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Sample records for high enzymatic activity

  1. Effect of restricted motion in high temperature on enzymatic activity of the pancreas

    Science.gov (United States)

    Abdusattarov, A.; Smirnova, G. I.

    1980-01-01

    Effects of 30 day hypodynamia coupled with high temperature (35-36 C) on enzymatic activity of the pancreas of male adult rats were studied. The test animals were divided into four groups. Group one served as controls (freedom of movement and a temperature of 25-26 C, considered optimal). The remaining animals were divided into three additional groups: Group two freedom of movement but high temperature (35-36 C); group three hypodynamia but an optimal temperature; group four hypodynamia and 35-36 C. Considerable change in the enzymatic activity in the pancreas of the four groups is observed in three experimental groups (two, three, and four) as compared to the control (group one). The results indicate that adaption of the organism to the thermal factor and restricted movement is accompanied by a change in the enzymatic spectrum of the pancreas. With the combined effect of these two stresses under conditions of the adaption of the organism especially sharp shifts occur in the enzymatic activity.

  2. Immobilization of inorganic pyrophosphatase on nanodiamond particles retaining its high enzymatic activity.

    Science.gov (United States)

    Rodina, Elena V; Valueva, Anastasiya V; Yakovlev, Ruslan Yu; Vorobyeva, Nataliya N; Kulakova, Inna I; Lisichkin, Georgy V; Leonidov, Nikolay B

    2015-12-21

    Nanodiamond (ND) particles are popular platforms for the immobilization of molecular species. In the present research, enzyme Escherichia coli inorganic pyrophosphatase (PPase) was immobilized on detonation ND through covalent or noncovalent bonding and its enzymatic activity was characterized. Factors affecting adsorption of PPase such as ND size and surface chemistry were studied. The obtained material is a submicron size association of ND particles and protein molecules in approximately equal amounts. Both covalently and noncovalently immobilized PPase retains a significant enzymatic activity (up to 95% of its soluble form) as well as thermostability. The obtained hybrid material has a very high enzyme loading capacity (∼1 mg mg(-1)) and may be considered as a promising delivery system of biologically active proteinaceous substances, particularly in the treatment of diseases such as calcium pyrophosphate crystal deposition disease and related pathologies. They can also be used as recoverable heterogeneous catalysts in the traditional uses of PPase.

  3. Heavy metal pollution and soil enzymatic activity

    Energy Technology Data Exchange (ETDEWEB)

    Tyler, G

    1974-01-01

    The activity of hydrolytic soil enzymes was studied on spruce mor, polluted with Cu and Zn from a brass foundry in Sweden. Approximately straight regression lines were obtained between enzymatic activity or respiration rate and log Cu + Zn concentration, with highly significant negative regression coefficients for urease and acid phosphatase activity as well as respiration rate, whereas US -glucosidase activity was not measurably lower at high concentrations of Cu + Zn. 17 references, 5 figures.

  4. Testing the applicability of rapid on-site enzymatic activity detection for surface water monitoring

    Science.gov (United States)

    Stadler, Philipp; Vogl, Wolfgang; Juri, Koschelnik; Markus, Epp; Maximilian, Lackner; Markus, Oismüller; Monika, Kumpan; Peter, Strauss; Regina, Sommer; Gabriela, Ryzinska-Paier; Farnleitner Andreas, H.; Matthias, Zessner

    2015-04-01

    On-site detection of enzymatic activities has been suggested as a rapid surrogate for microbiological pollution monitoring of water resources (e.g. using glucuronidases, galactosidases, esterases). Due to the possible short measuring intervals enzymatic methods have high potential as near-real time water quality monitoring tools. This presentation describes results from a long termed field test. For twelve months, two ColiMinder devices (Vienna Water Monitoring, Austria) for on-site determination of enzymatic activity were tested for stream water monitoring at the experimental catchment HOAL (Hydrological Open Air Laboratory, Center for Water Resource Systems, Vienna University of Technology). The devices were overall able to follow and reflect the diverse hydrological and microbiological conditions of the monitored stream during the test period. Continuous data in high temporal resolution captured the course of enzymatic activity in stream water during diverse rainfall events. The method also proofed sensitive enough to determine diurnal fluctuations of enzymatic activity in stream water during dry periods. The method was able to capture a seasonal trend of enzymatic activity in stream water that matches the results gained from Colilert18 analysis for E. coli and coliform bacteria of monthly grab samples. Furthermore the comparison of ColiMinder data with measurements gained at the same test site with devices using the same method but having different construction design (BACTcontrol, microLAN) showed consistent measuring results. Comparative analysis showed significant differences between measured enzymatic activity (modified fishman units and pmol/min/100ml) and cultivation based analyses (most probable number, colony forming unit). Methods of enzymatic activity measures are capable to detect ideally the enzymatic activity caused by all active target bacteria members, including VBNC (viable but nonculturable) while cultivation based methods cannot detect VBNC

  5. Enzymatic activity of the cellulolytic complex produced by trichoderma reesei. Enzymatic hydrolysis of cellulose

    International Nuclear Information System (INIS)

    Alfonsel Jaen, M.; Negro, M.J.; Saez, R.; Martin Moreno, C.

    1986-01-01

    The enzymatic activity characterization of the cellulolytic complex obtained from Trichoderma reese QM 9414 and the influence of the enzymatic hydrolysis conditions on the hydrolysis yield are studied. Pure cellulose and native or alkali pretreated biomass from Onopordum nervosum have been used as substrates. The values of pH, temperature, substrate concentration and enzyme-substrate ratio for the optimum activity of that complex, evaluated as glucose and reducing sugars productions, have been selected. Previous studies on enzymatic hydrolysis of O. nervosum have shown a remarkable effect of the alkaline pretreatments on the final hydrolysis yield. (author). 10 figs.; 10 refs

  6. Enzymatic activity of the cellulolytic complex produced by Trichoderma reesei. Enzymatic hydrolysis of cellulose

    International Nuclear Information System (INIS)

    Alfonsel J, M.; Negro A, M. J.; Saez A, R.; Martin M, C.

    1986-01-01

    The enzymatic activity characterization of the cellulolytic complex obtained from Trichoderma reesei QM 9414 and the influence of the enzymatic hydrolysis conditions on the hydrolysis yield are studied. Pure cellulose and native or alkali pretreated biomass Onopordum nervosum have been used as substrates. The values of pH, temperature, substrate concentration and enzyme-substrate ratio for the optimum activity of that complex, evaluated as glucose and reducing sugars production, have been selected. Previous studies on enzymatic hydrolysis of 0. nervosum have shown a remarkable effect of the alkaline pretreatments on the final hydrolysis yield. (Author) 10 refs

  7. Impact of potato cultivation and cattle farming on physicochemical parameters and enzymatic activities of Neotropical high Andean Páramo ecosystem soils.

    Science.gov (United States)

    Avellaneda-Torres, Lizeth Manuela; León Sicard, Tomás Enrique; Torres Rojas, Esperanza

    2018-08-01

    The Andean Páramos are high mountain ecosystems whose soils are essential for the management of South American water resources, but research on anthropic impacts to these soils is currently minimal and insufficient. The objective of this study was to evaluate the impacts of potato (Solanum tuberosum) cultivation and livestock on the physicochemical parameters and enzymatic activities that determine the soil quality of the Neotropical high Andean Páramo ecosystem in the Nevados National Natural Park (Nevados NNP) in Colombia. It was hypothesised that sites with potato crops and livestock farming would exhibit significant changes in soil physicochemical parameters and enzymatic activities compared with Páramo sites that have been conserved without agriculture. Samples were collected from soils under potato cultivation, livestock and Páramo (subject to the lowest degree of human intervention possible), on three farms in the El Bosque District at three different altitudes (Buenos Aires, El Edén and La Secreta) during two seasons (dry and rainy). The results showed that none of the physical parameters under study presented statistically significant differences due to the type of use (livestock, potato crop or Páramo), season of sampling (dry or rainy season) or altitude (different farms). The chemical parameters that statistically significantly differed due to land use were organic carbon, cation exchange capacity, calcium, potassium, and ammonium and those that showed statistically significant differences associated with the sampling timing were organic carbon, nitrogen, cation exchange capacity, total carbon, C/N and nitrate. Additionally, there were differences in organic carbon due to the altitude of the farms. With respect to enzymatic activities, those of β-glucosidase, phosphodiesterase and urease significantly decreased in soils under potato cultivation and livestock relative to those of Páramo, but those of acid phosphatase and protease increased

  8. Enzymatic activity of fungi isolated from crops

    Directory of Open Access Journals (Sweden)

    Wioletta A. Żukiewicz-Sobczak

    2016-12-01

    Full Text Available Aim: To detect and assess the activity of extracellular hydrolytic enzymes and to find differences in enzymograms between fungi isolated from wheat and rye samples and grown on Czapek-Dox Broth and Sabouraud Dextrose Broth enriched with cereal (wheat or rye. Isolated strains were also classified in the scale of biosafety levels (BSL. Material and methods: The study used 23 strains of fungi cultured from samples of wheat and rye (grain, grain dust obtained during threshing and soil collected in the Lublin region (eastern Poland. API ZYM test (bioMérieux was carried out according to the manufacturer’s instructions. Classification of BSL (Biosafety levels was based on the current literature. Results : High enzymatic activity was found in strains cultured in media containing 1% of wheat grain ( Bipolaris holmi, Penicillium decumbens and with an addition of 1% of rye grain ( Cladosporium herbarum, Aspergillus versicolor, Alternaria alternata . The total number of enzymes varied depending on the type of media, and in most cases it was higher in the culture where an addition of cereal grains was used. Conclusions : Isolated strains of fungi reveal differences in the profiles of the enzyme assay. It can be assumed that the substrate enriched in grains stimulate the higher activity of mold enzymes. Key words: enzymatic activity, mold fungi, zymogram, biohazards.

  9. Enzymatic Hydrolysis of Oleuropein from Olea europea (Olive Leaf Extract and Antioxidant Activities

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    Jiao-Jiao Yuan

    2015-02-01

    Full Text Available Oleuropein (OE, the main polyphenol in olive leaf extract, is likely to decompose into hydroxytyrosol (HT and elenolic acid under the action of light, acid, base, high temperature. In the enzymatic process, the content of OE in olive leaf extract and enzyme are key factors that affect the yield of HT. A selective enzyme was screened from among 10 enzymes with a high OE degradation rate. A single factor (pH, temperature, time, enzyme quantity optimization process and a Box-Behnken design were studied for the enzymatic hydrolysis of 81.04% OE olive leaf extract. Additionally, enzymatic hydrolysis results with different substrates (38.6% and 81.04% OE were compared and the DPPH antioxidant properties were also evaluated. The result showed that the performance of hydrolysis treatments was best using hemicellulase as a bio-catalyst, and the high purity of OE in olive extract was beneficial to biotransform OE into HT. The optimal enzymatic conditions for achieving a maximal yield of HT content obtained by the regression were as follows: pH 5, temperature 55 °C and enzyme quantity 55 mg. The experimental result was 11.31% ± 0.15%, and the degradation rate of OE was 98.54%. From the present investigation of the antioxidant activity determined by the DPPH method, the phenol content and radical scavenging effect were both decreased after enzymatic hydrolysis by hemicellulase. However, a high antioxidant activity of the ethyl acetate extract enzymatic hydrolysate (IC50 = 41.82 μg/mL was demonstated. The results presented in this work suggested that hemicellulase has promising and attractive properties for industrial production of HT, and indicated that HT might be a valuable biological component for use in pharmaceutical products and functional foods.

  10. Effect of aflatoxin B1 on growth and enzymatic activity of a native strain of Bacillus sp

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    Alex Sáez Vega

    2004-01-01

    Full Text Available The effect of different aflatoxin B1 (AFAB1 concentrations on alkaline protease growth and enzymatic activity was evaluated; a native strain of alkalophilic Bacillus sp cultivated in CSL (Corn Steep Liquor was used. It was found that the effect of AFAB1 on the strain inhibited its growth and enzymatic activity to 1 ppm, showing that the strain is highly sensible to AFAB1, meaning that medium obtained f rom Colombian corn contaminated with this mycotoxin cannot be easily used. Concentrations less than 0.1 ppm did not affect growth and enzymatic activity. Key words: Bacillus, aflatoxin, alkaline proteases.

  11. Detection of extracellular enzymatic activity in microorganisms ...

    African Journals Online (AJOL)

    Detection of extracellular enzymatic activity in microorganisms isolated from waste vegetable oil contaminated soil using plate methodologies. Eugenia G. Ortiz Lechuga, Isela Quintero Zapata, Katiushka Arévalo Niño ...

  12. Detection of extracellular enzymatic activity in microorganisms ...

    African Journals Online (AJOL)

    sunny t

    2015-09-18

    Sep 18, 2015 ... microorganisms with all three enzymatic activities, thereby establishing these techniques as ... supplemented at 1% with vegetable oils, including olive (OLI) ..... cepacia lipase for biodiesel fuel production from soybean oil.

  13. Enzymatic hydrolysis of biomass at high-solids loadings – A review

    International Nuclear Information System (INIS)

    Modenbach, Alicia A.; Nokes, Sue E.

    2013-01-01

    Enzymatic hydrolysis is the unit operation in the lignocellulose conversion process that utilizes enzymes to depolymerize lignocellulosic biomass. The saccharide components released are the feedstock for fermentation. When performed at high-solids loadings (≥15% solids, w/w), enzymatic hydrolysis potentially offers many advantages over conversions performed at low- or moderate-solids loadings, including increased sugar and ethanol concentrations and decreased capital and operating costs. The goal of this review is to provide a consolidated source of information on studies using high-solids loadings in enzymatic hydrolysis. Included in this review is a brief discussion of the limitations, such as a lack of available water, difficulty with mixing and handling, insufficient mass and heat transfer, and increased concentration of inhibitors, associated with the use of high solids, as well as descriptions and findings of studies that performed enzymatic hydrolysis at high-solids loadings. Reactors designed and/or equipped for improved handling of high-solids slurries are also discussed. Lastly, this review includes a brief discussion of some of the operations that have successfully scaled-up and implemented high-solids enzymatic hydrolysis at pilot- and demonstration-scale facilities. -- Highlights: •High solids enzymatic hydrolysis needed for conversion process to be cost-effective. •Limitations must be addressed before benefits of high-solid loadings fully realized. •Some success with high-solids loadings at pilot and demonstration scale

  14. Variations in Enzymatic Activities of Shoots and Roots as an Indicator for Irradiated Seeds

    International Nuclear Information System (INIS)

    Abdelbbaary, N.A.; Elagamay, M.R.

    2005-01-01

    Germinated seedlings from oil seeds (sesame and sunflower) and legumes (Trigonella, Haricot, broad bean and cow pea) were irradiated with gamma rays at doses of 0, 0.2, 0.4, 0.8 and 1 kGy and the data were collected from shoots and roots. Enzymatic activities appeared to be correlated with gamma irradiation dose. The enzymatic activities of irradiated seeds understudy were significantly higher than controls. The peroxidase activities were nearly similar in both roots and shoots, while acid phosphatase activities in roots were higher than in shoots. Also protein contents were higher in roots. The peroxidase and acid phosphatase specific activities in roots were similar. Shoots peroxidase enzymatic activity increased with increased gamma doses. The seedling under study showed two different levels of peroxidase activity, higher as sesame, Trigonella and Sunflower, and lower such as all other legumes understudy. Similar tendency have been also noticed in roots-enzymatic activity, positive correlation between gamma doses treatment and peroxidase enzymatic activity, again two groups higher activity cow pea, broad bean, bean and Trigonella lower such as sesame, such as sesame, sunflower and haircut

  15. ASPECTS CONCERNING THE ENZYMATIC ACTIVITY IN SEVERAL THERMOACTINOMYCETE STRAINS

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    Simona Dunca

    2003-08-01

    Full Text Available In the thermoactinomycete strains subjected to examination the values of their recorded enzymatic activities (i.e. α-amy lase, protease, exo-β-1,4 – glucanase, endo -β-1,4 – glucanase and β-glucosidase were lower in the stationary cultures as compared to the stirred ones. The strain Thermomonospora fusca BB255 was found to be highly cellulase- producing and at the same time able to synthesize α-amy lases and proteases.

  16. Enzymatic Activity of Free-Prostate-Specific Antigen (f-PSA) Is Not Required for Some of its Physiological Activities

    Science.gov (United States)

    Chadha, Kailash C.; Nair, Bindukumar B.; Chakravarthi, Srikant; Zhou, Rita; Godoy, Alejandro; Mohler, James L.; Aalinkeel, Ravikumar; Schwartz, Stanley A.; Smith, Gary J.

    2015-01-01

    BACKGROUND Prostate specific antigen (PSA) is a well known biomarker for early diagnosis and management of prostate cancer. Furthermore, PSA has been documented to have anti-angiogenic and anti-tumorigenic activities in both in vitro and in vivo studies. However, little is known about the molecular mechanism(s) involved in regulation of these processes, in particular the role of the serine-protease enzymatic activity of PSA. METHODS Enzymatic activity of PSA isolated directly from seminal plasma was inhibited specifically (>95%) by incubation with zinc2+. Human umbilical vein endothelial cells (HUVEC) were utilized to compare/contrast the physiological effects of enzymatically active versus inactive PSA. RESULTS Equimolar concentrations of enzymatically active PSA and PSA enzymatically inactivated by incubation with Zn2+ had similar physiological effects on HUVEC, including inhibiting the gene expression of pro-angiogenic growth factors, like VEGF and bFGF, and up-regulation of expression of the anti-angiogenic growth factor IFN-γ; suppression of mRNA expression for markers of blood vessel development, like FAK, FLT, KDR, TWIST-1; P-38; inhibition of endothelial tube formation in the in vitro Matrigel Tube Formation Assay; and inhibition of endothelial cell invasion and migration properties. DISCUSSION Our data provides compelling evidence that the transcriptional regulatory and the anti-angiogenic activities of human PSA are independent of the innate enzymatic activity PMID:21446007

  17. Biosensing strategies based on enzymatic reactions and nanoparticles.

    Science.gov (United States)

    Díez-Buitrago, Beatriz; Briz, Nerea; Liz-Marzán, Luis M; Pavlov, Valeri

    2018-04-16

    Enzymes are pivotal elements in bioanalysis due to their specificity and extremely high catalytic activity. The sensitivity of bioanalytical assays depends mainly on the capacity of an observer to detect the product(s) of a biocatalytic reaction. Both natural and artificial compounds have been traditionally used to evaluate enzymatic activities. The drawbacks of chromogenic and fluorogenic organic enzymatic substrates are their high cost and low stability, resulting in high background signals. We review here state of the art assays in the detection of enzymatic activities using recent advances in nanoscience. Novel methods based on the use of nanoparticles lead to increased sensitivity and decreased costs for bioanalysis based on enzymes as recognition elements and signal amplifiers in Enzyme-Linked Immunosorbent Assays (ELISA). Novel approaches toward the detection of enzymatic activities are based on biocatalytic synthesis, modulation, etching, and aggregation of nanoparticles under physiological conditions.

  18. Enzymatic activity measured by microcalorimetry in soil amended with organic residues

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    Karina Cenciani

    2011-08-01

    Full Text Available Enzymatic activity is an important property for soil quality evaluation. Two sequences of experiments were carried out in order to evaluate the enzymatic activity in a soil (Rhodic Eutrudox amended with cattle manure, earthworm casts, or sewage sludges from the municipalities of Barueri and Franca. The activity of commercial enzymes was measured by microcalorimetry in the same soil samples after sterilization. In the first experiment, the enzyme activities of cellulase, protease, and urease were determined in the soil samples during a three month period. In the second sequence of experiments, the thermal effect of the commercial enzymes cellulase, protease, and urease on sterilized soil samples under the same tretaments was monitored for a period of 46 days. The experimental design was randomized and arranged as factorial scheme in five treatments x seven samplings with five replications. The treatment effects were statistically evaluated by one-way analysis of variance. Tukey´s test was used to compare means at p < 0.05. The presence of different sources of organic residues increased the enzymatic activity in the sampling period. Cattle manure induced the highest enzymatic activity, followed by municipal sewage sludge, whereas earthworm casts induced the lowest activity, but differed from control treatment. The thermal effect on the enzyme activity of commercial cellulase, protease, and urease showed a variety of time peaks. These values probably oscillated due to soil physical-chemical factors affecting the enzyme activity on the residues.

  19. Rapid estimation of compost enzymatic activity by spectral analysis method combined with machine learning.

    Science.gov (United States)

    Chakraborty, Somsubhra; Das, Bhabani S; Ali, Md Nasim; Li, Bin; Sarathjith, M C; Majumdar, K; Ray, D P

    2014-03-01

    The aim of this study was to investigate the feasibility of using visible near-infrared (VisNIR) diffuse reflectance spectroscopy (DRS) as an easy, inexpensive, and rapid method to predict compost enzymatic activity, which traditionally measured by fluorescein diacetate hydrolysis (FDA-HR) assay. Compost samples representative of five different compost facilities were scanned by DRS, and the raw reflectance spectra were preprocessed using seven spectral transformations for predicting compost FDA-HR with six multivariate algorithms. Although principal component analysis for all spectral pretreatments satisfactorily identified the clusters by compost types, it could not separate different FDA contents. Furthermore, the artificial neural network multilayer perceptron (residual prediction deviation=3.2, validation r(2)=0.91 and RMSE=13.38 μg g(-1) h(-1)) outperformed other multivariate models to capture the highly non-linear relationships between compost enzymatic activity and VisNIR reflectance spectra after Savitzky-Golay first derivative pretreatment. This work demonstrates the efficiency of VisNIR DRS for predicting compost enzymatic as well as microbial activity. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Antimicrobial and enzymatic activity of anemophilous fungi of a public university in Brazil

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    LAUREANA V. SOBRAL

    2017-10-01

    Full Text Available ABSTRACT To the fungal microbiota the UFPE and biotechnological potential enzymatic and antimicrobial production. Air conditioned environments were sampled using a passive sedimentation technique, the air I ratio and the presence of aflatoxigenic strains evaluated for ANVISA. Icelles were to determine the enzymatic activity of lipase, amylase and protease metabolic liquids to determine antimicrobial activity. Diversity was observed in all CAV environments, CFU/m3 ranged from 14 to 290 and I/E ratio from 0.1 to 1.5. The of the fungal genera were: Aspergillus (50%, Penicillium (21%, Talaromyces (14%, Curvularia and Paecilomyces (7% each. Aspergillus sydowii (Bainier & Sartory Thom & Church presented enzymatic activity and the Talaromyces purpureogenus Samson, Yilmaz, Houbraken, Spierenb., Seifert, Peterson, Varga & Frisvad presented antibacterial activity against all bacteria that all environments present fungal species biodiversity no toxigenic or pathogenic fungi were found, according to ANVISA legislation for conditioned environments and airborne filamentous fungi present potential for enzymatic and antimicrobial activity.

  1. The variations of enzymatic activity of pepsin preparation by γ-irradiation

    International Nuclear Information System (INIS)

    Kimura, Syojiro; Taimatsu, Meiko; Kanbashi, Toshitaka; Okamoto, Shinichi; Ohnishi, Tokuhiro.

    1993-01-01

    Effect of γ-irradiation on the enzymatic activity of raw pepsin and some saccharated pepsin preparations were studied in the dose range from 0 to 300 kGy. As a result, the apparent reduction rate of saccharated pepsin preparations is less than of raw pepsin. K values of raw and saccharated pepsins were 0.014 and 0.0040-0.0061, and G values of raw and saccharated pepsins were 3.98 and 1.13-1.73, respectively. The lower K and G values of saccharated pepsin than those of raw pepsin seem to be due to radiolytic products of lactose in the preparations as an excipient. Retention rates of enzymatic activity of irradiated preparations at the dose of 25 kGy, which is a complete sterilization dose of pharmaceutical materials, were estimated to be 83% for raw pepsin, and 86% and 93% for saccharated pepsin preparations. At the dose of 10 kGy suggested for food irradiation the retention rates were more than 93% for all pepsins. Therefore, this method is applicable considering the stability of the enzymatic activity after irradiation in the proper range of dose. However, it is necessary to consider the fact that radiolytic products of lactose affect the measurement of enzymatic activity. (author)

  2. The effects of xylitol and sorbitol on lysozyme- and peroxidase-related enzymatic and candidacidal activities.

    Science.gov (United States)

    Kim, Bum-Soo; Chang, Ji-Youn; Kim, Yoon-Young; Kho, Hong-Seop

    2015-07-01

    To investigate whether xylitol and sorbitol affect enzymatic and candidacidal activities of lysozyme, the peroxidase system, and the glucose oxidase-mediated peroxidase system. Xylitol and sorbitol were added to hen egg-white lysozyme, bovine lactoperoxidase, glucose oxidase-mediated peroxidase, and whole saliva in solution and on hydroxyapatite surfaces. The enzymatic activities of lysozyme, peroxidase, and glucose oxidase-mediated peroxidase were determined by the turbidimetric method, the NbsSCN assay, and production of oxidized o-dianisidine, respectively. Candidacidal activities were determined by comparing colony forming units using Candida albicans ATCC strains 10231, 11006, and 18804. While xylitol and sorbitol did not affect the enzymatic activity of hen egg-white lysozyme both in solution and on hydroxyapatite surfaces, they did inhibit the enzymatic activity of salivary lysozyme significantly in solution, but not on the surfaces. Xylitol and sorbitol enhanced the enzymatic activities of both bovine lactoperoxidase and salivary peroxidase significantly in a dose-dependent manner in solution, but not on the surfaces. Sorbitol, but not xylitol, inhibited the enzymatic activity of glucose oxidase-mediated peroxidase significantly. Both xylitol and sorbitol did not affect candidacidal activities of hen egg-white lysozyme, the bovine lactoperoxidase system, or the glucose oxidase-mediated bovine lactoperoxidase system. Xylitol and sorbitol inhibited salivary lysozyme activity, but enhanced both bovine lactoperoxidase and salivary peroxidase activities significantly in solution. Xylitol and sorbitol did not augment lysozyme- and peroxidase-related candidacidal activities. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Enzymatic browning control in cut apples (Red delicious through a system of active packaging

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    Felipe Jadán Piedra

    2017-03-01

    Full Text Available Enzymatic browning is one of the most relevant mechanisms of deterioration that take place in fresh-cut fruit and vegetables, as a consequence of the activity of the polyphenol oxidase enzyme on the phenolic compounds release after cellular lysis . This work is focused on the reduction of these enzymatic activity by an active packaging technology, which make use of a material that incorporates antioxidant active agents. Thus, films of ethylene-vynil alcohol copolymer (EVOH containing a typical food antioxidant, such as ascorbic acid and a polyphenol oxidase-inhibiting agent, the 4-hexylresorcinol have been developed and used to wrap apple slices. The evolution of color, the enzymatic activity and the kinetic of agents release to food simulants were monitored. The results showed an improvement of apple slice color stability and a reduction of the enzymatic activity. The film with 10 % of agents in 3/1 ratio (4-hexylresorcinol/ascorbic acid provided the best results.

  4. First results on enzymatic activities in two salt marsh soils under different hydromorphic level and vegetation

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    Carmen Trasar-Cepeda

    2015-12-01

    Full Text Available Salt-marsh soils are soils characterized by non-permanent hydric saturation that, depending on factors like duration of submersion periods, are dominated by different salt-tolerant plant species. The composition of microbial communities is an essential component in trophic dynamics and biogeochemical processes in salt marshes, and determines the level of enzymatic activities, which catalyze the conversion of complex molecules into simpler ones. Despite of this, the enzymatic activities in marsh-soils has not yet been investigated. The aim of this study was to analyze the enzymatic activities in two soil profiles of marsh-soils under different water saturation level and dominated by different plant species [Juncus maritimus Lam and Spartina maritima (Curtis Fernald (Sp]. In both soils, the enzymatic activities were much lower than the levels typically found in terrestrial ecosystems. The enzymatic activities were measured both in air-dried and in re-moistened and incubated soil samples. In air-dried samples, the enzymatic activities were higher in Juncus than in Spartina soil and tended to decrease with depth, being sharper the decrease in Juncus than in Spartina soil. Re-moistened and pre-incubated soils showed a general increase in all the enzymatic activities and throughout the whole soil profile, especially in Spartina soils. Hydrolase activities showed a strong and positive relationship with organic matter content both in air-dried and in re-moistened soil samples, higher in these latter. In general, oxidoreductase activities only showed this relationship in re-moistened soil samples. More studies, preferably using freshly collected soil samples, are needed to understand the relationship between enzymatic activities and these environmental conditions.

  5. Ebselen inhibits QSOX1 enzymatic activity and suppresses invasion of pancreatic and renal cancer cell lines.

    Science.gov (United States)

    Hanavan, Paul D; Borges, Chad R; Katchman, Benjamin A; Faigel, Douglas O; Ho, Thai H; Ma, Chen-Ting; Sergienko, Eduard A; Meurice, Nathalie; Petit, Joachim L; Lake, Douglas F

    2015-07-30

    Quiescin sulfhydryl oxidase 1 (QSOX1) is a highly conserved disulfide bond-generating enzyme that is overexpressed in diverse tumor types. Its enzymatic activity promotes the growth and invasion of tumor cells and alters extracellular matrix composition. In a nude mouse-human tumor xenograft model, tumors containing shRNA for QSOX1 grew significantly more slowly than controls, suggesting that QSOX1 supports a proliferative phenotype in vivo. High throughput screening experiments identified ebselen as an in vitro inhibitor of QSOX1 enzymatic activity. Ebselen treatment of pancreatic and renal cancer cell lines stalled tumor growth and inhibited invasion through Matrigel in vitro. Daily oral treatment with ebselen resulted in a 58% reduction in tumor growth in mice bearing human pancreatic tumor xenografts compared to controls. Mass spectrometric analysis of ebselen-treated QSOX1 mechanistically revealed that C165 and C237 of QSOX1 covalently bound to ebselen. This report details the anti-neoplastic properties of ebselen in pancreatic and renal cancer cell lines. The results here offer a "proof-of-principle" that enzymatic inhibition of QSOX1 may have clinical relevancy.

  6. High volumetric power density, non-enzymatic, glucose fuel cells.

    Science.gov (United States)

    Oncescu, Vlad; Erickson, David

    2013-01-01

    The development of new implantable medical devices has been limited in the past by slow advances in lithium battery technology. Non-enzymatic glucose fuel cells are promising replacement candidates for lithium batteries because of good long-term stability and adequate power density. The devices developed to date however use an "oxygen depletion design" whereby the electrodes are stacked on top of each other leading to low volumetric power density and complicated fabrication protocols. Here we have developed a novel single-layer fuel cell with good performance (2 μW cm⁻²) and stability that can be integrated directly as a coating layer on large implantable devices, or stacked to obtain a high volumetric power density (over 16 μW cm⁻³). This represents the first demonstration of a low volume non-enzymatic fuel cell stack with high power density, greatly increasing the range of applications for non-enzymatic glucose fuel cells.

  7. Enzymatic activities of Azotobacter chroococcum and survival in ...

    African Journals Online (AJOL)

    Enzymatic activities of Azotobacter chroococcum and survival in schloropyrifos amended sterile and non-sterile. M Shukla, V Kumar, RL Thakur, N Narula. Abstract. No Abstract. Cameroon Journal of Experimental Biology Vol. 2 (2) 2006: pp. 88-94. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for ...

  8. Impact of herbaceous vegetation on the enzymatic activity of coal mining wastes

    Energy Technology Data Exchange (ETDEWEB)

    Osmanczyk, D

    1980-01-01

    Differences in the enzymatic activity of reclaimed and crude dump wastes after coal mining were investigated. Due to the increased activity of six investigated enzymes (dehydrogenase, catalase, saccharase, BETA-glucosidase, urease and asparaginase), a favourable impact of herbaceous vegetation on the biological activation of the breeding-ground was noticed. Particularly in the case of sacharase and BETA-glucosidase, an increase of the enzymatic activity at a rate of several times or even more than ten times speaks not only for an adequate increase of the metabolic rate of carbohydrates but also for specific properties of the habitat which favours an adsorption of these enzymes. (6 refs.) (In Polish)

  9. Site-Specific Bioconjugation of an Organometallic Electron Mediator to an Enzyme with Retained Photocatalytic Cofactor Regenerating Capacity and Enzymatic Activity

    Directory of Open Access Journals (Sweden)

    Sung In Lim

    2015-04-01

    Full Text Available Photosynthesis consists of a series of reactions catalyzed by redox enzymes to synthesize carbohydrates using solar energy. In order to take the advantage of solar energy, many researchers have investigated artificial photosynthesis systems mimicking the natural photosynthetic enzymatic redox reactions. These redox reactions usually require cofactors, which due to their high cost become a key issue when constructing an artificial photosynthesis system. Combining a photosensitizer and an Rh-based electron mediator (RhM has been shown to photocatalytically regenerate cofactors. However, maintaining the high concentration of cofactors available for efficient enzymatic reactions requires a high concentration of the expensive RhM; making this process cost prohibitive. We hypothesized that conjugation of an electron mediator to a redox enzyme will reduce the amount of electron mediators necessary for efficient enzymatic reactions. This is due to photocatalytically regenerated NAD(PH being readily available to a redox enzyme, when the local NAD(PH concentration near the enzyme becomes higher. However, conventional random conjugation of RhM to a redox enzyme will likely lead to a substantial loss of cofactor regenerating capacity and enzymatic activity. In order to avoid this issue, we investigated whether bioconjugation of RhM to a permissive site of a redox enzyme retains cofactor regenerating capacity and enzymatic activity. As a model system, a RhM was conjugated to a redox enzyme, formate dehydrogenase obtained from Thiobacillus sp. KNK65MA (TsFDH. A RhM-containing azide group was site-specifically conjugated to p-azidophenylalanine introduced to a permissive site of TsFDH via a bioorthogonal strain-promoted azide-alkyne cycloaddition and an appropriate linker. The TsFDH-RhM conjugate exhibited retained cofactor regenerating capacity and enzymatic activity.

  10. Plasmin enzymatic activity in the presence of actin

    Directory of Open Access Journals (Sweden)

    Yusova E. I.

    2015-10-01

    Full Text Available Aim. To study the changes in the plasmin activity towards substrates with high and low molecular mass in the presence of actin. Methods. The proteins used for this investigation were obtained by affinity chromatography and gel-filtration. The plasmin enzymatic activity was determined by a turbidimetric assay and a chromogenic substrate-based assay. The enzyme linked immunosorbent assay and biotin-avidin-phosphatase system were used to study the interaction of plasminogen and its fragments with actin. Results. It was shown that G-actin causes 1.5-fold decrease in the rate of polymeric fibrin hydrolysis by plasmin and Glu-plasminogen activated by the tissue plasminogen activator. However, actin did not impede plasmin autolysis and had no influence on its amidase activity. We have studied an interaction of biotinylated Glu-plasminogen and its fragments (kringle 1-3, kringle 4 and mini-plasminogen with immobilized G-actin. Glu-plasminogen and kringle 4 had a high affinity towards actin (C50 is 113 and 117 nM correspondingly. Mini-plasminogen and kringe 4 did not bind to actin. A similar affinity of Glu-plasminogen and kringle 1-3 towards actin proves the involvement of the kringle 1-3 lysine-binding sites of the native plasminogen form in the actin interaction. Conclusions. Actin can modulate plasmin specificity towards high molecular mass substrates through its interaction with lysine-binding sites of the enzyme kringle domains. Actin inhibition of the fibrinolytic activity of plasmin is due to its competition with fibrin for thelysine binding sites of plasminogen/plasmin.

  11. New eutectic ionic liquids for lipase activation and enzymatic preparation of biodiesel†

    Science.gov (United States)

    Zhao, Hua; Baker, Gary A.; Holmes, Shaletha

    2012-01-01

    The enzymatic preparation of biodiesel has been hampered by the lack of suitable solvents with desirable properties such as high lipase compatibility, low cost, low viscosity, high biodegradability, and ease of product separation. Recent interest in using ionic liquids (ILs) as advanced reaction media has led to fast reaction rates and high yields in the enzymatic synthesis of biodiesel. However, conventional (i.e., cation–anion paired) ILs based on imidazolium and other quaternary ammonium salts remain too expensive for wide application at industrial scales. In this study, we report on newly-synthesized eutectic ILs derived from choline acetate or choline chloride coupled with biocompatible hydrogen-bond donors, such as glycerol. These eutectic solvents have favorable properties including low viscosity, high biodegradability, and excellent compatibility with Novozym® 435, a commercial immobilized Candida antarctica lipase B. Furthermore, in a model biodiesel synthesis system, we demonstrate high reaction rates for the enzymatic transesterification of Miglyol® oil 812 with methanol, catalyzed by Novozym® 435 in choline acetate/glycerol (1 : 1.5 molar ratio). The high conversion (97%) of the triglyceride obtained within 3 h, under optimal conditions, suggests that these novel eutectic solvents warrant further exploration as potential media in the enzymatic production of biodiesel. PMID:21283901

  12. Malondialdehyde level and some enzymatic activities in subclinical ...

    African Journals Online (AJOL)

    The purpose of this study was to evaluate the changes occurring in milk malondialdehyde (MDA) level and some enzymatic activities as a result of subclinical mastitis (SCM) in dairy cows. A total of 124 milk samples were collected from 124 lactating cows from the same herd in the period between the 2nd week after calving ...

  13. Enzymatic vegetable organic extracts as soil biochemical biostimulants and atrazine extenders.

    Science.gov (United States)

    García-Martínez, Ana María; Tejada, Manuel; Díaz, Ana Isabel; Rodríguez-Morgado, Bruno; Bautista, Juan; Parrado, Juan

    2010-09-08

    The purpose of this study was to gather information on the potential effects of organic biostimulants on soil activity and atrazine biodegradation. Carob germ enzymatic extract (CGEE) and wheat condensed distiller solubles enzymatic extract (WCDS-EE) have been obtained using an enzymatic process; their main organic components are soluble carbohydrates and proteins in the form of peptides and free amino acids. Their application to soil results in high biostimulation, rapidly increased dehydrogenase, phosphatase and glucosidase activities, and an observed atrazine extender capacity due to inhibition of its mineralization. The extender capacity of both extracts is proportional to the protein/carbohydrate ratio content. As a result, these enzymatic extracts are highly microbially available, leading to two independent phenomena, fertility and an atrazine persistence that is linked to increased soil activity.

  14. Differentiation of enzymatic activity of yeasts and yeast-like microorganisms isolated from various environments

    Directory of Open Access Journals (Sweden)

    Elżbieta Bogusławska-Wąs

    2014-08-01

    Full Text Available The aim of study was to determinate enzymatic activity of yeast-like organisms - Candida lipolytica, Rhodotorula rubra, Trichosporon beigelii, Zygosaccharomyces sp. - isolated from the Szczecin Lagoon and herring salads. We have shown that lipolytic activity was higher than protcolytic for every strain tested. The lowest activity level was found out for amylolytic hydrolases. The results also demonstrated that yeast-like organisms isolated from the Szczecin Lagoon revealed much higher average enzymatic activity compared to tbe same species isolated from herring salads, excepting C. lipolytica.

  15. Extracellular enzymatic activities and physiological profiles of yeasts colonizing fruit trees.

    Science.gov (United States)

    Molnárová, Jana; Vadkertiová, Renáta; Stratilová, Eva

    2014-07-01

    Yeasts form a significant and diverse part of the phyllosphere microbiota. Some yeasts that inhabit plants have been found to exhibit extracellular enzymatic activities. The aim of the present study was to investigate the ability of yeasts isolated from leaves, fruits, and blossoms of fruit trees cultivated in Southwest Slovakia to produce extracellular enzymes, and to discover whether the yeasts originating from these plant organs differ from each other in their physiological properties. In total, 92 strains belonging to 29 different species were tested for: extracellular protease, β-glucosidase, lipase, and polygalacturonase activities; fermentation abilities; the assimilation of xylose, saccharose and alcohols (methanol, ethanol, glycerol); and for growth in a medium with 33% glucose. The black yeast Aureobasidium pullulans showed the largest spectrum of activities of all the species tested. Almost 70% of the strains tested demonstrated some enzymatic activity, and more than 90% utilized one of the carbon compounds tested. Intraspecies variations were found for the species of the genera Cryptococcus and Pseudozyma. Interspecies differences of strains exhibiting some enzymatic activities and utilizing alcohols were also noted. The largest proportion of the yeasts exhibited β-glucosidase activity and assimilated alcohols independently of their origin. The highest number of strains positive for all activities tested was found among the yeasts associated with leaves. Yeasts isolated from blossoms assimilated saccharose and D-xylose the most frequently of all the yeasts tested. The majority of the fruit-inhabiting yeasts grew in the medium with higher osmotic pressure. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Quantitation of Na+, K+-atpase Enzymatic Activity in Tissues of the Mammalian Vestibular System

    Science.gov (United States)

    Kerr, T. P.

    1985-01-01

    In order to quantify vestibular Na(+), K(+)-ATPase, a microassay technique was developed which is sufficiently sensitive to measure the enzymatic activity in tissue from a single animal. The assay was used to characterize ATPase in he vestibular apparatus of the Mongolian gerbil. The quantitative procedure employs NPP (5 mM) as synthetic enzyme substrate. The assay relies upon spectrophotometric measurement (410 nm) of nitrophenol (NP) released by enzymatic hydrolysis of the substrate. Product formation in the absence of ouabain reflects both specific (Na(+), K(+)-ATPase) and non-specific (Mg(++)-ATPase) enzymatic activity. By measuring the accumulation of reaction product (NP) at three-minute intervals during the course of incubation, it is found that the overall enzymatic reaction proceeds linearly for at least 45 minutes. It is therefore possible to determine two separate reaction rates from a single set of tissues. Initial results indicate that total activity amounts to 53.3 + or - 11.2 (S.E.M.) nmol/hr/mg dry tissue, of which approximately 20% is ouabain-sensitive.

  17. Methods for determining enzymatic activity comprising heating and agitation of closed volumes

    Science.gov (United States)

    Thompson, David Neil; Henriksen, Emily DeCrescenzo; Reed, David William; Jensen, Jill Renee

    2016-03-15

    Methods for determining thermophilic enzymatic activity include heating a substrate solution in a plurality of closed volumes to a predetermined reaction temperature. Without opening the closed volumes, at least one enzyme is added, substantially simultaneously, to the closed volumes. At the predetermined reaction temperature, the closed volumes are agitated and then the activity of the at least one enzyme is determined. The methods are conducive for characterizing enzymes of high-temperature reactions, with insoluble substrates, with substrates and enzymes that do not readily intermix, and with low volumes of substrate and enzyme. Systems for characterizing the enzymes are also disclosed.

  18. PARTIAL CHARACTERIZATION OF ENZYMATIC ACTIVITIES PRODUCED BY A WILD STRAIN OF A. NIGER

    Directory of Open Access Journals (Sweden)

    María Martos

    2012-12-01

    Full Text Available Aspergillus niger, isolated from decay citrus peels in the province of Misiones, was able to produce pectinases by submerged fermentation. The enzymatic extract exhibited polygalacturonase, pectinesterase and lyase activities. Others enzymes capable of degrading cell wall polymers were also detected in the enzymatic extract such as cellulases and xylanases. Polygalacturonase was an endo-polygalacturonase. The enzyme exhibited a maximal activity at pH range between 4.5 to 5.0, was stable in the pH range from 2.5 to 5.5 and remained unchanged when was incubated at temperatures lower than 50 ºC. The fungi produced three PG isoenzymes. The enzymatic extract was able to clarify apple juice. The results observed make the pectinolytic enzymes produced by A. niger appropriate for future application in fruit juice processing industries.

  19. Enzymatic Activity of Candida spp. from Oral Cavity and Urine in Children with Nephrotic Syndrome.

    Science.gov (United States)

    Olczak-Kowalczyk, Dorota; Roszkowska-Blaim, Maria; Dąbkowska, Maria; Swoboda-Kopeć, Ewa; Gozdowski, Dariusz; Mizerska-Wasiak, Małgorzata; Demkow, Urszula; Pańczyk-Tomaszewska, Małgorzata

    2017-01-01

    Oral colonization with Candida spp. is not synonymous with a systemic active infection. The aim of the study was to evaluate enzymatic activity of Candida strains isolated from the oral cavity in patients with nephrotic syndrome (NS) and to compare it with the activity determined in urine. We studied 32 children with NS and 26 control healthy children. Children with NS were treated with glucocorticosteroids, cyclosporin A, mycophenolate mofetil or azathioprine. In all children, API-ZYM enzymatic tests were performed to evaluate hydrolytic enzymes of Candida isolated from the oral cavity and in urine. Candida spp. were isolated from the oral cavity in 11 patients with NS (34.4%), all receiving immunosuppressive treatment. All strains produced valine arylamidase, 9 alpha-glucosidase (E16), and 9 N-acetyl-beta-glucosaminidase (E18). A positive correlation between the presence of Candida in the oral cavity and E16 and E18 enzymatic activity in both oral cavity and urine was found. A dose of cyclosporin A had an effect on the enzymatic activity (p Candida invasion. The results of this study suggest that oral candida infection should be monitored in children with nephrotic syndrome, particularly those treated with immunosuppressive agents.

  20. Enzymatic activities produced by mixed Saccharomyces and non-Saccharomyces cultures: relationship with wine volatile composition.

    Science.gov (United States)

    Maturano, Yolanda Paola; Assof, Mariela; Fabani, María Paula; Nally, María Cristina; Jofré, Viviana; Rodríguez Assaf, Leticia Anahí; Toro, María Eugenia; Castellanos de Figueroa, Lucía Inés; Vazquez, Fabio

    2015-11-01

    During certain wine fermentation processes, yeasts, and mainly non-Saccharomyces strains, produce and secrete enzymes such as β-glucosidases, proteases, pectinases, xylanases and amylases. The effects of enzyme activity on the aromatic quality of wines during grape juice fermentation, using different co-inoculation strategies of non-Saccharomyces and Saccharomyces cerevisiae yeasts, were assessed in the current study. Three strains with appropriate enological performance and high enzymatic activities, BSc562 (S. cerevisiae), BDv566 (Debaryomyces vanrijiae) and BCs403 (Candida sake), were assayed in pure and mixed Saccharomyces/non-Saccharomyces cultures. β-Glucosidase, pectinase, protease, xylanase and amylase activities were quantified during fermentations. The aromatic profile of pure and mixed cultures was determined at the end of each fermentation. In mixed cultures, non-Saccharomyces species were detected until day 4-5 of the fermentation process, and highest populations were observed in MSD2 (10% S. cerevisiae/90% D. vanrijiae) and MSC1 (1% S. cerevisiae/99% C. sake). According to correlation and multivariate analysis, MSD2 presented the highest concentrations of terpenes and higher alcohols which were associated with pectinase, amylase and xylanase activities. On the other hand, MSC1 high levels of β-glucosidase, proteolytic and xylanolytic activities were correlated to esters and fatty acids. Our study contributes to a better understanding of the effect of enzymatic activities by yeasts on compound transformations that occur during wine fermentation.

  1. Quantitative Collection and Enzymatic Activity of Glucose Oxidase Nanotubes Fabricated by Templated Layer-by-Layer Assembly.

    Science.gov (United States)

    Zhang, Shouwei; Demoustier-Champagne, Sophie; Jonas, Alain M

    2015-08-10

    We report on the fabrication of enzyme nanotubes in nanoporous polycarbonate membranes via the layer-by-layer (LbL) alternate assembly of polyethylenimine (PEI) and glucose oxidase (GOX), followed by dissolution of the sacrificial template in CH2Cl2, collection, and final dispersion in water. An adjuvant-assisted filtration methodology is exploited to extract quantitatively the nanotubes without loss of activity and morphology. Different water-soluble CH2Cl2-insoluble adjuvants are tested for maximal enzyme activity and nanotube stability; whereas NaCl disrupts the tubes by screening electrostatic interactions, the high osmotic pressure created by fructose also contributes to loosening the nanotubular structures. These issues are solved when using neutral, high molar mass dextran. The enzymatic activity of intact free nanotubes in water is then quantitatively compared to membrane-embedded nanotubes, showing that the liberated nanotubes have a higher catalytic activity in proportion to their larger exposed surface. Our study thus discloses a robust and general methodology for the fabrication and quantitative collection of enzymatic nanotubes and shows that LbL assembly provides access to efficient enzyme carriers for use as catalytic swarming agents.

  2. Pressure Modulation of the Enzymatic Activity of Phospholipase A2, A Putative Membrane-Associated Pressure Sensor.

    Science.gov (United States)

    Suladze, Saba; Cinar, Suleyman; Sperlich, Benjamin; Winter, Roland

    2015-10-07

    Phospholipases A2 (PLA2) catalyze the hydrolysis reaction of sn-2 fatty acids of membrane phospholipids and are also involved in receptor signaling and transcriptional pathways. Here, we used pressure modulation of the PLA2 activity and of the membrane's physical-chemical properties to reveal new mechanistic information about the membrane association and subsequent enzymatic reaction of PLA2. Although the effect of high hydrostatic pressure (HHP) on aqueous soluble and integral membrane proteins has been investigated to some extent, its effect on enzymatic reactions operating at the water/lipid interface has not been explored, yet. This study focuses on the effect of HHP on the structure, membrane binding and enzymatic activity of membrane-associated bee venom PLA2, covering a pressure range up to 2 kbar. To this end, high-pressure Fourier-transform infrared and high-pressure stopped-flow fluorescence spectroscopies were applied. The results show that PLA2 binding to model biomembranes is not significantly affected by pressure and occurs in at least two kinetically distinct steps. Followed by fast initial membrane association, structural reorganization of α-helical segments of PLA2 takes place at the lipid water interface. FRET-based activity measurements reveal that pressure has a marked inhibitory effect on the lipid hydrolysis rate, which decreases by 75% upon compression up to 2 kbar. Lipid hydrolysis under extreme environmental conditions, such as those encountered in the deep sea where pressures up to the kbar-level are encountered, is hence markedly affected by HHP, rendering PLA2, next to being a primary osmosensor, a good candidate for a sensitive pressure sensor in vivo.

  3. Antioxidative activities of hydrolysates from edible birds nest using enzymatic hydrolysis

    Science.gov (United States)

    Muhammad, Nurul Nadia; Babji, Abdul Salam; Ayub, Mohd Khan

    2015-09-01

    Edible bird's nest protein hydrolysates (EBN) were prepared via enzymatic hydrolysis to investigate its antioxidant activity. Two types of enzyme (alcalase and papain) were used in this study and EBN had been hydrolysed with different hydrolysis time (30, 60, 90 and 120 min). Antioxidant activities in EBN protein hydrolysate were measured using DPPH, ABTS+ and Reducing Power Assay. From this study, increased hydrolysis time from 30 min to 120 min contributed to higher DH, as shown by alcalase (40.59%) and papain (24.94%). For antioxidant assay, EBN hydrolysed with papain showed higher scavenging activity and reducing power ability compared to alcalase. The highest antioxidant activity for papain was at 120 min hydrolysis time with ABTS (54.245%), DPPH (49.78%) and Reducing Power (0.0680). Meanwhile for alcalase, the highest antioxidant activity was at 30 min hydrolysis time. Even though scavenging activity for EBN protein hydrolysates were high, the reducing power ability was quite low as compared to BHT and ascorbic Acid. This study showed that EBN protein hydrolysate with alcalase and papain treatments potentially exhibit high antioxidant activity which have not been reported before.

  4. Chondroitin sulphate extracted from antler cartilage using high hydrostatic pressure and enzymatic hydrolysis

    Directory of Open Access Journals (Sweden)

    Chong-Tai Kim

    2014-12-01

    Full Text Available Chondroitin sulphate (CS, a major glycosaminoglycan, is an essential component of the extracellular matrix in cartilaginous tissues. Wapiti velvet antlers are a rich source of these molecules. The purpose of the present study was to develop an effective isolation procedure of CS from fresh velvet antlers using a combination of high hydrostatic pressure (100 MPa and enzymatic hydrolysis (papain. High CS extractability (95.1 ± 2.5% of total uronic acid was obtained following incubation (4 h at 50 °C with papain at pH 6.0 in 100 MPa compared to low extractability (19 ± 1.1% in ambient pressure (0.1 MPa. Antler CS fractions were isolated by Sephacryl S-300 chromatography and identified by western blot using an anti-CS monoclonal antibody. The antler CS fraction did not aggregate with hyaluronic acid in CL-2B chromatography and possessed DPPH radical scavenging activity at 78.3 ± 1.5%. The results indicated that high hydrostatic pressure and enzymatic hydrolysis procedure may be a useful tool for the isolation of CS from antler cartilaginous tissues.

  5. Enzymatic activity of the cellulolytic complex produced by Trichoderma reesei. Enzymatic hydrolysis of cellulose; Actividad enzimatica del complejo celulolitico producido por Trichoderma reesei. Hidrolisis enzimatica de la celulosa

    Energy Technology Data Exchange (ETDEWEB)

    Alfonsel, M; Negro, M J; Saez, R; Martin, C

    1986-07-01

    The enzymatic activity characterization of the cellulolytic complex obtained from Trichoderma reesei QM 9414 and the influence of the enzymatic hydrolysis conditions on the hydrolysis yield are studied. Pure cellulose and native or alkali pretreated biomass Onopordum nervosum have been used as substrates. The values of pH, temperature, substrate concentration and enzyme-substrate ratio for the optimum activity of that complex, evaluated as glucose and reducing sugars production, have been selected. Previous studies on enzymatic hydrolysis of 0. nervosum have shown a remarkable effect of the alkaline pretreatments on the final hydrolysis yield. (Author) 10 refs.

  6. Direct electrocatalytic reduction of coenzyme NAD{sup +} to enzymatically-active 1,4-NADH employing an iridium/ruthenium-oxide electrode

    Energy Technology Data Exchange (ETDEWEB)

    Ullah, Nehar, E-mail: nehar.ullah@mail.mcgill.ca; Ali, Irshad; Omanovic, Sasha

    2015-01-15

    A thermally prepared iridium/ruthenium-oxide coating (Ir{sub 0.8}Ru{sub 0.2}-oxide) formed on a titanium substrate was investigated as a possible electrode for direct electrochemical regeneration of enzymatically-active 1,4-NADH from its oxidized form NAD{sup +}, at various electrode potentials, in a batch electrochemical reactor. The coating surface was characterized by ‘cracked mud’ morphology, yielding a high surface roughness. The NADH regeneration results showed that the percentage of enzymatically-active 1,4-NADH present in the product mixture (i.e. recovery) is strongly dependent on the electrode potential, reaching a maximum (88%) at −1.70 V vs. MSE. The relatively high recovery was explained on the basis of availability of adsorbed ‘active’ hydrogen (H{sub ads}) on the Ir/Ru-oxide surface, i.e. on the basis of electrochemical hydrogenation. - Highlights: • Ir{sub 0.8}Ru{sub 0.2}-oxide coating was formed thermally on a Ti substrate. • Electrochemical regeneration of enzymatically-active 1,4-NADH was investigated. • The 1,4-NADH recovery percentage is strongly dependent on the electrode potential. • A highest recovery, 88%, was obtained at −1.70 V vs. MSE. • The NADH regeneration process involved electrochemical hydrogenation.

  7. PARP1 Val762Ala polymorphism reduces enzymatic activity

    International Nuclear Information System (INIS)

    Wang Xiaogan; Wang Zhaoqi; Tong Weimin; Shen Yan

    2007-01-01

    Poly(ADP-ribose) polymerase 1 (PARP1) modifies a variety of nuclear proteins by poly(ADP-ribosyl)ation, and plays diverse roles in molecular and cellular processes. A common PARP1 single nucleotide polymorphism (SNP) at codon 762, resulting in the substitution of alanine (Ala) for valine (Val) in the catalytic domain has been implicated in susceptibility to cancer. To characterize the functional effect of this polymorphism on PARP1, we performed in vitro enzymatic analysis on PARP1-Ala762 and PARP1-Val762. We found that PARP1-Ala762 displayed 57.2% of the activity of PARP1-Val762 for auto-poly(ADP-ribosyl)ation and 61.9% of the activity of PARP1-Val762 for trans-poly(ADP-ribosyl)ation of histone H1. The kinetic characterization revealed that the K m of PARP1-Ala762 was increased to a 1.2-fold of the K m of PARP1-Val762 for trans-poly(ADP-ribosyl)ation. Thus, the PARP1 Val762Ala polymorphism reduces the enzymatic activity of PARP1 by increasing K m . This finding suggests that different levels of poly(ADP-ribosyl)ation by PARP1 might aid in understanding Cancer risk of carriers of the PARP1 Val762Ala polymorphism

  8. Fabrication of high surface area graphene electrodes with high performance towards enzymatic oxygen reduction

    International Nuclear Information System (INIS)

    Di Bari, Chiara; Goñi-Urtiaga, Asier; Pita, Marcos; Shleev, Sergey; Toscano, Miguel D.; Sainz, Raquel; De Lacey, Antonio L.

    2016-01-01

    High surface area graphene electrodes were prepared by simultaneous electrodeposition and electroreduction of graphene oxide. The electrodeposition process was optimized in terms of pH and conductivity of the solution and the obtained graphene electrodes were characterized by X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy and electrochemical methods (cyclic voltammetry and impedance spectroscopy). Electrodeposited electrodes were further functionalized to carry out covalent immobilization of two oxygen-reducing multicopper oxidases: laccase and bilirubin oxidase. The enzymatic electrodes were tested as direct electron transfer based biocathodes and catalytic currents as high as 1 mA/cm 2 were obtained. Finally, the mechanism of the enzymatic oxygen reduction reaction was studied for both enzymes calculating the Tafel slopes and transfer coefficients.

  9. Ship-borne measurements of microbial enzymatic activity: A rapid biochemical indicator for microbial water quality monitoring

    Science.gov (United States)

    Stadler, Philipp; Loken, Luke; Crawford, John; Schramm, Paul; Sorsa, Kirsti; Kuhn, Catherine; Savio, Domenico; Striegl, Rob; Butman, David; Stanley, Emily; Farnleitner, Andreas H.; Zessner, Matthias

    2017-04-01

    for ship-borne measurements of physico-chemical parameters, such as the FLAMe (Crawford et al., 2015), paves new ground for data interpretation and process understanding. Cabral, J.P.S., 2010. Water Microbiology. Bacterial Pathogens and Water. Int. J. Environ. Res. Public. Health 7, 3657-3703. doi:10.3390/ijerph7103657 Crawford, J.T., Loken, L.C., Casson, N.J., Smith, C., Stone, A.G., Winslow, L.A., 2015. High-speed limnology: using advanced sensors to investigate spatial variability in biogeochemistry and hydrology. Environ. Sci. Technol. 49, 442-450. doi:10.1021/es504773x Farnleitner, A. h., Hocke, L., Beiwl, C., Kavka, G. c., Zechmeister, T., Kirschner, A. k. t., Mach, R. l., 2001. Rapid enzymatic detection of Escherichia coli contamination in polluted river water. Lett. Appl. Microbiol. 33, 246-250. doi:10.1046/j.1472-765x.2001.00990.x Farnleitner, A.H., Hocke, L., Beiwl, C., Kavka, G.G., Mach, R.L., 2002. Hydrolysis of 4-methylumbelliferyl-β-d-glucuronide in differing sample fractions of river waters and its implication for the detection of fecal pollution. Water Res. 36, 975-981. doi:10.1016/S0043-1354(01)00288-3 Ryzinska-Paier, G., Lendenfeld, T., Correa, K., Stadler, P., Blaschke, A.P., Mach, R.L., Stadler, H., Kirschner, A.K.T., Farnleitner, A.H., 2014. A sensitive and robust method for automated on-line monitoring of enzymatic activities in water and water resources. Water Sci. Technol. J. Int. Assoc. Water Pollut. Res. 69, 1349-1358. doi:10.2166/wst.2014.032 Stadler, P., Blöschl, G., Vogl, W., Koschelnik, J., Epp, M., Lackner, M., Oismüller, M., Kumpan, M., Nemeth, L., Strauss, P., Sommer, R., Ryzinska-Paier, G., Farnleitner, A.H., Zessner, M., 2016. Real-time monitoring of beta-d-glucuronidase activity in sediment laden streams: A comparison of prototypes. Water Res. 101, 252-261. doi:10.1016/j.watres.2016.05.072 Stadler, P., Farnleitner, A.H., Zessner, M., 2017. Development and evaluation of a self-cleaning custom-built auto sampler controlled by a low

  10. Common HEXB polymorphisms reduce serum HexA and HexB enzymatic activities, potentially masking Tay-Sachs disease carrier identification.

    Science.gov (United States)

    Vallance, Hilary; Morris, Tara J; Coulter-Mackie, Marion; Lim-Steele, Joyce; Kaback, Michael

    2006-02-01

    A DNA-proven Tay-Sachs disease (TSD) carrier and his brother were found to have serum percent Hexosaminidase A (%HexA) enzymatic activities in the non-carrier range, while the leukocyte %HexA profiles clearly identified them as TSD heterozygotes. Both their serum HexA and HexB enzymatic activities were below reference range, suggesting inheritance of mutations in both the HEXA (alpha-subunit) and HEXB (beta-subunit) genes. DNA sequencing revealed that both individuals, carried the common HEXA 1277_1278insTATC mutation, and two common HEXB polymorphisms: [619A>G (+) delTG]. To determine if these HEXB polymorphisms reduce HexA and HexB enzymatic activities, 69 DNA samples from subjects previously screened enzymatically in both serum and leukocytes for TSD carrier status were selected for either high, mid-range or low serum Total Hex (defined as the sum of HexA and HexB) activities and were tested for the HEXB mutations. Further, three additional TSD carriers ascertained by the atypical pattern of normal serum %HexA but carrier leukocyte %HexA, were found to have the [delTG (+) 619A>G] genotype. In addition, the frequency of the [delTG (+) 619A>G] genotype was significantly higher (P G] haplotype in the Ashkenazi Jewish population (approximately 10%), up to 10% of TSD carriers may have normal serum %HexA values with low total Hex. Accordingly, serum %HexA should not be the sole criterion used for carrier status determination. Where total Hex activity is reduced, further testing with leukocyte Hex profiles is indicated.

  11. Destruction of enzymatic activities of corn and soybean leaves exposed to ozone

    Energy Technology Data Exchange (ETDEWEB)

    Leffler, H R; Cherry, J H

    1974-01-01

    Experiments were conducted to determine the effects of a single ozone exposure on selected enzymatic activities and chlorophyll contents of corn and soybean seedlings. Both nitrite reductase activity and chlorophyll content of the seedlings were found to be quite sensitive to ozonation and were seen to decrease as much as 50% after exposure to 80 parts per hundred million (pphm) ozone. After exposure to lower levels of ozone, less-pronounced decreases were observed. Nitrate reductase activity was reduced only after exposure to seedling leaf tissues to high concentrations of ozone. These results are discussed in relation to the concept of a two-phase response to oxidant exposure. The first phase is at the chloroplast level and is quite sensitive to the low as well as the high concentrations of ozone; the second is at the cellular level and is relatively resistant to all but the highest ozone concentrations. 27 references, 2 tables.

  12. Kinetics of enzymatic high-solid hydrolysis of lignocellulosic biomass studied by calorimetry.

    Science.gov (United States)

    Olsen, Søren N; Lumby, Erik; McFarland, Kc; Borch, Kim; Westh, Peter

    2011-03-01

    Enzymatic hydrolysis of high-solid biomass (>10% w/w dry mass) has become increasingly important as a key step in the production of second-generation bioethanol. To this end, development of quantitative real-time assays is desirable both for empirical optimization and for detailed kinetic analysis. In the current work, we have investigated the application of isothermal calorimetry to study the kinetics of enzymatic hydrolysis of two substrates (pretreated corn stover and Avicel) at high-solid contents (up to 29% w/w). It was found that the calorimetric heat flow provided a true measure of the hydrolysis rate with a detection limit of about 500 pmol glucose s(-1). Hence, calorimetry is shown to be a highly sensitive real-time method, applicable for high solids, and independent on the complexity of the substrate. Dose-response experiments with a typical cellulase cocktail enabled a multidimensional analysis of the interrelationships of enzyme load and the rate, time, and extent of the reaction. The results suggest that the hydrolysis rate of pretreated corn stover is limited initially by available attack points on the substrate surface (conversion) but becomes proportional to enzyme dosage (excess of attack points) at later stages (>10% conversion). This kinetic profile is interpreted as an increase in polymer end concentration (substrate for CBH) as the hydrolysis progresses, probably due to EG activity in the enzyme cocktail. Finally, irreversible enzyme inactivation did not appear to be the source of reduced hydrolysis rate over time.

  13. Laboratory-scale method for enzymatic saccharification of lignocellulosic biomass at high-solids loadings

    Directory of Open Access Journals (Sweden)

    Dibble Clare J

    2009-11-01

    Full Text Available Abstract Background Screening new lignocellulosic biomass pretreatments and advanced enzyme systems at process relevant conditions is a key factor in the development of economically viable lignocellulosic ethanol. Shake flasks, the reaction vessel commonly used for screening enzymatic saccharifications of cellulosic biomass, do not provide adequate mixing at high-solids concentrations when shaking is not supplemented with hand mixing. Results We identified roller bottle reactors (RBRs as laboratory-scale reaction vessels that can provide adequate mixing for enzymatic saccharifications at high-solids biomass loadings without any additional hand mixing. Using the RBRs, we developed a method for screening both pretreated biomass and enzyme systems at process-relevant conditions. RBRs were shown to be scalable between 125 mL and 2 L. Results from enzymatic saccharifications of five biomass pretreatments of different severities and two enzyme preparations suggest that this system will work well for a variety of biomass substrates and enzyme systems. A study of intermittent mixing regimes suggests that mass transfer limitations of enzymatic saccharifications at high-solids loadings are significant but can be mitigated with a relatively low amount of mixing input. Conclusion Effective initial mixing to promote good enzyme distribution and continued, but not necessarily continuous, mixing is necessary in order to facilitate high biomass conversion rates. The simplicity and robustness of the bench-scale RBR system, combined with its ability to accommodate numerous reaction vessels, will be useful in screening new biomass pretreatments and advanced enzyme systems at high-solids loadings.

  14. The dual effects of Maillard reaction and enzymatic hydrolysis on the antioxidant activity of milk proteins.

    Science.gov (United States)

    Oh, N S; Lee, H A; Lee, J Y; Joung, J Y; Lee, K B; Kim, Y; Lee, K W; Kim, S H

    2013-08-01

    The objective of this study was to determine the enhanced effects on the biological characteristics and antioxidant activity of milk proteins by the combination of the Maillard reaction and enzymatic hydrolysis. Maillard reaction products were obtained from milk protein preparations, such as whey protein concentrates and sodium caseinate with lactose, by heating at 55°C for 7 d in sodium phosphate buffer (pH 7.4). The Maillard reaction products, along with untreated milk proteins as controls, were hydrolyzed for 0 to 3h with commercial proteases Alcalase, Neutrase, Protamex, and Flavorzyme (Novozymes, Bagsværd, Denmark). The antioxidant activity of hydrolyzed Maillard reaction products was determined by reaction with 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt, their 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity, and the ability to reduce ferric ions. Further characteristics were evaluated by the o-phthaldialdehyde method and sodium dodecyl sulfate-PAGE. The degree of hydrolysis gradually increased in a time-dependent manner, with the Alcalase-treated Maillard reaction products being the most highly hydrolyzed. Radical scavenging activities and reducing ability of hydrolyzed Maillard reaction products increased with increasing hydrolysis time. The combined products of enzymatic hydrolysis and Maillard reaction showed significantly greater antioxidant activity than did hydrolysates or Maillard reaction products alone. The hydrolyzed Maillard reaction products generated by Alcalase showed significantly higher antioxidant activity when compared with the other protease products and the antioxidant activity was higher for the whey protein concentrate groups than for the sodium caseinate groups. These findings indicate that Maillard reaction products, coupled with enzymatic hydrolysis, could act as potential antioxidants in the pharmaceutical, food, and dairy industries. Copyright © 2013 American Dairy Science Association

  15. Conformational change results in loss of enzymatic activity of jack bean urease on its interaction with silver nanoparticle.

    Science.gov (United States)

    Ponnuvel, Shobana; Subramanian, Balakumar; Ponnuraj, Karthe

    2015-10-01

    Urease is an enzyme produced by microbes such as bacteria, yeast and fungi. Plants also produce this enzyme. Urease action splits urea into ammonia and carbamate. This action is having important implications in agro-chemical, medicinal and environment. Therefore there is always a constant search for new and novel compounds which could inhibit this enzyme. Here we have studied the interaction of jack bean urease (JBU) with silver nanoparticle to analyze the influence of the resultant protein corona formation on the catalytic property of JBU. Several techniques like UV-Vis, gel shift assay and CD spectroscopy have been used to characterize this interaction. Urease activity assay suggests that the protein corona formation inhibits the enzymatic action of JBU. The loss of enzymatic action could be either due to the nanoparticle blocking the active site of JBU or a conformational change in the protein. The CD spectra of JBU-AgNP complexes clearly revealed significant changes in the secondary structural composition of the JBU and this could be the reason for the loss of enzymatic activity of JBU. This study revealed an interesting observation, where the interaction of AgNP with JBU resulted destabilization of hexameric nature of JBU which is otherwise highly stable. The results of the present study could be useful in the development of nanoparticle based material for inhibiting the ureolytic activity of ureases in different fields.

  16. Optimization of enzymatic clarification of green asparagus juice using response surface methodology.

    Science.gov (United States)

    Chen, Xuehong; Xu, Feng; Qin, Weidong; Ma, Lihua; Zheng, Yonghua

    2012-06-01

    Enzymatic clarification conditions for green asparagus juice were optimized by using response surface methodology (RSM). The asparagus juice was treated with pectinase at different temperatures (35 °C-45 °C), pH values (4.00-5.00), and enzyme concentrations (0.6-1.8 v/v%). The effects of enzymatic treatment on juice clarity and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging capacity were investigated by employing a 3-factor central composite design coupled with RSM. According to response surface analysis, the optimal enzymatic treatment condition was pectinase concentration of 1.45%, incubation temperature of 40.56 °C and pH of 4.43. The clarity, juice yield, and soluble solid contents in asparagus juice were significantly increased by enzymatic treatment at the optimal conditions. DPPH radical-scavenging capacity was maintained at the level close to that of raw asparagus juice. These results indicated that enzymatic treatment could be a useful technique for producing green asparagus juice with high clarity and high-antioxidant activity. Treatment with 1.45% pectinase at 40.56 ° C, pH 4.43, significantly increased the clarity and yield of asparagus juice. In addition, enzymatic treatment maintained antioxidant activity. Thus, enzymatic treatment has the potential for industrial asparagus juice clarification. © 2012 Institute of Food Technologists®

  17. Influence of Different Lignocellulose Sources on Endo-1,4-β-Glucanase Gene Expression and Enzymatic Activity of Bacillus amyloliquefaciens B31C

    Directory of Open Access Journals (Sweden)

    Rosangela Di Pasqua

    2014-01-01

    Full Text Available Conversion of cellulose into fermentable sugars for ethanol production is currently performed by enzymatic hydrolysis catalyzed by cellulases. The cellulases are produced by a wide variety of microorganisms, playing a major role in the recycling of biomass. The endo-1,4-β-glucanase (CelB31C from Bacillus amyloliquefaciens B31C, isolated from compost and previously selected on the basis of highest cellulase activity levels among Bacillus isolated, was characterized as being a potential candidate for a biocatalyst in lignocellulose conversion for second-generation bioethanol production. The aim of this work was to evaluate the changes in production of enzymatic activity of the endo-1,4-β-glucanase (CelB31C and the expression of its gene (bglC using a carboxymethylcellulase activity assay and qRT-PCR analysis, respectively, during growth of B. amyloliquefaciens B31C on different cellulose sources: carboxymethylcellulose (CMC, pure cellulose from Arundo donax, pretreated Arundo donax biomass (Chemtex, and microcrystalline cellulose (Avicel. The results showed that both the expression of bglC gene and the enzymatic activity production are related to the type of cellulose source. The strain showed a high enzymatic activity on lignocellulosic biomass and on microcrystalline cellulose. Furthermore, the highest gene expression occurred during the exponential phase of growth, except in the presence of Avicel.

  18. Relationship of angiotensinase and vasopressinase enzymatic activities between hypothalamus and plasma in an obese rat model by high-fat diet

    Directory of Open Access Journals (Sweden)

    Germán Domínguez-Vías

    2016-07-01

    Full Text Available High-fat diets are associated with the development of hypertension. However, a high intake of monounsaturated fat has been proposed to be a dietary factor that can decrease the incidence of hypertension. The renin-angiotensin system (RAS and vasopressin interact to regulate blood pressure at central and peripheral level. In this study, we investigated the effect of different degrees of dietary fatty acid saturation in the control of RAS and vasopressin on brain-blood. To improve our understanding of their interaction and their relationship, we analyzed angiotensin- and vasopressin-metabolizing activities in hypothalamus and plasma, collected from Wistar rats fed during 24 weeks with diets enriched with extra virgin olive oil (monounsaturated fat or butter plus cholesterol (saturated fat compared with a standard diet. As results no angiotensinase and vasopressinase activities were found in hypothalamus and plasma, however significant correlations between enzymatic activities in both regions were noticed. They indicated that our results do not support the beneficial influence of extra virgin olive oil on central and systemic level to regulate blood pressure. Therefore, the substrates hydrolyzed by these activities as well as their functions may be similarly affected and suggest that these studies should be continued because of beneficial of Mediterranean diet, found previously in different works, which may also be an effective tool in the treatment of hypertension.

  19. Enzymatic synthesis of bioactive compounds with high potential for cosmeceutical application

    OpenAIRE

    Antonopoulou, Io; Varriale, Simona; Topakas, Evangelos; Rova, Ulrika; Christakopoulos, Paul; Faraco, Vincenza

    2016-01-01

    Cosmeceuticals are cosmetic products containing biologically active ingredients purporting to offer a pharmaceutical therapeutic benefit. The active ingredients can be extracted and purified from natural sources (botanicals, herbal extracts, or animals) but can also be obtained biotechnologically by fermentation and cell cultures or by enzymatic synthesis and modification of natural compounds. A cosmeceutical ingredient should possess an attractive property such as anti-oxidant, anti-inflamma...

  20. Binding of Nickel to Testicular Glutamate–Ammonia Ligase Inhibits Its Enzymatic Activity

    Science.gov (United States)

    SUN, YINGBIAO; OU, YOUNG; CHENG, MIN; RUAN, YIBING; VAN DER HOORN, FRANS A.

    2016-01-01

    SUMMARY Exposure to nickel has been shown to cause damage to the testis in several animal models. It is not known if the testis expresses protein(s) that can bind nickel. To test this, we used a nickel-binding assay to isolate testicular nickel-binding proteins. We identified glutamate–ammonia ligase (GLUL) as a prominent nickel-binding protein by mass spectrometry. Protein analysis and reverse transcriptase polymerase chain reaction showed that GLUL is expressed in the testis, predominantly in interstitial cells. We determined that GLUL has a higher affinity for nickel than for its regular co-factor manganese. We produced an enzymatically active, recombinant GLUL protein. Upon binding, nickel interferes with the manganese-catalyzed enzymatic activity of recombinant GLUL protein. We also determined that GLUL activity in testes of animals exposed to nickel sulfate is reduced. Our results identify testicular GLUL as the first testicular protein shown to be affected by nickel exposure. PMID:21254280

  1. Comparison of the role that entropy has played in processes of non-enzymatic and enzymatic catalysis

    International Nuclear Information System (INIS)

    Dixon Pineda, Manuel Tomas

    2012-01-01

    The function that entropy has played is compared in processes of non-enzymatic and enzymatic catalysis. The processes followed are showed: the kinetics of the acid hydrolysis of 3-pentyl acetate and cyclopentyl acetate catalyzed by hydrochloric acid and enzymatic hydrolysis of ethyl acetate and γ-butyrolactone catalyzed by pig liver esterase. The activation parameters of Eyring were determined for each process and interpreted the contribution of the entropy of activation for catalysis in this type of model reactions. (author) [es

  2. Constraints imposed by transmembrane domains affect enzymatic activity of membrane-associated human CD39/NTPDase1 mutants.

    Science.gov (United States)

    Musi, Elgilda; Islam, Naziba; Drosopoulos, Joan H F

    2007-05-01

    Human CD39/NTPDase1 is an endothelial cell membrane-associated nucleotidase. Its large extracellular domain rapidly metabolizes nucleotides, especially ADP released from activated platelets, inhibiting further platelet activation/recruitment. Previous studies using our recombinant soluble CD39 demonstrated the importance of residues S57, D54, and D213 for enzymatic/biological activity. We now report effects of S57A, D54A, and D213A mutations on full-length (FL)CD39 function. Enzymatic activity of alanine modified FLCD39s was less than wild-type, contrasting the enhanced activity of their soluble counterparts. Furthermore, conservative substitutions D54E and D213E led to enzymes with activities greater than the alanine modified FLCD39s, but less than wild-type. Reductions in mutant activities were primarily associated with reduced catalytic rates. Differences in enzymatic activity were not attributable to gross changes in the nucleotide binding pocket or the enzyme's ability to multimerize. Thus, composition of the active site of wild-type CD39 appears optimized for ADPase function in the context of the transmembrane domains.

  3. Enzymatic extraction of star gooseberry (Phyllanthus acidus) juice with high antioxidant level

    Science.gov (United States)

    Loan, Do Thi Thanh; Tra, Tran Thi Thu; Nguyet, Ton Nu Minh; Man, Le Van Viet

    2017-09-01

    Ascorbic acid and phenolic compounds are main antioxidants in star gooseberry (Phyllanthus acidus) fruit. In this study, Pectinex Ultra SP-L preparation with pectinase activity was used in the extraction of star gooseberry juice. The effects of pectinase concentration and biocatalytic time on the content of ascorbic acid, phenolic compounds and antioxidant activity of the fruit juice were firstly investigated. Response surface methodology was then used to optimize the conditions of enzymatic extraction for maximizing the antioxidant activity of the star gooseberry juice. The optimal pectinase concentration and biocatalytic time were 19 polygalacturonase units per 100g pulp dry weight and 67 min, respectively under which the maximal antioxidant activity achieved 5595±6 µmol Trolox equivalent per 100g juice dry weight. On the basis of kinetic model of second-order extraction, the extraction rate constant of ascorbic acid and phenolic compounds in the enzymatic extraction increased approximately 21% and 157%, respectively in comparison with that in the conventional extraction. Application of pectinase preparation to the fruit juice extraction was therefore potential for improvement in antioxidant level of the product.

  4. Metabolic regulation analysis of an ethanologenic Escherichia coli strain based on RT-PCR and enzymatic activities

    Directory of Open Access Journals (Sweden)

    Martinez Alfredo

    2008-05-01

    Full Text Available Abstract Background A metabolic regulation study was performed, based upon measurements of enzymatic activities, fermentation performance, and RT-PCR analysis of pathways related to central carbon metabolism, in an ethanologenic Escherichia coli strain (CCE14 derived from lineage C. In comparison with previous engineered strains, this E coli derivative has a higher ethanol production rate in mineral medium, as a result of the elevated heterologous expression of the chromosomally integrated genes encoding PDCZm and ADHZm (pyruvate decarboxylase and alcohol dehydrogenase from Zymomonas mobilis. It is suggested that this behavior might be due to lineage differences between E. coli W and C. Results This study demonstrated that the glycolytic flux is controlled, in this case, by reactions outside glycolysis, i.e., the fermentative pathways. Changes in ethanol production rate in this ethanologenic strain result in low organic acid production rates, and high glycolytic and ethanologenic fluxes, that correlate with enhanced transcription and enzymatic activity levels of PDCZm and ADHZm. Furthermore, a higher ethanol yield (90% of the theoretical in glucose-mineral media was obtained with CCE14 in comparison with previous engineered E. coli strains, such as KO11, that produces a 70% yield under the same conditions. Conclusion Results suggest that a higher ethanol formation rate, caused by ahigher PDCZm and ADHZm activities induces a metabolic state that cells compensate through enhanced glucose transport, ATP synthesis, and NAD-NADH+H turnover rates. These results show that glycolytic enzymatic activities, present in E. coli W and C under fermentative conditions, are sufficient to contend with increases in glucose consumption and product formation rates.

  5. A high performance non-enzymatic glucose sensor based on nickel hydroxide modified nitrogen-incorporated nanodiamonds.

    Science.gov (United States)

    Ko, Chih-Yu; Huang, Jin-Hua; Raina, Supil; Kang, Weng P

    2013-06-07

    A highly selective, sensitive, and stable non-enzymatic glucose sensor based on Ni hydroxide modified nitrogen-incorporated nanodiamonds (Ni(OH)2-NND) was developed. The sensor was fabricated by e-beam evaporation of a thin Ni film on NND followed by the growth of Ni(OH)2 using an electrochemical process. It was found that the Ni film thickness greatly affects the morphology and electro-catalytic activity of the as-synthesized electrode for non-enzymatic glucose oxidation. Owing to its nanostructure characteristics, the best sensor fabricated by 150 nm Ni deposition showed two wide response ranges, namely, 0.02-1 mM and 1-9 mM, with sensitivities of 3.20 and 1.41 mA mM(-1) cm(-2), respectively, and a detection limit of 1.2 μM (S/N = 3). The sensor also showed good long-term stability as well as high selectivity in the presence of interferences such as ascorbic acid, acetaminophen, and uric acid. This finding reveals the possibility of exploiting the NND as an electrochemical biosensor platform where high performance addressable sensor arrays could be built.

  6. Measure of enzymatic activity coincident with 2450 MHz microwave exposure

    Energy Technology Data Exchange (ETDEWEB)

    Ward, T R; Allis, J W; Elder, J A

    1975-09-01

    Enzyme preparations were exposed to microwave radiation at 2450 MHz and enzymatic activity was simultaneously monitored spectrophotometrically with a crossed-beam exposure detection system. Enzymes studied were glucose 6-phosphate dehydrogenase from human red blood cells and yeast, adenylate kinase from rat liver mitochondria and rabbit muscle, and rat liver microsomal NADPH cytochrome c reductase. No difference was found between the specific activity at 25/sup 0/C of unirradiated controls and enzyme preparations irradiated at an absorbed dose rate of 42 W/kg.

