Normal Stress Conditions Research Articles

A plant endophytic bacterium Burkholderia seminalis strain 869T2 increases plant growth under salt stress by affecting several phytohormone response pathways.

Due to global warming and gradual climate change, plants are subjected to a wide range of environmental stresses, adversely affecting plant growth and production worldwide. Plants have developed various mechanisms to overpower these abiotic stresses, including salt stress, drought, and high light intensity. Apart from their own defense strategies, plants can get help from the beneficial endophytic bacteria inside host plants and assist them in enduring severe growth conditions. A previously isolated plant endophytic bacteria, Burkholderia seminalis 869T2, from vetiver grass can produce auxin, synthesize siderophore, and solubilize phosphate. The B. seminalis 869T2 can colonize inside host plants and increase the growth of bananas, Arabidopsis, and several leafy vegetables. We further demonstrated that different growth parameters of Arabidopsis and pak choi plants were significantly increased after inoculating the B. seminalis 869T2 under normal, salt, and drought stress conditions compared to the mock-inoculated plants. Both transcriptome analysis and quantitative real-time PCR results showed that expression levels of genes related to phytohormone signal transduction pathways, including auxin, gibberellin, cytokinin, and abscisic acid were altered in Arabidopsis plants after inoculated with the strain 869T2 under salt stress, in comparison to the mock-inoculated control with salt treatments. Furthermore, the accumulation levels of hydrogen peroxide (H2O2), electrolyte leakage (EL), and malondialdehyde (MDA) were lower in the 869T2-inoculated Arabidopsis and pak choi plants than in control plants under salt and drought stresses. The plant endophytic bacterium strain B. seminalis 869T2 may affect various phytohormone responses and reduce oxidative stress damage to increase salt and drought stress tolerances of host plants.

Inoculation of methylotrophs mitigates heat and UV stress in mung bean (Vigna radiata L.) and enhances growth, antioxidant, and functional diversity.

Climate change involves the induction of heat and solar ultraviolet (UV) radiation, which profoundly affects sustainable crop production. Increasing solar UV radiation negatively impacts the photosynthetic apparatus, plant-associated organisms, and plant health. The present study aimed to comprehensively assess methylotrophic bacteria to alleviate heat and UV radiation in Vigna radiata L. under pot studies and field conditions. Under normal and UVB stress conditions, inoculation of methylotrophs significantly enhanced seed germination (72.55%-96.70% (normal)and 51.67%-65.33% (stressed)) and improved plant growth parameters, total chlorophyll (25.80-48.16 mg/g (normal) and 9.13-27.88 mg/g (stressed)), and carotenoid (569.1-1067.1 μg/g (normal)and 287.8-903.4 μg/g (stressed)) contents. A similar enhancement in antioxidant properties such as superoxide dismutase (1-5 fold), peroxidase (1-9 fold), phenylalanine ammonia lyase (1-4 fold), and proline content (1-5 fold) was observed in response to UVB radiation and heat stress under pot studies. A community-level physiological profile (CLPP) study of leaf samples revealed enhanced AWCD in methylotrophs treated plants compared to the UVB-exposed controls. Furthermore, field studies in summer conditions confirmed that inoculation with methylotrophs had a positive effect on V. radiata growth and physiology. The methylotrophs inoculation increased pod formation (25.44-32.78 and 15.56-32.00) and yield (109.81-238.63 and 71.88-216.29 q/ha) under UV cut-off sheet covered and non-covered conditions, respectively. This study demonstrated the potential of methylotrophs to mitigate heat and solar (UV) radiation in plants and provide sustainable strategies for agriculture and the environment.

Effect of nutritional stress and serum starvation on the optical absorbance of normal and malignant epithelial cell lines.

This brief report aimed to investigate the optical absorbance spectra of normal, dysplastic, and malignant epithelial cell lines under normal and nutritional stress conditions. HaCAT (keratinocyte), DOK (oral dysplastic), and oral squamous cell carcinoma (OSCC) cell lines (CA1, Luc4, SCC9) were evaluated regarding their optical absorbance after culture with 0-10% fetal bovine serum. Absorbance measurements indicated that HaCAT under serum starvation exhibited higher absorbance at blue (430nm) and near-infrared (906nm) wavelengths. DOK showed absorption at 440nm and 945nm. OSCC cells showed absorption peaks at blue (400-428nm) and near-infrared. These findings highlight the importance of tailoring PBM parameters to individual needs to achieve optimal absorption and effectiveness. Moreover, the higher absorption peaks in the blue region support further studies to elucidate the potential use of blue light in oral dysplastic lesions and OSCC.

