Stresses, Volume 4, Issue 2 (June 2024) – 15 articles

The increasing demands for food, driven by shrinking arable land areas and a growing population, underscore the need for innovative agricultural practices to mitigate the effects of soil degradation due to salinity and promote food security, particularly in regions heavily impacted by salinity. In this study, we investigated the effects of inoculating the arbuscular mycorrhizal fungus (AMF) Rhizophagus clarus on the productivity of Vigna unguiculata cv. BRS Imponente plants in response to salinity (0, 25, 50, 75, and 100 mM). We found that NaCl concentrations ≥ 50 mM were phytotoxic, reducing plant growth and productivity. However, inoculation with AMF reduced plant oxidative stress (hydrogen peroxide concentration and lipid peroxidation) and ionic stress (Na⁺/K⁺ ratio). Inoculated plants exhibited increased antioxidant enzyme activity (ascorbate peroxidase and catalase), higher P and K concentrations, and lower Na concentrations in their leaves. As a result, salt did not interfere with grain production in the AMF-inoculated plants. For the first time, we demonstrate that inoculation with R. clarus can counteract the harmful effects of NaCl in V. unguiculata plants, ensuring their grain yields. Therefore, amid the escalating soil salinization globally, the AMF R. clarus emerges as a practical approach to ensure cowpea yields and enhance production in deteriorating agricultural lands, especially in saline areas. This can significantly contribute to promoting food security. Full article

Yeast is one of the co-products of ethanol plants, which can be used as a nutritional supplement in animal feed due to its high protein content. Given the importance of yeast contribution to the nutritional properties of DDG (dried distillers’ grains), the aim of this study was to assess how different levels of aeration affect the biomass production and the quality of yeast providing new insights into yeast production, offering an alternative source of income for the corn ethanol industry. For this purpose, yeasts were grown in a fed-batch process, and different concentrations of aeration in the medium were tested, namely 0.5, 1.0, and 1.5 volume of air per volume of wort per minute (v v⁻¹ min⁻¹). At the end of the cellular biomass production process, yeasts grown with 0.5 (v v⁻¹ min⁻¹) aeration in the reactor showed higher biomass formation (19.86 g L⁻¹), cellular yield (g g⁻¹), and a lower formation of succinic acid (0.70 g L⁻¹) and acetic acid (0.11 g L⁻¹). Aeration influenced an increase of 1.0% in the protein content in yeast. In conclusion, lower levels of aeration in the yeast production process enables more efficient sugar utilization for biomass formation and is a potential strategy to increase the protein content and the commercial value of DDG. Full article

White mold (Sclerotinia sclerotiorum de Bary) is one of the most important fungal diseases of winter oilseed rape (OSR). Since the pathogen can persist in the soil for a long time with its sclerotia, prevention and non-chemical methods (specifically biological agents) are important pillars in the integrated plant protection strategy against this pathogen. Mapping the intraspecific variability of the pathogen is an important step in the development of resistance to S. sclerotiorum. S. sclerotiorum isolates were collected from different OSR growing locations in Hungary during the 2020/21 and 2021/22 growing seasons. The morphological characteristics of sclerotia obtained from infected OSR stems were studied in the laboratory, and seedlings of four OSR hybrids were infected in vitro with isolates. The strains from four locations have different morphological characteristics. Significant differences in the level of aggressivity were also observed between strains; a correlation was also found between mycelial growth after 24 h, weight of sclerotia, and aggressivity. Among the four tested hybrids, OSR PT271 proved to be the most susceptible to most S. sclerotinia strains. Full article

