribosomes and renders yeast sensitive to high salt. The GID-complex, an E3 ubiquitin ligase, and its adaptor Gid4, mediate polyubiquitination of Rps26 at Lys66 and Lys70. Moreover, this ubiquitination event is required for Rps26 degradation, the accumulation of Rps26-deficient ribosomes and the high salt stress resistance. Together, the data show that targeted degradation of released Rps26 from the Rps26•Tsr2 complex allows Tsr2 to be recycled, thus facilitating multiple rounds of Rps26 release.

Riverbank fascines mostly fail due to scouring: Consistent evidence from field and flume observations

AbstractThe willow fascine soil bioengineering technique is commonly used worldwide in river restoration projects to stabilize riverbanks, thanks to high theoretical shear stress resistance and adaptable configuration. Fascines are composed of bundles of living branches fixed between stakes. When positioned in meanders at bank toe, they are subjected to strong hydraulic constraints. Here, we present the field back‐analysis of 470 willow fascines alongside experiments in a small‐scale model (scale 1:25). We describe the dynamics of failure in various situations. The field analysis revealed that 78% of fascines present no signs of bank instability. No fascines were pulled out, and they rarely showed signs of destruction once vegetation had established. Flume experiments confirmed that the main mechanical process of failure is erosion at fascine toe and extremities (9% and 3% of occurrence in the field, respectively). The dynamics of failure occur through: (i) erosion at the fascine toe, removing materials under the bundle; (ii) bank sediments, sliding underneath the fascine; (iii) scouring, leaving stakes exposed to falling into the river. Based on these observations, the fascine toe should be protected sufficiently deeply against undermining to keep sediments in place while vegetation is established. Bank slopes should be reduced as far as possible to decrease scouring. Finally, the mean shear stress values used as reference when designing bioengineering techniques do not capture the local and continuous scouring processes leading to failure. Thus, bend curvature, degradation, grain sizes, and level of fascine implementation should be considered when adapting design.

Comparative Effects of Water Scarcity on the Growth and Development of Two Common Bean (Phaseolus vulgaris L.) Genotypes with Different Geographic Origin (Mesoamerica/Andean).

Drought stress is widely recognized as a highly detrimental abiotic stress factor that significantly impacts crop growth, development, and agricultural productivity. In response to external stimuli, plants activate various mechanisms to enhance their resistance or tolerance to abiotic stress. The common bean, a most important legume according to the FAO, serves as a staple food for millions of people worldwide, due to its rich protein, carbohydrate, and fiber content, concurrently, and water scarcity is the main factor limiting common bean production. The process of domestication and on-farm conservation has facilitated the development of genotypes with varying degrees of drought stress resistance. Consequently, using landraces as biological material in research can lead to the identification of variants with superior resistance qualities to abiotic stress factors, which can be effectively integrated into breeding programs. The central scope of this research was to find out if different geographic origins of common bean genotypes can determine distinct responses at various levels. Hence, several analyses were carried out to investigate responses to water scarcity in three common bean genotypes, M-2087 (from the Mesoamerican gene pool), A-1988 (from the Andean gene pool) and Lechinta, known for its high drought stress resistance. Plants were subjected to different water regimes, followed by optical assessment of the anatomical structure of the hypocotyl and epicotyl in each group; furthermore, the morphological, physiological, and biochemical parameters and molecular data (quantification of the relative expression of the thirteen genes) were assessed. The three experimental variants displayed distinct responses when subjected to 12 days of water stress. In general, the Lechinta genotype demonstrated the highest adaptability and drought resistance. The M-2087 landrace, originating from the Mesoamerican geographic basin, showed a lower resistance to water stress, compared to the A-1988 landrace, from the Andean basin. The achieved results can be used to scale up future research about the drought resistance of plants, analyzing more common bean landraces with distinct geographic origins (Mesoamerican/Andean), which can then be used in breeding programs.

