RÉSUMÉ
MAIN CONCLUSION: The genetic diversity in tetraploid wheat provides a genetic pool for improving wheat productivity and environmental resilience. The tetraploid wheat had strong N uptake, translocation, and assimilation capacity under N deficit stress, thus alleviating growth inhibition and plant N loss to maintain healthy development and adapt to environments with low N inputs. Tetraploid wheat with a rich genetic variability provides an indispensable genetic pool for improving wheat yield. Mining the physiological mechanisms of tetraploid wheat in response to nitrogen (N) deficit stress is important for low-N-tolerant wheat breeding. In this study, we selected emmer wheat (Kronos, tetraploid), Yangmai 25 (YM25, hexaploid), and Chinese spring (CS, hexaploid) as materials. We investigated the differences in the response of root morphology, leaf and root N accumulation, N uptake, translocation, and assimilation-related enzymes and gene expression in wheat seedlings of different ploidy under N deficit stress through hydroponic experiments. The tetraploid wheat (Kronos) had stronger adaptability to N deficit stress than the hexaploid wheats (YM25, CS). Kronos had better root growth under low N stress, expanding the N uptake area and enhancing N uptake to maintain higher NO3- and soluble protein contents. Kronos exhibited high TaNRT1.1, TaNRT2.1, and TaNRT2.2 expression in roots, which promoted NO3- uptake, and high TaNRT1.5 and TaNRT1.8 expression in roots and leaves enhanced NO3- translocation to the aboveground. NR and GS activity in roots and leaves of Kronos was higher by increasing the expression of TANIA2, TAGS1, and TAGS2, which enhanced the reduction and assimilation of NO3- as well as the re-assimilation of photorespiratory-released NH4+. Overall, Kronos had strong N uptake, translocation, and assimilation capacity under N deficit stress, alleviating growth inhibition and plant N loss and thus maintaining a healthy development. This study reveals the physiological mechanisms of tetraploid wheat that improve nitrogen uptake and assimilation adaptation under low N stress, which will provide indispensable germplasm resources for elite low-N-tolerant wheat improvement and breeding.
Sujet(s)
Azote , Racines de plante , Stress physiologique , Tétraploïdie , Triticum , Triticum/génétique , Triticum/métabolisme , Triticum/croissance et développement , Triticum/physiologie , Azote/métabolisme , Stress physiologique/génétique , Racines de plante/génétique , Racines de plante/croissance et développement , Racines de plante/métabolisme , Racines de plante/physiologie , Feuilles de plante/génétique , Feuilles de plante/métabolisme , Feuilles de plante/croissance et développement , Feuilles de plante/physiologie , Adaptation physiologique/génétique , Plant/génétique , Plant/croissance et développement , Plant/physiologie , Plant/métabolisme , Régulation de l'expression des gènes végétauxRÉSUMÉ
Although tetraploid wheat has rich genetic variability for cultivar improvement, its physiological mechanisms associated with photosynthetic productivity and resilience under nitrogen (N) deficit stress have not been investigated. In this study, we selected emmer wheat (Kronos, tetraploid), Yangmai 25 (YM25, hexaploid), and Chinese Spring (CS, hexaploid) as materials and investigated the differences in net photosynthetic rate (Pn), carboxylation capacity, electron transfer capacity, photosynthetic product output, and photosynthetic N allocation under normal N (CK) and low N (LN) through hydroponic experiments. Tetraploid emmer wheat (Kronos) had a stronger photosynthetic capacity than hexaploid wheat (YM25, CS) under low N stress, which mainly associated with the higher degree of PSII opening, electron transfer rate, Rubisco content and activity, ATP/ADP ratio, Rubisco activase (Rca) activity and Rubisco activation state, and more leaves N allocation to the photosynthetic apparatus, especially the proportion of N allocation to carboxylation under low N stress. Moreover, Kronos reduced the feedback inhibition of photosynthesis by sucrose accumulation through higher sucrose phosphate synthetase (SPS) activity and triose phosphate utilization rate (VTPU). Overall, Kronos could allocate more N to the photosynthetic components to improve Rubisco content and activity to maintain photosynthetic capacity under low N stress while enhancing triose phosphate output to reduce feedback inhibition of photosynthesis. This study reveals the physiological mechanisms of emmer wheat that maintain the photosynthetic capacity under low N stress, which will provide indispensable germplasm resources for elite low-N-tolerant wheat improvement and breeding.
