Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 53
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Am J Ophthalmol ; 2020 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-31945334

RESUMO

PURPOSE: To evaluate the anterior chamber angle status and estimate the intraocular pressure (IOP) in patients with mucopolysaccharidoses (MPS) type I, II, IV, and VI. DESIGN: Prospective cross-sectional study METHODS: This study enrolled 27 consecutive MPS patients (8 patients with MPS I, 4 patients with MPS II, 9 patients with MPS IV, and 6 patients with MPS VI) and 20 normal controls. Anterior chamber angle status was evaluated by swept-source optical coherence tomography, and intraocular pressure (IOP) was estimated by the new-generation tonometer Corvis ST. RESULTS: 12 eyes (6 patients) out of the 15 eyes (8 patients) with MPS I had very narrow angles or peripheral iridocorneal touches together with elevated IOP (80%). 6 eyes (3 patients) out of the 8 eyes (4 patients) with MPS II had plateau iris configuration, but all the 8 eyes had normal IOP. All the 18 eyes (9 patients) with MPS IV had normal angle structures, but 8 eyes (4 patients) had elevated IOP (44.4%). 9 eyes (5 patients) out of the 11 eyes (6 patients) with MPS VI had shallow but not closed angles (81.8%). Among these 9 eyes, 5 eyes had elevated IOP, and 4 out of these 5 eyes had IOP above 30 mmHg. The trabecular iris angles of MPS type I, II, VI were smaller than those of MPS type IV and control group. The angle recess areas of MPS type I and VI were smaller than those of MPS type IV and control group. CONCLUSIONS: MPS type I patients are prone to have glaucoma with narrow or closed angle; MPS type II patients tend to have plateau iris; MPS type IV patients are vulnerable to open-angle glaucoma; MPS type VI patients have narrow angles not as close as those of MPS type I. MPS type I, IV, and VI had higher IOP estimates than the control group, but only MPS I and IV had higher corrected IOP estimates than the control group. The ordinary IOP estimates in MPS VI patients may be falsely high due to clouded corneas and increased corneal rigidity. The swept-source optical coherence tomography helps ophthalmologist to investigate the angle structure and the pathophysiology of glaucoma caused by MPS.

2.
Materials (Basel) ; 12(22)2019 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-31752215

RESUMO

Precision glass molding is a revolutionary technology for achieving high precision and efficient manufacturing of glass aspheric lenses. The material properties of glass, including elastic modulus and viscosity, are highly dependent on temperature fluctuations. This paper aims to investigate the effect of elastic modulus on the high-temperature viscoelasticity of glass and the accuracy of the finite element simulation of the molding process for glass aspheric lenses. The high-temperature elastic modulus of D-ZK3L glass is experimentally measured and combined with the glass cylinder compression creep curve to calculate the high temperature viscoelasticity of D-ZK3L. Three groups of viscoelastic parameters are obtained. Based on this, the molding process of the molded aspheric lens is simulated by the nonlinear finite element method (FEM). The surface curves of lenses obtained by simulation and theoretical analyses are consistent. The simulation results obtained at different initial elastic modulus values indicate that the elastic modulus has a great influence on the precision of the FEM-based molding process of glass aspheric lenses.

3.
World J Clin Cases ; 7(20): 3289-3295, 2019 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-31667181

RESUMO

BACKGROUND: We describe the treatment strategy for a patient who was found to have a partial hydatidiform mole and coexisting fetus (PHMCF) during the second trimester. The patient was a 38-year-old Chinese woman who had become pregnant following in vitro fertilization and embryo transplantation. We wanted to determine the safest therapeutic strategy to terminate the PHMCF during the second trimester. CASE SUMMARY: In this case, we present a patient who was found to have a PHMCF complicated with serious continuous vaginal bleeding and pre-eclampsia during the second trimester. After careful evaluation, the pregnancy was considered to be unsustainable and was terminated via caesarean section (CS). An infant with weak vital signs and a partially cystic placenta measuring 110 mm × 95 mm × 35 mm were delivered by CS. The patient was discharged after 4 d. The serum levels of ß-human chorionic gonadotropin decreased to within a normal range 5 wk after the operation, and no evidence of persistent trophoblastic disease or lung metastases was noticed at the 6-mo follow-up. CONCLUSION: CS termination of PHMCF during the second trimester may be a relatively safe therapeutic strategy.