This study aimed to investigate the impact of intradermal (ID) and intramuscular (IM) vaccination with a porcine reproductive and respiratory syndrome virus (PRRSV)-modified live vaccine (MLV) in piglets on serum copeptin levels and hematological profile. This study included 104 suckling piglets (2 weeks of age) from a commercial farrow-to-finish pig farm suffering from positive unstable PRRSV status. Animals were assigned to four groups, with two replicates (13 piglets/group/replicate); group A: IM vaccination with a PRRSV MLV vaccine, group B: ID vaccination with the same vaccine, group C: ID of Diluvac Forte, and group D: IM of Diluvac Forte. Blood samples were collected from the same three pigs/group/replicate at 4, 7, and 10 weeks of age. Blood samples were used for the performance of the complete blood count, and they were also examined by PCR for PRRSV and by ELISA for copeptin. No significant differences in serum copeptin levels and the number of blood cell counts (packed cell volume—PCV, numbers of white blood cells—WBCs, and platelets number—PLTs) were noticed in the same group over time and among groups. In conclusion, it seems that the vaccination against PRRSV does not affect the levels of the released copeptin. Based on our results, the measurement of serum copeptin could not be proposed as a potential stress biomarker in pigs. Full article

Magnesium is a key element for plant growth and development. Plant responses to Mg deficiency were well investigated, especially in glycophytes. Such responses include a reduction in plant growth and biomass allocation between shoots and roots, photosynthates partitioning from source to sink organs, the accumulation of carbohydrates, and an induction of several Mg transporters. Some physiological and biochemical parameters are good markers of Mg deficiency stress even though they are not well investigated. In the present study, the halophyte Cakile maritima was subjected to Mg shortage, and several Mg stress indices were analyzed. Our data showed that Mg starvation affected shoot and plant length, leaf number, and plant organ growth. A significant decrease in chlorophyll synthesis and photosynthetic activity was also recorded. Mg deficiency triggered oxidative damage as electrolyte leakage and lipid peroxidation were increased by Mg deficiency while the membrane stability index decreased. For a deeper understanding of the effect of Mg starvation on C. maritima, several tolerance stress indices were evaluated, demonstrating a negative impact of Mg stress on almost all those parameters. This study provided important insights on several markers of Mg deficiency stress, which were informative by themselves as unique and early signals of Mg deficiency stress in this halophyte. Full article

The modern theory of stress, initially proposed by Hans Selye in 1956, signifies an important development in our understanding of this phenomenon. Selye’s The Stress of Life serves as a foundational book for subsequent scientific questions. In this article, we focus on a comprehensive look at stress and use a literature review to explain its theoretical foundations as well as its clinical equivalent. Our research focuses on the complex mechanisms of stress, with a particular emphasis on the consequences of cardiac remodeling and adaptation processes. Myocardial remodeling might be seen as a response to increased stress in acute or chronic situations. Stressed heart morphology (SHM) is a very interesting description representing basal septal hypertrophy (BSH), which is detectable in both acute emotional stress and chronic stress due to increased afterload in hypertension. Acute stress cardiomyopathy (ASC) and hypertension in the same individuals could be clinically linked. Also, in this report, we mention the geometric and functional similarity of the left ventricle (LV) septal base in both acute and chronic clinical situations. Therefore, cardiac imaging methods are crucial to assessing LV segmental aspects in ASC patients. We propose a new paradigm that ASC may develop in hypertensive patients with SHM. We document the segmental progression of microscopic LV remodeling using a third-generation microscopic ultrasound and note that BSH takes a longer time to occur morphologically than an acutely developed syndrome. However, the majority of ASC events have a predominant base, and the absence of segmental remodeling details, including BSH and cardiac decompensation with apical ballooning, on echocardiographic reports may mask the possible underlying hypertensive disease. In fact, beyond ASC cases, previously undiagnosed hypertension is very common, even in developed countries, and is associated with masked target organ damage. Full article

Periods with high precipitation and temporary waterlogging in the humid tropics are challenging to the production and survival of some grasses of the genus Urochloa. This study aimed to evaluate the tolerance of five types of grass belonging to the genus Urochloa under waterlogging conditions through productive and morphological traits. The grasses [U. arrecta (Tanner), U. arrecta x U. mutica (Brachipará), U. brizantha cv. Marandú, U. hybrid cv. Cayman and U. humidicola cv. Llanero] were planted in pots and kept under field capacity for 33 days; then, half of them were submitted to (i) field capacity (33% humidity retention) and the other half were submitted to (ii) waterlogging conditions (2 cm of water above soil level) for 28 days. In this study, Tanner and Brachipará grasses showed higher dry shoot mass under waterlogging conditions, which were followed by Llanero, Cayman, and Marandú, respectively. Llanero, Tanner, and Brachipará presented higher waterlogging tolerance coefficients, 78.7, 76.5, and 64.5, respectively, being less affected than Cayman and Marandú (41.0 and 23.1, respectively). Brachipará, Tanner, and Cayman presented a higher root volume under waterlogging conditions, while Marandú root volume decreased by 88.77%. The Tanner, Brachipará, and Llanero genotypes were more tolerant to poorly drained or waterlogged soils than Cayman and Marandú genotypes. Full article

Fetal growth restriction (FGR) and low birth weight increase the risk of non-communicable diseases such as type 2 diabetes and heart failure in adulthood. Placental insufficiency is widely considered a major contributor to FGR. Two crucial placental proteins involved in nutrient and stress sensing—O-linked N-acetylglucosamine transferase (OGT) and mechanistic target of rapamycin (mTOR) kinase—play roles in post-translational protein modification and protein translation, influencing cellular growth and metabolism in response to maternal stress, hypoxia, and nutritional status in the placenta. In our study, we examined the gene and protein profiles of OGT and mTOR in FGR and control placentae, comparing those appropriate for gestational age (AGA), while also considering potential confounding effects of fetal sex and delivery mode. Our findings revealed no significant differences in gene expression, protein levels, or activity of OGT, OGA, mTOR, or their associated markers between female AGA and FGR cesarean placentae, nor between female AGA and male AGA cesarean placentae. Additionally, the mode of delivery in female AGA placentae did not affect the levels or activity of these proteins. Overall, our study did not observe significant differences in nutrient sensor protein expression after stratifying by FGR, sex, and delivery mode. Nevertheless, these unbiased results provide a more comprehensive understanding of the complexities of placental gene expression involving OGT and mTOR. Full article

This study aimed to investigate the effects of a polyphenolic phytogenic feed additive (PFA) based on plant extracts, such as Embelia officinalis, Ocimum sanctum and nut fibre, on the redox status, haematological parameters, and piglet mortality in sows. A total of 64 primiparous sows were divided into two groups: T1-control group: regular gestation (GF) and lactation feed (LF), T2 group: regular GF and LF supplemented with a PFA (10 g daily) for 14 days before and 7 days after the farrowing. Blood samples were collected 0–3 h after farrowing. Haematological parameters (Packed Cell Volume/PCV, White Blood Cells/WBC, Platelets/PLTs) were counted in blood smears. Thiobarbituric acid reactive substances (TBARS) and protein carbonyls (CARBS) levels were determined in sow plasma. The performance and reproductive parameters of sows at farrowing and weaning days were recorded. The mean numbers of PCV and PLT counts in the T2 group were higher in comparison to the T1 group (p = 0.041, p = 0.033, respectively). In contrast, the mean numbers of WBC and neutrophils were almost significantly higher in the T2 group (p = 0.051). The mean number of stillborn piglets was significantly higher in the T1 group (2.12) compared to the T2 group (1.03). The mean number of alive piglets 24 h after farrowing and the mean number of the weaned piglets were significantly higher in group T2 (13.9 vs. 15.4 and 12.6 vs. 14.3). Sows in group T2 had significantly more backfat at weaning than the sows in group T1 (13.3 vs. 12.7). The mean levels of CARBS (nmol/mL) and TBARS (μmol/L) in group T1 (24.8 and 18.7) were significantly higher in comparison to group T2 (18.3 and 14.9). In conclusion, the use of a polyphenolic PFA in sows has beneficial effects on their welfare and performance due to its antioxidative effects. Furthermore, PFAs appear to exert antithrombotic, anti-inflammatory, and protective effects on PLTs, WBCs, and RBCs, respectively. Full article

Salinity is a significant factor restricting plant growth and production. The effect of salinity stress on different growth parameters of 111 fenugreek genotypes was examined in an experiment with three salinity levels (0, 3000, 6000 mgL⁻¹). A completely randomized block design with two replicated pots per treatment was used. Non-significant treatment effects were observed on fresh weight (FW); however, all traits showed significant genotype-by-treatment (GxT) interactions. This GxT was reflected in substantial SNP x environment interactions. Of 492 significant SNPs associated with the measured traits, 212 SNPs were linked to the correlated traits using an arbitrary threshold of three. Several SNPs were associated with FW and dry weight, measured under the same salinity treatment. The correlation between both traits was 0.98 under the three salinity treatments. In addition, 280 SNPs with conditional neutrality effects were mapped. The identified SNPs can be used in future marker-assisted breeding programs to select salt-tolerant genotypes. The results of this research shed light on the salt-tolerant properties of fenugreek. Full article

An imbalance between the formation of reactive oxygen species (ROS) and the reaction of antioxidant proteins is referred to as oxidative stress. NFE2L2/Nrf2, also known as nuclear factor erythroid-derived 2-related factor 2, is a critical enabler of cytoprotective responses to oxidative and electrophilic insults. When Nrf2 is activated, it triggers the transcription of numerous cytoprotective genes, whose promoter regions contain antioxidant response elements (AREs). In recent times, the regulation of Nrf2 by miRNAs has garnered significant attention, among the various mechanisms that govern Nrf2 signaling. It has been reported that a number of miRNAs directly suppress the expression of Nrf2s, which in turn negatively regulates the Nrf2-dependent cellular cytoprotective response. Furthermore, it has been shown that Nrf2 itself regulates miRs, which carry out some of Nrf2’s unique metabolic regulation functions. Here, we provide an overview of the functions and mechanisms of action of miRs as downstream effectors of Nrf2, as well as in their regulation of its activity. Full article

Here, we hypothesized the occurrence of a compensatory relationship between the application of P and different microbial communities in the soil, specifically in relation to the chemical and biological effects in the soil–plant–microorganisms’ interaction. We aimed to evaluate the plant–microbiota responses in plants grown in soils hosting distinct microbial communities and rates of P availability. Two experiments were carried out in a greenhouse. The first experiment evaluated four manipulated soil microbiome compositions, four P rates, and two plant species. Manipulated soil systems were obtained by the following: (i) autoclaving soil for 1 h at 121 °C (AS); (ii) inoculating AS with soil suspension dilution (AS + 10⁻³); (iii) heating natural soil at 80 °C for 1 h (NH80); or (iv) using natural soil (NS) without manipulation. The P rates added were 0, 20, 40, and 60 mg kg⁻¹, and the two plant species tested were grass (brachiaria) and leguminous (crotalaria). Inorganic labile P (P_AER), microbial P (P_MIC), acid phosphatase activity (AP_ASE), and shoot P uptake (P_UPT) were assessed for each system. Brachiaria presented a compensatory effect for P_UPT, whereby the addition of P under conditions of low microbial community enhanced P absorption capacity from the soil. However, in a system characterized by low P input, the increase in the soil biodiversity was insufficient to enhance brachiaria P_UPT. Likewise, crotalaria showed a higher P_UPT under high P application and low microbial community. The second experiment used three manipulated microbiome compositions: AS + 10⁻³; NH80; and NS and three P rates added: 0, 20, and 40 mg kg⁻¹. In addition, two treatments were set: without and with mycorrhiza inoculation. Brachiaria showed an increase in the P_UPT under low microbial communities (AS + 10⁻³; NH80) with P addition (20 and 40 mg kg⁻¹ of P), but no mycorrhization was observed. In the undisturbed microbial community (NS), under no P input (0 mg kg⁻¹ of P), brachiaria showed low mycorrhization and low P_UPT. Finally, NS and the recommended P input (40 mg kg⁻¹ of P) represented a balance between chemical and biological fertility, promoting the equilibrium between mycorrhization and P_UPT. Full article

The competitive calendars in sports often lead to fluctuations in the effort-recovery cycle and sleep quality. NESA noninvasive neuromodulation, achieved through microcurrent modulation of the autonomic nervous system, holds promise for enhancing sleep quality and autonomic activation during stressful situations. The objective of this study was to analyze the sleep and recovery responses of basketball players over six weeks of training and competition, with the integration of NESA noninvasive neuromodulation. A preliminary experimental study involving 12 participants was conducted, with a placebo group (n = 6) and an intervention group (n = 6) treated with NESA noninvasive neuromodulation. Sleep variables and biomarkers such as testosterone, cortisol, and the cortisol:testosterone ratio were analyzed to assess player recovery and adaptations. Significant differences were observed in total, duration, and REM sleep variables (p-value= < 0.001; 0.007; <0.001, respectively) between the intervention and placebo groups. The intervention group demonstrated increased duration of sleep variables. Cortisol levels showed normalization in the experimental group, particularly in the last two weeks coinciding with the start of playoffs. This study highlights the potential of NESA noninvasive neuromodulation to enhance sleep quality despite challenging circumstances, providing valuable insights into the management of athlete recovery in competitive sports settings. Full article

An understudied problem in plant heavy metal biology is the effects of acute versus gradual or chronic metal exposure. The aim of the present study was to compare the growth and physiological responses of Rumex hydrolapathum Huds. plants subjected to gradual or acute Mn stress treatment in controlled conditions. Heavy metal was applied to substrate either as one 1.00 g L⁻¹ Mn dose (acute treatment) or the same dose in four steps of increasing amounts within 12 days (gradual treatment). Peroxidase activity in actively photosynthesizing leaves was used for monitoring induced biochemical changes resulting from Mn treatment. The number of leaves per plant significantly increased in the case of gradual treatment with Mn, but this effect was not statistically significant for acute treatment. Leaf fresh mass significantly decreased in both cases due to the decrease in leaf water content, but dry biomass of leaves was not affected, with no significant differences between the two types of treatments. A significantly lower chlorophyll fluorescence parameter Performance Index in large leaves of plants under the acute Mn treatment than in plants under the gradual treatment was evident. An increase in leaf peroxidase activity by Mn treatment was proportional to the metal dose received, but plants in the acute treatment with 1.00 g L⁻¹ Mn had a significantly lower peroxidase response in comparison to the gradual treatment with 1.00 g L⁻¹ Mn. In conclusion, under gradual treatment, biochemical changes related to the induction of tolerance to the heavy metal are expressed, as indicated by the continuous increase in leaf peroxidase activity after each treatment step. Full article

Tomato cultivation grapples with salt stress, disrupting growth parameters and physiological processes. High salinity levels induce osmotic stress, impacting cellular integrity and hindering metabolic activities. Salt accumulation at the root zone alters key physiological attributes, compromising overall harvestable output. Seed priming emerges as a potential solution to enhance plant resilience. A research gap exists in understanding the combined influence of polyethylene glycol and sodium chloride as seed priming agents under salt stress conditions. The study occurred in the Greenhouse of Laboratory Horticultural Science at Tokyo University of Agriculture. Micro Tom seeds underwent a factorial randomized design, involving five salinity and four priming treatments. Replicated ten times, totaling 200 plants, seed priming used polyethylene glycol, inducing salinity stress with sodium chloride. Meticulous measurements of growth parameters, photosynthetic traits, yield attributes, and electrolyte leakage were conducted. Statistical analyses discerned treatment effects at a 5% significance level. Seed priming, especially with ‘PEG plus NaCl’, effectively mitigated salt stress effects on tomato plants. Under severe salt stress, primed plants exhibited increased plant height, trusses, leaves, and leaf area. Photosynthetic efficiency and yield attributes demonstrated significant improvements with seed priming. Electrolyte leakage, indicative of leaf damage, was notably reduced by seed priming treatments, with ‘PEG plus NaCl’ exhibiting the highest efficacy. These results offer valuable guidance for optimizing agricultural practices in saline environments, contributing to sustainable strategies for food security amidst escalating environmental challenges. Full article