Sujet(s)
Azote , Photosynthèse , Ribulose bisphosphate carboxylase , Triticum , Photosynthèse/physiologie , Triticum/physiologie , Triticum/génétique , Triticum/métabolisme , Azote/métabolisme , Ribulose bisphosphate carboxylase/métabolisme , Stress physiologique , Feuilles de plante/physiologie , Feuilles de plante/métabolisme , Adaptation physiologique , Protéines végétales/métabolisme , Protéines végétales/génétique , Chlorophylle/métabolisme , Complexe protéique du photosystème II/métabolisme , Glucosyltransferases/métabolisme , Glucosyltransferases/génétiqueRÉSUMÉ
MAIN CONCLUSION: Early-stage low nitrogen priming promotes root growth and delays leaf senescence through gene expression, enhancing nitrogen absorption and assimilation in wheat seedlings, thereby alleviating growth inhibition under nitrogen deficit stress and supporting normal seedling development. Verifying the strategies to reduce the amount of nitrogen (N) fertilizer while maintaining high crop yields is important for improving crop N use efficiency (NUE) and protecting the environment. To determine whether low N (LN) priming (LNP) can alleviate the impact of N-deficit stress on the growth of wheat seedlings and improve their tolerance to N-deficit stress, we conducted hydroponic experiments using two wheat cultivars, Yangmai 158 (YM158, LN tolerant) and Zaoyangmai (ZYM, LN sensitive) to study the effects of LNP on wheat seedlings under N-deficit stress. N-deficit stress decreased the plant dry weight, leaf area, and leaf N content (LNC), while LNP could significantly reduce this reduction. Distinct sensitivities to N-deficit stress were observed between the wheat cultivars, with ZYM showing an early decrease in leaf N content compared to YM158, which exhibited a late-stage reduction. LNP promoted root growth, expanded N uptake area, and upregulated the expression of TaNRT1.1, TaNRT2.1, and TaNRT2.2 in wheat seedlings, suggesting that LNP can enhance root N uptake capacity to increase N accumulation in plants. In addition, LNP improved the activity of glutamine synthase (GS) to enhance the capacity of N assimilation of plants. The relative expression of TaGS1 in the lower leaves of priming and stress (PS) was lower than that of no priming and stress (NS) after LNP, indicating that the rate of N transfer from the lower leaves to the upper leaves became slower after LNP, which alleviated the senescence of the lower leaves. The relative expression of TaGS2 was significantly increased, which might be related to the enhanced photorespiratory ammonia assimilation capacity after LNP, which reduced the N loss and maintained higher LNC. Therefore, LNP in the early stage can improve the N absorption and assimilation ability and maintain the normal N supply to alleviate the inhibition of N-deficit stress in wheat seedlings.
Sujet(s)
Plant , Tétrazoles , Thiazoles , Triticum , Triticum/génétique , Azote/métabolisme , Plantes/métabolismeRÉSUMÉ
Source-sink relationships influence photosynthesis. So far, the limiting factors for photosynthesis of wheat cultivars with different source-sink relationships have not been determined. We aimed to determine the variation patterns of photosynthetic characteristics of wheat cultivars with different source-sink relationships. In this study, two wheat cultivars with different source-sink relationships were selected for photosynthetic physiological analyses. The results showed that YM25 (source-limited cultivar) had higher photosynthetic efficiency compared to YM1 (sink-limited cultivar). This is mainly due to a stronger photochemical efficiency, electron transfer capacity, and Rubisco carboxylation capacity of YM25. YM25 accumulated less soluble carbohydrates in flag leaves than YM1. This is mainly due to the stronger sucrose synthesis and transport capacity of YM25 by presenting higher sucrose-related enzyme activities and gene expression. A PCA analysis showed that Rubisco was the main factor limiting the photosynthetic capacity of YM25. The soluble sugar accumulation in flag leaves and sink limitation decreased the photosynthetic activity of YM1. Increased N application improved source-sink relationships and increased grain yield and source leaf photosynthetic capacity in both two wheat cultivars. Taken together, our findings suggest that Rubisco and sucrose synthesis and translocation are involved in the regulation of photosynthesis of wheat cultivars with different source-sink relationships and that source and sink limitation effects should be considered in photosynthesis.