4.
Dalton Trans ; 48(48): 17858-17863, 2019 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-31777910

RESUMO

Efficient removal of radioactive 90Sr from nuclear waste solutions and natural water systems is of vital importance due to its radioactive nature and high mobility. We present here an anionic layered compound (NC4H12)(NC2H8)2[In3(pydc)6]·13.1H2O (SZ-6; pydc = 2,5-pyridinedicarboxylic acid) with the potential remediation ability towards radioactive Sr2+ from seawater. This material exhibits excellent ß and γ radiation resistance both in air and in aqueous solutions. Besides, this material could maintain its structural integrity in real seawater for 77 days. The adsorption experiment results show that SZ-6 exhibits superior Sr2+ removal capability over a wide pH range from 4 to 12 with fast adsorption kinetics and high selectivity. The effective removal of 90Sr from real seawater was demonstrated as well. Our results strongly suggest the potential application of SZ-6 for selectively capturing radionuclides in natural water systems.

5.
Sci Transl Med ; 11(510)2019 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-31534017

RESUMO

Transforming growth factor-ß1 (TGFß1) has been identified as a major pathogenic factor underlying the development of diabetic nephropathy (DN). However, the current strategy of antagonizing TGFß1 has failed to demonstrate favorable outcomes in clinical trials. To identify a different therapeutic approach, we designed a mass spectrometry-based DNA-protein interaction screen to find transcriptional repressors that bind to the TGFB1 promoter and identified Yin Yang 1 (YY1) as a potent repressor of TGFB1. YY1 bound directly to TGFB1 promoter regions and repressed TGFB1 transcription in human renal mesangial cells. In mouse models, YY1 was elevated in mesangial cells during early diabetic renal lesions and decreased in later stages, and knockdown of renal YY1 aggravated, whereas overexpression of YY1 attenuated glomerulosclerosis. In addition, although their duration of diabetic course was comparable, patients with higher YY1 expression developed diabetic nephropathy more slowly compared to those who presented with lower YY1 expression. We found that a small molecule, eudesmin, suppressed TGFß1 and other profibrotic factors by increasing YY1 expression in human renal mesangial cells and attenuated diabetic renal lesions in DN mouse models by increasing YY1 expression. These results suggest that YY1 is a potent transcriptional repressor of TGFB1 during the development of DN in diabetic mice and that small molecules targeting YY1 may serve as promising therapies for treating DN.

6.
Exp Mol Med ; 51(8): 96, 2019 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-31409770

RESUMO

Traumatic optic neuropathy is an injury to the optic nerve that leads to vision loss. Autophagy is vital for cell survival and cell death in central nervous system injury, but the role of autophagy in traumatic optic nerve injury remains uncertain. Optic nerve crush is a robust model of traumatic optic nerve injury. p62 siRNA and rapamycin are autophagy inducers and have different neuroprotective effects in the central nervous system. In this study, p62 and rapamycin induced autophagy, but only p62 siRNA treatment provided a favorable protective effect in visual function and retinal ganglion cell (RGC) survival. Moreover, the number of macrophages at the optic nerve lesion site was lower in the p62-siRNA-treated group than in the other groups. p62 siRNA induced more M2 macrophage polarization than rapamycin did. Rapamycin inhibited both mTORC1 and mTORC2 activation, whereas p62 siRNA inhibited only mTORC1 activation and maintained mTORC2 and Akt activation. Inhibition of mTORC2-induced Akt activation resulted in blood-optic nerve barrier disruption. Combined treatment with rapamycin and the mTORC2 activator SC79 improved RGC survival. Overall, our findings suggest that mTORC2 activation after autophagy induction is necessary for the neuroprotection of RGCs in traumatic optic nerve injury and may lead to new clinical applications.

