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1.
J Plant Physiol ; 260: 153388, 2021 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-33706055

RESUMO

In angiosperms, mature pollen is wrapped by a pollen wall, which is important for maintaining pollen structure and function. Pollen walls provide protection from various environmental stresses and preserve pollen germination and pollen tube growth. The pollen wall structure has been described since pollen ultrastructure investigations began in the 1960s. Pollen walls, which are the most intricate cell walls in plants, are composed of two layers: the exine layer and intine layer. Pollen wall formation is a complex process that occurs via a series of biological events that involve a large number of genes. In recent years, many reports have described the molecular mechanisms of pollen exine development. The formation process includes the development of the callose wall, the wavy morphology of primexine, the biosynthesis and transport of sporopollenin in the tapetum, and the deposition of the pollen coat. The formation mechanism of the intine layer is different from that of the exine layer. However, few studies have focused on the regulatory mechanisms of intine development. The primary component of the intine layer is pectin, which plays an essential role in the polar growth of pollen tubes. Demethylesterified pectin is mainly distributed in the shank region of the pollen tube, which can maintain the hardness of the pollen tube wall. Methylesterified pectin is mainly located in the top region, which is beneficial for improving the plasticity of the pollen tube top. In this review, we summarize the developmental process of the anther, pollen and pollen wall in Arabidopsis; furthermore, we describe the research progress on the pollen wall formation pattern and its molecular mechanisms in detail.

2.
Soft Matter ; 17(8): 2191-2204, 2021 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-33459746

RESUMO

An intrinsic self-healing polyurethane (PU) elastomer with excellent self-healing efficiency was prepared. The self-healing properties of this elastomer as well as the temperature dependence of self-healing can be tailored by regulating the molar ratio of hard to soft segments. The self-healing efficiency of 92.5% is the highest when the molar ratio of 4,4-methylenedicyclohexyl diisocyanate (HMDI) to polypropylene carbonate polyol (PPC) is 1.3 and the temperature is 25 °C. In situ temperature swing infrared spectra and low-field nuclear magnetic resonance reveal that the soft segment, PPC, endows PU with a dense dynamic hydrogen bond network, and the dissociation and reconstruction of the hydrogen bond network enable the PU to heal. To date, the exchange of hydrogen bonds has not been observed intuitively through experimental means. Therefore, the number, type, strength, lifetime, and the exchange of hydrogen bonds in the self-healing process at different temperatures were investigated by molecular dynamics (MD) simulation. The simulated results show that the type of hydrogen bond exchange between functional groups will be affected by temperature. The hydrogen bonds between urethane and urea groups play a leading role in the self-healing properties due to the high strength and a large number of hydrogen bonds at both 25 and 50 °C. The stronger strength, longer lifetime, and greater number of effective hydrogen bonds at 25 °C make the self-healing efficiency of PU higher than at 50 °C.

3.
Int J Neurosci ; 131(1): 85-94, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32148137

RESUMO

Objective: Neuroinflammation is a central part of cerebral ischemia/reperfusion injury. The novel immune suppressant, fingolimod, is a promising candidate to ameliorate stroke-induced damage. Fingolimod is efficacious in experimental ischemic models, but a rigorous meta-analysis is lacking that considers how different experiment variables affect outcomes.Methods: We conducted a systematic literature review of fingolimod in stroke models, with the aim of rigorously evaluating fingolimod's effects on reducing infarct volume improving neurological outcomes. Seventeen variables were evaluated as covariates for the source of heterogeneity, and effect sizes were combined by using normalized mean difference meta-analysis to evaluate efficacy. Study quality was evaluated by the CAMARADES ten-item checklist, and publication bias was evaluated by funnel plots and Egger's tests.Results: About 123 unduplicated articles were identified in the literature research. Of these papers, 118 articles were excluded after reading titles and abstracts. Another 17 articles were selected in this study. Study quality was moderate (median = 6; interquartile range = 4), and publication bias was statistically insignificant. fingolimod reduced infarct volume by 30.4% (95% CI 22.4%-38.3%; n = 24; I2 = 90.0%; p < 0.0001) and consistently enhanced neurobehavioral outcome by 34.2% (95% CI 23.1%-45.2%; n = 14; I2 = 76.5%; p < 0.0001). No single factors accounted for heterogeneity.Conclusions: Our rigorous statistical evaluation confirmed the neuroprotective properties of fingolimod. New data can be used in designing future clinical trials.

