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Sample records for arabinose

  1. L-arabinose fermenting yeast

    Science.gov (United States)

    Zhang, Min; Singh, Arjun; Knoshaug, Eric; Franden, Mary Ann; Jarvis, Eric; Suominen, Pirkko

    2010-12-07

    An L-arabinose utilizing yeast strain is provided for the production of ethanol by introducing and expressing bacterial araA, araB and araD genes. L-arabinose transporters are also introduced into the yeast to enhance the uptake of arabinose. The yeast carries additional genomic mutations enabling it to consume L-arabinose, even as the only carbon source, and to produce ethanol. Methods of producing ethanol include utilizing these modified yeast strains. ##STR00001##

  2. L-arabinose fermenting yeast

    Science.gov (United States)

    Zhang, Min; Singh, Arjun; Suominen, Pirkko; Knoshaug, Eric; Franden, Mary Ann; Jarvis, Eric

    2013-02-12

    An L-arabinose utilizing yeast strain is provided for the production of ethanol by introducing and expressing bacterial araA, araB and araD genes. L-arabinose transporters are also introduced into the yeast to enhance the uptake of arabinose. The yeast carries additional genomic mutations enabling it to consume L-arabinose, even as the only carbon source, and to produce ethanol. A yeast strain engineered to metabolize arabinose through a novel pathway is also disclosed. Methods of producing ethanol include utilizing these modified yeast strains.

  3. Sugar-metal ion interactions: The coordination behavior of cesium ion with lactose, D-arabinose and L-arabinose

    Science.gov (United States)

    Jiang, Ye; Xue, Junhui; Wen, Xiaodong; Zhai, Yanjun; Yang, Limin; Xu, Yizhuang; Zhao, Guozhong; Kou, Kuan; Liu, Kexin; Chen, Jia'er; Wu, Jinguang

    2016-04-01

    The novel cesium chloride-lactose complex (CsCl·C12H22O10 (Cs-Lac), cesium chloride-D-arabinose and L-arabinose complexes (CsCl·C5H10O5, Cs-D-Ara and Cs-L-Ara) have been synthesized and characterized using X-ray diffraction, FTIR, FIR, THz and Raman spectroscopies. Cs+ is 9-coordinated to two chloride ions and seven hydroxyl groups from five lactose molecules in Cs-Lac. In the structures of CsCl-D-arabinose and CsCl-L-arabinose complexes, two kinds of Cs+ ions coexist in the structures. Cs1 is 10-coordinated with two chloride ions and eight hydroxyl groups from five arabinose molecule; Cs2 is 9-coordinated to three chloride ions and six hydroxyl groups from five arabinose molecules. Two coordination modes of arabinose coexist in the structures. α-D-arabinopyranose and α-L-arabinopyranose appear in the structures of Cs-D-Ara and Cs-L-Ara complexes. FTIR and Raman results indicate variations of hydrogen bonds and the conformation of the ligands after complexation. FIR and THz spectra also confirm the formation of Cs-complexes. Crystal structure, FTIR, FIR, THz and Raman spectra provide detailed information on the structure and coordination of hydroxyl groups to metal ions in the cesium chloride-lactose, cesium chloride-D- and L-arabinose complexes.

  4. Metabolic control analysis of Aspergillus niger L-arabinose catabolism

    DEFF Research Database (Denmark)

    de Groot, M.J.L.; Prathumpai, Wai; Visser, J.

    2005-01-01

    -arabinose, a level that resulted in realistic intermediate concentrations in the model, flux control coefficients for L-arabinose reductase, L-arabitol dehydrogenase and L-xylulose reductase were 0.68, 0.17 and 0.14, respectively. The analysis can be used as a guide to identify targets for metabolic engineering......, and their kinetic properties were characterized. For the other enzymes of the pathway the kinetic data were available from the literature. The metabolic model was used to analyze flux and metabolite concentration control of the L-arabinose catabolic pathway. The model demonstrated that flux control does not reside...... at the enzyme following the intermediate with the highest concentration, L-arabitol, but is distributed over the first three steps in the pathway, preceding and following L-arabitol. Flux control appeared to be strongly dependent on the intracellular L-arabinose concentration. At 5 mM intracellular L...

  5. A link between arabinose utilization and oxalotrophy in Bradyrhizobium japonicum.

    Science.gov (United States)

    Koch, Marion; Delmotte, Nathanaël; Ahrens, Christian H; Omasits, Ulrich; Schneider, Kathrin; Danza, Francesco; Padhi, Barnali; Murset, Valérie; Braissant, Olivier; Vorholt, Julia A; Hennecke, Hauke; Pessi, Gabriella

    2014-04-01

    Rhizobia have a versatile catabolism that allows them to compete successfully with other microorganisms for nutrients in the soil and in the rhizosphere of their respective host plants. In this study, Bradyrhizobium japonicum USDA 110 was found to be able to utilize oxalate as the sole carbon source. A proteome analysis of cells grown in minimal medium containing arabinose suggested that oxalate oxidation extends the arabinose degradation branch via glycolaldehyde. A mutant of the key pathway genes oxc (for oxalyl-coenzyme A decarboxylase) and frc (for formyl-coenzyme A transferase) was constructed and shown to be (i) impaired in growth on arabinose and (ii) unable to grow on oxalate. Oxalate was detected in roots and, at elevated levels, in root nodules of four different B. japonicum host plants. Mixed-inoculation experiments with wild-type and oxc-frc mutant cells revealed that oxalotrophy might be a beneficial trait of B. japonicum at some stage during legume root nodule colonization.

  6. Screening and selection of wild strains for L-arabinose isomerase production

    Directory of Open Access Journals (Sweden)

    R. M. Manzo

    2013-12-01

    Full Text Available The majority of L-arabinose isomerases have been isolated by recombinant techniques, but this methodology implies a reduced technological application. For this reason, 29 bacterial strains, some of them previously characterized as L-arabinose isomerase producers, were assayed as L-arabinose fermenting strains by employing conveniently designed culture media with 0.5% (w/v L-arabinose as main carbon source. From all evaluated bacterial strains, Enterococcus faecium DBFIQ ID: E36, Enterococcus faecium DBFIQ ID: ETW4 and Pediococcus acidilactici ATCC ID: 8042 were, in this order, the best L-arabinose fermenting strains. Afterwards, to assay L-arabinose metabolization and L-arabinose isomerase activity, cell-free extract and saline precipitated cell-free extract of the three bacterial cultures were obtained and the production of ketoses was determined by the cysteine carbazole sulfuric acid method. Results showed that the greater the L-arabinose metabolization ability, the higher the enzymatic activity achieved, so Enterococcus faecium DBFIQ ID: E36 was selected to continue with production, purification and characterization studies. This work thus describes a simple microbiological method for the selection of L-arabinose fermenting bacteria for the potential production of the enzyme L-arabinose isomerase.

  7. The effects of L-arabinose on intestinal sucrase activity

    DEFF Research Database (Denmark)

    Krog-Mikkelsen, Inger; Hels, Ole; Tetens, Inge;

    2011-01-01

    On the basis of results in cell cultures, rodents, and pigs, l-arabinose may inhibit intestinal sucrase activity and thereby delay sucrose digestion.......On the basis of results in cell cultures, rodents, and pigs, l-arabinose may inhibit intestinal sucrase activity and thereby delay sucrose digestion....

  8. Improved xylose and arabinose utilization by an industrial recombinant Saccharomyces cerevisiae strain using evolutionary engineering

    DEFF Research Database (Denmark)

    Sanchez, R.G.; Karhumaa, Kaisa; Fonseca, C.;

    2010-01-01

    to improve the simultaneous conversion of xylose and arabinose to ethanol in a recombinant industrial Saccharomyces cerevisiae strain carrying the heterologous genes for xylose and arabinose utilization pathways integrated in the genome. The evolved strain TMB3130 displayed an increased consumption rate......Background: Cost-effective fermentation of lignocellulosic hydrolysate to ethanol by Saccharomyces cerevisiae requires efficient mixed sugar utilization. Notably, the rate and yield of xylose and arabinose co-fermentation to ethanol must be enhanced. Results: Evolutionary engineering was used...... of xylose and arabinose under aerobic and anaerobic conditions. Improved anaerobic ethanol production was achieved at the expense of xylitol and glycerol but arabinose was almost stoichiometrically converted to arabitol. Further characterization of the strain indicated that the selection pressure during...

  9. A mixed diet supplemented with l-arabinose does not alter glycaemic or insulinaemic responses in healthy human subjects

    DEFF Research Database (Denmark)

    Halschou-Jensen, Kia; Knudsen, Knud E Bach; Nielsen, Soren

    2015-01-01

    In addition to a yet-to-be published study showing arabinose to have an inhibiting effect on maltase, in vitro studies have shown L-arabinose to exert an inhibiting effect on small-intestinal sucrase and maltase and the consumption of a sucrose-rich drink containing L-arabinose to exert positive ...

  10. Utilization and Transport of L-Arabinose by Non-Saccharomyces Yeasts

    Energy Technology Data Exchange (ETDEWEB)

    Knoshaug, E. P.; Franden, M. A.; Stambuk, B. U.; Zhang, M.; Singh, A.

    2009-01-01

    L-Arabinose is one of the sugars found in hemicellulose, a major component of plant cell walls. The ability to convert L-arabinose to ethanol would improve the economics of biomass to ethanol fermentations. One of the limitations for L-arabinose fermentation in the current engineered Saccharomyces cerevisiae strains is poor transport of the sugar. To better understand L-arabinose transport and use in yeasts and to identify a source for efficient L-arabinose transporters, 165 non-Saccharomyces yeast strains were studied. These yeast strains were arranged into six groups based on the minimum time required to utilize 20 g/L of L-arabinose. Initial transport rates of L-arabinose were determined for several species and a more comprehensive transport study was done in four selected species. Detailed transport kinetics in Arxula adeninivorans suggested both low and high affinity components while Debaryomyces hansenii var. fabryii, Kluyveromyces marxianus and Pichia guilliermondii possessed a single component, high affinity active transport systems.

  11. Engineering L-arabinose metabolism in triacylglycerol-producing Rhodococcus opacus for lignocellulosic fuel production.

    Science.gov (United States)

    Kurosawa, Kazuhiko; Plassmeier, Jens; Kalinowski, Jörn; Rückert, Christian; Sinskey, Anthony J

    2015-07-01

    Advanced biofuels from lignocellulosic biomass have been considered as a potential solution for the issues of energy sustainability and environmental protection. Triacylglycerols (TAGs) are potential precursors for the production of lipid-based liquid biofuels. Rhodococcus opacus PD630 can accumulate large amounts of TAGs when grown under physiological conditions of high carbon and low nitrogen. However, R. opacus PD630 does not utilize the sugar L-arabinose present in lignocellulosic hydrolysates. Here, we report the engineering of R. opacus to produce TAGs on L-arabinose. We constructed a plasmid (pASC8057) harboring araB, araD and araA genes derived from a Streptomyces bacterium, and introduced the genes into R. opacus PD630. One of the engineered strains, MITAE-348, was capable of growing on high concentrations (up to 100 g/L) of L-arabinose. MITAE-348 was grown in a defined medium containing 16 g/L L-arabinose or a mixture of 8 g/L L-arabinose and 8 g/L D-glucose. In a stationary phase occurring 3 days post-inoculation, the strain was able to completely utilize the sugar, and yielded 2.0 g/L for L-arabinose and 2.2 g/L for L-arabinose/D-glucose of TAGs, corresponding to 39.7% or 42.0%, respectively, of the cell dry weight.

  12. Bioprospecting and evolving alternative xylose and arabinose pathway enzymes for use in Saccharomyces cerevisiae.

    Science.gov (United States)

    Lee, Sun-Mi; Jellison, Taylor; Alper, Hal S

    2016-03-01

    Bioprospecting is an effective way to find novel enzymes from strains with desirable phenotypes. Such bioprospecting has enabled organisms such as Saccharomyces cerevisiae to utilize nonnative pentose sugars. Yet, the efficiency of this pentose catabolism (especially for the case of arabinose) remains suboptimal. Thus, further pathway optimization or identification of novel, optimal pathways is needed. Previously, we identified a novel set of xylan catabolic pathway enzymes from a superior pentose-utilizing strain of Ustilago bevomyces. These enzymes were used to successfully engineer a xylan-utilizing S. cerevisiae through a blended approach of bioprospecting and evolutionary engineering. Here, we expanded this approach to xylose and arabinose catabolic pathway engineering and demonstrated that bioprospected xylose and arabinose catabolic pathways from U. bevomyces offer alternative choices for enabling efficient pentose catabolism in S. cerevisiae. By introducing a novel set of xylose catabolic genes from U. bevomyces, growth rates were improved up to 85 % over a set of traditional Scheffersomyces stipitis pathway genes. In addition, we suggested an alternative arabinose catabolic pathway which, after directed evolution and pathway engineering, enabled S. cerevisiae to grow on arabinose as a sole carbon source in minimal medium with growth rates upwards of 0.05 h(-1). This pathway represents the most efficient growth of yeast on pure arabinose minimal medium. These pathways provide great starting points for further strain development and demonstrate the utility of bioprospecting from U. bevomyces.

  13. The Preparations of L - arabinose%L-阿拉伯糖研究进展

    Institute of Scientific and Technical Information of China (English)

    黄淳

    2011-01-01

    L- arabinose is a new functional and low -caloric sugar. In nature, L -arabinose indwells in the corn bran, beetroot, arabic gum, etc. L- arabinose plays an important role in the modulating of blood sugar and blood fat. The preparation methods of L - arabinose are summarized and the nature of L - arabinose areintrodured in this paper. The article also gives some outlook for the development trend of L -arabinose.%L-阿拉伯糖是一种新兴的低热量功能性糖,在自然界中,广泛存在于玉米皮、甜菜根、阿拉伯胶等中。L-阿拉伯糖在血糖、血脂的调节方面有广阔的前景。本文综述了L-阿拉伯糖的制备方法,并介绍了L-阿拉伯糖的性质,展望了L-阿拉伯糖生产的发展趋势。

  14. L-arabinose pathway engineering for arabitol-free xylitol production in Candida tropicalis.

    Science.gov (United States)

    Yoon, Byoung Hoon; Jeon, Woo Young; Shim, Woo Yong; Kim, Jung Hoe

    2011-04-01

    Xylose reductase (XR) is a key enzyme in biological xylitol production, and most XRs have broad substrate specificities. During xylitol production from biomass hydrolysate, non-specific XRs can reduce L-arabinose, which is the second-most abundant hemicellulosic sugar, to the undesirable byproduct arabitol, which interferes with xylitol crystallization in downstream processing. To minimize the flux from L-arabinose to arabitol, the L-arabinose-preferring, endogenous XR was replaced by a D-xylose-preferring heterologous XR in Candida tropicalis. Then, Bacillus licheniformis araA and Escherichia coli araB and araD were codon-optimized and expressed functionally in C. tropicalis for the efficient assimilation of L-arabinose. During xylitol fermentation, the control strains BSXDH-3 and KNV converted 9.9 g L-arabinose l(-1) into 9.5 and 8.3 g arabitol l(-1), respectively, whereas the recombinant strain JY consumed 10.5 g L-arabinose l(-1) for cell growth without forming arabitol. Moreover, JY produced xylitol with 42 and 16% higher productivity than BSXDH-3 and KNV, respectively.

  15. Co-utilization of L-arabinose and D-xylose by laboratory and industrial Saccharomyces cerevisiae strains

    Directory of Open Access Journals (Sweden)

    Boles Eckhard

    2006-04-01

    Full Text Available Abstract Background Fermentation of lignocellulosic biomass is an attractive alternative for the production of bioethanol. Traditionally, the yeast Saccharomyces cerevisiae is used in industrial ethanol fermentations. However, S. cerevisiae is naturally not able to ferment the pentose sugars D-xylose and L-arabinose, which are present in high amounts in lignocellulosic raw materials. Results We describe the engineering of laboratory and industrial S. cerevisiae strains to co-ferment the pentose sugars D-xylose and L-arabinose. Introduction of a fungal xylose and a bacterial arabinose pathway resulted in strains able to grow on both pentose sugars. Introduction of a xylose pathway into an arabinose-fermenting laboratory strain resulted in nearly complete conversion of arabinose into arabitol due to the L-arabinose reductase activity of the xylose reductase. The industrial strain displayed lower arabitol yield and increased ethanol yield from xylose and arabinose. Conclusion Our work demonstrates simultaneous co-utilization of xylose and arabinose in recombinant strains of S. cerevisiae. In addition, the co-utilization of arabinose together with xylose significantly reduced formation of the by-product xylitol, which contributed to improved ethanol production.

  16. 13C metabolic flux analysis in Clostridium acetobutylicum during growth on L-arabinose

    Science.gov (United States)

    Hurley, Margaret; Sund, Christian; Liu, Sanchao; Germane, Katherine; Servinsky, Matthew; Gerlach, Elliot

    2015-03-01

    Clostridium acetobutylicum's metabolic pathways have been studied for decades due to its metabolic diversity and industrial value, yet many details of its metabolism are continuing to emerge. To elucidate the role of xylulose-5-P/fructose-6-P phosphoketolase (XFP), and the recently discovered Pentose Phosphate Pathway (PKP) in C. acetobutylicum, experimental and computational metabolic isotope analysis was performed under growth on glucose, xylose, and arabinose. Results indicate that PKP utilization increased with increasing xylose concentration and this trend was further pronounced during growth on arabinose. This was confirmed by mutation of the gene encoding XFP, which almost completely abolished flux through the PKP during growth on arabinose and resulted in decreased acetate:butyrate ratios. We discuss these experimental and computational results here, and the implications for our understanding of sugar metabolism in C. acetobutylicum.

  17. A novel method to prepare L-Arabinose from xylose mother liquor by yeast-mediated biopurification

    Directory of Open Access Journals (Sweden)

    Lin Shuangjun

    2011-06-01

    Full Text Available Abstract Background L-arabinose is an important intermediate for anti-virus drug synthesis and has also been used in food additives for diets-controlling in recent years. Commercial production of L-arabinose is a complex progress consisting of acid hydrolysis of gum arabic, followed by multiple procedures of purification, thus making high production cost. Therefore, there is a biotechnological and commercial interest in the development of new cost-effective and high-performance methods for obtaining high purity grade L-arabinose. Results An alternative, economical method for purifying L-arabinose from xylose mother liquor was developed in this study. After screening 306 yeast strains, a strain of Pichia anomala Y161 was selected as it could effectively metabolize other sugars but not L-arabinose. Fermentation in a medium containing xylose mother liquor permitted enrichment of L-arabinose by a significant depletion of other sugars. Biochemical analysis of this yeast strain confirmed that its poor capacity for utilizing L-arabinose was due to low activities of the enzymes required for the metabolism of this sugar. Response surface methodology was employed for optimization the fermentation conditions in shake flask cultures. The optimum conditions were: 75 h fermentation time, at 32.5°C, in a medium containing 21% (v/v xylose mother liquor. Under these conditions, the highest purity of L-arabinose reached was 86.1% of total sugar, facilitating recovery of white crystalline L-arabinose from the fermentation medium by simple methods. Conclusion Yeast-mediated biopurification provides a dynamic method to prepare high purity of L-arabinose from the feedstock solution xylose mother liqour, with cost-effective and high-performance properties.

  18. Engineering of Saccharomyces cerevisiae for Efficient Anaerobic Alcoholic Fermentation of L-Arabinose

    NARCIS (Netherlands)

    Wisselink, H.W.; Toirkens, M.J.; Del Rosario Franco Berriel, M.; Winkler, A.A.; Van Dijken, J.P.; Pronk, J.T.; Van Maris, A.J.A.

    2007-01-01

    For cost-effective and efficient ethanol production from lignocellulosic fractions of plant biomass, the conversion of not only major constituents, such as glucose and xylose, but also less predominant sugars, such as L-arabinose, is required. Wild-type strains of Saccharomyces cerevisiae, the organ

  19. Arabinose and ferulic acid rich pectic polysaccharides extracted from sugar beet pulp.

    NARCIS (Netherlands)

    Oosterveld, A.; Beldman, G.; Schols, H.A.; Voragen, A.G.J.

    1996-01-01

    Arabinose and ferulic acid rich polysaccharides were extracted from sugar beet pulp using two extraction methods: a sequential extraction with H2O (2 times), NaOH/EDTA (2 times), and 4 M NaOH (2 times; method A) and a sequential extraction in which the NaOH/EDTA extraction was replaced by an autocla

  20. Biohydrogen production from arabinose and glucose using extreme thermophilic anaerobic mixed cultures

    DEFF Research Database (Denmark)

    De Abreu, Angela Alexandra Valente; Karakashev, Dimitar Borisov; Angelidaki, Irini;

    2012-01-01

    differences in reactor performance were observed for arabinose and glucose organic loading rates (OLR) ranging from 4.3 to 7.1 kgCOD m-3 d-1. However, for an OLR of 14.2 kgCOD m-3 d-1, hydrogen production rate and hydrogen yield were higher in Rarab than in Rgluc (average hydrogen production rate of 3.2 and 2...... and between the reactors. Increased hydrogen production was observed in batch experiments when hydrogen partial pressure was kept low, both with arabinose and glucose as substrate. Sugars were completely consumed and hydrogen production stimulated (62% higher) when pH 7 was used instead of pH 5.5. Conclusions....... Results Conversion of arabinose and glucose to hydrogen, by extreme thermophilic anaerobic mixed cultures was studied in continuous (70oC, pH 5.5) and batch (70oC, pH 5.5 and pH 7) assays. Two EGSB reactors, Rarab and Rgluc, were continuously fed with arabinose and glucose, respectively. No significant...

  1. Protective effects of L-arabinose in high-carbohydrate, high-fat diet-induced metabolic syndrome in rats

    Directory of Open Access Journals (Sweden)

    Lei Hao

    2015-12-01

    Full Text Available Background: L-Arabinose is a non-caloric sugar, which could affect glucose and lipid metabolism and suppress obesity. However, few reports have described the effect of L-arabinose in metabolic syndrome, a combination of medical disorders that increase the risk of diabetes and cardiovascular disease. Objective: This study was conducted to explore the effects of L-arabinose in rats with metabolic syndrome induced by a high-carbohydrate, high-fat (HCHF diet. Methods: After the rat model for metabolic syndrome was successfully established, L-arabinose was administrated by oral gavage for 6 weeks. The biochemical index and histological analysis were measured, and the expression levels of genes related to fatty acid metabolism were analyzed using real-time PCR. Results: Following treatment with L-arabinose, metabolic syndrome rats had an obvious reduction in body weight, systolic blood pressure, diastolic blood pressure, fasting blood glucose, triglycerides, total cholesterol, serum insulin, TNF-α, and leptin. Further study showed that treatment with L-arabinose significantly increased the expression of mRNA for hepatic CPT-1α and PDK4, but the expression of mRNA for hepatic ACCα was reduced. Conclusions: This work suggests that L-arabinose could lower body weight, Lee's index, and visceral index and improve dyslipidemia, insulin resistance, inflammation, and viscera function, which indicate that it might be a promising candidate for therapies combating metabolic syndrome.

  2. Biohydrogen production from arabinose and glucose using extreme thermophilic anaerobic mixed cultures

    Directory of Open Access Journals (Sweden)

    Abreu Angela A

    2012-02-01

    Full Text Available Abstract Background Second generation hydrogen fermentation technologies using organic agricultural and forestry wastes are emerging. The efficient microbial fermentation of hexoses and pentoses resulting from the pretreatment of lingocellulosic materials is essential for the success of these processes. Results Conversion of arabinose and glucose to hydrogen, by extreme thermophilic, anaerobic, mixed cultures was studied in continuous (70°C, pH 5.5 and batch (70°C, pH 5.5 and pH 7 assays. Two expanded granular sludge bed (EGSB reactors, Rarab and Rgluc, were continuously fed with arabinose and glucose, respectively. No significant differences in reactor performance were observed for arabinose and glucose organic loading rates (OLR ranging from 4.3 to 7.1 kgCOD m-3 d-1. However, for an OLR of 14.2 kgCOD m-3 d-1, hydrogen production rate and hydrogen yield were higher in Rarab than in Rgluc (average hydrogen production rate of 3.2 and 2.0 LH2 L-1 d-1 and hydrogen yield of 1.10 and 0.75 molH2 mol-1substrate for Rarab and Rgluc, respectively. Lower hydrogen production in Rgluc was associated with higher lactate production. Denaturing gradient gel electrophoresis (DGGE results revealed no significant difference on the bacterial community composition between operational periods and between the reactors. Increased hydrogen production was observed in batch experiments when hydrogen partial pressure was kept low, both with arabinose and glucose as substrate. Sugars were completely consumed and hydrogen production stimulated (62% higher when pH 7 was used instead of pH 5.5. Conclusions Continuous hydrogen production rate from arabinose was significantly higher than from glucose, when higher organic loading rate was used. The effect of hydrogen partial pressure on hydrogen production from glucose in batch mode was related to the extent of sugar utilization and not to the efficiency of substrate conversion to hydrogen. Furthermore, at pH 7.0, sugars

  3. Differential effects of mineral and organic acids on the kinetics of arabinose degradation under lignocellulose pretreatment conditions

    NARCIS (Netherlands)

    Kootstra, A.M.J.; Mosier, N.S.; Scott, E.L.; Beeftink, H.H.; Sanders, J.P.M.

    2009-01-01

    Sugar degradation occurs during acid-catalyzed pretreatment of lignocellulosic biomass at elevated temperatures, resulting in degradation products that inhibit microbial fermentation in the ethanol production process. Arabinose, the second most abundant pentose in grasses like corn stover and wheat

  4. Characterisation of the arabinose-rich carbohydrate composition of immature and mature marama beans (Tylosema esculentum).

    Science.gov (United States)

    Mosele, Minah M; Hansen, Ase S; Engelsen, Søren B; Diaz, Jerome; Sørensen, Iben; Ulvskov, Peter; Willats, William G T; Blennow, Andreas; Harholt, Jesper

    2011-08-01

    Marama bean (Tylosema esculentum) is an important component of the diet around the Kalahari Desert in Southern Africa where this drought resistant plant can grow. The marama bean contains roughly 1/3 proteins, 1/3 lipids and 1/3 carbohydrates, but despite its potential as dietary supplement little is known about the carbohydrate fraction. In this study the carbohydrate fraction of "immature" and "mature" marama seeds are characterised. The study shows that the marama bean contains negligible amounts of starch and soluble sugars, both far less than 1%. The cell wall is characterised by a high arabinose content and a high resistance to extraction as even a 6M NaOH extraction was insufficient to extract considerable amounts of the arabinose. The arabinose fraction was characterised by arabinan-like linkages and recognised by the arabinan antibody LM6 and LM13 indicating that it is pectic arabinan. Two pools of pectin could be detected; a regular CDTA (1,2-diaminocyclohexane-N,N,N',N'-tetraacetic acid) or enzymatically extractable pectin fraction and a recalcitrant pectin fraction containing the majority of the arabinans, of which about 40% was unextractable using 6M NaOH. Additionally, a high content of mannose was observed, possibly from mannosylated storage proteins.

  5. The Effect of D-(−-arabinose on Tyrosinase: An Integrated Study Using Computational Simulation and Inhibition Kinetics

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    Hong-Jian Liu

    2012-01-01

    Full Text Available Tyrosinase is a ubiquitous enzyme with diverse physiologic roles related to pigment production. Tyrosinase inhibition has been well studied for cosmetic, medicinal, and agricultural purposes. We simulated the docking of tyrosinase and D-(−-arabinose and found a binding energy of −4.5 kcal/mol for theup-formof D-(−-arabinose and −4.4 kcal/mol for thedown-form of D-(−-arabinose. The results of molecular dynamics simulation suggested that D-(−-arabinose interacts mostly with HIS85, HIS259, and HIS263, which are believed to be in the active site. Our kinetic study showed that D-(−-arabinose is a reversible, mixed-type inhibitor of tyrosinase (α-value =6.11±0.98, Ki=0.21±0.19 M. Measurements of intrinsic fluorescence showed that D-(−-arabinose induced obvious tertiary changes to tyrosinase (binding constant K=1.58±0.02 M−1, binding number n=1.49±0.06. This strategy of predicting tyrosinase inhibition based on specific interactions of aldehyde and hydroxyl groups with the enzyme may prove useful for screening potential tyrosinase inhibitors.

  6. Inoculum type response to different pHs on biohydrogen production from L-arabinose, a component of hemicellulosic biopolymers

    Energy Technology Data Exchange (ETDEWEB)

    Abreu, A.A.; Danko, A.S.; Costa, J.C.; Ferreira, E.C.; Alves, M.M. [IBB - Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, University of Minho, Campus Gualtar, 4710-057 Braga (Portugal)

    2009-02-15

    Biohydrogen production from arabinose was examined using four different anaerobic sludges with different pHs ranging from 4.5 to 8.0. Arabinose (30 g l{sup -1}) was used as the substrate for all experiments. Individual cumulative hydrogen production data was used to estimate the three parameters of the modified Gompertz equation. Higher hydrogen production potentials were observed for higher pH values for all the sludges. G2 (acclimated granular sludge) showed the highest hydrogen production potential and percentage of arabinose consumption compared to the other sludges tested. Granular sludges (G1 and G2) showed different behaviour than the suspended sludges (S1 and S2). The differences were observed to be smaller lag phases, the percentage of acetate produced, the higher percentage of ethanol produced, and the amount of arabinose consumed. A high correlation (R{sup 2} = 0.973) was observed between the percentage of n-butyrate and the percentage of ethanol in G1 sludge, suggesting that ethanol/butyrate fermentation was the dominant fermentative pathway followed by this sludge. In S1, however, the percentage of n-butyrate was highly correlated with the percentage of acetate (R{sup 2} = 0.980). This study indicates that granular sludge can be used for larger pH ranges without reducing its capacity to consume arabinose and achieve higher hydrogen production potentials. (author)

  7. Chlorogenic acid-arabinose hybrid domains in coffee melanoidins: Evidences from a model system.

    Science.gov (United States)

    Moreira, Ana S P; Coimbra, Manuel A; Nunes, Fernando M; Passos, Cláudia P; Santos, Sónia A O; Silvestre, Armando J D; Silva, André M N; Rangel, Maria; Domingues, M Rosário M

    2015-10-15

    Arabinose from arabinogalactan side chains was hypothesized as a possible binding site for chlorogenic acids in coffee melanoidins. To investigate this hypothesis, a mixture of 5-O-caffeoylquinic acid (5-CQA), the most abundant chlorogenic acid in green coffee beans, and (α1 → 5)-L-arabinotriose, structurally related to arabinogalactan side chains, was submitted to dry thermal treatments. The compounds formed during thermal processing were identified by electrospray ionization mass spectrometry (ESI-MS) and characterized by tandem MS (ESI-MS(n)). Compounds composed by one or two CQAs covalently linked with pentose (Pent) residues (1-12) were identified, along with compounds bearing a sugar moiety but composed exclusively by the quinic or caffeic acid moiety of CQAs. The presence of isomers was demonstrated by liquid chromatography online coupled to ESI-MS and ESI-MS(n). Pent1-2CQA were identified in coffee samples. These results give evidence for a diversity of chlorogenic acid-arabinose hybrids formed during roasting, opening new perspectives for their identification in melanoidin structures.

  8. Isolation and identification of arabinose mycolates of Cell Wall Skeleton (CWS) derived from Mycobacterium bovis BCG Tokyo 172 (SMP-105).

    Science.gov (United States)

    Uenishi, Yuko; Kusunose, Naoto; Yano, Ikuya; Sunagawa, Makoto

    2010-03-01

    A unique hydrolysis method using a two-layer solution, consisting of diluted hydrochloric acid and toluene was developed to isolate whole arabinose mycolates from the cell wall skeleton of Mycobacterium bovis BCG Tokyo 172 (SMP-105) in order to reveal its pivotal role in enhancing immune responses against tumors.

  9. Arabinose-rich polymers as an evolutionary strategy to plasticize resurrection plant cell walls against desiccation

    DEFF Research Database (Denmark)

    Moore, John P.; Nguema-Ona, Eric E.; Vicré-Gibouin, Mäite

    2013-01-01

    A variety of Southern African resurrection plants were surveyed using high-throughput cell wall profiling tools. Species evaluated were the dicotyledons, Myrothamnus flabellifolia and Craterostigma plantagineum; the monocotyledons, Xerophyta viscosa, Xerophyta schlecterii, Xerophyta humilis...... and comprehensive microarray polymer profiling in combination with multivariate data analysis. The data obtained suggest that three main functional strategies appear to have evolved to prepare plant cell walls for desiccation. Arabinan-rich pectin and arabinogalactan proteins are found in the resurrection fern M......-like Xerophyta spp. and the resurrection grass E. nindensis were found to contain highly arabinosylated xylans and arabinogalactan proteins. These data support a general mechanism of ‘plasticising’ the cell walls of resurrection plants to desiccation and implicate arabinose-rich polymers (pectin...

  10. Simultaneous utilization of glucose, xylose and arabinose in the presence of acetate by a consortium of Escherichia coli strains

    Directory of Open Access Journals (Sweden)

    Xia Tian

    2012-06-01

    Full Text Available Abstract Background The efficient microbial utilization of lignocellulosic hydrolysates has remained challenging because this material is composed of multiple sugars and also contains growth inhibitors such as acetic acid (acetate. Using an engineered consortium of strains derived from Escherichia coli C and a synthetic medium containing acetate, glucose, xylose and arabinose, we report on both the microbial removal of acetate and the subsequent simultaneous utilization of the sugars. Results In a first stage, a strain unable to utilize glucose, xylose and arabinose (ALS1392, strain E. coli C ptsG manZ glk crr xylA araA removed 3 g/L acetate within 30 hours. In a subsequent second stage, three E. coli strains (ALS1370, ALS1371, ALS1391, which are each engineered to utilize only one sugar, together simultaneously utilized glucose, xylose and arabinose. The effect of non-metabolizable sugars on the metabolism of the target sugar was minimal. Additionally the deletions necessary to prevent the consumption of one sugar only minimally affected the consumption of a desired sugar. For example, the crr deletion necessary to prevent glucose consumption reduced xylose and arabinose utilization by less than 15% compared to the wild-type. Similarly, the araA deletion used to exclude arabinose consumption did not affect xylose- and glucose-consumption. Conclusions Despite the modest reduction in the overall rate of sugar consumption due to the various deletions that were required to generate the consortium of strains, the approach constitutes a significant improvement in any single-organism approach to utilize sugars found in lignocellulosic hydrolysate in the presence of acetate.

  11. Effect of C-terminal protein tags on pentitol and L-arabinose transport by Ambrosiozyma monospora Lat1 and Lat2 transporters in Saccharomyces cerevisiae.

    Science.gov (United States)

    Londesborough, John; Richard, Peter; Valkonen, Mari; Viljanen, Kaarina

    2014-05-01

    Functional expression in heterologous hosts is often less successful for integral membrane proteins than for soluble proteins. Here, two Ambrosiozyma monospora transporters were successfully expressed in Saccharomyces cerevisiae as tagged proteins. Growth of A. monospora on l-arabinose instead of glucose caused transport activities of l-arabinose, l-arabitol, and ribitol, measured using l-[1-(3)H]arabinose, l-[(14)C]arabitol, and [(14)C]ribitol of demonstrated purity. A. monospora LAT1 and LAT2 genes were cloned earlier by using their ability to improve the growth of genetically engineered Saccharomyces cerevisiae on l-arabinose. However, the l-arabinose and pentitol transport activities of S. cerevisiae carrying LAT1 or LAT2 are only slightly greater than those of control strains. S. cerevisiae carrying the LAT1 or LAT2 gene fused in frame to the genes for green fluorescent protein (GFP) or red fluorescent protein (mCherry) or adenylate kinase (AK) exhibited large (>3-fold for LAT1; >20-fold for LAT2) increases in transport activities. Lat1-mCherry transported l-arabinose with high affinity (Km ≈ 0.03 mM) and l-arabitol and ribitol with very low affinity (Km ≥ 75 mM). The Lat2-GFP, Lat2-mCherry, and Lat2-AK fusion proteins could not transport l-arabinose but were high-affinity pentitol transporters (Kms ≈ 0.2 mM). The l-arabinose and pentitol transport activities of A. monospora could not be completely explained by any combination of the observed properties of tagged Lat1 and Lat2, suggesting either that tagging and expression in a foreign membrane alters the transport kinetics of Lat1 and/or Lat2 or that A. monospora contains at least one more l-arabinose transporter.

  12. Identification of GutQ from Escherichia coli as a D-arabinose 5-phosphate isomerase.

    Science.gov (United States)

    Meredith, Timothy C; Woodard, Ronald W

    2005-10-01

    The glucitol operon (gutAEBDMRQ) of Escherichia coli encodes a phosphoenolpyruvate:sugar phosphotransferase system that metabolizes the hexitol D-glucitol (sorbitol). The functions for all but the last gene, gutQ, have been previously assigned. The high sequence similarity between GutQ and KdsD, a D-arabinose 5-phosphate isomerase (API) from the 3-deoxy-D-manno-octulosonate (KDO)-lipopolysaccharide (LPS) biosynthetic pathway, suggested a putative activity, but its role within the context of the gut operon remained unclear. Accordingly, the enzyme was cloned, overexpressed, and characterized. Recombinant GutQ was shown to indeed be a second copy of API from the E. coli K-12 genome with biochemical properties similar to those of KdsD, catalyzing the reversible aldol-ketol isomerization between D-ribulose 5-phosphate (Ru5P) and D-arabinose 5-phosphate (A5P). Genomic disruptions of each API gene were constructed in E. coli K-12. TCM11[(deltakdsD)] was capable of sustaining essential LPS synthesis at wild-type levels, indicating that GutQ functions as an API inside the cell. The gut operon remained inducible in TCM7[(deltagutQ)], suggesting that GutQ is not directly involved in d-glucitol catabolism. The conditional mutant TCM15[(deltagutQdeltakdsD)] was dependent on exogenous A5P both for LPS synthesis/growth and for upregulation of the gut operon. The phenotype was suppressed by complementation in trans with a plasmid encoding a functional copy of GutQ or by increasing the amount of A5P in the medium. As there is no obvious obligatory role for GutQ in the metabolism of d-glucitol and there is no readily apparent link between D-glucitol metabolism and LPS biosynthesis, it is suggested that A5P is not only a building block for KDO biosynthesis but also may be a regulatory molecule involved in expression of the gut operon.

  13. Direct production of D-arabinose from D-xylose by a coupling reaction using D-xylose isomerase, D-tagatose 3-epimerase and D-arabinose isomerase.

    Science.gov (United States)

    Sultana, Ishrat; Mizanur, Rahman Md; Takeshita, Kei; Takada, Goro; Izumori, Ken

    2003-01-01

    Klebsiella pneumoniae 40bXX, a mutant strain that constitutively produces D-arabinose isomerase (D-AI), was isolated through a series of repeated subcultures from the parent strain on a mineral salt medium supplemented with L-Xylose as the sole carbon source. D-AI could be efficiently immobilized on chitopearl beads. The optimum temperature for the activity of the immobilized enzyme was 40 degrees C and the enzyme was stable up to 50 degrees C. The D-Al was active at pH 10.0 and was stable in the range of pH 6.0-11.0. The enzyme required manganese ions for maximum activity. Three immobilized enzymes, D-xylose isomerase (D-XI), D-tagatose 3-epimerase (D-TE and D-AI were used for the preparation of D-arabinose from D-xylose in a coupling reaction. After completion of the reaction, degradation of D-xylulose was carried out by Saccharomyces cerevisiae. The reaction mixture containing D-Xylose, D-ribulose and the product was then separated by ion exchange column chromatography. After crystallization, the product was checked by HPLC, IR spectroscopy, NMR spectroscopy and optical rotation measurements. Finally, 2.0 g of D-arabinose could be obtained from 5 g of the substrate.

  14. L-Ribose production from L-arabinose by immobilized recombinant Escherichia coli co-expressing the L-arabinose isomerase and mannose-6-phosphate isomerase genes from Geobacillus thermodenitrificans.

    Science.gov (United States)

    Kim, Kyoung-Rok; Seo, Eun-Sun; Oh, Deok-Kun

    2014-01-01

    L-Ribose is an important precursor for antiviral agents, and thus its high-level production is urgently demanded. For this aim, immobilized recombinant Escherichia coli cells expressing the L-arabinose isomerase and variant mannose-6-phosphate isomerase genes from Geobacillus thermodenitrificans were developed. The immobilized cells produced 99 g/l L-ribose from 300 g/l L-arabinose in 3 h at pH 7.5 and 60 °C in the presence of 1 mM Co(2+), with a conversion yield of 33 % (w/w) and a productivity of 33 g/l/h. The immobilized cells in the packed-bed bioreactor at a dilution rate of 0.2 h(-1) produced an average of 100 g/l L-ribose with a conversion yield of 33 % and a productivity of 5.0 g/l/h for the first 12 days, and the operational half-life in the bioreactor was 28 days. Our study is first verification for L-ribose production by long-term operation and feasible for cost-effective commercialization. The immobilized cells in the present study also showed the highest conversion yield among processes from L-arabinose as the substrate.

  15. Boric acid as a mobile phase additive for high performance liquid chromatography separation of ribose, arabinose and ribulose.

    Science.gov (United States)

    De Muynck, Cassandra; Beauprez, Joeri; Soetaert, Wim; Vandamme, Erick J

    2006-01-01

    A new high performance liquid chromatographic (HPLC) method is described for the analysis of ribose, arabinose and ribulose mixtures obtained from (bio)chemical isomerization processes. These processes gain importance since the molecules can be used for the synthesis of antiviral therapeutics. The HPLC method uses boric acid as a mobile phase additive to enhance the separation on an Aminex HPX-87K column. By complexing with boric acid, the carbohydrates become negatively charged, thus elute faster from the column by means of ion exlusion and are separated because the complexation capacity with boric acid differs from one carbohydrate to another. Excellent separation between ribose, ribulose and arabinose was achieved with concentrations between 0.1 and 10 gL(-1) of discrete sugar.

  16. Estimation of D-Arabinose by Gas Chromatography/Mass Spectrometry as Surrogate for Mycobacterial Lipoarabinomannan in Human Urine.

    Directory of Open Access Journals (Sweden)

    Prithwiraj De

    Full Text Available Globally, tuberculosis is slowly declining each year and it is estimated that 37 million lives were saved between 2000 and 2013 through effective diagnosis and treatment. Currently, diagnosis relies on demonstration of the bacteria, Mycobacterium tuberculosis (Mtb, in clinical specimens by serial sputum microscopy, culture and molecular testing. Commercial immunoassay lateral flow kits developed to detect Mtb lipoglycan lipoarabinomannan (LAM in urine as a marker of active TB exhibit poor sensitivity, especially in immunocompetent individuals, perhaps due to low abundance of the analyte. Our present study was designed to develop methods to validate the presence of LAM in a quantitative fashion in human urine samples obtained from culture-confirmed TB patients. Herein we describe, a consolidated approach for isolating LAM from the urine and quantifying D-arabinose as a proxy for LAM, using Gas Chromatography/Mass Spectrometry. 298 urine samples obtained from a repository were rigorously analyzed and shown to contain varying amounts of LAM-equivalent ranging between ~10-40 ng/mL. To further substantiate that D-arabinose detected in the samples originated from LAM, tuberculostearic acid, the unique 10-methyloctadecanoic acid present at the phosphatidylinositol end of LAM was also analyzed in a set of samples and found to be present confirming that the D-arabinose was indeed derived from LAM. Among the 144 samples from culture-negative TB suspects, 30 showed presence of D-arabinose suggesting another source of the analyte, such as disseminated TB or from non-tuberculosis mycobacterium. Our work validates that LAM is present in the urine samples of culture-positive patients in small but readily detectable amounts. The study further substantiates LAM in urine as a powerful biomarker for active tuberculosis.

  17. Cloning, Expression, and Characterization of a Novel L-Arabinose Isomerase from the Psychrotolerant Bacterium Pseudoalteromonas haloplanktis.

    Science.gov (United States)

    Xu, Wei; Fan, Chen; Zhang, Tao; Jiang, Bo; Mu, Wanmeng

    2016-11-01

    L-Arabinose isomerase (L-AI, EC 5.3.1.4) catalyzes the isomerization between L-arabinose and L-ribulose, and most of the reported ones can also catalyze D-galactose to D-tagatose, except Bacillus subtilis L-AI. In this article, the L-AI from the psychrotolerant bacterium Pseudoalteromonas haloplanktis ATCC 14393 was characterized. The enzyme showed no substrate specificity toward D-galactose, which was similar to B. subtilis L-AI but distinguished from other reported L-AIs. The araA gene encoding the P. haloplanktis L-AI was cloned and overexpressed in E. coli BL21 (DE3). The recombinant enzyme was purified by one-step nickel affinity chromatography . The enzyme displayed the maximal activity at 40 °C and pH 8.0, and showed more than 75 % of maximal activity from pH 7.5-9.0. Metal ion Mn(2+) was required as optimum metal cofactor for activity simulation, but it did not play a significant role in thermostability improvement as reported previously. The Michaelis-Menten constant (K m), turnover number (k cat), and catalytic efficiency (k cat/K m) for substrate L-arabinose were measured to be 111.68 mM, 773.30/min, and 6.92/mM/min, respectively. The molecular docking results showed that the active site residues of P. haloplanktis L-AI could only immobilize L-arabinose and recognized it as substrate for isomerization.

  18. Negative auto-regulation increases the input dynamic-range of the arabinose system of Escherichia coli

    Directory of Open Access Journals (Sweden)

    Bren Anat

    2011-07-01

    Full Text Available Abstract Background Gene regulation networks are made of recurring regulatory patterns, called network motifs. One of the most common network motifs is negative auto-regulation, in which a transcription factor represses its own production. Negative auto-regulation has several potential functions: it can shorten the response time (time to reach halfway to steady-state, stabilize expression against noise, and linearize the gene's input-output response curve. This latter function of negative auto-regulation, which increases the range of input signals over which downstream genes respond, has been studied by theory and synthetic gene circuits. Here we ask whether negative auto-regulation preserves this function also in the context of a natural system, where it is embedded within many additional interactions. To address this, we studied the negative auto-regulation motif in the arabinose utilization system of Escherichia coli, in which negative auto-regulation is part of a complex regulatory network. Results We find that when negative auto-regulation is disrupted by placing the regulator araC under constitutive expression, the input dynamic range of the arabinose system is reduced by 10-fold. The apparent Hill coefficient of the induction curve changes from about n = 1 with negative auto-regulation, to about n = 2 when it is disrupted. We present a mathematical model that describes how negative auto-regulation can increase input dynamic-range, by coupling the transcription factor protein level to the input signal. Conclusions Here we demonstrate that the negative auto-regulation motif in the native arabinose system of Escherichia coli increases the range of arabinose signals over which the system can respond. In this way, negative auto-regulation may help to increase the input dynamic-range while maintaining the specificity of cooperative regulatory systems. This function may contribute to explaining the common occurrence of negative auto

  19. Crystal Structure of Escherichia coli L-Arabinose Isomerase (ECAI), The Putative Target of Biological Tagatose Production

    Energy Technology Data Exchange (ETDEWEB)

    Manjasetty,B.; Chance, M.

    2006-01-01

    Escherichia coli L-arabinose isomerase (ECAI; EC 5.3.1.4) catalyzes the isomerization of L-arabinose to L-ribulose in vivo. This enzyme is also of commercial interest as it catalyzes the conversion of D-galactose to D-tagatose in vitro. The crystal structure of ECAI was solved and refined at 2.6 Angstroms resolution. The subunit structure of ECAI is organized into three domains: an N-terminal, a central and a C-terminal domain. It forms a crystallographic trimeric architecture in the asymmetric unit. Packing within the crystal suggests the idea that ECAI can form a hexameric assembly. Previous electron microscopic and biochemical studies supports that ECAI is hexameric in solution. A comparison with other known structures reveals that ECAI adopts a protein fold most similar to E. coli fucose isomerase (ECFI) despite very low sequence identity 9.7%. The structural similarity between ECAI and ECFI with regard to number of domains, overall fold, biological assembly, and active site architecture strongly suggests that the enzymes have functional similarities. Further, the crystal structure of ECAI forms a basis for identifying molecular determinants responsible for isomerization of arabinose to ribulose in vivo and galactose to tagatose in vitro.

  20. A unique arabinose 5-phosphate isomerase found within a genomic island associated with the uropathogenicity of Escherichia coli CFT073.

    Science.gov (United States)

    Mosberg, Joshua A; Yep, Alejandra; Meredith, Timothy C; Smith, Sara; Wang, Pan-Fen; Holler, Tod P; Mobley, Harry L T; Woodard, Ronald W

    2011-06-01

    Previous studies showed that deletion of genes c3405 to c3410 from PAI-metV, a genomic island from Escherichia coli CFT073, results in a strain that fails to compete with wild-type CFT073 after a transurethral cochallenge in mice and is deficient in the ability to independently colonize the mouse kidney. Our analysis of c3405 to c3410 suggests that these genes constitute an operon with a role in the internalization and utilization of an unknown carbohydrate. This operon is not found in E. coli K-12 but is present in a small number of pathogenic E. coli and Shigella boydii strains. One of the genes, c3406, encodes a protein with significant homology to the sugar isomerase domain of arabinose 5-phosphate isomerases but lacking the tandem cystathionine beta-synthase domains found in the other arabinose 5-phosphate isomerases of E. coli. We prepared recombinant c3406 protein, found it to possess arabinose 5-phosphate isomerase activity, and characterized this activity in detail. We also constructed a c3406 deletion mutant of E. coli CFT073 and demonstrated that this deletion mutant was still able to compete with wild-type CFT073 in a transurethral cochallenge in mice and could colonize the mouse kidney. These results demonstrate that the presence of c3406 is not essential for a pathogenic phenotype.

  1. Novel transporters from Kluyveromyces marxianus and Pichia guilliermondii expressed in Saccharomyces cerevisiae enable growth on L-arabinose and D-xylose.

    Science.gov (United States)

    Knoshaug, Eric P; Vidgren, Virve; Magalhães, Frederico; Jarvis, Eric E; Franden, Mary Ann; Zhang, Min; Singh, Arjun

    2015-10-01

    Genes encoding L-arabinose transporters in Kluyveromyces marxianus and Pichia guilliermondii were identified by functional complementation of Saccharomyces cerevisiae whose growth on L-arabinose was dependent on a functioning L-arabinose transporter, or by screening a differential display library, respectively. These transporters also transport D-xylose and were designated KmAXT1 (arabinose-xylose transporter) and PgAXT1, respectively. Transport assays using L-arabinose showed that KmAxt1p has K(m) 263 mM and V(max) 57 nM/mg/min, and PgAxt1p has K(m) 0.13 mM and V(max) 18 nM/mg/min. Glucose, galactose and xylose significantly inhibit L-arabinose transport by both transporters. Transport assays using D-xylose showed that KmAxt1p has K(m) 27 mM and V(max) 3.8 nM/mg/min, and PgAxt1p has K(m) 65 mM and V(max) 8.7 nM/mg/min. Neither transporter is capable of recovering growth on glucose or galactose in a S. cerevisiae strain deleted for hexose and galactose transporters. Transport kinetics of S. cerevisiae Gal2p showed K(m) 371 mM and V(max) 341 nM/mg/min for L-arabinose, and K(m) 25 mM and V(max) 76 nM/mg/min for galactose. Due to the ability of Gal2p and these two newly characterized transporters to transport both L-arabinose and D-xylose, one scenario for the complete usage of biomass-derived pentose sugars would require only the low-affinity, high-throughput transporter Gal2p and one additional high-affinity general pentose transporter, rather than dedicated D-xylose or L-arabinose transporters. Additionally, alignment of these transporters with other characterized pentose transporters provides potential targets for substrate recognition engineering.

  2. Crystallization and preliminary X-ray crystallographic analysis of L-arabinose isomerase from thermophilic Geobacillus kaustophilus.

    Science.gov (United States)

    Cao, Thinh-Phat; Choi, Jin Myung; Lee, Sang-Jae; Lee, Yong-Jik; Lee, Sung-Keun; Jun, Youngsoo; Lee, Dong-Woo; Lee, Sung Haeng

    2014-01-01

    L-arabinose isomerase (AI), which catalyzes the isomerization of L-arabinose to L-ribulose, can also convert D-galactose to D-tagatose, a natural sugar replacer, which is of commercial interest in the food and healthcare industries. Intriguingly, mesophilic and thermophilic AIs showed different substrate preferences and metal requirements in catalysis and different thermostabilities. However, the catalytic mechanism of thermophilic AIs still remains unclear. Therefore, thermophilic Geobacillus kaustophilus AI (GKAI) was overexpressed, purified and crystallized, and a preliminary X-ray diffraction data set was obtained. Diffraction data were collected from a GKAI crystal to 2.70 Å resolution. The crystal belonged to the monoclinic space group C2, with unit-cell parameters a = 224.12, b = 152.95, c = 91.28 Å, β = 103.61°. The asymmetric unit contained six molecules, with a calculated Matthews coefficient of 2.25 Å(3) Da(-1) and a solvent content of 45.39%. The three-dimensional structure determination of GKAI is currently in progress by molecular replacement and model building.

  3. The Hypocrea jecorina (syn. Trichoderma reesei) lxr1 gene encodes a D-mannitol dehydrogenase and is not involved in L-arabinose catabolism

    NARCIS (Netherlands)

    Metz, Benjamin; de Vries, Ronald P; Polak, Stefan; Seidl, Verena; Seiboth, Bernhard

    2009-01-01

    The Hypocrea jecorina LXR1 was described as the first fungal L-xylulose reductase responsible for NADPH dependent reduction of L-xylulose to xylitol in L-arabinose catabolism. Phylogenetic analysis now reveals that LXR1 forms a clade with fungal D-mannitol 2-dehydrogenases. Lxr1 and the orthologous

  4. The acid-tolerant L-arabinose isomerase from the mesophilic Shewanella sp. ANA-3 is highly active at low temperatures

    Directory of Open Access Journals (Sweden)

    Rhimi Moez

    2011-11-01

    Full Text Available Abstract Background L-arabinose isomerases catalyse the isomerization of L-arabinose into L-ribulose at insight biological systems. At industrial scale of this enzyme is used for the bioconversion of D-galactose into D-tagatose which has many applications in pharmaceutical and agro-food industries. The isomerization reaction is thermodynamically equilibrated, and therefore the bioconversion rates is shifted towards tagatose when the temperature is increased. Moreover, to prevent secondary reactions it will be of interest to operate at low pH. The profitability of this D-tagatose production process is mainly related to the use of lactose as cheaper raw material. In many dairy products it will be interesting to produce D-tagatose during storage. This requires an efficient L-arabinose isomerase acting at low temperature and pH values. Results The gene encoding the L-arabinose isomerase from Shewanella sp. ANA-3 was cloned and overexpressed in Escherichia coli. The purified protein has a tetrameric arrangement composed by four identical 55 kDa subunits. The biochemical characterization of this enzyme showed that it was distinguishable by its maximal activity at low temperatures comprised between 15-35°C. Interestingly, this biocatalyst preserves more than 85% of its activity in a broad range of temperatures from 4.0 to 45°C. Shewanella sp. ANA-3 L-arabinose isomerase was also optimally active at pH 5.5-6.5 and maintained over 80% of its activity at large pH values from 4.0 to 8.5. Furthermore, this enzyme exhibited a weak requirement for metallic ions for its activity evaluated at 0.6 mM Mn2+. Stability studies showed that this protein is highly stable mainly at low temperature and pH values. Remarkably, T268K mutation clearly enhances the enzyme stability at low pH values. Use of this L-arabinose isomerase for D-tagatose production allows the achievement of attractive bioconversion rates of 16% at 4°C and 34% at 35°C. Conclusions Here we

  5. Increased urinary excretion of analogs of Krebs cycle metabolites and arabinose in two brothers with autistic features.