7.
Diabet Med ; 36(12): 1671-1678, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31392737

RESUMO

AIM: To evaluate the value and feasibility of capillary glucose assessment, combined with other non-laboratory measures, in screening for diabetes and prediabetes in the community. METHODS: In this cross-sectional study, we assessed fasting capillary glucose, fasting plasma glucose, and both capillary glucose and plasma glucose values after 2-h oral glucose tolerance tests in a total of 3736 samples. We determined the optimal threshold of capillary glucose using receiver-operating characteristic curve analysis. The effect of screening methods using capillary glucose combined with other variables, such as age, BMI and waist circumference, was assessed according to area under the receiver-operating characteristic curve. RESULTS: There was a strong positive correlation between capillary glucose and venous plasma glucose. The area under the curve for the model using fasting capillary glucose to screen for impaired fasting glucose was 0.722, while that for the model using capillary glucose after a 2-h oral glucose tolerance test to screen for impaired glucose tolerance was 0.916. The area under the curve for the model using fasting capillary glucose to screen for diabetes was 0.835, while that for the model using 2-h oral glucose tolerance test capillary glucose was 0.912. The area under the curve for the model using fasting capillary glucose + 2-h oral glucose tolerance test capillary glucose to screen for diabetes was 0.945. The discriminatory capability of models using capillary glucose was somewhat improved by adding non-laboratory variables. CONCLUSIONS: Capillary glucose could be an alternative for screening for diabetes and prediabetes, especially in low-resource areas.

8.
Antioxidants (Basel) ; 8(6)2019 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-31146432

RESUMO

An ultrasonic-assisted extraction (UAE) method was adopted to extract natural antioxidants from edible Gordonia axillaris fruit. Single-factor experiments and response surface methodology were conducted to investigate the influences of five different parameters on antioxidant capacity. The optimal conditions of the UAE were 39.78% ethanol, 30.94 mL/g solvent/material ratio, 59.47 min extraction time, 40 °C temperature, and 400 W ultrasonication power. The antioxidant capacity was 525.05 ± 14.34 µmol Trolox/g DW under the optimal conditions, which was in agreement with the predicted one (531.71 µmol Trolox/g DW). Additionally, in comparison with two traditional methods (maceration and Soxhlet extraction), the established UAE method greatly improved the yield of antioxidants and significantly reduced the extraction time. Besides, nine phenolic compounds were identified and quantified in the extract of Gordonia axillaris fruits by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), including rutin, gallic acid, protocatechuic acid, epicatechin, 2-hydrocinnamic acid, p-coumaric acid, quercetin, epicatechin gallate, and ferulic acid. The richness of phenolic compounds in the Gordonia axillaris fruits indicated its potential health benefits, and its extract rich in antioxidants could be developed into functional food or nutraceuticals with the potential to prevent certain diseases induced by oxidative stress, such as cardiovascular diseases and cancers. This study also provided a way to enhance the economic values of Gordonia axillaris fruits compared to raw fruits.

9.
ACS Appl Mater Interfaces ; 11(24): 21619-21626, 2019 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-31140771

RESUMO

The nano-MOF+ technique was employed by assembling nanoporous metal-organic framework (MOF) UiO-66 with nanoscale zero-valent iron (ZVI) particles to remove uranyl ions from aqueous solution under anoxic condition for the first time. The synthesized composite of Fe0@UiO-66-COOH exhibits a synergic effect between uranyl sorption by MOF host of UiO-66-COOH and chemical reduction by ZVI, reaching much elevated removal capacity and rate in comparison to those of the pristine UiO-66-COOH. The combined complexation and reduction mechanisms are further elucidated by the synchrotron radiation X-ray absorption near-edge structure analysis. This work highlights the bright future of the nano-MOF+ technique in the application of uranium removal, especially for the remediation of the uranium-contaminated subsurface environment.