Sujet(s)
Ribulose bisphosphate carboxylase , Triticum , Triticum/génétique , Photosynthèse , Métabolisme glucidique , SaccharoseRÉSUMÉ
The use of slow-release fertilizers and seed-fertilizers cause localized high-ammonium (NH4 +) environments in agricultural fields, adversely affecting wheat growth and development and delaying its yield. Thus, it is important to investigate the physiological responses of wheat and its tolerance to NH4 + stress to improve the adaptation of wheat to high NH4 + environments. In this study, the physiological mechanisms of ammonium tolerance in wheat (Triticum aestivum) were investigated in depth by comparative analysis of two cultivars: NH4 +-tolerant Xumai25 and NH4 +-sensitive Yangmai20. Cultivation under hydroponic conditions with high NH4 + (5 mM NH4 +, AN) and nitrate (5 mM NO3 -, NN), as control, provided insights into the nuanced responses of both cultivars. Compared to Yangmai20, Xumai25 displayed a comparatively lesser sensitivity to NH4 + stress, as evident by a less pronounced reduction in dry plant biomass and a milder adverse impact on root morphology. Despite similarities in NH4 + efflux and the expression levels of TaAMT1.1 and TaAMT1.2 between the two cultivars, Xumai25 exhibited higher NH4 + influx, while maintaining a lower free NH4 + concentration in the roots. Furthermore, Xumai25 showed a more pronounced increase in the levels of free amino acids, including asparagine, glutamine, and aspartate, suggesting a superior NH4 + assimilation capacity under NH4 + stress compared to Yangmai20. Additionally, the enhanced transcriptional regulation of vacuolar glucose transporter and glucose metabolism under NH4 + stress in Xumai25 contributed to an enhanced carbon skeleton supply, particularly of 2-oxoglutarate and pyruvate. Taken together, our results demonstrate that the NH4 + tolerance of Xumai25 is intricately linked to enhanced glucose metabolism and optimized glucose transport, which contributes to the robust NH4 + assimilation capacity.
RÉSUMÉ
BACKGROUND: There is a need for effective and safe therapies for psoriasis that provide sustained benefits. The aim of this study was to assess the efficacy and safety of tildrakizumab, an anti-interleukin-23p19 monoclonal antibody, for treating moderate-to-severe plaque psoriasis in Chinese patients. METHODS: In this multi-center, double-blind, phase III trial, patients with moderate-to-severe plaque psoriasis were enrolled and randomly assigned (1:1) to receive subcutaneous tildrakizumab 100 mg or placebo at weeks 0 and 4. Patients initially assigned to placebo were switched to receive tildrakizumab at weeks 12, 16, and every 12 weeks thereafter. Patients in the tildrakizumab group continued with tildrakizumab at week 16, and every 12 weeks until week 52. The primary endpoint was the Psoriasis Area and Severity Index (PASI 75) response rate at week 12. RESULTS: At week 12, tildrakizumab demonstrated significantly higher PASI 75 response rates (66.4% [73/110] vs. 12.7% [14/110]; difference, 51.4% [95% confidence interval (CI), 40.72, 62.13]; P <0.001) and Physician's Global Assessment (60.9% [67/110] vs. 10.0% [11/110]; difference, 49.1% [95% CI, 38.64, 59.62]; P <0.001) compared to placebo. PASI 75 response continued to improve over time in both tildrakizumab and placebo-switching to tildrakizumab groups, reaching maximal efficacy after 28 weeks (86.8% [92/106] vs . 82.4% [89/108]) and maintained up to 52 weeks (91.3% [95/104] vs . 87.4% [90/103]). Most treatment-emergent adverse events were mild and not related to tildrakizumab. CONCLUSION: Tildrakizumab demonstrated durable efficacy through week 52 and was well tolerated in Chinese patients with moderate-to-severe plaque psoriasis. TRIAL REGISTRATION: ClinicalTrials.gov , NCT05108766.
Sujet(s)
Anticorps monoclonaux humanisés , Psoriasis , Humains , Psoriasis/traitement médicamenteux , Mâle , Femelle , Adulte d'âge moyen , Anticorps monoclonaux humanisés/usage thérapeutique , Méthode en double aveugle , Adulte , Résultat thérapeutique , Jeune adulte , Sujet âgé , Peuples d'Asie de l'EstRÉSUMÉ
Understanding the physiological mechanism underlying nitrogen levels response to a low red/far-red ratio (R/FR) can provide new insights for optimizing wheat yield potential but has been not well documented. This study focused on the changes in nitrogen levels, nitrogen assimilation and nitrate uptake in wheat plants grown with and without additional far-red light. A low R/FR reduced wheat nitrogen accumulation and grain yield compared with the control. The levels of total nitrogen, free amino acid and ammonium were decreased in leaves but nitrate content was temporarily increased under a low R/FR. The nitrate reductase (NR) activity in leaves was more sensitive to a low R/FR than glutamine synthetase, glutamate synthase, glutamic oxalacetic transaminase and glutamic-pyruvic transaminase. Further analysis showed that a low R/FR had little effect on the NR activation state but reduced the level of NR protein and the expression of encoding gene TaNR1.2. Interestingly, a low R/FR rapidly induced TaPIL5 expression rather than TaHY5 and other members of TaPILs in wheat, suggesting that TaPIL5 was the key transcription factor response to a low R/FR in wheat and might be involved in the downregulation of TaNR1.2 expression. Besides, a low R/FR downregulated the expression of TaNR1.2 in leaves earlier than that of TaNRT1.1/1.2/1.5/1.8 in roots, which highlights the importance of NR and nitrogen assimilation in response to a low R/FR. Our results provide revelatory evidence that restricted nitrate reductase associated with downregulated TaNR1.2 and upregulated TaPIL5 mediate the suppression of nitrogen assimilation under a low R/FR in wheat.
