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1.
Org Lett ; 2020 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-32149521

RESUMO

Density functional theory mechanistic study of the nickel-catalyzed reductive alkyne-alkyne cyclodimerization with CH3OH/BEt3 unveils that, after forming a nickel-alkyne π complex, the reaction prefers outer-sphere proton transfer rather than the common alkyne-alkyne oxidative cyclization. The outperformance of aminophosphine ligand (L1) is attributed to its bidentate coordination that favors the proton transfer, the labile -NH2 and strong electron-donating -PPh2 arms and adequate Ni-P distance that allow the hydrogen transfer of the ethyl group of MeO-BEt3-.

2.
Artigo em Inglês | MEDLINE | ID: mdl-32162219

RESUMO

Pardosa pseudoannulata (Araneae: Lycosidae), as an important predator of crop pests, has served as a strong driver for ecological regulation of pests. Cadmium (Cd) is a toxic heavy metal widely distributed in the soil in China, which not only seriously pollutes the ecological environment, but also poses a great threat to the survival of organisms. Palpal bulbs are the genital organs of male spiders, playing an important role in reproductive physiology. However, the effects of long-term Cd stress on the genital organ of the primary pest predator were poorly understood. Therefore, we investigated the Cd effect on the male palpal organ of P. pseudoannulata at morphological and gene expression levels. The results showed that no obvious difference in the morphology between the Cd-treated and control groups was observed, but cell adhesion was affected at molecular level. Transcriptome sequencing analysis revealed that under long-term Cd stress, the biological processes including cell-cell adhesion via plasma-membrane adhesion molecules, cell-cell adhesion, and homophilic cell adhesion via plasma membrane adhesion molecules were the top three differentially expressed terms (p-adj < 0.001), and 51 unigenes were annotated into cadherin-related proteins, such as protocadherin, cadherin-87A, and cadherin-96Ca, among which, 18 unigenes were significantly upregulated under the Cd stress. Our outcomes indicate that the differentially expressed genes involved in cell adhesion may explain the negative effects of Cd stress on the spider genital organ, and the comprehensive transcriptome dataset will also provide a profound molecular information of the genital organ of P. pseudoannulata.

3.
Drug Resist Updat ; 50: 100683, 2020 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-32146422

RESUMO

Chemoresistance including intrinsic and acquired anticancer drug resistance continues to be a primary hindrance towards curative cancer treatment. Therefore, deciphering the underlying molecular mechanisms is of paramount importance required towards the overcoming of chemoresistance. Cumulative evidence revealed that long non-coding RNAs (lncRNAs) play a pivotal role in conferring anticancer drug resistance upon a broad spectrum of cancers. Hence, numerous lncRNAs are recognized as novel biomarkers and therapeutic targets in the diagnosis and treatment of malignancies, which urges us to comprehensively delineate the critical functions of lncRNAs in chemoresistance. In this respect, we herein succinctly elucidate the molecular mechanisms by which lncRNAs modulate their downstream targets to mediate cancer chemoresistance. Therefore, the current review may provide a significant basis for the future conquering of chemoresistance via targeting lncRNAs in cancer therapeutics.

4.
Sci Rep ; 10(1): 4383, 2020 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-32127630

RESUMO

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

5.
J Cell Mol Med ; 2020 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-32163656

RESUMO

Vascular dysfunction resulting from diabetes is an important factor in arteriosclerosis. Previous studies have shown that during hyperglycaemia and diabetes, AKAP150 promotes vascular tone enhancement by intensifying the remodelling of the BK channel. However, the interaction between AKAP150 and the BK channel remains open to discussion. In this study, we investigated the regulation of impaired BK channel-mediated vascular dysfunction in diabetes mellitus. Using AKAP150 null mice (AKAP150-/- ) and wild-type (WT) control mice (C57BL/6J), diabetes was induced by intraperitoneal injection of streptozotocin. We found that knockout of AKAP150 reversed vascular remodelling and fibrosis in mice with diabetes and in AKAP150-/- diabetic mice. Impaired Akt/GSK3ß signalling contributed to decreased BK-ß1 expression in aortas from diabetic mice, and the silencing of AKAP150 increased Akt phosphorylation and BK-ß1 expression in MOVAS cells treated with HG medium. The inhibition of Akt activity caused a decrease in BK-ß1 expression, and treatment with AKAP150 siRNA suppressed GSK3ß expression in the nuclei of MOVAS cells treated with HG. Knockout of AKAP150 reverses impaired BK channel-mediated vascular dysfunction through the Akt/GSK3ß signalling pathway in diabetes mellitus.

