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1.
Food Microbiol ; 86: 103344, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31703877

RESUMO

This study aimed to evaluate the inhibitory activity of phenyllactic acid (PLA) against the biofilm formation of Enterococcus faecalis and to explore its potential molecular mechanism. The MIC value of PLA that inhibited the growth of E. faecalis R612-Z1 in BHI broth was 5 mg/mL. PLAs at subinhibitory concentrations of 1.25 and 2.50 mg/mL were found to inhibit biofilm formation by a crystal violet staining assay. The cell swimming and swarming motilities of E. faecalis were reduced in the presence of PLA. An apparent decrease in the thickness of PLA-treated biofilms was observed through confocal laser scanning microscopy analysis. The exopolysaccharide production in E. faecalis biofilms was inhibited by EPS quantification assay and scanning electron microscopy (SEM). qRT-PCR analyses showed that PLA down-regulated the transcription of Ebp pili genes (ebpABC) and Epa polysaccharide genes (epaABE). PLA inhibited the biofilm formation by interfering with cell mobility and EPS production of E. faecalis. In addition, PLA at concentrations of 10.0 mg/mL can effectively control the bacterial cells in a three-day-old mature biofilm of E. faecalis grown on 24-well flat-bottom polystyrene plates and stainless-steel surfaces. Thus, PLA is potentially an effective agent to control E. faecalis biofilms.

2.
Int J Cancer ; 2019 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-31633800

RESUMO

Colorectal cancer (CRC) is the third most common cancer and the second leading cause of cancer mortality worldwide. Emerging evidence indicates that tumour cells release substantial amounts of RNA into the bloodstream, in which RNA strongly resists RNases and is present at sufficient levels for quantitative analyses. This study aimed to discover blood-based markers for the early detection of CRC and to ascertain their efficiency in discriminating healthy controls, patients with polyps and adenomas and cancer patients. We first analysed and screened ZFAS1, SNHG11, LINC00909 and LINC00654 in a bioinformatics database and then collected clinical plasma samples for a preliminary small-scale analysis and further large-scale verification. We then explored the mechanism of dominant lncRNA SNHG11 expression in CRC by in vitro and in vivo assays. The combination of ZFAS1, SNHG11, LINC00909 and LINC00654 showed high diagnostic performance for CRC (AUC: 0.937), especially early-stage disease (AUC: 0.935). Plasma levels of the four candidate lncRNAs were significantly reduced in post-operative samples compared to pre-operative samples. A panel including these four lncRNAs performed well in distinguishing patient groups with different stages of colon disease, and SNHG11 exhibited the greatest diagnostic ability to identify precancerous lesions and early-stage tumour formation. Mechanistically, high SNHG11 expression promotes proliferation and metastasis by targeting the Hippo pathway. Taken together, the data indicate that SNHG11 may be a novel therapeutic target for the treatment of CRC and a potential biomarker for the early detection of CRC. This article is protected by copyright. All rights reserved.

3.
Molecules ; 24(20)2019 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-31652500

RESUMO

Saponins in the Camellia sinensis seeds have a broad spectrum of biological properties and application potentials. However, up to now, no chromatographic methods have been developed to provide full fingerprinting and quality assurance for these saponins. This research aimed to develop a novel method to tentatively identify and quantify saponins in C. sinensis seeds by ultra-high-performance liquid chromatography coupled with photo-diode array detector and quadrupole time-of-flight mass spectrometry (UPLC-PDA-QTOF-MS/MS), and compare it with the classic vanillin-sulfuric acid assay. Fifty-one triterpene saponins, including six potentially new compounds, were simultaneously detected by UPLC-PDA-MS/MS, and their chemical structures were speculated according to the retention behavior and fragmentation pattern. The total saponin content in the crude extract and the purified saponin fraction of C. sinensis seeds were quantified to be 19.57 ± 0.05% (wt %) and 41.68 ± 0.09% (wt %) respectively by UPLC-PDA at 210 nm, while the corresponding values were determined to be 43.11 ± 3.17% (wt %) and 56.60 ± 5.79% (wt %) respectively by the vanillin-sulfuric acid assay. The developed UPLC-PDA -MS/MS method could determine specified saponins, and is more reliable for quantifying the C. sinensis seed saponins than the classic spectrophotometric method. It is of great significance for the future investigations and applications of these saponins.