Sujet(s)
Composés d'ammonium , Triticum , Nitrate reductase/génétique , Nitrate reductase/métabolisme , Triticum/métabolisme , Nitrates/métabolisme , Azote/métabolisme , Composés d'ammonium/métabolismeRÉSUMÉ
Psoriasis is one of the common chronic inflammatory skin diseases worldwide. The skin microbiota plays a role in psoriasis through regulating skin homeostasis. However, the studies on the interactions between symbiotic microbial strains and psoriasis are limited. In this study, Staphylococcus strain XSB102 was isolated from the skin of human, which was identified as Staphylococcus warneri using VITEK2 Compact. To reveal the roles of Staphylococcus warneri on psoriasis, XSB102 were applied on the back of imiquimod-induced psoriasis-like dermatitis mice. The results indicated that it exacerbated the psoriasis and significantly increased the thickening of the epidermis. Furthermore, in vitro experiments confirmed that inactivated strain XSB102 could promote the proliferation of human epidermal keratinocytes (HaCaT) cell. However, real-time quantitative PCR and immunofluorescence results suggested that the expression of inflammatory factors such as IL-17a, IL-6, and so on were not significantly increased, while extracellular matrix related factors such as Col6a3 and TGIF2 were significantly increased after XSB102 administration. This study indicates that Staphylococcus warneri XSB102 can exacerbate psoriasis and promote keratinocyte proliferation independently of inflammatory factors, which paves the way for further exploration of the relationship between skin microbiota and psoriasis.
Sujet(s)
Dermatite , Psoriasis , Souris , Humains , Animaux , Imiquimod/effets indésirables , Imiquimod/métabolisme , Psoriasis/induit chimiquement , Psoriasis/métabolisme , Peau , Kératinocytes/métabolisme , Staphylococcus/génétique , Prolifération cellulaire , Dermatite/métabolisme , Modèles animaux de maladie humaine , Souris de lignée BALB C , Protéines de répression/métabolisme , Protéines à homéodomaine/effets indésirables , Protéines à homéodomaine/métabolismeRÉSUMÉ
Phosphorus (P) deficit limits high wheat (Triticum aestivum L.) yields. Breeding low-P-tolerant cultivars is vital for sustainable agriculture and food security, but the low-P adaptation mechanisms are largely not understood. Two wheat cultivars, ND2419 (low-P-tolerant) and ZM366 (low-P-sensitive) were used in this study. They were grown under hydroponic conditions with low-P (0.015 mM) or normal-P (1 mM). Low-P suppressed biomass accumulation and net photosynthetic rate (A) in both cultivars, whereas ND2419 was relatively less suppressed. Intercellular CO2 concentration did not decrease with the decline of stomatal conductance. Additionally, maximum electron transfer rate (Jmax) decreased sooner than maximum carboxylation rate (Vcmax). Results indicate that impeded electron transfer is directly responsible for decreased A. Under low-P, ND2419 exhibited greater PSII functionality (potential activity (Fv/Fo), maximum quantum efficiency (Fv/Fm), photochemical quenching (qL) and non-photochemical quenching (NPQ) required for electron transfer than ZM366, resulting more ATP for Rubisco activation. Furthermore, ND2419 maintained higher chloroplast Pi concentrations by enhancing chloroplast Pi allocation, compared with ZM366. Overall, the low-P-tolerant cultivar sustained electron transfer under low-P by enhancing chloroplast Pi allocation, allowing more ATP synthesis for Rubisco activation, ultimately presenting stronger photosynthesis capacities. The improved chloroplasts Pi allocation may provide new insights into improve low-P tolerance.
