NaCl Conditions Research Articles

Regulation of Catalase Expression and Activity by DhHog1 in the Halotolerant Yeast Debaryomyces hansenii Under Saline and Oxidative Conditions

Efficient transcriptional regulation of the stress response is critical for microorganism survival. In yeast, stress-related gene expression, particularly for antioxidant enzymes like catalases, mitigates reactive oxygen species such as hydrogen peroxide (H2O2), preventing cell damage. The halotolerant yeast Debaryomyces hansenii shows oxidative stress tolerance, largely due to high catalase activity from DhCTA and DhCTT genes. This study evaluates D. hansenii’s response to oxidative stress caused by H2O2 under saline conditions, focusing on cell viability, gene expression, and catalase activity. Chromatin organization in the promoter of DhCTA and DhCTT was analyzed, revealing low nucleosome occupancy in promoter regions, correlating with active gene expression. Stress-related motifs for transcription factors like Msn2/4 and Sko1 were found, suggesting regulation by the DhHog1 MAP kinase. Analysis of a Dhhog1Δ mutant showed DhHog1’s role in DhCTA expression under H2O2 or NaCl conditions. These findings highlight DhHog1’s critical role in regulating the stress response in D. hansenii, offering insights for enhancing stress tolerance in halotolerant yeasts, particularly for industrial applications in saline wastewater management.

HIP is involved in NaCl and endoplasmic reticulum stress resistance in Arabidopsis

Heat shock protein 70 (HSP70)-interacting proteins (HIPs) have been studied in animals. HIPs perform diverse cellular functions, ranging from alleviating stress to suppressing the formation of insoluble protein, but how their orthologs function in plants is less known. This study shows that Arabidopsis HIP is a cytosolic and nuclear protein associated with HSP70. The hip mutants showed compromised tolerance to NaCl and endoplasmic reticulum (ER) stress, although they grew normally under standard growth conditions. Furthermore, hip mutants presented a decreased HSP70 level compared with the wild type under NaCl and ER stress conditions. These findings suggest the involvement of HIP in NaCl and ER stress tolerance.

Comparative kinetics and enhanced desalination efficiency of hydrate-based desalination using HFC-125a, HFC-134a, and HFC-152a through hydrate pelletization and induced melting

The present study demonstrates the feasibility of gas hydrate technology for effective desalination of salt water without requiring pre- or post-treatment. The research highlights two main aspects: the thermodynamic and comparative kinetic properties of hydrofluorocarbon (HFC) gases, and the novel concept of hydrate pelletization enhanced by an induced pellet melting procedure. The thermodynamic viability of HFC gases such as HFC-125a, HFC-134a, and HFC-152a for hydrate formation in both saline and non-saline conditions is underscored. For the first time, a comparative analysis of the gas uptake kinetics for these three gases is presented under 0, 3.5, and 8.0 wt% NaCl conditions. Results indicate that HFC-134a and HFC-152a exhibit rapid gas uptake kinetics, while HFC-125a shows sluggish kinetics, attributed to the effective pressure driving force and subcooling temperature. Regardless of the guest gas, the chosen experimental conditions achieved salt removal efficiency of ~70 % in 3.5 wt% NaCl and ~ 75 % in 8.0 wt% NaCl. The novel induced hydrate pellet melting approach significantly improved salt removal efficiency, exhibiting a nonlinear behavior where the rate of salt removal efficiency increases asymptotically as more hydrate melts. New insights into salt distribution within the hydrate pellet reveal that the core contains higher salinity, than the outer layer.

A novel stepwise salinity acclimation method to improve the survival of freshwater microalgae Haematococcus lacustris in seawater salinity.