  7. Archetypal sandwich-structured CuO for high performance non-enzymatic sensing of glucose

    Science.gov (United States)

    Meher, Sumanta Kumar; Rao, G. Ranga

    2013-02-01

    In the quest to enhance the selectivity and sensitivity of novel structured metal oxides for electrochemical non-enzymatic sensing of glucose, we report here a green synthesis of unique sandwich-structured CuO on a large scale under microwave mediated homogeneous precipitation conditions. The physicochemical studies carried out by XRD and BET methods show that the monoclinic CuO formed via thermal decomposition of Cu2(OH)2CO3 possesses monomodal channel-type pores with largely improved surface area (~43 m2 g-1) and pore volume (0.163 cm3 g-1). The fascinating surface morphology and pore structure of CuO is formulated due to homogeneous crystallization and microwave induced self assembly during synthesis. The cyclic voltammetry and chronoamperometry studies show diffusion controlled glucose oxidation at ~0.6 V (vs. Ag/AgCl) with extremely high sensitivity of 5342.8 μA mM-1 cm-2 and respective detection limit and response time of ~1 μM and ~0.7 s, under a wide dynamic concentration range of glucose. The chronoamperometry measurements demonstrate that the sensitivity of CuO to glucose is unaffected by the absence of dissolved oxygen and presence of poisoning chloride ions in the reaction medium, which essentially implies high poison resistance activity of the sandwich-structured CuO. The sandwich-structured CuO also shows insignificant interference/significant selectivity to glucose, even in the presence of high concentrations of other sugars as well as reducing species. In addition, the sandwich-structured CuO shows excellent reproducibility (relative standard deviation of ~2.4% over ten identically fabricated electrodes) and outstanding long term stability (only ~1.3% loss in sensitivity over a period of one month) during non-enzymatic electrochemical sensing of glucose. The unique microstructure and suitable channel-type pore architecture provide structural stability and maximum accessible electroactive surface for unimpeded mobility of glucose as well as the

  8. Respiration and enzymatic activities as indicators of stabilization of sewage sludge composting.

    Science.gov (United States)

    Nikaeen, Mahnaz; Nafez, Amir Hossein; Bina, Bijan; Nabavi, BiBi Fatemeh; Hassanzadeh, Akbar

    2015-05-01

    The objective of this work was to study the evolution of physico-chemical and microbial parameters in the composting process of sewage sludge (SS) with pruning wastes (PW) in order to compare these parameters with respect to their applicability in the evaluation of organic matter (OM) stabilization. To evaluate the composting process and organic matter stability, different microbial activities were compared during composting of anaerobically digested SS with two volumetric ratios, 1:1 and 3:1 of PW:SS and two aeration techniques including aerated static piles (ASP) and turned windrows (TW). Dehydrogenase activity, fluorescein diacetate hydrolysis, and specific oxygen uptake rate (SOUR) were used as microbial activity indices. These indices were compared with traditional parameters, including temperature, pH, moisture content, organic matter, and C/N ratio. The results showed that the TW method and 3:1 (PW:SS) proportion was superior to the ASP method and 1:1 proportion, since the former accelerate the composting process by catalyzing the OM stabilization. Enzymatic activities and SOUR, which reflect microbial activity, correlated well with temperature fluctuations. Based on these results it appears that SOUR and the enzymatic activities are useful parameters to monitor the stabilization of SS compost. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Photoelectrochemical enzymatic biosensors.

    Science.gov (United States)

    Zhao, Wei-Wei; Xu, Jing-Juan; Chen, Hong-Yuan

    2017-06-15

    Enzymatic biosensors have been valuable bioanalytical devices for analysis of diverse targets in disease diagnosis, biological and biomedical research, etc. Photoelectrochemical (PEC) bioanalysis is a recently emerged method that promptly becoming a subject of new research interests due to its attractive potential for future bioanalysis with high sensitivity and specificity. PEC enzymatic biosensors integrate the inherent sensitivities of PEC bioanalysis and the selectivity of enzymes and thus share their both advantages. Currently, PEC enzymatic biosensors have become a hot topic of significant research and the recent impetus has grown rapidly as demonstrated by increased research papers. Given the pace of advances in this area, this review will make a thorough discussion and survey on the fundamentals, sensing strategies, applications and the state of the art in PEC enzymatic biosensors, followed by future prospects based on our own opinions. We hope this work could provide an accessible introduction to PEC enzymatic biosensors for any scientist. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Highly sensitive assay for tyrosine hydroxylase activity by high-performance liquid chromatography.

    Science.gov (United States)

    Nagatsu, T; Oka, K; Kato, T

    1979-07-21

    A highly sensitive assay for tyrosine hydroxylase (TH) activity by high-performance liquid chromatography (HPLC) with amperometric detection was devised based on the rapid isolation of enzymatically formed DOPA by a double-column procedure, the columns fitted together sequentially (the top column of Amberlite CG-50 and the bottom column of aluminium oxide). DOPA was adsorbed on the second aluminium oxide column, then eluted with 0.5 M hydrochloric acid, and assayed by HPLC with amperometric detection. D-Tyrosine was used for the control. alpha-Methyldopa was added to the incubation mixture as an internal standard after incubation. This assay was more sensitive than radioassays and 5 pmol of DOPA formed enzymatically could be measured in the presence of saturating concentrations of tyrosine and 6-methyltetrahydropterin. The TH activity in 2 mg of human putamen could be easily measured, and this method was found to be particularly suitable for the assay of TH activity in a small number of nuclei from animal and human brain.

  11. Highly efficient and enzymatic regioselective undecylenoylation of gastrodin in 2-methyltetrahydrofuran-containing systems.

    Science.gov (United States)

    Yang, Rongling; Liu, Xueming; Chen, Zhiyi; Yang, Chunying; Lin, Yaosheng; Wang, Siyuan

    2014-01-01

    Highly efficient and regioselective acylation of pharmacologically interesting gastrodin with vinyl undecylenic acid has been firstly performed through an enzymatic approach. The highest catalytic activity and regioselectivity towards the acylation of 7'-hydroxyl of gastrodin was obtained with Pseudomonas cepacia lipase. In addition, it was observed the lipase displayed higher activity in the eco-friendly solvent 2-methyltetrahydrofuran-containing systems than in other organic solvents. In the co-solvent mixture of tetrahydrofuran and 2-methyltetrahydrofuran (3/1, v/v), the reaction rate was 60.6 mM/h, substrate conversion exceeded 99%, and 7'-regioselectivity was 93%. It was also interesting that the lipase-catalyzed acylation couldn't be influenced by the benzylic alcohol in gastrodin. However, pseudomonas cepacia lipase displayed different regioselectivity towards gastrodin and arbutin.

  12. Comprehensive analysis to explain reduced or increased SOD1 enzymatic activity in ALS patients and their relatives.

    Science.gov (United States)

    Keskin, Isil; Birve, Anna; Berdynski, Mariusz; Hjertkvist, Karin; Rofougaran, Reza; Nilsson, Torbjörn K; Glass, Jonathan D; Marklund, Stefan L; Andersen, Peter M

    2017-08-01

    To characterise stabilities in erythrocytes of mutant SOD1 proteins, compare SOD1 enzymatic activities between patients with different genetic causes of ALS and search for underlying causes of deviant SOD1 activities in individuals lacking SOD1 mutations. Blood samples from 4072 individuals, ALS patients with or without a SOD1 mutation, family members and controls were studied. Erythrocyte SOD1 enzymatic activities normalised to haemoglobin content were determined, and effects of haemoglobin disorders on dismutation assessed. Coding SOD1 sequences were analysed by Sanger sequencing, exon copy number variations by fragment length analysis and by TaqMan Assay. Of the 44 SOD1 mutations found, 75% caused severe destabilisation of the mutant protein but in 25% it was physically stable. Mutations producing structural changes caused halved erythrocyte SOD1 activities. There were no differences in SOD1 activities between patients without a SOD1 mutation and control individuals or carriers of TBK1 mutations and C9orf72 HRE . In the low and high SOD1 activity groups no deviations were found in exon copy numbers and intron gross structures. Thalassemias and iron deficiency were associated with increased SOD1 activity/haemoglobin ratios. Adjunct erythrocyte SOD1 activity analysis reliably signals destabilising SOD1 mutations including intronic mutations that are missed by exon sequencing.

  13. Tunable Enzymatic Activity and Enhanced Stability of Cellulase Immobilized in Biohybrid Nanogels.

    Science.gov (United States)

    Peng, Huan; Rübsam, Kristin; Jakob, Felix; Schwaneberg, Ulrich; Pich, Andrij

    2016-11-14

    This paper reports a facile approach for encapsulation of enzymes in nanogels. Our approach is based on the use of reactive copolymers able to get conjugated with enzyme and build 3D colloidal networks or biohybrid nanogels. In a systematic study, we address the following question: how the chemical structure of nanogel network influences the biocatalytic activity of entrapped enzyme? The developed method allows precise control of the enzyme activity and improvement of enzyme resistance against harsh store conditions, chaotropic agents, and organic solvents. The nanogels were constructed via direct chemical cross-linking of water-soluble reactive copolymers poly(N-vinylpyrrolidone-co-N-methacryloxysuccinimide) with proteins such as enhanced green fluorescent protein (EGFP) and cellulase in water-in-oil emulsion. The water-soluble reactive copolymers with controlled amount of reactive succinimide groups and narrow dispersity were synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization. Poly(ethylene glycol) bis(3-aminopropyl) and branched polyethylenimine were utilized as model cross-linkers to optimize synthesis of nanogels with different architectures in the preliminary experiments. Biofluorescent nanogels with different loading amount of EGFP and varying cross-linking densities were obtained. We demonstrate that the biocatalytic activity of cellulase-conjugated nanogels (CNG) can be elegantly tuned by control of their cross-linking degrees. Circular dichroism (CD) spectra demonstrated that the secondary structures of the immobilized cellulase were changed in the aspect of α-helix contents. The secondary structures of cellulase in highly cross-linked nanogels were strongly altered compared with loosely cross-linked nanogels. The fluorescence resonance energy transfer (FRET) based study further revealed that nanogels with lower cross-linking degree enable higher substrate transport rate, providing easier access to the active site of

  14. The effect of high intensity mixing on the enzymatic hydrolysis of concentrated cellulose fiber suspensions

    Science.gov (United States)

    Joseph R. Samaniuk; C. Tim Scott; Thatcher W. Root; Daniel J. Klingenberg

    2011-01-01

    Enzymatic hydrolysis of lignocellulosic biomass in a high shear environment was examined. The conversion of cellulose to glucose in samples mixed in a torque rheometer producing shear flows similar to those found in twin screw extruders was greater than that of unmixed samples. In addition, there is a synergistic effect of mixing and enzymatic hydrolysis; mixing...

  15. Highly efficient and enzymatic regioselective undecylenoylation of gastrodin in 2-methyltetrahydrofuran-containing systems.

    Directory of Open Access Journals (Sweden)

    Rongling Yang

    Full Text Available Highly efficient and regioselective acylation of pharmacologically interesting gastrodin with vinyl undecylenic acid has been firstly performed through an enzymatic approach. The highest catalytic activity and regioselectivity towards the acylation of 7'-hydroxyl of gastrodin was obtained with Pseudomonas cepacia lipase. In addition, it was observed the lipase displayed higher activity in the eco-friendly solvent 2-methyltetrahydrofuran-containing systems than in other organic solvents. In the co-solvent mixture of tetrahydrofuran and 2-methyltetrahydrofuran (3/1, v/v, the reaction rate was 60.6 mM/h, substrate conversion exceeded 99%, and 7'-regioselectivity was 93%. It was also interesting that the lipase-catalyzed acylation couldn't be influenced by the benzylic alcohol in gastrodin. However, pseudomonas cepacia lipase displayed different regioselectivity towards gastrodin and arbutin.

  16. DNA-Based Sensor for Real-Time Measurement of the Enzymatic Activity of Human Topoisomerase I

    DEFF Research Database (Denmark)

    Marcussen, Lærke Bay; Jepsen, Morten Leth; Kristoffersen, Emil Laust

    2013-01-01

    Sensors capable of quantitative real-time measurements may present the easiest and most accurate way to study enzyme activities. Here we present a novel DNA-based sensor for specific and quantitative real-time measurement of the enzymatic activity of the essential human enzyme, topoisomerase I....... The basic design of the sensor relies on two DNA strands that hybridize to form a hairpin structure with a fluorophore-quencher pair. The quencher moiety is released from the sensor upon reaction with human topoisomerase I thus enabling real-time optical measurement of enzymatic activity. The sensor....... The cytotoxic effect of camptothecins correlates directly with the intracellular topoisomerase I activity. We therefore envision that the presented sensor may find use for the prediction of cellular drug response. Moreover, inhibition of topoisomerase I by camptothecin is readily detectable using the presented...

  17. Gamma radiation effect on biological activity and enzymatic properties of snake venoms

    International Nuclear Information System (INIS)

    Herrera, E.; Yarleque, A.; Campos, S.; Zavaleta, A.

    1986-01-01

    The effect of gamma radiation, from Co-60, on the biological activity and on some enzymatic activities, present in the venoms of Lachesis muta and Bothrops atrox, using samples of dried venom that had been irradiated at a dose of 0.1, 0.5 and 1.0 Mrad have been studied. Variations in the degree of hemorrhage and local necrosis were observed in albino mice injected subcutaneously with venoms of both types. The reduction of the biological activity was greater for the local hemorrhagic effect and was dependent on the doses of irradiation. The specific activity of various enzymes, present in both venoms, is affected by the gamma radiation, at a dose of 0.1 Mrad the order of increasing inactivation being: exonuclease (4%), phospholipase (24%), caseinolytic enzyme (20%), tamesterase (33%), a thrombine-like enzyme (40%), fibrinolytic enzyme (41%), 5'-nucleotidase (50%) and endonuclease (55%). The enzymatic inactivation was augmented by 0.5 and 1.0 Mrad, without maintaining an arithmetic relation. The enzyme of major resistance to the radiation was exonuclease, whereas 5'-nucleotidase and endonuclease were the most sensitive. No significant changes were observed in the spectrum of UV absorbtion (range 260 to 290 nm) nor in the contents of L-tyrosine in the irradiated venoms

  18. Relationship of angiotensin ase and vasopressin ase enzymatic activities between hypothalamus and plasma in an obese rat model by high-fat diet

    International Nuclear Information System (INIS)

    Domínguez-Vías, G.; Segarra Robles, A.B.; Ramirez-Sánchez, M.; Jiménez Serrano, S.

    2016-01-01

    High-fat diets are associated with the development of hypertension. However, a high intake of monounsaturated fat has been proposed to be a dietary factor that can decrease the incidence of hypertension. The renin-angiotensin system (RAS) and vasopressin interact to regulate blood pressure at central and peripheral level. In this study, we investigated the effect of different degrees of dietary fatty acid saturation in the control of RAS and vasopressin on brain-blood. To improve our understanding of their interaction and their relationship, we analyzed angiotensin- and vasopressin-metabolizing activities in hypothalamus and plasma, collected from Wistar rats fed during 24 weeks with diets enriched with extra virgin olive oil (monounsaturated fat) or butter plus cholesterol (saturated fat) compared with a standard diet. As results no angiotensinase and vasopressinase activities were found in hypothalamus and plasma, however significant correlations between enzymatic activities in both regions were noticed. They indicated that our results do not support the beneficial influence of extra virgin olive oil on central and systemic level to regulate blood pressure. Therefore, the substrates hydrolyzed by these activities as well as their functions may be similarly affected and suggest that these studies should be continued because of beneficial of Mediterranean diet, found previously in different works, which may also be an effective tool in the treatment of hypertension.

  19. Relationship of angiotensin ase and vasopressin ase enzymatic activities between hypothalamus and plasma in an obese rat model by high-fat diet

    Energy Technology Data Exchange (ETDEWEB)

    Domínguez-Vías, G.; Segarra Robles, A.B.; Ramirez-Sánchez, M.; Jiménez Serrano, S.

    2016-07-01

    High-fat diets are associated with the development of hypertension. However, a high intake of monounsaturated fat has been proposed to be a dietary factor that can decrease the incidence of hypertension. The renin-angiotensin system (RAS) and vasopressin interact to regulate blood pressure at central and peripheral level. In this study, we investigated the effect of different degrees of dietary fatty acid saturation in the control of RAS and vasopressin on brain-blood. To improve our understanding of their interaction and their relationship, we analyzed angiotensin- and vasopressin-metabolizing activities in hypothalamus and plasma, collected from Wistar rats fed during 24 weeks with diets enriched with extra virgin olive oil (monounsaturated fat) or butter plus cholesterol (saturated fat) compared with a standard diet. As results no angiotensinase and vasopressinase activities were found in hypothalamus and plasma, however significant correlations between enzymatic activities in both regions were noticed. They indicated that our results do not support the beneficial influence of extra virgin olive oil on central and systemic level to regulate blood pressure. Therefore, the substrates hydrolyzed by these activities as well as their functions may be similarly affected and suggest that these studies should be continued because of beneficial of Mediterranean diet, found previously in different works, which may also be an effective tool in the treatment of hypertension.

  20. High-solids loading enzymatic hydrolysis of waste papers for biofuel production

    International Nuclear Information System (INIS)

    Wang, Lei; Templer, Richard; Murphy, Richard J.

    2012-01-01

    Highlights: ► Waste papers have great potential as a feedstock for bioethanol production. ► A wet blending step would significantly enhance enzymatic hydrolysis efficiency. ► High-solids loading saccharification was performed successfully on waste papers. ► Saccharification data were from four types of paper and two enzyme alternatives. ► Enzymatic hydrolysis kinetic models were validated by experimental data. -- Abstract: Waste papers (newspaper, office paper, magazines and cardboard in this study) with 50–73% (w/w oven dry weight) carbohydrate contents have considerable potential as raw materials for bioethanol production. A particle size reduction step of wet blending prior to enzymatic hydrolysis of newspaper was found to increase the glucan conversion efficiency by up to 10%. High-solids loading hydrolysis at 15% (w/w) of four types of paper using two enzyme alternatives, Celluclast 1.5L supplemented with Novozyme 188 and Cellic Ctec 1 (Novozymes A/S, Demark), at various enzyme concentrations were successfully performed in a lab-scale overhead-stirred reactor. This work has identified the relative saccharification performance for the four types of paper and shows office paper and cardboard to be more suitable for producing bioethanol than newspaper or magazine paper. The experimental data were also very well described by a modified, simple three parameter glucan and xylan hydrolysis model. These findings provide the possibility for incorporating this validated kinetic model into process designs required for commercial scale bioethanol production from waste paper resources.

  1. Decreased enzymatic activity of 5,10-methylene tetrahydrofolate reductase affects the development of several diseases

    Directory of Open Access Journals (Sweden)

    Maša Vidmar

    2016-07-01

    Full Text Available The importance of folates in human physiology is well known, as are various pathologies associated with low folate status. Folate deficiency can occur due to low dietary intake, genetic predisposition or treatment with medicines affecting the folate status. The aim of this paper is to explore the importance of determining genetic polymorphisms which influence the levels of biologically active folate. MTHFR is involved in the transformation of 5,10-methylene-THF to 5-methyl-THF. Polymorphisms of the MTHRF gene are associated with decreased enzymatic activity.Only 9.3 % of the population in Slovenia displays full activity of the MTHFR enzyme; these subjects are non-mutated homozygotes (wild-type alleles. In contrast, the average enzymatic activity in subjects with mutated alleles is between 50 and 60 %. MTHFR polymorphism is associated with an increased risk of hyperhomocysteinemia and cardiovascular diseases, neurological disorders and various types of cancer. There is also an increased risk for congenital malformations. Folic acid food fortification was introduced in some countries in order to assure an adequate folate status in the population. However, this approach does not address the decreased activity of MTHFR.Polymorphism in the key enzymes of the folate cycle is common. Determination of the genetic predisposition is therefore plausible in the most vulnerable groups of the population, such as pregnant women and patients receiving medicines influencing the folate cycle in various ways, e.g. 5-fluorouracil, methotrexate and 6-mercaptopurine. Genotyping would allow the identification of patients at high risk for suboptimal folate status.

  2. Highly ordered Ni–Ti–O nanotubes for non-enzymatic glucose detection

    Energy Technology Data Exchange (ETDEWEB)

    Hang, Ruiqiang, E-mail: hangruiqiang@tyut.edu.cn [Research Institute of Surface Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Liu, Yanlian [Research Institute of Surface Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Gao, Ang [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China); Bai, Long; Huang, Xiaobo; Zhang, Xiangyu; Lin, Naiming [Research Institute of Surface Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Tang, Bin, E-mail: tangbin@tyut.edu.cn [Research Institute of Surface Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Chu, Paul K. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China)

    2015-06-01

    Anodization is used to fabricate Ni–Ti–O nanotube (NT) electrodes for non-enzymatic glucose detection. The morphology, microstructure and composition of the materials are characterized by field emission scanning electron microscopy (FE-SEM), high resolution transmission electron microscopy (HR-TEM) and X-ray photoelectron spectroscopy (XPS). Our results show amorphous and highly ordered NTs with diameter of 50 nm, length of 800 nm, and Ni/Ti ratio (at %) of 0.35 can be fabricated in ethylene glycol electrolyte supplemented with 0.2 wt.% NH{sub 4}F and 0.5 vol.% H{sub 2}O at 30 °C and 25 V for 1 h. Electrochemical experiments indicate that at an applied potential of 0.60 V vs. Ag/AgCl, the electrode exhibits a linear response window for glucose concentrations from 0.002 mM to 0.2 mM with a response time of 10 s, detection limit of 0.13 μM (S/N = 3), and sensitivity of 83 μA mM{sup −1} cm{sup −2}. The excellent performance of the electrode is attributed to its large specific area and fast electron transfer between the NT walls. The good electrochemical performance of the Ni–Ti–O NTs as well as their simple and low-cost preparation method make the strategy promising in non-enzymatic glucose detection. - Highlights: • Highly ordered Ni–Ti–O nanotubes have been fabricated by one-step anodization. • We find H{sub 2}O contents in the electrolyte is critical to successful fabrication of the NTs. • The Ni–Ti–O nanotubes are ideal electrode materials for non-enzymatic glucose detection.

  3. Effect of wheat and Miscanthus straw biochars on soil enzymatic activity, ecotoxicity, and plant yield

    Science.gov (United States)

    Mierzwa-Hersztek, Monika; Gondek, Krzysztof; Klimkowicz-Pawlas, Agnieszka; Baran, Agnieszka

    2017-07-01

    The variety of technological conditions and raw materials from which biochar is produced is the reason why its soil application may have different effects on soil properties and plant growth. The aim of this study was to evaluate the effect of the addition of wheat straw and Miscanthus giganteus straw (5 t DM ha-1) and biochar obtained from this materials in doses of 2.25 and 5 t DM ha-1 on soil enzymatic activity, soil ecotoxicity, and plant yield (perennial grass mixture with red clover). The research was carried out under field conditions on soil with the granulometric composition of loamy sand. No significant effect of biochar amendment on soil enzymatic activity was observed. The biochar-amended soil was toxic to Vibrio fischeri and exhibited low toxicity to Heterocypris incongruens. Application of wheat straw biochar and M. giganteus straw biochar in a dose of 5 t DM ha-1 contributed to an increase in plant biomass production by 2 and 14%, respectively, compared to the soil with mineral fertilisation. Biochars had a more adverse effect on soil enzymatic activity and soil ecotoxicity to H. incongruens and V. fischeri than non-converted wheat straw and M. giganteus straw, but significantly increased the grass crop yield.

  4. Oculocutaneous albinism type 1: link between mutations, tyrosinase conformational stability, and enzymatic activity.

    Science.gov (United States)

    Dolinska, Monika B; Kus, Nicole J; Farney, S Katie; Wingfield, Paul T; Brooks, Brian P; Sergeev, Yuri V

    2017-01-01

    Oculocutaneous albinism type 1 (OCA1) is an autosomal recessive disorder caused by mutations in the tyrosinase gene. Two subtypes of OCA1 have been described: severe OCA1A with complete absence of tyrosinase activity and less severe OCA1B with residual tyrosinase activity. Here, we characterize the recombinant human tyrosinase intramelanosomal domain and mutant variants, which mimic genetic changes in both subtypes of OCA1 patients. Proteins were prepared using site-directed mutagenesis, expressed in insect larvae, purified by chromatography, and characterized by enzymatic activities, tryptophan fluorescence, and Gibbs free energy changes. The OCA1A mutants showed very low protein expression and protein yield and are enzymatically inactive. Mutants mimicking OCA1B were biochemically similar to the wild type, but exhibited lower specific activities and protein stabilities. The results are consistent with clinical data, which indicates that OCA1A mutations inactivate tyrosinase and result in severe phenotype, while OCA1B mutations partially inactivate tyrosinase and result in OCA1B albinism. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.

  5. Chemical Characterization, Antioxidant and Enzymatic Activity of Brines from Scandinavian Marinated Herring Products

    DEFF Research Database (Denmark)

    Gringer, Nina; Osman, Ali; Nielsen, Henrik Hauch

    2014-01-01

    Brines generated during the last marination step in the production of marinated herring (Clupea harengus) were chemically characterized and analyzed for antioxidant and enzyme activities. The end-products were vinegar cured, spice cured and traditional barrel-salted herring with either salt...... or spices. The chemical characterization encompassed pH, dry matter, ash, salt, fatty acids, protein, polypeptide pattern, iron and nitrogen. The antioxidant activity was tested with three assays measuring: iron chelation, reducing power and radical scavenging activity. The enzymatic activity for peroxidase...

  6. Enzymatic Processes in Marine Biotechnology.

    Science.gov (United States)

    Trincone, Antonio

    2017-03-25

    In previous review articles the attention of the biocatalytically oriented scientific community towards the marine environment as a source of biocatalysts focused on the habitat-related properties of marine enzymes. Updates have already appeared in the literature, including marine examples of oxidoreductases, hydrolases, transferases, isomerases, ligases, and lyases ready for food and pharmaceutical applications. Here a new approach for searching the literature and presenting a more refined analysis is adopted with respect to previous surveys, centering the attention on the enzymatic process rather than on a single novel activity. Fields of applications are easily individuated: (i) the biorefinery value-chain, where the provision of biomass is one of the most important aspects, with aquaculture as the prominent sector; (ii) the food industry, where the interest in the marine domain is similarly developed to deal with the enzymatic procedures adopted in food manipulation; (iii) the selective and easy extraction/modification of structurally complex marine molecules, where enzymatic treatments are a recognized tool to improve efficiency and selectivity; and (iv) marine biomarkers and derived applications (bioremediation) in pollution monitoring are also included in that these studies could be of high significance for the appreciation of marine bioprocesses.

  7. Changes in the amino acid profiles and free radical scavenging activities of Tenebrio molitor larvae following enzymatic hydrolysis.

    Science.gov (United States)

    Tang, Yujiao; Debnath, Trishna; Choi, Eun-Ju; Kim, Young Wook; Ryu, Jung Pyo; Jang, Sejin; Chung, Sang Uk; Choi, Young-Jin; Kim, Eun-Kyung

    2018-01-01

    Tenebrio molitor (T. molitor) larvae provide food at low environmental cost and contribute positively to livelihoods. In this research, we compared the amino acids compositions and antioxidant activities of various extracts of T. molitor to enhance their quality as food. For the comparison, distilled water extracts, enzymatic hydrolysates, and condensed enzymatic hydrolysates of T. molitor larvae were prepared. Their amino acids (AAs) profiles and antioxidant activities, including ferric-reducing antioxidant power, oxygen radical absorption capacity, and DPPH, hydroxyl radical, and hydrogen peroxide radical scavenging properties assay were analyzed. DW extracts had the lowest AAs contents and antioxidant activity compared with enzymatic extracts. Condensed hydrolysates with a combination of alcalase and flavourzyme (C-A+F) exhibited the highest levels of total free AAs (11.1759 g/100 g). C-A+F produced higher total hydrolyzed AAs (32.5292 g/100 g) compared with the other groups. The C-A+F possessed the strongest antioxidant activity. Notably, the antioxidant activities of the hydrolysates and the total hydrolyzed AAs amount were correlated. Taken together, our findings showed that C-A+F was a promising technique for obtaining extracts of T. molitor larvae with antioxidant activity as potential nutritious functional food.

  8. Effect of enzymatic mash treatment and storage on phenolic composition, antioxidant activity, and turbidity of cloudy apple juice.

    Science.gov (United States)

    Oszmiański, Jan; Wojdylo, Aneta; Kolniak, Joanna

    2009-08-12

    The effects of different commercial enzymatic mash treatments on yield, turbidity, color, and polyphenolic and sediment of procyanidins content of cloudy apple juice were studied. Addition of pectolytic enzymes to mash treatment had positive effect on the production of cloud apple juices by improving polyphenolic contents, especially procyanidins and juice yields (68.3% in control samples to 77% after Pectinex Yield Mash). As summary of the effect of enzymatic mash treatment, polyphenol contents in cloudy apple juices significantly increased after Pectinex Yield Mash, Pectinex Smash XXL, and Pectinex XXL maceration were applied but no effect was observed after Pectinex Ultra-SPL I Panzym XXL use, compared to the control samples. The content of polymeric procyanidins represented 50-70% of total polyphenols, but in the present study, polymeric procyanidins were significantly lower in juices than in fruits and also affected by enzymatic treatment (Pectinex AFP L-4 and Panzym Yield Mash) compared to the control samples. The enzymatic treatment decreased procyanidin content in most sediment with the exception of Pectinex Smash XXL and Pectinex AFP L-4. Generally in samples that were treated by pectinase, radical scavenging activity of cloudy apple juices was increased compared to the untreated reference samples. The highest radical scavenging activity was associated with Pectinex Yield Mash, Pectinex Smash XXL, and Pectinex XXL enzyme and the lowest activity with Pectinex Ultra SP-L and Pectinex APFL-4. However, in the case of enzymatic mash treatment cloudy apple juices showed instability of turbidity and low viscosity. These results must be ascribed to the much higher hydrolysis of pectin by enzymatic preparation which is responsible for viscosity. During 6 months of storage at 4 degrees C small changes in analyzed parameters of apple juices were observed.

  9. Mussel-inspired co-deposition to enhance bisphenol A removal in a bifacial enzymatic membrane reactor

    DEFF Research Database (Denmark)

    Cao, Xiaotong; Luo, Jianquan; Woodley, John M.

    2018-01-01

    were used as the matrix to further exploit the potential of the biocatalytic membranes. such prepared biocatalytic membranes were enzymatically active on both sides, making it possible to construct a bifacial enzymatic membrane reactor (EMR) for highly efficient micro-pollutants removal (taking...

  10. Modelling the Effects of Ageing Time of Starch on the Enzymatic Activity of Three Amylolytic Enzymes

    Science.gov (United States)

    Guerra, Nelson P.; Pastrana Castro, Lorenzo

    2012-01-01

    The effect of increasing ageing time (t) of starch on the activity of three amylolytic enzymes (Termamyl, San Super, and BAN) was investigated. Although all the enzymatic reactions follow michaelian kinetics, v max decreased significantly (P enzymes and the release of the reaction products to the medium. A similar effect was observed when the enzymatic reactions were carried out with unaged starches supplemented with different concentrations of gelatine [G]. The inhibition in the amylolytic activities was best mathematically described by using three modified forms of the Michaelis-Menten model, which included a term to consider, respectively, the linear, exponential, and hyperbolic inhibitory effects of t and [G]. PMID:22666116

  11. Enzyme-Initiated Quinone-Chitosan Conjugation Chemistry: Toward A General in Situ Strategy for High-Throughput Photoelectrochemical Enzymatic Bioanalysis.

    Science.gov (United States)

    Wang, Guang-Li; Yuan, Fang; Gu, Tiantian; Dong, Yuming; Wang, Qian; Zhao, Wei-Wei

    2018-02-06

    Herein we report a general and novel strategy for high-throughput photoelectrochemical (PEC) enzymatic bioanalysis on the basis of enzyme-initiated quinone-chitosan conjugation chemistry (QCCC). Specifically, the strategy was illustrated by using a model quinones-generating oxidase of tyrosinase (Tyr) to catalytically produce 1,2-bezoquinone or its derivative, which can easily and selectively be conjugated onto the surface of the chitosan deposited PbS/NiO/FTO photocathode via the QCCC. Upon illumination, the covalently attached quinones could act as electron acceptors of PbS quantum dots (QDs), improving the photocurrent generation and thus allowing the elegant probing of Tyr activity. Enzyme cascades, such as alkaline phosphatase (ALP)/Tyr and β-galactosidase (Gal)/Tyr, were further introduced into the system for the successful probing of the corresponding targets. This work features not only the first use of QCCC in PEC bioanalysis but also the separation of enzymatic reaction from the photoelectrode as well as the direct signal recording in a split-type protocol, which enables quite convenient and high-throughput detection as compared to previous formats. More importantly, by using numerous other oxidoreductases that involve quinones as reactants/products, this protocol could serve as a common basis for the development of a new class of QCCC-based PEC enzymatic bioanalysis and further extended for general enzyme-labeled PEC bioanalysis of versatile targets.

  12. Specific inflammatory response of Anemonia sulcata (Cnidaria) after bacterial injection causes tissue reaction and enzymatic activity alteration.

    Science.gov (United States)

    Trapani, M R; Parisi, M G; Parrinello, D; Sanfratello, M A; Benenati, G; Palla, F; Cammarata, M

    2016-03-01

    The evolution of multicellular organisms was marked by adaptations to protect against pathogens. The mechanisms for discriminating the ''self'' from ''non-self" have evolved into a long history of cellular and molecular strategies, from damage repair to the co-evolution of host-pathogen interactions. We investigated the inflammatory response in Anemonia sulcata (Cnidaria: Anthozoa) following injection of substances that varied in type and dimension, and observed clear, strong and specific reactions, especially after injection of Escherichia coli and Vibrio alginolyticus. Moreover, we analyzed enzymatic activity of protease, phosphatase and esterase, showing how the injection of different bacterial strains alters the expression of these enzymes and suggesting a correlation between the appearance of the inflammatory reaction and the modification of enzymatic activities. Our study shows for the first time, a specific reaction and enzymatic responses following injection of bacteria in a cnidarian. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Bioethanol production: an integrated process of low substrate loading hydrolysis-high sugars liquid fermentation and solid state fermentation of enzymatic hydrolysis residue.

    Science.gov (United States)

    Chu, Qiulu; Li, Xin; Ma, Bin; Xu, Yong; Ouyang, Jia; Zhu, Junjun; Yu, Shiyuan; Yong, Qiang

    2012-11-01

    An integrated process of enzymatic hydrolysis and fermentation was investigated for high ethanol production. The combination of enzymatic hydrolysis at low substrate loading, liquid fermentation of high sugars concentration and solid state fermentation of enzymatic hydrolysis residue was beneficial for conversion of steam explosion pretreated corn stover to ethanol. The results suggested that low substrate loading hydrolysis caused a high enzymatic hydrolysis yield; the liquid fermentation of about 200g/L glucose by Saccharomyces cerevisiae provided a high ethanol concentration which could significantly decrease cost of the subsequent ethanol distillation. A solid state fermentation of enzymatic hydrolysis residue was combined, which was available to enhance ethanol production and cellulose-to-ethanol conversion. The results of solid state fermentation demonstrated that the solid state fermentation process accompanied by simultaneous saccharification and fermentation. Copyright © 2012 Elsevier Ltd. All rights reserved.

  14. Rapid tryptic mapping using enzymatically active mass spectrometer probe tips

    Energy Technology Data Exchange (ETDEWEB)

    Dogruel, D.; Williams, P.; Nelson, R.W. [Arizona State Univ., Tempe, AZ (United States)

    1995-12-01

    A method has been developed for rapid, sensitive, and accurate tryptic mapping of polypeptides using matrix-assisted laser desorption/ionization time-of-flight mass analysis. The technique utilizes mass spectrometer probe tips which have been activated through the covalent immobilization of trypsin. The enzymatically active probe tips were used for the tryptic mapping of chicken egg lysozyme and the results compared with those obtained using either free trypsin or agarose-immobilized trypsin. A significant increase in the overall sensitivity of the process was observed using the active probe tips, as well as the production of more characteristic proteolytic fragments and the elimination of background signals due to the autolysis of the trypsin. Further, probe tip digestions were found to be rapid and convenient. 19 refs., 6 figs., 2 tabs.

  15. Oxidant and enzymatic antioxidant status (gene expression and activity) in the brain of chickens with cold-induced pulmonary hypertension

    Science.gov (United States)

    Hassanpour, Hossein; Khalaji-Pirbalouty, Valiallah; Nasiri, Leila; Mohebbi, Abdonnaser; Bahadoran, Shahab

    2015-11-01

    To evaluate oxidant and antioxidant status of the brain (hindbrain, midbrain, and forebrain) in chickens with cold-induced pulmonary hypertension, the measurements of lipid peroxidation, protein oxidation, antioxidant capacity, enzymatic activity, and gene expression (for catalase, glutathione peroxidase, and superoxide dismutases) were done. There were high lipid peroxidation/protein oxidation and low antioxidant capacity in the hindbrain of cold-induced pulmonary hypertensive chickens compared to control ( P pulmonary hypertension.

  16. An Investigation of the Changes in Enzymatic and Non-Enzymatic Salivary Antioxidants Caused by Exhausting Aerobic Activity in Non-Athletic Men

    Directory of Open Access Journals (Sweden)

    Yazgaldi Nazari

    2016-12-01

    Full Text Available Background and Objectives: In the present study, the effect of acute aerobic exercise on enzymatic and non-enzymatic salivary antioxidants variations in non-athlete men, was investigated. Methods: In this experimental study, 25 male non-athlete collegiates (age, 21.2±1.6 years; weight, 68.62±10.1kg; body fat, 16.75±2.9%; and Vo2 max, 37.54±2.4ml/kg/min participated voluntarily in this study. Saliva samples were collected in three phases (before, immediately, and 1 hour after running on treadmill according to Astrand test. The activity of peroxidase and catalase, and concentration of uric acid were measured by laboratory methods. Then, to assess the obtained changes, repeated measures statistical test, and in case of significance, post-hoc Bonferroni test were used for pairwise comparing of the measuring phases at the significance level of p≤0.05 used.  Results: The activity of peroxidase significantly increased immediately and 1 hour after exercise compared to the baseline; Also, the concentration of uric acid significantly increased after aerobic exercise, but catalase enzyme activity significantly decreased after aerobic exercise (p<0.05. No significant change was observed in saliva flow rate after exercise. Conclusion: According to the findings of this study, aerobic exercise causes the production of free radicals, and salivary antioxidant system increases as the body biological response to neutralize and counteract the damaging effects of free radicals.

  17. Enzymatic saccharification of high pressure assist-alkali pretreated cotton stalk and structural characterization.

    Science.gov (United States)

    Du, Shuang-kui; Su, Xia; Yang, Weihua; Wang, Yanqin; Kuang, Meng; Ma, Lei; Fang, Dan; Zhou, Dayun

    2016-04-20

    Cotton stalk is a potential biomass for bioethanol production, while the conversion of direct saccharification or biotransformation of cotton stalk is extremely low due to the recalcitrant nature of lignocellulose. To enhance the enzymatic conversion of cotton stalks, the enzymatic saccharification parameters of high pressure assist-alkali pretreatment (HPAP) cotton stalk were optimized in the present study. Results indicated that a maximum reducing sugar yield of 54.7g/100g dry biomass cellulose was achieved at a substrate concentration of 2%, 100rpm agitation, 0.6g/g enzyme loading, 40°C hydrolysis temperature, 50h saccharification time, and pH 5.0. Scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy were used to identify structural changes in native, pretreated biomass and hydrolyzed residues. Structural analysis revealed large part of amorphous cellulose and partial crystalline cellulose in the HPAP cotton stalk were hydrolyzed during enzymatic treatment. HPAP cotton stalk can be used as a potential feed stock for bioethanol production. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Ultrasound-assisted enzymatic extraction and antioxidant activity of polysaccharides from pumpkin (Cucurbita moschata).

    Science.gov (United States)

    Wu, Hao; Zhu, Junxiang; Diao, Wenchao; Wang, Chengrong

    2014-11-26

    An efficient ultrasound-assisted enzymatic extraction (UAEE) of Cucurbita moschata polysaccharides (CMCP) was established and the CMCP antioxidant activities were studied. The UAEE operating parameters (extraction temperature, ultrasonic power, pH, and liquid-to-material ratio) were optimized using the central composite design (CCD) and the mass transfer kinetic study in UAEE procedure was used to select the optimal extraction time. Enzymolysis and ultrasonication that were simultaneously conducted was selected as the UAEE synergistic model and the optimum extraction conditions with a maximum polysaccharide yield of 4.33 ± 0.15% were as follows: extraction temperature, 51.5 °C; ultrasonic power, 440 W; pH, 5.0; liquid-to-material ratio, 5.70:1 mL/g; and extraction time, 20 min. Evaluation of the antioxidant activity in vitro suggested that CMCP has good potential as a natural antioxidant used in the food or medicine industry because of their high reducing power and positive radical scavenging activity for DPPH radical. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Yield-determining factors in high-solids enzymatic hydrolysis of lignocellulose

    Directory of Open Access Journals (Sweden)

    Felby Claus

    2009-06-01

    Full Text Available Abstract Background Working at high solids (substrate concentrations is advantageous in enzymatic conversion of lignocellulosic biomass as it increases product concentrations and plant productivity while lowering energy and water input. However, for a number of lignocellulosic substrates it has been shown that at increasing substrate concentration, the corresponding yield decreases in a fashion which can not be explained by current models and knowledge of enzyme-substrate interactions. This decrease in yield is undesirable as it offsets the advantages of working at high solids levels. The cause of the 'solids effect' has so far remained unknown. Results The decreasing conversion at increasing solids concentrations was found to be a generic or intrinsic effect, describing a linear correlation from 5 to 30% initial total solids content (w/w. Insufficient mixing has previously been shown not to be involved in the effect. Hydrolysis experiments with filter paper showed that neither lignin content nor hemicellulose-derived inhibitors appear to be responsible for the decrease in yields. Product inhibition by glucose and in particular cellobiose (and ethanol in simultaneous saccharification and fermentation at the increased concentrations at high solids loading plays a role but could not completely account for the decreasing conversion. Adsorption of cellulases was found to decrease at increasing solids concentrations. There was a strong correlation between the decreasing adsorption and conversion, indicating that the inhibition of cellulase adsorption to cellulose is causing the decrease in yield. Conclusion Inhibition of enzyme adsorption by hydrolysis products appear to be the main cause of the decreasing yields at increasing substrate concentrations in the enzymatic decomposition of cellulosic biomass. In order to facilitate high conversions at high solids concentrations, understanding of the mechanisms involved in high-solids product inhibition

  20. Identification and enzymatic characterization of the yeasts isolated from Erzincan tulum cheese

    Directory of Open Access Journals (Sweden)

    S. Karasu-Yalcin

    2012-03-01

    Full Text Available In this study, 146 yeast isolates were obtained from 45 Erzincan tulum cheese samples. By using API ID 32C test system and some complementary morphological, physiological and biochemica tests, 121 of the isolates could be identified at species level, while 12 of them were identified at genus level. The identified yeast isolates belonged to six different genera which were Candida, Geotrichum, Kluyveromyces, Pichia, Saccharomyces and Zygosaccharomyces. The most aboundant species was C. lambica, followed by C. zeylanoides, C. famata var. famata, G. candidum and C. kefyr. Enzymatic characterization of the strains was determined by using API-ZYM test system. All of the isolates had leucin arylamidase activity. Eight strains belonging to S. cerevisiae, Z. mellis, G. candidum and P. fermentans were found to have high leucin arylamidase activities. Most of the isolates had β-galactosidase, acid phosphatase and esterase lipase (C8 activities. Eight investigated C. lambica strains had high acid phosphatase activities. Such enzymatic properties of investigated yeast isolates could be fundamental factor for their application as starter culture candidates in production of Erzincan tulum cheese. It was demonstrated that the strain C. lambica T103 had superior enzymatic characteristics with the potential to be used in further technological investigations as an adjunct starter.

  1. Impact of Heavy Metals in Enzymatic Activity of Soils from Hidalgo, Mexico

    International Nuclear Information System (INIS)

    Reyes-Ortigoza, A. L.; Reyes-Solis, I. E.; Galicia-Palacios, M. S.; Montiel-Arteaga, S.

    2009-01-01

    The soils from Valle of Mezquital, Hidalgo, Mexico have been irrigated with waste waters from Mexico City for more than 88 years. the present investigation was made in order to know the relationship between heavy metal contents and time of irrigation with waste waters and production of CO 2 and enzymatic activity in soils from Valle Mezquital for knowing the disponibility of nutrients and degradation of soils. (Author)

  2. Influence of season, environment and feeding habits on the enzymatic activity of peptidase and β-glucosidase in the gastrointestinal tract of two Siluriformes fishes (Teleostei

    Directory of Open Access Journals (Sweden)

    Silvana Duarte

    2013-06-01

    Full Text Available The enzymatic activities involved in the digestion of proteins and carbohydrates were compared among three organs of the digestive track of two Siluriformes fish species, and between two areas: a reservoir, and an area downriver of it. Our aim was to test the hypothesis that the digestive organs of species with varied feeding habits have different enzymatic activities, and that the enzymatic activity differs among seasons and environmental conditions. The iliophagous/herbivorous species Hypostomus auroguttatus Kner, 1854 had higher trypsin-like, chymotrypsin-like peptidase and β-glucosidase activity in the intestine when compared with the omnivorous species Pimelodus maculatus Lacepède, 1803, whereas the latter had more hepatic trypsin-like activity than the former. The peak of activity of the three enzymes in H. auroguttatus was recorded in the winter and spring. On the other hand, P. maculatus tended to have the more prominent peptidase and β-glucosidase activity in the summer, and the smallest in the winter. The intestine of H. auroguttatus had higher enzymatic (trypsin, chymotrypsin and β-glucosidase activity than the stomach and the liver. For P. maculatus, the highest β-glucosidase activity was found in the liver. The enzymatic activity of H. aurogutattus did not differ between lotic and lentic systems, whereas P. maculatus had comparatively higher stomach and hepatic trypsin levels and hepatic chymotrypsin-like activities in the reservoir than down in the river. These findings indicate that, in H. auroguttatus, most digestive activity occurs in the intestine, which is long and adapted for the digestion of bottom-river vegetable matter and detritus. The seasons and the type of the system (lentic vs. lotic seem to affect the enzymatic activity for these two species differently, a likely consequence of their different lifestyles.

  3. The enzymatic activity of the VEGFR2 receptor for the biosynthesis of dinucleoside polyphosphates.

    Science.gov (United States)

    Jankowski, Vera; Schulz, Anna; Kretschmer, Axel; Mischak, Harald; Boehringer, Falko; van der Giet, Markus; Janke, Doreen; Schuchardt, Mirjam; Herwig, Ralf; Zidek, Walter; Jankowski, Joachim

    2013-09-01

    The group of dinucleoside polyphosphates encompasses a large number of molecules consisting of two nucleosides which are connected by a phosphate chain of variable length. While the receptors activated by dinucleoside polyphosphates as well as their degradation have been studied in detail, its biosynthesis has not been elucidated so far. Since endothelial cells released the dinucleoside polyphosphate uridine adenosine tetraphosphate (Up4A), we tested cytosolic proteins of human endothelial cells obtained from dermal vessels elicited for enzymatic activity. When incubated with ADP and UDP, these cells showed increasing concentrations of Up4A. The underlying enzyme was isolated by chromatography and the mass spectrometric analysis revealed that the enzymatic activity was caused by the vascular endothelial growth factor receptor 2 (VEGFR2). Since VEGFR2 but neither VEGFR1 nor VEGFR3 were capable to synthesise dinucleoside polyphosphates, Tyr-1175 of VEGFR2 is most likely essential for the enzymatic activity of interest. Further, VEGFR2-containing cells like HepG2, THP-1 and RAW264.7 were capable of synthesising dinucleoside polyphosphates. VEGFR2-transfected HEK 293T/17 but not native HEK 293T/17 cells synthesised dinucleoside polyphosphates in vivo too. The simultaneous biosynthesis of dinucleoside polyphosphates could amplify the response to VEGF, since dinucleoside polyphosphates induce cellular growth via P2Y purinergic receptors. Thus the biosynthesis of dinucleoside polyphosphates by VEGFR2 may enhance the proliferative response to VEGF. Given that VEGFR2 is primarily expressed in endothelial cells, the biosynthesis of dinucleoside polyphosphates is mainly located in the vascular system. Since the vasculature is also the main site of action of dinucleoside polyphosphates, activating vascular purinoceptors, blood vessels appear as an autocrine system with respect to dinucleoside polyphosphates. We conclude that VEGFR2 receptor is capable of synthesising

  4. Enzymatic transesterification of soybean oil with ethanol using lipases immobilized on highly crystalline PVA microspheres

    International Nuclear Information System (INIS)

    Bergamasco, Juliana; Araujo, Marcelo V. de; Vasconcellos, Adriano de; Luizon Filho, Roberto A.; Hatanaka, Rafael R.; Giotto, Marcus V.; Aranda, Donato A.G.; Nery, José G.

    2013-01-01

    Polyvinyl alcohol (PVA) microspheres with different degree of crystallinity were used as solid supports for Rhizomucor miehei lipase immobilization, and the enzyme-PVA complexes were used as biocatalysts for the transesterification of soybean oil to fatty acid ethyl esters (FAEE). The amounts of immobilized enzyme on the polymeric supports were similar for both the amorphous microspheres (PVA4) and the high crystalline microspheres (PVA25). However, the enzymatic activity of the immobilized enzymes was depended on the crystallinity degree of the PVA microspheres: enzymes immobilized on the PVA4 microspheres have shown low enzymatic activity (6.13 U mg −1 ), in comparison with enzymes immobilized on the high crystalline PVA25 microspheres (149.15 U mg −1 ). A synergistic effect was observed for the enzyme-PVA25 complex during the transesterification reaction of soybean oil to FAEE: transesterification reactions with free enzyme with the equivalent amount of enzyme that were immobilized onto the PVA25 microspheres (5.4 U) have yielded only 20% of FAEE, reactions with the pure highly crystalline microsphere PVA25 have not yielded FAEE, however reactions with the enzyme-PVA25 complexes have yielded 66.3% of FAEE. This synergistic effect of an immobilized enzyme on a polymeric support has not been observed before for transesterification reaction of triacylglycerides into FAEE. Based on ATR-FTIR, 23 Na- and 13 C-NMR-MAS spectroscopic data and the interaction of the polymeric network intermolecular hydrogen bonds with the lipases residual amino acids a possible explanation for this synergistic effect is provided. Highlights: • Rhizomucor miehei lipase was immobilized on PVA microspheres (PVA4, PVA12, PVA25). • Polymer-enzyme complex was characterized by XDR, SEM, ATR-FTIR, 13 C-CPMAS-NMR, 23 Na-MAS-NMR. • Polymer-enzymes (PVA12 and PVA25) enzymes yielded considerable amount of ethyl esters. • Synergistic effect was observed for the polymer-enzyme complexes

  5. EPSPS variability, gene expression, and enzymatic activity in glyphosate-resistant biotypes of Digitaria insularis.

    Science.gov (United States)

    Galeano, E; Barroso, A A M; Vasconcelos, T S; López-Rubio, A; Albrecht, A J P; Victoria Filho, R; Carrer, H

    2016-08-12

    Weed resistance to herbicides is a natural phenomenon that exerts selection on individuals in a population. In Brazil, glyphosate resistance was recently detected in Digitaria insularis. The objective of this study was to elucidate mechanisms of weed resistance in this plant, including genetic variability, allelism, amino acid substitutions, gene expression, and enzymatic activity levels. Most of these have not previously been studied in this species. D. insularis DNA sequences were used to analyze genetic variability. cDNA from resistant and susceptible plants was used to identify mutations, alleles, and 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) expression, using real-time quantitative reverse transcription-polymerase chain reaction. In addition, EPSPS activity was measured. We found a decrease in genetic variability between populations related to glyphosate application. Substitutions from proline to threonine and tyrosine to cysteine led to a decrease in EPSPS affinity for the glyphosate. In addition, the EPSPS enzymatic activity was slightly higher in resistant plants, whereas EPSPS gene expression was almost identical in both biotypes, suggesting feedback regulation at different levels. To conclude, our results suggest new molecular mechanisms used by D. insularis to increase glyphosate resistance.

  6. Effects of lead contamination on soil enzymatic activities, microbial biomass, and rice physiological indices in soil-lead-rice (Oryza sativa L.) system.

    Science.gov (United States)

    Zeng, Lu S; Liao, Min; Chen, Cheng L; Huang, Chang Y

    2007-05-01

    The effect of lead (Pb) treatment on the soil enzymatic activities, soil microbial biomass, rice physiological indices and rice biomass were studied in a greenhouse pot experiment. Six levels of Pb viz. 0(CK), 100, 300, 500, 700, 900 mg/kg soil were applied in two types of paddy soils. The results showed that Pb treatment had a stimulating effect on soil enzymatic activities and microbial biomass carbon (Cmic) at low concentration and an inhibitory influence at higher concentration. The degree of influence on enzymatic activities and Cmic by Pb was related to the clay and organic matter contents of the soils. When the Pb treatment was raised to the level of 500 mg/kg, ecological risk appeared both to soil microorganisms and plants. The results also revealed a consistent trend of increased chlorophyll contents and rice biomass initially, maximum at a certain Pb treatment, and then decreased gradually with the increase in Pb concentration. Pb was effective in inducing proline accumulation and its toxicity causes oxidative stress in rice plants. Therefore, it was concluded that soil enzymatic activities, Cmic and rice physiological indices, could be sensitive indicators to reflect environmental stress in soil-lead-rice system.

  7. Effects of Polyelectrolyte Complex Micelles and Their Components on the Enzymatic Activity of Lipase

    NARCIS (Netherlands)

    Lindhoud, Saskia; Norde, Willem; Stuart, Martien Cohen

    2010-01-01

    The enzymatic activity of Hi-lipase embedded in complexes of poly-2-methylvinylpyridinium-co-poly(ethylene oxide) (P2MVP(41)-PEG(205)) and poly(acrylic acid)(PAA(139)) is studied as a function of the PAA(139) + P2MVP(41) - PEO(205) complex composition. The measurements revealed that there are

  8. Amide group anchored glucose oxidase based anodic catalysts for high performance enzymatic biofuel cell

    Science.gov (United States)

    Chung, Yongjin; Ahn, Yeonjoo; Kim, Do-Heyoung; Kwon, Yongchai

    2017-01-01

    A new enzyme catalyst is formed by fabricating gold nano particle (GNP)-glucose oxidase (GOx) clusters that are then attached to polyethyleneimine (PEI) and carbon nanotube (CNT) with cross-linkable terephthalaldehyde (TPA) (TPA/[CNT/PEI/GOx-GNP]). Especially, amide bonds belonging to TPA play an anchor role for incorporating rigid bonding among GNP, GOx and CNT/PEI, while middle size GNP is well bonded with thiol group of GOx to form strong GNP-GOx cluster. Those bonds are identified by chemical and electrochemical characterizations like XPS and cyclic voltammogram. The anchording effect of amide bonds induces fast electron transfer and strong chemical bonding, resulting in enhancements in (i) catalytic activity, (ii) amount of immobilized GOx and (ii) performance of enzymatic biofuel cell (EBC) including the catalyst. Regarding the catalytic activity, the TPA/[CNT/PEI/GOx-GNP] produces high electron transfer rate constant (6 s-1), high glucose sensitivity (68 μA mM-1 cm-2), high maximum current density (113 μA cm-2), low charge transfer resistance (17.0 Ω cm2) and long-lasting durability while its chemical structure is characterized by XPS confirming large portion of amide bond. In EBC measurement, it has high maximum power density (0.94 mW cm-2) compatible with catalytic acitivity measurements.

  9. Impacts of dissolved organic matter on aqueous behavior of nano/micron-titanium nitride and their induced enzymatic/non-enzymatic antioxidant activities in Scenedesmus obliquus.

    Science.gov (United States)

    Zhang, Xin; Wang, Zhuang; Wang, Se; Fang, Hao; Zhang, Fan; Wang, De-Gao

    2017-01-02

    Freshwater dispersion stability and ecotoxicological effects of titanium nitride (TiN) with particle size of 20 nm, 50 nm, and 2-10 μm in the presence of dissolved organic matter (DOM) at various concentrations were studied. The TiN particles that had a more negative zeta potential and smaller hydrodynamic size showed more stable dispersion in an aqueous medium when DOM was present than when DOM was absent. Biochemical assays indicated that relative to the control, the TiN particles in the presence of DOM alleviated to some extent the antioxidative stress enzyme activity in Scenedesmus obliquus. In addition, it was found that the TiN with a primary size of 50 nm at a high concentration presented a significant impact on non-enzymatic antioxidant defense in algal cells.

  10. Three enzymatically active neurotoxins of Clostridium botulinum strain Af84: BoNT/A2, /F4, and /F5.

    Science.gov (United States)

    Kalb, Suzanne R; Baudys, Jakub; Smith, Theresa J; Smith, Leonard A; Barr, John R

    2014-04-01

    Botulinum neurotoxins (BoNTs) are produced by various species of clostridia and are potent neurotoxins which cause the disease botulism, by cleaving proteins needed for successful nerve transmission. There are currently seven confirmed serotypes of BoNTs, labeled A-G, and toxin-producing clostridia typically only produce one serotype of BoNT. There are a few strains (bivalent strains) which are known to produce more than one serotype of BoNT, producing either both BoNT/A and /B, BoNT/A and /F, or BoNT/B and /F, designated as Ab, Ba, Af, or Bf. Recently, it was reported that Clostridium botulinum strain Af84 has three neurotoxin gene clusters: bont/A2, bont/F4, and bont/F5. This was the first report of a clostridial organism containing more than two neurotoxin gene clusters. Using a mass spectrometry based proteomics approach, we report here that all three neurotoxins, BoNT/A2, /F4, and /F5, are produced by C. botulinum Af84. Label free MS(E) quantification of the three toxins indicated that toxin composition is 88% BoNT/A2, 1% BoNT/F4, and 11% BoNT/F5. The enzymatic activity of all three neurotoxins was assessed by examining the enzymatic activity of the neurotoxins upon peptide substrates, which mimic the toxins' natural targets, and monitoring cleavage of the substrates by mass spectrometry. We determined that all three neurotoxins are enzymatically active. This is the first report of three enzymatically active neurotoxins produced in a single strain of Clostridium botulinum.

  11. Blood parameters and enzymatic and oxidative activity in the liver of chickens fed with calcium anacardate

    Directory of Open Access Journals (Sweden)

    Carlos Eduardo Braga Cruz

    Full Text Available ABSTRACT The aim of this research was to evaluate the inclusion of calcium anacardate (CAC as a source of anacardic acid in the diet of broiler chickens on blood parameters, and enzymatic and oxidative activity in the liver. A total of 840 male chicks, one day old, were kept in a completely randomised experimental design, with six treatments and seven replications of 20 birds, totalling 140 birds per treatment. The treatments consisted of feed without the addition of growth promoter (GP, feed with GP, and feed with no GP and the addition of CAC at levels of 0.25, 0.50, 0.75 and 1%. The biochemical blood variables to be analysed were uric acid, total cholesterol, HDL, LDL, creatinine, AST, ALT, triglycerides, total erythrocytes, haemoglobin, haematocrit, mean corpuscular volume, corpuscular haemoglobin concentration, total plasma protein, total leukocytes, heterophils, lymphocytes, platelets and heterophil/lymphocyte ratio. The concentrations of superoxide dismutase, glutathione peroxidase and malondialdehyde were analysed for the enzymatic and oxidative parameters in the liver. There were no significant differences between treatments in the blood parameters or the enzymatic and oxidative activity in the liver of the chickens, demonstrating that the use of calcium anacardate as a source of anacardic acid is non-toxic, and does not affect these parameters.

  12. Blocked Enzymatic Etching of Gold Nanorods: Application to Colorimetric Detection of Acetylcholinesterase Activity and Its Inhibitors.

    Science.gov (United States)

    Saa, Laura; Grinyte, Ruta; Sánchez-Iglesias, Ana; Liz-Marzán, Luis M; Pavlov, Valeri

    2016-05-04

    The anisotropic morphology of gold nanorods (AuNRs) has been shown to lead to nonuniform ligand distribution and preferential etching through their tips. We have recently demonstrated that this effect can be achieved by biocatalytic oxidation with hydrogen peroxide, catalyzed by the enzyme horseradish peroxidase (HRP). We report here that modification of AuNRs with thiol-containing organic molecules such as glutathione and thiocholine hinders enzymatic AuNR etching. Higher concentrations of thiol-containing molecules in the reaction mixture gradually decrease the rate of enzymatic etching, which can be monitored by UV-vis spectroscopy through changes in the AuNR longitudinal plasmon band. This effect can be applied to develop novel optical assays for acetylcholinesterase (AChE) activity. The biocatalytic hydrolysis of acetylthiocholine by AChE yields thiocholine, which prevents enzymatic AuNR etching in the presence of HRP. Additionally, the same bioassay can be used for the detection of nanomolar concentrations of AChE inhibitors such as paraoxon and galanthamine.

  13. Highly selective apo-arginase based method for sensitive enzymatic assay of manganese (II) and cobalt (II) ions

    Science.gov (United States)

    Stasyuk, Nataliya; Gayda, Galina; Zakalskiy, Andriy; Zakalska, Oksana; Errachid, Abdelhamid; Gonchar, Mykhailo

    2018-03-01

    A novel enzymatic method of manganese (II) and cobalt (II) ions assay, based on using apo-enzyme of Mn2 +-dependent recombinant arginase I (arginase) and 2,3-butanedione monoxime (DMO) as a chemical reagent is proposed. The principle of the method is the evaluation of the activity of L-arginine-hydrolyzing of arginase holoenzyme after the specific binding of Mn2 + or Co2 + with apo-arginase. Urea, which is the product of enzymatic hydrolysis of L-arginine (Arg), reacts with DMO and the resulted compound is detected by both fluorometry and visual spectrophotometry. Thus, the content of metal ions in the tested samples can be determined by measuring the level of urea generated after enzymatic hydrolysis of Arg by reconstructed arginase holoenzyme in the presence of tested metal ions. The linearity range of the fluorometric apo-arginase-DMO method in the case of Mn2 + assay is from 4 pM to 1.10 nM with a limit of detection of 1 pM Mn2 +, whereas the linearity range of the present method in the case of Co2 + assay is from 8 pM to 45 nM with a limit of detection of 2.5 pM Co2 +. The proposed method being highly sensitive, selective, valid and low-cost, may be useful to monitor Mn2 + and Co2 + content in clinical laboratories, food industry and environmental control service.

  14. Contrasting effects of untreated textile wastewater onto the soil available nitrogen-phosphorus and enzymatic activities in aridisol.

    Science.gov (United States)

    Arif, Muhammad Saleem; Riaz, Muhammad; Shahzad, Sher Muhammad; Yasmeen, Tahira; Buttler, Alexandre; Garcıa-Gil, Juan Carlos; Roohi, Mahnaz; Rasool, Akhtar

    2016-02-01

    Water shortage and soil qualitative degradation are significant environmental problems in arid and semi-arid regions of the world. The increasing demand for water in agriculture and industry has resulted in the emergence of wastewater use as an alternative in these areas. Textile wastewater is produced in surplus amounts which poses threat to the environment as well as associated flora and fauna. A 60-day incubation study was performed to assess the effects of untreated textile wastewater at 0, 25, 50, 75, and 100% dilution levels on the physico-chemical and some microbial and enzymatic properties of an aridisol soil. The addition of textile wastewater provoked a significant change in soil pH and electrical conductivity and soil dehydrogenase and urease activities compared to the distilled-water treated control soil. Moreover, compared to the control treatment, soil phosphomonoesterase activity was significantly increased from 25 to 75% application rates, but decreased at 100% textile wastewater application rate. Total and available soil N contents increased significantly in response to application of textile wastewater. Despite significant increases in the soil total P contents after the addition of textile wastewater, soil available P content decreased with increasing concentration of wastewater. Changes in soil nutrient contents and related enzymatic activities suggested a dynamic match between substrate availability and soil N and P contents. Aridisols have high fixation and low P availability, application of textile wastewater to such soils should be considered only after careful assessment.

  15. New Biocatalyst with Multiple Enzymatic Activities for Treatment of Complex Food Wastewaters

    Directory of Open Access Journals (Sweden)

    Olga Senko

    2008-01-01

    Full Text Available The cells of filamentous fungus R. oryzae entrapped in the polyvinyl alcohol cryogelare capable of producing various extracellular hydrolytic enzymes (proteases, amylases, lipases and are used for the treatment of complex wastewaters of food industry. Five types of media simulating the wastewater of various food enterprises were treated under batch conditions for 600 h. Fats containing mostly residues of unsaturated fatty acids, as well as casein, glucose, sucrose, starch, soybean flour and various salts were the main components of the treated wastewaters. The immobilized cells concurrently possessed lipolytic, amylolytic and proteolytic activities. The level of each enzymatic activity depended on the wastewater content. The physiological state of immobilized cells was monitored by bioluminescent method. The intracellular adenosine triphosphate (ATP concentration determined in the granules with immobilized cells was high enough and almost constant for all the period of biocatalyst application confirming thereby the active metabolic state of the cells. The study of mechanical strength of biocatalyst granules allowed revealing the differences in the values of modulus of biocatalyst elasticity at the beginning and at the end of its use for the wastewater treatment. The decrease in chemical oxygen demand of the tested media after their processing by immobilized biocatalyst was 68–79 % for one working cycle.

  16. A Highly Sensitive Electrochemical Glucose Sensor By Nickel-Epoxy Electrode With Non-Enzymatic Sensor

    Directory of Open Access Journals (Sweden)

    Riyanto Riyanto

    2016-03-01

    Full Text Available The preparation of new sensor for glucose was based on the fact that glucose can be determined by non-enzymatic glucose oxidase. The Ni metals (99.98% purity, 0.5 mm thick, Aldrich Chemical Company was used to prepare Ni-Epoxy electrode. The Ni-epoxy electrodes were prepared in square cut of 1 cm and 1 mm by length and wide respectively. The Ni metal electrodes were connected to silver wire with silver conducting paint prior covered with epoxy gum. The prepared of nickel-epoxy modified electrode showed outstanding electro catalytic activity toward the oxidation of glucose in alkaline solution. The result from this research are correlation of determination using Nickel-Epoxyelectrode for electroanalysis of glucose in NaOH was R2 = 0.9984. LOQ, LOD and recovery of the Nickel-Epoxy electrode towards glucose were found to be 4.4 μM, 1.48 μM and 98.19%, respectively. The Nickel-Epoxy wire based electrochemical glucose sensor demonstrates good sensitivity, wide linear range, outstanding detection limit, attractive selectivity, good reproducibility, high stability as well as prominent feasibility use of non-enzymatic sensor for monitoring glucose in human urine owing to its advantages of low cost, simple preparation and excellent properties for glucose detection.

  17. Magnetic Fe3S4 nanoparticles with peroxidase-like activity, and their use in a photometric enzymatic glucose assay

    International Nuclear Information System (INIS)

    Ding, Caiping; Yan, Yinghan; Zhang, Cuiling; Xian, Yuezhong; Xiang, Dongshan

    2016-01-01

    Greigite magnetic nanoparticles (Fe 3 S 4 -MNPs) were prepared and reveal a peroxidase-like activity. Kinetic studies revealed a pseudo-enzymatic activity that is much higher than that of other magnetic nanomaterial-based enzyme mimetics. This finding was exploited to design a photometric enzymatic glucose assay based on the formation of H 2 O 2 during enzymatic oxidation of glucose by glucose oxidase, and the formation of a blue product from an enzyme substrate that is catalytically oxidized by H 2 O 2 in the presence of Fe 3 S 4 -MNPs. Glucose can be detected in the 2 to 100 μM concentration range, and the low detection limit is 0.16 μM. The method was applied to quantify glucose in human serum. In our perception, this enzyme mimetic has a large potential in that it may be used in other oxidase based assays, but also in ELISAs. (author)

  18. Effects of Polyelectrolyte Complex Micelles and Their Components on the Enzymatic Activity of Lipase

    NARCIS (Netherlands)

    Lindhoud, Saskia; Norde, Willem; Cohen Stuart, Martinus Abraham

    2010-01-01

    The enzymatic activity of Hl-lipase embedded in complexes of poly-2-methylvinylpyridinium-co-poly(ethylene oxide) (P2MVP41−PEO205) and poly(acrylic acid)(PAA139) is studied as a function of the PAA139 + P2MVP41−PEO205 complex composition. The measurements revealed that there are several factors that

  19. Enzymatic digestive activity and absorption efficiency in Tagelus dombeii upon Alexandrium catenella exposure

    Science.gov (United States)

    Fernández-Reiriz, M. J.; Navarro, J. M.; Cisternas, B. A.; Babarro, J. M. F.; Labarta, U.

    2013-12-01

    We analyzed absorption efficiency (AE) and digestive enzyme activity (amylase, cellulase complex, and laminarinase) of the infaunal bivalve Tagelus dombeii originating from two geographic sites, Corral-Valdivia and Melinka-Aysén, which have different long-term paralytic shellfish poisoning (PSP) exposure rates. We report the effects of past feeding history (origin) on T. dombeii exposed to a mixed diet containing the toxic dinoflagellate Alexandrium catenella and another dinoflagellate-free control diet over a 12-day period in the laboratory. Absorption efficiency values of T. dombeii individuals that experienced PSP exposure in their habitat (Melinka-Aysén) remained unchanged during exposure to toxic food in the laboratory. In contrast, T. dombeii from a non-PSP exposure field site (Corral-Valdivia) showed a significant reduction in AE with toxic exposure time. This study established that the amylase and cellulase complexes were the most important enzymes in the digestive glands of Tagelus from both sites. The temporal evolution of enzymatic activity under toxic diet was fitted to exponential (amylase and cellulase) and to a logarithmic (laminarinase) models. In all fits, we found significant effect of origin in the model parameters. At the beginning of the experiment, higher enzymatic activity was observed for clams from Corral-Valdivia. The amylase activity decreased with time exposure for individuals from Corral and increased for individuals from Melinka. Cellulase activity did not vary over time for clams from Corral, but increased for individuals from Melinka and laminarinase activity decreased over time for individuals from Corral and remained unchanged over time for Melinka. A feeding history of exposure to the dinoflagellate A. catenella was reflected in the digestive responses of both T. dombeii populations.

  20. Isoprene Production on Enzymatic Hydrolysate of Peanut Hull Using Different Pretreatment Methods

    Directory of Open Access Journals (Sweden)

    Sumeng Wang

    2016-01-01

    Full Text Available The present study is about the use of peanut hull for isoprene production. In this study, two pretreatment methods, hydrogen peroxide-acetic acid (HPAC and popping, were employed prior to enzymatic hydrolysis, which could destroy the lignocellulosic structure and accordingly improve the efficiency of enzymatic hydrolysis. It is proven that the isoprene production on enzymatic hydrolysate with HPAC pretreatment is about 1.9-fold higher than that of popping pretreatment. Moreover, through High Performance Liquid Chromatography (HPLC analysis, the amount and category of inhibitors such as formic acid, acetic acid, and HMF were assayed and were varied in different enzymatic hydrolysates, which may be the reason leading to a decrease in isoprene production during fermentation. To further increase the isoprene yield, the enzymatic hydrolysate of HPAC was detoxified by activated carbon. As a result, using the detoxified enzymatic hydrolysate as the carbon source, the engineered strain YJM21 could accumulate 297.5 mg/L isoprene, which accounted for about 90% of isoprene production by YJM21 fermented on pure glucose (338.6 mg/L. This work is thought to be the first attempt on isoprene production by E. coli using peanut hull as the feedstock. More importantly, it also shows the prospect of peanut hull to be considered as an alternative feedstock for bio-based chemicals or biofuels production due to its easy access and high polysaccharide content.

  1. High glucose recovery from direct enzymatic hydrolysis of bisulfite-pretreatment on non-detoxified furfural residues.

    Science.gov (United States)

    Xing, Yang; Bu, Lingxi; Sun, Dafeng; Liu, Zhiping; Liu, Shijie; Jiang, Jianxin

    2015-10-01

    This study reports four schemes to pretreat wet furfural residues (FRs) with sodium bisulfite for production of fermentable sugar. The results showed that non-detoxified FRs (pH 2-3) had great potential to lower the cost of bioconversion. The optimal process was that unwashed FRs were first pretreated with bisulfite, and the whole slurry was then directly used for enzymatic hydrolysis. A maximum glucose yield of 99.4% was achieved from substrates pretreated with 0.1 g NaHSO3/g dry substrate (DS), at a relatively low temperature of 100 °C for 3 h. Compared with raw material, enzymatic hydrolysis at a high-solid of 16.5% (w/w) specifically showed more excellent performance with bisulfite treated FRs. Direct bisulfite pretreatment improved the accessibility of substrates and the total glucose recovery. Lignosulfonate in the non-detoxified slurry decreased the non-productive adsorption of cellulase on the substrate, thus improving enzymatic hydrolysis. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Sequence homolog-based molecular engineering for shifting the enzymatic pH optimum

    Directory of Open Access Journals (Sweden)

    Fuqiang Ma

    2016-09-01

    Full Text Available Cell-free synthetic biology system organizes multiple enzymes (parts from different sources to implement unnatural catalytic functions. Highly adaption between the catalytic parts is crucial for building up efficient artificial biosynthetic systems. Protein engineering is a powerful technology to tailor various enzymatic properties including catalytic efficiency, substrate specificity, temperature adaptation and even achieve new catalytic functions. However, altering enzymatic pH optimum still remains a challenging task. In this study, we proposed a novel sequence homolog-based protein engineering strategy for shifting the enzymatic pH optimum based on statistical analyses of sequence-function relationship data of enzyme family. By two statistical procedures, artificial neural networks (ANNs and least absolute shrinkage and selection operator (Lasso, five amino acids in GH11 xylanase family were identified to be related to the evolution of enzymatic pH optimum. Site-directed mutagenesis of a thermophilic xylanase from Caldicellulosiruptor bescii revealed that four out of five mutations could alter the enzymatic pH optima toward acidic condition without compromising the catalytic activity and thermostability. Combination of the positive mutants resulted in the best mutant M31 that decreased its pH optimum for 1.5 units and showed increased catalytic activity at pH < 5.0 compared to the wild-type enzyme. Structure analysis revealed that all the mutations are distant from the active center, which may be difficult to be identified by conventional rational design strategy. Interestingly, the four mutation sites are clustered at a certain region of the enzyme, suggesting a potential “hot zone” for regulating the pH optima of xylanases. This study provides an efficient method of modulating enzymatic pH optima based on statistical sequence analyses, which can facilitate the design and optimization of suitable catalytic parts for the construction

  3. Activation of Hsp90 Enzymatic Activity and Conformational Dynamics through Rationally Designed Allosteric Ligands.

    Science.gov (United States)

    Sattin, Sara; Tao, Jiahui; Vettoretti, Gerolamo; Moroni, Elisabetta; Pennati, Marzia; Lopergolo, Alessia; Morelli, Laura; Bugatti, Antonella; Zuehlke, Abbey; Moses, Mike; Prince, Thomas; Kijima, Toshiki; Beebe, Kristin; Rusnati, Marco; Neckers, Len; Zaffaroni, Nadia; Agard, David A; Bernardi, Anna; Colombo, Giorgio

    2015-09-21

    Hsp90 is a molecular chaperone of pivotal importance for multiple cell pathways. ATP-regulated internal dynamics are critical for its function and current pharmacological approaches block the chaperone with ATP-competitive inhibitors. Herein, a general approach to perturb Hsp90 through design of new allosteric ligands aimed at modulating its functional dynamics is proposed. Based on the characterization of a first set of 2-phenylbenzofurans showing stimulatory effects on Hsp90 ATPase and conformational dynamics, new ligands were developed that activate Hsp90 by targeting an allosteric site, located 65 Å from the active site. Specifically, analysis of protein responses to first-generation activators was exploited to guide the design of novel derivatives with improved ability to stimulate ATP hydrolysis. The molecules' effects on Hsp90 enzymatic, conformational, co-chaperone and client-binding properties were characterized through biochemical, biophysical and cellular approaches. These designed probes act as allosteric activators of the chaperone and affect the viability of cancer cell lines for which proper functioning of Hsp90 is necessary. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Analysis of Ethyl Acetate Extract of Enzymatic Hydrolysate from High Purity Oleuropein and DPPH Radical Scavenging Capacity

    Science.gov (United States)

    Yuan, Jiaojiao; Li, Bing; Qin, Frank G. F.; Tu, Junling

    2018-01-01

    High purify oleuropein (81.04% OL) was hydrolyzed by hemicellulase and phenols was existed in the ethyl acetate extract of enzymatic hydrolysate (EAE). The results presented that there were hydroxytyrosol (HT), tyrosol, caffeic acid, 3,4-dihydroxybenzoic acid, 3,4-dihydroxy phenylacetic acid in EAE by HPLC, and HT content was 19.36%. Antioxidant activities (DPPH radical scavenging capacity) were all added as the samples concentration increased, and dose-effect relationships also existed. HT possessed the highest DPPH radical scavenging capacity, followed by Vc, and eugenol, OL, caffeic acid, 3,4-dihydroxy phenylacetic acid and 3,4-dihydroxybenzoic acid.

  5. Glycosylation site-targeted PEGylation of glucose oxidase retains native enzymatic activity.

    Science.gov (United States)

    Ritter, Dustin W; Roberts, Jason R; McShane, Michael J

    2013-04-10

    Targeted PEGylation of glucose oxidase at its glycosylation sites was investigated to determine the effect on enzymatic activity, as well as the bioconjugate's potential in an optical biosensing assay. Methoxy-poly(ethylene glycol)-hydrazide (4.5kDa) was covalently coupled to periodate-oxidized glycosylation sites of glucose oxidase from Aspergillus niger. The bioconjugate was characterized using gel electrophoresis, liquid chromatography, mass spectrometry, and dynamic light scattering. Gel electrophoresis data showed that the PEGylation protocol resulted in a drastic increase (ca. 100kDa) in the apparent molecular mass of the protein subunit, with complete conversion to the bioconjugate; liquid chromatography data corroborated this large increase in molecular size. Mass spectrometry data proved that the extent of PEGylation was six poly(ethylene glycol) chains per glucose oxidase dimer. Dynamic light scattering data indicated the absence of higher-order oligomers in the PEGylated GOx sample. To assess stability, enzymatic activity assays were performed in triplicate at multiple time points over the course of 29 days in the absence of glucose, as well as before and after exposure to 5% w/v glucose for 24h. At a confidence level of 95%, the bioconjugate's performance was statistically equivalent to native glucose oxidase in terms of activity retention over the 29 day time period, as well as following the 24h glucose exposure. Finally, the bioconjugate was entrapped within a poly(2-hydroxyethyl methacrylate) hydrogel containing an oxygen-sensitive phosphor, and the construct was shown to respond approximately linearly with a 220±73% signal change (n=4, 95% confidence interval) over the physiologically-relevant glucose range (i.e., 0-400mg/dL); to our knowledge, this represents the first demonstration of PEGylated glucose oxidase incorporated into an optical biosensing assay. Copyright © 2013 Elsevier Inc. All rights reserved.

  6. Modulation of Enzymatic Activities of Dual Functional Peroxiredoxin by Gamma Irradiation

    International Nuclear Information System (INIS)

    Hong, Sung Hyun; Lee, Seung Sik; Park, Chul Hong; Chung, Byung Yeoup

    2012-01-01

    Recently, enzymes have frequently been used as catalysts in various bio-industrial, commercial, and pharmaceutical applications, because they are more stable, more efficient, and less toxic than the synthetic catalysts. However, one of their major disadvantages is their low thermostability, which leads the researchers to develop new forms of industrially important enzymes with increased resistance to inactivation and aggregation. This study describes a strategy for modifying the molecular chaperone activity of peroxiredoxin (Prx) by using gamma irradiation. Prxs are a ubiquitous family of antioxidant enzymes. Upon oxidation of their peroxidatic Cys, the molecules undergo a structural conversion from a low-molecular-weight (LMW) species acting as a peroxidase to a high-molecular-weight (HMW) complex functioning as a chaperone. In the present study, we examined the effect of gamma irradiation on PP1084 with respect to its protein structure and enzymatic function. The use of gamma irradiation as a physical treatment can increase the cohesive strength of the protein by forming cross-links. The aims of the present work were (1) to improve the chaperone activity of PP1084 by gamma irradiation, (2) to identify the 'optimal' intensity of gamma irradiation, and (3) to investigate the influence of gamma irradiation on protein hydrophobicity as related to chaperone function. Following PP1084 treatment with 30 kGy gamma irradiation, the PP1084 chaperone activity enhanced by about 3-4-fold compared with nonirradiated PP1084, while the peroxidase activity decreased. Ongoing research efforts are addressing the physical modifications of PP1084 protein by gamma irradiation

  7. High Hydrostatic Pressure-Assisted Enzymatic Treatment Improves Antioxidant and Anti-inflammatory Properties of Phosvitin.

