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1.
Aging (Albany NY) ; 12(9): 8549-8564, 2020 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-32391804

RESUMO

Gastric cancer (GC) is one of the most common malignancies worldwide manifesting high morbidity and mortality. Cancer-associated fibroblasts (CAFs), important components of the tumor microenvironment, are essential for tumorigenesis and progression. Exosomes secreted from CAFs have been reported as the critical molecule-vehicle in intercellular crosstalk. However, the precise mechanism underlying the effect of CAFs remains to be fully investigated. In this study, we aimed to determine the role of CAFs and their exosomes in the progression of GC and related mechanisms. The results revealed that miRNA-34 was downregulated in both GC fibroblasts (GCFs) and GC cell lines while the overexpression of miRNA-34 suppressed the proliferation, invasion, and motility of GC cell lines. Coculturing GC cells with miRNA-34-overexpressing GCFs led to the suppression of cancer progression. Also, exosomes derived from GCFs were taken up by GC cells in vitro and in vivo and exerted antitumor roles in GC. In addition, exosomal miRNA-34 inhibited GC cell proliferation and invasion in vitro and suppressed tumor growth in vivo. Furthermore, 16 genes were identified as potential downstream targeting genes of miRNA-34. Taken together, GCFs-derived exosomal miRNA-34 may be a promising targeting molecule for therapeutic strategies in GC.

2.
Biomed Pharmacother ; 127: 110195, 2020 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-32361161

RESUMO

Since early December 2019, a number of pneumonia cases associated with unknown coronavirus infection were identified in Wuhan, China, and many additional cases were identified in other regions of China and in other countries within 3 months. Currently, more than 80,000 cases have been diagnosed in China, including more than 3000 deaths. The epidemic is spreading to the rest of the world, posing a grave challenge to prevention and control. On February 12, 2020, the International Committee on Taxonomy of Viruses and the World Health Organization officially named the novel coronavirus and associated pneumonia as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and coronavirus disease 2019 (COVID-19), respectively. According to the recent research on SARS-CoV-2, the virus mainly infects the respiratory system but may cause damage to other systems. In this paper, we will systematically review the pathogenic features, transmission routes, and infection mechanisms of SARS-CoV-2, as well as any adverse effects on the digestive system, urogenital system, central nervous system, and circulatory system, in order to provide a theoretical and clinical basis for the diagnosis, classification, treatment, and prognosis assessment of SARS-CoV-2 infection.

3.
Food Funct ; 2020 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-32347864

RESUMO

Gastric cancer is the fourth most common cancer and the second most frequent cause of cancer death worldwide. Chemotherapy is an important treatment. However, traditional chemotherapy drugs have low bioavailability and targeting ability. Therefore, we developed curcumin-encapsulated micelles for the treatment of gastric cancer and investigated their antitumor efficacy and active mechanism. Gastric cancer cells were treated with different concentrations of curcumin micelles. MTS cell proliferation assays, flow cytometry (FCM), real time cellular analysis (RTCA) and nude mice xenografts were used to evaluate the effects of curcumin micelles on gastric cancer cell growth in vitro and in vivo. Western blotting was performed to analyze the protein levels of the indicated molecules. A Seahorse bioenergetics analyzer was used to investigate alterations in oxygen consumption and the aerobic glycolysis rate. Curcumin micelles significantly inhibited proliferation and colony formation and induced apoptosis in gastric tumor cells compared to the control groups. We further investigated the mechanism of curcumin micelles on gastric tumor cells and demonstrated that curcumin micelles acted on mitochondrial proteins, causing changes in mitochondrial function and affecting mitochondrial bioenergetics. Furthermore, curcumin micelles decreased mitochondrial membrane potential, increased reactive oxygen species (ROS) generation and disrupted redox equilibrium. The nude mouse model verified that curcumin micelle treatment significantly attenuated tumor growth in vivo. Curcumin micelles suppress gastric tumor cell growth in vitro and in vivo. The mechanism may be related to increasing ROS generation, disrupting redox equilibrium and affecting mitochondrial bioenergetics.

4.
Pak J Pharm Sci ; 33(2): 669-674, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32276913

RESUMO

Analysis of the constituents of the chloroform extract of Oxytropis falcata Bunge (CEOF), a traditional Tibetan medicine, in rat's serum after oral administration, has been performed by HPLC-MS. We have identified 10 compounds in CEOF and 11 bioactive ingredients from rat's serum after given CEOF. Six bioactive ingredients from rat's serum are matched with original form of the compounds of CEOF. Other five bioactive ingredients were seemed to be respectively metabolites. HPLC-MS is rapid, sensitive method and suitable for identification of bioactive components absorbed into blood of CEOF providing information for further research of pharmacological mechanism.

5.
Urology ; 2020 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-32325140

RESUMO

High-pressure chronic retention (HPCR) is a well-recognized common urological emergency which requires prompt treatment. It usually presents with nocturnal enuresis, a tense and palpable bladder, and symptoms of uraemia from renal failure George et al 1983.1 There have been isolated cases in the literature of HPCR presenting with symptoms of venous occlusion secondary to extrinsic bladder compression2,3 but it remains a rare presenting complaint. We discuss the case of a 56-year-old man who presented primarily with right lower limb swelling which was later revealed to be due to HPCR.

6.
Int J Oncol ; 57(1): 67-79, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32319596

RESUMO

Glioma is the most common primary tumour of the central nervous system, and is associated with a high postoperative recurrence rate and resistance to chemotherapy. High­grade glioblastoma in particular has a very poor prognosis and poses a serious threat to human health. Related studies have confirmed that the occurrence and development of gliomas are closely associated with the abnormal expression and regulation of genes. Moreover, the number of studies on the association of the expression of non­coding RNAs [linear RNAs, microRNAs and circular RNAs (circRNAs)] in human cells with glioma has been gradually increasing in recent years. Among those, circRNAs, previously considered to be 'splicing errors', have been shown to be highly expressed in eukaryotic cells and regulate the biological behaviour of gliomas. circRNAs are highly abundant and stable, and have become a research hotspot in the field of glioma molecular biology. The aim of the present review was to focus on the research progress regarding the association between circRNA expression and gliomas, and to provide a theoretical basis according to the currently available literature for further exploring this association. The present study may be of value for the early diagnosis, pathological grading, targeted therapy and prognostic evaluation of gliomas.

7.
Materials (Basel) ; 13(7)2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32244673

RESUMO

A composite coating with enhanced mechanical properties including high hardness and excellent wear resistance was produced by laser cladding of mixed Ni45 and high-carbon ferrochrome powders on an ASTM 1045 steel substrate. Different quantities, ranging from 10 to 50 wt.% of high-carbon ferrochrome powder were added to the Ni45 powder to investigate the effect of mixture content on the cladding performance. The microstructure of the coatings were examined using scanning electron microscope, and the wear resistance was compared using a wear tester apparatus among the different cases. The results showed that the microstructure of the coating with 30 wt.% high-carbon ferrochrome content was mainly fine solid solution phase. With the increase of high-carbon ferrochrome content to 40 wt.% and above, cracks appeared on the cladding surface due to a large amount of chromium carbides formed during the process. The microhardness was enhanced remarkably by laser cladding the composite coating on the 1045 substrate, with 2.4 times higher than the hardness of the substrate when 30 wt.% high-carbon ferrochrome content was added. The best wear performance was achieved when the high-carbon ferrochrome content was 30 wt.%, demonstrating the smallest surface roughness and depth of wear marks. With further increased high-carbon ferrochrome content, microcracking and delamination were observed on the worn surfaces.

8.
Carbohydr Polym ; 238: 116180, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32299561

RESUMO

In this study, the lemon (Citrus limon) seeds as typical agricultural processing wastes were utilized to extract cellulose nanocrystals (CNCs) by sulfuric acid hydrolysis (S-LSCNC), ammonium persulfate oxidation (A-LSCNC) and TEMPO oxidation (T-LSCNC). The properties of CNCs were comparatively investigated by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), thermogravimetric analysis (TG), and atomic force microscope (AFM), and the application in Pickering emulsions was also preliminarily studied. The results showed that all CNCs maintained cellulose Iß structure and had a good dispersion regardless of extraction methods. Differently, T-LSCNC had a higher yield, larger size and lower CrI than A-LSCNC and S-LSCNC. Comparatively, A-LSCNC showed the highest CrI and S-LSCNC showed the lowest size. For the application of Pickering emulsions, S-LSCNC and A-LSCNC showed a better ability as Pickering stabilizers than T-LSCNC. This study is beneficial for developing the potential utilization of CNCs from lemon by-products.

9.
J Pharm Biomed Anal ; 184: 113197, 2020 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-32120187

RESUMO

Untargeted mass spectrometry analysis is one of the most challenging and meaningful steps in the rapid structural elucidation of the highly complex and diverse constituents of traditional Chinese medicine. Specifically, it is a laborious and time-consuming way to identify unknown compounds. Herein, a workflow was proposed to expedite the annotations of the chemical structures in Pheretima aspergillum (E. Perrier) (Di-Long, DL). First, ultra high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-QTOFMS) was performed to obtain the untargeted mass spectral data. Then, the spectral data were uploaded to the Global Natural Products Social Molecular Networking (GNPS) platform to create a network and extract the Mass2Motifs (co-occurring fragments and neutral losses) using unsupervised substructure annotation topic modeling (MS2LDA). Finally, a structural analysis was performed using the proposed workflow of MS2LDA in combination with mass spectral molecular networking and in silico fragmentation prediction. As a result, a total of 124 compounds from DL were effectively characterized, of which 89 (7 furan sulfonic acids, 57 phospholipids and 25 carboxamides) were identified as potentially new compounds from DL. The results presented in this article significantly improve the understanding of the chemical composition of DL and provide a solid scientific basis for the future study of the quality control, underlying pharmacology and mechanism of DL. Moreover, the proposed workflow was used for the first time to accelerate the annotations of unknown molecules from TCM. Furthermore, this workflow will increase the efficiency of characterizing the 'unknown knowns' and elucidation of the 'unknown unknowns' from TCM, which are crucial steps of discovering the natural product drugs in TCM.

10.
Cell Death Dis ; 11(3): 183, 2020 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-32170066

RESUMO

Exposure to nanomaterials (NMs) is an emerging threat to human health, and the understanding of their intracellular behavior and related toxic effects is urgently needed. Ferroptosis is a newly discovered, iron-mediated cell death that is distinctive from apoptosis or other cell-death pathways. No evidence currently exists for the effect of "iron free" engineered NMs on ferroptosis. We showed by several approaches that (1) zinc oxide nanoparticles (ZnO NPs)-induced cell death involves ferroptosis; (2) ZnO NPs-triggered ferroptosis is associated with elevation of reactive oxygen species (ROS) and lipid peroxidation, along with depletion of glutathione (GSH) and downregulation of glutathione peroxidase 4 (GPx4); (3) ZnO NPs disrupt intracellular iron homeostasis by orchestrating iron uptake, storage and export; (4) p53 largely participates in ZnO NPs-induced ferroptosis; and (5) ZnO particle remnants and dissolved zinc ion both contribute to ferroptosis. In conclusion, our data provide a new mechanistic rationale for ferroptosis as a novel cell-death phenotype induced by engineered NMs.

11.
Oxid Med Cell Longev ; 2020: 3690123, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32064022

RESUMO

Thioridazine (THIO) is a phenothiazine derivative that is mainly used for the treatment of psychotic disorders. However, cardiac arrhythmias especially QT interval prolongation associated with the application of this compound have received serious attention after its introduction into clinical practice, and the mechanisms underlying the cardiotoxicity induced by THIO have not been well defined. The present study was aimed at exploring the long-term effects of THIO on the hERG and L-type calcium channels, both of which are relevant to the development of QT prolongation. The hERG current (I hERG) and the calcium current (I Ca-L) were measured by patch clamp techniques. Protein levels were analyzed by Western blot, and channel-chaperone interactions were determined by coimmunoprecipitation. Reactive oxygen species (ROS) were determined by flow cytometry and laser scanning confocal microscopy. Our results demonstrated that THIO induced hERG channel deficiency but did not alter channel kinetics. THIO promoted ROS production and stimulated endoplasmic reticulum (ER) stress and the related proteins. The ROS scavenger N-acetyl cysteine (NAC) significantly attenuated hERG reduction induced by THIO and abolished the upregulation of ER stress marker proteins. Meanwhile, THIO increased the degradation of hERG channels via disrupting hERG-Hsp70 interactions. The disordered hERG proteins were degraded in proteasomes after ubiquitin modification. On the other hand, THIO increased I Ca-L density and intracellular Ca2+ ([Ca2+]i) in neonatal rat ventricular cardiomyocytes (NRVMs). The specific CaMKII inhibitor KN-93 attenuated the intracellular Ca2+ overload, indicating that ROS-mediated CaMKII activation promoted calcium channel activation induced by THIO. Optical mapping analysis demonstrated the slowing effects of THIO on cardiac repolarization in mouse hearts. THIO significantly prolonged APD50 and APD90 and increased the incidence of early afterdepolarizations (EADs). In human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs), THIO also resulted in APD prolongation. In conclusion, dysfunction of hERG channel proteins and activation of L-type calcium channels via ROS production might be the ionic mechanisms for QT prolongation induced by THIO.

12.
Carbohydr Polym ; 230: 115599, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31887921

RESUMO

Herein, the hierarchically processed pineapple peel was achieved by water (WT-PP), alkali (AT-PP), bleaching (BT-PP) and bleaching-alkali (PPC) treatments respectively for separate or simultaneous removal of hemicellulose and lignin. These treated pineapple peel were further fabricated into hydrogels (WT-PPH, AT-PPH, BT-PPH and PPCH, respectively) by a facile dissolution-regeneration process in ionic liquid. The structure and Congo red (CR) adsorption ability of the hydrogels were investigated and compared. The adsorption process conformed better to the pseudo-second-order kinetic and Langmuir isotherm models. The maximum adsorption capacity was 114.94 mg/g for WT-PPH, 77.52 mg/g for AT-PPH, 138.89 mg/g for BT-PPH and 75.19 mg/g for PPCH, implying the separate bleaching treatment could improve the CR adsorption capacity more. Moreover, the hydrogels displayed a pH-dependent behavior and good reusability during adsorption process. Based on removal of initial components and simple preparation method, this work would be beneficial for the development of agricultural residues-based biosorbents.

13.
J Environ Manage ; 258: 109946, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31929044

RESUMO

Environmental pollutants generated by waste incineration plants, such as heavy metals and dioxin, make surrounding residents very sensitive to the construction of such facilities. This sensitivity and anxiety of residents may induce group events, which further leads to the emergence of social risks. Based on risk perception theory, a total of 320 questionnaires was designed and handed out to residents neighboring to Jiangqiao Waste Incineration Plant in Shanghai, China to detect the factors affecting risk attitude toward such plants. Using ordered logit model, it is found that there are four decisive factors including impact on health, information cognitive, objective characteristics, and the attitude of the neighbors. These factors have different influence on resident risk attitudes, in which the attitude of the neighbors is of most significance, followed by the economic-geography characteristics of residents, the information cognitive has minimal impact.


Assuntos
Dioxinas , Eliminação de Resíduos , Gerenciamento de Resíduos , Atitude , China , Incineração , Risco
14.
Endocrine ; 67(1): 224-232, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31325086

RESUMO

Kallmann syndrome (KS) is a congenital hypogonadotropic hypogonadism that coincides with anosmia or hyposmia. Although this rare genetic disease has a very low incidence, it harbors a complicated genetic heterogeneity, which indicates X-linked, autosomal, and oligogenic inheritance of puberty, sexuality, reproductivity, and olfactory defects. There has been limited elucidation of molecular etiologies completed to date. Here, a chromosome reciprocal translocation (46, XX, t (3; 13) (p13; q22)) was identified in a 27-year-old Chinese female diagnosed with KS. Genome sequencing found an intronic breakpoint of SCEL in chromosome 13 and an intergenic breakpoint between ROBO1 and ROBO2 in chromosome 3. This translocation resulted in the reduced expression levels of these genes. An array-CGH test captured no abnormal genomic copy numbers of clinical significance. The basic features of all known KS-related genes were also reviewed and analyzed for their roles in KS onset with bioinformatic methods. Signal pathway and gene enrichment analysis of KS-related genes suggested that these genes have integrated functions in neuronal migration and differentiation. An interesting chromosome locational pattern of KS-related genes was also discovered. This study provided constructive clues for further investigations into the molecular etiology of KS.

15.
J Biochem Mol Toxicol ; 34(2): e22423, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31729781

RESUMO

MicroRNAs are endogenous small noncoding RNAs that posttranscriptionally regulate the expression of target genes and play crucial roles in diverse physiopathologic processes. In the current study, we examined the microRNA (miRNA) expression profile of high-glucose-treated neonatal rat cardiomyocytes and the potential mechanisms. Differentially expressed miRNAs were analyzed by a miRNA microarray and validated by a quantitative real-time polymerase chain reaction in high-glucose-treated rat cardiomyocytes. Based on the results of our previous study and the bioinformatics prediction, we identified miR-195-5p/SGK1/Nedd4-2/hERG as the top-ranked signal pathway in diabetes cell model in vitro. In summary, our present study provides novel insights into the regulatory mechanism of miR-195-5p/SGK1/Nedd4-2/hERG in rat cardiomyocytes under high-glucose stress, which may provide a novel idea for the development of diagnostic and therapeutic strategies for diabetic cardiomyopathy in the future.


Assuntos
Cardiomiopatias Diabéticas/metabolismo , Glucose/farmacologia , MicroRNAs/genética , Miócitos Cardíacos/efeitos dos fármacos , Transcriptoma , Regiões 3' não Traduzidas/genética , Animais , Sítios de Ligação , Canal de Potássio ERG1/antagonistas & inibidores , Canal de Potássio ERG1/metabolismo , Feminino , Técnicas de Silenciamento de Genes , Células HEK293 , Humanos , Proteínas Imediatamente Precoces/antagonistas & inibidores , Proteínas Imediatamente Precoces/metabolismo , Masculino , Miócitos Cardíacos/metabolismo , Ubiquitina-Proteína Ligases Nedd4/metabolismo , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Proteínas Serina-Treonina Quinases/metabolismo , Ratos , Ratos Sprague-Dawley , Transfecção
16.
Epigenomics ; 12(3): 267-283, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31808351

RESUMO

Aim: This review aims to systematically describe the biogenesis and degradation of circular RNAs (circRNAs), discusses the major functions of circRNAs, introduces the mechanisms by which circRNAs play a role in cancer, comprehensively summarize the relationship between circRNAs and anticarcinogen resistance as well as underlying specific mechanisms in multiple cancers. Materials & methods: We screened and analyzed large quantity of scientific papers which associated with circRNAs, noncoding RNAs, function, cancer, drug resistance and chemoresistance, and then summarized in Figures 1 & 2 & Table 1. Results & conclusion: The biogenesis, degradation and function of circRNAs are specially compared with other noncoding RNAs, it can affect cancer pathogenesis and progression and are implicated in mediating resistance to various anticarcinogens in various types of cancer.

17.
Curr Pharm Des ; 25(43): 4606-4612, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31657676

RESUMO

BACKGROUND: The human ether-a-go-go-related gene (hERG) potassium channel is the rapidly activating component of cardiac delayed rectifier potassium current (IKr), which is a crucial determinant of cardiac repolarization. The reduction of hERG current is commonly believed to cause Long QT Syndrome (LQTs). Probucol, a cholesterol-lowering drug, induces LQTs by inhibiting the expression of the hERG channel. Unfortunately, there is currently no effective therapeutic method to rescue probucol-induced LQTs. METHODS: Patch-clamp recording techniques were used to detect the action potential duration (APD) and current of hERG. Western blot was performed to measure the expression levels of proteins. RESULTS: In this study, we demonstrated that 1 µM matrine and oxymatrine could rescue the hERG current and hERG surface expression inhibited by probucol. In addition, matrine and oxymatrine significantly shortened the prolonged action potential duration induced by probucol in neonatal cardiac myocytes. We proposed a novel mechanism underlying the probucol induced decrease in the expression of transcription factor Specificity protein 1 (Sp1), which is an established transactivator of the hERG gene. We also demonstrated that matrine and oxymatrine were able to upregulate Sp1 expression which may be one of the possible mechanisms by which matrine and oxymatrine rescued probucol-induced hERG channel deficiency. CONCLUSION: Our current results demonstrate that matrine and oxymatrine could rescue probucol-induced hERG deficiency in vitro, which may lead to potentially effective therapeutic drugs for treating acquired LQT2 by probucol in the future.

18.
Brain Res Bull ; 154: 135-141, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31715314

RESUMO

Brain ischemia leads to insufficient oxygen supply or hypoxia and thus to ischemic stroke or chronic hypoperfusion, which results in neuronal death and white matter damage is irreversible or partially recoverable under the interruption of blood flow more than a few minutes. The present study investigated the abnormal characteristics of white matter integrity after the chronic cerebral ischemia in a mouse model of bilateral carotid artery stenosis and the acute cerebral ischemia in a mouse model of middle cerebral artery occlusion via longitudinal diffusion tensor imaging, which revealed that the mean diffusivity of corpus callosum (cc) was decreased as early as the 1 st day after chronic cerebral ischemia, and then the damage gradually aggravated and lasted to the 28th day. Moreover, the brain regions, including cingulum (cg), dorsal hippocampal commissure (dhc), forceps major of the corpus callosum (fmj), alveus of the hippocampus (alv) and medial lemniscus (ml), were damaged in duration of 7∼28 days after chronic cerebral ischemia. Oppositely, white matter signals in the contralateral hemisphere appeared compensatory increase in the internal capsule (ic) at the 1 st day after acute cerebral ischemia, simultaneously the ipsilateral hemisphere signals were decreased in alv, cerebral peduncle (cp), external capsule (ec), ml, fimbria of the hippocampus (fi), ic, forceps minor of the corpus callosum (fmi) and dhc. While these regional white matter signals were decreased in the bilateral hemisphere at the 7th day after acute cerebral ischemia. In addition, the motor function was impaired after acute cerebral ischemia, and cognitive function were impaired after chronic and acute cerebral ischemia. Furthermore, voxel-wise analysis revealed the obvious differences of white matter integrity in these two models of ischemia. The chronic cerebral ischemia showed better white matter integrity in the ipsilateral hemisphere of acute cerebral ischemic model at the 1 st day after surgery, but worse in the contralateral hemisphere. Subsequently, these differences were reduced significantly and just only the ipsilateral cp and bilateral ml signals were higher in chronic cerebral ischemia. Taken together, the present study demonstrates that the chronic and acute cerebral ischemia cause progressive damages of white matter that are irreversible in a relatively long time, of which the contralateral white matter present transient compensation in acute cerebral ischemia but not in chronic cerebral ischemia. These might be helpful to better diagnosis of clinical different cerebral ischemia.

19.
Spectrochim Acta A Mol Biomol Spectrosc ; 229: 117937, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31865099

RESUMO

Polyphenols have been known to have significant binding affinity for proteins, and the specific condition (such as pH) could affect the degree of binding, the formation of covalent bond, and non-covalent interaction. In this study, characteristics of binding quercetin (Q) to wheat gliadin (G) which is a strong food allergen, were studied from pH 2.0 to pH 9.0. The results showed that Q quenched the fluorescence intensity of G by dynamic and static quenching modes and the stoichiometry of binding was close to 1. Intermolecular binding distances were smaller than 8 nm. Thermodynamic parameters suggested that hydrophobic force took charge of the formation of complexes at pH 2.0-4.0, whereas hydrogen bonds and van der Waals forces at pH 5.0-9.0. Analyses of the Fourier transform infrared and the Raman spectra along with synchronous fluorescence spectra revealed secondary and tertiary structural alterations and microenvironmental changed around protein fluorophores upon complexation with Q. The gauche-gauche-trans conformation increased at the expenses of the gauche-gauche-gauche conformation and the transition from ß-turn and random coil to α-helix and ß-sheet at pH 5.0 might decrease the allergenicity of G. These results provided new insights into G/Q interactions at different pH values, which may have potentials in decreasing allergen immunoreactivity.

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