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1.
Sci Rep ; 11(1): 19689, 2021 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-34608242

RESUMO

Subclinical hypothyroidism (SCH) has become a prevalent complication in pregnancy. Recent research links SCH to disturbed thyroid lipid profile; however, it is unclear how lipid metabolism disorders contribute to the pathogenesis of SCH during pregnancy. Thus, we used nontargeted lipidomics to identify and compare the lipids and metabolites expressed by pregnant women with SCH and healthy pregnant women. Multivariate analysis revealed 143 lipid molecules differentially expressed between the SCH group and the control group. Based on fold change, 30 differentially expressed lipid metabolites are potential biomarkers. KEGG pathway enrichment analysis showed that the differentially expressed metabolites participate in several pathways, including response to pathogenic Escherichia coli infection, regulation of lipolysis in adipocytes, metabolic pathways, glycerophospholipid metabolism, and fat digestion and absorption pathways. Correlation analyses revealed sphingomyelin (SM) and phosphatidylcholine (PC) positively correlate to tumor necrosis factor-α (TNF-α), C-reactive protein (CRP), and interleukin-6 (IL-6), while phosphatidylglycerol (PG), and phosphatidylinositol (PI) negatively correlate with them. In addition, PG positively correlates to birth weight. Thus, the lipid profile of pregnant women with SCH is significantly different from that of healthy pregnant women. Lipid molecules associated with the differential lipid metabolism, such as SM, phosphatidylethanolamine (PE), and PI, should be further investigated for their roles in the pathogenesis of SCH in pregnancy, as they might be targets for reducing the incidence of adverse pregnancy outcomes.

2.
Blood Adv ; 5(18): 3656-3667, 2021 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-34470047

RESUMO

Proteasome inhibitors, such as bortezomib (BTZ), represent the key elements in chemotherapy regimens for multiple myeloma (MM), whereas acquired chemoresistance and ultimately relapse remain a major obstacle. In the current study, we screened differently expressed cytokines in bortezomib-resistant MM cells and found that Dickkopf-1 (DKK1) level was remarkably augmented, whereas CD138 level was significantly suppressed. DKK1 in vitro specifically enhanced the resistance of myeloma cells to bortezomib treatment, and excessive DKK1 drove CD138 downregulation via inhibition of canonical Wnt signaling. Notably, DKK1 mainly induced drug resistance in MM cells via the receptor of CKAP4. Mechanistically, CKAP4 transduced DKK1 signal and evoked NF-κB pathway through recruiting and preventing cullin associated and neddylation dissociated 1 from hampering the assembly of E3 ligase-mediated ubiquitination of IκBα. In addition, we found that interleukin-6 (IL-6) stimulated CKAP4 expression to generate drug resistance, and disturbance of DKK1-CKAP4 axis improved sensitivity to BTZ treatment of MM and attenuated bone destruction in a mouse model. Collectively, our study revealed the previously unidentified role of DKK1 in myeloma drug resistance via Wnt signaling dependent and independent manners, and clarified the importance of antagonism of DKK1-IL-6 loop in bone marrow microenvironment.

3.
Colloids Surf B Biointerfaces ; 207: 112039, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34416444

RESUMO

In this present work, we have successfully designed and investigated three flavonoid sunscreen compounds. Based on steady-state spectroscopy and time-dependent density functional theory (TDDFT), the mechanism of excited state intramolecular proton transfer (ESIPT) of sunscreen compounds was studied. The calculated UV-vis absorption spectra and fluorescence emission spectra are in good agreement with the experimental results in methanol solution. The potential energy curve demonstrates that the ESIPT process can easily occur in the three sunscreen compounds without energy barrier. Therefore, the absorbed excitation energy can get back to the ground state through a non-radiative relaxation process. Light stability tests ensure that the three flavonoids have the potential as sunscreens. This work provides not only an application of the ESIPT process in sunscreen mechanisms, but also a theory basis for the development of novel sunscreen molecules.