    Science.gov (United States)

    Yoo, Heejoo; Bamdad, Fatemeh; Gujral, Naiyana; Suh, Joo-Won; Sunwoo, Hoon

    2017-01-01

    Phosvitin (PV) is a highly-phosphorylated metal-binding protein in egg yolk. Phosphoserine clusters make PV resistant to enzymatic digestion, which might be nutritionally undesirable. This study was designed to determine the effects of high hydrostatic pressure and enzymatic hydrolysis (HHP-EH) on the antioxidant and anti-inflammatory properties of PV hydrolysates (PVHs). PV was hydrolyzed by alcalase, elastase, savinase, thermolysin, and trypsin at 0.1, 50, and 100 MPa pressure levels. PVHs were evaluated for degree of hydrolysis, molecular weight distribution patterns, antioxidant and anti-inflammatory properties in chemical and cellular models. The effect of PVH on gene expression of pro-inflammatory cytokines (TNF-α and IL-1β) was also evaluated using real time-PCR. The hydrolysate with most potent antioxidant and anti-inflammatory properties was subjected to LC-MS/MS analysis to identify the peptide sequence. Hydrolysates produced at 100 MPa exhibited higher degree of hydrolysis and greater reducing power and free radical scavenging activity compared to those obtained at atmospheric pressure. After adjusting the phosphate content, alcalase- and trypsin-digested PVHs showed superior iron chelation capacity (69-73%), regardless of pressure. Both alcalase- and trypsin-digested PVHs significantly inhibited nitric oxide production by RAW264.7 macrophage cells. LPS-stimulated up-regulation of proinflammatory cytokines was also suppressed by alcalase-digested PVH. The HHP-EH method could play a promising role in the production of bioactive peptides from hydrolysis-resistant proteins. HHP-assisted PVH may be useful in preparing a potential pharmaceutical with antioxidant and anti-inflammatory properties. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  8. Lactose hydrolysis in an enzymatic membrane reactor

    Energy Technology Data Exchange (ETDEWEB)

    Mertens, B; Huyghebaert, A

    1987-10-01

    The enzymatic hydrolysis of lactose in whey permeate with subsequent recuperation of Saccharomyces lactis lactase by means of ultrafiltration was investigated. In whey permeate, S. lactis lactase shows maximal activity at pH 6.5; the optimal temperature was found to be 45/sup 0/C and is limited by strong thermal inactivation beyond this temperature. High activity combined with acceptable thermal inactivation (< 10% after 5 h incubation) was established at 30/sup 0/C. S. lactis lactase also displays considerable activity at low temperature (5/sup 0/C). Enzyme stability is reduced drastically by demineralisation: addition of low concentrations of manganese ions (10/sup -3/ M) considerably enhances stability. Using a DDS Lab-Unit 35 fitted with GR61PP polysulphon membranes (cut-off: 20.000), pilot scale experiments were carried out (pH 6.5; 30/sup 0/C) in which whey permeate was hydrolyzed to a degree of hydrolysis of 82% minimum. Enzyme recuperation amounted to 96.5% per batch, all enzyme activity loss being due to thermal inactivation. Microbiological examination of the enzymatic membrane reactor showed that growth of mcicroorganisms can largely be suppressed by working at lower temperature (5/sup 0/C). Eventually, 50 ppm H/sub 2/O/sub 2/ or sterile filtration will adequately solve microbiological problems without affecting enzyme activity.

  9. Encapsulation and covalent binding of molecular payload in enzymatically activated micellar nanocarriers.

    Science.gov (United States)

    Rosenbaum, Ido; Harnoy, Assaf J; Tirosh, Einat; Buzhor, Marina; Segal, Merav; Frid, Liat; Shaharabani, Rona; Avinery, Ram; Beck, Roy; Amir, Roey J

    2015-02-18

    The high selectivity and often-observed overexpression of specific disease-associated enzymes make them extremely attractive for triggering the release of hydrophobic drug or probe molecules from stimuli-responsive micellar nanocarriers. Here we utilized highly modular amphiphilic polymeric hybrids, composed of a linear hydrophilic polyethylene glycol (PEG) and an esterase-responsive hydrophobic dendron, to prepare and study two diverse strategies for loading of enzyme-responsive micelles. In the first type of micelles, hydrophobic coumarin-derived dyes were encapsulated noncovalently inside the hydrophobic core of the micelle, which was composed of lipophilic enzyme-responsive dendrons. In the second type of micellar nanocarrier the hydrophobic molecular cargo was covalently linked to the end-groups of the dendron through enzyme-cleavable bonds. These amphiphilic hybrids self-assembled into micellar nanocarriers with their cargo covalently encapsulated within the hydrophobic core. Both types of micelles were highly responsive toward the activating enzyme and released their molecular cargo upon enzymatic stimulus. Importantly, while faster release was observed with noncovalent encapsulation, higher loading capacity and slower release rate were achieved with covalent encapsulation. Our results clearly indicate the great potential of enzyme-responsive micellar delivery platforms due to the ability to tune their payload capacities and release rates by adjusting the loading strategy.

  10. Enzymatic determination of rare earth elements using pyrophosphatases

    International Nuclear Information System (INIS)

    Shekhovtsova, T.N.; Pirogova, S.V.; Fedorova, O.M.; Dolmanova, I.F.; Bajkov, A.A.

    1993-01-01

    A highly sensitive(determination limit 8x10 -6 -4x10 -4 μ g/m) and selective enzymatic method for determination of rare earth elements has been developed. The method is based on inhibition action of rare earths on the catalytic activity of pyrophosphates isolated from bakery geast and E.Coli. The mechanism of the rare earth element action, corresponding to competitive inhibition, has been established

  11. Enzymatic modification of starch

    DEFF Research Database (Denmark)

    Jensen, Susanne Langgård

    In the food industry approaches for using bioengineering are investigated as alternatives to conventional chemical and physical starch modification techniques in development of starches with specific properties. Enzyme-assisted post-harvest modification is an interesting approach to this, since...... it is considered a clean and energy saving technology. This thesis aimed to investigate the effect of using reaction conditions, simulating an industrial process, for enzymatic treatment of starch with branching enzyme (BE) from Rhodothermus obamensis. Thus treatements were conducted at 70°C using very high...... substrate concentration (30-40% dry matter (DM)) and high enzyme activity (750-2250 BE units (BEU)/g sample). Starches from various botanical sources, representing a broad range of properties, were used as substrates. The effects of the used conditions on the BE-reaction were evaluated by characterization...

  12. DNA-dispersed graphene/NiO hybrid materials for highly sensitive non-enzymatic glucose sensor

    International Nuclear Information System (INIS)

    Lv Wei; Jin Fengmin; Guo Quangui; Yang Quanhong; Kang Feiyu

    2012-01-01

    Highlights: ► We investigated the potential of GNS/NiO/DNA hybrid used as a nonenzymatic sensor. ► DNA is a highly efficient disperse agent for GNS/NiO hybrid than ionic surfactants. ► GNS/NiO/DNA hybrid shows fast electron transfer in the electrochemical reaction. ► GNS/NiO/DNA hybrid shows good detection performance towards glucose. - Abstract: We demonstrate graphene nanosheet/NiO hybrids (GNS/NiO) as the active material for high-performance non-enzymatic glucose sensors. Such sensors are fabricated by DNA-dispersed GNS/NiO suspension deposited on glassy carbon electrodes. ss-DNA shows strong dispersing ability for the GNS/NiO hybrid materials resulting in stable water-dispersible GNS/NiO/DNA hybrids with fully separated layers. The GNS/NiO/DNA hybrids show enhanced electron transfer in the electrocatalytic reaction process, and accordingly, such hybrids modified electrodes show good sensing performance towards glucose and are characterized by large detection ranges, short response periods, low detection limit and high sensitivity and stability.

  13. Chemical interaction of disulfiram with nitrosodimethylamine after in vitro enzymatic activation

    International Nuclear Information System (INIS)

    Tacchi, A.M.; Bertram, B.; Wiessler, M.

    1984-01-01

    The in vitro reaction between disulfiram (DSF) and N-nitroso[ 14 C]dimethylamine [( 14 C]NDMA) was studied. Incubations of DSF with [ 14 C]NDMA were carried out in the presence of rat liver microsomes, control 9000 g (S9) supernatant fraction and phenobarbital-induced S9 fraction. HPLC analysis and liquid scintillation measurement provided evidence for the formation of methyldiethyldithiocarbamate (MeDDTC) as a product of the reaction between diethyldithiocarbamate (DDTC), the main active metabolite of DSF and the 'methyl-cation' released by NDMA after enzymatic activation. The amount of MeDDTC found here was consistent with the rate of oxidation of NDMA to formaldehyde. Scintillation counting confirmed that other radioactive peaks, not due to MeDDTC, were unrelated to the methylation of L-cysteine by [ 14 C]NDMA

  14. Anti-Inflammatory and Antioxidant Properties of Peptides Released from β-Lactoglobulin by High Hydrostatic Pressure-Assisted Enzymatic Hydrolysis.

    Science.gov (United States)

    Bamdad, Fatemeh; Bark, Seonghee; Kwon, Chul Hee; Suh, Joo-Won; Sunwoo, Hoon

    2017-06-07

    β-lactoglobulin hydrolysates (BLGH) have shown antioxidant, antihypertensive, antimicrobial, and opioid activity. In the current study, an innovative combination of high hydrostatic pressure and enzymatic hydrolysis (HHP-EH) was used to increase the yield of short bioactive peptides, and evaluate the anti-inflammatory and antioxidant properties of the BLGH produced by the HHP-EH process. BLG was enzymatically hydrolyzed by different proteases at an enzyme-to-substrate ratio of 1:100 under HHP (100 MPa) and compared with hydrolysates obtained under atmospheric pressure (AP-EH at 0.1 MPa). The degree of hydrolysis (DH), molecular weight distribution, and the antioxidant and anti-inflammatory properties of hydrolysates in chemical and cellular models were evaluated. BLGH obtained under HHP-EH showed higher DH than the hydrolysates obtained under AP-EH. Free radical scavenging and the reducing capacity were also significantly stronger in HHP-BLGH compared to AP-BLGH. The BLGH produced by alcalase (Alc) (BLG-Alc) showed significantly higher antioxidant properties among the six enzymes examined in this study. The anti-inflammatory properties of BLG-HHP-Alc were observed in lipopolysaccharide-stimulated macrophage cells by a lower level of nitric oxide production and the suppression of the synthesis of pro-inflammatory cytokines. Peptide sequencing revealed that 38% of the amino acids in BLG-HHP-Alc are hydrophobic and aromatic residues, which contribute to its anti-inflammatory properties. Enzymatic hydrolysis of BLG under HHP produces a higher yield of short bioactive peptides with potential antioxidant and anti-inflammatory effects.

  15. Enzymatic Conversion of CO2 to Bicarbonate in Functionalized Mesoporous Silica

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Yuehua; Chen, Baowei; Qi, Wen N.; Li, Xiaolin; Shin, Yongsoon; Lei, Chenghong; Liu, Jun

    2012-05-01

    We report here that carbonic anhydrase (CA), the fastest enzyme that can covert carbon dioxide to bicarbonate, can be spontaneously entrapped in functionalized mesoporous silica (FMS) with super-high loading density (up to 0.5 mg of protein/mg of FMS) due to the dominant electrostatic interaction. The binding of CA to HOOC-FMS can result in the protein’s conformational change comparing to the enzyme free in solution, but can be overcome with increased protein loading density. The higher the protein loading density, the less conformational change, hence the higher enzymatic activity and the higher enzyme immobilization efficiency. The electrostatically bound CA can be released by changing pH. The released enzyme still displayed the native conformational structure and the same high enzymatic activity as that prior to the enzyme entrapment. This work opens up a new approach converting carbon dioxide to biocarbonate in a biomimetic nanoconfiguration that can be integrated with the other part of biosynthesis process for the assimilation of carbon dioxide.

  16. Fluoranthene induced changes in photosynthetic pigments, biochemical compounds and enzymatic activities in two microalgal species: Chlorella vulgaris Beijerinck and Desmodesmus subspicatus Chodat

    Directory of Open Access Journals (Sweden)

    Miral Patel

    2014-02-01

    Full Text Available The photosynthetic pigments, biochemical and enzymatic activities in two freshwater microalgal species, Chlorella vulgaris and Desmodesmus subspicatus at different fluoranthene concentrations were compared with the control conditions. During 16-days of incubation period when treated with fluoranthene, both microalgal species exhibited variable amount of photosynthetic pigment, biochemical compounds and enzymatic activities. The addition of fluoranthene at concentrations ranged from 1.5 mg l-1; to 10 mg l-1; to microalgal cultures led to changes in all different metabolites but the patterns varied from species to species. Among the two species tested, pigment, biochemical and enzymatic contents were remarkably declined from 7 % to 95% in C. vulgaris. Moreover, all metabolites in D. subspicatus also diminishing significantly by 3% to 88% of fluoranthene doses (10ppm. These results suggest that fluoranthene-induced changes of pigments, biochemical and enzymatic variations in test microalgae, D. subspicatus and C. vulgaris, might reveal its resistance and ability to metabolize PAHs. At the same time, the PAH impact changes on different metabolic activities were higher at 12 and 16 days than at 4 and 8 days in treated microalgae. DOI: http://dx.doi.org/10.3126/ije.v3i1.9941 International Journal of Environment Vol.3(1 2014: 41-55

  17. Enzymatic Browning: a practical class

    Directory of Open Access Journals (Sweden)

    Maria Teresa Pedrosa Silva Clerici

    2014-10-01

    Full Text Available This paper presents a practical class about the enzymes polyphenol oxidases, which have been shown to be responsible for the enzymatic browning of fruits and vegetables. Vegetables samples were submitted to enzymatic inactivation process with chemical reagents, as well as by bleaching methods of applying heat by conventional oven and microwave oven. Process efficiency was assessed qualitatively by both observing the guaiacol peroxidase activity and after the storage period under refrigeration or freezing. The practical results obtained in this class allow exploring multidisciplinary knowledge in food science, with practical applications in everyday life.

  18. Positive effects of temperature and growth conditions on enzymatic and antioxidant status in lettuce plants.

    Science.gov (United States)

    Boo, Hee-Ock; Heo, Buk-Gu; Gorinstein, Shela; Chon, Sang-Uk

    2011-10-01

    The contents of two bioactive compounds (polyphenols and flavonoids) and their antioxidant and enzyme activities were determined in the leaves of six lettuce (Latuca sativa L.) cultivars subjected to 4 different day/night temperatures for 6 weeks. The total polyphenol and anthocyanin contents and the corresponding antioxidant activities were the highest at 13/10°C and 20/13°C, followed by 25/20°C and 30/25°C. The enzymatic activities of polyphenol oxidase (PPO) and phenylalanine ammonia-lyase (PAL) were also the highest at low day/night temperatures, but the peroxidase (POD) activity was decreased at low day/night temperatures and increased at high day/night temperatures. The most significant positive correlation existed between anthocyanin content and PPO activity, total polyphenols and their antioxidant activities. The results showed that at relatively low temperatures, lettuce plants have a high antioxidant and enzymatic status. These results provide additional information for the lettuce growers. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  19. E. coli-Derived L-Asparaginase Retains Enzymatic and Cytotoxic Activity In Vitro for Canine and Feline Lymphoma after Cold Storage

    Directory of Open Access Journals (Sweden)

    Jackie M. Wypij

    2013-01-01

    Full Text Available Background. L-asparaginase is effective in treating canine and feline lymphoma, however chemotherapy poses a significant financial cost to veterinary clients, limiting therapy for many pets. Single dose vials result in significant drug wastage, and drug shortages limit consistent availability for pets. Hypothesis. E. coli-derived asparaginase retains enzymatic and antineoplastic activity in canine and feline lymphoma cells after cold storage. Methods. E. coli-derived asparaginase was cold-stored: refrigeration (7–14 days and freezing (14 days–six months, one to three freeze/thaw cycles. Enzymatic activity of asparaginase was measured via a modified asparagine assay. Effects of cold-stored asparaginase on cell proliferation and cytotoxicity were measured in feline (MYA-1, F1B and canine (17–71, OSW lymphoma cells. Results. Cold-stored E. coli-derived asparaginase retains antineoplastic activity in all four cell lines tested. Cold-stored E. coli-derived L-asparaginase depletes asparagine and retains enzymatic activity. Duration of refrigeration, duration of freezing, and number of freeze-thaw cycles have minimal effect on asparaginase enzyme activity. Conclusions and Clinical Importance. This study establishes a scientific basis for long-term cold storage of reconstituted E. coli-derived asparaginase that may result in better utilization of limited drug resources and improve financial feasibility of E. coli-derived asparaginase as a therapeutic option for pets with lymphoma.

  20. Enzymatic cell wall degradation of high-pressure-homogenized tomato puree and its effect on lycopene bioaccessibility.

    Science.gov (United States)

    Palmero, Paola; Colle, Ines; Lemmens, Lien; Panozzo, Agnese; Nguyen, Tuyen Thi My; Hendrickx, Marc; Van Loey, Ann

    2016-01-15

    High-pressure homogenization disrupts cell structures, assisting carotenoid release from the matrix and subsequent micellarization. However, lycopene bioaccessibility of tomato puree upon high-pressure homogenization is limited by the formation of a process-induced barrier. In this context, cell wall-degrading enzymes were applied to hydrolyze the formed barrier and enhance lycopene bioaccessibility. The effectiveness of the enzymes in degrading their corresponding substrates was evaluated (consistency, amount of reducing sugars, molar mass distribution and immunolabeling). An in vitro digestion procedure was applied to evaluate the effect of the enzymatic treatments on lycopene bioaccessibility. Enzymatic treatments with pectinases and cellulase were proved to effectively degrade their corresponding cell wall polymers; however, no further significant increase in lycopene bioaccessibility was obtained. A process-induced barrier consisting of cell wall material is not the only factor governing lycopene bioaccessibility upon high-pressure homogenization. © 2015 Society of Chemical Industry.

  1. Analysis of Enzymatic Activity of Matrix Metalloproteinase (MMP) by Collagen Zymography in Melanoma.

    Science.gov (United States)

    Walia, Vijay; Samuels, Yardena

    2018-01-01

    Protein zymography is the most commonly used technique to study the enzymatic activity of matrix metalloproteinases (MMPs) and their inhibitors. MMPs are proteolytic enzymes that promote extracellular matrix degradation. MMPs are frequently mutated in malignant melanomas as well as other cancers and are linked to increasing incidence of tumor metastasis. Substrate zymography characterizes MMP activity by their ability to degrade preferred substrates. Here we describe the collagen zymography technique to measure the active or latent form of MMPs using MMP-8 as an example, which is a frequently mutated MMP family member in malignant melanomas. The same technique can be used with the modification of substrate to detect metalloproteinase activity of other MMPs. Both wild-type and mutated forms of MMPs can be analyzed using a single gel using this method.

  2. Relationship between Porcine Sperm Motility and Sperm Enzymatic Activity using Paper-based Devices

    Science.gov (United States)

    Matsuura, Koji; Huang, Han-Wei; Chen, Ming-Cheng; Chen, Yu; Cheng, Chao-Min

    2017-04-01

    Mammalian sperm motility has traditionally been analyzed to determine fertility using computer-assisted semen analysis (CASA) systems. To develop low-cost and robust male fertility diagnostics, we created a paper-based MTT assay and used it to estimate motile sperm concentration. When porcine sperm motility was inhibited using sperm enzyme inhibitors for sperm enzymes related to mitochondrial activity and glycolysis, we simultaneously recorded sperm motility and enzymatic reactivity using a portable motility analysis system (iSperm) and a paper-based MTT assay, respectively. When using our paper-based MTT-assay, we calculated the area mean value signal intensity (AMV) to evaluate enzymatic reactivity. Both sperm motility and AMV decreased following treatment with iodoacetamide (IODO) and 3-bromopyruvic acid (3BP), both of which are inhibitors of glycolytic enzymes including glyceraldehyde-3-phosphate dehydrogenase (GAPDH). We found a correlation between recorded motility using iSperm and AMV from our paper-based assay (P Based on this inhibitor study, sperm motility can be estimated using our paper-based MTT-assay.

  3. Enzymatic Activity of the Mycelium Compared with Oospore Development During Infection of Pea Roots by Aphanomyces euteiches

    DEFF Research Database (Denmark)

    Kjøller, Rasmus; Rosendahl, Søren

    1998-01-01

    To describe the disease cycle of the root pathogen Aphanomyces euteiches, enzymatic activity in the mycelium was compared with the development of oospores in pea roots. Plants were inoculated with two zoospore concentrations to achieve different disease levels. Hyphae were stained for fungal...

  4. Highly Branched Bio-Based Unsaturated Polyesters by Enzymatic Polymerization

    Directory of Open Access Journals (Sweden)

    Hiep Dinh Nguyen

    2016-10-01

    Full Text Available A one-pot, enzyme-catalyzed bulk polymerization method for direct production of highly branched polyesters has been developed as an alternative to currently used industrial procedures. Bio-based feed components in the form of glycerol, pentaerythritol, azelaic acid, and tall oil fatty acid (TOFA were polymerized using an immobilized Candida antarctica lipase B (CALB and the potential for an enzymatic synthesis of alkyds was investigated. The developed method enables the use of both glycerol and also pentaerythritol (for the first time as the alcohol source and was found to be very robust. This allows simple variations in the molar mass and structure of the polyester without premature gelation, thus enabling easy tailoring of the branched polyester structure. The postpolymerization crosslinking of the polyesters illustrates their potential as binders in alkyds. The formed films had good UV stability, very high water contact angles of up to 141° and a glass transition temperature that could be controlled through the feed composition.

  5. The diversity, extracellular enzymatic activities and photoprotective compounds of yeasts isolated in Antarctica

    Directory of Open Access Journals (Sweden)

    Aline B. M Vaz

    2011-09-01

    Full Text Available The diversity of yeasts collected from different sites in Antarctica (Admiralty Bay, King George Island and Port Foster Bay and Deception Island and their ability to produce extracellular enzymes and mycosporines were studied. Samples were collected during the austral summer season, between November 2006 and January 2007, from the rhizosphere of Deschampsia antarctica, ornithogenic (penguin guano soil, soil, marine and lake sediments, marine water and freshwater from lakes. A total of 89 isolates belonging to the following genera were recovered: Bensingtonia, Candida, Cryptococcus, Debaryomyces, Dioszegia, Exophiala, Filobasidium, Issatchenkia (Pichia, Kodamaea, Leucosporidium, Leucosporidiella, Metschnikowia, Nadsonia, Pichia, Rhodotorula, and Sporidiobolus, and the yeast-like fungi Aureobasidium, Leuconeurospora and Microglossum. Cryptococcus victoriae was the most frequently identified species. Several species isolated in our study have been previously reported to be Antarctic psychophilic yeasts, including Cr. antarcticus, Cr. victoriae, Dioszegia hungarica and Leucosporidium scottii. The cosmopolitan yeast species A. pullulans, C. zeylanoides, D. hansenii, I. orientalis, K. ohmeri, P. guilliermondii, Rh. mucilaginosa, and S. salmonicolor were also isolated. Five possible new species were identified. Sixty percent of the yeasts had at least one detectable extracellular enzymatic activity. Cryptococcus antarcticus, D. aurantiaca, D. crocea, D. hungarica, Dioszegia sp., E. xenobiotica, Rh. glaciales, Rh. laryngis, Microglossum sp. 1 and Microglossum sp. 2 produced mycosporines. Of the yeast isolates, 41.7% produced pigments and/or mycosporines and could be considered adapted to survive in Antarctica. Most of the yeasts had extracellular enzymatic activities at 4ºC and 20ºC, indicating that they could be metabolically active in the sampled substrates.

  6. Warming and organic matter sources impact the proportion of dissolved to total activities in marine extracellular enzymatic rates

    KAUST Repository

    Baltar, Federico; Moran, Xose Anxelu G.; Lø nborg, Christian

    2017-01-01

    Extracellular enzymatic activities (EEAs) are the rate-limiting step in the degradation of organic matter. Extracellular enzymes can be found associated to cells or dissolved in the surrounding water. The proportion of cell-free EEA constitutes

  7. Effect of high hydrostatic pressure on the enzymatic hydrolysis of bovine serum albumin.

    Science.gov (United States)

    De Maria, Serena; Ferrari, Giovanna; Maresca, Paola

    2017-08-01

    The extent of enzymatic proteolysis mainly depends on accessibility of the peptide bonds, which stabilize the protein structure. The high hydrostatic pressure (HHP) process is able to induce, at certain operating conditions, protein displacement, thus suggesting that this technology can be used to modify protein resistance to the enzymatic attack. This work aims at investigating the mechanism of enzymatic hydrolysis assisted by HHP performed under different processing conditions (pressure level, treatment time). Bovine serum albumin was selected for the experiments, solubilized in sodium phosphate buffer (25 mg mL -1 , pH 7.5) with α-chymotrypsin or trypsin (E/S ratio = 1/10) and HPP treatment (100-500 MPa, 15-25 min). HHP treatment enhanced the extent of the hydrolysis reaction of globular proteins, being more effective than conventional hydrolysis. At HHP treatment conditions maximizing the protein unfolding, the hydrolysis degree of proteins was increased as a consequence of the increased exposure of peptide bonds to the attack of proteolytic enzymes. The maximum hydrolysis degree (10% and 7% respectively for the samples hydrolyzed with α-chymotrypsin and trypsin) was observed for the samples processed at 400 MPa for 25 min. At pressure levels higher than 400 MPa the formation of aggregates was likely to occur; thus the degree of hydrolysis decreased. Protein unfolding represents the key factor controlling the efficiency of HHP-assisted hydrolysis treatments. The peptide produced under high pressure showed lower dimensions and a different structure with respect to those of the hydrolysates obtained when the hydrolysis was carried out at atmospheric pressure, thus opening new frontiers of application in food science and nutrition. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  8. The effect of ultraviolet treatment on enzymatic activity and total phenolic content of minimally processed potato slices.

    Science.gov (United States)

    Teoh, Li Shing; Lasekan, Ola; Adzahan, Noranizan Mohd; Hashim, Norhashila

    2016-07-01

    In this work, potato slices were exposed to different doses of UV-C irradiation (i.e. 2.28, 6.84, 11.41, and 13.68 kJ m -2 ) with or without pretreatment [i.e. ascorbic acid and calcium chloride (AACCl) dip] and stored at 4 ± 1 °C. Changes in enzymatic activities of polyphenol oxidase (PPO), peroxidase (POD) and phenylalanine ammonia lyase (PAL), as well as total phenolic content (TPC) were investigated after 0, 3, 7 and 10 days of storage. Results showed that untreated and UV-C treated potato slices at 13.68 kJ m -2 dosage level showed significantly higher PPO, POD and PAL activities. Conversely, untreated potato slices showed the lowest TPC during storage period. Potato slices subjected to AACCl dip plus UV-C at 6.84 kJ m -2 produced lower PPO, POD and PAL activities, as well as maintained a high TPC during storage.

  9. The effects of different uranium concentrations on soil microbial populations and enzymatic activities

    International Nuclear Information System (INIS)

    Bagherifam, S.; Lakziyan, A.; Ahmadi, S. J.; Fotovvat, A.; Rahimi, M. F.

    2010-01-01

    Uranium is an ubiquitous constituent of natural environment with an average concentration of 4 mg/kg in earth crust. However, in local areas it may exceed the normal concentration due to human activities resulting in radionuclide contamination in groundwater and surface soil. The effect of six levels of uranium concentration (0, 50, 100,250. 500 and 1000 mg kg -1 ) on soil phosphatase activities and microbial populations were studied in a completely randomized design as a factorial experiment with three replications. The results showed a significant decrease in phosphatase activity. The result of the experiment suggests that soil microbial populations (bacteria, funji and actinomycetes) decrease by increasing the uranium levels in the soil. Therefore, assessment of soil enzymatic activities and microbial populations can be helpful as a useful index for a better management of uranium and radioactive contaminated soils.

  10. Enzymatic Activity Detection via Electrochemistry for Enceladus

    Science.gov (United States)

    Studemeister, Lucy; Koehne, Jessica; Quinn, Richard

    2017-01-01

    Electrochemical detection of biological molecules is a pertinent topic and application in many fields such as medicine, environmental spills, and life detection in space. Proteases, a class of molecules of interest in the search for life, catalyze the hydrolysis of peptides. Trypsin, a specific protease, was chosen to investigate an optimized enzyme detection system using electrochemistry. This study aims at providing the ideal functionalization of an electrode that can reliably detect a signal indicative of an enzymatic reaction from an Enceladus sample.

  11. Modulation of the pharmacological effects of enzymatically-active PLA2 by BTL-2, an isolectin isolated from the Bryothamnion triquetrum red alga

    Directory of Open Access Journals (Sweden)

    Nagano Celso S

    2008-06-01

    Full Text Available Abstract Background An interaction between lectins from marine algae and PLA2 from rattlesnake was suggested some years ago. We, herein, studied the effects elicited by a small isolectin (BTL-2, isolated from Bryothamnion triquetrum, on the pharmacological and biological activities of a PLA2 isolated from rattlesnake venom (Crotalus durissus cascavella, to better understand the enzymatic and pharmacological mechanisms of the PLA2 and its complex. Results This PLA2 consisted of 122 amino acids (approximate molecular mass of 14 kDa, its pI was estimated to be 8.3, and its amino acid sequence shared a high degree of similarity with that of other neurotoxic and enzymatically-active PLA2s. BTL-2 had a molecular mass estimated in approximately 9 kDa and was characterized as a basic protein. In addition, BTL-2 did not exhibit any enzymatic activity. The PLA2 and BTL-2 formed a stable heterodimer with a molecular mass of approximately 24–26 kDa, estimated by molecular exclusion HPLC. In the presence of BTL-2, we observed a significant increase in PLA2 activity, 23% higher than that of PLA2 alone. BTL-2 demonstrated an inhibition of 98% in the growth of the Gram-positive bacterial strain, Clavibacter michiganensis michiganensis (Cmm, but only 9.8% inhibition of the Gram-negative bacterial strain, Xanthomonas axonopodis pv passiflorae (Xap. PLA2 decreased bacterial growth by 27.3% and 98.5% for Xap and Cmm, respectively, while incubating these two proteins with PLA2-BTL-2 inhibited their growths by 36.2% for Xap and 98.5% for Cmm. PLA2 significantly induced platelet aggregation in washed platelets, whereas BTL-2 did not induce significant platelet aggregation in any assay. However, BTL-2 significantly inhibited platelet aggregation induced by PLA2. In addition, PLA2 exhibited strong oedematogenic activity, which was decreased in the presence of BTL-2. BTL-2 alone did not induce oedema and did not decrease or abolish the oedema induced by the 48

  12. Enzymatic production of N-acetyl-d-glucosamine from crayfish shell wastes pretreated via high pressure homogenization.

    Science.gov (United States)

    Wei, Guoguang; Zhang, Alei; Chen, Kequan; Ouyang, Pingkai

    2017-09-01

    This study presents an efficient pretreatment of crayfish shell using high pressure homogenization that enables N-acetyl-d-glucosamine (GlcNAc) production by chitinase. Firstly, the chitinase from Serratia proteamaculans NJ303 was screened for its ability to degrade crayfish shell and produce GlcNAc as the sole product. Secondly, high pressure homogenization, which caused the crayfish shell to adopt a fluffy netted structure that was characterized by Scanning electron microscope (SEM), Fourier transform infrared spectrometer (FT-IR), X-ray diffraction (XRD), was evaluated as the best pretreatment method. In addition, the optimal conditions of high pressure homogenization of crayfish shell were determined to be five cycles at a pressure of 400bar, which achieved a yield of 3.9g/L of GlcNAc from 25g/L of crayfish shell in a batch enzymatic reaction over 1.5h. The results showed high pressure homogenization might be an efficient method for direct utilization of crayfish shell for enzymatic production of GlcNAc. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Quantification of trypsin with a radioimmunoassay in herring larvae (Clupea harengus L.) compared with a highly sensitive fluorescence technique to determine tryptic enzyme activity

    International Nuclear Information System (INIS)

    Ueberschaer, B.; Pedersen, B.H.; Hjelmeland, K.

    1993-01-01

    Enzymatic activity and quantity of the protease trypsin were measured in individual herring larvae (Clupea harengus L.). The enzymatic activity assay was done by a fluorescence technique, and a radioimmunoassay was used for quantification of trypsin. The results are compared and the differences between the techniques discussed. Both methods have similar results, as high or low values in trypsin quantity were reflected in high or low values of tryptic activity. Quantity and activity were linearly and positively correlated, but small differences between methods were found at the lowest detection limits. Both techniques reflect the high variability between individual larvae. (orig.)

  14. Role of enzymatic and non enzymatic antioxidant in ameliorating salinity induced damage in nostoc muscorum

    International Nuclear Information System (INIS)

    Hend, A.; Abeer, A.; Allah, A.

    2015-01-01

    Presence of high salt concentration in the growth medium adversely affected the plant growth and productivity by altering its metabolic activities. Experiments were conducted on cyanobacteriaum Nostoc muscorum grown in nitrogen free medium supplemented with 250 mM NaCl to evaluate the salt stress induced changes in growth, antioxidants and lipid composition. Salt stress significantly reduced the growth and physio-biochemical attributes. Salt stress increased malonaldehyde content thereby causing alterations in the lipid fraction. Significant reduction in polyunsaturated fatty acids including phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylglycerol (PG), phosphatidylinositol (PI) and phosphatidylserine (PS) was observed. Where as diacylglycerol, sterol ester and non-esterified fatty acids were increased. Activities of antioxidant enzymes and contents of non-enzymatic antioxidants including glutathione enhanced due to salt stress. An increase in accumulation of proline was also observed. Hence increased activity of antioxidants and altered fatty acid composition was observed in salt stressed Nostoc muscorum. (author)

  15. High-throughput microplate technique for enzymatic hydrolysis of lignocellulosic biomass.

    Science.gov (United States)

    Chundawat, Shishir P S; Balan, Venkatesh; Dale, Bruce E

    2008-04-15

    Several factors will influence the viability of a biochemical platform for manufacturing lignocellulosic based fuels and chemicals, for example, genetically engineering energy crops, reducing pre-treatment severity, and minimizing enzyme loading. Past research on biomass conversion has focused largely on acid based pre-treatment technologies that fractionate lignin and hemicellulose from cellulose. However, for alkaline based (e.g., AFEX) and other lower severity pre-treatments it becomes critical to co-hydrolyze cellulose and hemicellulose using an optimized enzyme cocktail. Lignocellulosics are appropriate substrates to assess hydrolytic activity of enzyme mixtures compared to conventional unrealistic substrates (e.g., filter paper, chromogenic, and fluorigenic compounds) for studying synergistic hydrolysis. However, there are few, if any, high-throughput lignocellulosic digestibility analytical platforms for optimizing biomass conversion. The 96-well Biomass Conversion Research Lab (BCRL) microplate method is a high-throughput assay to study digestibility of lignocellulosic biomass as a function of biomass composition, pre-treatment severity, and enzyme composition. The most suitable method for delivering milled biomass to the microplate was through multi-pipetting slurry suspensions. A rapid bio-enzymatic, spectrophotometric assay was used to determine fermentable sugars. The entire procedure was automated using a robotic pipetting workstation. Several parameters that affect hydrolysis in the microplate were studied and optimized (i.e., particle size reduction, slurry solids concentration, glucan loading, mass transfer issues, and time period for hydrolysis). The microplate method was optimized for crystalline cellulose (Avicel) and ammonia fiber expansion (AFEX) pre-treated corn stover. Copyright 2008 Wiley Periodicals, Inc.

  16. Real-time ESI-MS of enzymatic conversion: impact of organic solvents and multiplexing.

    Science.gov (United States)

    Scheerle, Romy K; Grassmann, Johanna; Letzel, Thomas

    2012-01-01

    Different enzymatic assays were characterized systematically by real-time electrospray ionization mass spectrometry (ESI-MS) in the presence of organic solvents as well as in multiplex approaches and in a combination of both. Typically, biological enzymatic reactions are studied in aqueous solutions, since most enzymes show their full activity solely in aqueous solutions. However, in recent years, the use of organic solvents in combination with enzymatic reactions has gained increasing interest due to biotechnological advantages in chemical synthesis, development of online coupled setups screening for enzyme regulatory compounds, advantages regarding mass spectrometric detection and others. In the current study, the influence of several common organic solvents (methanol, ethanol, isopropanol, acetone, acetonitrile) on enzymatic activity (hen egg white lysozyme, chitinase, α-chymotrypsin, elastase from human neutrophils and porcine pancreas, acetylcholinesterase) was tested. Moreover, multiplexing is a promising approach enabling fast and cost-efficient screening methods, e.g. for determination of inhibitors in complex mixtures or in the field of biomedical research. Although in multiplexed setups the enzymatic activity may be affected by the presence of other substrates and/or enzymes, the expected advantages possibly will predominate. To investigate those effects, we measured multiple enzymatic assays simultaneously. For all conducted measurements, the conversion rate of the substrate(s) was calculated, which reflects the enzymatic activity. The results provide an overview about the susceptibility of the selected enzymes towards diverse factors and a reference point for many applications in analytical chemistry and biotechnology.

  17. Enzymatic determination of cadmium, zinc, and lead in plant materials

    International Nuclear Information System (INIS)

    Muginova, S.V.; Veselova, I.A.; Parova, L.M.; Shekhovtseva, T.N.

    2008-01-01

    Prospects are outlined for using the following enzymes (native and immobilized on polyurethane foam) in the rapid and highly sensitive determination of cadmium, zinc, and lead ions in plant materials (wild grass, fresh pea, and grape): horseradish peroxidase and alkaline phosphatases isolated from chicken intestine and Greenland seal small intestine. The analytical ranges of the above metals are 1x10 -3 -25; 7x10 -3 -250, and 3x10 -2 -67 mg/kg dry matter, respectively. The enzymatic determination procedures developed are based on the inhibiting effect of metal ions on the catalytic activity of peroxidase in the oxidation of o-dianisidine with hydrogen peroxide and alkaline phosphatases in the hydrolysis of p-nitrophenyl phosphate. The rates of enzymatic reactions were monitored spectrophotometrically or visually. In the analysis of plant extracts, their high acidity was diminished by choosing optimum dilution factors and pH values for test samples and the nature and concentration of a buffer solution. The interference of iron(III) was removed by introducing a 0.1 M tartaric acid solution into the indicator reaction. The accuracy of the results of the enzymatic determination of cadmium, zinc, and lead in plant materials was supported by atomic absorption spectrometry and anodic stripping voltammetry [ru

  18. The enzymatic hydrolysis of soy protein isolate by Corolase PP under high hydrostatic pressure and its effect on bioactivity and characteristics of hydrolysates.

    Science.gov (United States)

    Guan, Haining; Diao, Xiaoqin; Jiang, Fan; Han, Jianchun; Kong, Baohua

    2018-04-15

    Enzymatic hydrolysis of soy protein isolate by Corolase PP under high hydrostatic pressure conditions was studied and the effects of hydrolysis on antioxidant and antihypertensive activities were investigated. As observed, high hydrostatic pressure (80-300MPa) enhanced the hydrolytic efficiency of Corolase PP and decreased the surface hydrophobicity of the hydrolysates. Hydrolysates obtained at 200MPa for 4h had higher bioactivities (reducing power, ABTS radical-scavenging and ACE inhibitory activities). The molecular weight (MW) determination indicated that hydrolysis at high hydrostatic pressure could increase the production of small peptides (hydrostatic pressure combined with Corolase PP treatments could be used as a potential technology to produce bioactive peptides from soy protein isolate. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Biocolloids with ordered urease multilayer shells as enzymatic reactors.

    Science.gov (United States)

    Lvov, Y; Caruso, F

    2001-09-01

    The preparation of biocolloids with organized enzyme-containing multilayer shells for exploitation as colloidal enzymatic nanoreactors is described. Urease multilayers were assembled onto submicrometer-sized polystyrene spheres by the sequential adsorption of urease and polyelectrolyte, in a predetermined order, utilizing electrostatic interactions for layer growth. The catalytic activity of the biocolloids increased proportionally with the number of urease layers deposited on the particles, demonstrating that biocolloid particles with tailored enzymatic activities can be produced. It was further found that precoating the latex spheres with nanoparticles (40-nm silica or 12-nm magnetite) enhanced both the stability (with respect to adsorption) and enzymatic activity of the urease multilayers. The presence of the magnetite nanoparticle coating also provided a magnetic function that allowed the biocolloids to be easily and rapidly separated with a permanent magnet. The fabrication of such colloids opens new avenues for the application of bioparticles and represents a promising route for the creation of complex catalytic particles.

  20. The effect of chlorsulfurone and MCPB-Na on the enzymatic activity of microorganisms

    Directory of Open Access Journals (Sweden)

    Filimon Marioara Nicoleta

    2014-01-01

    Full Text Available herbicides, have a broad spectrum effect on weeds, in relatively low doses and with a much reduced toxicity on livestock. In this study were used two herbicides: dacsulfuron with the active substance chlorsulfuron (0.005 - 0.035 μg/g soil and butoxone with the active substance MCPB-Na (0.005 - 0.035 mg/L/g soil. The samples were collected from a depth of 0-20 cm from chernozem soil. The effect of herbicide was estimated by measuring the activity of catalase, actual and potential dehydrogenase, urease and cellulase activities. All samples being incubated for 10 days at 27°C using Sapp medium for isolation and study of cellulosolytic bacteria. The inhibitory effect of the tested herbicides was the most intense for the urease and dehydrogenase enzymatic activities. The most resistant cellulosolytic bacteria to the effects of dacsulfuron were Cellfalcicula fusca, Cellfalcicula viridis, Cellvibrio fulvus and Fuseaux veris and for butoxone Cellfalcicula mucosa, C. viridis and C. fulvus.

  1. Optimization of the Enzymatic Saccharification Process of Milled Orange Wastes

    Directory of Open Access Journals (Sweden)

    Daniel Velasco

    2017-08-01

    Full Text Available Orange juice production generates a very high quantity of residues (Orange Peel Waste or OPW-50–60% of total weight that can be used for cattle feed as well as feedstock for the extraction or production of essential oils, pectin and nutraceutics and several monosaccharides by saccharification, inversion and enzyme-aided extraction. As in all solid wastes, simple pretreatments can enhance these processes. In this study, hydrothermal pretreatments and knife milling have been analyzed with enzyme saccharification at different dry solid contents as the selection test: simple knife milling seemed more appropriate, as no added pretreatment resulted in better final glucose yields. A Taguchi optimization study on dry solid to liquid content and the composition of the enzymatic cocktail was undertaken. The amounts of enzymatic preparations were set to reduce their impact on the economy of the process; however, as expected, the highest amounts resulted in the best yields to glucose and other monomers. Interestingly, the highest content in solid to liquid (11.5% on dry basis rendered the best yields. Additionally, in search for process economy with high yields, operational conditions were set: medium amounts of hemicellulases, polygalacturonases and β-glucosidases. Finally, a fractal kinetic modelling of results for all products from the saccharification process indicated very high activities resulting in the liberation of glucose, fructose and xylose, and very low activities to arabinose and galactose. High activity on pectin was also observed, but, for all monomers liberated initially at a fast rate, high hindrances appeared during the saccharification process.

  2. A rigidifying salt-bridge favors the activity of thermophilic enzyme at high temperatures at the expense of low-temperature activity.

    Science.gov (United States)

    Lam, Sonia Y; Yeung, Rachel C Y; Yu, Tsz-Ha; Sze, Kong-Hung; Wong, Kam-Bo

    2011-03-01

    Thermophilic enzymes are often less active than their mesophilic homologues at low temperatures. One hypothesis to explain this observation is that the extra stabilizing interactions increase the rigidity of thermophilic enzymes and hence reduce their activity. Here we employed a thermophilic acylphosphatase from Pyrococcus horikoshii and its homologous mesophilic acylphosphatase from human as a model to study how local rigidity of an active-site residue affects the enzymatic activity. Acylphosphatases have a unique structural feature that its conserved active-site arginine residue forms a salt-bridge with the C-terminal carboxyl group only in thermophilic acylphosphatases, but not in mesophilic acylphosphatases. We perturbed the local rigidity of this active-site residue by removing the salt-bridge in the thermophilic acylphosphatase and by introducing the salt-bridge in the mesophilic homologue. The mutagenesis design was confirmed by x-ray crystallography. Removing the salt-bridge in the thermophilic enzyme lowered the activation energy that decreased the activation enthalpy and entropy. Conversely, the introduction of the salt-bridge to the mesophilic homologue increased the activation energy and resulted in increases in both activation enthalpy and entropy. Revealed by molecular dynamics simulations, the unrestrained arginine residue can populate more rotamer conformations, and the loss of this conformational freedom upon the formation of transition state justified the observed reduction in activation entropy. Our results support the conclusion that restricting the active-site flexibility entropically favors the enzymatic activity at high temperatures. However, the accompanying enthalpy-entropy compensation leads to a stronger temperature-dependency of the enzymatic activity, which explains the less active nature of the thermophilic enzymes at low temperatures.

  3. A rigidifying salt-bridge favors the activity of thermophilic enzyme at high temperatures at the expense of low-temperature activity.

    Directory of Open Access Journals (Sweden)

    Sonia Y Lam

    2011-03-01

    Full Text Available Thermophilic enzymes are often less active than their mesophilic homologues at low temperatures. One hypothesis to explain this observation is that the extra stabilizing interactions increase the rigidity of thermophilic enzymes and hence reduce their activity. Here we employed a thermophilic acylphosphatase from Pyrococcus horikoshii and its homologous mesophilic acylphosphatase from human as a model to study how local rigidity of an active-site residue affects the enzymatic activity.Acylphosphatases have a unique structural feature that its conserved active-site arginine residue forms a salt-bridge with the C-terminal carboxyl group only in thermophilic acylphosphatases, but not in mesophilic acylphosphatases. We perturbed the local rigidity of this active-site residue by removing the salt-bridge in the thermophilic acylphosphatase and by introducing the salt-bridge in the mesophilic homologue. The mutagenesis design was confirmed by x-ray crystallography. Removing the salt-bridge in the thermophilic enzyme lowered the activation energy that decreased the activation enthalpy and entropy. Conversely, the introduction of the salt-bridge to the mesophilic homologue increased the activation energy and resulted in increases in both activation enthalpy and entropy. Revealed by molecular dynamics simulations, the unrestrained arginine residue can populate more rotamer conformations, and the loss of this conformational freedom upon the formation of transition state justified the observed reduction in activation entropy.Our results support the conclusion that restricting the active-site flexibility entropically favors the enzymatic activity at high temperatures. However, the accompanying enthalpy-entropy compensation leads to a stronger temperature-dependency of the enzymatic activity, which explains the less active nature of the thermophilic enzymes at low temperatures.

  4. Self-Assembly of Spider Silk-Fusion Proteins Comprising Enzymatic and Fluorescence Activity.

    Science.gov (United States)

    Humenik, Martin; Mohrand, Madeleine; Scheibel, Thomas

    2018-04-18

    The recombinant spider silk protein eADF4(C16) was genetically fused either with esterase 2 (EST2) or green fluorescent protein (GFP). The fusions EST-eADF4(C16) and GFP-eADF4(C16) were spectroscopically investigated and showed native structures of EST and GFP. The structural integrity was confirmed by the enzymatic activity of EST and the fluorescence of GFP. The spider silk moiety retained its intrinsically unstructured conformation in solution and the self-assembly into either nanofibrils or nanoparticles could be controlled by the concentration of phosphate. Particles, however, showed significantly lower activity of the EST and GFP domains likely caused by a steric hindrance. However, upon self-assembly of EST-eADF4(C16) and GFP-eADF4(C16) into fibrils the protein activities were retained. In general, the fusion of globular enzymes with the spider silk domain allows the generation of fibrous biomaterials with catalytic or light emitting properties.

  5. Vancomycin analogues containing monosaccharides exhibit improved antibiotic activity: a combined one-pot enzymatic glycosylation and chemical diversification strategy.

    Science.gov (United States)

    Thayer, Desiree A; Wong, Chi-Huey

    2006-09-18

    Many natural products contain carbohydrate moieties that contribute to their biological activity. Manipulation of the carbohydrate domain of natural products through multiple glycosylations to identify new derivatives with novel biological activities has been a difficult and impractical process. We report a practical one-pot enzymatic approach with regeneration of cosubstrates to synthesize analogues of vancomycin that contain an N-alkyl glucosamine, which exhibited marked improvement in antibiotic activity against a vancomycin-resistant strain of Enterococcus.

  6. Multi-Scale Computational Enzymology: Enhancing Our Understanding of Enzymatic Catalysis

    Science.gov (United States)

    Gherib, Rami; Dokainish, Hisham M.; Gauld, James W.

    2014-01-01

    Elucidating the origin of enzymatic catalysis stands as one the great challenges of contemporary biochemistry and biophysics. The recent emergence of computational enzymology has enhanced our atomistic-level description of biocatalysis as well the kinetic and thermodynamic properties of their mechanisms. There exists a diversity of computational methods allowing the investigation of specific enzymatic properties. Small or large density functional theory models allow the comparison of a plethora of mechanistic reactive species and divergent catalytic pathways. Molecular docking can model different substrate conformations embedded within enzyme active sites and determine those with optimal binding affinities. Molecular dynamics simulations provide insights into the dynamics and roles of active site components as well as the interactions between substrate and enzymes. Hybrid quantum mechanical/molecular mechanical (QM/MM) can model reactions in active sites while considering steric and electrostatic contributions provided by the surrounding environment. Using previous studies done within our group, on OvoA, EgtB, ThrRS, LuxS and MsrA enzymatic systems, we will review how these methods can be used either independently or cooperatively to get insights into enzymatic catalysis. PMID:24384841

  7. Multi-Scale Computational Enzymology: Enhancing Our Understanding of Enzymatic Catalysis

    Directory of Open Access Journals (Sweden)

    Rami Gherib

    2013-12-01

    Full Text Available Elucidating the origin of enzymatic catalysis stands as one the great challenges of contemporary biochemistry and biophysics. The recent emergence of computational enzymology has enhanced our atomistic-level description of biocatalysis as well the kinetic and thermodynamic properties of their mechanisms. There exists a diversity of computational methods allowing the investigation of specific enzymatic properties. Small or large density functional theory models allow the comparison of a plethora of mechanistic reactive species and divergent catalytic pathways. Molecular docking can model different substrate conformations embedded within enzyme active sites and determine those with optimal binding affinities. Molecular dynamics simulations provide insights into the dynamics and roles of active site components as well as the interactions between substrate and enzymes. Hybrid quantum mechanical/molecular mechanical (QM/MM can model reactions in active sites while considering steric and electrostatic contributions provided by the surrounding environment. Using previous studies done within our group, on OvoA, EgtB, ThrRS, LuxS and MsrA enzymatic systems, we will review how these methods can be used either independently or cooperatively to get insights into enzymatic catalysis.

  8. ENZYMATIC AND NON-ENZYMATIC ANTIOXIDANT DEFENSE WITH ALZHEIMER DISEASE1

    Directory of Open Access Journals (Sweden)

    A. Vaisi-Raygani

    2007-07-01

    Full Text Available The etiopathogenesis of Alzheimer's disease (AD is still unclear.  However, long-term oxidative stress is believed to be one of the major contributing factors in progression of neuronal degeneration and decline of cognitive function in AD. In order to assess the presence of oxidative stress in AD, we examined the enzymatic activities of the erythrocyte Cu-Zn superoxide dismutase (Cu-Zn SOD, glutathione peroxidase (GSH-Px, catalase (CAT, and plasma level of total antioxidant status (TAS in AD and control groups (age and sex-matched. The results showed that the Cu-Zn SOD activity was significantly higher and the level of GSH-Px and TAS activities were significantly lower in AD subjects than that in the control group (2111 ± 324 U/grHb, 43.7 ± 11.6 U/grHb, and 1.17 ± 0.23 mmol/l compared with 1371 ± 211 U/grHb; t= -2.17, P = 0.036, 56.3 ± 9.5 U/grHb; t=3.8, P = 0.014, and 1.54±0.2 mmol/l; t=11.18, P < 0.001, respectively.  While, the erythrocyte CAT activity was lower in AD subjects compared to the control group, the difference was not statistically significant (t = 1.3, P = 0.15. These findings support the idea that the oxidative stress plays an important role in the pathogenesis underlying AD neurodegeneration. In addition, the enzymatic activity of the erythrocyte Cu-Zn SOD and GSH-Px and the plasma level of TAS can be used as a measure of the oxidative stress and a marker for pathological changes in the brain of patients with AD. 

  9. Identification of Key Residues for Enzymatic Carboxylate Reduction

    Directory of Open Access Journals (Sweden)

    Holly Stolterfoht

    2018-02-01

    Full Text Available Carboxylate reductases (CARs, E.C. 1.2.1.30 generate aldehydes from their corresponding carboxylic acid with high selectivity. Little is known about the structure of CARs and their catalytically important amino acid residues. The identification of key residues for carboxylate reduction provides a starting point to gain deeper understanding of enzymatic carboxylate reduction. A multiple sequence alignment of CARs with confirmed activity recently identified in our lab and from the literature revealed a fingerprint of conserved amino acids. We studied the function of conserved residues by multiple sequence alignments and mutational replacements of these residues. In this study, single-site alanine variants of Neurospora crassa CAR were investigated to determine the contribution of conserved residues to the function, expressability or stability of the enzyme. The effect of amino acid replacements was investigated by analyzing enzymatic activity of the variants in vivo and in vitro. Supported by molecular modeling, we interpreted that five of these residues are essential for catalytic activity, or substrate and co-substrate binding. We identified amino acid residues having significant impact on CAR activity. Replacement of His 237, Glu 433, Ser 595, Tyr 844, and Lys 848 by Ala abolish CAR activity, indicating their key role in acid reduction. These results may assist in the functional annotation of CAR coding genes in genomic databases. While some other conserved residues decreased activity or had no significant impact, four residues increased the specific activity of NcCAR variants when replaced by alanine. Finally, we showed that NcCAR wild-type and mutants efficiently reduce aliphatic acids.

  10. Enzymatic determination of rare earth elements by use of pyrophosphotases

    International Nuclear Information System (INIS)

    Shekhovtseva, T.N.; Pirogova, S.V.; Fedorova, O.M.; Dolmanova, I.F.; Bajkov, A.A.

    1993-01-01

    A highly sensitive (determination limit 8 x 10 -6 - 4 x 10 -4 μg/ml) and selective enzymatic method for determination of rare earth elements has been developed. The method is based on inhibition action of rare earths on the catalytic activity of pyrophosphates isolated from bakery geast and E. Coli. The mechanism of the rare earth element action, corresponding to competitive inhibition, has been established

  11. Enzymatic synthesis of vanillin

    NARCIS (Netherlands)

    van den Heuvel, RHH; Fraaije, MW; Laane, C; van Berkel, WJH; Heuvel, Robert H.H. van den; Berkel, Willem J.H. van

    Due to increasing interest in natural vanillin, two enzymatic routes for the synthesis of vanillin were developed. The flavoprotein vanillyl alcohol oxidase (VAO) acts on a wide range of phenolic compounds and converts both creosol and vanillylamine to vanillin with high yield. The VAO-mediated

  12. Enzymatic synthesis of vanillin

    NARCIS (Netherlands)

    Heuvel, van den R.H.H.; Fraaije, M.W.; Laane, C.; Berkel, van W.J.H.

    2001-01-01

    Due to increasing interest in natural vanillin, two enzymatic routes for the synthesis of vanillin were developed. The flavoprotein vanillyl alcohol oxidase (VAO) acts on a wide range of phenolic compounds and converts both creosol and vanillylamine to vanillin with high yield. The VAO-mediated

  13. ASSOCIATION BETWEEN ENZYMATIC AND NON-ENZYMATIC ANTIOXIDANT DEFENSE WITH ALZHEIMER DISEASE

    Directory of Open Access Journals (Sweden)

    A. Vaisi-Raygani

    2008-04-01

    Full Text Available The etiopathogenesis of dementia in Alzheimer's disease (AD is still unclear. However, long-term oxidative stress is believed to be one of the major contributing factors in progression of neuronal degeneration and decline of cognitive function in AD. In order to assess the presence of oxidative stress in AD, we examined the enzymatic activities of the erythrocyte Cu-Zn superoxide dismutase (Cu-Zn SOD, glutathione peroxidase (GSH-Px, catalase (CAT, and plasma level of total antioxidant status (TAS in AD and control groups (age and sex-matched. The results showed that the Cu-Zn SOD activity was significantly higher and the level of GSH-Px and TAS activities were significantly lower in AD subjects than that in the control group (2111±324 U/grHb, 43.7±11.6 U/grHb, and 1.17 ±0.23 mmol/L compared with 1371±211 U/gHb; t= -2.17, p=0.036, 56.3±9.5 U/gHb; t=3.8, p=0.014, and 1.54±0.2 mmol/L; t=11.18, P<0.001, respectively. While, the erythrocyte CAT activity was lower in AD subjects compared to the control group, the difference was not statistically significant (t=1.3, P=0.15. These findings support the idea that the oxidative stress plays an important role in the pathogenesis underlying AD neurodegeneration. In addition, the enzymatic activity of the erythrocyte Cu-Zn SOD and GSH-Px and the plasma level of TAS can be used as a measure of the oxidative stress and a marker for pathological changes in the brain of patients with AD.

  14. Enzymatic transesterification of used frying oils

    Energy Technology Data Exchange (ETDEWEB)

    Kovacs, S.; Hancsok, J. (Univ. of Pannonia, Veszprem (HU)), Email: hancsokj@almos.uni-pannon.hu

    2009-07-01

    The research of converting used frying oils to less harmful products with much higher value was forced by environmental, human biological and economical reasons. One possible pathway of the transformation is the enzymatic transesterification. Through the research work used frying oils (UFO) and sunflower oils (SO) from different origins were first properly pre-treated. Then the previously mentioned feeds and different mixtures of them were transesterified in the presence of Novozym 435 enzyme catalyst under different process conditions. Characteristics of the produced methyl esters were evaluated according to the requirements of EN 14214:2009 standard. We determined that the transesterification of used frying oils is not expediential in the presence of enzyme catalyst because the significant decreasing of catalyst activity. We have found proper UFO and SO mixtures and combination of process conditions (pressure: atmospheric, temperature: 54 +-1 deg C; methanol to triglyceride molar ratio: 4:1; reaction time: 16 hours) resulting in high (>90 %) yield of monoesters. We clearly established that the best results through the enzymatic transesterification were obtained with the improved sunflower oils containing the highest amount (>88 %) of oleic acid and the used frying oils originated from this source. (orig.)

  15. Enzymatic Modification of Sphingomyelin

    DEFF Research Database (Denmark)

    Due to its major role in maintaining the water-retaining properties of the epidermis, ceramide is of great commercial potential in cosmetic and pharmaceuticals such as hair and skin care products. Currently, chemical synthesis of ceramide is a costly process, and developments of alternative cost......-efficient, high yield production methods are of great interest. In the present study, the potential of producing ceramide through the enzymatic hydrolysis of sphingomyelin have been studied. sphingomyelin is a ubiquitous membrane-lipid and rich in dairy products or by-products. It has been verified...... that sphingomyelin modification gives a feasible approach to the potential production of ceramide. The reaction system has been improved through system evaluation and the optimization of several important factors, and phospholipase C from Clostridium perfringens shows higher activity towards the hydrolysis reaction...

  16. Unraveling the mechanism responsible for the contrasting tolerance of Synechocystis and Synechococcus to Cr(VI): Enzymatic and non-enzymatic antioxidants

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Alka [Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Ballal, Anand, E-mail: aballal@barc.gov.in [Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 40085 (India)

    2015-07-15

    Highlights: • Cr(VI) accumulation generates higher ROS in Synechocystis than in Synechococcus. • Synechococcus exhibits better photosynthetic activity in response to Cr(VI). • Synechococcus has higher enzymatic/non-enzymatic antioxidants than Synechocystis. • Synechococcus shows better tolerance to other oxidative stresses than Synechocystis. • Differential detoxification of ROS is responsible for the contrasting tolerance to Cr(VI) - Abstract: Two unicellular cyanobacteria, Synechocystis and Synechococcus, showed contrasting tolerance to Cr(VI); with Synechococcus being 12-fold more tolerant than Synechocystis to potassium dichromate. The mechanism responsible for this differential sensitivity to Cr(VI) was explored in this study. Total content of photosynthetic pigments as well as photosynthetic activity decreased at lower concentration of Cr(VI) in Synechocystis as compared to Synechococcus. Experiments with {sup 51}Cr showed Cr to accumulate intracellularly in both the cyanobacteria. At lower concentrations, Cr(VI) caused excessive ROS generation in Synechocystis as compared to that observed in Synechococcus. Intrinsic levels of enzymatic antioxidants, i.e., superoxide dismutase, catalase and 2-Cys-peroxiredoxin were considerably higher in Synechococcus than Synechocystis. Content of total thiols (both protein as well as non-protein) and reduced glutathione (GSH) was also higher in Synechococcus as compared to Synechocystis. This correlated well with higher content of carbonylated proteins observed in Synechocystis than Synechococcus. Additionally, in contrast to Synechocystis, Synechococcus exhibited better tolerance to other oxidative stresses like high intensity light and H{sub 2}O{sub 2}. The data indicate that the disparity in the ability to detoxify ROS could be the primary mechanism responsible for the differential tolerance of these cyanobacteria to Cr(VI)

  17. The development of orally administrable gemcitabine prodrugs with D-enantiomer amino acids: enhanced membrane permeability and enzymatic stability.

    Science.gov (United States)

    Tsume, Yasuhiro; Incecayir, Tuba; Song, Xueqin; Hilfinger, John M; Amidon, Gordon L

    2014-04-01

    Gemcitabine prodrugs with D- and L-configuration amino acids were synthesized and their chemical stability in buffers, resistance to glycosidic bond metabolism, enzymatic activation, permeability in Caco-2 cells and mouse intestinal membrane, anti-proliferation activity in cancer cell were determined and compared to that of parent drug, gemcitabine. Prodrugs containing D-configuration amino acids were enzymatically more stable than ones with L-configuration amino acids. The activation of all gemcitabine prodrugs was 1.3-17.6-fold faster in cancer cell homogenate than their hydrolysis in buffer, suggesting enzymatic action. The enzymatic activation of amino acid monoester prodrugs containing D-configuration amino acids in cell homogenates was 2.2-10.9-fold slower than one of amino acid monoester prodrugs with L-configuration amino acids. All prodrugs exhibited enhanced resistance to glycosidic bond metabolism by thymidine phosphorylase compared to parent gemcitabine. Gemcitabine prodrugs showed superior the effective permeability in mouse jejunum to gemcitabine. More importantly, the high plasma concentration of d-amino acid gemcitabine prodrugs was observed more than one of L-amino acid gemcitabine prodrugs. In general, the 5'-mono-amino acid monoester gemcitabine prodrugs exhibited higher permeability and uptake than their parent drug, gemcitabine. Cell proliferation assays in AsPC-1 pancreatic ductal cell line indicated that gemcitabine prodrugs were more potent than their parent drug, gemcitabine. The transport and enzymatic profiles of 5'-D-valyl-gemcitabine and 5'-D-phenylalanyl-gemcitabine suggest their potential for increased oral uptake and delayed enzymatic bioconversion as well as enhanced uptake and cytotoxic activity in cancer cells, would facilitate the development of oral dosage form for anti-cancer agents and, hence, improve the quality of life for the cancer patients. Copyright © 2014. Published by Elsevier B.V.

  18. Enzymatic hydrolysis of plant extracts containing inulin

    Energy Technology Data Exchange (ETDEWEB)

    Guiraud, J.P.; Galzy, P.

    1981-10-01

    Inulin-rich extracts of chicory and Jerusalem artichoke are a good potential source of fructose. Total enzymatic hydrolysis of these extracts can be effected by yeast inulinases (EC 3.2.1.7). Chemical prehydrolysis is unfavourable. Enzymatic hydrolysis has advantages over chemical hydrolysis: it does not produce a dark-coloured fraction or secondary substances. It is possible to envisage the preparation of high fructose syrups using this process. (Refs. 42).

  19. Chromophoric dissolved organic matter and microbial enzymatic activity. A biophysical approach to understand the marine carbon cycle.

    Science.gov (United States)

    Gonnelli, Margherita; Vestri, Stefano; Santinelli, Chiara

    2013-12-01

    This study reports the first information on extracellular enzymatic activity (EEA) combined with a study of DOM dynamics at the Arno River mouth. DOM dynamics was investigated from both a quantitative (dissolved organic carbon, DOC) and a qualitative (absorption and fluorescence of chromophoric DOM, CDOM) perspective. The data here reported highlight that the Arno River was an important source of both DOC and CDOM for this coastal area. CDOM optical properties suggested that terrestrial DOM did not undergo simple dilution at the river mouth but, other physical-chemical and biological processes were probably at work to change its molecular characteristics. This observation was further supported by the "potential" enzymatic activity of β-glucosidase (BG) and leucine aminopeptidase (LAP). Their Vmax values were markedly higher in the river water than in the seawater and their ratio suggested that most of the DOM used by microbes in the Arno River was polysaccharide-like, while in the seawater it was mainly protein-like. © 2013. Published by Elsevier B.V. All rights reserved.

  20. Electrodeposition of flower-like platinum on electrophoretically grown nitrogen-doped graphene as a highly sensitive electrochemical non-enzymatic biosensor for hydrogen peroxide detection

    International Nuclear Information System (INIS)

    Tajabadi, M.T.; Sookhakian, M.; Zalnezhad, E.; Yoon, G.H.; Hamouda, A.M.S.; Azarang, Majid; Basirun, W.J.; Alias, Y.

    2016-01-01

    Highlights: • Nitrogen doped graphene with different thickness by electrophoretic deposition. • The conductivity of N-graphene layer depends on the tickness. • Support of platinum shows efficient electrocatalytic performance for biosensor. • CV curves and amperometric responses improved and optimized in the presence of N-graphene. - Abstract: An efficient non-enzymatic biosensor electrode consisting of nitrogen-doped graphene (N-graphene) and platinum nanoflower (Pt NF) with different N-graphene loadings were fabricated on indium tin oxide (ITO) glass using a simple layer-by-layer electrophoretic and electrochemical sequential deposition approach. N-graphene was synthesized by annealing graphene oxide with urea at 900 °C. The structure and morphology of the as-fabricated non-enzymatic biosensor electrodes were determined using X-ray diffraction, field emission electron microscopy, transmission electron microscopy, Raman and X-ray photoelectron spectra. The as-fabricated Pt NF-N-graphene-modified ITO electrodes with different N-graphene loadings were utilized as a non-enzymatic biosensor electrode for the detection of hydrogen peroxide (H_2O_2). The behaviors of the hybrid electrodes towards H_2O_2 reduction were assessed using chronoamperometry, cyclic voltammetry and electrochemical impedance spectroscopy analysis. The Pt NF-N-graphene-modified ITO electrode with a 0.05 mg ml"−"1 N-graphene loading exhibited the lowest detection limit, fastest amperometric sensing, a wide linear response range, excellent stability and reproducibility for the non-enzymatic H_2O_2 detection, due to the synergistic effect between the electrocatalytic activity of the Pt NF and the high conductivity and large surface area of N-graphene.

  1. Urease immobilized polymer hydrogel: Long-term stability and enhancement of enzymatic activity.

    Science.gov (United States)

    Kutcherlapati, S N Raju; Yeole, Niranjan; Jana, Tushar

    2016-02-01

    A method has been developed in which an enzyme namely urease was immobilized inside hydrogel matrix to study the stability and enzymatic activity in room temperature (∼27-30°C). This urease coupled hydrogel (UCG) was obtained by amine-acid coupling reaction and this procedure is such that it ensured the wider opening of mobile flap of enzyme active site. A systematic comparison of urea-urease assay and the detailed kinetic data clearly revealed that the urease shows activity for more than a month when stored at ∼27-30°C in case of UCG whereas it becomes inactive in case of free urease (enzyme in buffer solution). The aqueous microenvironment inside the hydrogel, unusual morphological features and thermal behaviour were believed to be the reasons for unexpected behaviour. UCG displayed enzyme activity at basic pH and up to 60°C. UCG showed significant enhancement in activity against thermal degradation compared to free urease. In summary, this method is a suitable process to stabilize the biomacromolecules in standard room temperature for many practical uses. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Enzymatic activity of anthropogenic proto-organic soils in soilless farming

    Science.gov (United States)

    Bireescu, Geanina; Dazzi, Carmelo; Laudicina, Vito Armando; Lo Papa, Giuseppe

    2017-04-01

    In soilless agriculture and horticulture coir is the more used substratum to grow plants because it is widely available and more environmentally friendly than sphagnum or peat. In Italy, soilless agriculture concerns an area of about 1,000 hectares, particularly concentrated in Sicily. The southern coastal belt of this region is the area interested by the most significant experiences in the application of techniques of soilless cultivation that, recently, has been used also for growing table grapes. Starting from the above consideration we suppose that the features of the coconut fiber underlay an evident transformation and that even after few years of table grape cultivation, such organic material undergone to a transformation that allows for the formation of a proto-organic soil (a proto-Histosol, we supposed). If this is true, we believe that, in this case, to speak about soilless cultivation is for sure misleading for the common people, as we should define this cultivation "on anthropogenic soils" instead. To fit the aims of this survey we used a big greenhouse devoted to soilless cultivation of table grape in a farm in the Southern Sicily We have considered the enzymatic activity that characterized the coconut fiber after 3 cycles of cultivation of table grapes. We used as a control the coconut fiber that the farmer used to prepare pots for soilless cultivation and coconut fiber of: 6 pots at the end of the first productive cycle 6 pots at the end of the second cycle and 3 pots at the end of the third cycle. On these organic samples we investigated three enzymes, belonging to oxydoreductase (catalase and dehydrogenase) and hydrolase (urease) classes. Statistical analysis of the investigated enzymes was developed using IBM Statistic SPSS v20 by ANOVA, Tukey test HSD for p ≤ 0.01 and Multivariate Statistical Analysis. Results have shown significant differences in enzymes content and quality among coir tests. The use of the coco fiber, as nutritive substratum

  3. D-Amino acid oxidase bio-functionalized platforms: Toward an enhanced enzymatic bio-activity

    Science.gov (United States)

    Herrera, Elisa; Valdez Taubas, Javier; Giacomelli, Carla E.

    2015-11-01

    The purpose of this work is to study the adsorption process and surface bio-activity of His-tagged D-amino acid oxidase (DAAO) from Rhodotorula gracilis (His6-RgDAAO) as the first step for the development of an electrochemical bio-functionalized platform. With such a purpose this work comprises: (a) the His6-RgDAAO bio-activity in solution determined by amperometry, (b) the adsorption mechanism of His6-RgDAAO on bare gold and carboxylated modified substrates in the absence (substrate/COO-) and presence of Ni(II) (substrate/COO- + Ni(II)) determined by reflectometry, and (c) the bio-activity of the His6-RgDAAO bio-functionalized platforms determined by amperometry. Comparing the adsorption behavior and bio-activity of His6-RgDAAO on these different solid substrates allows understanding the contribution of the diverse interactions responsible for the platform performance. His6-RgDAAO enzymatic performance in solution is highly improved when compared to the previously used pig kidney (pk) DAAO. His6-RgDAAO exhibits an amperometrically detectable bio-activity at concentrations as low as those expected on a bio-functional platform; hence, it is a viable bio-recognition element of D-amino acids to be coupled to electrochemical platforms. Moreover, His6-RgDAAO bio-functionalized platforms exhibit a higher surface activity than pkDAAO physically adsorbed on gold. The platform built on Ni(II) modified substrates present enhanced bio-activity because the surface complexes histidine-Ni(II) provide with site-oriented, native-like enzymes. The adsorption mechanism responsible of the excellent performance of the bio-functionalized platform takes place in two steps involving electrostatic and bio-affinity interactions whose prevalence depends on the degree of surface coverage.

  4. Enzymatic protein hydrolysates from high pressure-pretreated isolated pea proteins have better antioxidant properties than similar hydrolysates produced from heat pretreatment.

    Science.gov (United States)

    Girgih, Abraham T; Chao, Dongfang; Lin, Lin; He, Rong; Jung, Stephanie; Aluko, Rotimi E

    2015-12-01

    Isolated pea protein (IPP) dispersions (1%, w/v) were pretreated with high pressure (HP) of 200, 400, or 600 MPa for 5 min at 24 °C or high temperature (HT) for 30 min at 100 °C prior to hydrolysis with 1% (w/w) Alcalase. HP pretreatment of IPP at 400 and 600 MPa levels led to significantly (P40%) oxygen radical absorption capacity (ORAC) of hydrolysates. 2,2-Diphenyl-1-picrylhydrazyl, superoxide radical and hydroxyl radical scavenging activities of pea protein hydrolysates were also significantly (PProtein hydrolysates from HT IPP showed no ORAC, superoxide or hydroxyl scavenging activity but had significantly (Pprotein hydrolysates had weaker antioxidant properties than glutathione but overall, the HP pretreatment was superior to HT pretreatment in facilitating enzymatic release of antioxidant peptides from IPP. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. The enzymatic activity of 5-aminoimidazole-4-carboxamide ribonucleotide formyltransferase/IMP cyclohydrolase (ATIC) is enhanced by NPM-ALK

    DEFF Research Database (Denmark)

    Boccalatte, Francesco E; Voena, Claudia; Riganti, Chiara

    2009-01-01

    . A well-defined set of ALK-associated tyrosine phospho-peptides, including metabolic enzymes, kinases, ribosomal and cytoskeletal proteins was identified. Validation studies confirmed that VASP and ATIC associated with NPM-ALK and their phosphorylation required ALK activity. ATIC phosphorylation was also...... documented in cell lines and primary tumors carrying ALK proteins and other tyrosine kinases, including TPR-Met and wild type c-Met. Functional analyses revealed that ALK-mediated ATIC phosphorylation enhanced its enzymatic activity, dampering the methotrexate-mediated transformylase activity inhibition...

  6. Standardization and quality control in quantifying non-enzymatic oxidative protein modifications in relation to ageing and disease: Why is it important and why is it hard?

    DEFF Research Database (Denmark)

    Nedić, Olgica; Rogowska-Wrzesinska, Adelina; Rattan, Suresh

    2015-01-01

    Post-translational modifications (PTM) of proteins determine the activity, stability, specificity, transportability and lifespan of a protein. Some PTM are highly specific and regulated involving various enzymatic pathways, but there are other non-enzymatic PTM (nePTM), which occur stochastically...

  7. Improved antimelanogenesis and antioxidant effects of polysaccharide from Cuscuta chinensis Lam seeds after enzymatic hydrolysis.

    Science.gov (United States)

    Liu, Zi-Jun; Wang, Ya-Lan; Li, Qi-Ling; Yang, Liu

    2018-01-01

    Cuscuta chinensis polysaccharide (CPS) was extracted using hot water and enzymatically hydrolyzed C. chinensis polysaccharide (ECPS) was produced by the mannase enzymatic hydrolysis process. The purpose of this research was to investigate the antimelanogenic activity of ECPS and CPS in B16F10 melanoma cells. The in vitro antioxidant activity was assessed by their ferric iron reducing power and DPPH free radical scavenging activities. The molecular mass distribution of polysaccharides was determined using SEC-MALLS-RI. CPS was successfully enzymatically degraded using mannase and the weighted average molecular weights of CPS and ECPS were 434.6 kDa and 211.7 kDa. The results of biological activity assays suggested that the enzymatically hydrolyzed polysaccharide had superior antimelanogenic activity and antioxidant effect than the original polysaccharide. ECPS exhibited antimelanogenic activity by down-regulating the expression of tyrosinase, MITF, and TRP-1 without cytotoxic effects in B16F10 melanoma cells. In conclusion, ECPS have the potential to become a skin whitening product.

  8. Kinetics of Enzymatic High-Solid Hydrolysis of Lignocellulosic Biomass Studied by Calorimetry

    DEFF Research Database (Denmark)

    Olsen, Søren Nymand; Rasmussen, Erik Lumby; McFarland, K.C.

    2011-01-01

    analysis of the interrelationships of enzyme load and the rate, time, and extent of the reaction. The results suggest that the hydrolysis rate of pretreated corn stover is limited initially by available attack points on the substrate surface (conversion) but becomes proportional to enzyme dosage......Enzymatic hydrolysis of high-solid biomass (>10% w/w dry mass) has become increasingly important as a key step in the production of second-generation bioethanol. To this end, development of quantitative real-time assays is desirable both for empirical optimization and for detailed kinetic analysis...... rate with a detection limit of about 500 pmol glucose s−1. Hence, calorimetry is shown to be a highly sensitive real-time method, applicable for high solids, and independent on the complexity of the substrate. Dose–response experiments with a typical cellulase cocktail enabled a multidimensional...

  9. PSA-alpha-2-macroglobulin complex is enzymatically active in the serum of patients with advanced prostate cancer and can degrade circulating peptide hormones.

    Science.gov (United States)

    Kostova, Maya B; Brennen, William Nathaniel; Lopez, David; Anthony, Lizamma; Wang, Hao; Platz, Elizabeth; Denmeade, Samuel R

    2018-08-01

    Prostate cancer cells produce high levels of the serine protease Prostate-Specific Antigen (PSA). PSA is enzymatically active in the tumor microenvironment but is presumed to be enzymatically inactive in the blood due to complex formation with serum protease inhibitors α-1-antichymotrypsin and α-2-macroglobulin (A2M). PSA-A2M complexes cannot be measured by standard ELISA assays and are also rapidly cleared from the circulation. Thus the exact magnitude of PSA production by prostate cancer cells is not easily measured. The PSA complexed to A2M is unable to cleave proteins but maintains the ability to cleave small peptide substrates. Thus, in advanced prostate cancer, sufficient PSA-A2M may be in circulation to effect total A2M levels, levels of cytokines bound to A2M and hydrolyze small circulating peptide hormones. Total A2M levels in men with advanced prostate cancer and PSA levels above 1000 ng/mL were measured by ELISA and compared to controls. Additional ELISA assays were used to measure levels of IL-6 and TGF-beta which can bind to A2M. The ability of PSA-A2M complexes to hydrolyze protein and peptide substrates was analyzed ± PSA inhibitor. Enzymatic activity of PSA-A2M in serum of men with high PSA levels was also assayed. Serum A2M levels are inversely correlated with PSA levels in men with advanced prostate cancer. Il-6 Levels are significantly elevated in men with PSA >1000 ng/mL compared to controls with PSA PSA-A2M complex in serum of men with PSA levels >1000 ng/mL can hydrolyze small fluorescently labeled peptide substrates but not large proteins that are PSA substrates. PSA can hydrolyze small peptide hormones like PTHrP and osteocalcin. PSA complexed to A2M retains the ability to degrade PTHrP. In advanced prostate cancer with PSA levels >1000 ng/mL, sufficient PSA-A2M is present in circulation to produce enzymatic activity against circulating small peptide hormones. Sufficient PSA is produced in advanced prostate cancer to alter

  10. Electrodeposition of flower-like platinum on electrophoretically grown nitrogen-doped graphene as a highly sensitive electrochemical non-enzymatic biosensor for hydrogen peroxide detection

    Energy Technology Data Exchange (ETDEWEB)

    Tajabadi, M.T. [University Malaya Centre for Ionic Liquids, Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia); Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia); Sookhakian, M., E-mail: m.sokhakian@gmail.com [University Malaya Centre for Ionic Liquids, Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia); Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia); Department of Mechanical Convergence Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul, 133-791, Korea (Korea, Republic of); Zalnezhad, E., E-mail: erfan@hanyang.ac.kr [Department of Mechanical Convergence Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul, 133-791, Korea (Korea, Republic of); Yoon, G.H. [Department of Mechanical Convergence Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul, 133-791, Korea (Korea, Republic of); Hamouda, A.M.S. [Mechanical and Industrial Engineering Department, College of Engineering, Qatar University, 2713, Doha (Qatar); Azarang, Majid [Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia); Basirun, W.J. [Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia); Institute of Nanotechnology & Catalysis Research, Institute of Postgraduate Studies, University Malaya, 50603 Kuala Lumpur (Malaysia); Alias, Y., E-mail: yatimah70@um.edu.my [University Malaya Centre for Ionic Liquids, Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia); Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia)

    2016-11-15

    Highlights: • Nitrogen doped graphene with different thickness by electrophoretic deposition. • The conductivity of N-graphene layer depends on the tickness. • Support of platinum shows efficient electrocatalytic performance for biosensor. • CV curves and amperometric responses improved and optimized in the presence of N-graphene. - Abstract: An efficient non-enzymatic biosensor electrode consisting of nitrogen-doped graphene (N-graphene) and platinum nanoflower (Pt NF) with different N-graphene loadings were fabricated on indium tin oxide (ITO) glass using a simple layer-by-layer electrophoretic and electrochemical sequential deposition approach. N-graphene was synthesized by annealing graphene oxide with urea at 900 °C. The structure and morphology of the as-fabricated non-enzymatic biosensor electrodes were determined using X-ray diffraction, field emission electron microscopy, transmission electron microscopy, Raman and X-ray photoelectron spectra. The as-fabricated Pt NF-N-graphene-modified ITO electrodes with different N-graphene loadings were utilized as a non-enzymatic biosensor electrode for the detection of hydrogen peroxide (H{sub 2}O{sub 2}). The behaviors of the hybrid electrodes towards H{sub 2}O{sub 2} reduction were assessed using chronoamperometry, cyclic voltammetry and electrochemical impedance spectroscopy analysis. The Pt NF-N-graphene-modified ITO electrode with a 0.05 mg ml{sup −1} N-graphene loading exhibited the lowest detection limit, fastest amperometric sensing, a wide linear response range, excellent stability and reproducibility for the non-enzymatic H{sub 2}O{sub 2} detection, due to the synergistic effect between the electrocatalytic activity of the Pt NF and the high conductivity and large surface area of N-graphene.

  11. Determination of myoglobin based on its enzymatic activity by stopped-flow spectrophotometry

    Science.gov (United States)

    Zheng, Qi; Liu, Zhihong; Cai, Ruxiu

    2005-04-01

    A new method has been developed for the determination of myoglobin (Mb) based on its enzymatic activity for the oxidation of o-phenylenediamine (OPDA) with hydrogen peroxide. Stopped-flow spectrophotometry was used to study the kinetic behavior of the oxidation reaction. The catalytic activity of Mb was compared to other three kinds of catalyst. The time dependent absorbance of the reaction product, 2,3-diamimophenazine (DAPN), at a wavelength of 426 nm was recorded. The initial reaction rate obtained at 40 °C was found to be proportional to the concentration of Mb in the range of 1.0 × 10 -6 to 4.0 × 10 -9 mol L -1. The detection limit of Mb was found to be 9.93 × 10 -10 mol L -1. The relative standard deviations were within 5% for the determination of different concentrations of Mb. Excess of bovine serum albumin (BSA), Ca(II), Mg(II), Cu(II), glucose, caffeine, lactose and uric acid did not interfere.

  12. Enzymatic conversion of all-trans-β-carotene to retinal by a cytosolic enzyme from rabbit and rat intestinal mucosa

    International Nuclear Information System (INIS)

    Lakshman, M.R.; Mychkovsky, I.; Attlesey, M.