Biotechnological Phytocomplex of Zanthoxylum piperitum (L.) DC. Enhances Collagen Biosynthesis In Vitro and Improves Skin Elasticity In Vivo.

Background:Zanthoxylum piperitum (L.) DC., commonly known as Japanese pepper, is a deciduous shrub native to East Asia. Its berries are widely used as a spice, known for imparting a distinctive, tingly numbing sensation. Biologically, Z. piperitum has antimicrobial, antioxidant, and anti-inflammatory properties, and it is studied for its potential benefits in pain relief and digestive health. This study proposed a novel biotechnological Z. piperitum phytocomplex (ZPP) obtained by plant cell culture for skin health, specifically targeting collagen synthesis, extracellular matrix stability, and resilience against cellular stress. Given the bioactivity of Z. piperitum, we aimed to analyze its efficacy as a sustainable alternative for skin-supportive applications in cosmetics and supplements. Methods: ZPP was produced through stable plant cell cultures, yielding a lignan-rich (3.02% w/w) phytocomplex. Human fibroblasts (HFFs) were treated with varying ZPP concentrations to assess cellular viability, collagen metabolism, and ECM-related enzyme activities, both under normal and cell stress conditions. The in vivo assessment was performed by measuring biophysical skin parameters such as hydration, elasticity, and roughness in female volunteers for a period of six weeks. Results: In vitro, ZPP exhibited non-cytotoxicity at all concentrations tested. Under hyperosmotic stress, ZPP reduced cellular damage, suggesting enhanced resilience. ZPP upregulated lysyl oxidase (LOX) protein levels, critical for collagen cross-linking and ECM stability, with protective effects observed under oxidative/inflammatory conditions. Additionally, ZPP selectively inhibited collagenase, attenuating collagen breakdown, though antioxidant activity was modest. In vivo evaluation highlighted improved skin hydration, elasticity, and roughness. Conclusions: ZPP shows promise as a biotechnological agent for skin health, particularly in supporting collagen integrity, ECM stabilization, and cellular resilience under stress. While further studies are needed to explore its full efficacy, especially for aging and environmentally stressed skin, these findings highlight ZPP's potential as a new ingredient for cosmetic formulations aimed at skin care and the treatment of alterations caused by aging or environmental conditions.

Root growth in transgenic tobacco plants with overexpression of the PtrXTH1 gene encoding xyloglucan endotransglycosylase under abiotic stress

Xyloglucan endotransglycosylases are hydrolytic cell wall enzymes that are involved in the regulation and promotion of plant growth. Overexpression of genes encoding xyloglucan endotransglycosylases can have a positive effect on the growth and stress tolerance of transgenic plants; however, the mechanisms of such influence remain poorly understood. This study was aimed at creating transgenic tobacco plants with overexpression of the PtrXTH1 gene encoding aspen xyloglucan endotransglycosylase, as well as conducting a morphophysiological analysis of their roots under abiotic stress. The transgenic tobacco plants were characterized by an increased root length as compared to wild plants, both under optimal conditions and in response to salinity (100 mM sodium chloride), low temperature (12 °C), and cadmium contamination (200 μM cadmium acetate). The area of root parenchyma cells in transgenic tobacco plants is larger as compared to wild plants only under the effect of cadmium acetate, whereas under normal conditions and under low-temperature and salinity stress, no difference in cell size was observed. The PtrXTH1 gene overexpression contributed to the increased total antioxidant capacity in the roots, as well as a higher content of proline, water-soluble sugars, and oxidized and reduced glutathione, in the context of the three stress factors. Thus, the PtrXTH1 transgene stimulates the growth of tobacco roots under normal and abiotic stress conditions, which is accompanied by positive changes in the antioxidant system.

Heat Tolerance Differences Between Hu Sheep and Hu Crossbred Sheep in Microbial Community Structure and Metabolism.

