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Xiao, Xinxin, Hong-qi Xia, Ranran Wu, Lu Bai, Lu Yan, Edmond Magner, Serge Cosnier, Elisabeth Lojou, Zhiguang Zhu e Aihua Liu. "Tackling the Challenges of Enzymatic (Bio)Fuel Cells". Chemical Reviews 119, n.º 16 (25 de junho de 2019): 9509–58. http://dx.doi.org/10.1021/acs.chemrev.9b00115.
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Di Lauro, Michele, Gabriella Buscemi, Michele Bianchi, Anna De Salvo, Marcello Berto, Stefano Carli, Gianluca Maria Farinola, Luciano Fadiga, Fabio Biscarini e Massimo Trotta. "Photovoltage generation in enzymatic bio-hybrid architectures". MRS Advances 5, n.º 18-19 (2020): 985–90. http://dx.doi.org/10.1557/adv.2019.491.
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AbstractMost of the photochemical activity of bacterial photosynthetic apparatuses occurs in the reaction center, a transmembrane protein complex which converts photons into charge-separated states across the membrane with a quantum yield close to unity, fuelling the metabolism of the organism. Integrating the reaction center from the bacterium Rhodobacter sphaeroides onto electroactive surfaces, it is possible to technologically exploit the efficiency of this natural machinery to generate a photovoltage upon Near Infra-Red illumination, which can be used in electronic architectures working in the electrolytic environment such as electrolyte-gated organic transistors and bio-photonic power cells. Here, photovoltage generation in reaction center-based bio-hybrid architectures is investigated by means of chronopotentiometry, isolating the contribution of the functionalisation layers and defining novel surface functionalization strategies for photovoltage tuning.
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Matsena, Mpumelelo Thomas, Shepherd Masimba Tichapondwa e Evans Martin Nkhalambayausi Chirwa. "Synthesis of Biogenic Palladium Nanoparticles Using Citrobacter sp. for Application as Anode Electrocatalyst in a Microbial Fuel Cell". Catalysts 10, n.º 8 (24 de julho de 2020): 838. http://dx.doi.org/10.3390/catal10080838.
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Palladium (Pd) is a cheap and effective electrocatalyst that is capable of replacing platinum (Pt) in various applications. However, the problem in using chemically synthesized Pd nanoparticles (PdNPs) is that they are mostly fabricated using toxic chemicals under severe conditions. In this study, we present a more environmentally-friendly process in fabricating biogenic Pd nanoparticles (Bio-PdNPs) using Citrobacter sp. isolated from wastewater sludge. Successful fabrication of Bio-PdNPs was achieved under anaerobic conditions at pH six and a temperature of 30 °C using sodium formate (HCOONa) as an electron donor. Citrobacter sp. showed biosorption capabilities with no enzymatic contribution to Pd(II) uptake during absence of HCOONa in both live and dead cells. Citrobacter sp. live cells also displayed high enzymatic contribution to the removal of Pd(II) by biological reduction. This was confirmed by Scanning Electron Microscope (SEM), Electron Dispersive Spectroscopy (EDS), and X-ray Diffraction (XRD) characterization, which revealed the presence Bio-PdNPs deposited on the bacterial cells. The bio-PdNPs successfully enhanced the anode performance of the Microbial Fuel Cell (MFC). The MFC with the highest Bio-PdNPs loading (4 mg Bio-PdNP/cm2) achieved a maximum power density of 539.3 mW/m3 (4.01 mW/m2) and peak voltage of 328.4 mV.
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Zhou, Jian, Chang Liu, Hao Yu, Ningli Tang e Chenghong Lei. "Research Progresses and Application of Biofuel Cells Based on Immobilized Enzymes". Applied Sciences 13, n.º 10 (11 de maio de 2023): 5917. http://dx.doi.org/10.3390/app13105917.
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Enzymatic biofuel cells (EBFCs) are devices that use natural enzymes as catalysts to convert chemical energy from bio-sourced fuels into electrical energy. In this review, we summarize recent research progress and applications in the field of biofuel cells based on immobilized enzymes. Specifically, we discuss how to optimize and improve the electrochemical performance and operational stability of enzymatic biofuel cells through enzyme immobilization materials, enzyme immobilization methods, electron transfer improvement on enzyme electrodes, and cell construction methods. We also cover current and future practical applications of biofuel cells based on immobilized enzymes, including implantable enzymatic biofuel cells and wearable enzymatic biofuel cells. Additionally, we present some of the issues that still need to be addressed in the field of biofuel cells based on immobilized enzymes to ensure their technical and commercial viability and sustainability.
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Zhang, Lingling, Isabel Álvarez-Martos, Alexander Vakurov e Elena E. Ferapontova. "Seawater operating bio-photovoltaic cells coupling semiconductor photoanodes and enzymatic biocathodes". Sustainable Energy & Fuels 1, n.º 4 (2017): 842–50. http://dx.doi.org/10.1039/c7se00051k.
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Clean and sustainable production of electricity from sunlight and seawater is possible by H2O/O2 recycling in bio-photovoltaic cells comprising semiconductor photoanodes and an enzymatic biocathode.
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Osman, M. H., A. A. Shah e F. C. Walsh. "Recent progress and continuing challenges in bio-fuel cells. Part I: Enzymatic cells". Biosensors and Bioelectronics 26, n.º 7 (março de 2011): 3087–102. http://dx.doi.org/10.1016/j.bios.2011.01.004.
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Keskinen, Jari, Eino Sivonen, Mikael Bergelin, Jan Erik Eriksson, Pia Sjöberg-Eerola, Matti Valkiainen, Maria Smolander et al. "Printed Supercapacitor as Hybrid Device with an Enzymatic Power Source". Advances in Science and Technology 72 (outubro de 2010): 331–36. http://dx.doi.org/10.4028/www.scientific.net/ast.72.331.
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Low cost printable power sources are needed e.g. in sensors and RFID applications. As manufacturing method printing techniques are preferred in order to keep the costs low. The materials should also be easily disposable. Enzymatic bio-fuel cells are an alternative for printable primary batteries. Since one drawback of bio-fuel cells is their low power, we have developed supercapacitors that can be combined with enzymatic bio-fuel cells to provide the power peaks necessary in the applications. The materials for the supercapacitors have been chosen to be compatible with the fuel cell and with printing methods, e.g. the activated carbon powder in the electrodes was bound with chitosan. As printing substrates we have used paperboards. The current collectors have been made of graphite and metal inks. Since the voltage requirement is limited to approximately 1 V, aqueous electrolytes have been used. Printed supercapacitors of various sizes have been prepared. The geometrical electrode areas have been between 0.5 and 2 cm2. The maximum feasible output current has been in the order of 50 mA corresponding to about 50 mW power. When the capacitor is used together with an enzymatic power source, the leakage current must be as low as possible. Typical leakage current values have been in the order of 10 µA.
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Lee, Su Jeong, Jun Hee Lee, Jisun Park, Wan Doo Kim e Su A. Park. "Fabrication of 3D Printing Scaffold with Porcine Skin Decellularized Bio-Ink for Soft Tissue Engineering". Materials 13, n.º 16 (10 de agosto de 2020): 3522. http://dx.doi.org/10.3390/ma13163522.
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Recently, many research groups have investigated three-dimensional (3D) bioprinting techniques for tissue engineering and regenerative medicine. The bio-ink used in 3D bioprinting is typically a combination of synthetic and natural materials. In this study, we prepared bio-ink containing porcine skin powder (PSP) to determine rheological properties, biocompatibility, and extracellular matrix (ECM) formation in cells in PSP-ink after 3D printing. PSP was extracted without cells by mechanical, enzymatic, and chemical treatments of porcine dermis tissue. Our developed PSP-containing bio-ink showed enhanced printability and biocompatibility. To identify whether the bio-ink was printable, the viscosity of bio-ink and alginate hydrogel was analyzed with different concentration of PSP. As the PSP concentration increased, viscosity also increased. To assess the biocompatibility of the PSP-containing bio-ink, cells mixed with bio-ink printed structures were measured using a live/dead assay and WST-1 assay. Nearly no dead cells were observed in the structure containing 10 mg/mL PSP-ink, indicating that the amounts of PSP-ink used were nontoxic. In conclusion, the proposed skin dermis decellularized bio-ink is a candidate for 3D bioprinting.
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Le Goff, Alan, e Michael Holzinger. "Molecular engineering of the bio/nano-interface for enzymatic electrocatalysis in fuel cells". Sustainable Energy & Fuels 2, n.º 12 (2018): 2555–66. http://dx.doi.org/10.1039/c8se00374b.
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The fascinating topic of converting chemical energy into electric power using biological catalysts, called enzymes, and sustainable fuels motivates a large community of scientists to develop enzymatic fuel cells.
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Shimoda, Kei, Manabu Hamada, Masaharu Seno, Tadakatsu Mandai e Hiroki Hamada. "Chemo-Enzymatic Synthesis of Glycolyl-Ester-Linked Taxol-Monosaccharide Conjugate and Its Drug Delivery System Using Hepatitis B Virus Envelope L Bio-Nanocapsules". Biochemistry Insights 5 (janeiro de 2012): BCI.S9824. http://dx.doi.org/10.4137/bci.s9824.
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Chemo-enzymatic synthesis of glycolyl-ester-linked taxol-glucose conjugate, ie, 7-glycolyltaxol 2′- O-α-D-glucoside, was achieved by using α-glucosidase as a biocatalyst. The water-solubility of 7-glycolyltaxol 2′- O-α-D-glucoside (21 μM) was 53 fold higher than that of taxol. The hepatitis B virus envelope L particles (bio-nanocapsules) are effective for delivering 7-glycolyltaxol 2′- O-α-D-glucoside to human hepatocellular carcinoma NuE cells.
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Ortega-Santos, Amaia Beatriz, Yaxin Qiu, Jose Gabriel Martinez e Edwin W. H. Jager. "Enzymatic Biofuel Cells Embedded Polymer-Based Soft Actuators". ECS Meeting Abstracts MA2022-02, n.º 54 (9 de outubro de 2022): 2035. http://dx.doi.org/10.1149/ma2022-02542035mtgabs.