ИСТОЧНИКИ КРУПНОЯГОДНОСТИ СОРТОВ ВИНОГРАДА АНАПСКОЙ АМПЕЛОГРАФИЧЕСКОЙ КОЛЛЕКЦИИ

The aim of the study is to examine grape varieties in the collection of the Anapa Experimental Station in order to identify genetic sources of large-berry fruit. Varieties that are donors or sources of economically valuable traits, such as high productivity, large-berry fruit, stress resistance, adaptability, and taste, are found among representatives of the eco-geographical groups of European-Asian grapes. This work is relevant because it is the foundation for the selection process of grape culture and the production of new zoned large-berry varieties that are in great demand on the market and necessary in times of import substitution. Currently, the collection consists of many varieties of different eco-geographical origins, table and technical uses. The gene pool of grapes is replenished every year. These varieties are used annually in breeding to develop new high-quality grape varieties. The objects of research were the source varieties of large-berry grapes from different geographical zones. In this research work, modern programs and me-thods were used along with traditional breeding methods. The paper presents four sources of large-berry grapes, gives their brief characteristics, shows the dynamics of the main phenological and agrobiological indicators for 2021–2023. Among the source varieties, the following varieties stand out in terms of the frui-ting coefficient: Brigantina (K1 – 1.0–1.2) and Muromets (K1 – 1.0–1.1), and in terms of yield per bush – Pobeditel, Brigantina and Yubiley Moldavii. These varieties are used in experimental work on varietal directed crossing of supposed carriers of economically valuable selection traits and further obtaining seeds of new hybrid offspring.

Individual and psychological characteristics of medical university students with different stress resistance

The individual and psychological characteristics of 181 students with different levels of stress resistance were studied. Was revealed the dominance of the mechanisms of regression (8.77 ± 2.40 points), projection (7.03 ± 2.04 points) and rationalization (6.73 ± 1.89 points) with a lower intensity of compensation mechanisms (5.45 ± 1.68 points), denial (4.80 ± 1.71 points) and displacement (4.80 ± 2.02 points), and minimal expression of mechanisms of hypercompensation (4.42 ± 1.67 points) and substitution (4.38 ± 2.07 points). The mechanism of rationalization is more intense in students with high stress resistance, the mechanisms of regression, projection, compensation and hypercompensation — in students with moderate stress resistance, and displacement, substitution and denial — in students with weak stress resistance. The average level of resilience was found in the examinees: 25.25 ± 10.62 points, while in students with high stress resistance, the indicator corresponded to a higher than average level: 29.22 ± 6.70 points, in students with moderate stress resistance — to an average level: 24.31 ± 11.21 points, and in students with weak stress resistance — a lower than average level: 16.28 ± 12.43 points. The resilience index is inversely correlated with the stress resistance index (rS = –0.352, p = 0.001), which indicates that higher stress resistance is associated with greater resilience. The state of hardiness of medical students as a whole and of students with high and moderate stress resistance corresponds to a high level: respectively 20.10 ± 7.48 points, 23.59 ± 6.39 points and 19.37 ± 6.41 points, and in students with weak stress resistance — moderate level: 12.03 ± 6.00 points. All components of hardiness — commitment, control and challenge are most pronounced in students with high stress resistance, and least pronounced — in students with weak stress resistance. The stress resistance indicator is inversely correlated with hardiness (rS = –0.519, p = 0.000), commitment (rS = –0.464, p = 0.000), control (rS = –0.477, p = 0.000) and challenge (rS = –0.461, p = 0.000), which indicates that higher stress resistance is associated with greater hardiness. Key words: medical university students, stress resistance, psychological protection, hardiness, resilience

Formation of iron-rich encrustation layer on anammox granules for high load stress resistance: Performance, advantages, and mechanisms

Anaerobic ammonia oxidation (anammox) is a cost-effective technology but its performance can be seriously inhibited by high load stress. This study has created an innovative iron-rich encrustation layer (IEL) on the surface of anammox granules (AnGS) through the addition of a certain amount of nano zero-valent iron. The IEL was formed through the aggregation of a gel network and the binding of iron species with extracellular polymeric substances (EPS), resulting in a significant increase in settling ability, EPS secretion, and heme content. Metagenomic analysis indicated a notable rise in the functional genes associated with nitrogen andiron metabolism in IEL AnGS. Under high load stress, the ammonia removal performance of AnGS without IEL severely declined. In contrast, IEL AnGS exhibited excellent ammonia removal efficiency of over 90%. The IEL served as a protective barrier for AnGS, effectively mitigating the strong shear forces, thereby enhancing their resistance to high load stress.