4.
J Cell Biochem ; 2019 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-31452251

RESUMO

Large intergenic noncoding RNA regulator of reprogramming (Linc-RoR) was first identified as a regulator to increase the emergence of induced pluripotent stem cells through reprogramming differentiated cells and is abnormal expression in a variety of malignant tumors. However, the function of Linc-RoR in pancreatic cancer progression needs further clarification. The data from this study demonstrated that Linc-RoR knockdown suppressed cell proliferative capacity and colony formation, while Linc-RoR overexpression promoted these behaviors. In particular, Linc-RoR overexpression promoted the level of mesenchymal markers, inhibited the expression of epithelial markers, as well as enhanced pancreatic cancer cells migration and invasion, whereas Linc-RoR knockdown inhibited the expression of mesenchymal markers, promoted the expression of epithelial markers, as well as weakened pancreatic cancer cells migration and invasion. Further study revealed that Linc-RoR knockdown brought about a significant fall in YAP phosphorylation and a rise in total YAP, while Linc-RoR overexpression produced the opposite results. Specifically, Linc-RoR promoted YAP in the cytoplasm into the nucleus. Taken together, we conjectured that Linc-RoR promoted proliferation, migration, and invasion of pancreatic cancer cells by activating the Hippo/YAP pathway. YAP might be an underlying target of Linc-RoR and mediate epithelial-mesenchymal transition (EMT) in pancreatic cancer (PC); thus, Linc-RoR might be a very meaningful biomarker for PC.

5.
Poult Sci ; 2019 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-31420658

RESUMO

Laying hens suffer from osteoporosis during their laying period, which causes bone fragility and susceptibility to fracture. This study evaluated the changes of mechanical properties of their bones during the laying period (from 18 to 77 wk) by using nano-indentation, atomic force microscope, X-Ray diffraction, and Raman spectroscopy. Results indicated that the crystallite sizes of bioapatite in femur decreased significantly from 34.45 to 29.26 nm during aging from 18 to 49 wk. Then, the value increased to 37.79 nm at 77 wk. Despite the abundance in bone (usually >50 wt.%), bioapatite mineral content showed no continuous enhancement during aging. The fibrils demonstrated more regular and organized structure during the laying period. Meanwhile the elastic moduli (E) and hardness (H) of femur increased from 10.84 to 18.39 GPa and 43.79 to 97.21 Vickers respectively during this period. The changes in mechanical properties are hence tightly related to the structure of bone (composed of both collagen and mineral), rather than directly related to the mineralogical properties of bone bioapatite. This study addressed the importance of the interaction between collagen and bioapatite mineral during the laying period of hens by microscopic, physicochemical, and mechanical analysis.

6.
J Cell Sci ; 132(17)2019 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-31391241

RESUMO

Internalization of macromolecules and membrane into cells through endocytosis is critical for cellular growth, signaling and plasma membrane (PM) tension homeostasis. Although endocytosis is responsive to both biochemical and physical stimuli, how physical cues modulate endocytic pathways is less understood. Contrary to the accumulating discoveries on the effects of increased PM tension on endocytosis, less is known about how a decrease of PM tension impacts on membrane trafficking. Here, we reveal that an acute decrease of PM tension results in phosphatidic acid (PA) production, F-actin and phosphatidylinositol (4,5)-bisphosphate [PI(4,5)P2]-enriched dorsal membrane ruffling and subsequent macropinocytosis in myoblasts. The PA production induced by decreased PM tension depends on phospholipase D2 (PLD2) activation via PLD2 nanodomain disintegration. Furthermore, the 'decreased PM tension-PLD2-macropinocytosis' pathway is prominent in myotubes, reflecting a potential mechanism of PM tension homeostasis upon intensive muscle stretching and relaxation. Together, we identify a new mechanotransduction pathway that converts an acute decrease in PM tension into PA production and then initiates macropinocytosis via actin and PI(4,5)P2-mediated processes.