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Enzymatic biofuel cells are presented as an untethered alternative energy source that could power small implantable or wearable medical devices. However, most of these catalytic processes do not provide with enough energy to power common small electronic-mechanical devices. On the other hand, conducting polymer-based actuators are of great interest for their biocompatibility, flexibility, processability, possibility to be miniaturized and low power consumption. So far, these artificial muscles have been driven by external power sources that prevent them for being completely autonomous. There is a need for a novel power source to elaborate actuators that could use physiological processes as a driving force. These soft actuators’ low power consumption matches the electrical power generated by the biocatalysis of some enzymes, such as glucose oxidase and laccase in presence of glucose and oxygen in aqueous media. Here, we present the latest results in the development of polypyrrole-based soft actuators powered by enzymatic biofuel cells. The actuator consists of a tri-layer conductive substrate on which the polypyrrole is electrodeposited in both sides. The polypyrrole layers act as the active part, expanding and contracting upon a redox reaction, resulting in a bending movement. Tetrathiofulvlene-7,7,8,8-tetracyanoquinodimethane (TTF-TCNQ) and 2,2′-azino-di-(3-ethylbenzthiazoline sulfonic acid) (ABTS) electron transfer mediators are cast on the surface of the polypyrrole to help the electron transmission. The glucose oxidase and laccase enzymes are immobilized in the modified-conducting polymer surface, integrating the electrode to the actuator. The bio-catalysis of enzymes in presence of glucose and oxygen in aqueous solution provides the actuator with the electrons needed for the redox reaction, converting the chemical energy into mechanical energy, i.e., movement. The glucose-self-powered soft actuator may contribute to the development of more complex implantable, ingestible, or wearable biomedical devices such as cardio-stimulators, insulin pumps, or muscle implants.
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Liu, Xinyu, Meron Tsegay Kifle, Hongxin Xie, Liexi Xu, Maoling Luo, Yangyi Li, Zhengrong Huang, Yan Gong, Yuzhou Wu e Conghua Xie. "Biomineralized Manganese Oxide Nanoparticles Synergistically Relieve Tumor Hypoxia and Activate Immune Response with Radiotherapy in Non-Small Cell Lung Cancer". Nanomaterials 12, n.º 18 (10 de setembro de 2022): 3138. http://dx.doi.org/10.3390/nano12183138.
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Radiotherapy (RT) is currently considered as an essential treatment for non-small cell lung cancer (NSCLC); it can induce cell death directly and indirectly via promoting systemic immune responses. However, there still exist obstacles that affect the efficacy of RT such as tumor hypoxia and immunosuppressive tumor microenvironment (TME). Herein, we report that the biomineralized manganese oxide nanoparticles (Bio-MnO2 NPs) prepared by mild enzymatic reaction could be a promising candidate to synergistically enhance RT and RT-induced immune responses by relieving tumor hypoxia and activating cGAS-STING pathway. Bio-MnO2 NPs could convert endogenic H2O2 to O2 and catalyze the generation of reactive oxygen species so as to sensitize the radiosensitivity of NSCLC cells. Meanwhile, the release of Mn2+ into the TME significantly enhanced the cGAS-STING activity to activate radio-immune responses, boosting immunogenic cell death and increasing cytotoxic T cell infiltration. Collectively, this work presents the great promise of TME reversal with Bio-MnO2 NPs to collaborate RT-induced antitumor immune responses in NSCLC.
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Matsumoto, Takahiro, Idol Phann e Naoko Okibe. "Biogenic Platinum Nanoparticles’ Production by Extremely Acidophilic Fe(III)-Reducing Bacteria". Minerals 11, n.º 11 (22 de outubro de 2021): 1175. http://dx.doi.org/10.3390/min11111175.
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Platinum nanoparticles (Pt(0)NPs) are expected to play a vital role in future technologies as high-performance catalysts. The microbiological route for Pt(0)NPs’ production is considered a greener and simpler alternative to conventional methods. In order to explore the potential utility of extreme acidophiles, Fe(III)-reducing acidophilic bacteria, Acidocella aromatica and Acidiphilium crytpum, were tested for the production of bio-Pt(0)NPs from an acidic solution. Bio-Pt(0)NPs were successfully formed via a simple one-step reaction with the difference in the size and location between the two strains. Intact enzymatic activity was essential to exhibit the site for Pt(0) crystal nucleation, which enables the formation of well-dispersed, fine bio-Pt(0)NPs. Active Ac. aromatica cells produced the finest bio-Pt(0)NPs of mean and median size of 16.1 and 8.5 nm, respectively. The catalytic activity of bio-Pt(0)NPs was assessed using the Cr(VI) reduction reaction, which was shown to be in a negative linear correlation with the mean particle size under the conditions tested. This is the first study reporting the recruitment of acidophilic extremophiles for the production of Pt(0)NPs. Acidophilic extremophiles often inhabit metal-rich acidic liquors in nature and are expected to become the promising tool for metal nanotechnology.
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Iñiguez-Moreno, Maricarmen, Melesio Gutiérrez-Lomelí e María Guadalupe Avila-Novoa. "Removal of Mixed-Species Biofilms Developed on Food Contact Surfaces with a Mixture of Enzymes and Chemical Agents". Antibiotics 10, n.º 8 (30 de julho de 2021): 931. http://dx.doi.org/10.3390/antibiotics10080931.
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Sanicip Bio Control (SBC) is a novel product developed in Mexico for biofilms’ removal. The aims of this study were to evaluate (i) the removal of mixed-species biofilms by enzymatic (protease and α-amylase, 180 MWU/g) and chemical treatments (30 mL/L SBC, and 200 mg/L peracetic acid, PAA) and (ii) their effectiveness against planktonic cells. Mixed-species biofilms were developed on stainless steel (SS) and polypropylene B (PP) in whole milk (WM), tryptic soy broth (TSB) with meat extract (TSB+ME), and TSB with chicken egg yolk (TSB+EY) to simulate the food processing environment. On SS, all biofilms were removed after treatments, except the enzymatic treatment that only reduced 1–2 log10 CFU/cm2, whereas on PP, the reductions ranged between 0.59 and 5.21 log10 CFU/cm2, being the biofilms developed in TSB+EY being resistant to the cleaning and disinfecting process. Higher reductions in microbial load on PP were reached using enzymes, SBC, and PAA. The employed planktonic cells were markedly more sensitive to PAA and SBC than were the sessile cells. In conclusion, biofilm removal from SS can be achieved with SBC, enzymes, or PAA. It is important to note that the biofilm removal was strongly affected by the food contact surfaces (FCSs) and surrounding media.
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Arab, Bahareh, Adam Westbrook, Murray Moo-Young, Yilan Liu e C. Perry Chou. "High-Level Bio-Based Production of Coproporphyrin in Escherichia coli". Fermentation 10, n.º 5 (11 de maio de 2024): 250. http://dx.doi.org/10.3390/fermentation10050250.
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This study reports on the development of effective strain engineering strategies for the high-level bio-based production of coproporphyrin (CP), a porphyrin pigment compound with various applications, using Escherichia coli as a production host. Our approach involves heterologous implementation of the Shemin/C4 pathway in an E. coli host strain with an enlarged intracellular pool of succinyl-CoA. To regulate the expression of the key pathway genes, including hemA/B/D/E/Y, we employed a plasmid system comprising two operons regulated by strong trc and gracmax promoters, respectively. Using the engineered E. coli strains for bioreactor cultivation under aerobic conditions with glycerol as the carbon source, we produced up to 353 mg/L CP with minimal byproduct formation. The overproduced CP was secreted extracellularly, posing minimal physiological toxicity and impact on the producing cells. To date, targeted bio-based production of CP by E. coli has yet to be reported. In addition to the demonstration of high-level bio-based production of CP, our study underscores the importance of identifying key enzymatic reactions limiting the overall metabolite production for developing differential expression strategies for pathway modulation and even optimization. This investigation paves the way for the development of effective metabolic engineering strategies based on targeted manipulation of key enzymes to customize engineered strains for effective large-scale bio-based production.
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Agee, Alec, e Ariel L. Furst. "Bio-Inspired Polymer Design for Enhanced Microbial Electrocatalysis". ECS Meeting Abstracts MA2023-01, n.º 42 (28 de agosto de 2023): 2356. http://dx.doi.org/10.1149/ma2023-01422356mtgabs.
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Microbial electrocatalysis is an emerging technology which enables electricity generation directly from organic feedstocks, many of which are otherwise difficult to harness for renewable energy. While microbes possess unique advantages for these applications, their use in practical settings is currently limited by inefficient electron transfer from cells to electrodes. To address this bottleneck, we have developed improved electrode materials that combine principles of conductive polymer design with lessons from enzymatic electron transfer reactions. Our polymer electrodes exhibit superior nanoscale electroactive area and enable concerted two-electron transfer from the electron carrier flavin mononucleotide (FMN) to an abiotic surface, a high efficiency mechanism which was previously restricted to biological contexts. Electroactive microbes exhibited greatly improved current production on polymer electrodes in quantitative agreement with in vitro electrochemical properties. Our findings establish bio-inspired functionalization as a useful paradigm to bridge the gap between microbial metabolism and abiotic electrochemistry.
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A. Karim, Nabila, e Hsiharng Yang. "Mini-Review: Recent Technologies of Electrode and System in the Enzymatic Biofuel Cell (EBFC)". Applied Sciences 11, n.º 11 (3 de junho de 2021): 5197. http://dx.doi.org/10.3390/app11115197.
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Enzymatic biofuel cells (EBFCs) is one of the branches of fuel cells that can provide high potential for various applications. However, EBFC has challenges in improving the performance power output. Exploring electrode materials is one way to increase enzyme utilization and lead to a high conversion rate so that efficient enzyme loading on the electrode surface can function correctly. This paper briefly presents recent technologies developed to improve bio-catalytic properties, biocompatibility, biodegradability, implantability, and mechanical flexibility in EBFCs. Among the combinations of materials that can be studied and are interesting because of their properties, there are various nanoparticles, carbon-based materials, and conductive polymers; all three have the advantages of chemical stability and enhanced electron transfer. The methods to immobilize enzymes, and support and substrate issues are also covered in this paper. In addition, the EBFC system is also explored and developed as suitable for applications such as self-pumping and microfluidic EBFC.
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He, Long, Ting He, Shabnam Farrar, Linbao Ji, Tianyi Liu e Xi Ma. "Antioxidants Maintain Cellular Redox Homeostasis by Elimination of Reactive Oxygen Species". Cellular Physiology and Biochemistry 44, n.º 2 (2017): 532–53. http://dx.doi.org/10.1159/000485089.
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Reactive oxygen species (ROS) are produced by living cells as normal cellular metabolic byproduct. Under excessive stress conditions, cells will produce numerous ROS, and the living organisms eventually evolve series of response mechanisms to adapt to the ROS exposure as well as utilize it as the signaling molecules. ROS molecules would trigger oxidative stress in a feedback mechanism involving many biological processes, such as apoptosis, necrosis and autophagy. Growing evidences have suggested that ROS play a critical role as the signaling molecules throughout the entire cell death pathway. Overwhelming production of ROS can destroy organelles structure and bio-molecules, which lead to inflammatory response that is a known underpinning mechanism for the development of diabetes and cancer. Cytochrome P450 enzymes (CYP) are regarded as the markers of oxidative stress, can transform toxic metabolites into ROS, such as superoxide anion, hydrogen peroxide and hydroxyl radical which might cause injury of cells. Accordingly, cells have evolved a balanced system to neutralize the extra ROS, namely antioxidant systems that consist of enzymatic antioxidants such as superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidases (GPxs), thioredoxin (Trx) as well as the non-enzymatic antioxidants which collectively reduce oxidative state. Herein, we review the recent novel findings of cellular processes induced by ROS, and summarize the roles of cellular endogenous antioxidant systems as well as natural anti-oxidative compounds in several human diseases caused by ROS in order to illustrate the vital role of antioxidants in prevention against oxidative stress.