Sujet(s)
Ribulose bisphosphate carboxylase , Triticum , Triticum/physiologie , Électrons , Amélioration des plantes , Photosynthèse/physiologie , Chloroplastes , Adénosine triphosphate , Feuilles de plante/physiologieRÉSUMÉ
Interleukin-33ï¼IL-33), is constitutively expressed in the epithelial cells of the skin. It has been reported that IL-33 contributed to the severity of the disease in psoriasis-like mouse models. In the current study, we evaluated the effect of anti-IL-33 antibody (Ab) in imiquimod-induced psoriatic dermatitis in mice. Our observations showed that anti-IL-33 Ab ameliorated the erythema, scaling, epidermal thickness and spleen index. Additionally, we found anti-IL-33 Ab significantly decreased the expression of psoriasis-related cytokines. Moreover, anti-IL-33 Ab significantly reduced Ki-67 positive cells, CD3+CD4+T cells, and CD3+CD8+T cells in the skin lesions. Furthermore, anti-IL-33 Ab treatment down-regulated the expression of phosphorylation of STAT3 and IL-33 in model mouse. These results indicated that the anti-IL-33 Ab alleviated the seriousness of skin lesions, inhibited the activation of the STAT3, lymphocyte infiltration and the secretion of pro-inflammatory cytokines in imiquimod-induced psoriatic dermatitis in mice, suggesting IL-33 may be a therapeutic target for the treatment of psoriasis.
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Dermatite , Psoriasis , Animaux , Souris , Imiquimod/pharmacologie , Interleukine-33/métabolisme , Peau/anatomopathologie , Psoriasis/traitement médicamenteux , Cytokines/métabolisme , Dermatite/anatomopathologie , Souris de lignée BALB C , Modèles animaux de maladie humaineRÉSUMÉ
Efficacy of clinical chemotherapeutic agents depends not only on direct cytostatic and cytotoxic effects but also involves in eliciting (re)activation of tumour immune effects. One way to provoke long-lasting antitumour immunity is coined as immunogenic cell death (ICD), exploiting the host immune system against tumour cells as a "second hit". Although metal-based antitumour complexes hold promise as potential chemotherapeutic agents, ruthenium (Ru)-based ICD inducers remain sparse. Herein, we report a half-sandwich complex Ru(II) bearing aryl-bis(imino) acenaphthene chelating ligand with ICD inducing properties for melanoma inâ vitro and inâ vivo. Complex Ru(II) displays strong anti-proliferative potency and potential cell migration inhibition against melanoma cell lines. Importantly, complex Ru(II) drives the multiple biochemical hallmarks of ICD in melanoma cells, i. e., the elevated expression of calreticulin (CRT), high mobility group box 1 (HMGB1), Hsp70 and secretion of ATP, followed by the decreased expression of phosphorylation of Stat3. In vivo the inhibition of tumour growth in prophylactic tumour vaccination model further confirms that mice with complex Ru(II)-treated dying cells lead to activate adaptive immune responses and anti-tumour immunity by the activation of ICD in melanoma cells. Mechanisms of action studies show that complex Ru(II)-induced ICD could be associated with mitochondrial damage, ER stress and impairment of metabolic status in melanoma cells. We believe that the half-sandwich complex Ru(II) as an ICD inducer in this work will help to design new half-sandwich Ru-based organometallic complexes with immunomodulatory response in melanoma treatments.
Sujet(s)
Antinéoplasiques , Complexes de coordination , Mélanome , Ruthénium , Animaux , Souris , Ruthénium/pharmacologie , Ruthénium/composition chimique , Mort cellulaire immunogène , Antinéoplasiques/pharmacologie , Antinéoplasiques/composition chimique , Complexes de coordination/pharmacologie , Complexes de coordination/composition chimique , Mélanome/traitement médicamenteux , Lignée cellulaire tumoraleRÉSUMÉ
Drought stress is one of the most serious environmental stress factor constraining crop production across the globe. Among cereals, wheat grains are very sensitive to drought as a small degree of stress can affect the enzymatic system. This study aimed to investigate whether nitrogen and pre-anthesis drought priming could enhance the action of major regulatory enzymes involved in starch accumulation and protein synthesis in bread wheat (Triticum aestivum L.). For this purpose, cultivars YM-158 (medium gluten) and YM-22 (low gluten) were grown in rain-controlled conditions under two nitrogen levels, that is, N180 (N1) and N300 (N2). Drought priming was applied at the jointing stage and drought stress was applied 7 days after anthesis. Drought stress reduced starch content but enhanced protein content in grains. N2 and primed plants kept higher contents of nonstructural carbohydrates, fructans, and sucrose; with higher activity of sucrose-phosphate synthase in flag leaves. Furthermore, N2 and priming treatments showed higher sink ability to develop grains by showing higher sucrose-to-starch conversion activities of adenosine diphosphate-glucose pyrophosphorylase, uridine diphosphate glucose pyrophosphorylase, sucrose-synthase, soluble-starch synthase, starch branching enzyme, and granule-bound starch synthase as compared to N1 and non-primed treatments. The application of N2 and primed treatment showed a greater ability to maintain grain filling in both cultivars as compared to N1 and non-primed crops. Our study suggested that high nitrogen has the potential to enhance the effect of pre-drought priming to change source-sink relationships and grain yield of wheat under drought stress during the filling process.
