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Diana A Centeno, Xuxan H Solano, John J Castillo
A new plant peroxidase was isolated from the leaves of guinea grass (Panicum maximum) and partially purified using a biphasic polymer system (poly(ethylene glycol) - ammonium sulfate) followed by size-exclusion chromatography and ultracentrifugation until obtaining a homogeneous extract containing a high peroxidase activity. The novel peroxidase was characterized as having a specific activity of 408U/mg and a molecular weight of 30kDa. The pH for its optimum activity was 8.0 and exhibited a high thermostability at 66°C with a kinact of 8...
March 29, 2017: Bioelectrochemistry
Jihane Mandli, Hasna Mohammadi, Aziz Amine
In this work, a novel electrochemical biosensor for miRNA-21 determination, involving a sandwich hybridization assay onto gold nanoparticles modified pencil graphite electrode (PGE) and enzyme signal amplification was reported. The thiol terminated capture probe 1 (SH-P1) was immobilized on the electrode through AuS interaction. In the presence of target miRNA-21, SH-P1 hybridized with the first part of the target, however, the second part hybridizes with a biotinylated probe P2 (B-P2). Then, a streptavidin-conjugated alkaline phosphatase was immobilized by a specific binding of avidin-B-P2...
March 14, 2017: Bioelectrochemistry
Yolina Hubenova, Eleonora Hubenova, Evelina Slavcheva, Mario Mitov
This study provides a new insight into our understanding of yeast response to starvation conditions (sole acetate as carbon source) and applied polarization and offers important information about the role of the glyoxylate cycle in the carbohydrate synthesis and extracellular charge transfer processes in biofuel cells. The biosynthetic capabilities of yeast C. melibiosica 2491 and the up/down-regulation of the glyoxylate cycle are evaluated by modifying the cellular metabolism by feedback inhibition or carbohydrate presence and establishing the malate dehydrogenase activity and carbohydrate content together with the electric charge passed through bioelectrochemical system...
March 14, 2017: Bioelectrochemistry
Mickaël Rimboud, Mohamed Barakat, Alain Bergel, Benjamin Erable
Six biocathodes catalyzing oxygen reduction were designed from the same environmental inoculum but using three different methods. Two were formed freely at open circuit potential, two using conventional aerobic polarization at -0.2V/SCE and two by reversion of already established acetate-fed bioanodes. Observation of the biofilms by SEM and epifluorescence microscopy revealed that reversible bioelectrodes had the densest biofilms. Electrochemical characterization revealed two different redox systems for oxygen reduction, at -0...
March 6, 2017: Bioelectrochemistry
Andrea Hájková, Jiří Barek, Vlastimil Vyskočil
A simple electrochemical DNA biosensor based on a glassy carbon electrode (GCE) was prepared by adsorbing double-stranded DNA (dsDNA) onto the GCE surface and subsequently used for the detection of dsDNA damage induced by hydroxyl radicals. Investigation of the mutual interaction between hydroxyl radicals and dsDNA was conducted using a combination of several electrochemical detection techniques: square-wave voltammetry for direct monitoring the oxidation of dsDNA bases, and cyclic voltammetry and electrochemical impedance spectroscopy as indirect electrochemical methods making use of the redox-active indicator [Fe(CN)6](4-/3-)...
March 1, 2017: Bioelectrochemistry
Na Yang, Yueping Ren, Xiufen Li, Xinhua Wang
Anolyte acidification is a drawback restricting the electricity generation performance of the buffer-free microbial fuel cells (MFC). In this paper, a small amount of alkali-treated anion exchange resin (AER) was placed in front of the anode in the KCl mediated single-chamber MFC to slowly release hydroxyl ions (OH(-)) and neutralize the H(+) ions that are generated by the anodic reaction in two running cycles. This short-term alkaline intervention to the KCl anolyte has promoted the proliferation of electroactive Geobacter sp...
June 2017: Bioelectrochemistry
Reginald M Atkins, Timothy J Fawcett, Richard Gilbert, Andrew M Hoff, Richard Connolly, Douglas W Brown, Anthony J Llewellyn, Mark J Jaroszeski
In vivo gene electro transfer technology has been very successful both in animal models and in clinical trials over the past 20years. However, variable transfection efficiencies can produce inconsistent outcomes. This can be due to differences in tissue architecture and/or chemical composition which may effectively create unique biological environments from subject to subject that may respond differently to the identical electric pulses. This study investigates the integration of impedance spectroscopy into the gene electro transfer process to measure murine skin impedance spectra before, during (after pulse delivery), and after gene electro transfer pulse application to determine if changes in impedance correlate with reporter gene expression...