6.
Nanotechnology ; 2020 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-32163939

RESUMO

High quality and high quantity few-layer graphene was successfully prepared by a new impinging jets method. Natural graphite flakes were first agitated in N-Methyl Pyrrolidone with the assistance of supercritical CO2, then the half-exfoliated graphite was further stripped by the shear stress derived from the impinging jets. After the energy conversion and the stress analysis of the graphite particle during the whole exfoliation process, it revealed that the size of target mesh, the distance between the nozzle and the target, the decompression rate and the raw materials size have a significant influence on the exfoliation process. Additionally, a microscopic view of the exfoliation and dispersion mechanism of graphene in CO2-NMP was investigated by molecular dynamic simulation, CO2 was found to be beneficial for the penetration of NMP into the graphite sheets. Finally, the concentration and quality characteristics of the prepared graphene were characterized by ultraviolet-visible spectroscopy, transmission electron microscopy, raman spectroscopy and atomic force microscope. The maximum concentration was as high as 0.689mg/mL, the thickness of 68% of the product was less than 2.5nm, and the lateral dimension was from 0.5-3.0µm. These results indicated that the method was promising in large-scale industrial production.

7.
J Am Chem Soc ; 2020 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-32126754

RESUMO

Because of the typical instability of copper nanoclusters, atom-precise structural elucidation of these nanoclusters has remained elusive. Herein, we report an air- and moisture-stable 23-copper nanocluster (SD/Cu23a or SD/Cu23b) isolated from the reaction of Cu(CF3COO)2, tBuC≡CH, Cu powder, and Ph2SiH2 using a gradient reduction (CuII → CuI → Cu0) strategy (GRS), which is competent for controlling the kinetics of the reduction reaction, thus avoiding formation of pure CuI complexes or large Cu0 nanoparticles. The solid-state structure of the Cu23 nanocluster shows a rare [Cu4]0 tetrahedral kernel surrounded by an outer Cu19 shell, which is protected by tBuC≡C- and CF3COO- ligands. The Cu23nanocluster is a rare four-electron superatom with a 1S21P2 electronic shell closure and can be crystallized in two polymorphs (R3c and R3̅) depending on the solvent used. The crystallization of SD/Cu23a in the R3c space group is mainly governed by van der Waals forces and C-H···F interactions, whereas additional intermolecular C-H···Clchloroform interactions are responsible for the R3̅ space group of SD/Cu23b. This work not only shows the ingenuity of a gradient reduction strategy for the synthesis of copper nanoclusters but also provides a better fundamental understanding of how to produce the polymorphic copper nanoclusters in a precisely tunable fashion.

8.
Curr Biol ; 2020 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-32169207

RESUMO

Auxin and brassinosteroids (BR) are crucial growth regulators and display overlapping functions during plant development. Here, we reveal an alternative phytohormone crosstalk mechanism, revealing that BR signaling controls PIN-LIKES (PILS)-dependent nuclear abundance of auxin. We performed a forward genetic screen for imperial pils (imp) mutants that enhance the overexpression phenotypes of PILS5 putative intracellular auxin transport facilitator. Here, we report that the imp1 mutant is defective in the BR-receptor BRASSINOSTEROID INSENSITIVE 1 (BRI1). Our set of data reveals that BR signaling transcriptionally and post-translationally represses the accumulation of PILS proteins at the endoplasmic reticulum, thereby increasing nuclear abundance and signaling of auxin. We demonstrate that this alternative phytohormonal crosstalk mechanism integrates BR signaling into auxin-dependent organ growth rates and likely has widespread importance for plant development.

