Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 158
Filtrar
1.
J Org Chem ; 86(19): 13491-13502, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34514788

RESUMO

In this study we found that 2,6-dimethanolpyridine displays good complementarity toward di(ethylene glycol) for the complexation of Na+ ions, allowing us to use this recognition system for the efficient synthesis of hetero[2]catenanes; indeed, it allowed us to attach multiple copies of [2]catenanes to branched systems presenting multiple isophthalaldehyde units. When we attempted to form a catenane from a preformed macrocycle featuring only a single di(ethylene glycol) unit, reacting it with a di(ethylene glycol) derivative presenting two amino termini, isophthalaldehyde, and templating Na+ ions [i.e., with the aim of using di(ethylene glycol)·Na+·di(ethylene glycol) recognition to template the formation of the interlocked imino macrocycle], the yields of the hetero[2]catenane and homo[2]catenane, comprising two imino macrocyclic units, were both poor (14% and 7%, respectively). In contrast, when one or two 2,6-dimethanolpyridine units were present in the preformed macrocycles, their reactions with the same diamine, dialdehyde, and Na+ ions provided the hetero[2]catenanes with high selectivity and efficiency (44% and 64% yields, respectively), with minimal formation of the competing homo[2]catenane. The high complementary of the 2,6-dimethanolpyridine·Na+·di(ethylene glycol) ligand pair allowed us to synthesize [2]catenane dimers and trimers directly from corresponding isophthalaldehyde-presenting cores, with yields, after subsequent reduction and methylation, of 42% and 31%, respectively.

2.
Org Lett ; 23(15): 5787-5792, 2021 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-34240877

RESUMO

We report a new slippage system based on p-tert-butylbenzyl-terminated imidazolium ions and di(ethylene glycol)-containing macrocycles and their use as linking units for the construction of a prototypical molecular "Lock & Lock" box from a resorcinarene-based cavitand "bowl" and a porphyrin "cover". The multivalent structure with four slippage linkers provided the molecular box with high stability, yet the system dissociated into its two components upon application of suitable external stimuli.

3.
Food Chem ; 354: 129590, 2021 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-33756333

RESUMO

Honey is widely consumed by humans, due to its multiple applications as a food constituent and its therapeutic effects. This study reports on the discrimination of honey products from different geographical and botanical sources, as well as honey products containing distinct forms of syrup used in honey adulteration. Sequential window acquisition of all theoretical fragment ion spectra mass spectrometry (SWATH-MS)-based proteomic analysis combined with chemometrics was successfully applied in identifying characteristic proteins that can be used as biomarkers of the original source of honey. Honey samples from different producing regions (Tainan, Changhua, and Taichung), countries (Taiwan and Thailand), and distinct botanical sources (longan and litchi) were clearly distinguished by the developed orthogonal projections to latent structures discriminant analysis (OPLS-DA) model with good fitness and prediction ability. Furthermore, we successfully discriminated the adulteration of honey with syrup in different proportions (even with honey content as low as 20%) with this proteomic SWATH-MS platform.


Assuntos
Análise de Alimentos/métodos , Qualidade dos Alimentos , Mel/análise , Espectrometria de Massas , Néctar de Plantas/análise , Proteômica , Análise Discriminante , Contaminação de Alimentos/análise , Humanos
4.
Oncogenesis ; 9(12): 104, 2020 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-33281189

RESUMO

Human HLTF participates in the lesion-bypass mechanism through the fork reversal structure, known as template switching of post-replication repair. However, the mechanism by which HLTF promotes the replication progression and fork stability of damaged forks remains unclear. Here, we identify a novel protein-protein interaction between HLTF and PARP1. The depletion of HLTF and PARP1 increases chromosome breaks, further reduces the length of replication tracks, and concomitantly increases the number of stalled forks after methyl methanesulfonate treatment according to a DNA fiber analysis. The progression of replication also depends on BARD1 in the presence of MMS treatment. By combining 5-ethynyl-2'-deoxyuridine with a proximity ligation assay, we revealed that the HLTF, PARP1, and BRCA1/BARD1/RAD51 proteins were initially recruited to damaged forks. However, prolonged stalling of damaged forks results in fork collapse. HLTF and PCNA dissociate from the collapsed forks, with increased accumulation of PARP1 and BRCA1/BARD1/RAD51 at the collapsed forks. Our results reveal that HLTF together with PARP1 and BARD1 participates in the stabilization of damaged forks, and the PARP1-BARD1 interaction is further involved in the repair of collapse forks.