June 2017: Bioelectrochemistry
P Lamberg, J Hamit-Eminovski, M D Toscano, O Eicher-Lorka, G Niaura, T Arnebrant, S Shleev, T Ruzgas
The interface between protein and material surface is of great research interest in applications varying from implants, tissue engineering to bioelectronics. Maintaining functionality of bioelements depends greatly on the immobilization process. In the present study direct electron transfer of cellobiose dehydrogenase from Humicola insolens (HiCDH), adsorbed on four different self-assembled monolayers (SAMs) formed by 5-6 chain length carbon thiols varying in terminal group structure was investigated. By using a combination of quartz crystal microbalance with dissipation, ellipsometry and electrochemistry the formation and function of the HiCDH film was studied...
June 2017: Bioelectrochemistry
Povilas Simonis, Skirmantas Kersulis, Voitech Stankevich, Vytautas Kaseta, Egle Lastauskiene, Arunas Stirke
Saccharomyces cerevisiae yeast cells were used as a model organism to investigate the effects of various pulsed electric fields on the programed death of such cells. These were exposed to electric field pulses with field strengths (E) of up to 220kV/cm. The effects of square shaped pulses having different durations (τ=10-90ns) and different pulse numbers (pn=1-5) were then analysed. The obtained results show that nanosecond pulses can induce the death of such cells, which in turn is dependent on the electric field pulse parameters and increase with the rise in E, τ and pn...
June 2017: Bioelectrochemistry
G Mohanakrishna, Sai Kishore Butti, R Kannaiah Goud, S Venkata Mohan
A prototype bio-catalyzed electrogenic system integrated with a biological treatment process (SBR-BET) was evaluated to study specific function of anoxic condition on the electrogenic activity. A multiphasic approach was employed, where the influence of DO on bio-electrogenic activity was optimized initially, later optimal anode to cathode inter-electrode distance was enumerated. Amongst the four electrode distances evaluated, 2cm showed higher power output. Bioelectrokinetics analysis was used to validate the system performance with the experimental variation studied...
June 2017: Bioelectrochemistry
I Diaz, J F Martinez-Lerma, R Montoya, I Llorente, M L Escudero, M C García-Alonso
The interaction of the physiological medium and living tissues with the implant surfaces in biological environments is regulated by biopotentials that induce changes in the chemical composition, structure and thickness of the oxide film. In this work, oxide films grown on CoCr alloys at 0.5 V vs Ag/AgCl and 0.7 V vs Ag/AgCl have been characterized through overall and localized electrochemical techniques in a phosphate buffer solution and 0.3% hyaluronic acid. Nanopores of 10-50nm diameter are homogeneously distributed along the surface in the oxide film formed at 0...
June 2017: Bioelectrochemistry
Qi-Xing Ou, Marija Nikolic-Jaric, Michael Gänzle
AIMS: This study aimed to determine how electric field strength, pulse width and shape, and specific energy input relate to the effect of pulsed electric fields (PEF) on viability and membrane permeabilization in Candida humilis and Saccharomyces cerevisiae suspended in potassium phosphate buffer. METHODS AND RESULTS: Cells were treated with a micro-scale system with parallel plate electrodes. Propidium iodide was added before or after treatments to differentiate between reversible and irreversible membrane permeabilization...
June 2017: Bioelectrochemistry
Stephanie A Ventura, Jason Heikenfeld, Tiffany Brooks, Leyla Esfandiari, Steven Boyce, Yoonjee Park, Gerald B Kasting
Continuous monitoring of cortisol at the surface of the skin would advance the diagnosis and treatment of cortisol-related diseases, or of elevated cortisol levels related to stress in otherwise healthy populations. Reliable and accurate detection of cortisol at the skin surface remains a limiting factor in real-time monitoring of cortisol. To address this limitation, cortisol extraction through excised human skin by reverse iontophoresis was studied in vitro in side-by-side diffusion cells using a radiolabeled probe...
April 2017: Bioelectrochemistry
Huiqiang Wang, Hongliang Han, Zhanfang Ma
In this work, a new conductive hydrogel was prepared by a simple cross-linking coordination method using 1,3,5-benzenetricarboxylic acid as the ligand and Fe(3+) as the metal ion. The hydrogel film was formed on a glassy carbon electrode (GCE) by a drop coating method, which can dramatically facilitate the transport of electrons. A sensitive label-free electrochemical immunosensor was fabricated following electrodeposition of gold nanoparticles (AuNPs) on a hydrogel film and immobilization of an antibody. Neuron-specific enolase (NSE), a lung cancer biomarker, was used as the model analyte to be detected...
