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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.
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Plântula , Tetrazóis , Tiazóis , Triticum , Triticum/genética , Nitrogênio/metabolismo , Plantas/metabolismoRESUMO
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.
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Nitrogênio , Fotossíntese , Ribulose-Bifosfato Carboxilase , Triticum , Fotossíntese/fisiologia , Triticum/fisiologia , Triticum/genética , Triticum/metabolismo , Nitrogênio/metabolismo , Ribulose-Bifosfato Carboxilase/metabolismo , Estresse Fisiológico , Folhas de Planta/fisiologia , Folhas de Planta/metabolismo , Adaptação Fisiológica , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Clorofila/metabolismo , Complexo de Proteína do Fotossistema II/metabolismo , Glucosiltransferases/metabolismo , Glucosiltransferases/genéticaRESUMO
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.
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Ribulose-Bifosfato Carboxilase , Triticum , Triticum/genética , Fotossíntese , Metabolismo dos Carboidratos , SacaroseRESUMO
Stabilization of a G-quadruplex (G4) in the promotor of the c-MYC proto-oncogene leads to inhibition of gene expression, and it thus represents a potentially attractive new strategy for cancer treatment. However, most G4 stabilizers show little selectivity among the many G4s present in the cellular complement of DNA and RNA. Intriguingly, a crescent-shaped cell-penetrating thiazole peptide, TH3, preferentially stabilizes the c-MYC G4 over other promotor G4s, but the mechanisms leading to this selective binding remain obscure. To investigate these mechanisms at the atomic level, we performed an in silico comparative investigation of the binding of TH3 and its analogue TH1 to the G4s from the promotors of c-MYC, c-KIT1, c-KIT2, and BCL2. Molecular docking and molecular dynamics simulations, combined with in-depth analyses of non-covalent interactions and bulk and per-nucleotide binding free energies, revealed that both TH3 and TH1 can induce the formation of a sandwich-like framework through stacking with both the top and bottom G-tetrads of the c-MYC G4 and the adjacent terminal capping nucleotides. This framework produces enhanced binding affinities for c-MYC G4 relative to other promotor G4s, with TH3 exhibiting an outstanding binding priority. Van der Waals interactions were identified to be the key factor in complex formation in all cases. Collectively, our findings fully agree with available experimental data. Therefore, the identified mechanisms leading to specific binding of TH3 towards c-MYC G4 provide valuable information to guide the development of new selective G4 stabilizers.
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Genes myc , Simulação de Acoplamento Molecular , Peptídeos/farmacologia , Tiazóis/farmacologiaRESUMO
BACKGROUND: Cerebral infarction is a local or extensive necrosis of brain tissue. Subsequently, the corresponding neurological deficits appear. The incidence of cerebrovascular diseases in China is increasing gradually. After the onset of cerebrovascular disease, the most common sequelae include movement disorders, language disorders, and cognitive dysfunction. AIM: To investigate the effect of early refined nursing program on the prognosis of middle-aged and elderly patients with cerebral infarction combined with cognitive dysfunction. METHODS: A retrospective study was conducted to divide 60 patients with cerebral infarction and cognitive impairment into an experimental group (n = 32) and a control group (n = 28). The experimental group received early intensive care every day, and the control group received daily routine care. The scores of the Mini-Mental State Examination (MMSE) and the Trail Making Test (TMT), as well as the latency and amplitude of the event-related potential P300, were used as main indicators to evaluate changes in cognitive function, and changes in BDNF, TGF-ß, and GDNF expression were used as secondary indicators. RESULTS: Both groups experienced notable enhancements in MMSE scores, with the experimental group demonstrating higher scores than the control group (experimental: 28.75 ± 2.31; control: 25.84 ± 2.87). Moreover, reductions in TMT-A and TMT-B scores were observed in both groups (experimental: TMT-A 52.36 ± 6.18, TMT-B 98.47 ± 10.23; control: TMT-A 61.48 ± 7.92, TMT-B 112.63 ± 12.55), with the experimental group displaying lower scores. P300 Latency decreased (experimental: 270.63 ms ± 14.28 ms; control: 285.72 ms ± 16.45 ms), while amplitude increased (experimental: 7.82 µV ± 1.05 µV; control: 6.35 µV ± 0.98 µV) significantly in both groups, with superior outcomes in the experimental cohort. Additionally, the levels of the growth factors BDNF, TGF-ß1, and GDNF surged (experimental: BDNF 48.37 ng/mL ± 5.62 ng/mL, TGF-ß1 52.14 pg/mL ± 4.28 pg/mL, GDNF 34.76 ng/mL ± 3.89 ng/mL; control: BDNF 42.58 ng/mL ± 4.73 ng/mL, TGF-ß1 46.23 pg/mL ± 3.94 pg/mL, GDNF 30.25 ng/mL ± 2.98 ng/mL) in both groups, with higher levels in the experimental group. CONCLUSION: For middle-aged and elderly patients with cerebral infarction and cognitive dysfunction, early refined nursing can significantly improve their cognitive function and prognosis.