Freshwater microalga Haematococcus lacustris rich in astaxanthin, as a supplemental live diet can directly supply natural astaxanthin to the aquaculture organisms, except marine aquaculture organisms, since H. lacustris cannot tolerate seawater salinity. The objective of the present study is to provide a salinity acclimation method that allows H. lacustris to survive and accumulate astaxanthin with the aim of developing a novel supplemental live diet for marine aquaculture organisms. H. lacustris cultured in freshwater was subjected to different stepwise salinity acclimation processes (two-, three-, and four-shift). As the controls, H. lacustris was exposed to five constant salinities conditions (0, 0.05, 0.075, 0.3, and 0.6M NaCl, respectively). Among the controls, almost all cells in the 0.3M and 0.6M NaCl conditions died immediately. In contrast, H. lacustris in the stepwise salinity acclimation processes survived in 0.6M NaCl (equivalent to seawater salinity of 35 psu), showing the highest living-cell proportion (50.0%) and astaxanthin yield (0.72mg·L-1) in the four-shift. The present study first demonstrated that H. lacustris tolerated seawater salinity through a stepwise acclimation process, proving a new strategy to supply live microalgal diets rich in natural astaxanthin for marine aquaculture.

Rootstock Effects on Tomato Fruit Composition and Pollinator Preferences in Tomato

Food security is threatened by climate change and associated abiotic stresses that affect the flowering stage and the biochemistry of flowers and fruits. In tomato, managed insect pollination and grafting elite tomato varieties onto robust rootstocks are widely practiced commercially to enhance tomato crop profitability, particularly under suboptimal conditions. However, little is known about rootstock–pollinator interactions and their impact on the chemical composition of fruit. In this study, a commercial tomato F1 hybrid (Solanum lycopersicum L.) was self-grafted and grafted onto a set of experimental rootstocks and cultivated under optimal and saline (75 mM NaCl) conditions in the presence of managed bumblebee pollinators (Bombus terrestris). The number of visits (VN) and total visiting time (TVT) by pollinators to different grafted plants were monitored through an RFID (radio-frequency identification) tracking system, while targeted metabolites (hormones, sugars, and organic and amino acids) and mineral composition were analyzed in the fruit juice by UHPLC-MS and ICP-OES, respectively. Pollinator foraging decisions were influenced by the rootstocks genotype and salinity treatment. Experimental rootstocks predominantly increased pollinator attraction compared to the self-grafted variety. Interestingly, the pollinator parameters were positively associated with the concentration of abscisic acid, salicylic acid, malate and fumarate, and tyrosine in salinized fruits. Moreover, a high accumulation of sodium was detected in the fruits of the plants most visited by pollinators, while rootstock genotype-specific responses were found for nitrogen and potassium concentrations. In addition to the known effect on yield, these findings underscore the synergic interactions between rootstocks, pollinators, and environmental stressors on tomato fruit composition.

The crosstalk interaction of ethylene, gibberellins, and arbuscular mycorrhiza improves growth in salinized tomato plants by modulating the hormonal balance

Ethylene (ET) and gibberellins (GAs) play key roles in controlling the biotic and abiotic interactions between plants and environment. To gain insights about the role of ET and GAs interactions in the mycorrization and response to salinity of tomato (Solanum lycopersicum L.) plants, the ET-insensitive (Never-ripe, Nr), and the ET-overproducer (Epinastic, Epi) mutants and their wild type cv. Micro-Tom (MT), were inoculated or not with the arbuscular mycorrhizal fungi (AMF) Rhizophagus irregularis and exposed to control (0 mM NaCl) and salinity (100 mM NaCl) conditions, with and without gibberellic acid (10−6 M GA3) application during four weeks. Exogenous GA3 enhanced plant growth irrespective of the genotype, AMF, and salinity conditions, while an additional effect on growth by AMF was only found in the ET-overproducer (Epi) mutant under control and salinity conditions. Epi almost doubled the AMF colonization level under both conditions but was the most affected by salinity and GA3 application compared to MT and Nr. In contrast, Nr registered the lowest AMF colonization level, but GA3 produced a positive effect, particularly under salinity, with the highest leaf growth recovery. Foliar GA3 application increased the endogenous concentration of GA1, GA3, and total GAs, more intensively in AMF-Epi plants, where induced levels of the ET-precursor ACC were also found. Interestingly, GA4 which is associated with AMF colonization, registered the strongest genotype x GA x AMF × salinity interactions. The different growth responses in relation to those interactions are discussed.