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Echeverri, Danilo, Juliana Romo, Néstor Giraldo e Lucía Atehortúa. "Microalgae protoplasts isolation and fusion for biotechnology research". Revista Colombiana de Biotecnología 21, n.º 1 (1 de janeiro de 2019): 101–12. http://dx.doi.org/10.15446/rev.colomb.biote.v21n1.80248.
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Protoplasts are microbial or vegetable cells lacking a cell wall. These can be obtained from microalgae by an enzymatic hydrolysis process in the presence of an osmotic stabilizer. In general, protoplasts are experimentally useful in physiological, geneticand bio-chemical studies, so their acquisition and fusion will continue to be an active research area in modern biotechnology. The fusion of protoplasts in microalgae constitutes a tool for strain improvement because it allows both intra and interspecific genetic recombina-tion, resulting in organisms with new or improved characteristics of industrial interest. In this review we briefly describe themethod-ology for obtaining protoplasts, as well as fusion methods and the main applications of microalgal platforms.
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Bai, Xuefei, Wenhui Liu, Shijie Jin, Wenbin Zhao, Yingchun Xu, Zhan Zhou, Shuqing Chen e Liqiang Pan. "Facile Generation of Potent Bispecific Fab via Sortase A and Click Chemistry for Cancer Immunotherapy". Cancers 13, n.º 18 (10 de setembro de 2021): 4540. http://dx.doi.org/10.3390/cancers13184540.
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Bispecific antibodies (BsAbs) for T cell engagement have shown great promise in cancer immunotherapy, and their clinical applications have been proven in treating hematological malignance. Bispecific antibody binding fragment (BiFab) represents a promising platform for generating non-Fc bispecific antibodies. However, the generation of BiFab is still challenging, especially by means of chemical conjugation. More conjugation strategies, e.g., enzymatic conjugation and modular BiFab preparation, are needed to improve the robustness and flexibility of BiFab preparation. We successfully used chemo-enzymatic conjugation approach to generate bispecific antibody (i.e., BiFab) with Fabs from full-length antibodies. Paired click handles (e.g., N3 and DBCO) was introduced to the C-terminal LPETG tag of Fabs via sortase A mediated transpeptidation, followed by site-specific conjugation between two click handle-modified Fabs for BiFab generation. Both BiFabCD20/CD3 (EC50 = 0.26 ng/mL) and BiFabHer2/CD3 exhibited superior efficacy in mediating T cells, from either PBMC or ATC, to kill target tumor cell lines while spared antigen-negative tumor cells in vitro. The BiFabCD20/CD3 also efficiently inhibited CD20-positive tumor growth in mouse xenograft model. We have established a facile sortase A-mediated click handle installation to generate homogeneous and functional BiFabs. The exemplary BiFabs against different targets showed superior efficacy in redirecting and activating T cells to specifically kill target tumor cells, demonstrating the robustness of sortase A-mediated “bio-click” chemistry in generating various potent BiFabs. This approach also holds promise for further efficient construction of a Fab derivative library for personalized tumor immunotherapy in the future.
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Jun, Chang-Duk, Jeong-Su Park, Jun-Hyeong Kim, Won-Chang Soh, Na-Young Kim, Kyung-Sik Lee, Chang-Hyun Kim, Ik-Joo Chung, Sunjae Lee e Hye-Ran Kim. "Trogocytic-molting of T-cell microvilli controls T-cell clonal expansion". Journal of Immunology 210, n.º 1_Supplement (1 de maio de 2023): 168.01. http://dx.doi.org/10.4049/jimmunol.210.supp.168.01.
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Abstract Internalization of the T-cell antigen receptor (TCR) is intimately linked to T-cell activation: a phenomenon thought to be related to the “exhaustion” of T-cell responses. To date, however, no report has considered that during physical interaction with cognate antigen-presenting cells, T cells release many TCRs via T-cell microvilli particles, which are derived from finger-like membrane structures (microvilli) in a combined process of trogocytosis and enzymatic vesiculation and correspond with the loss of membrane TCRs and many external membrane components. Surprisingly, in contrast to TCR internalization, this event leads to rapid upregulation of surface TCRs and remarkable metabolic reprogramming of cholesterol and fatty acids synthesis to meet the demands of clonal expansion, which drives multiple rounds of division and cell survival. We called this event “trogocytic-molting,” which represents an intrinsic molecular basis of T-cell clonal expansion by which T cells gain increased sensitivity to low antigen concentrations. This work was supported by the Creative Research Initiative Program (2015R1A3A2066253); Bio-Synergy Research Project (2021M3A9C4000991); Bio & Medical Technology Development Program [2020M3A9G3080281] through National Research Foundation (NRF) grants funded by the Ministry of Science and ICT (MSIT), the Basic Science Program (2019R1C1C1009570 & 2022R1A2C4002627) through National Research Foundation (NRF) grants funded by the Ministry of Education (MOE), and supported by Global University Project (GUP), GIST Research Institute (GRI) IBBR grant funded by the GIST (in 2021-2022), and the Joint Research Project of Institutes of Science and Technology (2021–2022), Korea.
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Jofré, Ignacio, Francisco Matus, Daniela Mendoza, Francisco Nájera e Carolina Merino. "Manganese-Oxidizing Antarctic Bacteria (Mn-Oxb) Release Reactive Oxygen Species (ROS) as Secondary Mn(II) Oxidation Mechanisms to Avoid Toxicity". Biology 10, n.º 10 (6 de outubro de 2021): 1004. http://dx.doi.org/10.3390/biology10101004.
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Manganese (Mn) oxidation is performed through oxidative Mn-oxidizing bacteria (MnOxb) as the main bio-weathering mechanism for Mn(III/IV) deposits during soil formation. However, with an increase in temperature, the respiration rate also increases, producing Reactive Oxygen Species (ROS) as by-products, which are harmful to microbial cells. We hypothesize that bacterial ROS oxidize Mn(II) to Mn(III/IV) as a secondary non-enzymatic temperature-dependent mechanism for cell protection. Fourteen MnOxb were isolated from Antarctic soils under the global warming effect, and peroxidase (PO) activity, ROS, and Mn(III/IV) production were evaluated for 120 h of incubation at 4 °C, 15 °C, and 30 °C. ROS contributions to Mn oxidation were evaluated in Arthrobacter oxydans under antioxidant (Trolox) and ROS-stimulated (menadione) conditions. The Mn(III/IV) concentration increased with temperature and positively correlated with ROS production. ROS scavenging with Trolox depleted the Mn oxidation, and ROS-stimulant increased the Mn precipitation in A. oxydans. Increasing the Mn(II) concentration caused a reduction in the membrane potential and bacterial viability, which resulted in Mn precipitation on the bacteria surface. In conclusion, bacterial ROS production serves as a complementary non-enzymatic temperature-dependent mechanism for Mn(II) oxidation as a response in warming environments.
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Koller, Martin. "Polyhydroxyalkanoate Biosynthesis at the Edge of Water Activity-Haloarchaea as Biopolyester Factories". Bioengineering 6, n.º 2 (16 de abril de 2019): 34. http://dx.doi.org/10.3390/bioengineering6020034.
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Haloarchaea, the extremely halophilic branch of the Archaea domain, encompass a steadily increasing number of genera and associated species which accumulate polyhydroxyalkanoate biopolyesters in their cytoplasm. Such ancient organisms, which thrive in highly challenging, often hostile habitats characterized by salinities between 100 and 300 g/L NaCl, have the potential to outperform established polyhydroxyalkanoate production strains. As detailed in the review, this optimization presents due to multifarious reasons, including: cultivation setups at extreme salinities can be performed at minimized sterility precautions by excluding the growth of microbial contaminants; the high inner-osmotic pressure in haloarchaea cells facilitates the recovery of intracellular biopolyester granules by cell disintegration in hypo-osmotic media; many haloarchaea utilize carbon-rich waste streams as main substrates for growth and polyhydroxyalkanoate biosynthesis, which allows coupling polyhydroxyalkanoate production with bio-economic waste management; finally, in many cases, haloarchaea are reported to produce copolyesters from structurally unrelated inexpensive substrates, and polyhydroxyalkanoate biosynthesis often occurs in parallel to the production of additional marketable bio-products like pigments or polysaccharides. This review summarizes the current knowledge about polyhydroxyalkanoate production by diverse haloarchaea; this covers the detection of new haloarchaea producing polyhydroxyalkanoates, understanding the genetic and enzymatic particularities of such organisms, kinetic aspects, material characterization, upscaling and techno-economic and life cycle assessment.
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Escarrat, Vincent, Jimena Perez-Sanchez, Bilal El-Waly, Jorge E. Collazos-Castro e Franck Debarbieux. "Composite Fibrin and Carbon Microfibre Implant to Modulate Postraumatic Inflammation after Spinal Cord Injury". Cells 12, n.º 6 (8 de março de 2023): 839. http://dx.doi.org/10.3390/cells12060839.
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Poor functional recovery after spinal cord injury (SCI) drives the development of novel strategies to manage this devastating condition. We recently showed promising immunomodulatory and pro-regenerative actions of bio-functionalized carbon microfibres (MFs) implanted in a rodent model of SCI. In order to maximize tissue repair while easing MF implantation, we produced a composite implant based on the embedding of several MFs within a fibrin hydrogel. We used intravital imaging of fluorescent reporter mice at the early stages and spinal sections of the same animals 3 months later to characterize the neuroinflammatory response to the implant and its impact on axonal regeneration. Whereas fibrin alone was inert in the first week, its enzymatic degradation drove the chronic activation of microglial cells and axonal degeneration within 3 months. However, the presence of MFs inside the fibrin hydrogel slowed down fibrin degradation and boosted the early recruitment of immune cells. Noteworthy, there was an enhanced contribution of monocyte-derived dendritic cells (moDCs), preceding a faster transition toward an anti-inflammatory environment with increased axonal regeneration over 3 months. The inclusion of MF here ensured the long-term biocompatibility of fibrin hydrogels, which would otherwise preclude successful spinal cord regeneration.