4.
Physiol Plant ; 2020 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-33247451

RESUMO

Chalcone synthase (CHS) is the key enzyme in the flavonoid biosynthetic pathway and has been studied in many plants, but the function of the CHS gene has not been well characterized in Paeonia ostii. In this study, we obtained a CHS homolog gene from P. ostii, which possessed the putative conserved amino acids of chalcone synthase by multiple alignment analysis and demonstrated the highest expression in developing seeds. In vitro assays of the recombinant PoCHS protein confirmed enzymatic activity using malonyl-CoA and 4-coumaroyl-CoA as substrates, and the optimal pH and reaction temperature were 7.5 and 40 °C, respectively. Furthermore, ectopic over-expression of PoCHS in Arabidopsis up-regulated the expression levels of genes involved in seed development (ABI), glycolysis (PKp2, PDH-E1a, and SUS2/3), and especially fatty acid biosynthesis (BCCP2, CAC2, CDS2, FatA, and FAD3). This resulted in an increased unsaturated fatty acid content, especially α-linolenic acid, in transgenic Arabidopsis seeds. In this study, we examined the functions of CHS homolog of P. ostii and demonstrated its new function in seed fatty acid biosynthesis.

5.
Curr Med Chem ; 2020 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-33200693

RESUMO

Atherosclerosis is a chronic arterial wall illness that forms atherosclerotic plaques within the arteries. Plaque formation and endothelial dysfunction are atherosclerosis' characteristics. It is believed that the occurrence and development of atherosclerosis mainly include endothelial cell damage, lipoprotein deposition, inflammation and fibrous cap formation, but its molecular mechanism has not been elucidated. Therefore, protecting the vascular endothelium from damage is one of the key factors against atherosclerosis. The factors and processes involved in vascular endothelial injury are complex. Finding out the key factors and mechanisms of atherosclerosis caused by vascular endothelial injury is an important target for reversing and preventing atherosclerosis. Changes in cell adhesion are the early characteristics of EndMT, and cell adhesion is related to vascular endothelial injuryand atherosclerosis. Recent researches have exhibited that endothelial-mesenchymal transition (EndMT) can urge atherosclerosis' progress, and it is expected that inhibition of EndMT will be an object for antiatherosclerosis. We speculate whether inhibition of EndMT can become an effective target for reversing atherosclerosis by improving cell adhesion changes and vascular endothelial injury. Studies have shown that H2S has a strong cardiovascular protective effect. Because H2S has anti-inflammatory, anti-oxidant, inhibiting foam cell formation, regulating ion channels and enhancing cell adhesion and endothelial functions, the current research on H2S in cardiovascular aspects is increasing. but anti-atherosclerosis' molecular mechanism and the function of H2S in EndMT have not been explicit. In order to explore the mechanism of H2S against atherosclerosis, to find an effective target to reverse atherosclerosis, we sum up the progress of EndMT promoting atherosclerosis, and Hydrogen sulfide's potential anti-EndMT effect is discussed in this review.