10.
J Glaucoma ; 28(8): e145-e146, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31135589
11.
J Agric Food Chem ; 67(13): 3595-3604, 2019 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-30865451

RESUMO

Anthocyanidin synthase from Vitis vinifera ( VvANS) catalyzes the in vitro transformation of the natural isomer of leucocyanidin, 2 R,3 S,4 S- cis-leucocyanidin, into 2 R,4 S-flavan-3,3,4-triol ([M + H]+, m/ z 323) and quercetin. The C3-hydroxylation product 2 R,4 S-flavan-3,3,4-triol is first produced and its C3,C4-dehydration product is in tautomeric equilibrium with (+)-dihydroquercetin. The latter undergoes a second VvANS-catalyzed C3-hydroxylation leading to a 4-keto-2 R-flavan-3,3-gem-diol which upon dehydration gives quercetin. The unnatural isomer of leucocyanidin, 2 R,3 S,4 R- trans-leucocyanidin, is similarly transformed into quercetin upon C3,C4-dehydration, but unlike 3,4- cis-leucocyanidin, it also undergoes some C2,C3-dehydration followed by an acid-catalyzed hydroxyl group extrusion at C4 to give traces of cyanidin. Overall, the C3,C4- trans isomer of leucocyanidin is transformed into 2 R,4 R-flavan-3,3,4-triol (M + 1, m/ z 323), (+)-DHQ, (-)-epiDHQ, quercetin, and traces of cyanidin. Our data bring the first direct observation of 3,4- cis-leucocyanidin- and 3,4- trans-leucocyanidin-derived 3,3-gem-diols, supporting the idea that the generic function of ANS is to catalyze the C3-hydroxylation of its substrates. No cyanidin is produced with the natural cis isomer of leucocyanidin, and only traces with the unnatural trans isomer, which suggests that anthocyanidin synthase requires other substrate(s) for the in vivo formation of anthocyanidins.


Assuntos
Flavonoides/química , Oxigenases/química , Proteínas de Plantas/química , Quercetina/química , Vitis/enzimologia , Biocatálise , Biotransformação , Isomerismo , Espectrometria de Massas , Oxirredução
12.
Artigo em Inglês | MEDLINE | ID: mdl-30621567

RESUMO

Backgroud: The present study aimed to investigate the association between immune cells and gestational diabetes mellitus (GDM) and identify a reasonable predictor of insulin resistance in women with GDM. OBJECTIVE: The clinical and biochemical characteristics of 124 women with GDM and 168 healthy pregnant women were compared. METHODS: The percentage of immune cells in the blood of the subjects was analyzed by flow cytometry. Pearson's correlation analysis revealed the correlation between the percentage of B lymphocytes and insulin resistance. A cutoff point was determined for the percentage of B lymphocytes, based on insulin resistance, using receiver operating characteristic (ROC) curves. RESULTS: Compared to the healthy pregnant women, the percentages of B lymphocytes and IgA produced by B-cells were significantly different in women with GDM. The percentage of B lymphocytes was positively related to insulin resistance.The number of 14.05% of B lymphocytes was an optimal cutoff point that predicted the insulin resistance in women with GDM. CONCLUSION: The percentage of B lymphocytes was positively associated with insulin resistance, and hence, might serve as an appropriate predictor of insulin resistance in women with GDM.


Assuntos
Linfócitos B/imunologia , Diabetes Gestacional/sangue , Diabetes Gestacional/imunologia , Resistência à Insulina/fisiologia , Adulto , Linfócitos B/metabolismo , Diabetes Gestacional/diagnóstico , Feminino , Humanos , Valor Preditivo dos Testes , Gravidez
13.
Gynecol Endocrinol ; 35(2): 174-178, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30182781