    1989-01-01

    Enzymatic conversion of all-trans-β-carotene to retinal by a partially purified enzyme from rabbit and rat intestinal mucosa was demonstrated. The enzymatic product was characterized based on the following evidence: (i) the product gave rise to its O-ethyloxime by treatment with O-ethylhydroxylamine with an absorption maximum at 363 nm in ethanol characteristics of authentic retinal O-ethyloxime. High-pressure liquid chromatography (HPLC) of this derivative yielded a sharp peak with a retention time of 7.99 min corresponding to the authentic compound; (ii) the mass spectrum of the O-ethyloxime of the enzymatic product was identical to that of authentic retinal O-ethyloxime; (iii) the specific activity of the enzymatically formed [ 14 C]retinal O-ethyloxime remained constant even after repeated crystallization; (iv) the enzymatic product exhibited an absorption maximum at 370 nm in light petroleum characteristic of authentic retinal. This retinol was enzymatically esterified to retinyl palmitate by rat pancreatic esterase with a retention time of 10 min on HPLC corresponding to authentic retinyl palmitate. Thus, the enzymatic product of β-carotene cleavage by the partially purified intestinal enzyme was unequivocally confirmed to be retinal

  13. Mitochondrial intermediate peptidase: Expression in Escherichia coli and improvement of its enzymatic activity detection with FRET substrates

    International Nuclear Information System (INIS)

    Marcondes, Marcelo F.; Torquato, Ricardo J.S.; Assis, Diego M.; Juliano, Maria A.; Hayashi, Mirian A.F.; Oliveira, Vitor

    2010-01-01

    In the present study, soluble, functionally-active, recombinant human mitochondrial intermediate peptidase (hMIP), a mitochondrial metalloendoprotease, was expressed in a prokaryotic system. The hMIP fusion protein, with a poly-His-tag (6x His), was obtained by cloning the coding region of hMIP cDNA into the pET-28a expression vector, which was then used to transform Escherichia coli BL21 (DE3) pLysS. After isolation and purification of the fusion protein by affinity chromatography using Ni-Sepharose resin, the protein was purified further using ion exchange chromatography with a Hi-trap resource Q column. The recombinant hMIP was characterized by Western blotting using three distinct antibodies, circular dichroism, and enzymatic assays that used the first FRET substrates developed for MIP and a series of protease inhibitors. The successful expression of enzymatically-active hMIP in addition to the FRET substrates will contribute greatly to the determination of substrate specificity of this protease and to the development of specific inhibitors that are essential for a better understanding of the role of this protease in mitochondrial functioning.

  14. Conferring specificity in redox pathways by enzymatic thiol/disulfide exchange reactions.

    Science.gov (United States)

    Netto, Luis Eduardo S; de Oliveira, Marcos Antonio; Tairum, Carlos A; da Silva Neto, José Freire

    2016-01-01

    Thiol-disulfide exchange reactions are highly reversible, displaying nucleophilic substitutions mechanism (S(N)2 type). For aliphatic, low molecular thiols, these reactions are slow, but can attain million times faster rates in enzymatic processes. Thioredoxin (Trx) proteins were the first enzymes described to accelerate thiol-disulfide exchange reactions and their high reactivity is related to the high nucleophilicity of the attacking thiol. Substrate specificity in Trx is achieved by several factors, including polar, hydrophobic, and topological interactions through a groove in the active site. Glutaredoxin (Grx) enzymes also contain the Trx fold, but they do not share amino acid sequence similarity with Trx. A conserved glutathione binding site is a typical feature of Grx that can reduce substrates by two mechanisms (mono and dithiol). The high reactivity of Grx enzymes is related to the very acid pK(a) values of reactive Cys that plays roles as good leaving groups. Therefore, although distinct oxidoreductases catalyze similar thiol–disulfide exchange reactions, their enzymatic mechanisms vary. PDI and DsbA are two other oxidoreductases, but they are involved in disulfide bond formation, instead of disulfide reduction, which is related to the oxidative environment where they are found. PDI enzymes and DsbC are endowed with disulfide isomerase activity, which is related with their tetra-domain architecture. As illustrative description of specificity in thiol-disulfide exchange, redox aspects of transcription activation in bacteria, yeast, and mammals are presented in an evolutionary perspective. Therefore, thiol-disulfide exchange reactions play important roles in conferring specificity to pathways, a required feature for signaling.

  15. CuO nanoparticles supported on nitrogen and sulfur co-doped graphene nanocomposites for non-enzymatic glucose sensing

    Energy Technology Data Exchange (ETDEWEB)

    Li, Meixia [Hebei University of Engineering, Faculty of Material Science and Engineering (China); Guo, Qingbin, E-mail: guoqingbinhue@163.com [Hebei University of Engineering, Academic Affairs office (China); Xie, Juan; Li, Yongde; Feng, Yapeng [Hebei University of Engineering, Faculty of Material Science and Engineering (China)

    2017-01-15

    Developing highly active catalysts to promote the electrocatalytic glucose oxidation (EGO) is a crucial demand for non-enzymatic glucose sensing. Herein, we reported the use of nitrogen and sulfur co-doped graphene (NSG) as a novel support material for anchoring CuO nanoparticles and obtained CuO/NSG was employed as an efficient EGO catalyst for non-enzymatic glucose sensing. The results showed that the NSG endowed the CuO/NSG with large surface area, increased structural defects, improved conductivity, and strong covalent coupling between NSG and CuO. Owing to the significant contribution of NSG and the synergistic effect of NSG and CuO, the CuO/NSG exhibited a remarkably higher EGO activity than CuO and CuO/reduced graphene oxide. The CuO/NSG-based sensor displayed excellent glucose sensing performances with a considerably low detection limit of 0.07 μM. These findings elucidate that the NSG is a promising support material for non-enzymatic glucose detection.

  16. Enzymatic saccharification of biologically pre-treated wheat straw with white-rot fungi.

    Science.gov (United States)

    Dias, Albino A; Freitas, Gil S; Marques, Guilhermina S M; Sampaio, Ana; Fraga, Irene S; Rodrigues, Miguel A M; Evtuguin, Dmitry V; Bezerra, Rui M F

    2010-08-01

    Wheat straw was submitted to a pre-treatment by the basidiomycetous fungi Euc-1 and Irpex lacteus, aiming to improve the accessibility of cellulose towards enzymatic hydrolysis via previous selective bio-delignification. This allowed the increase of substrate saccharification nearly four and three times while applying the basidiomycetes Euc-1 and I. lacteus, respectively. The cellulose/lignin ratio increased from 2.7 in the untreated wheat straw to 5.9 and 4.6 after the bio-treatment by the basidiomycetes Euc-1 and I. lacteus, respectively, thus evidencing the highly selective lignin biodegradation. The enzymatic profile of both fungi upon bio-treatment of wheat straw have been assessed including laccase, manganese-dependent peroxidase, lignin peroxidase, carboxymethylcellulase, xylanase, avicelase and feruloyl esterase activities. The difference in efficiency and selectivity of delignification within the two fungi treatments was interpreted in terms of specific lignolytic enzyme profiles and moderate xylanase and cellulolytic activities. (c) 2010 Elsevier Ltd. All rights reserved.

  17. Haemoglobin variants may cause significant differences in haemoglobin A1c as measured by high-performance liquid chromatography and enzymatic methods in diabetic patients: a cross-sectional study.

    Science.gov (United States)

    Otabe, Shuichi; Nakayama, Hitomi; Ohki, Tsuyoshi; Soejima, Eri; Tajiri, Yuji; Yamada, Kentaro

    2017-07-01

    Background We aimed to determine whether the discrepancy between haemoglobin A1c values determined by high-performance liquid chromatography and enzymatic haemoglobin A1c measurements in diabetic patients was clinically relevant. Methods We randomly recruited 1421 outpatients undergoing diabetic treatment and follow-up who underwent at least three haemoglobin A1c measurements between April 2014 and March 2015 at our clinic. In 6369 samples, haemoglobin A1c was simultaneously measured by HA-8160 and MetaboLead (enzymatic assay), and the values were compared. Results haemoglobin A1c measurements by high-performance liquid chromatography and enzymatic assay were strongly correlated (correlation coefficient: 0.9828, linear approximation curve y = 0.9986x - 0.2507). Mean haemoglobin A1c (6.8 ± 1.0%) measured by high-performance liquid chromatography was significantly higher than that measured by enzymatic assay (6.5 ± 1.0%, P liquid chromatography than those from enzymatic assay. Of these, three had Hb Toranomon [β112 (G14) Cys→Trp]. The fourth had Hb Ube-2 [α68 (E17) Asn→Asp]. One other subject presented consistently higher haemoglobin A1c values (>1%) by high-performance liquid chromatography than those from enzymatic assay and was diagnosed with a -77 (T > C) mutation in the δ-globin gene. These unrelated asymptomatic subjects had normal erythrocyte profiles, without anaemia. Conclusions We showed that haemoglobin A1c values measured by high-performance liquid chromatography were significantly higher than those measured by enzymatic assay in diabetic subjects. However, when an oversized deviation (>0.7%) between glycaemic control status and haemoglobin A1c is apparent, clinicians should check the methods used to measure haemoglobin A1c and consider the possible presence of a haemoglobin variant.

  18. Application of enzymatic methods for chia (Salvia hispanica L oil extraction

    Directory of Open Access Journals (Sweden)

    Norma Ciau-Solís

    2016-07-01

    Full Text Available Aim. The aim was to evaluate the use of different enzymatic treatments on the oil extraction yield from Chia (Salvia hispanica L. seeds Methods. Enzymatic extraction was performed by treating of whole and degummed chia flours with different conditions of enzyme concentration, pH and temperature. Commercial enzymes were employed: Viscozyme LTM (endo-1,3 (4-betaglucanase derived from Aspergillus aculeatus, with 100 FBG g (Beta Glucanase-unit Fungal and Neutrase0.8LTM, neutral protease with 0.8 AU-NH/g of activity, derived from Bacillus amyloliquefaciens. Results. All treatments of enzymatic oil extraction were different (P <0.05 and the maximum oil yield obtained was 9.35%. Conclusion. Oil extraction using enzymatic methods is not a viable for chia seed

  19. Phospholipase C produced by Clostridium botulinum types C and D: comparison of gene, enzymatic, and biological activities with those of Clostridium perfringens alpha-toxin.

    Science.gov (United States)

    Fatmawati, Ni Nengah Dwi; Sakaguchi, Yoshihiko; Suzuki, Tomonori; Oda, Masataka; Shimizu, Kenta; Yamamoto, Yumiko; Sakurai, Jun; Matsushita, Osamu; Oguma, Keiji

    2013-01-01

    Clostridium botulinum type C and D strains recently have been found to produce PLC on egg yolk agar plates. To characterize the gene, enzymatic and biological activities of C. botulinum PLCs (Cb-PLCs), the cb-plc genes from 8 strains were sequenced, and 1 representative gene was cloned and expressed as a recombinant protein. The enzymatic and hemolytic activities of the recombinant Cb-PLC were measured and compared with those of the Clostridium perfringens alpha-toxin. Each of the eight cb-plc genes encoded a 399 amino acid residue protein preceded by a 27 residue signal peptide. The protein consists of 2 domains, the N- and C-domains, and the overall amino acid sequence identity between Cb-PLC and alpha-toxin was greater than 50%, suggesting that Cb-PLC is homologous to the alpha-toxin. The key residues in the N-domain were conserved, whereas those in the C-domain which are important in membrane interaction were different than in the alpha-toxin. As expected, Cb-PLC could hydrolyze egg yolk phospholipid, p-nitrophenylphosphorylcholine, and sphingomyelin, and also exhibited hemolytic activity;however, its activities were about 4- to over 200-fold lower than those of alpha-toxin. Although Cb-PLC showed weak enzymatic and biological activities, it is speculated that Cb-PLC might play a role in the pathogenicity of botulism or for bacterial survival.

  20. Evaluation of Oil Removal Efficiency and Enzymatic Activity in Some fungal Strains for Bioremediation of Petroleum-Polluted Soils

    Directory of Open Access Journals (Sweden)

    Fariba Mohsenzadeh

    2012-12-01

    Full Text Available Background: Petroleum pollution is a global disaster and there are several soil cleaning methods including bioremediation.Methods: In a field study, fugal strains were isolated from oil-contaminated sites of Arak refinery (Iran and their growth ability was checked in potato dextrose agar (PDA media containing 0-10% v/v crude oil, the activity of three enzymes (Catalase, Peroxidase and Phenol Oxidase was evaluated in the fungal colonies and bioremediation ability of the fungi was checked in the experimental pots containing 3 kg sterilized soil and different concentrations of petroleum (0-10% w/w.Results: Four fungal strains, Acromonium sp., Alternaria sp., Aspergillus terreus and Penicillium sp., were selected asthe most resistant ones. They were able to growth in the subjected concentrations and Alternaria sp. showed thehighest growth ability in the petroleum containing media. The enzyme assay showed that the enzymatic activity was increased in the oil-contaminated media. Bioremediation results showed that the studied fungi were able to decrease petroleum pollution. The highest petroleum removing efficiency of Aspergillus terreus, Penicillium sp.,Alternaria sp. and Acromonium sp. was evaluated in the 10%, 8%, 8% and 2% petroleum pollution respectively.Conclusions: Fungi are important microorganisms in decreasing of petroleum pollution. They have bioremediation potency that is related to their enzymatic activities.

  1. Evaluation of physical structural features on influencing enzymatic hydrolysis efficiency of micronized wood

    Science.gov (United States)

    Jinxue Jiang; Jinwu Wang; Xiao Zhang; Michael Wolcott

    2016-01-01

    Enzymatic hydrolysis of lignocellulosic biomass is highly dependent on the changes in structural features after pretreatment. Mechanical milling pretreatment is an effective approach to alter the physical structure of biomass and thus improve enzymatic hydrolysis. This study examined the influence of structural characteristics on the enzymatic hydrolysis of micronized...

  2. A δ38 deletion variant of human transketolase as a model of transketolase-like protein 1 exhibits no enzymatic activity.

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    Stefan Schneider

    Full Text Available Besides transketolase (TKT, a thiamin-dependent enzyme of the pentose phosphate pathway, the human genome encodes for two closely related transketolase-like proteins, which share a high sequence identity with TKT. Transketolase-like protein 1 (TKTL1 has been implicated in cancerogenesis as its cellular expression levels were reported to directly correlate with invasion efficiency of cancer cells and patient mortality. It has been proposed that TKTL1 exerts its function by catalyzing an unusual enzymatic reaction, a hypothesis that has been the subject of recent controversy. The most striking difference between TKTL1 and TKT is a deletion of 38 consecutive amino acids in the N-terminal domain of the former, which constitute part of the active site in authentic TKT. Our structural and sequence analysis suggested that TKTL1 might not possess transketolase activity. In order to test this hypothesis in the absence of a recombinant expression system for TKTL1 and resilient data on its biochemical properties, we have engineered and biochemically characterized a "pseudo-TKTL1" Δ38 deletion variant of human TKT (TKTΔ38 as a viable model of TKTL1. Although the isolated protein is properly folded under in vitro conditions, both thermal stability as well as stability of the TKT-specific homodimeric assembly are markedly reduced. Circular dichroism and NMR spectroscopic analysis further indicates that TKTΔ38 is unable to bind the thiamin cofactor in a specific manner, even at superphysiological concentrations. No transketolase activity of TKTΔ38 can be detected for conversion of physiological sugar substrates thus arguing against an intrinsically encoded enzymatic function of TKTL1 in tumor cell metabolism.

  3. Co3O4 based non-enzymatic glucose sensor with high sensitivity and reliable stability derived from hollow hierarchical architecture

    Science.gov (United States)

    Tian, Liangliang; He, Gege; Cai, Yanhua; Wu, Shenping; Su, Yongyao; Yan, Hengqing; Yang, Cong; Chen, Yanling; Li, Lu

    2018-02-01

    Inspired by kinetics, the design of hollow hierarchical electrocatalysts through large-scale integration of building blocks is recognized as an effective approach to the achievement of superior electrocatalytic performance. In this work, a hollow, hierarchical Co3O4 architecture (Co3O4 HHA) was constructed using a coordinated etching and precipitation (CEP) method followed by calcination. The resulting Co3O4 HHA electrode exhibited excellent electrocatalytic activity in terms of high sensitivity (839.3 μA mM-1 cm-2) and reliable stability in glucose detection. The high sensitivity could be attributed to the large specific surface area (SSA), ample unimpeded penetration diffusion paths and high electron transfer rate originating from the unique two-dimensional (2D) sheet-like character and hollow porous architecture. The hollow hierarchical structure also affords sufficient interspace for accommodation of volume change and structural strain, resulting in enhanced stability. The results indicate that Co3O4 HHA could have potential for application in the design of non-enzymatic glucose sensors, and that the construction of hollow hierarchical architecture provides an efficient way to design highly active, stable electrocatalysts.

  4. Warming and organic matter sources impact the proportion of dissolved to total activities in marine extracellular enzymatic rates

    KAUST Repository

    Baltar, Federico

    2017-04-19

    Extracellular enzymatic activities (EEAs) are the rate-limiting step in the degradation of organic matter. Extracellular enzymes can be found associated to cells or dissolved in the surrounding water. The proportion of cell-free EEA constitutes in many marine environments more than half of the total activity. This high proportion causes an uncoupling between hydrolysis rates and the actual bacterial activity. However, we do not know what factors control the proportion of dissolved relative to total EEA, nor how this may change in the future ocean. To resolve this, we performed laboratory experiments with water from the Great Barrier Reef (Australia) to study the effects of temperature and dissolved organic matter sources on EEA and the proportion of dissolved EEA. We found that warming increases the rates of organic matter hydrolysis and reduces the proportion of dissolved relative to total EEA. This suggests a potential increase of the coupling between organic matter hydrolysis and heterotrophic activities with increasing ocean temperatures, although strongly dependent on the organic matter substrates available. Our study suggests that local differences in the organic matter composition in tropical coastal ecosystems will strongly affect the proportion of dissolved EEA in response to ocean warming.

  5. A rapid enzymatic assay for high-throughput screening of adenosine-producing strains

    Science.gov (United States)

    Dong, Huina; Zu, Xin; Zheng, Ping; Zhang, Dawei

    2015-01-01

    Adenosine is a major local regulator of tissue function and industrially useful as precursor for the production of medicinal nucleoside substances. High-throughput screening of adenosine overproducers is important for industrial microorganism breeding. An enzymatic assay of adenosine was developed by combined adenosine deaminase (ADA) with indophenol method. The ADA catalyzes the cleavage of adenosine to inosine and NH3, the latter can be accurately determined by indophenol method. The assay system was optimized to deliver a good performance and could tolerate the addition of inorganic salts and many nutrition components to the assay mixtures. Adenosine could be accurately determined by this assay using 96-well microplates. Spike and recovery tests showed that this assay can accurately and reproducibly determine increases in adenosine in fermentation broth without any pretreatment to remove proteins and potentially interfering low-molecular-weight molecules. This assay was also applied to high-throughput screening for high adenosine-producing strains. The high selectivity and accuracy of the ADA assay provides rapid and high-throughput analysis of adenosine in large numbers of samples. PMID:25580842

  6. Role of low density lipoprotein in the activation of plasma lysolecithin acyltransferase activity. Effect of chemical and enzymatic modifications of the lipoprotein on enzyme activity.

    Science.gov (United States)

    Subbaiah, P V; Chen, C H; Bagdade, J D; Albers, J J

    1985-01-01

    The effect of various chemical and enzymatic modifications of low density lipoprotein (LDL) on its ability to activate the isolated human plasma lysolecithin acyltransferase (LAT) was studied. Removal of all lipids from LDL resulted in the complete loss of LAT activation. Removal of only neutral lipids by extraction with heptane retained up to 50% of the original activity, which was not increased further by reconstitution of the LDL with the extracted lipids. Hydrolysis of the diacylphosphoglycerides of the LDL with phospholipases resulted in complete loss of LAT activation which was partially restored by the addition of egg lecithin. Hydrolysis of more than 4% of LDL protein by trypsin led to a linear decrease in activity with complete loss of activity occurring when about 25% of the LDL protein is hydrolyzed. Modification of the arginine groups of LDL reversibly inhibited the activation of LAT. Modification of lysine residues of LDL by acetylation, acetoacetylation or succinylation also abolished its ability to activate lysolecithin acylation.

  7. Assessment of Napropamide Dissipation and its Effect on Soil Enzymatic Activity

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    Mirosław Onyszko

    2017-11-01

    Full Text Available This paper assesses the dissipation of napropamide and its impact on the activity of dehydrogenases, alkaline phosphatase, acid phosphatase, and urease in sandy clay loam. The experiment was carried out on soil samples with organic carbon content of 12.08 g·kg-1, total nitrogen content of 0.97 g·kg-1, and pH 5.24 with the following variable factors: (a dose of Devrinol 450 SC formation (containing 450 g of napropamide in dm3: 0 (control, 0.5, 1, 2, 4, 8, and 16-fold hold of field dose; (b day of experiment: 1, 7, 14, 28, 56, and 112. The half-life of napropamide ranged from 33.50 to 71.42 days. The use of napropamide at the dose recommended by the manufacturer and at the dose reduced by half appeared to exhibit low toxicity in relation to enzymes determined. In contrast, the application of elevated napropamide doses decreased the values of biochemical parameters of the soil in most cases. The Pearson correlation coefficients showed statistically significant negative correlation between the content of napropamide residues and the enzymatic activity of the soil.

  8. The effect of high pressure on the intracellular trehalose synthase activity of Thermus aquaticus.

    Science.gov (United States)

    Dong, Yongsheng; Ma, Lei; Duan, Yuanliang

    2016-01-01

    To understand the effect of high pressure on the intracellular trehalose synthase activity, Thermus aquaticus (T. aquaticus) in the logarithmic growth phase was treated with high-pressure air, and its intracellular trehalose synthase (TSase) activity was determined. Our results indicated that pressure is a factor strongly affecting the cell growth. High pressure significantly attenuated the growth rate of T. aquaticus and shortened the duration of stationary phase. However, after 2 h of culture under 1.0 MPa pressure, the activity of intracellular TSase in T. aquaticus reached its maximum value, indicating that pressure can significantly increase the activity of intracellular TSase in T. aquaticus. Thus the present study provides an important guide for the enzymatic production of trehalose.

  9. Beneficial effect of mixture of additives amendment on enzymatic activities, organic matter degradation and humification during biosolids co-composting.

    Science.gov (United States)

    Awasthi, Mukesh Kumar; Wang, Quan; Chen, Hongyu; Awasthi, Sanjeev Kumar; Wang, Meijing; Ren, Xiuna; Zhao, Junchao; Zhang, Zengqiang

    2018-01-01

    The objective of this study was to identify the effect of mixture of additives to improve the enzymatic activities, organic matter humification and diminished the bioavailability of heavy metals (HMs) during biosolids co-composting. In this study, zeolite (Z) (10%, 15% and 30%) with 1%lime (L) (dry weight basis of biosolids) was blended into the mixture of biosolids and wheat straw, respectively. The without any amendment and 1%lime applied treatments were run for comparison (Control). The Z+L addition resulted rapid organic matter degradation and humification with maximum enzymatic activities. In addition, higher dosage of Z+1%L amendment reduced the bioavailability of HMs (Cu and Zn) and improved the end product quality as compared to control and 1%L applied treatments. However, the 30%Z+1%L applied treatment showed maximum humification and low bioavailability of HMs but considering the economic feasibility and compost quality results, the treatment with 10%Z+1%L is recommended for biosolids co-composting. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Therapeutic effectiveness of a new enzymatic bleaching dentifrice.

    Science.gov (United States)

    Forner, Leopaldo; Amengual, José; Liena, Carmen; Riutord, Pere

    2012-01-01

    Research into bleaching focuses on new products in order to minimize undesirable effects. This study evaluated the bleaching effectiveness of a new enzymatic-activated dentifrice. A total of 20 volunteers were bleached with a dentifrice containing 5% lactoperoxidase and 3% carbamide peroxide applied three times a day for two minutes over 21 days. Color was recorded before and after the treatment using a spectrophotometer. CIELAB differences were calculated before and after treatment using the paired t test (P whitening teeth. Enzymatic dental bleaching is able to increase the efficiency of low concentration peroxides, reducing the potential risk of peroxides on oral tissues.

  11. Enzymatic processing of pigmented and non pigmented rice bran on changes in oryzanol, polyphenols and antioxidant activity.

    Science.gov (United States)

    Prabhu, Ashish A; Jayadeep, A

    2015-10-01

    Bran from different rice varieties is a treasure of nutrients and nutraceuticals, and its use is limited due to the poor sensory and functional properties. Application of enzymes can alter the functional and phytochemical properties. So the effect of endo-xylanase, cellulase and their combination on microstructural, nutraceutical and antioxidant properties of pigmented (Jyothi) and non-pigmented (IR64) rice bran were investigated. Scanning electron micrograph revealed micro structural changes in fibre structures on processing. All the enzymatic processing methods resulted in an increase in the content of oryzanol, soluble, bound and total polyphenols, flavonoid and tannin. It also showed an increase in the bioactivity with respect to free radical scavenging activity and total antioxidant activity. However, extent of the increase in bio-actives varied with the type of bran and enzyme application method. Endo-xylanase showed higher percentage difference compared to controls of Jyothi and IR64 bran extracts respectively in the content of the bound (10 & 19 %) and total (20 & 14 %) polyphenols. Combination of both the enzymes resulted in higher percentage increase of bioactive components and properties. It resulted in greater percentage difference compared to controls of Jyothi and IR64 extracts respectively in the content of soluble (58 & 17 %) and total (21 & 14 %) polyphenols, flavonoids (12 & 38 %), γ-oryzanol (10 & 12 %), free radical scavenging activity (64 & 30 %) and total antioxidant activity (82 & 136 %). It may be concluded that enzymatic bio-processing of bran with cellulose and hemicellulose degrading enzymes can improve its nutraceutical properties, and it may be used for development of functional foods.

  12. Proximity-activated nanoparticles: in vitro performance of specific structural modification by enzymatic cleavage

    Science.gov (United States)

    Adam Smith, R; Sewell, Sarah L; Giorgio, Todd D

    2008-01-01

    The development and in vitro performance of a modular nanoscale system capable of specific structural modification by enzymatic activity is described in this work. Due to its small physical size and adaptable characteristics, this system has the potential for utilization in targeted delivery systems and biosensing. Nanoparticle probes were synthesized containing two distinct fluorescent species including a quantum dot base particle and fluorescently labeled cleavable peptide substrate. Activity of these probes was monitored by gel electrophoresis with quantitative cleavage measurements made by fluorometric analysis. The model proximity-activated nanoparticles studied here exhibit significant susceptibility to cleavage by matrix metalloprotease-7 (MMP-7) at physiologically relevant concentrations, with nearly complete cleavage of available substrate molecules after 24 hours. This response is specific to MMP-7 enzyme activity, as cleavage is completely inhibited with the addition of EDTA. Utilization of enzyme-specific modification is a sensitive approach with broad applications for targeted therapeutics and biosensing. The versatility of this nanoparticle system is highlighted in its modular design, as it has the capability to integrate characteristics for detection, biosensing, targeting, and payload delivery into a single, multifunctional nanoparticle structure. PMID:18488420

  13. Screening for Genes Coding for Putative Antitumor Compounds, Antimicrobial and Enzymatic Activities from Haloalkalitolerant and Haloalkaliphilic Bacteria Strains of Algerian Sahara Soils

    Directory of Open Access Journals (Sweden)

    Okba Selama

    2014-01-01

    Full Text Available Extreme environments may often contain unusual bacterial groups whose physiology is distinct from those of normal environments. To satisfy the need for new bioactive pharmaceuticals compounds and enzymes, we report here the isolation of novel bacteria from an extreme environment. Thirteen selected haloalkalitolerant and haloalkaliphilic bacteria were isolated from Algerian Sahara Desert soils. These isolates were screened for the presence of genes coding for putative antitumor compounds using PCR based methods. Enzymatic, antibacterial, and antifungal activities were determined by using cultural dependant methods. Several of these isolates are typical of desert and alkaline saline soils, but, in addition, we report for the first time the presence of a potential new member of the genus Nocardia with particular activity against the yeast Saccharomyces cerevisiae. In addition to their haloalkali character, the presence of genes coding for putative antitumor compounds, combined with the antimicrobial activity against a broad range of indicator strains and their enzymatic potential, makes them suitable for biotechnology applications.

  14. Immobilization of proteins onto microbeads using a DNA binding tag for enzymatic assays.

    Science.gov (United States)

    Kojima, Takaaki; Mizoguchi, Takuro; Ota, Eri; Hata, Jumpei; Homma, Keisuke; Zhu, Bo; Hitomi, Kiyotaka; Nakano, Hideo

    2016-02-01

    A novel DNA-binding protein tag, scCro-tag, which is a single-chain derivative of the bacteriophage lambda Cro repressor, has been developed to immobilize proteins of interest (POI) on a solid support through binding OR consensus DNA (ORC) that is tightly bound by the scCro protein. The scCro-tag successfully bound a transglutaminase 2 (TGase 2) substrate and manganese peroxidase (MnP) to microbeads via scaffolding DNA. The resulting protein-coated microbeads can be utilized for functional analysis of the enzymatic activity using flow cytometry. The quantity of bead-bound proteins can be enhanced by increasing the number of ORCs. In addition, proteins with the scCro-tag that were synthesized using a cell-free protein synthesis system were also immobilized onto the beads, thus indicating that this bead-based system would be applicable to high-throughput analysis of various enzymatic activities. Copyright © 2015 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  15. Conformational changes in a hyperthermostable glycoside hydrolase: enzymatic activity is a consequence of the loop dynamics and protonation balance.

    Directory of Open Access Journals (Sweden)

    Leandro C de Oliveira

    Full Text Available Endo-β-1, 4-mannanase from Thermotoga petrophila (TpMan is a modular hyperthermostable enzyme involved in the degradation of mannan-containing polysaccharides. The degradation of these polysaccharides represents a key step for several industrial applications. Here, as part of a continuing investigation of TpMan, the region corresponding to the GH5 domain (TpManGH5 was characterized as a function of pH and temperature. The results indicated that the enzymatic activity of the TpManGH5 is pH-dependent, with its optimum activity occurring at pH 6. At pH 8, the studies demonstrated that TpManGH5 is a molecule with a nearly spherical tightly packed core displaying negligible flexibility in solution, and with size and shape very similar to crystal structure. However, TpManGH5 experiences an increase in radius of gyration in acidic conditions suggesting expansion of the molecule. Furthermore, at acidic pH values, TpManGH5 showed a less globular shape, probably due to a loop region slightly more expanded and flexible in solution (residues Y88 to A105. In addition, molecular dynamics simulations indicated that conformational changes caused by pH variation did not change the core of the TpManGH5, which means that only the above mentioned loop region presents high degree of fluctuations. The results also suggested that conformational changes of the loop region may facilitate polysaccharide and enzyme interaction. Finally, at pH 6 the results indicated that TpManGH5 is slightly more flexible at 65°C when compared to the same enzyme at 20°C. The biophysical characterization presented here is well correlated with the enzymatic activity and provide new insight into the structural basis for the temperature and pH-dependent activity of the TpManGH5. Also, the data suggest a loop region that provides a starting point for a rational design of biotechnological desired features.

  16. Quinolone resistance-associated amino acid substitutions affect enzymatic activity of Mycobacterium leprae DNA gyrase.

    Science.gov (United States)

    Yamaguchi, Tomoyuki; Yokoyama, Kazumasa; Nakajima, Chie; Suzuki, Yasuhiko

    2017-07-01

    Quinolones are important antimicrobials for treatment of leprosy, a chronic infectious disease caused by Mycobacterium leprae. Although it is well known that mutations in DNA gyrase are responsible for quinolone resistance, the effect of those mutations on the enzymatic activity is yet to be studied in depth. Hence, we conducted in vitro assays to observe supercoiling reactions of wild type and mutated M. leprae DNA gyrases. DNA gyrase with amino acid substitution Ala91Val possessed the highest activity among the mutants. DNA gyrase with Gly89Cys showed the lowest level of activity despite being found in clinical strains, but it supercoiled DNA like the wild type does if applied at a sufficient concentration. In addition, patterns of time-dependent conversion from relaxed circular DNA into supercoiled DNA by DNA gyrases with clinically unreported Asp95Gly and Asp95Asn were observed to be distinct from those by the other DNA gyrases.

  17. Enzymatic browning and antioxidant activities in harvested litchi fruit as influenced by apple polyphenols.

    Science.gov (United States)

    Zhang, Zhengke; Huber, Donald J; Qu, Hongxia; Yun, Ze; Wang, Hui; Huang, Zihui; Huang, Hua; Jiang, Yueming

    2015-03-15

    'Guiwei' litchi fruit were treated with 5 ga.i. L(-1) apple polyphenols (APP) and then stored at 25°C to investigate the effects on pericarp browning. APP treatment effectively reduced pericarp browning and retarded the loss of red colour. APP-treated fruit exhibited higher levels of anthocyanins and cyanidin-3-rutinoside, which correlated with suppressed anthocyanase activity. APP treatment also maintained membrane integrity and reduced oxidative damage, as indicated by a lower relative leakage rate, malondialdehyde content, and reactive oxygen species (ROS) generation. The data suggest that decompartmentalisation of peroxidase and polyphenoloxidase and respective browning substrates was reduced. In addition, APP treatment enhanced the activities of antioxidant enzymes (superoxide dismutase, catalase, ascorbate peroxidase and glutathione reductase), as well as non-enzymatic antioxidant capacity (DPPH radical-scavenging activity and reducing power), which might be beneficial in scavenging ROS. We propose that APP treatment is a promising safe strategy for controlling postharvest browning of litchi fruit. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. High throughput, high resolution enzymatic lithography process: effect of crystallite size, moisture, and enzyme concentration.

    Science.gov (United States)

    Mao, Zhantong; Ganesh, Manoj; Bucaro, Michael; Smolianski, Igor; Gross, Richard A; Lyons, Alan M

    2014-12-08

    By bringing enzymes into contact with predefined regions of a surface, a polymer film can be selectively degraded to form desired patterns that find a variety of applications in biotechnology and electronics. This so-called "enzymatic lithography" is an environmentally friendly process as it does not require actinic radiation or synthetic chemicals to develop the patterns. A significant challenge to using enzymatic lithography has been the need to restrict the mobility of the enzyme in order to maintain control of feature sizes. Previous approaches have resulted in low throughput and were limited to polymer films only a few nanometers thick. In this paper, we demonstrate an enzymatic lithography system based on Candida antartica lipase B (CALB) and poly(ε-caprolactone) (PCL) that can resolve fine-scale features, (<1 μm across) in thick (0.1-2.0 μm) polymer films. A Polymer Pen Lithography (PPL) tool was developed to deposit an aqueous solution of CALB onto a spin-cast PCL film. Immobilization of the enzyme on the polymer surface was monitored using fluorescence microscopy by labeling CALB with FITC. The crystallite size in the PCL films was systematically varied; small crystallites resulted in significantly faster etch rates (20 nm/min) and the ability to resolve smaller features (as fine as 1 μm). The effect of printing conditions and relative humidity during incubation is also presented. Patterns formed in the PCL film were transferred to an underlying copper foil demonstrating a "Green" approach to the fabrication of printed circuit boards.

  19. Visualization of red-ox proteins on the gold surface using enzymatic polypyrrole formation

    International Nuclear Information System (INIS)

    Ramanaviciene, A.; Kausaite-Minkstimiene, A.; Voronovic, J.; Ramanavicius, A.; Oztekin, Y.; Carac, G.; German, N.

    2011-01-01

    We describe a new method for the visualization of the activity of red-ox proteins on a gold interface. Glucose oxidase was selected as a model system. Surfaces were modified by adhesion of glucose oxidase on (a) electrochemically cleaned gold; (b) gold films modified with gold nanoparticles, (c) a gold surface modified with self-assembled monolayer, and (d) covalent immobilization of protein on the gold surface modified with a self-assembled monolayer. The simple optical method for the visualization of enzyme on the surfaces is based on the enzymatic formation of polypyrrole. The activity of the enzyme was quantified via enzymatic formation of polypyrrole, which was detected and investigated by quartz microbalance and amperometric techniques. The experimental data suggest that the enzymatic formation of the polymer may serve as a method to indicate the adhesion of active redox enzyme on such surfaces. (author)

  20. The Membrane-anchored Serine Protease Prostasin (CAP1/PRSS8) Supports Epidermal Development and Postnatal Homeostasis Independent of Its Enzymatic Activity

    DEFF Research Database (Denmark)

    Peters, Diane E; Szabo, Roman; Friis, Stine

    2014-01-01

    The membrane-anchored serine protease prostasin (CAP1/PRSS8) is part of a cell surface proteolytic cascade that is essential for epithelial barrier formation and homeostasis. Here, we report the surprising finding that prostasin executes these functions independent of its own enzymatic activity. ...

  1. Production of xylooligosaccharide from wheat bran by microwave assisted enzymatic hydrolysis.

    Science.gov (United States)

    Wang, Tseng-Hsing; Lu, Shin

    2013-06-01

    The effective production of xylooligosaccharides (XOS) from wheat bran was investigated. Wheat bran contains rich hemicellulose which can be hydrolyzed by enzyme; the XOS were obtained by microwave assisted enzymatic hydrolysis. To improve the productivity of XOS, repeated microwave assisted enzymatic hydrolysis and activated carbon adsorption method was chosen to eliminate macromolecules in the XOS. On the basis of experimental data, an industrial XOS production process consisting of pretreatment, repeated microwave assisted enzymatic treatment and purification was designed. Using the designed process, 3.2g dry of purified XOS was produced from 50 g dry wheat bran powder. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. Evaluation of oil removal efficiency and enzymatic activity in some fungal strains for bioremediation of petroleum-polluted soils

    Directory of Open Access Journals (Sweden)

    Mohsenzadeh Fariba

    2012-12-01

    Full Text Available Abstract Background Petroleum pollution is a global disaster and there are several soil cleaning methods including bioremediation. Methods In a field study, fugal strains were isolated from oil-contaminated sites of Arak refinery (Iran and their growth ability was checked in potato dextrose agar (PDA media containing 0-10% v/v crude oil, the activity of three enzymes (Catalase, Peroxidase and Phenol Oxidase was evaluated in the fungal colonies and bioremediation ability of the fungi was checked in the experimental pots containing 3 kg sterilized soil and different concentrations of petroleum (0-10% w/w. Results Four fungal strains, Acromonium sp., Alternaria sp., Aspergillus terreus and Penicillium sp., were selected as the most resistant ones. They were able to growth in the subjected concentrations and Alternaria sp. showed the highest growth ability in the petroleum containing media. The enzyme assay showed that the enzymatic activity was increased in the oil-contaminated media. Bioremediation results showed that the studied fungi were able to decrease petroleum pollution. The highest petroleum removing efficiency of Aspergillus terreus, Penicillium sp., Alternaria sp. and Acromonium sp. was evaluated in the 10%, 8%, 8% and 2% petroleum pollution respectively. Conclusions Fungi are important microorganisms in decreasing of petroleum pollution. They have bioremediation potency that is related to their enzymatic activities.

  3. Kinetic modelling of enzymatic starch hydrolysis

    NARCIS (Netherlands)

    Bednarska, K.A.

    2015-01-01

    Kinetic modelling of enzymatic starch hydrolysis – a summary

    K.A. Bednarska

    The dissertation entitled ‘Kinetic modelling of enzymatic starch hydrolysis’ describes the enzymatic hydrolysis and kinetic modelling of liquefaction and saccharification of wheat starch.

  4. Impact of the redox-cycling herbicide diquat on transcript expression and antioxidant enzymatic activities of the freshwater snail Lymnaea stagnalis

    Energy Technology Data Exchange (ETDEWEB)

    Bouetard, Anthony, E-mail: anthony.bouetard@rennes.inra.fr [INRA, UMR INRA-Agrocampus Ouest ESE 0985, Equipe Ecotoxicologie et Qualite des Milieux Aquatiques, 65 rue de Saint-Brieuc, 35042 Rennes cedex (France); Besnard, Anne-Laure; Vassaux, Daniele; Lagadic, Laurent; Coutellec, Marie-Agnes [INRA, UMR INRA-Agrocampus Ouest ESE 0985, Equipe Ecotoxicologie et Qualite des Milieux Aquatiques, 65 rue de Saint-Brieuc, 35042 Rennes cedex (France)

    2013-01-15

    The presence of pesticides in the environment results in potential unwanted effects on non-target species. Freshwater organisms inhabiting water bodies adjacent to agricultural areas, such as ditches, ponds and marshes, are good models to test such effects as various pesticides may reach these habitats through several ways, including aerial drift, run-off, and drainage. Diquat is a non-selective herbicide used for crop protection or for weed control in such water bodies. In this study, we investigated the effects of diquat on a widely spread aquatic invertebrate, the holarctic freshwater snail Lymnaea stagnalis. Due to the known redox-cycling properties of diquat, we studied transcript expression and enzymatic activities relative to oxidative and general stress in the haemolymph and gonado-digestive complex (GDC). As diquat is not persistent, snails were exposed for short times (5, 24, and 48 h) to ecologically relevant concentrations (22.2, 44.4, and 222.2 {mu}g l{sup -1}) of diquat dibromide. RT-qPCR was used to quantify the transcription of genes encoding catalase (cat), a cytosolic superoxide dismutase (Cu/Zn-sod), a selenium-dependent glutathione peroxidase (gpx), a glutathione reductase (gred), the retinoid X receptor (rxr), two heat shock proteins (hsp40 and hsp70), cortactin (cor) and the two ribosomal genes r18S and r28s. Enzymatic activities of SOD, Gpx, Gred and glutathione S-transferase (GST) were investigated in the GDC using spectrophoto/fluorometric methods. Opposite trends were obtained in the haemolymph depending on the herbicide concentration. At the lowest concentration, effects were mainly observed after 24 h of exposure, with over-transcription of cor, hsp40, rxr, and sod, whereas higher concentrations down-regulated the expression of most of the studied transcripts, especially after 48 h of exposure. In the GDC, earlier responses were observed and the fold-change magnitude was generally much higher: transcription of all target genes increased

  5. Effects of treated industrial wastewaters and temperatures on growth and enzymatic activities of duckweed (Lemna minor L.).

    Science.gov (United States)

    Basiglini, E; Pintore, M; Forni, C

    2018-05-30

    The efficacy of the removal of contaminants from wastewater depends on physico-chemical properties of pollutants and the efficiency of treatment plant. Sometimes, low amounts of toxic compounds can be still present in the treated sewage. In this work we considered the effects of contaminant residues in treated wastewaters and of temperatures on Lemna minor L. Treated effluent waters were collected, analyzed and used as duckweed growth medium. In order to better understand the effects of micropollutants and seasonal variation, the plants were grown under ambient conditions for seven days in summer and winter. Relative growth rate, pigments and phenolic compounds concentrations were determined, as well as the activities of catalase (CAT), ascorbate peroxidase (APX), guaiacol peroxidase (G-POD) and polyphenol oxidase (PPO). The pollutant concentrations varied in the two seasons, depending on the industrial and municipal activities and efficiency of treatments. Treated waters contained heavy metals, nitrogenous and phosphorus compounds, surfactants and hydrocarbons. Compared to the control, duckweed growth of treated plants decreased by 25% in summer, while in the winter due to the lower temperatures and the presence of pollutants was completely impeded. The amounts of photosynthetic pigments of treated plants were not significantly affected in the summer, while they were higher than the control in the winter when the effluent had a high nitrogen amount. High CAT activity was registered in both seasons. Treated plants had significantly lower APX activity in the summer (53%) and winter (59%) respect to the controls. The observed inhibition of the peroxidase activities in the exposed plants, confirms the controversy existing in the literature about the variability of enzymatic response in stress condition. Copyright © 2018 Elsevier Inc. All rights reserved.

  6. Enzymatic hydrolysis and ethanol fermentation of high dry matter wet-exploded wheat straw at low enzyme loading

    DEFF Research Database (Denmark)

    Georgieva, T.I.; Hou, Xiaoru; Hilstrøm, Troels

    2008-01-01

    was the most efficient in enhancing overall convertibility of the raw material to sugars and minimizing generation of furfural as a by-product. For scale-up of the process, high dry matter (DM) concentrations of 15-20% will be necessary. However, high DM hydrolysis and fermentation are limited by high...... and a low enzyme loading of 10 FPU/g cellulose in an industrial acceptable time frame of 96 h. Cellulose and hemicellulose conversion from enzymatic hydrolysis were 70 and 68%, respectively, and an overall ethanol yield from SSF was 68%....

  7. Production and characterization of enzymatic cocktail produced by Aspergillus niger using green macroalgae as nitrogen source and its application in the pre-treatment for biogas production from Ulva rigida.

    Science.gov (United States)

    Karray, Raida; Hamza, Manel; Sayadi, Sami

    2016-09-01

    Marine macroalgae are gaining more and more importance as a renewable feedstock for durable bioenergy production, but polysaccharides of this macroalgae are structurally complex in its chemical composition. The use of enzymatic hydrolysis may provide new pathways in the conversion of complex polysaccharides to fermentable sugars. In this study, an enzymatic cocktail with high specificity was first isolated from Aspergillus niger using the green macroalgae Ulva rigida as nitrogen source. The cocktail is rich on β-glucosidase, pectinase and carboxy-methyl-cellulase (CMCase). The highest activity was obtained with β-glucosidase (109IUmL(-1)) and pectinase (76IUmL(-1)), while CMCase present the lowest activity 4.6IUmL(-1). The U. rigida pre-treatment with this enzymatic cocktail showed high rate of reduced sugar release, and could bring promising prospects for enzymatic pre-treatment of the biogas production from U. rigida biomass which reached 1175mLgCODint(-1). Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Process evaluation of enzymatic hydrolysis with filtrate recycle for the production of high concentration sugars.

    Science.gov (United States)

    Xue, Ying; Rusli, Jannov; Chang, Hou-Min; Phillips, Richard; Jameel, Hasan

    2012-02-01

    Process simulation and lab trials were carried out to demonstrate and confirm the efficiency of the concept that recycling hydrolysate at low total solid enzymatic hydrolysis is one of the options to increase the sugar concentration without mixing problems. Higher sugar concentration can reduce the capital cost for fermentation and distillation because of smaller retention volume. Meanwhile, operation cost will also decrease for less operating volume and less energy required for distillation. With the computer simulation, time and efforts can be saved to achieve the steady state of recycling process, which is the scenario for industrial production. This paper, to the best of our knowledge, is the first paper discussing steady-state saccharification with recycling of the filtrate form enzymatic hydrolysis to increase sugar concentration. Recycled enzymes in the filtrate (15-30% of the original enzyme loading) resulted in 5-10% higher carbohydrate conversion compared to the case in which recycled enzymes were denatured. The recycled hydrolysate yielded 10% higher carbohydrate conversion compared to pure sugar simulated hydrolysate at the same enzyme loading, which indicated hydrolysis by-products could boost enzymatic hydrolysis. The high sugar concentration (pure sugar simulated) showed inhibition effect, since about 15% decrease in carbohydrate conversion was observed compared with the case with no sugar added. The overall effect of hydrolysate recycling at WinGEMS simulated steady-state conditions with 5% total solids was increasing the sugar concentration from 35 to 141 g/l, while the carbohydrate conversion was 2% higher for recycling at steady state (87%) compared with no recycling strategy (85%). Ten percent and 15% total solid processes were also evaluated in this study.

  9. The influence of conformational fluctuations on enzymatic activity: modelling the functional motion of β-secretase

    International Nuclear Information System (INIS)

    Neri, M; Cascella, M; Micheletti, C

    2005-01-01

    Considerable insight into the functional activity of proteins and enzymes can be obtained by studying the low energy conformational distortions that the biopolymer can sustain. We carry out the characterization of these large scale structural changes for a protein of considerable pharmaceutical interest, the human β-secretase. Starting from the crystallographic structure of the protein, we use the recently introduced β-Gaussian model to identify, with negligible computational expenditure, the most significant distortions occurring in thermal equilibrium and the associated timescales. The application of this strategy helps us to gain considerable insight into the putative functional movements and, furthermore, allows us to identify a handful of key regions in the protein which have an important mechanical influence on the enzymatic activity despite being spatially distant from the active site. The results obtained within the Gaussian model are validated through an extensive comparison against an all-atom molecular dynamics simulation

  10. Preparation and Enzymatic Degradation of Porous Crosslinked Polylactides of Biomass Origin

    Directory of Open Access Journals (Sweden)

    Yuya Kido

    2014-06-01

    Full Text Available To understand the enzymatic degradation behavior of crosslinked polylactide (PLA, the preparation and enzymatic degradation of both thermoplastic (linear and crosslinked PLAs that have pore structures with different dimensions were carried out. The porous structures of the linear PLA samples were of micro and nanoporous nature, and prepared by batch foaming with supercritical CO2 and compared with the porous structures of crosslinked PLA (Lait-X created by the salt leaching method. The surface and cross-sectional morphologies of the porous structures were investigated by using scanning electron microscopy. The morphological analysis of porous Lait-X showed a rapid loss of physical features within 120 h of exposure to proteinase-K enzymatic degradation at 37 °C. Due to the higher affinity for water, enhanced enzymatic activity as compared to the linear PLA porous structures in the micro and nanoporous range was observed.

  11. Computational study on a puzzle in the biosynthetic pathway of anthocyanin: Why is an enzymatic oxidation/ reduction process required for a simple tautomerization?

    Science.gov (United States)

    Sato, Hajime; Wang, Chao; Yamazaki, Mami; Saito, Kazuki; Uchiyama, Masanobu

    2018-01-01

    In the late stage of anthocyanin biosynthesis, dihydroflavonol reductase (DFR) and anthocyanidin synthase (ANS) mediate a formal tautomerization. However, such oxidation/reduction process requires high energy and appears to be unnecessary, as the oxidation state does not change during the transformation. Thus, a non-enzymatic pathway of tautomerization has also been proposed. To resolve the long-standing issue of whether this non-enzymatic pathway is the main contributor for the biosynthesis, we carried out density functional theory (DFT) calculations to examine this non-enzymatic pathway from dihydroflavonol to anthocyanidin. We show here that the activation barriers for the proposed non-enzymatic tautomerization are too high to enable the reaction to proceed under normal aqueous conditions in plants. The calculations also explain the experimentally observed requirement for acidic conditions during the final step of conversion of 2-flaven-3,4-diol to anthocyanidin; a thermodynamically and kinetically favorable concerted pathway can operate under these conditions.

  12. Polyphenol Content, Physicochemical Properties, Enzymatic Activity, Anthocyanin Profiles, and Antioxidant Capacity of Cerasus humilis (Bge. Sok. Genotypes

    Directory of Open Access Journals (Sweden)

    Suwen Liu

    2018-01-01

    Full Text Available Seven varieties of Chinese dwarf cherries were evaluated and compared with respect to their weight, diameter, titratable acidity, total soluble solids, color, polyphenol contents, ascorbic acid levels, anthocyanin profiles, enzymatic activity, and antioxidant capacity. The fruits are rich in phenolic content (339.07–770.30 mg/100 g fresh weight. Nine anthocyanins were obtained from fruits after chromatographic separation and their structures analyzed using HPLC-ESI-MS/MS. Cyanidin-3-glucoside was the major anthocyanin with 50.36–78.39% concentration. Three anthocyanins were reported for the first time in these cherries. They exhibit low polyphenol oxidase and peroxidase activities, but their superoxide dismutase activity is high (572.75–800.17 U/g FW. The highest amounts of soluble solid content (15.67 Brix %, total titratable acid (1.90%, ascorbic acid (18.47 mg/100 g FW, and total anthocyanin (152.66 mg/100 g FW were observed. Three methods (DPPH-scavenging ability, oxygen radical absorbance capacity assay, and cellular antioxidant activity assay were employed to evaluate the antioxidant capacity of the phenolic extracts of these cherries. Number 5 has the highest values of ORAC and CAA of 205.68 μmol TE/g DM and 99.67 μmol QE/100 g FW, respectively.

  13. Enzymatic biosensors based on the use of metal oxide nanoparticles

    International Nuclear Information System (INIS)

    Shi, Xinhao; Gu, Wei; Li, Bingyu; Chen, Ningning; Zhao, Kai; Xian, Yuezhong

    2014-01-01

    Over the past decades, various techniques have been developed to obtain materials at a nanoscale level to design biosensors with high sensitivity, selectivity and efficiency. Metal oxide nanoparticles (MONPs) are of particular interests and have received much attention because of their unique physical, chemical and catalytic properties. This review summarizes the progress made in enzymatic biosensors based on the use of MONPs. Synthetic methods, strategies for immobilization, and the functions of MONPs in enzymatic biosensing systems are reviewed and discussed. The article is subdivided into sections on enzymatic biosensors based on (a) zinc oxide nanoparticles, (b) titanium oxide nanoparticles, (c) iron oxide nanoparticles, and (d) other metal oxide nanoparticles. While substantial advances have been made in MONPs-based enzymatic biosensors, their applications to real samples still lie ahead because issues such as reproducibility and sensor stability have to be solved. (author)

  14. Ectomycorrhizal Fungal Communities and Enzymatic Activities Vary across an Ecotone between a Forest and Field.

    Science.gov (United States)

    Rúa, Megan A; Moore, Becky; Hergott, Nicole; Van, Lily; Jackson, Colin R; Hoeksema, Jason D

    2015-08-28

    Extracellular enzymes degrade macromolecules into soluble substrates and are important for nutrient cycling in soils, where microorganisms, such as ectomycorrhizal (ECM) fungi, produce these enzymes to obtain nutrients. Ecotones between forests and fields represent intriguing arenas for examining the effect of the environment on ECM community structure and enzyme activity because tree maturity, ECM composition, and environmental variables may all be changing simultaneously. We studied the composition and enzymatic activity of ECM associated with loblolly pine (Pinus taeda) across an ecotone between a forest where P. taeda is established and an old field where P. taeda saplings had been growing for <5 years. ECM community and environmental characteristics influenced enzyme activity in the field, indicating that controls on enzyme activity may be intricately linked to the ECM community, but this was not true in the forest. Members of the Russulaceae were associated with increased phenol oxidase activity and decreased peroxidase activity in the field. Members of the Atheliaceae were particularly susceptible to changes in their abiotic environment, but this did not mediate differences in enzyme activity. These results emphasize the complex nature of factors that dictate the distribution of ECM and activity of their enzymes across a habitat boundary.

  15. Catabolite regulation of enzymatic activities in a white pox pathogen and commensal bacteria during growth on mucus polymers from the coral Acropora palmata.

    Science.gov (United States)

    Krediet, Cory J; Ritchie, Kim B; Teplitski, Max

    2009-11-16

    Colonization of host mucus surfaces is one of the first steps in the establishment of coral-associated microbial communities. Coral mucus contains a sulfated glycoprotein (in which oligosaccharide decorations are connected to the polypeptide backbone by a mannose residue) and molecules that result from its degradation. Mucus is utilized as a growth substrate by commensal and pathogenic organisms. Two representative coral commensals, Photobacterium mandapamensis and Halomonas meridiana, differed from a white pox pathogen Serratia marcescens PDL100 in the pattern with which they utilized mucus polymers of Acropora palmata. Incubation with the mucus polymer increased mannopyranosidase activity in S. marcescens, suggestive of its ability to cleave off oligosaccharide side chains. With the exception of glucosidase and N-acetyl galactosaminidase, glycosidases in S. marcescens were subject to catabolite regulation by galactose, glucose, arabinose, mannose and N-acetyl-glucosamine. In commensal P. mandapamensis, at least 10 glycosidases were modestly induced during incubation on coral mucus. Galactose, arabinose, mannose, but not glucose or N-acetyl-glucosamine had a repressive effect on glycosidases in P. mandapamensis. Incubation with the mucus polymers upregulated 3 enzymatic activities in H. meridiana; glucose and galactose appear to be the preferred carbon source in this bacterium. Although all these bacteria were capable of producing the same glycosidases, the differences in the preferred carbon sources and patterns of enzymatic activities induced during growth on the mucus polymer in the presence of these carbon sources suggest that to establish themselves within the coral mucus surface layer commensals and pathogens rely on different enzymatic activities.

  16. Enzymatic saccharification of brown seaweed for production of fermentable sugars.

    Science.gov (United States)

    Sharma, Sandeep; Horn, Svein Jarle

    2016-08-01

    This study shows that high drying temperatures negatively affect the enzymatic saccharification yield of the brown seaweed Saccharina latissima. The optimal drying temperature of the seaweed in terms of enzymatic sugar release was found to be 30°C. The enzymatic saccharification process was optimized by investigating factors such as kinetics of sugar release, enzyme dose, solid loading and different blend ratios of cellulases and an alginate lyase. It was found that the seaweed biomass could be efficiently hydrolysed to fermentable sugars using a commercial cellulase cocktail. The inclusion of a mono-component alginate lyase was shown to improve the performance of the enzyme blend, in particular at high solid loadings. At 25% dry matter loading a combined glucose and mannitol concentration of 74g/L was achieved. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Highly active engineered-enzyme oriented monolayers: formation, characterization and sensing applications

    Directory of Open Access Journals (Sweden)

    Patolsky Fernando

    2011-06-01

    presented here, with the resulting high enzymatic activity, has never been reported. There are many potential applications for selective localization of active proteins at patterned surfaces, for example, bioMEMS (MEMS - Micro-Electro-Mechanical Systems. Due to the success of the method, presented here, it was decided to continue a research project of a biosensor by transferring it to a high aspect ratio platform - nanotubes.

  18. Improving enzymatic activities and thermostability of a tri-functional enzyme with SOD, catalase and cell-permeable activities.

    Science.gov (United States)

    Luangwattananun, Piriya; Eiamphungporn, Warawan; Songtawee, Napat; Bülow, Leif; Isarankura Na Ayudhya, Chartchalerm; Prachayasittikul, Virapong; Yainoy, Sakda

    2017-04-10

    Synergistic action of major antioxidant enzymes, e.g., superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) is known to be more effective than the action of any single enzyme. Recently, we have engineered a tri-functional enzyme, 6His-MnSOD-TAT/CAT-MnSOD (M-TAT/CM), with SOD, CAT and cell-permeable activities. The protein actively internalized into the cells and showed superior protection against oxidative stress-induced cell death over native enzymes fused with TAT. To improve its molecular size, enzymatic activity and stability, in this study, MnSOD portions of the engineered protein were replaced by CuZnSOD, which is the smallest and the most heat resistant SOD isoform. The newly engineered protein, CAT-CuZnSOD/6His-CuZnSOD-TAT (CS/S-TAT), had a 42% reduction in molecular size and an increase in SOD and CAT activities by 22% and 99%, respectively. After incubation at 70°C for 10min, the CS/S-TAT retained residual SOD activity up to 54% while SOD activity of the M-TAT/CM was completely abolished. Moreover, the protein exhibited a 5-fold improvement in half-life at 70°C. Thus, this work provides insights into the design and synthesis of a smaller but much more stable multifunctional antioxidant enzyme with ability to enter mammalian cells for further application as protective/therapeutic agent against oxidative stress-related conditions. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Coated tube for immunochemical and enzymatic assays

    International Nuclear Information System (INIS)

    Brown, J.L.; Lin, W.H.-T.; Woods, J.W.

    1979-01-01

    Containers such as test tubes suitable for use in solid phase immunochemical, enzymatical and particularly radioimmunoassay procedures are described. The lower part of the tube is a polymer, coated with an inert protein to which a biologically active substance eg an antibody to triiodothyronine, thyroxine or digoxin, is attached. (U.K.)

  20. Effect of the exposure to suspended solids on the enzymatic activity in the bivalve Sinonovacula constricta

    Directory of Open Access Journals (Sweden)

    Guojun Yang

    2017-01-01

    Full Text Available Aquatic animals are susceptible to sudden changes of their living environment but they adopt strategies to cope with adverse environmental challenges. Contamination by suspended solids, often associated with a dramatic change in the concentrations of important water-quality variables is a frequent occurrence in China's coastal waters and estuaries. Here we studied the impact of suspended solids on the activities of the antioxidant enzymes superoxide dismutase (SOD and catalase (CAT, as well as adenosine triphosphates (including Na+ K+-ATPase, Mg+ +-ATPase, Ca+ +-ATPase and H+ K+-ATPase in the gills and visceral mass tissues of the molluscan bivalve Sinonovacula constricta exposed (4, 8, 12, 16, 20, and 24 days to various concentrations of suspended solids. Our results showed that the antioxidant enzymes cooperated closely to effectively scavenge superoxide anion free radicals and H2O2 (which can ultimately inhibit gill activity through the modification of SOD and/or CAT enzymatic activities. ATPases activity (considered to be a sensitive indicator of toxicity could play an effective role in the maintenance of functional integrity of the plasma membranes as well as some other intracellular functions. After the exposure, a decrease in the Na+ K+-ATPase, Mg+ +-ATPase, and Ca+ +-ATPase activity of the gills was observed suggesting that they were inhibited by the treatments. These results also indicated that, from day 4 to day 16, exposure to high concentrations of suspended solids had an inhibitory effect on the activity of H+-K+-ATPase in the visceral mass of S. constricta. However, after a period of adaptation the H+-K+-ATPase activity was restored to original levels. Our results suggest that long-term exposure to high levels of suspended solids disturb osmoregulation, gastric acid secretion and digestion, cause oxidative damage, as a consequence of antioxidant enzymes inactivation which eventually damages the gills, affect the food intake

  1. Isolation and purification of arctigenin from Fructus Arctii by enzymatic hydrolysis combined with high-speed counter-current chromatography.

    Science.gov (United States)

    Liu, Feng; Xi, Xingjun; Wang, Mei; Fan, Li; Geng, Yanling; Wang, Xiao

    2014-02-01

    Enzymatic hydrolysis pretreatment combined with high-speed counter-current chromatography for the transformation and isolation of arctigenin from Fructus Arctii was successfully developed. In the first step, the extract solution of Fructus Arctii was enzymatic hydrolyzed by β-glucosidase. The optimal hydrolysis conditions were 40°C, pH 5.0, 24 h of hydrolysis time, and 1.25 mg/mL β-glucosidase concentration. Under these conditions, the content of arctigenin was transformed from 2.60 to 12.59 mg/g. In the second step, arctigenin in the hydrolysis products was separated and purified by high-speed counter-current chromatography with a two-phase solvent system composed of petroleum ether/ethyl acetate/methanol/water (10:25:15:20, v/v), and the fraction was analyzed by HPLC, ESI-MS, and (1)H NMR spectroscopy. Finally, 102 mg of arctigenin with a purity of 98.9% was obtained in a one-step separation from 200 mg of hydrolyzed sample. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Effect of enzymatic treatment of extracted sunflower proteins on solubility, amino acid composition, and surface activity.

    Science.gov (United States)

    Conde, José Miñones; Escobar, María del Mar Yust; Pedroche Jiménez, Justo J; Rodríguez, Francisco Millán; Rodríguez Patino, Juan M

    2005-10-05

    Industrial proteins from agriculture of either animal or vegetable origin, including their peptide derivatives, are of great importance, from the qualitative and quantitative point of view, in food formulations (emulsions and foams). A fundamental understanding of the physical, chemical, and functional properties of these proteins is essential if the performance of proteins in foods is to be improved and if underutilized proteins, such as plant proteins (and their hydrolysates and peptides derivatives), are to be increasingly used in traditional and new processed food products (safe, high-quality, health foods with good nutritional value). In this contribution we have determined the main physicochemical characteristics (solubility, composition, and analysis of amino acids) of a sunflower protein isolate (SPI) and its hydrolysates with low (5.62%), medium (23.5%), and high (46.3%) degrees of hydrolysis. The hydrolysates were obtained by enzymatic treatment with Alcalase 2.4 L for DH 5.62 and 23.5% and with Alcalase 2.4 L and Flavorzyme 1000 MG sequentially for DH 46.3%. The protein concentration dependence on surface pressure (surface pressure isotherm), a measure of the surface activity of the products (SPI and its hydrolysates), was obtained by tensiometry. We have observed that the degree of hydrolysis has an effect on solubility, composition, and content of the amino acids of the SPI and its hydrolysates. The superficial activity and the adsorption efficiency were also affected by the degree of hydrolysis.

  3. Enhancing bioactive peptide release and identification using targeted enzymatic hydrolysis of milk proteins.

    Science.gov (United States)

    Nongonierma, Alice B; FitzGerald, Richard J

    2018-06-01

    Milk proteins have been extensively studied for their ability to yield a range of bioactive peptides following enzymatic hydrolysis/digestion. However, many hurdles still exist regarding the widespread utilization of milk protein-derived bioactive peptides as health enhancing agents for humans. These mostly arise from the fact that most milk protein-derived bioactive peptides are not highly potent. In addition, they may be degraded during gastrointestinal digestion and/or have a low intestinal permeability. The targeted release of bioactive peptides during the enzymatic hydrolysis of milk proteins may allow the generation of particularly potent bioactive hydrolysates and peptides. Therefore, the development of milk protein hydrolysates capable of improving human health requires, in the first instance, optimized targeted release of specific bioactive peptides. The targeted hydrolysis of milk proteins has been aided by a range of in silico tools. These include peptide cutters and predictive modeling linking bioactivity to peptide structure [i.e., molecular docking, quantitative structure activity relationship (QSAR)], or hydrolysis parameters [design of experiments (DOE)]. Different targeted enzymatic release strategies employed during the generation of milk protein hydrolysates are reviewed herein and their limitations are outlined. In addition, specific examples are provided to demonstrate how in silico tools may help in the identification and discovery of potent milk protein-derived peptides. It is anticipated that the development of novel strategies employing a range of in silico tools may help in the generation of milk protein hydrolysates containing potent and bioavailable peptides, which in turn may be used to validate their health promoting effects in humans. Graphical abstract The targeted enzymatic hydrolysis of milk proteins may allow the generation of highly potent and bioavailable bioactive peptides.

  4. Enzymatic- and temperature-sensitive controlled release of ultrasmall superparamagnetic iron oxides (USPIOs

    Directory of Open Access Journals (Sweden)

    Ortega Ryan A

    2011-02-01

    Full Text Available Abstract Background Drug and contrast agent delivery systems that achieve controlled release in the presence of enzymatic activity are becoming increasingly important, as enzymatic activity is a hallmark of a wide array of diseases, including cancer and atherosclerosis. Here, we have synthesized clusters of ultrasmall superparamagnetic iron oxides (USPIOs that sense enzymatic activity for applications in magnetic resonance imaging (MRI. To achieve this goal, we utilize amphiphilic poly(propylene sulfide-bl-poly(ethylene glycol (PPS-b-PEG copolymers, which are known to have excellent properties for smart delivery of drug and siRNA. Results Monodisperse PPS polymers were synthesized by anionic ring opening polymerization of propylene sulfide, and were sequentially reacted with commercially available heterobifunctional PEG reagents and then ssDNA sequences to fashion biofunctional PPS-bl-PEG copolymers. They were then combined with hydrophobic 12 nm USPIO cores in the thin-film hydration method to produce ssDNA-displaying USPIO micelles. Micelle populations displaying complementary ssDNA sequences were mixed to induce crosslinking of the USPIO micelles. By design, these crosslinking sequences contained an EcoRV cleavage site. Treatment of the clusters with EcoRV results in a loss of R2 negative contrast in the system. Further, the USPIO clusters demonstrate temperature sensitivity as evidenced by their reversible dispersion at ~75°C and re-clustering following return to room temperature. Conclusions This work demonstrates proof of concept of an enzymatically-actuatable and thermoresponsive system for dynamic biosensing applications. The platform exhibits controlled release of nanoparticles leading to changes in magnetic relaxation, enabling detection of enzymatic activity. Further, the presented functionalization scheme extends the scope of potential applications for PPS-b-PEG. Combined with previous findings using this polymer platform that

  5. Enzymatic- and temperature-sensitive controlled release of ultrasmall superparamagnetic iron oxides (USPIOs).

    Science.gov (United States)

    Yu, Shann S; Scherer, Randy L; Ortega, Ryan A; Bell, Charleson S; O'Neil, Conlin P; Hubbell, Jeffrey A; Giorgio, Todd D

    2011-02-27

    Drug and contrast agent delivery systems that achieve controlled release in the presence of enzymatic activity are becoming increasingly important, as enzymatic activity is a hallmark of a wide array of diseases, including cancer and atherosclerosis. Here, we have synthesized clusters of ultrasmall superparamagnetic iron oxides (USPIOs) that sense enzymatic activity for applications in magnetic resonance imaging (MRI). To achieve this goal, we utilize amphiphilic poly(propylene sulfide)-bl-poly(ethylene glycol) (PPS-b-PEG) copolymers, which are known to have excellent properties for smart delivery of drug and siRNA. Monodisperse PPS polymers were synthesized by anionic ring opening polymerization of propylene sulfide, and were sequentially reacted with commercially available heterobifunctional PEG reagents and then ssDNA sequences to fashion biofunctional PPS-bl-PEG copolymers. They were then combined with hydrophobic 12 nm USPIO cores in the thin-film hydration method to produce ssDNA-displaying USPIO micelles. Micelle populations displaying complementary ssDNA sequences were mixed to induce crosslinking of the USPIO micelles. By design, these crosslinking sequences contained an EcoRV cleavage site. Treatment of the clusters with EcoRV results in a loss of R2 negative contrast in the system. Further, the USPIO clusters demonstrate temperature sensitivity as evidenced by their reversible dispersion at ~75°C and re-clustering following return to room temperature. This work demonstrates proof of concept of an enzymatically-actuatable and thermoresponsive system for dynamic biosensing applications. The platform exhibits controlled release of nanoparticles leading to changes in magnetic relaxation, enabling detection of enzymatic activity. Further, the presented functionalization scheme extends the scope of potential applications for PPS-b-PEG. Combined with previous findings using this polymer platform that demonstrate controlled drug release in oxidative

  6. Moving towards a Competitive Fully Enzymatic Biodiesel Process

    Directory of Open Access Journals (Sweden)

    Silvia Cesarini

    2015-06-01

    Full Text Available Enzymatic biodiesel synthesis can solve several problems posed by the alkaline-catalyzed transesterification but it has the drawback of being too expensive to be considered competitive. Costs can be reduced by lipase improvement, use of unrefined oils, evaluation of soluble/immobilized lipase preparations, and by combination of phospholipases with a soluble lipase for biodiesel production in a single step. As shown here, convenient natural tools have been developed that allow synthesis of high quality FAMEs (EN14214 from unrefined oils in a completely enzymatic single-step process, making it fully competitive.

  7. Recent Advances in Enzymatic Fuel Cells: Experiments and Modeling

    Directory of Open Access Journals (Sweden)

    Ivan Ivanov

    2010-04-01

    Full Text Available Enzymatic fuel cells convert the chemical energy of biofuels into electrical energy. Unlike traditional fuel cell types, which are mainly based on metal catalysts, the enzymatic fuel cells employ enzymes as catalysts. This fuel cell type can be used as an implantable power source for a variety of medical devices used in modern medicine to administer drugs, treat ailments and monitor bodily functions. Some advantages in comparison to conventional fuel cells include a simple fuel cell design and lower cost of the main fuel cell components, however they suffer from severe kinetic limitations mainly due to inefficiency in electron transfer between the enzyme and the electrode surface. In this review article, the major research activities concerned with the enzymatic fuel cells (anode and cathode development, system design, modeling by highlighting the current problems (low cell voltage, low current density, stability will be presented.

  8. Ultrasonic-assisted enzymatic extraction of phenolics from broccoli (Brassica oleracea L. var. italica) inflorescences and evaluation of antioxidant activity in vitro.

    Science.gov (United States)

    Wu, Hao; Zhu, Junxiang; Yang, Long; Wang, Ran; Wang, Chengrong

    2015-06-01

    An efficient ultrasonic-assisted enzymatic extraction technique was applied to extracting phenolics from broccoli inflorescences without organic solvents. The synergistic model of enzymolysis and ultrasonication simultaneously was selected, and the enzyme combination was optimized by orthogonal test: cellulase 7.5 mg/g FW (fresh weight), pectinase 10 mg/g FW, and papain 1.0 mg/g FW. The operating parameters in ultrasonic-assisted enzymatic extraction were optimized with response surface methodology using Box-Behnken design. The optimal extraction conditions were as follows: ultrasonic power, 440 W; liquid to material ratio, 7.0:1 mL/g; pH value of 6.0 at 54.5 ℃ for 10 min. Under these conditions, the extraction yield of phenolics achieved 1.816 ± 0.0187 mg gallic acid equivalents/gram FW. The free radical scavenging activity of ultrasonic-assisted enzymatic extraction extracts was determined by 1,1-diphenyl-2-picrylhydrazyl·assay with EC50 values of 0.25, and total antioxidant activity was determined by ferric reducing antioxidant power assay with ferric reducing antioxidant power value of 0.998 mmol FeSO4/g compared with the referential ascorbic acid of 1.184 mmol FeSO4/g. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  9. An enzymatic method for the determination of fructans in foods and food products - Comparison of the results by high performance anion exchange chromatography with pulsed amperemetric detection

    DEFF Research Database (Denmark)

    Andersen, Rikke; Sørensen, A.

    1999-01-01

    We report a new and non-equipment demanding method of measuring the content of fructans as well as the contents of free glucose, free fructose and sucrose in foods and food products enzymatically. This method comprises hydrolysis of fructans into D-glucose and D-fructose enzymatically...... effects than the fructanase reported as normally used. The method is tested on ten standard substances and five fructan products, and nine foods and food products are also analysed. The enzymatic measurement of the released sugars is confirmed by measurements done by high performance anion exchange...

  10. Application of high hydrostatic pressure for increasing activity and stability of enzymes.

    Science.gov (United States)

    Mozhaev, V V; Lange, R; Kudryashova, E V; Balny, C

    1996-10-20

    Elevated hydrostatic pressure has been used to increase catalytic activity and thermal stability of alpha-chymotrypsin (CT). For an anilide substrate, characterized by a negative value of the reaction activation volume (DeltaV( not equal)), an increase in pressure at 20 degrees C results in an exponential acceleration of the hydrolysis rate catalyzed by CT reaching a 6.5-fold increase in activity at 4700 atm (4.7 kbar). Due to a strong temperature dependence of DeltaV( not equal), the acceleration effect of high pressure becomes more pronounced at high temperatures. For example, at 50 degrees C, under a pressure of 3.6 kbar, CT shows activity which is more than 30 times higher than the activity at normal conditions (20 degrees C, 1 atm). At pressures of higher than 3.6 kbar, the enzymatic activity is decreased due to a pressure-induced denaturation.Elevated hydrostatic pressure is also efficient for increasing stability of CT against thermal denaturation. For example, at 55 degrees C, CT is almost instantaneously inactivated at atmospheric pressure, whereas under a pressure of 1.8 kbar CT retains its anilide-hydrolyzing activity during several dozen minutes. Additional stabilization can be achieved in the presence of glycerol, which is most effective for protection of CT at an intermediate concentration of 40% (v/v). There has been observed an additivity in stabilization effects of high pressure and glycerol: thermal inactivation of pressure-stabilized CT can be decelerated in a supplementary manner by addition of 40% (v/v) glycerol. The protection effect of glycerol on the catalytic activity and stability of CT becomes especially pronounced when both extreme factors of temperature and pressure reach critical values. For example, at approximately 55 degrees C and 4.7 kbar, enzymatic activity of CT in the presence of 40% (v/v) glycerol is severalfold higher than in aqueous buffer.The results of this study are discussed in terms of the hypotheses which explain the

  11. Effect of Different Calcium Sources Application on Antioxidant, Enzymatic Activity and Qualitative Characteristics of Apple (Malus domestic)

    OpenAIRE

    MirHassan Rasouli-Sadaghiani; Mohammad Moghaddas Gerani; Sanaz Ashrafi Saeidlou; Ebrahim Sepehr

    2017-01-01

    In order to determine the effect of different Ca sources, in improving enzymatic activity and some qualitative properties of red apple (Malusdomestica) an experiment was carried out in a completely randomized design. Apple trees were sprayed 5 times with CaCl2, CaO, Ca-EDTA and Ca(NO3)2 salts with an interval of 20 days from late June until early October. After harvesting fruits were kept in cold storage at standard condition for 150 days. Nitrogen, phosphorus, potassium, calcium, magnesium, ...

  12. Optimizing the Isolation of Microfibrillated Bamboo in High Pressure Enzymatic Hydrolysis

    Directory of Open Access Journals (Sweden)

    N. A. Sri Aprilia

    2015-07-01

    Full Text Available Bleached bamboo fiber was treated with a high pressure enzymatic hydrolysis (HPEH process in order to produce microfibrillated bamboo fiber (MBF. Mixture design of experiments was utilized to determine the optimal constituents of fiber, enzymes, and water for the HPEH process on the isolation yield of the MBF. Results showed the optimal combination for the maximal yield isolation of the MBF was 1 g fiber, 1 g enzyme, and 1 L water at 90 MPa and 70 °C. The influence of the reaction time of the HPEH process (6 to 48 h was also evaluated in this study. Morphological and thermal property analyses of untreated and treated bamboo fibers revealed that the HPEH process was effective for removing non-cellulosic components from the fibers. Thus, the HPEH process is an effective method for the isolation of the MBF, with the benefits of elevated crystallinity and thermal stability.

  13. Enzymatic hydrolsis of pretreated rice straw

    Energy Technology Data Exchange (ETDEWEB)

    Vlasenko, E.Y.; Shoemaker, S.P. [California Inst. of Food and Agricultural Research, Davis, CA (United States); Ding, H. [California Univ., Davis (Canada). Dept. of Food Science and Technology; Labavitch, J.M. [California Univ., Davis, CA (United States). Dept. of Pomology

    1997-02-01

    California rice straw is being evaluated as a feedstock for production of power and fuel. This paper examines the initial steps in the process: pretreatment of rice straw and enzymatic hydrolysis of the polysaccharides in the pretreated material to soluble sugars. Rice straw was subjected to three distinct pretreatment procedures: acid-catalyzed steam explosion (Swan Biomass Company), acid hydrolysis (U.S. DOE National Renewable Energy Laboratory), and ammonia fiber explosion or AFEX (Texas A and M University). Standard conditions for each pretreatment were used, but none was optimized for rice straw specifically. Six commercial cellulases, products of Genencor International (USA), Novo (Denmark), Iogen (Canada) and Fermtech (Russia) were used for hydrolysis. The Swan- and the acid-pretreatments effectively removed hemicellulose from rice straw, providing high yields of fermentable sugars. The AFEX-pretreatment was distinctly different from other pretreatments in that it did not significantly solubilize hemicellulose. All three pretreatment procedures substantially increased enzymatic digestibility of rice straw. Three commercial Trichoderma-reesei-derived enzyme preparations: Cellulase 100L (Iogen), Spezyme CP (Genencor), and Al (Fermtech), were more active on pretreated rice straw compared than others tested. Conditions for hydrolysis of rice straw using Cellulase 100L were evaluated. The supplementation of this enzyme preparation with cellobiase (Novozyme 188) significantly improved the parameters of hydrolysis for the Swan- and the acid-pretreated materials, but did not affect the hydrolysis of the AFEX-pretreated rice straw. (Author)

  14. Understanding the effects of lignosulfonate on enzymatic saccharification of pure cellulose

    Science.gov (United States)

    Hongming Lou; Haifeng Zhou; Xiuli Li; Mengxia Wang; J.Y. Zhu; Xueqing Qiu

    2014-01-01

    The effects of lignosulfonate (LS) on enzymatic saccharification of pure cellulose were studied. Four fractions of LS with different molecular weight (MW) prepared by ultrafiltration of a commercial LS were applied at different loadings to enzymatic hydrolysis of Whatman paper under different pH. Using LS fractions with low MW and high degree of sulfonation can enhance...

  15. Mutation of Asn28 Disrupts the Dimerization and Enzymatic Activity of SARS 3CL

    Energy Technology Data Exchange (ETDEWEB)

    Barrila, J.; Gabelli, S; Bacha, U; Amzel, M; Freire, E

    2010-01-01

    Coronaviruses are responsible for a significant proportion of annual respiratory and enteric infections in humans and other mammals. The most prominent of these viruses is the severe acute respiratory syndrome coronavirus (SARS-CoV) which causes acute respiratory and gastrointestinal infection in humans. The coronavirus main protease, 3CL{sup pro}, is a key target for broad-spectrum antiviral development because of its critical role in viral maturation and high degree of structural conservation among coronaviruses. Dimerization is an indispensable requirement for the function of SARS 3CL{sup pro} and is regulated through mechanisms involving both direct and long-range interactions in the enzyme. While many of the binding interactions at the dimerization interface have been extensively studied, those that are important for long-range control are not well-understood. Characterization of these dimerization mechanisms is important for the structure-based design of new treatments targeting coronavirus-based infections. Here we report that Asn28, a residue 11 {angstrom} from the closest residue in the opposing monomer, is essential for the enzymatic activity and dimerization of SARS 3CLpro. Mutation of this residue to alanine almost completely inactivates the enzyme and results in a 19.2-fold decrease in the dimerization K{sub d}. The crystallographic structure of the N28A mutant determined at 2.35 {angstrom} resolution reveals the critical role of Asn28 in maintaining the structural integrity of the active site and in orienting key residues involved in binding at the dimer interface and substrate catalysis. These findings provide deeper insight into complex mechanisms regulating the activity and dimerization of SARS 3CL{sup pro}.

  16. Enzyme-immobilized SiO2-Si electrode: Fast interfacial electron transfer with preserved enzymatic activity

    Science.gov (United States)

    Wang, Gang; Yau, Siu-Tung

    2005-12-01

    The enzyme, glucose oxidase (GOx), is immobilized using electrostatic interaction on the native oxide of heavily doped n-type silicon. Voltammetric measurement shows that the immobilized GOx gives rise to a very fast enzyme-silicon interfacial electron transfer rate constant of 7.9s-1. The measurement also suggests that the enzyme retains its native conformation when immobilized on the silicon surface. The preserved native conformation of GOx is further confirmed by testing the enzymatic activity of the immobilized GOx using glucose. The GOx-immobilized silicon is shown to behave as a glucose sensor that detects glucose with concentrations as low as 50μM.