Assuntos
Prótons , Protetores Solares , Modelos Moleculares , Teoria Quântica , Espectrometria de Fluorescência
4.
Front Public Health ; 9: 615152, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34336751

RESUMO

Human death and life span are closely related to the geographical environment and regional lifestyle. These factors considerably vary among counties and regions, leading to the geographical disparity of disease. Quantitative studies on this phenomenon are insufficient. Cerebrovascular and heart diseases are the leading causes of death. The mortality rate of cerebrovascular and heart diseases is statistically higher in northern China than in southern China; the p-value of t-test for cerebrovascular and heart diseases was 0.047 and 0.000, respectively. The population attribution fraction of 12 major risk factors for cardiovascular disease (CVD) in each province was calculated based on their exposure and relative risk. The results found that residents in northern China consume high sodium-containing food, fewer vegetables, and less sea food products, and tend to be overweight. Fine particulate matter is higher in northern China than in southern China. Cold temperatures also cause a greater number of deaths than hot temperatures. All these factors have resulted in a higher CVD mortality rate in northern China. The attributive differential for sodium, vegetable, fruit, smoking, PM2.5, omega-3, obesity, low temperature, and high temperature of heart disease between the two parts of China is 9.1, 0.7, -2.5, 0.1, 1.4, 1.3, 2.0, 4.7, and -2.1%, respectively. Furthermore, the attributive differential for the above factors of cerebrovascular disease between the two parts of China is 8.7, 0.0, -5.2, 0.1, 1.0, 0.0, 2.4, 4.7, and -2.1%. Diet high in sodium is the leading cause of the north-south differential in CVD, resulting in 0.71 less years of life expectancy in northern compared with that in southern China.


Assuntos
Doenças Cardiovasculares , Doenças Cardiovasculares/epidemiologia , China/epidemiologia , Humanos , Estilo de Vida , Material Particulado/toxicidade , Fatores de Risco
5.
Sci Adv ; 7(32)2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34362736

RESUMO

The use of entangled sensors improves the precision limit from the standard quantum limit (SQL) to the Heisenberg limit. Most previous experiments beating the SQL are performed on the sensors that are well isolated under extreme conditions. Here, we demonstrate a sub-SQL interferometer at ambient conditions by using a multispin system, namely, the nitrogen-vacancy (NV) defect in diamond. We achieve two-spin interference with a phase sensitivity of 1.79 ± 0.06 dB beyond the SQL and three-spin interference with a phase sensitivity of 2.77 ± 0.10 dB. Besides, a magnetic sensitivity of 0.87 ± 0.09 dB beyond the SQL is achieved by two-spin interference for detecting a real magnetic field. Particularly, the deterministic and joint initialization of NV negative state, NV electron spin, and two nuclear spins is realized at room temperature. The techniques used here are of fundamental importance for quantum sensing and computing, and naturally applicable to other solid-state spin systems.

6.
J Phys Chem B ; 125(33): 9572-9578, 2021 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-34433282

RESUMO

Nowadays, traditional sunscreen molecules face many adverse problems: single energy relaxation pathway, lack of adequate UVA light protection, and therefore no longer meeting the growing demand for UVA protection. In this work, we reported a novel sunscreen molecule (E)-3-(5-bromofuran-2-yl)-1-(2-hydroxyphenyl)prop-2-en-1-one (hereinafter referred to as FPPO-HBr) which tackled adverse problems of traditional sunscreen molecules as single energy relaxation pathway, lacking effective UVA light protection. Various nonradiative pathways were proposed and verified by combining the steady-state and femtosecond transient absorption (FTA) spectroscopy and theoretical calculation. Upon UV excitation, the FPPO-HBr mainly decays via excited-state intramolecular proton transfer (ESIPT) followed by conformation twist in ultrafast manner. Importantly, 1H NMR spectra proved that the FPPO-HBr could not undergo trans-cis photoisomerization. Additionally, excellent photostability was also observed for newly synthesized FPPO-HBr. The current work could provide new perspectives for sunscreen molecules synthesis and mechanism.

7.
J Agric Food Chem ; 69(33): 9557-9570, 2021 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-34382800

RESUMO

Succinate dehydrogenase inhibitors (SDHIs) have emerged in fungicide markets as one of the fastest-growing categories that are widely applied in agricultural production for crop protection. Currently, the structural modification focusing on the flexible amide link of SDHI molecules is being gradually identified as one of the innovative strategies for developing novel highly efficient and broad-spectrum fungicides. Based on the above structural features, a series of pyrazole-4-acetohydrazide derivatives potentially targeting fungal SDH were constructed and evaluated for their antifungal effects against Rhizoctonia solani, Fusarium graminearum, and Botrytis cinerea. Strikingly, the in vitro EC50 values of constructed pyrazole-4-acetohydrazides 6w against R. solani, 6c against F. graminearum, and 6f against B. cinerea were, respectively, determined as 0.27, 1.94, and 1.93 µg/mL, which were obviously superior to that of boscalid against R. solani (0.94 µg/mL), fluopyram against F. graminearum (9.37 µg/mL), and B. cinerea (1.94 µg/mL). Concurrently, the effects of the substituent steric, electrostatic, hydrophobic, and hydrogen-bond fields on structure-activity relationships were elaborated by the reliable comparative molecular field analysis and comparative molecular similarity index analysis models. Subsequently, the practical value of pyrazole-4-acetohydrazide derivative 6w as a potential SDHI was ascertained by the relative surveys on the in vivo anti-R. solani preventative efficacy, inhibitory effects against fungal SDH, and molecular docking studies. The present results provide an indispensable complement for the structural optimization of antifungal leads potentially targeting SDH.