Expression of Beclin-1 and Caspase-3 After the Myocardial Contusion in Rats With High and Low Stress Resistance

Aim. To evaluate the activity of autophagy and apoptosis in the myocardium of rats with differentstress resistance after the modeling of myocardial contusion.Materials and Methods. The study was performed on 106 white male rats weighing 250-300 g. The rats were ranked according to stress tolerance, and medium-resistant individuals (n = 42) were excluded from the experiment. Control (n = 16) and experimental (n = 48) groups were formed from the remaining animals; the control group included subgroups with high and low stress resistance, and the experimental group included 6 subgroups (rats with high and low stress resistance; 6, 12, and 24-hour time points). Each of the subgroups included 8 animals. Myocardial contusion was modeled in the experimental group. At 6-, 12- and 24-hour time point, rat hearts have been excised and 5×5 mm myocardial fragments were dissected from the areas with the most prominent traumatic effects (interventricular septum, anterior walls of the left and right ventricles). Tissues were then sectioned and stained with antibodies to Beclin-1 and caspase-3.Results. We have documented a significant expression of Beclin-1 and Caspase 3 expression in rat hearts after myocardial contusion. From 6 to 24 hours upon the myocardial contusion, Beclin-1 expression has been increased in rats with high stress resistance but was reduced in rats with low stress resistance. Expression of caspase-3 expression was registered exclusively at 24-hour time point in rats with high stress resistant but increased along the time points in rats with low stress resistance.Conclusion. Expression of Beclin-1 and caspase-3 in rat myocardium indicated autophagy and apoptosis upon the myocardial contusion. Temporal patterns of Beclin-1 and caspase-3 expression were opposite in rats with high and low stress resistance.

Estimation of adaptability parameters of collection hulled oats varieties according to productivity in the Kirov region

The current paper has presented the study results conducted on the experimental plot of the Falenskaya breeding station of the branch of the FSBI FANC of the North-East in 2021–2023. The purpose of the study was to evaluate the collection hulled oat varieties according to grain productivity and adaptability parameters in the soil and climatic conditions of the Kirov region. The materials for the study were 9 collection oat varieties and the standard variety ‘Krechet’. According to the trait ‘productivity’, there have been estimated adaptability parameters. During the testing years, the studied variety samples differed significantly in productivity variability (V = 16.8–30.0 %). The factor ‘year’ had the greatest effect on the formation of oat yields (90.3 %). In the arid year of 2021, the varieties’ productivity was low (276–401 g/m2), with a negative index of environmental conditions (Ij = -163), in the most favorable year of 2022, it was 463–682 g/m2 and Ij = 104, respectively. The variety samples ‘k-3967 0144’ (-190 g/m2) and ‘15584 Mutant 258’ (-214 g/m2) were characterized by high stress resistance. High genetic flexibility of mean productivity under contrasting conditions was established in the variety samples ‘15472 Sumphony’ (504 g/m2), ‘k-3967 0144’ (496 g/m2) and ‘15340 Uran’ (487 g/m2). There have been identified such gene sources as plastic ‘k-3967 0144’, ‘15472 Sumphony’, ‘15340 Uran’, ‘k-3951 0146’, ‘k-3954 0149’ (IEP = 1.13–1.0), and with high stability of the trait ‘productivity’ ‘k-3967 0144’, ‘15584 Mutant 258’, ‘k-3954 0149’ (SF = 1.47–1.78). Low variability and high homeostaticity were found in the variety samples ‘k-3967 0144’, ‘15584 Mutant 258’, ‘k-3954 0149’ (V = 16.8–22.8 %; Hom = 31.31–20.75) with a high stability index (Is = 5.95–4.38). The adaptability coefficient has confirmed the high adaptability of variety samples ‘k-3967 0144’, ‘15472 Sumphony’ and ‘15340 Uran’ (KA =112.3–108 %). In adaptive breeding for further work, the varieties ‘k-3967 0144’, ‘15584 Mutant 258’, ‘k-3954 0149’, ‘15472 Sumphony’, ‘15340 Uran’ are of great interest, since they are the most adaptive in terms of the sum of ranks. Based on a comprehensive estimation of productivity and adaptability parameters, ‘k-3967 0144’ was recognized as the best variety sample, which can give a large mean productivity (526 g/m2) in changing weather conditions.