  17. Investigation of bi-enzymatic reactor based on hybrid monolith with nanoparticles embedded and its proteolytic characteristics.

    Science.gov (United States)

    Shangguan, Lulu; Zhang, Lingyi; Xiong, Zhichao; Ren, Jun; Zhang, Runsheng; Gao, Fangyuan; Zhang, Weibing

    2015-04-03

    The bottom-up strategy of proteomic profiling study based on mass spectrometer (MS) has drawn high attention. However, conventional solution-based digestion could not satisfy the demands of highly efficient and complete high throughput proteolysis of complex samples. We proposed a novel bi-enzymatic reactor by immobilizing two different enzymes (trypsin/chymotrypsin) onto a mixed support of hybrid organic-inorganic monolith with SBA-15 nanoparticles embedded. Typsin and chymotrypsin were crossly immobilized onto the mixed support by covalent bonding onto the monolith with glutaraldehyde as bridge reagent and chelation via copper ion onto the nanoparticles, respectively. Compared with single enzymatic reactors, the bi-enzymatic reactor improved the overall functional analysis of membrane proteins of rat liver by doubling the number of identified peptides (from 1184/1010 with trypsin/chymotrypsin enzymatic reactors to 2891 with bi-enzymatic reactor), which led to more proteins identified with deep coverage (from 452/336 to 620); the efficiency of the bi-enzymatic reactor is also better than that of solution-based tandem digestion, greatly shorting the digestion time from 24h to 50s. Moreover, more transmembrane proteins were identified by bi-enzymatic reactor (106) compared with solution-based tandem digestion (95) with the same two enzymes and enzymatic reactors with single enzyme immobilized (75 with trypsin and 66 with chymotrypsin). The proteolytic characteristics of the bi-enzymatic reactors were evaluated by applying them to digestion of rat liver proteins. The reactors showed good digestion capability for proteins with different hydrophobicity and molecular weight. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Starch: chemistry, microstructure, processing and enzymatic degradation

    Science.gov (United States)

    Starch is recognized as one of the most abundant and important commodities containing value added attributes for a vast number of industrial applications. Its chemistry, structure, property and susceptibility to various chemical, physical and enzymatic modifications offer a high technological value ...

  19. Interrogating the activities of conformational deformed enzyme by single-molecule fluorescence-magnetic tweezers microscopy

    Science.gov (United States)

    Guo, Qing; He, Yufan; Lu, H. Peter

    2015-01-01

    Characterizing the impact of fluctuating enzyme conformation on enzymatic activity is critical in understanding the structure–function relationship and enzymatic reaction dynamics. Different from studying enzyme conformations under a denaturing condition, it is highly informative to manipulate the conformation of an enzyme under an enzymatic reaction condition while monitoring the real-time enzymatic activity changes simultaneously. By perturbing conformation of horseradish peroxidase (HRP) molecules using our home-developed single-molecule total internal reflection magnetic tweezers, we successfully manipulated the enzymatic conformation and probed the enzymatic activity changes of HRP in a catalyzed H2O2–amplex red reaction. We also observed a significant tolerance of the enzyme activity to the enzyme conformational perturbation. Our results provide a further understanding of the relation between enzyme behavior and enzymatic conformational fluctuation, enzyme–substrate interactions, enzyme–substrate active complex formation, and protein folding–binding interactions. PMID:26512103

  20. Enzymatic production of dietary nucleotides from low-soluble purine bases by an efficient, thermostable and alkali-tolerant biocatalyst.

    Science.gov (United States)

    Del Arco, J; Cejudo-Sanches, J; Esteban, I; Clemente-Suárez, V J; Hormigo, D; Perona, A; Fernández-Lucas, J

    2017-12-15

    Traditionally, enzymatic synthesis of nucleoside-5'-monophosphates (5'-NMPs) using low water-soluble purine bases has been described as less efficient due to their low solubility in aqueous media. The use of enzymes from extremophiles, such as thermophiles or alkaliphiles, offers the potential to increase solubilisation of these bases by employing high temperatures or alkaline pH. This study describes the cloning, expression and purification of hypoxanthine-guanine-xanthine phosphoribosyltransferase from Thermus thermophilus (TtHGXPRT). Biochemical characterization indicates TtHGXPRT as a homotetramer with excellent activity and stability across a broad range of temperatures (50-90°C) and ionic strengths (0-500mMNaCl), but it also reveals an unusually high activity and stability under alkaline conditions (pH range 8-11). In order to explore the potential of TtHGXPRT as an industrial biocatalyst, enzymatic production of several dietary 5'-NMPs, such as 5'-GMP and 5'-IMP, was carried out at high concentrations of guanine and hypoxanthine. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Enzymatic Synthesis and Anti-Allergic Activities of Curcumin Oligosaccharides

    Directory of Open Access Journals (Sweden)

    Kei Shimoda

    2010-01-01

    Full Text Available Curcumin 4‘- O -glucooligosaccharides were synthesized by a two step-enzymatic method using almond β-glucosidase and cyclodextrin glucanotransferase (CGTase. Curcumin was glucosylated to curcumin 4‘- O -β-D-glucopyranoside by almond β-glucosidase in 19% yield. Curcumin 4‘- O -β-D-glucopyranoside was converted into curcumin 4‘- O -β-glucooligosaccharides, i.e. 4‘- O -β-maltoside (51% and 4‘- O -β-maltotrioside (25%, by further CGTase-catalyzed glycosylation. Curcumin 4‘- O -β-glycosides showed suppressive action on IgE antibody formation and inhibitory effects on histamine release from rat peritoneal mast cells.

  2. Enzymatic synthesis of C-11 formaldehyde: concise communication

    International Nuclear Information System (INIS)

    Slegers, G.; Lambrecht, R.H.D.; Vandewalle, T.; Meulewaeter, L.; Vandecasteele, C.

    1984-01-01

    An enzymatic synthesis of C-11 formaldehyde from C-11 methanol is presented, with immobilized alcohol oxidase and catalase: a rapid, simple procedure, with a high and reproducible yield. Carbon-11 methanol is oxidized to C-11 formaldehyde by passage over a column on which the enzymes alcohol oxidase and catalase are immobilized. The catalase increases reaction velocity by recycling the oxygen, and prevents destruction of the alcohol oxidase by eliminating the excess of hydrogen peroxide. The yield of the enzyme-catalyzed oxidation was 80-95%. A specific activity of 400-450 mCi/μmole was obtained at EOB + 20 min. Various immobilization techniques and the optimal reaction conditions of the immobilized enzymes are investigated

  3. Enzymatic synthesis of dimeric glycomimetic ligands of NK cell activation receptors

    Czech Academy of Sciences Publication Activity Database

    Drozdová, Anna; Bojarová, Pavla; Křenek, Karel; Weignerová, Lenka; Hensen, B.; Elling, L.; Christensen, H.; Jensen, H.H.; Pelantová, Helena; Kuzma, Marek; Bezouška, Karel; Krupová, Monika; Adámek, David; Slámová, Kristýna; Křen, Vladimír

    2011-01-01

    Roč. 346, č. 12 (2011), s. 1599-1609 ISSN 0008-6215 R&D Projects: GA ČR GP203/09/P024; GA ČR GD305/09/H008; GA ČR GA303/09/0477 Institutional research plan: CEZ:AV0Z50200510 Keywords : beta-N-Acetylhexosaminidase * alactosyltransferase * Enzymatic glycosylation Subject RIV: CE - Biochemistry Impact factor: 2.332, year: 2011

  4. Continuous enzymatic hydrolysis of lignocellulosic biomass with simultaneous detoxification and enzyme recovery.

    Science.gov (United States)

    Gurram, Raghu N; Menkhaus, Todd J

    2014-07-01

    Recovering hydrolysis enzymes and/or alternative enzyme addition strategies are two potential mechanisms for reducing the cost during the biochemical conversion of lignocellulosic materials into renewable biofuels and biochemicals. Here, we show that enzymatic hydrolysis of acid-pretreated pine wood with continuous and/or fed-batch enzyme addition improved sugar conversion efficiencies by over sixfold. In addition, specific activity of the hydrolysis enzymes (cellulases, hemicellulases, etc.) increased as a result of continuously washing the residual solids with removal of glucose (avoiding the end product inhibition) and other enzymatic inhibitory compounds (e.g., furfural, hydroxymethyl furfural, organic acids, and phenolics). As part of the continuous hydrolysis, anion exchange resin was tested for its dual application of simultaneous enzyme recovery and removal of potential enzymatic and fermentation inhibitors. Amberlite IRA-96 showed favorable adsorption profiles of inhibitors, especially furfural, hydroxymethyl furfural, and acetic acid with low affinity toward sugars. Affinity of hydrolysis enzymes to adsorb onto the resin allowed for up to 92 % of the enzymatic activity to be recovered using a relatively low-molar NaCl wash solution. Integration of an ion exchange column with enzyme recovery into the proposed fed-batch hydrolysis process can improve the overall biorefinery efficiency and can greatly reduce the production costs of lignocellulosic biorenewable products.

  5. Automatic single- and multi-label enzymatic function prediction by machine learning

    Directory of Open Access Journals (Sweden)

    Shervine Amidi

    2017-03-01

    Full Text Available The number of protein structures in the PDB database has been increasing more than 15-fold since 1999. The creation of computational models predicting enzymatic function is of major importance since such models provide the means to better understand the behavior of newly discovered enzymes when catalyzing chemical reactions. Until now, single-label classification has been widely performed for predicting enzymatic function limiting the application to enzymes performing unique reactions and introducing errors when multi-functional enzymes are examined. Indeed, some enzymes may be performing different reactions and can hence be directly associated with multiple enzymatic functions. In the present work, we propose a multi-label enzymatic function classification scheme that combines structural and amino acid sequence information. We investigate two fusion approaches (in the feature level and decision level and assess the methodology for general enzymatic function prediction indicated by the first digit of the enzyme commission (EC code (six main classes on 40,034 enzymes from the PDB database. The proposed single-label and multi-label models predict correctly the actual functional activities in 97.8% and 95.5% (based on Hamming-loss of the cases, respectively. Also the multi-label model predicts all possible enzymatic reactions in 85.4% of the multi-labeled enzymes when the number of reactions is unknown. Code and datasets are available at https://figshare.com/s/a63e0bafa9b71fc7cbd7.

  6. Impact of high pressure processing on color, bioactive compounds, polyphenol oxidase activity, and microbiological attributes of pumpkin purée.

    Science.gov (United States)

    González-Cebrino, Francisco; Durán, Rocío; Delgado-Adámez, Jonathan; Contador, Rebeca; Bernabé, Rosario Ramírez

    2016-04-01

    Physicochemical parameters, bioactive compounds' content (carotenoids and total phenols), total antioxidant activity, and enzymatic activity of polyphenol oxidase (PPO) were evaluated after high pressure processing (HPP) on a pumpkin purée (cv. 'Butternut'). Three pressure levels (400, 500, and 600 MPa) were combined with three holding times (200, 400, and 600 s). The applied treatments reduced the levels of total aerobic mesophilic (TAM), total psychrophilic and psychrotrophic bacteria (TPP), and molds and yeasts (M&Y). All applied treatments did not affect enzymatic activity of PPO. Pressure level increased CIE L* values, which could enhance the lightness perception of high pressure (HP)-treated purées. No differences were found between the untreated and HP-treated purées regarding total phenols and carotenoids content (lutein, α-carotene, and β-carotene) and total antioxidant activity. HPP did not affect most quality parameters and maintained the levels of bioactive compounds. However, it did not achieve the complete inhibition of PPO, which could reduce the shelf-life of the pumpkin purée. © The Author(s) 2015.

  7. The enzymatic preparation of [α-32P]nucleoside triphosphates, cyclic [32P]AMP, and cyclic [32P]GMP

    International Nuclear Information System (INIS)

    Walseth, T.F.; Johnson, R.A.

    1979-01-01

    A method has been developed for the enzymatic preparation of α- 32 P-labelled ribo- and deoxyribonucleoside triphosphates, cyclic [ 32 P]AMP, and cyclic [ 32 P]GMP of high specific radioactivity and in high yield from 32 Psub(i). The method also enables the preparation of [γ- 32 P]ATP, [γ- 32 P]GTP, [γ- 32 P]ITP, and [γ- 32 P]-dATP of very high specific activity and in high yield. (Auth.)

  8. Enzymatic reduction of U(VI) in groundwaters

    International Nuclear Information System (INIS)

    Addelouas, A.; Gong, W.; Lutze, W.; Nuttall, E.; Fritz, B.; Crovisier, J.L.

    1999-01-01

    The use of enzymatic reduction of U(VI) in remediation of groundwater contaminated with U(VI) is receiving considerable attention. Certain strains of bacteria can combine the oxidation of an organic compound to the reduction of U(VI) to U(IV), which precipitates as uraninite. In the present study, we tested the reduction of U(VI) in groundwaters with various origins and compositions. In all groundwaters u(VI) was reduced by sulfate reducing bacteria that had been activated by ethanol and tri-metaphosphate. The reduction rate of U(VI) depends on sulfate concentration in water and the abundance of bacteria in the system. This work shows that bacteria capable of U(VI) reduction are ubiquitous in nature, and suggests the possibility of a large application of the enzymatic reduction of U(VI) for in situ clean up of groundwaters contaminated with uranium. (authors)

  9. Enzymatic Synthesis of the Flavone Glucosides, Prunin and Isoquercetin, and the Aglycones, Naringenin and Quercetin, with Selective α-L-Rhamnosidase and β-D-Glucosidase Activities of Naringinase

    Directory of Open Access Journals (Sweden)

    Hélder Vila-Real

    2011-01-01

    Full Text Available The production of flavonoid glycosides by removing rhamnose from rutinosides can be accomplished through enzymatic catalysis. Naringinase is an enzyme complex, expressing both α-L-rhamnosidase and β-D-glucosidase activities, with application in glycosides hydrolysis. To produce monoglycosylated flavonoids with naringinase, the expression of β-D-glucosidase activity is not desirable leading to the need of expensive methods for α-L-rhamnosidase purification. Therefore, the main purpose of this study was the inactivation of β-D-glucosidase activity expressed by naringinase keeping α-L-rhamnosidase with a high retention activity. Response surface methodology (RSM was used to evaluate the effects of temperature and pH on β-D-glucosidase inactivation. A selective inactivation of β-D-glucosidase activity of naringinase was achieved at 81.5∘C and pH 3.9, keeping a very high residual activity of α-L-rhamnosidase (78%. This was a crucial achievement towards an easy and cheap production method of very expensive flavonoids, like prunin and isoquercetin starting from naringin and rutin, respectively.

  10. Novel DDR Processing of Corn Stover Achieves High Monomeric Sugar Concentrations from Enzymatic Hydrolysis (230 g/L) and High Ethanol Concentration (10% v/v) During Fermentation

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xiaowen; Jennings, Ed; Shekiro, Joe; Kuhn, Erik M.; O' Brien, Marykate; Wang, Wei; Schell, Daniel J.; Himmel, Mike; Elander, Richard T.; Tucker, Melvin P.

    2015-04-03

    Distilling and purifying ethanol, butanol, and other products from second and later generation lignocellulosic biorefineries adds significant capital and operating cost for biofuels production. The energy costs associated with distillation affects plant gate and life cycle analysis costs. Lower titers in fermentation due to lower sugar concentrations from pretreatment increase both energy and production costs. In addition, higher titers decrease the volumes required for enzymatic hydrolysis and fermentation vessels. Therefore, increasing biofuels titers has been a research focus in renewable biofuels production for several decades. In this work, we achieved over 200 g/L of monomeric sugars after high solids enzymatic hydrolysis using the novel deacetylation and disc refining (DDR) process on corn stover. The high sugar concentrations and low chemical inhibitor concentrations from the DDR process allowed ethanol titers as high as 82 g/L in 22 hours, which translates into approximately 10 vol% ethanol. To our knowledge, this is the first time that 10 vol% ethanol in fermentation derived from corn stover without any sugar concentration or purification steps has been reported. Techno-economic analysis shows the higher titer ethanol achieved from the DDR process could significantly reduce the minimum ethanol selling price from cellulosic biomass.

  11. Combined pressure and cosolvent effects on enzyme activity - a high-pressure stopped-flow kinetic study on α-chymotrypsin.

    Science.gov (United States)

    Luong, Trung Quan; Winter, Roland

    2015-09-21

    We investigated the combined effects of cosolvents and pressure on the hydrolysis of a model peptide catalysed by α-chymotrypsin. The enzymatic activity was measured in the pressure range from 0.1 to 200 MPa using a high-pressure stopped-flow systems with 10 ms time resolution. A kosmotropic (trimethalymine-N-oxide, TMAO) and chaotropic (urea) cosolvent and mixtures thereof were used as cosolvents. High pressure enhances the hydrolysis rate as a consequence of a negative activation volume, ΔV(#), which, depending on the cosolvent system, amounts to -2 to -4 mL mol(-1). A more negative activation volume can be explained by a smaller compression of the ES complex relative to the transition state. Kinetic constants, such as kcat and the Michaelis constant KM, were determined for all solution conditions as a function of pressure. With increasing pressure, kcat increases by about 35% and its pressure dependence by a factor of 1.9 upon addition of 2 M urea, whereas 1 M TMAO has no significant effect on kcat and its pressure dependence. Similarly, KM increases upon addition of urea 6-fold. Addition of TMAO compensates the urea-effect on kcat and KM to some extent. The maximum rate of the enzymatic reaction increases with increasing pressure in all solutions except in the TMAO : urea 1 : 2 mixture, where, remarkably, pressure is found to have no effect on the rate of the enzymatic reaction anymore. Our data clearly show that compatible solutes can easily override deleterious effects of harsh environmental conditions, such as high hydrostatic pressures in the 100 MPa range, which is the maximum pressure encountered in the deep biosphere on Earth.

  12. Process development for gelatinisation and enzymatic hydrolysis of starch at high concentrations

    NARCIS (Netherlands)

    Baks, T.

    2007-01-01

    cum laude graduation (with distinction) Enzymatic hydrolysis of starch is encountered in day-to-day life for instance in the dishwasher during removal of stains with detergents or in our mouth during chewing of starch-based foods in the presence of saliva. The reaction is also important for the

  13. Bacterial Production and Enzymatic Activities in Deep-Sea Sediments of the Pacific Ocean: Biogeochemical Implications of Different Temperature Constraints

    Science.gov (United States)

    Danovaro, R.; Corinaldesi, C.; dell'Anno, A.

    2002-12-01

    The deep-sea bed, acting as the ultimate sink for organic material derived from the upper oceans primary production, is now assumed to play a key role in biogeochemical cycling of organic matter on global scale. Early diagenesis of organic matter in marine sediments is dependent upon biological processes (largely mediated by bacterial activity) and by molecular diffusion. Organic matter reaching the sea floor by sedimentation is subjected to complex biogeochemical transformations that make organic matter largely unsuitable for direct utilization by benthic heterotrophs. Extracellular enzymatic activities in the sediment is generally recognized as the key step in the degradation and utilization of organic polymers by bacteria and a key role in biopolymeric carbon mobilization is played by aminopeptidase, alkaline phosphatase and glucosidase activities. In the present study we investigated bacterial density, bacterial C production and exo-enzymatic activities (aminopeptidase, glucosidase and phosphatase activity) in deep-sea sediments of the Pacific Ocean in relation with the biochemical composition of sediment organic matter (proteins, carbohydrates and lipids), in order to gather information on organic matter cycling and diagenesis. Benthic viral abundance was also measured to investigate the potential role of viruses on microbial loop functioning. Sediment samples were collected at eight stations (depth ranging from 2070-3100 m) along two transects located at the opposite side (north and south) of ocean seismic ridge Juan Fernandez (along latitudes 33° 20' - 33° 40'), constituted by the submerged vulcanoes, which connects the Chilean coasts to Rapa Nui Island. Since the northern and southern sides of this ridge apparently displayed small but significant differences in deep-sea temperature (related to the general ocean circulation), this sampling strategy allowed also investigating the role of different temperature constraints on bacterial activity and

  14. Mechano-Enzymatic Deconstruction with a New Enzymatic Cocktail to Enhance Enzymatic Hydrolysis and Bioethanol Fermentation of Two Macroalgae Species

    Directory of Open Access Journals (Sweden)

    Sameh Amamou

    2018-01-01

    Full Text Available The aim of this study was to explore the efficiency of a mechano-enzymatic deconstruction of two macroalgae species for sugars and bioethanol production, by using a new enzymatic cocktail (Haliatase and two types of milling modes (vibro-ball: VBM and centrifugal milling: CM. By increasing the enzymatic concentration from 3.4 to 30 g/L, the total sugars released after 72 h of hydrolysis increased (from 6.7 to 13.1 g/100 g TS and from 7.95 to 10.8 g/100 g TS for the green algae U. lactuca and the red algae G. sesquipedale, respectively. Conversely, total sugars released from G. sesquipedale increased (up to 126% and 129% after VBM and CM, respectively. The best bioethanol yield (6 geth/100 g TS was reached after 72 h of fermentation of U. lactuca and no increase was obtained after centrifugal milling. The latter led to an enhancement of the ethanol yield of G. sesquipedale (from 2 to 4 g/100 g TS.

  15. High matrix metalloproteinase activity is a hallmark of periapical granulomas.

    Science.gov (United States)

    de Paula-Silva, Francisco Wanderley Garcia; D'Silva, Nisha J; da Silva, Léa Assed Bezerra; Kapila, Yvonne Lorraine

    2009-09-01

    The inability to distinguish periapical cysts from granulomas before performing root canal treatment leads to uncertainty in treatment outcomes because cysts have lower healing rates. Searching for differential expression of molecules within cysts or granulomas could provide information with regard to the identity of the lesion or suggest mechanistic differences that may form the basis for future therapeutic intervention. Thus, we investigated whether granulomas and cysts exhibit differential expression of extracellular matrix (ECM) molecules. Human periapical granulomas, periapical cysts, and healthy periodontal ligament tissues were used to investigate the differential expression of ECM molecules by microarray analysis. Because matrix metalloproteinases (MMP) showed the highest differential expression in the microarray analysis, MMPs were further examined by in situ zymography and immunohistochemistry. Data were analyzed by using one-way analysis of variance followed by the Tukey test. We observed that cysts and granulomas differentially expressed several ECM molecules, especially those from the MMP family. Compared with cysts, granulomas exhibited higher MMP enzymatic activity in areas stained for MMP-9. These areas were composed of polymorphonuclear cells (PMNs) in contrast to cysts. Similarly, MMP-13 was expressed by a greater number of cells in granulomas compared with cysts. Our findings indicate that high enzymatic MMP activity in PMNs together with MMP-9 and MMP-13 stained cells could be a molecular signature of granulomas unlike periapical cysts.

  16. Highly Atom Economic Synthesis of d?2?Aminobutyric Acid through an In?Vitro Tri?enzymatic Catalytic System

    OpenAIRE

    Chen, Xi; Cui, Yunfeng; Cheng, Xinkuan; Feng, Jinhui; Wu, Qiaqing; Zhu, Dunming

    2017-01-01

    Abstract d?2?Aminobutyric acid is an unnatural amino acid serving as an important intermediate in pharmaceutical production. Developing a synthetic method that uses cheaper starting materials and produces less by?product is a pressing demand. A tri?enzymatic catalytic system, which is composed of l?threonine ammonia lyase (l?TAL), d?amino acid dehydrogenase (d?AADH), and formate dehydrogenase (FDH), has thus been developed for the synthesis of d?2?aminobutyric acid with high optical purity. I...

  17. Structural and enzymatic characterization of the phosphotriesterase OPHC2 from Pseudomonas pseudoalcaligenes.

    Directory of Open Access Journals (Sweden)

    Guillaume Gotthard

    Full Text Available BACKGROUND: Organophosphates (OPs are neurotoxic compounds for which current methods of elimination are unsatisfactory; thus bio-remediation is considered as a promising alternative. Here we provide the structural and enzymatic characterization of the recently identified enzyme isolated from Pseudomonas pseudoalcaligenes dubbed OPHC2. OPHC2 belongs to the metallo-β-lactamase superfamily and exhibits an unusual thermal resistance and some OP degrading abilities. PRINCIPAL FINDINGS: The X-ray structure of OPHC2 has been solved at 2.1 Å resolution. The enzyme is roughly globular exhibiting a αβ/βα topology typical of the metallo-β-lactamase superfamily. Several structural determinants, such as an extended dimerization surface and an intramolecular disulfide bridge, common features in thermostable enzymes, are consistent with its high Tm (97.8°C. Additionally, we provide the enzymatic characterization of OPHC2 against a wide range of OPs, esters and lactones. SIGNIFICANCE: OPHC2 possesses a broad substrate activity spectrum, since it hydrolyzes various phosphotriesters, esters, and a lactone. Because of its organophosphorus hydrolase activity, and given its intrinsic thermostability, OPHC2 is an interesting candidate for the development of an OPs bio-decontaminant. Its X-ray structure shed light on its active site, and provides key information for the understanding of the substrate binding mode and catalysis.

  18. Hypolipidemic and Antioxidative Effects of Aqueous Enzymatic Extract from Rice Bran in Rats Fed a High-Fat and -Cholesterol Diet

    Science.gov (United States)

    Wang, Yu-Xin; Li, Yang; Sun, An-Min; Wang, Feng-Jiao; Yu, Guo-Ping

    2014-01-01

    Purpose: The aqueous enzymatic extract from rice bran (AEERB) was rich in protein, γ-oryzanol and tocols. The aim of this study was to investigate the effects of AEERB on the regulation of lipid metabolism and the inhibition of oxidative damage. Methods: The antioxidant activity of AEERB in vitro was measured in terms of radical scavenging capacity, ferric reducing ability power (FRAP) and linoleic acid emulsion system-ferric thiocyanate method (FTC). Male Wistar rats were fed with a normal diet and a high-fat and high-cholesterol diet with or without AEERB. After treatment, biochemical assays of serum, liver and feces lipid levels, the antioxidant enzyme activity, malondialdehyde (MDA) and protein carbonyl were determined. Result: AEERB is completely soluble in water and rich in hydrophilic and lipophilic functional ingredients. AEERB scavenged DPPH• and ABTS•+ and exhibited antioxidant activity slightly lower than that of ascorbic acid in the linoleic acid system. The administration of AEERB reduced serum lipid levels and the atherogenic index compared with those of the hyperlipidemic diet group (HD). The administration of AEERB significantly lowered liver lipid levels, inhibited hepatic 3-hydroxyl-3-methylglutaryl CoA reductase activity, and efficiently promoted the fecal excretion of total lipids and total cholesterol (TC) (p < 0.05). Dietary AEERB enhanced antioxidant status in the serum, liver and brain by increasing the antioxidant enzyme activity of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) and decreasing the content of MDA and protein carbonyl. Conclusions: The results indicated that AEERB might act as a potent hypolipidemic and antioxidant functional food. PMID:25230211

  19. Hypolipidemic and Antioxidative Effects of Aqueous Enzymatic Extract from Rice Bran in Rats Fed a High-Fat and -Cholesterol Diet

    Directory of Open Access Journals (Sweden)

    Yu-Xin Wang

    2014-09-01

    Full Text Available Purpose: The aqueous enzymatic extract from rice bran (AEERB was rich in protein, γ-oryzanol and tocols. The aim of this study was to investigate the effects of AEERB on the regulation of lipid metabolism and the inhibition of oxidative damage. Methods: The antioxidant activity of AEERB in vitro was measured in terms of radical scavenging capacity, ferric reducing ability power (FRAP and linoleic acid emulsion system-ferric thiocyanate method (FTC. Male Wistar rats were fed with a normal diet and a high-fat and high-cholesterol diet with or without AEERB. After treatment, biochemical assays of serum, liver and feces lipid levels, the antioxidant enzyme activity, malondialdehyde (MDA and protein carbonyl were determined. Result: AEERB is completely soluble in water and rich in hydrophilic and lipophilic functional ingredients. AEERB scavenged DPPH• and ABTS•+ and exhibited antioxidant activity slightly lower than that of ascorbic acid in the linoleic acid system. The administration of AEERB reduced serum lipid levels and the atherogenic index compared with those of the hyperlipidemic diet group (HD. The administration of AEERB significantly lowered liver lipid levels, inhibited hepatic 3-hydroxyl-3-methylglutaryl CoA reductase activity, and efficiently promoted the fecal excretion of total lipids and total cholesterol (TC (p < 0.05. Dietary AEERB enhanced antioxidant status in the serum, liver and brain by increasing the antioxidant enzyme activity of superoxide dismutase (SOD, catalase (CAT, and glutathione peroxidase (GSH-Px and decreasing the content of MDA and protein carbonyl. Conclusions: The results indicated that AEERB might act as a potent hypolipidemic and antioxidant functional food.

  20. Hypolipidemic and antioxidative effects of aqueous enzymatic extract from rice bran in rats fed a high-fat and -cholesterol diet.

    Science.gov (United States)

    Wang, Yu-Xin; Li, Yang; Sun, An-Min; Wang, Feng-Jiao; Yu, Guo-Ping

    2014-09-16

    The aqueous enzymatic extract from rice bran (AEERB) was rich in protein, γ-oryzanol and tocols. The aim of this study was to investigate the effects of AEERB on the regulation of lipid metabolism and the inhibition of oxidative damage. The antioxidant activity of AEERB in vitro was measured in terms of radical scavenging capacity, ferric reducing ability power (FRAP) and linoleic acid emulsion system-ferric thiocyanate method (FTC). Male Wistar rats were fed with a normal diet and a high-fat and high-cholesterol diet with or without AEERB. After treatment, biochemical assays of serum, liver and feces lipid levels, the antioxidant enzyme activity, malondialdehyde (MDA) and protein carbonyl were determined. AEERB is completely soluble in water and rich in hydrophilic and lipophilic functional ingredients. AEERB scavenged DPPH• and ABTS•+ and exhibited antioxidant activity slightly lower than that of ascorbic acid in the linoleic acid system. The administration of AEERB reduced serum lipid levels and the atherogenic index compared with those of the hyperlipidemic diet group (HD). The administration of AEERB significantly lowered liver lipid levels, inhibited hepatic 3-hydroxyl-3-methylglutaryl CoA reductase activity, and efficiently promoted the fecal excretion of total lipids and total cholesterol (TC) (p < 0.05). Dietary AEERB enhanced antioxidant status in the serum, liver and brain by increasing the antioxidant enzyme activity of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) and decreasing the content of MDA and protein carbonyl. The results indicated that AEERB might act as a potent hypolipidemic and antioxidant functional food.

  1. Enzymatic assays for the diagnosis of bradykinin-dependent angioedema.

    Directory of Open Access Journals (Sweden)

    Federica Defendi

    Full Text Available BACKGROUND: The kinins (primarily bradykinin, BK represent the mediators responsible for local increase of vascular permeability in hereditary angioedema (HAE, HAE I-II associated with alterations of the SERPING1 gene and HAE with normal C1-Inhibitor function (HAE-nC1INH. Besides C1-Inhibitor function and concentration, no biological assay of kinin metabolism is actually available to help physicians for the diagnosis of angioedema (AE. We describe enzymatic tests on the plasma for diagnosis of BK-dependent AE. METHODS: The plasma amidase assays are performed using the Pro-Phe-Arg-p-nitroanilide peptide substrate to evaluate the spontaneous amidase activity and the proenzyme activation. We analyzed data of 872 patients presenting with BK-dependent AE or BK-unrelated diseases, compared to 303 controls. Anti-high MW kininogen (HK immunoblot was achieved to confirm HK cleavage in exemplary samples. Reproducibility, repeatability, limit of blank, limit of detection, precision, linearity and receiver operating characteristics (ROC were used to calculate the diagnostic performance of the assays. RESULTS: Spontaneous amidase activity was significantly increased in all BK-dependent AE, associated with the acute phase of disease in HAE-nC1INH, but preserved in BK-unrelated disorders. The increase of the amidase activity was associated to HK proteolysis, indicating its relevance to identify kininogenase activity. The oestrogens, known for precipitating AE episodes, were found as triggers of enzymatic activity. Calculations from ROC curves gave the optimum diagnostic cut-off for women (9.3 nmol⋅min(-1⋅mL(-1, area under curve [AUC] 92.1%, sensitivity 80.0%, and specificity 90.1% and for men (6.6 nmol·min(-1⋅mL(-1, AUC 91.0%, sensitivity 87.0% and specificity 81.2%. CONCLUSION: The amidase assay represents a diagnostic tool to help physicians in the decision to distinguish between BK-related and -unrelated AE.

  2. A singular enzymatic megacomplex from Bacillus subtilis.

    Science.gov (United States)

    Straight, Paul D; Fischbach, Michael A; Walsh, Christopher T; Rudner, David Z; Kolter, Roberto

    2007-01-02

    Nonribosomal peptide synthetases (NRPS), polyketide synthases (PKS), and hybrid NRPS/PKS are of particular interest, because they produce numerous therapeutic agents, have great potential for engineering novel compounds, and are the largest enzymes known. The predicted masses of known enzymatic assembly lines can reach almost 5 megadaltons, dwarfing even the ribosome (approximately 2.6 megadaltons). Despite their uniqueness and importance, little is known about the organization of these enzymes within the native producer cells. Here we report that an 80-kb gene cluster, which occupies approximately 2% of the Bacillus subtilis genome, encodes the subunits of approximately 2.5 megadalton active hybrid NRPS/PKS. Many copies of the NRPS/PKS assemble into a single organelle-like membrane-associated complex of tens to hundreds of megadaltons. Such an enzymatic megacomplex is unprecedented in bacterial subcellular organization and has important implications for engineering novel NRPS/PKSs.

  3. High-performance liquid chromatography analysis methods developed for quantifying enzymatic esterification of flavonoids in ionic liquids

    DEFF Research Database (Denmark)

    Lue, Bena-Marie; Guo, Zheng; Xu, X.B.

    2008-01-01

    Methods using reversed-phase high-performance liquid chromatography (RP-HPLC) with ELSD were investigated to quantify enzymatic reactions of flavonoids with fatty acids in the presence of diverse room temperature ionic liquids (RTILs). A buffered salt (preferably triethylamine-acetate) was found...... essential for separation of flavonoids from strongly polar RTILs, whereby RTILs were generally visible as two major peaks identified based on an ion-pairing/exchanging hypothesis. C8 and C12 stationary phases were optimal while mobile phase pH (3-7) had only a minor influence on separation. The method...

  4. Green-synthesized CdS nano-pesticides: Toxicity on young instars of malaria vectors and impact on enzymatic activities of the non-target mud crab Scylla serrata.

    Science.gov (United States)

    Sujitha, Vasu; Murugan, Kadarkarai; Dinesh, Devakumar; Pandiyan, Amuthvalli; Aruliah, Rajasekar; Hwang, Jiang-Shiou; Kalimuthu, Kandasamy; Panneerselvam, Chellasamy; Higuchi, Akon; Aziz, Al Thabiani; Kumar, Suresh; Alarfaj, Abdullah A; Vaseeharan, Baskaralingam; Canale, Angelo; Benelli, Giovanni

    2017-07-01

    Currently, nano-formulated mosquito larvicides have been widely proposed to control young instars of malaria vector populations. However, the fate of nanoparticles in the aquatic environment is scarcely known, with special reference to the impact of nanoparticles on enzymatic activity of non-target aquatic invertebrates. In this study, we synthesized CdS nanoparticles using a green protocol relying on the cheap extract of Valoniopsis pachynema algae. CdS nanoparticles showed high toxicity on young instars of the malaria vectors Anopheles stephensi and A. sundaicus. The antimalarial activity of the nano-synthesized product against chloroquine-resistant (CQ-r) Plasmodium falciparum parasites was investigated. From a non-target perspective, we focused on the impact of this novel nano-pesticide on antioxidant enzymes acetylcholinesterase (AChE) and glutathione S-transferase (GST) activities of the mud crab Scylla serrata. The characterization of nanomaterials was carried out by UV-vis and FTIR spectroscopy, as well as SEM and XRD analyses. In mosquitocidal assays, LC 50 of V. pachynema-synthesized CdS nanoparticles on A. stephensi ranged from 16.856 (larva I), to 30.301μg/ml (pupa), while for An. sundaicus they ranged from 13.584 to 22.496μg/ml. The antiplasmodial activity of V. pachynema extract and CdS nanoparticles was evaluated against CQ-r and CQ-sensitive (CQ-s) strains of Plasmodium falciparum. IC 50 of V. pachynema extract was 58.1μg/ml (CQ-s) and 71.46μg/ml (CQ-r), while nano-CdS IC 50 was 76.14μg/ml (CQ-s) and 89.21μg/ml (CQ-r). In enzymatic assays, S. serrata crabs were exposed to sub-lethal concentrations, i.e. 4, 6 and 8μg/ml of CdS nanoparticles, assessing changes in GST and AChE activity after 16days. We observed significantly higher activity of GST, if compared to the control, during the whole experiment period. In addition, a single treatment with CdS nanoparticles led to a significant decrease in AChE activity over time. The toxicity of Cd

  5. High-performance non-enzymatic catalysts based on 3D hierarchical hollow porous Co3O4 nanododecahedras in situ decorated on carbon nanotubes for glucose detection and biofuel cell application.

    Science.gov (United States)

    Wang, Shiyue; Zhang, Xiaohua; Huang, Junlin; Chen, Jinhua

    2018-03-01

    In this work, high-performance non-enzymatic catalysts based on 3D hierarchical hollow porous Co 3 O 4 nanododecahedras in situ decorated on carbon nanotubes (3D Co 3 O 4 -HPND/CNTs) were successfully prepared via direct carbonizing metal-organic framework-67 in situ grown on carbon nanotubes. The morphology, microstructure, and composite of 3D Co 3 O 4 -HPND/CNTs were characterized by scanning electron microscopy, transmission electron microscopy, micropore and chemisorption analyzer, and X-ray diffraction. The electrochemical characterizations indicated that 3D Co 3 O 4 -HPND/CNTs present considerably catalytic activity toward glucose oxidation and could be promising for constructing high-performance electrochemical non-enzymatic glucose sensors and glucose/O 2 biofuel cell. When used for non-enzymatic glucose detection, the 3D Co 3 O 4 -HPND/CNTs modified glassy carbon electrode (3D Co 3 O 4 -HPND/CNTs/GCE) exhibited excellent analytical performance with high sensitivity (22.21 mA mM -1  cm -2 ), low detection limit of 0.35 μM (S/N = 3), fast response (less than 5 s) and good stability. On the other hand, when the 3D Co 3 O 4 -HPND/CNTs/GCE worked as an anode of a biofuel cell, a maximum power density of 210 μW cm -2 at 0.15 V could be obtained, and the open circuit potential was 0.68 V. The attractive 3D hierarchical porous structural features, the large surface area, and the excellent conductivity based on the continuous and effective electron transport network in 3D Co 3 O 4 -HPND/CNTs endow 3D Co 3 O 4 -HPND/CNTs with the enhanced electrochemical performance and promising applications in electrochemical sensing, biofuel cell, and other energy storage and conversion devices such as supercapacitor. Graphical abstract High-performance non-enzymatic catalysts for enzymeless glucose sensing and biofuel cell based on 3D hierarchical hollow porous Co 3 O 4 nanododecahedras anchored on carbon nanotubes were successfully prepared via direct carbonizing

  6. MnO_x/C nanocomposite: An insight on high-performance supercapacitor and non-enzymatic hydrogen peroxide detection

    International Nuclear Information System (INIS)

    Ahuja, Preety; Kumar Ujjain, Sanjeev; Kanojia, Rajni

    2017-01-01

    Graphical abstract: In-situ inclusion of carbon matrix during growth of MnO_x nanoparticles resulted in MnO_x/C nanocomposite with enhanced electronic diffusion leading to high energy/power densities supercapacitor and highly sensitive H_2O_2 sensor. - Highlights: • MnO_x/C, synthesized via microemulsion method, is electrochemically investigated towards supercapacitor and sensing applications. • In-situ inclusion of conducting carbon in manganese oxide enhances the network conductivity facilitating the charge transfer process. • It provides high energy and power density, 31.6 Wh kg"−"1 and 3.8 kW kg"−"1 respectively, with short relaxation time ∼3 ms for fabricated cell. • MnO_x/C as sensor, exhibits excellent catalytic activity toward H_2O_2 oxidation and offer high sensitivity with low detection limit. - Abstract: In this work, we have used microemulsion method for synthesis of MnO_x/C nanocomposite and investigated its electrochemical properties via fabrication of supercapacitor and non-enzymatic hydrogen peroxide (H_2O_2) sensor. In-situ inclusion of conducting carbon in manganese oxide (MnO_x/C) enhances the network conductivity facilitating the charge transfer process which is beneficial for supercapacitor and sensing applications. MnO_x/C provides high energy and power density, 31.6 Wh kg"−"1 and 3.8 kW kg"−"1 respectively and short relaxation time ∼3 ms for fabricated cell (MnO_x/C//MnO_x/C) endowing excellent power delivery capacity. Furthermore, MnO_x/C as sensor, exhibits excellent catalytic activity toward the oxidation of H_2O_2 and shows high sensitivity (0.37 mA mM"−"1 cm"−"2) with low detection limit (0.5 μM at an S/N of 3). Hence, this study provides new avenue for high performance supercapacitor and H_2O_2 detection.

  7. Enzymatic labelling of. gamma. -globulin and insulin with iodine-125

    Energy Technology Data Exchange (ETDEWEB)

    Lucka, B; Russin, K [Institute of Nuclear Physics, Krakow (Poland)

    1979-01-01

    The parameters of enzymatic labelling of proteins with iodine 125 were examined. The manner and sequence of reagent addition, the effects of reagent concentration, reaction time and total Na/sup 125/I activity on the labelling yield were determined.

  8. Enzymatic saccharification of dilute acid pretreated saline crops for fermentable sugar production

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Yi; Zhang, Ruihong [Biological and Agricultural Engineering Department, University of California, Davis One Shields Avenue, Davis, CA 95616 (United States); Pan, Zhongli [Biological and Agricultural Engineering Department, University of California, Davis One Shields Avenue, Davis, CA 95616 (United States); Processed Foods Research Unit, USDA-ARS-WRRC, 800 Buchanan Street, Albany, CA 94710 (United States); Wang, Donghai [Biological and Agricultural Engineering Department, Kansas State University, Manhattan, KS 66506 (United States)

    2009-11-15

    Four saline crops [athel (Tamarix aphylla L), eucalyptus (Eucalyptus camaldulensis), Jose Tall Wheatgrass (Agropyron elongatum), and Creeping Wild Ryegrass (Leymus triticoides)] that are used in farms for salt uptake from soil and drainage irrigation water have the potential for fuel ethanol production because they don't take a large number of arable lands. Dilute sulfuric acid pretreatment and enzymatic hydrolysis were conducted to select the optimum pretreatment conditions and the best saline crop for further enzymatic hydrolysis research. The optimum dilute acid pretreatment conditions included T = 165 C, t = 8 min, and sulfuric acid concentration 1.4% (w/w). Creeping Wild Ryegrass was decided to be the best saline crop. Solid loading, cellulase and {beta}-glucosidase concentrations had significant effects on the enzymatic hydrolysis of dilute acid pretreated Creeping Wild Ryegrass. Glucose concentration increased by 36 mg/mL and enzymatic digestibility decreased by 20% when the solid loading increased from 4 to 12%. With 8% solid loading, enzymatic digestibility increased by over 30% with the increase of cellulase concentration from 5 to 15 FPU/g-cellulose. Under given cellulase concentration of 15 FPU/g-cellulose, 60% increase of enzymatic digestibility of pretreated Creeping Wild Ryegrass was obtained with the increase of {beta}-glucosidase concentration up to 15 CBU/g-cellulose. With a high solid loading of 10%, fed-batch operation generated 12% and 18% higher enzymatic digestibility and glucose concentration, respectively, than batch process. (author)

  9. Enzymatic Detoxication, Conformational Selection, and the Role of Molten Globule Active Sites*

    Science.gov (United States)

    Honaker, Matthew T.; Acchione, Mauro; Zhang, Wei; Mannervik, Bengt; Atkins, William M.

    2013-01-01

    The role of conformational ensembles in enzymatic reactions remains unclear. Discussion concerning “induced fit” versus “conformational selection” has, however, ignored detoxication enzymes, which exhibit catalytic promiscuity. These enzymes dominate drug metabolism and determine drug-drug interactions. The detoxication enzyme glutathione transferase A1–1 (GSTA1–1), exploits a molten globule-like active site to achieve remarkable catalytic promiscuity wherein the substrate-free conformational ensemble is broad with barrierless transitions between states. A quantitative index of catalytic promiscuity is used to compare engineered variants of GSTA1–1 and the catalytic promiscuity correlates strongly with characteristics of the thermodynamic partition function, for the substrate-free enzymes. Access to chemically disparate transition states is encoded by the substrate-free conformational ensemble. Pre-steady state catalytic data confirm an extension of the conformational selection model, wherein different substrates select different starting conformations. The kinetic liability of the conformational breadth is minimized by a smooth landscape. We propose that “local” molten globule behavior optimizes detoxication enzymes. PMID:23649628

  10. Effect of topical application of fluoride gel NaF 2% on enzymatic and non-enzymatic antioxidant parameters of saliva.

    Science.gov (United States)

    Leite, Mariana Ferreira; Ferreira, Nayara Ferraz D'Assumpção; Shitsuka, Caleb David Willy Moreira; Lima, Amanda Martins; Masuyama, Mônica Miyuki; Sant'Anna, Giselle Rodrigues; Yamaguti, Paula Mochidome; Polotow, Tatiana G; de Barros, Marcelo Paes

    2012-06-01

    The aim of the study was to evaluate the effect of topical fluoride gel NaF 2% application on antioxidant parameters of whole saliva from children. The saliva mechanically stimulated with parafilm was collected from 25 children (6-12 years) attending the Clinic of Paediatric Dentistry of Universidade Cruzeiro do Sul, São Paulo, Brazil, before (control group) and immediately after application of neutral fluoride gel NaF 2% (fluoride-gel group), according to the Standards for Research Using Human Subjects, Resolution 196/96 of the USA National Health Council of 10/10/1996. Afterwards, pre-post ferric-reducing antioxidant power (FRAP), trolox-equivalent antioxidant capacity (TEAC), uric acid, reduced/oxidised glutathione content (GSH/GSSG) and total peroxidase activity (TPO) were evaluated in whole saliva of both groups. All non-enzymatic antioxidant parameters were augmented by fluoride-gel NaF 2% application, whereas a notable reduction (31%) of peroxidase activity was concomitantly observed in the children's saliva (p ≤ 0.05). Nevertheless, the reducing power of saliva was kept unaltered under these circumstances (p ≤ 0.05). Despite the reduced activity of peroxidase (an important antimicrobial and antioxidant enzyme), the topical fluoride gel NaF 2% favourably stimulated the release of non-enzymatic antioxidant components of saliva, sustaining the reducing power of saliva and the natural defences of the oral cavity. Copyright © 2011 Elsevier Ltd. All rights reserved.

  11. Lignocellulose pretreatment technologies affect the level of enzymatic cellulose oxidation by LPMO

    DEFF Research Database (Denmark)

    Rodríguez-Zúñiga, Ursula Fabiola; Cannella, David; de Campos Giordano, Roberto

    2015-01-01

    of the cellulose oxidizing enzyme lytic polysaccharide monooxygenase (LPMO). The highest activity of LPMO was observed for the hydrothermally pretreated biomasses, which also contained the highest level of lignin. All hydrolysis were done at high dry matter levels, using a commercial enzyme preparation containing......Sugarcane bagasse, corn stover, and wheat straw are among the most available resources for production of cellulosic ethanol. For these biomasses we study the influence of pre-treatment methods on the chemical composition, as well as on the subsequent reactions of enzymatic hydrolysis and oxidation...

  12. Cerebral ischemia is exacerbated by extracellular nicotinamide phosphoribosyltransferase via a non-enzymatic mechanism.

    Directory of Open Access Journals (Sweden)

    Bing Zhao

    Full Text Available Intracellular nicotinamide phosphoribosyltransferase (iNAMPT in neuron has been known as a protective factor against cerebral ischemia through its enzymatic activity, but the role of central extracellular NAMPT (eNAMPT is not clear. Here we show that eNAMPT protein level was elevated in the ischemic rat brain after middle-cerebral-artery occlusion (MCAO and reperfusion, which can be traced to at least in part from blood circulation. Administration of recombinant NAMPT protein exacerbated MCAO-induced neuronal injury in rat brain, while exacerbated oxygen-glucose-deprivation (OGD induced neuronal injury only in neuron-glial mixed culture, but not in neuron culture. In the mixed culture, NAMPT protein promoted TNF-α release in a time- and concentration-dependent fashion, while TNF-α neutralizing antibody protected OGD-induced, NAMPT-enhanced neuronal injury. Importantly, H247A mutant of NAMPT with essentially no enzymatic activity exerted similar effects on ischemic neuronal injury and TNF-α release as the wild type protein. Thus, eNAMPT is an injurious and inflammatory factor in cerebral ischemia and aggravates ischemic neuronal injury by triggering TNF-α release from glia cells, via a mechanism not related to NAMPT enzymatic activity.

  13. IMPACT OF ALTITUDES ON SOIL CHARACTERISTICS AND ENZYMATIC ACTIVITIES IN FOREST AND FALLOW LANDS OF ALMORA DISTRICT OF CENTRAL HIMALAYA

    OpenAIRE

    B. R. Maurya; Vimal Singh; P. P. Dhyani

    2014-01-01

    Abstract: Altitude is one of the major topographical factors which influence the fertility status of soil. Population explosion has rooted deforestation at different altitudes to bring more area under cultivation leading to fallow lands. Objective of this study was to assess the impact of altitude on electro-chemical properties and enzymatic activities of forest and fallow land soils of Almora district of Central Himalaya. Seventy soil samples were collected from different altitudes of forest...

  14. Unraveling the enzymatic basis of wine flavorome: a phylo-functional study of wine related yeast species

    Directory of Open Access Journals (Sweden)

    Ignacio eBelda

    2016-01-01

    Full Text Available Non-Saccharomyces yeasts are a heterogeneous microbial group involved in the early stages of wine fermentation. The high enzymatic potential of these yeasts makes them a useful tool for increasing the final organoleptic characteristics of wines in spite of their low fermentative power. Their physiology and contribution to wine quality are still poorly understood, with most current knowledge being acquired empirically and in most cases based in single species and strains. This work analyzed the metabolic potential of 770 yeast isolates from different enological origins and representing 15 different species, by studying their production of enzymes of enological interest and linking phylogenetic and enzymatic data. The isolates were screened for glycosidase enzymes related to terpene aroma release, the β-lyase activity responsible for the release of volatile thiols, and sulfite reductase. Apart from these aroma-related activities, protease, polygalacturonase and cellulase activities were also studied in the entire yeast collection, being related to the improvement of different technological and sensorial features of wines. In this context, and in terms of abundance, two different groups were established, with α-L-arabinofuranosidase, polygalacturonase and cellulase being the less abundant activities. By contrast, β-glucosidase and protease activities were widespread in the yeast collection studied.A classical phylogenetic study involving the partial sequencing of 26S rDNA was conducted in conjunction with the enzymatic profiles of the 770 yeast isolates for further typing, complementing the phylogenetic relationships established by using 26S rDNA. This has rendered it possible to foresee the contribution different yeast species make to wine quality and their potential applicability as pure inocula, establishing species-specific behavior. These consistent results allowed us to design future targeted studies on the impact different non

  15. Effect of aflatoxin B1 on growth and enzymatic activity of a native strain of Bacillus sp Efecto de la aflatoxina B1 sobre el crecimiento y actividad proteolítica de una cepa nativa de Bacillus sp

    Directory of Open Access Journals (Sweden)

    Márquez Edna Judith

    2004-07-01

    Full Text Available The effect of different aflatoxin B1 (AFAB1 concentrations on alkaline protease growth and enzymatic activity was evaluated; a native strain of alkalophilic Bacillus sp cultivated in CSL (Corn Steep Liquor was used. It was found that the effect of AFAB1 on the strain inhibited its growth and enzymatic activity to 1 ppm, showing that the strain is highly sensible to AFAB1, meaning that medium obtained f rom Colombian corn contaminated with this mycotoxin cannot be easily used. Concentrations less than 0.1 ppm did not affect growth and enzymatic activity. Key words: Bacillus, aflatoxin, alkaline proteases.Se evaluó el efecto de diferentes concentraciones de aflatoxina B1 (AFAB1 sobre el crecimiento y actividad enzimática de proteasas alcalinas de una cepa nativa de Bacillus sp Alcalofílico cultivada en LAM (Licor Agotado de Maíz. Se encontró que la cepa inhibe su crecimiento y actividad enzimática a 1 ppm, lo que demuestra una alta sensibilidad de la cepa evaluada a la AFAB1 e imposibilita utilizar fácilmente medios obtenidos de maíz nacional contaminado con esta micotoxina. Las concentraciones inferiores a 0.1 ppm no tienen ningún efecto sobre el crecimiento y la actividad enzimática. Palabras clave: Bacillus, aflatoxina, proteasas alcalinas.

  16. Interaction with Single-stranded DNA-binding Protein Stimulates Escherichia coli Ribonuclease HI Enzymatic Activity.

    Science.gov (United States)

    Petzold, Christine; Marceau, Aimee H; Miller, Katherine H; Marqusee, Susan; Keck, James L

    2015-06-05

    Single-stranded (ss) DNA-binding proteins (SSBs) bind and protect ssDNA intermediates formed during replication, recombination, and repair reactions. SSBs also directly interact with many different genome maintenance proteins to stimulate their enzymatic activities and/or mediate their proper cellular localization. We have identified an interaction formed between Escherichia coli SSB and ribonuclease HI (RNase HI), an enzyme that hydrolyzes RNA in RNA/DNA hybrids. The RNase HI·SSB complex forms by RNase HI binding the intrinsically disordered C terminus of SSB (SSB-Ct), a mode of interaction that is shared among all SSB interaction partners examined to date. Residues that comprise the SSB-Ct binding site are conserved among bacterial RNase HI enzymes, suggesting that RNase HI·SSB complexes are present in many bacterial species and that retaining the interaction is important for its cellular function. A steady-state kinetic analysis shows that interaction with SSB stimulates RNase HI activity by lowering the reaction Km. SSB or RNase HI protein variants that disrupt complex formation nullify this effect. Collectively our findings identify a direct RNase HI/SSB interaction that could play a role in targeting RNase HI activity to RNA/DNA hybrid substrates within the genome. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  17. Interaction with Single-stranded DNA-binding Protein Stimulates Escherichia coli Ribonuclease HI Enzymatic Activity*

    Science.gov (United States)

    Petzold, Christine; Marceau, Aimee H.; Miller, Katherine H.; Marqusee, Susan; Keck, James L.

    2015-01-01

    Single-stranded (ss) DNA-binding proteins (SSBs) bind and protect ssDNA intermediates formed during replication, recombination, and repair reactions. SSBs also directly interact with many different genome maintenance proteins to stimulate their enzymatic activities and/or mediate their proper cellular localization. We have identified an interaction formed between Escherichia coli SSB and ribonuclease HI (RNase HI), an enzyme that hydrolyzes RNA in RNA/DNA hybrids. The RNase HI·SSB complex forms by RNase HI binding the intrinsically disordered C terminus of SSB (SSB-Ct), a mode of interaction that is shared among all SSB interaction partners examined to date. Residues that comprise the SSB-Ct binding site are conserved among bacterial RNase HI enzymes, suggesting that RNase HI·SSB complexes are present in many bacterial species and that retaining the interaction is important for its cellular function. A steady-state kinetic analysis shows that interaction with SSB stimulates RNase HI activity by lowering the reaction Km. SSB or RNase HI protein variants that disrupt complex formation nullify this effect. Collectively our findings identify a direct RNase HI/SSB interaction that could play a role in targeting RNase HI activity to RNA/DNA hybrid substrates within the genome. PMID:25903123

  18. STUDY ON QUALITY PARAMETERS AND ENZYMATIC ACTIVITY OF GRAIN MILL PRODUCTS REGION IN TRANSYLVANIA

    Directory of Open Access Journals (Sweden)

    Glevitzky Mirel

    2011-07-01

    Full Text Available This paper aims at determining the main quality parameters of grain mill products in the Transylvania region, also studying and emphasizing the enzymatic activity of flour. Determination of quality characteristics of grain mill products entails establishing physical, chemical and sensory parameters and assessing them against the limits imposed by law. Analysis was performed on samples formed by mixing basic medium extracted from different batches. Incremental size, sampling tools, how to extract them, the training sample and laboratory environments, packaging and labeling of samples were performed according to STAS 1068 69. Determination of the fall (Falling Number, an empirical test that relies on the ability of endogenous ?-amylase to reduce viscosity of the treated warm flour suspension is used, large scale milling and bakery industry to predict and assess the Baking quality of flour. In sprouted wheat, characterised by a low Falling number, dextrin produced by the action of ?-amylase leads to a sticky bread core. Experiments suggest that the values fall turnover (FN does not shrink in direct proportion to the percentage of germinating seeds. Amylolytic activity depends on the stage of sprouting of grains. Lack of ?-amylase activity can be corrected by adding malt grain ?-amylase or fungal ?-amylase.

  19. CONTINUOUS AND SEMICONTINUOUS REACTION SYSTEMS FOR HIGH-SOLIDS ENZYMATIC HYDROLYSIS OF LIGNOCELLULOSICS

    Directory of Open Access Journals (Sweden)

    A. González Quiroga

    2015-12-01

    Full Text Available Abstract An attractive operation strategy for the enzymatic hydrolysis of lignocellulosics results from dividing the process into three stages with complementary goals: continuous enzyme adsorption at low-solids loading (5% w/w with recycling of the liquid phase; continuous liquefaction at high-solids content (up to 20% w/w; and, finally, continuous or semicontinuous hydrolysis with supplementation of fresh enzymes. This paper presents a detailed modeling and simulation framework for the aforementioned operation strategies. The limiting micromixing situations of macrofluid and microfluid are used to predict conversions. The adsorption and liquefaction stages are modeled as a continuous stirred tank and a plug flow reactor, respectively. Two alternatives for the third stage are studied: a train of five cascading stirred tanks and a battery of batch reactors in parallel. Simulation results show that glucose concentrations greater than 100 g L-1 could be reached with both of the alternatives for the third stage.

  20. Process technology for multi-enzymatic reaction systems

    DEFF Research Database (Denmark)

    Xue, Rui; Woodley, John M.

    2012-01-01

    In recent years, biocatalysis has started to provide an important green tool in synthetic organic chemistry. Currently, the idea of using multi-enzymatic systems for industrial production of chemical compounds becomes increasingly attractive. Recent examples demonstrate the potential of enzymatic...... synthesis and fermentation as an alternative to chemical-catalysis for the production of pharmaceuticals and fine chemicals. In particular, the use of multiple enzymes is of special interest. However, many challenges remain in the scale-up of a multi-enzymatic system. This review summarizes and discusses...... the technology options and strategies that are available for the development of multi-enzymatic processes. Some engineering tools, including kinetic models and operating windows, for developing and evaluating such processes are also introduced....

  1. Plant oligoadenylates: enzymatic synthesis, isolation, and biological activities

    International Nuclear Information System (INIS)

    Devash, Y.; Reichman, M.; Sela, I.; Reichenbach, N.L.; Suhadolnik, R.J.

    1985-01-01

    An enzyme that converts [ 3 H, 32 P]ATP, with a 3 H: 32 P ratio of 1:1, to oligoadenylates with the same 3 H: 32 P ratio was increased in plants following treatment with human leukocyte interferon or plant antiviral factor or inoculation with tobacco mosaic virus. The enzyme was extracted from tobacco leaves, callus tissue cultures, or cell suspension cultures. The enzyme, a putative plant oligoadenylate synthetase, was immobilized on poly(rI) . poly(rC)-agarose columns and converted ATP into plant oligoadenylates. These oligoadenylates were displaced from DEAE-cellulose columns with 350 mM KCl buffer, dialyzed, and further purified by high-performance liquid chromatography (HPLC) and DEAE-cellulose gradient chromatography. In all steps of purification, the ratio of 3 H: 32 P in the oligoadenylates remained 1:1. The plant oligoadenylates isolated by displacement with 350 mM KCl had a molecular weight greater than 1000. The plant oligoadenylates had charges of 5- and 6-. HPLC resolved five peaks, three of which inhibited protein synthesis in reticulocyte and wheat germ systems. Partial structural elucidation of the plant oligoadenylates has been determined by enzymatic and chemical treatments. An adenylate with a 3',5'-phosphodiester and/or a pyrophosphoryl linkage with either 3'- or 5'-terminal phosphates is postulated on the basis of treatment of the oligoadenylates with T2 RNase, snake venom phosphodiesterase, and bacterial alkaline phosphatase and acid and alkaline hydrolyses. The plant oligoadenylates at 8 X 10(-7) M inhibit protein synthesis by 75% in lysates from rabbit reticulocytes and 45% in wheat germ cell-free systems

  2. Use of [1,2-3 h] testosterone in 5 α- reductase enzymatic activity dosing in dermal fibroblast cultures from polycystic ovarian patients

    International Nuclear Information System (INIS)

    Matei, Lidia; Postolache, Cristian; Condac, Eduard

    2003-01-01

    Polycystic ovarian syndrome is an endocrine malady very frequent in women characterized by the presence of ovarian cysts, visible or not by ultrasonography, menstrual cycle deregulation and sometimes by high plasmatic concentrations of androgen hormones. Many cases of polycystic syndrome could not be easily diagnosed or had an erroneous diagnostic. Therefore, is useful to know the plasmatic androgen hormone profile. This profile could indicate the cause for observed clinical manifestations; this cause may be observed in ovarian, suprarenal glands or hypothalamo-hypophysis level. In vitro studies on dermal fibroblasts permit the detail determination of steroid hormones metabolism in target organs and offer important information regarding action mechanism. This study follows the identification of testosterone metabolites in fibroblasts and enzymatic activities of 5α-reductase using testosterone radioactively labeled with tritium. (authors)

  3. Phenylpropanoid Glycoside Analogues: Enzymatic Synthesis, Antioxidant Activity and Theoretical Study of Their Free Radical Scavenger Mechanism

    Science.gov (United States)

    López-Munguía, Agustín; Hernández-Romero, Yanet; Pedraza-Chaverri, José; Miranda-Molina, Alfonso; Regla, Ignacio; Martínez, Ana; Castillo, Edmundo

    2011-01-01

    Phenylpropanoid glycosides (PPGs) are natural compounds present in several medicinal plants that have high antioxidant power and diverse biological activities. Because of their low content in plants (less than 5% w/w), several chemical synthetic routes to produce PPGs have been developed, but their synthesis is a time consuming process and the achieved yields are often low. In this study, an alternative and efficient two-step biosynthetic route to obtain natural PPG analogues is reported for the first time. Two galactosides were initially synthesized from vanillyl alcohol and homovanillyl alcohol by a transgalactosylation reaction catalyzed by Kluyveromyces lactis β-galactosidase in saturated lactose solutions with a 30%–35% yield. To synthesize PPGs, the galactoconjugates were esterified with saturated and unsaturated hydroxycinnamic acid derivatives using Candida antarctica Lipase B (CaL-B) as a biocatalyst with 40%–60% yields. The scavenging ability of the phenolic raw materials, intermediates and PPGs was evaluated by the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH•) method. It was found that the biosynthesized PPGs had higher scavenging abilities when compared to ascorbic acid, the reference compound, while their antioxidant activities were found similar to that of natural PPGs. Moreover, density functional theory (DFT) calculations were used to determine that the PPGs antioxidant mechanism proceeds through a sequential proton loss single electron transfer (SPLET). The enzymatic process reported in this study is an efficient and versatile route to obtain PPGs from different phenylpropanoid acids, sugars and phenolic alcohols. PMID:21674039

  4. Supplementing with non-glycoside hydrolase proteins enhances enzymatic deconstruction of plant biomass.

    Science.gov (United States)

    Su, Xiaoyun; Zhang, Jing; Mackie, Roderick I; Cann, Isaac K O

    2012-01-01

    The glycoside hydrolases (GH) of Caldicellulosiruptor bescii are thermophilic enzymes, and therefore they can hydrolyze plant cell wall polysaccharides at high temperatures. Analyses of two C. bescii glycoside hydrolases, CbCelA-TM1 and CbXyn10A with cellulase and endoxylanase activity, respectively, demonstrated that each enzyme is highly thermostable under static incubation at 70°C. Both enzymes, however, rapidly lost their enzymatic activities when incubated at 70°C with end-over-end shaking. Since crowding conditions, even at low protein concentrations, seem to influence enzymatic properties, three non-glycoside hydrolase proteins were tested for their capacity to stabilize the thermophilic proteins at high temperatures. The three proteins investigated were a small heat shock protein CbHsp18 from C. bescii, a histone MkHistone1 from Methanopyrus kandleri, and bovine RNase A, from a commercial source. Fascinatingly, each of these proteins increased the thermostability of the glycoside hydrolases at 70°C during end-over-end shaking incubation, and this property translated into increases in hydrolysis of several substrates including the bioenergy feedstock Miscanthus. Furthermore, MkHistone1 and RNase A also altered the initial products released from the cello-oligosaccharide cellopentaose during hydrolysis with the cellodextrinase CbCdx1A, which further demonstrated the capacity of the three non-GH proteins to influence hydrolysis of substrates by the thermophilic glycoside hydrolases. The non-GH proteins used in the present report were small proteins derived from each of the three lineages of life, and therefore expand the space from which different polypeptides can be tested for their influence on plant cell wall hydrolysis, a critical step in the emerging biofuel industry.

  5. Supplementing with non-glycoside hydrolase proteins enhances enzymatic deconstruction of plant biomass.

    Directory of Open Access Journals (Sweden)

    Xiaoyun Su

    Full Text Available The glycoside hydrolases (GH of Caldicellulosiruptor bescii are thermophilic enzymes, and therefore they can hydrolyze plant cell wall polysaccharides at high temperatures. Analyses of two C. bescii glycoside hydrolases, CbCelA-TM1 and CbXyn10A with cellulase and endoxylanase activity, respectively, demonstrated that each enzyme is highly thermostable under static incubation at 70°C. Both enzymes, however, rapidly lost their enzymatic activities when incubated at 70°C with end-over-end shaking. Since crowding conditions, even at low protein concentrations, seem to influence enzymatic properties, three non-glycoside hydrolase proteins were tested for their capacity to stabilize the thermophilic proteins at high temperatures. The three proteins investigated were a small heat shock protein CbHsp18 from C. bescii, a histone MkHistone1 from Methanopyrus kandleri, and bovine RNase A, from a commercial source. Fascinatingly, each of these proteins increased the thermostability of the glycoside hydrolases at 70°C during end-over-end shaking incubation, and this property translated into increases in hydrolysis of several substrates including the bioenergy feedstock Miscanthus. Furthermore, MkHistone1 and RNase A also altered the initial products released from the cello-oligosaccharide cellopentaose during hydrolysis with the cellodextrinase CbCdx1A, which further demonstrated the capacity of the three non-GH proteins to influence hydrolysis of substrates by the thermophilic glycoside hydrolases. The non-GH proteins used in the present report were small proteins derived from each of the three lineages of life, and therefore expand the space from which different polypeptides can be tested for their influence on plant cell wall hydrolysis, a critical step in the emerging biofuel industry.

  6. Cryptococcus gattii urease as a virulence factor and the relevance of enzymatic activity in cryptococcosis pathogenesis.

    Science.gov (United States)

    Feder, Vanessa; Kmetzsch, Lívia; Staats, Charley Christian; Vidal-Figueiredo, Natalia; Ligabue-Braun, Rodrigo; Carlini, Célia Regina; Vainstein, Marilene Henning

    2015-04-01

    Ureases (EC 3.5.1.5) are Ni(2+) -dependent metalloenzymes produced by plants, fungi and bacteria that hydrolyze urea to produce ammonia and CO2 . The insertion of nickel atoms into the apo-urease is better characterized in bacteria, and requires at least three accessory proteins: UreD, UreF, and UreG. Our group has demonstrated that ureases possess ureolytic activity-independent biological properties that could contribute to the pathogenicity of urease-producing microorganisms. The presence of urease in pathogenic bacteria strongly correlates with pathogenesis in some human diseases. Some medically important fungi also produce urease, including Cryptococcus neoformans and Cryptococcus gattii. C. gattii is an etiological agent of cryptococcosis, most often affecting immunocompetent individuals. The cryptococcal urease might play an important role in pathogenesis. It has been proposed that ammonia produced via urease action might damage the host endothelium, which would enable yeast transmigration towards the central nervous system. To analyze the role of urease as a virulence factor in C. gattii, we constructed knockout mutants for the structural urease-coding gene URE1 and for genes that code the accessory proteins Ure4 and Ure6. All knockout mutants showed reduced multiplication within macrophages. In intranasally infected mice, the ure1Δ (lacking urease protein) and ure4Δ (enzymatically inactive apo-urease) mutants caused reduced blood burdens and a delayed time of death, whereas the ure6Δ (enzymatically inactive apo-urease) mutant showed time and dose dependency with regard to fungal burden. Our results suggest that C. gattii urease plays an important role in virulence, in part possibly through enzyme activity-independent mechanism(s). © 2015 FEBS.

  7. Enzymatic properties and localization of motopsin (PRSS12), a protease whose absence causes mental retardation.

    Science.gov (United States)

    Mitsui, Shinichi; Yamaguchi, Nozomi; Osako, Yoji; Yuri, Kazunari

    2007-03-09

    Motopsin (PRSS12) is a mosaic protease expressed in the central nervous system. Truncation of the human motopsin gene causes nonsyndromic mental retardation. Understanding the enzymatic properties and localization of motopsin protein in the central nervous system will help identify the molecular mechanism by which the loss of motopsin function causes mental retardation. Recombinant motopsin showed amidolytic activity against the synthetic substrate benzyloxycarbonyl-l-phenylalanyl-l-arginine 4-methyl-coumaryl-7-amide. Motopsin activated the single-chain tissue plasminogen activator precursor and exhibited gelatinolytic activity. This enzymatic activity was inhibited by typical serine protease inhibitors such as aprotinin, leupeptin, and (4-amidinophenyl) methanesulfonyl fluoride. Immunocytochemistry using anti-motopsin IgG revealed that both human and mouse motopsin proteins were distributed in discrete puncta along the dendrites and soma as well as axons in cultured hippocampal neurons. In the limbic system, including the cingulate and hippocampal pyramidal neurons and piriform cortex, high level of motopsin protein was expressed at postnatal day 10, but a very low level at 10-week-old mice. Motopsin and tissue plasminogen activator were co-expressed in the cingulate pyramidal neurons at postnatal day 10 and were distributed along dendrites of cultured pyramidal neurons. In cranial nuclei, a moderate level of motopsin protein was detected independently on the developmental stage. Our results suggest that motopsin has multiple functions, such as axon outgrowth, arranging perineuronal environment, and maintaining neuronal plasticity, partly in coordination with other proteases including tissue plasminogen activator.

  8. Cassava Pulp as a Biofuel Feedstock of an Enzymatic Hydrolysis Proces

    Directory of Open Access Journals (Sweden)

    Djuma’ali Djuma’ali

    2013-03-01

    Full Text Available Cassava pulp, a low cost solid byproduct of cassava starch industry, has been proposed as a high potential ethanolic fermentation substrate due to its high residual starch level, low ash content and small particle size of the lignocellulosic fibers. As the economic feasibility depends on complete degradation of the polysaccharides to fermentable glucose, the comparative hydrolytic potential of cassava pulp by six commercial enzymes were studied. Raw cassava pulp (12% w/v, particle size <320 μm hydrolyzed by both commercial pectinolytic (1 and amylolytic (2 enzymes cocktail, yielded 70.06% DE. Hydrothermal treatment of cassava pulp enhanced its susceptibility to enzymatic cleavageas compared to non-hydrothermal treatment raw cassava pulp. Hydrothermal pretreatment has shown that a glucoamylase (3 was the most effective enzyme for hydrolysis process of cassava pulp at temperature 65 °C or 95 °C for 10 min and yielded approximately 86.22% and 90.18% DE, respectively. Enzymatic pretreatment increased cassava pulp vulnerability to cellulase attacks. The optimum conditions for enzymatic pretreatment of 30% (w/v cassava pulp by a potent cellulolytic/ hemicellulolytic enzyme (4 was achieves at 50 °C for 3, meanwhile for liquefaction and saccharification by a thermo-stable α-amylase (5 was achieved at 95 °C for 1 and a glucoamylase (3 at 50 °C for 24 hours, respectively, yielded a reducing sugar level up to 94,1% DE. The high yield of glucose indicates the potential use of enzymatic-hydrothermally treated cassava pulp as a cheap substrate for ethanol production.

  9. Enzymatically active 2',5'-oligoadenylate synthetases are widely distributed among Metazoa, including protostome lineage.

    Science.gov (United States)

    Päri, Mailis; Kuusksalu, Anne; Lopp, Annika; Kjaer, Karina Hansen; Justesen, Just; Kelve, Merike

    2014-02-01

    2',5'-Oligoadenylate synthetases (OASs) belong to the nucleotidyl transferase family together with poly(A) polymerases, CCA-adding enzymes and the recently discovered cyclic-GMP-AMP synthase (cGAS). Mammalian OASs have been thoroughly characterized as components of the interferon-induced antiviral system. The OAS activity and the respective genes were also discovered in marine sponges where the interferon system is absent. In this study the recombinant OASs from several multicellular animals and their closest unicellular relative, a choanoflagellate, were expressed in a bacterial expression system and their enzymatic activities were examined. We demonstrated 2-5A synthesizing activities of OASs from the marine sponge Tedania ignis, a representative of the phylogenetically oldest metazoan phylum (Porifera), from an invertebrate of the protostome lineage, the mollusk Mytilus californianus (Mollusca), and from a vertebrate species, a cartilaginous fish Leucoraja erinacea (Chordata). However, the expressed proteins from an amphibian, the salamander Ambystoma mexicanum (Chordata), and from a protozoan, the marine choanoflagellate Monosiga brevicollis (Choanozoa), did not show 2-5A synthesizing activity. Differently from other studied OASs, OAS from the marine sponge T. ignis was able to catalyze the formation of oligomers having both 2',5'- and 3',5'-phosphodiester linkages. Our data suggest that OASs from sponges and evolutionarily higher animals have similar activation mechanisms which still include different affinities and possibly different structural requirements for the activating RNAs. Considering their 2'- and 3'-specificities, sponge OASs could represent a link between evolutionarily earlier nucleotidyl transferases and 2'-specific OASs from higher animals. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  10. High-yield production of pure tagatose from fructose by a three-step enzymatic cascade reaction.

    Science.gov (United States)

    Lee, Seon-Hwa; Hong, Seung-Hye; Kim, Kyoung-Rok; Oh, Deok-Kun

    2017-08-01

    To produce tagatose from fructose with a high conversion rate and to establish a high-yield purification method of tagatose from the reaction mixture. Fructose at 1 M (180 g l -1 ) was converted to 0.8 M (144 g l -1 ) tagatose by a three-step enzymatic cascade reaction, involving hexokinase, plus ATP, fructose-1,6-biphosphate aldolase, phytase, over 16 h with a productivity of 9 g l -1 h -1 . No byproducts were detected. Tagatose was recrystallized from ethanol to a purity of 99.9% and a yield of 96.3%. Overall, tagatose at 99.9% purity was obtained from fructose with a yield of 77%. This is the first biotechnological production of tagatose from fructose and the first application of solvent recrystallization for the purification of rare sugars.

  11. Metabolic activation of pyrrolizidine alkaloids: insights into the structural and enzymatic basis.

    Science.gov (United States)

    Ruan, Jianqing; Yang, Mengbi; Fu, Peter; Ye, Yang; Lin, Ge

    2014-06-16

    Pyrrolizidine alkaloids (PAs) are natural toxins widely distributed in plants. The toxic potencies of different PAs vary significantly. PAs are mono- or diesters of necine acids with a necine base. On the basis of the necine bases, PAs are classified into three types: retronecine-type, otonecine-type, and platynecine-type. Hepatotoxic PAs contain an unsaturated necine base. PAs exert hepatotoxicity through metabolic activation by hepatic cytochromes P450s (CYPs) to generate reactive intermediates which form pyrrole-protein adducts. These adducts provide a mechanism-based biomarker to assess PA toxicity. In the present study, metabolic activation of 12 PAs from three structural types was investigated first in mice to demonstrate significant variations in hepatic metabolic activation of different PAs. Subsequently, the structural and enzymatic factors affecting metabolic activation of these PAs were further investigated by using human liver microsomes and recombinant human CYPs. Pyrrole-protein adducts were detected in the liver and blood of mice and the in vitro systems treated with toxic retronecine-type and otonecine-type PAs having unsaturated necine bases but not with a platynecine-type PA containing a saturated necine base. Retronecine-type PAs produced more pyrrole-protein adducts than otonecine-type PAs with similar necine acids, demonstrating that the structure of necine base affected PA toxic potency. Among retronecine-type PAs, open-ring diesters generated the highest amount of pyrrole-protein adducts, followed by macrocyclic diesters, while monoesters produced the least. Only CYP3A4 and CYP3A5 activated otonecine-type PAs, while all 10 CYPs studied showed the ability to activate retronecine-type PAs. Moreover, the contribution of major CYPs involved also varied significantly among retronecine-type PAs. In conclusion, our findings provide a scientific basis for predicting the toxicities of individual PAs in biological systems based on PA structural

  12. Perspectives for the industrial enzymatic production of glycosides.

    Science.gov (United States)

    de Roode, B Mattheus; Franssen, Maurice C R; van der Padt, Albert; Boom, Remko M

    2003-01-01

    Glycosides are of commercial interest for industry in general and specifically for the pharmaceutical and food industry. Currently chemical preparation of glycosides will not meet EC food regulations, and therefore chemical preparation of glycosides is not applicable in the food industry. Thus, enzyme-catalyzed reactions are a good alternative. However, until now the low yields obtained by enzymatic methods prevent the production of glycosides on a commercial scale. Therefore, high yields should be established by a combination of optimum reaction conditions and continuous removal of the product. Unfortunately, a bioreactor for the commercial scale production of glycosides is not available. The aim of this article is to discuss the literature with respect to enzymatic production of glycosides and the design of an industrially viable bioreactor system.

  13. Improving biogas production from microalgae by enzymatic pretreatment.

    Science.gov (United States)

    Passos, Fabiana; Hom-Diaz, Andrea; Blanquez, Paqui; Vicent, Teresa; Ferrer, Ivet

    2016-01-01

    In this study, enzymatic pretreatment of microalgal biomass was investigated under different conditions and evaluated using biochemical methane potential (BMP) tests. Cellulase, glucohydrolase and an enzyme mix composed of cellulase, glucohydrolase and xylanase were selected based on the microalgae cell wall composition (cellulose, hemicellulose, pectin and glycoprotein). All of them increased organic matter solubilisation, obtaining high values already after 6h of pretreatment with an enzyme dose of 1% for cellulase and the enzyme mix. BMP tests with pretreated microalgae showed a methane yield increase of 8 and 15% for cellulase and the enzyme mix, respectively. Prospective research should evaluate enzymatic pretreatments in continuous anaerobic reactors so as to estimate the energy balance and economic cost of the process. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. ETHANOL ORGANOSOLV PRETREATMENT OF BAMBOO FOR EFFICIENT ENZYMATIC SACCHARIFICATION

    Directory of Open Access Journals (Sweden)

    Zhiqiang Li,

    2012-06-01

    Full Text Available Bamboo is a potential lignocellulosic biomass for the production of bioethanol because of its high cellulose and hemicelluloses content. In this research, ethanol organosolv pretreatment with dilute sulfuric acid as the catalyst was studied in order to enhance enzymatic saccharification of moso bamboo. The addition of 2% (w/w bamboo dilute sulfuric acid in 75% ethanol had a particularly strong effect on fractionation of bamboo. It yielded a solids fraction containing 83.4% cellulose in the treated substrate. The cellulose conversion to glucose yield reached 77.1 to 83.4% after enzymatic hydrolysis of the solids fraction for 48 h at an enzyme loading of 15 FPU cellulase/g cellulose and 30 IU β-glucosidase/g cellulose. The enzymatic hydrolysis rate was significantly accelerated as the ethanol organosolv pretreatment time increased, reaching the highest enzymatic glucose yield of 83.4% after 48 h at 50 °C. The concentrations of fermentation inhibitors such as HMF (5-hydroxy-2-methyl furfural and furfural were 0.96 g/L and 4.38 g/L in the spent liquor after the ethanol organosolv pretreatment, which were slightly lower than the concentrations quantified during H2SO4-water treatment. Spent liquor was diluted with water, and more than 87.2% of lignin in raw bamboo was recovered as ethanol organosolv lignin through the filtration process.

  15. Modification of chemical properties, Cu fractionation and enzymatic activities in an acid vineyard soil amended with winery wastes: A field study.

    Science.gov (United States)

    Rodríguez-Salgado, Isabel; Pérez-Rodríguez, Paula; Gómez-Armesto, Antía; Díaz-Raviña, Montserrat; Nóvoa-Muñoz, Juan Carlos; Arias-Estévez, Manuel; Fernández-Calviño, David

    2017-11-01

    The effects of adding two winery wastes, perlite waste (PW) and bentonite waste (BW), to an acid vineyard soil were assessed using some chemical and biological soil properties in a field study that lasted 18 months. The addition of PW (up to 81 Mg ha -1 ) had neither significant nor permanent effects on soil characteristics such as the pH, organic matter content or nutrient concentrations, the amounts of copper or zinc, or the electrical conductivity. Moreover, no persistent negative effects were found on the enzymatic activities after PW application. In contrast, soil that was amended with up to 71 Mg BW ha -1 showed increases in its soil pH values, exchangeable potassium and water soluble potassium and phosphorus contents. In addition, it caused significant increases in the electrical conductivity and water-soluble Cu. In addition, the phosphomonoesterase enzymatic activity decreased significantly (up to 28%) in response to the amendment with 71 Mg BW ha -1 . These results showed that adding BW and PW to the soil may be a good agronomic practice for recycling these types of wastes. However, in the case of PW, its use as a soil amendment must be performed with caution to control its possible harmful effects. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Dual role of the carboxyl-terminal region of pig liver L-kynurenine 3-monooxygenase: mitochondrial-targeting signal and enzymatic activity.

