Explore the vast range of titles available.

The composition of anthocyanins in cultivated Lycium ruthenicum Murray (CLM) before and after in vitro gastrointestinal digestion was determined using an HPLC system coupled with an electrospray ionization-time of flight mass spectrometry. The antioxidant activity and α-glucosidase inhibition of the anthocyanins before and after digestion were also studied. The results showed that most of the anthocyanins in CLM were found in glycosylated form, containing glycoside ligands. After digestion, the glycosylated anthocyanins were transformed to anthocyanidins (without glycol-ligands) which exhibited higher antioxidant activity comparatively. Interestingly, although the inhibitory activity of anthocyanins against α-glucosidase was increased by in vitro gastrointestinal digestion, as suggested by IC 50 value, the binding affinity of the anthocyanidins to α-glucosidase remained stable, as demonstrated by fluorescence quenching constant. This suggested that the anthocyanidins might have formed the anthocyanidin-α-glucosidase-substrate tertiary complex. Conclusively, in vitro gastrointestinal digestion may enhance the biological activities of CLM anthocyanins, regarding the antioxidant activity and α-glucosidase inhibition.

The effect of several carbon sources on the production of mycelial-bound β-glucosidase by Humicola grisea var. thermoidea in submerged fermentation was investigated. Maximum production occurred when cellulose was present in the culture medium, but higher specific activities were achieved with cellobiose or sugarcane bagasse. Xylose or glucose (1%) in the reaction medium stimulated β-glucosidase activity by about 2-fold in crude extracts from mycelia grown in sugarcane bagasse. The enzyme was purified by ammonium sulfate precipitation, followed by Sephadex G-200 and DEAE-cellulose chromatography, showing a single band in PAGE and SDS-PAGE. The β-glucosidase had a carbohydrate content of 43% and showed apparent molecular masses of 57 and 60 kDa, as estimated by SDS-PAGE and gel filtration, respectively. The optimal pH and temperature were 6.0 and 50℃, respectively. The purified enzyme was thermostable up to 60 min in water at 55℃ and showed half-lives of 7 and 14 min when incubated in the absence or presence of 50 mM glucose, respectively, at 60℃. The enzyme hydrolyzed p-nitrophenyl-β-D-glucopyranoside, p-nitrophenyl-β-D-galactopyranoside, p-nitrophenyl-β-D-fucopyranoside, p-nitrophenyl-β-D-xylopyranoside, o-nitrophenyl-beta-β-galactopyranoside, lactose, and cellobiose. The best synthetic and natural substrates were p-nitrophenyl-β-D-fucopyranoside and cellobiose, respectively. Purified enzyme activity was stimulated up to 2-fold by glucose or xylose at concentrations from 25 to 200 mM. The addition of purified or crude β-glucosidase to a reaction medium containing Trichoderma reesei cellulases increased the saccharification of sugarcane bagasse by about 50%. These findings suggest that H. grisea var. thermoidea β-glucosidase has a potential for biotechnological applications in the bioconversion of lignocellulosic materials.

A gram-negative bacterium, designated strain DAU5, was isolated from shrimp shell samples because it demonstrated high β-glucosidase activity. Through 16S rDNA gene sequence analysis the strain was identified as belonging to the genus Exiguobacterium. The β-glucosidase gene of Exiguobacterium sp. DAU5 was successfully cloned by the shotgun method. Nucleotide sequence determination by sodium dodecyl sulfate-ployacrylamide gel electrophoresis indicated that the gene for the enzyme contained 1,350 bp, was coded by 450 amino acids, and was 52 kDa. The polypeptide exhibits significant homology with other bacterial β-glucosidases and belongs to the Glycoside Hydrolase Family 1. The β-glucosidase was purified by a His-fusion purification system. The optimal pH and temperature of the enzyme were 7.0 and 45℃, respectively. The enzyme activity was strongly inhibited by Ca²+, and Li+, K+, Zn²+, Mg²+, Na²+, Ni²+, and EDTA partially inhibited the enzyme activity. The BglA showed the highest activity with p-NPG and MUG However, strain DAU5 β-glucosidase, which is for degradation of oligosaccharides, is expected to be useful for the fermentation of cellulose degradation and the transglycosylation of saccharides.