Ribosomal mutations enable a switch between high fitness and high stress resistance in Listeria monocytogenes.

Multiple stress resistant variants of Listeria monocytogenes with mutations in rpsU encoding ribosomal protein RpsU have previously been isolated after a single exposure to acid stress. These variants, including L. monocytogenes LO28 variant V14 with a complete deletion of the rpsU gene, showed upregulation of the general stress sigma factor Sigma B-mediated stress resistance genes and had a lower maximum specific growth rate than the LO28 WT, signifying a trade-off between stress resistance and fitness. In the current work V14 has been subjected to an experimental evolution regime, selecting for higher fitness in two parallel evolving cultures. This resulted in two evolved variants with WT-like fitness: 14EV1 and 14EV2. Comparative analysis of growth performance, acid and heat stress resistance, in combination with proteomics and RNA-sequencing, indicated that in both lines reversion to WT-like fitness also resulted in WT-like stress sensitivity, due to lack of Sigma B-activated stress defense. Notably, genotyping of 14EV1 and 14EV2 provided evidence for unique point-mutations in the ribosomal rpsB gene causing amino acid substitutions at the same position in RpsB, resulting in RpsB22Arg-His and RpsB22Arg-Ser, respectively. Combined with data obtained with constructed RpsB22Arg-His and RpsB22Arg-Ser mutants in the V14 background, we provide evidence that loss of function of RpsU resulting in the multiple stress resistant and reduced fitness phenotype, can be reversed by single point mutations in rpsB leading to arginine substitutions in RpsB at position 22 into histidine or serine, resulting in a WT-like high fitness and low stress resistance phenotype. This demonstrates the impact of genetic changes in L. monocytogenes' ribosomes on fitness and stress resistance.

Psychological features of HIV-infected patients depending on the stage of the disease

The relevance of the problem. Currently, the issue of HIV infection is acute all over the world, and the variety of HIV clinical forms is striking in its vastness and congruence with other pathologies. Among Russian and foreign publications devoted to psychological changes in patients with HIV infection, there is a lack of works on the relationship of their levels of resistance to the action of stress agents, the effectiveness of the formation of protective and compensatory behavior with differentiation by spheres (cognitive, emotional, and behavioral), and the absence or presence of alexithymia of varying degrees of severity in their personal psychological type with self-assessment of wellbeing, the severity of infection, and the presence of complications. The purpose of the study: to identify and compare the psychological characteristics of the personality of HIV-infected patients, depending on the stage of the disease. Materials and methods. We observed 150 male and female volunteers (83 and 67 patients, respectively), whose mean age was 37.5 (33.9; 42.1) years, living in the city of Saratov and the Saratov region. The patients were divided into three groups depending on the stage of the disease: Group I — the patients with HIV infection in the incubation stage (Stage 1 — incubation), Group II — the patients with steadily progressing HIV infection (Stage 2 — stage of primary manifestations and Stage 3 — subclinical); Group III — the patients with continuing HIV replication, accompanied by the death of CD4+ lymphocytes and the depletion of their population to zero (Stage 4 — stage of secondary diseases and Stage 5 — terminal). The patients were followed up at the public health institution Saratov Regional Clinical Center for AIDS Prevention and Control. Results. The following patterns, confirmed statistically, were revealed: the lower the resistance of the patients to the action of stress agents was, the higher their anxiety was and significantly more often both the tendency to alexithymia and its obvious clinical signs were revealed. Thus, it is advisable for all patients, regardless of the stage of progression of HIV infection, to determine the levels of stress resistance, since with a decrease in this indicator, their level of anxiety increases, a tendency to alexithymia appears, and sleep disturbances, mood disorders, memory impairment, and decreased performance occur, in contrast to patients with high stress resistance.