The frequent occurrence of extreme temperature events causes significant economic losses to the livestock industry. Therefore, delving into the differences in the physiological and molecular mechanisms of heat stress across different sheep breeds is crucial for developing effective management and breeding strategies. This study explores the differences in heat tolerance mechanisms between Hu sheep and Xinggao sheep by comparing their growth performance under normal and heat stress conditions, as well as examining the differences in physiological, biochemical, and antioxidant indicators related to heat tolerance, serum metabolomics, and gut microbiomics in a heat stress environment. The results indicate that with changes in the temperature-humidity index (THI), Hu sheep exhibit superior stability in respiratory rate (RR) and rectal temperature (RT) fluctuations compared to Xinggao sheep. In terms of biochemical indicators and antioxidant capacity, the levels of creatinine (Cr) and superoxide dismutase (SOD) in Hu sheep serum are significantly higher than those in Xinggao sheep. In comparison, alkaline phosphatase (ALP) and malondialdehyde (MDA) levels are significantly lower. Metabolomic results showed that, compared to Hu sheep, Xinggao sheep exhibited higher cortisol (COR) and dopamine (DA) levels under heat stress conditions, a stronger lipid mobilization capacity, and elevated levels of tricarboxylic acid (TCA) cycle-related metabolites. Furthermore, gut microbiome analysis results indicate that Hu sheep demonstrate stronger cellulose degradation capabilities, as evidenced by significantly higher abundances of microorganisms such as Ruminococcus, Fibrobacter, and Bacteroidales_RF16_group, compared to Xinggao sheep. In summary, Hu sheep exhibit stronger heat tolerance compared to Xinggao sheep. These findings provide an important theoretical basis for the breeding and selection of heat-tolerant meat sheep varieties and offer strong support for the region's livestock industry in addressing the challenges posed by global warming.

Tensile deformation damage behavior of high strain submarine pipeline steel with ferritic and bainitic dual phase under normal and shear stress conditions

Tensile deformation damage behavior of high strain submarine pipeline steel with ferritic and bainitic dual phase under normal and shear stress conditions

The Effect of Aloe Leaf Extract on Growth and Physio-biochemical Characteristics of Jojoba Plants Cultivated under Normal and Salt Stress Conditions

The Effect of Aloe Leaf Extract on Growth and Physio-biochemical Characteristics of Jojoba Plants Cultivated under Normal and Salt Stress Conditions

Estimation of stress tolerance indices for identification of heat tolerant genotypes in barley

Abstract The objective of present study was to assess the heat tolerance of barley genotypes employing a set of 12 heat stress indices namely SSI, TOL, STI, SSPI, YI, YSI, RSI, MP,GMP, HM, MRP and RED, estimated using grain yield. A total of 29 barley genotypes were evaluated under normal (non-stress) and heat stress conditions during 2021-22 crop season with four replications in randomized block design (RBD) at Research Area, Department of Genetics and Plant Breeding, CCS Haryana Agricultural University, Hisar (Haryana). The genotypes, DWRB 91, BH 20-40, BH 20-05, BH 20-07 and BH 19-15 were found to be heat tolerant based on average rank of SSI for different traits. However, based on overall rank of stress indices employed on grain yield, BH 19-13, BH 20-40, BH 393, BH 19-15, BH 20-02 and BH 946 were found prominent with tolerance to heat stress. Grain yield (Ys) showed negative association with SSI, RSI and RED and significant positive correlation with the indices viz., STI, YI, MP, GMP and HM. Hence these indices could be regarded as the best selection indicators for heat stress tolerance. PCA study considered second principal component (PC 2) as heat tolerant component based on strong correlation with STI, YI, YSI, MP, GMP, HM, MRP and Ys under stress condition. The genotypes of cluster I exhibited better performance under stress condition for grain yield (Ys) and SSI, TOL, SSPI, RSI, RED, YI, YSI, and MRP. The genotypes from this group could be utilized as promising breeding material for development of new heat tolerant barley cultivars. Keywords: Barley, correlation, cluster analysis, PCA, stress indices, heat tolerance

The Effects of Elite Puroindoline Gene Alleles on the Kernel Hardness of Chinese Winter Wheat