9.
Zhongguo Yi Xue Ke Xue Yuan Xue Bao ; 42(1): 67-72, 2020 Feb 28.
Artigo em Chinês | MEDLINE | ID: mdl-32131942

RESUMO

Objective To evaluate the relationship of volumetric changes and endoleaks after endovascular aneurysm repair(EVAR)for abdominal aortic aneurysms(AAAs). Methods We retrospectively evaluated the clinical and imaging data of 54 patients who had underwent EVAR within 1 month after their aneurysms were detected.All patients received abdominal and pelvic enhanced computed tomography(CTA)for two follow-up visits in Peking Union Medical College Hospital from July 2014 to February 2019.Three-dimensional volumes and maximum diameters on axial CT of the aortic aneurysms were calculated by dedicated semi-automated 3D segmentation software before surgery(V0 and D0),in the 4 th postoperative month(V1and D1),and in the 12 th postoperative month(V2and D2),respectively.The presence or absence of endoleak for each patient with the V1/V0,V2/V0,and V2/V1 were calculated to assess the significance of volume changes with respect to endoleaks and the correlation between volume changes and maximum diameter changes on axial CT images. Results Of the 54 patients,endoleaks were found in 11 patients at the first follow-up visit(4 months after surgery),among whom 8 patients were arranged a second follow-up visit(12 months after surgery),during which endoleaks were found in 5 patients.Fifteen of 43 non-leaked patients underwent a second CTA examination,which revealed endoleak in one case.Patients who did exhibit endoleaks[n =11,V1/V0=1.086(1.033,1.116)]showed significant increases in aneurysm volume when compared with those who did not exhbit endoleaks[n =43,V1/V0=1.019(0.970,1.065)]at the first follow-up visit(Z=-2.695,P=0.007),although no significant difference was found with regard to volume changes between endoleaks(n=6,V2/V0=1.1±0.2,V2/V1=1.0±0.1)and non-endoleaks(n=17,V2/V0=1.0±0.1,V2/V1=1.0±0.1)at the second follow-up visit(t=0.725,P=0.476)as well as between these two follow-up visits(t=-0.021,P=0.984).V0 and D0 were moderately correlated with V1 and D1,respectively(r=0.5,P<0.001)and strongly correlated with V2 and D2,respectively(r=0.8,P<0.001).V1 and D1 were strongly correlated with V2 and D2,respectively(r=0.8,P<0.001). Conclusions The changes of aneurysm volume cannot reliably reflect the occurrence of endoleaks.The change of maximum axial diameter of aneurysm has certain correlation with the changes of aneurysm volume.

10.
Biomed Environ Sci ; 33(2): 133-137, 2020 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-32131960

RESUMO

This study aimed to examine the association between famine exposure in different stages of life and the risk of overweight/obesity and abdominal obesity in laterlife. A total of 12,458 participants were categorized into non-exposure and four direct exposures, including fetal, childhood, adolescence, and adult exposure. Only risk of being overweight or obesity in adolescence exposure [odds ratio ( OR), 1.45; 95% confidence interval ( CI), 1.08-1.94] was significantly higher than in non-exposure. Childhood ( OR, 1.27; 95% CI, 1.05-1.54) and adolescence ( OR, 1.53; 95% CI, 1.15-2.05) exposures had significantly an increased risk of abdominal obesity compared with non-exposure. Additionally, different famine severity exposures had different influences on the development of overweight/obesity and abdominal obesity. Famine exposure in adolescence, which was a behavior formative period, can increase the risk of overweight/obesity and abdominal obesity in adulthood, specifically in famine severely affect area.