5.
Artigo em Inglês | MEDLINE | ID: mdl-33341362

RESUMO

BACKGROUND: The global rise in nosocomial infections associated with gram-negative bacteria and the spread of multi-drug resistant Acinetobacter baumannii (MDR-AB) pose public health concerns. This study investigates the inhibitory effects and possible inhibitory mechanism of Pseudomonas aeruginosa (PA) on selected clinical strains of A. baumannii (AB) isolated from Taiwanese patients. METHODS: Four and eight clinical strains of AB and PA, respectively, were randomly selected from the bacterial collection of Feng-Yuan Hospital, Taiwan. Antimicrobial-susceptibility was performed on the AB strains. Inhibition potential of the PA strains against AB was assessed by measuring the inhibition zones. In vitro analysis using phenazine-1-carboxamide (PCN) was conducted to assess the possible inhibitory mechanism of PA, which was later confirmed in the clinical isolates by liquid chromatography-mass spectrometry. RESULTS: All the clinical AB strains showed resistance to the eleven antibiotics and were classified as MDR-AB. The nine PA strains exert either a high (PA3596, PA3681, PA3772, and ATCC27853) or a low (PA3613, PA3625, PA3712, PA3715, and PA3744) degree of inhibition against AB strains. 0.25 mg/ml PCN had a clearer inhibition zone than 0.05 mg/ml PCN, suggesting a dose-dependent inhibition of PCN on the AB strains. The four PA strains that demonstrated a high degree of inhibition had a relatively high amount of PCN. CONCLUSION: Selected strains of PA exert inhibitory actions on MDR-AB with PCN being a possible inhibitory agent. This finding raises the possibility of developing effective therapeutic antibiotics and disinfectant from specific components of PA for the treatment and control of Acinetobacter-associated infections in hospital settings.

6.
Sci Rep ; 10(1): 6597, 2020 08 05.
Artigo em Inglês | MEDLINE | ID: mdl-32759951

RESUMO

Cnaphalocrocis medinalis is a major insect pest of rice in Asia. A few defensive enzymes were reported to show higher activities in a resistant rice line (Qingliu) than in a susceptible rice line (TN1) upon leaffolder infestation. However, the overall molecular regulation of the rice defense response against leaffolder herbivory is unknown. Here, differential proteomic analysis by SWATH-MS was performed to identify differentially expressed proteins between the two rice varieties, Qingliu and TN1, at four time points of leaffolder herbivory, 0, 6, 24, and 72 h. Gene Ontology (GO) enrichment of the differentially expressed proteins indicated overrepresentation of (1) photosynthesis, (2) amino acid and derivative metabolic process, and (3) secondary metabolic process. Phenylalanine ammonia lyase and chalcone synthase, which catalyze flavonoid biosynthesis, and lipoxygenase, which catalyzes jasmonic acid biosynthesis, exhibited higher expression in Qingliu than in TN1 even before insect herbivory. Momentary activation of the light reaction and Calvin cycle was detected in Qingliu at 6 h and 24 h of insect herbivory, respectively. At 72 h of insect herbivory, amino acid biosynthesis and glutathione-mediated antioxidation were activated in Qingliu. A defense response involving jasmonic acid signaling, carbon remobilization, and the production of flavonoids and glutathione could underlie the resistance of Qingliu to leaffolder.


Assuntos
Resistência à Doença/genética , Lepidópteros/patogenicidade , Oryza/genética , Proteoma/genética , Aciltransferases/genética , Aciltransferases/metabolismo , Animais , Lipoxigenase/genética , Lipoxigenase/metabolismo , Oryza/parasitologia , Fenilalanina Amônia-Liase/genética , Fenilalanina Amônia-Liase/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Proteoma/metabolismo
7.
Rapid Commun Mass Spectrom ; 34(15): e8825, 2020 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-32396680