RESUMO

Gestational diabetes mellitus (GDM) imparts a high risk of developing postpartum diabetes and is considered to be an early stage of type 2 diabetes mellitus (T2DM). In this study, a 75-g oral glucose tolerance test was performed on 472 women with GDM at 6-8 weeks after delivery. The clinical and metabolic characteristics were compared between the patients with normal glucose tolerance (NGT) and abnormal glucose metabolism (AGM). These data were then compared between pre-diabetic and diabetic patients. A total of 37.7% of the women with GDM continued to have abnormal glucose levels after delivery. Compared with the women who reverted to normal, HOMA-IR was significantly higher in AGM. A multiple stepwise regression analysis revealed that age, the postpartum body mass index (BMI), low density lipoprotein-cholesterol (LDL-C), 2 h glucose load plasma glucose (2 h PG), triglycerides (TG), hemoglobin A1c (HbA1c), 1 h glucose load plasma insulin (INS) level, and 2 h INS level were independent risk factors for the development of insulin resistance after delivery. This study has identified a high prevalence of AGM after GDM. Insulin resistance appears to be the major contributor. Any treatment to reduce the postpartum BMI and lipids level may be beneficial to decrease insulin resistance.


Assuntos
Diabetes Mellitus Tipo 2/metabolismo , Diabetes Gestacional/metabolismo , Intolerância à Glucose/metabolismo , Células Secretoras de Insulina/metabolismo , Período Pós-Parto/metabolismo , Estado Pré-Diabético/metabolismo , Adulto , Grupo com Ancestrais do Continente Asiático , Glicemia/metabolismo , Índice de Massa Corporal , China/epidemiologia , LDL-Colesterol/metabolismo , Diabetes Mellitus Tipo 2/epidemiologia , Diabetes Gestacional/epidemiologia , Feminino , Intolerância à Glucose/epidemiologia , Hemoglobina A Glicada/metabolismo , Humanos , Insulina/metabolismo , Resistência à Insulina , Estado Pré-Diabético/epidemiologia , Gravidez , Análise de Regressão , Fatores de Risco , Triglicerídeos/metabolismo
14.
Chempluschem ; 84(7): 913-918, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31943983

RESUMO

1,3-oxazinane is an ideal framework for advanced energetic materials because of its compact skeleton and the presence of several modifiable sites. However, investigations on characterization and performance of 1,3-oxazinane energetic compounds are extremely limited. Two heterocyclic 1,3-oxazinane molecules were synthesized under different Mannich condensation processes and further reacted to form nitro- and azide-substituted energetic compounds 3,5,5-trinitro-1,3-oxazinane (TNTON) and 5-azido-3,5-dinitro-1,3-oxazinane (ADTON), in good yields. Interestingly, the two energetic molecules showed distinct physical properties. ADTON shows an impressive glass transition temperature (Tg) as low as -46 °C with high density, which is highly suitable for rate-accelerating materials. TNTON exhibits good thermal stabilities (melting point of 89 °C and a decomposition point of 231 °C) and highly insensitive behavior (38 J, 360 N). The theoretical detonation pressure of TNTON is ca. 63 % higher than that of TNT, indicating broad application prospects in melt-cast explosives.

15.
Mol Ther Nucleic Acids ; 13: 55-63, 2018 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-30236833

RESUMO

Circular RNAs (circRNAs) are a class of noncoding RNAs that regulate gene expression at the posttranscriptional level. The specific functions of circRNAs in ovarian cancer are yet to be established. Previous sequencing analyses have revealed an abnormal expression of hsa_circ_0061140 in ovarian cancer. The main aim of the present study is to establish the specific role of hsa_circ_0061140 in ovarian cancer. circRNA expression in ovarian cancer cells was detected via real-time qPCR. The effects on specific cellular characteristics (proliferation, migration, and the EMT) and subcellular localization of hsa_circ_0061140 were assessed via RNA fluorescence in situ hybridization, knockdown, and luciferase reporter assays in the SKOV3 and A2780 cell lines. Tumorigenesis was induced in nude mice to assess the effects of hsa_circ_0061140 on ovarian cancer growth in vivo. Our results showed that hsa_circ_0061140 was upregulated in ovarian cancer cell lines. Knockdown of hsa_circ_0061140 suppressed cell proliferation and migration, both in vivo and in vitro, by inhibiting FOXM1 expression through sponging miR-370. Overexpression of FOXM1 or suppression of miR-370 rescued hsa_circ_0061140 silencing-induced inhibition of cell proliferation, migration, and the EMT. The associations among hsa_circ_0061140, miR-370, and FOXM1 were confirmed via bioinformatic prediction and fluorescein reporter experiments. Thus, hsa_circ_0061140 appeared to function as a competing endogenous RNA of miR-370 that promoted cell growth and metastasis in ovarian cancer through regulation of the miR-370/FOXM1 pathway mediating EMT.

