RESUMEN
Among the enzymes derived from fungus that act on polysaccharides, lytic polysaccharide monooxygenase (LPMOs) has emerged as a new member with complex reaction mechanisms and high efficiency in dealing with recalcitrant crystalline polysaccharides. This study reported the characteristics, structure, and biochemical properties of a novel LPMO from Talaromyces sedimenticola (namely MaLPMO9K) obtained from the Mariana Trench. MaLPMO9K was a multi-domain protein combined with main body and a carbohydrate-binding module. It was heterologously expressed in E. coli for analyzing peroxidase activity in reactions with the substrate 2,6-DMP, where H2O2 serves as a co-substrate. Optimal peroxidase activity for MaLPMO9K was observed at pH 8 and 25 °C, achieving the best Vmax value of 265.2 U·g-1. In addition, MaLPMO9K also demonstrated the ability to treat cellulose derivatives, and cellobiose substrates without the presence of reducing agents.
Asunto(s)
Celulosa , Oxigenasas de Función Mixta , Oxidación-Reducción , Oxigenasas de Función Mixta/metabolismo , Oxigenasas de Función Mixta/química , Celulosa/metabolismo , Celulosa/química , Talaromyces/enzimología , Especificidad por Sustrato , Concentración de Iones de Hidrógeno , Sustancias Reductoras/química , Polisacáridos/metabolismo , Polisacáridos/química , Peróxido de Hidrógeno/metabolismo , Cinética , Proteínas Fúngicas/metabolismo , Proteínas Fúngicas/química , Organismos AcuáticosRESUMEN
The environmental benefits of utilizing protease as a biocatalyst for wool shrink-resist finishing have been widely recognized. However, the efficacy of individual protease treatment is unsatisfactory due to its incapability towards the outermost cuticle layer of wool fibers that contains hydrophobic fatty acids. In order to weaken the structural integrity of the highly cross-linked scales and promote the enzymatic anti-felting, sodium sulfite and tris (2-carboxyethyl) phosphine hydrochloride (TCEP) were employed in combination with papain, respectively, aiming at obtaining a low shrinkage without unacceptable fiber damages. Based on the synergistic effect of papain and TCEP, the edges of wool scales were slightly destroyed by the reduction of disulfide bonds, accompanied by enzymatic hydrolysis of the keratin component. Through the controlled reduction and hydrolysis of wool scales, satisfactory anti-felting result was achieved without causing severe damage to the fiber interiors. In the presence of 0.25 g/L TCEP and 25 U/mL papain, the area shrinkage of wool fabric decreased to approximately 6 %, with a low strength loss of less than 8 %. Meanwhile, the dyeing behavior of the wool fabric under low-temperature conditions was dramatically improved, leading to decreased energy consumption during production. The present work provides an alternative for eco-friendly finishing of wool fabrics, which can be applied commercially.
Asunto(s)
Disulfuros , Papaína , Lana , Papaína/química , Animales , Lana/química , Disulfuros/química , Sustancias Reductoras/química , Sulfitos/química , Sulfitos/farmacología , Fosfinas/química , Fibra de Lana , Hidrólisis , TextilesRESUMEN
Hydrotalcite-silver (HT-Ag) nanoparticles have been involved in various daily crucial applications, such as antibacterial, photocatalytic, adsorption, etc. There are many approaches to synthesizing silver nanoparticles (AgNPs) decorated on hydrotalcite (HT) surface and the most used approach is using a strong reducing agent. Thus, affordable but effective "green" reducing agents - Syzygium nervosum leaf extract, are taken into account in this work to solve several issues related to chemical reducing agents. This work aimed to assess the effect of Syzygium nervosum leaf extract as a reducing agent for green synthesis of AgNPs on HT through an optimizing process using response surface methodology (RSM) and the Box-Benken model. The optimal conditions for the synthesis of AgNPs on HT include a reaction time of 6.15â hours, a reaction temperature of 50 °C, and the ratio of diluted Syzygium nervosum leaf extract to reduce AgNO3 of 50.37â mL/mg. Under the optimal conditions, the yield of the reduction reaction reached 77.54 %, close to the theoretical value of 76.97 %. The optimization model was suitable for the experiment data. Besides, the morphology, density, and characteristics of AgNPs on the surface of HT layers have been determined by using Ultraviolet-visible spectroscopy, Field emission scanning electron microscopy (FESEM), High-resolution transmission electron microscopy (HR-TEM), selected area diffraction, X-ray diffraction, Dynamic light scattering (DLS), Infrared (IR) spectroscopy, Fluorescence emission spectroscopy (FE), Brunauer-Emmett-Teller (BET) methods. The spherical AgNPs were synthesized successfully on the surface of HT with the average particle size of 13.0±1.1â nm. Interestingly, HT-Ag hybrid materials can inhibit strongly the growth of E. coli, S. aureus as well as two antibiotic resistance bacterial strains, P. stutzeri B27, and antibiotic resistance E. coli. Especially, the antibacterial activity quantification and durability of the HT-Ag hybrid materials were also tested. Overall, the HT-Ag hybrid materials are very promising for application in material science and biomedicine fields.