6.
ESC Heart Fail ; 2020 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-32954647

RESUMO

AIMS: Qishen Yiqi dripping pills (QSYQ) may be beneficial in patients with ischaemic heart failure (IHF). We aimed to assess the efficacy and safety of QSYQ administered together with guideline-directed medical therapy in patients with IHF. METHODS AND RESULTS: This prospective randomized, double-blind, multicentre placebo-controlled study enrolled 640 patients with IHF between March 2012 and August 2014. Patients were randomly assigned to receive 6 months of QSYQ or placebo in addition to standard treatment. The primary outcome was 6 min walking distance at 6 months. Among the 638 IHF patients (mean age 65 years, 72% men), the 6 min walking distance increased from 336.15 ± 100.84 to 374.47 ± 103.09 m at 6 months in the QSYQ group, compared with 334.40 ± 100.27 to 340.71 ± 104.57 m in the placebo group (mean change +38.32 vs. +6.31 m respectively; P < 0.001). The secondary outcomes in composite clinical events, including all-cause mortality and emergency treatment/hospitalization due to heart failure, were non-significantly lower at 6 months with QSYQ compared with placebo (13% vs. 17%; P = 0.45), and the change of brain natriuretic peptide was non-significantly greater with QSYQ compared with placebo (median change -14.55 vs. -12.30 pg/mL, respectively; P = 0.21). By contrast, the Minnesota Living with Heart Failure Questionnaire score significantly improved with QSYQ compared with placebo (-11.78 vs. -9.17; P = 0.004). Adverse events were minor and infrequent with QSYQ, similar to the placebo group. CONCLUSIONS: Treatment with QSYQ for 6 months in addition to standard therapy improved exercise tolerance of IHF patients and was well tolerated.

7.
Front Plant Sci ; 11: 574316, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32983222

RESUMO

Arabidopsis thaliana ENO2 (AtENO2) encodes two proteins AtENO2 (enolase) and AtMBP-1 (c-Myc binding protein 1-like). The loss of AtENO2 function causes the constitutive developmental defects which are correlated with reduced enolase activity, but not AtMBP-1 transcript abundance. However, the regulation mechanism of AtENO2 on the seed properties is still not clear. In this study, we found that the mutation of AtENO2 reduced the seed size and weight. The level of glucose in seed was significantly elevated but that of starch was decreased in AtENO2 mutants compared to WT plants. We also found that AtENO2 mutation reduced the content of cytokinin which resulted in smaller cotyledons. The RNA-seq data showed that there were 1892 differentially expressed genes and secondary metabolic pathways were significantly enriched. Instead of AtMBP-1, AtENO2 protein interacted with AtbZIP75 which may mediate the secondary metabolism. Therefore, ENO2 alters the size and weight of seeds which is not only regulated by the content of cytokinin and secondary metabolism, but may be affected by the interaction of ENO2 and bZIP57. These results are helpful to understand the novel function of AtENO2 which provide a foundation for further exploration of the key candidate genes for crop breeding.

8.
ACS Omega ; 5(35): 22140-22156, 2020 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-32923772

RESUMO

The biomarker features of 10 Chang 7 crude oil samples were investigated by gas chromatography-mass spectrometry (GC-MS), and the rare-earth element (REE) compositions of 16 Chang 7 and Chang 8 crude oil samples were determined by inductively coupled plasma-mass spectrometry (ICP-MS) for the first time in Longdong area. Oil-source correlation analysis was improved by biomarkers and REEs. The distribution and relative ratios of a series of biomarker parameters in saturated hydrocarbons and aromatic hydrocarbons of crude oil samples indicate that Chang 7 tight oil has already reached the mature stage. The organic matter mainly comes from lower aquatic organisms of algae, with some contribution of micro-organisms and bacteria, while the forming environment of tight oil is mainly the transitional environment of sub-oxidizing to sub-reducing. The V/(V + Ni) and Ni/Co ratios of crude oil samples suggest that the specific redox conditions of Chang 71 and Chang 72 samples were slightly oxic, while Chang 73 and Chang 8 samples were formed under an anoxic environment. The results of both biomarker-based and REE-based oil-source correlation analysis indicate that Chang 71 and Chang 72 tight oils come from Chang 7 mudstone, while most of the Chang 73 tight oils are from Chang 7 oil shale, with part of mixed from Chang 7 mudstone. This recognition may indicate that Chang 7 mudstone and oil shale are two relatively independent hydrocarbon self-generation and near-storage systems. The analysis results demonstrate that the REE composition in crude oil is an efficient and accurate tool for oil-source correlation in the petroleum system.