11.
Small ; : e1907645, 2020 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-32141157

RESUMO

Polyanion-type phosphate materials are highly promising cathode candidates for next-generation batteries due to their excellent structural stability during cycling; however, their poor conductivity has impeded their development. Isostructural and multivalent anion substitution combined with carbon coating is proposed to greatly improve the electrochemical properties of phosphate cathode in sodium-ion batteries (SIBs). Specifically, multivalent tetrahedral SiO4 4- substitute for PO4 3- in Na3 V2 (PO4 )3 (NVP) lattice, preparing the optimal Na3.1 V2 (PO4 )2.9 (SiO4 )0.1 with high-rate capability (delivering a high capacity of 82.5 mAh g-1 even at 20 C) and outstanding cyclic stability (≈98% capacity retention after 500 cycles at 1 C). Theoretical calculation and experimental analyses reveal that the anion-substituted Na3.1 V2 (PO4 )2.9 (SiO4 )0.1 reduces the bandgap of NVP lattice and enhanced its structural stability, Na+ -diffusion kinetics and electronic conductivity. This strategy of multivalent and isostructural anion substitution chemistry provides a new insight to develop advanced phosphate cathodes.

12.
Artigo em Inglês | MEDLINE | ID: mdl-32141988

RESUMO

Nitrate esters have been used in clinical practice for more than one century for the treatment of angina. Their clinical effectiveness is due to vasodilator activity in arteries through a method of delivering nitric oxide (NO), or a NO-like compound. Recently, an increasing numbers of functions of this molecule in biology and pathophysiology have been discovered. Macrophage polarization shift in epicardial adipose tissue (EAT) has been demonstrated to be correlated with the severity of coronary artery disease (CAD). In this study, we aimed to investigate whether nitrate esters could improve coronary atherosclerosis via inhibition of macrophage polarization shift in EAT. A case-control study enrolled 48 subjects in two groups: CAD patients with or without nitrate esters treatment. Infiltration of M1/M2 macrophages and the expressions of pro- and anti-inflammatory cytokines in EAT and subcutaneous white adipose tissue (SWAT) were investigated by immunohistochemical stain among subjects undergoing coronary artery bypass graft surgery. The expression levels of metabolic genes were investigated by real-time PCR. We found that nitrate esters treatment significantly inhibited NF-кB activity and decreased macrophages infiltration and M1/M2 macrophages ratio in EAT in CAD patients. The expressions of pro-inflammatory cytokines were significantly decreased, along with significantly elevated expressions of anti-inflammatory cytokines in CAD patients with nitrate esters treatment, corresponding EAT dysfunction was ameliorated and the severity of CAD patients (Gensini score) was significantly decreased. The protective effects on macrophage polarization and EAT function via NF-кB activity inhibition suggested a potential mechanism of nitrate esters in alleviating the severity of CAD.

13.
Acta Pharmacol Sin ; 2020 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-32112042

RESUMO

Parkinson's disease (PD) is the second most common progressive neurodegenerative disease worldwide. However, there is no available therapy reversing the neurodegenerative process of PD. Based on the loss of dopamine or dopaminergic dysfunction in PD patients, most of the current therapies focus on symptomatic relief to improve patient quality of life. As dopamine replacement treatment remains the most effective symptomatic pharmacotherapy for PD, herein we provide an overview of the current pharmacotherapies, summarize the clinical development status of novel dopaminergic agents, and highlight the challenge and opportunity of emerging preclinical dopaminergic approaches aimed at managing the features and progression of PD.

14.
BMC Plant Biol ; 20(1): 105, 2020 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-32143577

RESUMO

BACKGROUND: "Bairihua", a variety of the Catalpa bungei, has a large amount of flowers and a long flowering period which make it an excellent material for flowering researches in trees. SPL is one of the hub genes that regulate both flowering transition and development. RESULTS: SPL homologues CbuSPL9 was cloned using degenerate primers with RACE. Expression studies during flowering transition in "Bairihua" and ectopic expression in Arabidopsis showed that CbuSPL9 was functional similarly with its Arabidopsis homologues. In the next step, we used Y2H to identify the proteins that could interact with CbuSPL9. HMGA, an architectural transcriptional factor, was identified and cloned for further research. BiFC and BLI showed that CbuSPL9 could form a heterodimer with CbuHMGA in the nucleus. The expression analysis showed that CbuHMGA had a similar expression trend to that of CbuSPL9 during flowering in "Bairihua". Intriguingly, ectopic expression of CbuHMGA in Arabidopsis would lead to aberrant flowers, but did not effect flowering time. CONCLUSIONS: Our results implied a novel pathway that CbuSPL9 regulated flowering development, but not flowering transition, with the participation of CbuHMGA. Further investments need to be done to verify the details of this pathway.