Assuntos
Fungicidas Industriais , Succinato Desidrogenase , Botrytis , Fungicidas Industriais/farmacologia , Fusarium , Hidrazinas , Simulação de Acoplamento Molecular , Doenças das Plantas , Pirazóis/farmacologia , Relação Quantitativa Estrutura-Atividade , Rhizoctonia , Relação Estrutura-Atividade , Succinato Desidrogenase/metabolismo
8.
Phys Rev Lett ; 127(5): 053601, 2021 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-34397227

RESUMO

Atomiclike defects in solids are not considered to be identical owing to the imperfections of host lattice. Here, we found that even under ambient conditions, negatively charged nitrogen-vacancy (NV^{-}) centers in diamond could still manifest identical at Hz-precision level, corresponding to a 10^{-7}-level relative precision, while the lattice strain can destroy the identity by tens of Hz. All parameters involved in the NV^{-}-^{14}N Hamiltonian are determined by formulating six nuclear frequencies at 10-mHz-level precision and measuring them at Hz-level precision. The most precisely measured parameter, the ^{14}N quadrupole coupling P, is given by -494 575 4.9(8) Hz, whose precision is improved by nearly 4 orders of magnitude compared with previous measurements. We offer an approach for performing precision measurements in solids and deepening our understandings of NV centers as well as other solid-state defects. Besides, these high-precision results imply a potential application of a robust and integrated atomiclike clock based on ensemble NV centers.

9.
Food Chem ; 365: 130615, 2021 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-34329877

RESUMO

Chiral volatile compounds are known to be distributed in teas at various enantiomeric ratios. However, the performance of each enantiomer, including aroma characteristics, aroma intensities, and contribution to the overall flavor of tea, is still unclear. In this study, aroma characteristics and intensities of 38 volatile enantiomers in standards and baked green teas with chestnut-like aroma and clean aroma were evaluated by an efficient sequential headspace-stir bar sorptive extraction (seq-HS-SBSE) approach combined with the enantioselective gas chromatography-olfactometry/mass spectrometry (Es-GC-O/MS) technique. Moreover, aroma recombination results for the two types of baked green teas using 14 chiral odorants and four achiral odorants indicated that the combinations of the detected odorants mainly contributed to the "floral", "sweet", and "chestnut-like" aromas. R-Linalool simultaneously enhanced the "floral", "sweet", and "chestnut-like" aromas; R-limonene mainly contributed to the "sweet" and "clean" aromas; and S-α-terpineol promoted the "sweet" and "floral" aromas of baked green tea.


Assuntos
Odorantes , Compostos Orgânicos Voláteis , Aromatizantes , Cromatografia Gasosa-Espectrometria de Massas , Odorantes/análise , Olfatometria , Chá , Compostos Orgânicos Voláteis/análise
10.
Hum Cell ; 34(6): 1617-1628, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34324139

RESUMO

Emergent studies reveal the roles of inflammatory cells and cytokines in the development of diabetic retinopathy (DR), which is gradually portrayed as a chronic inflammatory disease accompanied by metabolic disorder. Through the pathogenesis of DR, macrophages or microglia play a critical role in the inflammation, neovascularization, and neurodegeneration of the retina. Conventionally, macrophages are generally divided into M1 and M2 phenotypes which mainly rely on glycolysis and oxidative phosphorylation, respectively. Recently, studies have found that nutrients (including glucose and lipids) and metabolites (such as lactate), can not only provide energy for cells, but also act as signaling molecules to regulate the function and fate of cells. In this review, we discussed the intrinsic correlations among the metabolic status, polarization, and function of macrophage/microglia in DR. Hyperglycemia and hyperlipidemia could induce M1-like and M2-like macrophages polarization in different phases of DR. Targeting the regulation of microglial metabolic profile might be a promising therapeutic strategy to modulate the polarization and function of macrophages/microglia, thus attenuating the progression of DR.