9.
PLoS One ; 15(9): e0238294, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32870940

RESUMO

The proposed method is to do simplification for Digital Elevation Model (DEM), which uses a few of original nodes representing the terrain surface while maintaining the accuracy. The original DEM nodes are sampled using the Maximal Poisson-disk Sampling (MPS), in which, the disk's size of each sample is computed on basis of the Singular Value Decomposition (SVD). MPS can generate the hyper-uniformly distributed samples and was taken to do DEM adaptive sampling by being combined with the geodesic metric. However, the geodesic distance computation is complex and the requirement for memory is high. As such, this paper proposes an extension of the classic MPS based method for selecting quasi-randomly distributed points from DEM nodes based on the distribution of eigenvalues, accounting for surface heterogeneity. To achieve this objective, uniform MPS is conducted to sample the DEM nodes by setting the related disk radius to be inversely proportional to the local terrain complexity, which is defined as an index expressing the local terrain variation. Then, the geodesic metric related parameters are implicitly contained in the defined index. As a result, more samples are concentrated in the rugged regions, and vice versa. The proposed method shows better perfermance, at least the results are comparable with the geodesic distance based Poisson disk sampling method. Meanwhile, it greatly accelerates the sampling process and reduces the memory cost.


Assuntos
Algoritmos , Aumento da Imagem/métodos , Fotogrametria
10.
Opt Express ; 28(16): 23320-23328, 2020 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-32752330

RESUMO

High-density Si nanocrystal thin film composed of Si nanocrystals and SiO2, or Si-NCs:SiO2, was prepared by annealing hydrogen silsesquioxane (HSQ) in a hydrogen and nitrogen (H2:N2=5%:95%) atmosphere at 1100°C. Conventional normal-pressure (1-bar) hydrogenation failed to enhance the light emission of the Si-NCs:SiO2 sample made from HSQ. High-pressure hydrogenation was then applied to the sample in a 30-bar hydrogen atmosphere for this purpose. The light emission of Si-NCs increased steadily with increasing hydrogenation time. The photoluminescence (PL) intensity, the PL quantum yield, the maximal electroluminescence intensity, and the optical gain were increased by 90%, 114%, 193% and 77%, respectively, after 10-day high-pressure hydrogenation, with the PL quantum yield as high as 59%, under the current experimental condition.

11.
Phys Chem Chem Phys ; 22(31): 17620-17631, 2020 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-32720967

RESUMO

An intrinsic self-healing polyurethane (PU) elastomer was synthesized in our previous work. In this work, three-dimensional (3D) micro-crack models based on experimental samples were further introduced to investigate their self-healing behavior, mechanism, and temperature dependence by molecular dynamics (MD) simulations. In particular, the number, type, strength, and lifetime of hydrogen bonds as well as the microscopic behavior of molecular diffusion in the self-healing process were investigated. It was found that the self-healing capacity of PU mainly results from intermolecular electrostatic interactions, and the hydrogen bond plays a key role in electrostatic interactions. There is an optimum ratio of soft and hard segments at which the number of hydrogen bonds is appropriate and the self-healing capacity is optimum. Besides, the temperature has an optimal value at which the self-healing rate of PU is the fastest. The exchanges of hydrogen bonds, which endowed PU with self-healing capacity, were further revealed intuitively. We found that the exchanges of hydrogen bonds are reversible and more likely to occur on the urethane groups. This study deepened the understanding of the self-healing character of PU at the molecular level.