La diabetes es una de las principales causas de morbilidad y mortalidad en el mundo. Muchos estudios están dirigidos hacia la búsqueda de componentes dietarios que sean benéficos para su tratamiento y prevención. El objetivo del presente estudio fue examinar el efecto antioxidante e inhibitorio de α-glucosidasa y α-amilasa de extractos acuosos de canela (Cinnamomum zeylanicum), comino (Cumi­num cyminum), orégano (Origanum vulgare), pimienta negra (Piper nigrum) y clavo (Euge­nia caryophyllus), que son especias utiliza­das comúnmente en la cocina mexicana. Se prepararon extractos acuosos (50 °C durante 3 h) y se determinó el contenido de compues­tos fenólicos totales, actividad antioxidante y potencial inhibitorio in vitro de α-glucosidasa y α-amilasa. El contenido de compuestos fenólicos totales varió de 3.12 a 104.4 mg/g de muestra. Todos los extractos mostraron ac­tividad antioxidante que fue expresada como porcentaje de inhibición del radical DPPH- (30 % a 80 %) y capacidad inhibitoria de α-glucosidasa de 22 % a 70 %. La inhibición de la actividad α-amilasa se encontró de 0 % a 50 %. Los extractos acuosos de canela pre­sentaron mayor capacidad inhibitoria contra la acción de la α-glucosidasa y actividad con­tra el radical DPPH-, los extractos acuosos de orégano mostraron menor inhibición de la actividad α-glucosidasa y no presentaron inhibición contra la actividad α-amilasa. La efectividad inhibitoria de las enzimas y el contenido de compuestos fenólicos totales no presentó correlación. Sin em­bargo, se encontró una correlación entre la actividad antioxidante y el contenido de compuestos fenólicos totales (r2 = 0.94, P < 0.05). La inhibición de α-glucosidasa y α-amilasa es una de las formas terapéuti­cas para retardar la digestión y absorción de los carbohidratos y en consecuencia, la reducción de glucosa postprandial en sangre. El uso de especias culinarias con­sumidas en los platillos mexicanos podría representar un uso potencial durante los estados tempranos de hiperglicemia.

Cabbage plants respond to caterpillar (Pieris brassicae) herbivory by releasing a mixture of volatiles that makes them highly attractive to parasitic wasps (Cotesia glomerata) that attack the herbivores. Cabbage leaves that are artificially damaged and subsequently treated with gut regurgitant of P. brassicae caterpillars release a volatile blend similar to that of herbivore-damaged plants. We demonstrate the presence of beta-glucosidase in P. brassicae regurgitant. Leaves treated with commercial beta-glucosidase (from almonds) release a volatile blend similar to that of leaves treated with P. brassicae regurgitant. In a flight bioassay, leaves treated with almond beta-glucosidase are highly attractive to the parasitic wasp C. glomerata. Furthermore, the wasps do not discriminate between cabbage leaves treated with almond beta-glucosidase and leaves treated with larval regurgitant. beta-Glucosidase was also recorded in cabbage leaf extract, but this is not as effective as caterpillar beta-glucosidase in eliciting the volatile production. Caterpillars that feed on a beta-glucosidase-free diet secrete the enzyme, and their regurgitant is an effective elicitor of the plant response. These findings show that beta-glucosidase is a P. brassicae-secreted elicitor of the defense response of cabbage plants to herbivore injury, inducing the emission of volatiles that are used by parasitoids of the herbivore to locate their victims

An extracellular β-glucosidase was purified 154-fold to electrophoretic homogeneity from the brown-rot basidiomycete Fomitopsis palustris grown on 2.0% microcrystalline cellulose. SDS-polyacrylamide gel electrophoresis gel gave a single protein band and the molecular mass of purified enzyme was estimated to be approximately 138 kDa. The amino acid sequences of the proteolytic fragments determined by nano-LC-MS/MS suggested that the protein has high homology with fungal β-glucosidases that belong to glycosyl hydrolase family 3. The K∧ms for p-nitorophenyl-β-D-glucoside (p-NPG) and cellobiose hydrolyses were 0.117 and 4.81 mM, and the K∧cat values were 721 and 101.8 per see, respectively. The enzyme was competitively inhibited by both glucose (K∧i= 0.35 mM) and gluconolactone (K∧i= 0.008 mM), when p-NPG was used as substrate. The optimal activity of the purified β-glucosidase was observed at pH 4.5 and 70℃. The F. palustris protein exhibited half-lives of 97 h at 55℃ and 15 h at 65℃, indicating some degree of thermostability. The enzyme has high activity against p-NPG and cellobiose but has very little or no activity against p-nitrophenyl-β-lactoside, p-nitrophenyl-β-xyloside, p-nitrophenyl-α-arabinofuranoside, xylan, and carboxymethyl cellulose. Thus, our results revealed that the β-glucosidase from F. palustris can be classified as an aryl-β-glucosidase with cellobiase activity.

Human intestinal maltase (HMA) is an alpha-glucosidase responsible for the hydrolysis of α-1,4-linkages from the non-reducing end of malto-oligosaccharides. HMA has become an important target in the treatment of type-2 diabetes. In this study, epigallocatechin gallate (EGCG) and EGCG glucoside (EGCG-G1) were identified as inhibitors of HMA by an in vitro assay with IC∧50 of 20 ± 1.0 and 31.5 ± 1.0 μM, respectively. A Lineweaver-Burk plot confirmed that EGCG and EGCG-G1 were competitive inhibitors of maltose substrate against HMA and inhibition kinetic constants (K∧i) calculated from a Dixon plot were 5.93 ± 0.26 and 7.88 ± 0.57 μM, respectively. Both EGCG and EGCG-G1 bound to the active site of HMA with numerous hydrophobic and hydrogen bond interactions.