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Mosneagu, A. M., e I. Stolerii. "VALIDITY OF THE QUASI STEADY STATE ASSUMPTION FOR ENZYME-CATALYSED REACTIONS WITH COMPETITIVE INHIBITION AND SUBSTRATE INPUT". Annals of the Academy of Romanian Scientists Series on Mathematics and Its Application 15, n.º 1-2 (2023): 383–407. http://dx.doi.org/10.56082/annalsarscimath.2023.1-2.383.
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Enzyme-catalysed reactions are chemical reactions within cells in which the rate of the reaction is significantly increased through the action of enzymes. They are usually part of large and complex bio¬chemical networks, which form the central processing units of the living cell. Enzymatic reactions often operate on multiple time scales, which can be characterized as being either fast or slow. The quasi steady¬state approximation (QSSA) utilizes time scale separation to pro ject these complex models onto lower-dimensional slow manifolds. In this paper, we investigate the validity of a quasi steady-state assumption for enzyme-catalysed biochemical reactions with competitive inhibition that are subject to a constant substrate input. Necessary and sufficient conditions for the validity of these assumptions were derived and were shown to be dependent, among others, on the substrate input. The validity conditions are numerically verified using the classical Runge- Kutta method.
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Ghorbel, Mouna, Ikram Zribi, Malek Besbes, Nouha Bouali e Faiçal Brini. "Catalase Gene Family in Durum Wheat: Genome-Wide Analysis and Expression Profiling in Response to Multiple Abiotic Stress Conditions". Plants 12, n.º 14 (21 de julho de 2023): 2720. http://dx.doi.org/10.3390/plants12142720.
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Catalase (CAT) is an antioxidant enzyme expressed by the CAT gene family and exists in almost all aerobic organisms. In fact, the CAT enzyme modulates the hydrogen peroxide (H2O2) contents in cells by translating this toxic compound into water (H2O) and O2− to reduce reactive oxygen species (ROS) contents in cells. ROS are produced as a result of biotic and abiotic environmental stressors. To avoid ROS toxicity, plants are armed with different enzymatic and non-enzymatic systems to decompose ROS. Among the enzymatic system, CAT proteins are well studied. CAT not only controls growth and development in plants but is also involved in plant defense against different stresses. So far, the CAT gene family has not been reported in durum wheat (Triticum turgidum ssp. durum L.). Therefore, a genome-wide comprehensive analysis was conducted to classify the CAT genes in the durum wheat genome. Here, six TdCAT genes were identified. Based on phylogenetics, the TdCAT genes belong to three groups (Groups I–III) which is explainable by their comparable structural characteristics. Using bio-informatic analysis, we found that the secondary and tertiary structures were conserved among plants and present similar structures among durum wheat CATs. Two conserved domains (pfam00199 and pfam06628) are also present in all identified proteins, which have different subcellular localizations: peroxisome and mitochondrion. By analyzing their promoters, different cis-elements were identified, such as hormone-correlated response and stress-related responsive elements. Finally, we studied the expression pattern of two catalase genes belonging to two different sub-classes under different abiotic stresses. Expression profiling revealed that TdCAT2 and TdCAT3 presented a constitutive expression pattern. Moreover, both genes are induced in response to salt, mannitol, cold, heat and ABA. Thus, we speculate that those genes are activated by different stresses, such as oxygen deficiency, light, cold, abscisic acid and methyl jasmonate. Further, this study will help in understanding the behavior of CAT genes during environmental stress in durum wheat and in Triticeae species in general.
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Dai, Lin, Zhina Lian, Yixiu Fu, Xin Zhou, Yong Xu, Xuelian Zhou, Boris N. Kuznetsov e Kankan Jiang. "Low pH Stress Enhances Gluconic Acid Accumulation with Enzymatic Hydrolysate as Feedstock Using Gluconobacter oxydans". Fermentation 9, n.º 3 (12 de março de 2023): 278. http://dx.doi.org/10.3390/fermentation9030278.
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Gluconic acid has been increasingly in demand in recent years due to the wide applications in the food, healthcare and construction industries. Plant-derived biomass is rich in biopolymers that comprise glucose as the monomeric unit, which provide abundant feedstock for gluconic acid production. Gluconobacter oxydans can rapidly and incompletely oxidize glucose to gluconic acid and it is regarded as ideal industrial microorganism. Once glucose is depleted, the gluconic acid will be further bio-oxidized to 2-ketogluconic acid by Gluconobacter oxydans. The endpoint is difficult to be controlled, especially in an industrial fermentation process. In this study, it was found that the low pH environment (2.5~3.5) could limit the further metabolism of gluconic acid and that it resulted in a yield over 95%. Therefore, the low pH stress strategy for efficiently producing gluconic acid from biomass-derived glucose was put forward and investigated with enzymatic hydrolysate. As a result, 98.8 g/L gluconic acid with a yield of 96% could be obtained from concentrated corncob enzymatic hydrolysate that initially contained 100 g/L glucose with 1.4 g/L cells loading of Gluconobacter oxydans. In addition, the low pH stress strategy could effectively control end-point and decrease the risk of microbial contamination. Overall, this strategy provides a potential for industrial gluconic acid production from lignocellulosic materials.
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Zerva, Anastasia, Stefan Simić, Evangelos Topakas e Jasmina Nikodinovic-Runic. "Applications of Microbial Laccases: Patent Review of the Past Decade (2009–2019)". Catalysts 9, n.º 12 (4 de dezembro de 2019): 1023. http://dx.doi.org/10.3390/catal9121023.
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There is a high number of well characterized, commercially available laccases with different redox potentials and low substrate specificity, which in turn makes them attractive for a vast array of biotechnological applications. Laccases operate as batteries, storing electrons from individual substrate oxidation reactions to reduce molecular oxygen, releasing water as the only by-product. Due to society’s increasing environmental awareness and the global intensification of bio-based economies, the biotechnological industry is also expanding. Enzymes such as laccases are seen as a better alternative for use in the wood, paper, textile, and food industries, and they are being applied as biocatalysts, biosensors, and biofuel cells. Almost 140 years from the first description of laccase, industrial implementations of these enzymes still remain scarce in comparison to their potential, which is mostly due to high production costs and the limited control of the enzymatic reaction side product(s). This review summarizes the laccase applications in the last decade, focusing on the published patents during this period.
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Khan, Yunus Y., e Vasanti Suvarna. "LIPOSOMES CONTAINING PHYTOCHEMICALS FOR CANCER TREATMENT-AN UPDATE". International Journal of Current Pharmaceutical Research 9, n.º 1 (31 de dezembro de 2016): 20. http://dx.doi.org/10.22159/ijcpr.2017v9i1.16629.
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Many phytochemicals exhibit promising effects in treatment and prevention of various cancers, but due to their poor water solubility, stability, bio-availability and target specificity make administering them at therapeutic doses impractical. This is especially true for curcumin, quercetin, resveratrol and berberine. There is rising activity in developing nano drug delivery systems for these phytochemicals. These nano drug delivery systems mainly include liposomes, micelles, solid lipid nanoparticles, nanoemulsions, which are biocompatible and biodegradable nanoparticles. These nanoparticles can increase the stability and aqueous solubility of phytochemicals. They can also be used as sustained drug delivery systems. Much work has also proven that they enhance the absorption and bioavailability of the phytochemicals, protect them from premature enzymatic degradation or metabolism, hence prolonging their circulation time. Besides these parameters, in this review, we have also mentioned the improved target specificity of phytochemicals to cancer cells or tumours via passive or targeted delivery. Hence, nanotechnology cleared the way for developing phytochemical-loaded nanoparticles for prevention and treatment of cancer.
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Bayer, Thomas, Aileen Becker, Henrik Terholsen, In Jung Kim, Ina Menyes, Saskia Buchwald, Kathleen Balke, Suvi Santala, Steven C. Almo e Uwe T. Bornscheuer. "LuxAB-Based Microbial Cell Factories for the Sensing, Manufacturing and Transformation of Industrial Aldehydes". Catalysts 11, n.º 8 (10 de agosto de 2021): 953. http://dx.doi.org/10.3390/catal11080953.
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The application of genetically encoded biosensors enables the detection of small molecules in living cells and has facilitated the characterization of enzymes, their directed evolution and the engineering of (natural) metabolic pathways. In this work, the LuxAB biosensor system from Photorhabdus luminescens was implemented in Escherichia coli to monitor the enzymatic production of aldehydes from primary alcohols and carboxylic acid substrates. A simple high-throughput assay utilized the bacterial luciferase—previously reported to only accept aliphatic long-chain aldehydes—to detect structurally diverse aldehydes, including aromatic and monoterpene aldehydes. LuxAB was used to screen the substrate scopes of three prokaryotic oxidoreductases: an alcohol dehydrogenase (Pseudomonas putida), a choline oxidase variant (Arthrobacter chlorophenolicus) and a carboxylic acid reductase (Mycobacterium marinum). Consequently, high-value aldehydes such as cinnamaldehyde, citral and citronellal could be produced in vivo in up to 80% yield. Furthermore, the dual role of LuxAB as sensor and monooxygenase, emitting bioluminescence through the oxidation of aldehydes to the corresponding carboxylates, promises implementation in artificial enzyme cascades for the synthesis of carboxylic acids. These findings advance the bio-based detection, preparation and transformation of industrially important aldehydes in living cells.
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Hamada, Hiroki, Kei Shimoda e Masaharu Seno. "Chemo-enzymatic Synthesis of Propionyl-ester-linked Taxol-monosaccharide Conjugate and its Drug Delivery System Using Hybrid-Bio-nanocapsules Targeting Brain Glioma Cells". Clinical Medicine Insights: Women's Health 6 (janeiro de 2013): CMWH.S8213. http://dx.doi.org/10.4137/cmwh.s8213.
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Iwanaga, Shintaroh, Yuta Hamada, Yoshinari Tsukamoto, Kenichi Arai, Taketoshi Kurooka, Shinji Sakai e Makoto Nakamura. "Design and Fabrication of Mature Engineered Pre-Cardiac Tissue Utilizing 3D Bioprinting Technology and Enzymatically Crosslinking Hydrogel". Materials 15, n.º 22 (9 de novembro de 2022): 7928. http://dx.doi.org/10.3390/ma15227928.