    Science.gov (United States)

    Shaw, W; Kassen, E; Chaves, E

    1995-08-01

    A marked increase in analogs of Krebs cycle metabolites was found in the urine of two brothers with autistic features. These metabolites included citramalic, tartaric (3-OH-malic), and 3-oxoglutaric acids and compounds tentatively identified as a citric acid analog and partially identified as a phenylcarboxylic acid by the fragmentation pattern of the trimethylsilyl (TMS) derivatives of the compounds and mass shifts of the same compounds derivatized with perdeuterated N,O-bis(trimethylsilyl)trifluoroacetamide. The molecular mass of the TMS derivative of the tentatively identified citric acid analog was 596 Da, based on a finding of a significant M - 15 ion at m/z 581. The citric acid analog was excreted in quantities as high as 137 mmol/mol creatinine, based on the response factor of citric acid as a surrogate calibrator. A carbohydrate with a retention time and mass spectrum identical to arabinose was also found in high concentrations in the urine of these brothers.

  6. Characterization of a F280N variant of L-arabinose isomerase from Geobacillus thermodenitrificans identified as a D-galactose isomerase.

    Science.gov (United States)

    Kim, Baek-Joong; Hong, Seung-Hye; Shin, Kyung-Chul; Jo, Ye-Seul; Oh, Deok-Kun

    2014-11-01

    The double-site variant (C450S-N475K) L-arabinose isomerase (L-AI) from Geobacillus thermodenitrificans catalyzes the isomerization of D-galactose to D-tagatose, a functional sweetener. Using a substrate-docking homology model, the residues near to D-galactose O6 were identified as Met186, Phe280, and Ile371. Several variants obtained by site-directed mutagenesis of these three residues were analyzed, and a triple-site (F280N) variant enzyme exhibited the highest activity for D-galactose isomerization. The k cat/K m of the triple-site variant enzyme for D-galactose was 2.1-fold higher than for L-arabinose, whereas the k cat/K m of the double-site variant enzyme for L-arabinose was 43.9-fold higher than for D-galactose. These results suggest that the triple-site variant enzyme is a D-galactose isomerase. The conversion rate of D-galactose to D-tagatose by the triple-site variant enzyme was approximately 3-fold higher than that of the double-site variant enzyme for 30 min. However, the conversion yields of L-arabinose to L-ribulose by the triple-site and double-site variant enzymes were 10.6 and 16.0 % after 20 min, respectively. The triple-site variant enzyme exhibited increased specific activity, turnover number, catalytic efficiency, and conversion rate for D-galactose isomerization compared to the double-site variant enzyme. Therefore, the amino acid at position 280 determines the substrate specificity for D-galactose and L-arabinose, and the triple-site variant enzyme has the potential to produce D-tagatose on an industrial scale.

  7. A single and two step isomerization process for d-tagatose and l-ribose bioproduction using l-arabinose isomerase and d-lyxose isomerase.

    Science.gov (United States)

    Patel, Manisha J; Akhani, Rekha C; Patel, Arti T; Dedania, Samir R; Patel, Darshan H

    2017-02-01

    l-ribose and d-tagatose are biochemically synthesized using sugar isomerases. The l-arabinose isomerase gene from Shigella flexneri (Sf-AI) was cloned and expressed in Escherichia coli BL-21. Sf-AI was applied for the bioproduction of d-tagatose from d-galactose. l-ribose synthesis was performed by two step isomerization using Sf-AI and d-lyxose/ribose isomerase from Cohnella laevoribosii. The overall 22.3% and 25% conversion rate were observed for d-tagatose and l-ribose production from d-galactose and l-arabinose respectively. In the present manuscript, synthesis of rare sugars from naturally available sugars is discussed along with the biochemical characterization of Sf-AI and its efficiency.

  8. Targeted deletion of the ara operon of Salmonella typhimurium enhances L-arabinose accumulation and drives PBAD-promoted expression of anti-cancer toxins and imaging agents.

    Science.gov (United States)

    Hong, Hyun; Lim, Daejin; Kim, Geun-Joong; Park, Seung-Hwan; Sik Kim, Hyeon; Hong, Yeongjin; Choy, Hyon E; Min, Jung-Joon

    2014-01-01

    Tumor-specific expression of antitumor drugs can be achieved using attenuated Salmonella typhimurium harboring the PBAD promoter, which is induced by L-arabinose. However, L-arabinose does not accumulate because it is metabolized to D-xylulose-5-P by enzymes encoded by the ara operon in Salmonellae. To address this problem, we developed an engineered strain of S. typhimurium in which the ara operon is deleted. Linear DNA transformation was performed using λ red recombinase to exchange the ara operon with linear DNA carrying an antibiotic-resistance gene with homology to regions adjacent to the ara operon. The ara operon-deleted strain and its parental strain were transformed with a plasmid encoding Renilla luciferase variant 8 (RLuc8) or cytolysin A (clyA) under the control of the PBAD promoter. Luciferase assays demonstrated that RLuc8 expression was 49-fold higher in the ara operon-deleted S. typhimurium than in the parental strain after the addition of L-arabinose. In vivo bioluminescence imaging showed that the tumor tissue targeted by the ara operon-deleted Salmonella had a stronger imaging signal (~30-fold) than that targeted by the parental strain. Mice with murine colon cancer (CT26) that had been injected with the ara operon-deleted S. typhimurium expressing clyA showed significant tumor suppression. The present report demonstrates that deletion of the ara operon of S. typhimurium enhances L-arabinose accumulation and thereby drives PBAD-promoted expression of cytotoxic agents and imaging agents. This is a promising approach for tumor therapy and imaging.

  9. XacR - a novel transcriptional regulator of D-xylose and L-arabinose catabolism in the haloarchaeon Haloferax volcanii.

    Science.gov (United States)

    Johnsen, Ulrike; Sutter, Jan-Moritz; Schulz, Anne-Christine; Tästensen, Julia-Beate; Schönheit, Peter

    2015-05-01

    The haloarchaeon Haloferax volcanii degrades D-xylose and L-arabinose via oxidative pathways to α-ketoglutarate. The genes involved in these pathways are clustered and were transcriptionally upregulated by both D-xylose and L-arabinose suggesting a common regulator. Adjacent to the gene cluster, a putative IclR-like transcriptional regulator, HVO_B0040, was identified. It is shown that HVO_B0040, designated xacR, encodes an activator of both D-xylose and L-arabinose catabolism: in ΔxacR cells, transcripts of genes involved in pentose catabolism could not be detected; transcript formation could be recovered by complementation, indicating XacR dependent transcriptional activation. Upstream activation promoter regions and nucleotide sequences that were essential for XacR-mediated activation of pentose-specific genes were identified by in vivo deletion and scanning mutagenesis. Besides its activator function XacR acted as repressor of its own synthesis: xacR deletion resulted in an increase of xacR promoter activity. A palindromic sequence was identified at the operator site of xacR promoter, and mutation of this sequence also resulted in an increase and thus derepression of xacR promoter activity. It is concluded that the palindromic sequence represents the binding site of XacR as repressor. This is the first report of a transcriptional regulator of pentose catabolism in the domain of archaea.

  10. Arabinan-deficient mutants of Corynebacterium glutamicum and the consequent flux in decaprenylmonophosphoryl-D-arabinose metabolism.

    Science.gov (United States)

    Alderwick, Luke J; Dover, Lynn G; Seidel, Mathias; Gande, Roland; Sahm, Hermann; Eggeling, Lothar; Besra, Gurdyal S

    2006-11-01

    The arabinogalactan (AG) of Corynebacterianeae is a critical macromolecule that tethers mycolic acids to peptidoglycan, thus forming a highly impermeable cell wall matrix termed the mycolyl-arabinogalactan peptidoglycan complex (mAGP). The front line anti-tuberculosis drug, ethambutol (Emb), targets the Mycobacterium tuberculosis and Corynebacterium glutamicum arabinofuranosyltransferase Mt-EmbA, Mt-EmbB and Cg-Emb enzymes, respectively, which are responsible for the biosynthesis of the arabinan domain of AG. The substrate utilized by these important glycosyltransferases, decaprenylmonophosphoryl-D-arabinose (DPA), is synthesized via a decaprenylphosphoryl-5-phosphoribose (DPPR) synthase (UbiA), which catalyzes the transfer of 5-phospho-ribofuranose-pyrophosphate (pRpp) to decaprenol phosphate to form DPPR. Glycosyl compositional analysis of cell walls extracted from a C. glutamicum::ubiA mutant revealed a galactan core consisting of alternating beta(1-->5)-Galf and beta(1-->6)-Galf residues, completely devoid of arabinan and a concomitant loss of cell-wall-bound mycolic acids. In addition, in vitro assays demonstrated a complete loss of arabinofuranosyltransferase activity and DPA biosynthesis in the C. glutamicum::ubiA mutant when supplemented with p[14C]Rpp, the precursor of DPA. Interestingly, in vitro arabinofuranosyltransferase activity was restored in the C. glutamicum::ubiA mutant when supplemented with exogenous DP[14C]A substrate, and C. glutamicum strains deficient in ubiA, emb, and aftA all exhibited different levels of DPA biosynthesis.

  11. A combination of l-arabinose and chromium lowers circulating glucose and insulin levels after an acute oral sucrose challenge

    Directory of Open Access Journals (Sweden)

    Perricone Nicholas V

    2011-05-01

    Full Text Available Abstract Background A growing body of research suggests that elevated circulating levels of glucose and insulin accelerate risk factors for a wide range of disorders. Low-risk interventions that could suppress glucose without raising insulin levels could offer significant long-term health benefits. Methods To address this issue, we conducted two sequential studies, the first with two phases. In the first phase of Study 1, baseline fasting blood glucose was measured in 20 subjects who consumed 70 grams of sucrose in water and subsequently completed capillary glucose measurements at 30, 45, 60 and 90 minutes (Control. On day-2 the same procedure was followed, but with subjects simultaneously consuming a novel formula containing l-arabinose and a trivalent patented food source of chromium (LA-Cr (Treatment. The presence or absence of the LA-Cr was blinded to the subjects and testing technician. Comparisons of changes from baseline were made between Control and Treatment periods. In the second phase of Study 1, 10 subjects selected from the original 20 competed baseline measures of body composition (DXA, a 43-blood chemistry panel and a Quality of Life Inventory. These subjects subsequently took LA-Cr daily for 4 weeks completing daily tracking forms and repeating the baseline capillary tests at the end of each of the four weeks. In Study 2, the same procedures used in the first phase were repeated for 50 subjects, but with added circulating insulin measurements at 30 and 60 minutes from baseline. Results In both studies, as compared to Control, the Treatment group had significantly lower glucose responses for all four testing times (AUC = P P = Conclusions As compared to a placebo control, consumption of a LA-Cr formula after a 70-gram sucrose challenge was effective in safely lowering both circulating glucose and insulin levels. Trial Registration Clinical Trials.gov, NCT0110743

  12. L-阿拉伯糖的功能特性与应用%The function characteristics and applications of L- Arabinose

    Institute of Scientific and Technical Information of China (English)

    孙鲁; 聂永来; 崔淑芬

    2011-01-01

    As a pentose and new type of low - calorie sweetener, L - Arabinose can inhibit the metabolism ot sucrose,control blood glucose elevation and lipid accumulation, prevent constipation, promote the growth of Bacillus bifidus, alter the composition of skeletal muscle fiber. This paper reports the function characteristics of L- Arabinose, also introduces the applications in bakery, drinking and biomedicine. L- Arabinose, as a versatile new resource food, has profound influence on the improvement of dietary structure and quality of life, the market prospect is capacious.%作为五碳糖的L-阿拉伯糖,是一种新型的低热量甜味剂,具有抑制人体对蔗糖的代谢与吸收、控制血糖升高和脂肪堆积、预防便秘、促进双歧杆菌生长、改变骨骼肌纤维成分等性质.本文介绍了L-阿拉伯糖的性质、功能和在焙烤食品、饮品和生物医药方面的应用情况,得出L-阿拉伯糖作为一种用途广泛的新资源食品,对于改善人们的饮食结构、提高人们的生活品质将会产生深远的影响,市场前景广阔.

  13. Downregulation of the UDP-arabinomutase gene in switchgrass (Panicum virgatum L. results in increased cell wall lignin while reducing arabinose-glycans

    Directory of Open Access Journals (Sweden)

    Jonathan Duran Willis

    2016-10-01

    Full Text Available Switchgrass (Panicum virgatum L. is a C4 perennial prairie grass and a lignocellulosic biofuels feedstock. Saccharification and biofuel yields are inhibited by the plant cell wall’s natural recalcitrance against enzymatic degradation. Plant hemicellulose polysaccharides such as arabinoxylans structurally support and crosslink other cell wall polymers. Grasses have predominately Type II cell walls that are abundant in arabinoxylan, which comprise nearly 25% of aboveground biomass. A primary component of arabinoxylan synthesis is uridine diphosphate (UDP linked to arabinofuranose (Araf. A family of UDP-arabinopyranose mutase/reversible glycosylated polypeptides (UAM/RGPs catalyze the interconversion between UDP-arabinopyranose (UDP-Arap and UDP-Araf. In switchgrass we knocked down expression of the endogenous PvUAM1 gene via RNAi to investigate its role in cell wall recalcitrance in the feedstock. PvUAM1 encodes a switchgrass homolog of UDP-arabinose mutase, which converts UDP-Arap to UDP-Araf. Each transgenic line contained between one to at least seven T-DNA insertions, resulting in some cases, a 95% reduction of native PvUAM1 transcript in stem internodes. Transgenic plants had increased pigmentation in vascular tissues at nodes, but were otherwise morphologically similar to non-transgenics. There was decreased cell wall-associated arabinose in leaves and stems by over 50%, but there was an increase in cellulose in these organs. In addition, there was a commensurate change in arabinose side chain extension. Cell wall lignin composition was altered with a concurrent increase in lignin content and transcript abundance of lignin biosynthetic genes in mature tillers. Enzymatic saccharification efficiency was unchanged in the transgenic plants relative to the control, but had increased glucose in cell walls. The increased glucose detected in stems and leaves indicates that attenuation of PvUAM1 expression might have downstream effects on starch

  14. Downregulation of a UDP-Arabinomutase Gene in Switchgrass (Panicum virgatum L.) Results in Increased Cell Wall Lignin While Reducing Arabinose-Glycans

    Science.gov (United States)

    Willis, Jonathan D.; Smith, James A.; Mazarei, Mitra; Zhang, Ji-Yi; Turner, Geoffrey B.; Decker, Stephen R.; Sykes, Robert W.; Poovaiah, Charleson R.; Baxter, Holly L.; Mann, David G. J.; Davis, Mark F.; Udvardi, Michael K.; Peña, Maria J.; Backe, Jason; Bar-Peled, Maor; Stewart, C. N.

    2016-01-01

    Background: Switchgrass (Panicum virgatum L.) is a C4 perennial prairie grass and a dedicated feedstock for lignocellulosic biofuels. Saccharification and biofuel yields are inhibited by the plant cell wall’s natural recalcitrance against enzymatic degradation. Plant hemicellulose polysaccharides such as arabinoxylans structurally support and cross-link other cell wall polymers. Grasses predominately have Type II cell walls that are abundant in arabinoxylan, which comprise nearly 25% of aboveground biomass. A primary component of arabinoxylan synthesis is uridine diphosphate (UDP) linked to arabinofuranose (Araf). A family of UDP-arabinopyranose mutase (UAM)/reversible glycosylated polypeptides catalyze the interconversion between UDP-arabinopyranose (UDP-Arap) and UDP-Araf. Results: The expression of a switchgrass arabinoxylan biosynthesis pathway gene, PvUAM1, was decreased via RNAi to investigate its role in cell wall recalcitrance in the feedstock. PvUAM1 encodes a switchgrass homolog of UDP-arabinose mutase, which converts UDP-Arap to UDP-Araf. Southern blot analysis revealed each transgenic line contained between one to at least seven T-DNA insertions, resulting in some cases, a 95% reduction of native PvUAM1 transcript in stem internodes. Transgenic plants had increased pigmentation in vascular tissues at nodes, but were otherwise similar in morphology to the non-transgenic control. Cell wall-associated arabinose was decreased in leaves and stems by over 50%, but there was an increase in cellulose. In addition, there was a commensurate change in arabinose side chain extension. Cell wall lignin composition was altered with a concurrent increase in lignin content and transcript abundance of lignin biosynthetic genes in mature tillers. Enzymatic saccharification efficiency was unchanged in the transgenic plants relative to the control. Conclusion: Plants with attenuated PvUAM1 transcript had increased cellulose and lignin in cell walls. A decrease in cell

  15. Cloning of araA Gene Encoding L-Arabinose Isomerase from Marine Geobacillus stearothermophilus Isolated from Tanjung Api, Poso, Indonesia

    Directory of Open Access Journals (Sweden)

    DEWI FITRIANI

    2010-06-01

    Full Text Available L-arabinose isomerase is an enzyme converting D-galactose to D-tagatose. D-tagatose is a potential sweetener-sucrose substitute which has low calorie. This research was to clone and sequence araA gene from marine bacterial strain Geobacillus stearothermophilus isolated from Tanjung Api Poso Indonesia. The amplified araA gene consisted of 1494 bp nucleotides encoding 497 amino acids. DNA alignment analysis showed that the gene had high homology with that of G. stearothermophilus T6. The enzyme had optimum activity at high temperature and alkalin condition.

  16. Molecular characterization of two Arabidopsis thaliana glycosyltransferase mutants, rra1 and rra2, which have a reduced residual arabinose content in a polymer tightly associated with the cellulosic wall residue

    DEFF Research Database (Denmark)

    Egelund, Jack; Obel, Nicolai; Ulvskov, Peter

    2007-01-01

    Two putative glycosyltransferases in Arabidopsis thaliana, designated reduced residual arabinose-1 and -2 (RRA1 and RRA2), are characterized at the molecular level. Both genes are classified in CAZy GT-family-77 and are phylogenetically related to putative glycosyltranferases of Chlamydomonas...... identified and characterized at the molecular and biochemical level. Monosaccharide compositional analyses of cell wall material isolated from the meristematic region showed a ca. 20% reduction in the arabinose content in the insoluble/undigested cell wall residue after enzymatic removal of xyloglucan...... and pectic polysaccharides. These data indicate that both RRA-1 and -2 play a role in the arabinosylation of cell wall component(s)....

  17. KINETIKA FERMENTASI PADA PRODUKSI XILITOL DENGAN PENAMBAHAN ARABINOSA DAN GLUKOSA SEBAGAI KOSUBSTRAT OLEH Candida shehatae WAY 08 [A Kinetic Study of Xylitol Production with Glucose and Arabinose as Cosubstrate by Candida shehatae WAY 08

    Directory of Open Access Journals (Sweden)

    Wisnu Adi Yulianto1

    2005-12-01

    Full Text Available Xylitol production by Candida shehatae WAY 08 was investigated under two sets of conditions (a with addition of glucose or arabinose as cosubstrate, (b ratio of xylose to cosubstrate at the range of 6:1— 6:3%. The fermentation was performed at 3000/n 500 ml Erlenmeyer flasks placed in a shaker incubator at 200 rpm for 72 h. Biornass concentration was calculated as dry mass. Xylose. cosubstrate. xylitol, ethanol, and acetic acid concentrator ware determined using API. C.The result indicated that addition of arabinose as cosubstrate to xylose within the ratio range of 1:6—3:6% could increase xylitol production. The highest xylitol yield (0,84 gIg and volumetric rate of xylitol production (0.66 g/Lh were achieved at ratio of xylose to arabinose as high as 6:1%. However, addition of glucose as cosubstrate decreased xylitul production. A medium containing 6% glucose as a sole carbon source could achieve the hiqhest ethanol yield(0.32 g/g and growth yièld (0,21/ gIg. wh;/e arabinose as a sole source was metabolized mainly for biomoss formation.

  18. Genetic Interaction of Aspergillus nidulans galR, xlnR and araR in Regulating D-Galactose and L-Arabinose Release and Catabolism Gene Expression

    NARCIS (Netherlands)

    Kowalczyk, Joanna E; Gruben, Birgit S; Battaglia, Evy; Wiebenga, Ad; Majoor, Eline; de Vries, Ronald P

    2015-01-01

    In Aspergillus nidulans, the xylanolytic regulator XlnR and the arabinanolytic regulator AraR co-regulate pentose catabolism. In nature, the pentose sugars D-xylose and L-arabinose are both main building blocks of the polysaccharide arabinoxylan. In pectin and arabinogalactan, these two monosacchari

  19. L-阿拉伯糖对代谢综合征大鼠糖脂代谢的影响%Effect of L-Arabinose on glucolipid metabolism in metabolic syndrome rats

    Institute of Scientific and Technical Information of China (English)

    李凯; 吕晓玲; 张婷婷; 王婷婷

    2013-01-01

    目的:观察L-阿拉伯糖对代谢综合征(MS)大鼠糖脂代谢的影响.方法:通过给予健康雄性SD大鼠高糖高脂高盐饮食14w,建立MS大鼠模型.筛选建模成功的MS大鼠,将其随机分为模型对照组和L-阿拉伯糖低剂量组、中剂量组、高剂量组,给予不同剂量L-阿拉伯糖溶液灌胃6w,检测各组大鼠空腹血糖(FBG)及血清TG、TC、HDL-C、LDL-C、游离脂肪酸(FFA)水平.结果:与模型对照组相比,L-阿拉伯糖可以不同程度地降低血清TG、TC、LDL-C水平,降低血清FFA含量,同时可以明显改善FBG水平.结论:L-阿拉伯糖可以通过降低FBG水平和改善脂代谢紊乱来缓解MS大鼠的症状.%Objective:To evaluate the effect of L-arabinose on glucolipid metabolism in metabolic syndrome rats.Methods:Metabolic syndrome rats models were induced by feeding with high sugar-high fat-high salt diet for 14 weeks.The rats were then divided into four groups randomLy:model control group and low dosage L-arabinose group,the medium dosage L-arabinose group,high dosage L-arabinose group.Three doses of L-arabinose solution were given by intragastric administration for 6 weeks.Fasting plasma glucose,the levels of TG,TC,HDL-C,LDL-C,free fatty acids in ser-um of each group rats were measured.Results:Compared with the model control rats,L-arabinose could reduce the levels of TG,TC,and LDL-C in serum and reduce the content of free fatty acids in serum.Meanwhile,L-arabinose could significantly improve the level of fasting plasma glucose.Conclusions:L-arabinnose could relieve the symptoms of MS rats through reducing fasting blood glucose level and improving lipid metabolic disorder.

  20. Kinetics of oxidation of D-arabinose and D-xylose by vanadium (V in the presence of manganese II as homogeneous catalyst

    Directory of Open Access Journals (Sweden)

    Ezekiel O. Odebunmi

    2010-12-01

    Full Text Available Kinetics of oxidation of D-arabinose and D-xylose by acidic solution of vanadium (V ions in the presence of manganese (II has been reported. First-order dependence of the reaction rate was observed on [sugars] and [H+] at low concentrations throughout the oxidation reaction and a zero-order dependence on [sugar] and [H+] was observed at high concentrations. First-order kinetics with respect to [Mn (II] was also observed throughout the oxidation for both sugars. The results indicate the effect of Cl- concentration is negligible. The reaction rates increase with the ionic strength of the medium. Various activation parameters were evaluated and provide further support to the proposed mechanism. Formic acid was reported as one of the oxidation products of these sugars.

  1. Characterization of a recombinant L-fucose isomerase from Caldicellulosiruptor saccharolyticus that isomerizes L-fucose, D-arabinose, D-altrose, and L-galactose.

    Science.gov (United States)

    Ju, Yo-Han; Oh, Deok-Kun

    2010-02-01

    A recombinant L-fucose isomerase from Caldicellulosiruptor saccharolyticus was purified as a single 68 kDa band with an activity of 76 U mg(-1). The molecular mass of the native enzyme was 204 kDa as a trimer. The maximum activity for L-fucose isomerization was at pH 7 and 75 degrees C in the presence of 1 mM Mn(2+). Its half-life at 70 degrees C was 6.1 h. For aldose substrates, the enzyme displayed activity in decreasing order for L-fucose, with a k (cat) of 11,910 min(-1) and a K (m) of 140 mM, D-arabinose, D-altrose, and L-galactose. These aldoses were converted to the ketoses L-fuculose, D-ribulose, D-psicose, and L-tagatose, respectively, with 24, 24, 85, 55% conversion yields after 3 h.

  2. A method for the production of D-tagatose using a recombinant Pichia pastoris strain secreting β-D-galactosidase from Arthrobacter chlorophenolicus and a recombinant L-arabinose isomerase from Arthrobacter sp. 22c

    Directory of Open Access Journals (Sweden)

    Wanarska Marta

    2012-08-01

    Full Text Available Abstract Background D-Tagatose is a natural monosaccharide which can be used as a low-calorie sugar substitute in food, beverages and pharmaceutical products. It is also currently being tested as an anti-diabetic and obesity control drug. D-Tagatose is a rare sugar, but it can be manufactured by the chemical or enzymatic isomerization of D-galactose obtained by a β-D-galactosidase-catalyzed hydrolysis of milk sugar lactose and the separation of D-glucose and D-galactose. L-Arabinose isomerases catalyze in vitro the conversion of D-galactose to D-tagatose and are the most promising enzymes for the large-scale production of D-tagatose. Results In this study, the araA gene from psychrotolerant Antarctic bacterium Arthrobacter sp. 22c was isolated, cloned and expressed in Escherichia coli. The active form of recombinant Arthrobacter sp. 22c L-arabinose isomerase consists of six subunits with a combined molecular weight of approximately 335 kDa. The maximum activity of this enzyme towards D-galactose was determined as occurring at 52°C; however, it exhibited over 60% of maximum activity at 30°C. The recombinant Arthrobacter sp. 22c L-arabinose isomerase was optimally active at a broad pH range of 5 to 9. This enzyme is not dependent on divalent metal ions, since it was only marginally activated by Mg2+, Mn2+ or Ca2+ and slightly inhibited by Co2+ or Ni2+. The bioconversion yield of D-galactose to D-tagatose by the purified L-arabinose isomerase reached 30% after 36 h at 50°C. In this study, a recombinant Pichia pastoris yeast strain secreting β-D-galactosidase Arthrobacter chlorophenolicus was also constructed. During cultivation of this strain in a whey permeate, lactose was hydrolyzed and D-glucose was metabolized, whereas D-galactose was accumulated in the medium. Moreover, cultivation of the P. pastoris strain secreting β-D-galactosidase in a whey permeate supplemented with Arthrobacter sp. 22c L-arabinose isomerase resulted in a 90% yield

  3. [Screening of food-grade microorganisms for biotransformation of D-tagatose and cloning and expression of L-arabinose isomerase].

    Science.gov (United States)

    Men, Yan; Zhu, Yueming; Guan, Yuping; Zhang, Tongcun; Izumori, Ken; Sun, Yuanxia

    2012-05-01

    L-Arabinose isomerase (L-AI) is an intracellular enzyme that catalyzes the reversible isomerization of D-galactose and D-tagatose. Given the widespread use of D-tagatose in the food industry, food-grade microorganisms and the derivation of L-AI for the production of D-tagatose is gaining increased attention. In the current study, food-grade strains from different foods that can convert D-galactose to D-tagatose were screened. According to physiological, biochemical, and 16S rDNA gene analyses, the selected strain was found to share 99% identity with Pediococcus pentosaceus, and was named as Pediococcus pentosaceus PC-5. The araA gene encoding L-AI from Pediococcus pentosaceus PC-5 was cloned and overexpressed in E. coli BL21. The yield of D-tagatose using D-galactose as the substrate catalyzed by the crude enzyme in the presence of Mn2+ was found to be 33% at 40 degrees C.

  4. Molecular characterization of a thermostable L-fucose isomerase from Dictyoglomus turgidum that isomerizes L-fucose and D-arabinose.

    Science.gov (United States)

    Hong, Seung-Hye; Lim, Yu-Ri; Kim, Yeong-Su; Oh, Deok-Kun

    2012-09-01

    A recombinant thermostable l-fucose isomerase from Dictyoglomus turgidum was purified with a specific activity of 93 U/mg by heat treatment and His-trap affinity chromatography. The native enzyme existed as a 410 kDa hexamer. The maximum activity for l-fucose isomerization was observed at pH 7.0 and 80 °C with a half-life of 5 h in the presence of 1 mM Mn(2+) that was present one molecular per monomer. The isomerization activity of the enzyme with aldose substrates was highest for l-fucose (with a k(cat) of 15,500 min(-1) and a K(m) of 72 mM), followed by d-arabinose, d-altrose, and l-galactose. The 15 putative active-site residues within 5 Å of the substrate l-fucose in the homology model were individually replaced with other amino acids. The analysis of metal-binding capacities of these alanine-substituted variants revealed that Glu349, Asp373, and His539 were metal-binding residues, and His539 was the most influential residue for metal binding. The activities of all variants at 349 and 373 positions except for a dramatically decreased k(cat) of D373A were completely abolished, suggesting that Glu349 and Asp373 were catalytic residues. Alanine substitutions at Val131, Met197, Ile199, Gln314, Ser405, Tyr451, and Asn538 resulted in substantial increases in K(m), suggesting that these amino acids are substrate-binding residues. Alanine substitutions at Arg30, Trp102, Asn404, Phe452, and Trp510 resulted in decreases in k(cat), but had little effect on K(m).

  5. The solution structure of double helical arabino nucleic acids (ANA and 2'F-ANA): effect of arabinoses in duplex-hairpin interconversion.

    Science.gov (United States)

    Martín-Pintado, Nerea; Yahyaee-Anzahaee, Maryam; Campos-Olivas, Ramón; Noronha, Anne M; Wilds, Christopher J; Damha, Masad J; González, Carlos

    2012-10-01

    We report here the first structure of double helical arabino nucleic acid (ANA), the C2'-stereoisomer of RNA, and the 2'-fluoro-ANA analogue (2'F-ANA). A chimeric dodecamer based on the Dickerson sequence, containing a contiguous central segment of arabino nucleotides, flanked by two 2'-deoxy-2'F-ANA wings was studied. Our data show that this chimeric oligonucleotide can adopt two different structures of comparable thermal stabilities. One structure is a monomeric hairpin in which the stem is formed by base paired 2'F-ANA nucleotides and the loop by unpaired ANA nucleotides. The second structure is a bimolecular duplex, with all the nucleotides (2'F-ANA and ANA) forming Watson-Crick base pairs. The duplex structure is canonical B-form, with all arabinoses adopting a pure C2'-endo conformation. In the ANA:ANA segment, steric interactions involving the 2'-OH substituent provoke slight changes in the glycosidic angles and, therefore, in the ANA:ANA base pair geometry. These distortions are not present in the 2'F-ANA:2'F-ANA regions of the duplex, where the -OH substituent is replaced by a smaller fluorine atom. 2'F-ANA nucleotides adopt the C2'-endo sugar pucker and fit very well into the geometry of B-form duplex, allowing for favourable 2'F···H8 interactions. This interaction shares many features of pseudo-hydrogen bonds previously observed in 2'F-ANA:RNA hybrids and in single 2'F-ANA nucleotides.

  6. The influence of Aspergillus niger transcription factors AraR and XlnR in the gene expression during growth in D-xylose, L-arabinose and steam-exploded sugarcane bagasse.

    Science.gov (United States)

    de Souza, Wagner Rodrigo; Maitan-Alfenas, Gabriela Piccolo; de Gouvêa, Paula Fagundes; Brown, Neil Andrew; Savoldi, Marcela; Battaglia, Evy; Goldman, Maria Helena S; de Vries, Ronald P; Goldman, Gustavo Henrique

    2013-11-01

    The interest in the conversion of plant biomass to renewable fuels such as bioethanol has led to an increased investigation into the processes regulating biomass saccharification. The filamentous fungus Aspergillus niger is an important microorganism capable of producing a wide variety of plant biomass degrading enzymes. In A. niger the transcriptional activator XlnR and its close homolog, AraR, controls the main (hemi-)cellulolytic system responsible for plant polysaccharide degradation. Sugarcane is used worldwide as a feedstock for sugar and ethanol production, while the lignocellulosic residual bagasse can be used in different industrial applications, including ethanol production. The use of pentose sugars from hemicelluloses represents an opportunity to further increase production efficiencies. In the present study, we describe a global gene expression analysis of A. niger XlnR- and AraR-deficient mutant strains, grown on a D-xylose/L-arabinose monosaccharide mixture and steam-exploded sugarcane bagasse. Different gene sets of CAZy enzymes and sugar transporters were shown to be individually or dually regulated by XlnR and AraR, with XlnR appearing to be the major regulator on complex polysaccharides. Our study contributes to understanding of the complex regulatory mechanisms responsible for plant polysaccharide-degrading gene expression, and opens new possibilities for the engineering of fungi able to produce more efficient enzymatic cocktails to be used in biofuel production.

  7. Genetic Interaction of Aspergillus nidulans galR, xlnR and araR in Regulating D-Galactose and L-Arabinose Release and Catabolism Gene Expression.

    Science.gov (United States)

    Kowalczyk, Joanna E; Gruben, Birgit S; Battaglia, Evy; Wiebenga, Ad; Majoor, Eline; de Vries, Ronald P

    2015-01-01

    In Aspergillus nidulans, the xylanolytic regulator XlnR and the arabinanolytic regulator AraR co-regulate pentose catabolism. In nature, the pentose sugars D-xylose and L-arabinose are both main building blocks of the polysaccharide arabinoxylan. In pectin and arabinogalactan, these two monosaccharides are found in combination with D-galactose. GalR, the regulator that responds to the presence of D-galactose, regulates the D-galactose catabolic pathway. In this study we investigated the possible interaction between XlnR, AraR and GalR in pentose and/or D-galactose catabolism in A. nidulans. Growth phenotypes and metabolic gene expression profiles were studied in single, double and triple disruptant A. nidulans strains of the genes encoding these paralogous transcription factors. Our results demonstrate that AraR and XlnR not only control pentose catabolic pathway genes, but also genes of the oxido-reductive D-galactose catabolic pathway. This suggests an interaction between three transcriptional regulators in D-galactose catabolism. Conversely, GalR is not involved in regulation of pentose catabolism, but controls only genes of the oxido-reductive D-galactose catabolic pathway.

  8. Genetic Interaction of Aspergillus nidulans galR, xlnR and araR in Regulating D-Galactose and L-Arabinose Release and Catabolism Gene Expression.

    Directory of Open Access Journals (Sweden)

    Joanna E Kowalczyk

    Full Text Available In Aspergillus nidulans, the xylanolytic regulator XlnR and the arabinanolytic regulator AraR co-regulate pentose catabolism. In nature, the pentose sugars D-xylose and L-arabinose are both main building blocks of the polysaccharide arabinoxylan. In pectin and arabinogalactan, these two monosaccharides are found in combination with D-galactose. GalR, the regulator that responds to the presence of D-galactose, regulates the D-galactose catabolic pathway. In this study we investigated the possible interaction between XlnR, AraR and GalR in pentose and/or D-galactose catabolism in A. nidulans. Growth phenotypes and metabolic gene expression profiles were studied in single, double and triple disruptant A. nidulans strains of the genes encoding these paralogous transcription factors. Our results demonstrate that AraR and XlnR not only control pentose catabolic pathway genes, but also genes of the oxido-reductive D-galactose catabolic pathway. This suggests an interaction between three transcriptional regulators in D-galactose catabolism. Conversely, GalR is not involved in regulation of pentose catabolism, but controls only genes of the oxido-reductive D-galactose catabolic pathway.

  9. Stable zymomonas mobilis xylose and arabinose fermenting strains

    Science.gov (United States)

    Zhang, Min; Chou, Yat-Chen

    2008-04-08

    The present invention briefly includes a transposon for stable insertion of foreign genes into a bacterial genome, comprising at least one operon having structural genes encoding enzymes selected from the group consisting of xylAxylB, araBAD and tal/tkt, and at least one promoter for expression of the structural genes in the bacterium, a pair of inverted insertion sequences, the operons contained inside the insertion sequences, and a transposase gene located outside of the insertion sequences. A plasmid shuttle vector for transformation of foreign genes into a bacterial genome, comprising at least one operon having structural genes encoding enzymes selected from the group consisting of xylAxylB, araBAD and tal/tkt, at least one promoter for expression of the structural genes in the bacterium, and at least two DNA fragments having homology with a gene in the bacterial genome to be transformed, is also provided.The transposon and shuttle vectors are useful in constructing significantly different Zymomonas mobilis strains, according to the present invention, which are useful in the conversion of the cellulose derived pentose sugars into fuels and chemicals, using traditional fermentation technology, because they are stable for expression in a non-selection medium.

  10. Engineering Pseudomonas putida S12 for efficient utilization of D-Xylose and L-Arabinose

    NARCIS (Netherlands)

    Meijnen, J.P.; Winde, J.H. de; Ruijssenaars, H.J.

    2008-01-01

    The solvent-tolerant bacterium Pseudomonas putida S12 was engineered to utilize xylose as a substrate by expressing xylose isomerase (XylA) and xylulokinase (XylB) from Escherichia coli. The initial yield on xylose was low (9% [g CDW g substrate−1], where CDW is cell dry weight), and the growth rate

  11. Arabinose content of arabinoxylans contributes to flexibility of acetylated arabinoxylan films

    NARCIS (Netherlands)

    Stepan, A.M.; Hoïje, A.; Schols, H.A.; Waard, de P.; Gatenholm, P.

    2012-01-01

    Arabinoxylans (AX) from rye were partly debranched by chemical hydrolysis methods, and AXs differing in arabinosyl substitution were acetylated using chemical methods. The resulting materials are film forming, and these films underwent molecular structural analysis and were tested for their material

  12. The effects of combined catalysis of oxalic acid and seawater on the kinetics of xylose and arabinose dehydration to furfural

    NARCIS (Netherlands)

    Hongsiri, W.; Danon, B.; De Jong, W.

    2014-01-01

    It is known that both acids and salts have a positive catalytic effect on the dehydration of pentoses to form furfural, a potentially attractive platform chemical. In this study the effects of the combined usage of an organic acid, instead of stronger mineral acids, and a saline catalyst is investig

  13. A synthetic arabinose-inducible promoter confers high levels of recombinant protein expression in hyperthermophilic archaeon Sulfolobus islandicus

    DEFF Research Database (Denmark)

    Peng, Nan; Deng, Ling; Mei, Yuxia;

    2012-01-01

    levels of target gene expression. More strikingly, N-terminal amino acid sequencing of recombinant proteins unraveled that the protein synthesized from pEXA-N-lacS lacked the designed 6×His tag and that translation initiation did not start at the ATG codon of the fusion gene. Instead, it started...

  14. A Series of Medium and High Copy Number Arabinose-Inducible Escherichia coli Expression Vectors Compatible with pBR322 and pACYC184

    OpenAIRE

    Chakravartty, Vandana; Cronan, John E.

    2015-01-01

    The original pBAD24 plasmid and the derived lower copy number (the pBAD322 series) expression vectors have been widely used in Escherichia coli, Salmonella enterica, and related bacteria. However, a flexible pBAD expression system has been available only in pMB1 (ColE1) vectors. We report a series of pBAD vectors that replicate using the origin of plasmid RSF1030 that are compatible with pMB1 (ColE1) and p15A (pACYC) vectors. Both high (≥pBAD24) and medium (~pBAD322) copy number plasmids enco...

  15. Aldopentoses in the Gas Phase: Rotational Spectra of D-Xylose D-Arabinose D-Lyxose and 2-DEOXY-D-RIBOSE

    Science.gov (United States)

    Pena, I.; Cabezas, C.; Daly, A. M.; Bermudez, C.; Mata, S.; Blanco, S.; Lopez, J. C.; Alonso, J. L.

    2013-06-01

    A new experimental approach chirped-pulse Fourier transform microwave (CP-FTMW) spectrometer combined with a laser ablation (LA) source has been used to investigate the conformational distribution of aldopentoses. From their laser ablated crystalline solids, two conformers of α-D-xylopyranose, four of β-D-arabinopyranose, five of β-D-lyxopyranose and two α- and four β- of 2-deoxy-D -ribopyranose have been identified in the supersonic jet on the basis of the experimental rotational constants extracted from the analysis of the spectra. The five monosubstituted ^{13}C species of the most abundant conformer of D-xylopyranose have been observed in their natural abundance, taking advantage of the sensitivity of our spectrometer. The anomeric effect and cooperative hydrogen bonding have been found to be the main factors which control the conformational behavior of the observed conformers. G. G. Brown, B. C. Dian, K. O. Douglass, S. M. Geyer, S. T. Shipman, B. H. Pate, Rev. Sci. Instrum. 2008, 79, 053103. S. Mata, I. Peña, C. Cabezas, J. C. López, J. L. Alonso, J. Mol. Spectrosc. 2012, 280, 91.

  16. 微生物酶解法产生阿拉伯糖——菌种筛选与初步鉴定%Microbial Production of Arabinose:(I)Screening and Identification of Strains

    Institute of Scientific and Technical Information of China (English)

    周俊; 徐畅; 浦佳; 彭哲初; 邓亚卉; 徐洁; 贾香清; 郑珩

    2010-01-01

    使用半纤维素平板法从土壤分离菌中筛选到产半纤维素酶活较高的真菌.将这些菌株在含玉米芯半纤维素的培养基中发酵,鉴定发酵液中还原糖产量,从中筛选出3株产还原糖较多的菌.将其发酵产物经柱前衍生,HPLC检测,发现其中DHC菌株的发酵产物以木糖和阿拉伯糖为主,而培养基中的葡萄糖大部分被利用,可用于发酵法联产阿拉伯糖和木糖.对DHC菌株通过菌落形态、孢子形态以及ITS区基因序列测序分析,初步确定该菌为亮白曲霉 (Aspergillus candidus).对于亮白曲霉产生的半纤维素酶国内外尚较少研究报导,可为开发利用新的微生物资源奠定基础.

  17. The Microbial Degradation of TCE (Trichloroethylene).

    Science.gov (United States)

    1987-04-01

    Production Voges-Proskaver Test Gelatin Hydrolysis Utilization of: Citratea Glucose + Mannitol + Sorbitol + Rhamnose + Amygdalin + Arabinose + a. Strain was...Methanol Glucose + Citrate + 1,2-Dichloroethane 1,2-Dibromoethane Mannitol + Inositol Sorbitol + Rhamnose + Sucrose Melibiose + Amygdalin + Arabinose

  18. Rapid Dispersion of Polymicrobial Wound Biofilms with Depolymerase Enzymes

    Science.gov (United States)

    2013-11-01

    found in 6 of 8 strains, while arabinose, fucose , rhamnose, and xylose were found in 5 of 8 strains. For linkage analysis, 33 distinct residue...6 of 8 strains while arabinose, fucose , rhamnose, and xylose were found in 5 of 8 strains. In contrast, N-acetyl- galactosamine (GalNAc) was only...latter contained trace amounts of arabinose, fucose , and xylose, which were all absent in the former. Thus, in instances where our data differ from

  19. Alpha-L-Arabinofuranosidases: The potential applications in biotechnology

    Digital Repository Service at National Institute of Oceanography (India)

    Numan, M.Th.; Bhosle, N.B.

    treatment, juice clarification, quality of animal feedstock, production of bioethanol and the synthesis of oligosaccharides etc. Production of arabinose as antiglycemic agent: Recently, there is a growing interest for L-arabinose as a possible food... in preventing postprandial hyperglycemia in diabetic patients [104*]. Therefore, effective L-arabinose production is a vital perquisite for its use in this respect as well as for its importance in food industry. To achieve this goal, it is necessary to use...

  20. Effect of adding oxidated chicken fat to D-Arabinose/L-Cysteine reaction system on chicken flavor%加入氧化鸡脂对D-阿拉伯糖/L-半胱氨酸Maillard反应生成鸡肉风味的影响

    Institute of Scientific and Technical Information of China (English)

    李阳; 金青哲; 罗昌荣; 王兴国

    2008-01-01

    加入氧化鸡油到D-阿拉伯糖/L-半胱氨酸的Maillard反应体系中,采用固相微萃取和气质联用的方法,研究氧化鸡脂对鸡肉风味的影响.反应体系为:(1)空白(D-阿拉伯糖/L-半胱氨酸的Maillard反应),(2)加入未氧化鸡脂到Maillard反应体系,(3)加入氧化鸡脂到Maillard反应体系,(4)MaiUard反应后加入氧化鸡脂,(5)Maillard反应后加入氧化鸡脂并在60℃下保持30min.结果表明,加入鸡脂参与Maillard反应可产生大量的挥发性风味物质,尤其是加入氧化鸡脂,所得到的呋喃、噻吩、酸、含硫物质和噻唑等挥发性组分的种类最多.

  1. Enhancement of xylose utilization from corn stover by a recombinant bacterium for ethanol production

    Science.gov (United States)

    Effects of substrate-selective inoculum prepared by growing on glucose, xylose, arabinose, GXA (glucose, xylose, arabinose, 1:1:1) and corn stover hydrolyzate (dilute acid pretreated and enzymatically hydrolyzed, CSH) on ethanol production from CSH by a mixed sugar utilizing recombinant Escherichia ...

  2. NCBI nr-aa BLAST: CBRC-BTAU-01-2762 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-BTAU-01-2762 ref|NP_809349.1| arabinose-proton symporter [Bacteroides thetaiotao...micron VPI-5482] gb|AAO75543.1| arabinose-proton symporter [Bacteroides thetaiotaomicron VPI-5482] NP_809349.1 1.9 26% ...

  3. NCBI nr-aa BLAST: CBRC-TTRU-01-0812 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-TTRU-01-0812 ref|ZP_04048216.1| arabinose efflux permease family protein [Brachyspira murdoch...ii DSM 12563] gb|EEK07851.1| arabinose efflux permease family protein [Brachyspira murdochii DSM 12563] ZP_04048216.1 0.009 28% ...

  4. Novel monosaccharide fermentation products in Caldicellulosiruptor saccharolyticus identified using NMR spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Isern, Nancy G.; Xue, Junfeng; Rao, Jaya V.; Cort, John R.; Ahring, Birgitte K.

    2013-04-03

    Profiles of metabolites produced by the thermophilic obligately anaerobic cellulose-degrading Gram-positive bacterium Caldicellulosiruptor saccharolyticus DSM 8903 strain following growth on different monosaccharides (D-glucose, D-mannose, L-arabinose, D-arabinose, D-xylose, L-fucose, and D-fucose) as carbon sources revealed several unexpected fermentation products, suggesting novel metabolic capacities and unexplored metabolic pathways in this organism. Both 1H and 13C nuclear magnetic resonance (NMR) spectroscopy were used to determine intracellular and extracellular metabolite profiles. Metabolite profiles were determined from 1-D 1H NMR spectra by curve fitting against spectral libraries provided in Chenomx software. To reduce uncertainties due to unassigned, overlapping, or poorly-resolved peaks, metabolite identifications were confirmed with 2-D homonuclear and heteronuclear NMR experiments. In addition to expected metabolites such as acetate, lactate, glycerol, and ethanol, several novel fermentation products were identified: ethylene glycol (from growth on D-arabinose, though not L-arabinose), acetoin and 2,3-butanediol (from D-glucose and L-arabinose), and hydroxyacetone (from D-mannose and L-arabinose). Production of ethylene glycol from D-arabinose was particularly notable, with around 10% of the substrate carbon converted into this uncommon fermentation product. The novel products have not previously been reported to be produced by C. saccharolyticus, nor would they be easily predicted from the current genome annotation, and show new potentials for using this strain for production of bioproducts.

  5. Monosaccharide composition of suspended particles from the Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Bhosle, N.B.; Sankaran, P.D.; Wagh, A.B.

    , fucose, ribose, arabinose and xylose showed large variations and were generally abundant at greater depths ( 100 m). Glucose contribution to the total carbohydrates, especially at higher depths ( 100 m) was relatively less than that reported from other...

  6. Extracellular polymeric substances of the marine fouling diatom Amphora rostrata Wm. Sm.

    Digital Repository Service at National Institute of Oceanography (India)

    Khandeparker, R.; Bhosle, N.B.

    the presence of a single peak. Capillary gas chromatographic analysis of both planktonic and biofilm EPS showed that fucose (36.7%) and galactose (27.6%) were the most abundant monosaccharides, with small quantities of rhamnose, xylose, arabinose, mannose...

  7. Enhancement of xylose utilization from corn stover by a recombinant Escherichia coli strain for ethanol production.

    Science.gov (United States)

    Saha, Badal C; Qureshi, Nasib; Kennedy, Gregory J; Cotta, Michael A

    2015-08-01

    Effects of substrate-selective inoculum prepared by growing on glucose, xylose, arabinose, GXA (glucose, xylose, arabinose, 1:1:1) and corn stover hydrolyzate (dilute acid pretreated and enzymatically hydrolyzed, CSH) on ethanol production from CSH by a mixed sugar utilizing recombinant Escherichia coli (strain FBR5) were investigated. The initial ethanol productivity was faster for the seed grown on xylose followed by GXA, CSH, glucose and arabinose. Arabinose grown seed took the longest time to complete the fermentation. Delayed saccharifying enzyme addition in simultaneous saccharification and fermentation of dilute acid pretreated CS by the recombinant E. coli strain FBR5 allowed the fermentation to finish in a shorter time than adding the enzyme simultaneously with xylose grown inoculum. Use of substrate selective inoculum and fermenting pentose sugars first under glucose limited condition helped to alleviate the catabolite repression of the recombinant bacterium on ethanol production from lignocellulosic hydrolyzate.

  8. Distribution and seasonal variation of concentrations of particulate carbohydrates and uronic acids in the northern Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Khodse, V.B.; Fernandes, L.; Gopalakrishna, V.V.; Bhosle, N.B.; Fernandes, V.; Matondkar, S.G.P.; Bhushan, R.

    decreased with the increasing water depth. Generally, high C:N ratios were associated with low yields of carbohydrates and uronic acids. Inverse correlation between the mole fractions of arabinose plus xylose and rhamnose plus fucose indicates the importance...

  9. Biogeochemical characteristics of sedimenting particles in Dona Paula Bay, India

    Digital Repository Service at National Institute of Oceanography (India)

    DeSouza, F.P.; Garg, A.; Bhosle, N.B.

    percentage distribution of ribose plus fucose, as well as arabinose plus galactose in a sugar fraction (calculated without glucose) to dis- tinguishplantmaterial,bacteria,phytoplanktonandzoo- plankton sources in suspended and sedimented materials 2.1. Study.... As the study site could not be approached during southwest monsoon and sediment samples. Relative inputs from calcareous and siliceous test material in sediment trap samples have been characterized using the arabinose/fucose ratio (Ittekkot, Deuser, & Degens...

  10. Metabolic engineering of Arabidopsis for butanetriol production using bacterial genes.

    Science.gov (United States)

    Abdel-Ghany, Salah E; Day, Irene; Heuberger, Adam L; Broeckling, Corey D; Reddy, Anireddy S N

    2013-11-01

    1,2,4-butanetriol (butanetriol) is a useful precursor for the synthesis of the energetic material butanetriol trinitrate and several pharmaceutical compounds. Bacterial synthesis of butanetriol from xylose or arabinose takes place in a pathway that requires four enzymes. To produce butanetriol in plants by expressing bacterial enzymes, we cloned native bacterial or codon optimized synthetic genes under different promoters into a binary vector and stably transformed Arabidopsis plants. Transgenic lines expressing introduced genes were analyzed for the production of butanetriol using gas chromatography coupled to mass spectrometry (GC-MS). Soil-grown transgenic plants expressing these genes produced up to 20 µg/g of butanetriol. To test if an exogenous supply of pentose sugar precursors would enhance the butanetriol level, transgenic plants were grown in a medium supplemented with either xylose or arabinose and the amount of butanetriol was quantified. Plants expressing synthetic genes in the arabinose pathway showed up to a forty-fold increase in butanetriol levels after arabinose was added to the medium. Transgenic plants expressing either bacterial or synthetic xylose pathways, or the arabinose pathway showed toxicity symptoms when xylose or arabinose was added to the medium, suggesting that a by-product in the pathway or butanetriol affected plant growth. Furthermore, the metabolite profile of plants expressing arabinose and xylose pathways was altered. Our results demonstrate that bacterial pathways that produce butanetriol can be engineered into plants to produce this chemical. This proof-of-concept study for phytoproduction of butanetriol paves the way to further manipulate metabolic pathways in plants to enhance the level of butanetriol production.

  11. Arabinoxylan-degrading enzyme system of the fungus Aspergillus awamori: purification and properties of an alpha-L-arabinofuranosidase.

    Science.gov (United States)

    Wood, T M; McCrae, S I

    1996-05-01

    An alpha-L-arabinofuranosidase produced by the fungus Aspergillus awamori had a molecular mass of approximately 64 kDa on sodium dodecyl sulphate/polyacrylamide gel electrophoresis (SDS-PAGE) and was optimally active at pH 4.6 and 50 degrees C. The enzyme, which chromatographed as a single component on SDS-PAGE, appeared to consist of two isoenzymes of pI 3.6 and 3.2. Acting in isolation, the alpha-L-arabinofuranosidase had only a very limited capacity to release L-arabinose (less than 11%) directly from arabinoxylans that had been extracted from a number of plant cell wall preparations using 18% alkali, but a much higher proportion of the L-arabinose (46%) was released from a wheat straw arabinoxylan that had been isolated by steam treatment. There was a marked synergistic effect between the alpha-L-arabinofuranosidase and an endo-(1 --> 4)-beta-D-xylanase produced by A. awamori in both the rate and extent of the release of L-arabinose from both oat straw and wheat straw arabinoxylans, suggesting that L-arabinose-substituted oligosaccharides generated by the endoxylanase action were better substrates for enzyme action. A novel property of the alpha-L-arabinofuranosidase was its capacity to release a substantial proportion (42%) of feruloyl L-arabinose from intact wheat straw arabinoxylan. The concerted action of the alpha-L-arabinofuranosidase and endoxylanase released 71% of the feruloyl L-arabinose and 69% of the p-coumaroyl L-arabinose substituents from wheat straw arabinoxylan.

  12. Preliminary study of polysaccharides in the tragacanth of Astragalus gossipinus Fisch and Astragalus keyserlingii Bunge

    Directory of Open Access Journals (Sweden)

    H. Ebrahimzadeh F. Mighani

    1997-08-01

    Full Text Available From the point of gum production, Fabaceae is one of the most richest plant families. Tragacanth is one of the most important gums and has medicianl, industrial and food applications. The soluble and insoloble fractions are 40 and 60% in white gum and 70 and 30% in yellow gum, respectively. These fractions do not show considerable seasonal variations. Total sugar in white gum and yellow gum are 70% and 90% , respectively; monosaccharides in both kind of tragacanths include galacturonic acid, galactose, glucose, arabinose, xylose, fucose, and rhamnose and the amount of xylose in the composition is higher than that of others. Insoluble fraction of white gum, the amount of xylose is more than that of arabinose pJus fucose while in yellow gum its amount is lower than that of arabinose plus fucose. fln insoluble fraction of both kind of tragacanths, the amount of arabinose plus fucose is high. The quality of white gum, in comparison to yellow gum, is better due to the higher in soluble fraction and arabinose plus fucose to xylose in this fraction . The gum tragacartti of both species has a xylan backbone.

  13. Extracellular polysaccharide composition of Azospirillum brasilense and its relation with cell aggregation.

    Science.gov (United States)

    Burdman, S; Jurkevitch, E; Soria-Díaz, M E; Serrano, A M; Okon, Y

    2000-08-15

    The exopolysaccharide (EPS) and capsular polysaccharide (CPS) composition of four Azospirillum brasilense strains differing in their aggregation capacity was analyzed by high performance anion exchange chromatography. When growing the different strains in an aggregation inducing medium containing a high carbon:nitrogen (C:N) ratio, both EPS and CPS showed a positive correlation between aggregation and the relative amount of arabinose. Arabinose was not detected in polysaccharides from Sp72002, a pleiotrophic Tn5 mutant strain impaired in aggregation. Arabinose was also not detected in extracellular polysaccharides of bacteria grown in a low C:N ratio, non-inducing aggregation medium, with exception for a relatively small amount found in the CPS of FAJ0204, a super-aggregating mutant strain. The only monosaccharides able to significantly inhibit aggregation at low sugar concentration when tested in a bioassay were arabinose (at a higher extent) and galactose. The possibility that residues of arabinose present in the extracellular polysaccharides are involved in the aggregation of A. brasilense is discussed.