Optimizing mycelial protein yield in Pleurotus djamor via ARTP mutagenesis and hybridization strategies

With the world’s population rapidly increasing, the demand for high-quality protein is on the rise. Edible fungi breeding technology stands as a crucial avenue to obtain strains with high yield, high-quality protein, and robust stress resistance. To address the protein supply gap, Atmospheric and Room Temperature Plasma (ARTP) mutagenesis, and spore hybridization techniques were employed to enhance Pleurotus djamor mycelium protein production. Beginning with the original strain Pleurotus djamor JD-1, ARTP was utilized to mutate spore suspension. The optimal treatment time for Pleurotus djamor spores, determined to achieve optimal mortality, was 240 s. Through primary and secondary screenings, 6 mutant strains out of 39 were selected, exhibiting improved protein yield and growth rates compared to the original strain. Among these mutagenic strains, 240S–4 showcased the highest performance, with a mycelial growth rate of 9.5±0.71 mm/d, a biomass of 21.45±0.54 g/L, a protein content of 28.75±0.92%, and a remarkable protein promotion rate of 128.03±7.29%. Additionally, employing spore hybridization and breeding, 7 single-nuclei strains were selected for pin-two hybridization, resulting in 21 hybrid strains. The biomass and protein content of 9 hybrid strains surpassed those of the original strains. One hybrid strain, H-5, exhibited remarkable mycelial protein production, boasting a mycelial growth rate of 26.5±0.7 mm/d, a biomass of 21.70±0.46 g/L, a protein content of 28.44±0.22%, and a protein promotion rate of 128.02±1.73%. Notably, both strains demonstrated about a 28% higher mycelial protein yield than the original strains, indicating comparable effectiveness between hybrid breeding and mutagenesis breeding. Finally, we analyzed the original and selected strains by molecular biological identification, which further proved the effectiveness of the breeding method. These findings present novel insights and serve as a reference for enhancing edible fungi breeding, offering promising avenues to meet the escalating protein demand.

Physiological and Biochemical Responses of Melilotus albus to Saline and Alkaline Stresses

Sweet clover (Melilotus albus) is a high-quality leguminous forage grass with salinity tolerance, drought tolerance, and cold hardiness. We selected four varieties of sweet clover with different sensitivities (061898, 061930, No. 55 white flower, and Ningxia white flower) and analyzed the effects of different concentrations of three sodium salts (Na2CO3, NaHCO3, and NaCl) on their physiology and biochemistry responses. Growth and development indexes (such as germination rate, root length, shoot length), chlorophyll content, osmotic regulators (proline, soluble sugar), malondialdehyde (MDA), superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) were determined under saline–alkali stress. Seed germination and seedling growth of all four clover species were significantly inhibited under saline–alkali stress. During germination, seed germination rate, root length, and shoot length decreased with increasing saline and alkaline concentration. Under saline–alkali stress, chlorophyll content tended to increase and then decrease, cell damage and death increased, and malondialdehyde, soluble sugar, and proline content tended to increase and then decrease. Moreover, the activities of SOD, POD, and CAT all increased and then decreased. Under Na2CO3 stress, the decrease in chlorophyll content of the resistant variety 061898 was less than in the sensitive Ningxia white flower variety. As the concentrations of Na2CO3, NaHCO3, and NaCl increased, the maximum photochemical efficiency of PSII was significantly affected. The resistant 061898 is capable of maintaining higher photosynthetic efficiency. Furthermore, under treatments with the three kinds of saline–alkali solutions, cell damage and death for Ningxia white flower were greater than in 061898. For 061898, the increases in soluble sugar and proline content were greater and the increase in malondialdehyde content was less, while the antioxidant enzyme activities were higher than those in Ningxia white flower. All four sweet clover varieties had higher stress resistance with neutral than with alkaline salts. When stressed by medium to high saline–alkali concentrations, sweet clover seedlings had increased osmotic substance content, enhanced antioxidant enzyme activity, and regulated physiological metabolism. Additionally, sweet clovers regulated the expression of WRKY33, GH3, CYCD3, OXI1, MKK2, MYC2, JAZ, COI1, PYL, PP2C, TGA, and MPK3 to adapt to the saline–alkali environment and improve saline–alkali tolerance. Our analysis of the sweet clover salinity tolerance mechanism contributes to its further use and is of significant importance for addressing land salinization and promoting sustainable agricultural and pastoral practices in China.