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Parkinson's disease (PD), the second most common neurodegenerative disorder, is linked to α-synuclein (α-Syn) aggregation. Despite no specific drug being available for its treatment, curcumin, from the spice turmeric, shows promise. However, its application in PD is limited by a lack of understanding of its anti-amyloidogenic mechanisms. In this study, we first reconstructed the liquid-liquid phase separation (LLPS) of α-Syn in vitro under different conditions, which may be an initial step in entraining the pathogenic aggregation. Subsequently, we evaluated the effects of curcumin on the formation of droplets, oligomers, and aggregated fibers during the LLPS of α-synuclein, as well as its impact on the toxicity of aggregated α-synuclein to cultured cells. Importantly, we found that curcumin can inhibit amyloid formation by inhibiting the occurrence of LLPS and the subsequent formation of oligomers of α-Syn in the early stages of aggregation. Finally, the molecular dynamic simulations of interactions between α-Syn decamer fibrils and curcumin showed that van der Waal's interactions make the largest contribution to the anti-aggregation effect of curcumin. These results may help to clarify the mechanism by which curcumin inhibits the formation of α-Syn aggregates during the development of PD.
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OBJECTIVE: To explore the effects of a 12-week aerobic exercise program with different frequencies on executive functions (EFs) in preschool children. METHOD: Four kindergartens, comprising 126 preschool children in Shanghai, were enrolled in this 12-week cluster randomized controlled trial with a 12-week follow-up period. Kindergartens were allocated to high-frequency (three times a week) or low-frequency (once a week) exercise groups using stratified block randomization. Three core sub-EFs, including inhibition, working memory, and cognitive flexibility, were assessed at baseline, post-intervention, and the 12-week follow-up. RESULTS: Compared to baseline, both groups showed significant improvements in inhibition and working memory after the intervention and at the 12-week follow-up. However, only the high-frequency exercise group demonstrated a significant improvement in cognitive flexibility after the follow-up period. Nonetheless, there were no significant differences in the core sub-functions of EFs between the two groups at the end of the intervention or the follow-up periods. CONCLUSION: A 12-week aerobic exercise of three times a week was insufficient to significantly improve EFs in preschool children compared to once a week. Future studies are needed to examine the dose-response relationship of aerobic exercise on EFs and to verify the effects of different exercise modalities on EFs in preschool children.
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The hard-healing chronic wounds of diabetics are still one of the most intractable problems in clinical skin injury repair. Wound microenvironments directly affect wound healing speed, but conventional dressings exhibit limited efficacy in regulating the wound microenvironment and facilitating healing. To address this serious issue, we designed a thermo-sensitive drug-controlled hydrogel with wound self-adjusting effects, consisting of a sodium alginate (SA), Antheraeapernyi silk gland protein (ASGP) and poly(N-isopropylacrylamide) (PNIPAM) for a self-adjusting microenvironment, resulting in an intelligent releasing drug which promotes skin regeneration. PNIPAM has a benign temperature-sensitive effect. The contraction, drugs and water molecules expulsion of hydrogel were generated upon surpassing lower critical solution temperatures, which made the hydrogel system have smart drug release properties. The addition of ASGP further improves the biocompatibility and endows the thermo-sensitive drug-controlled hydrogel with adhesion. Additionally, in vitro assays demonstrate that the thermo-sensitive drug-controlled hydrogels have good biocompatibility, including the ability to promote the adhesion and proliferation of human skin fibroblast cells. This work proposes an approach for smart drug-controlled hydrogels with a thermo response to promote wound healing by self-adjusting the wound microenvironment.
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Background: Plant cell suspension culture of Vitis vinifera is a promising technology for investigating different factors that are able to induce and/or modify stilbenes biosynthesis. Jasmonates have been reported to play an important role in a signal transduction pathway that regulates defence responses as well as the production of secondary metabolites. In this study, 2, 3-dihydroxypropyl jasmonate (DHPJA) was used to investigate its effect on stimulating trans-resveratrol (t-R) accumulation and the plant defence responses in Vitis vinifera cv. Kyoho cell suspension cultures for the first time. Results: It demonstrated that DHPJA had superior effects on stilbenoids accumulation over methyl jasmonate (MeJA). The optimal condition was 150 uM DHPJA added on day 15 of cultivation period, with the highest level of t-R accumulation which was increased 1.8-fold and 1.3-fold compared with the control and 150 uM MeJA respectively. DHPJA induced stronger plant defence responses, including oxidative burst and activation of L-phenylalanine ammonia lyase (PAL) than MeJA. H2O2 generation induced by DHPJA played a significant role in enhancing t-R accumulation. Adding a specific inhibitor of H2O2 signalling pathway inhibited DHPJA-induced t-R accumulation, but had no effects on DHPJA-induced other metabolites accumulation, which resulted in regulations of product diversity. Conclusions: This study demonstrated that DHPJA was an efficient elicitor to enhance t-R accumulation by activating stronger oxidative burst, and H2O2 signalling pathway could regulate product diversity in DHPJA-induced V. vinifera cv. Kyoho cell suspension cultures.