  14. Quinoa (Chenopodium quinoa W.) and amaranth (Amaranthus caudatus L.) provide dietary fibres high in pectic substances and xyloglucans.

    Science.gov (United States)

    Lamothe, Lisa M; Srichuwong, Sathaporn; Reuhs, Bradley L; Hamaker, Bruce R

    2015-01-15

    Dietary fibre of quinoa and amaranth was analysed for its insoluble and soluble fibre content, composition, and structure. Total dietary fibre content was 10% for quinoa and 11% for amaranth. For both pseudocereals, 78% of its dietary fibre was insoluble. Insoluble fibre (IDF) from quinoa and amaranth was mainly composed of galacturonic acid, arabinose, galactose, xylose and glucose. Linkage analysis indicated that IDF was composed of homogalacturonans and rhamnogalacturonan-I with arabinan side-chains (∼55-60%), as well as highly branched xyloglucans (∼30%) and cellulose. For both pseudocereals, 22% of total dietary fibre was soluble; a higher proportion than that found in wheat and maize (∼15%). The soluble fibre (SDF) was composed of glucose, galacturonic acid and arabinose; for amaranth, xylose was also a major constituent. Xyloglucans made up ∼40-60% of the SDF and arabinose-rich pectic polysaccharides represented ∼34-55%.

  15. Inhibition of intestinal disaccharidase activity by pentoses

    DEFF Research Database (Denmark)

    Halschou-Jensen, Kia

    -arabinose and D-xylose constituted the basis for the further investigations of L-arabinose. However, the use of higher dietary doses of sucrose would be unfeasible in terms of palatability in the human population. In paper 2, the purpose was to investigate if the positive effects of L-arabinose added to a sugar......The current health problems regarding the obesity epidemic, development of type 2 diabetes mellitus (T2D) and cardiovascular disease are a major challenge for healthcare systems worldwide.No simple or unique cure has been documented to prevent or treat this major health problem regarding T2D...... activity and change of diet, which corresponds to the treatment of insulin resistance, IGT and obesity. Secondly, a variety of medicine is used. Within nutrition, one of the research areas is preventive or therapeutic aims against development of T2D. A better glycaemic control is one preventive target...

  16. Chemical analysis of a polysaccharide of unripe (green) tomato (Lycopersicon esculentum).

    Science.gov (United States)

    Chandra, Krishnendu; Ghosh, Kaushik; Ojha, Arnab K; Islam, Syed S

    2009-11-02

    A polysaccharide (PS-I) isolated from the aqueous extract of the unripe (green) tomatoes (Lycopersicon esculentum) consists of D-galactose, D-methyl galacturonate, D-arabinose, L-arabinose, and L-rhamnose. Structural investigation of the polysaccharide was carried out using total acid hydrolysis, methylation analysis, periodate oxidation study, and NMR studies ((1)H, (13)C, DQF-COSY, TOCSY, NOESY, ROESY, HMQC, and HMBC). On the basis of above-mentioned experiments the structure of the repeating unit of the polysaccharide (PS-I) was established as: [structure: see text].

  17. Archaeal promoter architecture and mechanism of gene activation

    DEFF Research Database (Denmark)

    Peng, Nan; Ao, Xiang; Liang, Yun Xiang;

    2011-01-01

    Sulfolobus solfataricus and Sulfolobus islandicus contain several genes exhibiting D-arabinose-inducible expression and these systems are ideal for studying mechanisms of archaeal gene expression. At sequence level, only two highly conserved cis elements are present on the promoters: a regulatory...... element named ara box directing arabinose-inducible expression and the basal promoter element TATA, serving as the binding site for the TATA-binding protein. Strikingly, these promoters possess a modular structure that allows an essentially inactive basal promoter to be strongly activated. The invoked...

  18. Sustainable Synthesis of Chiral Tetrahydrofurans through the Selective Dehydration of Pentoses.

    Science.gov (United States)

    Foster, Robert W; Tame, Christopher J; Bučar, Dejan-Krešimir; Hailes, Helen C; Sheppard, Tom D

    2015-11-01

    L-Arabinose is an abundant resource available as a waste product of the sugar beet industry. Through use of a hydrazone-based strategy, L-arabinose was selectively dehydrated to form a chiral tetrahydrofuran on a multi-gram scale without the need for protecting groups. This approach was extended to other biomass-derived reducing sugars and the mechanism of the key cyclization investigated. This methodology was applied to the synthesis of a range of functionalized chiral tetrahydrofurans, as well as a formal synthesis of 3R-3-hydroxymuscarine.

  19. Screening of lactic acid bacteria for their potential as microbial cell factories for bioconversion of lignocellulosic feedstocks

    DEFF Research Database (Denmark)

    Boguta, Anna Monika; Bringel, Francoise; Martinussen, Jan

    2014-01-01

    of lactic acid bacteria was evaluated regarding their properties with respect to the conversion of lignocellulosic feedstocks. The strains were examined for their ability to utilize xylose and arabinose as well as their resistance towards common inhibitors from pretreated lignocellulosic biomass (furan...... derivatives, phenolic compounds, weak acids). Results: Among 296 tested Lactobacillus and Pediococcus strains, 3 L. pentosus, 1 P. acidilactici and 1 P. pentosaceus isolates were found to be both capable of utilizing xylose and arabinose and highly resistant to the key inhibitors from chemically pretreated...

  20. Enzymatic depolymerization of gum Tragacanth: Bifidogenic potential of low molecular weight oligosaccharides

    DEFF Research Database (Denmark)

    Ahmadi Gavlighi, Hassan; Michalak, Malwina; Meyer, Anne S.

    2013-01-01

    Gum tragacanth derived from the plant “goat’s horn” (Astragalus sp.) has a long history of use as a stabilizing, viscosity-enhancing agent in food emulsions. The gum contains pectinaceous arabinogalactans and fucose-substituted xylogalacturonans. In this work, gum tragacanth from Astragalus...... that these three fractions also varied with respect to composition and structural elements: HAG1 and HAG2 were enriched in arabinose, galactose, and galacturonic acid, but low in fucose and xylose; whereas HAG3 was high in (terminal) xylose, fucose and 1,4-bonded galacturonic acid, but low in arabinose...

  1. Investigation of Carbohydrate Compositions for Poplar Ⅰ-214 and Chinese Fir

    Institute of Scientific and Technical Information of China (English)

    HUANG Luohua; QIN Tefu; MAGARA Kengo

    2006-01-01

    The carbohydrate compositions of poplar Ⅰ-214 and Chinese fir were investigated by the methods of hydrolysis and HPLC.The result showed that the contents of glucose,xylose and arabinose in poplar Ⅰ-214 are higher than those in Chinese fir,while contents of rhamnose and mannose in poplar Ⅰ-214 are lower than those in Chinese fir.

  2. An upstream activation element exerting differential transcriptional activation on an archaeal promoter

    DEFF Research Database (Denmark)

    Peng, Nan; Xia, Qiu; Chen, Zhengjun

    2009-01-01

    Summary Microorganisms can utilize different sugars as energy and carbon sources and the genes involved in sugar metabolism often exhibit highly regulated expression. To study cis-acting elements controlling arabinose-responsive expression in archaea, the promoter of the Sulfolobus solfataricus a...

  3. Potential for using thermophilic anaerobic bacteria for bioethanol production from hemicellulose

    DEFF Research Database (Denmark)

    Sommer, P.; Georgieva, Tania I.; Ahring, Birgitte Kiær

    2004-01-01

    A limited number of bacteria, yeast and fungi can convert hemicellulose or its monomers (xylose, arabinose, mannose and galactose) into ethanol with a satisfactory yield and productivity. In the present study we tested a number of thermophilic enrichment cultures, and new isolates of thermophilic...

  4. Influence of food preservation parameters and associated microbiota on production rate, profile and stability of acylated homoserine lactones from food-derived Enterobacteriaceae

    DEFF Research Database (Denmark)

    Flodgaard, Lars; Christensen, Allan Beck; Molin, Søren;

    2003-01-01

    of carbon source (glucose,, sucrose, xylose, arabinose, mannose, mannitol and sorbitol), temperature (5 and 25 degreesC), salt concentration (0-7%), pH (6, 7 and 8) and co-existing lactic acid bacteria microflora on the AHL profile and production rate from Serratia proteamaculans strain B5a and Enterobacter...

  5. Induction, purification, and characterization of two extracellular alpha-L-arabinofuranosidases from Fusarium oxysporum

    DEFF Research Database (Denmark)

    Panagiotou, Gianni; Topakas, E.; Economou, L.;

    2003-01-01

    In the presence of L-arabinose as sole carbon source, Fusarium oxysporum produces two alpha-L-arabinofuranosidases (ABFs) named ABF1 and ABF2, with molecular masses of 200 and 180 kDa, respectively. The two F. oxysporum proteins have been purified to homogeneity. The purified enzymes are composed...

  6. Carbohydrate analysis of hemicelluloses by gas chromatography-mass spectrometry of acteylated methyl glycosides

    DEFF Research Database (Denmark)

    Sárossy, Zsuzsa; Plackett, David; Egsgaard, Helge

    2012-01-01

    A method based on gas chromatography–mass spectrometry analysis of acetylated methyl glycosides was developed in order to analyze monosaccharides obtained from various hemicelluloses. The derivatives of monosaccharide standards, arabinose, glucose, and xylose were studied in detail and 13C...

  7. Arabinase induction and carbon catabolite repression in Aspergillus niger and Aspergillus nidulans.

    NARCIS (Netherlands)

    Veen, van der P.

    1995-01-01

    The first aim of this thesis was to get a better understanding of the properties and the induction features of arabinan degrading enzymes and enzymes involved in the intracellular L-arabinose catabolic pathway in Aspergillus niger. The second aim was to understand the which role carbon catabolite re

  8. Recombinant cholera toxin B subunit in Escherichia coli: high-level secretion, purification, and characterization

    NARCIS (Netherlands)

    Slos, P.; Speck, D.; Accart, N.; Kolbe, H.V.; Schubnel, D.; Bouchon, B.; Bischoff, Rainer; Kieny, M.P.

    1994-01-01

    The gene coding for cholera toxin subunit B (CT-B) was fused to a modified ompA signal sequence and subsequently cloned into a high expression vector based on the regulatory signals of the arabinose operon of Salmonella typhimurium. Upon induction of gene expression in Escherichia coli, a product of

  9. Characterisation of complex xylo-oligosaccharides from xylan rich by-products

    NARCIS (Netherlands)

    Kabel, M.A.

    2002-01-01

    Hydrolysates obtained by hydrothermal treatment of four xylan rich by-products (wheat bran, brewery's spent grain, corn cobs and Eucalyptus wood) were characterised. Depending on the feedstock material studied, the xylan originally present differed in substitution with arabinose, 4- O -methylglucuro

  10. Synthesis of isofagomine-pyrrolidine hybrid sugars and analogues of (-)-steviamine and (+)-hyacinthacine C5 using 1,3-dipolar cycloaddition reactions.

    Science.gov (United States)

    Lahiri, Rima; Palanivel, Ashokkumar; Kulkarni, Sudhir A; Vankar, Yashwant D

    2014-11-21

    Highly regioselective 1,3-dipolar cycloadditions between d-arabinose-derived nitrones and d-mannitol-derived trans-olefins have been utilized to synthesize isofagomine-pyrrolidine hybrid sugars, hydroxymethylated analogues of (-)-steviamine and analogues of (+)-hyacinthacine C5. All of the new compounds were subsequently tested against several commercially available glycosidases, and some of them showed good and selective glycosidase inhibition.

  11. Environ: E00448 [KEGG MEDICUS

    Lifescience Database Archive (English)

    Full Text Available Arabinose [CPD:C00216], Pentose Sterculia scaphigera, Sterculia lychophora, Sterculia [TAX:66667] Malvaceae... (mallow family) Sterculia scaphigera, Sterculia lychophora mature seed (dried) Crude drugs [BR:br08305] Dicot plants: rosids Malvaceae (mallow family) E00448 Sterculia seed ...

  12. Structural insight into substrate binding and catalysis of a novel 2-keto-3-deoxy-D-arabinonate dehydratase illustrates common mechanistic features of the FAH superfamily

    NARCIS (Netherlands)

    Brouns, S.J.J.; Barends, T.R.M.; Worm, P.; Akerboom, J.; Turnbull, A.P.; Salmon, L.; Oost, van der J.

    2008-01-01

    The archaeon Sulfolobus solfataricus converts d-arabinose to 2-oxoglutarate by an enzyme set consisting of two dehydrogenases and two dehydratases. The third step of the pathway is catalyzed by a novel 2-keto-3-deoxy-D-arabinonate dehydratase (KdaD). In this study, the crystal structure of the enzym

  13. Characterization of Carbohydrate Active Enzymes Involved in Arabinogalactan Protein Metabolism

    DEFF Research Database (Denmark)

    Knoch, Eva

    accounting for up to 90% of the total mass. The glycan contains mostly galactose and arabinose, but glucoronic acid and other less-abundant sugars like rhamnose, xylose and fucose are also found. Although AGPs are important for normal plant growth and are found throughout the plant in virtually all organs...

  14. Aspergillus nidulans α-galactosidase of glycoside hydrolase family 36 catalyses the formation of α-galacto-oligosaccharides by transglycosylation

    DEFF Research Database (Denmark)

    Nakai, Hiroyuki; Baumann, Martin; Petersen, B. O.

    2010-01-01

    not transglycosylate monosaccharides without the 6-hydroxymethyl group, i.e. xylose, l-arabinose, l-fucose and l-rhamnose, or with axial 3-OH, i.e. gulose, allose, altrose and l-rhamnose. Structural modelling using Thermotoga maritima GH36 α-galactosidase as the template and superimposition of melibiose from...

  15. Otariodibacter oris gen. nov., sp. nov., a member of the family Pasteurellaceae isolated from the oral cavity of pinnipeds

    DEFF Research Database (Denmark)

    Hansen, Mie Johanne; Bertelsen, Mads Frost; Christensen, Henrik

    2012-01-01

    from existing genera of the Pasteurellaceae by the following tests: positive reactions for catalase, oxidase, Voges-Proskauer and indole; no X- or V-factor dependency; and acid production from L-arabinose (slow), L-fucose, maltose and trehalose, but not from dulcitol, D-mannitol, D-mannose or sucrose...

  16. Compositional analysis and rheological characterization of gum tragacanth exudates from six species of Iranian Astragalus

    DEFF Research Database (Denmark)

    Balaghi, Sima; Mohammadifar, Mohammad Amin; Zargaraan, Azizollaah

    2011-01-01

    -performance anion-exchange chromatography with pulsed amperometric detection suggested the occurrence of arabinose, xylose, glucose, galactose, fucose, rhamnose and galacturonic acid residues in the gum structure; however, the proportions of each sugar varied significantly among the gums from the different species...

  17. Stringent control of FLP recombinase in Escherichia coli.

    Science.gov (United States)

    Bowden, Steven D; Palani, Nagendra P; Libourel, Igor G L

    2017-02-01

    Site specific recombinases are invaluable tools in molecular biology, and are emerging as powerful recorders of cellular events in synthetic biology. We have developed a stringently controlled FLP recombinase system in Escherichia coli using an arabinose inducible promoter combined with a weak ribosome binding site.

  18. Enzyme kinetics and identification of the rate-limiting step of enzymatic arabinoxylan degradation

    DEFF Research Database (Denmark)

    Rasmussen, Louise Enggaard; Xu, Cheng; Sørensen, Jens

    2012-01-01

    This study investigated the kinetics of multi-enzymatic degradation of soluble wheat arabinoxylan by monitoring the release of xylose and arabinose during designed treatments with mono-component enzymes at different substrate concentrations. The results of different combinations of α-l-arabinofur...

  19. Isolation and structure elucidation of pectic polysaccharide from rose hip fruits (Rosa canina L.)

    NARCIS (Netherlands)

    Ognyanov, Manol; Remoroza, Connie; Schols, Henk A.; Georgiev, Yordan; Kratchanova, Maria; Kratchanov, Christo

    2016-01-01

    A pectic polysaccharide from rose hip (RH) fruits has been obtained by extraction with 1% aqueous citric acid. It was found that the polysaccharide fraction mainly consisted of galacturonic acid (45.5%) next to galactose (5.5%) and arabinose (4.7%). RH pectin is having a relatively high degree of

  20. Characterization of cell wall degrading enzymes from Chrysosporium lucknowense C1 and their use to degrade sugar beet pulp

    NARCIS (Netherlands)

    Kühnel, S.

    2011-01-01

    Key words: Pectin, arabinan, biorefinery, mode of action, branched arabinose oligomers, ferulic acid esterase, arabinohydrolase, pretreatment Sugar beet pulp is the cellulose and pectin-rich debris remaining after sugar extraction from sugar beets. In order to use sugar beet pulp for biorefinery pu

  1. Extracellular polysaccharide production by Thraustochytrid protists

    Digital Repository Service at National Institute of Oceanography (India)

    Jain, R.; Raghukumar, S.; Tharanathan, R.; Bhosle, N.B.

    of SO 4 2) . The component sugar analysis of both EPSs by gas chromatography showed that the molar ratio of arabinose, mannose, galactose, and glucose in the SC-1 EPS and CW1 EPS were 0.36:1.0:23.6:75.0 and 36:1.8:19.3:78.5, respec- tively (Figure 6...

  2. Monomer composition of polysaccharides of seed cell walls and the taxonomy of the Vochysiaceae.

    Science.gov (United States)

    Mayworm, M A; Buckeridge, M S; Salatino, A

    2000-11-01

    The distribution of polysaccharides from the seed cell walls of 57 samples of Vochysiaceae native to Brazil were studied, comprising 16 species distributed among the genera Callisthene, Qualea, Salvertia and Vochysia. The polysaccharides were extracted with hot water, then hydrolyzed with the resulting monomers analyzed by HPLC. All samples yielded arabinose, galactose, glucose. mannose and rhamnose, the relative amounts of each monomer, however, varying from one sample to another. Arabinose was always the predominant component, which implies that it might possibly be used as a marker of the Vochysiaceae. The quantitative distribution of monosaccharides was similar between the species of Qualea and Callisthene, characterized by the predominance of arabinose and mannose, and between the species of Salvertia and Vochysia, which contained higher amounts of arabinose and galactose. Such results are consistent with affinities inferred from floral morphology, wood anatomy and molecular data. Substantial intraspecific variation was observed for some species. UPGMA analysis based on the distribution of the monosaccharides reveals two main clusters, according to the links commented above. The resultant phenogram is not coherent with the current sectional classification of the Vochysiaceae, but the differences in the monosaccharides distribution between the two clusters are strongly supported by ANOVA.

  3. Chemical Synthesis of Hemicellulose Fragments

    DEFF Research Database (Denmark)

    Böhm, Maximilian Felix

    be preactivated again in a second step. Optimization of this strategy lead to a viable pathway towards a variety of protected xylan backbones. The use of protecting groups allows for the specific introduction of branching units to the backbone. Subsequently arabinose as well as glucuronic acid were attached...

  4. A single amino acid change (Y318F) in the L-arabitol dehydrogenase (LadA) from Aspergillus niger results in a significant increase in affinity for D-sorbitol

    NARCIS (Netherlands)

    Rutten, L.; Ribot, C.; Trejo-Aguilar, B.; Wosten, H.A.; De Vries, R.P.

    2009-01-01

    BACKGROUND: L-arabitol dehydrogenase (LAD) and xylitol dehydrogenase (XDH) are involved in the degradation of L-arabinose and D-xylose, which are among the most abundant monosaccharides on earth. Previous data demonstrated that LAD and XDH not only differ in the activity on their biological substrat

  5. NCBI nr-aa BLAST: CBRC-XTRO-01-0063 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-XTRO-01-0063 ref|YP_047119.1| putative arabinose exporter (MFS superfamily) [Acinetobacter... sp. ADP1] emb|CAG69297.1| putative sugar efflux transporter (MFS superfamily) [Acinetobacter sp. ADP1] YP_047119.1 8e-56 46% ...

  6. Characterization of carrot arabinogalactan proteins

    NARCIS (Netherlands)

    Immerzeel, P.

    2005-01-01

    Arabinogalactan proteins (AGPs) are highly glycosylated proteins. Besides galactose and arabinose the carbohydrate part of AGPs contains other neutral sugars and uronic acids. AGPs are widely distributed in the plant kingdom, probably occurring in all tissues of every plant. Yariv phenylglycoside is

  7. Regulated delayed expression of rfc enhances the immunogenicity and protective efficacy of a heterologous antigen delivered by live attenuated Salmonella enterica vaccines.

    Science.gov (United States)

    Kong, Qingke; Liu, Qing; Jansen, Angela M; Curtiss, Roy

    2010-08-23

    The Salmonella rfc gene encodes the O-antigen polymerase. We constructed three strains in which we replaced the native rfc promoter with the arabinose-dependent araC P(BAD) promoter so that rfc expression was dependent on exogenously supplied arabinose provided during in vitro growth. The three mutant strains were designed to synthesize different amounts of Rfc by altering the ribosome-binding sequence and start codon. We examined these strains for a number of in vitro characteristics compared to an isogenic Deltarfc mutant and the wild-type parent strain. One promoter-replacement mutation, DeltaP(rfc174), yielded an optimal profile, exhibiting wild-type characteristics when grown with arabinose, and Deltarfc characteristics when grown without arabinose. In addition, when administered orally, the DeltaP(rfc174) strain was completely attenuated in for virulence in mice. The DeltaP(rfc174) mutation was introduced into attenuated Salmonella vaccine strain chi9241 (DeltapabA DeltapabB DeltaasdA) followed by introduction of an Asd(+) balanced-lethal plasmid to designed for expression of the pneumococcal surface protein PspA. Mice immunized with either chi9241 or its DeltaP(rfc174) derivative expressing pspA were protected against S. pneumoniae challenge.

  8. Top Value Added Chemicals From Biomass. Volume 1 - Results of Screening for Potential Candidates From Sugars and Synthesis Gas

    Science.gov (United States)

    2004-08-01

    indeterminant Lactones, esters Antifreeze and deicers Fuel oxygenates Green solvents Phthalate polyesters Plasticizers Polyacrylates Polyacrylamides Phenol...UsesIntermediatesBiomass Feedstocks Sugars Glucose Fructose Xylose Arabinose Lactose Sucrose Starch Starch Cellulose Lignin Oil Protein Hemicellulose...molecular families, 2) could be produced from both lignocellulosics and starch , 3) were C1-C6 monomers, 4) were not aromatics derived from lignin, and 5

  9. N-Benzyl-3,5-dideoxy-3,5-imino-1,2-O-isopropylidene-β-l-lyxofuranose

    Directory of Open Access Journals (Sweden)

    David S. Edgeley

    2012-08-01

    Full Text Available X-ray crystallography confirmed the formation, structure and relative stereochemistry of the title compound, C15H19NO3, which contains a sterically congested four-membered azetidine ring system. The absolute configuration was determined by the use of l-arabinose as the starting material.

  10. Insecticidal Activity of Some Reducing Sugars Against the Sweet Potato Whitefly, Bemisia tabaci, Biotype B

    Science.gov (United States)

    The effects of 15 sugars on sweet potato whitefly (Bemisia tabaci) survival were determined using bioassays. Arabinose, mannose, ribose and xylose were strongly inhibitory to both nymphal and adult survival. When 10% mannose was added to the diet, 10.5%, 1.0% and 0% of nymphs developed to the 2nd, ...

  11. Genome-scale consequences of cofactor balancing in engineered pentose utilization pathways in Saccharomyces cerevisiae.

    Directory of Open Access Journals (Sweden)

    Amit Ghosh

    Full Text Available Biofuels derived from lignocellulosic biomass offer promising alternative renewable energy sources for transportation fuels. Significant effort has been made to engineer Saccharomyces cerevisiae to efficiently ferment pentose sugars such as D-xylose and L-arabinose into biofuels such as ethanol through heterologous expression of the fungal D-xylose and L-arabinose pathways. However, one of the major bottlenecks in these fungal pathways is that the cofactors are not balanced, which contributes to inefficient utilization of pentose sugars. We utilized a genome-scale model of S. cerevisiae to predict the maximal achievable growth rate for cofactor balanced and imbalanced D-xylose and L-arabinose utilization pathways. Dynamic flux balance analysis (DFBA was used to simulate batch fermentation of glucose, D-xylose, and L-arabinose. The dynamic models and experimental results are in good agreement for the wild type and for the engineered D-xylose utilization pathway. Cofactor balancing the engineered D-xylose and L-arabinose utilization pathways simulated an increase in ethanol batch production of 24.7% while simultaneously reducing the predicted substrate utilization time by 70%. Furthermore, the effects of cofactor balancing the engineered pentose utilization pathways were evaluated throughout the genome-scale metabolic network. This work not only provides new insights to the global network effects of cofactor balancing but also provides useful guidelines for engineering a recombinant yeast strain with cofactor balanced engineered pathways that efficiently co-utilizes pentose and hexose sugars for biofuels production. Experimental switching of cofactor usage in enzymes has been demonstrated, but is a time-consuming effort. Therefore, systems biology models that can predict the likely outcome of such strain engineering efforts are highly useful for motivating which efforts are likely to be worth the significant time investment.

  12. Decaprenylphosphoryl-β-D-ribose 2'-epimerase, the target of benzothiazinones and dinitrobenzamides, is an essential enzyme in Mycobacterium smegmatis.

    Directory of Open Access Journals (Sweden)

    Paul K Crellin

    Full Text Available BACKGROUND: The unique cell wall of bacteria of the suborder Corynebacterineae is essential for the growth and survival of significant human pathogens including Mycobacterium tuberculosis and Mycobacterium leprae. Drug resistance in mycobacteria is an increasingly common development, making identification of new antimicrobials a priority. Recent studies have revealed potent anti-mycobacterial compounds, the benzothiazinones and dinitrobenzamides, active against DprE1, a subunit of decaprenylphosphoribose 2' epimerase which forms decaprenylphosphoryl arabinose, the arabinose donor for mycobacterial cell wall biosynthesis. Despite the exploitation of Mycobacterium smegmatis in the identification of DprE1 as the target of these new antimicrobials and its use in the exploration of mechanisms of resistance, the essentiality of DprE1 in this species has never been examined. Indeed, direct experimental evidence of the essentiality of DprE1 has not been obtained in any species of mycobacterium. METHODOLOGY/PRINCIPAL FINDINGS: In this study we constructed a conditional gene knockout strain targeting the ortholog of dprE1 in M. smegmatis, MSMEG_6382. Disruption of the chromosomal copy of MSMEG_6382 was only possible in the presence of a plasmid-encoded copy of MSMEG_6382. Curing of this "rescue" plasmid from the bacterial population resulted in a cessation of growth, demonstrating gene essentiality. CONCLUSIONS/SIGNIFICANCE: This study provides the first direct experimental evidence for the essentiality of DprE1 in mycobacteria. The essentiality of DprE1 in M. smegmatis, combined with its conservation in all sequenced mycobacterial genomes, suggests that decaprenylphosphoryl arabinose synthesis is essential in all mycobacteria. Our findings indicate a lack of redundancy in decaprenylphosphoryl arabinose synthesis in M. smegmatis, despite the relatively large coding capacity of this species, and suggest that no alternative arabinose donors for cell wall

  13. Cryptococcus socialis sp. nov. and Cryptococcus consortionis sp. nov., Antarctic basidioblastomycetes

    Science.gov (United States)

    Vishniac, H. S.

    1985-01-01

    New yeasts from the Ross Desert (dry valley area) of Antarctica include Cryptococcus socialis sp. nov. and Cryptococcus consortionis sp. nov. Cryptococcus socialis MYSW A801-3aY1 (= ATCC 56685) requires no vitamins, assimilates L-arabinose, cellobiose, D-glucuronate, maltose, melezitose, raffinose, soluble starch, sucrose, and trehalose, and may be distinguished from all other basidioblastomycetes by the combination of amylose production, cellobiose assimilation, and failure to utilize nitrate, D-galactose, myo-inositol, and mannitol. Its guanine-plus-cytosine content is 56 mol%. Cryptococcus consortionis MYSW A801-3aY92 (= ATCC 56686) requires thiamine, assimilates L-arabinose, D-glucuronate, 2-ketogluconate, salicin, succinate, sucrose, trehalose, and D-xylose, and may be distinguished from all other basidioblastomycetes by the combination of amylose production and failure to utilize nitrate, cellobiose, D-galactose, myo-inositol, and mannitol. Its guanine-plus-cytosine content is 56 mol%.

  14. Molecular Weight and Monosaccharide Composition of Astragalus Polysaccharides

    Directory of Open Access Journals (Sweden)

    Pei-Pei Wang

    2008-10-01

    Full Text Available Two polysaccharides (APS-I and APS-II were isolated from the water extract of Radix Astragali and purified through ethanol precipitation, deproteination and by ion-exchange and gel-filtration chromatography. Their molecular weight was determined using high performance liquid chromatography and gel permeation chromatography (HPLC-GPC and their monosaccharide composition was analyzed by TLC and HPLC methods, using a refractive index detector (RID and an NH2 column. It was shown that APS-I consisted of arabinose and glucose and APS-II consisted of rhamnose, arabinose and glucose, in a molar ratio of 1:3.45 and 1:6.25:17.86, respectively. The molecular weights (Mw of APS-I and APS-II were 1,699,100 Da and 1,197,600 Da, respectively.

  15. Two-step enzymatic synthesis of guanine arabionside%两步酶法合成阿糖鸟苷

    Institute of Scientific and Technical Information of China (English)

    魏晓琨; 丁庆豹; 欧伶; 张鹭; 王昌禄

    2008-01-01

    The chemical synthesis of Guanine arabinoside (ara-G) is extremely complex, time-consuming, and seriously polluted. A two-step enzymatic synthesis process was developed to acquire ara-G easily. 2,6-Diaminopurine arabinoside (ara-DA) was first synthesized with purine nucleoside phosphorylase and pyrimidine nucleoside phos-phorylase produced by Enterobacter aerogenes DGW-07. The conversion yield of ara-DA could reach above 90% when the reaction liquid contained 30 mmol·L-1 uracil arabinoside as arabinose donor, 10 mmol·L-1 2,6-diaminopurine as arabinose acceptor in pH 7.0 20 mmol·L-1 phosphate buffer, and reacted at 60℃ for 48h. Then, ara-DA was effectively transformed into ara-G with adenylate deaminase produced by Aspergillus oryzae DAW-01. The total process had no complex separation and purification.

  16. Enzymatic synthesis of β-xylosyl-oligosaccharides by transxylosylation using two beta-xylosidases of glycoside hydrolase family 3 from Aspergillus nidulans FGSC A4

    DEFF Research Database (Denmark)

    Dilokpimol, Adiphol; Nakai, Hiroyuki; Gotfredsen, Charlotte Held

    2011-01-01

    alcohols as acceptors 18 different p-xylosyl-oligosaccharides were synthesised in 2-36% (BxlA) and 6-66% (BxlB) yields by transxylosylation. BxlA utilised the monosaccharides D-mannose, D-lyxose, D-talose, D-xylose, D-arabinose, L-fucose, D-glucose, D-galactose and D-fructose as acceptors, whereas Bxl......B used the same except for D-lyxose, D-arabinose and L-fucose. BxlB transxylosylated the disaccharides xylobiose, lactulose, sucrose, lactose and turanose in upto 35% yield, while BxlA gave inferior yields on these acceptors. The regioselectivity was acceptor dependent and primarily involved beta-1...

  17. European analytical column no. 39. Analytical chemistry and bioanalytical chemistrya yet unshaped social relationship

    DEFF Research Database (Denmark)

    Horvai, George; Worsfold, Paul; Karlberg, Bo

    2011-01-01

    as acceptors 18 different β-xylosyl-oligosaccharides were synthesised in 2–36% (BxlA) and 6–66% (BxlB) yields by transxylosylation. BxlA utilised the monosaccharides d-mannose, d-lyxose, d-talose, d-xylose, d-arabinose, l-fucose, d-glucose, d-galactose and d-fructose as acceptors, whereas BxlB used the same...... except for d-lyxose, d-arabinose and l-fucose. BxlB transxylosylated the disaccharides xylobiose, lactulose, sucrose, lactose and turanose in upto 35% yield, while BxlA gave inferior yields on these acceptors. The regioselectivity was acceptor dependent and primarily involved β-1,4 or 1,6 product linkage...

  18. Affecting osteoblastic responses with in vivo engineered potato pectin fragments

    DEFF Research Database (Denmark)

    Kokkonen, Hanna; Verhoef, Renè; Kauppinen, Kyösti

    2012-01-01

    Pectins, complex plant-derived polysaccharides, are novel candidates for biomaterial nanocoatings. Pectic rhamnogalacturonan-I regions (RG-I) can be enzymatically treated to so-called modified hairy regions (MHR). We surveyed the growth and differentiation of murine preosteoblastic MC3T3-E1 cells......; 6 mol % arabinose). Wild-type (modified hairy region from potato pectin (MHRP)_WT) fragment contained default amounts (58 mol % galactose; 13 mol % arabinose) of both sugars. Focal adhesions (FAs) indicating cellular attachment were quantified. Reverse transcriptase polymerase chain reaction (RT...... any of the pectin samples, of which the MHRP_WT seemed to function best. FA length was greater on MHRPTR_GAL than on other pectin samples, otherwise the mutants did not significantly deviate. RT-PCR results indicate that differences between the samples at the gene expression level might be even...

  19. Synthesis of S-linked oligoxylans

    DEFF Research Database (Denmark)

    Bonora, Beatrice

    a big challenge for thebiofuel industry. In particular, the enzymatic hydrolysis of lignocellulosicpolysaccharides is one of the limiting steps of the entire procedure and thereforethe enzymes involved in the degradation process must ideally be characterized andunderstood. This requires a detailed......-(1→4)-Dxylopyranosebackbone, which is branched by short carbohydrate chains. Thebranches include D-glucuronic acid and its methyl ether, L-arabinose and/or variousoligosaccharides like D-xylose, L-arabinose, D- or L-galactose and D-glucose. Thehydrolysis of these polysaccharides is catalyzed...... by several families of enzymes,collected under the name of Glycosyl Hydrolases (GHs). Among other methods,the use of enzyme inhibitors like thio-linked oligosaccharides has for a long timebeen a common tool to analyze and characterize these enzymes.In the present work the chemical synthesis of thio...

  20. Decomposition of wheat bran and ispaghula husk in the stomach and the small intestine of healthy men

    DEFF Research Database (Denmark)

    Andersen, J R; Bukhave, K; Højgaard, L;

    1988-01-01

    Decomposition of dietary fibers in the stomach and small bowel was studied in 13 healthy male volunteers. Liquid control meals were compared with test meals, which in addition contained a source of fiber (wheat bran or ispaghula husk) in random order. Aspirations were collected from the stomach...... for monosaccharides, either free or fiber-bound, by gas-liquid chromatography. Both types of fiber were hydrolyzed in the stomach, but not in the small bowel. Of ispaghula husk, 1-6% was hydrolyzed, as was 5-8% of wheat bran. Intestinal absorption of free arabinose was 85-93%, but excretion of arabinose in the urine...... was not greater than after control meals. For further evaluation of gastric hydrolysis six additional healthy male volunteers were studied by serial aspirations from the antral part of the stomach. Hydrolysis was instantaneous for both fibers, and was significantly more pronounced for wheat bran than...

  1. Isolation and Structural Analysis of an Acidic Polysaccharide from Astragalus membranaceus (Fisch.) Bunge

    Institute of Scientific and Technical Information of China (English)

    Shun-Chun Wang; Jun-Jie Shan; Zheng-Tao Wang; Zhi-Bi Hu

    2006-01-01

    A new water-soluble hetero-polysaccharide, APSlD3, was obtained from a hot-water extract of the roots of Astragalus membranaceus (Fisch.) Bunge by DEAE-Sepharose Fast Flow and Sephacryl S-300 chromatography.The molecular weight of APSlD3 was estimated to be 5.79 × 105 Da. Based on a sugar composition analysis,methylation analysis, partial hydrolysis and 13C nuclear magnetic resonance experimentation, it was concluded that the minimal repeat unit of APSlD3 was composed of one terminal arabinose, one 1,5-linked arabinose, one 1,3-linked rhamnose, one 1,3,4-linked rhamnose, five 1,4-linked methyl galacturonates and six 1,4-linked methyl glucuronates.

  2. [Separation, purification and structural characterization of acidic polysaccharide from Microcystic aeruginosa].

    Science.gov (United States)

    Wang, Xida; Wu, Guorong; Chen, Jingyao; Wang, Jian'an

    2003-12-01

    Acidic polysccharide was extracted by boiling water from Microcystic aeruginosa, isolated and purified by DEAE-52 gel column. IR, UV, HPLC and 13C-NMR were used for the structural analysis. Results showed that MAAP was a new acidic polysaccharide, it's molecular weigh was 2.0028 x 10(5), and it's chain was composed of a-glycoside linkage. The component of MAAP was identified as rhamnose, xylose, arabinose, galactose and galacturonic acid.

  3. High paracellular nutrient absorption in intact bats is associated with high paracellular permeability in perfused intestinal segments.

    Science.gov (United States)

    Brun, Antonio; Price, Edwin R; Gontero-Fourcade, Manuel N; Fernandez-Marinone, Guido; Cruz-Neto, Ariovaldo P; Karasov, William H; Caviedes-Vidal, Enrique

    2014-09-15

    Water-soluble nutrients are absorbed by the small intestine via transcellular and paracellular mechanisms. Based on a few previous studies, the capacity for paracellular nutrient absorption seems greater in flying mammals than in nonflying mammals, but there has been little investigation of the mechanisms driving this difference. Therefore, we studied three species each of bats (Artibeus lituratus, Sturnira lilium and Carollia perspicillata) and nonflying mammals (Akodon montensis, Mus musculus and Rattus norvegicus). Using standard pharmacokinetic techniques in intact animals, we confirmed the greater paracellular nutrient absorption in the fliers, comparing one species in each group. Then we conducted in situ intestinal perfusions on individuals of all species. In both approaches, we measured the absorption of 3OMD-glucose, a nonmetabolizable glucose analog absorbed both paracellularly and transcellularly, as well as L-arabinose, which has no mediated transport. Fractional absorption of L-arabinose was three times higher in the bat (S. lilium: 1.2±0.24) than in the rodent (A. montensis: 0.35±0.04), whereas fractional absorption of 3OMD-glucose was complete in both species (1.46±0.4 and 0.97±0.12, respectively). In agreement, bats exhibited two to 12 times higher l-arabinose clearance per square centimeter nominal surface area than rodents in intestinal perfusions. Using L-arabinose, we estimated that the contribution of the paracellular pathway to total glucose absorption was higher in all three bats (109-137%) than in the rodents (13-39%). These findings contribute to an emerging picture that reliance on the paracellular pathway for nutrient absorption is much greater in bats relative to nonflying mammals and that this difference is driven by differences in intestinal permeability to nutrient-sized molecules.

  4. Cloning, characterization, and engineering of fungal L-arabinitol dehydrogenases.

    Science.gov (United States)

    Kim, Byoungjin; Sullivan, Ryan P; Zhao, Huimin

    2010-07-01

    L-Arabinitol 4-dehydrogenase (LAD) catalyzes the conversion of L-arabinitol to L-xylulose with concomitant NAD(+) reduction in fungal L-arabinose catabolism. It is an important enzyme in the development of recombinant organisms that convert L: -arabinose to fuels and chemicals. Here, we report the cloning, characterization, and engineering of four fungal LADs from Penicillium chrysogenum, Pichia guilliermondii, Aspergillus niger, and Trichoderma longibrachiatum, respectively. The LAD from P. guilliermondii was inactive, while the other three LADs were NAD(+)-dependent and showed high catalytic activities, with P. chrysogenum LAD being the most active. T. longibrachiatum LAD was the most thermally stable and showed the maximum activity in the temperature range of 55-65 degrees C with the other LADs showed the maximum activity in the temperature range of 40-50 degrees C. These LADs were active from pH 7 to 11 with an optimal pH of 9.4. Site-directed mutagenesis was used to alter the cofactor specificity of these LADs. In a T. longibrachiatum LAD mutant, the cofactor preference toward NADP(+) was increased by 2.5 x 10(4)-fold, whereas the cofactor preference toward NADP(+) of the P. chrysogenum and A. niger LAD mutants was also drastically improved, albeit at the expense of significantly reduced catalytic efficiencies. The wild-type LADs and their mutants with altered cofactor specificity could be used to investigate the functionality of the fungal L-arabinose pathways in the development of recombinant organisms for efficient microbial L-arabinose utilization.

  5. Biochemical characterization and gene expression of two endo-arabinanases from Penicillium chrysogenum 31B.

    Science.gov (United States)

    Sakamoto, Tatsuji; Inui, Misako; Yasui, Kana; Tokuda, Sayaka; Akiyoshi, Mika; Kobori, Yohei; Nakaniwa, Tetsuko; Tada, Toshiji

    2012-02-01

    We previously described five arabinanolytic enzymes secreted by Penicillium chrysogenum 31B into the culture medium. Here, we describe a sixth such enzyme, termed AbnS1. Analysis of the reaction products of debranched arabinan revealed that AbnS1 cleaved the substrate in an endo manner. The optimum temperature of AbnS1 was 60°C, which was much higher than that of a cold-adapted endo-arabinanase (Abnc) produced by this strain. The abns1 cDNA gene encoding AbnS1 was isolated by in vitro cloning. The deduced amino acid sequence of AbnS1 had 70% identity with that of Abnc. Pfam analysis revealed a Glyco_hydro_43 domain at positions 28 to 318 of AbnS1. Semi-quantitative reverse transcription-polymerase chain reaction analysis indicated that the abns1 gene was constitutively expressed in P. chrysogenum 31B at a low level, although the expression was only slightly induced with arabinose and arabinan. In contrast, expression of the abnc gene encoding Abnc was strongly induced by arabinose, arabinitol, and arabinan. Using debranched arabinan as substrate, recombinant AbnS1 (rAbnS1) accumulated arabinobiose and arabinotriose as the major products. Recombinant Abnc (rAbnc) released mainly arabinotriose and lesser amounts of arabinose and arabinobiose than did rAbnS1. Branched arabinan was completely degraded to arabinose by the action of rAbnS1 or rAbnc in combination with α-L: -arabinofuranosidase.

  6. Elucidation of the biosynthesis of the di-C-glycosylflavone isoschaftoside, an allelopathic component from Desmodium spp. that inhibits Striga spp. development.

    Science.gov (United States)

    Hamilton, Mary L; Kuate, Serge P; Brazier-Hicks, Melissa; Caulfield, John C; Rose, Ruth; Edwards, Robert; Torto, Baldwyn; Pickett, John A; Hooper, Antony M

    2012-12-01

    Isoschaftoside, an allelopathic di-C-glycosylflavone from Desmodium spp. root exudates, is biosynthesised through sequential glucosylation and arabinosylation of 2-hydroxynaringenin with UDP-glucose and UDP-arabinose. Complete conversion to the flavone requires chemical dehydration implying a dehydratase enzyme has a role in vivo to complete the biosynthesis. The C-glucosyltransferase has been partially characterised and its activity demonstrated in highly purified fractions.

  7. Estruturação de cristais de gelo em soluções aquosas contendo solutos diversos Ice crystals structuring in water solutions containing different solutes

    Directory of Open Access Journals (Sweden)

    CLÉCIA SILVA CARNEIRO

    2000-02-01

    Full Text Available Existe uma grande demanda de conhecimentos na área de criopreservação de frutos tropicais com vistas a reduzir os danos celulares provocados por cristais de gelo durante o congelamento. O objetivo deste trabalho foi estudar a capacidade de estruturação de cristais de gelo. Soluções aquosas contendo arabinose, glicose, piridoxina, creatina, metionina, lisina e arginina, foram submetidas a congelamento lento em ar estático e as amostras resultantes examinadas por microscopia ótica sob luz polarizada. Os açúcares arabinose e glicose provocaram nos cristais de gelo estruturações que variaram de uma configuração hexagonal a uma arbórea, dentre outras. Vitaminas hidrossolúveis e compostos hidrofílicos ou hidrofóbicos favoreceram a formação de arranjamentos circulares filamentosos.There is a great demand for information about the cryopreservation of tropical fruits to reduce cell damage caused by ice crystals during freezing. The objective of this work was to study the structuring capacity of ice cristals. Water solutions having arabinose, glucose, pyridoxine, creatine, methionine, lysine and arginine were submitted to a slow freezing process and the resulting samples were examined under an optical microscope under polarized light. Sugars (arabinose and glucose caused a range of structures, from hexagonal to tree-like configurations, among others. Water soluble vitamins and hydrophilic or hydrophobic compounds favored the formation of needles arranged in a circular-type manner.

  8. A modified scheme for biotyping Gardnerella vaginalis.

    Science.gov (United States)

    Benito, R; Vazquez, J A; Berron, S; Fenoll, A; Saez-Neito, J A

    1986-06-01

    A scheme is proposed for biotyping Gardnerella vaginalis, based on detection of hippurate hydrolysis, beta-galactosidase (ONPG) and lipase, and fermentation of arabinose, galactose and xylose. Seventeen biotypes were found among 197 strains from asymptomatic women and patients with bacterial vaginosis (non-specific vaginitis). The distribution of biotypes was similar in both populations but some biotypes were found more frequently in patients. The proposed scheme is compared with those previously described.

  9. Biotypes of Gardnerella vaginalis isolated from urinary tract.

    Science.gov (United States)

    González-Pedraza Avilés, A; Ortíz-Zaragoza, M C; Inzunza-Montiel, A E; Ponce-Rosas, E R

    1996-01-01

    A modified scheme is proposed for biotyping Gardnerella vaginalis isolated from urinary tract of symptomatic and asymptomatic women based on detection of hippurate hydrolysis, beta-galactosidase (ONPG) and lipase, and fermentation of arabinose, galactose and xylose. Thirty biotypes were found among 73 strains. The distribution of biotypes was similar in both populations but the biotypes 1H, 5G and 7G were found more frequently in women without symptoms of urinary tract infection.

  10. Bypassing the Pentose Phosphate Pathway: Towards Modular Utilization of Xylose

    OpenAIRE

    Kulika Chomvong; Stefan Bauer; Daniel I Benjamin; Xin Li; Daniel K Nomura; Cate, Jamie H. D.

    2016-01-01

    The efficient use of hemicellulose in the plant cell wall is critical for the economic conversion of plant biomass to renewable fuels and chemicals. Previously, the yeast Saccharomyces cerevisiae has been engineered to convert the hemicellulose-derived pentose sugars xylose and arabinose to d-xylulose-5-phosphate for conversion via the pentose phosphate pathway (PPP). However, efficient pentose utilization requires PPP optimization and may interfere with its roles in NADPH and pentose product...

  11. Kinetics and Regulation Studies of the Production of β-Galactosidase from Kluyveromyces marxianus Grown on Different Substrates

    OpenAIRE

    2003-01-01

    Lactose-intolerance is manifested in 50 % of the world’s population. This can be remediated by removing lactose from the diet or converting it into glucose and galactose with β-galactosidase (EC 3.2.1.23). In this work, batch production of this enzyme in the presence of lactose, galactose, cellobiose, xylose, arabinose, sucrose and glucose was investigated using Kluyveromyces marxianus in shake flask culture studies. Substrate type and temperature were the independent variables that directly ...

  12. Polysaccharide enriched immunomodulatory fractions from Tinospora cordifolia (Willd) miers ax hook. f. & Thoms.

    Science.gov (United States)

    Sharma, Upendra; Bala, Manju; Saini, Rikki; Verma, Praveen Kumar; Kumar, Neeraj; Singh, Bikram; Munshi, Renuka Kulkarni; Bhalerao, Supriya

    2012-09-01

    Tinospora cordifolia is used in Ayurveda as "Rasayanas" to improve the immune system and the body resistance against infections. Polysaccharides are the main constituents which are considered to be responsible for immune enhancement. In this study, immunomodulatory activity of three polysaccharide enriched fractions was evaluated using the polymorphonuclear leukocyte function test. Sugar composition was determined by GC-MS analysis of the derivatised fractions. The active polysaccharide fractions mainly constitute glucose, fructose and arabinose as monomer units.

  13. A one-pot method for the selective conversion of hemicellulose from crop waste into C5 sugars and furfural by using solid acid catalysts.

    Science.gov (United States)

    Sahu, Ramakanta; Dhepe, Paresh Laxmikant

    2012-04-01

    We present a solid-acid catalyzed one-pot method for the selective conversion of solid hemicellulose without its separation from other lignocellulosic components, such as cellulose and lignin. The reactions were carried out in aqueous and biphasic media to yield xylose, arabinose, and furfural. To overcome the drawbacks posed by mineral acid methods in converting hemicelllulose, we used heterogeneous catalysts that work at neutral pH. In a batch reactor, these heterogeneous catalysts, such as solid acids (zeolites, clays, metal oxides etc.), resulted in >90 % conversion of hemicellulose. It has been shown that the selectivity for the products can be tuned by changing the reaction conditions, for example, a reaction carried out in water at 170 °C for 1 h with HBeta (Si/Al=19) and HUSY (Si/Al=15) catalysts gave yields of 62 and 56 % for xylose and arabinose, respectively. With increased reaction time (6 h) and in presence of only water, HUSY resulted in yields of 30 % xylose + arabinose and 18 % furfural. However, in a biphasic reaction system (water + p-xylene, 170 °C, 6 h) yields of 56 % furfural with 17 % xylose+arabinose could be achieved. It was shown that with the addition of organic solvent the furfural yield could be increased from 18 to 56 %. Under optimized reaction conditions, >90 % carbon balance was observed. The study revealed that catalysts were recyclable with a 20 % drop in activity for each subsequent run. It was observed that temperature, pressure, reaction time, substrate to catalyst ratio, solvent, and so forth had an effect on product formation. The catalysts were characterized by means of X-ray diffraction, temperature-programmed desorption of NH(3), inductively coupled plasma spectroscopy, elemental analysis, and solid-state NMR ((29)Si, (27)Al) spectroscopy techniques.

  14. The ability of Clostridium bifermentans strains to lactic acid biosynthesis in various environmental conditions

    OpenAIRE

    Leja, Katarzyna; Myszka, Kamila; Czaczyk, Katarzyna

    2013-01-01

    Clostridium bifermentans strains, isolated from a manure, were examinated for their ability to produce lactic acid from PY medium with glycerol under different pH conditions and when PY medium was supplemented with saccharides such as fructose, sorbitol, glucose, mannose, mannitol, maltose, xylose, raffinose, and arabinose. In the last test performed, the ability of investigated strains to produce lactic acid from mixed carbon source (glycerol plus saccharide) was checked. The strains of Cl. ...

  15. Positron emission tomography probe to monitor selected sugar metabolism in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Witte, Owen; Clark, Peter M.; Castillo, Blanca Graciela Flores; Jung, Michael E.; Evdokimov, Nikolai M.

    2017-03-14

    The invention disclosed herein discloses selected ribose isomers that are useful as PET probes (e.g. [18F]-2-fluoro-2-deoxy-arabinose). These PET probes are useful, for example, in methods designed to monitor physiological processes including ribose metabolism and/or to selectively observe certain tissue/organs in vivo. The invention disclosed herein further provides methods for making and using such probes.

  16. Increase in cellulose accumulation and improvement of saccharification by overexpression of arabinofuranosidase in rice.

    Directory of Open Access Journals (Sweden)

    Minako Sumiyoshi

    Full Text Available Cellulosic biomass is available for the production of biofuel, with saccharification of the cell wall being a key process. We investigated whether alteration of arabinoxylan, a major hemicellulose in monocots, causes an increase in saccharification efficiency. Arabinoxylans have β-1,4-D-xylopyranosyl backbones and 1,3- or 1,4-α-l-arabinofuranosyl residues linked to O-2 and/or O-3 of xylopyranosyl residues as side chains. Arabinose side chains interrupt the hydrogen bond between arabinoxylan and cellulose and carry an ester-linked feruloyl substituent. Arabinose side chains are the base point for diferuloyl cross-links and lignification. We analyzed rice plants overexpressing arabinofuranosidase (ARAF to study the role of arabinose residues in the cell wall and their effects on saccharification. Arabinose content in the cell wall of transgenic rice plants overexpressing individual ARAF full-length cDNA (OsARAF1-FOX and OsARAF3-FOX decreased 25% and 20% compared to the control and the amount of glucose increased by 28.2% and 34.2%, respectively. We studied modifications of cell wall polysaccharides at the cellular level by comparing histochemical cellulose staining patterns and immunolocalization patterns using antibodies raised against α-(1,5-linked l-Ara (LM6 and β-(1,4-linked d-Xyl (LM10 and LM11 residues. However, they showed no visible phenotype. Our results suggest that the balance between arabinoxylan and cellulose might maintain the cell wall network. Moreover, ARAF overexpression in rice effectively leads to an increase in cellulose accumulation and saccharification efficiency, which can be used to produce bioethanol.

  17. Preparation of 2-deoxyaldoses from aldose phenylhydrazones

    DEFF Research Database (Denmark)

    Jørgensen, Christel Thea; Pedersen, Christian

    1997-01-01

    Acetylation of D-mannose phenylhydrazone gives acetylated D-arabino-1-phenyl-azo-1-(E)-hexene. Subsequent reduction with sodium borohydride produces 2-deoxy-D-arabino-hexose phenylhydrazone which, on hydrolysis, gives 2-deoxy-D-arabino-hexose. By a similar procedure 2-deoxy-D-lyxo-hexose, 2,6-did......,6-dideoxy-L-arabino-hexose, and 2-deoxy-D-erythropentose can be prepared from D-galactose, L-rhamnose, and D-arabinose, respectively....

  18. ENTRAPMENT OF FLUORESCENT E. COLI CELLS IN ALGINATE GEL

    OpenAIRE

    V. IGNA; M. DRAGOMIRESCU; T. VINTILA; D. Vintila

    2009-01-01

    By this experiment we will demonstrate the possibility to obtain genetically modified microbial strains that can be used as markers in different studies. The trait transferred in this study is the fluorescence in UV light expressed by a gene isolated from jellyfish. This gene was insered into a plasmid carrying ampiciline resistance and in the operon for arabinose fermentation. The plasmid was called pGLO. E coli HB101 K-12, ampicillin resistant colonies has been obtained. The colonies on the...

  19. Arabinan Metabolism during Seed Development and Germination in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    Leonardo D. Gomez; Clare G. Steele-King; Louise Jones; Jonathan M. Foster; Supachai Vuttipongchaikij; Simon J. McQueen-Mason

    2009-01-01

    Arabinans are found in the pectic network of many cell walls, where, along with galactan, they are present as side chains of Rhamnogalacturonan I. Whilst arabinans have been reported to be abundant polymers in the cell walls of seeds from a range of plant species, their proposed role as a storage reserve has not been thoroughly investigated. In the cell walls of Arabidopsis seeds, arabinose accounts for approximately 40% of the monosaccharide composition of non-cellulosic polysaccharides of embryos. Arabinose levels decline to ~ 15% during seedling establishment, indicating that cell wall arabinans may be mobilized during germination. Immunolocalization of arabinan in embryos, seeds, and seedlings reveals that arabinans accumulate in developing and mature embryos, but disappear during germination and seedling establishment. Experiments using ~(14)C-arabinose show that it is readily incorporated and metabolized in growing seed-lings, indicating an active catabolic pathway for this sugar. We found that depleting arabinans in seeds using a fungal arabinanase causes delayed seedling growth, lending support to the hypothesis that these polymers may help fuel early seedling growth.