Asunto(s)
Hidróxido de Aluminio , Tecnología Química Verde , Hidróxido de Magnesio , Nanopartículas del Metal , Extractos Vegetales , Plata , Syzygium , Plata/química , Nanopartículas del Metal/química , Syzygium/química , Hidróxido de Magnesio/química , Extractos Vegetales/química , Hidróxido de Aluminio/química , Sustancias Reductoras/química , Hojas de la Planta/química , Antibacterianos/química , Antibacterianos/síntesis química , Antibacterianos/farmacología , Tamaño de la Partícula , Pruebas de Sensibilidad Microbiana , Staphylococcus aureus/efectos de los fármacos , Escherichia coli/efectos de los fármacos , Propiedades de SuperficieRESUMEN
A challenge to successfully implementing an injection-based remedial treatment in aquifers is to ensure that the oxidative reaction is efficient and lasts long enough to contact the contaminated plume. Our objective was to determine the efficacy of zinc ferrite nanocomposites (ZnFe2O4) and sulfur-containing reductants (SCR) (i.e., dithionite; DTN and bisulfite; BS) to co-activate persulfate (S2O82-; PS) and treat herbicide-contaminated water. We also evaluated the ecotoxicity of the treated water. While both SCRs delivered excellent PS activation in a 1:0.4 ratio (PS:SCR), the reaction was relatively short-lived. By including ZnFe2O4 in the PS/BS or PS/DTN activations, herbicide degradation rates dramatically increased by factors of 2.5 to 11.3. This was due to the SO4- and OH reactive radical species that formed. Radical scavenging experiments and ZnFe2O4 XPS spectra results revealed that SO4- was the dominant reactive species that originated from S(IV)/PS activation in solution and from the Fe(II)/PS activation that occurred on the ZnFe2O4 surface. Based on liquid chromatography mass spectrometry (LC-MS), atrazine and alachlor degradation pathways are proposed that involve both dehydration and hydroxylation. In 1-D column experiments, five different treatment scenarios were run using 14C-labeled and unlabeled atrazine, and 3H2O to quantify changes in breakthrough curves. Our results confirmed that ZnFe2O4 successfully prolonged the PS oxidative treatment despite the SCR being completely dissociated. Toxicity testing showed treated 14C-atrazine was more biodegradable than the parent compound in soil microcosms. Post-treatment water (25 %, v/v) also had less impact on both Zea Mays L. and Vigna radiata L. seedling growth, but more impact on root anatomies, while ≤4 % of the treated water started to exert cytotoxicity (<80 % viability) on ELT3 cell lines. Overall, the findings confirm that ZnFe2O4/SCR/PS reaction is efficient and relatively longer lasting in treating herbicide-contaminated groundwater.