12.
Med Sci Monit ; 26: e924593, 2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32667287

RESUMO

BACKGROUND Since venous drainage in acute arterial ischemic stroke has not been thoroughly researched, we evaluate the effect of argatroban, a selective direct thrombin inhibitor, as a therapy to increase the rate of basal vein Rosenthal (BVR) drainage and improve patients' post-stroke outcomes. MATERIAL AND METHODS In this multicenter clinical trial, 60 eligible patients at 4.5 to 48 hours after the stroke onset were recruited. After being randomly allocated into 2 groups, they were treated with standard therapy either alone or with argatroban. RESULTS Compared to the contralateral brain hemisphere, the mean flow velocity (MFV) in BVR drainage was significantly reduced in the stroke-afflicted ipsilateral hemisphere. After treatment with argatroban for 7 days, the MFV from BVR of the ipsilateral hemisphere in the argatroban treated group was significantly increased when compared to the control group. At 90 days after the onset of stroke, the MFV of BVR in the ipsilateral hemisphere was similar in both groups. Compared with controls, the argatroban-treated patients had smaller lesions from baseline to 7 days. Argatroban also improved National Institutes of Health Stroke Scale (NIHSS) scores on day 7 after the onset of stroke. Furthermore, the argatroban group's neurological functions were superior to those of their untreated counterparts after 90 days. No difference was found in the incidence of adverse reactions between the 2 groups. CONCLUSIONS These observations indicate that vein drainage change may contribute to the acute phase of brain edema and the outcomes of ischemic stroke patients.

13.
Pestic Biochem Physiol ; 168: 104618, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32711759

RESUMO

The carmine spider mite, Tetranychus cinnabarinus (Boisduval), is a polyphagous agricultural pest with an extensive host plant range. Scopoletin is a promising acaricidal compound whose acaricidal mechanism may occur by disrupting intracellular Ca2+ homeostasis and calcium signaling pathways. However, the underlying mechanism of scopoletin for specific target locations of T. cinnabarinus remains unclear. In this study, a full-length cDNA of the L-type voltage-gated calcium channel (TcLTCC) subunit gene from T. cinnabarinus was cloned and characterized. The expression pattern of the TcLTCC gene in all developmental stages of T. cinnabarinus was analyzed. The gene was highly expressed in larval and nymphal stages and was significantly upregulated after treatment with scopoletin. Knocking down the TcLTCC transcript reduced the sensitivity of T. cinnabarinus to scopoletin. Homology modeling and molecular docking were also conducted. The interaction between scopoletin and TcLTCC showed that scopoletin inserted into the cavity bound to the site of the TcLTCC protein by the driving force of hydrogen bonding. This study provides insights into the mechanism by which scopoletin interacts with TcLTCC. Results can improve the understanding of the toxicity of scopoletin to T. cinnabarinus and provide valuable information for the design of new LTCC inhibitors.


Assuntos
Acaricidas , Tetranychidae , Animais , Cálcio , Simulação de Acoplamento Molecular , Escopoletina
14.
Chem Commun (Camb) ; 56(56): 7813-7816, 2020 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-32602495

RESUMO

An effective and regioselective strategy for trifluoromethylation and perfluoroalkylation of isoquinolines and heteroarenes was developed. By combination of TMSCnF2n+1 (n = 1, 2, 3) with PIFA, the method achieved the corresponding perfluoroalkylated products with broad functional group tolerance.

15.
Biosci Biotechnol Biochem ; 84(7): 1353-1361, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32290769

RESUMO

MiR-181a-5p's mechanism in hypoxia-reoxygenation (H/R)-induced cardiomyocytes apoptosis has not been clarified. This study verified that SIRT1 was the target of miR-181a-5p. MiR-181a-5p expression was up-regulated or down-regulated in H/R-induced cardiomyocytes, and SIRT1 was transfected into cells alone or in combination with miR-181a-5p. Cell viability, apoptosis, levels of released lactate dehydrogenase (LDH), malondialdehyde (MDA), and superoxide dismutase (SOD), as well as the Bcl-2, Bax, and Caspase 3 levels in treated cells were tested. On the one hand, down-regulated miR-181a-5p promoted cell viability, reduced released LDH and MDA, and increased SOD level in H/R-induced cardiomyocytes. On the other hand, miR-181a-5p inhibited apoptosis and elevated Bcl-2 expression while decreasing the expressions of Bax and Caspase 3 in treated cells, but the effects of miR-181a-5p could be rescued by SIRT1. In conclusion, miR-181a-5p involved in H/R-induced cardiomyocytes apoptosis through regulating SIRT1, which might become a novel direction for related diseases.