11.
Rev Sci Instrum ; 92(5): 055001, 2021 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-34243241

RESUMO

The key component of the scanning magnetometry based on nitrogen-vacancy centers is the diamond probe. Here, we designed and fabricated a new type of probe with an array of pillars on a (100 µm)2 × 50 µm diamond chip. The probe features high yield, convertibility to be a single pillar, and expedient reusability. Our fabrication is dramatically simplified by using ultraviolet laser cutting to shape the chip from a diamond substrate instead of additional lithography and time-consuming reactive ion etching. As an example, we demonstrate the imaging of a single magnetic skyrmion with nanoscale resolution. In the future, this flexible probe will be particularly well-suited for commercial applications.

12.
Rev Sci Instrum ; 92(4): 045107, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-34243467

RESUMO

We develop a parallel optically detected magnetic resonance (PODMR) spectrometer to address, manipulate, and read out an array of single nitrogen-vacancy (NV) centers in diamond in parallel. In this spectrometer, we use an array of micro-lenses to generate a 20 × 20 laser-spot lattice (LSL) on the objective focal plane and then align the LSL with an array of single NV centers. The quantum states of NV centers are manipulated by a uniform microwave field from a Ω-shape coplanar coil. As an experimental demonstration, we observe 80 NV centers in the field of view. Among them, magnetic resonance (MR) spectra and Rabi oscillations of 18 NV centers along the external magnetic field are measured in parallel. These results can be directly used to realize parallel quantum sensing and multiple times speedup compared with the confocal technique. Regarding the nanoscale MR technique, PODMR will be crucial for a high throughput single molecular MR spectrum and imaging.

13.
Nanotechnology ; 2021 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-34237710

RESUMO

Polymer-based dielectric capacitors play a notable part in the practical application of energy storage devices. Graphene oxide (GO) nanosheets can improve the dielectric properties of polymer-based composites. However, the breakdown strength will greatly reduce with the increase of GO content. Hence, the construction of sandwich structure can enhance the breakdown strength without reducing the dielectric constant. Herein, single-layered and sandwich-structured poly(vinylidene fluoride-co-chlorotrifluoroethylene) (P(VDF-CTFE)) nanocomposites with low content of GO nanosheets (<1.0 wt.%) are prepared via employing a straightforward casting method. Compared with the single-layered composites and pure P(VDF-CTFE), the sandwich-structured composites exhibit comprehensively better performance compared. The sandwich-structured composite with 0.4 wt.% GO nanosheets show an excellent dielectric constant of 13.6 (at 1 kHz) and an outstanding discharged energy density of 8.25 J/cm3 at 3400 kV/cm. These results demonstrate that the growth of the dielectric properties is owing to 2D GO nanosheets and the enhancement of breakdown strength due to the sandwich structure. The results from finite element simulation provide theoretical support for the design of high energy density composites.

14.
West J Nurs Res ; : 1939459211028666, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-34196233

RESUMO

This study aimed to evaluate the association between night-time sleep duration and hand grip strength (HGS) among patients with chronic obstructive pulmonary disease (COPD). Participants aged ≥45 years were included in a nationally representative investigation clinical study in 2015. HGS was measured using dynamometers. The data on night-time sleep duration, sociodemographic information, and health-related variables were systematically collected. For analysis, sleep duration was categorized as <5 h, 5-7 h, 7 h, 7-9 h, and >9 h. Multivariable linear regression models were used to determine the possible association between the night-time sleep duration and HGS. Our results indicated that the shortest (<5 h) or the longest sleep duration (>9 h) was relevant to high risk of weaker HGS in females. In males, the shortest (<5 h) sleep duration was correlated to lower HGS. Thus, our findings clearly suggest that health care providers should focus on the potential influence of sleep duration on HGS among COPD patients.