April 2017: Bioelectrochemistry
Veronika Ostatná, Veronika Kasalová-Vargová, László Kékedy-Nagy, Hana Černocká, Elena E Ferapontova
Specific DNA-protein interactions are vital for cellular life maintenance processes, such as transcriptional regulation, chromosome maintenance, replication and DNA repair, and their monitoring gives valuable information on molecular-level organization of those processes. Here, we propose a new method of label-free electrochemical sensing of sequence specific binding between the lysozyme protein and a single stranded DNA aptamer specific for lysozyme (DNAapta) that exploits the constant current chronopotentiometric stripping (CPS) analysis at modified mercury electrodes...
April 2017: Bioelectrochemistry
Spela Kos, Kevin Vanvarenberg, Tanja Dolinsek, Maja Cemazar, Jure Jelenc, Véronique Préat, Gregor Sersa, Gaëlle Vandermeulen
Skin is an attractive target for gene electrotransfer due to its easy accessibility and its interesting immune properties. Since electrodes are often invasive and frequently induce discomfort during pulse application, there is a fundamental need for non-invasive electrodes for skin delivery. We developed circular pin non-invasive multi-electrode array (MEA), suitable for different clinical applications. MEA was first employed to deliver a luciferase reporter gene. Then, it was used to deliver a DNA vaccine coding for ovalbumin or a plasmid encoding hCAP-18/LL-37 for promoting wound healing...
April 2017: Bioelectrochemistry
Seyyed Mehdi Khoshfetrat, Masoud A Mehrgardi
The increasing demands for early, accurate and ultrasensitive diagnosis of cancers demonstrate the importance of the development of new amplification strategies or diagnostic technologies. In the present study, an aptamer-based electrochemical biosensor for ultrasensitive and selective detection of leukemia cancer cells has been introduced. The thiolated sgc8c aptamer was immobilized on gold nanoparticles-coated magnetic Fe3O4 nanoparticles (Apt-GMNPs). Ethidium bromide (EB), intercalated into the stem of the aptamer hairpin, provides the read-out signal for the quantification of the leukemia cancer cells...
April 2017: Bioelectrochemistry
Teodor Adrian Enache, Ana Maria Oliveira-Brett
The oxidative behaviour of the human amyloid beta (Aβ1-40 and Aβ1-42) peptides and a group of similar peptides: control inverse (Aβ40-1 and Aβ42-1), mutants (Aβ1-40Phe(10) and Aβ1-40Nle(35)), rat Aβ1-40Rat, and fragments (Aβ1-28, Aβ1-16, Aβ10-20, Aβ12-28, and Aβ17-42), in solution or adsorbed, at a glassy carbon electrode, by cyclic and differential pulse voltammetry, were investigated and compared. Structurally the Aβ1-40 and Aβ1-42 sequences contain five electroactive amino acid residues, one tyrosine (Tyr(10)), three histidines (His(6), His(13) and His(14)) and one methionine (Met(35))...
April 2017: Bioelectrochemistry
Masahiro Kaneko, Masahito Ishikawa, Kazuhito Hashimoto, Shuji Nakanishi
For electrochemical regulations of the intracellular metabolisms, lipophilic electron mediators with cell membrane permeability have been conventionally used. We have recently developed amphiphilic, cell-membrane permeable polymer composed of hydrophilic 2-methacryloyloxyethyl phosphorylcholine and hydrophobic redox-active units as a new category of electron mediator. The advantage of the redox active polymer is that we can obtain appropriate molecules in a synthetic bottom-up manner. Here we report that the rate of the extracellular electron transfer (EET) through the redox active polymer can be regulated by sophisticated molecular design of the polymers...
April 2017: Bioelectrochemistry
Jingya Shen, Liping Huang, Peng Zhou, Xie Quan, Gianluca Li Puma
The performance of four indigenous electrochemically active bacteria (EAB) (Stenotrophomonas maltophilia JY1, Citrobacter sp. JY3, Pseudomonas aeruginosa JY5 and Stenotrophomonas sp. JY6) was evaluated for Cu(II) reduction on the cathodes of microbial fuel cells (MFCs). These EAB were isolated from well adapted mixed cultures on the MFC cathodes operated for Cu(II) reduction. The relationship between circuital current, Cu(II) reduction rate, and cellular electron transfer processes was investigated from a mechanistic point of view using X-ray photoelectron spectroscopy, scanning electronic microscopy coupled with energy dispersive X-ray spectrometry, linear sweep voltammetry and cyclic voltammetry...
April 2017: Bioelectrochemistry
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