  20. Modulation of Candida albicans Biofilm by Different Carbon Sources.

    Science.gov (United States)

    Pemmaraju, Suma C; Pruthi, Parul A; Prasad, R; Pruthi, Vikas

    2016-06-01

    In the present investigation, the role of carbon sources (glucose, lactate, sucrose, and arabinose) on Candida albicans biofilm development and virulence factors was studied on polystyrene microtiter plates. Besides this, structural changes in cell wall component β-glucan in presence of different carbon sources have also been highlighted. Biofilm formation was analyzed by XTT (2,3-bis[2-Methoxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxanilide) reduction assay. Glucose-grown cells exhibited the highest metabolic activity during adhesion among all carbon sources tested (p roughness measurements by atomic force microscopy. Exposure to lactate induced hyphal structures with the highest proteinase activity while arabinose-grown cells formed pseudohyphal structures possessing the highest phospholipase activity. Structural changes in β-glucan characterized by Fourier transform infrared (FTIR) spectroscopy displayed characteristic band of β-glucan at 892 cm(-1) in all carbon sources tested. The β(1→6) to β(1→3) glucan ratio calculated as per the band area of the peak was less in lactate (1.15) as compared to glucose (1.73), sucrose (1.62), and arabinose (2.85). These results signify that carbon sources influence C. albicans biofilm development and modulate virulence factors and structural organization of cell wall component β-glucan.

  1. Substrate specificity and gene expression of two Penicillium chrysogenum α-L-arabinofuranosidases (AFQ1 and AFS1) belonging to glycoside hydrolase families 51 and 54.

    Science.gov (United States)

    Sakamoto, Tatsuji; Inui, Misako; Yasui, Kana; Hosokawa, Sachiko; Ihara, Hideshi

    2013-02-01

    We previously isolated two α-L-arabinofuranosidases (ABFs), termed AFQ1 and AFS1, from the culture filtrate of Penicillium chrysogenum 31B. afq1 and afs1 complementary DNAs encoding AFQ1 and AFS1 were isolated by in vitro cloning. The deduced amino acid sequences of AFQ1 and AFS1 are highly similar to those of Penicillium purpurogenum ABF 2 and ABF 1, respectively, which belong to glycoside hydrolase (GH) families 51 and 54, respectively. Pfam analysis revealed an "Alpha-L-AF_C" domain in AFQ1 and "ArabFuran-catal" and "AbfB" domains in AFS1. Semi-quantitative RT-PCR analysis indicated that the afq1 gene was constitutively expressed in P. chrysogenum 31B at a low level, although the expression was slightly induced with arabinose, arabinitol, arabinan, and arabinoxylan. In contrast, expression of the afs1 gene was strongly expressed by the above four carbohydrates and less strongly induced by galactan. Recombinant enzymes (rAFQ1 and rAFS1) expressed in Escherichia coli were active against both p-nitrophenyl α-L-arabinofuranoside and polysaccharides with different specificities. (1)H-NMR analysis revealed that rAFS1 degraded arabinofuranosyl side chains that were both singly and doubly linked to the backbones of arabinoxylan and L-arabinan. On the other hand, rAFQ1 preferentially released arabinose linked to C-3 of single-substituted xylose or arabinose residues in the two polysaccharides.

  2. Scanning the Escherichia coli chromosome by random transposon mutagenesis and multiple phenotypic screening.

    Science.gov (United States)

    Serina, Stefania; Nozza, Francesca; Nicastro, Giovanna; Faggioni, Federico; Mottl, Harald; Dehò, Gianni; Polissi, Alessandra

    2004-10-01

    Analysis of the complete DNA sequences of many microbial genomes available reveals a fair number of putative ORFs without an identified function. A systematic scan of the Escherichia coli chromosome was achieved by random transposition with a newly developed Tn5 minitransposon derivative carrying the arabinose-inducible araP(BAD) promoter oriented outward at one end (Tn5-araP(BAD)). The transposon insertion mutants obtained were assayed for conditional lethal phenotypes (arabinose dependence or sensitivity), for growth at two temperatures (37 and 15 degrees C) and in different media (rich and minimal medium). The Tn5-araP(BAD)-tagged genes were identified by sequencing the transposon insertion points. In this way we found a new essential gene cluster (yhbN-yhbG), produced conditional lethal (arabinose-dependent) mutations in already known essential genes (folD, frr, plsC, thiL, serS, thrS, and trpS) and provided a new phenotype (cold sensitivity) to other known genes (holD, ahpC, and tolA). Moreover, we identified eight putative ORFs (kch, ycaM, ycbQ, yddA, yddB, ydeK, ydeX, and yliF) that appear to be required in optimum growth conditions (rich medium at 37 degrees C) but not in the cold and in minimal medium.

  3. Isolation and characterization of yeasts capable of efficient utilization of hemicellulosic hydrolyzate as the carbon source.

    Science.gov (United States)

    Cassa-Barbosa, L A; Procópio, R E L; Matos, I T S R; Filho, S A

    2015-09-28

    Few yeasts have shown the potential to efficiently utilize hemicellulosic hydrolyzate as the carbon source. In this study, microorganisms isolated from the Manaus region in Amazonas, Brazil, were characterized based on their utilization of the pentoses, xylose, and arabinose. The yeasts that showed a potential to assimilate these sugars were selected for the better utilization of lignocellulosic biomass. Two hundred and thirty seven colonies of unicellular microorganisms grown on hemicellulosic hydrolyzate, xylose, arabinose, and yeast nitrogen base selective medium were analyzed. Of these, 231 colonies were subjected to sugar assimilation tests. One hundred and twenty five of these were shown to utilize hydrolyzed hemicellulose, xylose, or arabinose as the carbon source for growth. The colonies that showed the best growth (N = 57) were selected, and their internal transcribed spacer-5.8S rDNA was sequenced. The sequenced strains formed four distinct groups in the phylogenetic tree, and showed a high percentage of similarity with Meyerozyma caribbica, Meyerozyma guilliermondii, Trichosporon mycotoxinivorans, Trichosporon loubieri, Pichia kudriavzevii, Candida lignohabitans, and Candida ethanolica. The discovery of these xylose-fermenting yeasts could attract widespread interest, as these can be used in the cost-effective production of liquid fuel from lignocellulosic materials.

  4. Growth and ethanol fermentation ability on hexose and pentose sugars and glucose effect under various conditions in thermotolerant yeast Kluyveromyces marxianus

    Energy Technology Data Exchange (ETDEWEB)

    Rodrussamee, Nadchanok; Hirata, Katsushi; Suprayogi [Yamaguchi Univ., Ube (Japan). Graduate School of Medicine; Lertwattanasakul, Noppon; Kosaka, Tomoyuki [Yamaguchi Univ. (Japan). Faculty of Agriculture; Limtong, Savitree [Kasetsart Univ., Bangkok (Thailand). Faculty of Science; Yamada, Mamoru [Yamaguchi Univ., Ube (Japan). Graduate School of Medicine; Yamaguchi Univ. (Japan). Faculty of Agriculture

    2011-05-15

    Ethanol fermentation ability of the thermotolerant yeast Kluyveromyces marxianus, which is able to utilize various sugars including glucose, mannose, galactose, xylose, and arabinose, was examined under shaking and static conditions at high temperatures. The yeast was found to produce ethanol from all of these sugars except for arabinose under a shaking condition but only from hexose sugars under a static condition. Growth and sugar utilization rate under a static condition were slower than those under a shaking condition, but maximum ethanol yield was slightly higher. Even at 40 C, a level of ethanol production similar to that at 30 C was observed except for galactose under a static condition. Glucose repression on utilization of other sugars was observed, and it was more evident at elevated temperatures. Consistent results were obtained by the addition of 2-deoxyglucose. The glucose effect was further examined at a transcription level, and it was found that KmGAL1 for galactokinase and KmXYL1 for xylose reductase for galactose and xylose/arabinose utilization, respectively, were repressed by glucose at low and high temperatures, but KmHXK2 for hexokinase was not repressed. We discuss the possible mechanism of glucose repression and the potential for utilization of K. marxianus in high-temperature fermentation with mixed sugars containing glucose. (orig.)

  5. Demonstration of Chemical Equilibrium through Regeneration of Color in Blue Bottle Experiment

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    *R. Azmat

    2011-03-01

    Full Text Available Concept of equilibrium is very difficult to understand for under graduate students. This experiment has a good visual impact of demonstration of equilibrium and would be one way of stimulating awareness in chemistry. An alkaline solution of arabinose and methylene green in aqueous medium can be used to explain equilibrium visually through reaction of dissolved oxygen which was observed in “BLUE BOTTLE EXPERIMENT” that showed the shift of equilibrium by regeneration of color during shaking and upon standing equilibrium shift in the forward direction and color loss was observed. Shaking the solution raises the concentration of oxygen in the mixture and oxidizes the methylene green back to its blue form. When the dissolved oxygen has been consumed, the methylene green is slowly reduced back to its colorless form by the remaining arabinose and the cycle can be repeated many times by further shaking. The experiment was repeated with various concentrations of dye indicator, arabinose and sodium hydroxide concentration. It was observed that regeneration of color and colorloss is the best visual example of explanation of equilibrium.

  6. A sugar biomarker proxy for assessing terrestrial versus aquatic sedimentary input

    Science.gov (United States)

    Hepp, Johannes; Rabus, Max; Laforsch, Christian; Anhäuser, Tobias; Glaser, Bruno; Zech, Michael

    2016-04-01

    Lake sediments are valuable, often continuous and potentially high resolution archives for studying past climate changes. Thereby, one of the crucial questions is often whether the origin of the organic matter in lake sediments is allochthonous (terrestrial) or autochthonous (aquatic). Here we present patterns of neutral sugars of various plants and algae species to answer the question whether the deoxyhexoses (fucose, rhamnose) to pentoses (arabinose, xylose) ratio can serve as a proxy for aquatic versus terrestrial sedimentary lake input, respectively. Our sugar pattern results show that the fucose + rhamnose content plotted against arabinose and xylose in a ternary diagram can be used to distinguish between algae and other (namely aquatic plants, emergent plant, and terrestrial plants) sugar sources. This finding is confirmed by a compilation with sugar data from the literature. Mosses plot within the range of algae. Although the (fucose + rhamnose)/(arabinose + xylose) ratio yields some overlapping between algae and soil/litter samples, we recommend this ratio, particularly when applied within a multiproxy approach, as promising proxy for distinguishing between aquatic vs. terrestrial organic matter in sedimentary archives. Regarding the sugar concentrations of the investigated samples, emergent plants show the highest values as well as the highest variability. Mosses, aquatic plants and algae yield lower sugar concentrations comparable to those of terrestrial plants.

  7. Production and characterization of L-fucose dehydrogenase from newly isolated Acinetobacter sp. strain SA-134.

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    Ohshiro, Takashi; Morita, Noriyuki

    2014-01-01

    Microorganisms producing L-fucose dehydrogenase were screened from soil samples, and one of the isolated bacterial strains SA-134 was identified as Acinetobacter sp. by 16S rDNA gene analysis. The strain grew well utilizing L-fucose as a sole source of carbon, but all other monosaccharides tested such as D-glucose and D-arabinose did not support the growth of the strain in the absence of L-fucose. D-Arabinose inhibited the growth even in the culture medium containing L-fucose. Although the strain grew on some organic acids and amino acids such as citric acid and L-alanine as sole sources of carbon, the enzyme was produced only in the presence of L-fucose. The fucose dehydrogenase was purified to apparently homogeneity from the strain, and the native enzyme was a monomer of 25 kD. L-Fucose and D-arabinose were good substrates for the enzyme, but L-galactose was a poor substrate. The enzyme acted on both NAD(+) and NADP(+) in the similar manner.

  8. Claudin gene expression patterns do not associate with interspecific differences in paracellular nutrient absorption.

    Science.gov (United States)

    Price, Edwin R; Rott, Katherine H; Caviedes-Vidal, Enrique; Karasov, William H

    2016-01-01

    Bats exhibit higher paracellular absorption of glucose-sized molecules than non-flying mammals, a phenomenon that may be driven by higher permeability of the intestinal tight junctions. The various claudins, occludin, and other proteins making up the tight junctions are thought to determine their permeability properties. Here we show that absorption of the paracellular probe l-arabinose is higher in a bat (Eptesicus fuscus) than in a vole (Microtus pennsylvanicus) or a hedgehog (Atelerix albiventris). Furthermore, histological measurements demonstrated that hedgehogs have many more enterocytes in their intestines, suggesting that bats cannot have higher absorption of arabinose simply by having more tight junctions. We therefore investigated the mRNA levels of several claudins and occludin, because these proteins may affect permeability of tight junctions to macronutrients. To assess the expression levels of claudins per tight junction, we normalized the mRNA levels of the claudins to the constitutively expressed tight junction protein ZO-1, and combined these with measurements previously made in a bat and a rodent to determine if there were among-species differences. Although expression ratios of several genes varied among species, there was not a consistent difference between bats and non-flyers in the expression ratio of any particular gene. Protein expression patterns may differ from mRNA expression patterns, and might better explain differences among species in arabinose absorption.

  9. Extraction, characterization and in vitro antioxidant activity of polysaccharides from black soybean.

    Science.gov (United States)

    Liu, Jun; Wen, Xiao-yuan; Zhang, Xue-qing; Pu, Hui-min; Kan, Juan; Jin, Chang-hai

    2015-01-01

    Optimization of extraction conditions, preliminary characterization and in vitro antioxidant activity of polysaccharides from black soybean (BSPS) were investigated. The results of Box-Behnken design showed that the optimal extraction conditions for BSPS were as follows: ratio of water to material of 20 ml/g, extraction time of 6.4h and extraction temperature of 92 °C, with a corresponding yield of 2.56%. The crude BSPS were further fractionated on DEAE-52 and Sepharose CL-4B chromatography to afford three purified fractions (BSPS-1, BSPS-2 and BSPS-3). Chemical analysis showed that the three purified fractions were mainly composed of carbohydrate and uronic acid. In addition, BSPS-1 was composed of arabinose, rhamnose, galactose, glucose and mannose in the molar ratio of 1.79:1.00:2.59:26.54:1.01. BSPS-2 was composed of arabinose, rhamnose, xylose, galactose and mannose in the molar ratio of 8.10:4.80:9.15:13.38:1.00. BSPS-3 was composed of arabinose, rhamnose, galactose and mannose in the molar ratio of 16.80:3.60:33.66:1.00. The results of Fourier transform-infrared spectroscopy further confirmed the characteristic polysaccharide structures of the three purified fractions. Moreover, antioxidant assays showed crude BSPS and its purified fractions had potential superoxide anion and DPPH radical scavenging activities, and their antioxidant activity decreased in the order of crude BSPS > BSPS-3 > BSPS-2 > BSPS-1.

  10. A comparative study of the neutral and acidic polysaccharides from Allium macrostemon Bunge.

    Science.gov (United States)

    Zhang, Zhanjun; Wang, Fuhua; Wang, Mingchun; Ma, Liping; Ye, Hong; Zeng, Xiaoxiong

    2015-03-06

    Neutral and acidic polysaccharides, named AMP40N and AMP40S respectively, were isolated and purified from the dried bulbs of Allium macrostemon Bunge. Both of them showed a single and symmetrically sharp peak, indicating they were homogeneous polysaccharides. Molecular weights of AMP40N and AMP40S were determined to be 18.2 and 105.1 kDa, respectively. AMP40N was composed of arabinose and glucose, while AMP40S was composed of rhamnose, arabinose, glucose and galactose and a certain amount of uronic acid. FT-IR, periodic acid oxidation, Smith degradation, methylation and GC-MS analysis revealed that non-reducing terminal and →2,6)-Glc-(1→ existed in AMP40N and AMP40S. The glycosidic linkage of arabinose in AMP40N was →2)-Ara-(1→, whereas it was Ara-(1→ in AMP40S. AMP40S had (1→2)-linked l-rhamnose residue. Both AMP40N and AMP40S exhibited strong anti-tumor potential against human gastric carcinoma cells BGC-823, in particular, AMP40S presented significantly higher inhibitory rate of 85.94% than AMP40N of 52.63%.

  11. Continuous Ethanol Fermentation of Pretreated Lignocellulosic Biomasses, Waste Biomasses, Molasses and Syrup Using the Anaerobic, Thermophilic Bacterium Thermoanaerobacter italicus Pentocrobe 411.

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    Rasmus Lund Andersen

    Full Text Available Lignocellosic ethanol production is now at a stage where commercial or semi-commercial plants are coming online and, provided cost effective production can be achieved, lignocellulosic ethanol will become an important part of the world bio economy. However, challenges are still to be overcome throughout the process and particularly for the fermentation of the complex sugar mixtures resulting from the hydrolysis of hemicellulose. Here we describe the continuous fermentation of glucose, xylose and arabinose from non-detoxified pretreated wheat straw, birch, corn cob, sugar cane bagasse, cardboard, mixed bio waste, oil palm empty fruit bunch and frond, sugar cane syrup and sugar cane molasses using the anaerobic, thermophilic bacterium Thermoanaerobacter Pentocrobe 411. All fermentations resulted in close to maximum theoretical ethanol yields of 0.47-0.49 g/g (based on glucose, xylose, and arabinose, volumetric ethanol productivities of 1.2-2.7 g/L/h and a total sugar conversion of 90-99% including glucose, xylose and arabinose. The results solidify the potential of Thermoanaerobacter strains as candidates for lignocellulose bioconversion.

  12. Continuous Ethanol Fermentation of Pretreated Lignocellulosic Biomasses, Waste Biomasses, Molasses and Syrup Using the Anaerobic, Thermophilic Bacterium Thermoanaerobacter italicus Pentocrobe 411.

    Science.gov (United States)

    Andersen, Rasmus Lund; Jensen, Karen Møller; Mikkelsen, Marie Just

    2015-01-01

    Lignocellosic ethanol production is now at a stage where commercial or semi-commercial plants are coming online and, provided cost effective production can be achieved, lignocellulosic ethanol will become an important part of the world bio economy. However, challenges are still to be overcome throughout the process and particularly for the fermentation of the complex sugar mixtures resulting from the hydrolysis of hemicellulose. Here we describe the continuous fermentation of glucose, xylose and arabinose from non-detoxified pretreated wheat straw, birch, corn cob, sugar cane bagasse, cardboard, mixed bio waste, oil palm empty fruit bunch and frond, sugar cane syrup and sugar cane molasses using the anaerobic, thermophilic bacterium Thermoanaerobacter Pentocrobe 411. All fermentations resulted in close to maximum theoretical ethanol yields of 0.47-0.49 g/g (based on glucose, xylose, and arabinose), volumetric ethanol productivities of 1.2-2.7 g/L/h and a total sugar conversion of 90-99% including glucose, xylose and arabinose. The results solidify the potential of Thermoanaerobacter strains as candidates for lignocellulose bioconversion.

  13. The biosynthesis and wall-binding of hemicelluloses in cellulose-deficient maize cells:An example of metabolic plasticity

    Institute of Scientific and Technical Information of China (English)

    Mara de Castro; Janice G Miller; Jose Luis Acebes; Antonio Encina; Penelope Garca-Angulo; Stephen C Fry

    2015-01-01

    Cell-suspension cultures (Zea mays L., Black Mexican sweet corn) habituated to 2,6-dichlorobenzonitrile (DCB) survive with reduced cellulose owing to hemicellulose network modification. We aimed to define the hemicellulose metabolism modifications in DCB-habituated maize cells showing a mild reduction in cellulose at different stages in the culture cycle. Using pulse-chase radiolabeling, we fed habituated and non-habituated cultures with [3H]arabinose, and traced the distribution of 3H-pentose residues between xylans, xyloglucans and other polymers in several cellular compartments for 5 h. Habituated cells were slower taking up exogenous [3H]arabinose. Tritium was incorporated into polysaccharide-bound arabinose and xylose residues, but habituated cells diverted a higher proportion of their new [3H] xylose residues into (hetero) xylans at the expense of xyloglucan synthesis. During logarithmic growth, habituated cells showed slower vesicular trafficking of polymers, especially xylans. Moreover, habituated cells showed a decrease in the strong wall-binding of all pentose-containing polysaccharides studied; correspondingly, especially in log-phase cultures, habituation increased the proportion of 3H-hemicelluloses ([3H]xylans and [3H]xyloglucan) sloughed into the medium. These findings could be related to the cell walls’ cellulose-deficiency, and consequent reduction in binding sites for hemicelluloses; the data could also reflect the habituated cells’ reduced capacity to integrate arabinox-ylans by extra-protoplasmic phenolic cross-linking, as well as xyloglucans, during wall assembly.

  14. Salmonella typhi: lisotipia VI e biotipificação em amostras oriundas de algumas regiões do Brasil Salmonella typhi: lysotype VI and biotyping in sample from some regions of Brazil

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    Ernesto Hofer

    1984-03-01

    Full Text Available Fez-se uma análise da distribuicão da frequência dos lisotipos VI e dos tipos fermentativos segundo o esquema de Kristensen, em 1.150 amostras de Salmonella typhi, isoladas de diferentes regiões do Brasil (Pará, Pernambuco, Bahia, Minas Gerais, Rio de Janeiro, São Paulo e Rio Grande do Sul. No computo geral, observou-se a prevalência dos lisotipos A (38,1%; Ela (18,9%; amostras VI negativas (16,6%; D6 (8,7% I + IV (4,6%; T (2,3% e C1 (2,1% e a ocorrência de alguns tipos fágicos característicos para determinadas áreas (B3, C4 e 40 na Bahia; E1b, F2, G1 e L1 em São Paulo; E4 e 28 no Rio de Janeiro. Quanto a classificacão bioquímica, 55,2% das amostras caracterizaram-se no biotipo II (xilose e arabinose negativas, 44,2% no tipo fermentativo I (xilose positiva e arabinose negativas e 0,52% no tipo III (xilose e arabinose positivas, respectivamente.The frequency of Vi-phage types and fermentative types according to Kristensen's scheme was studied among 1,150 strains of Salmonella typhi isolated from different areas in Brazil (states of Pará, Pernambuco, Bahia, Minas Gerais, Rio de Janeiro, São Paulo and Rio Grande do Sul. The most prevalent phage types encountered in this study were: A (38.1%; Ela (18.9%, D6 (8.7%, T (2.3% and C1 (2.1%, including categories of untypable strains (group I + IV-4.6%, and Vi negative (16.6%. There was,however, some types characteristics of particular areas (B3, C4, 40 from Bahia; Elb, F2,G1, L1 from São Paulo; E4 and 28 from Rio de Janeiro. In respect to the biochemical classification, 55.2% of the strains were classified as a biotype II (xylose and arabinose negative, 44,2% as of type I (xylose positive and negative0 and 0.52% as a type III (xylose and arabinose positive, respectively.

  15. Lipid production in batch and fed-batch cultures of Rhodosporidium toruloides from 5 and 6 carbon carbohydrates

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    Wiebe Marilyn G

    2012-05-01

    Full Text Available Abstract Background Microbial lipids are a potential source of bio- or renewable diesel and the red yeast Rhodosporidium toruloides is interesting not only because it can accumulate over 50% of its dry biomass as lipid, but also because it utilises both five and six carbon carbohydrates, which are present in plant biomass hydrolysates. Methods R. toruloides was grown in batch and fed-batch cultures in 0.5 L bioreactors at pH 4 in chemically defined, nitrogen restricted (C/N 40 to 100 media containing glucose, xylose, arabinose, or all three carbohydrates as carbon source. Lipid was extracted from the biomass using chloroform-methanol, measured gravimetrically and analysed by GC. Results Lipid production was most efficient with glucose (up to 25 g lipid L−1, 48 to 75% lipid in the biomass, at up to 0.21 g lipid L−1 h−1 as the sole carbon source, but high lipid concentrations were also produced from xylose (36 to 45% lipid in biomass. Lipid production was low (15–19% lipid in biomass with arabinose as sole carbon source and was lower than expected (30% lipid in biomass when glucose, xylose and arabinose were provided simultaneously. The presence of arabinose and/or xylose in the medium increased the proportion of palmitic and linoleic acid and reduced the proportion of oleic acid in the fatty acids, compared to glucose-grown cells. High cell densities were obtained in both batch (37 g L−1, with 49% lipid in the biomass and fed-batch (35 to 47 g L−1, with 50 to 75% lipid in the biomass cultures. The highest proportion of lipid in the biomass was observed in cultures given nitrogen during the batch phase but none with the feed. However, carbohydrate consumption was incomplete when the feed did not contain nitrogen and the highest total lipid and best substrate consumption were observed in cultures which received a constant low nitrogen supply. Conclusions Lipid production in R. toruloides was lower from arabinose and mixed

  16. The chemoenzymatic synthesis of clofarabine and related 2′-deoxyfluoroarabinosyl nucleosides: the electronic and stereochemical factors determining substrate recognition by E. coli nucleoside phosphorylases

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    Ilja V. Fateev

    2014-07-01

    Full Text Available Two approaches to the synthesis of 2-chloro-9-(2-deoxy-2-fluoro-β-D-arabinofuranosyladenine (1, clofarabine were studied. The first approach consists in the chemical synthesis of 2-deoxy-2-fluoro-α-D-arabinofuranose-1-phosphate (12a, 2FAra-1P via three step conversion of 1,3,5-tri-O-benzoyl-2-deoxy-2-fluoro-α-D-arabinofuranose (9 into the phosphate 12a without isolation of intermediary products. Condensation of 12a with 2-chloroadenine catalyzed by the recombinant E. coli purine nucleoside phosphorylase (PNP resulted in the formation of clofarabine in 67% yield. The reaction was also studied with a number of purine bases (2-aminoadenine and hypoxanthine, their analogues (5-aza-7-deazaguanine and 8-aza-7-deazahypoxanthine and thymine. The results were compared with those of a similar reaction with α-D-arabinofuranose-1-phosphate (13a, Ara-1P. Differences of the reactivity of various substrates were analyzed by ab initio calculations in terms of the electronic structure (natural purines vs analogues and stereochemical features (2FAra-1P vs Ara-1P of the studied compounds to determine the substrate recognition by E. coli nucleoside phosphorylases. The second approach starts with the cascade one-pot enzymatic transformation of 2-deoxy-2-fluoro-D-arabinose into the phosphate 12a, followed by its condensation with 2-chloroadenine thereby affording clofarabine in ca. 48% yield in 24 h. The following recombinant E. coli enzymes catalyze the sequential conversion of 2-deoxy-2-fluoro-D-arabinose into the phosphate 12a: ribokinase (2-deoxy-2-fluoro-D-arabinofuranose-5-phosphate, phosphopentomutase (PPN; no 1,6-diphosphates of D-hexoses as co-factors required (12a, and finally PNP. The substrate activities of D-arabinose, D-ribose and D-xylose in the similar cascade syntheses of the relevant 2-chloroadenine nucleosides were studied and compared with the activities of 2-deoxy-2-fluoro-D-arabinose. As expected, D-ribose exhibited the best substrate

  17. Response of the grass-cutting ant Atta capiguara Gonçalves, 1944 (Hymenoptera: Formicidae to sugars and artificial sweeteners Resposta da saúva Atta capiguara Gonçalves, 1944 (Hymenoptera: Formicidae a açúcares e edulcorantes artificiais

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    Maria Aparecida Castellani Boaretto

    2003-01-01

    Full Text Available Using of toxic baits made of dehydrated citric pulp to control grass-cutting ants can lead to unsatisfactory results because of the low attractiveness of the substrate to worker ants. This work aimed to identify attractive substances, with potential for incorporation in a matrix of granulated baits for grass-cutting ants, among several kinds of sugars and substances used in artificial sweeteners. Experiments were carried out in mature nests of Atta capiguara (Hym.: Formicidae set in pasture. Studied substances were sucrose, fructose, soluble starch, raffinose, maltose, lactose, sorbose, cellobiose, arabinose, xylose, glucose, galactose, rhamnose, arabinose, melezitose, saccharine and cyclamate (at 5.0% w/v. Later, on maltose, xylose, sucrose, fructose and glucose solutions were included at 5.0%, 7.5%, 10.0% and 20.0% w/v, respectively. Cellulose rectangles were used as vehicle and number of rectangles carried into the colonies was evaluated. Carrying rates were very low with maximum means of 9.6% for lactose and 6.0% for arabinose and cyclamate, at the 5.0% concentration. No differences (P > 0.05 were observed relatively to the control (distilled water. No effects were detected for solution, concentration and for the interaction of these factors. Sugars and artificial sweeteners studied were not attractive to Atta capiguara workers, turning their inclusion as attractants in toxic ant baits not viable.O uso de iscas tóxicas, formuladas à base de polpa cítrica desidratada, para o controle de formigas cortadeiras de gramíneas pode levar a resultados insatisfatórios devido à baixa atratividade do substrato às operárias. Este trabalho foi realizado com o objetivo de identificar substâncias atrativas e com potencial para incorporação em matrizes de iscas granuladas para formigas cortadeiras de gramíneas, dentre diversos tipos de açúcares e edulcorantes artificiais. Os experimentos foram realizados em ninhos adultos de Atta capiguara Gon

  18. Leaf biomechanical properties in Arabidopsis thaliana polysaccharide mutants affect drought survival.

    Science.gov (United States)

    Balsamo, Ronald; Boak, Merewyn; Nagle, Kayla; Peethambaran, Bela; Layton, Bradley

    2015-11-26

    Individual sugars are the building blocks of cell wall polysaccharides, which in turn comprise a plant׳s overall architectural structure. But which sugars play the most prominent role in maintaining a plant׳s mechanical stability during large cellular deformations induced by drought? We investigated the individual contributions of several genes that are involved in the synthesis of monosaccharides which are important for cell wall structure. We then measured drought tolerance and mechanical integrity during simulated drought in Arabidopsis thaliana. To assess mechanical properties, we designed a small-scale tensile tester for measuring failure strain, ultimate tensile stress, work to failure, toughness, and elastic modulus of 6-week-old leaves in both hydrated and drought-simulated states. Col-0 mutants used in this study include those deficient in lignin, cellulose, components of hemicellulose such as xylose and fucose, the pectic components arabinose and rhamnose, as well as mutants with enhanced arabinose and total pectin content. We found that drought tolerance is correlated to the mechanical and architectural stability of leaves as they experience dehydration. Of the mutants, S096418 with mutations for reduced xylose and galactose was the least drought tolerant, while the arabinose-altered CS8578 mutants were the least affected by water loss. There were also notable correlations between drought tolerance and mechanical properties in the diminished rhamnose mutant, CS8575 and the dehydrogenase-disrupted S120106. Our findings suggest that components of hemicellulose and pectins affect leaf biomechanical properties and may play an important role in the ability of this model system to survive drought.

  19. Purification and characterization of xylitol dehydrogenase with l-arabitol dehydrogenase activity from the newly isolated pentose-fermenting yeast Meyerozyma caribbica 5XY2.

    Science.gov (United States)

    Sukpipat, Wiphat; Komeda, Hidenobu; Prasertsan, Poonsuk; Asano, Yasuhisa

    2017-01-01

    Meyerozyma caribbica strain 5XY2, which was isolated from an alcohol fermentation starter in Thailand, was found to catabolize l-arabinose as well as d-glucose and d-xylose. The highest production amounts of ethanol from d-glucose, xylitol from d-xylose, and l-arabitol from l-arabinose were 0.45 g/g d-glucose, 0.60 g/g d-xylose, and 0.61 g/g l-arabinose with 21.7 g/L ethanol, 20.2 g/L xylitol, and 30.3 g/l l-arabitol, respectively. The enzyme with l-arabitol dehydrogenase (LAD) activity was purified from the strain and found to exhibit broad specificity to polyols, such as xylitol, d-sorbitol, ribitol, and l-arabitol. Xylitol was the preferred substrate with Km=16.1 mM and kcat/Km=67.0 min(-1)mM(-1), while l-arabitol was also a substrate for the enzyme with Km=31.1 mM and kcat/Km=6.5 min(-1) mM(-1). Therefore, this enzyme from M. caribbica was named xylitol dehydrogenase (McXDH). McXDH had an optimum temperature and pH at 40°C and 9.5, respectively. The McXDH gene included a coding sequence of 1086 bp encoding a putative 362 amino acid protein of 39 kDa with an apparent homopentamer structure. Native McXDH and recombinant McXDH exhibited relative activities toward l-arabitol of approximately 20% that toward xylitol, suggesting the applicability of this enzyme with the functions of XDH and LAD to the development of pentose-fermenting Saccharomyces cerevisiae.

  20. Purification, characterization, and mode of action of endoxylanases 1 and 2 from Fibrobacter succinogenes S85.

    Science.gov (United States)

    Matte, A; Forsberg, C W

    1992-01-01

    Two different endoxylanases (1,4-beta-D-xylan xylanohydrolases, EC 3.2.1.8), designated 1 and 2, have been purified by column chromatography to apparent homogeneity from the nonsedimentable extracellular culture fluid of the strictly anaerobic, ruminal bacterium Fibrobacter succinogenes S85 grown on crystalline cellulose. Endoxylanases 1 and 2 were shown to be basic proteins of 53.7 and 66.0 kDa, respectively, with different pH and temperature optima, as well as different substrate hydrolysis characteristics. The Km and Vmax values with water-soluble oat spelts xylan as substrate were 2.6 mg ml-1 and 33.6 mumol min-1 mg-1 for endoxylanase 1 and 1.3 mg ml-1 and 118 mumol min-1 mg-1 for endoxylanase 2. Endoxylanase 1, but not endoxylanase 2, released arabinose from water-soluble oat spelts xylan and rye flour arabinoxylan, but not from arabinan, arabinogalactan, or aryl-alpha-L-arabinofuranosides. With an extended hydrolysis time, endoxylanase 1 released 62.5 and 50% of the available arabinose from water-soluble oat spelts xylan and rye flour arabinoxylan, respectively. Endoxylanase 1 released arabinose directly from the xylan backbone, and this preceded hydrolysis of the xylan to xylooligosaccharides. Endoxylanase 2 showed significant activity against carboxymethyl cellulose but was unable to substantially hydrolyze acid-swollen cellulose. Both enzymes were endo-acting, as revealed by their hydrolysis product profiles on water-soluble xylan and xylooligosaccharides. Because of their unique hydrolytic properties, endoxylanases 1 and 2 appear to have strategic roles in plant cell wall digestion by F. succinogenes in vivo. Images PMID:1539970

  1. Biotechnology by Design: An Introductory Level, Project-Based, Synthetic Biology Laboratory Program for Undergraduate Students.

    Science.gov (United States)

    Beach, Dale L; Alvarez, Consuelo J

    2015-12-01

    Synthetic biology offers an ideal opportunity to promote undergraduate laboratory courses with research-style projects, immersing students in an inquiry-based program that enhances the experience of the scientific process. We designed a semester-long, project-based laboratory curriculum using synthetic biology principles to develop a novel sensory device. Students develop subject matter knowledge of molecular genetics and practical skills relevant to molecular biology, recombinant DNA techniques, and information literacy. During the spring semesters of 2014 and 2015, the Synthetic Biology Laboratory Project was delivered to sophomore genetics courses. Using a cloning strategy based on standardized BioBrick genetic "parts," students construct a "reporter plasmid" expressing a reporter gene (GFP) controlled by a hybrid promoter regulated by the lac-repressor protein (lacI). In combination with a "sensor plasmid," the production of the reporter phenotype is inhibited in the presence of a target environmental agent, arabinose. When arabinose is absent, constitutive GFP expression makes cells glow green. But the presence of arabinose activates a second promoter (pBAD) to produce a lac-repressor protein that will inhibit GFP production. Student learning was assessed relative to five learning objectives, using a student survey administered at the beginning (pre-survey) and end (post-survey) of the course, and an additional 15 open-ended questions from five graded Progress Report assignments collected throughout the course. Students demonstrated significant learning gains (p Biology Laboratory Project enhanced their understanding of molecular genetics. The laboratory project is highly adaptable for both introductory and advanced courses.

  2. Global microarray analysis of carbohydrate use in alkaliphilic hemicellulolytic bacterium Bacillus sp. N16-5.

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    Yajian Song

    Full Text Available The alkaliphilic hemicellulolytic bacterium Bacillus sp. N16-5 has a broad substrate spectrum and exhibits the capacity to utilize complex carbohydrates such as galactomannan, xylan, and pectin. In the monosaccharide mixture, sequential utilization by Bacillus sp. N16-5 was observed. Glucose appeared to be its preferential monosaccharide, followed by fructose, mannose, arabinose, xylose, and galactose. Global transcription profiles of the strain were determined separately for growth on six monosaccharides (glucose, fructose, mannose, galactose, arabinose, and xylose and four polysaccharides (galactomannan, xylan, pectin, and sodium carboxymethylcellulose using one-color microarrays. Numerous genes potentially related to polysaccharide degradation, sugar transport, and monosaccharide metabolism were found to respond to a specific substrate. Putative gene clusters for different carbohydrates were identified according to transcriptional patterns and genome annotation. Identification and analysis of these gene clusters contributed to pathway reconstruction for carbohydrate utilization in Bacillus sp. N16-5. Several genes encoding putative sugar transporters were highly expressed during growth on specific sugars, suggesting their functional roles. Two phosphoenolpyruvate-dependent phosphotransferase systems were identified as candidate transporters for mannose and fructose, and a major facilitator superfamily transporter was identified as a candidate transporter for arabinose and xylose. Five carbohydrate uptake transporter 1 family ATP-binding cassette transporters were predicted to participate in the uptake of hemicellulose and pectin degradation products. Collectively, microarray data improved the pathway reconstruction involved in carbohydrate utilization of Bacillus sp. N16-5 and revealed that the organism precisely regulates gene transcription in response to fluctuations in energy resources.

  3. Conditionally amplifiable BACs: switching from single-copy to high-copy vectors and genomic clones.

    Science.gov (United States)

    Wild, Jadwiga; Hradecna, Zdenka; Szybalski, Waclaw

    2002-09-01

    The widely used, very-low-copy BAC (bacterial artificial chromosome) vectors are the mainstay of present genomic research. The principal advantage of BACs is the high stability of inserted clones, but an important disadvantage is the low yield of DNA, both for vectors alone and when carrying genomic inserts. We describe here a novel class of single-copy/high-copy (SC/HC) pBAC/oriV vectors that retain all the advantages of low-copy BAC vectors, but are endowed with a conditional and tightly controlled oriV/TrfA amplification system that allows: (1) a yield of ~100 copies of the vector per host cell when conditionally induced with L-arabinose, and (2) analogous DNA amplification (only upon induction and with copy number depending on the insert size) of pBAC/oriV clones carrying >100-kb inserts. Amplifiable clones and libraries facilitate high-throughput DNA sequencing and other applications requiring HC plasmid DNA. To turn on DNA amplification, which is driven by the oriV origin of replication, we used copy-up mutations in the gene trfA whose expression was very tightly controlled by the araC-P(araBAD) promoter/regulator system. This system is inducible by L-arabinose, and could be further regulated by glucose and fucose. Amplification of DNA upon induction with L-arabinose and its modulation by glucose are robust and reliable. Furthermore, we discovered that addition of 0.2% D-glucose to the growth medium helped toward the objective of obtaining a real SC state for all BAC systems, thus enhancing the stability of their maintenance, which became equivalent to cloning into the host chromosome

  4. Purification, properties, and mode of action of hemicellulase I produced by Ceratocystis paradoxa.

    Science.gov (United States)

    Dekker, R F; Richards, G N

    1975-01-01

    A culture isolate (CP2) of the fungal plant pathogen Ceratocystis paradoxa produces at least five extra-cellular hemicellulases when grown on a medium containing a commercial hemicellulose as inducer. One of the five enzymes, hemicellulase I (HC-I), was purified by ammonium sulphate preceipitation, ion-exchange chromatography (DEAE-Sephadex and then Cellex-CM), and iso-electric focusing at pH 3-10 and 8-10. HC-I behaves as a single protein on a electrophoresis at pH 6.0 and 8.4. The enzyme degrades hemicellulose B (an arabino-4-O-methylglucurono-xylan) and arabinoxylanto arabinose, xylose, xylobiose (Xyl2; beta-D-Xylp-(1 leads to 4)-D-Xyl), and a mixture of arabinose-xylose and xylose oligosaccharides (AraXyln and Xyln, where n=3, 4, or 5). The enzyme is deduced to be an endo-enzyme. Xylotetraose (Xyl4) was the lowest homologue of the xylose oligosaccharides attacked, yielding xylobiose and xylotriose (Xyl3) only. A mechanism is postulated for this reaction. AraXyl5 were slowly hydrolysed to arabinose and the respective xylose saccharide (Xyl2-Xyl5), and thence to Xyl2 and Xyl3. Hydrolysis of the arabinofuranosyl linkage probably does not occur at the same active site as for the xylose oligosaccharides. Hemicellulose B fractions from different sources appeared to be degraded by HC-I. The enzyme showed optimum activity at pH 5.5 and 40 degrees, and Km was 4.24 mg of hemicellulose/ml.

  5. Extraction and characterization of polysaccharides from Semen Cassiae by microwave-assisted aqueous two-phase extraction coupled with spectroscopy and HPLC.

    Science.gov (United States)

    Chen, Zhi; Zhang, Wei; Tang, Xunyou; Fan, Huajun; Xie, Xiujuan; Wan, Qiang; Wu, Xuehao; Tang, James Z

    2016-06-25

    A novel and rapid method for simultaneous extraction and separation of the different polysaccharides from Semen Cassiae (SC) was developed by microwave-assisted aqueous two-phase extraction (MAATPE) in a one-step procedure. Using ethanol/ammonium sulfate system as a multiphase solvent, the effects of MAATPE on the extraction of polysaccharides from SC such as the composition of the ATPS, extraction time, temperature and solvent-to-material ratio were investigated by UV-vis analysis. Under the optimum conditions, the yields of polysaccharides were 4.49% for the top phase, 8.80% for the bottom phase and 13.29% for total polysaccharides, respectively. Compared with heating solvent extraction and ultrasonic assisted extraction, MAATPE exhibited the higher extraction yields in shorter time. Fourier-transform infrared spectra showed that two polysaccharides extracted from SC to the top and bottom phases by MAATPE were different from each other in their chemical structures. Through acid hydrolysis and PMP derivatization prior to HPLC, analytical results by indicated that a polysaccharide of the top phases was a relatively homogeneous homepolysaccharide composed of dominant gucose glucose while that of the bottom phase was a water-soluble heteropolysaccharide with multiple components of glucose, xylose, arabinose, galactose, mannose and glucuronic acid. Molar ratios of monosaccharides were 95.13:4.27:0.60 of glucose: arabinose: galactose for the polysaccharide from the top phase and 62.96:14.07:6.67: 6.67:5.19:4.44 of glucose: xylose: arabinose: galactose: mannose: glucuronic acid for that from the bottom phase, respectively. The mechanism for MAATPE process was also discussed in detail. MAATPE with the aid of microwave and the selectivity of the ATPS not only improved yields of the extraction, but also obtained a variety of polysaccharides. Hence, it was proved as a green, efficient and promising alternative to simultaneous extraction of polysaccharides from SC.

  6. Fermentation of dietary fibre components in the rat intestinal tract.

    Science.gov (United States)

    Nyman, M; Asp, N G

    1982-05-01

    1. The fermentative breakdown of dietary fibre from various sources in the intestinal tract was studied using rat balance experiments and gas-liquid chromatograhic analysis of dietary fibre monomers in feed and faces. 2. On a basal diet with 690 g maize starch/kg but no added fibre, small but detectable amounts of polymeric glucose, rhamnose, arabinose, xylose, galactose, mannose and uronic acids, i.e. sugars occurring in dietary fibre, were excreted in faeces. 3. Dietary fibre in wheat bran was rather resistant to fermentation; 63% was recovered in the faeces. Guar gum, on the other hand, was almost completely fermented, whereas 19 and 25% of the uronic acids in low and high methoxylated pectin respectively, were excreted in faeces. The various constituents of sugar-beet dietary fibre (approximately equal amounts of arabinose-based hemicellulose, pectin and non-starch glucan (cellulose)) showed quite variable availability for micro-organisms in that 6-12% of the arabinose, 17-25% of the uronic acids, and 52-58% of the cellulose were recovered in the faeces. 4. Faecal nitrogen excretion increased on addition of any one of the dietary fibre preparations studied, resulting in decreased true and apparent protein digestibility values. 5. The faecal dry weight increment was most pronounced when feeding bran and could then almost be accounted for by the remaining fibre and by protein. The less-prominent bulking effect of guar gum and pectins, that were much more extensively fermented, could be only partly explained by dietary fibre and protein.

  7. Regulated delayed expression of rfaH in an attenuated Salmonella enterica serovar typhimurium vaccine enhances immunogenicity of outer membrane proteins and a heterologous antigen.

    Science.gov (United States)

    Kong, Qingke; Liu, Qing; Roland, Kenneth L; Curtiss, Roy

    2009-12-01

    RfaH is a transcriptional antiterminator that reduces the polarity of long operons encoding secreted and surface-associated cell components of Salmonella enterica serovar Typhimurium, including O antigen and lipopolysaccharide core sugars. A DeltarfaH mutant strain is attenuated in mice (50% lethal dose [LD(50)], >10(8) CFU). To examine the potential for using rfaH in conjunction with other attenuating mutations, we designed a series of strains in which we replaced the native rfaH promoter with the tightly regulated arabinose-dependent araC P(BAD) promoter so that rfaH expression was dependent on exogenously supplied arabinose provided during in vitro growth. Following colonization of host lymphoid tissues, where arabinose was not available, the P(BAD) promoter was no longer active and rfaH was not expressed. In the absence of RfaH, O antigen and core sugars were not synthesized. We constructed three mutant strains that expressed different levels of RfaH by altering the ribosome-binding sequence and start codon. One mutation, DeltaP(rfaH178), was introduced into the attenuated vaccine strain chi9241 (DeltapabA DeltapabB DeltaasdA) expressing the pneumococcal surface protein PspA from an Asd(+) balanced-lethal plasmid. Mice immunized with this strain and boosted 4 weeks later induced higher levels of serum immunoglobulin G specific for PspA and for outer membrane proteins from other enteric bacteria than either an isogenic DeltarfaH derivative or the isogenic RfaH(+) parent. Eight weeks after primary oral immunization, mice were challenged with 200 LD(50) of virulent Streptococcus pneumoniae WU2. Immunization with DeltaP(rfaH178) mutant strains led to increased levels of protection compared to that of the parent chi9241 and of a DeltarfaH derivative of chi9241.

  8. In vitro and in vivo antioxidant activity of a water-soluble polysaccharide from dendrobium denneanum

    Science.gov (United States)

    Luo, A.; Ge, Z.; Fan, Y.; Chun, Z.; Jin, He X.

    2011-01-01

    The water-soluble crude polysaccharide (DDP) obtained from the aqueous extracts of the stem of Dendrobium denneanum through hot water extraction followed by ethanol precipitation, was found to have an average molecular weight (Mw) of about 484.7 kDa. Monosaccharide analysis revealed that DDP was composed of arabinose, xylose, mannose, glucose and galactose in a molar ratio of 1.00:2.66:8.92:34.20:10.16. The investigation of antioxidant activity both in vitro and in vivo showed that DDP is a potential antioxidant. ?? 2011.

  9. Development of microbial biosensors for food analysis

    DEFF Research Database (Denmark)

    Lukasiak, Justyna

    Microbial biosensors are analytical devices composed of a biological recognition element (microorganism) integrated to a signal transduction element (i.e. bioluminescence), converting a biochemical signal into quantifiable response. Due to their molecular properties they can be diversely designed...... grains. It is a dietary fiber, with potential as a functional food ingredient. In this study, reporter strains targeting specifically L-rhamnose, L-arabinose and Dxylose using three different signal transducers: bioluminescence (luxCDABE), fluorescence (gfp) and ice nucleation (inaZ) were developed...

  10. Reference: 163 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available ike et al. 2005 May. Planta 221(2):243-54. The nucleotide sugar UDP-glucuronic acid (UDP-GlcA) is the principal pre...cursor for galacturonic acid, xylose, apiose and arabinose residues of the plant cell-wall polymers. ...UDP-GlcA can be synthesized by two different functional pathways in Arabidopsis i...nvolving either UDP-glucose dehydrogenase or inositol oxygenase as the initial enzyme reaction to channel ca...rbohydrates into a pool of UDP sugars used for cell-wall biosynthesis. The genes for the enzyme myo-inositol oxygenase (MIOX) were

  11. Production and Utilization of Hemicelluloses from Renewable Resources for Sustainable Advanced Products

    DEFF Research Database (Denmark)

    Sárossy, Zsuzsa

    OH) solution with different solid to liquid ratios. The ratio of arabinoxylans (~65%) and β-glucans (~25%) was similar in the water-extracted and alkaliextracted materials; however, their arabinose/xylose (Ara/Xyl) ratio differed. The alkaliextracted arabinoxylan was less substituted with an Ara/Xyl ratio of 0.......35, while the waterextracted material had an Ara/Xyl ratio of 0.54. In order to analyse the monosaccharide composition of the isolated hemicelluloses, a method based on gas chromatography-mass spectrometry analysis of acetylated methyl glycosides was developed. The derivatives of the monosaccharides...

  12. Component Analysis and Free Radicals Scavenging Activity of Physalis alkekengi L.Polysaccharide

    Institute of Scientific and Technical Information of China (English)

    CHENG Ying-kun; LI Lei; MENG Zhao-kun; HOU A-li; WU Yu-jie; TENG Li-rong

    2008-01-01

    A crude polysaccharide was extracted from Physalis alkekengi L.fruit.HPLC Was used for the component analysis of the polysaccharide.The results indicate that Physalis alkekengi L.polysaccharide(PAP) was composed of rharnnose,xylose,arabinose,galactose,and glucose.Free radicals scavenging activity of PAP was studied through 3 free radicals scavenging tests.PAP exhibited high scavenging effects on·OH and DPPH radicals,and both the scavenging rates were about 80%.The scavenging rate of·O2- radical was about 22%.

  13. Metabolomics of Clostridial Biofuel Production

    Energy Technology Data Exchange (ETDEWEB)

    Rabinowitz, Joshua D [Princeton Univ., NJ (United States); Aristilde, Ludmilla [Cornell Univ., Ithaca, NY (United States); Amador-Noguez, Daniel [Univ. of Wisconsin, Madison, WI (United States)

    2015-09-08

    (xylose or arabinose) to C. acetobutylicum revealed that, as expected, glucose was preferred, with the pentose sugar selectively assimilated into the pentose phosphate pathway (PPP). Simultaneous feeding of xylose and arabinose revealed an unexpected hierarchy among these pentose sugars, with arabinose utilized preferentially over xylose. Pentose catabolism occurred via the phosphoketolase pathway (PKP), an alternative route of pentose catabolism that directly converts xylulose-5-phosphate into acetyl-phosphate and glyceraldehyde-3-phosphate. Taken collectively, these findings reveal two hierarchies in Clostridial pentose metabolism: xylose is subordinate to arabinose, and the PPP is used less than the PKP. Thus, in addition to massively expanding the available data on Clostridial metabolism, we identified three key regulatory points suitable for targeting in future bioengineering efforts: phosphofructokinase for enhancing fermentation, the pyruvate-oxaloacetate node for controlling solventogenesis, and the phosphoketolase reaction for driving pentose catabolism.

  14. Total Synthesis of 4"-O-Acetylmananthoside B Part Ⅱ: Synthesis of the Disaccharide Fragment

    Institute of Scientific and Technical Information of China (English)

    ZHAO,Gui-Long; YU,Zhao-Yun; LI,Yan; PANG,Li-Na; WANG,Jian-Wu

    2008-01-01

    A disaccharide compound, p-methoxyphenyl 2,3,4-tri-O-benzyl-β-L-arabinopyranosyl-(1→6)-2-O-benzyl-3,4-di-O-acetyl-β-D-galactopyranoside (17), was successfully synthesized from two monosaccharides L-arabinose and D-galactose and fully characterized. This compound can be used to build a natural product 4"-O-acetylmanan thoside B, which was isolated from the leaves and stems of a kind of Vietnamese Acanthaceae Justicia patentiflora.

  15. Free amino acids and sugars in the flower of Carthamus tinctorius L.

    Directory of Open Access Journals (Sweden)

    Yoshiyuki Takahasi

    2014-01-01

    Full Text Available Qualitative and quantitative analyses of free amino acids and sugars in the extracts from freshly collected florets of Carthamus tinctorius L. were performed by combination of thin-layer chromatography (TLC, automatic amino acid analysis and gas-liquid chromatography (GLC. Sixteen amino acids were detected and their quantitative relations were investigated. Alditol acetate derivatives of free sugars were examined by GLC. The retention time and resolution pattern of the following monosaccharides, rhamnose, arabinose, xylose, mannose and glucose, were ultimately investigated.

  16. Cryptococcus friedmannii, a new species of yeast from the Antarctic

    Science.gov (United States)

    Vishniac, H. S.

    1985-01-01

    Cryptococcus friedmannii Vishniac sp. nov. from an Antarctic cryptoendolithic community is a psychrophilic basidioblastomycete characterized by cream-colored colonies of cells with smooth, layered walls, budding monopolarly, producing amylose and extracellular proteinase, utilizing nitrate and D-alanine (inter alia) as nitrogen sources and L-arabinose, arbutin, cellobiose, D-glucuronate, maltose, melezitose, salicin, soluble starch, trehalose, and D-xylose as carbon sources. This species differs from all other basidiomycetous yeasts in possessing the following combination of characters: amylose production (positive), assimilation of cellobiose (positive), D-galactose (negative), myo-inositol (negative), D-mannitol (negative), and sucrose (negative).

  17. Isomerisation of aldoses in pyridine in the presence of aluminium oxide.

    Science.gov (United States)

    Ekeberg, Dag; Morgenlie, Svein; Stenstrøm, Yngve

    2005-02-28

    Addition of aluminium oxide to boiling pyridine solutions of D-xylose, L-arabinose, D-mannose and D-glucose strongly increased the reaction rate of the aldose-ketose transformation. The maximum content of 2-ketose was reached after less than 2h for the aldopentoses and 3h for the aldohexoses. D-Threo-2-pentulose (xylulose) was prepared from D-xylose, and isolated as its O-isopropylidene derivative, the yield was nearly twice that compared to that usually obtained in the classical Lobry de Bruyn-Alberda van Ekenstein transformation in pyridine.

  18. Enthalpy and entropy interaction parameters of sodium chloride with some monosaccharides in water

    Institute of Scientific and Technical Information of China (English)

    ZHUO; Kelei; WANG; Jianji; BAI; Guangyue; YAN; Haike; WANG

    2004-01-01

    Dilution enthalpies of sodium chloride and some monosaccharides (glucose, galactose, xylose, arabinose, and fructose) in water and mixing enthalpies of aqueous sodium chloride and these monosaccharide solutions were measured by using an improved precision semimicro-titration calorimeter. Transfer enthalpies of sodium chloride from water to aqueous saccharide solutions were evaluated as well as enthalpy interaction parameters of sodium chloride with these monosaccharides in water. Combined with Gibbs energy interaction parameters, entropy interaction parameters were also obtained. The results show that interactions of the saccharides with sodium chloride depend on the stereochemistry of saccharide molecules. These interaction parameters can identify stereochemical structure of saccharide molecules.

  19. [Gardnerella vaginalis biotypes: modification of a proposed system].

    Science.gov (United States)

    Pedraza-Avilés, A G; Inzunza-Montiel, A E; Ortíz-Zaragoza, M C; Morales-Espinosa, M R; Ponce-Rosas, E R

    1995-01-01

    A modified scheme is proposed for biotyping Gardnerella vaginalis based on detection of hippurate hydrolysis, beta-galactosidase (ONPG) and lipase, and fermentation of arabinose, galactose and xylose. Thirty three biotypes were found among 140 strains from women with and without bacterial vaginosis (non-specific vaginitis). The distribution of biotypes were found to be significantly different, being more predominant the biotypes 1A; 5G; 7A; 7D and 7G in women with vaginosis and the biotypes 5G and 6H in women without vaginosis. These data suggest that some biotypes of Gardnerella vaginalis are associated with bacterial vaginosis.