We report the cloning of a novel β-glucosidase-like gene by function-based screening of a metagenomic library from uncultured soil microorganisms. The gene was named bgl1C and has an open reading frame of 1,443 base pairs. It encodes a 481 amino acid polypeptide with a predicted molecular mass of about 57.8 kDa. The deduced amino acid sequence did not show any homology with known β-glucosidases. The putative β-glucosidase gene was subcloned into the pETBlue-2 vector and overexpressed in E. coli Tuner (DE3) pLacI; the recombinant protein was purified to homogeneity. Functional characterization with a high performance liquid chromatography method demonstrated that the recombinant Bgl1C protein hydrolyzed D-glucosyl-β-(l-4)-D-glucose to glucose. The maximum activity for Bgl1C protein occurred at pH 8.0 and 42℃ using p-nitrophenyl-β-D-glucoside as the substrate. A CaCl₂ concentration of 1 mM was required for optimal activity. The putative β-glucosidase had an apparent K∧m value of 0.19 mM, a V∧max value of 4.75 U/mg and a k∧cat value of 316.7/min under the optimal reaction conditions. The biochemical characterization of Bgl1C has enlarged our understanding of the novel enzymes that can be isolated from the soil metagenome.

Resumen. Se evaluaron las actividades enzimáticas (ureasa, proteasa, fosfatasa ácida y alcalina, fosfodiesterasa, b-glucosidasa y arilsulfatasa) en consorcios bacterianos (Bacillus subtilis, Brevundimonas diminuta, Flavimonas oryzihabitants) de suelos bajo cultivo de papa variedad Parda Pastusa, con manejo convencional de aplicación de agroinsumos (PCA) y en suelos bajo pastizal sin aplicación de agroinsumos (PSA), en fincas de tres localidades del departamento de Cundinamarca (Tausa, Villapinzón y Zipaquirá), Colombia. Se encontraron efectos por la aplicación de insumos de síntesis química y el tipo de uso del suelo, sobre las actividades enzimáticas; sin embargo, estos fueron diferentes para cada una de las enzimas y localidades. Para el municipio de Villapinzón la actividad de ureasa, fosfatasa ácida, fosfodiesterasa y b-glucosidasa, fue mayor en las muestras PCA con respecto a las PSA en un 89, 71, 67 y 75% respectivamente; para el municipio de Zipaquirá se presentó la misma tendencia en la actividad ureasa, b-glucosidasa y arilsulfatasa con un 50, 71 y 68% respectivamente; finalmente en el municipio de Tausa se mantuvo el mismo comportamiento para la actividad de proteasa, fosfatasa ácida, fosfatasa alcalina, fosfodiesterasa, b-glucosidasa, con un 55, 20, 75, 82 y 87% de mayor actividad en las muestras PCA en relación con las de PSA.Abstract. Enzyme activities were evaluated (urease, protease, acid phosphatase and alkaline phosphodiesterase, b-glucosidase and arylsulfatase) in bacterial consortia (Bacillus subtilis, Brevundimonas diminuta, Flavimonas oryzihabitants) from either soil with potato cropping under conventional management with the application of agrochemicals (PWA) or grassland soils without the use of agrochemicals (GNA) on farms of three municipalities (Tausa, Villapinzón and Zipaquirá) in the department of Cundinamarca, Colombia. The type of land use and the location affected the tested enzymatic activities. In the municipality of Villapinzón urease, acid phosphatase, phosphodiesterase and b-glucosidase activity were higher in PWA than GNA by 89, 71, 67 and 75% respectively. The municipality of Zipaquirá presented the same trend in urease, b-glucosidase and arylsulfatase with higher activity in PWA than GNA by 50, 71 and 68% respectively. Finally in Tausa, the same behavior was found for protease, acid phosphatase, alkaline phosphatase, phosphodiesterase and b-glucosidase with 55, 20, 75, 82 and 87% higher activity in PWA than GNA.

A potential fungal strain producing extracellular β-glucosidase enzyme was isolated from sea water and identified as Aspergillus sydowii BTMFS 55 by a molecular approach based on 28S rDNA sequence homology which showed 93% identity with already reported sequences of Aspergillus sydowii in the GenBank. A sequential optimization strategy was used to enhance the production of β-glucosidase under solid state fermentation (SSF) with wheat bran (WB) as the growth medium. The two-level Plackett-Burman (PB) design was implemented to screen medium components that influence β-glucosidase production and among the 11 variables, moisture content, inoculums, and peptone were identified as the most significant factors for β-glucosidase production. The enzyme was purified by (NH₄)₂SO₄ precipitation followed by ion exchange chromatography on DEAE sepharose. The enzyme was a monomeric protein with a molecular weight of ~95 kDa as determined by SDS-PAGE. It was optimally active at pH 5.0 and 50℃. It showed high affinity towards pNPG and enzyme has a K∧m and V∧max of 0.67 mM and 83.3 U/mL, respectively. The enzyme was tolerant to glucose inhibition with a K∧i of 17 mM. Low concentration of alcohols (10%), especially ethanol, could activate the enzyme. A considerable level of ethanol could produce from wheat bran and rice straw after 48 and 24 h, respectively, with the help of Saccharomyces cerevisiae in presence of cellulase and the purified β-glucosidase of Aspergillus sydowii BTMFS 55.