7.
Artigo em Inglês | MEDLINE | ID: mdl-31329122

RESUMO

This paper presents a vector painting system for digital artworks. We first propose Temporal Diffusion Curve (TDC), a new form of vector graphics, and a novel random-access solver for modeling the evolution of strokes. With the help of a procedural stroke processing function, the TDC strokes can achieve various shapes and effects for multiple art styles. Based on these, we build a painting system of great potential. Thanks to the random-access solver, our method has real-time performance regardless of the rendering resolution, provides straightforward editing possibilities on strokes both at runtime and afterward, and is effective and straightforward for art production. Compared with the previous Diffusion Curve, our method uses strokes as the basic graphics primitives, which are able to intersect each other and much more consistent with humans' instinct and painting habits. We finally demonstrate that professional artists can create multiple genres of artworks with our painting system.

8.
Anal Chem ; 91(15): 9376-9381, 2019 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-31287298

RESUMO

Frequency-shift based surface-enhanced Raman spectroscopy (SERS) has exhibited great potential applications in bioanalytical chemistry and biomedicine in recent years. The basis and the crucial factors determining frequency shifts are, however, still unclear. Herein, we have systematically investigated how solvents, antigens, and antibodies affect the band shifts in SERS-based immunoassays. By applying the charge transfer theory together with the Stark effect and time-dependent density functional theory (TDDFT) calculation, mechanistic insights into the frequency shifts in immunoreactions is proposed and discussed in detail. Accordingly, the experimental condition is further optimized and is successfully applied for the first time to detect carbonylated proteins, promising diagnostic biomarkers for human diseases. This study provides theoretical guidance for designing SERS frequency shift-based immunoassays and paves a new avenue for further applications of the strategy in clinical diagnosis.

9.
Bioresour Technol ; 289: 121691, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31252318

RESUMO

Zeolites have been widely used as catalysts in the catalytic pyrolysis of biomass to produce biofuels and/or bio-based chemicals, which could lead to the replacement of fossil sources by renewable ones. However, conventional zeolites often suffer from diffusion resistance for large intermediate oxygenates. To solve this problem, a micro/mesoporous core-shell composite zeolite ZSM-5@SBA-15 was prepared and employed as a catalyst in the catalytic pyrolysis of maize straw. ZSM-5@SBA-15 was synthesized by crystallizing mesoporous silica on the external surface of ZSM-5 using the triblock copolymer Plunoric P123 as the template. The core-shell and hierarchical structures were verified using PXRD, TEM, and N2 sorption experiments. In the catalytic pyrolysis of maize straw, ZSM-5@SBA-15 significantly enhanced the yield of valuable phenols and hydrocarbons in bio-oil, compared to ZSM-5 and SBA-15. The results demonstrated the potential application of micro@mesoporous core-shell composite zeolites in the catalytic pyrolysis of biomass.


Assuntos
Hidrocarbonetos/química , Fenol/química , Dióxido de Silício/química , Zea mays/química , Zeolitas/química , Catálise , Hidrocarbonetos/metabolismo , Fenol/metabolismo , Pirólise
10.
Mikrochim Acta ; 186(7): 442, 2019 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-31197467

RESUMO

Silicon nanoparticles (SiNPs) modified with Eu(III) were synthesized and are shown to be a viable ratiometric fluorescent probe for tetracycline antibiotics. SiNPs/Eu under 405 nm excitation display two emissions, viz. a strong cyan colored fluorescence peaking at 497 nm and a weak pink fluorescence peaking at 622 nm. On addition of tetracyclines (chlortetracycline, tetracycline, doxycycline), the fluorescence at 497 nm is reduced, while the one at 622 nm is increased. Thus, the visible color of fluorescence changes from cyan to pink. This was exploited to design ratiometric fluorometric method for detecting tetracyclines. The method has a limit of detection that is lower by a factor of about 1000 when compared to the use of SiNPs only. A test paper was prepared with the SiNPs/Eu and then applied for the visual semi-quantitative detection of tetracyclines. With the addition of tetracyclines, the test paper exhibited a dosage-sensitive color conversion from cyan to pink with a visually discernible scale as low as 0.4 µM. Graphical abstract Tetracyclines decrease the fluorescence at 497 nm of europium (III) modified silicon nanoparticles (SiNPs/Eu) due to the inner filter effect and increase the one at 622 nm due to an antenna effect. Thus the fluorescence color of SiNPs/Eu changes from cyan to pink. Based on this color switch, a ultrasensitive and visual determination strategy for tetracyclines is proposed.

11.
Anal Chem ; 91(14): 8767-8771, 2019 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-31251021

RESUMO

Surface-enhanced Raman spectroscopy (SERS) has exhibited great potential in protein identification and quantification. However, the poor spectral reproducibility, originating from random protein immobilization on SERS substrates, still makes it challenging for SERS to probe protein functions without any extrinsic Raman labels. Here, in our study, spacer molecules between proteins and SERS substrates are optimized for both biocompatible protein immobilization and Raman scattering enhancement. We have accordingly prepared iminodiacetic acid (IDA)-functionalized silver substrates, which are used for capturing His-tagged proteins via nickel-imidazole coordination. The controlled immobilization enables excellent SERS spectral reproducibility as evidenced by 6 polypeptides. Furthermore, the interactions between two model proteins, Erv1C (C-terminal domain of flavine adenine dinucleotide-dependent mitochondrial cytochrome c reductase Erv1) and AFP (alpha-fetoprotein), and their ligands Cyt c (cytochrome c) and ATRA (all-trans-retinoic acid) are examined, respectively. The results indicate that the IDA-functionalized silver substrates enable controlled protein immobilization and allow label-free protein function investigation by SERS. As a proof-of-concept study, the proposed functionalized SERS-active substrates combined with immobilized metal-affinity chromatography will be useful for mechanism studies on protein-ligand interactions, which is crucially important for understanding the structural basis of protein functional versatility and will contribute to the fields of drug design and biotechnology.

12.
J Integr Plant Biol ; 2019 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-31087765

RESUMO

Maize (Zea mays L.) is a monoecious grass plant in which mature male and female florets form the tassel and ear, respectively. Maize is often used as a model plant to study flower development. Several maize tassel seed mutants, such as the recessive mutants tasselseed1 (ts1) and tasselseed2 (ts2), exhibit a reversal in sex determination, which leads to the generation of seeds in tassels. The phenotype of the dominant mutant, Tasselseed5 (Ts5), is similar to that of ts2. Here, we positionally cloned the underlying gene of Ts5 and characterized its function. We show that the GRMZM2G177668 gene is overexpressed in Ts5. This gene encodes a cytochrome C oxidase, which catalyzes the transformation of jasmonoyl-L-isoleucine (JA-Ile) to 12OH-JA-Ile during jasmonic acid catabolism. Consistent with this finding, no JA-Ile peak was detected in Ts5 tassels during the sex determination period, unlike in the wild type. Transgenic maize plants overexpressing GRMZM2G177668 exhibited a tassel-seed phenotype similar to that of Ts5. These results indicate that the JA-Ile peak in tassels is critical for sex determination and that the Ts5 mutant phenotype results from the disruption of this peak in tassels during sex determination.

13.
J Hazard Mater ; 377: 24-33, 2019 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-31132678

RESUMO

Tar formation during biomass gasification is undesirable due to the decreased energy efficiency and increased costs for maintaining downstream equipment. The hybrid non-thermal plasma-catalysis method is considered to be a promising alternative, since it overcomes the disadvantages arising from both catalyst deactivation during catalytic reforming and the formation of undesirable liquid by-products in plasma reforming. SiO2- and ZSM-5-supported Ni-based catalysts with different Ni loadings (0.5, 1, 3, and 5 wt%) were prepared by thermal fusion and applied to the steam reforming of toluene. Different characterizations of fresh and spent catalysts including XRD, H2-TPR, N2 adsorption-desorption, SEM, TEM, XPS and TGA were conducted to show the properties of catalysts. The results indicated that Ni/ZSM-5 exhibited better performance than Ni/SiO2, due to the increased dispersion of Ni particles and the stronger metal-support interaction of Ni/ZSM-5, which was confirmed by the TEM and H2-TPR results. In addition, the performances of the catalysis-only (CatO), plasma-only (PlO), and in-plasma-catalysis (IPC) systems in steam reforming of different model tar compounds including benzene, toluene, furfural, naphthalene, fluorene and pyrene were compared using Ni(5 wt%)/ZSM-5. Obvious synergistic effects between DBD plasma and Ni(5 wt%)/ZSM-5 was observed for syngas production in the IPC system.

14.
New Phytol ; 223(3): 1407-1419, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31009078

RESUMO

BRI1-EMS-SUPPRESSOR 1 (BES1) functions as a key regulator in the brassinosteroid (BR) pathway that promotes plant growth. However, whether BES1 is involved in photoperiodic flowering is unknown. Here we report that BES1 acts as a positive regulator of photoperiodic flowering, but it cannot directly bind FLOWERING LOCUS T (FT) promoter. BR ENHANCED EXPRESSION 1 (BEE1) is the direct target of BES1 and acts downstream of BES1. BEE1 is also a positive regulator of photoperiodic flowering. BEE1 binds directly to the FT chromatin to activate the transcription of FT and promote flowering initiation. More importantly, BEE1 promotes flowering in a blue light photoreceptor CRYPTOCHROME 2 (CRY2)  partially dependent manner, as it physically interacts with CRY2 under the blue light. Furthermore, BEE1 is regulated by both BRs and blue light. The transcription of BEE1 is induced by BRs, and the BEE1 protein is stabilized under the blue light. Our findings indicate that BEE1 is the integrator of BES1 and CRY2 mediating flowering, and BES1-BEE1-FT is a new signaling pathway in regulating photoperiodic flowering.

15.
Anal Chem ; 91(10): 6872-6879, 2019 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-31001973

RESUMO

Peroxynitrite (ONOO-) is attracting increasing attention due to its involvement in multiple facets of pathophysiological processes. However, ONOO- bioimaging is still challenging due to (1) the lack of highly specific reaction triggers, (2) the tedious and low-yielding synthesis of current sophisticated probes, and (3) the lack of availability of a versatile chemical strategy. To address these challenges, on the basis of amine formylation/deformylation chemistry, we have developed a novel strategy for ONOO- bioimaging. As proof of principle, we designed, synthesized, and evaluated four novel fluorescent probes equipped with the formamide functionality. Although they feature distinctly different fluorophore classes, all probes can be synthesized in one step in high yields and exhibit particularly specific, highly sensitive, and rapid responses to ONOO-. The bioimaging capability is well demonstrated by successfully visualizing ONOO- fluctuation in live cells and major organs of mice suffering from paraquat poisoning. The proposed strategy has proved to be a facile, versatile, and highly efficient methodology for ONOO- visualization, which will greatly facilitate ONOO- biochemistry and pathophysiology.

16.
J Cell Biol ; 218(5): 1670-1685, 2019 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-30894403

RESUMO

Skeletal muscle development requires the cell-cell fusion of differentiated myoblasts to form muscle fibers. The actin cytoskeleton is known to be the main driving force for myoblast fusion; however, how actin is organized to direct intercellular fusion remains unclear. Here we show that an actin- and dynamin-2-enriched protrusive structure, the invadosome, is required for the fusion process of myogenesis. Upon differentiation, myoblasts acquire the ability to form invadosomes through isoform switching of a critical invadosome scaffold protein, Tks5. Tks5 directly interacts with and recruits dynamin-2 to the invadosome and regulates its assembly around actin filaments to strengthen the stiffness of dynamin-actin bundles and invadosomes. These findings provide a mechanistic framework for the acquisition of myogenic fusion machinery during myogenesis and reveal a novel structural function for Tks5 and dynamin-2 in organizing actin filaments in the invadosome to drive membrane fusion.

17.
Health Qual Life Outcomes ; 17(1): 47, 2019 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-30876410

RESUMO

BACKGROUND: Cold climates traditionally have conferred long sleep duration in the residents in northeast China; however, modern lifestyle reduces sleep duration. In this study, we investigated social-biological factors influencing sleep duration in the adult residents in northeast China. METHODS: This study was performed using data from the Investigation of Chronic Disease Morbidity Rate and Risk Factors of Adults in Jilin Province, China. Associations between sleep duration and indices of demographic characteristics, health-related behaviors, and disease history in adult residents were analyzed using univariate analysis and multivariate logistic regression analysis. RESULTS: The mean sleep duration was 7.24 h. Of the 21,435 participants, approximately 53.4% had short sleep duration (sleep duration per day < 7 h), and 10.5% had long sleep duration (sleep duration per day > 9 h). There were associations between short sleep duration and indices, including age, place of residence, marital status, educational level, alcohol drinking, dietary, obesity, and history of coronary heart disease (CHD) or myocardial infarction (MI). There existed associations of long sleep duration with indices, such as age, place of residence, occupation, educational level, average monthly earnings, and physical exercise. CONCLUSION: Short sleep duration is common among residents in northeast China. Age, place of residence, and educational level are implicated in both short sleep duration and long sleep duration. Short sleep duration inclines to link with the indices (marital status, alcohol drinking, dietary, obesity, and history of CHD or MI). However, long sleep duration is relevant to the indices (occupation, average monthly earnings, and physical exercise).


Assuntos
Privação do Sono/epidemiologia , Sono/fisiologia , Fatores Socioeconômicos , Adulto , Fatores Etários , Idoso , China , Estudos Transversais , Exercício , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Qualidade de Vida , Fatores de Risco , Inquéritos e Questionários , Fatores de Tempo , Adulto Jovem
18.
Autism Res ; 12(3): 375-383, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30629339

RESUMO

Autism spectrum disorder (ASD) is a serious lifelong neurodevelopmental disorder. ASD is diagnosed for children at the age of two. ASD diagnosis, as early as possible, lays the foundation for treatment and much better prognosis. Notably, gene-based test is an inherent method to recognize the potential infants with ASD before the age of two. To investigate whether SHANK family contributes to ASD prediction, on the basis of our previous studies of SHANK2 and SHANK3, we further investigated associations between SHANK1 polymorphisms and ASD risk as well as SNP-SNP interactions among SHANK family. We enrolled 470 subjects (229 cases and 241 healthy controls) who were northeast Chinese Han. Four tag SNPs (rs73042561, rs3745521, rs4801846, and rs12461427) of SHANK1 were selected and genotyped. We used the SNPStats online analysis program to assess the associations between the four SNPs and ASD risk. The SNP-SNP interactions among SHANK family were analyzed using multifactor dimensionality reduction method. We found that the four SHANK1 SNPs were not associated with ASD risk in northeast Chinese Han population. There existed a strong synergistic interaction between rs11236697 [SHANK2] and rs74336682 [SHANK2], and moderate synergistic interactions (rs74336682 [SHANK2]-rs73042561 [SHANK1], rs11236697 [SHANK2]-rs77716438 [SHANK2], and rs11236697 [SHANK2]-rs75357229 [SHANK2]). These SHANK1 variants may not affect the susceptibility to ASD in Chinese Han population. SNP-SNP interactions in SHANK family may confer ASD risk. Autism Res 2019, 12: 375-383 © 2019 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: ASD is a serious lifelong neurodevelopmental disorder with strong genetic components. We investigated associations between SHANK1 polymorphisms and ASD risk as well as SNP-SNP interactions among SHANK family. Our results indicated that there exists no association between SHANK1 SNPs and ASD, and SNP-SNP interactions in SHANK family may confer ASD risk in the Northeast Han Chinese population. Future studies are needed to test more SHANK family SNPs in a large sample to demonstrate the associations.

19.
Spectrochim Acta A Mol Biomol Spectrosc ; 207: 307-312, 2019 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-30265946

RESUMO

Norfloxacin (NFX) is an antibacterial agent belonging to the fluoroquinolone family of drugs, known to bind bovine serum albumin (BSA). Surface-enhanced Raman scattering (SERS) and fluorescence spectroscopy in combination with molecular docking were explored to investigate the binding interaction between NFX with Bovine serum albumin (BSA) at a physiological condition. This study focused on identifying the binding site and relevant interaction mechanisms between NFX and BSA. Spectrophotometric titration with molecular docking results demonstrated that the binding site of NFX on BSA was located in sub-domain IIA. The principle binding site was identified within a hydrophobic cavity which is surrounded by the residues Leu 197, Arg 198, Ser 201, Ala 209, Trp 213, Ser 343, Leu 346, Lys 350, Ser 453, Leu 480, Val 481, and the binding force was mainly hydrophobic interaction and hydrogen bond interaction. In addition, the absorptive orientation of the NFX molecule on the colloidal surface underwent a set of changes during the process of NFX binding to BSA.


Assuntos
Antibacterianos/metabolismo , Norfloxacino/metabolismo , Soroalbumina Bovina/metabolismo , Animais , Sítios de Ligação , Bovinos , Ligações de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Simulação de Acoplamento Molecular , Ligação Proteica , Soroalbumina Bovina/química , Análise Espectral Raman
20.
J Hazard Mater ; 366: 538-544, 2019 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-30572293

RESUMO

Novel bimetallic catalysts supported on activated carbon (AC) with high metal loadings were synthesized by carbonizing an ion-exchange resin. AC-supported Ni-Cu (Ni-Cu/C) and Ni-Zn (Ni-Zn/C) bimetallic catalysts with different Ni:Cu(Zn) ratios were used to decompose Aroclor 1254, which is a commonly used commercial mixture of polychlorinated biphenyls. Characterization with scanning electron microscopy and energydispersive X-ray spectroscopy showed that the metals were uniformly distributed on the surfaces and inside the catalysts. After 30 min reaction over the Ni-Cu/C catalyst at a low temperature of 250 °C, the efficiencies of Hexa-CBs decomposition present in Aroclor 1254 exceeded 97%, which were higher than those achieved over Ni-Zn/C. These efficiencies increased with Cu content in Ni-Cu/C, and decreased with the amount of Zn in Ni-Zn/C. X-ray photoelectron spectra and X-ray absorption near-edge structure spectra of Ni-Cu/C and Ni-Zn/C before and after the reaction indicated that Ni and Cu were oxidized during the reaction. However, Zn showed no significant change, suggesting that Ni and Cu are the active components to promote reaction with Aroclor 1254, whereas Zn is only a spectator. The efficiencies of Aroclor 1254 decomposition over bimetallic catalysts were greater than those over monometallic catalysts, which was confirmed by density functional theory calculations.

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