RESUMEN
Cellobiose dehydrogenase (CDH, EC 1.1.99.18) is a glycoprotein having many biotechnological applications. In the present study, CDHs isolated from Phlebia lindtneri (PlCDH), Phanerochaete chrysosporium (PchCDH), Cerrena unicolor (CuCDH), and Pycnoporus sanguineus (PsCDH) were studied the first time for their ability to generate antioxidant and antimicrobial agents. The aim of the research was to evaluate the antioxidant and antimicrobial activity of systems composed of four CDHs and lactose or cellobiose as a reaction substrate. The free radical scavenging effect of free and immobilised enzymes was evaluated using the DPPH method. The lowest values of EC50 (10.04 ± 0.75 µg/ml) was noted for PlCDH/lactose and for PlCDH/cellobiose (12.06 ± 1.35 µg/ml). The EC50value reached 12.6 ± 1.51 µg/ml in the case of PsCDH/lactose and 15.96 ± 1.35 for PsCDH. The CDH preparations were also effectively immobilised in alginate (the immobilisation efficiency expressed as a protein yield ranged from 61.6 to 100 %). The operational stability expressed as a scavenging effect showed the possibility of using the alginate beads 4 times. Both the free and immobilised CDHs as well as the CDH/substrate were tested against Gram-negative Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, and Gram-positive Staphylococcus aureus ATCC 25923 bacteria. All samples, except PlCDH, were potentially effective in suppression of bacterial growth. The highest percentage of inhibition (100 %) was obtained for S. aureus bacteria using PsCDH and PchCDH with lactose as a substrate, whereas a slightly lesser effect was observed for E. coli and P. aeruginosa bacterial cells, i.e. 64.1 % and 86.5 % (PsCDH) and 94.1 % and 41.4 % (PchCDH), respectively. Furthermore, the concentrations of the reaction products (aldonic acids and hydrogen peroxide) were quantified and the surface morphology of the alginate beads was analysed using SEM visualisation.
Asunto(s)
Antiinfecciosos/aislamiento & purificación , Antiinfecciosos/farmacología , Antioxidantes/aislamiento & purificación , Antioxidantes/farmacología , Basidiomycota/enzimología , Deshidrogenasas de Carbohidratos/aislamiento & purificación , Deshidrogenasas de Carbohidratos/farmacología , Basidiomycota/aislamiento & purificación , Compuestos de Bifenilo/metabolismo , Deshidrogenasas de Carbohidratos/metabolismo , Celobiosa/metabolismo , Enzimas Inmovilizadas/farmacología , Escherichia coli/efectos de los fármacos , Escherichia coli/crecimiento & desarrollo , Lactosa/metabolismo , Pruebas de Sensibilidad Microbiana , Picratos/metabolismo , Pseudomonas aeruginosa/efectos de los fármacos , Pseudomonas aeruginosa/crecimiento & desarrollo , Staphylococcus aureus/efectos de los fármacos , Staphylococcus aureus/crecimiento & desarrollo , Madera/microbiologíaRESUMEN
The inhibitory effect of lactose oxidase on the growth of foodborne pathogens and spoilage microorganisms associated with dairy products was evaluated through an overlay inhibition assay. Lactose oxidase generates hydrogen peroxide via lactose oxidation into lactobionic acid. Escherichia coli O157:H7, Listeria monocytogenes, Salmonella enterica ser. Typhimurium, Staphylococcus aureus, Pseudomonas fragi, and Penicillium chrysogenum were used as indicators. A commercially available solution of lactose oxidase was applied at different concentrations (0, 0.12, 1.2, and 12 g/L) in 4 types of media [brain heart infusion agar (BHI), BHI + sodium thiocyanate (NaSCN), BHI + lactose, and BHI + NaSCN + lactose] to evaluate the effect of lactose and thiocyanate on microbial inhibition. Lactose oxidase inhibited the growth of all the indicators at a concentration of 12 g/L of the enzyme solution in the presence of lactose alone and in combination with NaSCN. However, supplementation with NaSCN had no effect on the magnitude of microbial inhibition. Staphylococcus aureus was the most sensitive pathogen, and Ps. fragi was the most sensitive of all the indicators in general to lactose oxidase. Listeria monocytogenes and Ps. fragi showed higher susceptibility to the antimicrobial effect of lactose oxidase at 6°C than at their corresponding optimum growth temperature. The inhibitory effect was attributed to the generation of hydrogen peroxide from the oxidation of lactose. Findings from this study demonstrate that lactose oxidase could be used as a novel approach to inhibit the growth of mold and bacteria. It could also be applied as a label-friendly preservative in dairy foods.