Sujet(s)
Azote , Amidon , Triticum , Sécheresses , Grains comestibles/métabolisme , Glutens/métabolisme , Glutens/pharmacologie , Azote/métabolisme , Amidon/métabolisme , Saccharose/métabolisme , Triticum/physiologieRÉSUMÉ
The endogenous stimulating molecule melatonin (N-acetyl-5-methoxytryptamine, MT) has an important function in mitigating the impact of multiple abiotic stressors. However, the ameliorating effect of MT on chromium (Cr) stress and its mechanisms remains unclear. Therefore, the present study aimed to clarify the mitigating effect of exogenous MT (0 µM and 100 µM) on wheat seedlings under Cr (0 µM and 50 µM) stress stemming from the growth and physiological characteristics, phytochelatin (PC) biosynthesis, Cr subcellular distribution, and antioxidant system of the plants in these treatments. The results showed that endogenous MT application significantly promoted plant growth and improved root morphology of wheat seedlings under Cr stress due to decreased Cr and reactive oxygen species (ROS) accumulation in both roots and leaves. Accumulation and transport of Cr from roots to leaves were reduced by MT, because enhanced vacuolar sequestration via upregulated PC accumulation, took place, derived from the fact that MT upregulated the expression of key genes for PC synthesis (TaPCS and Taγ-ECS). Furthermore, MT pre-treatment alleviated Cr-induced oxidative damage by diminishing lipid peroxidation and cell apoptosis, profiting from the enhanced scavenging ability of ROS as a result of the MT-induced increase in the activities of superoxide dismutase, catalase, ascorbate peroxidase, and glutathione reductase, and the related encoding gene expression levels of TaSOD2, TaCAT, TaAPX, and TaGR. In conclusion, endogenous MT application improved the growth traits, antioxidant system, and decreased Cr accumulation especially at the leaf level in wheat seedlings under Cr stress mainly through enhancing antioxidant enzyme activities and altering Cr subcellular distribution via strengthening PC biosynthesis. The mechanisms of MT-induced plant tolerance to Cr stress could help develop new strategies for secure crop production in Cr-polluted soils.
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Antioxydants , Mélatonine , Antioxydants/métabolisme , Mélatonine/pharmacologie , Mélatonine/métabolisme , Plant , Triticum/métabolisme , Espèces réactives de l'oxygène/métabolisme , Chrome/toxicité , Chrome/métabolisme , Stress oxydatif , Peroxyde d'hydrogène/métabolismeRÉSUMÉ
Haze pollution has been a public health issue. The skin microbiota, as a component of the first line of defense, is disturbed by environmental pollutants, which may have an impact on human health. A total of 74 skin samples from healthy students were collected during haze and nonhaze days in spring and winter. Significant differences of skin fungal community composition between haze and nonhaze days were observed in female and male samples in spring and male samples in winter based on unweighted UniFrac distance analysis. Phylogenetic diversity whole-tree indices and observed features were significantly increased during haze days in male samples in winter compared to nonhaze days, but no significant difference was observed in other groups. Dothideomycetes, Capnodiales, Mycosphaerellaceae, etc. were significantly enriched during nonhaze days, whereas Trichocomaceae, Talaromyces, and Pezizaceae were significantly enriched during haze days. Thus, five Talaromyces strains were isolated, and an in vitro culture experiment revealed that the growth of representative Talaromyces strains was increased at high concentrations of particulate matter, confirming the sequencing results. Furthermore, during haze days, the fungal community assembly was better fitted to a niche-based assembly model than during nonhaze days. Talaromyces enriched during haze days deviated from the neutral assembly process. Our findings provided a comprehensive characterization of the skin fungal community during haze and nonhaze days and elucidated novel insights into how haze exposure influences the skin fungal community. IMPORTANCE Skin fungi play an important role in human health. Particulate matter (PM), the main haze pollutant, has been a public environmental threat. However, few studies have assessed the effects of air pollutants on skin fungi. Here, haze exposure influenced the diversity and composition of the skin fungal community. In an in vitro experiment, a high concentration of PM promoted the growth of Talaromyces strains. The fungal community assembly is better fitted to a niche-based assembly model during haze days. We anticipate that this study may provide new insights on the role of haze exposure disturbing the skin fungal community. It lays the groundwork for further clarifying the association between the changes of the skin fungal community and adverse health outcomes. Our study is the first to report the changes in the skin fungal community during haze and nonhaze days, which expands the understanding of the relationship between haze and skin fungi.