  20. Cultivation Conditions for Phytase Production from Recombinant Escherichia coli DH5α

    OpenAIRE

    Rafidah Mohd Ariff; Anwar Fitrianto; Mohd Yazid Abd. Manap; Aini Ideris; Azhar Kassim; Afinah Suhairin; Anis Shobirin Meor Hussin

    2013-01-01

    Response surface methodology (RSM) was used to optimize the cultivation conditions for the production of phytase by recombinant Escherichia coli DH5α. The optimum predicted cultivation conditions for phytase production were at 3 hours seed age, a 2.5% inoculum level, an L-arabinose concentration of 0.20%, a cell concentration of 0.3 (as measured at 600 nm) and 17 hours post-induction time with a predicted phytase activity of 4194.45 U/mL. The model was validated and the results showed no sign...

  1. Inhibition by natural dietary substances of gastrointestinal absorption of starch and sucrose in rats and pigs: 1. Acute studies.

    Science.gov (United States)

    Preuss, Harry G; Echard, Bobby; Bagchi, Debasis; Stohs, Sidney

    2007-08-06

    Rapid gastrointestinal absorption of refined carbohydrates (CHO) is linked to perturbed glucose-insulin metabolism that is, in turn, associated with many chronic health disorders. We assessed the ability of various natural substances, commonly referred to as "CHO blockers," to influence starch and sucrose absorption in vivo in ninety-six rats and two pigs. These natural enzyme inhibitors of amylase/sucrase reportedly lessen breakdown of starches and sucrose in the gastrointestinal tract, limiting their absorption. To estimate absorption, groups of nine SD rats were gavaged with water or water plus rice starch and/or sucrose; and circulating glucose was measured at timed intervals thereafter. For each variation in the protocol a total of at least nine different rats were studied with an equal number of internal controls on three different occasions. The pigs rapidly drank CHO and inhibitors in their drinking water. In rats, glucose elevations above baseline over four hours following rice starch challenge as estimated by area-under-curve (AUC) were 40%, 27%, and 85% of their internal control after ingesting bean extract, hibiscus extract, and l-arabinose respectively in addition to the rice starch. The former two were significantly different from control. L-Arabinose virtually eliminated the rising circulating glucose levels after sucrose challenge, whereas hibiscus and bean extracts were associated with lesser decreases than l-arabinose that were still significantly lower than control. The glucose elevations above baseline over four hours in rats receiving sucrose (AUC) were 51%, 43% and 2% of control for bean extract, hibiscus extract, and L-arabinose, respectively. Evidence for dose-response of bean and hibiscus extracts is reported. Giving the natural substances minus CHO challenge caused no significant changes in circulating glucose concentrations, indicating no major effects on overall metabolism. A formula combining these natural products significantly

  2. Inhibition by Natural Dietary Substances of Gastrointestinal Absorption of Starch and Sucrose in Rats and Pigs: 1. Acute Studies

    Directory of Open Access Journals (Sweden)

    Harry G. Preuss, Bobby Echard, Debasis Bagchi, Sidney Stohs

    2007-01-01

    Full Text Available Rapid gastrointestinal absorption of refined carbohydrates (CHO is linked to perturbed glucose-insulin metabolism that is, in turn, associated with many chronic health disorders. We assessed the ability of various natural substances, commonly referred to as “CHO blockers,” to influence starch and sucrose absorption in vivo in ninety-six rats and two pigs. These natural enzyme inhibitors of amylase/sucrase reportedly lessen breakdown of starches and sucrose in the gastrointestinal tract, limiting their absorption. To estimate absorption, groups of nine SD rats were gavaged with water or water plus rice starch and/or sucrose; and circulating glucose was measured at timed intervals thereafter. For each variation in the protocol a total of at least nine different rats were studied with an equal number of internal controls on three different occasions. The pigs rapidly drank CHO and inhibitors in their drinking water. In rats, glucose elevations above baseline over four hours following rice starch challenge as estimated by area-under-curve (AUC were 40%, 27%, and 85% of their internal control after ingesting bean extract, hibiscus extract, and l-arabinose respectively in addition to the rice starch. The former two were significantly different from control. L-Arabinose virtually eliminated the rising circulating glucose levels after sucrose challenge, whereas hibiscus and bean extracts were associated with lesser decreases than l-arabinose that were still significantly lower than control. The glucose elevations above baseline over four hours in rats receiving sucrose (AUC were 51%, 43% and 2% of control for bean extract, hibiscus extract, and L-arabinose, respectively. Evidence for dose-response of bean and hibiscus extracts is reported. Giving the natural substances minus CHO challenge caused no significant changes in circulating glucose concentrations, indicating no major effects on overall metabolism. A formula combining these natural products

  3. Transformation of aldose formazans. Novel synthesis of 2-acetamido-2-deoxypentonolactones and a new pent-2-enose formazan.

    Science.gov (United States)

    Zsoldos-Mády, Virág; Pintér, István; Peredy-Kajtár, Mária; Perczel, András

    2011-09-06

    2-Acetamido-2-deoxypentonolactones were synthesized from per-O-acetylated formazans of D-ribose, D- and L-arabinose, respectively. In dimethyl sulfoxide, a novel spontaneous transformation of the per-O-acetyl-pentose formazans into new 3,4,5-tri-O-acetyl-pent-2-enose formazans has been recognized. Additional examples for the occurrence of the isomerism between pseudo-aromatic chelate and open phenylazo-phenylhydrazone system were demonstrated by (1)H NMR spectroscopy in both the unprotected pentose formazans and 3,4,5-tri-O-acetyl-pent-2-enose formazans. Computational calculations supported higher stability of the ring form.

  4. Enzymatic Xylose Release from Pretreated Corn Bran Arabinoxylan: Differential Effects of Deacetylation and Deferuloylation on Insoluble and Soluble Substrate Fractions

    DEFF Research Database (Denmark)

    Agger, Jane; Viksø-Nielsen, Ander; Meyer, Anne S.

    2010-01-01

    In the present work enzymatic hydrolysis of arabinoxylan from pretreated corn bran (190 °C, 10 min) was evaluated by measuring the release of xylose and arabinose after treatment with a designed minimal mixture of monocomponent enzymes consisting of α-l-arabinofuranosidases, an endoxylanase......, and a β-xylosidase. The pretreatment divided the corn bran material 50:50 into soluble and insoluble fractions having A:X ratios of 0.66 and 0.40, respectively. Addition of acetyl xylan esterase to the monocomponent enzyme mixture almost doubled the xylose release from the insoluble substrate fraction...

  5. Olive stones as a source of fermentable sugars

    Energy Technology Data Exchange (ETDEWEB)

    Heredia-Moreno, A.; Guillen-Bejarano, R.; Fernandez-Bolanos, J.; Rivas-Moreno, M.

    1987-01-01

    The composition of the olive stone and its woody fraction has been investigated for the varieties Gordal, Manzanilla, Hojiblanca and Verdial. The neutral detergent fiber method (NDF) of Van Soest was used to estimate dietary fiber. Cellulose was the main component of the fiber, followed by hemicelluloses and lignin. The NDF was hydrolyzed enzymatically and the sugars identified by gas chromatography. Glucose was the main sugar (46-51% in the stone and 47-63% in the woody fraction), followed by galactose (25%) and xylose (14%). Arabinose and mannose were also detected.

  6. Isolation of a mutation resulting in constitutive synthesis of L-fucose catabolic enzymes.

    OpenAIRE

    Bartkus, J. M.; Mortlock, R P

    1986-01-01

    A ribitol-positive transductant of Escherichia coli K-12, JM2112, was used to facilitate the isolation and identification of mutations affecting the L-fucose catabolic pathway. Analysis of L-fucose-negative mutants of JM2112 enabled us to confirm that L-fucose-1-phosphate is the apparent inducer of the fucose catabolic enzymes. Plating of an L-fuculokinase-negative mutant of JM2112 on D-arabinose yielded an isolate containing a second fucose mutation which resulted in the constitutive synthes...

  7. Molecular Characterization of Arabinoxylans from Hull-Less Barley Milling Fractions

    OpenAIRE

    Zheng, Xueling; Li, Limin; Wang, Xiaoxi

    2011-01-01

    Arabinoxylans were prepared from different hull-less barley milling fractions (bran, shorts and flour). The yields of hull-less bran arabinoxylan (HBB-AX), shorts arabinoxylan (HBS-AX) and flour arabinoxylan (HBF-AX) were 8.42%, 4.08% and 2.13% respectively. Sugar composition analysis showed that arabinose and xylose were the main sugars. HBF-AX had the highest Ara/Xyl ratio, followed by HBS-AX and HBB-AX. Size exclusion chromatography analysis (HPSEC) showed that HBF-AX had the highest molec...

  8. Physico-chemical Properties and Bioactivities of a Glycoconjugate LbGp5B from Lycium barbarum L.

    Institute of Scientific and Technical Information of China (English)

    PENG,Xue-Mei(彭雪梅); PENG,Xue-Mei; QI,Chun-Hui(齐春会); QI,Chun-Hui; TIAN,Geng-Yuan (田庚元); TIAN,Geng-Yuan; ZHANG,Yong-Xiang(张永详); ZHANG,Yong-Xiang

    2001-01-01

    A glycoconjugatedesignated as LbGp5B was isolated from the fruit of Lyciun barbarum L. and purified to homogeneity by gel filtration .LbGp5B is composed of rhamnose (Rha), arabinose (Ara), galactose (Gal), glucose (Glc), galacturonic acid (GalA) and seveateen amino acids. The molecular weight of LbGp5B was determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and by matrix-asisted laser desorption/ionization (MALDI) time of fight (T OF) mass spectrometry (MS). The preliminary experiments showed that LbGp5B promoted splenocyte proliferation in mice and inhihited the peroxidation of low density lipoprotein (LDL).

  9. Strain identification in Rhizobium by starch gel electrophoresis of isoenzymes

    DEFF Research Database (Denmark)

    Engvild, Kjeld Christensen; Nielsen, G.

    1985-01-01

    Sonieated extracts of rhizobia, especiaUy Rhizobium leguminosarum from pea and vetch, were run in horizontal starch gel electrophoresis in the cold. The rhizobia were grown on agar on a slime suppressing substrate of tryptone-yeast extract-CaCl2 with small amounts of mannitol, sorbitol...... dehydrogenase (EC 1.1.1.30), mannitol dehydrogenase (EC 1.1.1.67), and arabinose dehydrogenase (EC 1.1.1.46). It was possible to distinguish at least 7 different types of pea rhizobia among 16 strains isolated from one batch of 5 kg soil....

  10. Metabolic Studies on Intermediates in the myo-Inositol Oxidation Pathway in Lilium longiflorum Pollen: II. Evidence for the Participation of Uridine Diphosphoxylose and Free Xylose as Intermediates.

    Science.gov (United States)

    Rosenfield, C L; Loewus, F A

    1978-01-01

    myo-Inositol-linked glucogenesis in germinated lily (Lilium longiflorum Thunb., cv. Ace) pollen was investigated by studying the effects of added l-arabinose or d-xylose on metabolism of myo-[2-(3)H]inositol and by determining the distribution of radioisotope in pentosyl and hexosyl residues of polysaccharides from pollen labeled with myo-[2-(14)C]inositol, myo-[2-(3)H]inositol, l-[5-(14)C]arabinose, and d-[5R,5S-(3)H]xylose.myo-[2-(14)C]Inositol and l-[5-(14)C]arabinose produced labeled glucose with similar patterns of distribution of (14)C, 35% in C1, and 55% in C6. Arabinosyl units were labeled exclusively in C5. Incorporation of (3)H into arabinosyl and xylosyl units in pollen labeled with myo-[2-(3)H]inositol was repressed when unlabeled l-arabinose was included in the germination medium and a related (3)H exchange with water was stimulated. Results are consistent with a process of glucogenesis in which the myo-inositol oxidation pathway furnishes UDP-d-xylose as a key intermediate for conversion to hexose via free d-xylose and the pentose phosphate pathway.Additional evidence for this process was obtained from pollen labeled with d-[5R,5S-(3)H]xylose or myo-[2-(3)H]inositol which produces d-[5R-(3)H]xylose. Glucosyl units from polysaccharides in the former had 11% of the (3)H in C1 and 78% in C6 while glucosyl units in the latter had only 4% in C1 and 78% in C6. Stereochemical considerations involving selective exchange with water of prochiral-R (3)H in C1 of fructose-6-P during conversion to glucose provide explanation for observed differences in the metabolism of these 5-labeled xyloses.Incorporation of (3)H from myo-[2-(3)H]inositol into arabinosyl and xylosyl units of pollen polysaccharides was unaffected by the presence of unlabeled d-xylose in the medium. Exchange of (3)H with water was greatly affected, decreasing from a value of 21% exchange in the absence of unlabeled d-xylose to 5% in the presence of 6.7 mmd-xylose.d-Xylose was rapidly utilized for

  11. YgbQ, a cell division protein in Escherichia coli and Vibrio cholerae, localizes in codependent fashion with FtsL to the division site

    OpenAIRE

    Buddelmeijer, Nienke; Judson, Nicholas; Boyd, Dana; Mekalanos, John J.; Beckwith, Jonathan

    2002-01-01

    YgbQ is a cell division protein in Escherichia coli and Vibrio cholerae. In E. coli the ygbQ gene was discovered as a result of a computer search of the E. coli genome designed to find potential interacting partners for cell division protein FtsL. In V. cholerae, ygbQ was identified as an essential gene by using a transposon that fuses genes to an arabinose promoter. The role of YgbQ in cell division is supported by the following. Cells depleted of YgbQ in both organisms form long filaments, ...

  12. Effect of water deficit on the cell wall of the date palm (Phoenix dactylifera 'Deglet nour', Arecales) fruit during development.

    Science.gov (United States)

    Gribaa, Ali; Dardelle, Flavien; Lehner, Arnaud; Rihouey, Christophe; Burel, Carole; Ferchichi, Ali; Driouich, Azeddine; Mollet, Jean-Claude

    2013-05-01

    Date palm (Phoenix dactylifera) is an important crop providing a valuable nutrition source for people in many countries including the Middle East and North Africa. In recent years, the amount of rain in North Africa and especially in the Tunisian palm grove areas has dropped significantly. We investigated the growth and cell wall remodelling of fruits harvested at three key development stages from trees grown with or without water supply. During development, cell wall solubilization and remodelling was characterized by a decrease of the degree of methylesterification of pectin, an important loss of galactose content and a reduction of the branching of xylan by arabinose in irrigated condition. Water deficit had a profound effect on fruit size, pulp content, cell wall composition and remodelling. Loss of galactose content was not as important, arabinose content was significantly higher in the pectin-enriched extracts from non-irrigated condition, and the levels of methylesterification of pectin and O-acetylation of xyloglucan were lower than in irrigated condition. The lower levels of hydrophobic groups (methylester and O-acetyl) and the less intensive degradation of the hydrophilic galactan, arabinan and arabinogalactan in the cell wall may be implicated in maintaining the hydration status of the cells under water deficit.

  13. Biogeochemical characteristics of sedimenting particles in Dona Paula Bay, India

    Science.gov (United States)

    D'souza, Fraddry; Garg, Anita; Bhosle, Narayan B.

    2003-10-01

    Sedimenting particles were collected at weekly intervals from October to May during 1995-1997 at a station in the coastal waters of Dona Paula Bay on the west coast of India. Sedimenting particles were analysed for concentration and composition of total sedimented particulate matter (TPM), biogenic silica (BSi) and total neutral carbohydrates (TCHO). TPM, BSi and TCHO fluxes showed seasonal and annual variations. Fluxes of BSi showed significant correlations with the fluxes of TCHO and fucose indicating that at the study site diatoms were associated with the production of carbohydrates. However, a high content of arabinose plus xylose (˜56% of TCHO without glucose) in some samples and their negative correlations with fucose may suggest terrestrial inputs. Sedimenting particles depleted in glucose content were enriched in rhamnose, fucose, xylose, mannose and galactose. A principal component analysis based on log-normalized wt% of monosaccharides established three factors that contributed 78% of total variance. The first factor was mostly controlled by the abundance of arabinose and xylose while the second and third factors were dependent on fucose, galactose, mannose and rhamnose. Carbohydrate composition data suggest that the nature and sources of organic matter at the study site varied over the period of study.

  14. Heterologous production and characterization of a chlorogenic acid esterase from Ustilago maydis with a potential use in baking.

    Science.gov (United States)

    Nieter, Annabel; Kelle, Sebastian; Takenberg, Meike; Linke, Diana; Bunzel, Mirko; Popper, Lutz; Berger, Ralf G

    2016-10-15

    Ustilago maydis, an edible mushroom growing on maize (Zea mays), is consumed as the food delicacy huitlacoche in Mexico. A chlorogenic acid esterase from this basidiomycete was expressed in good yields cultivating the heterologous host Pichia pastoris on the 5L bioreactor scale (reUmChlE; 45.9UL(-1)). In contrast to previously described chlorogenic acid esterases, the reUmChlE was also active towards feruloylated saccharides. The enzyme preferred substrates with the ferulic acid esterified to the O-5 position of arabinose residues, typical of graminaceous monocots, over the O-2 position of arabinose or the O-6 position of galactose residues. Determination of kcat/Km showed that the reUmChlE hydrolyzed chlorogenic acid 18-fold more efficiently than methyl ferulate, p-coumarate or caffeate. Phenolic acids were released by reUmChlE from natural substrates, such as destarched wheat bran, sugar beet pectin and coffee pulp. Treatment of wheat dough using reUmChlE resulted in a noticeable softening indicating a potential application of the enzyme in bakery and confectionery.

  15. Ethanol Production from Various Sugars and Cellulosic Biomass by White Rot Fungus Lenzites betulinus.

    Science.gov (United States)

    Im, Kyung Hoan; Nguyen, Trung Kien; Choi, Jaehyuk; Lee, Tae Soo

    2016-03-01

    Lenzites betulinus, known as gilled polypore belongs to Basidiomycota was isolated from fruiting body on broadleaf dead trees. It was found that the mycelia of white rot fungus Lenzites betulinus IUM 5468 produced ethanol from various sugars, including glucose, mannose, galactose, and cellobiose with a yield of 0.38, 0.26, 0.07, and 0.26 g of ethanol per gram of sugar consumed, respectively. This fungus relatively exhibited a good ethanol production from xylose at 0.26 g of ethanol per gram of sugar consumed. However, the ethanol conversion rate of arabinose was relatively low (at 0.07 g of ethanol per gram sugar). L. betulinus was capable of producing ethanol directly from rice straw and corn stalks at 0.22 g and 0.16 g of ethanol per gram of substrates, respectively, when this fungus was cultured in a basal medium containing 20 g/L rice straw or corn stalks. These results indicate that L. betulinus can produce ethanol efficiently from glucose, mannose, and cellobiose and produce ethanol very poorly from galactose and arabinose. Therefore, it is suggested that this fungus can ferment ethanol from various sugars and hydrolyze cellulosic materials to sugars and convert them to ethanol simultaneously.

  16. Bioproduction of D-Tagatose from D-Galactose Using Phosphoglucose Isomerase from Pseudomonas aeruginosa PAO1.

    Science.gov (United States)

    Patel, Manisha J; Patel, Arti T; Akhani, Rekha; Dedania, Samir; Patel, Darshan H

    2016-07-01

    Pseudomonas aeruginosa PAO1 phosphoglucose isomerase was purified as an active soluble form by a single-step purification using Ni-NTA chromatography that showed homogeneity on SDS-PAGE with molecular mass ∼62 kDa. The optimum temperature and pH for the maximum isomerization activity with D-galactose were 60 °C and 7.0, respectively. Generally, sugar phosphate isomerases show metal-independent activity but PA-PGI exhibited metal-dependent isomerization activity with aldosugars and optimally catalyzed the D-galactose isomerization in the presence of 1.0 mM MnCl2. The apparent Km and Vmax for D-galactose under standardized conditions were calculated to be 1029 mM (±31.30 with S.E.) and 5.95 U/mg (±0.9 with S.E.), respectively. Equilibrium reached after 180 min with production of 567.51 μM D-tagatose from 1000 mM of D-galactose. Though, the bioconversion ratio is low but it can be increased by immobilization and enzyme engineering. Although various L-arabinose isomerases have been characterized for bioproduction of D-tagatose, P. aeruginosa glucose phosphate isomerase is distinguished from the other L-arabinose isomerases by its optimal temperature (60 °C) for D-tagatose production being mesophilic bacteria, making it an alternate choice for bulk production.

  17. Immunologically related lectins from stems and roots of developing seedlings of Cucurbita ficifolia: purification and some properties of root and stem lectins

    Directory of Open Access Journals (Sweden)

    Irena Lorenc-Kubis

    2014-02-01

    Full Text Available Hemagglutinating activity has been found in acetate extracts from roots and stems of squash seedlings (Cucurbita ficifolia. The hemaglutinating activity changes during seeds germination and seedling development. Dot blot and Western blot techniques have shown that proteins from these vegetative tissues cross-reacted with antibodies raised against endogenous cotyledons lectin CLBa and Con A.Lectins were isolated from stems and roots of 6-day old seedlings by precipitation with ethanol, affinity chromatography on Con A-Sepharose, gel filtration on Bio-gel P100 and separated by electrophoresis on polyacrylamide gel. Three purified lectins (RLA1, RLA2, RLA3 were obtained from roots and four from stems (SLA1, SLA2, SLA3, SLA4. The purified lectins from roots and stems agglutinated all human red blood cells, but sheep erythrocytes were most sensitive to agglutination. The hemagglutination of the root lectins RLA2 and RLA3 was inhibited by a very low concentration of arabinose, while RLA1, of xylose and Ga1NAc. Arabinose and Xylose were also found to be the most effective inhibitors of all stem lectins.

  18. Dilute acid pretreatment of rye straw and bermudagrass for ethanol production

    Energy Technology Data Exchange (ETDEWEB)

    Ye Sun; Jay J Cheng [North Carolina State Univ., Dept. of Biological and Agricultural Engineering, Raleigh, NC (United States)

    2005-09-01

    Ethanol production from lignocellulosic materials provides an alternative energy production system. Rye and bermudagrass that are used in hog farms for nutrient uptake from swine wastewater have the potential for fuel ethanol production because they have a relative high cellulose and hemicellulose content. Dilute sulfuric acid pretreatment of rye straw and bermudagrass before enzymatic hydrolysis of cellulose was investigated in this study. The biomass at a solid loading rate of 10% was pretreated at 121 deg C with different sulfuric acid concentrations (0.6, 0.9, 1.2 and 1.5%, w/w) and residence times (30, 60, and 90 min). Total reducing sugars, arabinose, galactose, glucose, and xylose in the prehydrolyzate were analyzed. In addition, the solid residues were hydrolyzed by cellulases to investigate the enzymatic digestibility. With the increasing acid concentration and residence time, the amount of arabinose and galactose in the filtrates increased. The glucose concentration in the prehydrolyzate of rye straw was not significantly influenced by the sulfuric acid concentration and residence time, but it increased in the prehydrolyzate of bermudagrass with the increase of pretreatment severity. The xylose concentration in the filtrates increased with the increase of sulfuric acid concentration and residence time. Most of the arabinan, galactan and xylan in the biomass were hydrolyzed during the acid pretreatment. Cellulose remaining in the pretreated feedstock was highly digestible by cellulases from Trichoderma reesei. (Author)

  19. Isolation and Characterization of Phenolic Compounds and Anthocyanins from Murta (Ugni molinae Turcz. Fruits. Assessment of Antioxidant and Antibacterial Activity

    Directory of Open Access Journals (Sweden)

    Maria Paula Junqueira-Gonçalves

    2015-03-01

    Full Text Available Berry fruit consumption has become important in the promotion of human health, mainly due to their phenolic compounds, which have been associated with protection against different pathologies, as well as antimicrobial and other biological activities. Consequently, there has been a growing interest in identifying natural antioxidants and antimicrobials from these plants. This study aimed to characterize the phenolic chemical composition and anthocyanin profile of murta (Ugni molinae Turcz. fruit, and to evaluate the antioxidant and antimicrobial activity of its extracts (ethanolic and methanolic. LC/MS of the ethanolic extracts showed the presence of three major compounds: caffeic acid 3-glu, quercetin-3-glu and quercetin, while in the methanolic acid extract they were cyanidin-3-glucoside, pelargonidin-3-arabinose and delphinidin-3-glucoside. The antioxidant activity of ethanolic extracts (DPPH· and ORAC assays was higher than that of methanol acid extracts or purified anthocynins. Furthermore, the methanol acid extract showed an inhibitory activity against the bacteria E. coli and S. typhi similar to that of standard antibiotics. The results suggest that the antioxidant activity of the ethanolic extract is regulated by the high content of phenolic compounds and the fruit’s characteristic color is due to the content of pelargonidin-3-arabinose and delphinidin-3-glucoside. The obtained results demonstrated the appreciable antioxidant and antibacterial activities, providing opportunities to explore murta extracts as biopreservatives.

  20. Tensioactivos. XX. ω-Monoésteres grasos de ditioacetales de azúcares

    Directory of Open Access Journals (Sweden)

    Fernández-Bolaños, J.

    1995-10-01

    Full Text Available The preparation of 5-O-lauroyl(myhstoyl, palmitoyl-D-arabinose ethylendithioacetals, 6-O-lauroyl-D-glucose(D-galactose ethylendithioacetals and 6-O-decanoyl(lauroyl-D-mannose ethylendithioacetals is reported. The preparation of 5-O-octanoyl(decanoyl, lauroyl-L-arabinose diethyldithioacetais is also reported. These compounds were obtained by monoesterification of aldosedithioacetals with the corresponding fatty acid chlorides in pyridine.

    Se describe la preparación de etilenditioacetales de la 5-O-lauroil(miristoil, palmitoil- D-arabinosa, de la 6-O-lauroil-D-glucosa(D-galactosa y de la 6-O-decanoil(lauroil-D-manosa; y la preparación de dietilditioacetales de la 5-O-octanoil(decanoil, lauroil-L-arabinosa. La síntesis de estos compuestos se ha realizado por monoesterificación de los ditioacetales de azúcares con los correspondientes cloruros de ácidos grasos en piridina.

  1. L-Ribose isomerase and mannose-6-phosphate isomerase: properties and applications for L-ribose production.

    Science.gov (United States)

    Xu, Zheng; Sha, Yuanyuan; Liu, Chao; Li, Sha; Liang, Jinfeng; Zhou, Jiahai; Xu, Hong

    2016-11-01

    L-Ribose is a synthetic L-form monosaccharide. It is a building block of many novel nucleotide analog anti-viral drugs. Bio-production of L-ribose relies on a two-step reaction: (i) conversion of L-arabinose to L-ribulose by the catalytic action of L-arabinose isomerase (L-AI) and (ii) conversion of L-ribulose to L-ribose by the catalytic action of L-ribose isomerase (L-RI, EC 5.3.1.B3) or mannose-6-phosphate isomerase (MPI, EC 5.3.1.8, alternately named as phosphomannose isomerase). Between the two enzymes, L-RI is a rare enzyme that was discovered in 1996 by Professor Izumori's group, whereas MPI is an essential enzyme in metabolic pathways in humans and microorganisms. Recent studies have focused on their potentials for industrial production of L-ribose. This review summarizes the applications of L-RI and MPI for L-ribose production.

  2. On-line cut-off technique and organic modifier addition aided signal enhancement for trace analysis of carbohydrates in cellulase hydrolysate by ion exclusion chromatography-electrospray ionization mass spectrometry.

    Science.gov (United States)

    Cheng, Cheanyeh; Tsai, Hsiang-Rong; Chang, Kuo-Chung

    2006-06-30

    Paper cellulose has been hydrolyzed with calcium alginate immobilized cellulase to produce carbohydrate products and the three trace sugars, galactose, arabinose, and mannose in the cellulase hydrolysate have been analyzed by HPIEC/ESI-MS. Applying the on-line cut-off technique to the HPIEC/ESI-MS can cut the high concentration glucose off to eliminate its interference on the peaks of minor sugars and enhance their signals from 1.1- to 1.6-fold. However, the on-line post column addition of 15% ethanol to the eluate can increase the signal of the three trace sugars, galactose, arabinose, and mannose up to 17-, 23-, and 11-fold, respectively, and make the corresponding detection limits as 0.04, 0.04, and 0.03 ppm. The accuracies of the quantitative analysis for the three trace sugars with the signal enhanced HPIEC/ESI-MS by the two enhancement methods were larger than 95%. The precisions of the analytical results were also greatly improved by the assistance of the two techniques and were less than 6.5%. The quantitative analysis of the three trace sugars was performed with the internal standard method and the internal standard (IS) was sorbitol. Overall, the signal enhancement of HPIEC/ESI-MS and quantification of the three trace sugars by the on-line cut-off technique and organic modifier addition was successful.

  3. Dilute Sulfuric Acid Pretreatment of Agricultural and Agro-Industrial Residues for Ethanol Production

    Science.gov (United States)

    Martin, Carlos; Alriksson, Björn; Sjöde, Anders; Nilvebrant, Nils-Olof; Jönsson, Leif J.

    The potential of dilute-acid prehydrolysis as a pretreatment method for sugarcane bagasse, rice hulls, peanut shells, and cassava stalks was investigated. The prehydrolysis was performed at 122°C during 20, 40, or 60 min using 2% H2SO4 at a solid-to-liquid ratio of 1∶10. Sugar formation increased with increasing reaction time. Xylose, glucose, arabinose, and galactose were detected in all of the prehydrolysates, whereas mannose was found only in the prehydrolysates of peanut shells and cassava stalks. The hemicelluloses of bagasse were hydrolyzed to a high-extent yielding concentrations of xylose and arabinose of 19.1 and 2.2 g/L, respectively, and a xylan conversion of more than 80%. High-glucose concentrations (26-33.5 g/L) were found in the prehydrolysates of rice hulls, probably because of hydrolysis of starch of grain remains in the hulls. Peanut shells and cassava stalks rendered low amounts of sugars on prehydrolysis, indicating that the conditions were not severe enough to hydrolyze the hemicelluloses in these materials quantitatively. All prehydrolysates were readily fermentable by Saccharomyces cerevisiae. The dilute-acid prehydrolysis resulted in a 2.7-to 3.7-fold increase of the enzymatic convertibility of bagasse, but was not efficient for improving the enzymatic hydrolysis of peanut shells, cassava stalks, or rice hulls.

  4. Changes in enzymic activities of nucleoside diphosphate sugar interconversions during differentiation of cambium to xylem in sycamore and poplar.

    Science.gov (United States)

    Dalessandro, G; Northcote, D H

    1977-02-15

    During the transition from primary wall formation to secondary thickening there is a marked shift in the synthesis of pectin, hemicellulose and cellulose. The activities of the enzymes [UDP-D-galactose 4-epimerase (EC 5.1.3.2)8 UDP-l-arabinose 4-epimerase (EC 5.1.3.5), UDP-D-glucose dehydrogenase (EC 1.1.1.22) and UDP-D--glucuronate decarboxylase (EC 4.1.1.35)] were measured in cambial cells, differentiating xylem cells and differentiated xylem cells isolated from sycamore and poplar trees, and phloem cells from poplar. At the final stage of the differentiation of cambium to xylem there was a decrease in activity of the enzymes directly involved in producing the soluble precursors of pectin (DUP-D-galactose 4-epimerase and UDP-L-arabinose 4-epimerase and an increase in those producing the precursors of hemicellulose (UDP-D-glucose dehydrogenase and UDP-D-glucuronate decarboxylase). These results strongly suggest ahat the changes were correlated with the differences observed in the chemical composition of the wall during development. The changes found in the catalytic activity of the enzymes of nucleoside diphosphate sugar interconversion exert a coarse control over the synthesis of pectin and hemicelluloses. The tissues at all stages of development contained the necessary enzyme activities to produce all the precursors of pectin and hemicellulose, even at the final stage of differentiation when no pectin was formed.

  5. Cell wall polysaccharides of common beans (Phaseolus vulgaris L. Polissacarídeos de parede celular de feijões (Phasealus vulgaris L.

    Directory of Open Access Journals (Sweden)

    Tânia M. Shiga

    2003-08-01

    Full Text Available The soluble and insoluble cotyledon (SPF-Co and IPF-Co and tegument (SPF-Te and IPF-Te cell wall polymer fractions of common beans (Phaseolus vulgaris were isolated using a chemical-enzymatic method. The sugar composition showed that SPF-Co was constituted of 38.6% arabinose, 23.4% uronic acids, 12.7% galactose, 11.2% xylose, 6.4% mannose and 6.1% glucose, probably derived from slightly branched and weakly bound polymers. The IPF-Co was fractionated with chelating agent (CDTA and with increasing concentrations of NaOH. The bulk of the cell wall polymers (29.4% were extracted with 4.0M NaOH and this fraction contained mainly arabinose (55.0%, uronic acid (18.9%, glucose (10.7%, xylose (10.3% and galactose (3.4%. About 8.7% and 10.6% of the polymers were solubilised with CDTA and 0.01M NaOH respectively and were constituted of arabinose (52.0 and 45.9%, uronic acids (25.8 and 29.8%, xylose (9.6 and 10.2%, galactose (6.1 and 3.9% and glucose (6.5 and 3.8%. The cell wall polymers were also constituted of small amounts (5.6 and 7.2% of cellulose (CEL and of non-extractable cell wall polymers (NECW. About 16.8% and 17.2% of the polymers were solubilised with 0.5 and 1.0M NaOH and contained, respectively, 92.1 and 90.7% of glucose derived from starch (IST. The neutral sugar and polymers solubilization profiles showed that weakly bound pectins are present mainly in SPF-Co (water-soluble, CDTA and 0.01-0.1M NaOH soluble fractions. Less soluble, highly cross-linked pectins were solubilised with 4.0M NaOH. This pectin is arabinose-rich, probably highly branched and has a higher molecular weight than the pectin present in SPF-Co, CDTA and 0.01-0.1M NaOH fractions.Foram isoladas por método enzimático-químico as frações da parede celular de feijão (Phaseolus vulgaris L. contendo polímeros solúveis e insolúveis obtidos do cotilédone (SPF-Co e IPF-Co e tegumento (SPF-Te e IPF-Te. A análise da composição de açúcares mostrou que a SPF-Co era

  6. Hydrogen production from the monomeric sugars hydrolyzed from hemicellulose by Enterobacter aerogenes

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Yunli; Wang, Jianji; Liu, Zhen; Ren, Yunlai; Li, Guozhi [School of Chemical Engineering and Pharmaceutics, Henan University of Science and Technology, Luoyang 471039, Henan (China)

    2009-12-15

    Relatively large percentages of xylose with glucose, arabinose, mannose, galactose and rhamnose constitute the hydrolysis products of hemicellulose. In this paper, hydrogen production performance of facultative anaerobe (Enterobacter aerogenes) has been investigated from these different monomeric sugars except glucose. It was shown that the stereoisomers of mannose and galactose were more effective for hydrogen production than those of xylose and arabinose. The substrate of 5 g/l xylose resulted in a relative high level of hydrogen yield (73.8 mmol/l), hydrogen production efficiency (2.2 mol/mol) and a maximum hydrogen production rate (249 ml/l/h). The hydrogen yield, hydrogen production efficiency and the maximum hydrogen production rate reached 104 mmol/l, 2.35 mol/mol and 290 ml/l/h, respectively, on a substrate of 10 g/l galactose. The hydrogen yields and the maximum hydrogen production rates increased with an increase of mannose concentrations and reached 119 mmol/l and 518 ml/l/h on the culture of 25 g/l mannose. However, rhamnose was a relative poor carbon resource for E. aerogenes to produce hydrogen, from which the hydrogen yield and hydrogen production efficiency were about one half of that from the mannose substrate. E. aerogenes was found to be a promising strain for hydrogen production from hydrolysis products of hemicellulose. (author)

  7. Recombinant methods in protein and whole-cell biosensing

    Science.gov (United States)

    Shetty, R. S.; Salins, Lyndon L.; Ramanathan, S.; Daunert, Sylvia

    1999-12-01

    In this paper, we investigate the use of fluorescently- labeled binding proteins and genetically engineered bacterial cells for sensing of phosphate, glucose, and L- arabinose. To optimize the performance of the labeled binding proteins for biosensing purposes, a few key considerations were taken into account. A site-selective labeling protocol of the fluorescent reporter to the protein was used to ensure that the probe reported from a specific domain of the protein. The labeling sites chosen were hypothesized to undergo a physicochemical change when the biorecognition element binds the analyte. Cysteine mutations were introduced into the binding proteins by site-directed mutagenesis using the polymerase chain reaction. The residues selected were all in close proximity to the binding cleft, a region that is affected the most by the conformational change that accompanies ligand binding. The cysteine residues were then labeled with environment- sensitive fluorophores and changes in the fluorescence properties of the conjugates were monitored and related to the amount of ligand present. The application of microorganisms in sensing systems represent new advances in the development of novel analytical techniques for the detection of a target analyte. In these systems, a genetically engineered organism generates an analytically useful signal when it encounters a specific target substance due to selective recognition and binding properties towards that particular compound. This concept has been demonstrated using an optical bacteria-based sensing system capable of detecting the monosaccharide L-arabinose that employed the green fluorescent protein as a reporter protein.

  8. Polymyxin resistance of Pseudomonas aeruginosa phoQ mutants is dependent on additional two-component regulatory systems

    DEFF Research Database (Denmark)

    Gutu, Alina D; Sgambati, Nicole; Strasbourger, Pnina;

    2013-01-01

    systems, ColRS and CprRS. Deletion of the colRS genes, individually or in tandem, abrogated the polymyxin resistance of a ΔphoQ mutant, as did individual or tandem deletion of cprRS. Individual deletion of colR or colS in a ΔphoQ mutant also suppressed 4-amino-L-arabinose addition to lipid A, consistent...... with the known role of this modification in polymyxin resistance. Surprisingly, tandem deletion of colRS or cprRS in the ΔphoQ mutant or individual deletion of cprR or cprS failed to suppress 4-amino-L-arabinose addition to lipid A, indicating that this modification alone is not sufficient for Pho......PQ-mediated polymyxin resistance in P. aeruginosa. Episomal expression of colRS or cprRS in tandem or of cprR individually complemented the Pm resistance phenotype in the ΔphoQ mutant, while episomal expression of colR, colS, or cprS individually did not. Highly polymyxin-resistant phoQ mutants of P. aeruginosa...

  9. Process optimization and kinetic modelling of cyclic (1→3, 1→6)-β-glucans production from Bradyrhizobium japonicum MTCC120.

    Science.gov (United States)

    Nair, Anju V; Gummadi, Sathyanarayana N; Doble, Mukesh

    2016-05-20

    Cyclic (1→3, 1→6)-β-glucans are water soluble, biocompatible polymers with potential applications in food and pharmaceutical industries but have not yet been exploited due to their poor yield. In the present study statistical experimental design methodology was employed to improve their production. Initial screening indicated arabinose and peptone as best carbon and nitrogen source respectively, for glucan production. Arabinose and osmolyte concentrations as well as pH significantly contributed to the glucan production. Central composite design indicated a significant interaction between osmolyte concentration and pH on glucan production. The maximum amount of cyclic glucan produced was 6.7g/L in a 2.5L reactor in batch conditions. The logistic equation for cell growth and Luedeking-Piret equation for glucan production could satisfactorily simulate the batch kinetics data. Cyclic β-glucans could efficiently encapsulate a hydrophobic molecule, curcumin and increase its solubility in water, thus indicating that these glucans have potential as drug delivery systems.

  10. Effect of enzyme additions on the oligosaccharide composition of Monastrell red wines from four different wine-growing origins in Spain.

    Science.gov (United States)

    Apolinar-Valiente, Rafael; Williams, Pascale; Mazerolles, Gérard; Romero-Cascales, Inmaculada; Gómez-Plaza, Encarna; López-Roca, José María; Ros-García, José María; Doco, Thierry

    2014-08-01

    The release of oligosaccharides during winemaking depends on the grape skin cell wall degradation, which can be facilitated by the use of enzymes. Oligosaccharide quantities and composition in wine could be influenced by the "terroir" effect. Monastrell wine was elaborated from grapes from four different "terroirs" (Cañada Judío, Albatana, Chaparral-Bullas and Montealegre). Monastrell wines were also treated with β-galactosidase enzyme addition and commercial enzyme addition. The results showed significant differences in the Monastrell wine oligosaccharide fractions, according to the geographical origin of grapes. A higher quantity of oligosaccharides was found for three out of four terroirs studied when commercial enzymes were added. The use of commercial enzyme modified the Arabinose/Galactose and the Rhamnose/Galacturonic acid ratios in Cañada Judío and Albatana terroirs wines, and it modified the (Arabinose+Galactose)/Rhamnose ratio in Cañada Judío, Albatana and Chaparral-Bullas terroirs wines. Therefore, the "terroir" impacts the effect of commercial enzyme treatment on wine oligosaccharide composition.

  11. Engineering nonphosphorylative metabolism to generate lignocellulose-derived products.

    Science.gov (United States)

    Tai, Yi-Shu; Xiong, Mingyong; Jambunathan, Pooja; Wang, Jingyu; Wang, Jilong; Stapleton, Cole; Zhang, Kechun

    2016-04-01

    Conversion of lignocellulosic biomass into value-added products provides important environmental and economic benefits. Here we report the engineering of an unconventional metabolism for the production of tricarboxylic acid (TCA)-cycle derivatives from D-xylose, L-arabinose and D-galacturonate. We designed a growth-based selection platform to identify several gene clusters functional in Escherichia coli that can perform this nonphosphorylative assimilation of sugars into the TCA cycle in less than six steps. To demonstrate the application of this new metabolic platform, we built artificial biosynthetic pathways to 1,4-butanediol (BDO) with a theoretical molar yield of 100%. By screening and engineering downstream pathway enzymes, 2-ketoacid decarboxylases and alcohol dehydrogenases, we constructed E. coli strains capable of producing BDO from D-xylose, L-arabinose and D-galacturonate. The titers, rates and yields were higher than those previously reported using conventional pathways. This work demonstrates the potential of nonphosphorylative metabolism for biomanufacturing with improved biosynthetic efficiencies.

  12. Metabolic engineering for improved production of ethanol by Corynebacterium glutamicum.

    Science.gov (United States)

    Jojima, Toru; Noburyu, Ryoji; Sasaki, Miho; Tajima, Takahisa; Suda, Masako; Yukawa, Hideaki; Inui, Masayuki

    2015-02-01

    Recombinant Corynebacterium glutamicum harboring genes for pyruvate decarboxylase (pdc) and alcohol dehydrogenase (adhB) can produce ethanol under oxygen deprivation. We investigated the effects of elevating the expression levels of glycolytic genes, as well as pdc and adhB, on ethanol production. Overexpression of four glycolytic genes (pgi, pfkA, gapA, and pyk) in C. glutamicum significantly increased the rate of ethanol production. Overexpression of tpi, encoding triosephosphate isomerase, further enhanced productivity. Elevated expression of pdc and adhB increased ethanol yield, but not the rate of production. Fed-batch fermentation using an optimized strain resulted in ethanol production of 119 g/L from 245 g/L glucose with a yield of 95% of the theoretical maximum. Further metabolic engineering, including integration of the genes for xylose and arabinose metabolism, enabled consumption of glucose, xylose, and arabinose, and ethanol production (83 g/L) at a yield of 90 %. This study demonstrated that C. glutamicum has significant potential for the production of cellulosic ethanol.

  13. Alkali extraction and physicochemical characterization of hemicelluloses from young bamboo (Phyllostachys pubescens Mazel

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    Qiang Luo

    2012-11-01

    Full Text Available Two hemicellulose fractions were obtained by extraction of one-month- old young bamboo (Phyllostachys pubescens Mazel. The fractionation procedure employed 2% NaOH as extractant, followed by filtration, acidification, precipitation, and washing with 70% ethanol solution. The total yield was 26.2%, based on the pentosan content in bamboo. The physicochemical properties were determined and sugar composition analysis showed that the hemicelluloses consisted mainly of xylose, arabinose, galactose, and a small amount of uronic acid. Furthermore, based on FT-IR and NMR spectra analyses, the structure of hemicelluloses was determined to be mainly arabinoxylans linked via (1→4-β-glycosidic bonds with branches of arabinose and 4-O-methyl-D-glucuronic acid. The molecular weights were 6387 Da and 4076 Da, corresponding to the hemicelluloses HA and HB. Finally, the thermal stability was elucidated using the TG-DTG method. The obtained results can provide important information for understanding young bamboo and the hemicelluloses in it.

  14. Preparation of Reducing Sugar Solution by Acidic Hydrolyzing Corn Cob and Its Application in Tobacco Reaction Flavor%酸法水解玉米芯制备还原糖液及其在烟用反应型香料中的应用

    Institute of Scientific and Technical Information of China (English)

    徐利; 侯亚龙; 罗昌荣

    2011-01-01

    Corn cob was one kind of ideal raw materials for processing flavor precursor because of its rich xylose and arabinose. The extracted pentosans were hydrolyzed by diluted acid to obtain reducing sugars hydrolysates. HPLC-ELSD analysis results revealed that xylose and arabinose were rich in the hydrolysates. The standardized solutions of reducing sugars were utilized in the process of different reaction flavors. Therefore, one cheap raw materials of pentose for reaction flavors was developed.%玉米芯中富含木糖和阿拉伯糖,研究表明玉米芯是生产Maillard反应香料前驱体-戊糖的良好原料.以玉米芯为原料,提取得到戊聚糖,运用稀酸水解法获得还原糖液.HPLC-ELSD法测定表明还原糖液富舍木糖和阿拉伯糖.将标准化的还原糖液与氨基酸混和后,经Maillard反应获得了不同风味的反应型香料,为反应型香料的生产找到了一种廉价易得的戊糖原料,并为农产品加工废弃物-玉米芯找到了新的利用途径.

  15. Cj1411c GENE OF CAMPYLOBACTER JEJUNI 11168 ENCODES FOR A CYTOCHROME P450 INVOLVED IN BACTERIAL CAPSULE SUGAR METABOLISM

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    N. CORCIONIVOSCHI

    2013-12-01

    Full Text Available After isolation in 1970s, Campylobacter jejuni become the most commonlyrecognized cause of bacterial gastroenteritis in man. In animals is frequently foundin bovines on ovines. Publishing of the genome sequence of Campylobacter jejuni11168 (Parkhill, 2000 revealed the presence of only one cytochrome P450 in anoperon involved in sugar and cell surface biosynthesis. The gene name is Cj1411c, is1359 bp long and encodes 453 aa. The sequence is strictly conserved inCampylobacter jejuni RM221. Similarities with two cytochrome P450s, one formSilicobacter sp. and one form Poloromonas sp., were identified. These two enzymesare known to be involved in ascorbate and aldarate metabolism. The recombinantconstruct allowed the expression of active P450 enzyme with a 450 nm peak whenbinds CO. The protein was purified in proportion of ~ 70 %. By deleting the P450gene from the Campylobacter jejuni 11168 genome clear changes in cellmorphology were identified cells becoming wider and shorter. The capsular sugarprofile of the NCI strain reveals the presence of arabinose which was not found inthe wild type strain. The arabinose was identified by both High Performance LiquidChromatography (HPLC and Nuclear Magnetic Resonance (NMR.

  16. Morphological, physico-chemical and structural characterization of mucilage isolated from the seeds of Buchanania lanzan Spreng

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    Sudarshan Singh

    2014-01-01

    Full Text Available Context: Mucilage isolated from the seeds of Buchanania lanzan a wild Indian plant. This mucilage can be commercially exploited, by evaluating physico-chemical properties of this mucilage. Materials and Methods: Various physico-chemical parameter using scanning electron microscopy (SEM, molecular weight, X-ray diffraction (XRD spectrometry, zeta potential (ZP, Fourier transform infrared (FT-IR spectroscopy and 1D ( 1 H and 13 C nuclear magnetic resonance (NMR have been employed to characterize mucilage in the present study. Results: SEM analysis suggests that the mucilage has irregular particle size. Thermogravimetry analysis suggested that mucilage had good thermal stability with two stage decomposition. The weight-average molecular weight of mucilage was determined to be 4883, by gel permeation chromatography. The XRD pattern of the mucilage indicated a completely amorphous structure. The ZP was obtained 1.56 and −9.49 mV in water and 0.1 N NaCl respectively. The major functional groups identified from FT-IR spectrum include 3459/cm (-OH, 1667/cm (Alkenyl C-H and C = C stretch, 1407/cm (-COO- and 1321/cm (-CH 3 CO. Analysis of mucilage by paper chromatography and 1D NMR indicated the presence of rhamnose, arabinose and fructose. Conclusion: The spectral and chromatography analysis of mucilage indicate that the mucilage is composed of basic sugar moiety such as (arabinose, rhamnose, fructose and mannose as complex carbohydrates.

  17. Chemical structure and antioxidant activity of a new exopolysaccharide produced from Micrococcus luteus

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    Mohsen Mohamed Selim Asker

    2014-12-01

    Full Text Available An exopolysaccharide (EPS reaching a maximum of 13 g/L was isolated from Micrococcus luteus by ethanol precipitation. The crude EPS was purified by chromatography on DEAE-cellulose and Sephacryl S-200, affording a polysaccharide active fraction (AEP with a molecular weight of ∼137 kDa. AEP was investigated by a combination of chemical and chromatographic methods including FTIR, HPLC, periodate oxidation, methylation and GC–MS. Data obtained indicated that AEP was composed of mannose, arabinose, glucose and glucuronic acid in a molar ratio of 3.6:2.7:2.1:1.0, respectively. The main backbone consists of mannose units linked with (1→6-glycosidic bonds and arabinose units linked with (1→5-glycosidic bonds. There is a side chain consisting of mannose units linked with (1→6-glycosidic bonds at C3, when all glucose and most of glucuronic acid are found in the side chain. The in vitro antioxidant assay showed that AEP possesses DPPH radical-scavenging activity, with an EC50 value of 180 μg/mL.

  18. Composition of Lycium barbarum polysaccharides and their apoptosis-inducing effect on human hepatoma SMMC-7721 cells

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    Qian Zhang

    2015-11-01

    Full Text Available Background: Lycium barbarum polysaccharide (LBP is a natural functional component that has a variety of biological activities. The molecular structures and apoptosis-inducing activities on human hepatoma SMMC-7721 cells of two LBP fractions, LBP-d and LBP-e, were investigated. Results: The results showed that LBP-d and LBP-e both consist of protein, uronic acid, and neutral sugars in different proportions. The structure of LBP was characterized by gas chromatography, periodate oxidation, and Smith degradation. LBP-d was composed of eight kinds of monosaccharides (fucose, ribose, rhamnose, arabinose, xylose, mannose, galactose, and glucose, while LBP-e was composed of six kinds of monosaccharides (fucose, rhamnose, arabinose, mannose, galactose, and glucose. LBP-d and LBP-e blocked SMMC-7721 cells at the G0/G1 and S phases with an inhibition ratio of 26.70 and 45.13%, respectively, and enhanced the concentration of Ca2 + in the cytoplasm of SMMC-7721. Conclusion: The contents of protein, uronic acid, and galactose in LBP-e were much higher than those in LBP-d, which might responsible for their different bioactivities. The results showed that LBP can be provided as a potential chemotherapeutic agent drug to treat cancer.

  19. Structural diversity of pectins isolated from the Styrian oil-pumpkin (Cucurbita pepo var. styriaca) fruit.

    Science.gov (United States)

    Košťálová, Zuzana; Hromádková, Zdenka; Ebringerová, Anna

    2013-03-01

    To evaluate the seeded fruit biomass of the Styrian oil-pumpkin in view of its pectin component, a series of acidic polysaccharides were isolated by a six-step sequential extraction using hot water, EDTA, dilute HCl (twice) and dilute and stronger NaOH solutions. Chemical, physicochemical and spectroscopy analyses revealed that the first four fractions comprised partially methyl-esterified and acetylated pectins with varying proportions of rhamnogalacturonan regions ramified with galactose- and arabinose-containing side chains and showed considerable polymolecularity. The alkali-extracted polysaccharides contained lower amounts of pectins with homogalacturonan and arabinose-rich rhamnogalacturonan regions next to hemicelluloses prevailing in the last polysaccharide. Using (1)H-(13)C HSQC and HMBC spectroscopy, the resonances of free and methylesterified galacturonic acid residues in the purified acid-extracted pectin were unambiguously established and various diads formed by both residues identified. The results might serve as a basis for searching technological conditions to produce pectin from the oil-pumpkin fruit biomass.

  20. Cold exposure increases intestinal paracellular permeability to nutrients in the mouse.

    Science.gov (United States)

    Price, Edwin R; Ruff, Lisa J; Guerra, Alberto; Karasov, William H

    2013-11-01

    In situations of increased energy demand and food intake, animals can often acclimate within several days. The intestine generally responds to elevated digestive demand by increasing in size. However, there is likely a limit to how quickly the intestine can grow to meet the new demand. We investigated the immediate and longer-term changes to intestinal properties of the mouse when suddenly exposed to 4°C. We hypothesized that paracellular permeability to nutrients would increase as part of an immediate response to elevated absorptive demand. We measured absorption of l-arabinose, intestinal size and gene expression of several tight junction proteins (claudin-2, claudin-4, claudin-15 and ZO-1) at three time points: pre-exposure, and after 1 day and 2 weeks of cold exposure. Cold exposure increased food intake by 62% after 2 weeks but intake was not significantly increased after 1 day. Intestinal wet mass was elevated after 1 day and throughout the experiment. Absorption of arabinose rose by 20% after 1 day in the cold and was 33% higher after 2 weeks. Expression of claudin-2 increased after 1 day of cold exposure, but there were no changes in expression of any claudin genes when normalized to ZO-1 expression. Our results indicate that intestinal mass can respond rapidly to increased energy demand and that increased paracellular permeability is also part of that response. Increased paracellular permeability may be a consequence of enterocyte hyperplasia, resulting in more tight junctions across which molecules can absorb.

  1. Functional properties and characterization of dietary fiber from Mangifera pajang Kort. fruit pulp.

    Science.gov (United States)

    Al-Sheraji, Sadeq Hassan; Ismail, Amin; Manap, Mohd Yazid; Mustafa, Shuhaimi; Yusof, Rokiah Mohd; Hassan, Fouad Abdulrahman

    2011-04-27

    A dried high fiber product from bambangan (Mangifera pajang Kort.) fruit pulp was prepared and evaluated for proximate composition, functional properties, and soluble and insoluble dietary fiber composition. Mangifera pajang fibrous (MPF) consisted of 4.7% moisture, 0.8% fat, 4% protein, and 30 mg total polyphenol per g of dry sample, and 9, 79 and 88% soluble, insoluble and total dietary fiber, respectively. Water holding capacity, oil holding capacity, swelling, and solubility were found to be 9 g/g dry sample, 4 g/g dry sample, 16 mL/g dry sample, and 11%, respectively. The glucose dialysis retardation index of MPF was approximately double that of cellulose fiber. Soluble dietary fiber contained mannose, arabinose, glucose, rhamnose, erythrose, galactose, xylose, and fucose at 1.51, 0.72, 0.39, 0.16, 0.14, 0.05, 0.04, and 0.01%, respectively, with 5.8% uronic acid, while insoluble dietary fiber was composed of arabinose (18.47%), glucose (4.46%), mannose (3.15%), rhamnose (1.65%), galactose (1.20%), xylose (0.99%), and fucose (0.26%) with 15.5% uronic acid and 33.1% klason lignin. These characteristics indicate that MPF is a rich source of dietary fiber and has physicochemical properties which make it suitable as an added ingredient in various food products and/or dietetic, low-calorie high-fiber foods to enhance their nutraceutical properties.

  2. Changes in the sugar composition and molecular mass distribution of matrix polysaccharides during cotton fiber development.