Operando facet control of hydrophobic iron nitride nano-coral for surface protection via field-modulated plasma strategy

A facile facet reconfiguration has been considered as an essential issue for nitride coating in promoting surface protection behaviour. Compared to physical-chemical methods to achieve heterogeneous coating, plasma nitridation strategy is regarded as a favourable technique to in-situ deliver nitride protecting layer, but it is difficult to precisely control surface framework through plasma technique due to complicated interaction environment. To simply achieve nitride coating with favourable surface protection behaviour, we design a novel auxiliary insulator-confined plasma system to directly achieve hydrophobic iron nitride nano-coral (hFeNC) with desirable corrosion- and wear-resistant properties by controlling surface heating process during plasma nitridation. The resultant hFeNC nano-framework delivers corrosion rate of 1.2 mpy, 4- and 9-times lower than that of solid iron nitride film (sFeN) via normal plasma and initial Fe in NaCl condition, respectively. Operando plasma diagnostics along with numerical simulation further confirm the effect of surface heating on typical plasma parameters as well as the iron nitride nano-frameworks, indicating surface heating as the key factor responsible for the favourable surface protection coating.

Engineering of protein glutaminase for highly efficient modification of fish myofibrillar protein through structure-based and computational-aided strategy

Protein glutaminase (PG; EC 3.5.1.44) is a class of food-grade enzyme with the potential to significantly improve protein functionality. However, its low catalytic activity and stability greatly hindered industrial application. In this study, we employed structural-based engineering and computational-aided design strategies to target the engineering of protein glutaminase PG5, which led to the development of a combinatorial mutant, MT8, exhibiting a specific activity of 31.1 U/mg and a half-life of 216.2 min at 55 °C. The results indicated that the flexible region in MT8 shifted from the C-terminus to the N-terminus, with increased N-terminal flexibility positively correlating with its catalytic activity. Additionally, MT8 notably boosted fish myofibrillar proteins (MPs) solubility under the absence of NaCl conditions and enhanced their foaming and emulsifying properties. Key residues like Asp31, Ser72, Asn121, Asp471, and Glu485 were crucial for maintaining PG5-myosin interaction, with Ser72 and Asn121 making significant energy contributions.

Physiological characteristics and transcriptomic analysis of response patterns of Gynura divaricata (L.) DC. cultured in vitro under NaCl stress

Soil salinity, a major environmental stress, restricts agricultural production worldwide. Gynura divaricata (L.) DC. is widely cultivated on tropical islands in China and has both edible and medicinal value. NaCl stress and growth indicators, antioxidant enzyme activity, as well as MDA, proline, and soluble sugar content, were determined. Based on the transcriptomic data of tissue-cultured G. divaricata plantlets grown in control (0 mM NaCl) and salt stress (50 and 200 mM NaCl) conditions, gene expression patterns were examined. KEGG enrichment analysis of differentially expressed genes indicated significant enrichment of plant hormone signaling, MAPK signaling, and starch and sucrose metabolism pathways. These findings allowed key biological pathways and salt stress-responsive genes to be identified, thus providing a molecular basis for breeding salt-tolerant G. divaricata varieties. This transcriptomic analysis revealed a complex tolerance mechanism of G. divaricata in response to NaCl, laying a foundation for screening and cloning key genes related to NaCl tolerance and studying their interactions. These findings would allow the molecular basis of NaCl tolerance to be explored, with the aim of breeding NaCl-tolerant varieties.

Characterization of susceptibility patterns and adaptability of the newly emerged Candida auris.

The emergence of Candida auris has caused a major concern in the public health worldwide. This novel fungus is characterized by its multidrug resistance profile, ability to thrive in harsh and stressful conditions, as well as high temperatures and salt concentrations, persistence on hospital surfaces, causing nosocomial infections and outbreaks, and unique fitness properties. Here, we study the antifungal susceptibility patterns, thermotolerance, and halotolerance of 15 putative C. auris clinical isolates from Inkosi Albert Academic Hospital, Durban, South Africa. Five of the C. auris isolates showed resistance to all three antifungals (fluconazole, amphotericin B, and micafungin) and were selected for characterization of their adaptability mechanisms. Four of the tested multidrug-resistant C. auris isolates (C. auris strain F25, C. auris strain F276, C. auris F283, and C. auris M153) showed good growth when exposed to high temperature (42°C) and salinity (10% NaCl) conditions whereas one isolate (C. auris F65) showed moderate growth under these conditions. Candida parapsilosis showed poor growth whereas C. albicans no growth under these conditions. The five C. auris strains were positive for all the adaptive features.