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The fabrication of mature engineered cardiac tissue is one of the major challenges in cardiac tissue engineering. For this purpose, we attempted to apply the 3D bioprinting approach. Aiming to construct an oriented tissue, a fine fiber-shaped scaffold with a support structure was first designed using CAD software. Then, a 3D bioprinter and cell-adhesive bio-inks were utilized to fabricate this structure. The cell-adhesive bio-inks were synthesized by combining sodium alginate and gelatin with tyramine, respectively, to form pre-gel materials that allow enzymatic crosslinking by horseradish peroxidase. By absorbance measurements, we confirmed that the tyramine modification rate of each polymer was 0.535 mmol/g-alginate and 0.219 mmol/g-gelatin. The width of the fiber-shaped scaffold was 216.8 ± 24.3 μm for the fabricated scaffold, while the design value was 200 μm. After 3D printing and adhesion-adding treatment of the scaffold with these bio-ink materials, cardiomyocytes were seeded and cultured. As a result, the cells spread onto the scaffold, and the entire pre-tissue contracted synchronously by day 6 of culture, showing a greater pulsatility than in the early days. Video analysis showed that the beating rate of pre-myocardial tissue on day 6 was 31 beats/min. In addition, we confirmed that the cardiomyocytes partially elongated along the long axis of the fiber-shaped scaffold in the pre-tissue cultured for 15 days by staining actin, suggesting the possibility of cell orientation. Furthermore, treatment with adrenaline resulted in a 7.7-fold increase in peak beating rate compared to that before treatment (from 6 beats/min to 46 beats/min), confirming the responsiveness of the pre-tissues to the drug. These results indicate that 3D bioprinting effectively produces mature cultured myocardial tissue that is oriented, contracts synchronously, and is responsive to drugs.
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Fontana, Mario, Aysenur Gunaydin Akyildiz, Chiara D’Alonzo, Fabio Giovannercole, Arianna Zicchi, Antonio Francioso, Elisabetta Capuozzo e Daniela De Biase. "Synthesis and Biological Activity of Homohypotaurine Obtained by the Enzyme-Based Conversion of Homocysteine Sulfinic Acid Using Recombinant Escherichia Coli Glutamate Decarboxylase". Molecules 29, n.º 17 (23 de agosto de 2024): 3985. http://dx.doi.org/10.3390/molecules29173985.
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l-Homocysteine, formed from S-adenosyl methionine following demethylation and adenosine release, accumulates when the methionine recycling pathway and other pathways become impaired, thus leading to hyperhomocysteinemia, a biomarker in cardiovascular diseases, neurological/psychiatric disorders, and cancer. The partial oxidation of the l-homocysteine thiol group and its decarboxylation on C-alpha lead to the formation of l-homocysteinesulfinic acid (l-HCSA) and homohypotaurine (HHT), respectively. Both compounds are not readily available from commercial suppliers, which hinders the investigation of their biological activities. Herein, the chemical synthesis of l-HCSA, from l-homocystine, was the starting point for establishing the bio-based synthesis of HHT using recombinant Escherichia coli glutamate decarboxylase (EcGadB), an enzyme already successfully employed for the bio-based synthesis of GABA and its phosphinic analog. Prior to HHT synthesis, kcat (33.92 ± 1.07) and KM (38.24 ± 3.45 mM) kinetic constants were determined for l-HCSA on EcGadB. The results of our study show that the EcGadB-mediated synthesis of HHT can be achieved with good yields (i.e., 40% following enzymatic synthesis and column chromatography). Purified HHT was tested in vitro on primary human umbilical vein endothelial cells and rat cardiomyoblasts and compared to the fully oxidized analog, homotaurine (OT, also known as tramiprosate), in widespread pharmaceutical use. The results show that both cell lines display statistically significant recovery from the cytotoxic effects induced by H2O2 in the presence of HHT.
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Ruthenbeck, Alexandra, Elisa Marangoni, Björn-Ph Diercks, Aileen Krüger, Alexander Froese, Nadja Bork, Viacheslav Nikolaev, Andreas Guse e Chris Meier. "Membrane-Permeable Octanoyloxybenzyl-Masked cNMPs As Novel Tools for Non-Invasive Cell Assays". Molecules 23, n.º 11 (13 de novembro de 2018): 2960. http://dx.doi.org/10.3390/molecules23112960.
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Adenine nucleotide (AN) 2nd messengers, such as 3′,5′-cyclic adenosine monophosphate (cAMP), are central elements of intracellular signaling, but many details of their underlying processes remain elusive. Like all nucleotides, cyclic nucleotide monophosphates (cNMPs) are net-negatively charged at physiologic pH which limits their applicability in cell-based settings. Thus, many cellular assays rely on sophisticated techniques like microinjection or electroporation. This setup is not feasible for medium- to high-throughput formats, and the mechanic stress that cells are exposed to raises the probability of interfering artefacts or false-positives. Here, we present a short and flexible chemical route yielding membrane-permeable, bio-reversibly masked cNMPs for which we employed the octanoyloxybenzyl (OB) group. We further show hydrolysis studies on chemical stability and enzymatic activation, and present results of real-time assays, where we used cAMP and Ca2+ live cell imaging to demonstrate high permeability and prompt intracellular conversion of some selected masked cNMPs. Based on these results, our novel OB-masked cNMPs constitute valuable precursor-tools for non-invasive studies on intracellular signaling.
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Prasad, Rajesh Kumar. "The Implementation of Waste Biomass Substrates as Feedstock for The Production of Bio-Electricity Through Microbial Fuel Cells (MFCS): A Short Review". International Journal of Biomass and Renewables 12, n.º 2 (31 de outubro de 2023): 13. http://dx.doi.org/10.61762/ijbrvol12iss2art24517.
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Lignocellulosic biomass plays a pivotal role in sustainable energy production, with a focus on indirect biomass fuel cells (IDBFC) and direct biomass fuel cells (DBFC). IDBFCs require the initial conversion of biomass into simpler forms like sugars, biogas, syngas, or biocharfor subsequent electricity generation. In contrast, DBFCs offer a more direct approach, generating electricity from biomass without intermediate steps. Lignocellulosic biomass, composed of cellulose, lignin, and hemicellulose, has diverse applications, from bioethanolto direct electricity generation. However, the complex composition of lignocellulosic compounds, including carbon, hydrogen, oxygen, phosphorus, nitrogen, and sulfur, poses challenges for efficient enzymatic hydrolysis, a crucial factor in achieving high power density inMicrobial Fuel Cells (MFCs). MFCs use microorganisms to convert substrates into electricity, influenced by factors like substrate degradation rate, circuit resistance, electron transfer rates, proton mass transfer, electrode materials, and operational conditions. The selection of proper electrode materials is vital for optimising MFC performance. At the heart of MFC performance are electricigens, microorganisms facilitating electron transfer from biomass to the anode through direct or indirect mechanisms. Direct electron transfer (DET), relying on physical contact between microorganism membranes and the anode, is preferred for its efficiency and eco-friendliness. The paper also explores the importance of nutrient supplements (macro and micro) in enhancing bio-methane production and process stability in agro-industrial biogas mono-digestion plants. Nutrient balance significantly affects microbial generation time, degradation rates, and gas production in anaerobic digestion processes. In conclusion, understanding the intricate interplay between lignocellulosic biomass energy fuel cells, electricigens, and their performance factors is crucial for advancing sustainable energy production. MFCs show promise in utilising sludge and various waste biomasses, positioning them as practical, reliable, and versatile power sources in the evolving landscape of renewable energy technologies.
Keywords: Lignocellulosic waste, bioenergy, microbial fuel cells (MFCs), electricigens
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Martins, Luis M., Timothy J. Kottke, Scott H. Kaufmann e William C. Earnshaw. "Phosphorylated Forms of Activated Caspases Are Present in Cytosol From HL-60 Cells During Etoposide-Induced Apoptosis". Blood 92, n.º 9 (1 de novembro de 1998): 3042–49. http://dx.doi.org/10.1182/blood.v92.9.3042.
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Abstract Treatment of HL-60 human leukemia cells with etoposide induces apoptotic cell death and activation of at least 18 electrophoretically distinct cysteine-dependent aspartate-directed protease (caspase) isoforms, several of which differ only in their isoelectric points. The purpose of the present study was to determine whether activated caspases are phosphorylated. Phosphatase treatment of cytosolic extracts containing active caspases followed by affinity labeling with N-(N-benzyloxycarbonylglutamyl-N-biotinyllysyl)aspartic acid [(2,6-dimethylbenzoyl)oxy] methyl ketone (Z-EK(bio)D-aomk) showed a mobility shift in several of the labeled species, suggesting that phosphorylated forms of these enzymes are present in the extracts. Metabolic labeling with 32P followed by etoposide treatment and subsequent affinity purification of affinity-labeled caspases confirmed that at least three caspase species were phosphorylated. To detect effects of the phosphorylation on enzymatic activity, caspase-mediated cleavage of aspartylglutamylvalinylaspartyl-7-amino-4-trifluoromethylcoumarin (DEVD-AFC) and poly(ADP-ribose) polymerase (PARP) by phosphorylated and dephosphorylated extracts was measured. No significant changes in Km or vmax were detected using DEVD-AFC. In contrast, a slight, but significant enhancement of PARP cleavage was observed in dephosphorylated extracts, suggesting that phosphorylation of active caspases could have an inhibitory effect on enzyme activity. These observations, which provide the first evidence that caspases are phosphoproteins, suggest that caspases may be targets for some of the growing list of protein kinases that are involved in apoptotic events. © 1998 by The American Society of Hematology.
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Martins, Luis M., Timothy J. Kottke, Scott H. Kaufmann e William C. Earnshaw. "Phosphorylated Forms of Activated Caspases Are Present in Cytosol From HL-60 Cells During Etoposide-Induced Apoptosis". Blood 92, n.º 9 (1 de novembro de 1998): 3042–49. http://dx.doi.org/10.1182/blood.v92.9.3042.421k55_3042_3049.
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Treatment of HL-60 human leukemia cells with etoposide induces apoptotic cell death and activation of at least 18 electrophoretically distinct cysteine-dependent aspartate-directed protease (caspase) isoforms, several of which differ only in their isoelectric points. The purpose of the present study was to determine whether activated caspases are phosphorylated. Phosphatase treatment of cytosolic extracts containing active caspases followed by affinity labeling with N-(N-benzyloxycarbonylglutamyl-N-biotinyllysyl)aspartic acid [(2,6-dimethylbenzoyl)oxy] methyl ketone (Z-EK(bio)D-aomk) showed a mobility shift in several of the labeled species, suggesting that phosphorylated forms of these enzymes are present in the extracts. Metabolic labeling with 32P followed by etoposide treatment and subsequent affinity purification of affinity-labeled caspases confirmed that at least three caspase species were phosphorylated. To detect effects of the phosphorylation on enzymatic activity, caspase-mediated cleavage of aspartylglutamylvalinylaspartyl-7-amino-4-trifluoromethylcoumarin (DEVD-AFC) and poly(ADP-ribose) polymerase (PARP) by phosphorylated and dephosphorylated extracts was measured. No significant changes in Km or vmax were detected using DEVD-AFC. In contrast, a slight, but significant enhancement of PARP cleavage was observed in dephosphorylated extracts, suggesting that phosphorylation of active caspases could have an inhibitory effect on enzyme activity. These observations, which provide the first evidence that caspases are phosphoproteins, suggest that caspases may be targets for some of the growing list of protein kinases that are involved in apoptotic events. © 1998 by The American Society of Hematology.