Kernel hardness (KH) is a significant factor that influences wheat quality. In order to gain a better understanding of KH profiles and the effects of its associated genes in Chinese wheat cultivars growing under normal and latest stage drought stress conditions, 206 wheat cultivars were examined. The kernel hardness index (KHI) was measured by utilizing a single kernel hardness tester, and allelic variations of the puroindoline genes regulating KH were detected using KASP markers. The hardness test indicated that 121 (58.7%) were classified as hard wheat, 39 (18.9%) as soft wheat, and 46 (22.3%) as mixed wheat. Genotypic analysis revealed that 10 cultivars (4.9%) carried the superior Pina-D1b allele, 143 cultivars (69.4%) possessed the Pinb-D1b allele, representing the main allele for hard wheat, and 45 cultivars (21.8%) contained the Pinb-B2b allele. An analysis of the cumulative effect across five gene loci indicated that among the tested materials, none contained all five excellent gene loci simultaneously. However, materials with combinations of two, three, or four excellent gene loci exhibited significantly higher KHI values compared to those with zero or only one excellent locus. This finding suggests that the accumulation of excellent gene loci can enhance KH. Among various allelic combinations, Pina-D1 + M0159 displayed remarkably higher KH values than the others. Conversely, Pinb-D1 + M0380 exhibited significantly lower KH values. Drought stress during the late growth stage of wheat could enhance KH.

Effect of normal irrigation and water stress conditions on some characteristics of cotton in Toshka region -Egypt

Irrigation, water stress, planting dates and planting distances are crucial for obtaining desirable fiber properties for Egyptian cotton, especially under climate change. Two field experiments were carried out at the Water Studies and Research Complex (WSRC) station, National Water Research Center, Toshka, Egypt in the 2021 and 2022 growing seasons, to evaluate some morphological traits and fiber quality properties of the Egyptian cotton cultivar Giza 95 under three planting dates (january, february, and march) and 6 planting distances (10, 15, 20, 25, 30, and 35 cm among plants), comparing them with two irrigation treatments (100% A.W. and 80 % A.W.). The main effects of irrigation treatments, planting dates, and planting distances in both seasons were found to be significant (P<0.05 or 0.01) for most morphological and fiber quality properties under study. Also, the first-order interactions of irrigation treatments with planting dates, and planting distances have significant effects (P<0.05 or 0.01) on most studied traits in both seasons. In both seasons, positive effects were observed for the number of fruiting branches, plant height, and fiber fineness traits with irrigation treatment (80 % A.W.) and other fiber quality properties with irrigation treatment (100% A.W.). When compared to other planting dates in both seasons, the February planting date produced the best values for the majority of the analyzed traits, however, the January planting date produced a higher number of fruiting branches. Wider plant spacing produced the best results for fiber quality properties, whereas 10 cm spacing between plants resulted in more fruiting branches. Based on mean performances and principle component analysis, the February planting date with wider plant spacing under irrigation treatment (80% A.W) may be a better method to improve fiber quality properties in the experimental region under study. Additionally, these data will help develop plans for better agricultural practices and enhancing Egyptian cotton's fiber quality

Variability Studies in Soybean Genotypes under Different Water Regimes

Soybean (Glycine max L.) is economically one of the most important oilseed crop worldwide which have high protein and oil content. Its productivity is frequently affected due to drought occurrence in India. Variability for root shoot traits under early seedling stage under drought stress may be important selection criteria for development of drought tolerant genotypes. The present investigation was carried out at Net house of Experimental Farm, Mandsaur University, Mandsaur. Sixty genotypes, procured from ICAR-IISR, were used to know the extent of genetic variability under different water regimes [normal, 100 ml (100%), S1, 50 ml (50%), S2, 25 ml (25%) and S3,0 ml (0%)] for root-soot traits and relative leaf water content under early seedling stage. Significant genetic variability was recorded for all the traits among genotypes studied under normal and water stress conditions respectively which showed the presence of ample variability in studied material. High Phenotypic Coefficient of Variation than their corresponding Genotypic Coefficient of Variation for the entire trait under different water regimes denoted influence of environment on these traits. The large genetic variation found in these genotypes may be used to develop varieties with better drought tolerance behavior and used as drought donor lines in drought breeding programs. We measured high heritability for selected characters under non water stress condition (75.05% to 100%) and water stress conditions S1 (81.40% to 100%), S2 (85.69% to 100%) and S3 (92.60% to 99.26%) respectively. Additive gene action interacted to control characters under different water regimes because high broad sense heritability along with high genetic advance as percentage of mean were recorded for most of traits. It is indicating that simple phenotypic selection would be effective for these traits under water stress condition.