    Science.gov (United States)

    Tokumoto, Hayato; Wakabayashi, Kazuyuki; Kamisaka, Seiichiro; Hoson, Takayuki

    2002-04-01

    Cotton (Gossypium herbaceum L.) fiber development consists of a fiber elongation stage (up to 20 d post-anthesis) and a subsequent cell wall thickening stage. Cell wall analysis revealed that the extractable matrix (pectic and hemicellulosic) polysaccharides accounted for 30-50% of total sugar content in the fiber elongation stage but less than 3% in the cell wall thickening stage. By contrast, cellulose increased dramatically after the fiber elongation ceased. The amounts of extractable xyloglucans and arabinose- and galactose-containing polymers per seed increased in the early fiber elongation stage and decreased thereafter. The amounts of extractable acidic polymers and non-cellulosic beta-glucans (mainly composed of beta-1,3-glucans) increased in parallel with fiber elongation and then decreased. The molecular masses of extractable non-cellulosic beta-glucans, and arabinose- and galactose-containing polymers decreased during both fiber elongation and cell wall thickening stages. The molecular mass of extractable xyloglucans also decreased during the fiber elongation stage, but this decrease ceased during the cell wall thickening stage. Conversely, the molecular size of acidic polymers in the extractable pectic fraction increased during both stages. Thus, not only the amounts but also the molecular size of the extractable matrix polysaccharides showed substantial changes during cotton fiber development.

  3. Effects of ascorbic acid and sugars on solubility, thermal, and mechanical properties of egg white protein gels.

    Science.gov (United States)

    Mohammadi Nafchi, Abdorreza; Tabatabaei, Ramin H; Pashania, Bita; Rajabi, Hadiseh Z; Karim, A A

    2013-11-01

    The effects of reducing sugars (fructose, glucose, ribose, and arabinose), sucrose, and ascorbic acid were studied on thermo-mechanical properties and crosslinking of egg white proteins (EWP) through Maillard reaction. Sugars (0%, 1%, 5%, and 10%) and ascorbic acid (0%, 0.25%, 0.5%, and 2.5%) were added to EWP solutions. Thermal denaturation and crosslinking of EWP were characterized by differential scanning calorimetry (DSC). Mechanical properties (failure strength, failure strain and Young's modulus) of modified and unmodified EWP gels were evaluated by texture analyzer. Ascorbic acid decreased thermal denaturation temperature of EWP, but the reducing sugars increased the denaturation temperature. DSC thermograms of EWP showed that ascorbic acid exhibited an exothermic transition (≈110 °C) which was attributed to Maillard crosslinking of the protein. The reduction in pH (from 7.21 to ≈6) and protein solubility of egg white protein gel (from ≈70% to ≈10%) provides further evidence of the formation of Maillard cross-linking. Reactive sugars (ribose and arabinose) increased the mechanical properties of EWP gels, whereas ascorbic acid decreased the mechanical properties. Generally, the effect of ascorbic acid was more pronounced than that of various reducing sugars on the thermal and mechanical properties of egg white proteins.

  4. Selective isolation of β-glucan from corn pericarp hemicelluloses by affinity chromatography on cellulose column.

    Science.gov (United States)

    Yoshida, Tomoki; Honda, Yoichi; Tsujimoto, Takashi; Uyama, Hiroshi; Azuma, Jun-ichi

    2014-10-13

    A combination of anion-exchange chromatography and affinity chromatography on a cellulose column was found to be effective for the isolation of β-(1,3;1,4)-glucan (BG) from corn pericarp hemicelluloses (CPHs). CPHs containing 6.6% BG were extracted from corn pericarp with 6M urea-2 wt% NaOH solution and initially fractionated into neutral and acidic parts by anion exchange chromatography to remove acidic arabinoxylan consisting of arabinose (35.6%) and xylose (50.9%). The neutral fraction (yield; 10.1% on the basis of CPHs) consisting of 1.0% arabinose, 10.1% xylose and 80.3% glucose containing 28.4% BG was then applied to a cellulose column of Whatman CF-11. BG could be recovered from the adsorbed fraction on the cellulose column by elution with 2% NaOH in a yield of 2.6% on the basis of CPHs with a purity of 84.7%. The chemical structure of the isolated corn pericarp BG was confirmed by (13)C NMR spectroscopic, methylation and lichenase treatment analyses. The results indicate that the ratios of (1,4)/(1,3) linkage and cellotriosyl/cellotetraosyl segments of the BG were 2.60 and 2.5, respectively.

  5. The isolation and the characterization of two polysaccharides from the branch bark of mulberry (Morus alba L.).

    Science.gov (United States)

    Qiu, Fan; He, Tian-Zhen; Zhang, Yu-Qing

    2016-07-01

    Two water-soluble polysaccharides termed MBBP-1 and MBBP-2 were isolated from the branches of the mulberry tree (Morus alba L.) using hot water extraction and purified on Anion-exchange DEAE52-cellulose and Sephadex G-100 column. MBBP-1 was shown to be composed of rhamnose, xylose, arabinose, mannose, glucose and galactose in the molar ratio of 4.53:2.49:4.38:4.67:17.85:5.88. MBBP-2 was composed of rhamnose, xylose, arabinose, mannose, glucose, galactose and galacturonic acid in the molar ratio of 26.85:13.8:3.14:4.4:6.1:3.19:4.9. Their structural characteristics were further investigated by FI-IR spectroscopy, Smith degradation, methylation analysis and NMR spectroscopy. Based on the data obtained, MBBP-1 had a backbone mainly consisting of (1 → 3)-linked glucose. MBBP-2 had a backbone mainly consisting of (1 → 3)-linked rhamnose and (1 → 2, 4)-linked xylose. Antioxidant assays indicated that antioxidant activities of MBBP-2 were significantly stronger than those of MBBP-1, and this was likely in relation to the different content of 8.2 % galacturonic acid in MBBP-2.

  6. Lectin Activity in Gut Extract of Culex pipiens.

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    Mona Koosha

    2013-06-01

    Full Text Available The role of lectins is important in interaction between pathogens and mosquito vectors. This study was performed to identify agglutinin activities of protein molecules on the midgut of Culex pipiens.Culex pipiens was reared in insectray condition and the midguts of males and females (blood fed and unfed were dissected separately in Tris-HCl buffer. The extracts of midguts were applied for hemagglutinin assay against red blood cells of rabbit, mouse, rat, dog, horse, sheep, guinea pig, cow, human (A, B, AB, O groups. Then, the RBCs with relatively high agglutinin activity were chosen for carbohydrate inhibition assay. D (+ glucose, D (+ galactose, D (+ mannose, D (- fructose, D (- arabinose, L (- fucose, lactose, N-acetyl-D-glucosamine, N-acetyl-D-galactosamine, sialic acid were used to specify carbohydrate binding lectin.The highest agglutinin activities were found against sheep and rabbits RBCs. Sexual diversity of agglutinin activities was observed among midgut extraction of males and females. In addition, variation in agglutinin activity of blood fed and unfed female mosquitoes were detected. The lectin activity was inhibited highly with glucose, galactose, fucose and fructose but less inhibitor activities was observed by arabinose, N-acetyl-D-galactosamine, n-acetyl-d-glucosamine, lactose and mannose.The secretion of hemagglutinins (lectins or lectin-like molecules in the digestive system depends on the type of food in the gut. This suggests that emptying of the gut in preparation for protein rich food probably starts the secretion of hemagglutinins.

  7. Characterization and antioxidative activities of polysaccharide in Chinese angelica and its processed products.

    Science.gov (United States)

    Ji, Peng; Wei, Yanming; Xue, Wenxin; Hua, Yongli; Zhang, Man; Sun, Hongguo; Song, Zhixue; Zhang, Ling; Li, Jinxia; Zhao, Haifu; Zhang, Wenquan

    2014-06-01

    Five polysaccharides from unprocessed Chinese angelica (UCAP), parched one with alcohol (ACAP), soil (SCAP), sesame oil (OCAP) and parched into charred (CCAP) were extracted and purified. Their structures were identified by Fourier transform-infrared spectroscopy (FT-IR), compositions were analyzed by gas chromatography-mass spectrometry (GC-MS) and antioxidative activities were compared by determining MDA contents and SOD activities of liver tissue in mice damaged with CCl4 after gavage. The results showed that the FT-IR spectra of CCAP and OCAP displayed lower transmittance at around 1050cm(-1) in comparison with that of UCAP. Five polysaccharides were all composed of rhamnose, arabinose, mannose, glucose and galactose. In CCAP, ACAP, OCAP and SCAP, the proportions of arabinose were significantly increased in comparison with that of UCAP. The SOD activities in CCAP and SCAP groups were significantly enhanced, and MDA contents in CCAP, OCAP and SCAP groups were significantly decreased as compared with UCAP group. This indicated that processing could change the structure, composition and enhance antioxidative activity of polysaccharide in Chinese angelica, and CCAP possessed the strongest antioxidative activity.

  8. Optimization of extraction, characterization and antioxidant activity of polysaccharides from Brassica rapa L.

    Science.gov (United States)

    Wang, Wei; Wang, Xiaoqing; Ye, Hong; Hu, Bing; Zhou, Li; Jabbar, Saqib; Zeng, Xiaoxiong; Shen, Wenbiao

    2016-01-01

    The root of Brassica rapa L. has been traditionally used as a Uyghur folk medicine to cure cough and asthma by Uyghur nationality in Xinjiang Uygur Autonomous Region of China. In the present study, therefore, extraction optimization, characterization and antioxidant activity in vitro of polysaccharides from the root of B. rapa L. (BRP) were investigated. The optimal extraction conditions with an extraction yield of 21.48 ± 0.41% for crude BRP were obtained as follows: extraction temperature 93°C, extraction time 4.3h and ratio of extraction solvent (water) to raw material 75 mL/g. The crude BRP was purified by chromatographic columns of DEAE-52 cellulose and Sephadex G-100, affording three purified fractions of BRP-1-1, BRP-2-1 and BRP-2-2 with average molecular weight of 1510, 1110 and 838 kDa, respectively. Monosaccharide composition analysis indicated that BRP-1-1 was composed of mannose, rhamnose, glucose, galactose and arabinose, BRP-2-1 was composed of rhamnose, galacturonic acid, galactose and arabinose, and BRP-2-2 was composed of rhamnose and galacturonic acid in a molar ratio of 1.27: 54.92. Furthermore, the crude BRP exhibited relatively higher antioxidant activity in vitro than purified fractions; hence, it could be used as a natural antioxidant in functional foods or medicines.

  9. Purification, characterization and in vitro anticoagulant activity of polysaccharides from Gentiana scabra Bunge roots.

    Science.gov (United States)

    Cai, Weirong; Xu, Huiling; Xie, Liangliang; Sun, Jian; Sun, Taotao; Wu, Xiaoyan; Fu, Qinbao

    2016-04-20

    Three water-soluble polysaccharide fractions (GSP-1, GSP-2 and GSP-3) were obtained from Gentiana scabra Bunge roots by DEAE-Sepharose CL-6B and Sepharose CL-6B column chromatography. Their chemical characterizations were determined by high performance gel permeation chromatography (HPGPC), high performance anion exchange chromatography coupled with pulsed amperometric detection (HPAEC-PAD) and Fourier transform infrared (FT-IR) spectrometer. Moreover, their in vitro anticoagulant activities were evaluated by activated partial thromboplastin time (APTT), thrombin time (TT) and prothrombin time (PT) assays. GSP-1 and GSP-2 were composed of rhamnose, arabinose, galactose, glucose and galacturonic acid, while GSP-3 consisted of rhamnose, arabinose, galactose and galacturonic acid with a weight-average molecular weight of 5.8×10(4)Da. In comparison with the control group (saline), GSP, GSP-1, GSP-2 and GSP-3 could prolong APTT and TT, but not PT. Overall, GSP-3 exhibited potent anticoagulant activity and would be expected to be a potential source of anticoagulant.

  10. Fractionation of corn fiber treated by soaking in aqueous ammonia (SAA) for isolation of hemicellulose B and production of C5 sugars by enzyme hydrolysis.

    Science.gov (United States)

    Nghiem, Nhuan P; Montanti, Justin; Johnston, David B; Drapcho, Caye

    2011-08-01

    A process was developed to fractionate and isolate the hemicellulose B component of corn fiber generated by corn wet milling. The process consisted of pretreatment by soaking in aqueous ammonia followed by enzymatic cellulose hydrolysis, during which the hemicellulose B was solubilized by cleavage into xylo-oligosaccharides and subsequently recovered by precipitation with ethanol. The pretreatment step resulted in high retention of major sugars and improvement of subsequent enzymatic hydrolysis. The recovered hemicellulose B was hydrolyzed by a cocktail of enzymes that consisted of β-glucosidase, pectinase, xylanase, and ferulic acid esterase (FAE). Xylanase alone was ineffective, demonstrating yields of less than 2% of xylose and arabinose. The greatest xylose and arabinose yields, 44% and 53%, respectively, were obtained by the combination of pectinase and FAE. A mass balance accounted for 87% of the initially present glucan, 91% of the xylan, and 90% of the arabinan. The developed process offered a means for production of corn fiber gum as a value-added co-product and C5 sugars, which could be converted to other valuable co-products through fermentation in a corn wet-milling biorefinery.

  11. Feruloyl oligosaccharides stimulate the growth of Bifidobacterium bifidum.

    Science.gov (United States)

    Yuan, Xiaoping; Wang, Jing; Yao, Huiyuan

    2005-08-01

    Insoluble dietary fiber from wheat bran contains some feruloyl groups linked to the arabinose residues in the cell wall arabinoxylan. Treatment of wheat bran insoluble dietary fiber with xylanase from Bacillus subtilis yielded feruloyl oligosacchairdes, which were purified with Amberlite XAD-2. Saponification of the feruloyl oligosaccharides released ferulic acid and arabinoxylan oligosaccharides which consist of arabinose and xylose. The effect of the feruloyl oligosacchairdes on the growth of Bifidobacterium bifidum F-35 was investigated in vitro. The B. bifidum produced acid when cultivated anaerobically in TPY broth with 0.5% feruloyl oligosacchairdes as the carbohydrate source. The biomass yield of the B. bifidum increased with increasing the concentration of feruloyl oligosaccharides in TPY broth. The maximum cell growth was increased by 50% in TPY broth supplemented with 0.1% feruloyl oligosaccharides compared to TPY broth. These results indicated that the growth of B. bifidum F-35 was promoted by the feruloyl oligosaccharides from wheat bran insoluble dietary fiber, and not suppressed by the ferulic acid moiety of them.

  12. Overexpression and export of Vibrio anguillarum metalloprotease in Escherichia coli

    Institute of Scientific and Technical Information of China (English)

    Zhang Fengli; Chi Zhenming; Chen Jixiang; Wu Longfei; Liang Likun

    2007-01-01

    Vibrio anguillarum metalloprotease, an extracellular zinc metalloprotease involved in the virulence mechanism of Vibrio anguillarum, is synthesized from the empA gene as a 611-residue precursor and naturally secreted via Sec secretion pathway in Vibrio anguillarum. In this study, heterologous expression of the empA gene encoding metallopmtease and export of the recombinant metalloprotease in Escherichia coliwere examined. The empA gene was subcloned into pBAD24 with arabinose promoter and sequenced. The sequence encoded a polypeptide(611 amino acids)consisting of four domains: a signal peptide, an Nterminal propeptide, a mature region and a C-terminal propeptide. The empA gene inserted in plasmid pBAD24 was overexpressed in TOP10 strain of E. Coli after arabinose induction. The 36kDa polypeptide of the recombinant metalloprotease as the mature protease was further confirmed by SDS-PAGE and immunoblotting. It was found that recombinant metalloprotease with the EmpA activity and antigenicity wasexported into the periplasm of Escherichia coli cells via Sec translocation pathway, whereas it was secreted into extracellular environments in V. Anguillarum. The results imply that the expression, export and processing mechanism of the protein in E. Coli are similar to those in V. Anguillarum.

  13. Down-regulation of UDP-glucuronic Acid Biosynthesis Leads to Swollen Plant Cell Walls and Severe Developmental Defects Associated with Changes in Pectic Polysaccharides*

    Science.gov (United States)

    Reboul, Rebecca; Geserick, Claudia; Pabst, Martin; Frey, Beat; Wittmann, Doris; Lütz-Meindl, Ursula; Léonard, Renaud; Tenhaken, Raimund

    2011-01-01

    UDP-glucose dehydrogenase (UGD) plays a key role in the nucleotide sugar biosynthetic pathway, as its product UDP-glucuronic acid is the common precursor for arabinose, xylose, galacturonic acid, and apiose residues found in the cell wall. In this study we characterize an Arabidopsis thaliana double mutant ugd2,3 that lacks two of the four UGD isoforms. This mutant was obtained from a cross of ugd2 and ugd3 single mutants, which do not show phenotypical differences compared with the WT. In contrast, ugd2,3 has a strong dwarfed phenotype and often develops seedlings with severe root defects suggesting that the UGD2 and UGD3 isoforms act in concert. Differences in its cell wall composition in comparison to the WT were determined using biochemical methods indicating a significant reduction in arabinose, xylose, apiose, and galacturonic acid residues. Xyloglucan is less substituted with xylose, and pectins have a reduced amount of arabinan side chains. In particular, the amount of the apiose containing side chains A and B of rhamnogalacturonan II is strongly reduced, resulting in a swollen cell wall. The alternative pathway to UDP-glucuronic acid with the key enzyme myo-inositol oxygenase is not up-regulated in ugd2,3. The pathway also does not complement the ugd2,3 mutation, likely because the supply of myo-inositol is limited. Taken together, the presented data underline the importance of UDP GlcA for plant primary cell wall formation. PMID:21949134

  14. Down-regulation of UDP-glucuronic acid biosynthesis leads to swollen plant cell walls and severe developmental defects associated with changes in pectic polysaccharides.

    Science.gov (United States)

    Reboul, Rebecca; Geserick, Claudia; Pabst, Martin; Frey, Beat; Wittmann, Doris; Lütz-Meindl, Ursula; Léonard, Renaud; Tenhaken, Raimund

    2011-11-18

    UDP-glucose dehydrogenase (UGD) plays a key role in the nucleotide sugar biosynthetic pathway, as its product UDP-glucuronic acid is the common precursor for arabinose, xylose, galacturonic acid, and apiose residues found in the cell wall. In this study we characterize an Arabidopsis thaliana double mutant ugd2,3 that lacks two of the four UGD isoforms. This mutant was obtained from a cross of ugd2 and ugd3 single mutants, which do not show phenotypical differences compared with the WT. In contrast, ugd2,3 has a strong dwarfed phenotype and often develops seedlings with severe root defects suggesting that the UGD2 and UGD3 isoforms act in concert. Differences in its cell wall composition in comparison to the WT were determined using biochemical methods indicating a significant reduction in arabinose, xylose, apiose, and galacturonic acid residues. Xyloglucan is less substituted with xylose, and pectins have a reduced amount of arabinan side chains. In particular, the amount of the apiose containing side chains A and B of rhamnogalacturonan II is strongly reduced, resulting in a swollen cell wall. The alternative pathway to UDP-glucuronic acid with the key enzyme myo-inositol oxygenase is not up-regulated in ugd2,3. The pathway also does not complement the ugd2,3 mutation, likely because the supply of myo-inositol is limited. Taken together, the presented data underline the importance of UDP GlcA for plant primary cell wall formation.

  15. 绿茶饮料中茶多糖的构成%The components of tea polysaccarides in soft green tea drink

    Institute of Scientific and Technical Information of China (English)

    屠幼英

    2001-01-01

    The polysaccarides in the soft green tea drink was analyzed by HPLC.The results showed that content of tea polysaccarides was about 3.5% in the total solids.Six kinds of saccarides,i.e.rhamnose,xylose,arabinose,mannose,glucose and galactose were detected.The amounts of arabinose and galactose took up over 80% of the polysaccarides.%用高压液相色谱法(HPLC)测定绿茶饮料中茶叶游离多糖和复合多糖的构成和含量。结果显示,茶多糖总量约为绿茶饮料固形物的3.5%,游离多糖和复合多糖分别为1.9%和1.6%;其中包含了6种糖类:鼠李糖、木糖、阿拉伯糖、葡萄糖、半乳糖和甘露糖;而半乳糖和阿拉伯糖在游离多糖和复合多糖中均占80%以上。

  16. Cj1411c GENE OF CAMPYLOBACTER JEJUNI 11168 ENCODES FOR A CYTOCHROME P450 INVOLVED IN BACTERIAL CAPSULE SUGAR METABOLISM

    Directory of Open Access Journals (Sweden)

    CORCIONIVOSCHI N.

    2007-01-01

    Full Text Available After isolation in 1970s, Campylobacter jejuni become the most commonlyrecognized cause of bacterial gastroenteritis in man. In animals is frequently foundin bovines on ovines. Publishing of the genome sequence of Campylobacter jejuni11168 (Parkhill, 2000 revealed the presence of only one cytochrome P450 in anoperon involved in sugar and cell surface biosynthesis. The gene name is Cj1411c, is1359 bp long and encodes 453 aa. The sequence is strictly conserved inCampylobacter jejuni RM221. Similarities with two cytochrome P450s, one formSilicobacter sp. and one form Poloromonas sp., were identified. These two enzymesare known to be involved in ascorbate and aldarate metabolism. The recombinantconstruct allowed the expression of active P450 enzyme with a 450 nm peak whenbinds CO. The protein was purified in proportion of ~ 70 %. By deleting the P450gene from the Campylobacter jejuni 11168 genome clear changes in cellmorphology were identified cells becoming wider and shorter. The capsular sugarprofile of the NCI strain reveals the presence of arabinose which was not found inthe wild type strain. The arabinose was identified by both High Performance LiquidChromatography (HPLC and Nuclear Magnetic Resonance (NMR.

  17. Centrifugal partition chromatography in a biorefinery context: Separation of monosaccharides from hydrolysed sugar beet pulp.

    Science.gov (United States)

    Ward, David P; Cárdenas-Fernández, Max; Hewitson, Peter; Ignatova, Svetlana; Lye, Gary J

    2015-09-11

    A critical step in the bioprocessing of sustainable biomass feedstocks, such as sugar beet pulp (SBP), is the isolation of the component sugars from the hydrolysed polysaccharides. This facilitates their subsequent conversion into higher value chemicals and pharmaceutical intermediates. Separation methodologies such as centrifugal partition chromatography (CPC) offer an alternative to traditional resin-based chromatographic techniques for multicomponent sugar separations. Highly polar two-phase systems containing ethanol and aqueous ammonium sulphate are examined here for the separation of monosaccharides present in hydrolysed SBP pectin: l-rhamnose, l-arabinose, d-galactose and d-galacturonic acid. Dimethyl sulfoxide (DMSO) was selected as an effective phase system modifier improving monosaccharide separation. The best phase system identified was ethanol:DMSO:aqueous ammonium sulphate (300gL(-1)) (0.8:0.1:1.8, v:v:v) which enabled separation of the SBP monosaccharides by CPC (200mL column) in ascending mode (upper phase as mobile phase) with a mobile phase flow rate of 8mLmin(-1). A mixture containing all four monosaccharides (1.08g total sugars) in the proportions found in hydrolysed SBP was separated into three main fractions; a pure l-rhamnose fraction (>90%), a mixed l-arabinose/d-galactose fraction and a pure d-galacturonic acid fraction (>90%). The separation took less than 2h demonstrating that CPC is a promising technique for the separation of these sugars with potential for application within an integrated, whole crop biorefinery.

  18. Protein enrichment of an Opuntia ficus-indica cladode hydrolysate by cultivation of Candida utilis and Kluyveromyces marxianus

    Science.gov (United States)

    Akanni, Gabriel B; du Preez, James C; Steyn, Laurinda; Kilian, Stephanus G

    2015-01-01

    BACKGROUND The cladodes of Opuntia ficus-indica (prickly pear cactus) have a low protein content; for use as a balanced feed, supplementation with other protein sources is therefore desirable. We investigated protein enrichment by cultivation of the yeasts Candida utilis and Kluyveromyces marxianus in an enzymatic hydrolysate of the cladode biomass. RESULTS Dilute acid pretreatment and enzymatic hydrolysis of sun-dried cladodes resulted in a hydrolysate containing (per litre) 45.5 g glucose, 6.3 g xylose, 9.1 g galactose, 10.8 g arabinose and 9.6 g fructose. Even though K. marxianus had a much higher growth rate and utilized l-arabinose and d-galactose more completely than C. utilis, its biomass yield coefficient was lower due to ethanol and ethyl acetate production despite aerobic cultivation. Yeast cultivation more than doubled the protein content of the hydrolysate, with an essential amino acid profile superior to sorghum and millet grains. CONCLUSIONS This K. marxianus strain was weakly Crabtree positive. Despite its low biomass yield, its performance compared well with C. utilis. This is the first report showing that the protein content and quality of O. ficus-indica cladode biomass could substantially be improved by yeast cultivation, including a comparative evaluation of C. utilis and K. marxianus. © 2014 The Authors. Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. PMID:25371280

  19. Structural analysis of Herbaspirillum seropedicae lipid-A and of two mutants defective to colonize maize roots.

    Science.gov (United States)

    Serrato, Rodrigo V; Balsanelli, Eduardo; Sassaki, Guilherme L; Carlson, Russell W; Muszynski, Artur; Monteiro, Rose A; Pedrosa, Fábio O; Souza, Emanuel M; Iacomini, Marcello

    2012-11-01

    Lipid-A was isolated by mild acid hydrolysis from lipopolysaccharides extracted from cells of Herbaspirillum seropedicae, strain SMR1, and from two mutants deficient in the biosynthesis of rhamnose (rmlB⁻ and rmlC⁻). Structural analyzes were carried out using MALDI-TOF and derivatization by per-O-trimethylsilylation followed by GC-MS in order to determine monosaccharide and fatty acid composition. De-O-acylation was also performed to determine the presence of N-linked fatty acids. Lipid-A from H. seropedicae SMR1 showed a major structure comprising 2-amino-2-deoxy-glucopyranose-(1→6)-2-amino-2-deoxy-glucopyranose phosphorylated at C4' and C1 positions, each carrying a unit of 4-amino-4-deoxy-arabinose. C2 and C2' positions were substituted by amide-linked 3-hydroxy-dodecanoic acids. Both rhamnose-defective mutants showed similar structure for their lipid-A moieties, except for the lack of 4-amino-4-deoxy-arabinose units attached to phosphoryl groups.

  20. Identification and characterization of three Penicillium chrysogenum α-l-arabinofuranosidases (PcABF43B, PcABF51C, and AFQ1) with different specificities toward arabino-oligosaccharides.

    Science.gov (United States)

    Shinozaki, Ayaka; Hosokawa, Sachiko; Nakazawa, Masami; Ueda, Mitsuhiro; Sakamoto, Tatsuji

    2015-06-01

    We previously described four α-l-arabinofuranosidases (ABFs) secreted by Penicillium chrysogenum 31B. Here, we cloned the fifth and sixth genes (Pcabf43B and Pcabf51C) encoding the ABFs PcABF43B and PcABF51C in this strain and overexpressed these genes in Escherichia coli. The deduced amino acid sequences of PcABF43B and PcABF51C were highly similar to putative ABFs belonging to glycoside hydrolase families 43 and 51, respectively. Semiquantitative reverse transcription polymerase chain reaction indicated that both genes were induced by arabinose, arabinitol, arabinan, and arabinoxylan; however, the Pcabf51C gene was constitutively expressed at low levels in P. chrysogenum 31B. PcABF43B had optimal activity at 20°C and pH 5-6, indicating that this enzyme was psychrophilic and had the lowest optimal temperature reported for ABFs. PcABF51C had optimal activity at 45°C and pH 6-7. Both recombinant enzymes showed high activity on arabino-oligosaccharides, but little activity on arabinose-containing polysaccharides, such as l-arabinan. Next, we compared the substrate specificities of PcABF43B, PcABF51C, and AFQ1, a P. chrysogenum ABF that preferentially degraded oligosaccharides over polysaccharides. PcABF43B was found to preferentially hydrolyze (1→3)-linkages in branched arabino-oligosaccharides and released only a small amount of arabinose from linear α-1,5-arabino-oligosaccharides. In contrast, AFQ1 and PcABF51C showed higher activities on linear arabino-oligosaccharides than on branched arabino-oligosaccharides. AFQ1 showed high catalytic efficiencies for α-1,5-l-arabinofuranobiose (α-1,5-Ara2) and α-1,5-l-arabinofuranotriose (α-1,5-Ara3) at the same level. In contrast, intracellular PcABF51C showed much higher catalytic efficiency for α-1,5-Ara2 than for α-1,5-Ara3.

  1. Lipopolysaccharide (LPS) inner-core phosphates are required for complete LPS synthesis and transport to the outer membrane in Pseudomonas aeruginosa PAO1.

    Science.gov (United States)

    Delucia, Angela M; Six, David A; Caughlan, Ruth E; Gee, Patricia; Hunt, Ian; Lam, Joseph S; Dean, Charles R

    2011-01-01

    Gram-negative outer membrane (OM) integrity is maintained in part by Mg(2+) cross-links between phosphates on lipid A and on core sugars of adjacent lipopolysaccharide (LPS) molecules. In contrast to other Gram-negative bacteria, waaP, encoding an inner-core kinase, could not be inactivated in Pseudomonas aeruginosa. To examine this further, expression of the kinases WaaP or WapP/WapQ/PA5006 was placed under the control of the arabinose-regulated pBAD promoter. Growth of these strains was arabinose dependent, confirming that core phosphorylation is essential in P. aeruginosa. Transmission electron micrographs of kinase-depleted cells revealed marked invaginations of the inner membrane. SDS-PAGE of total LPS from WaaP-depleted cells showed accumulation of a fast-migrating band. Mass spectrometry (MS) analysis revealed that LPS from these cells exhibits a unique truncated core consisting of two 3-deoxy-d-manno-octulosonic acids (Kdo), two l-glycero-d-manno-heptoses (Hep), and one hexose but completely devoid of phosphates, indicating that phosphorylation by WaaP is necessary for subsequent core phosphorylations. MS analysis of lipid A from WaaP-depleted cells revealed extensive 4-amino-4-deoxy-l-arabinose modification. OM prepared from these cells by Sarkosyl extraction of total membranes or by sucrose density gradient centrifugation lacked truncated LPS. Instead, truncated LPS was detected in the inner membrane fractions, consistent with impaired transport/assembly of this species into the OM. IMPORTANCE Gram-negative bacteria have an outer membrane (OM) comprised of a phospholipid inner leaflet and a lipopolysaccharide (LPS) outer leaflet. The OM protects cells from toxic molecules and is important for survival during infection. The LPS core kinase gene waaP can be deleted in several Gram-negative bacteria but not in Pseudomonas aeruginosa. We used a controlled-expression system to deplete WaaP directly in P. aeruginosa cells, which halted growth. WaaP depletion

  2. ANALYSIS OF RICIN TOXIN PREPARATIONS FOR CARBOHYDRATE AND FATTY ACID ABUNDANCE AND ISOTOPE RATIO INFORMATION

    Energy Technology Data Exchange (ETDEWEB)

    Wunschel, David S.; Kreuzer-Martin, Helen W.; Antolick, Kathryn C.; Colburn, Heather A.; Moran, James J.; Melville, Angela M.

    2009-12-01

    This report describes method development and preliminary evaluation for analyzing castor samples for signatures of purifying ricin. Ricin purification from the source castor seeds is essentially a problem of protein purification using common biochemical methods. Indications of protein purification will likely manifest themselves as removal of the non-protein fractions of the seed. Two major, non-protein, types of biochemical constituents in the seed are the castor oil and various carbohydrates. The oil comprises roughly half the seed weight while the carbohydrate component comprises roughly half of the remaining “mash” left after oil and hull removal. Different castor oil and carbohydrate components can serve as indicators of specific toxin processing steps. Ricinoleic acid is a relatively unique fatty acid in nature and is the most abundant component of castor oil. The loss of ricinoleic acid indicates a step to remove oil from the seeds. The relative amounts of carbohydrates and carbohydrate-like compounds, including arabinose, xylose, myo-inositol fucose, rhamnose, glucosamine and mannose detected in the sample can also indicate specific processing steps. For instance, the differential loss of arabinose relative to mannose and N-acetyl glucosamine indicates enrichment for the protein fraction of the seed using protein precipitation. The methods developed in this project center on fatty acid and carbohydrate extraction from castor samples followed by derivatization to permit analysis by gas chromatography-mass spectrometry (GC-MS). Method descriptions herein include: the source and preparation of castor materials used for method evaluation, the equipment and description of procedure required for chemical derivatization, and the instrument parameters used in the analysis. Two types of derivatization methods describe analysis of carbohydrates and one procedure for analysis of fatty acids. Two types of GC-MS analysis is included in the method development, one

  3. Capacity for absorption of water-soluble secondary metabolites greater in birds than in rodents.

    Directory of Open Access Journals (Sweden)

    William H Karasov

    Full Text Available Plant secondary metabolites (SMs are pervasive in animal foods and potentially influence feeding behavior, interspecies interactions, and the distribution and abundance of animals. Some of the major classes of naturally occurring SMs in plants include many water-soluble compounds in the molecular size range that could cross the intestinal epithelium via the paracellular space by diffusion or solvent drag. There are differences among species in paracellular permeability. Using Middle Eastern rodent and avian consumers of fruits containing SMs, we tested the hypothesis that avian species would have significantly higher paracellular permeability than rodent species. Permeability in intact animals was assessed using standard pharmacological methodology to measure absorption of two radiolabeled, inert, neutral water-soluble probes that do not interact with intestinal nutrient transporters, L-arabinose (M(r = 150.1 Da and lactulose (M(r = 342.3 Da. We also measured absorption of labeled 3-O-methyl-D-glucose (3OMD-glucose; M(r = 194.2 Da, which is a nonmetabolized analogue of D-glucose that is passively absorbed through the paracellular space but also transported across the enterocyte membranes. Most glucose was absorbed by all species, but arabinose fractional absorption (f was nearly three times higher in birds (1.03±0.17, n = 15 in two species compared to rodents (0.37±0.06, n = 10 in two species (P<0.001. Surprisingly, the apparent rates of absorption in birds of arabinose exceeded those of 3OMD-glucose. Our findings are in agreement with previous work showing that the paracellular pathway is more prominent in birds relative to nonflying mammals, and suggests that birds may be challenged by greater absorption of water-soluble, dietary SMs. The increased expression of the paracellular pathway in birds hints at a tradeoff: the free energy birds gain by absorbing water-soluble nutrients passively may be offset by the metabolic

  4. Regulatory switches for hierarchical use of carbon sources in E. coli

    Directory of Open Access Journals (Sweden)

    Ruth S. Perez-Alfaro

    2014-09-01

    Full Text Available In this work we study the preferential use of carbon sources in the bacterium Escherichia coli. To that end we engineered transcriptional fusions of the reporter gene gfpmut2, downstream of transcription-factor promoters, and analyzed their activity under several conditions. The chosen transcription factors are known to regulate catabolic operons associated to the consumption of alternative sugars. The obtained results indicate the following hierarchical order of sugar preference in this bacterium: glucose > arabinose > sorbitol > galactose. Further dynamical results allowed us to conjecture that this hierarchical behavior might be operated by at least the following three regulatory strategies: 1 the coordinated activation of the corresponding operons by the global regulator catabolic repressor protein (CRP, 2 their asymmetrical responses to specific and unspecific sugars and, 3 the architecture of the associated gene regulatory networks.

  5. Generation of transgenic wheat (Triticum aestivum L.) accumulating heterologous endo-xylanase or ferulic acid esterase in the endosperm

    DEFF Research Database (Denmark)

    Harholt, Jesper; Bach, Inga Christensen; Lind Bouquin, Solveig

    2010-01-01

    . Extensive analysis of the cell walls showed a 10%-15% increase in arabinose to xylose ratio, a 50% increase in the proportion of water-extractable arabinoxylan, and a shift in the MW of the water-extractable arabinoxylan from being mainly larger than 85 kD to being between 2 and 85 kD. Ferulic acid esterase......-expressing grains were also shrivelled, and the seed weight was decreased by 20%-50%. No ferulic acid esterase activity could be detected in wild-type grains whereas ferulic acid esterase activity was detected in transgenic lines. The grain cell walls had 15%-40% increase in water-unextractable arabinoxylan...

  6. Relating Water Deficiency to Berry Texture, Skin Cell Wall Composition, and Expression of Remodeling Genes in Two Vitis vinifera L. Varieties.

    Science.gov (United States)

    Fernandes, J C; Cobb, F; Tracana, S; Costa, G J; Valente, I; Goulao, L F; Amâncio, S

    2015-04-22

    The cell wall (CW) is a dynamic structure that responds to stress. Water shortage (WS) impacts grapevine berry composition and its sensorial quality. In the present work, berry texture, skin CW composition, and expression of remodeling genes were investigated in two V. vinifera varieties, Touriga Nacional (TN) and Trincadeira (TR), under two water regimes, Full Irrigation (FI) and No Irrigation (NI). The global results allowed an evident separation between both varieties and the water treatments. WS resulted in increased anthocyanin contents in both varieties, reduced amounts in cellulose and lignin at maturation, but an increase in arabinose-containing polysaccharides more tightly bound to the CW in TR. In response to WS, the majority of the CW related genes were down-regulated in a variety dependent pattern. The results support the assumption that WS affects grape berries by stiffening the CW through alteration in pectin structure, supporting its involvement in responses to environmental conditions.

  7. Increased mRNA expression of interferon-induced Mx1 and immunomodulation following oral administration of IFN-alpha2b-transformed B. longum to mice.

    Science.gov (United States)

    Yu, Zhijian; Zeng, Zhongming; Huang, Zhen; Lian, Jie; Yang, Jin; Deng, Qiwen; Zeng, Weiseng

    2010-08-01

    We previously constructed an arabinose-inducible recombinant Bifidobacterium longum that could efficiently express secreted IFN-alpha2b in vitro (Deng et al. in Arch Microbiol 191:681-686, 2009). Here, we investigated the influence of oral pBAD-SPIFN-transformed B. longum on immunomodulation and IFN-induced Mx1 gene transcription in mice. We observed enhanced serum and fecal IFN-alpha2b concentrations in mice orally administered recombinant B. longum, suggesting a possible Th1 pattern of induction in the spleen and Peyer's patches. Transcription of the typically IFN-induced antiviral Mx1 gene in the hepatic and intestinal tissues of these mice was also markedly enhanced. In conclusion, oral administration of the recombinant B. longum expressing IFN-alpha2b might play its roles in the immunomodulation of the mice, and the potential clinical value of this bacterium in the treatment of viral infections needs to be further studied.

  8. In vitro fermentation of the polysaccharides from Cyclocarya paliurus leaves by human fecal inoculums.

    Science.gov (United States)

    Min, Fang-Fang; Hu, Jie-Lun; Nie, Shao-Ping; Xie, Jian-Hua; Xie, Ming-Yong

    2014-11-04

    In vitro fermentation of polysaccharide from Cyclocarya paliurus leaves by human fecal inoculums was investigated by determining the changes in contents of neutral and reducing sugar and pH value, consumption of monosaccharide and production of short-chain fatty acids (SCFAs). During fermentation, the content of neutral sugar and reducing sugar decreased as fermentation time increased except that the content of reducing sugar increased within the fermentation time 0.5h. The pH value significantly dropped from 7.2 to 6.04. Remarkably, the greatest yields and the fastest consumption of galacturonic acid were found and the yield of glucose and arabinose were relatively high. The dominant SCFAs, which were acetic acid, propionic acid and n-butyric acid, significantly increased. These results showed that polysaccharide was partly fermented, glycosidic bonds with galacturonic acid being more susceptible to be attacked by gut bacteria and galacturonic acid might be deemed as the main producer of acetic acid.

  9. Optimization of reaction conditions for enzymatic viscosity reduction and hydrolysis of wheat arabinoxylan in an industrial ethanol fermentation residue

    DEFF Research Database (Denmark)

    Sørensen, H.R.; Pedersen, S.; Meyer, Anne Boye Strunge

    2006-01-01

    This study examined enzyme-catalyzed viscosity reduction and evaluated the effects of substrate dry matter concentration on enzymatic degradation of arabinoxylan in a fermentation residue, "vinasse", resulting from industrial ethanol manufacture on wheat. Enzymatic catalysis was accomplished with...... viscosity and that a compromise in the dry matter must be found if enzymatic efficiency must be balanced with monosaccharide yields.......This study examined enzyme-catalyzed viscosity reduction and evaluated the effects of substrate dry matter concentration on enzymatic degradation of arabinoxylan in a fermentation residue, "vinasse", resulting from industrial ethanol manufacture on wheat. Enzymatic catalysis was accomplished...... with increased enzyme dosage and treatment time at pH 5, 50 degrees C, 5 wt % vinasse dry matter. After 24 It of enzymatic treatment, 76-84%, 75-80%, and 43-47%, respectively, of the theoretically maximal arabinose, xylose, and glucose releases were achieved, indicating that the viscosity decrease was a result...

  10. The effect of dietary carbohydrate composition on apparent total tract digestibility, feed mean retention time, nitrogen and water balance in horses

    DEFF Research Database (Denmark)

    Jensen, R B; Austbø, Dag; Knudsen, Knud Erik Bach

    2014-01-01

    obtained by partly substituting mature hay and barley with sugar beet pulp (SBP), a soluble fibre source. The diets investigated were hay only (HAY), hay (85% of dry matter intake (DMI)) and molassed SBP (15% of DMI) (SBP), hay (68% of DMI) and barley (32% of DMI) (BAR), and hay (68% of DMI), barley (26...... (TMRT) of ytterbium-labelled hay, water balance, digestible energy (DE) intake and nitrogen balance were measured. An enzymatic chemical dietary fibre (DF) method was used to get detailed information on the composition and ATTD of the fibre fraction. Inclusion of SBP in the diet increased the ATTD...... of the constituent sugars galactose and arabinose (Pmatter was lower for HAY than the other diets (P=0...

  11. Bacteria engineered for fuel ethanol production: current status

    Energy Technology Data Exchange (ETDEWEB)

    Dien, B.S.; Cotta, M.A. [National Center for Agricultural Utilization Research, Agricultural Research Service, USDA, Peoria, IL (United States); Jeffries, T.W. [Inst. for Microbial and Biochemical Technology, Forest Service, Forest Products Lab., USDA, Madison, WI (United States)

    2004-07-01

    The lack of industrially suitable microorganisms for converting biomass into fuel ethanol has traditionally been cited as a major technical roadblock to developing a bioethanol industry. In the last two decades, numerous microorganisms have been engineered to selectively produce ethanol. Lignocellulosic biomass contains complex carbohydrates that necessitate utilizing microorganisms capable of fermenting sugars not fermentable by brewers' yeast. The most significant of these is xylose. The greatest successes have been in the engineering of gram-negative bacteria: Escherichia coli, Klebsiella oxytoca, and Zymomonas mobilis. E. coli and K. oxytoca are naturally able to use a wide spectrum of sugars, and work has concentrated on engineering these strains to selectively produce ethanol. Z. mobilis produces ethanol at high yields, but ferments only glucose and fructose. Work on this organism has concentrated on introducing pathways for the fermentation of arabinose and xylose. The history of constructing these strains and current progress in refining them are detailed in this review. (orig.)

  12. Sugar Utilization Potential of Micropolyspora Isolated from Extreme Environment

    Directory of Open Access Journals (Sweden)

    A. B. Koli

    2012-01-01

    Full Text Available Problem statement: Waste water of various industries contain large amount of organic compounds which are continuously added in sea via river which causes water pollution. There is need to degrade the organic content to abate water pollution. Approach: To stabilize the organic content in sea water, there was need to search such an organism which was efficient to degrade organic content. We had screened the actinomycetes having potential to degrade organic compounds. Results: Total six isolates of Micropolyspora were obtained, from which all isolates were found to utilize galactose, 50% isolates were able to utilize arabinose, fructose and xylose. 83% of isolates showed mannitol utilization while 67% isolates uses lactose as carbon source and 33% isolates utilizes rhamnose. Conclusion/Recommendation: From the study performed, we conclude that, obtained most of Micropolyspora isolate may be used for the stabilization of organic content and hence in abatement of pollution.

  13. Steam explosion distinctively enhances biomass enzymatic saccharification of cotton stalks by largely reducing cellulose polymerization degree in G. barbadense and G. hirsutum.

    Science.gov (United States)

    Huang, Yu; Wei, Xiaoyang; Zhou, Shiguang; Liu, Mingyong; Tu, Yuanyuan; Li, Ao; Chen, Peng; Wang, Yanting; Zhang, Xuewen; Tai, Hongzhong; Peng, Liangcai; Xia, Tao

    2015-04-01

    In this study, steam explosion pretreatment was performed in cotton stalks, leading to 5-6 folds enhancements on biomass enzymatic saccharification distinctive in Gossypium barbadense and Gossypium hirsutum species. Sequential 1% H2SO4 pretreatment could further increase biomass digestibility of the steam-exploded stalks, and also cause the highest sugar-ethanol conversion rates probably by releasing less inhibitor to yeast fermentation. By comparison, extremely high concentration alkali (16% NaOH) pretreatment with raw stalks resulted in the highest hexoses yields, but it had the lowest sugar-ethanol conversion rates. Characterization of wall polymer features indicated that biomass saccharification was enhanced with steam explosion by largely reducing cellulose DP and extracting hemicelluloses. It also showed that cellulose crystallinity and arabinose substitution degree of xylans were the major factors on biomass digestibility in cotton stalks. Hence, this study has provided the insights into cell wall modification and biomass process technology in cotton stalks and beyond.

  14. Relationship between bran characteristics and bran starch of selected soft wheats grown in Michigan.

    Science.gov (United States)

    Liu, Ya; Ng, Perry K W

    2016-04-15

    The aims of this study were to investigate differences among chosen wheat varieties in their bran starch (the starch adherent to bran particles after a dry milling process) quantity, bran particle size, and milled bran thickness, and to investigate the relationship between bran characteristics and bran starch content. The neutral saccharide profile of the wheat bran was dominated by arabinose, xylose, and glucose, whereas mannose and galactose were present in small amounts. Bran thickness was found to have a positive correlation with bran starch content. Bound ferulic acid to xylose ratio showed positive correlations with percent large bran particles, and negative correlations with bran starch content. Bran characteristics can explain the variation seen in bran starch content and percent large bran particles of various wheat varieties. Bound ferulic acid to xylose ratio and bran thickness could both play roles in the mechanical properties of bran, and therefore change the percent of large bran particles produced during milling.

  15. Feruloyl esterases from Schizophyllum commune to treat food industry side-streams.

    Science.gov (United States)

    Nieter, Annabel; Kelle, Sebastian; Linke, Diana; Berger, Ralf G

    2016-11-01

    Agro-industrial side-streams are abundant and renewable resources of hydroxycinnamic acids with potential applications as antioxidants and preservatives in the food, health, cosmetic, and pharmaceutical industries. Feruloyl esterases (FAEs) from Schizophyllum commune were functionally expressed in Pichia pastoris with extracellular activities of 6000UL(-1). The recombinant enzymes, ScFaeD1 and ScFaeD2, released ferulic acid from destarched wheat bran and sugar beet pectin. Overnight incubation of coffee pulp released caffeic (>60%), ferulic (>80%) and p-coumaric acid (100%) indicating applicability for the valorization of food processing wastes and enhanced biomass degradation. Based on substrate specificity profiling and the release of diferulates from destarched wheat bran, the recombinant FAEs were characterized as type D FAEs. ScFaeD1 and ScFaeD2 preferably hydrolyzed feruloylated saccharides with ferulic acid esterified to the O-5 position of arabinose residues and showed an unprecedented ability to hydrolyze benzoic acid esters.

  16. Modified sugar beet pectin induces apoptosis of colon cancer cells via an interaction with the neutral sugar side-chains.

    Science.gov (United States)

    Maxwell, Ellen G; Colquhoun, Ian J; Chau, Hoa K; Hotchkiss, Arland T; Waldron, Keith W; Morris, Victor J; Belshaw, Nigel J

    2016-01-20

    Pectins extracted from a variety of sources and modified with heat and/or pH have previously been shown to exhibit activity towards several cancer cell lines. However, the structural basis for the anti-cancer activity of modified pectin requires clarification. Sugar beet and citrus pectin extracts have been compared. Pectin extracted from sugar beet pulp only weakly affected the viability of colon cancer cells. Alkali treatment increased the anti-cancer effect of sugar beet pectin via an induction of apoptosis. Alkali treatment decreased the degree of esterification (DE) and increased the ratio of rhamnogalacturonan I (RGI) to homogalacturonan. Low DE per se did not play a significant role in the anti-cancer activity. However, the enzymatic removal of galactose and, to a lesser extent, arabinose from the pectin decreased the effect on cancer cells indicating that the neutral sugar-containing RGI regions are important for pectin bioactivity.

  17. Carbon 13-Metabolic Flux Analysis derived constraint-based metabolic modelling of Clostridium acetobutylicum in stressed chemostat conditions.

    Science.gov (United States)

    Wallenius, Janne; Maaheimo, Hannu; Eerikäinen, Tero

    2016-11-01

    The metabolism of butanol producing bacteria Clostridium acetobutylicum was studied in chemostat with glucose limited conditions, butanol stimulus, and as a reference cultivation. COnstraint-Based Reconstruction and Analysis (COBRA) was applied using additional constraints from (13)C Metabolic Flux Analysis ((13)C-MFA) and experimental measurement results. A model consisting of 451 metabolites and 604 reactions was utilized in flux balance analysis (FBA). The stringency of the flux spaces considering different optimization objectives, i.e. growth rate maximization, ATP maintenance, and NADH/NADPH formation, for flux variance analysis (FVA) was studied in the different modelled conditions. Also a previously uncharacterized exopolysaccharide (EPS) produced by C. acetobutylicum was characterized on monosaccharide level. The major monosaccharide components of the EPS were 40n-% rhamnose, 34n-% glucose, 13n-% mannose, 10n-% galactose, and 2n-% arabinose. The EPS was studied to have butanol adsorbing property, 70(butanol)mg(EPS)g(-1) at 37°C.

  18. Extraction and chemical characterization of rye arabinoxylan and the effect of β-glucan on the mechanical and barrier properties of cast arabinoxylan films

    DEFF Research Database (Denmark)

    Sárossy, Zsuzsa; Tenkanen, Maija; Pitkänen, Leena;

    2013-01-01

    Water-extractable hemicellulose (WEH) fractions, containing approximately 65% arabinoxylans (WE-AX) and 20% mixed-linkage b-glucans were isolated from rye bran. In addition, water-extractable mixedlinkage β-glucans (BG) were isolated from oat bran as a reference material. The β-glucan content...... of the rye hemicellulose isolate was reduced to less than 5% by a selective lichenase treatment. Rye hemicelluloses, WEH and WE-AX had arabinose-to-xylose ratios of 0.54 and 0.57 and weight-average molecular weights (Mw) of 270 000 and 232 000 g/mol respectively. The Mw of BG was higher at 386 000 g...

  19. Extraction, partial characterization and bioactivity of polysaccharides from boat-fruited sterculia seeds.

    Science.gov (United States)

    Ai, Lianzhong; Wu, Jinhong; Che, Na; Wu, Yan; Cui, Steve W

    2012-12-01

    Three polysaccharides (water-soluble (WSP), alkali-soluble (ASP) and insoluble (IMP)) from boat-fruited sterculia seeds were obtained using different extraction methods. Moisture, ash, protein and total carbohydrate content of WSP, ASP and IMP were analyzed. WSP was rich in glucose, rhamnose, arabinose and galactose while small amount of xylose was also detected. The monosaccharide composition as well its relative content for WSP and ASP were similar. The intrinsic viscosity results demonstrated that ASP had much lower intrinsic viscosity than WSP, indicating partial polysaccharides were degraded into low molecular weight polymers during alkaline extraction. The acute anti-inflammatory bioactive results of polysaccharides indicated that WSP demonstrated an inhibitive effect toward acute inflammation.

  20. Molecular and functional characteristics of purified gum from Australian chia seeds.

    Science.gov (United States)

    Timilsena, Yakindra Prasad; Adhikari, Raju; Kasapis, Stefan; Adhikari, Benu

    2016-01-20

    Chia seed gum (CSG) was extracted from the seed coat of Salvia hispanica, purified in the laboratory and its chemical composition and functional properties were investigated. CSG was found to comprise 93.8% carbohydrate consisting of xylose, glucose, arabinose, galactose, glucuronic acid and galacturonic acid as monosaccharide units. The presence of uronic acids was reflected in the anionic behavior of the CSG solution over a wide range of pH (≥ 1.8). The solubility of CSG increased slightly with temperature and pH of the aqueous medium. CSG was able to resist pyrolytic decomposition at temperatures well in excess of 250 °C, and exhibited a high water holding capacity (23 times of its own weight). The surface activity and emulsifying properties of CSG were found to be either superior or comparable to other common gums and industrial polysaccharides indicating the potential of CSG as an effective thickener and stabilizer of processed foods.

  1. Bioethanol production from residual lignocellulosic materials: A review – Part 1

    Directory of Open Access Journals (Sweden)

    CRISTIAN-TEODOR BURUIANA

    2013-08-01

    Full Text Available Lignocellulosic materials (LCM are produced in large quantities and without clear application and their use as raw material for bioethanol production shows economic and ecologic benefits. LCM are composed mainly of three polymers: cellulose made up of glucose units, hemicellulose made up of several sugars (as xylose or arabinose, and lignin made up of phenylpropane units, interconnected in a strong structure. Pretreatment is an important step for bioethanol production from LCM, causing the solubilisation of hemicellulosic fraction (leading to the recovery of hemicellulose-derived saccharides in order to obtain a solid phase enriched in cellulose and more susceptible to enzymatic attack. This study provides a comparative data regarding the chemical composition of various LCM used for bioethanol production, as well as different pretreatment technologies for improving the enzymatic hydrolysis of LCM.

  2. [Gum-like exudate from Laguncularia racemosa (white mangrove) as culture media for fungi].

    Science.gov (United States)

    Mesa, L M; León-Pinto, G

    1993-01-01

    Morphological studies of eight species of fungus: Aspergillus flavus Microsporum canis, Epidermophyton floccosum, Curvularia lunata, Cladosporium carrionii, Natrassia mangífera (Edo. Scytalidium), Sporotrix schenckii y Rhizophus oligosporus, which belong to families Mucedinaceae, Dematiaceae and Mucoraceae have been carried out in support medium based in gum exudate from Laguncularia racemosa (mangle blanco). This native polimer contains galactose, arabinose, rhamnose, uronic acid and proteins. Nitrogen calcium and magnesium are microconstituents of the gum. An economical substrate which contained gum exudate (4%) and agar (1.5%) was used in these studies. The results obtained showed that gum exudate-agar medium (EGA) permits an adequate identification of the studied species, therefore, it is a possible substitute for Sabouraud. It is important to know that the gum exudate is a natural product, economical and easy to obtain.

  3. Non-cellulosic polysaccharides from cotton fibre are differently impacted by textile processing

    DEFF Research Database (Denmark)

    Runavot, Jean-Luc; Guo, Xiaoyuan; Willats, William George Tycho

    2014-01-01

    -cellulosic cotton fibre polysaccharides during different steps of cotton textile processing using GC-MS, HPLC and comprehensive microarray polymer profiling to obtain monosaccharide and polysaccharide amounts and linkage compositions. Additionally, in situ detection was used to obtain information on polysaccharide......Cotton fibre is mainly composed of cellulose, although non-cellulosic polysaccharides play key roles during fibre development and are still present in the harvested fibre. This study aimed at determining the fate of non-cellulosic polysaccharides during cotton textile processing. We analyzed non...... localization and accessibility. We show that pectic and hemicellulosic polysaccharide levels decrease during cotton textile processing and that some processing steps have more impact than others. Pectins and arabinose-containing polysaccharides are strongly impacted by the chemical treatments, with most being...

  4. Extraction, preliminary characterization and evaluation of in vitro antitumor and antioxidant activities of polysaccharides from Mentha piperita.