15.
J Am Chem Soc ; 2020 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-32164406

RESUMO

Here we describe an asymmetric [3,3]-sigmatropic rearrangement of aryl iodanes that enables the enantioselective α-arylation of chiral 2-oxazolines, thereby producing valuable chiral α-aryl carbonyl compounds. The success of this protocol hinges on the selective assembly of aryl iodanes with 2-oxazolines and the smooth deprotonation of the in situ-generated iodonium-imine species. The nearly neutral and mild conditions of the reaction allow it to tolerate a wide variety of functional groups. Moreover, the remaining iodine atom in the products not only provides a versatile platform for further elaboration of such molecules but also supplies the asymmetric hypervalent iodine chemistry with a new class of chiral scaffolds.

16.
Environ Pollut ; 262: 114310, 2020 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-32155559

RESUMO

Underwater sound plays an important role in some critical life functions of many aquatic animals. Underwater noise pollution has received relatively more attention in ocean systems. However, little attention has been paid to freshwater systems, such as the Yangtze River which is the habitat of critically endangered Yangtze finless porpoises (Neophocaena asiaeorientalis asiaeorientalis). In 2012, the underwater noise levels in 25 sites along the middle and lower sections of the Yangtze River were measured. The root mean square sound pressure level (SPL) and unweighted sound exposure level (SEL) at each site ranged between 105 ± 2.4 (median ± quartile deviation) and 150 ± 5.5 dB. Obvious spatial and temporal variations in the SPL were detected among the 25 sites. The SPL and SEL in the middle section of the Yangtze River were smaller (approximately 15 dB) and fluctuated more compared to those in the lower section. The power spectrum in the mainstem was site specific. However, all the spectra levels were higher than the audiogram of Yangtze finless porpoises. Majority of the sites had an averaged cumulative unweighted SEL (72%) and cumulative weighted SEL (68%) that surpassed the underwater acoustic thresholds for onset of hearing temporal threshold shifts for finless porpoise. Porpoise bio-sonars were detected in 89% of sonar monitoring sites indicating that noise pollution in the Yangtze River greatly threatened porpoise survival. In 8% of the sites, the averaged cumulative weighted SEL exceeded that of underwater acoustic thresholds causing non-recoverable permanent threshold shifts of finless porpoises auditory system whereas it was less than 1 dB below the underwater acoustic thresholds in other 8% of the sites. These sites urgently needed noise mitigation and management strategies. These results will facilitate the evaluation of the impacts of anthropogenic noise pollution on local finless porpoises and give further guidelines on its effective conservation.

17.
Int J Biochem Cell Biol ; 122: 105741, 2020 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-32173522

RESUMO

The activation of the ß-adrenergic receptor (ß-AR) regulates the human ether a-go-go-related gene (HERG) channel via protein kinase A (PKA), which in turn induces lethal arrhythmia in patients with long QT syndromes (LQTS). However, the role of A-kinase anchoring proteins (AKAPs) in PKA's regulation of the HERG channel and its molecular mechanism are not clear. Here, HEK293 cells were transfected with the HERG gene alone or co-transfected with HERG and AKAP5 using Lipofectamine 2000. Western blotting was performed to determine HERG protein expression, and immunofluorescence and immunoprecipitation were used to assess the binding and cellular colocalization of HERG, AKAP5, and PKA. The HEK293-HERG and HEK293-HERG + AKAP5 cells were treated with forskolin at different concentrations and different time. HERG protein expression significantly increased under all treatment conditions (P < 0.001). The level of HERG protein expression in HEK293-HERG + AKAP5 cells was higher than that observed in HEK293-HERG cells (P < 0.001). Immunofluorescence and immunoprecipitation indicated that HERG bound to PKA and AKAP5 and was colocalized at the cell membrane. The HERG channel protein, AKAP5, and PKA interacted with each other and appeared to form intracellular complexes. These results provide evidence for a novel mechanism which AKAP5 anchors PKA to up-regulate the HERG channel protein.