Study results of the parameters of winter barley adaptability according to forecrops

The development and wide distribution of new adaptive varieties in production is a promising and environmentally friendly way for the development of agriculture. A new, more modern, highly productive variety can ensure increased productivity, resistance of crops to stress factors, and promotes better use of natural and anthropogenic resources. The leading direction in breeding in the nearest future should be not the development of varieties in general, adapted to growing conditions, but the identification of varieties adapted to the stress-limiting environmental factors of a particular region, adaptive to the challenges of nature. In addition to the characteristics of the variety and environmental conditions, the forecrop also influences its productivity. Selection in some conditions may not reveal the potential of the genotype in others, which makes it important to obtain information on different growing environments of varieties at the early stages of breeding. The purpose of the current study was to determine the adaptive properties of promising winter barley varieties and lines according to various forecrops. The study was carried out from 2021 to 2023 to estimate the adaptability parameters of 20 winter barley varieties and lines developed by the FSBSI Agricultural Research Center “Donskoy” for various forecrops (weedfree fallow, peas, sunflower, winter wheat). To determine the indicators of homeostaticity (Hom) and selection value (Sc), stress resistance (Ymin–Ymax) and genetic flexibility ((Ymax+Ymin)/2), the coefficient of responsiveness to favorable growing conditions (Kr) and the indicator of the stability level of the variety (VSLI), there have been applied the methods of V.V. Khangildin and N.A. Litvinenko (1981), A.A. Rosielle and J. Hamblina as presented by A.A. Goncharenko (2005), V.A. Zykin (2005), E.D. Nettevich (2001). According to all forecrops, there have been identified the varieties distinguished by high parameters of environmental adaptability and stability. Stress-resistant genotypes included the lines ‘Parallelum 2016’ and ‘Parallelum 2017’ (Ymin–Ymax = 1.2, 1.1, respectively), which were distinguished by a set of stability indicators and have been recommended for use in the breeding process as sources of high stress resistance, low yield variability, capable of minimizing negative impact of growing conditions. The variety ‘Step’ proved to be adaptable (regression coefficient bi = 1.5), genetically flexible ((Ymin–Ymax)/2 = 7.7), and highly responsive to growing conditions (Kr = 1.53). The dynamics of productivity corresponded to changes in growing conditions, and to maximize a productivity level, there has been recommended to cultivate it on intensive forecrops.

Tribological behaviour of TiAlN and AlCrN coatings on stainless steel

TiAlN and AlCrN coatings are widely used in applications that require high stress resistance. In this work, the tribological behaviour of physical vapour deposition (PVD) TiAlN and AlCrN commercial coatings deposited on AISI martensitic stainless steel is studied. Microstructure of the coatings was analysed by X-ray diffraction (XRD), optical microscopy (OM) and scanning electron microscopy (SEM) and nanohardness was measured. Pin-on-disk and abrasive wear tests were performed. Adhesion was evaluated using Rockwell C Indentation and scratch test. The thickness of both coatings was approximately 3 µm. AlCrN lost 30 and 10 times less volume than TiAlN in pin-on-disk tests, under low and high loads, respectively. The steady friction coefficient value was also lower. This indicated that the AlCrN coating had a better performance under sliding conditions. On the other hand, the mass loss was similar for both coatings under abrasive wear, even under severe conditions. In the scratch tests, TiAlN coating failed at 60 N load and AlCrN coating at 70 N, the latter showing a higher value of critical load. The deformation was similar for both coatings as it could be observed in the profiles obtained by a mechanical profilometer at 60 N, however, AlCrN did not show film delamination. This enhanced performance can be attributed to higher fracture toughness and load carrying capacity, which not only improved the mechanical properties of the coating but also its adhesion to the stainless-steel substrate.