    Science.gov (United States)

    Liu, Xin; Sun, Zhen-Liang; Jia, Ai-Rong; Shi, Ya-Ping; Li, Rui-Hong; Yang, Pei-Ming

    2014-01-01

    This study describes the extraction, preliminary characterization and evaluation of the in vitro antitumor and antioxidant activities of polysaccharides extracted from Mentha piperita (MPP). The optimal parameters for the extraction of MPP were obtained by Box-Behnken experimental design and response surface methodology (RSM) at the ratio of water to raw material of 20, extraction time of 1.5 h and extraction temperature at 80 °C. Chemical composition analysis showed that MPP was mainly composed of glucuronic acid, galacturonic acid, glucose, galactose and arabinose, and the molecular weight of its two major fractions were estimated to be about 2.843 and 1.139 kDa, respectively. In vitro bioactivity experiments showed that MPP not only inhibited the growth of A549 cells but possessed potent inhibitory action against DNA topoisomerase I (topo I), and an appreciative antioxidant action as well. These results indicate that MPP may be useful for developing safe natural health products.

  5. Production and monomer composition of exopolysaccharides by yogurt starter cultures.

    Science.gov (United States)

    Frengova, G I; Simova, E D; Beshkova, D M; Simov, Z I

    2000-12-01

    As components of starter cultures for Bulgarian yogurt, Streptococcus salivarius subsp. thermophilus and Lactobacillus delbrueckii subsp. bulgaricus revealed extensive exopolysaccharide (EPS) production activity when cultivated in whole cow's milk. The polymer-forming activity of thermophilic streptococci was lower (230-270 mg EPS/L) than that of the lactobacilli (400-540 mg EPS/L). Mixed cultures stimulated EPS production in yogurt manufacture, and a maximum concentration of 720-860 mg EPS/L was recorded after full coagulation of milk. The monomer structure of the exopolysaccharides formed by the yogurt starter cultures principally consists of galactose and glucose (1:1), with small amounts of xylose, arabinose, and/or mannose.

  6. Production of L-sorbitol from L-fructose by Aureobasidium pullulans LP23 isolated from soy sauce mash.

    Science.gov (United States)

    Sasahara, Hiroyuki; Izumori, Ken

    2005-08-01

    A strain LP23 that can convert L-fructose to L-sorbitol was isolated from soy sauce mash and identified as Aureobasidium pullulans. The cells grown on L-arabinose were found to have relatively high L-fructose to L-sorbitol conversion potential. Addition of erythritol to the reaction mixture considerably accelerated the conversion rate of L-fructose to L-sorbitol. During the conversion reaction, erythritol was added to the reaction mixture at 8-h intervals to maintain the concentration of erythritol at 1.0%. The final conversion ratios were 82.8%, 95.3%, 92.4%, and 42.6% using washed cells when the concentrations of L-fructose were 1.0%, 2.0%, 5.0% and 10.0%, respectively. The product from L-fructose was identified as L-sorbitol by HPLC analysis, infrared spectroscopy, optical rotation and melting point measurements.

  7. Formation of exudate droplets by Metarhizium anisopliae and the presence of destruxins.

    Science.gov (United States)

    Hutwimmer, Stefan; Wang, Hui; Strasser, Hermann; Burgstaller, Wolfgang

    2010-01-01

    Nutritional conditions causing droplet exudation by Metarhizium anisopliae var. anisopliae were studied. Exudation in droplets occurred only on media with more than one carbon source and was highly dependent on the ratio of a well metabolized sugar such as trehalose and a nonpreferred sugar, in particular arabinose. Exuded droplets contained destruxin A, B and E in concentrations similar to those on submerged culture on Czapek Dox medium with equivalent C:N ratios but was clearly less than previously reported on standard Czapek Dox or Sabouraud dextrose broth. Destruxins also were found in agar samples from directly below mycelium and from up to 2 cm from the colony edge. Exudates retrieved from different media were proven to have Pr1 protease-related enzyme activity. Additional HPLC analysis indicated that droplets from diverse media did not differ in their sugar and acid content. A hypothesis is presented regarding the trigger for guttation in Metarhizium during growth under these conditions.

  8. Separation of phenolic acids from monosaccharides by low-pressure nanofiltration integrated with laccase pre-treatments

    DEFF Research Database (Denmark)

    Luo, Jianquan; Zeuner, Birgitte; Morthensen, Sofie Thage;

    2015-01-01

    (e.g. dimers and trimers) were mainly responsible for the adsorption fouling. Free laccase treatment was preferred since it was prone to produce large polymeric products while the biocatalytic membrane with immobilized laccase was not suitable as it generated smaller polymers by in-situ product...... monosaccharides (xylose, arabinose, glucose). Four commercial NF membranes (NF270, NP030, NTR7450 and NP010) were evaluated at different pH values and with various laccase pre-treatments (for polymerization of phenolic acids). The results showed that with increasing pH, the retentions of phenolic acids by NF...... removal. Furthermore, the NF membranes with more charge and higher hydrophilicity were more resistant to the irreversible fouling caused by hydrophobic adsorption of phenolic acids and their polymers. This work not only provides fundamental data for removal of phenolic acids from lignocellulosic...

  9. The effect of copper on the content and composition of saccharides in oat plants

    Directory of Open Access Journals (Sweden)

    Maria Ślusarczyk

    2013-12-01

    Full Text Available The relationship between the content and composition of saccharides and the dose and time of application of copper sulphate was studied in different organs and stages of development of oats (Avena sativa L. var. 'Udycz żółty'. The plant material was obtained from pot experiments run on low peat, deficient in copper. Under these conditions, oat plants contained less soluble sugars, hemicelluloses and cellulose than plants receiving a sufficient amount of this element. The differences in the composition of the individual saccharide fractions depended on the dose of copper and time of its application, as well as on the organ and stage of development of the oat plant. In grain of oats grown in copper deficient peat, increased amounts of pentoses (arabinose and xylose were found concomitantly with a lowered glucose content. Attempts to explain the changes in the sugar metabolism under conditions of copper deficiency and the role of this micronutrient in seed formation are presented.

  10. BIODEGRADATION OF REGENERATED CELLULOSE FILMS BY FUNGI

    Institute of Scientific and Technical Information of China (English)

    ZHANG Lina; LIU Haiqing; ZHENG Lianshuang; ZHANG Jiayao; DU Yumin; LIU Weili

    1996-01-01

    The biodegradability of Aspergillus niger (A. niger), Mucor (M-305) and Trichoderma (T-311) strains on regenerated cellulose films in media was investigated. The results showed that T-311 strain isolated from soil adhered on the cellulose film fragments has stronger degradation effect on the cellulose film than A. niger strain. The weights, molecular weights and tensile strengths of the cellulose films in both shake culture and solid media decreased with incubation time, accompanied by producing CO2 and saccharides. HPLC, IR and released CO2 analysis indicated that the biodegradation products of the regenerated cellulose films mainly contain oligosaccharides, cellobiose, glucose, arabinose, erythrose, glycerose,glycerol, ethanal, formaldehyde and organic acid, the end products were CO2 and water.After a month, the films were completely decomposed by fungi in the media at 30℃.

  11. Changes in dominant fermentation type during anaerobic digestion of high-loading glycerol with slight glucose content.

    Science.gov (United States)

    Tokumoto, Hayato; Kashiwagi, Mai

    2012-12-01

    High-loading glycerol containing slight amounts of five different monosaccharides was inoculated with seed sludge obtained from a methane fermentation reactor. The use of different monosaccharides as fermentation promoters resulted in changes in fermentation types; in particular, glucose induced the formation of 1,3-propanediol. After 9 days incubation with glucose, glycerol levels had fallen by 81%, while molar yields of organic acids and 1,3-propanediol (per mole of glycerol degraded) were 0.22 and 0.39, respectively. Other monosaccharides enhanced methane production after 14 days of incubation in the following order: galactose, galacturonic acid, mannose and arabinose. Hydrogen was generated (together with a negligible amount of methane) only in the presence of glucose. When glucose was introduced to a methane-producing reactor (promoted by galacturonic acid), hydrogen production began 5 days later and displaced the methane production after 12 days. These results suggest that glucose catalyzes glycerol degradation, resulting in the production of hydrogen.

  12. The Antituberculosis Drug Ethambutol Selectively Blocks Apical Growth in CMN Group Bacteria

    Science.gov (United States)

    Schubert, Karin; Sieger, Boris; Meyer, Fabian; Giacomelli, Giacomo; Böhm, Kati; Rieblinger, Angela; Lindenthal, Laura; Sachs, Nadja; Wanner, Gerhard

    2017-01-01

    ABSTRACT Members of the genus Mycobacterium are the most prevalent cause of infectious diseases. Mycobacteria have a complex cell envelope containing a peptidoglycan layer and an additional arabinogalactan polymer to which a mycolic acid bilayer is linked; this complex, multilayered cell wall composition (mAGP) is conserved among all CMN group bacteria. The arabinogalactan and mycolic acid synthesis pathways constitute effective drug targets for tuberculosis treatment. Ethambutol (EMB), a classical antituberculosis drug, inhibits the synthesis of the arabinose polymer. Although EMB acts bacteriostatically, its underlying molecular mechanism remains unclear. Here, we used Corynebacterium glutamicum and Mycobacterium phlei as model organisms to study the effects of EMB at the single-cell level. Our results demonstrate that EMB specifically blocks apical cell wall synthesis, but not cell division, explaining the bacteriostatic effect of EMB. Furthermore, the data suggest that members of the family Corynebacterineae have two dedicated machineries for cell elongation (elongasome) and cytokinesis (divisome). PMID:28174310

  13. The importance of the Abn2 calcium cluster in the endo-1,5-arabinanase activity from Bacillus subtilis.

    Science.gov (United States)

    McVey, C E; Ferreira, M J; Correia, B; Lahiri, S; de Sanctis, D; Carrondo, Maria Arménia; Lindley, P F; de Sá Nogueira, Isabel; Soares, Cláudio Manuel; Bento, Isabel

    2014-06-01

    Arabinanase is a glycosyl hydrolase that is able to cleave the glycosidic bonds of α-1,5-L-arabinan, releasing arabino-oligosaccharides and L-arabinose. The enzyme has two domains, an N-terminal catalytic domain with a characteristic β-propeller fold and a C-terminal domain whose function is unknown. A calcium ion, located near the catalytic site, serves to stabilize the N-terminal domain, but it has also been proposed to play a key role in the enzyme mechanism. The present work describes the structure of an inactive mutant of the wild-type enzyme (H318Q) and in which the calcium ion has been adventitiously replaced by nickel. These structural studies, together with functional and modelling studies, clearly support the role of the calcium ion in the overall reaction mechanism.

  14. Antioxidant property of water-soluble polysaccharides from Poria cocos Wolf using different extraction methods.

    Science.gov (United States)

    Wang, Nani; Zhang, Yang; Wang, Xuping; Huang, Xiaowen; Fei, Ying; Yu, Yong; Shou, Dan

    2016-02-01

    Poria cocos Wolf is a popular traditional medicinal plant that has invigorating activity. Water-soluble polysaccharides (PCPs) are its main active components. In this study, four different methods were used to extract PCPs, which include hot water extraction (PCP-H), ultrasonic-assisted extraction (PCP-U), enzyme-assisted extraction (PCP-E) and microwave-assisted extraction (PCP-M). Their chemical compositions and structure characterizations were compared. In vitro antioxidant activities were studied on the basis of DPPH radical, hydroxyl radical, reducing power and metal chelating ability. The results showed that PCPs were composed of mannose, glucose, galactose, and arabinose, and had typical IR spectra characteristics of polysaccharides. Compared with other PCPs, PCP-M had lower neutral sugar content, higher mannose content and higher uronic acid content. The molecular weight were determined as PCP-Ecocos Wolf.

  15. Enzymatic Hydrolysis of Wheat Arabinoxylan by a Recombinant "Minimal" Enzyme Cocktail Containing beta-Xylosidase and Novel endo-1,4-beta-Xylanase and alpha-L-Arabinofuranosidase Activities

    DEFF Research Database (Denmark)

    Sørensen, Hanne R.; Pedersen, Sven; Jørgensen, Christel T.;

    2007-01-01

    24 h at pH 5, 50 degrees C. A 10%:40%:50% mixture of Abf II, Abf III, and beta-xyl released 56 mg of arabinose and 91 mg of xylose per gram of vinasse dry matter after 24 h at pH 5, 50 degrees C. The optimal dosages of the "minimal" enzyme cocktails were determined to be 0.4, 0.3, and 0.2 g enzyme......This study describes the identification of the key enzyme activities required in a "minimal" enzyme cocktail able to catalyze hydrolysis of water-soluble and water-insoluble wheat arabinoxylan and whole vinasse, a fermentation effluent resulting from industrial ethanol manufacture from wheat...

  16. Characterization of polysaccharides extracted from spent coffee grounds by alkali pretreatment.

    Science.gov (United States)

    Ballesteros, Lina F; Cerqueira, Miguel A; Teixeira, José A; Mussatto, Solange I

    2015-01-01

    Spent coffee grounds (SCG), obtained during the processing of coffee powder with hot water to make soluble coffee, are the main coffee industry residues and retain approximately seventy percent of the polysaccharides present in the roasted coffee beans. The purpose of this study was to extract polysaccharides from SCG by using an alkali pretreatment with sodium hydroxide at 25°C, and determine the chemical composition, as well as the antioxidant and antimicrobial properties of the extracted polysaccharides. Galactose (60.27%mol) was the dominant sugar in the recovered polysaccharides, followed by arabinose (19.93%mol), glucose (15.37%mol) and mannose (4.43%mol). SCG polysaccharides were thermostable, and presented a typical carbohydrate pattern. Additionally, they showed good antioxidant activity through different methods and presented high antimicrobial percent inhibition against Phoma violacea and Cladosporium cladosporioides (41.27% and 54.60%, respectively). These findings allow identifying possible applications for these polysaccharides in the food industry.

  17. Benzothiazinones kill Mycobacterium tuberculosis by blocking arabinan synthesis.

    Science.gov (United States)

    Makarov, Vadim; Manina, Giulia; Mikusova, Katarina; Möllmann, Ute; Ryabova, Olga; Saint-Joanis, Brigitte; Dhar, Neeraj; Pasca, Maria Rosalia; Buroni, Silvia; Lucarelli, Anna Paola; Milano, Anna; De Rossi, Edda; Belanova, Martina; Bobovska, Adela; Dianiskova, Petronela; Kordulakova, Jana; Sala, Claudia; Fullam, Elizabeth; Schneider, Patricia; McKinney, John D; Brodin, Priscille; Christophe, Thierry; Waddell, Simon; Butcher, Philip; Albrethsen, Jakob; Rosenkrands, Ida; Brosch, Roland; Nandi, Vrinda; Bharath, Sowmya; Gaonkar, Sheshagiri; Shandil, Radha K; Balasubramanian, Venkataraman; Balganesh, Tanjore; Tyagi, Sandeep; Grosset, Jacques; Riccardi, Giovanna; Cole, Stewart T

    2009-05-08

    New drugs are required to counter the tuberculosis (TB) pandemic. Here, we describe the synthesis and characterization of 1,3-benzothiazin-4-ones (BTZs), a new class of antimycobacterial agents that kill Mycobacterium tuberculosis in vitro, ex vivo, and in mouse models of TB. Using genetics and biochemistry, we identified the enzyme decaprenylphosphoryl-beta-d-ribose 2'-epimerase as a major BTZ target. Inhibition of this enzymatic activity abolishes the formation of decaprenylphosphoryl arabinose, a key precursor that is required for the synthesis of the cell-wall arabinans, thus provoking cell lysis and bacterial death. The most advanced compound, BTZ043, is a candidate for inclusion in combination therapies for both drug-sensitive and extensively drug-resistant TB.

  18. Extraction and characterization of Foeniculum vulgare pectins and their use for preparing biopolymer films in the presence of phaseolin protein.

    Science.gov (United States)

    Giosafatto, Concetta V L; Mariniello, Loredana; Ring, Steve

    2007-02-21

    Pectins from Foeniculum vulgare were extracted under acidic conditions. The obtained pectins were mainly composed of uronic acid but also contained traces of rhamnose, galactose, and arabinose. Extracted pectins were used as a carbohydrate source to prepare biopolymer films in the absence and in the presence of phaseolin protein. The swelling characteristics of the films were examined as a function of ionic strength, pH, and the applied osmotic stress. The swelling behavior was dominated by a Donnan-type effect, which decreases with increasing ionic strength and counterion valency. In all cases the swelling of films containing phaseolin was reduced, suggesting a network formation between protein and pectins. Mechanical property studies have also estimated the validity of the obtained novel biopolymer films in terms of mechanical resistance.

  19. Characterization and biological activities of a novel polysaccharide isolated from raspberry (Rubus idaeus L.) fruits.

    Science.gov (United States)

    Yu, Zeyuan; Liu, Lu; Xu, Yaqin; Wang, Libo; Teng, Xin; Li, Xingguo; Dai, Jing

    2015-11-05

    A water-soluble polysaccharide namely RCP-II from raspberry fruits was obtained by complex enzyme method followed by successive purification using macroporous resin D4020 and Sephadex G-100 columns. RCP-II was an acidic heteropolysaccharide and the characteristic structure of polysaccharide was determined. The carbohydrate of RCP-II was composed with galacturonic acid, rhamnose, arabinose, xylose, glucose and galactose in a molar ratio of 1.00:0.55:1.19:0.52:0.44:1.90 and the average molecular weight was estimated to be 4013 Da, based on dextran standards. RCP-II presented high scavenging activity toward DPPH•, HO•, O2(•-) in a concentration-dependent manner. The determination of the inhibitory activity on protein glycation showed that in 14 days of incubation the inhibitory ability of RCP-II was more effective on the development of non-enzymatic glycation reaction at early phase than that at the following two phases.

  20. The composition of cell wall skeleton and outermost lipids of Mycobacterium vaccae is modified by ethambutol treatment.

    Science.gov (United States)

    Rumijowska-Galewicz, Anna; Korycka-Machała, Małgorzata; Lisowska, Katarzyna; Dziadek, Jarosław

    2008-01-01

    Ethambutol (EMB) is a first line drug in tuberculosis treatment inhibiting the biosynthesis of arabinogalactan, which is a component of the mycobacterial cell wall. The growth of Mycobacterium vaccae cells in the presence of EMB increases cell wall permeability, which was monitored by beta-sitosterol biotransformation. GC/MS and GLC/MS (gas chromatography/mass spectrometry) analysis revealed dramatic changes in the content of covalently bound mycolic acids and in molar ratio galactose (Gal) to arabinose (Ara) in the cell envelopes of EMB-treated cells. The detected variations in the compositions of fatty acids indicate that both the cell wall skeleton and outer layer (free lipids) are decomposed due to EMB treatment.

  1. G-lignin and hemicellulosic monosaccharides distinctively affect biomass digestibility in rapeseed.

    Science.gov (United States)

    Pei, Yanjie; Li, Yuyang; Zhang, Youbing; Yu, Changbing; Fu, Tingdong; Zou, Jun; Tu, Yuanyuan; Peng, Liangcai; Chen, Peng

    2016-03-01

    In this study, total 19 straw samples from four Brassica species were determined with a diverse cell wall composition and varied biomass enzymatic digestibility under sulfuric acid or lime pretreatment. Correlation analysis was then performed to detect effects of cell wall compositions and wall polymer features (cellulose crystallinity, hemicellulosic monosaccharides and lignin monomers) on rapeseeds biomass digestibility. As a result, coniferyl alcohol (G-lignin) showed a strongly negative effect on biomass saccharification, whereas hemicellulosic monosaccharides (fucose, galactose, arabinose and rhamnose) were positive factors on lignocellulose digestions. Notably, chemical analyses of four typical pairs of samples indicated that hemicellulosic monosaccharides and G-lignin may coordinately influence biomass digestibility in rapeseeds. In addition, Brassica napus with lower lignin content exhibited more efficiency on both biomass enzymatic saccharification and ethanol production, compared with Brassica junjea. Hence, this study has at first time provided a genetic strategy on cell wall modification towards bioenergy rapeseed breeding.

  2. 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...

  3. Structure-specificity relationships in Abp, a GH27 β-L-arabinopyranosidase from Geobacillus stearothermophilus T6.

    Science.gov (United States)

    Lansky, Shifra; Salama, Rachel; Solomon, Hodaya V; Feinberg, Hadar; Belrhali, Hassan; Shoham, Yuval; Shoham, Gil

    2014-11-01

    L-Arabinose sugar residues are relatively abundant in plants and are found mainly in arabinan polysaccharides and in other arabinose-containing polysaccharides such as arabinoxylans and pectic arabinogalactans. The majority of the arabinose units in plants are present in the furanose form and only a small fraction of them are present in the pyranose form. The L-arabinan-utilization system in Geobacillus stearothermophilus T6, a Gram-positive thermophilic soil bacterium, has recently been characterized, and one of the key enzymes was found to be an intracellular β-L-arabinopyranosidase (Abp). Abp, a GH27 enzyme, was shown to remove β-L-arabinopyranose residues from synthetic substrates and from the native substrates sugar beet arabinan and larch arabinogalactan. The Abp monomer is made up of 448 amino acids, and based on sequence homology it was suggested that Asp197 is the catalytic nucleophile and Asp255 is the catalytic acid/base. In the current study, the detailed three-dimensional structure of wild-type Abp (at 2.28 Å resolution) and its catalytic mutant Abp-D197A with (at 2.20 Å resolution) and without (at 2.30 Å resolution) a bound L-arabinose product are reported as determined by X-ray crystallography. These structures demonstrate that the three-dimensional structure of the Abp monomer correlates with the general fold observed for GH27 proteins, consisting of two main domains: an N-terminal TIM-barrel domain and a C-terminal all-β domain. The two catalytic residues are located in the TIM-barrel domain, such that their carboxylic functional groups are about 5.9 Å from each other, consistent with a retaining mechanism. An isoleucine residue (Ile67) located at a key position in the active site is shown to play a critical role in the substrate specificity of Abp, providing a structural basis for the high preference of the enzyme towards arabinopyranoside over galactopyranoside substrates. The crystal structure demonstrates that Abp is a tetramer

  4. Role of major wine constituents in the foam properties of white and rosé sparkling wines.

    Science.gov (United States)

    Martínez-Lapuente, Leticia; Guadalupe, Zenaida; Ayestarán, Belén; Pérez-Magariño, Silvia

    2015-05-01

    The chemical composition of sparkling wines is directly related to their foam quality, but the compounds responsible are not yet completely established. This work aims at identifying the contribution of the different wine compounds to the foaming properties of white and rosé sparkling wines. Our results demonstrated the positive contribution of anthocyanins and amino acids to the foamability parameters HM (maximum height reached by foam after CO2 injection) and HS (foam stability height during CO2 injection), and the negative contribution of proanthocyanidins. Mannoproteins and polysaccharides rich in arabinose and galactose (PRAG) were poor foam formers but good foam stabilizers. The different forms of malvidin showed the highest influence on the HM and HS parameters, followed by amino acid compounds, mainly β-alanine. The model to explain foam stability was only predicted by polysaccharides from grapes, concretely PRAG. To our knowledge, this is the first time these correlations in sparkling wines have been described.

  5. Opuntia dillenii (Ker-Gawl) Haw cladode mucilage: Physico-chemical, rheological and functional behavior.

    Science.gov (United States)

    Kalegowda, Pavithra; Chauhan, Attar Singh; Nanjaraj Urs, Shashirekha Mysore

    2017-02-10

    The yield of mucilage extracted from cladodes of Opuntia dillenii (Ker-Gawl) Haw in aqueous medium was 6.2%. The neutral sugar comprised of arabinose (38.80%), galactose (33.00%), rhamnose (15.70%), xylose (5.10%), and glucose (5.10%). The mucilage showed pseudo plastic behavior with good swelling index (20%), water holding capacity (g water/g dry sample; 4±0.10) and micrometric properties. In addition, mucilage presented intrinsic viscosity of 3.7 dL/g with average molecular weight of 1.9×10(3)kDa. The FTIR and NMR spectra of extracted mucilage showed characteristic polysaccharide nature. Further, the mucilage exhibited anti-obesity property through lipase inhibition. These findings could highlight that isolated mucilage could be exploited as an additive in food and pharmaceutical sector.

  6. Alkaline Hydrolysis Kinetics Modeling of Bagasse Pentosan Dissolution

    Directory of Open Access Journals (Sweden)

    Yuxin Liu

    2013-11-01

    Full Text Available The main pentosan components of sugarcane bagasse, which can be subjected to alkaline hydrolysis, are xylose, arabinose, glucose, and galactose. The pentosan reaction mechanism was considered for alkali-treated bagasse with variation of temperature and time. The kinetics of pentosan degradation were studied concurrently at temperatures of 50 °C, 70 °C, and 90 °C, with a solid-liquid mass ratio of 1:15, a stirring speed of 500 revolutions/min, and different holding times for bagasse alkali pre-extraction. With respect to residual pentosan content and the losses of raw material, the hydrolysis rates of alkali pre-extraction and pentosan degradation reactions of bagasse all followed pseudo-first-order kinetic models. Finally, the main degradation activation energy was determined to be 20.86 KJ/mol, and the residual degradation activation energy was 28.75 KJ/mol according to the Arrhenius equation.

  7. Effect of soil sieving on respiration induced by low-molecular-weight substrates

    Science.gov (United States)

    Datta, Rahul; Vranová, Valerie; Pavelka, Marian; Rejšek, Klement; Formánek, Pavel

    2014-03-01

    The mesh size of sieves has a significant impact upon soil disturbance, affecting pore structure, fungal hyphae, proportion of fungi to bacteria, and organic matter fractions. The effects are dependent upon soil type and plant coverage. Sieving through a 2 mm mesh increases mineralization of exogenously supplied carbohydrates and phenolics compared to a 5 mm mesh and the effect is significant (p<0.05), especially in organic horizons, due to increased microbial metabolism and alteration of other soil properties. Finer mesh size particularly increases arabinose, mannose, galactose, ferulic and pthalic acid metabolism, whereas maltose mineralization is less affected. Sieving through a 5 mm mesh size is suggested for all type of experiments where enhanced mineralization of low-molecular-weight organic compounds needs to be minimalized.

  8. The type of carbohydrates specifically selects microbial community structures and fermentation patterns.

    Science.gov (United States)

    Chatellard, Lucile; Trably, Eric; Carrère, Hélène

    2016-12-01

    The impact on dark fermentation of seven carbohydrates as model substrates of lignocellulosic fractions (glucose, cellobiose, microcrystalline cellulose, arabinose, xylose, xylan and wheat straw) was investigated. Metabolic patterns and bacterial communities were characterized at the end of batch tests inoculated with manure digestate. It was found that hydrogen production was linked to the sugar type (pentose or hexose) and the degree of polymerisation. Hexoses produced less hydrogen, with a specific selection of lactate-producing bacterial community structures. Maximal hydrogen production was five times higher on pentose-based substrates, with specific bacterial community structures producing acetate and butyrate as main metabolites. Low hydrogen amounts accumulated from complex sugars (cellulose, xylan and wheat straw). A relatively high proportion of the reads was affiliated to Ruminococcaceae suggesting an efficient hydrolytic activity. Knowing that the bacterial community structure is very specific to a particular substrate offers new possibilities to design more efficient H2-producing biological systems.

  9. Statistical model semiquantitatively approximates arabinoxylooligosaccharides' structural diversity

    DEFF Research Database (Denmark)

    Dotsenko, Gleb; Nielsen, Michael Krogsgaard; Lange, Lene

    2016-01-01

    A statistical model describing the random distribution of substituted xylopyranosyl residues in arabinoxylooligosaccharides is suggested and compared with existing experimental data. Structural diversity of arabinoxylooligosaccharides of various length, originating from different arabinoxylans...... (wheat flour arabinoxylan (arabinose/xylose, A/X = 0.47); grass arabinoxylan (A/X = 0.24); wheat straw arabinoxylan (A/X = 0.15); and hydrothermally pretreated wheat straw arabinoxylan (A/X = 0.05)), is semiquantitatively approximated using the proposed model. The suggested approach can be applied...... not only for prediction and quantification of arabinoxylooligosaccharides' structural diversity, but also for estimate of yield and selection of the optimal source of arabinoxylan for production of arabinoxylooligosaccharides with desired structural features....

  10. Ribose and related sugars from ultraviolet irradiation of interstellar ice analogs

    Science.gov (United States)

    Meinert, Cornelia; Myrgorodska, Iuliia; de Marcellus, Pierre; Buhse, Thomas; Nahon, Laurent; Hoffmann, Søren V.; d'Hendecourt, Louis Le Sergeant; Meierhenrich, Uwe J.

    2016-04-01

    Ribose is the central molecular subunit in RNA, but the prebiotic origin of ribose remains unknown. We observed the formation of substantial quantities of ribose and a diversity of structurally related sugar molecules such as arabinose, xylose, and lyxose in the room-temperature organic residues of photo-processed interstellar ice analogs initially composed of H2O, CH3OH, and NH3. Our results suggest that the generation of numerous sugar molecules, including the aldopentose ribose, may be possible from photochemical and thermal treatment of cosmic ices in the late stages of the solar nebula. Our detection of ribose provides plausible insights into the chemical processes that could lead to formation of biologically relevant molecules in suitable planetary environments.

  11. Altered amino acid excretion in children with autism.

    Science.gov (United States)

    Evans, Craig; Dunstan, R Hugh; Rothkirch, Tony; Roberts, Tim K; Reichelt, Karl L; Cosford, Robyn; Deed, Gary; Ellis, Libby B; Sparkes, Diane L

    2008-02-01

    Autism is a complex and life-long behavioural disorder of unknown aetiology. Recent reports have indicated the involvement of digestive tract dysfunction and possible complications from inadequate nutrition. In this study, 34 autistic children (12 untreated and 22 receiving therapeutic treatments related to digestive function and nutritional uptake) and 29 control subjects (all 5-15 years of age) were investigated to determine whether there were any anomalies in the urinary excretion of amino acids, glucose, sucrose, arabinose and tartaric acid using GC/FID and GC/MS analysis techniques. Significantly lower relative urinary levels of essential amino acids were revealed for both the untreated (mean +/- SEM, 32.53 +/- 3.09%) and treated (31.98 +/- 2.87%) autistic children compared with the controls (37.87 +/- 1.50%). There were no significant differences in measured excretions of sugars or tartaric acid. It was concluded that the untreated autistic children had evidence of altered metabolic homeostasis.

  12. An Acidic Polysaccharide from Tribulus terrestris

    Institute of Scientific and Technical Information of China (English)

    HaiShengCHEN; WingNangLEUNG; 等

    2002-01-01

    An aqueous acidic polysaccharide, named rhamnogalacturonan (designated as TIP-D2) was isolated from Tribulus terrestris L by means of DEAE-cellulose chromatography and gel filtration. The molecular mass of TTP-D2 was estimated to be 26 KDa by gel filtration.TTP-D2 is composed of galacturonic acid, rhamnose, arabinose, galactose,fucose,mannose,xylose and glucose in a ratio of 71.4:13.5:5.6:4.9:3.1:1.9:1.9:1.0. The main chain structure of TTP-D2 was elucidated as an acidic hetero-polysaccaride with the connection of α-(1-4) galacturonic acid with α-(1-3) rhamnose by GC analysis of partially hydrolyzed products and determination of 1H,13C-NMR spectra.

  13. An Acidic Polysaccharide from Tribulus terrestris

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    An aqucous acidic polysaccharide, named rhamnogalacturonan (designated as TTP-D2)was isolated from Tribulus terrestris L by means of DEAE-cellulose chromatography and gel filtration. The molecular mass of TTP-D2 was estimated to be 26 KDa by gel filtration. TTP-D2 is composed of galacturonic acid, rhamnose, arabinose, galactose, fucose, mannosc, xylose and glucose in a ratio of 71.4: 13.5: 5.6: 4.9: 3.1: 1.9: 1.9: 1.0. The main chain structure of TTP-D2 was elucidated as an acidic hetero-polysaccharidc with the connection of α-(l-4) galacturonic acid with α-(1-3) rhamnose by GC analysis of partially hydrolyzed products and the determination of 1H, 13C-NMR spectra.

  14. Measurements of particulate sugars at urban and forested suburban sites

    Science.gov (United States)

    Tominaga, Sae; Matsumoto, Kiyoshi; Kaneyasu, Naoki; Shigihara, Ado; Katono, Koichi; Igawa, Manabu

    2011-04-01

    Neutral sugars (arabinose, fucose, galactose, glucose, mannose, rhamnose, and xylose) in fine and coarse aerosols were measured at urban and forested suburban sites in Japan. The most dominant compound in the sugar group was glucose at both sites. Size partitioning of the sugars generally showed dominance in the fine mode range but shifted toward the coarse mode range in summer. Seasonal trends in the sugar concentrations in the fine and coarse mode ranges were opposite: higher concentrations of fine mode sugars were found in winter, although coarse mode sugars increased in summer. Fine mode glucose consisted dominantly of the combined form, whereas free glucose increased in the coarse mode range. Although the sources of the sugars in the aerosols remain largely uncertain, primary biogenic particles can be considered as candidates of main sources of the sugars in both coarse and fine mode ranges.

  15. Effect of soil carbohydrates on nutrient availability in natural forests and cultivated lands in Sri Lanka

    Science.gov (United States)

    Ratnayake, R. R.; Seneviratne, G.; Kulasooriya, S. A.

    2013-05-01

    Carbohydrates supply carbon sources for microbial activities that contribute to mineral nutrient production in soil. Their role on soil nutrient availability has not yet been properly elucidated. This was studied in forests and cultivated lands in Sri Lanka. Soil organic matter (SOM) fractions affecting carbohydrate availability were also determined. Soil litter contributed to sugars of plant origin (SPO) in croplands. The negative relationship found between clay bound organic matter (CBO) and glucose indicates higher SOM fixation in clay that lower its availability in cultivated lands. In forests, negative relationships between litter and sugars of microbial origin (SMO) showed that litter fuelled microbes to produce sugars. Fucose and glucose increased the availability of Cu, Zn and Mn in forests. Xylose increased Ca availability in cultivated lands. Arabinose, the main carbon source of soil respiration reduced the P availability. This study showed soil carbohydrates and their relationships with mineral nutrients could provide vital information on the availability of limiting nutrients in tropical ecosystems.

  16. Draft genome sequence and detailed analysis of Pantoea eucrina strain Russ and implication for opportunistic pathogenesis

    Directory of Open Access Journals (Sweden)

    Farzaneh Moghadam

    2016-12-01

    Full Text Available The genus Pantoea is a predominant member of host-associated microbiome. We here report on the genomic analysis of Pantoea eucrina strain Russ that was isolated from a trashcan at Oklahoma State University, Stillwater, OK. The draft genome of Pantoea eucrina strain Russ consists of 3,939,877 bp of DNA with 3704 protein-coding genes and 134 RNA genes. This is the first report of a genome sequence of a member of Pantoea eucrina. Genomic analysis revealed metabolic versatility with genes involved in the metabolism and transport of all amino acids as well as glucose, fructose, mannose, xylose, arabinose and galactose, suggesting the organism is a versatile heterotroph. The genome also encodes an extensive secretory machinery including types I, II, III, IV, and Vb secretion systems, and several genes for pili production including the new usher/chaperone system (pfam 05,229. The implications of these systems for opportunistic pathogenesis are discussed.

  17. Changes in the arabinoxylan fraction of wheat grain during alcohol production.

    Science.gov (United States)

    Kosik, Ondrej; Powers, Stephen J; Chatzifragkou, Afroditi; Prabhakumari, Parvathy Chandran; Charalampopoulos, Dimitris; Hess, Linde; Brosnan, James; Shewry, Peter R; Lovegrove, Alison

    2017-04-15

    Laboratory produced DDGS samples were compared with commercial samples from a distillery and a biofuel plant. Changes in structure, solubility and content of arabinoxylan (AX) was determined. The distillation process results in a relative increase of AX content compared to the starting material. The heating and drying processes involved in the production of DDGS lead to an increased solubility and viscosity of water-extractable AX. Production of DDGS results in structural changes to the AX. There is a decrease in 2- and 3-linked arabinose oligosaccharides, that contributes to around a 50% reduction in arabinosylation in DDGS compared with the starting grains. The current study shows that laboratory-scale DDGS provide an accurate representation of the commercial scale and that the AX composition of DDGS is consistently uniform irrespective of starting material. The uniformity of DDGS and thin stillage makes them a good potential source of AX for production of prebiotics or other novel products.

  18. Properties and extraction of pectin-enriched materials from sugar beet pulp by ultrasonic-assisted treatment combined with subcritical water.

    Science.gov (United States)

    Chen, Hai-ming; Fu, Xiong; Luo, Zhi-gang

    2015-02-01

    Pectin-enriched material (PEM) was extracted from sugar beet pulp using subcritical water combined with ultrasonic-assisted treatment. Optimisation of the reaction parameters for maximum extraction yield of PEM was carried out using response surface methodology. Optimum modification conditions were as follows: liquid/solid ratio 44.03, extraction temperature 120.72°C, extraction time 30.49min and extraction pressure 10.70MPa. Under optimal conditions, the maximum yield of PEM was 24.63%. The composition of the PEM was determined. The data showed that the contents of galacturonic acid and arabinose were 59.12% and 21.66%, respectively. The flow behaviours were investigated by a rheometer. The effects of PEM on the pasting and thermal properties of maize starch were also conducted. The results showed that the addition of PEM increased pasting temperature and decreased other pasting parameters. Increasing PEM concentrations resulted in increased gelatinisation temperature and enthalpy.

  19. Conversion of corn milling low-value co-products to ethanol

    Energy Technology Data Exchange (ETDEWEB)

    Dien, B.S.; Hespell, R.B.; Bothast, R.J. [Dept. of Agriculture, Peoria, IL (United States); Ingram, L.O. [Univ. of Florida, Gainesville, FL (United States)

    1996-12-31

    Most of the fuel ethanol produced in the United States is derived from corn starch. The ethanol yield can be significantly increased if the hemicellulose fraction of the corn kernel is also fermented. The hemicellulose and cellulose fractions are presently marketed as cattle feed. Conversion of the hemicellulose fraction to ethanol is problematic because, in addition to glucose from the residual starch, hydrolysis of the hemicellulose gives a mixture of pentoses (arabinose and xylose) and traditional industrial yeast do not ferment pentoses. We have evaluated non-traditional recombinant microorganisms for conversion of the hemicellulose fractions into ethanol. The hemicellulose were hydrolyzed with weak acid solutions and resulting sugar mixtures fermented using recombinant Escherichia coli strains K011 and SL40. Results of the fermentation are discussed in terms of volumetric ethanol production rates, ethanol yields, and effect of inhibitors produced during hydrolysis. 4 refs., 7 figs.

  20. Synthesis of a tetra- and a trisaccharide related to an anti-tumor saponin "Julibroside J28" from Albizia julibrissin.

    Science.gov (United States)

    Roy, Bimalendu; Pramanik, Kausikisankar; Mukhopadhyay, Balaram

    2008-02-01

    Simple and convergent synthesis of a tetra- and a trisaccharide portions of an antitumor compound Julibroside J(28), isolated from Albizia julibrissin, that showed significant in vitro antitumor activity against HeLa, Bel-7402 and PC-3M-1E8 cancer cell lines is reported. The tetrasaccharide has been synthesized as its p-methoxyphenyl glycoside starting from commercially available D-glucose, L-rhamnose and L-arabinose. The trisaccharide part has been synthesized from commercially available N-acetyl D-glucosamine, D-fucose and D-xylose using simple protecting group manipulations. Sulfuric acid immobilized on silica has been used successfully as a Brönsted acid catalyst for the crucial glycosylation steps.

  1. Accumulation of recalcitrant xylan in mushroom-compost is due to a lack of xylan substituent removing enzyme activities of Agaricus bisporus.

    Science.gov (United States)

    Jurak, Edita; Patyshakuliyeva, Aleksandrina; Kapsokalyvas, Dimitris; Xing, Lia; van Zandvoort, Marc A M J; de Vries, Ronald P; Gruppen, Harry; Kabel, Mirjam A

    2015-11-05

    The ability of Agaricus bisporus to degrade xylan in wheat straw based compost during mushroom formation is unclear. In this paper, xylan was extracted from the compost with water, 1M and 4M alkali. Over the phases analyzed, the remaining xylan was increasingly substituted with (4-O-methyl-)glucuronic acid and arabinosyl residues, both one and two arabinosyl residues per xylosyl residue remained. In the 1M and 4M KOH soluble solids of spent compost, 33 and 49 out of 100 xylosyl residues, respectively, were substituted. The accumulation of glucuronic acid substituents matched with the analysis that the two A. bisporus genes encoding for α-glucuronidase activity (both GH115) were not expressed in the A. bisporus mycelium in the compost during fruiting. Also, in a maximum likelihood tree it was shown that it is not likely that A. bisporus possesses genes encoding for the activity to remove arabinose from xylosyl residues having two arabinosyl residues.

  2. Chemical Characteristics and Antioxidant Properties of Crude Water Soluble Polysaccharides from Four Common Edible Mushrooms

    Directory of Open Access Journals (Sweden)

    Pei-Long Sun

    2012-04-01

    Full Text Available Four crude water soluble polysaccharides, CABP, CAAP, CFVP and CLDP, were isolated from common edible mushrooms, including Agaricus bisporus, Auricularia auricula, Flammulina velutipes and Lentinus edodes, and their chemical characteristics and antioxidant properties were determined. Fourier Transform-infrared analysis showed that the four crude polysaccharides were all composed of β-glycoside linkages. The major monosaccharide compositions were D-galactose, D-glucose and D-mannose for CABP, CAAP and CLDP, while CFVP was found to consist of L-arabinose, D-galactose, D-glucose and D-mannose. The main molecular weight distributions of CABP and the other three polysaccharides were 66.0 × 104 Da, respectively. Antioxidant properties of the four polysaccharides were evaluated in in vitro systems and CABP showed the best antioxidant properties. The studied mushroom species could potentially be used in part of well-balanced diets and as a source of antioxidant compounds.

  3. Combined steam pretreatment and enzymatic hydrolysis of starch-free wheat fibers.

    Science.gov (United States)

    Palmarola-Adrados, Beatriz; Galbe, Mats; Zacchi, Guido

    2004-01-01

    Steam treatment of an industrial process stream, denoted starch-free wheat fiber, was investigated to improve the formation of monomeric sugars in subsequent enzymatic hydrolysis for further bioconversion into ethanol. The solid fraction in the process stream, derived from a combined starch and ethanol factory, was rich in arabinose (21.1%), xylose (30.1%), and glucose (18.6%), in the form of polysaccharides. Various conditions of steam pretreatment (170-220 degrees C for 5-30 min) were evaluated, and their effect was assessed by enzymatic hydrolysis with 2 g of Celluclast + Ultraflo mixture/100 g of starch-free fiber (SFF) slurry at 5% dry matter (DM). The highest overall sugar yield for the combined steam pretreatment and enzymatic hydrolysis, 52 g/100 g of DM of SFF, corresponding to 74% of the theoretical, was achieved with pretreatment at 190 degrees C for 10 min followed by enzymatic hydrolysis.

  4. Improvement of hemicellulose hydrolysis of corncobs

    Energy Technology Data Exchange (ETDEWEB)

    Nikolaeva, N.S.; Filatova, A.M.; Barysheva, O.N.; Abroskina, L.A.; Andrianova, A.K.

    1981-01-01

    Impregnation of corncobs with H/sub 2/SO/sub 4/ solution at 80-90 degrees, hydrolysis with 1.5% H/sub 2/SO/sub 4/ at 120-125 degrees, and 2-stage extraction of hydrolysis products from lignocellulose with sugar solution, obtained in the 1st stage of extraction, at 60-80 degrees gave hydrolysates containing 8.2% reducing substances with pentose yield of 36.0%. By this method, the content of actual sugar, monosaccharides (after clarification with ion exchangers) and xylose in hydrolysates was increased from 80.2% to 88.0%, 93% to 96% and 76.3% to 78.8%, respectively, whereas the content of arabinose, glucose, and galactose was decreased from 23.7% to 21.2%.

  5. Molar extinction coefficients of some carbohydrates in aqueous solutions

    Indian Academy of Sciences (India)

    K Singh; G K Sandhu; B S Lark; S P Sud

    2002-03-01

    Molar extinction coefficients of some carbohydrates viz. L-arabinose (C5H10O5), D-glucose (C6H12O6), D-mannose (C6H12O6), D-galactose (C6H12O6), D(-) fructose (C6H12O6) and maltose (C12H24O12) in aqueous solutions have been determined at 81, 356, 511, 662, 1173 and 1332 keV by gamma ray transmission method in a narrow beam good geometry set-up. These coefficients have been found to depend upon the photon energy following a 4-parameter polynomial. These extinction coefficients for different sugars having the same molecular formula have same values varying within experimental uncertainty. Within concentration ranges studied, Beer–Lambert law is obeyed very well.

  6. Final classification of Bisgaard taxon 9 as Actinobacillus arthritidis sp nov and recognition of a novel genomospecies for equine strains of Actinobacillus lignieresii

    DEFF Research Database (Denmark)

    Christensen, Henrik; Bisgaard, Magne; Angen, Øystein;

    2002-01-01

    Phenotypic characterization of bacteria from diseased and healthy horses identified 18 isolates as Bisgaard taxon 9 and 11 isolates as Actinobacillus lignieresii. All strains of taxon 9 were alpha-galactosidase- and raffinose-positive and showed variable fermentation of (+)L-arabinose and (-)D-sorbitol....... Strains of A. lignieresii were negative for these characteristics, with the exception of raffinose. Two strains from the (-)D-sorbitol-negative group of taxon 9 showed a 16S rRNA similarity of 99.6%, while 99.5% similarity was found between two strains of the (-)D-sorbitol-positive group. DNA......-DNA hybridization between the two strains representing the (-)D-sorbitol-negative group showed 98% binding, and their closest relationship was to a strain of A. lignieresii (64%). The two strains of the (-)D-sorbitol-positive group showed 83% binding and were related to the (-)D-sorbitol-negative group at a 76% DNA...

  7. Isolation of pectin-enriched products from red beet (Beta vulgaris L. var. conditiva) wastes: composition and functional properties.

    Science.gov (United States)

    Fissore, E N; Ponce, N M A; Matkovic, L; Stortz, C A; Rojas, A M; Gerschenson, L N

    2011-12-01

    The present work was dedicated to the development of an extraction process for red beet (Beta vulgaris L. var. conditiva) by-products that preserves the high molecular weight of the macromolecules with the primary aim of waste upgrading. Our study concerns the extraction of pectin-enriched products with potential thickening properties for their usage in food formulation, as well as with some healthy physiological effect, by using citrate buffer (pH = 5.2) either alone or with enzymes (hemicellulase or cellulase) active on cell wall polysaccharide networks. Considering that red beet tissue contains ferulic acid, which cross-links pectin macromolecules through arabinose residues to anchor them into the cell wall, an alkaline pretreatment was also evaluated in order to perform polysaccharide hydrolysis in the cell wall network to accomplish higher renderings. Chemical composition and yield, as well as the in vitro glucose retention exerted by the isolated fiber products were finally analyzed.

  8. PmrB Mutations Promote Polymyxin Resistance of Pseudomonas aeruginosa Isolated from Colistin-Treated Cystic Fibrosis Patients

    DEFF Research Database (Denmark)

    Moskowitz, Samuel M; Brannon, Mark K; Dasgupta, Nandini

    2012-01-01

    Pseudomonas aeruginosa can develop resistance to polymyxin and other cationic antimicrobial peptides. Previous work has shown that mutations in the PmrAB and PhoPQ regulatory systems can confer low to moderate levels of colistin (polymyxin E) resistance in laboratory strains and clinical isolates...... induced transcription from the promoter of the arnB operon and stimulated addition of 4-amino-l-arabinose to lipid A, consistent with the known role of this lipid A modification in polymyxin resistance. For some highly polymyxin-resistant clinical isolates, repeated passage without antibiotic selection...... of this organism (MICs of 8 to 64 mg/liter). To explore the role of PmrAB in high-level clinical polymyxin resistance, P. aeruginosa isolates from chronically colistin-treated cystic fibrosis patients, most with colistin MICs of >512 mg/liter, were analyzed. These cystic fibrosis isolates contained probable gain...

  9. Structural differences among alkali-soluble arabinoxylans from maize (Zea mays), rice (Oryza sativa), and wheat (Triticum aestivum) brans influence human fecal fermentation profiles.

    Science.gov (United States)

    Rose, Devin J; Patterson, John A; Hamaker, Bruce R

    2010-01-13

    Human fecal fermentation profiles of maize, rice, and wheat bran and their dietary fiber fractions released by alkaline-hydrogen peroxide treatment (principally arabinoxylan) were obtained with the aim of identifying and characterizing fractions associated with high production of short chain fatty acids and a linear fermentation profile for possible application as a slowly fermentable dietary fiber. The alkali-soluble fraction from maize bran resulted in the highest short chain fatty acid production among all samples tested, and was linear over the 24 h fermentation period. Size-exclusion chromatography and (1)H NMR suggested that higher molecular weight and uniquely substituted arabinose side chains may contribute to these properties. Monosaccharide disappearance data suggest that maize and rice bran arabinoxylans are fermented by a debranching mechanism, while wheat bran arabinoxylans likely contain large unsubstituted xylose regions that are fermented preferentially, followed by poor fermentation of the remaining, highly branched oligosaccharides.

  10. In vitro assessment of the prebiotic potential of Aloe vera mucilage and its impact on the human microbiota.

    Science.gov (United States)

    Gullón, Beatriz; Gullón, Patricia; Tavaria, Freni; Alonso, José Luis; Pintado, Manuela

    2015-02-01

    Aloe vera mucilage is reported to be rich in acemannan that is a polysaccharide with a backbone of β-(1→4)-D-mannose residues acetylated at the C-2 and C-3 positions and contains some side chains of galactose and arabinose attached to the C-6 carbon. The evaluation of the prebiotic potential of Aloe vera mucilage was carried out by in vitro fermentation using intestinal microbiota from six healthy donors as the inoculum. The prebiotic activity was assessed through the quantification of short chain fatty acids (SCFA) and the evaluation of dynamic bacterial population in mixed faecal cultures by fluorescence in situ hybridization (FISH). Our findings support the possible incorporation of the Aloe vera mucilage in the development of a variety of food products known as prebiotics aimed at improving gastrointestinal health.

  11. Tyrosine Phosphorylation of the UDP-Glucose Dehydrogenase of Escherichia coli Is at the Crossroads of Colanic Acid Synthesis and Polymyxin Resistance

    DEFF Research Database (Denmark)

    Lacour, S.; Bechet, E.; Cozzone, A.J.

    2008-01-01

    -kinases have been characterized. BY-kinases have been shown to participate in various physiological processes. Nevertheless, we are at a very early stage of defining their importance in the bacterial cell. In Escherichia coli, two BY-kinases, Wzc and Etk, have been characterized biochemically. Wzc has been...... shown to phosphorylate the UDP-glucose dehydrogenase Ugd in vitro. Not only is Ugd involved in the biosynthesis of extracellular polysaccharides, but also in the production of UDP-4-amino-4-deoxy-L-arabinose, a compound that renders E. coli resistant to cationic antimicrobial peptides. Methodology....../Principal Findings: Here, we studied the role of Ugd phosphorylation. We first confirmed in vivo the phosphorylation of Ugd by Wzc and we demonstrated that Ugd is also phosphorylated by Etk, the other BY-kinase identified in E. coli. Tyrosine 71 (Tyr71) was characterized as the Ugd site phosphorylated by both Wzc...

  12. Structural Characterization of a Polysaccharide From the Roots of Angelica Sinensis (Oliv) Diels by Gas Chromatography-Mass Spectrometry%气相色谱-质谱法研究当归多糖的糖链联接方式

    Institute of Scientific and Technical Information of China (English)

    徐桂云; 陈汝贤

    2004-01-01

    X-C-3- Ⅱ, a polysaccharide having immunologic adjuvanticity was extracted and purified from the roots of Angelica sinensis (Oliv) Diels. Its linkage was elucidated by selective hydrolysis and GC-MS analysis of its derivatives, as well as its 1H and 13C NMR spectra. This polysaccharide was composed of arabinose, galactose, glucose and fructose with a molar ratio of 1 : 1 : 4 : 9, and it had a highly branched structure with a fructofuranosyl backbone. The sequence of the repeating unit of X-C-3- Ⅱ was deduced. To our best knowledge, this is the first report of the fructose residue in polysaccharides from the rootsof Angelica sinensis (Oliv) Diels.

  13. Structural characterization and DPPH· radical scavenging activity of a polysaccharide from Guara fruits.

    Science.gov (United States)

    Hua, Dehong; Zhang, Dezhi; Huang, Bing; Yi, Pan; Yan, Chunyan

    2014-03-15

    The crude polysaccharides were extracted from fruits of Psidium guajava Linn. by hot water. After removal of proteins, isolation and purification by DEAE-52 Cellulose chromatography and Sephadex G-75 gel filtration, a polysaccharide (GP70-2) was obtained and structurally characterized. GP70-2 has a relative molecular weight of 74 kDa and was composed of D-galactose and L-arabinose in the ratio of 1:1, with a specific optical rotation of [a]D(25) = +101°. Structural characterization of this novel polysaccharide was carried out using infrared spectroscopy, methylation analyses, and NMR studies ((1)H, (13)C, (1)H-(1)H-COSY, HMQC, and HMBC). Based on the above data, the following structure was assigned to the repeated core unit of GP70-2: [Formula: see text]. This polysaccharide showed a concentration dependent DPPH· radical scavenging activity.

  14. Structure of the Escherichia coli ArnA N-formyltransferase domain in complex with N(5) -formyltetrahydrofolate and UDP-Ara4N.

    Science.gov (United States)

    Genthe, Nicholas A; Thoden, James B; Holden, Hazel M

    2016-08-01

    ArnA from Escherichia coli is a key enzyme involved in the formation of 4-amino-4-deoxy-l-arabinose. The addition of this sugar to the lipid A moiety of the lipopolysaccharide of pathogenic Gram-negative bacteria allows these organisms to evade the cationic antimicrobial peptides of the host immune system. Indeed, it is thought that such modifications may be responsible for the repeated infections of cystic fibrosis patients with Pseudomonas aeruginosa. ArnA is a bifunctional enzyme with the N- and C-terminal domains catalyzing formylation and oxidative decarboxylation reactions, respectively. The catalytically competent cofactor for the formylation reaction is N(10) -formyltetrahydrofolate. Here we describe the structure of the isolated N-terminal domain of ArnA in complex with its UDP-sugar substrate and N(5) -formyltetrahydrofolate. The model presented herein may prove valuable in the development of new antimicrobial therapeutics.

  15. Antioxidant activity of herbal polysaccharides and cough reflex.

    Science.gov (United States)

    Nosalova, G; Jurecek, L; Hromadkova, Z; Kostalova, Z; Sadlonova, V

    2013-01-01

    The extraction of Fallopia sachalinensis leaves resulted in two fractions (FS-1 and FS-2). Chemical and spectral analyses of samples revealed the prevalence of pectic polysaccharides with high galacturonic acid, arabinose, galactose, and rhamnose content. Arabinogalactan with a higher content of phenolic prevailed in the FS-1, whereas rhamnogalacturonan predominated in the FS-2 fraction. Both polysaccharides showed significant antioxidant activity according to DPPH and FRAP assays. Evaluation of antitussive activity in healthy adult conscious guinea pigs after oral application of 50 and 75 mg/kg of the FS-2 polysaccharide extracts showed a significant suppression of cough reflex, without an influence on specific airway resistance. The suppression of cough was comparable with that of codeine.

  16. Non-cellulosic polysaccharides from cotton fibre are differently impacted by textile processing

    DEFF Research Database (Denmark)

    Runavot, Jean-Luc; Guo, Xiaoyuan; Willats, William George Tycho;

    2014-01-01

    Cotton fibre is mainly composed of cellulose, although non-cellulosic polysaccharides play key roles during fibre development and are still present in the harvested fibre. This study aimed at determining the fate of non-cellulosic polysaccharides during cotton textile processing. We analyzed non......-cellulosic cotton fibre polysaccharides during different steps of cotton textile processing using GC-MS, HPLC and comprehensive microarray polymer profiling to obtain monosaccharide and polysaccharide amounts and linkage compositions. Additionally, in situ detection was used to obtain information on polysaccharide...... localization and accessibility. We show that pectic and hemicellulosic polysaccharide levels decrease during cotton textile processing and that some processing steps have more impact than others. Pectins and arabinose-containing polysaccharides are strongly impacted by the chemical treatments, with most being...