Synthesis and Performance Evaluation of High-Temperature-Resistant Extreme-Pressure Lubricants for a Water-Based Drilling Fluid Gel System.

Addressing the high friction and torque challenges encountered in drilling processes for high-displacement wells, horizontal wells, and directional wells, we successfully synthesized OAG, a high-temperature and high-salinity drilling fluid lubricant, using materials such as oleic acid and glycerol. OAG was characterized through Fourier-transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA). The research findings demonstrate the excellent lubricating performance of OAG under high-temperature and high-salinity conditions. After adding 1.0% OAG to a 4% freshwater-based slurry, the adhesion coefficient of the mud cake decreased to 0.0437, and at a dosage of 1.5%, the lubrication coefficient was 0.032, resulting in a reduction rate of 94.1% in the lubrication coefficient. After heating at 200 °C for 16 h, the reduction rate of the lubrication coefficient reached 93.6%. Even under 35% NaCl conditions, the reduction rate of the lubrication coefficient remained at 80.3%, indicating excellent lubrication retention performance. The lubricant OAG exhibits good compatibility with high-density drilling fluid gel systems, maintaining their rheological properties after heating at 200 °C and reducing filtration loss. The lubrication mechanism analysis indicates that OAG can effectively adsorb onto the surface of N80 steel sheets. The contact angle of the steel sheets increased from 41.9° to 83.3° before and after hot rolling, indicating a significant enhancement in hydrophobicity. This enhancement is primarily attributed to the formation of an extreme-pressure lubricating film through chemical reactions of OAG on the metal surface. Consequently, this film markedly reduces the friction between the drilling tools and the wellbore rocks, thereby enhancing lubrication performance and providing valuable guidance for constructing high-density water-based drilling fluid gel systems.

A CAM-Related NF-YB Transcription Factor Enhances Multiple Abiotic Stress Tolerance in Arabidopsis.

Abiotic stresses often occur simultaneously, and the tolerance mechanisms of plants to combined multiple abiotic stresses remain poorly studied. Extremophytes, adapted to abiotic stressors, might possess stress-adaptive or -responsive regulators that could enhance multiple abiotic stress resistance in crop plants. We identified an NF-YB transcription factor (TF) from the heat-tolerant obligate Crassulacean acid metabolism (CAM) plant, Kalanchoe fedtschenkoi, as a potential regulator of multiple abiotic stresses. The KfNF-YB3 gene was overexpressed in Arabidopsis to determine its role in multiple abiotic stress responses. Transgenic lines exhibited accelerated flowering time, increased biomass, larger rosette size, higher seed yield, and more leaves. Transgenic lines had higher germination rates under combined NaCl, osmotic, and water-deficit stress treatments compared to control plants. They also showed enhanced root growth and survival under simultaneous NaCl, osmotic, water-deficit, and heat stress conditions in vitro. Interestingly, potted transgenic lines had higher survival rates, yield, and biomass under simultaneous heat, water-deficit, and light stresses compared to control plants. Altogether, these results provide initial insights into the functions of a CAM-related TF and its potential roles in regulating multiple abiotic stress responses. The CAM abiotic stress-responsive TF-based approach appears to be an ideal strategy to enhance multi-stress resilience in crop plants.

NaCl Modifies Biochemical Traits in Bacterial Endophytes Isolated from Halophytes: Towards Salinity Stress Mitigation Using Consortia.