RESUMO

RATIONALE: Oriental Beauty, a type of oolong tea native to Taiwan, is highly prized by connoisseurs for its unique fruity aroma and sweet taste. Leaves of Oriental Beauty vary in appearance, aroma, and taste, depending on the degree of tea green leafhopper (Jacobiasca formosana) infestation. In this study, the aim is to investigate the differential expression of proteins in leaves with low, medium, and high degrees of leafhopper infestation. METHODS: Proteomic techniques 2DE (two-dimensional electrophoresis) and nanoscale liquid chromatography/tandem mass spectrometry (LC/MS/MS) were used to investigate the differential expression of proteins in tea leaves with different degrees of leafhopper infestation. RESULTS: A total of 89 proteins were found to exhibit significant differences in expression. In a gene ontology analysis, most of these proteins participated in biosynthesis, carbohydrate metabolism, transport, responses to stress, and amino acid metabolism. CONCLUSIONS: These results indicated that the unique aroma and taste of the leaves might be influenced by their protein expression profiles, as well as related factors such as defensive responses to tea green leafhopper saliva.


Assuntos
Camellia sinensis/parasitologia , Hemípteros/fisiologia , Folhas de Planta/química , Animais , Camellia sinensis/química , Camellia sinensis/genética , Camellia sinensis/metabolismo , Cromatografia Líquida , Comportamento Alimentar , Aromatizantes/química , Aromatizantes/metabolismo , Odorantes/análise , Folhas de Planta/genética , Folhas de Planta/metabolismo , Folhas de Planta/parasitologia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Proteômica , Taiwan , Espectrometria de Massas em Tandem
8.
Chem Commun (Camb) ; 56(35): 4773-4776, 2020 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-32232269

RESUMO

In this study imidazolium and imidazolinium centers in precursor [2]rotaxanes were deprotonated to obtain interlocked molecules featuring stabilized N-heterocyclic carbene centers. The encircling macrocyclic components enhanced the persistence of the otherwise unstable imidazolidin-2-ylidenes in solution at 253 K for more than a week in the absence of air.

9.
Anal Bioanal Chem ; 412(17): 4057-4065, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32248396

RESUMO

Graphene oxide (GO) has the ability to absorb certain compounds, and it can be modified with functional groups for different purposes; for instance, iron oxide (IO) nanoparticles can be used to concentrate analyte by a magnet. Recently, many kinds of GO have been developed, such as single-layer GO (SLGO), two-to-four layers of GO (i.e., few-layer GO, FLGO2-4), and four-to-eight layers of GO (i.e., multi-layer GO, MLGO4-8). However, the abilities of these layered GO coated with IO nanoparticles have not been investigated. In this study, we conducted a novel analysis of glimepiride by using layered GO-coated magnetic clusters of IO nanoparticles that were synthesized through a simple and facile emulsion-solvent evaporation method. The methodology is based on (i) enrichment of glimepiride using the layered GO-coated magnetic clusters of IO nanoparticles (IO@SLGO, IO@FLGO2-4, and IO@MLGO4-8), and (ii) rapid determination using magnetic cluster-based surface-assisted laser desorption/ionization time-of-flight mass spectrometry (SALDI-TOFMS). We found that IO@MLGO4-8, the magnetic cluster with the greatest number of GO layers, had the best limit of detection (28.6 pmol/µL for glimepiride). The number of GO layers played a significant role in increasing the sensitivity of the SALDI-MS, indicating that the size of GO in the magnetic clusters contributed to the desorption/ionization efficiency. To the best of our knowledge, this is the first study to enrich glimepiride using magnetic clusters of different GO types and to show that the glimepiride in HLB purified urine adsorbed by magnetic clusters can be analyzed by SALDI-TOFMS.


Assuntos
Grafite/química , Hipoglicemiantes/urina , Nanopartículas Magnéticas de Óxido de Ferro/química , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Compostos de Sulfonilureia/urina , Adsorção , Antiarrítmicos/isolamento & purificação , Antiarrítmicos/urina , Humanos , Hipoglicemiantes/isolamento & purificação , Limite de Detecção , Extração Líquido-Líquido/métodos , Nanopartículas Magnéticas de Óxido de Ferro/ultraestrutura , Extração em Fase Sólida/métodos , Compostos de Sulfonilureia/isolamento & purificação
10.
Angew Chem Int Ed Engl ; 59(28): 11278-11282, 2020 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-32249512

RESUMO

We have prepared NHC-CuI complexes with a rotaxane structure and used them as sterically sensitive catalysts for one-pot sequential copper-catalyzed azide/alkyne cycloadditions in solutions containing all of the coupling partners premixed in unprotected form. Most notably, a photolabile and sterically encumbered complex first catalyzed the coupling of a less bulky azide/alkyne pair; after removing the protective macrocyclic component from the rotaxane structure, through irradiation with light, the exposed dumbbell-shaped NHC-CuI complex catalyzed the second click reaction of a bulkier azide/alkyne pair. Using this approach, we obtained predominantly, from a single sealed pot, a bis-triazole product (84 %) from a mixture of two sterically distinct azides and a diyne.