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Barbon, Silvia, Andrea Biccari, Elena Stocco, Giovanni Capovilla, Edoardo D’Angelo, Martina Todesco, Deborah Sandrin et al. "Bio-Engineered Scaffolds Derived from Decellularized Human Esophagus for Functional Organ Reconstruction". Cells 11, n.º 19 (20 de setembro de 2022): 2945. http://dx.doi.org/10.3390/cells11192945.
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Esophageal reconstruction through bio-engineered allografts that highly resemble the peculiar properties of the tissue extracellular matrix (ECM) is a prospective strategy to overcome the limitations of current surgical approaches. In this work, human esophagus was decellularized for the first time in the literature by comparing three detergent-enzymatic protocols. After decellularization, residual DNA quantification and histological analyses showed that all protocols efficiently removed cells, DNA (<50 ng/mg of tissue) and muscle fibers, preserving collagen/elastin components. The glycosaminoglycan fraction was maintained (70–98%) in the decellularized versus native tissues, while immunohistochemistry showed unchanged expression of specific ECM markers (collagen IV, laminin). The proteomic signature of acellular esophagi corroborated the retention of structural collagens, basement membrane and matrix–cell interaction proteins. Conversely, decellularization led to the loss of HLA-DR expression, producing non-immunogenic allografts. According to hydroxyproline quantification, matrix collagen was preserved (2–6 µg/mg of tissue) after decellularization, while Second-Harmonic Generation imaging highlighted a decrease in collagen intensity. Based on uniaxial tensile tests, decellularization affected tissue stiffness, but sample integrity/manipulability was still maintained. Finally, the cytotoxicity test revealed that no harmful remnants/contaminants were present on acellular esophageal matrices, suggesting allograft biosafety. Despite the different outcomes showed by the three decellularization methods (regarding, for example, tissue manipulability, DNA removal, and glycosaminoglycans/hydroxyproline contents) the ultimate validation should be provided by future repopulation tests and in vivo orthotopic implant of esophageal scaffolds.
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Urabe, Mamoru, Takara Yamamoto, Jo Kitawaki, Hideo Honjo e Hiroji Okada. "Estrogen biosynthesis in human uterine adenomyosis". Acta Endocrinologica 121, n.º 2 (agosto de 1989): 259–64. http://dx.doi.org/10.1530/acta.0.1210259.
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Abstract. Estrogen biosynthesis (aromatase activity) was investigated in human adenomyosis tissue and compared with that of the normal myometrium, endometrium, and endometrial cancer tissues. Homogenates were incubated with [1,2,6,7-3H]androstenedione and NADPH at 37° C for 1 h. After stopping the enzymatic reaction with ethyl acetate, [4-14C]estrone and [4-14C]estradiol-17β were added to the incubated sample. Estrone and estradiol were purified and identified by Bio-Rad AG1-X2 column chromatography, thin-layer chromatography and co-crystallization. Estrogen formed in the incubated sample was calculated from the 3H/14C ratio of the final crystal. The value for estrone formed from androstenedione was 52–132 fmol· h −1 · g−1 wet weight. Aromatase activity in the adenomyosis tissues was higher than that in normal endometrial or myometrial tissues, but lower than that found in myometrial or endometrial tumour tissue. Furthermore, we investigated the effect of danazol, progesterone, and medroxyprogesterone acetate on adenomyosis cells in primary cultures. Aromatase activity in adenomyosis was blocked by danazol, but stimulated by progesterone and MPA. These results indicate that aromatase activity in adenomyosis may contribute to the growth of the ectopic endometrial tissue which occurs in this disease.
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Lungu, Claudiu N., Melinda E. Füstös, Ireneusz P. Grudziński, Gabriel Olteanu e Mihai V. Putz. "Protein Interaction with Dendrimer Monolayers: Energy and Surface Topology". Symmetry 12, n.º 4 (17 de abril de 2020): 641. http://dx.doi.org/10.3390/sym12040641.
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Protein interaction with polymers layers is a keystone in designing bio-nano devices. Polyamidoamines (PAMAMs) are well-known polymers. Zero aromatic core dendrimers (ZAC) are molecules with no proven toxic effect in cultured cells. When coating nanodevices with enzymatic systems, active sites are disturbed by an interaction with the biosystem surface. Computational methods were used in order to simulate, characterize, and quantify protein–polymer interaction. Protein corona, i.e., surface proteins disposed on a viral membrane or nanodevice outer surface, are crucial in interactions with a potential pharmacological target or receptor. Corona symmetry has been observed in the Middle East respiratory syndrome-related coronavirus (MERS-CoV), severe acute respiratory syndrome coronavirus (SARS-CoV), and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). As a protein alpha 1 antitrypsin’s a crystallographic structure was chosen. Protein–mono dendrimer layer systems were generated using in silico methods in order to simulate their interaction. Interactions were quantified using topological and quantum mechanical strategies. Results showed that PAMAM and ZAC interact differently with alpha 1 antitrypsin. Energy and topological surfaces of protein vary accordingly with the dendrimer monolayer. Topological surfaces have a higher sensibility in describing the interactions.
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Giang, Huynh-Nguyet-Huong, Feng-Pai Chou, Ching-Yun Chen, Shen-Chieh Chou, Sheng-Cih Huang, Tuoh Wu, Bui-Thi-Buu Hue, Hong-Cheu Lin e Tung-Kung Wu. "Quinazolinone-Peptido-Nitrophenyl-Derivatives as Potential Inhibitors of SARS-CoV-2 Main Protease". Viruses 15, n.º 2 (19 de janeiro de 2023): 287. http://dx.doi.org/10.3390/v15020287.
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The severe acute respiratory syndrome coronavirus 2 main protease (SARS-CoV-2-Mpro) plays an essential role in viral replication, transcription, maturation, and entry into host cells. Furthermore, its cleavage specificity for viruses, but not humans, makes it a promising drug target for the treatment of coronavirus disease 2019 (COVID-19). In this study, a fragment-based strategy including potential antiviral quinazolinone moiety and glutamine- or glutamate-derived peptidomimetic backbone and positioned nitro functional groups was used to synthesize putative Mpro inhibitors. Two compounds, G1 and G4, exhibited anti-Mpro enzymatic activity in a dose-dependent manner, with the calculated IC50 values of 22.47 ± 8.93 μM and 24.04 ± 0.67 μM, respectively. The bio-layer interferometer measured real-time binding. The dissociation kinetics of G1/Mpro and G4/Mpro also showed similar equilibrium dissociation constants (KD) of 2.60 × 10−5 M and 2.55 × 10−5 M, respectively, but exhibited distinct association/dissociation curves. Molecular docking of the two compounds revealed a similar binding cavity to the well-known Mpro inhibitor GC376, supporting a structure−function relationship. These findings may open a new avenue for developing new scaffolds for Mpro inhibition and advance anti-coronavirus drug research.
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Pacini, Lorenzo, Annunziata D’Ercole, Anna Maria Papini, Daniele Bani, Silvia Nistri e Paolo Rovero. "Porcine Relaxin but Not Serelaxin Shows Residual Bioactivity after In Vitro Simulated Intestinal Digestion—Clues for the Development of New Relaxin Peptide Agonists Suitable for Oral Delivery". International Journal of Molecular Sciences 24, n.º 1 (20 de dezembro de 2022): 48. http://dx.doi.org/10.3390/ijms24010048.
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Despite human recombinant H2 relaxin or serelaxin holding promise as a cardiovascular drug, its actual efficacy in chronic treatment of heart failure patients was hampered by the need to be administered by multiple daily IV injections for a long time, with obvious drawbacks in terms of patients’ compliance. This in vitro study aimed at exploring the molecular background for a possible administration of the peptide hormone relaxin by the oral route. Serelaxin and purified porcine relaxin (pRLX) were subjected to simulated intestinal fluid (SIF) enzymatic digestion in vitro to mimic the behavior of gastroprotective formulations. The digestion time course was studied by HPLC, and the relative bio-potency of the intact molecules and their proteolytic fragments was assessed by second messenger (cAMP) response in RXFP1 relaxin receptor-bearing THP-1 human monocytic cells. Both intact proteins (100 ng/mL) induced a significant cAMP rise in THP-1 cells. Conversely, SIF-treated serelaxin showed a brisk (30 s) bioactivity decay, dropping down to the levels of the unstimulated controls at 120 s, whereas SIF-treated pRLX retained significant bioactivity for up to 120 s. After that, it progressively declined to the levels of the unstimulated controls. HPLC analysis indicates that this bioactivity could be ascribed to a minor component of the pRLX sample more resistant to proteolysis. When identified and better characterized, this peptide could be exploited for the development of synthetic relaxin agonists suitable for oral formulations.
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Demkiv, Olha, Galina Gayda, Nataliya Stasyuk, Anna Moroz, Roman Serkiz, Asta Kausaite-Minkstimiene, Mykhailo Gonchar e Marina Nisnevitch. "Flavocytochrome b2-Mediated Electroactive Nanoparticles for Developing Amperometric L-Lactate Biosensors". Biosensors 13, n.º 6 (28 de maio de 2023): 587. http://dx.doi.org/10.3390/bios13060587.
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L-Lactate is an indicator of food quality, so its monitoring is essential. Enzymes of L-Lactate metabolism are promising tools for this aim. We describe here some highly sensitive biosensors for L-Lactate determination which were developed using flavocytochrome b2 (Fcb2) as a bio-recognition element, and electroactive nanoparticles (NPs) for enzyme immobilization. The enzyme was isolated from cells of the thermotolerant yeast Ogataea polymorpha. The possibility of direct electron transfer from the reduced form of Fcb2 to graphite electrodes has been confirmed, and the amplification of the electrochemical communication between the immobilized Fcb2 and the electrode surface was demonstrated to be achieved using redox nanomediators, both bound and freely diffusing. The fabricated biosensors exhibited high sensitivity (up to 1436 A·M−1·m−2), fast responses, and low limits of detection. One of the most effective biosensors, which contained co-immobilized Fcb2 and the hexacyanoferrate of gold, having a sensitivity of 253 A·M−1·m−2 without freely diffusing redox mediators, was used for L-Lactate analysis in samples of yogurts. A high correlation was observed between the values of analyte content determined using the biosensor and referenced enzymatic-chemical photometric methods. The developed biosensors based on Fcb2-mediated electroactive nanoparticles can be promising for applications in laboratories of food control.