    Science.gov (United States)

    Hirai, Kumiko; Kuroyanagi, Hidehito; Tatebayashi, Yoshitaka; Hayashi, Yoshitaka; Hirabayashi-Takahashi, Kanako; Saito, Kuniaki; Haga, Seiich; Uemura, Tomihiko; Izumi, Susumu

    2010-12-01

    l-kynurenine 3-monooxygenase (KMO) is an NAD(P)H-dependent flavin monooxygenase that catalyses the hydroxylation of l-kynurenine to 3-hydroxykynurenine, and is localized as an oligomer in the mitochondrial outer membrane. In the human brain, KMO may play an important role in the formation of two neurotoxins, 3-hydroxykynurenine and quinolinic acid, both of which provoke severe neurodegenerative diseases. In mosquitos, it plays a role in the formation both of eye pigment and of an exflagellation-inducing factor (xanthurenic acid). Here, we present evidence that the C-terminal region of pig liver KMO plays a dual role. First, it is required for the enzymatic activity. Second, it functions as a mitochondrial targeting signal as seen in monoamine oxidase B (MAO B) or outer membrane cytochrome b(5). The first role was shown by the comparison of the enzymatic activity of two mutants (C-terminally FLAG-tagged KMO and carboxyl-terminal truncation form, KMOΔC50) with that of the wild-type enzyme expressed in COS-7 cells. The second role was demonstrated with fluorescence microscopy by the comparison of the intracellular localization of the wild-type, three carboxyl-terminal truncated forms (ΔC20, ΔC30 and ΔC50), C-terminally FLAG-tagged wild-type and a mutant KMO, where two arginine residues, Arg461-Arg462, were replaced with Ser residues.

  17. MnO{sub x}/C nanocomposite: An insight on high-performance supercapacitor and non-enzymatic hydrogen peroxide detection

    Energy Technology Data Exchange (ETDEWEB)

    Ahuja, Preety, E-mail: drpreetyahuja@gmail.com [Department of Chemistry, Jamia Hamdard, Delhi 110062 (India); Kumar Ujjain, Sanjeev [Department of Physics, Indian Institute of Technology, Kanpur, UP 208016 (India); Kanojia, Rajni [Department of Chemistry, Shivaji College, University of Delhi, Delhi 110027 (India)

    2017-05-15

    Graphical abstract: In-situ inclusion of carbon matrix during growth of MnO{sub x} nanoparticles resulted in MnO{sub x}/C nanocomposite with enhanced electronic diffusion leading to high energy/power densities supercapacitor and highly sensitive H{sub 2}O{sub 2} sensor. - Highlights: • MnO{sub x}/C, synthesized via microemulsion method, is electrochemically investigated towards supercapacitor and sensing applications. • In-situ inclusion of conducting carbon in manganese oxide enhances the network conductivity facilitating the charge transfer process. • It provides high energy and power density, 31.6 Wh kg{sup −1} and 3.8 kW kg{sup −1} respectively, with short relaxation time ∼3 ms for fabricated cell. • MnO{sub x}/C as sensor, exhibits excellent catalytic activity toward H{sub 2}O{sub 2} oxidation and offer high sensitivity with low detection limit. - Abstract: In this work, we have used microemulsion method for synthesis of MnO{sub x}/C nanocomposite and investigated its electrochemical properties via fabrication of supercapacitor and non-enzymatic hydrogen peroxide (H{sub 2}O{sub 2}) sensor. In-situ inclusion of conducting carbon in manganese oxide (MnO{sub x}/C) enhances the network conductivity facilitating the charge transfer process which is beneficial for supercapacitor and sensing applications. MnO{sub x}/C provides high energy and power density, 31.6 Wh kg{sup −1} and 3.8 kW kg{sup −1} respectively and short relaxation time ∼3 ms for fabricated cell (MnO{sub x}/C//MnO{sub x}/C) endowing excellent power delivery capacity. Furthermore, MnO{sub x}/C as sensor, exhibits excellent catalytic activity toward the oxidation of H{sub 2}O{sub 2} and shows high sensitivity (0.37 mA mM{sup −1} cm{sup −2}) with low detection limit (0.5 μM at an S/N of 3). Hence, this study provides new avenue for high performance supercapacitor and H{sub 2}O{sub 2} detection.

  18. STUDY OF THE PREPARATION OF SUGAR FROM HIGH-LIGNIN LIGNOCELLULOSE APPLYING SUBCRITICAL WATER AND ENZYMATIC HYDROLYSIS: SYNTHESIS AND CONSUMABLE COST EVALUATION

    Directory of Open Access Journals (Sweden)

    HANNY F. SANGIAN

    2015-05-01

    Full Text Available This study concern sugars hydrolyzed from the high-lignin coconut coir dust using moderate subcritical water (SCW hydrolysis at pressures 20-40 bar for 1 h and to evaluate the consumable costs driver generated. The SCW method produced two products, sugar liquid and solid (SCW-treated substrate. The solid was proceeded to prepare the sugar via enzymatic hydrolysis using pure cellulase. Yield of sugar hydrolyzed from lignocellulose by SCW technique was 0.25 gram sugar/gram cellulose +hemicellulose, or 0.09-gram sugar/gram lignocellulose at 160 °C and 40 bar. While, the maximum yield of sugar liberated enzymatically from SCW-treated solid was 0.35-gram sugar/gram cellulose+hemicellulose, or 0.13-gram sugar/gram SCW-treated solid. It was found that carbon dioxide gas was the highest cost driving in SCW hydrolysis.

  19. Steam explosion pretreatment of softwood: the effect of the explosive decompression on enzymatic digestibility.

    Science.gov (United States)

    Pielhop, Thomas; Amgarten, Janick; von Rohr, Philipp Rudolf; Studer, Michael H

    2016-01-01

    Steam explosion pretreatment has been examined in many studies for enhancing the enzymatic digestibility of lignocellulosic biomass and is currently the most common pretreatment method in commercial biorefineries. The information available about the effect of the explosive decompression on the biochemical conversion is, however, very limited, and no studies prove that the latter is actually enhanced by the explosion. Hence, it is of great value to discern between the effect of the explosion on the one hand and the steaming on the other hand, to identify their particular influences on enzymatic digestibility. The effect of the explosive decompression in the steam explosion pretreatment of spruce wood chips on their enzymatic cellulose digestibility was studied systematically. The explosion had a high influence on digestibility, improving it by up to 90 % compared to a steam pretreatment without explosion. Two factors were identified to be essentially responsible for the effect of the explosion on enzymatic digestibility: pretreatment severity and pressure difference of the explosion. A higher pretreatment severity can soften up and weaken the lignocellulose structure more, so that the explosion can better break up the biomass and decrease its particle size, which enhances its digestibility. In particular, increasing the pressure difference of the explosion leads to more defibration, a smaller particle size and a better digestibility. Though differences were found in the micro- and nanostructure of exploded and non-exploded biomass, the only influence of the explosion on digestibility was found to be the macroscopic particle size reduction. Steam explosion treatments with a high severity and a high pressure difference of the explosion lead to a comparatively high cellulose digestibility of the-typically very recalcitrant-softwood biomass. This is the first study to show that explosion can enhance the enzymatic digestibility of lignocellulosic biomass. If the

  20. Non-Enzymatic Wearable Sensor for Electrochemical Analysis of Perspiration Glucose.

    Science.gov (United States)

    Zhu, Xiaofei; Ju, Yinhui; Chen, Jian; Liu, Deye; Liu, Hong

    2018-05-16

    We report a non-enzymatic wearable sensor for electrochemical analysis of perspiration glucose. Multi-potential steps are applied on a Au electrode, including a high negative pretreatment potential step for proton reduction which produc-es a localized alkaline condition, a moderate potential step for electrocatalytic oxidation of glucose under the alkaline condi-tion, and a positive potential step to clean and reactivate the electrode surface for the next detection. Fluorocarbon-based materials were coated on the Au electrode for improving the selectivity and robustness of the sensor. A fully integrated wrist-band is developed for continuous real-time monitoring of perspiration glucose during physical activities, and uploading the test result to a Smartphone App via Bluetooth.

  1. Anti-oxidant, anti-inflammatory and immunomodulating properties of an enzymatic protein hydrolysate from yellow field pea seeds.

    Science.gov (United States)

    Ndiaye, Fatou; Vuong, Tri; Duarte, Jairo; Aluko, Rotimi E; Matar, Chantal

    2012-02-01

    Enzymatic protein hydrolysates of yellow pea seed have been shown to possess high anti-oxidant and anti-bacterial activities. The aim of this work was to confirm the anti-oxidant, anti-inflammatory and immunomodulating activities of an enzymatic protein hydrolysate of yellow field pea seeds. The anti-oxidant and anti-inflammatory properties of peptides from yellow field pea proteins (Pisum sativum L.) were investigated in LPS/IFN-γ-activated RAW 264.7 NO⁻ macrophages. The immunomodulating potential of pea protein hydrolysate (PPH) was then studied in a murine model. Pea protein hydrolysate, after a 12 h pre-treatment, showed significant inhibition of NO production by activated macrophages up to 20%. Moreover, PPH significantly inhibited their secretion of pro-inflammatory cytokines, TNF-α- and IL-6, up to 35 and 80%, respectively. Oral administration of PPH in mice enhanced the phagocytic activity of their peritoneal macrophages and stimulated the gut mucosa immune response. The number of IgA+ cells was elevated in the small intestine lamina propria, accompanied by an increase in the number of IL-4+, IL-10+ and IFN-γ+ cells. This was correlated to up-regulation of IL-6 secretion by small intestine epithelial cells (IEC), probably responsible for B-cell terminal differentiation to IgA-secreting cells. Moreover, PPH might have increased IL-6 production in IECs via the stimulation of toll-like receptors (TLRs) family, especially TLR2 and TLR4 since either anti-TLR2 or anti-TLR4 was able to completely abolish PPH-induced IL-6 secretion. Enzymatic protein degradation confers anti-oxidant, anti-inflammatory and immunomodulating potentials to pea proteins, and the resulted peptides could be used as an alternative therapy for the prevention of inflammatory-related diseases.

  2. New and highly sensitive assay for L-5-hydroxytryptophan decarboxylase activity by high-performance liquid chromatography-voltammetry.

    Science.gov (United States)

    Rahman, M K; Nagatsu, T; Kato, T

    1980-12-12

    This paper describes a new, inexpensive and highly sensitive assay for aromatic L-amino acid decarboxylase (AADC) activity, using L-5-hydroxytryptophan (L-5-HTP) as substrate, in rat and human brains and serum by high-performance liquid chromatography (HPLC) with voltammetric detection. L-5-HTP was used as substrate and D-5-HTP for the blank. After isolating serotonin (5-HT) formed enzymatically from L-5-HTP on a small Amberlite CG-50 column, the 5-HT was eluted with hydrochloric acid and assayed by HPLC with a voltammetric detector. N-Methyldopamine was added to each incubation mixture as an internal standard. This method is sensitive enough to measure 5-HT, formed by the enzyme, 100 fmol to 140 pmol or more. An advantage of this method is that one can incubate the enzyme for longer time (up to 150 min), as compared with AADC assay using L-DOPA as substrate, resulting in a very high sensitivity. By using this new method, AADC activity was discovered in rat serum.

  3. Enzymatic Hydrolysis of Pretreated Fibre Pressed Oil Palm Frond by using Sacchariseb C6

    Science.gov (United States)

    Hashim, F. S.; Yussof, H. W.; Zahari, M. A. K. M.; Rahman, R. A.; Illias, R. M.

    2017-06-01

    Enzymatic hydrolysis becomes a prominent technology for conversion of cellulosic biomass to its glucose monomers that requires an action of cellulolytic enzymes in a sequential and synergistic manner. In this study, the effect of agitation speed, glucan loading, enzyme loading, temperature and reaction time on the production of glucose from fibre pressed oil palm frond (FPOPF) during enzymatic hydrolysis was screened by a half factorial design 25-1 using Response Surface Methodology (RSM). The FPOPF sample was first delignified by alkaline pretreatment at 4.42 (w/v) sodium hydroxide for an hour prior to enzymatic hydrolysis using commercial cellulase enzyme, Sacchariseb C6. The effect of enzymatic hydrolysis on the structural of FPOPF has been evaluated by Scanning Electron Microscopy (SEM) analysis. Characterization of raw FPOPF comprised of 4.5 extractives, 40.7 glucan, 26.1 xylan, 26.2 lignin and 1.8 ash, whereas for pretreated FPOPF gave 0.3 extractives, 61.4 glucan, 20.4 xylan, 13.3 lignin and 1.3 ash. From this study, it was found that the best enzymatic hydrolysis condition yielded 33.01 ± 0.73 g/L of glucose when performed at 200 rpm of agitation speed, 60 FPU/mL of enzyme loading, 4 (w/w) of glucan loading, temperature at 55 □ and 72 hours of reaction time. The model obtained was significant with p-value enzymatic hydrolysis from pretreated FPOPF produce high amount of glucose that enhances it potential for industrial application. This glucose can be further used to produce high-value products.

  4. Enzymatic hydrolysis of pretreated soybean straw

    International Nuclear Information System (INIS)

    Xu Zhong; Wang Qunhui; Jiang Zhaohua; Yang Xuexin; Ji Yongzhen

    2007-01-01

    In order to produce lactic acid, from agricultural residues such as soybean straw, which is a raw material for biodegradable plastic production, it is necessary to decompose the soybean straw into soluble sugars. Enzymatic hydrolysis is one of the methods in common use, while pretreatment is the effective way to increase the hydrolysis rate. The optimal conditions of pretreatment using ammonia and enzymatic hydrolysis of soybean straw were determined. Compared with the untreated straw, cellulose in straw pretreated by ammonia liquor (10%) soaking for 24 h at room temperature increased 70.27%, whereas hemicellulose and lignin in pretreated straw decreased to 41.45% and 30.16%, respectively. The results of infrared spectra (IR), scanning electron microscope (SEM) and X-ray diffraction (XRD) analysis also showed that the structure and the surface of the straw were changed through pretreatment that is in favor of the following enzymatic hydrolysis. maximum enzymatic hydrolysis rate of 51.22% was achieved at a substrate concentration of 5% (w/v) at 50 deg. C and pH 4.8 using cellulase (50 fpu/g of substrate) for 36 h

  5. Non-ionic Surfactants and Non-Catalytic Protein Treatment on Enzymatic Hydrolysis of Pretreated Creeping Wild Ryegrass

    Science.gov (United States)

    Zheng, Yi; Pan, Zhongli; Zhang, Ruihong; Wang, Donghai; Jenkins, Bryan

    Our previous research has shown that saline Creeping Wild Ryegrass (CWR), Leymus triticoides, has a great potential to be used for bioethanol production because of its high fermentable sugar yield, up to 85% cellulose conversion of pretreated CWR. However, the high cost of enzyme is still one of the obstacles making large-scale lignocellulosic bioethanol production economically difficult. It is desirable to use reduced enzyme loading to produce fermentable sugars with high yield and low cost. To reduce the enzyme loading, the effect of addition of non-ionic surfactants and non-catalytic protein on the enzymatic hydrolysis of pretreated CWR was investigated in this study. Tween 20, Tween 80, and bovine serum albumin (BSA) were used as additives to improve the enzymatic hydrolysis of dilute sulfuric-acid-pretreated CWR. Under the loading of 0.1 g additives/g dry solid, Tween 20 was the most effective additive, followed by Tween 80 and BSA. With the addition of Tween 20 mixed with cellulase loading of 15 FPU/g cellulose, the cellulose conversion increased 14% (from 75 to 89%), which was similar to that with cellulase loading of 30 FPU/g cellulose and without additive addition. The results of cellulase and BSA adsorption on the Avicel PH101, pretreated CWR, and lignaceous residue of pretreated CWR support the theory that the primary mechanism behind the additives is prevention of non-productive adsorption of enzymes on lignaceous material of pretreated CWR. The addition of additives could be a promising technology to improve the enzymatic hydrolysis by reducing the enzyme activity loss caused by non-productive adsorption.

  6. Regenerative, Highly-Sensitive, Non-Enzymatic Dopamine Sensor and Impact of Different Buffer Systems in Dopamine Sensing

    Directory of Open Access Journals (Sweden)

    Saumya Joshi

    2018-01-01

    Full Text Available Carbon nanotube field-effect transistors are used extensively in ultra-sensitive biomolecule sensing applications. Along with high sensitivity, the possibility of regeneration is highly desired in bio-sensors. An important constituent of such bio-sensing systems is the buffer used to maintain pH and provide an ionic conducting medium, among its other properties. In this work, we demonstrate highly-sensitive regenerative dopamine sensors and the impact of varying buffer composition and type on the electrolyte gated field effect sensors. The role of the buffer system is an often ignored condition in the electrical characterization of sensors. Non-enzymatic dopamine sensors are fabricated and regenerated in hydrochloric acid (HCl solution. The sensors are finally measured against four different buffer solutions. The impact of the nature and chemical structure of buffer molecules on the dopamine sensors is shown, and the appropriate buffer systems are demonstrated.

  7. Enzymatic approaches to rare sugar production.

    Science.gov (United States)

    Zhang, Wenli; Zhang, Tao; Jiang, Bo; Mu, Wanmeng

    Rare sugars have recently attracted much attention because of their potential applications in the food, nutraceutical, and pharmaceutical industries. A systematic strategy for enzymatic production of rare sugars, named Izumoring, was developed >10years ago. The strategy consists of aldose-ketose isomerization, ketose C-3 epimerization, and monosaccharide oxidation-reduction. Recent development of the Izumoring strategy is reviewed herein, especially the genetic approaches to the improvement of rare sugar-producing enzymes and the applications of target-oriented bioconversion. In addition, novel non-Izumoring enzymatic approaches are also summarized, including enzymatic condensation, phosphorylation-dephosphorylation cascade reaction, aldose epimerization, ulosonic acid decarboxylation, and biosynthesis of rare disaccharides. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Effect of Enzymatic Hydrolysis on the Antioxidant Properties of Alcoholic Extracts of Oilseed Cakes

    Directory of Open Access Journals (Sweden)

    Jacek Arct

    2013-01-01

    Full Text Available The aim of the present study is to compare changes in the total phenolic, flavonoid and reducing sugar content and antioxidant activity of alcoholic extracts of Oenothera biennis, Borago officinalis and Nigella sativa oilseed cakes before and after enzymatic hydrolysis. Extraction with ethanol and hydrolysis with different commercially available glycosidases: α-amylase, β-glucosidase, β-glucanase and their combinations in a ratio of 1:1:1 were investigated. Total phenolic, flavonoid and reducing sugar content, iron-chelating activity and antioxidant activity according to DPPH and ABTS tests were measured in non-hydrolysed extracts and compared with the results obtained for the extracts after the application of immobilised enzymes. As a result, the hydrolysed extracts had a higher phenolic and reducing sugar content as well as higher iron-chelating and antioxidant activities. Total phenolic content of Oenothera biennis, Borago officinalis and Nigella sativa oilseed cake extracts after enzymatic hydrolysis was higher in comparison with non-hydrolysed extracts, i.e. 2 times (for the enzyme combination, and 1.5 and 2 times (for β-glucanase (p<0.05, respectively. The best results in increasing the flavonoid and sugar content as well as in iron-chelating activity were obtained after enzymatic hydrolysis of oilseed cake extracts by β-glucanase. Oilseed cake extracts after hydrolysis with an enzyme combination in a ratio of 1:1:1 had the highest increase in antioxidant activity.

  9. DOTA-functionalized polylysine: a high number of DOTA chelates positively influences the biodistribution of enzymatic conjugated anti-tumor antibody chCE7agl.

    Science.gov (United States)

    Grünberg, Jürgen; Jeger, Simone; Sarko, Dikran; Dennler, Patrick; Zimmermann, Kurt; Mier, Walter; Schibli, Roger

    2013-01-01

    Site-specific enzymatic reactions with microbial transglutaminase (mTGase) lead to a homogenous species of immunoconjugates with a defined ligand/antibody ratio. In the present study, we have investigated the influence of different numbers of 1,4,7,10-tetraazacyclododecane-N-N'-N''-N'''-tetraacetic acid (DOTA) chelats coupled to a decalysine backbone on the in vivo behavior of the chimeric monoclonal anti-L1CAM antibody chCE7agl. The enzymatic conjugation of (DOTA)1-decalysine, (DOTA)3-decalysine or (DOTA)5-decalysine to the antibody heavy chain (via Gln295/297) gave rise to immunoconjugates containing two, six or ten DOTA moieties respectively. Radiolabeling of the immunoconjugates with (177)Lu yielded specific activities of approximately 70 MBq/mg, 400 MBq/mg and 700 MBq/mg with increasing numbers of DOTA chelates. Biodistribution experiments in SKOV3ip human ovarian cancer cell xenografts demonstrated a high and specific accumulation of radioactivity at the tumor site for all antibody derivatives with a maximal tumor accumulation of 43.6±4.3% ID/g at 24 h for chCE7agl-[(DOTA)-decalysine]2, 30.6±12.0% ID/g at 24 h for chCE7agl-[(DOTA)3-decalysine]2 and 49.9±3.1% ID/g at 48 h for chCE7agl-[(DOTA)5-decalysine)]2. The rapid elimination from the blood of chCE7agl-[(DOTA)-decalysine]2 (1.0±0.1% ID/g at 24 h) is associated with a high liver accumulation (23.2±4.6% ID/g at 24 h). This behavior changed depending on the numbers of DOTA moieties coupled to the decalysine peptide with a slower blood clearance (5.1±1.0 (DOTA)3 versus 11.7±1.4% ID/g (DOTA)5, pDOTA)3 versus 5.8±0.7 (DOTA)5, pDOTA-substituted decalysine ((DOTA)5-decalysine) to an anti-tumor antibody leads to the formation of immunoconjugates with high specific activity and excellent in vivo behavior and is a valuable option for radioimmunotherapy and potentially antibody-drug conjugates (ADCs).

  10. Evaluation of soluble fraction and enzymatic residual fraction of dilute dry acid, ethylenediamine, and steam explosion pretreated corn stover on the enzymatic hydrolysis of cellulose.

    Science.gov (United States)

    Qin, Lei; Liu, Li; Li, Wen-Chao; Zhu, Jia-Qing; Li, Bing-Zhi; Yuan, Ying-Jin

    2016-06-01

    This study is aimed to examine the inhibition of soluble fraction (SF) and enzymatic residual fraction (ERF) in dry dilute acid (DDA), ethylenediamine (EDA) and steam explosion (SE) pretreated corn stover (CS) on the enzymatic digestibility of cellulose. SF of DDA, EDA and SE pretreated CS has high xylose, soluble lignin and xylo-oligomer content, respectively. SF of EDA pretreated CS leads to the highest inhibition, followed by SE and DDA pretreated CS. Inhibition of ERF of DDA and SE pretreated CS is higher than that of EDA pretreated CS. The inhibition degree (A0/A) of SF is 1.76 and 1.21 times to that of ERF for EDA and SE pretreated CS, respectively. The inhibition degree of ERF is 1.05 times to that of SF in DDA pretreated CS. The quantitative analysis shows that SF of EDA pretreated CS, SF and ERF of SE pretreated CS cause significant inhibition during enzymatic hydrolysis. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Altered enzymatic activity and allele frequency of OMI/HTRA2 in Alzheimer's disease

    Science.gov (United States)

    Westerlund, Marie; Behbahani, Homira; Gellhaar, Sandra; Forsell, Charlotte; Belin, Andrea Carmine; Anvret, Anna; Zettergren, Anna; Nissbrandt, Hans; Lind, Charlotta; Sydow, Olof; Graff, Caroline; Olson, Lars; Ankarcrona, Maria; Galter, Dagmar

    2011-01-01

    The serine-protease OMI/HTRA2, required for several cellular processes, including mitochondrial function, autophagy, chaperone activity, and apoptosis, has been implicated in the pathogenesis of both Alzheimer's disease (AD) and Parkinson's disease (PD). Western blot quantification of OMI/HTRA2 in frontal cortex of patients with AD (n=10) and control subjects (n=10) in two separate materials indicated reduced processed (active, 35 kDa) OMI/HTRA2 levels, whereas unprocessed (50 kDa) enzyme levels were not significantly different between the groups. Interestingly, the specific protease activity of OMI/HTRA2 was found to be significantly increased in patients with AD (n=10) compared to matched control subjects (n=10) in frontal cortex in two separate materials. Comparison of OMI/HTRA2 mRNA levels in frontal cortex and hippocampus, two brain areas particularly affected by AD, indicated similar levels in patients with AD (n=10) and matched control subjects (n=10). In addition, we analyzed the occurrence of the OMI/HTRA2 variants A141S and G399S in Swedish case-control materials for AD and PD and found a weak association of A141S with AD, but not with PD. In conclusion, our genetic, histological, and biochemical findings give further support to an involvement of OMI/HTRA2 in the pathology of AD; however, further studies are needed to clarify the role of this gene in neurodegeneration.—Westerlund, M., Behbahani, H., Gellhaar, S., Forsell, C., Carmine Belin, A., Anvret, A., Zettergren, A., Nissbrandt, H., Lind, C., Sydow, O., Graff, C., Olson, L., Ankarcrona, M., Galter, D. Altered enzymatic activity and allele frequency of OMI/HTRA2 in Alzheimer's disease. PMID:21163861

  12. Inhibition of Enzymatic Browning of Chlorogenic Acid by Sulfur-Containing Compounds

    NARCIS (Netherlands)

    Kuijpers, T.F.M.; Narvaez Cuenca, C.E.; Vincken, J.P.; Verloop, J.W.; Berkel, van W.J.H.; Gruppen, H.

    2012-01-01

    The antibrowning activity of sodium hydrogen sulfite (NaHSO3) was compared to that of other sulfur-containing compounds. Inhibition of enzymatic browning was investigated using a model browning system consisting of mushroom tyrosinase and chlorogenic acid (5-CQA). Development of brown color

  13. Bioconversion and enzymatic activities of neurospora sitophila grown under solid state and submerged fermentation on Sago Hamps

    International Nuclear Information System (INIS)

    Shojaosadati, S. A.; Vikineswary, S.; Looi, C. C.

    2000-01-01

    N.Sitophila was grown under controlled conditions of solid state and submerged fermentation on Sago Hampas. The optimum conditions of protein enrichment previously established for sugar beet pulp was used for this study. Under this condition the protein content of Sago Hampas under solid state increased from 1.4 to 14.45% (W/W) whereas for Sago Hampas and Sago starch, the protein content under submerged condition increased from 1.4% (W/W) and 0.7% (W/W) to 18.56% (W/W) and 43/16% (W/W) based on dry weight of product respectively. The cellulase, a-amylase and glucoamylase activities of N.Sitophila under solid state condition on Sago Hampas were, 9.0, 0.6 and 11.8 U/g of wet fermented solid respectively. the enzymatic activities were also measured under submerged fermentation using both Sago Hampas and Sago starch as substrate

  14. Enzymatic Saccharification and Ethanol Fermentation of Reed Pretreated with Liquid Hot Water

    Directory of Open Access Journals (Sweden)

    Jie Lu

    2012-01-01

    Full Text Available Reed is a widespread-growing, inexpensive, and readily available lignocellulosic material source in northeast China. The objective of this study is to evaluate the liquid hot water (LHW pretreatment efficiency of reed based on the enzymatic digestibility and ethanol fermentability of water-insoluble solids (WISs from reed after the LHW pretreatment. Several variables in the LHW pretreatment and enzymatic hydrolysis process were optimized. The conversion of glucan to glucose and glucose concentrations are considered as response variables in different conditions. The optimum conditions for the LHW pretreatment of reed area temperature of 180°C for 20min and a solid-to-liquid ratio of 1 : 10. These optimum conditions for the LHW pretreatment of reed resulted in a cellulose conversion rate of 82.59% in the subsequent enzymatic hydrolysis at 50°C for 72 h with a cellulase loading of 30 filter paper unit per gram of oven-dried WIS. Increasing the pretreatment temperature resulted in a higher enzymatic digestibility of the WIS from reed. Separate hydrolysis and fermentation of WIS showed that the conversion of glucan to ethanol reached 99.5% of the theoretical yield. The LHW pretreatment of reed is a suitable method to acquire a high recovery of fermentable sugars and high ethanol conversion yield.

  15. Topical formulations with superoxide dismutase: influence of formulation composition on physical stability and enzymatic activity.

    Science.gov (United States)

    Di Mambro, Valéria M; Borin, Maria F; Fonseca, Maria J V

    2003-04-24

    Three different topical formulations were supplemented with superoxide dismutase (SOD) and evaluated concerning physical and chemical stabilities in order to determine the most stable formulation that would maintain SOD activity. Physical stability was evaluated by storing the formulation at room temperature, and at 37 and 45 degrees C for 28 days. Samples were collected at 7-day intervals for assessment of rheological behavior. Chemical stability was evaluated by the measurement of enzymatic activity in formulations stored at room temperature and at 45 degrees C for 75 days. The formulations showed a pseudoplastic behavior, with a flow index of less than 1. There was no significant difference in the initial values of flow index, hysteresis loop or minimum apparent viscosity. The simple emulsion and the one stabilized with hydroxyethylcellulose showed decreased viscosity by the 21st day and with higher temperature, but no significant changes concerning the presence of SOD. Although there were no significant changes concerning storage time or temperature, the formulation stabilized with hydroxyethylcellulose showed a marked loss of SOD activity. The addition of SOD to the formulations studied did not affect their physical stability. Simple emulsions or emulsions stabilized with carboxypolymethylene seem to be better bases for enzyme addition than emulsion stabilized with hydroxyethylcellulose.

  16. Enzymatic hydrolysis of biomimetic bacterial cellulose-hemicellulose composites.

    Science.gov (United States)

    Penttilä, Paavo A; Imai, Tomoya; Hemming, Jarl; Willför, Stefan; Sugiyama, Junji

    2018-06-15

    The production of biofuels and other chemicals from lignocellulosic biomass is limited by the inefficiency of enzymatic hydrolysis. Here a biomimetic composite material consisting of bacterial cellulose and wood-based hemicelluloses was used to study the effects of hemicelluloses on the enzymatic hydrolysis with a commercial cellulase mixture. Bacterial cellulose synthesized in the presence of hemicelluloses, especially xylan, was found to be more susceptible to enzymatic hydrolysis than hemicellulose-free bacterial cellulose. The reason for the easier hydrolysis could be related to the nanoscale structure of the substrate, particularly the packing of cellulose microfibrils into ribbons or bundles. In addition, small-angle X-ray scattering was used to show that the average nanoscale morphology of bacterial cellulose remained unchanged during the enzymatic hydrolysis. The reported easier enzymatic hydrolysis of bacterial cellulose produced in the presence of wood-based xylan offers new insights to overcome biomass recalcitrance through genetic engineering. Copyright © 2018 Elsevier Ltd. All rights reserved.

  17. Enzymatic production of biodiesel from microalgal oil using ethyl acetate as an acyl acceptor.

    Science.gov (United States)

    Alavijeh, Razieh Shafiee; Tabandeh, Fatemeh; Tavakoli, Omid; Karkhane, Aliasghar; Shariati, Parvin

    2015-01-01

    Microalgae have become an important source of biomass for biodiesel production. In enzymatic transesterification reaction, the enzyme activity is decreased in presence of alcohols. The use of different acyl acceptors such as methyl/ethyl acetate is suggested as an alternative and effective way to overcome this problem. In this study, ethyl acetate was used for the first time in the enzymatic production of biodiesel by using microalga, Chlorella vulgaris, as a triglyceride source. Enzymatic conversion of such fatty acids to biodiesel was catalyzed by Novozym 435 as an efficient immobilized lipase which is extensively used in biodiesel production. The best conversion yield of 66.71% was obtained at the ethyl acetate to oil molar ratio of 13:1 and Novozym 435 concentration of 40%, based on the amount of oil, and a time period of 72 h at 40℃. The results showed that ethyl acetate have no adverse effect on lipase activity and the biodiesel amount was not decreased even after seven transesterification cycles, so ethyl acetate has a great potential to be substituted for short-chain alcohols in transesterification reaction.

  18. Novel roles for well-known players: from tobacco mosaic virus pests to enzymatically active assemblies.

    Science.gov (United States)

    Koch, Claudia; Eber, Fabian J; Azucena, Carlos; Förste, Alexander; Walheim, Stefan; Schimmel, Thomas; Bittner, Alexander M; Jeske, Holger; Gliemann, Hartmut; Eiben, Sabine; Geiger, Fania C; Wege, Christina

    2016-01-01

    monitoring blood sugar concentrations, might profit particularly from the presence of TMV rods: Their surfaces were recently shown to stabilize enzymatic activities upon repeated consecutive uses and over several weeks. This review gives the reader a ride through strikingly diverse achievements obtained with TMV-based particles, compares them to the progress with related viruses, and focuses on latest results revealing special advantages for enzyme-based biosensing formats, which might be of high interest for diagnostics employing 'systems-on-a-chip'.

  19. Novel roles for well-known players: from tobacco mosaic virus pests to enzymatically active assemblies

    Directory of Open Access Journals (Sweden)

    Claudia Koch

    2016-04-01

    , e.g., for monitoring blood sugar concentrations, might profit particularly from the presence of TMV rods: Their surfaces were recently shown to stabilize enzymatic activities upon repeated consecutive uses and over several weeks. This review gives the reader a ride through strikingly diverse achievements obtained with TMV-based particles, compares them to the progress with related viruses, and focuses on latest results revealing special advantages for enzyme-based biosensing formats, which might be of high interest for diagnostics employing 'systems-on-a-chip'.

  20. Influence of enzymatic hydrolysis on the allergenic reactivity of processed cashew and pistachio.

    Science.gov (United States)

    Cuadrado, Carmen; Cheng, Hsiaopo; Sanchiz, Africa; Ballesteros, Isabel; Easson, Michael; Grimm, Casey C; Dieguez, M Carmen; Linacero, Rosario; Burbano, Carmen; Maleki, Soheila J

    2018-02-15

    Cashew and pistachio allergies are considered a serious health problem. Previous studies have shown that thermal processing, pressurization and enzymatic hydrolysis may reduce the allergenic properties of food by changing the protein structure. This study assesses the allergenic properties of cashew and pistachio after thermal treatment (boiling and autoclaving), with or without pressure (autoclaving), and multiple enzymatic treatments under sonication, by SDS-PAGE, western blot and ELISA, with serum IgE of allergic individuals, and mass spectroscopy. Autoclaving and enzymatic hydrolysis under sonication separately induced a measurable reduction in the IgE binding properties of pastes made from treated cashew and pistachio nuts. These treatments were more effective with pistachio allergens. However, heat combined with enzymatic digestion was necessary to markedly lower IgE binding to cashew allergens. The findings identify highly effective simultaneous processing conditions to reduce or even abolish the allergenic potency of cashew and pistachio. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Multiphoton manipulations of enzymatic photoactivity in aspartate aminotransferase.

    Science.gov (United States)

    Hill, Melissa P; Freer, Lucy H; Vang, Mai C; Carroll, Elizabeth C; Larsen, Delmar S

    2011-04-21

    The aspartate aminotransferase (AAT) enzyme utilizes the chromophoric pyridoxal 5'-phosphate (PLP) cofactor to facilitate the transamination of amino acids. Recently, we demonstrated that, upon exposure to blue light, PLP forms a reactive triplet state that rapidly (in microseconds) generates the high-energy quinonoid intermediate when bound to PLP-dependent enzymes [J. Am. Chem. Soc.2010, 132 (47), 16953-16961]. This increases the net catalytic activity (k(cat)) of AAT, since formation of the quinonoid is partially rate limiting via the thermally activated enzymatic pathway. The magnitude of observed photoenhancement initially scales linearly with pump fluence; however when a critical threshold is exceeded, the photoactivity saturates and is even suppressed at greater excitation fluences. The photodynamic mechanisms associated with this suppression behavior are characterized with the use of ultrafast multipulse pump-dump-probe and pump-repump-probe transient absorption techniques in combination with complementary two-color, steady-state excitation assays. Via multistate kinetic modeling of the transient ultrafast data and the steady-state assay data, the nonmonotonic incident power dependence of the photoactivty in AAT is decomposed into contributions from high-intensity dumping of the excited singlet state and repumping of the excited triplet state with induces the repopulation of the ground state via rapid intersystem crossing in the higher-lying triplet electronic manifold.

  2. Interaction with Single-stranded DNA-binding Protein Stimulates Escherichia coli Ribonuclease HI Enzymatic Activity

    Energy Technology Data Exchange (ETDEWEB)

    Petzold, Christine; Marceau, Aimee H.; Miller, Katherine H.; Marqusee, Susan; Keck, James L. (UW-MED); (UCB)

    2015-04-22

    Single-stranded (ss) DNA-binding proteins (SSBs) bind and protect ssDNA intermediates formed during replication, recombination, and repair reactions. SSBs also directly interact with many different genome maintenance proteins to stimulate their enzymatic activities and/or mediate their proper cellular localization. We have identified an interaction formed between Escherichia coli SSB and ribonuclease HI (RNase HI), an enzyme that hydrolyzes RNA in RNA/DNA hybrids. The RNase HI·SSB complex forms by RNase HI binding the intrinsically disordered C terminus of SSB (SSB-Ct), a mode of interaction that is shared among all SSB interaction partners examined to date. Residues that comprise the SSB-Ct binding site are conserved among bacterial RNase HI enzymes, suggesting that RNase HI·SSB complexes are present in many bacterial species and that retaining the interaction is important for its cellular function. A steady-state kinetic analysis shows that interaction with SSB stimulates RNase HI activity by lowering the reaction Km. SSB or RNase HI protein variants that disrupt complex formation nullify this effect. Collectively our findings identify a direct RNase HI/SSB interaction that could play a role in targeting RNase HI activity to RNA/DNA hybrid substrates within the genome.

  3. Feeding indices and enzymatic activities of carob moth Ectomyelois ceratoniae (Zeller (Lepidoptera: pyrallidae on two commercial pistachio cultivars and an artificial diet

    Directory of Open Access Journals (Sweden)

    Naeimeh Teimouri

    2015-01-01

    Full Text Available Feeding indices and enzymatic activities of Ectomyelois ceratoniae (Zeller were studied in a growth chamber under controlled conditions (29 ± 2 °C, relative humidity of 70 ± 5% and a photoperiod of 16:8 (L:D hours on two commercial Pistachio cultivars (Akbari and Kalequchi and an artificial diet. Feeding indices of E. ceratoniae larvae differed significantly on three hosts (P < 0.05. The relative consumption rate was calculated to be 5.36 ± 0.009, 11.10 ± 1.49 and 10.631 ± 0.599 (mg/mg/day on artificial diet, Akbari and Kalequchi cultivars, respectively. Carob moth larvae reared on Akbari cultivar showed the highest efficiency of conversion of digested food (ECD (5.64 ± 0.43. The highest amount of efficiency of conversion of ingested food (ECI was obtained on artificial diet but approximate digestibility (AD was the lowest on this diet. The highest enzymatic activities of alpha-amylase, general proteases and lipase were observed in the midgut of larvae reared on artificial diet. Total protein and lipid value were highest in larvae that were reared on artificial diet.

  4. Aqueous two-phase systems for extractive enzymatic hydrolysis of biomass

    DEFF Research Database (Denmark)

    Bussamra, Bianca Consorti; Azzoni, Sindelia Freitas; Mussatto, Solange I.

    and enzymes, phase diagrams and volumetric ratios. The results of this project will make possible to design a process that enables high sugar concentration during the hydrolysis reaction, overcoming one of the biggest drawbacks regarding the production of second-generation ethanol: the enzymatic inhibition...... optimal aqueous two-phase systems for the separation of sugars and enzymes, which allow the development of an improved second-generation ethanol process.......Sugars derived from lignocellulosic materials are the main carbon sources in bio-based processes aiming to produce renewable fuels and chemicals. One of the major drawbacks during enzymatic hydrolysis of lignocellulosic materials to obtainsugars is the inhibition of enzymes by reaction products...

  5. Production of a carob enzymatic extract: potential use as a biofertilizer.

    Science.gov (United States)

    Parrado, J; Bautista, J; Romero, E J; García-Martínez, A M; Friaza, V; Tejada, M

    2008-05-01

    In this paper, we describe a biological process that converts carob germ (CG), a proteinic vegetable by-product, into a water-soluble enzymatic hydrolyzate extract (CGHE). The chemical and physical properties are also described. The conversion is done using a proteolytic enzyme mixture. The main component of CGHE extracted by the enzymatic process is protein (68%), in the form of peptides and free amino acids, having a high content of glutamine and arginine, and a minor component of phytohormones, which are also extracted and solubilized from the CG. We have also compared its potential fertilizer/biostimulant capacity on growth, flowering, and fruiting of tomato plants (Licopericon pimpinellifolium cv. Momotaro) with that of an animal enzymatic protein hydrolyzate. CGHE had a significantly beneficial impact, most notably regarding the greater plant height, number of flowers per plant, and number of fruits per plant. This could be due primarily to its phytohormonal action.

  6. Operation variables in transesterification of vegetable oil: an enzymatic catalysis review

    Directory of Open Access Journals (Sweden)

    Andrés Felipe Rojas González

    2010-01-01

    Full Text Available This paper presents the results of a literature review regarding how operating conditions influence vegetable oil enzymatic transesterification yield. The following parameters were studied: temperature and time reaction, alcohol: oil molar ratio, alcohol type, biocatalyst type and concentration, solvent, mixed intensity, reagent purity and free fatty acid and moisture concentration. Yields greater than 90% can be achieved in the enzymatic catalyst of vegetable oil using 35-50°C temperatures, long time reactions (7- 90h and a 3:1alcohol: vegetable oil molar ratio; however, such values would intrinsically depend on the type of lipase and oil u- sed. It was also found that free fatty acid and moisture concentration were parameters which did not require rigorous control due to high enzyme specificity. Lipases immobilised from Pseudomona cepacia bacteria and Rhizopus orizae fungi were most used in vegetable oil enzymatic transesterification.

  7. Protein-Rich Fraction of Cnidoscolus urens (L. Arthur Leaves: Enzymatic Characterization and Procoagulant and Fibrinogenolytic Activities

    Directory of Open Access Journals (Sweden)

    Yamara A. S. de Menezes

    2014-03-01

    Full Text Available Proteolytic enzymes are important macromolecules in the regulation of biochemical processes in living organisms. Additionally, these versatile biomolecules have numerous applications in the industrial segment. In this study we have characterized a protein-rich fraction of Cnidoscolus urens (L. Arthur leaves, rich in proteolytic enzymes, and evaluated its effects on the coagulation cascade. Three protein-rich fractions were obtained from the crude extract of C. urens leaves by precipitation with acetone. Fraction F1.0 showed higher proteolytic activity upon azocasein, and thus, was chosen for subsequent tests. The proteolytic activity of F1.0 on fibrinogen was dose-dependent and time-dependent. The extract demonstrated procoagulant activity on citrated plasma and reduced the APTT, not exerting effects on PT. Despite the fibrin(ogenolytic activity, F1.0 showed no defibrinogenating activity in vivo. The fraction F1.0 did not express hemorrhagic nor hemolytic activities. The proteolytic activity was inhibited by E-64, EDTA and in the presence of metal ions, and increased when pretreated with reducing agents, suggesting that the observed activity was mostly due to cysteine proteases. Several bands with proteolytic activity were detected by zymography with gelatin, albumin and fibrinogen. The optimal enzymatic activity was observed in temperature of 60 °C and pH 5.0, demonstrating the presence of acidic proteases. In conclusion, these results could provide basis for the pharmacological application of C. urens proteases as a new source of bioactive molecules to treat bleeding and thrombotic disorders.

  8. DOTA-functionalized polylysine: a high number of DOTA chelates positively influences the biodistribution of enzymatic conjugated anti-tumor antibody chCE7agl.

    Directory of Open Access Journals (Sweden)

    Jürgen Grünberg

    Full Text Available Site-specific enzymatic reactions with microbial transglutaminase (mTGase lead to a homogenous species of immunoconjugates with a defined ligand/antibody ratio. In the present study, we have investigated the influence of different numbers of 1,4,7,10-tetraazacyclododecane-N-N'-N''-N'''-tetraacetic acid (DOTA chelats coupled to a decalysine backbone on the in vivo behavior of the chimeric monoclonal anti-L1CAM antibody chCE7agl. The enzymatic conjugation of (DOTA1-decalysine, (DOTA3-decalysine or (DOTA5-decalysine to the antibody heavy chain (via Gln295/297 gave rise to immunoconjugates containing two, six or ten DOTA moieties respectively. Radiolabeling of the immunoconjugates with (177Lu yielded specific activities of approximately 70 MBq/mg, 400 MBq/mg and 700 MBq/mg with increasing numbers of DOTA chelates. Biodistribution experiments in SKOV3ip human ovarian cancer cell xenografts demonstrated a high and specific accumulation of radioactivity at the tumor site for all antibody derivatives with a maximal tumor accumulation of 43.6±4.3% ID/g at 24 h for chCE7agl-[(DOTA-decalysine]2, 30.6±12.0% ID/g at 24 h for chCE7agl-[(DOTA3-decalysine]2 and 49.9±3.1% ID/g at 48 h for chCE7agl-[(DOTA5-decalysine]2. The rapid elimination from the blood of chCE7agl-[(DOTA-decalysine]2 (1.0±0.1% ID/g at 24 h is associated with a high liver accumulation (23.2±4.6% ID/g at 24 h. This behavior changed depending on the numbers of DOTA moieties coupled to the decalysine peptide with a slower blood clearance (5.1±1.0 (DOTA3 versus 11.7±1.4% ID/g (DOTA5, p<0.005 at 24 h and lower radioactivity levels in the liver (21.4±3.4 (DOTA3 versus 5.8±0.7 (DOTA5, p<0.005 at 24 h. We conclude that the site-specific and stoichiometric uniform conjugation of the highly DOTA-substituted decalysine ((DOTA5-decalysine to an anti-tumor antibody leads to the formation of immunoconjugates with high specific activity and excellent in vivo behavior and is a valuable option for

  9. Enzymatic network for production of ether amines from alcohols

    DEFF Research Database (Denmark)

    Palacio, Cyntia M.; Crismaru, Ciprian G.; Bartsch, Sebastian

    2016-01-01

    We constructed an enzymatic network composed of three different enzymes for the synthesis of valuable ether amines. The enzymatic reactions are interconnected to catalyze the oxidation and subsequent transamination of the substrate and to provide cofactor recycling. This allows production...... of the desired ether amines from the corresponding ether alcohols with inorganic ammonium as the only additional substrate. To examine conversion, individual and overall reaction equilibria were established. Using these data, it was found that the experimentally observed conversions of up to 60% observed...... for reactions containing 10mM alcohol and up to 280mM ammonia corresponded well to predicted conversions. The results indicate that efficient amination can be driven by high concentrations of ammonia and may require improving enzyme robustness for scale-up....

  10. Technical Aspects of Use of Ultrasound for Intensification of Enzymatic Bio-Processing: New Path to "Green Chemistry"

    Science.gov (United States)

    Use of enzymatic processing in the food, textile, and bio-fuel applications is becoming increasingly popular, primarily because of rapid introduction of a new variety of highly efficient enzymes. In general, an enzymatic bio-processing generates less toxic and readily biodegradable wastewater efflue...

  11. Bio-based alkyds by direct enzymatic bulk polymerization

    DEFF Research Database (Denmark)

    Nguyen, Hiep Dinh

    to a corresponding classical reference. In a further development of the system, it has been found possible to use the esters of pentaerythritol and stearic acid in combination with the penta-aze derivative for the preparation of pseudo alkyds containing only pentaerythritol as polyol with high degree of branching....... Bio-based alkyds prepared from a combination of glycerol, and tall oil fatty acids, and azelaic acid by enzymatic polymerization show improved hydrophobicity and lower glass transition temperatures compared to an alkyd prepared from the same raw materials by a classical boiling method. The enzymatic...... of pentaerythritol derivatized with azelaic acid (or penta-aze) was examined and tested for the production of more branched alkyd systems. A photostability test validated the concept, and the method also resulted in alkyds with improved hydrophobicity and lower glass transition temperatures compared...

  12. Process Evaluation Tools for Enzymatic Cascades Welcome Message

    DEFF Research Database (Denmark)

    Abu, Rohana

    improvement and implementation. Hence, the goal of this thesis is to evaluate the process concepts in enzymatic cascades in a systematic manner, using tools such as thermodynamic and kinetic analysis. Three relevant case studies have been used to exemplify the approach. In the first case study, thermodynamic......Biocatalysis is attracting significant attention from both academic and industrial scientists due to the excellent capability of enzyme to catalyse selective reactions. Recently, much interest has been shown in the application of enzymatic cascades as a useful tool in organic synthesis......, the kinetics can be controlled in a highly efficient way to achieve a sufficiently favourable conversion to a given target product. This is exemplified in the second case study, in the kinetic modelling of the formation of 2-ketoglutarate from glucoronate, the second case study. This cascade consists of 4...

  13. Enzymatic added extraction and clarification of fruit juices-A review.

    Science.gov (United States)

    Sharma, Harsh P; Patel, Hiral; Sugandha

    2017-04-13

    Enzymatic treatment for juice extraction is most commonly used now a days. The enzymatic process is claimed to offer a number of advantages over mechanical-thermal comminution of several fruit pulps. Enzymes are an integral component of modern fruit juice manufacturing and are highly suitable for optimizing processes. Their main purposes are: increase extraction of juice from raw material, increase processing efficiency (pressing, solid settling or removal), and generate a final product that is clear and visually attractive. Juice extraction can be done by using various mechanical processes, which may be achieved through diffusion extraction, decanter centrifuge, screw type juice extractor, fruit pulper and by different types of presses. Enzymatic treatment prior to mechanical extraction significantly improves juice recovery compared to any other extraction process. Enzymatic hydrolysis of the cell walls increases the extraction yield, reducing sugars, soluble dry matter content and galacturonic acid content and titrable acidity of the products. Enzymatic degradation of the biomaterial depends upon the type of enzyme, incubation time, incubation temperature, enzyme concentration, agitation, pH and use of different enzyme combinations. We can conclude from the technical literature that use of the enzymes i.e. cellulases, pectinases, amylases and combination of these enzymes can give better juice yield with superior quality of the fruit juice. Pectinase enzyme can give maximum juice yield i.e. 92.4% at 360 minutes incubation time, 37°C incubation temperature and 5 mg/100 g of enzyme concentration. Whereas the combination of two enzymes i.e. pectin methyl esterase (PME) and polygalacturonase (PG) at 120 minutes of incubation time, 50°C of incubation temperature and 0.05 mg/100 gm of enzymatic concentration can give the maximum yield of 96.8% for plum fruits. This paper discusses the use of enzymes in fruit juice production focusing on the juice recovery

  14. Oxymatrine attenuates hepatic steatosis in non-alcoholic fatty liver disease rats fed with high fructose diet through inhibition of sterol regulatory element binding transcription factor 1 (Srebf1) and activation of peroxisome proliferator activated receptor alpha (Pparα).

    Science.gov (United States)

    Shi, Li-juan; Shi, Lei; Song, Guang-yao; Zhang, He-fang; Hu, Zhi-juan; Wang, Chao; Zhang, Dong-hui

    2013-08-15

    The aim of this study was to examine the therapeutic effect of oxymatrine, a monomer isolated from the medicinal plant Sophora flavescens Ait, on the hepatic lipid metabolism in non-alcoholic fatty liver (NAFLD) rats and to explore the potential mechanism. Rats were fed with high fructose diet for 8 weeks to establish the NAFLD model, then were given oxymatrine treatment (40, 80, and 160 mg/kg, respectively) for another 8 weeks. Body weight gain, liver index, serum and liver lipids, and histopathological evaluation were measured. Enzymatic activity and gene expression of the key enzymes involved in the lipogenesis and fatty acid oxidation were assayed. The results showed that oxymatrine treatment reduced body weight gain, liver weight, liver index, dyslipidemia, and liver triglyceride level in a dose dependant manner. Importantly, the histopathological examination of liver confirmed that oxymatrine could decrease the liver lipid accumulation. The treatment also decreased the fatty acid synthase (FAS) enzymatic activity and increased the carnitine palmitoyltransferase 1A (CPT1A) enzymatic activity. Besides, oxymatrine treatment decreased the mRNA expression of sterol regulatory element binding transcription factor 1(Srebf1), fatty acid synthase (Fasn), and acetyl CoA carboxylase (Acc), and increased the mRNA expression of peroxisome proliferator activated receptor alpha (Pparα), carnitine palmitoyltransferase 1A (Cpt1a), and acyl CoA oxidase (Acox1) in high fructose diet induced NAFLD rats. These results suggested that the therapeutic effect of oxymatrine on the hepatic steatosis in high fructose diet induced fatty liver rats is partly due to down-regulating Srebf1 and up-regulating Pparα mediated metabolic pathways simultaneously. © 2013 Elsevier B.V. All rights reserved.

  15. Inhibition of tyrosinase-mediated enzymatic browning by sulfite and natural alternatives

    NARCIS (Netherlands)

    Kuijpers, T.F.M.; Vincken, J.P.

    2013-01-01

    Although sulfite is widely used to counteract enzymatic browning, its mechanism has remained largely unknown. We describe a double inhibitory mechanism of sulfite on enzymatic browning, affecting both the enzymatic oxidation of phenols into o‑quinones, as well as the non‑enzymatic

  16. Synthesis of highly dispersed Pt nanoclusters anchored graphene composites and their application for non-enzymatic glucose sensing

    International Nuclear Information System (INIS)

    Chang, Gang; Shu, Honghui; Huang, Qiwei; Oyama, Munetaka; Ji, Kai; Liu, Xiong; He, Yunbin

    2015-01-01

    Highlights: • PtNCs/graphene (PVP) composites were obtained by a clean and facile method. • The addition of graphene effectively promotes the catalytic performance of composites. • The highly dispersed PtNCs show superior electrocatalytic activity to glucose oxidation. • PtNCs/graphene (PVP) composites exhibit excellent stability and selectivity for nonenzymatic glucose detection. - Abstract: A facile and clean method by using ascorbic acid as mild reductant was developed to synthesize nanocomposites of graphene and platinum nanoclusters (PtNCs/graphene), in which Polyvinyl-Pyrrolidone (PVP) was added during the one-step reductive process so as to improve the dispersity of PtNCs on the graphene and decrease the size of PtNCs. By several characterization methods such as X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS), we demonstrated that Pt nanoclusters have successfully anchored on the surface of graphene sheets with average diameter of 22 nm. It was found that with the assistant of PVP, Pt nanoclusters appeared with smaller particle size and narrower particle size distribution. Cyclic voltammetry and amperometric methods were used to evaluate the electro-catalytic activity of the synthesized nanocomposites toward the oxidation of glucose in neutral media (0.1 M PBS, pH 7.4). The PtNCs/graphene exhibited a rapid response time (about 3 s), a broad linear range (1 mM to 25 mM), good stability, and sensitivity estimated to be 1.21 μA cm −2 mM −1 (R = 0.995, 71.9 μA cm −2 mM −1 vs. geometric area). Additionally, the impact from the oxidation of interferences can be effectively limited by choosing the appropriate detection potential. These results indicated a great potential of PtNCs/graphene in fabricating novel non-enzymatic glucose sensors with high performance

  17. Pretreatment by radiation and acids of chaff and its effect on enzymatic hydrolysis of cellulose

    International Nuclear Information System (INIS)

    Kumakura, M.; Kaetsu, I.

    1984-01-01

    The effect of pretreatment by radiation and acids—sulfuric, hydrochloric and acetic—on the enzymatic hydrolysis of chaff was studied. The combination of radiation and acids accelerates subsequent crushing and enzymatic hydrolysis. The percentage of fine powder below 115 mesh, after the crushing and the glucose yield on subsequent enzymatic hydrolysis, increased with increasing acid concentration, treatment time and irradiation dose. Radiation and hydrochloric acid pretreatment was the most effective in giving a high glucose conversion yield (about 90%). Irradiation dose, acid concentration, treatment temperature and treatment time were 20 Mrad, 0·5%, 70°C, and 5 h, respectively

  18. Production of Fish Hydrolysates Protein From Waste of Fish Carp (Cyprinus Carpio) by Enzymatic Hydrolysis

    OpenAIRE

    Saputra, Dede; Nurhayati, Tati

    2016-01-01

    Fish Protein Hydrolysates (FPH) is the mixed products of polypeptide, dipeptides, and amino acid. It can be produced from materials that contained of protein by acid reaction, base reaction or enzymatic hydrolysis. The objectives of this study were to study the production of FPH from fish carp meat at post rigor phase and viscera by enzymatic hydrolysis, to determine the specific activity of papain enzyme, and to determine the solubility of FPH. Capacity of fish hydrolyzing can be identified ...

  19. Physiological and enzymatic analyses of pineapple subjected to ionizing radiation

    International Nuclear Information System (INIS)

    Silva, Josenilda Maria da; Silva, Juliana Pizarro; Spoto, Marta Helena Fillet

    2007-01-01

    The physiological and enzymatic post-harvest characteristics of the pineapple cultivar Smooth Cayenne were evaluated after the fruits were gamma-irradiated with doses of 100 and 150 Gy and the fruits were stored for 10, 20 and 30 days at 12 deg C (±1) and relative humidity of 85% (±5). Physiological and enzymatic analyses were made for each storage period to evaluate the alterations resulting from the application of ionizing radiation. Control specimens showed higher values of soluble pectins, total pectins, reducing sugars, sucrose and total sugars and lower values of polyphenyloxidase and polygalacturonase enzyme activities. All the analyses indicated that storage time is a significantly influencing factor. The 100 Gy dosage and 20-day storage period presented the best results from the standpoint of maturation and conservation of the fruits quality. (author)

  20. Bioelectrocatalytic NAD+/NADH inter-conversion: transformation of an enzymatic fuel cell into an enzymatic redox flow battery.

    Science.gov (United States)

    Quah, Timothy; Milton, Ross D; Abdellaoui, Sofiene; Minteer, Shelley D

    2017-07-25

    Diaphorase and a benzylpropylviologen redox polymer were combined to create a bioelectrode that can both oxidize NADH and reduce NAD + . We demonstrate how bioelectrocatalytic NAD + /NADH inter-conversion can transform a glucose/O 2 enzymatic fuel cell (EFC) with an open circuit potential (OCP) of 1.1 V into an enzymatic redox flow battery (ERFB), which can be rapidly recharged by operation as an EFC.

  1. High-performance liquid chromatography analysis methods developed for quantifying enzymatic esterification of flavonoids in ionic liquids.

    Science.gov (United States)

    Lue, Bena-Marie; Guo, Zheng; Xu, Xuebing

    2008-07-11

    Methods using reversed-phase high-performance liquid chromatography (RP-HPLC) with ELSD were investigated to quantify enzymatic reactions of flavonoids with fatty acids in the presence of diverse room temperature ionic liquids (RTILs). A buffered salt (preferably triethylamine-acetate) was found essential for separation of flavonoids from strongly polar RTILs, whereby RTILs were generally visible as two major peaks identified based on an ion-pairing/exchanging hypothesis. C8 and C12 stationary phases were optimal while mobile phase pH (3-7) had only a minor influence on separation. The method developed was successfully applied for primary screening of RTILs (>20), with in depth evaluation of substrates in 10 RTILs, for their evaluation as reaction media.

  2. Functionalization of monolithic and porous three-dimensional graphene by one-step chitosan electrodeposition for enzymatic biosensor.

    Science.gov (United States)

    Liu, Jiyang; Wang, Xiaohui; Wang, Tianshu; Li, Dan; Xi, Fengna; Wang, Jin; Wang, Erkang

    2014-11-26

    Biological modification of monolithic and porous 3D graphene is of great significance for extending its application in fabricating highly sensitive biosensors. The present work reports on the first biofunctionalization of monolithic and freestanding 3D graphene foam for one-step preparation of reagentless enzymatic biosensors by controllable chitosan (CS) electrodeposition technology. Using a homogeneous three-component electrodeposition solution containing a ferrocene (Fc) grafted CS hybrid (Fc-CS), glucose oxidase (GOD), and single-walled carbon nanotubes (SWNTs), a homogeneous biocomposite film of Fc-CS/SWNTs/GOD was immobilized on the surface of 3D graphene foam by one-step electrodeposition. The Fc groups grafted on chitosan can be stably immobilized on the 3D graphene surface and keep their original electrochemical activity. The SWNTs doped into the Fc-CS matrix act as a nanowire to facilitate electron transfer and improve the conductivity of the biocomposite film. Combined with the extraordinary properties of 3D graphene foam including large active surface area, high conductivity, and fast mass transport dynamics, the 3D graphene based enzymatic biosensor achieved a large linear range (5.0 μM to 19.8 mM), a low detection limit (1.2 μM), and rapid response (reaching the 95% steady-state response within 8 s) for reagentless detection of glucose in the phosphate buffer solution.

  3. Haematology, genotoxicity, enzymatic activity and histopathology as biomarkers of metal pollution in the shrew Crocidura russula

    International Nuclear Information System (INIS)

    Sanchez-Chardi, A.; Marques, C.C.; Gabriel, S.I.; Capela-Silva, F.; Cabrita, A.S.; Lopez-Fuster, M.J.; Nadal, J.; Mathias, M.L.

    2008-01-01

    Haematological (WBC, RBC, Hgb and Hct) and genotoxicity (MNT) parameters, hepatic enzymatic activities (GST, GPx and GR), and a histopathological evaluation of liver, kidneys and gonads were assessed as general biomarkers of metal pollution in the shrew Crocidura russula inhabiting a pyrite mining area. Specimens exposed to metals presented a few significant alterations when compared with reference animals: GST activity decreased; micronuclei increased; and evident liver alterations related to metal exposure were observed. On the basis of all the parameters studied, age was an important factor that partly explained the observed variation, whereas sex was the least important factor. Significant correlations were also found between heavy metal concentrations and biomarkers evaluated, demonstrating the great influence of these metals in the metabolic alterations. To the best of our knowledge, these data constitute the first measurements of a battery of biomarkers in shrews from a mine site and are among the few available for insectivorous mammals. - Metals from an abandoned pyrite mine produce alterations in haematological parameters, GST, MNT, and histopathology in shrews

  4. Process development for gelatinisation and enzymatic hydrolysis of starch at high concentrations

    OpenAIRE

    Baks, T.

    2007-01-01

    cum laude graduation (with distinction) Enzymatic hydrolysis of starch is encountered in day-to-day life for instance in the dishwasher during removal of stains with detergents or in our mouth during chewing of starch-based foods in the presence of saliva. The reaction is also important for the (food) industry, for example for the production of beer or bio-ethanol. In industry, it is usually preceded by gelatinisation to make the starch molecules available for the enzymes. Both gelatinisation...

  5. Improved enzymatic production of phenolated glycerides through alkyl phenolate intermediate

    DEFF Research Database (Denmark)

    Yang, Zhiyong; Feddern, Vivian; Glasius, Marianne

    2011-01-01

    This work reported a novel approach for synthesis of dihydrocaffoylated glycerides, consisting of 2 steps: enzymatic synthesis of octyl dihydrocaffeate (as a synthetic intermediate) from octanol and dihydrocaffeic acid (DHCA), and enzymatic interesterification of triglycerides with octyl dihydroc......This work reported a novel approach for synthesis of dihydrocaffoylated glycerides, consisting of 2 steps: enzymatic synthesis of octyl dihydrocaffeate (as a synthetic intermediate) from octanol and dihydrocaffeic acid (DHCA), and enzymatic interesterification of triglycerides with octyl...

  6. Chemo‐enzymatic epoxidation–process options for improving biocatalytic productivity

    DEFF Research Database (Denmark)

    Hagström, Anna E. V.; Törnvall, Ulrika; Nordblad, Mathias

    2011-01-01

    The reactor choice is crucial when designing a process where inactivation of the biocatalyst is a problem. The main bottleneck for the chemo‐enzymatic epoxidation has been found to be enzyme inactivation by the hydrogen peroxide, H2O2, substrate. In the work reported here, the effect of reaction...... parameters on the reaction performance have been investigated and used to establish suitable operating strategies to minimize the inactivation of the enzyme, using rapeseed methyl ester (RME) as a substrate in a solvent‐free system. The use of a controlled fed‐batch reactor for maintaining H2O2 concentration...... at 1.5 M resulted in increased productivity, up to 76 grams of product per gram of biocatalyst with higher retention of enzyme activity. Further investigation included a multistage design that separated the enzymatic reaction and the saturation of the RME substrate with H2O2 into different vessels...

  7. Rational design of functional and tunable oscillating enzymatic networks

    Science.gov (United States)

    Semenov, Sergey N.; Wong, Albert S. Y.; van der Made, R. Martijn; Postma, Sjoerd G. J.; Groen, Joost; van Roekel, Hendrik W. H.; de Greef, Tom F. A.; Huck, Wilhelm T. S.

    2015-02-01

    Life is sustained by complex systems operating far from equilibrium and consisting of a multitude of enzymatic reaction networks. The operating principles of biology's regulatory networks are known, but the in vitro assembly of out-of-equilibrium enzymatic reaction networks has proved challenging, limiting the development of synthetic systems showing autonomous behaviour. Here, we present a strategy for the rational design of programmable functional reaction networks that exhibit dynamic behaviour. We demonstrate that a network built around autoactivation and delayed negative feedback of the enzyme trypsin is capable of producing sustained oscillating concentrations of active trypsin for over 65 h. Other functions, such as amplification, analog-to-digital conversion and periodic control over equilibrium systems, are obtained by linking multiple network modules in microfluidic flow reactors. The methodology developed here provides a general framework to construct dissipative, tunable and robust (bio)chemical reaction networks.

  8. Pretreatment of corn stover using wet oxidation to enhance enzymatic digestibility.

    Science.gov (United States)

    Varga, Eniko; Schmidt, Anette S; Réczey, Kati; Thomsen, Anne Belinda

    2003-01-01

    Corn stover is an abundant, promising raw material for fuel ethanol production. Although it has a high cellulose content, without pretreatment it resists enzymatic hydrolysis, like most lignocellulosic materials. Wet oxidation (water, oxygen, mild alkali or acid, elevated temperature and pressure) was investigated to enhance the enzymatic digestibility of corn stover. Six different combinations of reaction temperature, time, and pH were applied. The best conditions (60 g/L of corn stover, 195 degrees C, 15 min, 12 bar O2, 2 g/L of Na2CO3) increased the enzymatic conversion of corn stover four times, compared to untreated material. Under these conditions 60% of hemicellulose and 30% of lignin were solubilized, whereas 90% of cellulose remained in the solid fraction. After 24-h hydrolysis at 50 degrees C using 25 filter paper units (FPU)/g of drymatter (DM) biomass, the achieved conversion of cellulose to glucose was about 85%. Decreasing the hydrolysis temperature to 40 degrees C increased hydrolysis time from 24 to 72 h. Decreasing the enzyme loading to 5 FPU/g of DM biomass slightly decreased the enzymatic conversion from 83.4 to 71%. Thus, enzyme loading can be reduced without significantly affecting the efficiency of hydrolysis, an important economical aspect.

  9. Combined Enzymatic and Mechanical Cell Disruption and Lipid Extraction of Green Alga Neochloris oleoabundans

    Science.gov (United States)

    Wang, Dongqin; Li, Yanqun; Hu, Xueqiong; Su, Weimin; Zhong, Min

    2015-01-01

    Microalgal biodiesel is one of the most promising renewable fuels. The wet technique for lipids extraction has advantages over the dry method, such as energy-saving and shorter procedure. The cell disruption is a key factor in wet oil extraction to facilitate the intracellular oil release. Ultrasonication, high-pressure homogenization, enzymatic hydrolysis and the combination of enzymatic hydrolysis with high-pressure homogenization and ultrasonication were employed in this study to disrupt the cells of the microalga Neochloris oleoabundans. The cell disruption degree was investigated. The cell morphology before and after disruption was assessed with scanning and transmission electron microscopy. The energy requirements and the operation cost for wet cell disruption were also estimated. The highest disruption degree, up to 95.41%, assessed by accounting method was achieved by the combination of enzymatic hydrolysis and high-pressure homogenization. A lipid recovery of 92.6% was also obtained by the combined process. The combined process was found to be more efficient and economical compared with the individual process. PMID:25853267

  10. Combined Enzymatic and Mechanical Cell Disruption and Lipid Extraction of Green Alga Neochloris oleoabundans

    Directory of Open Access Journals (Sweden)

    Dongqin Wang

    2015-04-01

    Full Text Available Microalgal biodiesel is one of the most promising renewable fuels. The wet technique for lipids extraction has advantages over the dry method, such as energy-saving and shorter procedure. The cell disruption is a key factor in wet oil extraction to facilitate the intracellular oil release. Ultrasonication, high-pressure homogenization, enzymatic hydrolysis and the combination of enzymatic hydrolysis with high-pressure homogenization and ultrasonication were employed in this study to disrupt the cells of the microalga Neochloris oleoabundans. The cell disruption degree was investigated. The cell morphology before and after disruption was assessed with scanning and transmission electron microscopy. The energy requirements and the operation cost for wet cell disruption were also estimated. The highest disruption degree, up to 95.41%, assessed by accounting method was achieved by the combination of enzymatic hydrolysis and high-pressure homogenization. A lipid recovery of 92.6% was also obtained by the combined process. The combined process was found to be more efficient and economical compared with the individual process.

  11. Enzymatic properties and primary structures of hyaluronidases from two species of lionfish (Pterois antennata and Pterois volitans).

    Science.gov (United States)

    Kiriake, Aya; Madokoro, Mihoko; Shiomi, Kazuo

    2014-08-01

    Lionfish are representative venomous fish, having venomous glandular tissues in dorsal, pelvic and anal spines. Some properties and primary structures of proteinaceous toxins from the venoms of three species of lionfish, Pterois antennata, Pterois lunulata and Pterois volitans, have so far been clarified. Our recent survey established the presence of hyaluronidase, presumably a toxin-spreading factor, in the venoms of P. antennata and P. volitans. This prompted us to examine enzymatic properties and primary structures of lionfish hyaluronidases. The hyaluronidases of P. antennata and P. volitans were shown to be optimally active at pH 6.6, 37°C and 0.1 M NaCl and specifically active against hyaluronan. These enzymatic properties are almost the same as those of stonefish hyaluronidases. The primary structures (483 amino acid residues) of the lionfish hyaluronidases were elucidated by a cDNA cloning strategy using degenerate primers designed from the reported amino acid sequences of the stonefish hyaluronidases. Both lionfish hyaluronidases share as high as 99.6% of sequence identity with each other and also considerably high identities (72-77%) with the stonefish hyaluronidases but rather low identities (25-40%) with other hyaluronidases from mammals and venomous animals. In consistent with this, phylogenetic tree analysis revealed that the lionfish hyaluronidases, together with the stonefish hyaluronidases, form a cluster independently of other hyaluronidases. Nevertheless, the lionfish hyaluronidases as well as the stonefish hyaluronidases almost maintain structural features (active site, glyco_hydro_56 domain and cysteine location) observed in other hyaluronidases.

  12. ENCAPSULATION OF HORSERADISH PEROXIDASE-GLUCOSE OXIDASE (HRP-GOx IN SILICA AQUAGEL SYNTHESIZED FROM RICE HULL ASH FOR ENZYMATIC REACTION OF GLUCOSE

    Directory of Open Access Journals (Sweden)

    Nuryono Nuryono

    2010-06-01

    Full Text Available In recent years, the sol-gel technique has attracted increasing interest as a unique approach to immobilize biomolecules for bioanalytical applications as well as biochemical and biophysical studies. In this research, encapsulation of Horseradish peroxidase-Glucose oxidase (HRP-GOx enzymes in silica aquagel from rice hull ash by sol-gel process has been carried out. In addition, the effect of several parameters (weight ratio of HRP to GOx, pH, temperature, sodium ion concentration on enzyme activity was studied, as well. Rice hull ash, which was produced by ashing at 700 °C, was extracted it's silika by NaOH solution 1 M at 100 °C for two hours to produce sodium silikate (Na2SiO3 solution. The Na2SiO3 solution with pH of 13 was added with a strong cation exchanger resin, to produce sol solution with the pH of 4. Encapsulation was emphasized by mixing sol solution and phosphate buffer pH 7 containing HRP-GOx solution at volume ratio of buffer to sol solution 1:5. The mixture was transferred into 96-microwell plate and was aged for 24 hours. Enzymatic reaction was carried out by adding chromogenic solution of phenol and 4-aminoantipyrine (4-AAP and b-D-glucose solution (as substrate into the microwell. Enzymatic activity was examined by measuring absorbance of product solution at 490 nm with ELISA reader. Result of enzymatic activity for encapsulated enzymes (SGE was compared to that for free enzymes (EB. Results showed that at the investigated condition, HRP-GOx enzymes gave high activity at weight ratio of HRP to GOx 10:1 and pH 7 for both SGE and EB. Encapsulation caused the enzymes activity decrease to 53.0±0.2 %. However, SGE was observed to be more stable on pH and temperature changes than EB. Study on the effect of sodium concentration showed that the increase of sodium concentration from 0.10 to 0.37 M decreased the enzymatic activity to 56±0.2%. Reusability test showed that the synthesized SGE was reusable with activity decrease of 60

  13. Enzymatic desulfurization of coal

    Energy Technology Data Exchange (ETDEWEB)

    Boyer, Y.N.; Crooker, S.C.; Kitchell, J.P.; Nochur, S.V.

    1991-05-16

    The overall objective of this program was to investigate the feasibility of an enzymatic desulfurization process specifically intended for organic sulfur removal from coal. Toward that end, a series of specific objectives were defined: (1) establish the feasibility of (bio)oxidative pretreatment followed by biochemical sulfate cleavage for representative sulfur-containing model compounds and coals using commercially-available enzymes; (2) investigate the potential for the isolation and selective use of enzyme preparations from coal-utilizing microbial systems for desulfurization of sulfur-containing model compounds and coals; and (3) develop a conceptual design and economic analysis of a process for enzymatic removal of organic sulfur from coal. Within the scope of this program, it was proposed to carry out a portion of each of these efforts concurrently. (VC)

  14. Thermal-induced conformational changes in the product release area drive the enzymatic activity of xylanases 10B: Crystal structure, conformational stability and functional characterization of the xylanase 10B from Thermotoga petrophila RKU-1

    International Nuclear Information System (INIS)

    Santos, Camila Ramos; Meza, Andreia Navarro; Hoffmam, Zaira Bruna; Silva, Junio Cota; Alvarez, Thabata Maria; Ruller, Roberto; Giesel, Guilherme Menegon; Verli, Hugo; Squina, Fabio Marcio; Prade, Rolf Alexander; Murakami, Mario Tyago

    2010-01-01

    Research highlights: → The hyperthermostable xylanase 10B from Thermotoga petrophila RKU-1 produces exclusively xylobiose at the optimum temperature. → Circular dichroism spectroscopy suggests a coupling effect of temperature-induced structural changes with its enzymatic behavior. → Crystallographic and molecular dynamics studies indicate that conformational changes in the product release area modulate the enzyme action mode. -- Abstract: Endo-xylanases play a key role in the depolymerization of xylan and recently, they have attracted much attention owing to their potential applications on biofuels and paper industries. In this work, we have investigated the molecular basis for the action mode of xylanases 10B at high temperatures using biochemical, biophysical and crystallographic methods. The crystal structure of xylanase 10B from hyperthermophilic bacterium Thermotoga petrophila RKU-1 (TpXyl10B) has been solved in the native state and in complex with xylobiose. The complex crystal structure showed a classical binding mode shared among other xylanases, which encompasses the -1 and -2 subsites. Interestingly, TpXyl10B displayed a temperature-dependent action mode producing xylobiose and xylotriose at 20 o C, and exclusively xylobiose at 90 o C as assessed by capillary zone electrophoresis. Moreover, circular dichroism spectroscopy suggested a coupling effect of temperature-induced structural changes with this particular enzymatic behavior. Molecular dynamics simulations supported the CD analysis suggesting that an open conformational state adopted by the catalytic loop (Trp297-Lys326) provokes significant modifications in the product release area (+1,+2 and +3 subsites), which drives the enzymatic activity to the specific release of xylobiose at high temperatures.

  15. Thermal-induced conformational changes in the product release area drive the enzymatic activity of xylanases 10B: Crystal structure, conformational stability and functional characterization of the xylanase 10B from Thermotoga petrophila RKU-1

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Camila Ramos; Meza, Andreia Navarro [Laboratorio Nacional de Biociencias (LNBio), Centro Nacional de Pesquisa em Energia e Materiais, Campinas, SP (Brazil); Hoffmam, Zaira Bruna; Silva, Junio Cota; Alvarez, Thabata Maria; Ruller, Roberto [Laboratorio Nacional de Ciencia e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais, Campinas, SP (Brazil); Giesel, Guilherme Menegon; Verli, Hugo [Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS (Brazil); Squina, Fabio Marcio [Laboratorio Nacional de Ciencia e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais, Campinas, SP (Brazil); Prade, Rolf Alexander [Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK (United States); Murakami, Mario Tyago, E-mail: mario.murakami@lnbio.org.br [Laboratorio Nacional de Biociencias (LNBio), Centro Nacional de Pesquisa em Energia e Materiais, Campinas, SP (Brazil)

    2010-12-10

    Research highlights: {yields} The hyperthermostable xylanase 10B from Thermotoga petrophila RKU-1 produces exclusively xylobiose at the optimum temperature. {yields} Circular dichroism spectroscopy suggests a coupling effect of temperature-induced structural changes with its enzymatic behavior. {yields} Crystallographic and molecular dynamics studies indicate that conformational changes in the product release area modulate the enzyme action mode. -- Abstract: Endo-xylanases play a key role in the depolymerization of xylan and recently, they have attracted much attention owing to their potential applications on biofuels and paper industries. In this work, we have investigated the molecular basis for the action mode of xylanases 10B at high temperatures using biochemical, biophysical and crystallographic methods. The crystal structure of xylanase 10B from hyperthermophilic bacterium Thermotoga petrophila RKU-1 (TpXyl10B) has been solved in the native state and in complex with xylobiose. The complex crystal structure showed a classical binding mode shared among other xylanases, which encompasses the -1 and -2 subsites. Interestingly, TpXyl10B displayed a temperature-dependent action mode producing xylobiose and xylotriose at 20 {sup o}C, and exclusively xylobiose at 90 {sup o}C as assessed by capillary zone electrophoresis. Moreover, circular dichroism spectroscopy suggested a coupling effect of temperature-induced structural changes with this particular enzymatic behavior. Molecular dynamics simulations supported the CD analysis suggesting that an open conformational state adopted by the catalytic loop (Trp297-Lys326) provokes significant modifications in the product release area (+1,+2 and +3 subsites), which drives the enzymatic activity to the specific release of xylobiose at high temperatures.

  16. Graphene paper based bioelectrodes for enzymatic biofuel cells

    DEFF Research Database (Denmark)

    Werchmeister, Rebecka Maria Larsen; Shen, Fei; Zhang, Jingdong

    We aim at developing bioelectrodes for enzymatic biofuel cells, where sustainable and renewable enzymes are used for catalyzing the oxidation and reduction of fuel molecules. Here glucose is chosen as fuel molecule and glucose oxidase (GOx) is target enzyme which catalyzes the oxidation of glucose...... of glucose. This indicates that the enzyme has been successfully immobilized and is actively consuming glucose while transferring electrons to the graphene paper-GOx bioanode. Stability and efficiency of the bioelectrodes are under investigation....

  17. Changes in Enzymatic Activity of Fish and Slaughter Animals Meat after High Pressure Treatment at Subzero Temperatures

    Directory of Open Access Journals (Sweden)

    Malinowska-Pańczyk Edyta

    2018-06-01

    Full Text Available The aim of this study was to determine changes in the activity of proteolytic enzymes and transglutaminase of fish and mammal meat after pressurization at subzero temperatures. The activity was measured at the optimal pHs determined for enzymes from particular types of tested meat. It was found that increasing the pressure in the range of 60-193 MPa, did not change significantly the activity of acidic proteases of cod flesh, while the activity of neutral and alkaline proteases decreased drastically. Proteolytic enzymes from salmon flesh were more resistant than those from cod flesh. They maintained or increased (neutral protease activity after pressurization. The activity of the endogenous enzymes of bovine meat increased with pressure increase, except for acidic proteases, the activity of which was reduced after treatment at 193 MPa to the level similar to unpressurized meat. Endogenous proteases of porcine meat were activated by high-pressure treatment. It has been shown that activity of TGase in unpressurized flesh from cod was 5 times higher than that from unpressurized salmon. Depending on the type of meat, these enzymes were also significantly different in their sensitivity to pressure. The pressure of 60 and 193 MPa led to a complete inactivation of the TGase in cod flesh, while the activity of salmon flesh TGase was decreased only by 15 and 21%, respectively.

  18. Evaluation of Biological and Enzymatic Activity of Soil in a Tropical Dry Forest: Desierto de la Tatacoa (Colombia) with Potential in Mars Terraforming and Other Similar Planets

    Science.gov (United States)

    Moreno Moreno, A. N.

    2009-12-01

    Desierto de la Tatacoa has been determined to be a tropical dry forest bioma, which is located at 3° 13" N 75° 13" W. It has a hot thermal floor with 440 msnm of altitude; it has a daily average of 28° C, and a maximum of 40° C, Its annual rainfall total can be upwards of 1250 mm. Its solar sheen has a daily average of 5.8 hours and its relative humidity is between 60% and 65%. Therefore, the life forms presents are very scant, and in certain places, almost void. It was realized a completely random sampling of soil from its surface down to 6 inches deep, of zones without vegetation and with soils highly loaded by oxides of iron in order to determine the number of microorganisms per gram and its subsequent identification. It was measured the soil basal respiration. Besides, it was determined enzymatic activity (catalase, dehydrogenase, phosphatase and urease). Starting with the obtained results, it is developes an alternative towards the study of soil genesis in Mars in particular, and recommendations for same process in other planets. Although the information found in the experiments already realized in Martian soil they demonstrate that doesnt exist any enzymatic activity, the knowledge of the same topic in the soil is proposed as an alternative to problems like carbonic fixing of the dense Martian atmosphere of CO2, the degradation of inorganic compounds amongst other in order to prepare the substratum for later colonization by some life form.