11.
Anal Chim Acta ; 1103: 122-133, 2020 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-32081177

RESUMO

Isoflavones are the major bioactive components in soybeans. Sequential window acquisition of all theoretical fragment ions (SWATH) is a kind of data-independent acquisition (DIA), such that all fragments of each precursor will be preserved in a SWATH-Mass Spectrometry (SWATH-MS) run. In this study, a high-throughput SWATH-MS method for the determination of 12 isoflavones in soybeans was established. Furthermore, amino acids, saponins can be semi-quantitated from the same SWATH-MS data. Combination of targeted quantification and untargeted profiling with SWATH, all bioactive compounds were analyzed within 5 min in 10 min run time, and the method had good linear regression with r2 > 0.99. The precisions (RSD %) of the intra-day and inter-day analyses ranged from 2.11% to 18.7%, and the accuracies (RE%) ranged from -14.39% to 17.48%. The matrix effect ranged from 88.66% to 114.82%. Moreover, 7 varieties of soybeans were analyzed and compared with this robust screening method.


Assuntos
Aminoácidos/análise , Isoflavonas/análise , Saponinas/análise , Soja/química , Cromatografia Líquida de Alta Pressão , Reprodutibilidade dos Testes , Espectrometria de Massas em Tandem/métodos
12.
Rapid Commun Mass Spectrom ; 34 Suppl 1: e8633, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31677360

RESUMO

RATIONALE: Maleic acid is an industrial-grade chemical that is often used in adhesives, stabilizers, and preservatives. It is unknown whether long-term consumption of maleic acid modified starch is harmful to humans. However, many studies have indicated that maleic acid causes renal tubular damage in animal models, even as the associated pathways remain unclear. Sequential window acquisition of all theoretical fragment ion spectra (SWATH) is the most innovative of the label-free quantitative technologies which have better quantification performance. Therefore, SWATH technology was used to investigate the effect of maleic acid on the rat kidney proteome in this study. METHODS: Sprague-Dawley(SD) rats were treated with 0 mg/kg (control), 6 mg/kg (low-dose), 10 mg/kg (medium-dose), and 60 mg/kg (high-dose) of maleic acid. After kidney protein extraction, 28% SDS-PAGE was used, followed by in-gel digestion and desalting. Next, the samples were analyzed with ultra-performance liquid chromatography (UPLC) coupled with quadrupole time-of-flight mass spectrometry (Q-TOF MS), and data-dependent acquisition (DDA) and SWATH technology were also used. The gene ontology and pathway analysis were accomplished. Ultimately, these protein biomarkers were validated by using scheduled high-resolution multiple reaction monitoring (sMRMHR ). RESULTS: Comparisons of the control group with the other three groups revealed that 95, 130, and 103 proteins were expressed at significantly different levels in the control group and in the low-dose, medium-dose, and high-dose groups, respectively. According to the gene ontology analysis, the major processes that these proteins were involved in were metabolic processes, biological regulation, cellular processes, and responses to stimuli; the major functions that these proteins were involved in were binding, hydrolase activity, catalytic activity, and oxidoreductase activity; and the major cellular components hat they were involved in were the cytoplasm, extracellular region, membrane, and mitochondria. According to the KEGG pathway analysis, these proteins were involved in 35 pathways, five of which, the carbohydrate metabolism, folate biosynthesis, renal tubular resorption, amino acid metabolism, and Ras signaling pathways, are discussed in this study. Ultimately, 19 proteins involved in 12 important pathways were validated by sMRMHR . CONCLUSIONS: It was demonstrated that maleic acid caused insufficient energy production, which might lead to a decrease in the activity of the sodium-potassium ATP pump and hydrogen ion ATP pump, which could in turn have caused renal tubular resorption and hydrogen ion regulation to be blocked, thus leading to the accumulation of hydrogen ions in the renal tubules, which would then result in renal tubular acidification followed finally by Fanconi syndrome.


Assuntos
Rim/efeitos dos fármacos , Maleatos/farmacologia , Proteoma/metabolismo , Animais , Rim/química , Rim/metabolismo , Maleatos/efeitos adversos , Espectrometria de Massas/métodos , Proteoma/análise , Proteômica/métodos , Ratos Sprague-Dawley
13.
Sci Rep ; 9(1): 13703, 2019 09 23.
Artigo em Inglês | MEDLINE | ID: mdl-31548578

RESUMO

Cyclin-dependent kinase 5 (Cdk5) is predominantly expressed in neuron and plays an important role in neuronal physiology. Increasing evidence also indicates that Cdk5 may contribute to malignant progression of some types of cancers; however, the underlying mechanism remains elusive. In this study, we found that Cdk5 directly phosphorylated the actin-binding protein adducin-1 (ADD1) at T724 in vitro and in intact cells. The capability of the phosphomimetic T724D mutant to bind to actin filaments was lower than that of wild type ADD1 and the T724A mutant. Cdk5 co-localized with ADD1 at the lamellipodia upon epidermal growth factor (EGF) stimulation. The increased lamellipodia formation and cell migration of human breast cancer cells MDA-MB-231 by EGF were accompanied by Cdk5 activation and increased phosphorylation of ADD1 at T724. Depletion of Cdk5 in MDA-MB-231 cells abrogated the effects of EGF on ADD1 T724 phosphorylation, lamellipodia formation, and cell migration. Likewise, depletion of ADD1 suppressed the effects of EGF on lamellipodia formation, cell migration, and invasion, all of which were restored by FLAG-ADD1 WT and the T724D mutant, but not the T724A mutant. Together, our results suggest that phosphorylation of ADD1 at T724 by Cdk5 is important for EGF-induced cell migration and invasion.


Assuntos
Proteínas de Ligação a Calmodulina/metabolismo , Movimento Celular/fisiologia , Fator de Crescimento Epidérmico/farmacologia , Pseudópodes/efeitos dos fármacos , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Quinase 5 Dependente de Ciclina/metabolismo , Humanos , Fosforilação/efeitos dos fármacos , Pseudópodes/metabolismo
14.
Org Lett ; 21(14): 5708-5712, 2019 07 19.
Artigo em Inglês | MEDLINE | ID: mdl-31283244

RESUMO

The absolute configurations of the two enantiomers of a topologically chiral [2]catenane were determined unambiguously based on HPLC resolution and X-ray crystal analysis. Although structurally dissimilar to simple amino acids, the optical rotations of these separated [2]catenanes share the Clough-Lutz-Jirgensons behavior of amino acids: the optical rotation flips direction in the presence of acid and base, the first example of such behavior for a mechanically interlocked topologically chiral catenane.

15.
Oncogene ; 38(21): 4197-4198, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30814683

RESUMO

The original version of this article contained error in Fig. 6b, where several panels were missing from the published version. The corrected version of this Figure now appears in the article.

16.
Gastroenterology ; 156(6): 1849-1861.e13, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30711629

RESUMO

BACKGROUND & AIMS: Inhibitors of MET have not produced satisfactory outcomes in trials of patients with liver cancer. We investigated the mechanisms of liver tumor resistance to MET inhibitors in mice. METHODS: We tested the effects of MET inhibitors tivantinib and capmatinib in the mouse hepatocellular carcinoma (HCC) cell line HCA-1 and in immune-competent and immunodeficient mice with subcutaneous tumors grown from this cell line. Tumors were collected from mice and tumor cells were analyzed by time-of-flight mass cytometry. We used short hairpin RNAs to weaken expression of MET in Hep3B, SK-HEP-1, HA59T, and HA22T liver cancer cell lines and analyzed cells by immunoblot, immunofluorescence, and immunoprecipitation assays. Mass spectrometry was used to assess interactions between MET and glycogen synthase kinase 3ß (GSK3B), and GSK3B phosphorylation, in liver cancer cell lines. C57/BL6 mice with orthotopic tumors grown from Hep1-6 cells were given combinations of capmatinib or tivantinib and antibodies against programmed cell death 1 (PDCD1; also called PD1); tumors were collected and analyzed by immunofluorescence. We analyzed 268 HCCsamples in a tissue microarray by immunohistochemistry. RESULTS: Exposure of liver cancer cell lines to MET inhibitors increased their expression of PD ligand 1 (PDL1) and inactivated cocultured T cells. MET phosphorylated and activated GSK3B at tyrosine 56, which decreased the expression of PDL1 by liver cancer cells. In orthotopic tumors grown in immune-competent mice, MET inhibitors decreased the antitumor activity of T cells. However, addition of anti-PD1 decreased orthotopic tumor growth and prolonged survival of mice compared with anti-PD1 or MET inhibitors alone. Tissue microarray analysis of HCC samples showed an inverse correlation between levels of MET and PDL1 and a positive correlation between levels of MET and phosphorylated GSK3B. CONCLUSIONS: In studies of liver cancer cell lines and mice with orthotopic tumors, MET mediated phosphorylation and activated GSK3B, leading to decreased expression of PDL1. Combined with a MET inhibitor, anti-PD1 and anti-PDL1 produced additive effect to slow growth of HCCs in mice.


Assuntos
Antígeno B7-H1/metabolismo , Carcinoma Hepatocelular/enzimologia , Glicogênio Sintase Quinase 3 beta/metabolismo , Neoplasias Hepáticas/enzimologia , Proteínas Proto-Oncogênicas c-met/metabolismo , Fator 6 Associado a Receptor de TNF/metabolismo , Evasão Tumoral/efeitos dos fármacos , Animais , Anticorpos Monoclonais/uso terapêutico , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Antígeno B7-H1/antagonistas & inibidores , Antígeno B7-H1/imunologia , Carcinoma Hepatocelular/tratamento farmacológico , Carcinoma Hepatocelular/imunologia , Linhagem Celular Tumoral , Regulação para Baixo , Granzimas/metabolismo , Imidazóis/farmacologia , Imidazóis/uso terapêutico , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Hepáticas/imunologia , Masculino , Camundongos , Fosforilação , Proteínas Proto-Oncogênicas c-met/antagonistas & inibidores , Pirrolidinonas/farmacologia , Pirrolidinonas/uso terapêutico , Quinolinas/farmacologia , Quinolinas/uso terapêutico , Fator 6 Associado a Receptor de TNF/imunologia , Triazinas/farmacologia , Triazinas/uso terapêutico , Ubiquitinação
17.
Oncogene ; 38(21): 4075-4094, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30696956

RESUMO

Vimentin intermediate filaments (VIFs), expressed in most mesenchymal and cancer cells, undergo dramatic reorganization during cell migration; however, the mechanism remains obscure. This study demonstrates that upon growth-factor stimulation, Src directly phosphorylates vimentin at Tyr117, leading to VIF disassembly into squiggles and particles at the cell edge during lamellipodia formation. The protein tyrosine phosphatase SHP2 counteracted the Src effects on VIF tyrosine phosphorylation and organization. VIFs formed by vimentin Y117D mutant were more soluble and dynamic than those formed by the wild-type and Y117F mutant. Increased expression of vimentin promoted growth-factor induced lamellipodia formation and cell migration, whereas the mutants suppressed both. The vimentin-induced increase in lamellipodia formation correlated with the activation of Rac and Vav2, with the latter associated with VIFs and recruited to the plasma membrane upon growth-factor stimulation. These results reveal a novel mechanism for regulating VIF dynamics through Src and SHP2 and demonstrate that proper VIF dynamics are important for Rac activation and cell migration.

18.
Artigo em Inglês | MEDLINE | ID: mdl-30445291

RESUMO

Salvia miltiorrhiza has been widely used in Asia for medicinal purposes for >1000 years due to the high levels of bioactive constituents it contains. In this study, a simple and rapid ultrasound-assisted liquid extraction (5 min) was applied for the extraction of these bioactive constituents. The extracts were analyzed by using rapid ultrahigh performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) with simultaneous positive and negative electrospray ionization in a single analytical run. Eight analytes were separated within 2.2 min during 6 min of run time with UHPLC-MS/MS operated in multiple reaction monitoring (MRM) mode. The concentration of salvianolic acids and tanshinones in the different organs of different varieties of Salvia miltiorrhiza ranged from 6.4 to 382.1 mg/g and 0.03 to 31.7 mg/g, respectively. To the best of our knowledge, this is the first report to characterize the tanshinone compounds found in the flower and stem/leaf of Salvia miltiorrhiza by UHPLC-MS/MS.


Assuntos
Ácidos Cafeicos/análise , Fenantrenos/análise , Componentes Aéreos da Planta/química , Salvia miltiorrhiza/química , Cromatografia Líquida de Alta Pressão/métodos , Limite de Detecção , Modelos Lineares , Extratos Vegetais/análise , Extratos Vegetais/química , Reprodutibilidade dos Testes , Sonicação , Espectrometria de Massas em Tandem/métodos
19.
Psychiatry Res ; 271: 153-160, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30476753

RESUMO

The purposes of this study were to develop the Chinese-version betel quid dependence instrument (BQDI) and to test its reliability and validity. An item pool relevant to betel quid dependence was generated. A panel of three experts assessed content validity including content relevance, clarity, and domain coverage. A cross-sectional study was conducted, consisting of 113 participants from a construction site, betel quid stalls, and a teaching hospital in Taichung, Taiwan. Construct validity was assessed by hypothesizing a significant correlation between the BQDI score and number of pieces-years for betel quid chewing and betel quid biomarkers. The overall Cronbach's alpha coefficient was 0.94. Factor analysis indicated the BQDI consisted of a three-factor structure, including physical and psychological cravings, lack of resistance to betel quid, and maladaptive use. We observed significant associations of BQDI total and factor scores with arecaidine (adjusted odds ratio [OR] for medium total BQDI score: 12.87, 95% CI: 1.45-114.5; high total BQDI score: 28.9, 3.53-236.6) and N-methylnipecotate (medium total BQDI score: 6.18, 1.21-31.62; high total BQDI score: 13.10, 2.72-63.03, respectively). Our results provide preliminary good internal consistency and construct validation of the Chinese-version BQDI as a measure of betel quid dependence in community adults.


Assuntos
Areca , Grupo com Ancestrais do Continente Asiático/psicologia , Transtornos Relacionados ao Uso de Substâncias/diagnóstico , Inquéritos e Questionários/normas , Adulto , Arecolina/análogos & derivados , Estudos Transversais , Análise Fatorial , Feminino , Humanos , Idioma , Masculino , Pessoa de Meia-Idade , Razão de Chances , Reprodutibilidade dos Testes , Taiwan , Traduções
20.
J Pharm Biomed Anal ; 161: 94-100, 2018 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-30145454

RESUMO

The dried root of Danshen (Salvia miltiorrhiza) is a Chinese medicine that has been used in traditional treatments for more than 2000 years in Asia. It has also been used to treat cardiovascular diseases for decades. The goal of this study was to develop a new, fast, and simple ultrahigh-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) analytical method for the analysis of phenolic acids and tanshinones in Danshen. The samples were separated on a Kinetex F5 column (2.1 x 100 mm, 1.7 µm, pentafluorophenyl) using 78% acetonitrile with 0.1% formic acid as the mobile phase with isocratic elution while the flow rate was set at 0.45 mL/min. The analysis was performed in a Waters Xevo TQ mass spectrometer via multiple reaction monitoring (MRM) in polarity switching mode. The linearity values of the calibration curves of eight compounds were in the range from 3 to 3200 ng/mL (r2 > 0.99). Method validation was performed in terms of linearity, the relative standard deviations (RSDs) of the intra-day and inter-day, and it was found that precisions were within 15% and the accuracy ranged from 93% to 118%. The recovery was more than 87%. The limit of detection (LOD) and limit of quantification (LOQ) values of the eight analytes varied between 0.023 to 0.75 ng/mL and 0.375 to 1.5 ng/mL, respectively. This approach has the shortest analysis time for the separation of phenolic acids and tanshinones in Danshen using a UPLC core-shell column with F5 stationary phase. Meanwhile, this robust and high-throughput method not only has a short run time (2 min) but also reduce the consumption of organic solvents.


Assuntos
Abietanos/análise , Cromatografia Líquida de Alta Pressão/métodos , Medicamentos de Ervas Chinesas/química , Hidroxibenzoatos/análise , Salvia miltiorrhiza/química , Espectrometria de Massas em Tandem/métodos , Ensaios de Triagem em Larga Escala/métodos , Limite de Detecção
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...