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Mycobiome , Talaromyces , Humains , Talaromyces/génétique , Taille de particule , Phylogenèse , Microbiologie de l'air , Surveillance de l'environnement , Matière particulaire/analyseRÉSUMÉ
The impact of ammonium (NH4+) stress on plant growth varies across species and cultivars, necessitating an in-depth exploration of the underlying response mechanisms. This study delves into elucidating the photosynthetic responses and differences in tolerance to NH4+ stress by investigating the effects on two wheat (Triticum aestivum L.) cultivars, Xumai25 (NH4+-less sensitive) and Yangmai20 (NH4+-sensitive). The cultivars were grown under hydroponic conditions with either sole ammonium nitrogen (NH4+, AN) or nitrate nitrogen (NO3-, NN) as the nitrogen source. NH4+ stress exerted a profound inhibitory effect on seedling growth and photosynthesis in wheat. However, these effects were less pronounced in Xumai25 than in Yangmai20. Dynamic photosynthetic analysis revealed that the suppression in photosynthesis was primarily attributed to stomatal limitation associated with a decrease in leaf water status and osmotic potential. Compared to Yangmai20, Xumai25 exhibited a significantly higher leaf K+ concentration and TaAKT1 upregulation, leading to a stronger stomatal opening and, consequently, a better photosynthetic performance under NH4+ stress. In conclusion, our study suggested stomatal limitation as the primary factor restricting photosynthesis under NH4+ stress. Furthermore, we demonstrated that improved regulation of osmotic substances contributed to higher stomatal conductance and enhanced photosynthetic performance in Xumai25.
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Shoot branching is inhibited by a low red/far-red ratio (R/FR). Prior studies have shown that the R/FR suppressed Arabidopsis thaliana branching by promotes bud abscisic acid (ABA) accumulation directly. Given that wheat tiller buds are wrapped in leaf sheaths and may not respond rapidly to a R/FR, systemic cytokinin (CTK) may be more critical. Here, systemic hormonal signals including indole-3-acetic acid (IAA), gibberellins (GA) and CTK and bud ABA signals in wheat were tested under a low R/FR. The results showed that a low R/FR reduced the percentage of tiller occurrence of tiller IV and the tiller number per plant. The low R/FR did not rapidly induced ABA accumulation in the tiller IV because of the protection of the leaf sheath and had little effect on IAA content and signaling in the tiller nodes. The significant change in the CTK levels was observed earlier than those of other hormone (ABA, IAA and GA) and exogenous cytokinin restored the CTK levels and tiller number per plant under low R/FR conditions. Further analysis revealed that the decrease in cytokinin levels was mainly associated with upregulation of cytokinin degradation genes (TaCKX5, TaCKX11) in tiller nodes. In addition, exposure to a decreased R/FR upregulated the expression of GA biosynthesis genes (TaGA20ox1, TaGA3ox2), resulting in elevated GA levels, which might further promote CTK degradation in tiller nodes and inhibit tillering. Therefore, our results provide evidence that the enhancement of cytokinin degradation is a novel mechanism underlying the wheat tillering response to a low R/FR.
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Background: Psoriasis is a chronic skin disease characterized by hyperproliferation of keratinocytes and increased inflammation. Previous studies have detected the levels of cytokines in the serum of patients with psoriasis, yet few multi-cytokine combination studies have been reported. Objective: The aim of the study was to compare the levels of cytokines in the serum between patients with psoriasis and healthy controls, elucidate which factors influence the psoriasis progression. Methods: A total of 39 psoriasis patients and 30 healthy volunteers were enrolled. The venous blood was collected and the levels of 13 inflammatory cytokines were measured by human inflammation panel 1 kit. The severity of the disease was determined according to the psoriasis area and severity index (PASI) score. Results: Compared with healthy controls, the levels of nine cytokines (IFN-γ, TNF-α, IL-1ß, IL-6, IL-10, IL-12P40, IL-18, IL-17A and IL-23) were significantly increased, while the level of MCP-1 decreased in psoriatic patients. In addition, except for MCP-1, IL-10 and IL-12P40, these cytokine levels were positively correlated with the PASI score. Furthermore, there were higher serum lever of IFN-γ, TNF-α, IL-1ß, IL-6, IL-17A, IL-18 and IL-23 in active psoriasis than healthy controls and retrograde psoriasis. Conclusions: Increased serum levels of IFN-γ, TNF-α, IL-1ß, IL-6, IL-17A, IL-18 and IL-23 in psoriatic patients were associated with PASI and the stage of disease, which suggested that these cytokines play an important role in the pathogenesis of psoriasis. The detection of these cytokines can better observe the disease activity of psoriasis and optimize the treatment strategy.