18.
Int J Mol Sci ; 21(5)2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-32121503

RESUMO

: Catalpa bungei is an economically important tree with high-quality wood and highly valuable to the study of wood formation. In this work, the xylem microstructure of C. bungei tension wood (TW) was observed, and we performed transcriptomics, proteomics and Raman spectroscopy of TW, opposite wood (OW) and normal wood (NW). The results showed that there was no obvious gelatinous layer (G-layer) in the TW of C. bungei and that the secondary wall deposition in the TW was reduced compared with that in the OW and NW. We found that most of the differentially expressed mRNAs and proteins were involved in carbohydrate polysaccharide synthesis. Raman spectroscopy results indicated that the cellulose and pectin content and pectin methylation in the TW were lower than those in the OW and NW, and many genes and proteins involved in the metabolic pathways of cellulose and pectin, such as galacturonosyltransferase (GAUT), polygalacturonase (PG), endoglucanase (CLE) and ß-glucosidase (BGLU) genes, were significantly upregulated in TW. In addition, we found that the MYB2 transcription factor may regulate the pectin degradation genes PG1 and PG3, and ARF, ERF, SBP and MYB1 may be the key transcription factors regulating the synthesis and decomposition of cellulose. In contrast to previous studies on TW with a G-layer, our results revealed a change in metabolism in TW without a G-layer, and we inferred that the change in the pectin type, esterification and cellulose characteristics in the TW of C. bungei may contribute to high tensile stress. These results will enrich the understanding of the mechanism of TW formation.

19.
Chem Commun (Camb) ; 2020 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-32129428

RESUMO

A new general de novo synthesis of pharmaceutically important α-aryl ß-perfluoroalkyl ketones has been disclosed. Compared with trifluoromethylation-initiated radical 1,2-aryl migration of α,α-diaryl allylic alcohols, this protocol employs a new strategy of biomimetic carbene catalysis to assemble alkene, aldehyde and perfluoroalkyl reagents, providing access to products with excellent flexibility of the aryl unit and perfluoroalkyl group. This method also demonstrates excellent functional group compatibility, including some Grignard reagent sensitive groups.

20.
Allergy ; 2020 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-32198890

RESUMO

BACKGROUND: The contribution of B-cell subsets and T-B cell interaction to the pathogenesis of allergic rhinitis (AR) and mechanisms of allergen immunotherapy (AIT) remain poorly understood. This study aimed to outline circulating B-cell signature, the underlying mechanism, and its association with clinical response to AIT in patients with AR. METHODS: IgD/CD27 and CD24/CD38 core gating systems were used to determine frequencies and phenotypes of B cells. Correlations between B cells, T cells, antigen-specific IgE, and disease severity in AR patients were investigated. Switched memory B cells were co-cultured with type 2 follicular helper T (Tfh2) cells and follicular regulatory T (Tfr) cells. Associations between B-cell subsets and clinical benefits of AIT were analyzed. RESULTS: Frequencies and absolute numbers of circulating memory B cells were increased in AR patients. CD23 expression on CD19+ CD20+ CD27+ IgD- switched memory B cells was significantly enhanced and positively correlated with antigen-specific IgE levels, symptom scores, and Tfh2/Tfr cell ratio in AR patients. Compared to those from healthy controls, Tfh2 cells from AR patients had a greater capacity to induce CD23 expression on switched memory B cells via IL-4, which was unable to be sufficiently suppressed by AR-associated Tfr cells with defective IL-10 expression. CD23 expression on switched memory B cells was downregulated after 12-month AIT, which positively associated with disease remission in AR patients. CONCLUSION: T-B cell interaction, bridged by CD23 expression particularly on switched memory B cells, may be involved in the disease pathogenesis and mechanism of AIT in patients with AR.

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