Asunto(s)
Compuestos Férricos , Agua Subterránea , Herbicidas , Sustancias Reductoras , Compuestos de Azufre , Contaminantes Químicos del Agua , Purificación del Agua , Compuestos de Zinc , Herbicidas/química , Herbicidas/metabolismo , Agua Subterránea/química , Compuestos de Zinc/química , Compuestos de Azufre/química , Sustancias Reductoras/química , Compuestos Férricos/química , Atrazina/química , Atrazina/metabolismo , Plantones/efectos de los fármacos , Plantones/crecimiento & desarrollo , Línea Celular , Restauración y Remediación Ambiental , Contaminantes Químicos del Agua/química , Contaminantes Químicos del Agua/metabolismo , Nanoestructuras/química , Purificación del Agua/métodos , Supervivencia Celular/efectos de los fármacosRESUMEN
Iron-associated reductants play a crucial role in providing electrons for various reductive transformations. However, developing reliable predictive tools for estimating abiotic reduction rate constants (logk) in such systems has been impeded by the intricate nature of these systems. Our recent study developed a machine learning (ML) model based on 60 organic compounds toward one soluble Fe(II)-reductant. In this study, we built a comprehensive kinetic data set covering the reactivity of 117 organic and 10 inorganic compounds toward four major types of Fe(II)-associated reductants. Separate ML models were developed for organic and inorganic compounds, and the feature importance analysis demonstrated the significance of resonance structures, reducible functional groups, reductant descriptors, and pH in logk prediction. Mechanistic interpretation validated that the models accurately learned the impact of various factors such as aromatic substituents, complexation, bond dissociation energy, reduction potential, LUMO energy, and dominant reductant species. Finally, we found that 38% of the 850,000 compounds in the Distributed Structure-Searchable Toxicity (DSSTox) database contain at least one reducible functional group, and the logk of 285,184 compounds could be reasonably predicted using our model. Overall, the study is a significant step toward reliable predictive tools for anticipating abiotic reduction rate constants in iron-associated reductant systems.
Asunto(s)
Hierro , Sustancias Reductoras , Sustancias Reductoras/química , Oxidación-Reducción , Hierro/química , Compuestos Orgánicos , Compuestos Ferrosos/químicaRESUMEN
Sediment-associated Fe(II) is a critical reductant for immobilizing groundwater contaminants, such as Cr(VI). The reduction reactivity of sediment-associated Fe(II) is dependent on its binding environment and influenced by the biogeochemical transformation of other elements (i.e., C, N and Mn), challenging the description and prediction of the reactivity of Fe(II) in natural sediments. Here, anaerobic batch experiments were conducted to study the variation in sediment-associated Fe(II) reactivity toward Cr(VI) in natural sediments collected from an intensive agricultural area located in Guangxi, China, where nitrate is a common surface water and groundwater contaminant. Then, a process-based model was developed to describe the coupled biogeochemical processes of C, N, Mn, Fe, and Cr. In the process-based model, Cr(VI) reduction by sediment-associated Fe(II) was described using a previously developed multirate model, which categorized the reactive Fe(II) into three fractions based on their extractabilities in sodium acetate and HCl solutions. The experimental results showed that Fe(II) generation was inhibited by NO3- and/or NO2-. After NO3- and NO2- were exhausted, the Fe(II) content and its reduction rate toward Cr(VI) increased rapidly. As the Fe(II) content increased, the three reactive Fe(II) fractions exhibited approximately linear correlations with aqueous Fe(II) concentrations ( [Formula: see text] ), which was probably driven by sorptive equilibrium and redox equilibrium between aqueous and solid phases. The model results indicated that the reaction rate constants of the three Fe(II) fractions (kn) significantly increased with incubation time, and log(kn) correlated well with [Formula: see text] [ [Formula: see text] , [Formula: see text] and [Formula: see text] ]. The numerical model developed in this study provides an applicable method to describe and predict Cr(VI) removal from groundwater under dynamic redox conditions.
Asunto(s)
Sustancias Reductoras , Contaminantes Químicos del Agua , Cinética , Sustancias Reductoras/química , Nitratos , Acetato de Sodio , Dióxido de Nitrógeno , China , Cromo/química , Oxidación-Reducción , Contaminantes Químicos del Agua/química , Agua/química , Compuestos Ferrosos/químicaRESUMEN
Luminescent hydrogels show extensive applications in many fields because of their excellent optical properties. Although there are many matrixes used to prepare luminescent hydrogels, the synthesis of protein-based luminescent hydrogels is still urgently needed to explore due to their good biodegradability and biocompatibility. In this work, a color-tunable, self-healing protein-based luminescent hydrogel consisting of bovine serum albumin (BSA) and lanthanide complexes is prepared via reductant-triggered gelation. Firstly, a bifunctional organic ligand named 4-(phenylsulfonyl)-pyridine-2,6-dicarboxylic acid (4-PSDPA) is synthesized, which can react with thiol groups and effectively sensitize the luminescence of Eu3+ and Tb3+ ions. Then, the BSA is treated with a reducing agent tris(2-carboxyethyl)phosphine (TCEP) to produce thiol groups. And the newly formed thiol groups can re-match to form disulfide bonds between two BSA molecules or react with Ln(4-PSDPA)3 complexes, resulting in the formation of an albumin-based luminescent hydrogel. Furthermore, the self-healing, biodegradability and biocompatibility of albumin-based hydrogels have also been demonstrated. We expect that the newly developed multifunctional protein-based hydrogels will find potential applications in the fields of biomedical engineering and optical devices.