16.
Gigascience ; 7(6)2018 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-29917066

RESUMO

Background: Resting-state functional magnetic resonance imaging (RS-fMRI) has frequently been used to investigate local spontaneous brain activity in Parkinson's disease (PD) in a whole-brain, voxel-wise manner. To quantitatively integrate these studies, we conducted a coordinate-based (CB) meta-analysis using the signed differential mapping method on 15 studies that used amplitude of low-frequency fluctuation (ALFF) and 11 studies that used regional homogeneity (ReHo). All ALFF and ReHo studies compared PD patients with healthy controls. We also performed a validation RS-fMRI study of ALFF and ReHo in a frequency-dependent manner for a novel dataset consisting of 49 PD and 49 healthy controls. Findings: Decreased ALFF was found in the left putamen in PD by meta-analysis. This finding was replicated in our independent validation dataset in the 0.027-0.073 Hz band but not in the conventional frequency band of 0.01-0.08 Hz. Conclusions: Findings from the current study suggested that decreased ALFF in the putamen of PD patients is the most consistent finding. RS-fMRI is a promising technique for the precise localization of abnormal spontaneous activity in PD. However, more frequency-dependent studies using the same analytical methods are needed to replicate these results. Trial registration: NCT NCT03439163. Registered 20 February 2018, retrospectively registered.


Assuntos
Imagem por Ressonância Magnética , Doença de Parkinson/fisiopatologia , Putamen/fisiopatologia , Descanso/fisiologia , Idoso , Estudos de Casos e Controles , Demografia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Doença de Parkinson/diagnóstico por imagem , Putamen/diagnóstico por imagem , Reprodutibilidade dos Testes
17.
Mol Biol Rep ; 45(4): 511-522, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29740785

RESUMO

Myostatin is a negative regulator of skeletal muscle growth. Muscle tissue is the largest tissue in the body and influences body growth. Commercial Avian broiler chickens are selected for high growth rate and muscularity. Daweishan mini chickens are a slow growing small-sized chicken breed. We investigated the relations between muscle (breast and leg) myostatin mRNA expression and body and muscle growth. Twenty chickens per breed were slaughtered at 0, 30, 60, 90, 120, and 150 days of age. Body and muscle weights were higher at all times in Avian chickens. Breast muscle myostatin expression was higher in Avian chickens than in Daweishan mini chickens at day 30. Myostatin expression peaked at day 60 in Daweishan mini chickens and expression remained higher in breast muscle. Daweishan mini chickens myostatin expression correlated positively with carcass weight, breast and leg muscle weight from day 0 to 60, and correlated negatively with body weight from day 90 to 150, while myostatin expression in Avian chickens was negatively correlated with carcass and muscle weight from day 90 to 150. The results suggest that myostatin expression is related to regulation of body growth and muscle development, with two different regulatory mechanisms that switch between days 30 and 60.