Numerical investigation of bolted rock joints under varying normal stress and joint roughness coefficient conditions

Rock masses are formed through long-term, complex geological processes, and the presence of joints significantly reduces their strength and increases their deformation. Rock bolts effectively enhance the strength and stability of rock masses and are extensively utilized for reinforcement. According to field investigations, a significant portion of the damage to bolted rock masses stems from shear deformation at joint surfaces. Moreover, roughness affects friction and surface contact, thus influencing the shear behavior between rock and rock bolts. This study considers two crucial factors affecting the shear characteristics of bolted rock joints: joint surface roughness and normal stress. Using the Particle Flow Code discrete element numerical method, the Barton standard joint profile lines were input to establish numerical models of both unbolted and bolted rock joints for direct shear tests. Results reveal that the peak shear stress and stiffness of both unbolted and bolted rock joints increase with rising normal stress and joint roughness coefficient. The peak shear stress and stiffness of bolted rock joints are notably higher than those of unbolted ones, with a maximum increase of 17.5%. Crack development in bolted rock joints occurs in stages of rapid, slow, and stable development, whereas no distinct slow development stage is observed in unbolted rock joints. Additionally, micro cracks in both unbolted and bolted rock joints are primarily tensile cracks, originating around the joint surface and extending outward with increasing shear displacement. These findings offer valuable insights into the microscopic shear mechanics of bolted rock joints and provide practical references for engineering design and applications in rock reinforcement projects.

MsDUF3700 overexpression enhances aluminum tolerance in alfalfa shoots.

This study identified a gene associated with aluminum stress through GWAS, which regulates aluminum tolerance in alfalfa by contributing to the antioxidant system. Aluminum (Al) ions precipitate in acidic soils with a pH < 5.5, where they are absorbed alongside other nutrients by plants, negatively impacting plant growth. Alfalfa, the most widely grown perennial legume forage in the world, is especially vulnerable to acidic soil conditions. Our research pinpointed MsDUF3700 as a potential gene linked to Al-response traits via genome-wide association analysis in Medicago sativa. MsDUF3700 encodes the domain of unknown function (DUF). We observed higher expression of MsDUF3700 in Al-tolerant alfalfa compared to Al-sensitive ecotypes. MsDUF3700-overexpressing transgenic alfalfa (MsDUF3700-OE) showed shorter root elongation and higher Al accumulation in roots than wild type (WT) under Al conditions. However, the shoots of MsDUF3700-OE lines showed enhanced growth rates under both normal and Al stress conditions. Under Al stress, MsDUF3700-OE lines showed increased H2O2 and malondialdehyde (MDA) levels in the roots, alongside reduced catalase activity, In contrast, the shoots showed an inverse trend. In addition, we found that MsDUF3700-OE alfalfa plants had high Al accumulation in the roots and low Al accumulation in the shoots. Transcripts of MsALS3 and MsPALT1, homologs of Al translocation in alfalfa, were downregulated, while MsNrat1, a homolog of transporters absorb Al, was upregulated in the roots of MsDUF3700-OE in alfalfa. Our research indicates that MsDUF3700 plays a role in aluminum stress by participating in antioxidative defense and facilitating aluminum transport from roots to shoots.

Experimental Evidence for Reaction‐Induced Weakening of (Carbonated) Serpentinite Fault Gouges

AbstractThe seismic potential of faults depends on the local mineralogy and can change upon mineral reactions. We conducted friction experiments on serpentinite, carbonate and carbonated serpentinite fault gouges at temperatures from 400°C to 630°C, under 100 MPa effective normal stress and fluid saturated conditions. Pure serpentinite fault gouges exhibited unstable slip with significant strain‐hardening. Carbonate‐bearing serpentinite fault gouges showed stable sliding at temperatures &lt;500°C, but displayed unstable stick‐slip behavior and strong strain weakening at temperatures ≥500°C. Microstructural analyses revealed localization and the formation of olivine and pyroxene from devolatilization reactions at temperatures ≥500°C. The degree of devolatilization increased near major slip planes and was enhanced by higher temperature and carbonate content, as shown by three‐dimensional micro‐computer tomography analyses. Nano‐scale transmission electron microscopy analyses revealed the absence of hydrous and carbonate phases along major slip planes. We attribute the strong weakening and unstable slip behavior in carbonated serpentinite fault gouges to the formation of nano‐sized anhydrous phases of olivine and pyroxene along the slip plane. Our results indicate that serpentinized fault zones may experience seismic event nucleation at temperatures approaching the thermodynamic stability limit of serpentine. This suggests that the absence of seismic events cannot exclusively be attributed to serpentinization. The formation of carbonates, through replacive and additive carbonation, can explain aseismic deformation in transform faults, but at elevated temperatures, devolatilization reactions in carbonated serpentinites cause strong localization and strain weakening, accompanied by laboratory seismicity.