  19. Enzymatic biodiesel production: Technical and economical considerations

    DEFF Research Database (Denmark)

    Munk Nielsen, Per; Brask, Jesper; Fjerbæk, Lene

    2008-01-01

    It is well documented in the literature that enzymatic processing of oils and fats for biodiesel is technically feasible. However, with very few exceptions, enzyme technology is not currently used in commercial-scale biodiesel production. This is mainly due to non-optimized process design...... and a lack of available costeffective enzymes. The technology to re-use enzymes has typically proven insufficient for the processes to be competitive. However, literature data documenting the productivity of enzymatic biodiesel together with the development of new immobilization technology indicates...... that enzyme catalysts can become cost effective compared to chemical processing. This work reviews the enzymatic processing of oils and fats into biodiesel with focus on process design and economy....

  20. Kinetic study of batch and fed-batch enzymatic saccharification of pretreated substrate and subsequent fermentation to ethanol

    Directory of Open Access Journals (Sweden)

    Gupta Rishi

    2012-03-01

    Full Text Available Abstract Background Enzymatic hydrolysis, the rate limiting step in the process development for biofuel, is always hampered by its low sugar concentration. High solid enzymatic saccharification could solve this problem but has several other drawbacks such as low rate of reaction. In the present study we have attempted to enhance the concentration of sugars in enzymatic hydrolysate of delignified Prosopis juliflora, using a fed-batch enzymatic hydrolysis approach. Results The enzymatic hydrolysis was carried out at elevated solid loading up to 20% (w/v and a comparison kinetics of batch and fed-batch enzymatic hydrolysis was carried out using kinetic regimes. Under batch mode, the actual sugar concentration values at 20% initial substrate consistency were found deviated from the predicted values and the maximum sugar concentration obtained was 80.78 g/L. Fed-batch strategy was implemented to enhance the final sugar concentration to 127 g/L. The batch and fed-batch enzymatic hydrolysates were fermented with Saccharomyces cerevisiae and ethanol production of 34.78 g/L and 52.83 g/L, respectively, were achieved. Furthermore, model simulations showed that higher insoluble solids in the feed resulted in both smaller reactor volume and shorter residence time. Conclusion Fed-batch enzymatic hydrolysis is an efficient procedure for enhancing the sugar concentration in the hydrolysate. Restricting the process to suitable kinetic regimes could result in higher conversion rates.

  1. Kinetic study of batch and fed-batch enzymatic saccharification of pretreated substrate and subsequent fermentation to ethanol

    Science.gov (United States)

    2012-01-01

    Background Enzymatic hydrolysis, the rate limiting step in the process development for biofuel, is always hampered by its low sugar concentration. High solid enzymatic saccharification could solve this problem but has several other drawbacks such as low rate of reaction. In the present study we have attempted to enhance the concentration of sugars in enzymatic hydrolysate of delignified Prosopis juliflora, using a fed-batch enzymatic hydrolysis approach. Results The enzymatic hydrolysis was carried out at elevated solid loading up to 20% (w/v) and a comparison kinetics of batch and fed-batch enzymatic hydrolysis was carried out using kinetic regimes. Under batch mode, the actual sugar concentration values at 20% initial substrate consistency were found deviated from the predicted values and the maximum sugar concentration obtained was 80.78 g/L. Fed-batch strategy was implemented to enhance the final sugar concentration to 127 g/L. The batch and fed-batch enzymatic hydrolysates were fermented with Saccharomyces cerevisiae and ethanol production of 34.78 g/L and 52.83 g/L, respectively, were achieved. Furthermore, model simulations showed that higher insoluble solids in the feed resulted in both smaller reactor volume and shorter residence time. Conclusion Fed-batch enzymatic hydrolysis is an efficient procedure for enhancing the sugar concentration in the hydrolysate. Restricting the process to suitable kinetic regimes could result in higher conversion rates. PMID:22433563

  2. Green enzymatic production of glyceryl monoundecylenate using immobilized Candida antarctica lipase B.

    Science.gov (United States)

    Yadav, Manish G; Kavadia, Monali R; Vadgama, Rajeshkumar N; Odaneth, Annamma A; Lali, Arvind M

    2017-11-26

    Enzymatic synthesis of glyceryl monoundecylenate (GMU) was performed using indigenously immobilized Candida anatarctica lipase B preparation (named as PyCal) using glycerol and undecylenic acid as substrates. The effect of molar ratio, enzyme load, reaction time, and organic solvent on the reaction conversion was determined. Both batch and continuous processes for GMU synthesis with shortened reaction time were developed. Under optimized batch reaction conditions such as 1:5 molar ratio of undecylenic acid and glycerol, 2 h of reaction time at 30% substrate concentration in tert-butyl alcohol, conversion of 82% in the absence of molecular sieve, and conversion of 93% in the presence of molecular sieve were achieved. Packed bed reactor studies resulted in high conversion of 86% in 10-min residence time. Characterization of formed GMU was performed by FTIR, MS/MS. Enzymatic process resulted in GMU as a predominant product in high yield and shorter reaction time periods with GMU content of 92% and DAG content of 8%. Optimized GMU synthesis in the present study can be used as a useful reference for industrial synthesis of fatty acid esters of glycerol by the enzymatic route.

  3. Enzymatic biodiesel synthesis. Key factors affecting efficiency of the process

    Energy Technology Data Exchange (ETDEWEB)

    Szczesna Antczak, Miroslawa; Kubiak, Aneta; Antczak, Tadeusz; Bielecki, Stanislaw [Institute of Technical Biochemistry, Faculty of Biotechnology and Food Sciences, Technical University of Lodz, Stefanowskiego 4/10, 90-924 Lodz (Poland)

    2009-05-15

    Chemical processes of biodiesel production are energy-consuming and generate undesirable by-products such as soaps and polymeric pigments that retard separation of pure methyl or ethyl esters of fatty acids from glycerol and di- and monoacylglycerols. Enzymatic, lipase-catalyzed biodiesel synthesis has no such drawbacks. Comprehension of the latter process and an appreciable progress in production of robust preparations of lipases may soon result in the replacement of chemical catalysts with enzymes in biodiesel synthesis. Engineering of enzymatic biodiesel synthesis processes requires optimization of such factors as: molar ratio of substrates (triacylglycerols: alcohol), temperature, type of organic solvent (if any) and water activity. All of them are correlated with properties of lipase preparation. This paper reports on the interplay between the crucial parameters of the lipase-catalyzed reactions carried out in non-aqueous systems and the yield of biodiesel synthesis. (author)

  4. Evaluation of peroxidases from roots of Cyperus hermaphroditus as enzymatic mechanisms in phenanthrene oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Guerrero Zuniga, A. [Inst. Mexicano del Petroleo, Mexico City (Mexico). Environmental Protection Management Office; Rodriguez Dorantes, A.M. [Lab. Fisiologia Vegetal, Escuela Nacional de Ciencias Biologicas, Mexico City (Mexico). Depto Botanica

    2006-07-01

    Although phenanthrene is not mutagenic or carcinogenic, it has been shown to be toxic to aquatic organisms. This study evaluated in-vitro phenanthrene oxidation by peroxidases from radical extracts of Cyperus hermaphroditus plants. The characterization of oxidation products of phenanthrene related to the induction of root peroxidases was also examined. Concentrated ethanol stock of phenanthrene solution was added to the mineral solution of each plant container. The total radical biomass was placed in 4.5 ml of an ionic solution to analyze the enzymatic activity of the extracellular peroxidases. The total protein for each experiment was quantified by the Bradford method. Extracellular peroxidases activity was measured using the spectrophotometric method. The amount of radical biomass was quantified as high in the 80 and 120 ppm phenanthrene treatments relative to the control plants. It was suggested that the nature of the Cyperaceae roots combined with the high-octanol water coefficient and a low water solubility for phenanthrene may have facilitated the stabilization of the contaminant towards the roots. The ability of Cyperus hermaphroditus to immobilize phenanthrene through its adhesion was encouraged by the conditions of the hydroponic culture system. The adsorption of phenanthrene was increased with the time of exposure to the contaminant due to the greater total root mass. The study also showed the transformation of phenanthrene by radical extracts of Cyperus hermaphroditus containing guaiacol peroxidases with 12 per cent residual phenanthrene in the in vitro assays. The spectrophotometric analysis confirmed that the enzymatic systems are responsible for the phytotransformation of the pollutant. 9 refs., 2 tabs., 5 figs.

  5. Comparison of enzymatic activities in different Candida species isolated from women with vulvovaginitis.

    Science.gov (United States)

    Fatahinia, M; Halvaeezadeh, M; Rezaei-Matehkolaei, A

    2017-06-01

    Comparing the activities of secreted enzymes in different fungal species can improve our understanding of their pathogenic role. Secretion of various enzymes by Candida species has been considered for determination of their virulence in different Candida infections including vulvovaginitis. The aim of this study was to determine and compare the activity of secreted enzymes in Candidia strains isolated from women suspected to vulvovaginal candidiasis (VVC) and referred to some health centers in Khuzestan, Southwestern Iran. The vaginal secretion samples were taken by swap from 250 suspected women with symptoms of vulvovaginal candidiasis and cultured on CHROMagar Candida medium. Identification of the isolated Candida from culture positive samples performed by the color of colonies and some standard mycological procedures. Activities of phospholipase, hemolysin-α, hemolysin-β, esterase and proteinase were measured in vitro by standard laboratory protocols. The enzymatic activity index (EAI) was calculated for each enzyme in accordance to relevant protocols. Totally in eighty cases (32%), a Candida strain was isolated which found to be as 52 (65%) Candida albicans; 12 (15%) C. glabrata; 10 (12.5%) C. dubliniensis; 4 (5%) C. krusei, C. tropicalis and C. parapsilosis species (each=1; 1.3%). Among C. albicans strains, 89.1% produced all studied enzymes, while 86% of C. glabrata strains failed to produce proteinase and phospholipase. The EAIs in decreasing order were as hemolysin-β=0.2895, hemolysin-α=0.5420, esterase=0.5753, proteinase=0.7413, and phospholipase=0.7446, respectively. Activity of phospholipase, esterase and proteinase secreted by C. albicans and C. dubliniensis were significantly more than those released by C. glabrata and C. krusei, while 86% of C. glabrata strains did not show esterase activity. On the other hand, the activity rates of hemolysin α and β among all studied isolates were almost similar. In the present study, the prevalence

  6. Enzymatic modification of egg lecithin to improve properties.

    Science.gov (United States)

    Asomaning, Justice; Curtis, Jonathan M

    2017-04-01

    This research studied the enzymatic modification of egg yolk phospholipids and its effect on physicochemical properties. Egg yolk lipids were extracted with food grade ethanol and egg phospholipids (ePL) produced by deoiling with acetone. Vegetable oils were used to interesterify ePL utilizing Lipozyme®: sn-1,3 specific lipase. The enzymatic interesterification resulted in a single phase liquid product, whereas simple blending of the ePL and vegetable oil resulted in a product with two phases. In addition solid fat content decreased by 50% at -10°C and 94% at 35°C when compared with egg yolk lipids extract. A decrease in melting temperature resulted from the interesterification process. Interesterification improved emulsion stability index when used as an emulsifier in oil-in-water emulsion and compared to the native and soy lecithin. Enzyme reusability test showed retention of 63% activity after 10 cycles. Overall, the properties of native egg phospholipids were significantly enhanced in a potentially useful manner through interesterification. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. SACCHARIFICATION OF NATIVE CASSAVA STARCH AT HIGH DRY SOLIDS IN AN ENZYMATIC MEMBRANE REACTOR

    Directory of Open Access Journals (Sweden)

    I Nyoman Widiasa

    2012-02-01

    Full Text Available This study is aimed to develop a novel process scheme for hydrolysis of native cassava starch at high dry solids using an enzymatic membrane reactor (EMR. Firstly, liquefied cassava starch having solids content up to 50% by weight was prepared by three stage liquefactions in a conventional equipment using a commercially available heat stable a-amylase (Termamyl 120L. The liquefied cassava starch was further saccharified in an EMR using glucoamylase (AMG E. By using the developed process scheme, a highly clear hydrolysate with dextrose equivalent (DE approximately 97 could be produced, provided the increase of solution viscosity during the liquefaction was precisely controlled. The excessive space time could result in reduction in conversion degree of starch. Moreover, a residence time distribution study confirmed that the EMR could be modelled as a simple continuous stirred tank reactor (CSTR. Using Lineweaver-Burk analysis, the apparent Michaelis-Menten constant (Km and glucose production rate constant (k2 were 552 (g/l and 4.04 (min-1, respectively. Application of simple CSTR model with those kinetic parameters was quietly appropriate to predict the reactor’s performance at low space time.

  8. Analysis, pretreatment and enzymatic saccharification of different fractions of Scots pine

    Science.gov (United States)

    2014-01-01

    Background Forestry residues consisting of softwood are a major lignocellulosic resource for production of liquid biofuels. Scots pine, a commercially important forest tree, was fractionated into seven fractions of chips: juvenile heartwood, mature heartwood, juvenile sapwood, mature sapwood, bark, top parts, and knotwood. The different fractions were characterized analytically with regard to chemical composition and susceptibility to dilute-acid pretreatment and enzymatic saccharification. Results All fractions were characterized by a high glucan content (38-43%) and a high content of other carbohydrates (11-14% mannan, 2-4% galactan) that generate easily convertible hexose sugars, and by a low content of inorganic material (0.2-0.9% ash). The lignin content was relatively uniform (27-32%) and the syringyl-guaiacyl ratio of the different fractions were within the range 0.021-0.025. The knotwood had a high content of extractives (9%) compared to the other fractions. The effects of pretreatment and enzymatic saccharification were relatively similar, but without pretreatment the bark fraction was considerably more susceptible to enzymatic saccharification. Conclusions Since sawn timber is a main product from softwood species such as Scots pine, it is an important issue whether different parts of the tree are equally suitable for bioconversion processes. The investigation shows that bioconversion of Scots pine is facilitated by that most of the different fractions exhibit relatively similar properties with regard to chemical composition and susceptibility to techniques used for bioconversion of woody biomass. PMID:24641769

  9. Enzymatic hydrolysis of lactose of whey permeate

    Directory of Open Access Journals (Sweden)

    Karina Nascimento de Almeida

    2015-09-01

    Full Text Available The whey permeate is the residual of the concentration process of the whey proteins by ultrafiltration method. It contains important nutrients such as lactose, minerals and some proteins and lipids. It is without an ending industrial waste that causes serious damage to the environment. For its full use the lactose must be hydrolyzed to enable its consumption by intolerant people. The enzymatic hydrolysis by lactase (β-galactosidase of Kluyveromyces lactis yeast is a safe method that does not compromise the integrity of other nutrients, enabling further use of the permeate as a raw material. This study aimed to perform tests of enzymatic hydrolysis of lactose in whey permeate formulations in a concentration of 0.2%, 0.7% and 1% at 30, 60 and 90 minutes with pH 6.3 medium and 37 °C. The reactions were monitored by high performance liquid chromatography which showed that the enzyme concentration of 0.7% at time 30 minutes formulations became safe for consumption by lactose intolerant people, according to minimum levels established by law.

  10. Enzymatic hydrolysis of pretreated barley and wheat straw

    DEFF Research Database (Denmark)

    Rosgaard, Lisa

    2007-01-01

    . The work involved evaluation of 1) possible ways to increase the glucose release from the commercial cellulase product Celluclast by boosting with other enzyme activities to increase the enzymatic hydrolysis, 2) comparing differently pretreated feedstock substrates and 3) evaluating a fed-batch substrate...... mixture resulted in a glucose release corresponding to ~84 % of the glucose release from Celluclast. It was therefore suggested that other enzyme activities than the 4 four main cellulase activities in Celluclast are necessary for optimal hydrolysis of lignocellulose. Even though Celluclast...... is a multicomponent cellulase mixture, there are still possibilities for further improvement in terms of providing the most efficient cellulase mixture for lignocellulose hydrolysis. It was shown that substrates evaluated all had some residual hemicellulose in the solid cellulose fraction after pretreatment...

  11. Susceptibility to antifungal agents and enzymatic activity of Candida haemulonii and Cutaneotrichosporon dermatis isolated from soft corals on the Brazilian reefs.

    Science.gov (United States)

    Pagani, Danielle M; Heidrich, Daiane; Paulino, Gustavo V B; de Oliveira Alves, Karine; Dalbem, Paula T; de Oliveira, Caroline F; Andrade, Zélia M M; Silva, Carolini; Correia, Monica D; Scroferneker, Maria Lúcia; Valente, Patricia; Landell, Melissa Fontes

    2016-12-01

    Candida is a common fungus with the capacity to cause infections in humans. However, most studies have concentrated on clinical isolates and little is known about the identity, ecology and drug resistance of free living species/strains. Here, we isolate eight strains of Candida haemulonii and four strains of Cutaneotrichosporon dermatis from three marine cnidarian zoanthids species (Palythoa caribaeorum, Palythoa variabilis and Zoanthus sociatus) collected from Brazilian coral reefs. Strains were identified by sequencing of the D1/D2 domain LSU rDNA and ITS region. We tested these environmental isolates for their capacity to grow in media with increasing concentration of NaCl, capacity to grow in different temperatures, enzymatic activity and antifungal susceptibility. For C. haemulonii, all strains strongly produced gelatinase, esterase and albuminase and were either able to express lipase, phospholipase and keratinase, but not express urease and DNase. The strains were able to grow at 37 °C, but not at 39 °C, and except for LMS 40, all of them could grow in a 10 % NaCl medium. All isolates were resistant to all antifungals tested, with exception for ketoconazole and tioconazole (MIC = 2 µg/mL). For C. dermatis, all strains could grow at 39 °C and could not express phospholipase, keratinase or gelatinase. However, all were capable of expressing urease, lipase and esterase. Three out of four strains could grow in a 10 % NaCl medium, but none grew in a 30 % NaCl medium. The strains showed high values of minimal inhibitory concentration. LMPV 90 was resistant to tioconazole, terbinafine, fluconazole and posaconazole, and LMS 38 was resistant to all antifungal agents tested. We discuss the characterization of C. haemulonii and C. dermatis as a possible emerging pathogen due to its animal-related enzymatic arsenal and antifungal resistance.

  12. Effect of alkali lignins with different molecular weights from alkali pretreated rice straw hydrolyzate on enzymatic hydrolysis.

    Science.gov (United States)

    Li, Yun; Qi, Benkun; Luo, Jianquan; Wan, Yinhua

    2016-01-01

    This study investigated the effect of alkali lignins with different molecular weights on enzymatic hydrolysis of lignocellulose. Different alkali lignins fractions, which were obtained from cascade ultrafiltration, were added into the dilute acid pretreated (DAP) and alkali pretreated (AP) rice straws respectively during enzymatic hydrolysis. The results showed that the addition of alkali lignins enhanced the hydrolysis and the enhancement for hydrolysis increased with increasing molecular weights of alkali lignins, with maximum enhancement being 28.69% for DAP and 20.05% for AP, respectively. The enhancement was partly attributed to the improved cellulase activity, and filter paper activity increased by 18.03% when adding lignin with highest molecular weight. It was found that the enhancement of enzymatic hydrolysis was correlated with the adsorption affinity of cellulase on alkali lignins, and the difference in surface charge and hydrophobicity of alkali lignins were responsible for the difference in affinity between cellulase and lignins. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Scale-up and integration of alkaline hydrogen peroxide pretreatment, enzymatic hydrolysis, and ethanolic fermentation.

    Science.gov (United States)

    Banerjee, Goutami; Car, Suzana; Liu, Tongjun; Williams, Daniel L; Meza, Sarynna López; Walton, Jonathan D; Hodge, David B

    2012-04-01

    Alkaline hydrogen peroxide (AHP) has several attractive features as a pretreatment in the lignocellulosic biomass-to-ethanol pipeline. Here, the feasibility of scaling-up the AHP process and integrating it with enzymatic hydrolysis and fermentation was studied. Corn stover (1 kg) was subjected to AHP pretreatment, hydrolyzed enzymatically, and the resulting sugars fermented to ethanol. The AHP pretreatment was performed at 0.125 g H(2) O(2) /g biomass, 22°C, and atmospheric pressure for 48 h with periodic pH readjustment. The enzymatic hydrolysis was performed in the same reactor following pH neutralization of the biomass slurry and without washing. After 48 h, glucose and xylose yields were 75% and 71% of the theoretical maximum. Sterility was maintained during pretreatment and enzymatic hydrolysis without the use of antibiotics. During fermentation using a glucose- and xylose-utilizing strain of Saccharomyces cerevisiae, all of the Glc and 67% of the Xyl were consumed in 120 h. The final ethanol titer was 13.7 g/L. Treatment of the enzymatic hydrolysate with activated carbon prior to fermentation had little effect on Glc fermentation but markedly improved utilization of Xyl, presumably due to the removal of soluble aromatic inhibitors. The results indicate that AHP is readily scalable and can be integrated with enzyme hydrolysis and fermentation. Compared to other leading pretreatments for lignocellulosic biomass, AHP has potential advantages with regard to capital costs, process simplicity, feedstock handling, and compatibility with enzymatic deconstruction and fermentation. Biotechnol. Bioeng. 2012; 109:922-931. © 2011 Wiley Periodicals, Inc. Copyright © 2011 Wiley Periodicals, Inc.

  14. Enzymatic Inverse Opal Hydrogel Particles for Biocatalyst.

    Science.gov (United States)

    Wang, Huan; Gu, Hongcheng; Chen, Zhuoyue; Shang, Luoran; Zhao, Ze; Gu, Zhongze; Zhao, Yuanjin

    2017-04-19

    Enzymatic carriers have a demonstrated value for chemical reactions and industrial applications. Here, we present a novel kind of inverse opal hydrogel particles as the enzymatic carriers. The particles were negatively replicated from spherical colloidal crystal templates by using magnetic nanoparticles tagged acrylamide hydrogel. Thus, they were endowed with the features of monodispersity, small volume, complete penetrating structure, and controllable motion, which are all beneficial for improving the efficiency of biocatalysis. In addition, due to the ordered porous nanostructure, the inverse opal hydrogel particles were imparted with unique photonic band gaps (PBGs) and vivid structural colors for encoding varieties of immobilized enzymes and for constructing a multienzymes biocatalysis system. These features of the inverse opal hydrogel particles indicate that they are ideal enzymatic carriers for biocatalysis.

  15. Dual functional rhodium oxide nanocorals enabled sensor for both non-enzymatic glucose and solid-state pH sensing.

    Science.gov (United States)

    Dong, Qiuchen; Huang, Yikun; Song, Donghui; Wu, Huixiang; Cao, Fei; Lei, Yu

    2018-07-30

    Both pH-sensitive and glucose-responsive rhodium oxide nanocorals (Rh 2 O 3 NCs) were synthesized through electrospinning followed by high-temperature calcination. The as-prepared Rh 2 O 3 NCs were systematically characterized using various advanced techniques including scanning electron microscopy, X-ray powder diffraction and Raman spectroscopy, and then employed as a dual functional nanomaterial to fabricate a dual sensor for both non-enzymatic glucose sensing and solid-state pH monitoring. The sensing performance of the Rh 2 O 3 NCs based dual sensor toward pH and glucose was evaluated using open circuit potential, cyclic voltammetry and amperometric techniques, respectively. The results show that the as-prepared Rh 2 O 3 NCs not only maintain accurate and reversible pH sensitivity of Rh 2 O 3 , but also demonstrate a good electrocatalytic activity toward glucose oxidation in alkaline medium with a sensitivity of 11.46 μA mM -1 cm -2 , a limit of detection of 3.1 μM (S/N = 3), and a reasonable selectivity against various interferents in non-enzymatic glucose detection. Its accuracy in determining glucose in human serum samples was further demonstrated. These features indicate that the as-prepared Rh 2 O 3 NCs hold great promise as a dual-functional sensing material in the development of a high-performance sensor forManjakkal both solid-state pH and non-enzymatic glucose sensing. Copyright © 2018 Elsevier B.V. All rights reserved.

  16. A novel In-situ Enzymatic Cleaning Method for Reducing Membrane Fouling in Membrane Bioreactors (MBRs

    Directory of Open Access Journals (Sweden)

    M. R. Bilad

    2016-05-01

    Full Text Available A novel in-situ enzymatic cleaning method was developed for fouling control in membrane bioreactors (MBRs. It is achieved by bringing the required enzymes near the membrane surface by pulling the enzymes to a magnetic membrane (MM surface by means of magnetic forces, exactly where the cleaning is required. To achieve this, the enzyme was coupled to a magnetic nanoparticle (MNP and the membrane it self was loaded with MNP. The magnetic activity was turned by means of an external permanent magnet. The effectiveness of concept was tested in a submerged membrane filtration using the model enzyme-substrate of Bacillus subitilis xylanase-arabinoxylan. The MM had almost similar properties compared to the unloaded ones, except for its well distributed MNPs. The enzyme was stable during coupling conditions and the presence of coupling could be detected using a high-performance anion-exchange chromatography (HPAEC analysis and Fourier transform infrared spectroscopy (FTIR. The system facilitated an in-situ enzymatic cleaning and could be effectively applied for control fouling in membrane bioreactors (MBRs.

  17. Anticancer system created by acrolein and hydroxyl radical generated in enzymatic oxidation of spermine and other biochemical reactions.

    Science.gov (United States)

    Alarcon, R A

    2012-10-01

    A hypothesis suggesting the existence of a ubiquitous physiological anticancer system created by two highly reactive oxidative stress inducers with anticancer properties, acrolein and hydroxyl radical, is reported in this communication. Both components can originate separately or together in several biochemical interactions, among them, the enzymatic oxidation of the polyamine spermine, which appear to be their main source. The foundations of this hypothesis encompass our initial search for growth-inhibitors or anticancer compounds in biological material leading to the isolation of spermine, a polyamine that became highly cytotoxic through the generation of acrolein, when enzymatically oxidized. Findings complemented with pertinent literature data by other workers and observed anticancer activities by sources capable of producing acrolein and hydroxyl radical. This hypothesis obvious implication: spermine enzymatic oxidations or other biochemical interactions that would co-generate acrolein and hydroxyl radical, the anticancer system components, should be tried as treatments for any given cancer. The biochemical generation of acrolein observed was totally unexpected, since this aldehyde was known; as a very toxic and highly reactive xenobiotic chemical produced in the pyrolysis of fats and other organic material, found as an atmospheric pollutant, in tobacco smoke and car emissions, and mainly used as a pesticide or aquatic herbicide. Numerous studies on acrolein, considered after our work a biological product, as well, followed. In them, acrolein widespread presence, its effects on diverse cellular proteins, such as, growth factors, and its anticancer activities, were additionally reported. Regarding hydroxyl radical, the second component of the proposed anticancer system, and another cytotoxic product in normal cell metabolism, it co-generates with acrolein in several biochemical interactions, occurrences suggesting that these products might jointly fulfill some

  18. Imbalanced nutrient recycling in a warmer ocean driven by differential response of extracellular enzymatic activities

    KAUST Repository

    Ayo, Begoñ a; Abad, Naiara; Artolozaga, Itxaso; Azua, Iñ igo; Bañ a, Zuriñ e; Unanue, Marian; Gasol, Josep M.; Duarte, Carlos M.; Iriberri, Juan

    2017-01-01

    Ocean oligotrophication concurrent with warming weakens the capacity of marine primary producers to support marine food webs and act as a CO2 sink, and is believed to result from reduced nutrient inputs associated to the stabilization of the thermocline. However, nutrient supply in the oligotrophic ocean is largely dependent on the recycling of organic matter. This involves hydrolytic processes catalyzed by extracellular enzymes released by bacteria, which temperature-dependence has not yet been evaluated. Here we report a global assessment of the temperature-sensitivity, as represented by the activation energies (Ea ), of extracellular β-glucosidase (βG), leucine aminopeptidase (LAP) and alkaline phosphatase (AP) enzymatic activities, which enable the uptake by bacteria of substrates rich in carbon, nitrogen and phosphorus, respectively. These Ea were calculated from two different approaches, temperature experimental manipulations and a space-for-time substitution approach, which generated congruent results. The three activities showed contrasting Ea in the subtropical and tropical ocean, with βG increasing the fastest with warming, followed by LAP, while AP showed the smallest increase. The estimated activation energies predict that the hydrolysis products under projected warming scenarios will have higher C:N, C:P and N:P molar ratios than those currently generated, and suggest that the warming of oceanic surface waters leads to a decline in the nutrient supply to the microbial heterotrophic community relative to that of carbon, particularly so for phosphorus, slowing down nutrient recycling and contributing to further ocean oligotrophication. This article is protected by copyright. All rights reserved.

  19. Imbalanced nutrient recycling in a warmer ocean driven by differential response of extracellular enzymatic activities

    KAUST Repository

    Ayo, Begoña

    2017-06-08

    Ocean oligotrophication concurrent with warming weakens the capacity of marine primary producers to support marine food webs and act as a CO2 sink, and is believed to result from reduced nutrient inputs associated to the stabilization of the thermocline. However, nutrient supply in the oligotrophic ocean is largely dependent on the recycling of organic matter. This involves hydrolytic processes catalyzed by extracellular enzymes released by bacteria, which temperature-dependence has not yet been evaluated. Here we report a global assessment of the temperature-sensitivity, as represented by the activation energies (Ea ), of extracellular β-glucosidase (βG), leucine aminopeptidase (LAP) and alkaline phosphatase (AP) enzymatic activities, which enable the uptake by bacteria of substrates rich in carbon, nitrogen and phosphorus, respectively. These Ea were calculated from two different approaches, temperature experimental manipulations and a space-for-time substitution approach, which generated congruent results. The three activities showed contrasting Ea in the subtropical and tropical ocean, with βG increasing the fastest with warming, followed by LAP, while AP showed the smallest increase. The estimated activation energies predict that the hydrolysis products under projected warming scenarios will have higher C:N, C:P and N:P molar ratios than those currently generated, and suggest that the warming of oceanic surface waters leads to a decline in the nutrient supply to the microbial heterotrophic community relative to that of carbon, particularly so for phosphorus, slowing down nutrient recycling and contributing to further ocean oligotrophication. This article is protected by copyright. All rights reserved.

  20. Imbalanced nutrient recycling in a warmer ocean driven by differential response of extracellular enzymatic activities.

    Science.gov (United States)

    Ayo, Begoña; Abad, Naiara; Artolozaga, Itxaso; Azua, Iñigo; Baña, Zuriñe; Unanue, Marian; Gasol, Josep M; Duarte, Carlos M; Iriberri, Juan

    2017-10-01

    Ocean oligotrophication concurrent with warming weakens the capacity of marine primary producers to support marine food webs and act as a CO 2 sink, and is believed to result from reduced nutrient inputs associated to the stabilization of the thermocline. However, nutrient supply in the oligotrophic ocean is largely dependent on the recycling of organic matter. This involves hydrolytic processes catalyzed by extracellular enzymes released by bacteria, which temperature dependence has not yet been evaluated. Here, we report a global assessment of the temperature-sensitivity, as represented by the activation energies (E a ), of extracellular β-glucosidase (βG), leucine aminopeptidase (LAP) and alkaline phosphatase (AP) enzymatic activities, which enable the uptake by bacteria of substrates rich in carbon, nitrogen, and phosphorus, respectively. These E a were calculated from two different approaches, temperature experimental manipulations and a space-for-time substitution approach, which generated congruent results. The three activities showed contrasting E a in the subtropical and tropical ocean, with βG increasing the fastest with warming, followed by LAP, while AP showed the smallest increase. The estimated activation energies predict that the hydrolysis products under projected warming scenarios will have higher C:N, C:P and N:P molar ratios than those currently generated, and suggest that the warming of oceanic surface waters leads to a decline in the nutrient supply to the microbial heterotrophic community relative to that of carbon, particularly so for phosphorus, slowing down nutrient recycling and contributing to further ocean oligotrophication. © 2017 John Wiley & Sons Ltd.

  1. Pretreatment and enzymatic hydrolysis of lignocellulosic biomass

    Science.gov (United States)

    Corredor, Deisy Y.

    The performance of soybean hulls and forage sorghum as feedstocks for ethanol production was studied. The main goal of this research was to increase fermentable sugars' yield through high-efficiency pretreatment technology. Soybean hulls are a potential feedstock for production of bio-ethanol due to their high carbohydrate content (≈50%) of nearly 37% cellulose. Soybean hulls could be the ideal feedstock for fuel ethanol production, because they are abundant and require no special harvesting and additional transportation costs as they are already in the plant. Dilute acid and modified steam-explosion were used as pretreatment technologies to increase fermentable sugars yields. Effects of reaction time, temperature, acid concentration and type of acid on hydrolysis of hemicellulose in soybean hulls and total sugar yields were studied. Optimum pretreatment parameters and enzymatic hydrolysis conditions for converting soybean hulls into fermentable sugars were identified. The combination of acid (H2SO4, 2% w/v) and steam (140°C, 30 min) efficiently solubilized the hemicellulose, giving a pentose yield of 96%. Sorghum is a tropical grass grown primarily in semiarid and dry parts of the world, especially in areas too dry for corn. The production of sorghum results in about 30 million tons of byproducts mainly composed of cellulose, hemicellulose, and lignin. Forage sorghum such as brown midrib (BMR) sorghum for ethanol production has generated much interest since this trait is characterized genetically by lower lignin concentrations in the plant compared with conventional types. Three varieties of forage sorghum and one variety of regular sorghum were characterized and evaluated as feedstock for fermentable sugar production. Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and X-Ray diffraction were used to determine changes in structure and chemical composition of forage sorghum before and after pretreatment and enzymatic hydrolysis

  2. Bacterial cellulose production from cotton-based waste textiles: enzymatic saccharification enhanced by ionic liquid pretreatment.

    Science.gov (United States)

    Hong, Feng; Guo, Xiang; Zhang, Shuo; Han, Shi-fen; Yang, Guang; Jönsson, Leif J

    2012-01-01

    Cotton-based waste textiles were explored as alternative feedstock for production of bacterial cellulose (BC) by Gluconacetobacter xylinus. The cellulosic fabrics were treated with the ionic liquid (IL) 1-allyl-3-methylimidazolium chloride ([AMIM]Cl). [AMIM]Cl caused 25% inactivation of cellulase activity at a concentration as low as of 0.02 g/mL and decreased BC production during fermentation when present in concentrations higher than 0.0005 g/mL. Therefore, removal of residual IL by washing with hot water was highly beneficial to enzymatic saccharification as well as BC production. IL-treated fabrics exhibited a 5-7-fold higher enzymatic hydrolysis rate and gave a seven times larger yield of fermentable sugars than untreated fabrics. BC from cotton cloth hydrolysate was obtained at an yield of 10.8 g/L which was 83% higher than that from the culture grown on glucose-based medium. The BC from G. xylinus grown on IL-treated fabric hydrolysate had a 79% higher tensile strength than BC from glucose-based culture medium which suggests that waste cotton pretreated with [AMIM]Cl has potential to serve as a high-quality carbon source for BC production. Copyright © 2011 Elsevier Ltd. All rights reserved.

  3. Colorimetric determination of nitrate plus nitrite in water by enzymatic reduction, automated discrete analyzer methods

    Science.gov (United States)

    Patton, Charles J.; Kryskalla, Jennifer R.

    2011-01-01

    This report documents work at the U.S. Geological Survey (USGS) National Water Quality Laboratory (NWQL) to validate enzymatic reduction, colorimetric determinative methods for nitrate + nitrite in filtered water by automated discrete analysis. In these standard- and low-level methods (USGS I-2547-11 and I-2548-11), nitrate is reduced to nitrite with nontoxic, soluble nitrate reductase rather than toxic, granular, copperized cadmium used in the longstanding USGS automated continuous-flow analyzer methods I-2545-90 (NWQL laboratory code 1975) and I-2546-91 (NWQL laboratory code 1979). Colorimetric reagents used to determine resulting nitrite in aforementioned enzymatic- and cadmium-reduction methods are identical. The enzyme used in these discrete analyzer methods, designated AtNaR2 by its manufacturer, is produced by recombinant expression of the nitrate reductase gene from wall cress (Arabidopsis thaliana) in the yeast Pichia pastoris. Unlike other commercially available nitrate reductases we evaluated, AtNaR2 maintains high activity at 37°C and is not inhibited by high-phenolic-content humic acids at reaction temperatures in the range of 20°C to 37°C. These previously unrecognized AtNaR2 characteristics are essential for successful performance of discrete analyzer nitrate + nitrite assays (henceforth, DA-AtNaR2) described here.

  4. Hypolipidemic activity of Phellinus rimosus against triton WR-1339 and high cholesterol diet induced hyperlipidemic rats.

    Science.gov (United States)

    Rony, K A; Ajith, T A; Nima, N; Janardhanan, K K

    2014-03-01

    Patients with the risk for atherosclerotic disease will be targeted to reduce the existing hyperlipidemia. The hypolipidemic activity of Phellinus rimosus was studied using triton WR-1339 and high cholesterol diet (HCD) induced models. The triton induced elevated lipid profile was attenuated by P. rimosus or standard drug atorvastatin. Similarly, administration of P. rimosus along with HCD significantly decline serum triglyceride, total cholesterol, low-density lipoprotein, with elevating the high-density lipoprotein. Thiobarbituric acid reacting substances in heart and liver significantly decreased; where as activity of enzymatic antioxidants and level of reduced glutathione were significantly increased. In both models, P. rimosus extract showed a significant ameliorative effect on the elevated atherogenic index as well as LDL/HDL-C ratio. The hypolipidemic activity of P. rimosus can be ascribed to its inhibitory effect on the liver HMG CoA reductase activity. The results suggest the possible therapeutic potential of this fungus as hypolipidemic agent. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Effects of lipids on enzymatic hydrolysis and physical properties of starch.

    Science.gov (United States)

    Ai, Yongfeng; Hasjim, Jovin; Jane, Jay-lin

    2013-01-30

    This study aimed to understand effects of lipids, including corn oil (CO), soy lecithin (SL), palmitic acid (PA), stearic acid (SA), oleic acid (OA), and linoleic acid (LA), on the enzymatic hydrolysis and physical properties of normal corn (NCS), tapioca (TPS), waxy corn (WCS), and high-amylose corn (HA7) starch, and to elucidate mechanisms of interactions between the starches and lipids. After cooking with the lipids (10%, w/w, dsb), NCS, TPS, and HA7 showed significant decreases in enzymatic hydrolysis, and their DSC thermograms displayed amylose-lipid-complex dissociation peaks except with the CO. (13)C NMR spectra of amylodextrin with CO showed downfield changes in the chemical shifts of carbons 1 and 4 of the anhydroglucose unit, indicating helical complex formation. Generally, free fatty acids (FFAs) reduced, but SL increased the peak viscosities of starches. FFAs and SL decreased, but CO increased the gel strength of NCS. These lipids displayed little impacts on the enzymatic hydrolysis and physical properties of WCS because it lacked amylose. Copyright © 2012 Elsevier Ltd. All rights reserved.

  6. Characterization of Amino Acid Profile and Enzymatic Activity in Adult Rat Astrocyte Cultures.

    Science.gov (United States)

    Souza, Débora Guerini; Bellaver, Bruna; Hansel, Gisele; Arús, Bernardo Assein; Bellaver, Gabriela; Longoni, Aline; Kolling, Janaina; Wyse, Angela T S; Souza, Diogo Onofre; Quincozes-Santos, André

    2016-07-01

    Astrocytes are multitasking players in brain complexity, possessing several receptors and mechanisms to detect, participate and modulate neuronal communication. The functionality of astrocytes has been mainly unraveled through the study of primary astrocyte cultures, and recently our research group characterized a model of astrocyte cultures derived from adult Wistar rats. We, herein, aim to characterize other basal functions of these cells to explore the potential of this model for studying the adult brain. To characterize the astrocytic phenotype, we determined the presence of GFAP, GLAST and GLT 1 proteins in cells by immunofluorescence. Next, we determined the concentrations of thirteen amino acids, ATP, ADP, adenosine and calcium in astrocyte cultures, as well as the activities of Na(+)/K(+)-ATPase and acetylcholine esterase. Furthermore, we assessed the presence of the GABA transporter 1 (GAT 1) and cannabinoid receptor 1 (CB 1) in the astrocytes. Cells demonstrated the presence of glutamine, consistent with their role in the glutamate-glutamine cycle, as well as glutamate and D-serine, amino acids classically known to act as gliotransmitters. ATP was produced and released by the cells and ADP was consumed. Calcium levels were in agreement with those reported in the literature, as were the enzymatic activities measured. The presence of GAT 1 was detected, but the presence of CB 1 was not, suggesting a decreased neuroprotective capacity in adult astrocytes under in vitro conditions. Taken together, our results show cellular functionality regarding the astrocytic role in gliotransmission and neurotransmitter management since they are able to produce and release gliotransmitters and to modulate the cholinergic and GABAergic systems.

  7. BSA treatment to enhance enzymatic hydrolysis of cellulose in lignin containing substrates.

    Science.gov (United States)

    Yang, Bin; Wyman, Charles E

    2006-07-05

    Cellulase and bovine serum albumin (BSA) were added to Avicel cellulose and solids containing 56% cellulose and 28% lignin from dilute sulfuric acid pretreatment of corn stover. Little BSA was adsorbed on Avicel cellulose, while pretreated corn stover solids adsorbed considerable amounts of this protein. On the other hand, cellulase was highly adsorbed on both substrates. Adding a 1% concentration of BSA to dilute acid pretreated corn stover prior to enzyme addition at 15 FPU/g cellulose enhanced filter paper activity in solution by about a factor of 2 and beta-glucosidase activity in solution by about a factor of 14. Overall, these results suggested that BSA treatment reduced adsorption of cellulase and particularly beta-glucosidase on lignin. Of particular note, BSA treatment of pretreated corn stover solids prior to enzymatic hydrolysis increased 72 h glucose yields from about 82% to about 92% at a cellulase loading of 15 FPU/g cellulose or achieved about the same yield at a loading of 7.5 FPU/g cellulose. Similar improvements were also observed for enzymatic hydrolysis of ammonia fiber explosion (AFEX) pretreated corn stover and Douglas fir treated by SO(2) steam explosion and for simultaneous saccharification and fermentation (SSF) of BSA pretreated corn stover. In addition, BSA treatment prior to hydrolysis reduced the need for beta-glucosidase supplementation of SSF. The results are consistent with non-specific competitive, irreversible adsorption of BSA on lignin and identify promising strategies to reduce enzyme requirements for cellulose hydrolysis. (c) 2006 Wiley Periodicals, Inc.

  8. Enzymatic Synthesis of Psilocybin.

    Science.gov (United States)

    Fricke, Janis; Blei, Felix; Hoffmeister, Dirk

    2017-09-25

    Psilocybin is the psychotropic tryptamine-derived natural product of Psilocybe carpophores, the so-called "magic mushrooms". Although its structure has been known for 60 years, the enzymatic basis of its biosynthesis has remained obscure. We characterized four psilocybin biosynthesis enzymes, namely i) PsiD, which represents a new class of fungal l-tryptophan decarboxylases, ii) PsiK, which catalyzes the phosphotransfer step, iii) the methyltransferase PsiM, catalyzing iterative N-methyl transfer as the terminal biosynthetic step, and iv) PsiH, a monooxygenase. In a combined PsiD/PsiK/PsiM reaction, psilocybin was synthesized enzymatically in a step-economic route from 4-hydroxy-l-tryptophan. Given the renewed pharmaceutical interest in psilocybin, our results may lay the foundation for its biotechnological production. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Purification and Identification of Antioxidant Peptides from Enzymatic Hydrolysate of Spirulina platensis.

    Science.gov (United States)

    Yu, Jie; Hu, Yuanliang; Xue, Mingxiong; Dun, Yaohao; Li, Shenao; Peng, Nan; Liang, Yunxiang; Zhao, Shumao

    2016-07-28

    The aim of this study was to isolate antioxidant peptides from an enzymatic hydrolysate of Spirulina platensis. A novel antioxidant peptide was obtained by ultrafiltration, gel filtration chromatography, and reverse-phase high-performance liquid chromatography, with the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay used to measure the antioxidant activity, and the sequence was determined to be Pro-Asn-Asn (343.15 Da) by electrospray ionization tandem mass spectrometry. This peptide was synthesized to confirm its antioxidant properties, and it exhibited 81.44 ± 0.43% DPPH scavenging activity at 100 µg/ml, which was similar to that of glutathione (82.63 ± 0.56%). Furthermore, the superoxide anion and hydroxyl free-radical scavenging activities and the SOD activity of the peptide were 47.84 ± 0.49%, 54.01 ± 0.82%, and 12.55 ± 0.75%, respectively, at 10 mg/ml. These results indicate that S. platensis is a good source of antioxidant peptides, and that its hydrolysate may have important applications in the pharmaceutical and food industries.

  10. Cloning, expression, and enzymatic activity evaluation of cholesterol oxidase gene isolated from a native Rhodococcus sp.

    Directory of Open Access Journals (Sweden)

    Hamed Esmaeil Lashgarian

    2016-10-01

    Full Text Available Cholesterol oxidase (CHO is one of the valuable enzymes that play an important role in: measurement of serum cholesterol, food industry as a biocatalyst and agriculture as a biological larvicide. This enzyme was produced by several bacterial strains. Wild type enzyme produced by Rhodococcus sp. secret two forms of CHO enzyme: extra cellular and membrane bound type which its amount is low and unstable. The goal of the study was cloning, expression, and enzymatic activity evaluation of cholesterol oxidase gene isolated from a native Rhodococcus sp. CHO gene was isolated from native bacteria and cloned into pET23a. In the next step, the construct was expressed in E.coli BL21 and induced by different concentration of IPTG ranges from 0.1 - 0.9 mM. This gene contains 1642 bp and encodes a protein consists of 533 amino acids. It has about 96 % homology with CHO gene isolated from Rhodococcus equi. The high expression was obtained in 0.5 mM concentration of IPTG after 4 hour induction. This recombinant enzyme had a molecular weight of 55 kDa, that secretion of intra cellular type is much more than extracellular form. The optimum pH and temperature conditions for the recombinant enzyme were 7.5 and 45°C, respectively. CHO enzyme obtained from Rhodococcus sp. is a cheap enzyme with medical and industrial applications that can be produced easily and purified in large scale with simple methods.

  11. Fabrication and electrochemistry characteristics of nickel-doped diamond-like carbon film toward applications in non-enzymatic glucose detection

    Science.gov (United States)

    Liu, Chi-Wen; Chen, Wei-En; Sun, Yin Tung Albert; Lin, Chii-Ruey

    2018-04-01

    This research work focused on the fabrication of nickel-doped diamond-like carbon (DLC) films and their characteristics including of surface morphology, microstructure, and electrochemical aiming at applications in non-enzymatic glucose detection. Novel nanodiamond target was employed in unbalanced magnetron radio-frequency co-sputtering process to prepared high quality Ni-doped DLC thin film at room temperature. TEM analysis reveals a highly uniform distribution of Ni crystallites in amorphous carbon matrix with fraction ranged from 3 to 11.5 at.% which is considered as active sites for the glucose detection. Our cyclic voltammetry measurements using 0.1 M H2SO4 solution demonstrated that the as-prepared Ni-doped DLC films possess large electrochemical potential window of 2.12 V, and this was also observed to be significantly reduced at high Ni doping level owing to lower sp3 fraction. The non-enzymatic glucose detection investigation indicates that the Ni-doped DLC thin film electrode prepared under 7 W of DC sputtering power on Ni target possesses good detecting performance, high stability, and high sensitivity to glucose concentration up to 10 mM, even with the existence of uric acid and ascorbic acid. The peak current was observed to be proportional to glucose concentration and scanning rate, demonstrating highly reversibility redox process of the film electrode and glucose.

  12. In Situ Enzymatically Generated Photoswitchable Oxidase Mimetics and Their Application for Colorimetric Detection of Glucose Oxidase.

    Science.gov (United States)

    Cao, Gen-Xia; Wu, Xiu-Ming; Dong, Yu-Ming; Li, Zai-Jun; Wang, Guang-Li

    2016-07-09

    In this study, a simple and amplified colorimetric assay is developed for the detection of the enzymatic activity of glucose oxidase (GOx) based on in situ formation of a photoswitchable oxidase mimetic of PO₄(3-)-capped CdS quantum dots (QDs). GOx catalyzes the oxidation of 1-thio-β-d-glucose to give 1-thio-β-d-gluconic acid which spontaneously hydrolyzes to β-d-gluconic acid and H₂S; the generated H₂S instantly reacts with Cd(2+) in the presence of Na₃PO₄ to give PO₄(3-)-stabilized CdS QDs in situ. Under visible-light (λ ≥ 400 nm) stimulation, the PO₄(3-)-capped CdS QDs are a new style of oxidase mimic derived by producing some active species, such as h⁺, (•)OH, O₂(•-) and a little H₂O₂, which can oxidize the typical substrate (3,3,5,5-tetramethylbenzydine (TMB)) with a color change. Based on the GOx-triggered growth of the oxidase mimetics of PO₄(3-)-capped CdS QDs in situ, we developed a simple and amplified colorimetric assay to probe the enzymatic activity of GOx. The proposed method allowed the detection of the enzymatic activity of GOx over the range from 25 μg/L to 50 mg/L with a low detection limit of 6.6 μg/L. We believe the PO₄(3-)-capped CdS QDs generated in situ with photo-stimulated enzyme-mimicking activity may find wide potential applications in biosensors.

  13. Enzymatic transesterification of waste vegetable oil to produce biodiesel.

    Science.gov (United States)

    Lopresto, C G; Naccarato, S; Albo, L; De Paola, M G; Chakraborty, S; Curcio, S; Calabrò, V

    2015-11-01

    An experimental study on enzymatic transesterification was performed to produce biodiesel from waste vegetable oils. Lipase from Pseudomonas cepacia was covalently immobilized on a epoxy-acrylic resin support. The immobilized enzyme exhibited high catalytic specific surface and allowed an easy recovery, regeneration and reutilisation of biocatalyst. Waste vegetable oils - such as frying oils, considered not competitive with food applications and wastes to be treated - were used as a source of glycerides. Ethanol was used as a short chain alcohol and was added in three steps with the aim to reduce its inhibitory effect on lipase activity. The effect of biocatalyst/substrate feed mass ratios and the waste oil quality have been investigated in order to estimate the process performances. Biocatalyst recovery and reuse have been also studied with the aim to verify the stability of the biocatalyst for its application in industrial scale. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Operation and Control of Enzymatic Biodiesel Production

    DEFF Research Database (Denmark)

    Price, Jason Anthony; Huusom, Jakob Kjøbsted; Nordblad, Mathias

    This work explores the control of biodiesel production via an enzymatic catalyst. The process involves the transesterification of oils/fats with an alcohol (usually methanol or ethanol), using enzymatic catalysts to generate mono-alkyl esters (the basis of biodiesel) and glycerol as by......-product. Current literature indicates that enzymatic processing of oils and fats to produce biodiesel is technically feasible and developments in immobilization technology indicate that enzyme catalysts can become cost effective compared to chemical processing. However, with very few exceptions, enzyme technology...... is not currently used in commercial-scale biodiesel production. This is mainly due to non-optimized process designs, which do not use the full potential of the catalysts in a cost-efficient way. Furthermore is it unclear what process variables need to be monitored and controlled to ensure optimal economics...

  15. Antioxidant Enzyme Activities of some Brassica Species

    Directory of Open Access Journals (Sweden)

    Rodica SOARE

    2017-11-01

    Full Text Available This paper set out to comparatively study five species: white cabbage (Brassica oleracea L. var. capitata alba Alef., red cabbage (Brassica oleracea L. var. capitata f. rubra Alef., Kale (Brassica oleracea L. var. Acephala, cauliflower (Brassica oleracea var. botrytis and broccoli (Brassica oleracea var. cymosa in order to identify those with high enzymatic and antioxidant activities. The enzymatic activity of superoxide dismutase (SOD, catalase (CAT and soluble peroxidase (POX as well as the antioxidant activity against 2.2’-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid (ABTS radical cation were determined. Total superoxide dismutase activity was measured spectrophotometrically based on inhibition in the photochemical reduction of nitroblue tetrazolium. Total soluble peroxidase was assayed by measuring the increase in A436 due to the guaiacol oxidation and the catalase activity was assayed through the colorimetric method. The capacity of extracts to scavenge the ABTS radical cation was assessed colorimetric using Trolox as a standard. The obtained results show that studied enzymatic activities and the antioxidant activity against ABTS vary depending on the analyzed species. So, among the studied Brassicaceae species, it emphasize red cabbage with the highest enzymatic activity (CAT 22.54 mM H2O2/min/g and POX 187.2 mM ΔA/1min/1g f.w. and kale with highest antioxidant activity, of 767 μmol TE/100g f.w. The results of this study recommendintroducing the studied varieties in diet due to the rich antioxidant properties.

  16. Similar potential ATP-P production and enzymatic activities in the microplankton community off Concepción (Chile) under oxic and suboxic conditions

    Science.gov (United States)

    González, Rodrigo R.; Gutiérrez, Marcelo H.; Quiñones, Renato A.

    2007-11-01

    The effects of the oxygen minimum zone on the metabolism of the heterotrophic microplankton community (0.22-100 μm) in the Humboldt Current System, as well as the factors controlling its biomass production, remain unknown. Here we compare the effect of four sources of dissolved organic carbon (glucose, oxaloacetate, glycine, leucine) on microbial biomass production (such as ATP-P) and the potential enzymatic activities involved in catabolic pathways under oxic and suboxic conditions. Our results show significant differences ( p oxygen minimum zone has the same or greater potential growth than the community inhabiting more oxygenated strata of the water column and that malate dehydrogenase is the activity that best represents the metabolic potential of the community.

  17. Protective effects against H2O2-induced damage by enzymatic hydrolysates of an edible brown seaweed, sea tangle (Laminaria japonica).

    Science.gov (United States)

    Park, Pyo-Jam; Kim, Eun-Kyung; Lee, Seung-Jae; Park, Sun-Young; Kang, Dong-Soo; Jung, Bok-Mi; Kim, Kui-Shik; Je, Jae-Young; Ahn, Chang-Bum

    2009-02-01

    Enzymatic hydrolysates of Laminaria japonica were evaluated for antioxidative activities using hydroxyl radical scavenging activity and protective effects against H(2)O(2)-induced DNA and cell damage. In addition, activities of antioxidative enzymes, including catalase, glutathione peroxidase, and glutathione S-transferase, of the enzymatic hydrolysates from L. japonica were also estimated. L. japonica was first enzymatically hydrolyzed by seven carbohydrases (Dextrozyme, AMG, Promozyme, Maltogenase, Termamyl, Viscozyme, and Celluclast [all from Novo Co., Novozyme Nordisk, Bagsvaerd, Denmark]) and five proteinases (Flavourzyme, Neutrase, Protamex, Alcalase [all from Novo Co.], and pancreatic trypsin). The hydroxyl radical scavenging activities of Promozyme and pancreatic trypsin hydrolysates from L. japonica were the highest as compared to those of the other carbohydrases and proteinases, and their 50% inhibitory concentration values were 1.67 and 317.49 mug/mL, respectively. The pancreatic trypsin hydrolysates of L. japonica exerted a protective effect on H(2)O(2)-induced DNA damage. We also evaluated the protective effect on hydroxyl radical-induced oxidative damage in PC12 cells via propidium iodide staining using a flow cytometer. The AMG and pancreatic trypsin hydrolysates of L. japonica dose-dependently protected PC12 cells against cell death caused by hydroxyl radical-induced oxidative damage. Additionally, we analyzed the activity of antioxidative enzymes such as catalase, glutathione peroxidase, and the phase II biotransformation enzyme glutathione S-transferase in L. japonica-treated cells. The activity of all antioxidative enzymes was higher in L. japonica-treated cells compared with the nontreated cells. These results indicate that enzymatic hydrolysates of L. japonica possess antioxidative activity.

  18. Enzymatically crosslinked silk-hyaluronic acid hydrogels.

    Science.gov (United States)

    Raia, Nicole R; Partlow, Benjamin P; McGill, Meghan; Kimmerling, Erica Palma; Ghezzi, Chiara E; Kaplan, David L

    2017-07-01

    In this study, silk fibroin and hyaluronic acid (HA) were enzymatically crosslinked to form biocompatible composite hydrogels with tunable mechanical properties similar to that of native tissues. The formation of di-tyrosine crosslinks between silk fibroin proteins via horseradish peroxidase has resulted in a highly elastic hydrogel but exhibits time-dependent stiffening related to silk self-assembly and crystallization. Utilizing the same method of crosslinking, tyramine-substituted HA forms hydrophilic and bioactive hydrogels that tend to have limited mechanics and degrade rapidly. To address the limitations of these singular component scaffolds, HA was covalently crosslinked with silk, forming a composite hydrogel that exhibited both mechanical integrity and hydrophilicity. The composite hydrogels were assessed using unconfined compression and infrared spectroscopy to reveal of the physical properties over time in relation to polymer concentration. In addition, the hydrogels were characterized by enzymatic degradation and for cytotoxicity. Results showed that increasing HA concentration, decreased gelation time, increased degradation rate, and reduced changes that were observed over time in mechanics, water retention, and crystallization. These hydrogel composites provide a biologically relevant system with controllable temporal stiffening and elasticity, thus offering enhanced tunable scaffolds for short or long term applications in tissue engineering. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Modification of enzymes by use of high-pressure homogenization.

    Science.gov (United States)

    Dos Santos Aguilar, Jessika Gonçalves; Cristianini, Marcelo; Sato, Helia Harumi

    2018-07-01

    High-pressure is an emerging and relatively new technology that can modify various molecules. High-pressure homogenization (HPH) has been used in several studies on protein modification, especially in enzymes used or found in food, from animal, plant or microbial resources. According to the literature, the enzymatic activity can be modulated under pressure causing inactivation, stabilization or activation of the enzymes, which, depending on the point of view could be very useful. Homogenization can generate changes in the structure of the enzyme modifying various chemical bonds (mainly weak bonds) causing different denaturation levels and, consequently, affecting the catalytic activity. This review aims to describe the various alterations due to HPH treatment in enzymes, to show the influence of high-pressure on proteins and to report the HPH effects on the enzymatic activity of different enzymes employed in the food industry and research. Copyright © 2018 Elsevier Ltd. All rights reserved.

  20. Glucose obtained from rice bran by ultrasound-assisted enzymatic hydrolysis

    Directory of Open Access Journals (Sweden)

    Raquel Cristine Kuhn

    2015-05-01

    Full Text Available In this work ultrasound-assisted solid-state enzymatic hydrolysis of rice bran to obtain fermentable sugars was investigated. For this purpose, process variables such as temperature, enzyme concentration and moisture content were evaluated during the enzymatic hydrolysis with and without ultrasound irradiation. The enzyme used is a blend of amylases derived from genetically modified strains of Trichoderma reesei. Kinetic of the enzymatic hydrolysis of rice bran at the constant-reaction rate period were measured. The best results for the ultrasound-assisted enzymatic hydrolysis was obtained using 3 wt% of enzyme, 60 oC and moisture content of 65 wt%, yielding 0.38 g sugar/g rice bran, whereas for the hydrolysis in the absence of ultrasound the highest yield was 0.20 g sugar/g rice bran using 3 wt% of enzyme, 60 oC and moisture content of 50 wt%. The use of ultrasound-assisted enzymatic hydrolysis of rice bran was intensified, obtaining around 74% more fermentable sugar than in the absence, showing that the use of ultrasound is a promising technology to be used in enzymatic reaction as an alternative of process intensification.

  1. Pregnancy Exercise Increase Enzymatic Antioxidant In Pregnant Women

    Directory of Open Access Journals (Sweden)

    Wagey Freddy Wagey

    2012-01-01

    Full Text Available Objectives: Pregnancy is a vulnerable condition to all kinds of "stress", resulting in changes of physiological and metabolic functions. This research aims to determine effect of exercise during pregnancy in increasing enzymatic antioxidant marked by increase of superoxide dismutase (SOD, gluthation peroxidase (GSHPx, and catalase (CAT levels. Methods: Randomized pre and posttest control group design was employed in this study. A number of 66 pregnant women were recruited in this study and grouped into two groups, i.e 30 of them as control group and the rest as treatment group. Pregnancy exercise was performed to all 36 pregnant women from 20 weeks gestation on treatment group. The exercise was performed in the morning for about 30 minutes, twice a weeks. On the other hand, daily activities was sugested for control group. Student’s t-test was then applied to determine the mean different of treatment and control group with 5 % of significant value. Results: This study reveals that there were significantly higher increase of (superoxide dismutase (SOD, gluthation peroxidase (GSHPx, and catalse (CAT levels of treatment group compare to control group. These enzymatic antioxidant increase among these two group were around 1.36 mg/gHb for SOD; 1.14 IU/gHb for GSHPx; and 0.97 IU/gHb for CAT, (p < 0.05.  Clinical outcomes, such as strengten of pelvic muscle and quality of life of treatment group were significantly better compared to control group (p < 0.05. Conclusions: This means that exercise during pregnancy ages of 20 weeks increase enzymatic antioxidant levels SOD, GSHPx, and CAT higher compare to control group without exercise.  

  2. Pregnancy Exercise Increase Enzymatic Antioxidant In Pregnant Women

    Directory of Open Access Journals (Sweden)

    Wagey Freddy Wagey

    2012-01-01

    Full Text Available Objectives: Pregnancy is a vulnerable condition to all kinds of "stress", resulting in changes of physiological and metabolic functions. This research aims to determine effect of exercise during pregnancy in increasing enzymatic antioxidant marked by increase of superoxide dismutase (SOD, gluthation peroxidase (GSHPx, and catalase (CAT levels. Methods: Randomized pre and posttest control group design was employed in this study. A number of 66 pregnant women were recruited in this study and grouped into two groups, i.e 30 of them as control group and the rest as treatment group. Pregnancy exercise was performed to all 36 pregnant women from 20 weeks gestation on treatment group. The exercise was performed in the morning for about 30 minutes, twice a weeks. On the other hand, daily activities was sugested for control group. Student’s t-test was then applied to determine the mean different of treatment and control group with 5 % of significant value. Results: This study reveals that there were significantly higher increase of (superoxide dismutase (SOD, gluthation peroxidase (GSHPx, and catalse (CAT levels of treatment group compare to control group. These enzymatic antioxidant increase among these two group were around 1.36 mg/gHb for SOD; 1.14 IU/gHb for GSHPx; and 0.97 IU/gHb for CAT, (p < 0.05. Clinical outcomes, such as strengten of pelvic muscle and quality of life of treatment group were significantly better compared to control group (p < 0.05. Conclusions: This means that exercise during pregnancy ages of 20 weeks increase enzymatic antioxidant levels SOD, GSHPx, and CAT higher compare to control group without exercise.

  3. Enzymatic hydrolysis (pepsin assisted by ultrasound in the functional Properties of hydrolyzates from different collagens

    Directory of Open Access Journals (Sweden)

    Alessandra Roseline Vidal

    2018-03-01

    Full Text Available ABSTRACT: Enzymatic hydrolysis (pepsin assisted with or without ultrasound in the functional properties of hydrolyzates from different collagens were analyzed. Degree of hydrolysis, antioxidant activity (DPPH and antimicrobial activity (MIC were assessed. The treatment that resulted in greater antioxidant activity for the fiber sample was with the use of 4% of enzyme and concomitant ultrasound (40.7%, leading to a degree of hydrolysis of 21.7%. For the powdered fiber sample the hydrolysis treatment with use of 4% of enzyme resulted in lower protein content (6.97mg/mL, higher degree of hydrolysis (19.9% and greater antioxidant activity (38.6%. The hydrolyzates showed inhibitory capacity against gram-negative bacteria Salmonella choleraesuis and gram-positive bacteria Staphylococcus aureus. It can be concluded that enzymatic hydrolysis concomitant or not with the use of ultrasound increased the functionality of the fiber and powdered fiber samples, for the other samples its use as supplementary treatment was not productive, due to the worse results of antioxidant activity (DPPH reported. However, it provided greater hydrolysis degree.

  4. Enzymatic formulation capable of degrading scrapie prion under mild digestion conditions.

    Directory of Open Access Journals (Sweden)

    Emeka A Okoroma

    Full Text Available The prion agent is notoriously resistant to common proteases and conventional sterilisation procedures. The current methods known to destroy prion infectivity such as incineration, alkaline and thermal hydrolysis are harsh, destructive, environmentally polluting and potentially hazardous, thus limit their applications for decontamination of delicate medical and laboratory devices, remediation of prion contaminated environment and for processing animal by-products including specified risk materials and carcases. Therefore, an environmentally friendly, non-destructive enzymatic degradation approach is highly desirable. A feather-degrading Bacillus licheniformis N22 keratinase has been isolated which degraded scrapie prion to undetectable level of PrP(Sc signals as determined by Western Blot analysis. Prion infectivity was verified by ex vivo cell-based assay. An enzymatic formulation combining N22 keratinase and biosurfactant derived from Pseudomonas aeruginosa degraded PrP(Sc at 65 °C in 10 min to undetectable level -. A time-course degradation analysis carried out at 50 °C over 2 h revealed the progressive attenuation of PrP(Sc intensity. Test of residual infectivity by standard cell culture assay confirmed that the enzymatic formulation reduced PrP(Sc infectivity to undetectable levels as compared to cells challenged with untreated standard scrapie sheep prion (SSBP/1 (p-value = 0.008 at 95% confidence interval. This novel enzymatic formulation has significant potential application for prion decontamination in various environmentally friendly systems under mild treatment conditions.

  5. Enzymatic process development for the extraction of ferulic from wheat bran [abstract

    Directory of Open Access Journals (Sweden)

    Blecker, C.

    2010-01-01

    sufficient to eliminate part of the starch (wheat bran starch granules are usually about 20 µm. Purified FAE are still not commercially available. However, several enzyme complexes do present FAE activity: Depol™ 740 l (Biocatalysts, Pentopan™ 500 BG and Novo™ 188 (Novozymes, Pectinase™ PE (Catalysts, Grindamyl™ S100 (Danisco, etc. These complexes are used as filtration aid or for bread making. FAE activity is usually a side activity, the major being hemicellulase and cellulase, except for Depol™ 740 l in which FAE activity is standardized (36 U.g-1. Even though it should be preferably integrated in a wider industrial scheme, a high potential of wheat bran valorization lies in the field of natural antioxidants extraction.

  6. An investigation of nitrile transforming enzymes in the chemo-enzymatic synthesis of the taxol sidechain.

    Science.gov (United States)

    Wilding, Birgit; Veselá, Alicja B; Perry, Justin J B; Black, Gary W; Zhang, Meng; Martínková, Ludmila; Klempier, Norbert

    2015-07-28

    Paclitaxel (taxol) is an antimicrotubule agent widely used in the treatment of cancer. Taxol is prepared in a semisynthetic route by coupling the N-benzoyl-(2R,3S)-3-phenylisoserine sidechain to the baccatin III core structure. Precursors of the taxol sidechain have previously been prepared in chemoenzymatic approaches using acylases, lipases, and reductases, mostly featuring the enantioselective, enzymatic step early in the reaction pathway. Here, nitrile hydrolysing enzymes, namely nitrile hydratases and nitrilases, are investigated for the enzymatic hydrolysis of two different sidechain precursors. Both sidechain precursors, an openchain α-hydroxy-β-amino nitrile and a cyanodihydrooxazole, are suitable for coupling to baccatin III directly after the enzymatic step. An extensive set of nitrilases and nitrile hydratases was screened towards their activity and selectivity in the hydrolysis of two taxol sidechain precursors and their epimers. A number of nitrilases and nitrile hydratases converted both sidechain precursors and their epimers.

  7. Kinetics of enzymatic hydrolysis of methyl ricinoleate

    OpenAIRE

    Neeharika, T. S.V.R.; Lokesh, P.; Prasanna Rani, K. N.; Prathap Kumar, T.; Prasad, R. B.N.

    2015-01-01

    Ricinoleic acid is an unsaturated hydroxy fatty acid that naturally occurs in castor oil in proportions of up to 85–90%. Ricinoleic acid is a potential raw material and finds several applications in coatings, lubricant formulations and pharmaceutical areas. Enzymatic hydrolysis of castor oil is preferred over conventional hydrolysis for the preparation of ricinoleic acid to avoid estolide formation. A kinetics analysis of the enzymatic hydrolysis of Methyl Ricinoleate in the presence of Candi...

  8. [The effect of enzymatic treatment using proteases on properties of persistent sodium current in CA1 pyramidal neurons of rat hippocampus].

    Science.gov (United States)

    Lun'ko, O O; Isaiev, D S; Maxymiuk, O P; Kryshtal', O O; Isaieva, O V

    2014-01-01

    We investigated the effect of proteases, widely used for neuron isolation in electrophysiological studies, on the amplitude and kinetic characteristics of persistent sodium current (I(NaP)) in hippocampal CA1 pyramidal neurons. Properties of I(NaP) were studied on neurons isolated by mechanical treatment (control group) and by mechanical and enzymatic treatment using pronase E (from Streptomyces griseus) or protease type XXIII (from Aspergillus oryzae). We show that in neurons isolated with pronase E kinetic of activation and density of I(NaP) was unaltered. Enzymatic treatment with protease type XXIII did not alter I(NaP) activation but result in significant decrease in I(NaP) density. Our data indicates that enzymatic treatment using pronase E for neuron isolation is preferable for investigation of I(NaP).

  9. Recycle of enzymes and substrate following enzymatic hydrolysis of steam-pretreated aspenwood

    Energy Technology Data Exchange (ETDEWEB)

    Mes-Hartree, M.; Hogan, C.M.; Saddler, J.N.

    1987-09-01

    The commercial production of chemicals and fuels from lignocellulosic residues by enzymatic means still requires considerable research on both the technical and economic aspects. Two technical problems that have been identified as requiring further research are the recycle of the enzymes used in hydrolysis and the reuse of the recalcitrant cellulose remaining after incomplete hydrolysis. Enzyme recycle is required to lower the cost of the enzymes, while the reuse of the spent cellulose will lower the feedstock cost. The conversion process studied was a combined enzymatic hydrolysis and fermentation (CHF) procedure that utilized the cellulolytic enzymes derived from the fungus Trichoderma harzianum E58 and the yeast Saccharomyces cerevisiae. The rate and extent of hydrolysis and ethanol production was monitored as was the activity and hydrolytic potential of the enzymes remaining in the filtrate after the hydrolysis period. When a commercial cellulose was used as the substrate for a routine 2-day CHF process, 60% of the original filter paper activity could be recovered. When steam-treated, water-extracted aspenwood was used as the substrate, only 13% of the original filter paper activity was detected after a similar procedure. The combination of 60% spent enzymes with 40% fresh enzymes resulted in the production of 30% less reducing sugars than the original enzyme mixture. Since 100% hydrolysis of the cellulose portion is seldom accomplished in an enzymatic hydrolysis process, the residual cellulose was used as a substrate for the growth of T. harzianum E58 and production of cellulolytic enzymes. The residue remaining after the CHF process was used as a substrate for the production of the cellulolytic enzymes. The production of enzymes from the residue of the Solka Floc hydrolysis was greater than the production of enzymes from the original Solka Floc. (Refs. 14).

  10. Enzymatic and acidic degradation of high molecular weight dextran into low molecular weight and its characterizations using novel Diffusion-ordered NMR spectroscopy.

    Science.gov (United States)

    Iqbal, Samina; Marchetti, Roberta; Aman, Afsheen; Silipo, Alba; Qader, Shah Ali Ul; Molinaro, Antonio

    2017-10-01

    Low molecular weight fractions were derived from native high molecular weight dextran produced by Leuconostoc mesenteroides KIBGE-IB26. Structural characterization of native and low molecular weight fractions obtained after acidic and enzymatic hydrolysis was done using FTIR and NMR spectroscopy. The molecular weight was estimated using Diffusion Ordered NMR spectroscopy. Native dextran (892kDa) is composed of α-(1→6) glycosidic linkage along with α-(1→3) branching. Major proportion of 528kDa dextran was obtained after prolong enzymatic hydrolysis however, an effective acidic treatment at pH-1.4 up to 02 and 04h of exposure resulted in the formation of 77kDa and 57kDa, respectively. The increment in pH from 1.4 to 1.8 lowered the hydrolysis efficiency and resulted in the formation of 270kDa dextran fraction. The results suggest that derived low molecular weight water soluble fractions can be utilized as a drug delivery carrier along with multiple application relating pharmaceutical industries. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Enzymatic properties of the glycine D-alanine [corrected] aminopeptidase of Aspergillus oryzae and its activity profiles in liquid-cultured mycelia and solid-state rice culture (rice koji).

    Science.gov (United States)

    Marui, Junichiro; Matsushita-Morita, Mayumi; Tada, Sawaki; Hattori, Ryota; Suzuki, Satoshi; Amano, Hitoshi; Ishida, Hiroki; Yamagata, Youhei; Takeuchi, Michio; Kusumoto, Ken-Ichi

    2012-01-01

    The gdaA gene encoding S12 family glycine-D-alanine aminopeptidase (GdaA) was found in the industrial fungus Aspergillus oryzae. GdaA shares 43% amino acid sequence identity with the D-aminopeptidase of the Gram-negative bacterium Ochrobactrum anthropi. GdaA purified from an A. oryzae gdaA-overexpressing strain exhibited high D-stereospecificity and efficiently released N-terminal glycine and D-alanine of substrates in a highly specific manner. The optimum pH and temperature were 8 to 9 and 40°C, respectively. This enzyme was stable under alkaline conditions at pH 8 to 11 and relatively resistant to acidic conditions until pH 5.0. The chelating reagent EDTA, serine protease inhibitors such as AEBSF, benzamidine, TPCK, and TLCK, and the thiol enzyme inhibitor PCMB inhibited the enzyme. The aminopeptidase inhibitor bestatin did not affect the activity. GdaA was largely responsible for intracellular glycine and D-alanine aminopeptidase activities in A. oryzae during stationary-phase growth in liquid media. In addition, the activity increased in response to the depletion of nitrogen or carbon sources in the growth media, although the GdaA-independent glycine aminopeptidase activity highly increased simultaneously. Aminopeptidases of A. oryzae attract attention because the enzymatic release of a variety of amino acids and peptides is important for the enhancement of the palatability of fermented foods. GdaA activity was found in extracts of a solid-state rice culture of A. oryzae (rice koji), which is widely used as a starter culture for Japanese traditional fermented foods, and was largely responsible for the glycine and D-alanine aminopeptidase activity detected at a pH range of 6 to 9.

  12. Enzymatic activity of proteases and its isoenzymes in fermentation process in cultivars of cocoa (Theobroma cacao L. produced in southern Bahia, Brazil

    Directory of Open Access Journals (Sweden)

    Luciane Santos SOUSA

    Full Text Available Abstract The fermentation of cocoa seeds envolves microbial processes and the action of enzymes. To identify the possible differences in the cocoa fermentation process, with regards to proteolysis, this study has the objective of determining protease activity (under predetermined conditions and its isoenzymes in two cocoa cultivars (PH-16 and HRT-1188 in different cocoa fermentation times, in addition to establishing the microbial load (molds and yeasts and aerobic mesophilic. Protease and its isoenzymes were extracted and partially purified and the enzymatic activities determined by spectrophotometry. The results showed that the proteases activity was higher at 66h of fermentation for both cultivars. When the isoenzymes activity was evaluated, the results demonstrated similar activity behavior for both cultivars, with regards to the isoenzymes aminopeptidase and carboxypeptidase, although the behavior of the endoprotease isoenzyme activity proved to be a little different for TSH-1188 cultivar. Concerning microbiological analyses, the results indicate that the period after molds and yeast counting reduction is consistent with the period of protease activity increase.

  13. Enzymatic network for production of ether amines from alcohols

    NARCIS (Netherlands)

    Palacio, Cyntia M.; Crismaru, Gica Ciprian; Bartsch, Sebastian; Navickas, Vaidotas; Ditrich, Klaus; Breuer, Michael; Abu, Rohana; Woodley, John; Baldenius, Kai-Uwe; Wu, Bian; Janssen, Dick

    We constructed an enzymatic network composed of three different enzymes for the synthesis of valuable ether amines. The enzymatic reactions are interconnected to catalyze the oxidation and subsequent transamination of the substrate and to provide cofactor recycling. This allows production of the

  14. Aldehyde PEGylation of laccase from Trametes versicolor in route to increase its stability: effect on enzymatic activity.

    Science.gov (United States)

    Mayolo-Deloisa, Karla; González-González, Mirna; Simental-Martínez, Jesús; Rito-Palomares, Marco

    2015-03-01

    Laccase is a multicopper oxidase that catalyzes the oxidation of phenolic compounds. Laccase can be used in bioremediation, beverage (wine, fruit juice, and beer) processing, ascorbic acid determination, sugar beet pectin gelation baking, and as a biosensor. Recently, the antiproliferative activity of laccase toward tumor cells has been reported. Because of the potential applications of this enzyme, the efforts for enhancing and stabilizing its activity have increased. Thus, the PEGylation of laccase can be an alternative. PEGylation is the covalent attachment of one or more molecules of methoxy poly(ethylene glycol) (mPEG) to a protein. Normally, during the PEGylation reaction, the activity is reduced but the stability increases; thus, it is important to minimize the loss of activity. In this work, the effects of molar ratio (1:4, 1:8, and 1:12), concentration of laccase (6 and 12 mg/ml), reaction time (4 and 17 h), molecular weight, and type of mPEG (20, 30, 40 kDa and 40 kDa-branched) were analyzed. The activity was measured using three substrates: ABTS, 2,6-dimethoxyphenol, and syringaldazine. The best conditions for laccase PEGylation were 12 mg/ml of laccase, molar ratio 1:4, and 4 h reaction time. Under these conditions, the enzyme was able to maintain nearly 100% of its enzymatic activity with ABTS. The PEGylation of laccase has not been extensively explored, so it is important to analyze the effects of this bioconjugation in route to produce a robust modified enzyme. Copyright © 2015 John Wiley & Sons, Ltd.

  15. Recent insights in enzymatic synthesis of fructooligosaccharides from inulin.

    Science.gov (United States)

    Singh, Ram Sarup; Singh, Rupinder Pal; Kennedy, John F

    2016-04-01

    In the past few years, people are paying more attention to their dietary habits, and functional foods are playing a key role in maintaining the health of man. Prebiotics are considered as a main component of the functional foods which are usually composed of short chains of carbohydrates. Fructooligosaccharides (FOSs) are considered as one of the main group of prebiotics which have recognisable bifidogenic properties. FOSs are obtained either by extraction from various plant materials or by enzymatic synthesis from different substrates. Enzymatically, these can be obtained either from sucrose using fructosyltransferase or from inulin by endoinulinase. Inulin is a potent substrate for the enzymatic production of FOSs. This review article will provide an overview on the inulin as potent substrate, microbial sources of endoinulinases, enzymatic synthesis of FOSs from inulin, commercial status of FOSs, and their future perspectives. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Dissipation of S-metolachlor in plant and soil and effect on enzymatic activities.

    Science.gov (United States)

    Wołejko, Elżbieta; Kaczyński, Piotr; Łozowicka, Bożena; Wydro, Urszula; Borusiewicz, Andrzej; Hrynko, Izabela; Konecki, Rafał; Snarska, Krystyna; Dec, Dorota; Malinowski, Paweł

    2017-07-01

    The present study aimed at evaluating the dissipation of S-metolachlor (S-MET) at three doses in maize growing on diverse physico-chemical properties of soil. The effect of herbicide on dehydrogenase (DHA) and acid phosphatase (ACP) activity was estimated. A modified QuEChERS method using LC-MS/MS has been developed. The limit of quantification (0.001 mg kg -1 ) and detection (0.0005 mg kg -1 ) were very low for soil and maize samples. The mean recoveries and RSDs for the six spiked levels (0.001-0.5 mg kg -1 ) were 91.3 and 5.8%. The biggest differences in concentration of S-MET in maize were observed between the 28th and 63rd days. The dissipation of S-MET in the alkaline soil was the slowest between the 2nd and 7th days, and in the acidic soil between the 5th and 11th days. DT 50 of S-MET calculated according to the first-order kinetics model was 11.1-14.7 days (soil) and 9.6-13.9 days (maize). The enzymatic activity of soil was higher in the acidic environment. One observed the significant positive correlation of ACP with pH of soil and contents of potassium and magnesium and negative with contents of phosphorus and organic carbon. The results indicated that at harvest time, the residues of S-MET in maize were well below the safety limit for maize. The findings of this study will foster the research on main parameters influencing the dissipation in maize ecosystems.

  17. Optimization of enzymatic hydrolysis of guar gum using response surface methodology.

    Science.gov (United States)

    Mudgil, Deepak; Barak, Sheweta; Khatkar, B S

    2014-08-01

    Guar gum is a polysaccharide obtained from guar seed endosperm portion. Enzymatically hydrolyzed guar gum is low in viscosity and has several health benefits as dietary fiber. In this study, response surface methodology was used to determine the optimum conditions for hydrolysis that give minimum viscosity of guar gum. Central composite was employed to investigate the effects of pH (3-7), temperature (20-60 °C), reaction time (1-5 h) and cellulase concentration (0.25-1.25 mg/g) on viscosity during enzymatic hydrolysis of guar (Cyamopsis tetragonolobus) gum. A second order polynomial model was developed for viscosity using regression analysis. Results revealed statistical significance of model as evidenced from high value of coefficient of determination (R(2) = 0.9472) and P < 0.05. Viscosity was primarily affected by cellulase concentration, pH and hydrolysis time. Maximum viscosity reduction was obtained when pH, temperature, hydrolysis time and cellulase concentration were 6, 50 °C, 4 h and 1.00 mg/g, respectively. The study is important in optimizing the enzymatic process for hydrolysis of guar gum as potential source of soluble dietary fiber for human health benefits.

  18. Quantification and characterization of enzymatically produced hyaluronan with fluorophore-assisted carbohydrate electrophoresis

    NARCIS (Netherlands)

    Kooy, F.K.; Muyuan Ma,; Beeftink, H.H.; Eggink, G.; Tramper, J.; Boeriu, C.G.