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Pandove, G., P. Sahota e N. Gupta. "Development of low alcoholic naturally carbonated fermented debittered beverage from grapefruit (Citrus paradisi)". Journal of Applied and Natural Science 8, n.º 3 (1 de setembro de 2016): 1649–53. http://dx.doi.org/10.31018/jans.v8i3.1017.
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A pure yeast Clavispora lusitaniae, isolated from whey beverage, phenotypically characterized and molecularly characterized by sequencing of D1/D2 domain of 26S rRNA and Internal Transcribed Spacer (ITS) region was used to produce low alcoholic naturally carbonated fermented debittered beverage from Grapefruit. C. lusitaniae produces enzyme naringinase. This enzyme is a mixture of α-L-rhamnosidase and β-D-glucosidase. The bitter component in citrus fruit, naringin can be hydrolyzed by α-L-rhamnosidase to rhamnose and prunin then by β-glucosidase to glucose and naringenin. The freshly prepared fermented Grapefruit beverage had TSS 14 °B, pH 4.7, acidity 0.26%, brix acid ratio 53.85, total sugars 11.6%, reducing sugars 3.34%, ascorbic acid 21.9 mg/100 ml, naringin 643.2 ppm, alcohol 0.00% (v/v), CO2 0.00 bar and total yeast count 5.83 (Log no.of cells/ml). Physico-chemical changes recorded after three months of storage at refrigerated temperature revealed TSS 12.0 °B, pH 4.2, acidity 0.54%, brix acid ratio 22.22, total sugars 8.97%, reducing sugars 1.94%, ascorbic acid 18.45 mg/100 ml, naringin 365.2 ppm, alcohol 0.76 % (v/v), CO2 1.35 bar and total yeast count 8.54 (Log no.of cells/ml). Naturally produced CO2 by C. lusitaniae during fermentation adds effervescence, sparkle, tangy taste to the beverage in addition to its antimicrobial properties. Thus bio-enzymatic debittering by C. lusitaniae may become the new direction of citrus juice processing in the future, due to its economical viability with strong ability to remove the bitter taste from citrus juice beverage.
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Cowan, Andrew J., Margot Pont, Blythe Duke Sather, Cameron J. Turtle, Brian G. Till, Edward Libby, David G. Coffey et al. "Safety and Efficacy of Fully Human BCMA CAR T Cells in Combination with a Gamma Secretase Inhibitor to Increase BCMA Surface Expression in Patients with Relapsed or Refractory Multiple Myeloma". Blood 138, Supplement 1 (5 de novembro de 2021): 551. http://dx.doi.org/10.1182/blood-2021-154170.
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Abstract Background: Chimeric antigen receptor T cells (CAR T cells) targeting B cell maturation antigen (BCMA) have demonstrated rapid and deep responses among patients with multi-agent refractory multiple myeloma (MM). BCMA is shed from tumor cells mediated through enzymatic cleavage by the gamma secretase complex, and tumor cells with low levels of BCMA could potentially escape CAR T recognition. We showed previously that gamma secretase inhibitors (GSI) increase BCMA surface density on tumor cells, decrease soluble BCMA levels, and enhance efficacy of BCMA CAR T cells in an immunodeficient mouse model. We have completed accrual to a phase 1 first-in-human trial of escalating doses of BCMA targeted CAR T cells in combination with a GSI (JSMD194) for patients with relapsed or refractory multiple myeloma, and herein report results on the 18 patients accrued to this trial. Methods: Eligible patients had relapsed/refractory MM, with ≥ 10% plasma cells in the bone marrow by CD138 IHC, and measurable disease. CD8+ and CD4+ T cells were enriched by To assess the discrete impact of the GSI on plasma cell BCMA expression, patients received a GSI (JSMD194) monotherapy "run-in" consisting of three oral doses (25 mg) administered 48 hours apart over 5 days. A bone marrow sample was obtained on day 5 and BCMA expression was compared to baseline. Following lymphodepleting chemotherapy, BCMA CAR T cells were infused at a starting dose of 5 x 10 7 CAR+ cells, in combination with JSMD194 dosed orally at 25 mg thrice weekly for three weeks, starting on the day of CAR infusion. Results: From June 2018 to March 2021, 18 patients underwent leukapheresis, run-in with JSMD194, and treatment with BCMA CAR T cells. The median age was 65 years, and patients had received a median of 10 prior lines of therapy (range, 4-19). 67% of patients were refractory to lenalidomide, pomalidomide, bortezomib, carfilzomib, and daratumumab, 72% had high-risk cytogenetic features, and 28% had extramedullary disease. 7/18 (39%) had prior BCMA targeted therapy; other BCMA targeted CAR T cell products had previously been administered to 4/18 patients (22%). All 18 treated patients completed the 5-day run-in with JSMD194. After three oral doses of GSI, increased from a median of 610 to 9563 receptors per cell, or a median of 12-fold (range, 0.2-fold to 157-fold; Figure 1). The only patient that did not demonstrate an increase in BCMA ABC after GSI run-in had previously received BCMA targeted therapy and BCMA expression at screening was virtually absent. 5 patients were treated at 5x10 7 CAR+ cells, 3 were treated at 15x10 7 CAR+ cells, 3 were treated at 30x10 7 CAR+ cells, and 7 were treated at 45x10 7 CAR+ cells dose levels. Treatment was consistent with other BCMA CAR T therapy, with manageable toxicities. One patient experienced a DLT. 95% of patients experienced cytokine release syndrome (CRS), mostly grade 1-2 (83%), and 66% of patients experienced ICANS, predominantly grades 1-2. The overall response rate was 89%, with 14 patients achieving ≥ VGPR, and 8 patients achieving CR (including 5 with sCR). Deep responses were observed at all dose levels; including the first patient treated on trial at (dose level 1) who has maintained a stringent CR (sCR) for over 35 months and 3 of 5 patients at dose level 1 had no evidence of progressive disease for >18 months. With a median follow-up of 20 months, the median PFS is 11 months (95% CI, 6 mos to not reached). Amongst patients without prior exposure to BCMA targeted therapy (n=11), the median PFS has not been reached, while amongst those previously exposed to BCMA targeted therapy (n=7), the median PFS was 2 months. Discussion: In this study combining a GSI with BCMA CAR T cells, we have demonstrated that the combination is safe and tolerable. GSI administration routinely increased BCMA surface density on plasma cells. Further, we have observed durable, rapid responses in a heavily pretreated refractory population of MM patients, of whom a significant proportion had prior treatment with BCMA targeted therapy and CAR T therapy. The combination of BCMA CAR T and GSI may augment anti-tumor activity, even when very low doses of BCMA CAR T cells are administered. Figure 1 Figure 1. Disclosures Cowan: Harpoon: Research Funding; Secura Bio: Consultancy; Sanofi Aventis: Consultancy, Research Funding; GSK: Consultancy; Abbvie: Consultancy, Research Funding; Nektar: Research Funding; Cellectar: Consultancy; Bristol Myers Squibb: Research Funding; Janssen: Consultancy, Research Funding. Pont: Lyell Immunopharma: Other: Has equity interest; SpringWorks Therapeutics: Other: Received consulting income; CellPoint B.V.: Current Employment. Sather: Lyell Immunopharma: Current Employment. Turtle: Arsenal Bio: Current holder of stock options in a privately-held company, Other: Scientific Advisory Board; PACT Pharma: Consultancy; Amgen: Consultancy; Eureka Therapeutics: Current holder of stock options in a privately-held company, Other: Scientific Advisory Board; AstraZeneca: Consultancy, Research Funding; Juno Therapeutics/BMS: Patents & Royalties: Right to receive royalties from Fred Hutch for patents licensed to Juno Therapeutics, Research Funding; Myeloid Therapeutics: Current holder of stock options in a privately-held company, Other: Scientific Advisory Board; TCR2 Therapeutics: Research Funding; T-CURX: Other: Scientific Advisory Board; Asher Bio: Consultancy; Allogene: Consultancy; Century Therapeutics: Consultancy, Other: Scientific Advisory Board; Nektar Therapeutics: Consultancy, Research Funding; Precision Biosciences: Current holder of stock options in a privately-held company, Other: Scientific Advisory Board; Caribou Biosciences: Consultancy, Current holder of stock options in a privately-held company, Other: Scientific Advisory Board. Till: Mustang Bio: Consultancy, Patents & Royalties, Research Funding. Libby: GSK: Research Funding; Janssen: Consultancy, Research Funding; BMS: Research Funding; Genentech: Research Funding. Tuazon: BMS: Current Employment. Shadman: Abbvie, Genentech, AstraZeneca, Sound Biologics, Pharmacyclics, Beigene, Bristol Myers Squibb, Morphosys, TG Therapeutics, Innate Pharma, Kite Pharma, Adaptive Biotechnologies, Epizyme, Eli Lilly, Adaptimmune , Mustang Bio and Atara Biotherapeutics: Consultancy; Mustang Bio, Celgene, Bristol Myers Squibb, Pharmacyclics, Gilead, Genentech, Abbvie, TG Therapeutics, Beigene, AstraZeneca, Sunesis, Atara Biotherapeutics, GenMab: Research Funding. Chapuis: Karkinos Therapeutics: Other: Ownership; Lonza: Other: Intellectual Property; Cullian: Other: Intellectual Property; TScan Therapeutics, Inc.: Consultancy, Other: Ownership; SignalOne Bio: Consultancy, Other: Ownership; Bluebird bio: Other: Intellectual Property; Juno therapeutics: Other: Intellectual Property; Adapyive Biotechnologies Corporation: Other: Ownership/Intellectual Property; Pfizer: Other: Intellectual Property; Affini-T: Other: Ownership; Ridgeline: Consultancy; BioNTech: Consultancy. Maloney: MorphoSys: Honoraria; Genentech: Honoraria; Navan Technologies: Honoraria, Other: Stock options; Celgene: Honoraria, Other: Rights to royalties from Fred Hutchinson Cancer Research Center for patents licensed to Juno Therapeutics/Bristol Myers Squibb; Novartis: Honoraria; Kite Pharma: Honoraria, Other: Research funding was paid to my institution, Research Funding; Juno therapeutics: Other: Research funding was paid to my institution, Research Funding; Celgene: Other: Research funding was paid to my institution, Research Funding; Amgen: Honoraria; BMS: Honoraria, Other: Rights to royalties from Fred Hutchinson Cancer Research Center for patents licensed to Juno Therapeutics/Bristol Myers Squibb; Juno Therapeutics: Honoraria, Other: Rights to royalties from Fred Hutchinson Cancer Research Center for patents licensed to Juno Therapeutics/Bristol Myers Squibb; Umoja: Honoraria; Legend Biotech: Honoraria; A2 Biotherapeutics: Honoraria, Other: Stock options; Janssen: Honoraria. Riddell: Lyell Immunopharma: Other. Green: Seagen Inc.: Research Funding; bristol myers squibb: Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding; Cellectar Biosciences: Research Funding; GSK: Membership on an entity's Board of Directors or advisory committees; Janssen Biotech: Membership on an entity's Board of Directors or advisory committees, Research Funding; Juno Therapeutics: Patents & Royalties, Research Funding; Legend Biotech: Consultancy; Neoleukin Therapeutics: Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Membership on an entity's Board of Directors or advisory committees, Research Funding; SpringWorks Therapeutics: Research Funding. OffLabel Disclosure: JSMD194 - an oral gamma secretase inhibitor
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Jia, Yunpeng, Qizhou Wang, Jingjing Qiao, Binbin Feng, Xueting Zhou, Lijun Jin, Yingting Feng, Duxia Yang, Chenze Lu e Xiangxian Ying. "Cascading Old Yellow Enzyme, Alcohol Dehydrogenase and Glucose Dehydrogenase for Selective Reduction of (E/Z)-Citral to (S)-Citronellol". Catalysts 11, n.º 8 (30 de julho de 2021): 931. http://dx.doi.org/10.3390/catal11080931.