Asunto(s)
Hidrogeles/química , Elementos de la Serie de los Lantanoides/química , Luminiscencia , Sustancias Reductoras/química , Materiales Biocompatibles , Fenómenos Químicos , Técnicas de Química Sintética , Humanos , Hidrogeles/síntesis química , Ensayo de Materiales , Fenómenos Mecánicos , Albúmina Sérica Bovina/química , Análisis EspectralRESUMEN
The syntheses of four new tunable homogeneous organic reductants based on a tetraaminoethylene scaffold are reported. The new reductants have enhanced air stability compared to current homogeneous reductants for metal-mediated reductive transformations, such as cross-electrophile coupling (XEC), and are solids at room temperature. In particular, the weakest reductant is indefinitely stable in air and has a reduction potential of -0.85 V versus ferrocene, which is significantly milder than conventional reductants used in XEC. All of the new reductants can facilitate C(sp2)-C(sp3) Ni-catalyzed XEC reactions and are compatible with complex substrates that are relevant to medicinal chemistry. The reductants span a range of nearly 0.5 V in reduction potential, which allows for control over the rate of electron transfer events in XEC. Specifically, we report a new strategy for controlled alkyl radical generation in Ni-catalyzed C(sp2)-C(sp3) XEC. The key to our approach is to tune the rate of alkyl radical generation from Katritzky salts, which liberate alkyl radicals upon single electron reduction, by varying the redox potentials of the reductant and Katritzky salt utilized in catalysis. Using our method, we perform XEC reactions between benzylic Katritzky salts and aryl halides. The method tolerates a variety of functional groups, some of which are particularly challenging for most XEC transformations. Overall, we expect that our new reductants will both replace conventional homogeneous reductants in current reductive transformations due to their stability and relatively facile synthesis and lead to the development of novel synthetic methods due to their tunability.
Asunto(s)
Alquenos/química , Aminas/química , Compuestos Heterocíclicos con 1 Anillo/química , Sustancias Reductoras/química , Alquenos/síntesis química , Aminas/síntesis química , Compuestos Heterocíclicos con 1 Anillo/síntesis química , Estructura Molecular , Oxidación-Reducción , Sustancias Reductoras/síntesis químicaRESUMEN
The analysis of total vitamin C content in food is most frequently performed by reducing dehydroascorbic acid to ascorbic acid, which is then assayed with the technique of high-performance liquid chromatography combined with spectrophotometric detection. Tris(2-carboxyethyl)phosphine is currently the only agent in use that efficiently reduces dehydroascorbic acid at pH < 2. Therefore, there is a continued need to search for new reducing agents that will display a high reactivity and stability in acidic solutions. The objective of the study was to verify the applicability of unithiol and tris(hydroxypropyl)phosphine for a reducing dehydroascorbic acid in an extraction medium with pH < 2. The conducted validation of the newly developed method of determining the total content of vitamin C using tris(hydroxypropyl)phosphine indicates its applicability for food analysis. The method allows obtaining equivalent results compared to the method based on the use of tris(2-carboxyethyl)phosphine. The low efficiency of dehydroascorbic acid reduction with the use of unithiol does not allow its application as a new reducing agent in vitamin C analysis.