Bacterial endophytes (120) were isolated from six halophytes (Distichlis spicata, Cynodon dactylon, Eragrostis obtusiflora, Suaeda torreyana, Kochia scoparia, and Baccharis salicifolia). These halophiles were molecularly identified and characterized with or without NaCl conditions. Characterization was based on tests such as indole acetic acid (IAA), exopolysaccharides (EPS), and siderophores (SID) production; solubilization of phosphate (P), potassium (K), zinc (Zn), and manganese (Mn); mineralization of phytate; enzymatic activity (acid and alkaline phosphatase, phytases, xylanases, and chitinases) and the mineralization/solubilization mechanisms involved (organic acids and sugars). Moreover, compatibility among bacteria was assessed. Eleven halophiles were characterized as highly tolerant to NaCl (2.5 M). The bacteria isolated were all different from each other. Two belonged to Bacillus velezensis and one to B. pumilus while the rest of bacteria were identified up to the genus level as belonging to Bacillus, Halobacillus, Halomonas, Pseudomonas, Nesterenkonia, and three strains of Oceanobacillus. The biochemical responses of nutrient solubilization and enzymatic activity were different between bacteria and were influenced by the presence of NaCl. Organic acids were involved in P mineralization and nutrient solubilization. Tartaric acid was common in the solubilization of P, Zn, and K. Maleic and vanillic acid were only detected in Zn and K solubilization, respectively. Furthermore, sugars appeared to be involved in the solubilization of nutrients; fructose was detected in the solubilization tests. Therefore, these biochemical bacterial characteristics should be corroborated in vivo and tested as a consortium to mitigate saline stress in glycophytes under a global climate change scheme that threatens to exacerbate soil salinity.

Selected Beneficial Microbes Alleviate Salinity Stress in Hydroponic Lettuce and Pak Choi

Hydroponics is widely used in greenhouse and vertical farming production because these facilities can precisely control environmental conditions such as lighting, temperature, and vapor pressure deficit. However, the fertilizer solutions have a short life span, and they often do not have adequate microbial populations to enhance plant growth. Previous studies have shown the potential of beneficial microbes to promote plant production and alleviate abiotic and biotic stressors in the field, and studies on their use in controlled environments such as greenhouses and vertical farms are limited in the literature. In this study, we selected several plant growth promoting microbes (PGPMs) and tested their effects on alleviating salinity stress in ‘Rex’ lettuce (Lactuca sativa) and ‘Red Pac’ pak choi (Brassica chinensis) grown in deep water culture hydroponics. Our goal was to use one stressor, salinity, that induces profound symptoms in plant morphology. A three-cycle study was conducted using five PGPMs [Bacillus, Glomus, Lactobacillus, Trichoderma, and Bacillus/Pseudomonas/Trichoderma (B/P/T) mix] and two salinity levels [no salinity and salinity treatment, with 120 mM, 40 mM, and 80 mM sodium chloride (NaCl) solution used for the first, second, and third cycles, respectively]. We measured the effects of PGPMs and salinity on plant growth and quality and the solution pH and electrical conductivity (EC). Salinity stress decreased lettuce and pak choi leaf area and shoot fresh weight and increased plant leaf chlorophyll and anthocyanin contents with increased solution EC. Under high-salinity stress (120 mM NaCl), the addition of Trichoderma reduced pak choi leaf area and fresh weight but increased solution pH, whereas under low salinity stress (40 mM NaCl), Trichoderma increased pak choi leaf chlorophyll content. Under moderate-salinity stress (80 mM NaCl) condition, the addition of Glomus sp. increased lettuce fresh weight and leaf area, and B/P/T mix increased pak choi leaf area. In conclusion, using the selected PGPMs in low to moderate-salinity stress could increase lettuce and pak choi growth and quality parameters. These results have some practical applications in the future when more saline water is used for production.

Effects of basic amino acids on heterocyclic amines and quality characteristics of fried beef patties at low NaCl level

The impact of basic amino acids (Lysine, Arginine, Histidine) on the formation of total heterocyclic amines (HAs) was investigated in fried beef patties at 1% NaCl level. Different levels of basic amino acids (0.1%, 0.5%, 1%) significantly inhibited the formation of the total and individual HAs at 1% NaCl, and the inhibitory effect was more effective than 3% NaCl (6.19 ng/g, 26.93% inhibition) (P < 0.05). Lys at 1% reduced total HAs the most (2.46 ng/g, 70.88% inhibition), followed by 1% His (2.79 ng/g, 67.03% inhibition) and 1% Arg (3.43 ng/g, 59.51% inhibition). Compared to the 3% NaCl, the quality characteristics (moisture content, frying loss, texture profile, and color) of the fried beef patties were significantly improved when basic amino acids were added at 1% NaCl (P < 0.05). The lipid oxidation of fried beef patties was significantly inhibited by 1% Arg and 1% Lys at 1% NaCl level (P < 0.05). The results indicated that basic amino acids could inhibit the formation of total HAs while maintaining the quality of meat products at low NaCl condition.