16.
Nat Commun ; 11(1): 914, 2020 02 14.
Artigo em Inglês | MEDLINE | ID: mdl-32060269

RESUMO

The Baeyer-Villiger reaction is used extensively in organic chemistry. Sila- and bora-variants have also been documented widely, with these processes underpinning, for example, the Fleming-Tamao oxidation and hydroborative alkene hydration, respectively. By contrast, the development of thia-Baeyer-Villiger reactions involving sulfoxides has long been considered unlikely because competitive oxidation to the sulfone occurs exclusively. Here, we disclose a photoinduced thia-Baeyer-Villiger-type oxidations; specifically, we find that exposure of dibenzothiophene (DBT) derivatives to an iron porphyrin catalyst under Ultraviolet irradiation in the presence of t-BuOOH generates sulfinic esters in up to 87% yield. The produced sulfinic esters are transformed to a variety of biphenyl substrates including biphenyl sulfoxides, sulfones and sulfonamides in 1-2 steps. These results provide a mild process for the selective functionalization of sulfur compounds, and offer a biomimetic approach to convert DBT into 2-hydroxybiphenyl under controllable stepwise pathway. Based upon experimental evidences and DFT calculation, a mechanism is proposed.

17.
Eur Arch Otorhinolaryngol ; 277(4): 1089-1094, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32020313

RESUMO

PURPOSE: To explore the application value of continuous suture of the inferior turbinate in inferior turbinate submucosal bone resection. METHODS: Twenty patients with chronic hypertrophic rhinitis with or without nasal septum deviation underwent inferior turbinate submucosal bone resection with or without septoplasty. The inferior turbinate was continuously sutured with or without nasal septum suture after surgery. The nasal cavity was not packed. The postoperative clinical outcome was evaluated using visual analog scales (VASs), saccharin test, nasal endoscopy, and nasal resistance test. Postoperative complications were recorded. RESULTS: All 20 endoscopic surgeries were successfully performed. One day after surgery, the VAS scores of nasal pain (1.3 ± 0.5), headache (0.8 ± 0.4), tearing (0.3 ± 0.3), and bleeding (0.3 ± 0.3) in patients were low; 1 week after surgery, the nasal mucociliary transport time was not significantly prolonged compared to that before surgery (P > 0.05); 1 month after surgery, the symptoms of nasal congestion had improved significantly, as the VAS score for nasal congestion was lower than that before surgery (P < 0.05); the volume of the hypertrophied inferior turbinate of all patients was reduced, the mucous membrane was smooth and rosy, the nasal septum was centrally located, and the total nasal resistance values at 150 Pa pressure had returned to the normal reference range (0.282 ± 0.103 Pa/cm3/s); no complications such as bleeding, nasal infection, nasal dryness, and olfactory disorders occurred. CONCLUSION: After inferior turbinate submucosal bone resection with or without septoplasty, inferior turbinate continuous suture with or without nasal septum suture instead of nasal packing can significantly improve postoperative discomfort, improve nasal ventilation, protect nasal function, and accelerate postoperative recovery.

18.
Interface Focus ; 10(1): 20190086, 2020 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-31897295

RESUMO

Recent developments in both biological data acquisition and analysis provide new opportunities for data-driven modelling of the health state of an organism. In this paper, we explore the evolution of temperature patterns generated by telemetry data collected from healthy and infected mice. We investigate several techniques to visualize and identify anomalies in temperature time series as temperature relates to the onset of infectious disease. Visualization tools such as Laplacian Eigenmaps and Multidimensional Scaling allow one to gain an understanding of a dataset as a whole. Anomaly detection tools for nonlinear time series modelling, such as Radial Basis Functions and Multivariate State Estimation Technique, allow one to build models representing a healthy state in individuals. We illustrate these methods on an experimental dataset of 306 Collaborative Cross mice challenged with Salmonella typhimurium and show how interruption in circadian patterns and severity of infection can be revealed directly from these time series within 3 days of the infection event.