Asunto(s)
Ácido Ascórbico/química , Ácido Deshidroascórbico/química , Sustancias Reductoras/química , Cromatografía Líquida de Alta Presión/métodos , Alimentos , Análisis de los Alimentos/métodos , Indicadores y Reactivos/química , Fosfinas/químicaRESUMEN
[FeFe] hydrogenases are highly active enzymes for interconverting protons and electrons with hydrogen (H2). Their active site H-cluster is formed of a canonical [4Fe-4S] cluster ([4Fe-4S]H) covalently attached to a unique [2Fe] subcluster ([2Fe]H), where both sites are redox active. Heterolytic splitting and formation of H2 takes place at [2Fe]H, while [4Fe-4S]H stores electrons. The detailed catalytic mechanism of these enzymes is under intense investigation, with two dominant models existing in the literature. In one model, an alternative form of the active oxidized state Hox, named HoxH, which forms at low pH in the presence of the nonphysiological reductant sodium dithionite (NaDT), is believed to play a crucial role. HoxH was previously suggested to have a protonated [4Fe-4S]H. Here, we show that HoxH forms by simple addition of sodium sulfite (Na2SO3, the dominant oxidation product of NaDT) at low pH. The low pH requirement indicates that sulfur dioxide (SO2) is the species involved. Spectroscopy supports binding at or near [4Fe-4S]H, causing its redox potential to increase by â¼60 mV. This potential shift detunes the redox potentials of the subclusters of the H-cluster, lowering activity, as shown in protein film electrochemistry (PFE). Together, these results indicate that HoxH and its one-electron reduced counterpart Hred'H are artifacts of using a nonphysiological reductant, and not crucial catalytic intermediates. We propose renaming these states as the "dithionite (DT) inhibited" states Hox-DTi and Hred-DTi. The broader potential implications of using a nonphysiological reductant in spectroscopic and mechanistic studies of enzymes are highlighted.
Asunto(s)
Biocatálisis , Ditionita/química , Hidrogenasas/química , Proteínas Hierro-Azufre/química , Sustancias Reductoras/química , Proteínas Algáceas/química , Proteínas Bacterianas/química , Chlamydomonas reinhardtii/enzimología , Clostridium/enzimología , Desulfovibrio desulfuricans/enzimología , Hidrógeno/química , Oxidación-Reducción , Sulfitos/química , Dióxido de Azufre/químicaRESUMEN
A new nonheme iron(II) complex, FeII (Me3 TACN)((OSiPh2 )2 O) (1), is reported. Reaction of 1 with NO(g) gives a stable mononitrosyl complex Fe(NO)(Me3 TACN)((OSiPh2 )2 O) (2), which was characterized by Mössbauer (δ=0.52â mm s-1 , |ΔEQ |=0.80â mm s-1 ), EPR (S=3/2), resonance Raman (RR) and Fe K-edge X-ray absorption spectroscopies. The data show that 2 is an {FeNO}7 complex with an S=3/2 spin ground state. The RR spectrum (λexc =458â nm) of 2 combined with isotopic labeling (15 N, 18 O) reveals ν(N-O)=1680â cm-1 , which is highly activated, and is a nearly identical match to that seen for the reactive mononitrosyl intermediate in the nonheme iron enzyme FDPnor (ν(NO)=1681â cm-1 ). Complex 2 reacts rapidly with H2 O in THF to produce the N-N coupled product N2 O, providing the first example of a mononuclear nonheme iron complex that is capable of converting NO to N2 O in the absence of an exogenous reductant.
Asunto(s)
Compuestos Ferrosos/química , Óxido Nítrico/química , Óxido Nitroso/química , Sustancias Reductoras/química , Conformación MolecularRESUMEN
Listeria monocytogenes is a Gram-positive, food-borne pathogen that lives a biphasic lifestyle, cycling between the environment and as a facultative intracellular pathogen of mammals. Upon entry into host cells, L. monocytogenes upregulates expression of glutathione synthase (GshF) and its product, glutathione (GSH), which is an allosteric activator of the master virulence regulator PrfA. Although gshF mutants are highly attenuated for virulence in mice and form very small plaques in host cell monolayers, these virulence defects can be fully rescued by mutations that lock PrfA in its active conformation, referred to as PrfA*. While PrfA activation can be recapitulated in vitro by the addition of reducing agents, the precise biological cue(s) experienced by L. monocytogenes that lead to PrfA activation are not known. Here we performed a genetic screen to identify additional small-plaque mutants that were rescued by PrfA* and identified gloA, which encodes glyoxalase A, a component of a GSH-dependent methylglyoxal (MG) detoxification system. MG is a toxic byproduct of metabolism produced by both the host and pathogen, which if accumulated, causes DNA damage and protein glycation. As a facultative intracellular pathogen, L. monocytogenes must protect itself from MG produced by its own metabolic processes and that of its host. We report that gloA mutants grow normally in broth, are sensitive to exogenous MG and severely attenuated upon IV infection in mice, but are fully rescued for virulence in a PrfA* background. We demonstrate that transcriptional activation of gshF increased upon MG challenge in vitro, and while this resulted in higher levels of GSH for wild-type L. monocytogenes, the glyoxalase mutants had decreased levels of GSH, presumably due to the accumulation of the GSH-MG hemithioacetal adduct. These data suggest that MG acts as a host cue that leads to GSH production and activation of PrfA.