15.
Mol Plant ; 14(10): 1640-1651, 2021 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-34171482

RESUMO

Apoplastic iron (Fe) in roots represents an essential Fe storage pool. Reallocation of apoplastic Fe is of great importance to plants experiencing Fe deprivation, but how this reallocation process is regulated remains elusive, likely because of the highly complex cell wall structure and the limited knowledge about cell wall biosynthesis and modulation. Here, we present genetic and biochemical evidence to demonstrate that the Cdi-mediated galactosylation of rhamnogalacturonan-II (RG-II) is required for apoplastic Fe reallocation. Cdi is expressed in roots and up-regulated in response to Fe deficiency. It encodes a putative glycosyltransferase localized to the Golgi apparatus. Biochemical and mass spectrometry assays showed that Cdi catalyzes the transfer of GDP-L-galactose to the terminus of side chain A on RG-II. Disruption of Cdi essentially decreased RG-II dimerization and hence disrupted cell wall formation, as well as the reallocation of apoplastic Fe from roots to shoots. Further transcriptomic, Fourier transform infrared spectroscopy, and Fe desorption kinetic analyses coincidently suggested that Cdi mediates apoplastic Fe reallocation through extensive modulation of cell wall components and consequently the Fe adsorption capacity of the cell wall. Our study provides direct evidence demonstrating a link between cell wall biosynthesis and apoplastic Fe reallocation, thus indicating that the structure of the cell wall is important for efficient usage of the cell wall Fe pool.

16.
Ecotoxicol Environ Saf ; 220: 112386, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34090108

RESUMO

Atrazine (ATR) is a herbicide used widely worldwide. Because of its prolonged persistence in the environment and accumulation in the body, ATR exposure is a potential threat to human health. Our previous study showed that subacute exposure to ATR suppresses cellular immune function in mice. In this study, the effects of long-term exposure to ATR on rat immunological system function were measured. Four-week-old female Sprague-Dawley (SD) rats were treated with 0.4 µmol/L, 2 µmol/L and 10 µmol/L ATR for 24 weeks. The results showed that the spleen index increased, white blood cells decreased, and monocytes and eosinophils increased. No obvious changes were detected in the numbers of neutrophils and lymphocytes. Th1, Th2, and Th17 cells decreased significantly, while Treg cells increased after long-term ATR exposure. Moreover, serum levels of cytokines, including TNF-α, INF-γ, IL-6, and IL-12, decreased, while IL-1, IL-4, and IL-5 increased. Degenerative changes and cell apoptosis were found in the spleen; Caspase-3 and Caspase-9 were upregulated, and Bcl-2 was downregulated. These results suggested that long-term ATR exposure may inhibit immune system function.


Assuntos
Apoptose/efeitos dos fármacos , Atrazina/toxicidade , Herbicidas/toxicidade , Baço/efeitos dos fármacos , Animais , Citocinas/genética , Citocinas/metabolismo , Feminino , Regulação da Expressão Gênica/efeitos dos fármacos , Camundongos , Ratos , Ratos Sprague-Dawley , Transdução de Sinais/efeitos dos fármacos , Baço/citologia , Linfócitos T Auxiliares-Indutores
17.
Neurosurg Rev ; 2021 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-34185189

RESUMO

This study evaluated the long-term efficacy of globus pallidus internus (GPi) deep brain stimulation (DBS) in the treatment of craniofacial dystonia (Meige syndrome) and investigated the correlation between the volume of tissue activated (VTA) in the GPi and each subregion and movement score improvement. We retrospectively analyzed the clinical data of 13 patients with drug-refractory Meige syndrome who were treated with GPi DBS. The pre- and postoperative Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) scores were compared. The relationships between the preoperative baseline variables and improvement in the BFMDRS-Movement (BFMDRS-M) score were analyzed. LEAD-DBS software was used for the three-dimensional reconstruction of the GPi and implanted electrodes. The correlations between the GPi-VTA and score improvement were analyzed. The average follow-up period was 36.6 ± 11.0 months (18-55 months). At 3 months after the stimulation and the final follow-up visit, the improvements in the BFMDRS-M score were 58.2 and 54.6%, and the improvements in the BFMDRS-Disability (BFMDRS-D) score were 53.6 and 51.7%, respectively. At the final follow-up visit, the improvements in the BFMDRS-M scores of the eye, mouth, and speech/swallowing were significant (P < 0.001). Age was an independent predictor of improvement in the BFMDRS-M score after DBS (P = 0.005). A decrease in the BFMDRS-M score was significantly positively correlated with the GPi-VTA (r = 0.757, P = 0.003). GPi DBS is an effective method for treating drug-refractory Meige syndrome. LEAD-DBS software can be used as an effective aid for visualization programming after DBS.