19.
Am J Physiol Endocrinol Metab ; 318(4): E441-E452, 2020 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-31935111

RESUMO

During pregnancy, the uterus transitions from a quiescent state to an excitable, highly contractile state to deliver the fetus. Two important contributors essential for this transition are hormones and ion channels, both of which modulate myometrial smooth muscle cell (MSMC) excitability. Recently, the sodium (Na+) leak channel, nonselective (NALCN), was shown to contribute to a Na+ leak current in human MSMCs, and mice lacking NALCN in the uterus had dysfunctional labor. Microarray data suggested that the proquiescent hormone progesterone (P4) and the procontractile hormone estrogen (E2) regulated this channel. Here, we sought to determine whether P4 and E2 directly regulate NALCN. In human MSMCs, we found that NALCN mRNA expression decreased by 2.3-fold in the presence of E2 and increased by 5.6-fold in the presence of P4. Similarly, E2 treatment decreased, and P4 treatment restored NALCN protein expression. Additionally, E2 significantly inhibited, and P4 significantly enhanced an NALCN-dependent leak current in MSMCs. Finally, we identified estrogen response and progesterone response elements (EREs and PREs) in the NALCN promoter. With the use of luciferase assays, we showed that the PREs, but not the ERE, contributed to regulation of NALCN expression. Our findings reveal a new mechanism by which NALCN is regulated in the myometrium and suggest a novel role for NALCN in pregnancy.


Assuntos
Estradiol/farmacologia , Canais Iônicos/biossíntese , Canais Iônicos/genética , Proteínas de Membrana/biossíntese , Proteínas de Membrana/genética , Miócitos de Músculo Liso/metabolismo , Miométrio/metabolismo , Progesterona/farmacologia , Adulto , Linhagem Celular , Feminino , Humanos , Mutação/genética , Miócitos de Músculo Liso/efeitos dos fármacos , Miométrio/efeitos dos fármacos , Gravidez , RNA Mensageiro/biossíntese , Elementos de Resposta/efeitos dos fármacos
20.
Br J Dev Psychol ; 38(2): 304-318, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-31960469

RESUMO

Previous studies have shown that reinstatement of spatial and temporal background information during learning can promote memory retention in adults. However, the effect in children is unclear. In order to explore the effect of episodic context reinstatement on the memory retention of different age groups, first-grade students, third-grade students, and third-year college students studied two word lists. When the words were presented mixed together, the participants were told to either restudy the words under intentional learning conditions or make list discrimination judgements by indicating the list from which each word had originated. Results revealed that the retrieval practice based on the episodic context reinstatement paradigm showed a phased development trend in the participants compared to restudy. Episodic context reinstatement only promoted memory retention in the third-grade children and college students, but not in the first-grade children. During the early elementary school years, children do not have relatively mature episodic memory ability and cannot output memories according to context clues. Our finding suggests important guidance for the age-appropriate use of tests as instructional tools in basic education. Statement of contribution What is already known on this subject? One recent theory of retrieval-based learning is the episodic context account; it promotes memory retention by reinstate the context of a prior learning episode. Previous studies have confirmed in the adults that the episodic context reinstatement was the main reason for retrieval practice to promote memory retention through the list discrimination tasks What does this study add? This study revealed that the retrieval practice based on the episodic context reinstatement paradigm showed a phased development trend in the participants. Episodic context reinstatement only promoted memory retention in the third-grade children and college students, but not in the first-grade children, and the results support the episodic context assumption, namely that episodic context reinstatement is the key factor in memory retention. The results of this study can explain why most prior work has observed the effect of retrieval practice in the groups above grade three.

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