    2009-01-01

    Hyaluronan (HA) is a polysaccharide with high-potential medical applications, depending on the chain length and the chain length distribution. Special interest goes to homogeneous HA oligosaccharides, which can be enzymatically produced using Pasteurella multocida hyaluronan synthase (PmHAS). We

  19. Enzymatic analysis of Hemiscorpius lepturus scorpion venom using zymography and venom-specific antivenin.

    Science.gov (United States)

    Seyedian, Ramin; Pipelzadeh, Mohammad Hassan; Jalali, Amir; Kim, Euikyung; Lee, Hyunkyoung; Kang, Changkeun; Cha, Mijin; Sohn, Eun-Tae; Jung, Eun-Sun; Rahmani, Ali Hassan; Mirakabady, Abbas Zare

    2010-09-15

    Hemiscorpius lepturus envenomation exhibits various pathological changes in the affected tissues, including skin, blood cells, cardiovascular and central nervous systems. The enzymatic activity and protein component of the venom have not been described previously. In the present study, the electrophoretic profile of H. lepturus venom was determined by SDS-PAGE (12 and 15%), resulting in major protein bands at 3.5-5, 30-35 and 50-60 kDa. The enzymatic activities of the venom was, for the first time, investigated using various zymography techniques, which showed the gelatinolytic, caseinolytic, and hyaluronidase activities mainly at around 50-60 kDa, 30-40 kDa, and 40-50 kDa, respectively. Among these, the proteolytic activities was almost completely disappeared in the presence of a matrix metalloproteinase inhibitor, 1, 10-phenanthroline. Antigen-antibody interactions between the venom and its Iranian antivenin was observed by Western blotting, and it showed several antigenic proteins in the range of 30-160 kDa. This strong antigen-antibody reaction was also demonstrated through an enzyme-linked immunosorbent assay (ELISA). The gelatinase activity of the venom was suppressed by Razi institute polyvalent antivenin, suggesting the inhibitory effect of the antivenin against H. lepturus venom protease activities. Prudently, more extensive clinical studies are necessary for validation of its use in envenomed patients. Copyright 2010 Elsevier Ltd. All rights reserved.

  20. Covalent immobilization of porcine pancreatic lipase on carboxyl-activated magnetic nanoparticles: Characterization and application for enzymatic inhibition assays

    International Nuclear Information System (INIS)

    Zhu, Yuan-Ting; Ren, Xiao-Yun; Liu, Yi-Ming; Wei, Ying; Qing, Lin-Sen; Liao, Xun

    2014-01-01

    Using carboxyl functionalized silica-coated magnetic nanoparticles (MNPs) as carrier, a novel immobilized porcine pancreatic lipase (PPL) was prepared through the 1-ethyl-3-[3-dimethylaminopropyl] carbodiimide hydrochloride/N-hydroxysuccinimide (EDC/NHS) coupling reaction. Transmission electron microscopic images showed that the synthesized nanoparticles (Fe 3 O 4 –SiO 2 ) possessed three dimensional core–shell structures with an average diameter of ∼ 20 nm. The effective enzyme immobilization onto the nanocomposite was confirmed by atomic force microscopic (AFM) analysis. Results from Fourier-transform infrared spectroscopy (FT-IR), Bradford protein assay, and thermo-gravimetric analysis (TGA) indicated that PPL was covalently attached to the surface of magnetic nanoparticles with a PPL immobilization yield of 50 mg enzyme/g MNPs. Vibrating sample magnetometer (VSM) analysis revealed that the MNPs-PPL nanocomposite had a high saturation magnetization of 42.25 emu·g −1 . The properties of the immobilized PPL were investigated in comparison with the free enzyme counterpart. Enzymatic activity, reusability, thermo-stability, and storage stability of the immobilized PPL were found significantly superior to those of the free one. The K m and the V max values (0.02 mM, 6.40 U·mg −1 enzyme) indicated the enhanced activity of the immobilized PPL compared to those of the free enzyme (0.29 mM, 3.16 U·mg −1 enzyme). Furthermore, at an elevated temperature of 70 °C, immobilized PPL retained 60% of its initial activity. The PPL-MNPs nanocomposite was applied in the enzyme inhibition assays using orlistat, and two natural products isolated from oolong tea (i.e., EGCG and EGC) as the test compounds. - Highlights: • Porcine pancreatic lipase was firstly covalently immobilized onto carboxylated MNPs. • Immobilized porcine pancreatic lipase (PPL) was characterized by various techniques. • MNPs-PPL showed higher activity, reusability, and thermo-stability than

  1. Covalent immobilization of porcine pancreatic lipase on carboxyl-activated magnetic nanoparticles: Characterization and application for enzymatic inhibition assays

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Yuan-Ting [Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Ren, Xiao-Yun [Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041 (China); Liu, Yi-Ming [Department of Chemistry and Biochemistry, Jackson State University, 1400 Lynch St., Jackson, MS 39217 (United States); Wei, Ying [Changzhi Medical College, Changzhi 046000 (China); Qing, Lin-Sen [Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041 (China); Liao, Xun, E-mail: liaoxun@cib.ac.cn [Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041 (China)

    2014-05-01

    Using carboxyl functionalized silica-coated magnetic nanoparticles (MNPs) as carrier, a novel immobilized porcine pancreatic lipase (PPL) was prepared through the 1-ethyl-3-[3-dimethylaminopropyl] carbodiimide hydrochloride/N-hydroxysuccinimide (EDC/NHS) coupling reaction. Transmission electron microscopic images showed that the synthesized nanoparticles (Fe{sub 3}O{sub 4}–SiO{sub 2}) possessed three dimensional core–shell structures with an average diameter of ∼ 20 nm. The effective enzyme immobilization onto the nanocomposite was confirmed by atomic force microscopic (AFM) analysis. Results from Fourier-transform infrared spectroscopy (FT-IR), Bradford protein assay, and thermo-gravimetric analysis (TGA) indicated that PPL was covalently attached to the surface of magnetic nanoparticles with a PPL immobilization yield of 50 mg enzyme/g MNPs. Vibrating sample magnetometer (VSM) analysis revealed that the MNPs-PPL nanocomposite had a high saturation magnetization of 42.25 emu·g{sup −1}. The properties of the immobilized PPL were investigated in comparison with the free enzyme counterpart. Enzymatic activity, reusability, thermo-stability, and storage stability of the immobilized PPL were found significantly superior to those of the free one. The K{sub m} and the V{sub max} values (0.02 mM, 6.40 U·mg{sup −1} enzyme) indicated the enhanced activity of the immobilized PPL compared to those of the free enzyme (0.29 mM, 3.16 U·mg{sup −1} enzyme). Furthermore, at an elevated temperature of 70 °C, immobilized PPL retained 60% of its initial activity. The PPL-MNPs nanocomposite was applied in the enzyme inhibition assays using orlistat, and two natural products isolated from oolong tea (i.e., EGCG and EGC) as the test compounds. - Highlights: • Porcine pancreatic lipase was firstly covalently immobilized onto carboxylated MNPs. • Immobilized porcine pancreatic lipase (PPL) was characterized by various techniques. • MNPs-PPL showed higher activity

  2. Pyridoxine Supplementation Improves the Activity of Recombinant Glutamate Decarboxylase and the Enzymatic Production of Gama-Aminobutyric Acid.

    Directory of Open Access Journals (Sweden)

    Yan Huang

    Full Text Available Glutamate decarboxylase (GAD catalyzes the irreversible decarboxylation of L-glutamate to the valuable food supplement γ-aminobutyric acid (GABA. In this study, GAD from Escherichia coli K12, a pyridoxal phosphate (PLP-dependent enzyme, was overexpressed in E. coli. The GAD produced in media supplemented with 0.05 mM soluble vitamin B6 analog pyridoxine hydrochloride (GAD-V activity was 154.8 U mL-1, 1.8-fold higher than that of GAD obtained without supplementation (GAD-C. Purified GAD-V exhibited increased activity (193.4 U mg-1, 1.5-fold higher than that of GAD-C, superior thermostability (2.8-fold greater than that of GAD-C, and higher kcat/Km (1.6-fold higher than that of GAD-C. Under optimal conditions in reactions mixtures lacking added PLP, crude GAD-V converted 500 g L-1 monosodium glutamate (MSG to GABA with a yield of 100%, and 750 g L-1 MSG with a yield of 88.7%. These results establish the utility of pyridoxine supplementation and lay the foundation for large-scale enzymatic production of GABA.

  3. Enzymatic lipid oxidation by eosinophils propagates coagulation, hemostasis, and thrombotic disease

    Science.gov (United States)

    Uderhardt, Stefan; Ackermann, Jochen A.; Fillep, Tobias; Hammond, Victoria J.; Willeit, Johann; Stark, Konstantin; Rossaint, Jan; Schubert, Irene; Mielenz, Dirk; Dietel, Barbara; Raaz-Schrauder, Dorette; Ay, Cihan; Thaler, Johannes; Heim, Christian; Collins, Peter W.; Schabbauer, Gernot; Mackman, Nigel; Voehringer, David; Nadler, Jerry L.; Lee, James J.; Massberg, Steffen; Rauh, Manfred; O’Donnell, Valerie B.

    2017-01-01

    Blood coagulation is essential for physiological hemostasis but simultaneously contributes to thrombotic disease. However, molecular and cellular events controlling initiation and propagation of coagulation are still incompletely understood. In this study, we demonstrate an unexpected role of eosinophils during plasmatic coagulation, hemostasis, and thrombosis. Using a large-scale epidemiological approach, we identified eosinophil cationic protein as an independent and predictive risk factor for thrombotic events in humans. Concurrent experiments showed that eosinophils contributed to intravascular thrombosis by exhibiting a strong endogenous thrombin-generation capacity that relied on the enzymatic generation and active provision of a procoagulant phospholipid surface enriched in 12/15-lipoxygenase–derived hydroxyeicosatetraenoic acid–phosphatidylethanolamines. Our findings reveal a previously unrecognized role of eosinophils and enzymatic lipid oxidation as regulatory elements that facilitate both hemostasis and thrombosis in response to vascular injury, thus identifying promising new targets for the treatment of thrombotic disease. PMID:28566277

  4. Increased release of fermentable sugars from elephant grass by enzymatic hydrolysis in the presence of surfactants

    International Nuclear Information System (INIS)

    Menegol, Daiane; Scholl, Angélica Luisi; Fontana, Roselei Claudete; Dillon, Aldo José Pinheiro; Camassola, Marli

    2014-01-01

    Highlights: • Milling is an attractive method to enhance the enzymatic hydrolysis of biomass. • Surfactants improve the efficiency of lignocellulose enzymatic hydrolysis. • Pretreatment with NaOH, smaller particle size and Tween 80® were more efficient. - Abstract: In the search for renewable energy sources, elephant grass is an alternative substrate for ethanol production, but this substrate must be hydrolyzed by cellulases and xylanases to liberate fermentable sugars. During enzymatic hydrolysis, cellulase activity is reduced by the irreversible adsorption of cellulase onto cellulose, decreasing the rate of hydrolysis. Adding surfactants during hydrolysis can improve the process. The effects of Tween® and Triton® surfactants on the enzymatic hydrolysis of elephant grass were evaluated in this context. The data indicate that pretreatment with sodium hydroxide, along with a smaller particle size (0.075–0.152 mm) and the use of Tween 80®, increased the efficiency of releasing reducing sugars from pretreated elephant grass biomass. Thus, it is possible to reduce grinding costs in second-generation ethanol production through the use of surfactants, as they allow efficient hydrolysis of larger biomass particles

  5. Effects of Enzymatically Synthesized Glycogen and Exercise on Abdominal Fat Accumulation in High-Fat Diet-Fed Mice.

    Science.gov (United States)

    Tamura, Shohei; Honda, Kazuhisa; Morinaga, Ryoji; Saneyasu, Takaoki; Kamisoyama, Hiroshi

    2017-01-01

    The combination of diet and exercise is the first choice for the treatment of obesity and metabolic syndrome. We previously reported that enzymatically synthesized glycogen (ESG) suppresses abdominal fat accumulation in obese rats. However, the effect of the combination of ESG and exercise on abdominal fat accumulation has not yet been investigated. Our goal in this study was therefore to evaluate the effects of dietary ESG and its combination with exercise on abdominal fat accumulation in high-fat diet (HFD)-fed mice. Male ICR mice were assigned to four groups: HFD, HFD containing 20% ESG, HFD with exercise, HFD containing 20% ESG with exercise. Treadmill exercise was performed for 3 wk (25 m/min, 30 min/d, 3 d/wk) after 5-d adaption to running at that speed. Both ESG and exercise significantly reduced the weights of abdominal adipose tissues. In addition, the combination of ESG and exercise significantly suppressed abdominal fat accumulation, suggesting that ESG and exercise showed an additive effect. Exercise significantly increased the mRNA levels of lipid metabolism-related genes such as lipoprotein lipase, peroxisome proliferator-activated receptor delta; factor-delta (PPARδ), carnitin palmitoyltransferase b, adipose triglyceride lipase (ATGL), and uncoupling protein-3 in the gastrocnemius muscle. On the other hand, dietary ESG significantly decreased the mRNA levels of PPARδ and ATGL in the gastrocnemius muscle. These results suggest that the combined treatment of ESG and exercise effectively suppresses abdominal fat accumulation in HFD-fed mice by different mechanisms.

  6. Effect of micro-stirring on enzymatic reaction kinetics inside a biomimetic container

    Science.gov (United States)

    Gozen, Irep; Horowitz, Viva; Chambers, Zachary; Manoharan, Vinothan

    The intracellular environment is dynamic, influenced by the motion of active machinery such as cytoskeleton filaments and molecular motors. To understand whether and how such activity affects the rates of diffusion-limited reactions, we construct a model system consisting of a phospholipid vesicle encapsulating a small number of micro- or nanoparticles, the active motion of which can be induced by chemical or magnetic cues. We aim to determine a relation between active motion of particles and rates of enzymatic reactions in the confined volume. Our findings might illuminate how active motion influences cytoplasmic reaction dynamics, or may have played a role in protocell genetics.

  7. The synthesis of amphipathic prodrugs of 1,2-diol drugs with saccharide conjugates by high regioselective enzymatic protocol.

    Science.gov (United States)

    Quan, Jing; Chen, Zhichun; Han, Chengyou; Lin, Xianfu

    2007-02-15

    A facile, high regioselective enzymatic synthesis approach for the preparation of amphipathic prodrugs with saccharides of mephenesin and chlorphenesin was developed. Firstly, transesterification of two drugs with divinyl dicarboxylates with different carbon chain length was performed under the catalysis of Candida antarctica lipase acrylic resin and Lipozyme in anhydrous acetone at 50 degrees C, respectively. A series of lipophilic derivatives with vinyl groups of mephenesin and chlorphenesin were prepared. The influences of different organic solvents, enzyme sources, reaction time, and the acylation reagents on the synthesis of vinyl esters were investigated. And then, protease-catalyzed high regioselective acylation of D-glucose and D-mannose with vinyl esters of mephenesin and chlorphenesin gave drug-saccharide derivatives in good yields. The studies of lipophilicity and hydrolysis in vitro of prodrugs verified that drug-saccharide derivatives had amphipathic properties, and both lipophilic and amphipathic drug derivatives had obvious controlled release characteristics.

  8. Enhanced enzymatic hydrolysis and acetone-butanol-ethanol fermentation of sugarcane bagasse by combined diluted acid with oxidate ammonolysis pretreatment.

    Science.gov (United States)

    Li, Hailong; Xiong, Lian; Chen, Xuefang; Wang, Can; Qi, Gaoxiang; Huang, Chao; Luo, Mutan; Chen, Xinde

    2017-03-01

    This study aims to propose a biorefinery pretreatment technology for the bioconversion of sugarcane bagasse (SB) into biofuels and N-fertilizers. Performance of diluted acid (DA), aqueous ammonia (AA), oxidate ammonolysis (OA) and the combined DA with AA or OA were compared in SB pretreatment by enzymatic hydrolysis, structural characterization and acetone-butanol-ethanol (ABE) fermentation. Results indicated that DA-OA pretreatment improves the digestibility of SB by sufficiently hydrolyzing hemicellulose into fermentable monosaccharides and oxidating lignin into soluble N-fertilizer with high nitrogen content (11.25%) and low C/N ratio (3.39). The enzymatic hydrolysates from DA-OA pretreated SB mainly composed of glucose was more suitable for the production of ABE solvents than the enzymatic hydrolysates from OA pretreated SB containing high ratio of xylose. The fermentation of enzymatic hydrolysates from DA-OA pretreated SB produced 12.12g/L ABE in 120h. These results suggested that SB could be utilized efficient, economic, and environmental by DA-OA pretreatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Enzymatic preparation and characterization of soybean lecithin-based emulsifiers

    OpenAIRE

    R. C. Reddy Jala; B. Chen; H. Li; Y. Zhang; L-Z Cheong; T. Yang; X. Xu

    2016-01-01

    Simple enzymatic methods were developed for the synthesis of lysolecithin, glycerolyzed lecithin and hydrolyzed lecithin. The products were characterized in terms of their acetone insoluble matter, hexane insoluble matter, moisture, phospholipid distribution and fatty acid composition. The HLB value ranges of different products with different acid values were detected. The efficiency of optimally hydrolyzed lecithin was examined at high calcium ion, low pH, and aqueous solutions and compared ...

  10. Fabrication of Nickel/nanodiamond/boron-doped diamond electrode for non-enzymatic glucose biosensor

    International Nuclear Information System (INIS)

    Dai, Wei; Li, Mingji; Gao, Sumei; Li, Hongji; Li, Cuiping; Xu, Sheng; Wu, Xiaoguo; Yang, Baohe

    2016-01-01

    Highlights: • Nanodiamonds (NDs) were electrophoretically deposited on the BDD film. • The NDs significantly extended the potential window. • Ni/NDs/BDD electrode was prepared by electrodeposition. • The electrode shows good catalytic activity for glucose oxidation. - Abstract: A stable and sensitive non-enzymatic glucose sensor was prepared by modifying a boron-doped diamond (BDD) electrode with nickel (Ni) nanosheets and nanodiamonds (NDs). The NDs were electrophoretically deposited on the BDD surface, and acted as nucleation sites for the subsequent electrodeposition of Ni. The morphology and composition of the modified BDD electrodes were characterized by field-emission scanning electron microscopy and energy-dispersive X-ray spectroscopy, respectively. The Ni nanosheet-ND modified BDD electrode exhibited good current response towards the non-enzymatic oxidation of glucose in alkaline media. The NDs significantly extended the potential window. The response to glucose was linear over the 0.2–1055.4-μM range. The limit of detection was 0.05 μM, at a signal-to-noise ratio of 3. The Ni nanosheet-ND/BDD electrode exhibited good selectivity, reproducibility and stability. Its electrochemical performance, low cost and simple preparation make it a promising non-enzymatic glucose sensor.

  11. Unravelling the importance of forest age stand and forest structure driving microbiological soil properties, enzymatic activities and soil nutrients content in Mediterranean Spanish black pine(Pinus nigra Ar. ssp. salzmannii) Forest.

    Science.gov (United States)

    Lucas-Borja, M E; Hedo, J; Cerdá, A; Candel-Pérez, D; Viñegla, B

    2016-08-15

    This study aimed to investigate the effects that stand age and forest structure have on microbiological soil properties, enzymatic activities and nutrient content. Thirty forest compartments were randomly selected at the Palancares y Agregados managed forest area (Spain), supporting forest stands of five ages; from 100 to 80years old to compartments with trees that were 19-1years old. Forest area ranging from 80 to 120years old and without forest intervention was selected as the control. We measured different soil enzymatic activities, soil respiration and nutrient content (P, K, Na, Mg, Cr, Mn, Fe, Co, Ni, Cu, Zn, Pb and Ca) in the top cm of 10 mineral soils in each compartment. Results showed that the lowest forest stand age and the forest structure created by management presented lower values of organic matter, soil moisture, water holding capacity and litterfall and higher values of C/N ratio in comparison with the highest forest stand age and the related forest structure, which generated differences in soil respiration and soil enzyme activities. The forest structure created by no forest management (control plot) presented the highest enzymatic activities, soil respiration, NH4(+) and NO3(-). Results did not show a clear trend in nutrient content comparing all the experimental areas. Finally, the multivariate PCA analysis clearly clustered three differentiated groups: Control plot; from 100 to 40years old and from 39 to 1year old. Our results suggest that the control plot has better soil quality and that extreme forest stand ages (100-80 and 19-1years old) and the associated forest structure generates differences in soil parameters but not in soil nutrient content. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Release of Antioxidant Capacity from Five Plant Foods during a Multistep Enzymatic Digestion Protocol

    NARCIS (Netherlands)

    Papillo, V.A.; Vitaglione, P.; Graziani, G.; Gokmen, V.; Fogliano, V.

    2014-01-01

    This study aimed at elucidating the influence of food matrix on the release of antioxidant activity from five plant foods (apple, spinach, walnut, red bean, and whole wheat). To this purpose a protocol based on sequential enzymatic digestion was adopted. The total antioxidant capacity (TAC) of both

  13. Optimization of fed-batch enzymatic hydrolysis from alkali-pretreated sugarcane bagasse for high-concentration sugar production.

    Science.gov (United States)

    Gao, Yueshu; Xu, Jingliang; Yuan, Zhenhong; Zhang, Yu; Liu, Yunyun; Liang, Cuiyi

    2014-09-01

    Fed-batch enzymatic hydrolysis process from alkali-pretreated sugarcane bagasse was investigated to increase solids loading, produce high-concentration fermentable sugar and finally to reduce the cost of the production process. The optimal initial solids loading, feeding time and quantities were examined. The hydrolysis system was initiated with 12% (w/v) solids loading in flasks, where 7% fresh solids were fed consecutively at 6h, 12h, 24h to get a final solids loading of 33%. All the requested cellulase loading (10 FPU/g substrate) was added completely at the beginning of hydrolysis reaction. After 120 h of hydrolysis, the maximal concentrations of cellobiose, glucose and xylose obtained were 9.376 g/L, 129.50 g/L, 56.03 g/L, respectively. The final total glucan conversion rate attained to 60% from this fed-batch process. Copyright © 2014. Published by Elsevier Ltd.

  14. Experimental primers containing synthetic and natural compounds reduce enzymatic activity at the dentin–adhesive interface under cyclic loading

    Science.gov (United States)

    Sousa, Ana Beatriz Silva; de Mattos Pimenta Vidal, Cristina; Leme-Kraus, Ariene Arcas; de Carvalho Panzeri Pires-de-Souza, Fernanda; Bedran-Russo, Ana K.

    2016-01-01

    Objective To evaluate the effect of experimental primers (chlorhexidine, enriched mixture of proanthocyanidins and doxycycline) on the adhesive properties and gelatinolytic activity at dentin-resin interfaces of occlusal Class I restorations. Methods The inactivation of enzymes by the experimental primers was assessed by fluorescence assay and gelatin zymography. To assess the adhesive properties, occlusal Class I cavities were prepared in sound human molars, etched with phosphoric acid and restored with one of the primers and an etch-and-rinse adhesive system (Adper Single Bond Plus - 3M ESPE). After the restorative procedures, the specimens were divided into two subgroups (n = 6) consisting of storage in incubation buffer or axial cyclic loading at 50 N and 1,000,000 cycles. Then, the sectioned and sliced specimens were assigned to in situ zymography assay and microtensile bond strength (TBS) test. Results Fluorescence assay and gelatin zymography revealed that the experimental primers inactivated rMMPs. In situ zymography (2-way ANOVA, Tukey, p 0.05). Significance The use of experimental primers impaired the enzymatic activity at the dentin-adhesive interface after cyclic loading and the activity of rMMPs. Cyclic loading did not have a significant effect on the bond strength. PMID:27524231

  15. EFFECT OF LIGNIN CONTENT ON ENZYMATIC HYDROLYSIS OF FURFURAL RESIDUES

    Directory of Open Access Journals (Sweden)

    Jianxin Jiang

    2011-02-01

    Full Text Available The enzymatic saccharification of pretreated furfural residues with different lignin content was studied to verify the effect of lignin removal in the hydrolysis process. The results showed that the glucose yield was improved by increasing the lignin removal. A maximum glucose yield of 96.8% was obtained when the residue with a lignin removal of 51.4% was hydrolyzed for 108 h at an enzyme loading of 25 FPU/g cellulose. However, further lignin removal did not increase the hydrolysis. The effect of enzyme loading on the enzymatic hydrolysis was also explored in this work. It was concluded that a high glucose yield of 90% was achieved when the enzyme dosage was reduced from 25 to 15 FPU/g cellulose, which was cost-effective for the sugar and ethanol production. The structures of raw material and delignified samples were further characterized by XRD and scanning electron microscopy (SEM.

  16. Phytase production by Rhizopus microsporus var. microsporus biofilm: characterization of enzymatic activity after spray drying in presence of carbohydrates and nonconventional adjuvants.

    Science.gov (United States)

    Sato, Vanessa Sayuri; Jorge, João Atílio; Oliveira, Wanderley Pereira; Souza, Claudia Regina Fernandez; Guimarães, Luis Henrique Souza

    2014-02-28

    Microbial phytases are enzymes with biotechnological interest for the feed industry. In this article, the effect of spray-drying conditions on the stability and activity of extracellular phytase produced by R. microsporus var. microsporus biofilm is described. The phytase was spray-dried in the presence of starch, corn meal (>150 μm), soy bean meal (SB), corn meal (drying adjuvants. The residual enzyme activity after drying ranged from 10.7% to 60.4%, with SB and CM standing out as stabilizing agents. Water concentration and residual enzyme activity were determined in obtained powders as a function of the drying condition. When exposed to different pH values, the SB and CM products were stable, with residual activity above 50% in the pH range from 4.5 to 8.5 for 60 min. The use of CM as drying adjuvant promoted the best retention of enzymatic activity compared with SB. Spray drying of the R. microsporus var. microsporus phytase using different drying adjuvants showed interesting results, being quite feasible with regards their biotechnological applications, especially for poultry diets.

  17. The Enzymatic Oxidation of Graphene Oxide

    Science.gov (United States)

    Kotchey, Gregg P.; Allen, Brett L.; Vedala, Harindra; Yanamala, Naveena; Kapralov, Alexander A.; Tyurina, Yulia Y.; Klein-Seetharaman, Judith; Kagan, Valerian E.; Star, Alexander

    2011-01-01

    Two-dimensional graphitic carbon is a new material with many emerging applications, and studying its chemical properties is an important goal. Here, we reported a new phenomenon – the enzymatic oxidation of a single layer of graphitic carbon by horseradish peroxidase (HRP). In the presence of low concentrations of hydrogen peroxide (~40 µM), HRP catalyzed the oxidation of graphene oxide, which resulted in the formation of holes on its basal plane. During the same period of analysis, HRP failed to oxidize chemically reduced graphene oxide (RGO). The enzymatic oxidation was characterized by Raman, UV-Vis, EPR and FT-IR spectroscopy, TEM, AFM, SDS-PAGE, and GC-MS. Computational docking studies indicated that HRP was preferentially bound to the basal plane rather than the edge for both graphene oxide and RGO. Due to the more dynamic nature of HRP on graphene oxide, the heme active site of HRP was in closer proximity to graphene oxide compared to RGO, thereby facilitating the oxidation of the basal plane of graphene oxide. We also studied the electronic properties of the reduced intermediate product, holey reduced graphene oxide (hRGO), using field-effect transistor (FET) measurements. While RGO exhibited a V-shaped transfer characteristic similar to a single layer of graphene that was attributed to its zero band gap, hRGO demonstrated a p-type semiconducting behavior with a positive shift in the Dirac points. This p-type behavior rendered hRGO, which can be conceptualized as interconnected graphene nanoribbons, as a potentially attractive material for FET sensors. PMID:21344859

  18. The mechanism of action of lymphokines. IX. The enzymatic basis of hydrogen peroxide production by lymphokine-activated macrophages.

    Science.gov (United States)

    Freund, M; Pick, E

    1986-08-15

    The purpose of this study was to elucidate the biochemical basis of the enhanced hydrogen peroxide (H2O2) production by guinea pig peritoneal macrophages (MP) cultured in lymphokine (LK)-containing medium. The markedly augmented H2O2 generation by these cells, demonstrable by the horseradish peroxidase (HRP)-catalyzed oxidation of phenol red, is distinguished by its lack of dependence on a second stimulus. We demonstrate that H2O2 production is truly spontaneous and is not caused by a stimulant present among the H2O2 assay reagents. The principal candidate for such a role was HRP type II (a mixture of five isoenzymes) that was reported to be capable of eliciting an oxidative burst in MP. Four distinct HRP isoenzymes that were found incapable of provoking an oxidative response were nevertheless adequate for demonstrating H2O2 production by LK-activated MP. Blocking the MP receptor for mannose by the addition of mannan to the assay system resulted in enhanced detection of H2O2 by low concentrations of HRP type II and by three out of four HRP isoenzymes. Treatment of MP with LK-containing medium for 72 hr did not result in a significant change in the activity of cellular superoxide dismutase (SOD) compared with MP cultured for the same length of time in control medium. By using the specific inhibitor of copper, zinc-containing SOD, sodium diethyldithiocarbamate (DDC), and the universal SOD inhibitor, sodium nitroprusside, we found that the predominant enzyme in guinea pig peritoneal MP is probably manganese-containing SOD. Incubation of LK-activated MP with nitroprusside resulted in almost total inhibition of H2O2 production and a simultaneous switch to superoxide (O2-) liberation. Similar exposure to DDC had no effect. These data indicate that H2O2 produced by LK-activated MP is derived exclusively by enzymatic dismutation of O2- mediated by a manganese-containing SOD. The increase in spontaneous H2O2 production induced by LK is therefore secondary to augmented O2

  19. Telomerase activation by genomic rearrangements in high-risk neuroblastoma

    Science.gov (United States)

    Peifer, Martin; Hertwig, Falk; Roels, Frederik; Dreidax, Daniel; Gartlgruber, Moritz; Menon, Roopika; Krämer, Andrea; Roncaioli, Justin L.; Sand, Frederik; Heuckmann, Johannes M.; Ikram, Fakhera; Schmidt, Rene; Ackermann, Sandra; Engesser, Anne; Kahlert, Yvonne; Vogel, Wenzel; Altmüller, Janine; Nürnberg, Peter; Thierry-Mieg, Jean; Thierry-Mieg, Danielle; Mariappan, Aruljothi; Heynck, Stefanie; Mariotti, Erika; Henrich, Kai-Oliver; Glöckner, Christian; Bosco, Graziella; Leuschner, Ivo; Schweiger, Michal R.; Savelyeva, Larissa; Watkins, Simon C.; Shao, Chunxuan; Bell, Emma; Höfer, Thomas; Achter, Viktor; Lang, Ulrich; Theissen, Jessica; Volland, Ruth; Saadati, Maral; Eggert, Angelika; de Wilde, Bram; Berthold, Frank; Peng, Zhiyu; Zhao, Chen; Shi, Leming; Ortmann, Monika; Büttner, Reinhard; Perner, Sven; Hero, Barbara; Schramm, Alexander; Schulte, Johannes H.; Herrmann, Carl; O’Sullivan, Roderick J.; Westermann, Frank; Thomas, Roman K.; Fischer, Matthias

    2016-01-01

    Neuroblastoma is a malignant paediatric tumour of the sympathetic nervous system1. Roughly half of these tumours regress spontaneously or are cured by limited therapy. By contrast, high-risk neuroblastomas have an unfavourable clinical course despite intensive multimodal treatment, and their molecular basis has remained largely elusive2–4. Here we have performed whole-genome sequencing of 56 neuroblastomas (high-risk, n = 39; low-risk, n = 17) and discovered recurrent genomic rearrangements affecting a chromosomal region at 5p15.33 proximal of the telomerase reverse transcriptase gene (TERT). These rearrangements occurred only in high-risk neuroblastomas (12/39, 31%) in a mutually exclusive fashion with MYCN amplifications and ATRX mutations, which are known genetic events in this tumour type1,2,5. In an extended case series (n = 217), TERT rearrangements defined a subgroup of high-risk tumours with particularly poor outcome. Despite a large structural diversity of these rearrangements, they all induced massive transcriptional upregulation of TERT. In the remaining high-risk tumours, TERT expression was also elevated in MYCN-amplified tumours, whereas alternative lengthening of telomeres was present in neuroblastomas without TERT or MYCN alterations, suggesting that telomere lengthening represents a central mechanism defining this subtype. The 5p15.33 rearrangements juxtapose the TERT coding sequence to strong enhancer elements, resulting in massive chromatin remodelling and DNA methylation of the affected region. Supporting a functional role of TERT, neuroblastoma cell lines bearing rearrangements or amplified MYCN exhibited both upregulated TERT expression and enzymatic telomerase activity. In summary, our findings show that remodelling of the genomic context abrogates transcriptional silencing of TERT in high-risk neuroblastoma and places telomerase activation in the centre of transformation in a large fraction of these tumours. PMID:26466568

  20. Enzymatic sulfation of tocopherols and tocopherol metabolites by human cytosolic sulfotransferases.

    Science.gov (United States)

    Hashiguchi, Takuyu; Kurogi, Katsuhisa; Sakakibara, Yoichi; Yamasaki, Masao; Nishiyama, Kazuo; Yasuda, Shin; Liu, Ming-Cheh; Suiko, Masahito

    2011-01-01

    Tocopherols are essential micronutrients for mammals widely known as potent lipid-soluble antioxidants that are present in cell membranes. Recent studies have demonstrated that most of the carboxychromanol (CEHC), a tocopherol metabolite, in the plasma exists primarily in sulfate- and glucuronide-conjugated forms. To gain insight into the enzymatic sulfation of tocopherols and their metabolites, a systematic investigation was performed using all 14 known human cytosolic sulfotransferases (SULTs). The results showed that the members of the SULT1 family displayed stronger sulfating activities toward tocopherols and their metabolites. These enzymes showed a substrate preference for γ-tocopherol over α-tocopherol and for γ-CEHC over other CEHCs. Using A549 human lung epithelial cells in a metabolic labeling study, a similar trend in the sulfation of tocopherols and CEHCs was observed. Collectively, the results obtained indicate that SULT-mediated enzymatic sulfation of tocopherols and their metabolites is a significant pathway for regulation of the homeostasis and physiological functions of these important compounds.

  1. Improvement on the concentrated grape juice physico-chemical characteristics by an enzymatic treatment and Membrane Separation Processes

    Directory of Open Access Journals (Sweden)

    PLÍNIO R.F. CAMPOS

    2016-03-01

    Full Text Available ABSTRACT In this work, the improvement on the concentrated grape juice physico-chemical characteristics by using an enzymatic treatment followed by Membrane Separation Process (MSP has been investigated. By using Novozym 33095(r and Ultrazym AFP L(r enzymes varying three operating parameters, the best result on the grape pulp characteristics was attained for the Novozym 33095(r performed at 35oC, 15 min. and 50 mgL-1. In micro/ultra filtration processes after enzymatic pretreatment, the best performance of the MSP with high permeate flux value and suitable grape juice characteristics was attained using 0.05 mm membrane pore size, 1 bar pressure and 40 oC treatment temperature. When reverse osmosis process is operated at 40 bar and 40oC, high soluble solid and low turbidity values are attained. An enzymatic treatment along with MSP has shown an alternative and efficient grape juice processing system, being possible to extend to other foods.

  2. Development of a heavy metals enzymatic-based assay using papain

    International Nuclear Information System (INIS)

    Shukor, Yunus; Baharom, Nor Azlan; Rahman, Fadhil Abd.; Abdullah, Mohd. Puad; Shamaan, Nor Aripin; Syed, Mohd. Arif

    2006-01-01

    A heavy metals enzymatic-based assay using papain was developed. Papain was assayed using the Casein-coomassie-dye-binding assay. The assay is sensitive to several heavy metals. The IC 50 (concentration of toxicant giving 50% inhibition) of Hg 2+ , Ag 2+ , Pb 2 , Zn 2+ is 0.39, 0.40, 2.16, 2.11 mg l -1 , respectively. For Cu 2+ and Cd 2+ the LOQ (limits of quantitation) is 0.004 and 0.1 mg l -1 , respectively. The IC 50 and LOQ values were found to be generally comparable to several other enzymatic and bioassays tests such as: immobilized urease, 15-min Microtox TM , 48 h Daphnia magna, and 96 h Rainbow trout. The papain assay is xenobiotics tolerant, has a wide pH for optimum activity, is temperature stable, and has a relatively quick assay time. The papain assay was used to identify polluted water samples from industrial sources in Penang, Malaysia. We found one site where the assay gave a positive toxic response. The toxicity of the site was confirmed using Atomic Emission Spectrometry analysis

  3. Temperature induced decoupling of enzymatic hydrolysis and carbon remineralization in long-term incubations of Arctic and temperate sediments

    DEFF Research Database (Denmark)

    Robador, Alberto; Brüchert, Volker; Steen, Andrew

    2010-01-01

    explored the temperature sensitivity of enzymatic hydrolysis and its connection to subsequent steps in anoxic organic carbon degradation in long-term incubations of sediments from the Arctic and the North Sea. These sediments were incubated under anaerobic conditions for 24 months at temperatures of 0, 10......, and 20 ºC. The short-term temperature response of the active microbial community was tested in temperature gradient block incubations. The temperature optimum of extracellular enzymatic hydrolysis, as measured with a polysaccharide (chondroitin sulfate), differed between Arctic and temperate habitats...

  4. Production of MAG via enzymatic glycerolysis

    Science.gov (United States)

    Jamlus, Norul Naziraa Ahmad; Derawi, Darfizzi; Salimon, Jumat

    2015-09-01

    Enzymatic glycerolysis of a medium chain methyl ester, methyl laurate was performed using lipase Candida antarctica (Novozyme 435) for 6 hours at 55°C. The percentage of components mixture of product were determined by using gas chromatography technique. The enzymatic reaction was successfully produced monolaurin (45.9 %), dilaurin (47.1 %) and trilaurin (7.0 %) respectively. Thin layer chromatography (TLC) plate also showed a good separation of component spots. Fourier transformation infra-red (FTIR) spectrum showed the presence of ester carbonyl at wavenumber 1739.99 cm-1 and hydrogen bonded O-H at 3512.03 cm-1. The product is potentially to be used as emulsifier and additive in food industry, pharmaceutical, as well as antibacterial.

  5. Longitudinal changes in PON1 enzymatic activities in Mexican-American mothers and children with different genotypes and haplotypes

    International Nuclear Information System (INIS)

    Huen, Karen; Harley, Kim; Bradman, Asa; Eskenazi, Brenda; Holland, Nina

    2010-01-01

    The paraoxonase 1 (PON1) enzyme prevents low-density lipoprotein oxidation and also detoxifies the oxon derivatives of certain neurotoxic organophosphate (OP) pesticides. PON1 activity in infants is low compared to adults, rendering them with lower metabolic and antioxidant capacities. We made a longitudinal comparison of the role of genetic variability on control of PON1 phenotypes in Mexican-American mothers and their children at the time of delivery (n = 388 and 338, respectively) and again 7 years later (n = 280 and 281, respectively) using generalized estimating equations models. At age 7, children's mean PON1 activities were still lower than those of mothers. This difference was larger in children with genotypes associated with low PON1 activities (PON1 -108TT , PON1 192QQ , and PON1 -909CC ). In mothers, PON1 activities were elevated at delivery and during pregnancy compared to 7 years later when they were not pregnant (p < 0.001). In non-pregnant mothers, PON1 polymorphisms and haplotypes accounted for almost 2-fold more variation of arylesterase (AREase) and chlorpyrifos-oxonase (CPOase) activity than in mothers at delivery. In both mothers and children, the five PON1 polymorphisms (192, 55, -108, -909, -162) explained a noticeably larger proportion of variance of paraoxonase activity (62-78%) than AREase activity (12.3-26.6%). Genetic control of PON1 enzymatic activity varies in children compared to adults and is also affected by pregnancy status. In addition to known PON1 polymorphisms, unidentified environmental, genetic, or epigenetic factors may also influence variability of PON1 expression and therefore susceptibility to OPs and oxidative stress.

  6. Lignosulfonate and elevated pH can enhance enzymatic saccharification of lignocelluloses

    Directory of Open Access Journals (Sweden)

    Wang ZJ

    2013-01-01

    Full Text Available Abstract Background Nonspecific (nonproductive binding (adsorption of cellulase by lignin has been identified as a key barrier to reduce cellulase loading for economical sugar and biofuel production from lignocellulosic biomass. Sulfite Pretreatment to Overcome Recalcitrance of Lignocelluloses (SPORL is a relatively new process, but demonstrated robust performance for sugar and biofuel production from woody biomass especially softwoods in terms of yields and energy efficiencies. This study demonstrated the role of lignin sulfonation in enhancing enzymatic saccharification of lignocelluloses – lignosulfonate from SPORL can improve enzymatic hydrolysis of lignocelluloses, contrary to the conventional belief that lignin inhibits enzymatic hydrolysis due to nonspecific binding of cellulase. Results The study found that lignosulfonate from SPORL pretreatment and from a commercial source inhibits enzymatic hydrolysis of pure cellulosic substrates at low concentrations due to nonspecific binding of cellulase. Surprisingly, the reduction in enzymatic saccharification efficiency of a lignocellulosic substrate was fully recovered as the concentrations of these two lignosulfonates increased. We hypothesize that lignosulfonate serves as a surfactant to enhance enzymatic hydrolysis at higher concentrations and that this enhancement offsets its inhibitive effect from nonspecific binding of cellulase, when lignosulfonate is applied to lignocellulosic solid substrates. Lignosulfonate can block nonspecific binding of cellulase by bound lignin on the solid substrates, in the same manner as a nonionic surfactant, to significantly enhance enzymatic saccharification. This enhancement is linearly proportional to the amount of lignosulfonate applied which is very important to practical applications. For a SPORL-pretreated lodgepole pine solid, 90% cellulose saccharification was achieved at cellulase loading of 13 FPU/g glucan with the application of its

  7. Dietary enzymatically treated Artemisia annua L. supplementation alleviates liver oxidative injury of broilers reared under high ambient temperature

    Science.gov (United States)

    Wan, Xiaoli; Zhang, Jingfei; He, Jintian; Bai, Kaiwen; Zhang, Lili; Wang, Tian

    2017-09-01

    Heat stress induced by high ambient temperature is a major concern in commercial broiler production. To evaluate the effects of dietary enzymatically treated Artemisia annua L. (EA) supplementation on growth performance and liver oxidative injury of broilers reared under heat stress, a total of 320 22-day-old male broilers were randomly allotted into five groups with eight replicates of eight birds each. Broilers in the control group were housed at 22 ± 1 °C and fed the basal diet. Broilers in the HS, HS-EA1, HS-EA2, and HS-EA3 groups were fed basal diet supplemented with 0, 0.75, 1.00, and 1.25 g/kg EA, respectively, and reared under cyclic high temperature (34 ± 1 °C for 8 h/day and 22 ± 1 °C for 16 h/day). Broilers fed EA diets had higher final body weight, average daily body weight gain, and average daily feed intake, as well as liver concentration of reduced glutathione, activities of antioxidant enzymes, abilities to inhibit hydroxyl radical and superoxide radical (HS-EA2 and HS-EA3), and lower liver concentrations of reactive oxygen metabolites, malondialdehyde, and protein carbonyl (HS-EA1, HS-EA2, and HS-EA3) than HS group ( P proteins 70 and 90, upregulated the mRNA levels of nuclear factor erythroid 2-related factor 2 (HS-EA1, HS-EA2, and HS-EA3) and heme oxygenase 1 (HS-EA2 and HS-EA3) in liver of heat-treated broilers ( P diet is 1.00-1.25 g/kg.

  8. Enzymatic transformation of nonfood biomass to starch

    Science.gov (United States)

    You, Chun; Chen, Hongge; Myung, Suwan; Sathitsuksanoh, Noppadon; Ma, Hui; Zhang, Xiao-Zhou; Li, Jianyong; Zhang, Y.-H. Percival

    2013-01-01

    The global demand for food could double in another 40 y owing to growth in the population and food consumption per capita. To meet the world’s future food and sustainability needs for biofuels and renewable materials, the production of starch-rich cereals and cellulose-rich bioenergy plants must grow substantially while minimizing agriculture’s environmental footprint and conserving biodiversity. Here we demonstrate one-pot enzymatic conversion of pretreated biomass to starch through a nonnatural synthetic enzymatic pathway composed of endoglucanase, cellobiohydrolyase, cellobiose phosphorylase, and alpha-glucan phosphorylase originating from bacterial, fungal, and plant sources. A special polypeptide cap in potato alpha-glucan phosphorylase was essential to push a partially hydrolyzed intermediate of cellulose forward to the synthesis of amylose. Up to 30% of the anhydroglucose units in cellulose were converted to starch; the remaining cellulose was hydrolyzed to glucose suitable for ethanol production by yeast in the same bioreactor. Next-generation biorefineries based on simultaneous enzymatic biotransformation and microbial fermentation could address the food, biofuels, and environment trilemma. PMID:23589840

  9. Radiation degradation and the subsequent enzymatic hydrolysis of waste paper

    International Nuclear Information System (INIS)

    Kamakura, M.; Kaetsu, I.

    1982-01-01

    Various studies have been carried out to find methods for the pretreatment of waste cellulosic materials to make them more susceptible to enzymatic hydrolysis. In the work reported here, the effects of preirradiating waste papers on subsequent enzymatic hydrolysis have been studied

  10. Enzymatic biomarkers can portray nanoCuO-induced oxidative and neuronal stress in freshwater shredders.

    Science.gov (United States)

    Pradhan, Arunava; Silva, Carla O; Silva, Carlos; Pascoal, Cláudia; Cássio, Fernanda

    2016-11-01

    Commercial applications of nanometal oxides have increased concern about their release into natural waters and consequent risks to aquatic biota and the processes they drive. In forest streams, the invertebrate shredder Allogamus ligonifer plays a key role in detritus food webs by transferring carbon and energy from plant litter to higher trophic levels. We assessed the response profiles of oxidative and neuronal stress enzymatic biomarkers in A. ligonifer after 96h exposure to nanoCuO at concentration ranges stress, Cu 2+ released from nanoCuO was quantified and the enzymatic responses to Cu 2+ exposure at similar effective concentrations were compared. The highest activities of superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione reductase (GR) were observed at concentrations stress at low concentrations (released ionic copper on enzyme activities were concentration-dependent, and led to oxidative stress and even to animal death. The activity of acetylcholinesterase (AChE) was strongly inhibited even at concentrations stress in A. ligonifer. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Immobilization of Lipase using Alginate Hydrogel Beads and Enzymatic Evaluation in Hydrolysis of p-Nitrophenol Butyrate

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Shuang; Shang, Wenting; Yang, Xiaoxi; Zhang, Shujuan; Zhang, Xiaogang; Chen, Jiawei [Renmin Univ. of China, Beijing (China)

    2013-09-15

    The immobilization of enzyme is one of the key issues both in the field of enzymatic research and industrialization. In this work, we reported a facile method to immobilize Candida Antarctica lipase B (CALB) in alginate carrier. In the presence of calcium cation, the enzyme-alginate suspension could be cross-linked to form beads with porous structure at room temperature, and the enzyme CALB was dispersed in the beads. Activity of the enzyme-alginate composite was verified by enzymatic hydrolysis reaction of p-nitrophenol butyrate in aqueous phase. The effects of reaction parameters such as temperature, pH, embedding and lyophilized time on the reactive behavior were discussed. Reuse cycle experiments for the hydrolysis of p-nitrophenol butyrate demonstrated that activity of the enzyme-alginate composite was maintained without marked deactivation up to 6 repeated cycles.

  12. Hormonal enzymatic systems in normal and cancerous human breast: control, prognostic factors, and clinical applications.

    Science.gov (United States)

    Pasqualini, Jorge R; Chetrite, Gérard S

    2012-04-01

    The bioformation and transformation of estrogens and other hormones in the breast tissue as a result of the activity of the various enzymes involved attract particular attention for the role they play in the development and pathogenesis of hormone-dependent breast cancer. The enzymatic process concerns the aromatase, which transforms androgens into estrogens; the sulfatase, which hydrolyzes the biologically inactive sulfates to the active hormone; the 17β-hydroxysteroid dehydrogenases, which are involved in the interconversion estradiol/estrone or testosterone/androstenedione; hydroxylases, which transform estrogens into mitotic and antimitotic derivatives; and sulfotransferases and glucuronidases, which, respectively convert into the biologically inactive sulfates and glucuronides. These enzymatic activities are more intense in the carcinoma than in the normal tissue. Concerning aromatase, the application of antiaromatase agents has been largely developed in the treatment of breast cancer patients, with very positive results. Various studies have shown that the activity levels of these enzymes and their mRNA can be involved as interesting prognostic factors for breast cancer. In conclusion, the application of new antienzymatic molecules can open attractive perspectives in the treatment of hormone-dependent breast cancer.

  13. Cobamide-mediated enzymatic reductive dehalogenation via long-range electron transfer.

    Science.gov (United States)

    Kunze, Cindy; Bommer, Martin; Hagen, Wilfred R; Uksa, Marie; Dobbek, Holger; Schubert, Torsten; Diekert, Gabriele

    2017-07-03

    The capacity of metal-containing porphyrinoids to mediate reductive dehalogenation is implemented in cobamide-containing reductive dehalogenases (RDases), which serve as terminal reductases in organohalide-respiring microbes. RDases allow for the exploitation of halogenated compounds as electron acceptors. Their reaction mechanism is under debate. Here we report on substrate-enzyme interactions in a tetrachloroethene RDase (PceA) that also converts aryl halides. The shape of PceA's highly apolar active site directs binding of bromophenols at some distance from the cobalt and with the hydroxyl substituent towards the metal. A close cobalt-substrate interaction is not observed by electron paramagnetic resonance spectroscopy. Nonetheless, a halogen substituent para to the hydroxyl group is reductively eliminated and the path of the leaving halide is traced in the structure. Based on these findings, an enzymatic mechanism relying on a long-range electron transfer is concluded, which is without parallel in vitamin B 12 -dependent biochemistry and represents an effective mode of RDase catalysis.

  14. Effect of high and low roughage total mixed ration diets on rumen metabolites and enzymatic profiles in crossbred cattle and buffaloes

    Directory of Open Access Journals (Sweden)

    S. K. Sinha

    2017-06-01

    Full Text Available Aim: A comparative study was conducted on crossbred cattle and buffaloes to investigate the effect of feeding high and low roughage total mixed ration (TMR diets on rumen metabolites and enzymatic profiles. Materials and Methods: Three rumen-fistulated crossbred cattle and buffalo were randomly assigned as per 3x3 switch over design for 21-days. Three TMR diets consisting of concentrate mixture, wheat straw and green maize fodder in the ratios of (T1 60:20:20, (T2 40:30:30, and (T3 20:40:40, respectively, were fed to the animals ad libitum. Rumen liquor samples were collected at 0, 2, 4, 6, and 8 h post feeding for the estimation of rumen biochemical parameters on 2 consecutive days in each trial. Results: The lactic acid concentration and pH value were comparable in both species and treatments. Feed intake (99.77±2.51 g/kg body weight, ruminal ammonia nitrogen, and total nitrogen were significantly (p0.05 among treatments and significantly (p<0.05 greater in crossbred cattle than buffaloes. Molar proportions of individual VFAs propionate (C3, propionate:butyrate (C3:C4, and (acetate+butyrate:propionate ([C2+C4]:C3 ratio in both crossbred cattle and buffalo were not affected by high or low roughage diet, but percentage of acetate and butyrate varied significantly (p<0.05 among treatment groups. Activities of microbial enzymes were comparable among species and different treatment groups. A total number of rumen protozoa were significantly (p<0.05 higher in crossbred cattle than buffaloes along with significantly (p<0.05 higher population in animal fed with high concentrate diet (T1. Conclusion: Rumen microbial population and fermentation depend on constituents of the treatment diet. However, microbial enzyme activity remains similar among species and different treatments. High concentrate diet increases number of rumen protozoa, and the number is higher in crossbred cattle than buffaloes.

  15. Effect of irradiation on enzymatic digestion of cellulosic wastes

    International Nuclear Information System (INIS)

    Chowdhury, N.A.; Matsuhashi, Shinpei; Hashimoto, Shoji; Kume, Tamikazu.

    1993-03-01

    Combination treatments with irradiation and other methods were examined to enhance the digestion of cellulosic materials such as sugar cane bagasse and rice straw. The amount of crude fiber (CF), acid detergent fiber (ADF) and neutral detergent fiber (NDF) of bagasse and rice straw were changed with various treatments. Alkali treatment (0.2N NaOH) was the most efficient for the enzymatic hydrolysis of bagasse and rice straw. Combination treatments with radiation and alkali or other methods increased their efficiency, and synergistic effect of radiation and alkali treatment was observed. Enzymatic digestion of CF of bagasse and rice straw treated by degassed water yielded high reducing sugar comparable to that of CF treated by alkali. CF of bagasse and rice straw treated by ozone did not show the significant increase in the release of reducing sugar upon saccharification. ADF and acid detergent lignin (ADL) contents decreased with the fermentation of bagasse by Coriolus versicolor. Electron microscopic observations also revealed the degradation of lignocellulosic components of bagasse. (author)

  16. Eschar removal by bromelain based enzymatic debridement (Nexobrid®) in burns: An European consensus.

    Science.gov (United States)

    Hirche, Christoph; Citterio, Antonella; Hoeksema, Henk; Koller, Ján; Lehner, Martina; Martinez, José Ramón; Monstrey, Stan; Murray, Alexandra; Plock, Jan A; Sander, Frank; Schulz, Alexandra; Ziegler, Benjamin; Kneser, Ulrich

    2017-12-01

    degree of consensus was remarkably high, with a unanimous consensus in 88.2% of statements, and lowest degree of consensus of 70% in only 3 statements. This consensus document may serve as preliminary guideline for the use of enzymatic debridement with user-oriented recommendations until further evidence and systematic guidelines are available. Copyright © 2017 Elsevier Ltd and ISBI. All rights reserved.

  17. Cloned Bacillus subtilis alkaline protease (aprA) gene showing high level of keratinolytic activity.

    Science.gov (United States)

    Zaghloul, T I

    1998-01-01

    The Bacillus subtilis alkaline protease(aprA) gene was previously cloned on a pUBHO-derivative plasmid. High levels of expression and gene stability were demonstrated when B. subtilis cells were grown on the laboratory medium 2XSG. B. subtilis cells harboring the multicopy aprA gene were grown on basal medium, supplemented with 1 % chicken feather as a source of energy, carbon, and nitrogen. Proteolytic and keratinolytic activities were monitored throughout the cultivation time. A high level of keratinolytic activity was obtained, and this indicates that alkaline protease is acting as a keratinase. Furthermore, considerable amounts of soluble proteins and free amino acids were obtained as a result of the enzymatic hydrolysis of feather. Biodegradation of feather waste using these cells represents an alternative way to improve the nutritional value of feather, since feather waste is currently utilized on a limited basis as a dietary protein supplement for animal feedstuffs. Moreover, the release of free amino acids from feather and the secreted keratinase enzyme would promote industries based on feather waste.

  18. A CuNi/C Nanosheet Array Based on a Metal-Organic Framework Derivate as a Supersensitive Non-Enzymatic Glucose Sensor

    Science.gov (United States)

    Zhang, Li; Ye, Chen; Li, Xu; Ding, Yaru; Liang, Hongbo; Zhao, Guangyu; Wang, Yan

    2018-06-01

    Bimetal catalysts are good alternatives for non-enzymatic glucose sensors owing to their low cost, high activity, good conductivity, and ease of fabrication. In the present study, a self-supported CuNi/C electrode prepared by electrodepositing Cu nanoparticles on a Ni-based metal-organic framework (MOF) derivate was used as a non-enzymatic glucose sensor. The porous construction and carbon scaffold inherited from the Ni-MOF guarantee good kinetics of the electrode process in electrochemical glucose detection. Furthermore, Cu nanoparticles disturb the array structure of MOF derived films and evidently enhance their electrochemical performances in glucose detection. Electrochemical measurements indicate that the CuNi/C electrode possesses a high sensitivity of 17.12 mA mM-1 cm-2, a low detection limit of 66.67 nM, and a wider linearity range from 0.20 to 2.72 mM. Additionally, the electrode exhibits good reusability, reproducibility, and stability, thereby catering to the practical use of glucose sensors. Similar values of glucose concentrations in human blood serum samples are detected with our electrode and with the method involving glucose-6-phosphate dehydrogenase; the results further demonstrate the practical feasibility of our electrode.

  19. Comparison of sodium carbonate pretreatment for enzymatic hydrolysis of wheat straw stem and leaf to produce fermentable sugars.

    Science.gov (United States)

    Jin, Yongcan; Huang, Ting; Geng, Wenhui; Yang, Linfeng

    2013-06-01

    The specific characteristics of biomass structure and chemical composition of straw stem and leaf may result in different behavior of pretreatment and enzymatic hydrolysis. In this work, sodium carbonate (SC) was employed as a pretreatment to improve the enzymatic digestibility of wheat straw. The chemical composition and enzymatic hydrolysis of wheat straw stem and leaf (sheath included) were investigated comparatively. Most of the polysaccharides are kept in the solid fractions after SC pretreatment, while the stem has better delignification selectivity than leaf at high temperature. The enzymatic hydrolysis efficiency of wheat straw leaf is significantly higher than that of stem. The maximum total sugar yield from SC pretreated leaf was about 16% higher than stem. The results show that sodium carbonate is of great potential to be used as a pretreatment for the production of bioethanol from straw handling waste in a straw pulp mill with a low feedstock cost. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Enzymatic Systems for Cellulose Acetate Degradation

    Directory of Open Access Journals (Sweden)

    Oskar Haske-Cornelius

    2017-09-01

    Full Text Available Cellulose acetate (CA-based materials, like cigarette filters, contribute to landscape pollution challenging municipal authorities and manufacturers. This study investigates the potential of enzymes to degrade CA and to be potentially incorporated into the respective materials, enhancing biodegradation. Deacetylation studies based on Liquid Chromatography-Mass Spectrometry-Time of Flight (LC-MS-TOF, High Performance Liquid Chromatography (HPLC, and spectrophotometric analysis showed that the tested esterases were able to deacetylate the plasticizer triacetin (glycerol triacetate and glucose pentaacetate (cellulose acetate model compound. The most effective esterases for deacetylation belong to the enzyme family 2 (AXE55, AXE 53, GAE, they deacetylated CA with a degree of acetylation of up to 1.8. A combination of esterases and cellulases showed synergistic effects, the absolute glucose recovery for CA 1.8 was increased from 15% to 28% when an enzymatic deacetylation was performed. Lytic polysaccharide monooxygenase (LPMO, and cellobiohydrolase were able to cleave cellulose acetates with a degree of acetylation of up to 1.4, whereas chitinase showed no activity. In general, the degree of substitution, chain length, and acetyl group distribution were found to affect CA degradation. This study shows that, for a successful enzyme-based deacetylation system, a cocktail of enzymes, which will randomly cleave and generate shorter CA fragments, is the most suitable.

  1. Oral administration of Saccharomyces boulardii alters duodenal morphology, enzymatic activity and cytokine production response in broiler chickens.

    Science.gov (United States)

    Sun, Yajing; Rajput, Imran Rashid; Arain, Muhammad Asif; Li, Yanfei; Baloch, Dost Muhammad

    2017-08-01

    The present study evaluated the effects of Saccharomyces boulardii on duodenal digestive enzymes, morphology and cytokine induction response in broiler chicken. A total of 200 birds were allotted into two groups (n = 100) and each group divided into five replications (n = 20). The control group was fed basal diet in addition to antibiotic (virginiamycin 20 mg/kg), and treatment group received (1 × 10 8  colony-forming units/kg feed) S. boulardii in addition to basal diet lasting for 72 days. The results compared to control group revealed that adenosine triphosphatase, gamma glutamyl transpeptidase, lipase and trypsin activities were higher, while, no significant improvement was observed in amylase activities in the duodenum of the treatment group. Moreover, morphological findings showed that villus height, width and number of goblet cells markedly increased. Additionally, transmission electron microscopy visualized that villus height, width and structural condensation significantly increased in the treatment group. The immunohistological observations showed increased numbers of immunoglobulin A (IgA)-positive cells in the duodenum of the treatment group. Meanwhile, cytokine production levels of tumor necrosis factor-α, interleukin (IL)-10, transforming growth factor-β and secretory IgA markedly increased, and IL-6 statistically remained unchanged as compared to the control group. These findings illustrated that initial contact of S. boulardii to the duodenum has significant impact in improving enzymatic activity, intestinal morphology and cytokine response in broiler chicken. © 2016 Japanese Society of Animal Science.

  2. High performance liquid chromatography method for the determination of cinnamyl alcohol dehydrogenase activity in soybean roots.

    Science.gov (United States)

    dos Santos, W D; Ferrarese, Maria de Lourdes Lucio; Ferrarese-Filho, O

    2006-01-01

    This study proposes a simple, quick and reliable method for determining the cinnamyl alcohol dehydrogenase (CAD; EC 1.1.1.195) activity in soybean (Glycine max L. Merr.) roots using reversed-phase high performance liquid chromatography (RP-HPLC). The method includes a single extraction of the tissue and conduction of the enzymatic reaction at 30 degrees C with cinnamaldehydes (coniferyl or sinapyl), substrates of CAD. Disappearance of the substrates in the reaction mixture is monitored at 340 nm (for coniferaldehyde) or 345 nm (for sinapaldehyde) by isocratic elution with methanol/acetic acid through a GLC-ODS (M) column. This HPLC technique furnishes a rapid and reliable measure of cinnamaldehyde substrates, and may be used as an alternative tool to analyze CAD activity in enzyme preparation without previous purification.

  3. The effects of fermentation and enzymatic treatment of pea on nutrient digestibility and growth performance of broilers.

    Science.gov (United States)

    Goodarzi Boroojeni, F; Senz, M; Kozłowski, K; Boros, D; Wisniewska, M; Rose, D; Männer, K; Zentek, J

    2017-10-01

    The present study examined the impacts of native, fermented or enzymatically treated peas (Pisum sativum L.) inclusion in broiler diets, on growth performance and nutrient digestibility. For the fermentation process, Madonna pea was mixed with water (1/1) containing 2.57×108 Bacillus subtilis (GalliPro®) spores/kg pea and then, incubated for 48 h at 30 °C. For the enzymatic treatment process, the used water for dough production contained three enzymes, AlphaGalTM (α-galactosidase), RONOZYME® ProAct and VP (protease and pectinases respectively - DSM, Switzerland) and the pea dough incubated for 24 h at 30°C. Nine corn-wheat-soybean diets were formulated by supplying 10%, 20% and 30% of the required CP with either native, fermented or enzymatically treated peas. Performance was recorded weekly and at the end of the experiment (day 35), apparent ileal digestibility (AID) of CP, amino acids (AA), crude fat, starch, Ca, P and K were determined. Data were subjected to ANOVA using GLM procedure with a 3×3 factorial arrangement of treatments. Both processes reduced α-galactosides, phytate, trypsin inhibitor activity and resistant starch in peas. Increasing levels of pea products up to 300 g/kg diet, reduced BW gain and feed intake (P⩽0.05). Broilers fed diets containing enzymatically treated pea had the best feed conversion ratio at day 35. Different types of pea product and their inclusion levels had no effect on AID of all nutrients. The interaction between type of the pea products and inclusion levels was significant for AID of starch. For native pea diets, 10% group showed similar AID of starch to 20% native pea but it had higher AID than 30% native pea. For fermented and enzymatically treated groups, all three levels displayed similar AID of starch. In conclusion, enzymatic treatment and fermentation could improve the nutritional quality of pea. Inclusion of enzymatically treated pea in broiler diets could improve broiler performance compared with other pea

  4. Influence of In vitro Digestion on Antioxidative Activity of Coconut ...

    African Journals Online (AJOL)

    Conclusion: CMPHs are high value-added antioxidants and possess a potential ..... side chain groups were expected to be exposed, ..... enzymatic digestion on antioxidant activity of coffee ... yam bean seed (Sphenostylis stenocarpa) protein.

  5. Human Papillomavirus 16 (HPV-16), HPV-18, and HPV-31 E6 Override the Normal Phosphoregulation of E6AP Enzymatic Activity.

    Science.gov (United States)

    Thatte, Jayashree; Banks, Lawrence

    2017-11-15

    The human papillomavirus (HPV) E6 oncoproteins recruit the cellular ubiquitin ligase E6AP/UBE3A to target cellular substrates for proteasome-mediated degradation, and one consequence of this activity is the E6 stimulation of E6AP autoubiquitination and degradation. Recent studies identified an autism-linked mutation within E6AP at T485, which was identified as a protein kinase A phosphoacceptor site and which could directly regulate E6AP ubiquitin ligase activity. In this study, we have analyzed how T485-mediated regulation of E6AP might affect E6 targeting of some of its known substrates. We show that modulation of T485 has no effect on the ability of E6 to direct either p53 or Dlg for degradation. Furthermore, T485 regulation has no effect on HPV-16 or HPV-31 E6-induced autodegradation of E6AP but does affect HPV-18 E6-induced autodegradation of E6AP. In cells derived from cervical cancers, we find low levels of both phosphorylated and nonphosphorylated E6AP in the nucleus. However, ablation of E6 results in a dramatic accumulation of phospho-E6AP in the cytoplasm, whereas nonphosphorylated E6AP accumulates primarily in the nucleus. Interestingly, E6AP phosphorylation at T485 confers association with 14-3-3 proteins, and this interaction seems to be important, in part, for the ability of E6 to recruit phospho-E6AP into the nucleus. These results demonstrate that HPV E6 overrides the normal phosphoregulation of E6AP, both in terms of its enzymatic activity and its subcellular distribution. IMPORTANCE Recent reports demonstrate the importance of phosphoregulation of E6AP for its normal enzymatic activity. Here, we show that HPV E6 is capable of overriding this regulation and can promote degradation of p53 and Dlg regardless of the phosphorylation status of E6AP. Furthermore, E6 interaction with E6AP also significantly alters how E6AP is subject to autodegradation and suggests that this is not a simple stimulation of an already-existing activity but rather a

  6. A Factorial Analysis Study on Enzymatic Hydrolysis of Fiber Pressed Oil Palm Frond for Bioethanol Production

    Science.gov (United States)

    Hashim, F. S.; Yussof, H. W.; Zahari, M. A. K. M.; Illias, R. M.; Rahman, R. A.

    2016-03-01

    Different technologies have been developed to for the conversion of lignocellulosic biomass to suitable fermentation substrates for bioethanol production. The enzymatic conversion of cellulose seems to be the most promising technology as it is highly specific and does not produce substantial amounts of unwanted byproducts. The effects of agitation speed, enzyme loading, temperature, pH and reaction time on the conversion of glucose from fiber pressed oil palm frond (FPOPF) for bioethanol production were screened by statistical analysis using response surface methodology (RSM). A half fraction two-level factorial analysis with five factors was selected for the experimental design to determine the best enzymatic conditions that produce maximum amount of glucose. FPOPF was pre-treated with alkaline prior to enzymatic hydrolysis. The enzymatic hydrolysis was performed using a commercial enzyme Cellic CTec2. From this study, the highest yield of glucose concentration was 9.736 g/L at 72 hours reaction time at 35 °C, pH 5.6, and 1.5% (w/v) of enzyme loading. The model obtained was significant with p-value model had a maximum point which is likely to be the optimum point and possible for the optimization process.

  7. Application of extended Kalman filter to identification of enzymatic deactivation.

    Science.gov (United States)

    Caminal, G; Lafuente, J; López-Santín, J; Poch, M; Solà, C

    1987-02-01

    A recursive estimation scheme, the Extended Kalman Filter (EKF) technique, was applied to study enzymatic deactivation in the enzymatic hydrolysis of pretreated cellulose using a model previously developed by the authors. When no deactivation model was assumed, the results showed no variation with time for all the model parameters except for the maximum rate of cellobiose-to-glucose conversion (r'(m)).The r'(m) variation occurred in two zones with a grace period. A new model of enzymatic hydrolysis of pretreated cellulose deactivation was proposed and validated showing better behavior than the old deactivation model. This approach allows one to study enzyme deactivation without additional experiments and within operational conditions.

  8. Structure of the enzymatically synthesized fructan inulin

    International Nuclear Information System (INIS)

    Heyer, A.G.; Schroeer, B.; Radosta, S.; Wolff, D.; Czapla, S.; Springer, J.

    1998-01-01

    Construction, purification and characterization of a fusion protein of maltose-binding protein of Escherichia coli and the fructosyltransferase of Streptococcus mutans is described. With the purified protein, in vitro synthesis of inulin was performed. The obtained polysaccharide was characterized by high-performance size-exclusion chromatography (HPSEC) and static light scattering (SLS) in dilute aqueous and dimethyl sulfoxide solution. For all samples very high molecular weights between 60x10 6 and 90x10 6 g/mol and a remarkable small polydispersity index of 1.1 have been determined. Small root-mean-square radii of gyration point to a compact conformation in dilute solution. No difference between native and enzymatically synthesized inulin was observed by X-ray powder diffraction and thermoanalysis of solid samples. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  9. Functional bio-based polyesters by enzymatic polymerization

    DEFF Research Database (Denmark)

    Daugaard, Anders Egede; Hoffmann, Christian; Andersen, Christian

    During recent years enzymatic polymerization has become increasingly popular as an alternative to classical polyesterification processes. The high regioselectivity observed for lipases permits preparation of novel polyesters with a high number of functional groups.1 This is particularly interesting...... polymerization was applied to prepare functional water soluble polyesters based on dimethyl itaconate and poly(ethyleneglycol).2 The monomer permits postfunctionalization using thiol-ene chemistry or aza-michael additions, which was used to illustrate the possibilites of preparing functional hydrogels. Hydrogels...... based on the polyesters were shown to be degradable and could be prepared either from the pure polyester or from prefunctionalized polyesters, though the thiol-ene reactions were found to be less effective. Since then a new monomer, trans-2,5-dihydroxy-3-pentenoic acid methyl ester (DPM) has been...

  10. The browning kinetics of the non-enzymatic browning reaction in L-ascorbic acid/basic amino acid systems

    Directory of Open Access Journals (Sweden)

    Ai-Nong YU

    Full Text Available Abstract Under the conditions of weak basis and the reaction temperature range of 110-150 °C, lysine, arginine and histidine were reacted with L-ascorbic acid at equal amount for 30-150 min, respectively and the formation of browning products was monitored with UV–vis spectrometry. The kinetic characteristics of their non-enzymatic browning reaction were investigated. The study results indicated that the non-enzymatic browning reaction of these three amino acids with L-ascorbic acid to form browning products was zero-order reaction. The apparent activation energies for the formation of browning products from L-ascorbic acid/lysine, L-ascorbic acid/arginine and L-ascorbic acid/histidine systems were 54.94, 50.08 and 35.31kJ/mol. The activation energy data indicated the degree of effects of reaction temperature on non-enzymatic browning reaction. Within the temperature range of 110-150 °C, the reaction rate of L-ascorbic acid/lysine system was the fastest one, followed by that of the L-ascorbic acid/arginine system. The reaction rate of L-ascorbic acid/histidine system was the slowest one. Based on the observed kinetic data, the formation mechanisms of browning products were proposed.

  11. Destructive effect of non-enzymatic glycation on catalase and remediation via curcumin.

    Science.gov (United States)

    Mofidi Najjar, Fayezeh; Taghavi, Fereshteh; Ghadari, Rahim; Sheibani, Nader; Moosavi-Movahedi, Ali Akbar

    2017-09-15

    Non-enzymatic glycation of proteins is a post-translational modification that is produced by a covalent binding between reducing sugars and amino groups of lysine and arginine residues. In this paper the effect of pathological conditions, derived from hyperglycemia on bovine liver catalase (BLC) as a model protein was considered by measuring enzyme activity, reactive oxygen species (ROS) generation, and changes in catalase conformational properties. We observed that in the presence of glucose, the catalase activity gradually decreased. ROS generation was also involved in the glycation process. Thus, decreased BLC activity was partly considered as a result of ROS generation through glycation. However, in the presence of curcumin the amount of ROS was reduced resulting in increased activity of the glycated catalase. The effect of high glucose level and the potential inhibitory effect of curcumin on aggregation and structural changes of catalase were also investigated. Molecular dynamic simulations also showed that interaction of catalase with curcumin resulted in changes in accessible surface area (ASA) and pKa, two effective parameters of glycation, in potential glycation lysine residues. Thus, the decrease in ASA and increase in pKa of important lysine residues were considered as predominant factors in decreased glycation of BLC by curcumin. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. High activity and low temperature optima of extracellular enzymes in Arctic sediments: implications for carbon cycling by heterotrophic microbial communities

    DEFF Research Database (Denmark)

    Arnosti, C.; Jørgensen, BB

    2003-01-01

    (chondroitin sulfate, fucoidan, xylan and pullulan) to determine the temperature-activity responses of hydrolysis of a related class of compounds. All 4 enzyme activities showed similarly low temperature optima in the range of 15 to 18degreesC. These temperature optima are considerably lower than most previous......The rate of the initial step in microbial remineralization of organic carbon, extracellular enzymatic hydrolysis, was investigated as a function of temperature in permanently cold sediments from 2 fjords on the west coast of Svalbard (Arctic Ocean). We used 4 structurally distinct polysaccharides...... reports of temperature optima for enzyme activities in marine sediments. At 0degreesC, close to the in situ temperature, these enzyme activities achieved 13 to 38% of their rates at optimum temperatures. In one experiment, sulfate reduction rates were measured in parallel with extracellular enzymatic...

  13. In vivo assay to identify bacteria with β-glucosidase activity

    Directory of Open Access Journals (Sweden)

    Erwin Strahsburger

    2017-11-01

    Conclusion: This in vivo β-glucosidase assay can be used as an enzymatic test on living cells without cell disruption. The method is simple, quantitative, and recommended, especially in studies screening for bacteria not only with β-glucosidase activity but also with high β-glucosidase activity.

  14. pH catalyzed pretreatment of corn bran for enhanced enzymatic arabinoxylan degradation

    DEFF Research Database (Denmark)

    Agger, Jane; Johansen, Katja Salomon; Meyer, Anne S.

    2011-01-01

    Corn bran is mainly made up of the pericarp of corn kernels and is a byproduct stream resulting from the wet milling step in corn starch processing. Through statistic modeling this study examined the optimization of pretreatment of corn bran for enzymatic hydrolysis. A low pH pretreatment (pH 2......, 150°C, 65min) boosted the enzymatic release of xylose and glucose and maximized biomass solubilization. With more acidic pretreatment followed by enzymatic hydrolysis the total xylose release was maximized (at pH 1.3) reaching ∼50% by weight of the original amount present in destarched corn bran......, but the enzyme catalyzed xylose release was maximal after pretreatment at approx. pH 2. The total glucose release peaked after pretreatment of approx. pH 1.5 with an enzymatic release of approx. 68% by weight of the original amounts present in destarched corn bran. For arabinose the enzymatic release...

  15. Enhancement of enzymatic saccharification of Eucalyptus globulus: steam explosion versus steam treatment.

    Science.gov (United States)

    Martin-Sampedro, Raquel; Revilla, Esteban; Villar, Juan C; Eugenio, Maria E

    2014-09-01

    Steam explosion and steam pre-treatment have proved capable of enhancing enzymatic saccharification of lignocellulosic materials. However, until now, these methods had not been compared under the same operational conditions and using the same raw material. Both pre-treatments lead to increased yields in the saccharification of Eucalyptus globulus; but results have been better with steam pre-treatments, despite the more accessible surface of exploded samples. The reason for this finding could be enzymatic inhibition: steam explosion causes a more extensive extraction of hemicelluloses and releases a greater amount of degradation products which can inhibit enzymatic action. Enzymatic inhibition is also dependent on the amount and chemical structure of lignin, which was also a contributing factor to the lower enzymatic yields obtained with the most severe pre-treatment. Thus, the highest yields (46.7% glucose and 73.4% xylose yields) were obtained after two cycle of steam treatment, of 5 and 3 min, at 183°C. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Enzymatic Synthesis of Biobased Polyesters and Polyamides

    Directory of Open Access Journals (Sweden)

    Yi Jiang

    2016-06-01

    Full Text Available Nowadays, “green” is a hot topic almost everywhere, from retailers to universities to industries; and achieving a green status has become a universal aim. However, polymers are commonly considered not to be “green”, being associated with massive energy consumption and severe pollution problems (for example, the “Plastic Soup” as a public stereotype. To achieve green polymers, three elements should be entailed: (1 green raw materials, catalysts and solvents; (2 eco-friendly synthesis processes; and (3 sustainable polymers with a low carbon footprint, for example, (biodegradable polymers or polymers which can be recycled or disposed with a gentle environmental impact. By utilizing biobased monomers in enzymatic polymerizations, many advantageous green aspects can be fulfilled. For example, biobased monomers and enzyme catalysts are renewable materials that are derived from biomass feedstocks; enzymatic polymerizations are clean and energy saving processes; and no toxic residuals contaminate the final products. Therefore, synthesis of renewable polymers via enzymatic polymerizations of biobased monomers provides an opportunity for achieving green polymers and a future sustainable polymer industry, which will eventually play an essential role for realizing and maintaining a biobased and sustainable society.

  17. Metal nanostructures for non-enzymatic glucose sensing

    International Nuclear Information System (INIS)

    Tee, Si Yin; Teng, Choon Peng; Ye, Enyi

    2017-01-01

    This review covers the recent development of metal nanostructures in electrochemical non-enzymatic glucose sensing. It highlights a variety of nanostructured materials including noble metals, other transition metals, bimetallic systems, and their hybrid with carbon-based nanomaterials. Particularly, attention is devoted to numerous approaches that have been implemented for improving the sensors performance by tailoring size, shape, composition, effective surface area, adsorption capability and electron-transfer properties. The correlation of the metal nanostructures to the glucose sensing performance is addressed with respect to the linear concentration range, sensitivity and detection limit. In overall, this review provides important clues from the recent scientific achievements of glucose sensor nanomaterials which will be essentially useful in designing better and more effective electrocatalysts for future electrochemical sensing industry. - Highlights: • Overview of recent development of metal nanostructures in electrochemical non-enzymatic glucose sensing. • Special attention is focussed on noble metals, other transition metals, bimetallic systems, and their hybrid with carbon-based nanomaterials. • Merits and limitations of various metal nanostructures in electrochemical non-enzymatic glucose sensing. • Strategies to improve the glucose sensing performance of metal nanostructures as electrocatalysts.

  18. Enzymatic oxidation of rutin by horseradish peroxidase: kinetic mechanism and identification of a dimeric product by LC-Orbitrap mass spectrometry.

    Science.gov (United States)

    Savic, Sasa; Vojinovic, Katarina; Milenkovic, Sanja; Smelcerovic, Andrija; Lamshoeft, Marc; Petronijevic, Zivomir

    2013-12-15

    Flavonoid oxidation is important issue in food processing and quality. The kinetic mechanism of enzymatic oxidation of rutin by horseradish peroxidase (HRP) was studied. Rutin oxidation reaction was followed by recording of spectral changes over the time at 360 nm. The studied oxidation is mostly enzymatic and less part non-enzymatic. The reaction with HRP has a higher rate compared with the reaction without of HRP, whereby is part of non-enzymatic reaction about 10% of the total reaction. Kinetic parameters were determined from graphics of linear Michaelis-Menten equation, and it was found that investigated reactions of rutin oxidation by HRP take place in a ping-pong kinetic mechanism. High resolution HPLC-MS analysis of the mixture of oxidized products of rutin revealed the presence of rutin dimer. Because of widely distribution of rutin as well as presence of peroxidases and hydrogen peroxide in fresh foods identification of this enzymatic modification product can be beneficial for foods quality and safety. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. Cellulase and xylanase activity during the decomposition of three aquatic macrophytes in a tropical oxbow lagoon

    Directory of Open Access Journals (Sweden)

    L Sciessere

    2011-09-01

    Full Text Available Due to the connection between enzymatic activity and degradation of different fractions of organic matter, enzyme assays can be used to estimate degradation rates of particulate and dissolved organic carbon in freshwater systems. The aim of this study was to quantify and model the enzymatic degradation involving the decomposition of macrophytes, describing temporal activity of cellulases (EC 3.2.1.4 and EC 3.2.1.91 and xylanase (EC 3.2.1.8 during in situ decomposition of three aquatic macrophytes (Salvinia sp., Eichhornia azurea and Cyperus giganteus on the surface and water-sediment interface (w-s interface of an oxbow lagoon (Óleo lagoon within a natural Brazilian Savanna Reserve. Overall, the enzymatic degradation of aquatic macrophytes in Óleo lagoon occurred during the whole year and was initiated together with leaching. Xylanase production was ca. 5 times higher than cellulase values due to easy access to this compound by cellulolytic microorganisms. Enzymatic production and detritus mass decay were similar on the surface and w-s interface. Salvinia sp. was the most recalcitrant detritus, with low mass decay and enzymatic activity. E. azurea and C. giganteus decomposition rates and enzymatic production were high and similar. Due to the physicochemical homogeneity observed in the Óleo lagoon, the differences between the decay rates of each species are mostly related with detritus chemical quality.

  20. Characterization of Enzymatic profiles of Aedes aegypti strains from the State of Rio Grande do Norte, Brazil

    Directory of Open Access Journals (Sweden)

    Renan Flávio de França Nunes

    2016-01-01

    Full Text Available Abstract This study was conducted in four strains of Aedes aegypti mosquitoes to evaluate the enzymatic activity profiles in the city of Mossoró, Rio Grande do Norte, and correlate them with biochemical mechanisms of resistance to insecticides. Mosquitos were used to quantify the following detoxification enzymes: Mixed-Function Oxidase (MFO, PNPA-esterase (PNPA-EST, and Acetylcholinesterase (AChE. The profiles were compared statistically with profiles from the Rockefeller strain, through the Kruskal-Wallis test and Dunn's multiple comparisons (p 15% and 50%. The statistical analysis revealed significant differences in the MFO and AChE profiles, which are fundamental in the determination of profiles of resistance to insecticides. Three populations were classified as “Substantially changed” for MFO. The altered enzymatic activity showed that the changes could have an important role in exposing resistance to insecticides.