Asunto(s)
Bacterias/efectos de los fármacos , Deshidrogenasas de Carbohidratos/farmacología , Microbiología de Alimentos , Conservación de Alimentos , Animales , Bacterias/metabolismo , Deshidrogenasas de Carbohidratos/metabolismo , Recuento de Colonia Microbiana , Productos Lácteos , Temperatura , TiocianatosRESUMEN
The treatment of wound infection still constitutes a major threat in health care due to the increasing number of bacterial resistances and the difficulty of timely infection detection. Here, we present a smart antimicrobial system that is activated in case of infection based on elevated lysozyme activities. N-acetyl chitosan (degree of N-acetylation: 40%) was synthesized and hydrolysis by lysozyme in artificial wound fluid (AWF) was demonstrated. This resulted in the formation of N-acetylated chito oligosaccharides (COS) with a degree of polymerization of 2-5 units. The COS were shown to serve as substrate for cellobiose dehydrogenase (CDH) leading to the production of 1 mM antimicrobial hydrogen peroxide (H2 O2 ) after 24 h incubation at 37°C in AWF. Growth inhibition was seen upon incubation of Escherichia coli and Staphylococcus aureus with this chitosan-CDH system over 8 h. This approach represents the first self-regulating system for the infection responsive inhibition of bacterial growth in response to lysozyme as infection biomarker. Biotechnol. Bioeng. 2017;114: 416-422. © 2016 Wiley Periodicals, Inc.
Asunto(s)
Antiinfecciosos , Deshidrogenasas de Carbohidratos , Quitosano/química , Modelos Biológicos , Muramidasa , Infección de Heridas , Antiinfecciosos/química , Antiinfecciosos/farmacología , Deshidrogenasas de Carbohidratos/química , Deshidrogenasas de Carbohidratos/farmacología , Escherichia coli/efectos de los fármacos , Humanos , Muramidasa/química , Muramidasa/farmacología , Staphylococcus aureus/efectos de los fármacos , Infección de Heridas/microbiología , Infección de Heridas/prevención & controlRESUMEN
A new H(2)O(2)-generating pyranose oxidase was purified as a strong antifungal protein from an arbuscular mycorrhizal fungus, Tricholoma matsutake. The protein showed a molecular mass of 250 kDa in gel filtration, and probably consisted of four identical 62 kDa subunits. The protein contained flavin moiety and it oxidized D-glucose at position C-2. H(2)O(2) and D-glucosone produced by the pyranose oxidase reaction showed antifungal activity, suggesting these compounds were the molecular basis of the antifungal property. The V(max), K(m), and k(cat) for D-glucose were calculated to be 26.6 U/mg protein, 1.28 mM, and 111/s, respectively. The enzyme was optimally active at pH 7.5 to 8.0 and at 50 degrees C. The preferred substrate was D-glucose, but 1,5-anhydro-D-glucitol, L-sorbose, and D-xylose were also oxidized at a moderate level. The cDNA encodes a protein consisting of 564 amino acids, showing 35.1% identity to Coriolus versicolor pyranose oxidase. The recombinant protein was used for raising the antibody.