RÉSUMÉ
Hypertension is a major threat to human health. Eucommia ulmoides Oliv. (EU) is a small tree and EU extract is widely used to improve hypertension in East Asia. However, its major constituents have poor absorption and stay in the gut for a long time. The role of the gut microbiota in the anti-hypertensive effects of EU is unclear. Here, we examined the anti-hypertensive effects of EU in high-salt diet and N(omega)-nitro-L-arginine methyl ester (L-NAME) induced mice. After receiving EU for 6 weeks, the blood pressure was significantly reduced and the kidney injury was improved. Additionally, EU restored the levels of inflammatory cytokines, such as serum interleukin (IL)-6 and IL-17A, and renal IL-17A. The diversity and composition of the gut microbiota were influenced by administration of EU; 40 significantly upregulated and 107 significantly downregulated amplicon sequence variants (ASVs) were identified after administration of EU. ASV403 (Parabacteroides) was selected as a potential anti-hypertensive ASV. Its closest strain XGB65 was isolated. Furthermore, animal studies confirmed that Parabacteroides strain XGB65 exerted anti-hypertensive effects, possibly by reducing levels of inflammatory cytokines, such as renal IL-17A. Our study is the first to report that EU reduces blood pressure by regulating the gut microbiota, and it enriches the Parabacteroides strain, which exerts anti-hypertensive effects. These findings provide directions for developing novel anti-hypertensive treatments by combining probiotics and prebiotics.
RÉSUMÉ
Water and nitrogen (N) deficiencies are the major limitations to crop production, particularly when they occur simultaneously. By supporting metabolism, even when tissue water capacity is lower, nitrogen and priming may reduce drought pressure on plants. Therefore, the current study investigates the impact of nitrogen and priming on wheat to minimize post-anthesis drought stress. Plant morphology, physiology, and biochemical changes were observed before, during, and after stress at the post-anthesis stage. The plants were exposed to three water levels, i.e., well watering (WW), water deficit (WD), and priming at jointing and water deficit (PJWD) at the post-anthesis stage, and two different nitrogen levels, i.e., N180 (N1) and N300 (N2). Nitrogen was applied in three splits, namely, sowing, jointing, and booting stages. The results showed that the photosynthesis of plants with N1 was significantly reduced under drought stress. Moreover, drought stress affected chlorophyll (Chl) fluorescence and water-related parameters (osmotic potential, leaf water potential, and relative water content), grain filling duration (GFD), and grain yield. In contrast, PJWD couple with high nitrogen treatment (N300 kg ha-1) induced the antioxidant activity of peroxidase (37.5%), superoxide dismutase (29.64%), and catalase (65.66%) in flag leaves, whereas the levels of hydrogen peroxide (H2O2) and superoxide anion radical (O2 -) declined by 58.56 and 66.64%, respectively. However, during the drought period, the primed plants under high nitrogen treatment (N300 kg ha-1) maintained higher Chl content, leaf water potential, and lowered lipid peroxidation (61%) (related to higher activities of ascorbate peroxidase and superoxide dismutase). Plants under high nitrogen treatment (N300 kg ha-1) showed deferred senescence, improved GFD, and grain yield. Consequently, the research showed that high nitrogen dose (N300 kg ha-1) played a synergistic role in enhancing the drought tolerance effects of priming under post-anthesis drought stress in wheat.
RÉSUMÉ
BACKGROUND: Psoriasis vulgaris (PsV) is an immune-mediated skin disease of unknown mechanism. Interleukin 33 (IL-33) is a member of IL-1 cytokine family and suppression of tumorigenicity 2 (ST2) is the specific ligand of IL-33. It has been found that IL-33 and ST2 are increased in psoriatic lesions, but the expression levels in serum and their relationship to clinical features are still unclear. The aim of this study is to assess IL-33, ST2, IL-17 and IL-5 serum levels as well as serum concentration of blood glucose and blood lipids in PsV patients and their relationship with clinical characteristics. METHODS: Sixty-eight PsV samples and 60 healthy individuals were recruited. Serum levels of IL-33, ST2, IL-17 and IL-5 were measured by enzyme-linked immunosorbent assay and blood glucose and blood lipid were assayed by automatic biochemical analyzer. RESULTS: Serum levels of IL-33, ST2, IL-17 and IL-5 were increased significantly in PsV patients compared with controls (P<0.01). Cytokines were overexpressed in PsV patients during active stages compared with controls (P<0.05). Expression levels of IL-33, ST2 and IL-17 confirmed a significance in different severity groups of PsV patients (P<0.05). Serum concentration of triglyceride (TG) was also increased compared with controls (P=0.024). IL-33 levels were positively correlated with total cholesterol (TC) levels (r=0.319, P=0.008). CONCLUSION: IL-33/ST2 could generally reflect the activity and disease severity in PsV patients, which indicates that the IL-33/ST2 signaling pathway plays an important role in the pathogenesis of PsV.