18.
Diabetes Res Clin Pract ; 176: 108818, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33932493

RESUMO

OBJECTIVE: Gestational diabetes mellitus (GDM) is a common complication of pregnancy. The purpose of this study was to compare the incidence of small intestinal bacterial overgrowth (SIBO) in patients with GDM and the control group by methane and hydrogen lactulose breath test (LBT), and to explore its relationship with inflammation, vitamins, and the outcomes of maternal and child. METHODS: LBT was detected in 220 GDM patients, 160 pregnancy control patients and 160 pre-pregnancy control patients. The fasting blood glucose, white blood cells, vitamin A, D, E, neonatal weight, neonatal blood glucose and so on were compared and analyzed. RESULTS: There was no statistical significance in the general data of the three groups. The proportion of abdominal distension in the GDM group was higher than that in the other two groups (P < 0.001). The positive rates of SIBO + in GDM group, gestational control group and pre-pregnancy control group were 54.55%, 27.50% and 14.38%, respectively. The average abundance of hydrogen and methane in GDM group was significantly higher than that in control group at each time point. In the GDM group, SIBO + subjects had higher levels of fasting blood glucose, glycoglycated hemoglobin, C-reactive protein, neonatal weight, and lower levels of vitamin D and neonatal blood glucose (P < 0.001). CONCLUSION: Patients with GDM have a high incidence of SIBO, and SIBO may further increase their blood glucose by affecting inflammatory response and vitamin level, and even affect the outcome of mother and child.


Assuntos
Diabetes Gestacional/diagnóstico , Disbiose/diagnóstico , Microbioma Gastrointestinal/fisiologia , Hidrogênio/análise , Metano/análise , Adulto , Glicemia/análise , Glicemia/metabolismo , Testes Respiratórios/métodos , Estudos de Casos e Controles , Diabetes Gestacional/metabolismo , Diabetes Gestacional/microbiologia , Disbiose/complicações , Disbiose/metabolismo , Feminino , Humanos , Hidrogênio/metabolismo , Recém-Nascido , Intestino Delgado/metabolismo , Intestino Delgado/microbiologia , Lactulose/análise , Lactulose/metabolismo , Metano/metabolismo , Gravidez , Complicações na Gravidez/diagnóstico , Complicações na Gravidez/metabolismo , Complicações na Gravidez/microbiologia , Respiração
19.
Spectrochim Acta A Mol Biomol Spectrosc ; 260: 119949, 2021 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-34023551

RESUMO

In this work, the nonadiabatic energy relaxation mechanism of hemicyanines for UV photoprotection were investigated by using the density functional theory (DFT) and time-dependent density functional theory (TDDFT) method for the first time. The absorption spectra and potential energy surfaces (PESs) of four hemicyanines with different positions of substituents were presented. The maximum absorption peaks of the four hemicyanines are located in the UVA region. In addition, all these hemicyanine molecules also have light absorption in both the UVB and UVC regions. At the same time, we found that the trans-cis photoisomerization PESs of all these hemicyanines have a significant conical intersection (CI) point between the first excited state and the ground state. Herein, it was first demonstrated that the UV energy absorbed by the hemicyanines could be dissipated nonadiabatically through the CI point by using the trans-cis photoisomerization dynamics mechanism. This work proves that hemicyanines have the possibility to be applied for UV photoabsorbers, and provides important basis for designing new type of hemicyanines for UV photoprotection.

20.
Antioxidants (Basel) ; 10(4)2021 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-33805859

RESUMO

Brassinosteroids (BRs) play a critical role in plant responses to stress. However, the interplay of BRs and reactive oxygen species signaling in cold stress responses remains unclear. Here, we demonstrate that a partial loss of function in the BR biosynthesis gene DWARF resulted in lower whilst overexpression of DWARF led to increased levels of C-REPEAT BINDING FACTOR (CBF) transcripts. Exposure to cold stress increased BR synthesis and led to an accumulation of brassinazole-resistant 1 (BZR1), a central component of BR signaling. Mutation of BZR1 compromised the cold- and BR-dependent increases in CBFs and RESPIRATORY BURST OXIDASE HOMOLOG 1(RBOH1) transcripts, as well as preventing hydrogen peroxide (H2O2) accumulation in the apoplast. Cold- and BR-induced BZR1 bound to the promoters of CBF1, CBF3 and RBOH1 and promoted their expression. Significantly, suppression of RBOH1 expression compromised cold- and BR-induced accumulation of BZR1 and related increases in CBF transcripts. Moreover, RBOH1-dependent H2O2 production regulated BZR1 accumulation and the levels of CBF transcripts by influencing glutathione homeostasis. Taken together, these results demonstrate that crosstalk between BZR1 and reactive oxygen species mediates cold- and BR-activated CBF expression, leading to cold tolerance in tomato (Solanum lycopersicum).

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