Asunto(s)
Basidiomycota/genética , Deshidrogenasas de Carbohidratos/genética , Hongos/efectos de los fármacos , Subunidades de Proteína/genética , Secuencia de Aminoácidos , Antifúngicos/farmacología , Basidiomycota/enzimología , Deshidrogenasas de Carbohidratos/química , Deshidrogenasas de Carbohidratos/farmacología , Clonación Molecular , Biblioteca de Genes , Glucosa/metabolismo , Peróxido de Hidrógeno/metabolismo , Cetosas/metabolismo , Datos de Secuencia Molecular , Subunidades de Proteína/química , Subunidades de Proteína/farmacología , Sorbosa/metabolismo , Especificidad por Sustrato , Xilosa/metabolismoRESUMEN
When glucose is the carbon source, the white rot fungus Pycnoporus cinnabarinus produces a characteristic red pigment, cinnabarinic acid, which is formed by laccase-catalyzed oxidation of the precursor 3-hydroxyanthranilic acid. When P. cinnabarinus was grown on media containing cellobiose or cellulose as the carbon source, the amount of cinnabarinic acid that accumulated was reduced or, in the case of cellulose, no cinnabarinic acid accumulated. Cellobiose-dependent quinone reducing enzymes, the cellobiose dehydrogenases (CDHs), inhibited the redox interaction between laccase and 3-hydroxyanthranilic acid. Two distinct proteins were purified from cellulose-grown cultures of P. cinnabarinus; these proteins were designated CDH I and CDH II. CDH I and CDH II were both monomeric proteins and had apparent molecular weights of about 81,000 and 101,000, respectively, as determined by both gel filtration and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The pI values were approximately 5.9 for CDH I and 3.8 for CDH II. Both CDHs used several known CDH substrates as electron acceptors and specifically adsorbed to cellulose. Only CDH II could reduce cytochrome c. The optimum pH values for CDH I and CDH II were 5.5 and 4.5, respectively. In in vitro experiments, both enzymes inhibited laccase-mediated formation of cinnabarinic acid. Oxidation intermediates of 3-hydroxyanthranilic acid served as endogenous electron acceptors for the two CDHs from P. cinnabarinus. These results demonstrated that in the presence of a suitable cellulose-derived electron donor, CDHs can regenerate fungal metabolites oxidized by laccase, and they also supported the hypothesis that CDHs act as links between cellulolytic and ligninolytic pathways.
Asunto(s)
Basidiomycota/enzimología , Deshidrogenasas de Carbohidratos/metabolismo , Oxazinas/metabolismo , Oxidorreductasas/metabolismo , Ácido 3-Hidroxiantranílico/metabolismo , Basidiomycota/metabolismo , Deshidrogenasas de Carbohidratos/farmacología , Cromatografía en Gel , Medios de Cultivo , Electroforesis en Gel de Poliacrilamida , Concentración de Iones de Hidrógeno , Lacasa , Oxidación-Reducción/efectos de los fármacos , Oxidorreductasas/farmacología , EspectrofotometríaRESUMEN
Phanerochete chrysosporium ligninase (+ H2O2) oxidized the lignin substructure-related compound acetosyringone to a phenoxy radical which was identified by ESR spectroscopy. Cellobiose:quinone oxidoreductase (CBQase) + cellobiose, previously suggested to be a phenoxy radical reducing system, was without effect on the radical. Ligninase polymerized guaiacol and it increased the molecular size of a synthetic lignin. These polymerizations, reflecting phenoxy radical coupling reactions, were also unaffected by the CBQase system. We conclude that ligninase catalyzes phenol polymerization via phenoxy radicals, which CBQase does not affect. The CBQase system also did not produce H2O2, and its physiological role remains obscure. Glucose oxidase + glucose did produce H2O2 as expected, but, like CBQase, it did not reduce the phenoxy radical of acetosyringone. Because intact cultures of P. chrysosporium depolymerize lignins, it is likely that phenol polymerization by ligninase is prevented or reversed in vivo by an as yet undescribed system.