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Citronellol is a kind of unsaturated alcohol with rose-like smell and its (S)-enantiomer serves as an important intermediate for organic synthesis of (-)-cis-rose oxide. Chemical methods are commonly used for the synthesis of citronellol and its (S)-enantiomer, which suffers from severe reaction conditions and poor selectivity. Here, the first one-pot double reduction of (E/Z)-citral to (S)-citronellol was achieved in a multi-enzymatic cascade system: N-ethylmaleimide reductase from Providencia stuartii (NemR-PS) was selected to catalyze the selective reduction of (E/Z)-citral to (S)-citronellal, alcohol dehydrogenase from Yokenella sp. WZY002 (YsADH) performed the further reduction of (S)-citronellal to (S)-citronellol, meanwhile a variant of glucose dehydrogenase from Bacillus megaterium (BmGDHM6), together with glucose, drove efficient NADPH regeneration. The Escherichia coli strain co-expressing NemR-PS, YsADH, and BmGDHM6 was successfully constructed and used as the whole-cell catalyst. Various factors were investigated for achieving high conversion and reducing the accumulation of the intermediate (S)-citronellal and by-products. 0.4 mM NADP+ was essential for maintaining high catalytic activity, while the feeding of the cells expressing BmGDHM6 effectively eliminated the intermediate and by-products and shortened the reaction time. Under optimized conditions, the bio-transformation of 400 mM citral caused nearly complete conversion (>99.5%) to enantio-pure (S)-citronellol within 36 h, demonstrating promise for industrial application.
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Sowa-Rogozińska, Natalia, Hanna Sominka, Jowita Nowakowska-Gołacka, Kirsten Sandvig e Monika Słomińska-Wojewódzka. "Intracellular Transport and Cytotoxicity of the Protein Toxin Ricin". Toxins 11, n.º 6 (18 de junho de 2019): 350. http://dx.doi.org/10.3390/toxins11060350.
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Ricin can be isolated from the seeds of the castor bean plant (Ricinus communis). It belongs to the ribosome-inactivating protein (RIP) family of toxins classified as a bio-threat agent due to its high toxicity, stability and availability. Ricin is a typical A-B toxin consisting of a single enzymatic A subunit (RTA) and a binding B subunit (RTB) joined by a single disulfide bond. RTA possesses an RNA N-glycosidase activity; it cleaves ribosomal RNA leading to the inhibition of protein synthesis. However, the mechanism of ricin-mediated cell death is quite complex, as a growing number of studies demonstrate that the inhibition of protein synthesis is not always correlated with long term ricin toxicity. To exert its cytotoxic effect, ricin A-chain has to be transported to the cytosol of the host cell. This translocation is preceded by endocytic uptake of the toxin and retrograde traffic through the trans-Golgi network (TGN) and the endoplasmic reticulum (ER). In this article, we describe intracellular trafficking of ricin with particular emphasis on host cell factors that facilitate this transport and contribute to ricin cytotoxicity in mammalian and yeast cells. The current understanding of the mechanisms of ricin-mediated cell death is discussed as well. We also comment on recent reports presenting medical applications for ricin and progress associated with the development of vaccines against this toxin.
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Morena, A. Gala, Sílvia Pérez-Rafael e Tzanko Tzanov. "Lignin-Based Nanoparticles as Both Structural and Active Elements in Self-Assembling and Self-Healing Multifunctional Hydrogels for Chronic Wound Management". Pharmaceutics 14, n.º 12 (30 de novembro de 2022): 2658. http://dx.doi.org/10.3390/pharmaceutics14122658.
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Efficient wound healing is feasible when the dressing materials simultaneously target multiple factors causing wound chronicity, such as deleterious proteolytic and oxidative enzymes and bacterial infection. Herein, entirely bio-based multifunctional self-assembled hydrogels for wound healing were developed by simply mixing two biopolymers, thiolated hyaluronic acid (HA-SH) and silk fibroin (SF), with lignin-based nanoparticles (NPs) as both structural and functional elements. Sono-enzymatic lignin modification with natural phenolic compounds results in antibacterial and antioxidant phenolated lignin nanoparticles (PLN) capable of establishing multiple interactions with both polymers. These strong and dynamic polymer-NP interactions endow the hydrogels with self-healing and shear-thinning properties, and pH-responsive NP release is triggered at neutral to alkaline pH (7–9). Despite being a physically crosslinked hydrogel, the material was stable for at least 7 days, and its mechanical and functional properties can be tuned depending on the polymer and NP concentration. Furthermore, human skin cells in contact with the nanocomposite hydrogels for 7 days showed more than 93% viability, while the viability of clinically relevant Staphylococcus aureus and Pseudomonas aeruginosa was reduced by 99.7 and 99.0%, respectively. The hydrogels inhibited up to 52% of the activity of myeloperoxidase and matrix metalloproteinases, responsible for wound chronicity, and showed a strong antioxidant effect, which are crucial features promoting wound healing.
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Chansuwan, Worrapanit, Matthawan Khamhae e Nualpun Sirinupong. "Hydrolase-treated royal jelly attenuates LPS-induced inflammation and IgE-antigen-mediated allergic reaction". Functional Foods in Health and Disease 10, n.º 3 (30 de março de 2020): 127. http://dx.doi.org/10.31989/ffhd.v10i3.694.
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Background: Royal jelly (RJ) is one of the most effectual and beneficial remedies for human beings and currently utilized in many sectors, ranging from the pharmaceutical and food industries to cosmetic and manufacturing sectors due to RJ possessing many bio-therapeutical activities including anti-tumor, antimicrobial and antioxidant activities, vasodilative and hypotensive activities, as well as growth-stimulating, infection-preventing, anti-hypercholesterolemic and anti-inflammatory activities. However, some reports showing direct consumption of RJ can lead to severe allergic reaction and has been linked with acute asthma, dermatitis, and life-threatening anaphylaxis. Thus, this research purposes to explore the potential anti-inflammatory and anti-allergic activities of hydrolyzed RJ as a function of enzyme and the extent of hydrolysis.Methods: RJ was enzymatically hydrolyzed with three commercial enzymes (AlcalaseÒ, FlavourzymeÒ and ProtamexÒ). Anti-inflammatory activity of the hydrolysates was measured by their inhibitory effect on nitric oxide (NO) production of lipopolysaccharide (LPS)-stimulated RAW264.7 macrophage cells. Anti-allergy was determined from the ability of the hydrolysates to inhibit b-hexsosaminidase (b-HEX) release from RBL-2H3 mast cells. Cytotoxicity was also investigated in both RAW264.7 macrophage cells and RBL-2H3 mast cells.Results: The electrophoretic profiles indicated that AlcalaseÒ and FlavourzymeÒ hydrolysates did not show the presence of proteins causing allergic reaction after 60 mins of hydrolysis while these allergens disappeared from ProtamexÒ hydrolysate at the hydrolysis time of 240 min. It was observed that hydrolyzed RJ showed no toxicity on RAW264.7 and RBL-2H3 cells. With the progression of hydrolysis, IC50 values of NO production inhibition significantly decreased while degree of hydrolysis (DH) was increased in all hydrolyzed samples (p < 0.05). Results of b-HEX release inhibition were found in the same fashion. FlavourzymeÒ hydrolysate at the 240 min time point effectively mitigated the oxidative stress and protected DNA in a dose dependent manner.Conclusions: RJ hydrolysates from FlavourzymeÒ resulted in peptides with anti-inflammatory activity as determined by the inhibition of NO production in LPS-stimulated RAW264.7 macrophage cells and anti-allergic property as measured by the suppression of degranulation of sensitized RBL-2H3 cells. Anti-inflammatory effect may be due to their anti-oxidative capability. Inhibition of b-HEX release may be due to their membrane-stabilizing effects or/and blockade of IgE antibody binding to its receptors.Keywords: anti-inflammation, enzymatic hydrolysate, royal jelly, anti-allergy
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Akintunde, Jacob K., e Ganiyu Oboh. "Orginal Article. Nephritic cell damage and antioxidant status in rats exposed to leachate from battery recycling industry". Interdisciplinary Toxicology 9, n.º 1 (1 de março de 2016): 1–11. http://dx.doi.org/10.1515/intox-2016-0001.
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Abstract Limited studies have assessed the toxic effect of sub-acute and sub-chronic exposure of leachate (mixture of metals) in mammalian kidney. The sub-acute and sub-chronic exposure of mature male Wistar-strain albino rats (200-220 g) were given by oral administration with leachate from Elewi Odo municipal battery recycling industry (EOMABRIL) for period of 7 and 60 days respectively, at different concentrations (20%, 40%, 60%, 80% and 100%). This was to evaluate its toxic effects on male renal functions using biomarkers of oxidative stress and nephro-cellular damage. Control groups were treated equally, but given distilled water instead of the leachate. All the groups were fed with the same standard food and had free access to drinking water. Following the exposure, results showed that the treatment induced systemic toxicity at the doses tested by causing a significant (p<0.05) alteration in enzymatic antioxidantscatalase (CAT) and superoxide dismutase (SOD) in the kidneys which resulted into elevated levels of malonaldehyde (MDA). Reduced glutathione (GSH) levels were found to be significantly (p<0.05) depleted relative to the control group. Considerable renal cortical congestion and numerous tubules with protein casts were observed in the lumen of EOMABRIL-treated rats. These findings conclude that possible mechanism by which EOMABRIL at the investigated concentrations elicits nephrotoxicity could be linked to the individual, additive, synergistic or antagonistic interactions of this mixture of metals with the renal bio-molecules, alteration of kidney detoxifying enzymes and necrosis of nephritic tubular epithelial cells.