Assuntos
Galinhas/genética , Desenvolvimento Muscular/genética , Miostatina/genética , Criação de Animais Domésticos/métodos , Animais , Proteínas Aviárias/genética , Cruzamento , Galinhas/metabolismo , Expressão Gênica/genética , Regulação da Expressão Gênica/genética , Músculo Esquelético/crescimento & desenvolvimento , Miostatina/metabolismo , Fenótipo , RNA Mensageiro/análise
18.
J Pineal Res ; 65(2): e12500, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29702752

RESUMO

Melatonin has been detected in plants in 1995; however, the function and signaling pathway of this putative phytohormone are largely undetermined due to a lack of knowledge about its receptor. Here, we discovered the first phytomelatonin receptor (CAND2/PMTR1) in Arabidopsis thaliana and found that melatonin governs the receptor-dependent stomatal closure. The application of melatonin induced stomatal closure through the heterotrimeric G protein α subunit-regulated H2 O2 and Ca2+ signals. The Arabidopsis mutant lines lacking AtCand2 that encodes a candidate G protein-coupled receptor were insensitive to melatonin-induced stomatal closure. Accordingly, the melatonin-induced H2 O2 production and Ca2+ influx were completely abolished in cand2. CAND2 is a membrane protein that interacts with GPA1 and the expression of AtCand2 was tightly regulated by melatonin in various organs and guard cells. CAND2 showed saturable and specific 125 I-melatonin binding, with apparent Kd (dissociation constant) of 0.73 ± 0.10 nmol/L (r2  = .99), demonstrating this protein is a phytomelatonin receptor (PMTR1). Our results suggest that the phytomelatonin regulation of stomatal closure is dependent on its receptor CAND2/PMTR1-mediated H2 O2 and Ca2+ signaling transduction cascade.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Sinalização do Cálcio/fisiologia , Melatonina/metabolismo , Estômatos de Plantas/metabolismo , Receptores Acoplados a Proteínas-G/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Subunidades alfa de Proteínas de Ligação ao GTP/genética , Subunidades alfa de Proteínas de Ligação ao GTP/metabolismo , Estômatos de Plantas/genética , Receptores Acoplados a Proteínas-G/genética
19.
Dalton Trans ; 47(15): 5161-5165, 2018 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-29561013

RESUMO

A new 1-D zirconium phosphonate [(CH3)2NH2]2[Zr(CH2(HPO3)(PO3))2] (SZ-5) was synthesized via a solvothermal reaction and its single crystal structure was elucidated. SZ-5 exhibits efficient strontium exchange capability with high uptake capacity and selectivity, as further demonstrated by the radioactive Sr-90 removal from a real contaminated seawater sample with an extremely high ionic strength. In addition, the measured proton conductivity at 90 °C and 90% relative humidity (RH) is 5.65 × 10-4 S cm-1. The efficient ion-exchange ability and the moderate proton conductivity suggest the potential applications of SZ-5 in fuel cells or in the remediation of contaminated water.

20.
J Agric Food Chem ; 66(1): 351-358, 2018 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-29231723

RESUMO

(+)-2,3-trans-3,4-cis-Leucocyanidin was produced by acidic epimerization of (+)-2,3-trans-3,4-trans-leucocyanidin synthesized by reduction of (+)-dihydroquercetin with NaBH4, and structures of the two stereoisomers purified by C18- and phenyl-reverse-phase high-performance liquid chromatography (HPLC) were confirmed by NMR spectroscopy. We confirm that only 3,4-cis-leucocyanidin is used by leucoanthocyanidin reductase as substrate. The two stereoisomers are quite stable in aqueous solution at -20 °C. Characterization of the two stereoisomers was also performed using electrospray ionization tandem mass spectrometry (ESI-MS/MS), and we discuss here for the first time the corresponding MS/MS fragmentation pathways, which are clearly distinct. The main difference is that of the mode of dehydration of the 3,4-diol in positive ionization mode, which involves a loss of hydroxyl group at either C3 or C4 for the 3,4-cis isomer but only at C3 for the 3,4-trans isomer. Tandem mass spectrometry therefore proves useful as a complementary methodology to NMR to identify each of the two stereoisomers.


Assuntos
Flavonoides/química , Espectrometria de Massas em Tandem/métodos , Estrutura Molecular , Estereoisomerismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA