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Dingqiang Lu, Fuping Lu, Guangchang Pang
In the current study, a novel double-layer gold nanoparticles-electrochemical immunosensor electrode immobilized with tetrahydrocannabinol (THC) antibody derived from Balb/c mice was developed. To increase the fixed quantity of antibodies and electrochemical signals, an electrochemical biosensing signal amplification system was utilized with gold nanoparticles-thionine-chitosan absorbing horseradish peroxidase (HRP). In addition, a transmission electron microscope (TEM) was used to characterize the nanogold solution...
October 17, 2016: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Qinghua Xu, Chaoliang He, Zhen Zhang, Kaixuan Ren, Xuesi Chen
Injectable hydrogels have been widely investigated in biomedical applications, and increasing demand has been proposed to achieve the dynamic regulation of physiological properties of hydrogels. Herein, a new type of injectable and biomolecule-responsive hydrogel based on poly(L-glutamic acid) (PLG) grafted with disulfide bond modified phloretic acid (denoted as PLG-g-CPA) was developed. The hydrogels formed in situ via enzymatic crosslinking under physiological condition in the presence of horseradish peroxidase and hydrogen peroxide...
October 20, 2016: ACS Applied Materials & Interfaces
Yong-Chao Ma, Zhi-Xin Wang, Shao-Ju Jin, Yan-Xin Zhang, Guo-Qiang Hu, Dong-Tao Cui, Jiang-Shuan Wang, Min Wang, Fu-Qing Wang, Zhi-Jun Zhao
Both tyrosine kinase and topoisomerase II (TopII) are important anticancer targets, and their respective inhibitors are widely used in cancer therapy. However, some combinations of anticancer drugs could exhibit mutually antagonistic actions and drug resistance, which further limit their therapeutic efficacy. Here, we report that HMNE3, a novel bis-fluoroquinolone chalcone-like derivative that targets both tyrosine kinase and TopII, induces tumor cell proliferation and growth inhibition. The viabilities of 6 different cancer cell lines treated with a range of HMNE3 doses were detected using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay...
2016: PloS One
Ximena Doldán, Pablo Fagúndez, Alfonso Cayota, Justo Laíz, Juan Pablo Tosar
Extracellular vesicles (EVs), namely exosomes and microvesicles, are important mediators of intercellular communication pathways. Since EVs can be detected in a variety of biofluids and contain a specific set of biomarkers which are reminiscent of their parental cells, they show great promise in clinical diagnostics as EV analysis can be performed in minimally-invasive liquid biopsies. However, reliable, fast and cost-effective methods for their determination are still needed, especially if decentralized analysis is intended...
October 13, 2016: Analytical Chemistry
Manishekhar Kumar, Jeannine M Coburn, David L Kaplan, Biman B Mandal
Macrophages, the key players in immunoregulation, are actively involved in tissue remodelling and vascularization. Recent advances in tissue engineering and regenerative medicine illustrate the importance of 'immuno-informed' biomaterials to regulate the microenvironment of biomedical implants. In the current study, silk-based 3D hydrogels were utilized to regulate cytokine delivery for macrophage, a type of immune cell, differentiation and polarization. Three different hydrogel variants, silk-poly(ethylene glycol) (PEG) (SP), silk-horseradish peroxidase (HRP) (SH) and silk-sonicated (SS) hydrogels were studied...
October 11, 2016: ACS Applied Materials & Interfaces
Xiaohui Geng, Fanglin Zhang, Qiang Gao, Yingfeng Lei
A sensitive and disposable electrochemical impedance biosensor to detect Japanese encephalitis virus (JEV) was developed based on a gold nanoparticle (AuNP)-modified screen-printed carbon electrode (SPCE). A biosensor was fabricated through covalent grafting of a mixed self-assembled monolayer on AuNPs with a specific antibody. To detect JEV and achieve signal amplification, the horseradish peroxidase (HRP)-labeled second antibody was linked to the biosensor through a sandwich immunity reaction. HRP was used to catalyze 4-chloro-1-naphthol oxidation to produce an insoluble precipitate, which introduced a barrier to electron transfer on the electrode...
2016: Analytical Sciences: the International Journal of the Japan Society for Analytical Chemistry
Annewieke J W Verloop, Jean-Paul Vincken, Harry Gruppen
Formation of black tea thearubigins involves at least two of the following oxidation steps: (i) oligomerization, (ii) rearrangement, (iii) hydroxylation. The first two are mainly catalysed by polyphenol oxidase(PPO), whereas the enzyme responsible for hydroxylation has not yet been identified. Two main oxidative activities, peroxidase(POD) and PPO, occur in tea leaves. POD was hypothesized to be responsible for hydroxylation. Model systems with horseradish POD and mushroom tyrosinase were used investigating hydroxylation of theaflavins(TF)...
October 10, 2016: Journal of Agricultural and Food Chemistry
Olusoji A T Afuwape, Catherine R Wasser, Thomas Schikorski, Ege T Kavalali
Earlier studies suggest that spontaneous and evoked neurotransmitter release processes are maintained by synaptic vesicles which are segregated into functionally distinct pools. However, direct interrogation of the link between this putative synaptic vesicle pool heterogeneity and neurotransmission has been difficult. To examine this link, we tagged vesicles with horseradish peroxidase (HRP) - a heme containing plant enzyme - or antibodies against synaptotagmin-1 (syt1). Filling recycling vesicles in hippocampal neurons with HRP and subsequent treatment with hydrogen peroxide (H2 O2 ) modified the properties of neurotransmitter release depending on the route of HRP uptake...
October 10, 2016: Journal of Physiology
Marcin Drozd, Mariusz Pietrzak, Paweł G Parzuchowski, Elżbieta Malinowska
Catalytic nanomaterials, widely used as substitutes of peroxidase, exhibit unique properties, which are unattainable for native enzymes. However, their activity is usually examined by means of substrates developed and methods standardized for horseradish peroxidase (HRP). The aim of the presented work was to determine the scope of usefulness of chromogenic substrates for gold nanoparticle (AuNP) activity studies under conditions which significantly extend beyond the activity range of a native HRP. The applicability of chromogens such as 3,3'5,5'-tetramethylbenzidine (TMB), o-phenylenediamine (OPD), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) beyond the typical range of pH, and for the samples of high concentration of hydrogen peroxide was examined...
October 8, 2016: Analytical and Bioanalytical Chemistry
Muhammad Bilal, Hafiz M N Iqbal, Hongbo Hu, Wei Wang, Xuehong Zhang
In this study, horseradish peroxidase (HRP) was immobilized onto chitosan beads by entrapment method and employed for the degradation of textile dyes. Stable and firm quality chitosan beads developed with 2.5% chitosan concentration exhibited maximum immobilization yield (~92.54±2.53%). The pH optimum of chitosan-immobilized HRP (CTS-HRP) was marginally displaced towards alkaline region (pH7.5) than that of F-HRP which displayed its optimum activity at pH7.0. The free HRP (F-HRP) and CTS-HRP enzyme presented their maximum catalytic activities at 30°C and 70°C, respectively...
October 6, 2016: Science of the Total Environment
Chuanxia Chen, Dan Zhao, Jian Sun, Xiurong Yang
By regulating the catalytic capability of horseradish peroxidase (HRP), an artful colorimetric assay platform for pyrophosphate (PPi) and pyrophosphatase (PPase) was unprecedentedly designed. In this work, Cu(I), generated by reducing Cu(II) in the presence of ascorbate, could inhibit HRP's catalytic capability of transforming colorless 3,3',5,5'-tetramethylbenzidine (TMB) into blue oxidized TMB (oxTMB). The robust coordination between PPi and Cu(II) is able to discourage the reduction of Cu(II) to Cu(I) effectively, thus restoring the original catalytic capability of HRP and regenerating blue-colored oxTMB...
October 7, 2016: ACS Applied Materials & Interfaces
Raghu Ram Achar, B K Venkatesh, H K Vivek, B S Priya, S Nanjunda Swamy
Caralluma umbellata peroxidase (CUP) is an acidic heme-containing protein having a molecular weight of ~42 kDa and is specific to guaiacol. It is not a glycoprotein. It was purified to 12.5-fold purity with 6.16 % yield. Its activity is dependent on hydrogen peroxide and has an optimum pH and temperature of 6.2 and 45 °C respectively. It can decolorize dyes, viz., Aniline Blue, Reactive Black 5, and Reactive Blue 19 but not Congo Red, while HRP can decolorize Congo Red also. It has lignin-degrading potentiality as it can decompose veratryl alcohol...
October 6, 2016: Applied Biochemistry and Biotechnology
Zhixian Li, Yi Ding, Shaomin Li, Yanbin Jiang, Zheng Liu, Jun Ge
A nature-inspired approach to encapsulate enzymes in spindle-like copper hydroxysulfate nanocrystals was developed by a biomimetic mineralization process. Several types of enzymes including glucose oxidase (GOx), horseradish peroxidase (HRP), Candida antarctica lipase B (CALB) and cytochrome c (Cyt c) were successfully encapsulated in copper hydroxysulfate nanocrystals quickly (within 1 hour) with maintained or even greatly enhanced catalytic efficiencies (kcat/KM of Cyt c showed a 143-fold increase) and high stabilities, demonstrating the feasibility of utilizing copper hydroxysulfate nanocrystals as a novel type of nanocarrier for enzyme immobilization...
October 14, 2016: Nanoscale
Justine J Roberts, Pratibha Naudiyal, Khoon S Lim, Laura A Poole-Warren, Penny J Martens
BACKGROUND: Dityrosine crosslinking in proteins is a bioinspired method of forming hydrogels. This study compares oxidative enzyme initiators for their relative crosslinking efficiency and cytocompatibility using the same phenol group and the same material platform. Four common enzyme and enzyme-like oxidative initiators were probed for resulting material properties and cell viability post-encapsulation. RESULTS: All four initiators can be used to form phenol-crosslinked hydrogels, however gelation rates are dependent on enzyme type, concentration, and the oxidant...
2016: Biomaterials Research
Lianhuan Han, Wei Wang, Jacques Nsabimana, Jia-Wei Yan, Bin Ren, Dongping Zhan
Due to a high turnover coefficient, redox enzymes can serve as current amplifiers which make it possible to explore their catalytic mechanism by electrochemistry at the level of single molecules. On modified nanoelectrodes, the voltammetric behavior of a horseradish peroxidase (HRP) catalyzed hydroperoxide reduction no longer presents a continuous current response, but a staircase current response. Furthermore, single catalytic incidents were captured through a collision mode at a constant potential, from which the turnover number of HRP can be figured out statistically...
September 20, 2016: Faraday Discussions
Zhongjing Lu, Christopher R Dockery, Michael Crosby, Katherine Chavarria, Brett Patterson, Matthew Giedd
Escherichia coli O157:H7 and Staphylococcus aureus are two of the major pathogens frequently involved in foodborne outbreaks. Control of these pathogens in foods is essential to food safety. It is of great interest in the use of natural antimicrobial compounds present in edible plants to control foodborne pathogens as consumers prefer more natural "green" foods. Allyl isothiocyanate (AITC) is an antimicrobial compound naturally present in wasabi (Japanese horseradish) and several other edible plants. Although the antibacterial effects of pure AITC and wasabi extract (essential oil) against several bacteria have been reported, the antibacterial property of natural wasabi has not been well studied...
2016: Frontiers in Microbiology
Ramin Fazel, Seyed-Fakhreddin Torabi, Pooya Naseri-Nosar, Salehe Ghasempur, Seyed-Omid Ranaei-Siadat, Khosro Khajeh
Electrospinning, a simple and versatile method to fabricate nanofibrous supports, has attracted attention in the field of enzyme immobilization. Biocomposite nanofibers were fabricated from mixed PVA/BSA solution and the effects of glutaraldehyde treatment, initial BSA concentration and PVA concentration on protein loading were investigated. Glutaraldehyde cross-linking significantly decreased protein release from nanofibers and BSA loading reached as high as 27.3% (w/w). In comparison with the HRP immobilized into the nascent nanofibrous membrane, a significant increase was observed in the activity retention of the enzyme immobilized into the PVA/BSA biocomposite nanofibers...
November 2016: Enzyme and Microbial Technology
Yuqing Yin, Chen Ling Gao, Qi Xiao, Guo Lin, Zian Lin, Zongwei Cai, Huang-Hao Yang
Artificial enzyme mimetics have received considerable attention because natural enzymes have some significant drawbacks, including enzyme autolysis, low catalytic activity, poor recovery and low stability to environmental changes. Herein, we demonstrated a facile approach for one-pot synthesis of hemeprotein-metal organic framework hybrid composites (H-MOFs) by using bovine hemoglobin (BHb) and zeolitic imidazolate framework-8 (ZIF-8) as a model reaction system. Surprisingly, the new hybrid composites exhibits 423% increase in peroxidase-like catalytic activity compared to free BHb...
October 4, 2016: ACS Applied Materials & Interfaces
Ying Wang, Hua Jia, Wen-Yuan Li, Li-Xin Guan, Lingxiao Deng, Yan-Cui Liu, Gui-Bo Liu
The present study aimed to evaluate the molecular mechanisms underlying combinatorial bone marrow stromal cell (BMSC) transplantation and chondroitinase ABC (Ch-ABC) therapy in a model of acellular nerve allograft (ANA) repair of the sciatic nerve gap in rats. Sprague Dawley rats (n=24) were used as nerve donors and Wistar rats (n=48) were randomly divided into the following groups: Group I, Dulbecco's modified Eagle's medium (DMEM) control group (ANA treated with DMEM only); Group II, Ch-ABC group (ANA treated with Ch-ABC only); Group III, BMSC group (ANA seeded with BMSCs only); Group IV, Ch-ABC + BMSCs group (Ch-ABC treated ANA then seeded with BMSCs)...
October 2016: Experimental and Therapeutic Medicine
Ceren Bayraç, Hüseyin Avni Öktem
To monitor the specificity of Staphylococcus aureus aptamer (SA-31) against its target cell, we used enzyme-linked aptamer assay. In the presence of target cell, horseradish peroxidase-conjugated streptavidin bound to biotin-labeled SA-31 showed specific binding to S  aureus among 3 different bacteria with limit of detection of 10(3) colony-forming unit per milliliter. The apparent Ka was 1.39 μM(-1)  ± 0.3 μM(-1) . The binding of SA-31 to membrane proteins extracted from cell surface was characterized using isothermal titration calorimetry, and the effect of changes in binding temperature and salt concentrations of binding buffer was evaluated based on thermodynamic parameters (Ka , ΔH, and ΔG)...
October 3, 2016: Journal of Molecular Recognition: JMR
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