Improving grain yield and salt tolerance by optimizing plant height with beneficial haplotypes in rice (Oryza sativa).

Rice (Oryza sativa L.), a staple food for billions worldwide, is challenged by salt stress. Owing to the limited understanding of the physiological and genetic basis of rice salt tolerance, few genes have been identified as valuable in rice breeding, causing a major bottleneck in the development of high-yield, salt-tolerant rice varieties. This study aims to identify salt tolerance genes/quantitative trait loci (QTLs) with breeding potential in rice. Field trials were conducted with 166 Chinese rice cultivars from saline-affected regions and 412 global rice accessions to assess salt tolerance. Genome-wide association study (GWAS) was performed to identify key loci related to high yield and salt tolerance. Additionally, the impact of introducing beneficial haplotypes on grain yield and salt tolerance was assessed. The optimal rice plant height of 100-120 cm was crucial for sustaining high yield under both normal and salt stress conditions. GWAS revealed 6 novel QTLs/genes associated with rice plant growth and grain yield across various environments, distinct from previously recognized salt stress-related genes. Notably, the gene PHS10.1, encoding a serine/threonine protein kinase, may regulate carbon metabolism, starch and sucrose metabolism, influencing plant growth and grain yield. Certain haplotypes of the genes regulating plant height and grain yield, including SD1, Ghd7.1, GH3.5, and PHS10.1, were selected in traditional breeding. Moreover, optimizing plant height through the introgression of beneficial alleles of these genes increased grain yield in recipient lines under both normal and saline conditions. We propose that utilizing beneficial haplotypes to optimize plant height can effectively balance the growth-stress trade-offs in rice plants. This represents a promising breeding strategy for the development of crop varieties that are both high-yielding and salt-tolerant.

PGPB Isolated from Drought-Tolerant Plants Help Wheat Plants to Overcome Osmotic Stress.

The aim of this research was to study the effect of plant-growth-promoting bacteria (PGPB) isolated from the drought-tolerant plants camel thorn (Alhagi pseudoalhagi (M.Bieb.) Fisch) and white pigweed (Chenopodium album L.) on wheat (Triticum aestivum L.) plants cv. Lenigradskaya 6, growing under hydroponic conditions and osmotic stress (generated by 12% polyethylene glycol-6000 (PEG)). Based on the assumption that plants create a unique microbiome that helps them overcome various stresses, we hypothesized that bacteria isolated from drought-tolerant plants may assist cultivated wheat plants in coping with drought stress. PGPB were isolated from seeds and leaves of plants and identified as Bacillus spp. (strains Cap 07D, Cap 09D, and App 11D); Paenibacillus sp. (Cap 286); and Arthrobacter sp. (Cap 03D). All bacteria produced different phytohormones such as indole acetic acid (IAA), abscisic acid (ABA), and gibberellic acid (GAS3) and were capable of stimulating wheat growth under normal and osmotic stress conditions. All PGPB reduced the malondialdehyde (MDA) content, increased the total chlorophyll content by increasing chlorophyll a, and modulated wheat hormone homeostasis and CAT and POX activities under osmotic conditions. Selected strains can be promising candidates for the mitigating of the drought stress of wheat plants.

Distribution of the p66Shc Adaptor Protein Among Mitochondrial and Mitochondria-Associated Membranes Fractions in Normal and Oxidative Stress Conditions.

p66Shc is an adaptor protein and one of the cellular fate regulators since it modulates mitogenic signaling pathways, mitochondrial function, and reactive oxygen species (ROS) production. p66Shc is localized mostly in the cytosol and endoplasmic reticulum (ER); however, under oxidative stress, p66Shc is post-translationally modified and relocates to mitochondria. p66Shc was found in the intermembrane space, where it interacts with cytochrome c, contributing to the hydrogen peroxide generation by the mitochondrial respiratory chain. Our previous studies suggested that p66Shc is localized also in mitochondria-associated membranes (MAM). MAM fraction consists of mitochondria and mostly ER membranes. Contact sites between ER and mitochondria host proteins involved in multiple processes including calcium homeostasis, apoptosis, and autophagy regulation. Thus, p66Shc in MAM could participate in processes related to cell fate determination. Due to reports on various and conditional p66Shc intracellular localization, in the present paper, we describe the allocation of p66Shc pools in different subcellular compartments in mouse liver tissue and HepG2 cell culture. We provide additional evidence for p66Shc localization in MAM. In the present study, we use precisely purified subcellular fraction isolated by differential centrifugation-based protocol from control mouse liver tissue and HepG2 cells and from cells treated with hydrogen peroxide to promote mitochondrial p66Shc translocation. We performed controlled digestion of crude mitochondrial fraction, in which the degradation patterns of p66Shc and MAM fraction marker proteins were comparable. Moreover, we assessed the distribution of the individual ShcA isoforms (p46Shc, p52Shc, and p66Shc) in the subcellular fractions and their contribution to the total ShcA in control mice livers and HepG2 cells. In conclusion, we showed that a substantial pool of p66Shc protein resides in MAM in control conditions and after oxidative stress induction.

VARIABLE FRICTION MODEL DEVELOPMENT AND IMPLEMENTATION TO THE PULLING FORCE PREDICTION OF THE SPLIT-SLEEVE COLD EXPANSION PROCESS FOR ALUMINUM 2024-T3

Abstract This study aims to improve the accuracy of the pulling force estimation by establishing the variable friction model of the dry-lubricated split sleeve when cold working an aluminum 2024-T3 hole. The variable friction model was empirically obtained from the friction experimental setup simplified from the split-sleeve cold expansion process. The contact-pressure-dependent variable friction model was derived through a systematic design of experiments approach with three different normal stress conditions, namely low normal stress (220 MPa), medium normal stress (440 MPa), and high normal stress (660 MPa), to cover the range of normal stresses occurred in the cold expansion process. A full quadratic response surface model was drawn for the friction coefficient's nonlinear relationship between the mandrel and the lubricated sleeve, depending on the normal stresses. The variable friction model was verified with 3-dimensional friction test finite-element (FE) simulations. This FE modeling validates the variable friction model to predict the pulling forces with a sound agreement between the estimated and experimentally obtained values. We conducted split-sleeve cold expansion experiments to obtain the pulling force profile. Two 3-dimensional (3D) FE numerical analyses of the same split-sleeve cold expansion process were conducted using the variable friction model and a constant frictional coefficient of 0.05. The pulling force profiles from the FE modeling with the variable friction model closely align with those from the experiments to show the four distinct regions.

Enhanced salt stress tolerance in plants without growth penalty through increased photosynthesis activity by plastocyanin from Antarctic moss.

Salinity poses a significant challenge to plant growth and crop productivity by adversely affecting crucial processes, including photosynthesis. Efforts to enhance abiotic stress tolerance in crops have been hindered by the trade-off effect, where increased stress resistance is accompanied by growth reduction. In this study, we identified and characterized a plastocyanin gene (PaPC) from the Antarctic moss Polytrichastrum alpinum, which enhanced photosynthesis and salt stress tolerance in Arabidopsis thaliana without compromising growth. While there were no differences in growth and salt tolerance between the wild type and Arabidopsis plastocyanin genes (AtPC1 and AtPC2)-overexpressing plants, PaPC-overexpressing plants demonstrated superior photosynthetic efficiency, increased biomass, and enhanced salt tolerance. Similarly, PaPC-overexpressing rice plants exhibited improved yield potential and photosynthetic efficiency under both normal and salt stress conditions. Key amino acid residues in PaPC responsible for this enhanced functionality were identified, and their substitution into AtPC2 conferred improved photosynthetic performance and stress tolerance in Arabidopsis, tobacco, and tomato. These findings not only highlight the potential of extremophiles as valuable genetic resources but also suggest a photosynthesis-based strategy for developing stress-resilient crops without a growth penalty.