CD4+ T Cell Effector Status Is Dependent on Aryl Hydrocarbon Receptor Activation during High Salt Diet

Recent studies suggest that patients with hypertension and individuals that consume a HSD are depleted of numerous tryptophan-derived indoles and other AHR-binding metabolites that are key in intestinal CD4+ T cell homeostasis. Thus, the inappropriate immunologic response by CD4+ T cells, and their role in hypertension, may be due in part to loss of AHR activation. Therefore, we hypothesized that AHR activation contributes to maintaining effector T cell status in salt-sensitive mice. To examine the influence of a representative homeostatic or proinflammatory environment and the subsequent response to salt, we cultured naïve CD4+ T cells under homeostatic cytokine or pathogenic cytokine conditions and exposed the cultures to increased NaCl conditions with or without the AHR-activating metabolite, FICZ (6-Formylindolo(3,2-b)-carbazole). TH17 cells cultured under homeostatic high salt conditions were depressed with a concomitant increase in response to FICZ. In contrast, TH17 cells cultured under pathogenic high salt conditions had augmented IL-17A-expressing cells without a response to AHR activation. These data suggest that excess salt is disrupting the ability to induce IL-17A and increasing AHR activity overcomes this disruption to promote IL-17A, without expansion of the pathogenic TH17 pool, and this observation was specific to non-pathogenic microenvironments (homeostatic TH17: media: 11±0.6%, +NaCl: 4.9±0.3%*, +NaCl/FICZ: 9.9±0.8%, of CD4; pathogenic TH17: media: 1.0±0.2%, +NaCl: 2.2±0.2%*, +NaCl/FICZ: 2.2±0.2%*, *vs respective media, n=8/group). Given these data, we then fed salt-sensitive mice (nitric oxide synthase inhibition) a HSD or a HSD supplemented with the AHR agonist indole-3-carbinol (I3C) and examined Peyer’s patches, a lymphoid tissue in close proximity to intestinal lumen contents enriched with salt and the I3C-metabolites and noted expansion of non-pathogenic TH17 cells. In conclusion, increasing AHR ligand availability through supplementing I3C may provide a gut-centric experimental approach in targeting experimental salt-sensitivity as it relates to immunologic disturbances. F31HL151264. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Understanding the influence of environmental conditions on the low cycle fatigue behaviour of high strength low alloy (HSLA) steel under air and corrosive (3.5% NaCl) conditions

Offshore structures which are made up of high-strength low alloy (HSLA) steel experience fatigue load due to sea waves and corrosion. In the present work, the influence of environmental conditions (air and 3.5 % NaCl solution) on the strain-controlled fatigue life of High Strength Low Alloy (HSLA) steel has been determined. Low cycle fatigue experiments were conducted on HSLA steel specimens of 12 mm diameter which were prepared parallel to the rolling direction. The strain amplitude was varied in the range of 0.4 to 0.7 % for a constant test frequency of 0.3 Hz. For all the total strain amplitudes (Δεt/2), a significant reduction in fatigue life was observed while testing the specimens under the presence of 3.5 % NaCl solution compared to the air environment. Microscopic investigation indicates that rigorous grain boundary oxidation has happened, and it has created the grain boundary cracking and several sites for fatigue crack initiation and propagation. The presence of corrosive compounds (Fe2O3, FeOOH) was also confirmed by the X-ray diffraction patterns. In addition, mixed modes (transannular and intergranular) of fractures were observed due to the presence of 3.5 % NaCl solution.

Stressing out-carp edema virus induces stress and modulates immune response in common carp.