Asunto(s)
Proteínas Bacterianas/metabolismo , Glutatión/metabolismo , Lactoilglutatión Liasa/metabolismo , Listeria monocytogenes/fisiología , Listeriosis/microbiología , Piruvaldehído/metabolismo , Virulencia , Animales , Proteínas Bacterianas/genética , Femenino , Regulación Bacteriana de la Expresión Génica , Inactivación Metabólica , Lactoilglutatión Liasa/genética , Listeriosis/metabolismo , Ratones , Mutación , Piruvaldehído/química , Sustancias Reductoras/química , Activación TranscripcionalRESUMEN
Herein, we disclose that electrochemical stimulation induces new photocatalytic activity from a range of structurally diverse conventional photocatalysts. These studies uncover a new electron-primed photoredox catalyst capable of promoting the reductive cleavage of strong C(sp2 )-N and C(sp2 )-O bonds. We illustrate several examples of the synthetic utility of these deeply reducing but otherwise safe and mild catalytic conditions. Finally, we employ electrochemical current measurements to perform a reaction progress kinetic analysis. This technique reveals that the improved activity of this new system is a consequence of an enhanced catalyst stability profile.
Asunto(s)
Técnicas Electroquímicas , Compuestos Orgánicos/química , Sustancias Reductoras/química , Catálisis , Estructura Molecular , Oxidación-Reducción , Procesos FotoquímicosRESUMEN
Biology uses well-known redox mechanisms for energy harvesting (e.g., respiration), biosynthesis, and immune defense (e.g., oxidative burst), and now we know biology uses redox for systems-level communication. Currently, we have limited abilities to "eavesdrop" on this redox modality, which can be contrasted with our abilities to observe and actuate biology through its more familiar ionic electrical modality. In this Perspective, we argue that the coupling of electrochemistry with diffusible mediators (electron shuttles) provides a unique opportunity to access the redox communication modality through its electrical features. We highlight previous studies showing that mediated electrochemical probing (MEP) can "communicate" with biology to acquire information and even to actuate specific biological responses (i.e., targeted gene expression). We suggest that MEP may reveal an extent of redox-based communication that has remained underappreciated in nature and that MEP could provide new technological approaches for redox biology, bioelectronics, clinical care, and environmental sciences.
Asunto(s)
Biología/métodos , Electroquímica , Biomarcadores/análisis , Biomarcadores/química , Electroquímica/métodos , Oxidantes/química , Oxidación-Reducción , Estrés Oxidativo/fisiología , Especies Reactivas de Oxígeno/metabolismo , Sustancias Reductoras/químicaRESUMEN
CONTEXT: Pectin is a plant heteropolysaccharide that is biocompatible and biodegradable, enabling it to be an excellent reducing agent (green synthesis) for metallic nanoparticles (MNPs). Nevertheless, in the biological industry, pectin has been left behind in synthesising MNPs, for no known reason. OBJECTIVE: To systematically review the biological activities of pectin synthesised MNPs (Pe-MNPs). METHODS: The databases Springer Link, Scopus, ScienceDirect, Google Scholar, PubMed, Mendeley, and ResearchGate were systematically searched from the date of their inception until 10th February 2020. Pectin, green synthesis, metallic nanoparticles, reducing agent and biological activities were among the key terms searched. The data extraction was focussed on the biological activities of Pe-MNPs and reported following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) recommendations for systematic reviews. RESULTS: A total of 15 studies outlined 7 biological activities of Pe-MNPs in the only three metals that have been explored, namely silver (Ag), gold (Au) and cerium oxide (CeO2). The activities reported from the in vitro and in vivo studies were antimicrobial (9 studies), anticancer (2 studies), drug carrier (3 studies), non-toxic (4 studies), antioxidant (2 studies), wound healing (1 study) and anti-inflammation (1 study). CONCLUSIONS: This systematic review demonstrates the current state of the art of Pe-MNPs biological activities, suggesting that Ag and Au have potent antibacterial and anticancer/chemotherapeutic drug carrier activity, respectively. Further in vitro, in vivo, and clinical research is crucial for a better understanding of the pharmacological potential of pectin synthesised MNPs.