Carp edema virus (CEV) is a fish poxvirus that primarily infects the gills of common carp. CEV causes koi sleepy disease (KSD), which is highly contagious and can result in mortality of up to 100%. In the present study, we analyzed the stress and immune responses during KSD in two strains of common carp with different resistance to CEV: susceptible koi and resistant Amur sazan. Experiments were performed at two temperatures: 12°C and 18°C. In the case of koi carp, we also analyzed the effect of supplementation of 0.6% NaCl into tank water, which prevents mortality of the CEV-infected fish (salt rescue model). We found that CEV-infected koi kept at 18°C had the highest viral load, which correlated with the most severe histopathological changes in the gills. CEV infection resulted in the activation of stress response reflected by the upregulated expression of genes involved in stress response in the stress axis organs and increased levels of cortisol and glucose in the blood plasma. These changes were the most pronounced in CEV-infected koi kept at 18°C. At both temperatures, the activation of antiviral immune response was observed in koi kept under freshwater and NaCl conditions upon CEV infection. Interestingly, a clear downregulation of the expression of adaptive immune genes was observed in CEV-infected koi kept under freshwater at 18°C. CEV induces a stress response and modulates adaptive immune response in koi, and this is correlated with the level of viral load and disease development.

Variations of salt stress responses and functional identification of TgPYR1-like8 in Tulipa gesneriana

Tulip cut flowers are mainly produced through hydroponic cultivation. The accumulation of nutrient substances in hydroponic solution generally resulted in ion stress and osmotic stress, which in turn affected the growth and ornamental characteristics of tulip plants. This study aimed to evaluate and compare the salt stress sensitivities of tulip cultivated varieties. The results indicated that most of tulip cultivars showed relatively high sensitivity to low concentrations of NaCl treatment, while the root growth and floral stalk elongation were significantly inhibited by 15 mM NaCl and flowering opening was completely prevented under 75 mM NaCl conditions. Salt stress caused differential accumulations of osmotic regulators including proline, soluble sugars and ions concentrations between two contrasting varieties. We further identified the function of TgPYR1-like8 which showed differential expression patterns among tulip cultivars and displayed the most expression abundance in flower petals. TgPYR1-like8 over expressed Arabidopsis lines showed hypersensitivity to salt treatment during seed germination and young seedlings growth when compared with wild-type plant. Transient silencing of endogenous TgPYR1-like8 in tulip petal discs decreased salt sensitivity and delayed salt-induced petal senescence. These findings provide evidences for revealing the function of TgPYR1-like8 in tulip salt stress responses and more clues on how to improve the hydroponic cultivation of different tulip varieties.

Enhancing bioremediation potential of microalgae Chlorella vulgaris and Scenedesmus acutus by NaCl for pyrene degradation.

Microalgae are increasingly recognized as promising organisms for bioremediation of organic pollutants. This study investigates the potential of enhancing the bioremediation efficiency of pyrene (PYR), a polycyclic aromatic hydrocarbon (PAH), through NaCl induced physiological and biochemical alterations in two microalgae species, Chlorella vulgaris and Scenedesmus acutus. Our findings reveal significant improvement in PYR removal when these microalgae were cultivated in the presence of 0.1% NaCl where PYR removal increased from 54 to 74% for C. vulgaris and from 26 to 75% for S. acutus. However, it was observed that NaCl induced stress had varying effects on the two species. While C. vulgaris exhibited increased PYR removal, it experienced reduced growth and biomass production, as well as lower photosynthetic efficiency when exposed to PYR and PYR + NaCl. In contrast, S. acutus displayed better growth and biomass accumulation under PYR + NaCl conditions, making it a more efficient candidate for enhancing PYR bioremediation in the presence of NaCl. In addition to assessing growth and biochemical content, we also investigated stress biomarkers, such as lipid peroxidation, polyphenol and proline contents. These findings suggest that S. acutus holds promise as an alternative microalgae species for PYR removal in the presence of NaCl, offering potential advantages in terms of bioremediation efficiency and ecological sustainability. This study highlights the importance of understanding the physiological and biochemical responses of microalgae to environmental stressors, which can be harnessed to optimize bioremediation strategies for the removal of organic pollutants like PYR.