Asunto(s)
Tecnología Química Verde/métodos , Nanopartículas del Metal/química , Pectinas/química , Animales , Cerio/química , Portadores de Fármacos/química , Oro/química , Humanos , Sustancias Reductoras/química , Plata/químicaRESUMEN
In the present work, shape tailored Cu2O microparticles were synthesized by changing the nature of the reducing agent and studied subsequently. d-(+)-glucose, d-(+)-fructose, d-(+)xylose, d-(+)-galactose, and d-(+)-arabinose were chosen as reducing agents due to their different reducing abilities. The morpho-structural characteristics were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), and diffuse reflectance spectroscopy (DRS), while their photocatalytic activity was evaluated by methyl orange degradation under visible light (120 min). The results show that the number of carbon atoms in the sugars affect the morphology and particle size (from 250 nm to 1.2 µm), and differences in their degree of crystallinity and photocatalytic activity were also found. The highest activity was observed when glucose was used as the reducing agent.
Asunto(s)
Cobre/química , Luz , Sustancias Reductoras/química , Azúcares/química , Catálisis , Tamaño de la Partícula , Procesos Fotoquímicos , Propiedades de SuperficieRESUMEN
Spirocyclic nitroxyl radicals (SNRs) are stable paramagnetics bearing spiro-junction at a-, b-, or g-carbon atom of the nitroxide fragment, which is part of the heterocyclic system. Despite the fact that the first representatives of SNRs were obtained about 50 years ago, the methodology of their synthesis and their usage in chemistry and biochemical applications have begun to develop rapidly only in the last two decades. Due to the presence of spiro-function in the SNRs molecules, the latter have increased stability to various reducing agents (including biogenic ones), while the structures of the biradicals (SNBRs) comprises a rigid spiro-fused core that fixes mutual position and orientation of nitroxide moieties that favors their use in dynamic nuclear polarization (DNP) experiments. This first review on SNRs will give a glance at various strategies for the synthesis of spiro-substituted, mono-, and bis-nitroxides on the base of six-membered (piperidine, 1,2,3,4-tetrahydroquinoline, 9,9'(10H,10H')-spirobiacridine, piperazine, and morpholine) or five-membered (2,5-dihydro-1H-pyrrole, pyrrolidine, 2,5-dihydro-1H-imidazole, 4,5-dihydro-1H-imidazole, imidazolidine, and oxazolidine) heterocyclic cores.
Asunto(s)
Disciplinas de las Ciencias Naturales/métodos , Óxidos de Nitrógeno/química , Imidazoles/química , Imidazolidinas/química , Morfolinas/química , Oxazoles/química , Piperidinas/química , Pirrolidinas/química , Sustancias Reductoras/químicaRESUMEN
The drugs used to treat cutaneous leishmaniasis (CL) cannot effectively penetrate lesions. Nanogold and nanosilver have been used for treating or enhancing drug delivery in CL. The present study used Commiphora molmol (myrrh) to synthesize silver nanoparticles (MSNPs). The MSNPs were characterized using transmission electron microscopy and energy-dispersive spectroscopy. In addition, antiparasitic effect of myrrh silver nanoparticles (MSNPs) was assessed on Leishmania major both in vitro and in vivo. Five concentrations of MSNPs (10, 50, 80, 100, and 150 µl/100 µL) were used to study their effect on L. major cultures in vitro, and MSNPs were also applied topically to subcutaneous lesions in mice in vivo. The results showed that the MSNPs were 49.09 nm in size. MSNPs, showed a marked and significant (p ≤ 0.05) growth inhibition of L. major promastigotes which was concentration dependent. Overall, the higher concentrations (100, 150 µl/100 µL had a significantly greater inhibitory effect for the MSNPs in comparison to the chemical nanoparticles (CNPs) and pentostam at the same concentrations. Lesions healed completely in 21 d after MSNP treatment in vivo, while pentostam, a commercial drug, and CNPs showed a moderate healing effect on the lesions. Thus, MSNPs were more effective than pentostam and CNPs both in the in vivo and in vitro studies. MSNPs can therefore be promising candidates for various nanomedicine applications.
Asunto(s)
Commiphora/química , Excipientes/química , Tecnología Química Verde , Leishmania major/efectos de los fármacos , Leishmaniasis Cutánea/tratamiento farmacológico , Nanopartículas del Metal , Sustancias Reductoras/química , Compuestos de Plata/farmacología , Tripanocidas/farmacología , Animales , Modelos Animales de Enfermedad , Composición de Medicamentos , Leishmania major/crecimiento & desarrollo , Leishmania major/ultraestructura , Leishmaniasis Cutánea/parasitología , Ratones Endogámicos BALB C , Pruebas de Sensibilidad Parasitaria , Compuestos de Plata/síntesis química , Tripanocidas/síntesis químicaRESUMEN
Among phosphorus-based nanomaterials, layered black phosphorus and violet phosphorus have been actively explored in the past decade. However, methods for the synthesis of red phosphorus nanosheets (RPNSs) is lacking, even though red phosphorus (RP) is commercially available at low cost and has excellent chemical stability at room temperature. We report an efficient strategy for fabrication of RPNSs and doped RPNSs using cysteine as a reducing reagent. Data from inâ vitro and inâ vivo studies suggested that RPNSs can trigger production of reactive oxygen species, DNA damage, and subsequent autophagy-mediated cell death in a shape-dependent manner. Our findings provide a method for construction of layered RP nanomaterials and they present a unique mechanism for the application of phosphorus-based materials in nanomedicines.
Asunto(s)
Cisteína/química , Nanoestructuras/química , Fósforo/química , Células A549 , Animales , Apoptosis/efectos de los fármacos , Compuestos de Boro/química , Línea Celular , Daño del ADN/efectos de los fármacos , Ferroptosis/efectos de los fármacos , Humanos , Ratones , Ratones Desnudos , Nanoestructuras/uso terapéutico , Nanoestructuras/toxicidad , Neoplasias/tratamiento farmacológico , Neoplasias/patología , Especies Reactivas de Oxígeno/metabolismo , Sustancias Reductoras/química , Trasplante HeterólogoRESUMEN
The enzyme betaine aldehyde dehydrogenase (BADH EC 1.2.1.8) catalyzes the synthesis of glycine betaine (GB), an osmolyte and osmoprotectant. Also, it participates in several metabolic pathways in humans. All BADHs known have cysteine in the active site involved in the aldehyde binding, whereas the porcine kidney enzyme (pkBADH) also has a neighborhood cysteine, both sensitive to oxidation. The antineoplastic and immuno-suppressant pre-drug cyclophosphamide (CTX), and its bioactivation products, have two highly oxidating chlorine atoms. This work aimed to analyze the effect of CTX in the activity of porcine kidney betaine aldehyde dehydrogenase. PkBADH was incubated with varying CTX concentration (0 to 2.0 mM) at 25 °C and lost 50 % of its activity with 2.0 mM CTX. The presence of the coenzyme NAD+ (0.5 mM) decreased 95% the activity in 2.0 mM CTX. The substrate betaine aldehyde (0.05 and 0.4 mM, and the products NADH (0.1-0.5 mM) and GB (1 and 10 mM) did not have an effect on the enzyme inactivation by CTX. The reducing agents, dithiothreitol and ß-mercaptoethanol, reverted the pkBADH inactivation, but reduced glutathione (GSH) was unable to restore the enzyme activity. Molecular docking showed that CTX could enter at the enzyme active site, where its chlorine atoms may interact with the catalytic and the neighboring cysteines. The results obtained show that CTX inactivates the pkBADH due to oxidation of the catalytic cysteine or because it oxidizes catalytic and neighborhood cysteine, forming a disulfide bridge with a concomitant decrease in the activity of the enzyme.