  17. 气相色谱-质谱法研究当归多糖的糖链联接方式

    Institute of Scientific and Technical Information of China (English)

    徐桂云; 陈汝贤

    2004-01-01

    X-C-3- Ⅱ, a polysaccharide having immunologic adjuvanticity was extracted and purified from the roots of Angelica sinensis (Oliv) Diels. Its linkage was elucidated by selective hydrolysis and GC-MS analysis of its derivatives, as well as its 1H and 13C NMR spectra. This polysaccharide was composed of arabinose, galactose, glucose and fructose with a molar ratio of 1 : 1 : 4 : 9, and it had a highly branched structure with a fructofuranosyl backbone. The sequence of the repeating unit of X-C-3- Ⅱ was deduced. To our best knowledge, this is the first report of the fructose residue in polysaccharides from the rootsof Angelica sinensis (Oliv) Diels.

  18. Polysaccharides from the green seaweeds Codium fragile and C. vermilara with controversial effects on hemostasis.

    Science.gov (United States)

    Ciancia, Marina; Quintana, Irene; Vizcargüénaga, María Isabel; Kasulin, Luciana; de Dios, Agustina; Estevez, José Manuel; Cerezo, Alberto Saúl

    2007-12-01

    Codium fragile and Codium vermilara biosynthesize water-soluble sulfated arabinans and galactans (and/or sulfated arabinogalactans), alpha(1-->4)-D-glucans and beta(1-->4)-D-mannans. The former polysaccharides are composed by 3-linked beta-D-galactopyranose and beta-L-arabinopyranose residues, they are highly sulfated and substituted with pyruvic acid ketals. For both seaweeds, they have the same main structural units, but in different percentages. All the room-temperature water extracts from both seaweeds showed a dual haemostatic effect: they prevented coagulation, but they induced platelet aggregation. Anticoagulant activity and platelet aggregation were higher in the samples with polysaccharides richer in sulfate, mainly in those from C. vermilara, which have a higher degree of sulfation and arabinose content.

  19. A review about the development of fucoidan in antitumor activity: Progress and challenges.

    Science.gov (United States)

    Wu, Lei; Sun, Jing; Su, Xitong; Yu, Qiuli; Yu, Qiuyang; Zhang, Peng

    2016-12-10

    Fucoidan is composed of l-fucose, sulfate groups and one or more small proportions of d-xylose, d-mannose, d-galactose, l-rhamnose, arabinose, glucose, d-glucuronic acid and acetyl groups in different kinds of brown seaweeds. Many reports have demonstrated that fucoidan has antitumor activities on various cancers. However, until now, few reviews have discussed the antitumor activity of fucoidan and few reports have summarized detailed molecular mechanisms of its actions and antitumor challenges of fucoidan specially. In this review, the antitumor signaling pathway mechanisms related to fucoidan are elucidated as much detail as possible. Besides, the factors affecting the anticancer effects of fucoidan, the structural characteristics of fucoidan with anticancer activities and the challenges for the further development of fucoidan are also summarized and evaluated. The existing similar and different conclusions are summarized in an attempt to provide guidelines to help further research, and finally contribute to go into market as chemotherapeumtics.

  20. Binding of different monosaccharides by lectin PA-IIL from Pseudomonas aeruginosa: thermodynamics data correlated with X-ray structures.

    Science.gov (United States)

    Sabin, Charles; Mitchell, Edward P; Pokorná, Martina; Gautier, Catherine; Utille, Jean-Pierre; Wimmerová, Michaela; Imberty, Anne

    2006-02-06

    The lectin from Pseudomonas aeruginosa (PA-IIL) is involved in host recognition and biofilm formation. Lectin not only displays an unusually high affinity for fucose but also binds to L-fucose, L-galactose and D-arabinose that differ only by the group at position 5 of the sugar ring. Isothermal calorimetry experiments provided precise determination of affinity for the three methyl-glycosides and revealed a large enthalpy contribution. The crystal structures of the complexes of PA-IIL with L-galactose and Met-beta-D-arabinoside have been determined and compared with the PA-IIL/fucose complex described previously. A combination of the structures and thermodynamics provided clues for the role of the hydrophobic group in affinity.

  1. Controlled enzyme catalyzed heteropolysaccharide degradation

    DEFF Research Database (Denmark)

    Rasmussen, Louise Enggaard

    The work presented in this PhD thesis has provided a better understanding of the enzyme kinetics and quantitative phenomena of the hydrolysis of xylan substrates by selected pure enzyme preparations. Furthermore, the options for producing specific substituted xylooligosaccharides from selected...... substrates by specific xylanase treatment have been examined. The kinetics of the enzymatic degradation of water-extractable wheat arabinoxylan (WE-AX) during designed treatments with selected monocomponent enzymes was investigated by monitoring the release of xylose and arabinose. The results of different...... between -xylosidase and the α-L-arabinofuranosidases on the xylose release were low as compared to the effect of xylanase addition with β-xylosidase, which increased the xylose release by ~25 times in 30 minutes. At equimolar addition levels of the four enzymes, the xylanase activity was thus rate...

  2. Furfural Production from d-Xylose and Xylan by Using Stable Nafion NR50 and NaCl in a Microwave-Assisted Biphasic Reaction

    Directory of Open Access Journals (Sweden)

    Sarah Le Guenic

    2016-08-01

    Full Text Available Pentose dehydration and direct transformation of xylan into furfural were performed in a water-cyclopentyl methyl ether (CPME biphasic system under microwave irradiation. Heated up between 170 and 190 °C in the presence of Nafion NR50 and NaCl, d-xylose, l-arabinose and xylan gave furfural with maximum yields of 80%, 42% and 55%, respectively. The influence of temperature and reaction time on the reaction kinetics was discussed. This study was also completed by the survey of different reactant ratios, such as organic layer-water or catalyst-inorganic salt ratios. The exchange between proton and cation induced by an excess of NaCl was monitored, and a synergetic effect between the remaining protons and the released HCl was also discovered.

  3. Effect of a Thermoascus aurantiacus thermostable enzyme cocktail on wheat bread qualitiy.

    Science.gov (United States)

    Oliveira, D S; Telis-Romero, J; Da-Silva, R; Franco, C M L

    2014-01-15

    Thermophilic fungus Thermoascus aurantiacus (CBMAI 756) on solid-state fermentation using corncob as a nutrient source produces an enzyme pool with the potential to be used in bread making. In this paper, the use of this enzyme cocktail as a wheat bread improver was reported. Both products released by flour arabinoxylan degradation and bread quality were investigated. The main product released through enzyme activity after prolonged incubation was xylose indicating the presence of xylanase; however, a small amount of xylobiose and arabinose also confirmed the presence of xylosidase and α-l-arabinofuranosidase, respectively. Enzyme mixture "in vitro" mainly attacked water-unextractable arabinoxylan contributing to beneficial effect in bread making. The use of an optimal enzyme concentration (35U xylanase/100g of flour) increased specific volume (22%), reduced crumb firmness (25%), and reduced amylopectin retrogradation (17%) during bread storage. In conclusion, the enzyme cocktail produced by T. aurantiacus CBMAI 756 can improve wheat bread quality.

  4. Use of Per-C-Deuterated myo-Inositol for Study of Cell Wall Synthesis in Germinating Beans.

    Science.gov (United States)

    Sasaki, K; Nagahashi, G; Gretz, M R; Taylor, I E

    1989-06-01

    Cell wall polysaccharides of the hypocotyl and roots in germinating beans (Phaseolus vulgaris L.) were selectively labeled in arabinosyl, xylosyl, and galacturonosyl residues by per-C-deuterated myo-inositol, which was introduced through 72 hours of imbibition. Glucuronate residues remained unlabeled. Selected ion gas chromatography-mass spectrometry analysis revealed that deuterium was not redistributed in these three sugar residues or into other carbohydrate residues during this conversion, suggesting that the labeled residues are formed exclusively via the myo-inositol oxidation pathway and that no glucogenesis from myo-inositol takes place during this conversion. The presence of a significant level of deuterated arabinose, xylose, and galacturonate after just 72 hours of imbibitional uptake of per-C-deuterated myo-inositol indicated that the myo-inositol oxidation pathway has a predominant role in the biosynthesis of new cell walls.

  5. Draft genome sequence of Microbacterium oleivorans strain Wellendorf implicates heterotrophic versatility and bioremediation potential

    Directory of Open Access Journals (Sweden)

    Anton P. Avramov

    2016-12-01

    Full Text Available Microbacterium oleivorans is a predominant member of hydrocarbon-contaminated environments. We here report on the genomic analysis of M. oleivorans strain Wellendorf that was isolated from an indoor door handle. The partial genome of M. oleivorans strain Wellendorf consists of 2,916,870 bp of DNA with 2831 protein-coding genes and 49 RNA genes. The organism appears to be a versatile mesophilic heterotroph potentially capable of hydrolysis a suite of carbohydrates and amino acids. Genomic analysis revealed metabolic versatility with genes involved in the metabolism and transport of glucose, fructose, rhamnose, galactose, xylose, arabinose, alanine, aspartate, asparagine, glutamate, serine, glycine, threonine and cysteine. This is the first detailed analysis of a Microbacterium oleivorans genome.

  6. Lectin Activity in Gut Extract of Culex Pipiens

    Directory of Open Access Journals (Sweden)

    Mona Koosha

    2013-03-01

    Full Text Available Background: The role of lectins is important in interaction between pathogens and mosquito vectors. This study was performed to identify agglutinin activities of protein molecules on the midgut of Culex pipiens. Methods: Culex pipiens was reared in insectray condition and the midguts of males and females (blood fed and un­fed were dissected separately in Tris-HCl buffer. The extracts of midguts were applied for hemagglutinin assay against red blood cells of rabbit, mouse, rat, dog, horse, sheep, guinea pig, cow, human (A, B, AB, O groups. Then, the RBCs with relatively high agglutinin activity were chosen for carbohydrate inhibition assay. D (+ glucose, D (+ galactose, D (+ mannose, D (- fructose, D (- arabinose, L (- fucose, lactose, N-acetyl-D-glucosamine, N-acetyl-D-galactosamine, sialic acid were used to specify carbohydrate binding lectin.Results: The highest agglutinin activities were found against sheep and rabbits RBCs. Sexual diversity of agglutinin activities was observed among midgut extraction of males and females. In addition, variation in agglutinin activity of blood fed and unfed female mosquitoes were detected. The lectin activity was inhibited highly with glucose, galactose, fucose and fructose but less inhibitor activities was observed by arabinose, N-acetyl-D-galactosamine, n-acetyl-d-glucosamine, lactose and mannose.Conclusion: The secretion of hemagglutinins (lectins or lectin-like molecules in the digestive system depends on the type of food in the gut. This suggests that emptying of the gut in preparation for protein rich food probably starts the secretion of hemagglutinins.

  7. Evolution of Xylan Substitution Patterns in Gymnosperms and Angiosperms: Implications for Xylan Interaction with Cellulose.

    Science.gov (United States)

    Busse-Wicher, Marta; Li, An; Silveira, Rodrigo L; Pereira, Caroline S; Tryfona, Theodora; Gomes, Thiago C F; Skaf, Munir S; Dupree, Paul

    2016-08-01

    The interaction between cellulose and xylan is important for the load-bearing secondary cell wall of flowering plants. Based on the precise, evenly spaced pattern of acetyl and glucuronosyl (MeGlcA) xylan substitutions in eudicots, we recently proposed that an unsubstituted face of xylan in a 2-fold helical screw can hydrogen bond to the hydrophilic surfaces of cellulose microfibrils. In gymnosperm cell walls, any role for xylan is unclear, and glucomannan is thought to be the important cellulose-binding polysaccharide. Here, we analyzed xylan from the secondary cell walls of the four gymnosperm lineages (Conifer, Gingko, Cycad, and Gnetophyta). Conifer, Gingko, and Cycad xylan lacks acetylation but is modified by arabinose and MeGlcA. Interestingly, the arabinosyl substitutions are located two xylosyl residues from MeGlcA, which is itself placed precisely on every sixth xylosyl residue. Notably, the Gnetophyta xylan is more akin to early-branching angiosperms and eudicot xylan, lacking arabinose but possessing acetylation on alternate xylosyl residues. All these precise substitution patterns are compatible with gymnosperm xylan binding to hydrophilic surfaces of cellulose. Molecular dynamics simulations support the stable binding of 2-fold screw conifer xylan to the hydrophilic face of cellulose microfibrils. Moreover, the binding of multiple xylan chains to adjacent planes of the cellulose fibril stabilizes the interaction further. Our results show that the type of xylan substitution varies, but an even pattern of xylan substitution is maintained among vascular plants. This suggests that 2-fold screw xylan binds hydrophilic faces of cellulose in eudicots, early-branching angiosperm, and gymnosperm cell walls.

  8. Fermentation of lignocellulosic sugars to acetic acid by Moorella thermoacetica.

    Science.gov (United States)

    Ehsanipour, Mandana; Suko, Azra Vajzovic; Bura, Renata

    2016-06-01

    A systematic study of bioconversion of lignocellulosic sugars to acetic acid by Moorella thermoacetica (strain ATCC 39073) was conducted. Four different water-soluble fractions (hydrolysates) obtained after steam pretreatment of lignocellulosic biomass were selected and fermented to acetic acid in batch fermentations. M. thermoacetica can effectively ferment xylose and glucose in hydrolysates from wheat straw, forest residues, switchgrass, and sugarcane straw to acetic acid. Xylose and glucose were completely utilized, with xylose being consumed first. M. thermoacetica consumed up to 62 % of arabinose, 49 % galactose and 66 % of mannose within 72 h of fermentation in the mixture of lignocellulosic sugars. The highest acetic acid yield was obtained from sugarcane straw hydrolysate, with 71 % of theoretical yield based on total sugars (17 g/L acetic acid from 24 g/L total sugars). The lowest acetic acid yield was observed in forest residues hydrolysate, with 39 % of theoretical yield based on total sugars (18 g/L acetic acid from 49 g/L total sugars). Process derived compounds from steam explosion pretreatment, including 5-hydroxymethylfurfural (0.4 g/L), furfural (0.1 g/L) and total phenolics (3 g/L), did not inhibit microbial growth and acetic acid production yield. This research identified two major factors that adversely affected acetic acid yield in all hydrolysates, especially in forest residues: (i) glucose to xylose ratio and (ii) incomplete consumption of arabinose, galactose and mannose. For efficient bioconversion of lignocellulosic sugars to acetic acid, it is imperative to have an appropriate balance of sugars in a hydrolysate. Hence, the choice of lignocellulosic biomass and steam pretreatment design are fundamental steps for the industrial application of this process.

  9. Comparing MALDI-TOF Mass Spectrometry with Molecular and Biochemical Methods in Identifying Enterococcus Faecium and Enterococcus Faecalis Isolated from Clinical

    Directory of Open Access Journals (Sweden)

    Samadi Kafil,H.

    2013-01-01

    Full Text Available Abstract Background and Objective: Enterococci are Gram-positive members of human gastrointestinal flora, in Dairy products and environment. they have emerged as important causes of opportunistic nosocomial infections in recent years. In this study we aimed to investigat and compare the efficiency of MALDI-TOF mass spectroscopy method through Biochemical and Molecular methods for detecting Enterococcus faecalis and Enterococcus faecium.Materials and Methods: seventhy five clinical samples were collected for biochemical, molecular and mass spectroscopy investigations. Samples were treated with Esculin hydrolysis, Catalase, Pyrrolidonyl aminopeptidase, 6.5% NaCl solution, motility, 0.04% Tellurite, L-Arabinose and Sorbitol. Using specific primes allele specific PCR was used.The samples were then analyzed by MALDI-TOF mass spectroscopy and Biotyper 3 software.Results: Enterococcus faecium and Enterococcus faecalis were detected in thirty and forty two samples, respectively whereas three samples showed both bacterial infections. Using biochemical analysis, two E. faecium isolates were Arabinose negative and one E. faecalis isolates was Telliurite negative. All samples were showed correct bands in PCR results but two of them didn't show clear bands(on agarose gel. In mass spectroscopy analysis all strains were correctly detected and well defined.Conclusion: According to our results, MALDI-TOF mass spectrometry in comparison with Molecular and Biochemical Methods could be a reliable and accurate method that can easily and quickly identify and differentiate Enterococcus faecium and Enterococcus faecalis in clinical samples.Key words: Enterococcus faecalis, Enterococcus faecium, MALDI-TOF mass spectrometry, PCR

  10. Mechanistic strategies for catalysis adopted by evolutionary distinct family 43 arabinanases.

    Science.gov (United States)

    Santos, Camila R; Polo, Carla C; Costa, Maria C M F; Nascimento, Andrey F Z; Meza, Andreia N; Cota, Junio; Hoffmam, Zaira B; Honorato, Rodrigo V; Oliveira, Paulo S L; Goldman, Gustavo H; Gilbert, Harry J; Prade, Rolf A; Ruller, Roberto; Squina, Fabio M; Wong, Dominic W S; Murakami, Mário T

    2014-03-14

    Arabinanases (ABNs, EC 3.2.1.99) are promising catalysts for environmentally friendly biomass conversion into energy and chemicals. These enzymes catalyze the hydrolysis of the α-1,5-linked L-arabinofuranoside backbone of plant cell wall arabinans releasing arabino-oligosaccharides and arabinose, the second most abundant pentose in nature. In this work, new findings about the molecular mechanisms governing activation, functional differentiation, and catalysis of GH43 ABNs are presented. Biophysical, mutational, and biochemical studies with the hyperthermostable two-domain endo-acting ABN from Thermotoga petrophila (TpABN) revealed how some GH43 ABNs are activated by calcium ions via hyperpolarization of the catalytically relevant histidine and the importance of the ancillary domain for catalysis and conformational stability. On the other hand, the two GH43 ABNs from rumen metagenome, ARN2 and ARN3, presented a calcium-independent mechanism in which sodium is the most likely substituent for calcium ions. The crystal structure of the two-domain endo-acting ARN2 showed that its ability to efficiently degrade branched substrates is due to a larger catalytic interface with higher accessibility than that observed in other ABNs with preference for linear arabinan. Moreover, crystallographic characterization of the single-domain exo-acting ARN3 indicated that its cleavage pattern producing arabinose is associated with the chemical recognition of the reducing end of the substrate imposed by steric impediments at the aglycone-binding site. By structure-guided rational design, ARN3 was converted into a classical endo enzyme, confirming the role of the extended Arg(203)-Ala(230) loop in determining its action mode. These results reveal novel molecular aspects concerning the functioning of GH43 ABNs and provide new strategies for arabinan degradation.

  11. Fluorescence resonance energy transfer sensors for quantitative monitoring of pentose and disaccharide accumulation in bacteria

    Directory of Open Access Journals (Sweden)

    Looger Loren L

    2008-06-01

    Full Text Available Abstract Background Engineering microorganisms to improve metabolite flux requires detailed knowledge of the concentrations and flux rates of metabolites and metabolic intermediates in vivo. Fluorescence resonance energy transfer sensors represent a promising technology for measuring metabolite levels and corresponding rate changes in live cells. These sensors have been applied successfully in mammalian and plant cells but potentially could also be used to monitor steady-state levels of metabolites in microorganisms using fluorimetric assays. Sensors for hexose and pentose carbohydrates could help in the development of fermentative microorganisms, for example, for biofuels applications. Arabinose is one of the carbohydrates to be monitored during biofuels production from lignocellulose, while maltose is an important degradation product of starch that is relevant for starch-derived biofuels production. Results An Escherichia coli expression vector compatible with phage λ recombination technology was constructed to facilitate sensor construction and was used to generate a novel fluorescence resonance energy transfer sensor for arabinose. In parallel, a strategy for improving the sensor signal was applied to construct an improved maltose sensor. Both sensors were expressed in the cytosol of E. coli and sugar accumulation was monitored using a simple fluorimetric assay of E. coli cultures in microtiter plates. In the case of both nanosensors, the addition of the respective ligand led to concentration-dependent fluorescence resonance energy transfer responses allowing quantitative analysis of the intracellular sugar levels at given extracellular supply levels as well as accumulation rates. Conclusion The nanosensor destination vector combined with the optimization strategy for sensor responses should help to accelerate the development of metabolite sensors. The new carbohydrate fluorescence resonance energy transfer sensors can be used for in vivo

  12. Evolution of Xylan Substitution Patterns in Gymnosperms and Angiosperms: Implications for Xylan Interaction with Cellulose1[OPEN

    Science.gov (United States)

    Li, An; Gomes, Thiago C.F.

    2016-01-01

    The interaction between cellulose and xylan is important for the load-bearing secondary cell wall of flowering plants. Based on the precise, evenly spaced pattern of acetyl and glucuronosyl (MeGlcA) xylan substitutions in eudicots, we recently proposed that an unsubstituted face of xylan in a 2-fold helical screw can hydrogen bond to the hydrophilic surfaces of cellulose microfibrils. In gymnosperm cell walls, any role for xylan is unclear, and glucomannan is thought to be the important cellulose-binding polysaccharide. Here, we analyzed xylan from the secondary cell walls of the four gymnosperm lineages (Conifer, Gingko, Cycad, and Gnetophyta). Conifer, Gingko, and Cycad xylan lacks acetylation but is modified by arabinose and MeGlcA. Interestingly, the arabinosyl substitutions are located two xylosyl residues from MeGlcA, which is itself placed precisely on every sixth xylosyl residue. Notably, the Gnetophyta xylan is more akin to early-branching angiosperms and eudicot xylan, lacking arabinose but possessing acetylation on alternate xylosyl residues. All these precise substitution patterns are compatible with gymnosperm xylan binding to hydrophilic surfaces of cellulose. Molecular dynamics simulations support the stable binding of 2-fold screw conifer xylan to the hydrophilic face of cellulose microfibrils. Moreover, the binding of multiple xylan chains to adjacent planes of the cellulose fibril stabilizes the interaction further. Our results show that the type of xylan substitution varies, but an even pattern of xylan substitution is maintained among vascular plants. This suggests that 2-fold screw xylan binds hydrophilic faces of cellulose in eudicots, early-branching angiosperm, and gymnosperm cell walls. PMID:27325663

  13. A novel GH43 α-l-arabinofuranosidase of Penicillium chrysogenum that preferentially degrades single-substituted arabinosyl side chains in arabinan.

    Science.gov (United States)

    Shinozaki, Ayaka; Kawakami, Takuya; Hosokawa, Sachiko; Sakamoto, Tatsuji

    2014-05-10

    We previously described three α-l-arabinofuranosidases (ABFs) secreted by Penicillium chrysogenum 31B. Here, we purified a fourth ABF, termed PcABF43A, from the culture filtrate. The molecular mass of the enzyme was estimated to be 31kDa. PcABF43A had the highest activity at 35°C and at around pH 5. The enzyme activity was strong on sugar beet l-arabinan but weak on debranched arabinan and arabinoxylan. Low molecular-mass substrates such as p-nitrophenyl α-l-arabinofuranoside, α-1,5-l-arabinooligosaccharides, and branched arabinotriose were highly resistant to the action of PcABF43A. (1)H-NMR analysis revealed that PcABF43A hydrolyzed arabinosyl side chains linked to C-2 or C-3 of single-substituted arabinose residues in l-arabinan. Reports concerning enzymes specific for l-arabinan are quite limited. Pcabf43A cDNA encoding PcABF43A was isolated by in vitro cloning. The deduced amino acid sequence of the enzyme shows high similarities with the sequences of other fungal uncharacterized proteins. Semi-quantitative RT-PCR analysis indicated that the Pcabf43A gene was constitutively expressed in P. chrysogenum 31B at a low level, although the expression was induced with pectic components such as l-arabinose, l-rhamnose, and d-galacturonic acid. Analysis of enzymatic characteristics of PcABF43A, GH51 ABF (AFQ1), and GH54 ABF (AFS1) from P. chrysogenum suggested that PcABF43A and AFS1 function as debranching enzymes and AFQ1 plays a role of saccharification in the degradation of l-arabinan by this fungus.

  14. Kallotenue papyrolyticum gen. nov., sp. nov., a cellulolytic and filamentous thermophile that represents a novel lineage (Kallotenuales ord. nov., Kallotenuaceae fam. nov.) within the class Chloroflexia

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    Cole, Jesse; Gieler, Brandon; Heisler, Devon; Palisoc, Maryknoll; Williams, Amanda; Dohnalkova, Alice; Ming, Hong; Yu, Tian T.; Dodsworth, Jeremy A.; Li, Wen J.; Hedlund, Brian P.

    2013-08-15

    Several closely-related, thermophilic, and cellulolytic bacterial strains, designated JKG1T, JKG2, JKG3, JKG4, and JKG5, were isolated from a cellulolytic enrichment (corn stover) incubated in the water column of Great Boiling Spring, NV. Strain JKG1T had cells of a diameter of 0.7 - 0.9 μm and length of ~2.0 μm that formed non-branched multicellular filaments reaching >300 μm. Spores were not formed and dense liquid cultures were red. The temperature range for growth was 45-65 °C, with an optimum of 55 °C. The pH range for growth was 5.6-9.0, with an optimum of 7.5. JKG1T grew as an aerobic heterotroph, utilizing glucose, sucrose, xylose, arabinose, cellobiose, carboxymethylcellulose, filter paper, microcrystalline cellulose, xylan, starch, casamino acids, tryptone, peptone, yeast extract, acetate, citrate, lactate, pyruvate, and glycerol as sole carbon sources, and was not observed to photosynthesize. The cells stained Gram-negative. Phylogenetic analysis using 16S rRNA gene sequences placed the new isolates in the class Chloroflexia, but distant from other cultivated members, with the highest sequence identity of 82.5% to Roseiflexus castenholzii. The major quinone was menaquinone-9; no ubiquinones were detected. The major cellular fatty acids (>5%) were C18:0, anteiso-C17:0, iso-C18:0, and iso-C17:0. C16:0, iso-C16:0, and C17:0. The peptidoglycan amino acids were alanine, ornithine, glutamic acid, serine, and asparagine. Whole-cell sugars included mannose, rhamnose, glucose, galactose, ribose, arabinose, and xylose. Morphological, phylogenetic, and chemotaxonomic results suggest that JKG1T is representative of a new lineage within the class Chloroflexia, which we propose to designate Kallotenue papyrolyticum gen. nov., sp. nov., Kallotenuaceae fam. nov., Kallotenuales ord. nov.

  15. Characterization of the structure, expression and function of Pinus radiata D. Don arabinogalactan-proteins.

    Science.gov (United States)

    Putoczki, Tracy L; Pettolino, Filomena; Griffin, Michael D W; Möller, Ralf; Gerrard, Juliet A; Bacic, Antony; Jackson, Sandra L

    2007-10-01

    A synthetic phenylglycoside (beta-GlcY) that interacts specifically with arabinogalactan-proteins (AGPs), a class of plant cell surface proteoglycans, has been used to study the spatial distribution of AGPs in the xylem tissue of radiata pine. These studies demonstrated that AGPs were located in the compound middle lamella (CML) of the newly developed tracheid. Abundant, low salt extractable AGPs were purified from xylem tissue. Monosaccharide analysis showed that arabinose and galactose were the main sugars present. Linkage analysis showed that most of the arabinose was in the furanose form, at the terminal and 5-linked positions, and the majority of the galactose was in the pyranose form at the terminal 3-, 6- and 3,6-linked positions; a linkage composition typical of AGPs. The AGPs had an abundance of characteristic amino acid residues including alanine, hydroxyproline, proline, and serine. Separation of the AGPs using reversed-phase high performance liquid chromatography showed that one main fraction was eluted, which tested positive for AGPs by dot-blot analysis using anti-AGP monoclonal antibodies. Sedimentation equilibrium analysis showed that this main fraction contained a 226 kDa species. We have examined the function of AGPs in tracheid differentiation using an established radiata pine callus culture system grown on media containing beta-GlcY. The effect of beta-GlcY on the cultures was to reduce the overall tracheid differentiation rate in a concentration dependent manner, ultimately resulting in cell death. These studies provide further evidence that AGPs play an important role in tracheid differentiation, and thus may be an important biological target for improving wood quality.

  16. Metabolism of pentose sugars in the hyperthermophilic archaea Sulfolobus solfataricus and Sulfolobus acidocaldarius.

    Science.gov (United States)

    Nunn, Charlotte E M; Johnsen, Ulrike; Schönheit, Peter; Fuhrer, Tobias; Sauer, Uwe; Hough, David W; Danson, Michael J

    2010-10-29

    We have previously shown that the hyperthermophilic archaeon, Sulfolobus solfataricus, catabolizes d-glucose and d-galactose to pyruvate and glyceraldehyde via a non-phosphorylative version of the Entner-Doudoroff pathway. At each step, one enzyme is active with both C6 epimers, leading to a metabolically promiscuous pathway. On further investigation, the catalytic promiscuity of the first enzyme in this pathway, glucose dehydrogenase, has been shown to extend to the C5 sugars, D-xylose and L-arabinose. In the current paper we establish that this promiscuity for C6 and C5 metabolites is also exhibited by the third enzyme in the pathway, 2-keto-3-deoxygluconate aldolase, but that the second step requires a specific C5-dehydratase, the gluconate dehydratase being active only with C6 metabolites. The products of this pathway for the catabolism of D-xylose and L-arabinose are pyruvate and glycolaldehyde, pyruvate entering the citric acid cycle after oxidative decarboxylation to acetyl-coenzyme A. We have identified and characterized the enzymes, both native and recombinant, that catalyze the conversion of glycolaldehyde to glycolate and then to glyoxylate, which can enter the citric acid cycle via the action of malate synthase. Evidence is also presented that similar enzymes for this pentose sugar pathway are present in Sulfolobus acidocaldarius, and metabolic tracer studies in this archaeon demonstrate its in vivo operation in parallel with a route involving no aldol cleavage of the 2-keto-3-deoxy-pentanoates but direct conversion to the citric acid cycle C5-metabolite, 2-oxoglutarate.

  17. Enzymatic hydrolysis of potato pulp

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    Mariusz Lesiecki

    2012-03-01

    Full Text Available Background. Potato pulp constitutes a complicated system of four types of polysaccharides: cellulose, hemicellulose, pectin and starch. Its composition makes it a potential and attractive raw material for the production of the second generation bioethanol. The aim of this research project was to assess the usefulness of commercial enzymatic preparations for the hydrolysis of potato pulp and to evaluate the effectiveness of hydrolysates obtained in this way as raw materials for ethanol fermentation. Material  and methods. Sterilised potato pulp was subjected to hydrolysis with commercial enzymatic preparations. The effectiveness of the preparations declared as active towards only one fraction of potato pulp (separate amylase, pectinase and cellulase activity and mixtures of these preparations was analysed. The monomers content in hydrolysates was determined using HPLC method. Results.  The application of amylolytic enzymes for potato pulp hydrolysis resulted in the release of only 18% of raw material with glucose as the dominant (77% constituent of the formed product. In addition, 16% galactose was also determined in it. The hydrolysis of the cellulose fraction yielded up to 35% raw material and the main constituents of the obtained hydrolysate were glucose (46% and arabinose (40%. Simultaneous application of amylolytic, cellulolytic and pectinolytic enzymes turned out to be the most effective way of carrying out the process as its efficiency in this case reached 90%. The obtained hydrolysate contained 63% glucose, 25% arabinose and 12% other simple substances. Conclusion. The application of commercial enzymatic preparations made it possible to perform potato pulp hydrolysis with 90% effectiveness. This was achieved by the application of a complex of amylolytic, cellulolytic and pectinolytic enzymes and the hydrolysate obtained in this way contained, primarily, glucose making it a viable substrate for ethanol fermentation.

  18. Metabolic relationships of the isolated fractions of the pectic substances of actively growing sycamore cells.

    Science.gov (United States)

    Stoddart, R W; Northcote, D H

    1967-10-01

    1. d-Glucose and l-arabinose serve as precursors of the pectic polysaccharides of sycamore suspension-callus tissue. 2. The rates and characteristics of the incorporation of radioactive sucrose, glucose and mesoinositol by sycamore callus tissue have been compared and shown to be different. 3. The time-course of the incorporation of radioactive glucose into the major fractions within the cells has been determined. Approx. 7-10% of the radioactivity incorporated is present in the whole pectin of the cells. 4. A study of the continuous incorporation of radioactive glucose showed that the neutral arabinan-galactan fraction of the pectin quickly became saturated with the radioactive label. During the incorporation of radioactivity from a pulse of radioactive glucose the neutral fraction became progressively less labelled, with a corresponding increase in the radioactivity of the weakly acidic pectinic acid, which is known to contain neutral sugars. 5. When the cells were exposed to a pulse of radioactive l-arabinose, the label accumulated first in the neutral fraction and then after 4hr. it passed to the weakly acidic pectinic acid with a corresponding decrease in the radioactivity of the neutral fraction. 6. The product that was initially labelled during the first hour of exposure of the cells in the stationary phase to radioactive glucose was identified as an incompletely methylated galacturonan in which the radioactivity was present in the anhydrogalacturonide residues. This polysaccharide probably acts as the precursor of the polyuronide portions of both the strongly acidic and weakly acidic pectinic acids. 7. The observations are discussed in relation to the structure of the pectic substances and their function in cell growth and development. A tentative model for their metabolic relationship is put forward.

  19. Comparative Analysis of Polysaccharides from Two Ecological Types of Leymus chinensis

    Institute of Scientific and Technical Information of China (English)

    LI Jing-jing; BI Hong-tao; YAN Ji-hong; SUN Fang; FAN Sha-sha; CAO Gang; ZHOU Yi-fa; CHEN Xi-guang

    2012-01-01

    Leymus chinensis(Trin.) Tzvel.,widely distributed at eastern Eurasian steppe and divided into gray-green type and yellow-green type,has different stress resistance to environment.In the present study,the water-soluble polysaccharides from two ecotypes ofL.chinensis were analyzed in detail,and the differences between polysaccharides from the two ecotypes ofL.chinensis in the yield,monosaccharide composition,molecular weight and structure were clarified.The polysaccharides of L.chinensis were composed of both neutral and acidic polysaccharides.The neutral polysaccharides contained mannose,glucose,galactose,xylose and arabinose,and mainly consisted of β-1,4-Glcp,α-1,3-Galp and α-1,2-Xylp residues.The acidic polysaccharides contained mannose,rhamnose,glucuronic acid,galacturonic acid,glucose,galactose,xylose and arabinose.However,the yields,monosaccharides contents and the molecular weights of the polysaccharides from the two ecotypes of L.chinensis were different.Moreover,the resistance type(gray-green type) of L.chinensis contained a number of α-1,3-Manp and reducing end of β-Glcp residues,and much more O-methyl groups than normal type(yellow-green type) of L.chinensis.The differences of the polysaccharides of the two ecotypes ofL.chinensis might be due to the long-term environmental adaptability of plant,and the differences of the polysaccharides might influence the stress resistance of L.chinensis.

  20. Enzymatic hydrolysis of xylan extracted with alkali%碱法提取木聚糖的酶法水解

    Institute of Scientific and Technical Information of China (English)

    杨瑞金; 许时婴; 王璋

    2001-01-01

    在进行碱法提取木聚糖的酶法水解时,采用3%~4%的底物浓度和20U/g底物的加酶量比较合适。在优化的条件下,产品的低聚木糖含量达到79.1%(对总糖),得率达到66.8%。以去除阿拉伯糖侧链为目的,稀酸预水解对随后的碱法提取木聚糖的酶水解作用不大。这表明在木聚糖的酶水解过程中,阿拉伯糖侧链与整个木聚糖的水解同步进行。%The rational substrate concentration was 3%~4% and the properamount of xylanase was 20U/g substrate for the enzymatic hydro ly sis of xylan extracted with alkali.In the optimal condition,the product had a pu rity of 79.1% on carbohydrate basis and the yield of xylooligosacchrides could be up to 66.8%.Acidic pre-hydrolysis of the xylan extracted with alkali for rem oving the arabinose sidechain had less effect on the following enzymatic hydroly sis.It suggested that the hydrolysis of the arabinose side-chain was simultaneo us with that of the xylan.

  1. A beta-l-Arabinopyranosidase from Streptomyces avermitilis is a novel member of glycoside hydrolase family 27.

    Science.gov (United States)

    Ichinose, Hitomi; Fujimoto, Zui; Honda, Mariko; Harazono, Koichi; Nishimoto, Yukifumi; Uzura, Atsuko; Kaneko, Satoshi

    2009-09-11

    Arabinogalactan proteins (AGPs) are a family of plant cell surface proteoglycans and are considered to be involved in plant growth and development. Because AGPs are very complex molecules, glycoside hydrolases capable of degrading AGPs are powerful tools for analyses of the AGPs. We previously reported such enzymes from Streptomyces avermitilis. Recently, a beta-l-arabinopyranosidase was purified from the culture supernatant of the bacterium, and its corresponding gene was identified. The primary structure of the protein revealed that the catalytic module was highly similar to that of glycoside hydrolase family 27 (GH27) alpha-d-galactosidases. The recombinant protein was successfully expressed as a secreted 64-kDa protein using a Streptomyces expression system. The specific activity toward p-nitrophenyl-beta-l-arabinopyranoside was 18 micromol of arabinose/min/mg, which was 67 times higher than that toward p- nitrophenyl-alpha-d-galactopyranoside. The enzyme could remove 0.1 and 45% l-arabinose from gum arabic or larch arabinogalactan, respectively. X-ray crystallographic analysis reveals that the protein had a GH27 catalytic domain, an antiparallel beta-domain containing Greek key motifs, another antiparallel beta-domain forming a jellyroll structure, and a carbohydrate-binding module family 13 domain. Comparison of the structure of this protein with that of alpha-d-galactosidase showed a single amino acid substitution (aspartic acid to glutamic acid) in the catalytic pocket of beta-l-arabinopyranosidase, and a space for the hydroxymethyl group on the C-5 carbon of d-galactose bound to alpha-galactosidase was changed in beta-l-arabinopyranosidase. Mutagenesis study revealed that the residue is critical for modulating the enzyme activity. This is the first report in which beta-l-arabinopyranosidase is classified as a new member of the GH27 family.

  2. Digestibility of carbohydrates in growing pigs: a comparison between the T-cannula and the steered ileo-caecal valve cannula.

    Science.gov (United States)

    Zhang, Y C; Jörgensen, H; Fernandez, J A; Bach Knudsen, K E

    2004-06-01

    We compared the determination of ileal and total tract digestibility of carbohydrates in five experimental diets using a double 5 x 5 Latin square design involving a total of 10 cannulated pigs; half of the pigs were equipped with a simple T-cannula and the other half with steered ileo-caecal valve (SICV)-cannula. The diets consisted of nitrogen-free mixture and soya bean meal, sunflower meal, peas or rape seed cake diluted to about 180 g/kg DM protein with the nitrogen-free mixture. There was no significant difference in the digestibility values using the two types of cannulas with regard to organic matter, sugars (sum of glucose, fructose and sucrose), alpha-galactosides (sum of raffinose, stachyose and verbascose), starch, cellulose, total non-cellulosic polysaccharides (NCP) and insoluble NCP constituents. The digestibility values for the NCP residues arabinose and galactose, however, were estimated higher but with a lower variability with the SICV-cannula compared with the T-cannula. The type of cannula did no influence the estimation of the total tract digestibility for any of the major dietary constituents, but the total tract digestibility was slightly more variable when the pigs were equipped with the SICV-cannula compared with the T-cannula. There was no difference in the ileal digestibility of sugars, alpha-galactosides, cellulose and the NCP arabinose and uronic acids residues among the experimental diets, while the ileal digestibility of starch and the remaining NCP sugar residues varied between diets. The total tract digestibility was complete for sugars, alpha-galactosides and starch, whereas the digestibility of the cell wall constituents varied in accordance with the polymeric composition of the cell walls. It was concluded that ileal digesta samples from SICV-cannula are more homogenous than those from the T-cannula. In cases where the precision of each determination is crucial, the SICV-cannula should be the option.

  3. Escherichia fergusonii and Enterobacter taylorae, two new species of Enterobacteriaceae isolated from clinical specimens.

    Science.gov (United States)

    Farmer, J J; Fanning, G R; Davis, B R; O'Hara, C M; Riddle, C; Hickman-Brenner, F W; Asbury, M A; Lowery, V A; Brenner, D J

    1985-01-01

    Escherichia fergusonii (formerly known as Enteric Group 10) and Enterobacter taylorae (formerly known as Enteric Group 19) are proposed as new species in the family Enterobacteriaceae. By DNA hybridization (32P, 60 degrees C, hydroxyapatite), strains of E. fergusonii were 90 to 97% related to the type strain (holotype) ATCC 35469. They were most closely related to Escherichia coli and more distantly related to species in other genera. E. fergusonii strains are positive for indole production, methyl red, lysine decarboxylase, ornithine decarboxylase, and motility. They ferment D-glucose with gas production and also ferment adonitol, L-arabinose, L-rhamnose, maltose, D-xylose, trehalose, cellobiose, and D-arabitol. They are negative for Voges-Proskauer, citrate utilization (17% positive), urea hydrolysis, phenylalanine deamination, arginine dihydrolase, growth in KCN, and fermentation of lactose, sucrose, myo-inositol, D-sorbitol, raffinose, and alpha-methyl-D-glucoside. By DNA hybridization (32P, 60 degrees C, hydroxyapatite), strains of E. taylorae were 84 to 95% related to the type strain (holotype) ATCC 35317. Their nearest relative was E. cloacae, to which they were 61% related. Other named species were more distantly related. Strains of E. taylorae are positive for Voges-Proskauer, citrate utilization, arginine dihydrolase, ornithine decarboxylase, motility, growth in KCN medium, and malonate utilization. They ferment D-glucose with gas production and also ferment D-mannitol, L-arabinose, L-rhamnose, maltose, D-xylose, trehalose, and cellobiose. They are negative for indole production, methyl red, H2S production on triple sugar-iron agar, urea hydrolysis, phenylalanine deamination, lysine decarboxylase, gelatin hydrolysis, and fermentation of adonitol, i-inositol, D-sorbitol, and raffinose. Both new species occur in human clinical specimens. Two strains of E. fergusonii were isolated from blood. Five stains of E. taylorae were isolated from blood, and one was

  4. Functional metagenomics unveils a multifunctional glycosyl hydrolase from the family 43 catalysing the breakdown of plant polymers in the calf rumen.

    Directory of Open Access Journals (Sweden)

    Manuel Ferrer

    Full Text Available Microbial communities from cow rumen are known for their ability to degrade diverse plant polymers at high rates. In this work, we identified 15 hydrolases through an activity-centred metagenome analysis of a fibre-adherent microbial community from dairy cow rumen. Among them, 7 glycosyl hydrolases (GHs and 1 feruloyl esterase were successfully cloned, expressed, purified and characterised. The most striking result was a protein of GH family 43 (GHF43, hereinafter designated as R_09-02, which had characteristics very distinct from the other proteins in this family with mono-functional β-xylosidase, α-xylanase, α-L-arabinase and α-L-arabinofuranosidase activities. R_09-02 is the first multifunctional enzyme to exhibit β-1,4 xylosidase, α-1,5 arabinofur(pyranosidase, β-1,4 lactase, α-1,6 raffinase, α-1,6 stachyase, β-galactosidase and α-1,4 glucosidase activities. The R_09-02 protein appears to originate from the chromosome of a member of Clostridia, a class of phylum Firmicutes, members of which are highly abundant in ruminal environment. The evolution of R_09-02 is suggested to be driven from the xylose- and arabinose-specific activities, typical for GHF43 members, toward a broader specificity to the glucose- and galactose-containing components of lignocellulose. The apparent capability of enzymes from the GHF43 family to utilise xylose-, arabinose-, glucose- and galactose-containing oligosaccharides has thus far been neglected by, or could not be predicted from, genome and metagenome sequencing data analyses. Taking into account the abundance of GHF43-encoding gene sequences in the rumen (up to 7% of all GH-genes and the multifunctional phenotype herein described, our findings suggest that the ecological role of this GH family in the digestion of ligno-cellulosic matter should be significantly reconsidered.

  5. Development of an Acid-Resistant Salmonella Typhi Ty21a Attenuated Vector For Improved Oral Vaccine Delivery

    Science.gov (United States)

    Feuille, Catherine M.; Starke, Carly Elizabeth C.; Bhagwat, Arvind A.; Stibitz, Scott; Kopecko, Dennis J.

    2016-01-01

    The licensed oral, live-attenuated bacterial vaccine for typhoid fever, Salmonella enterica serovar Typhi strain Ty21a, has also been utilized as a vaccine delivery platform for expression of diverse foreign antigens that stimulate protection against shigellosis, anthrax, plague, or human papilloma virus. However, Ty21a is acid-labile and, for effective oral immunization, stomach acidity has to be either neutralized with buffer or by-passed with Ty21a in an enteric-coated capsule (ECC). Several studies have shown that efficacy is reduced when Ty21a is administered in an ECC versus as a buffered liquid formulation, the former limiting exposure to GI tract lymphoid tissues. However, the ECC was selected as a more practical delivery format for both packaging/shipping and vaccine administration ease. We have sought to increase Ty21a acid-resistance to allow for removal from the ECC and immune enhancement. To improve Ty21a acid-resistance, glutamate-dependent acid resistance genes (GAD; responsible for Shigella spp. survival at very low pH) were cloned on a multi-copy plasmid (pGad) under a controllable arabinose-inducible promoter. pGad enhanced acid survival of Ty21a by 5 logs after 3 hours at pH 2.5, when cells were pre-grown in arabinose and under conditions that promote an acid-tolerance response (ATR). For genetically 100% stable expression, we inserted the gad genes into the Ty21a chromosome, using a method that allowed for subsequent removal of a selectable antibiotic resistance marker. Further, both bacterial growth curves and survival assays in cultured human monocytes/macrophages suggest that neither the genetic methods employed nor the resulting acid-resistance conferred by expression of the Gad proteins in Ty21a had any effect on the existing attenuation of this vaccine strain. PMID:27673328

  6. Characterization of a unique Caulobacter crescentus aldose-aldose oxidoreductase having dual activities.

    Science.gov (United States)

    Andberg, Martina; Maaheimo, Hannu; Kumpula, Esa-Pekka; Boer, Harry; Toivari, Mervi; Penttilä, Merja; Koivula, Anu

    2016-01-01

    We describe here the characterization of a novel enzyme called aldose-aldose oxidoreductase (Cc AAOR; EC 1.1.99) from Caulobacter crescentus. The Cc AAOR exists in solution as a dimer, belongs to the Gfo/Idh/MocA family and shows homology with the glucose-fructose oxidoreductase from Zymomonas mobilis. However, unlike other known members of this protein family, Cc AAOR is specific for aldose sugars and can be in the same catalytic cycle both oxidise and reduce a panel of monosaccharides at the C1 position, producing in each case the corresponding aldonolactone and alditol, respectively. Cc AAOR contains a tightly-bound nicotinamide cofactor, which is regenerated in this oxidation-reduction cycle. The highest oxidation activity was detected on D-glucose but significant activity was also observed on D-xylose, L-arabinose and D-galactose, revealing that both hexose and pentose sugars are accepted as substrates by Cc AAOR. The configuration at the C2 and C3 positions of the saccharides was shown to be especially important for the substrate binding. Interestingly, besides monosaccharides, Cc AAOR can also oxidise a range of 1,4-linked oligosaccharides having aldose unit at the reducing end, such as lactose, malto- and cello-oligosaccharides as well as xylotetraose. (1)H NMR used to monitor the oxidation and reduction reaction simultaneously, demonstrated that although D-glucose has the highest affinity and is also oxidised most efficiently by Cc AAOR, the reduction of D-glucose is clearly not as efficient. For the overall reaction catalysed by Cc AAOR, the L-arabinose, D-xylose and D-galactose were the most potent substrates.

  7. Rapid Determination of the Monosaccharide Composition and Contents in Tea Polysaccharides from Yingshuang Green Tea by Pre-Column Derivatization HPLC

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    Yujie Ai

    2016-01-01

    Full Text Available A pre-column derivatization high-performance liquid chromatography (HPLC method was developed and optimized to characterize and quantify the monosaccharides present in tea polysaccharides (TPS isolated from Yingshuang green tea. TPS sample was hydrolyzed with trifluoroacetic acid, subjected to pre-column derivatization using 1-phenyl-3-methyl-5-pyrazolone (PMP, and separated on an Agilent TC-C18 column (4.6 mm × 250 mm, 5 μm with UV detection at 250 nm. A mixture of ten PMP derivatives of standard monosaccharides (mannose, ribose, rhamnose, glucuronic acid, galacturonic acid, glucose, xylose, galactose, arabinose, and fucose could be baseline separated within 20 min. Moreover, quantitative analysis of the component monosaccharides in Yingshuang green tea TPS was achieved, indicating the TPS consisted of mannose, ribose, rhamnose, glucuronic acid, galacturonic acid, glucose, xylose, galactose, and arabinose in the molar contents of 0.72, 0.78, 0.89, 0.13, 0.15, 0.36, 0.39, 0.36, 0.36, and 0.38 μM, respectively. Recovery efficiency for component monosaccharides from TPS ranged from 93.6 to 102.4% with RSD values lower than 2.5%. In conclusion, pre-column derivatization HPLC provides a rapid, reproducible, accurate, and quantitative method for analysis of the monosaccharide composition and contents in TPS, which may help to further explore the relationship between TPS monosaccharides isolated from different tea varieties and their biological activity.

  8. Novel process for producing 6-deoxy monosaccharides from l-fucose by coupling and sequential enzymatic method.

    Science.gov (United States)

    Shompoosang, Sirinan; Yoshihara, Akihide; Uechi, Keiko; Asada, Yasuhiko; Morimoto, Kenji

    2016-01-01

    We biosynthesized 6-deoxy-L-talose, 6-deoxy-L-sorbose, 6-deoxy-L-gulose, and 6-deoxy-L-idose, which rarely exist in nature, from L-fucose by coupling and sequential enzymatic reactions. The first product, 6-deoxy-L-talose, was directly produced from L-fucose by the coupling reactions of immobilized D-arabinose isomerase and immobilized L-rhamnose isomerase. In one-pot reactions, the equilibrium ratio of L-fucose, L-fuculose, and 6-deoxy-L-talose was 80:9:11. In contrast, 6-deoxy-L-sorbose, 6-deoxy-L-gulose, and 6-deoxy-L-idose were produced from L-fucose by sequential enzymatic reactions. D-Arabinose isomerase converted L-fucose into L-fuculose with a ratio of 88:12. Purified L-fuculose was further epimerized into 6-deoxy-L-sorbose by D-allulose 3-epimerase with a ratio of 40:60. Finally, purified 6-deoxy-L-sorbose was isomerized into both 6-deoxy-L-gulose with an equilibrium ratio of 40:60 by L-ribose isomerase, and 6-deoxy-L-idose with an equilibrium ratio of 73:27 by D-glucose isomerase. Based on the amount of L-fucose used, the production yields of 6-deoxy-L-talose, 6-deoxy-L-sorbose, 6-deoxy-L-gulose, and 6-deoxy-L-idose were 7.1%, 14%, 2%, and 2.4%, respectively.

  9. Molecular cloning of a bifunctional beta-xylosidase/alpha-L-arabinosidase from alfalfa roots: heterologous expression in Medicago truncatula and substrate specificity of the purified enzyme.

    Science.gov (United States)

    Xiong, Jin-Song; Balland-Vanney, Maud; Xie, Zhi-Ping; Schultze, Michael; Kondorosi, Adam; Kondorosi, Eva; Staehelin, Christian

    2007-01-01

    Glycoside hydrolases are often members of a multigene family, suggesting individual roles for each isoenzyme. Various extracellular glycoside hydrolases have an important but poorly understood function in remodelling the cell wall during plant growth. Here, MsXyl1, a concanavalin A-binding protein from alfalfa (Medicago sativa L.) belonging to the glycoside hydrolase family 3 (beta-D-xylosidase branch) is characterized. Transcripts of MsXyl1 were detected in roots (particularly root tips), root nodules, and flowers. MsXyl1 under the control of the CaMV 35S promoter was expressed in the model legume Medicago truncatula (Gaertner). Concanavalin A-binding proteins from the transgenic plants exhibited 5-8-fold increased activities towards three p-nitrophenyl (PNP) glycosides, namely PNP-beta-D-xyloside, PNP-alpha-L-arabinofuranoside, and PNP-alpha-L-arabinopyranoside. An antiserum raised against a synthetic peptide recognized MsXyl1, which was processed to a 65 kDa form. To characterize the substrate specificity of MsXyl1, the recombinant protein was purified from transgenic M. truncatula leaves by concanavalin A and anion chromatography. MsXyl1cleaved beta-1,4-linked D-xylo-oligosaccharides and alpha-1,5-linked L-arabino-oligosaccharides. Arabinoxylan (from wheat) and arabinan (from sugar beet) were substrates for MsXyl1, whereas xylan (from oat spelts) was resistant to degradation. Furthermore, MsXyl1 released xylose and arabinose from cell wall polysaccharides isolated from alfalfa roots. These data suggest that MsXyl1 is a multifunctional beta-xylosidase/alpha-L-arabinofuranosidase/alpha-L-arabinopyranosidase implicated in cell wall turnover of arabinose and xylose, particularly in rapidly growing root tips. Moreover, the findings of this study demonstrate that stable transgenic M. truncatula plants serve as an excellent expression system for purification and characterization of proteins.

  10. 高产D-塔格糖植物乳杆菌WU14的筛选与鉴定

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    D-tagatose is a kind of natural sweetener with low-calorie.L-arabinose isomerase is the key enzyme for D-galactose isomerization to D-tagatose by biological method.In this study lactic acid bacteria strains were isolated from pickled vegetables and pickled cabbage.A lactic acid bacteria strain with high yield of D-tagatose was screened by the thin layer chromatography and modified cysteine carbazole method from the lactic acid bacteria strains and its L-arabinose isomerase activity was 13.95 U/mL after analysed.This strain was named Lactobacillus plantarum WU14 based on the se-quence analysis of 16S rDNA and biochemical characteristics.The result of this study could lay the foundation for the bio-conversion D-tagatose industrial production.%D-塔格糖是一种天然低热量甜味剂。 L-阿拉伯糖异构酶(L-AI)是生物法异构化D-半乳糖为D-塔格糖的关键酶。本研究从腌菜和泡菜中分离出一批乳酸菌,经薄层色谱法初筛和改良半胱氨酸咔唑法复筛,获得一株高产D-塔格糖的乳酸菌,其发酵粗酶液中L-阿拉伯糖异构酶酶活达13.95 U/mL,经16S rDNA序列比对及生化特征分析,该菌被鉴定并命名为Lactobacillus plantarum WU14。研究结果可为生物转化D-塔格糖达到工业化生产奠定基础。

  11. O-glycans and O-glycosylation sites of recombinant human GM-CSF derived from suspension-cultured rice cells, and their structural role.

    Science.gov (United States)

    Kim, Jihye; Park, Heajin; Park, Byung Tae; Hwang, Hye Seong; Kim, Jae Il; Kim, Dae Kyong; Kim, Ha Hyung

    2016-10-14

    Recombinant human GM-CSF (rhGM-CSF) from yeast has been clinically applied to immunosuppressed patients. The production of suspension-cultured rice-cell-derived rhGM-CSF (rrhGM-CSF), which has a longer blood clearance time and the same bioactivity as yeast-derived rhGM-CSF, and the analysis of its N-glycans have been reported recently. However, there are no previous reports of the O-glycosylation of rhGM-CSF from plant cells, and so this study investigated O-glycans, O-glycosylation sites, and their structural role in rrhGM-CSF. Monosaccharide analysis revealed the presence of O-glycans comprising arabinose and galactose. Eight O-glycans comprising four arabinose residues with zero to seven galactose residues along with their relative quantities were analyzed. Analysis of pronase-digested glycopeptides indicated that the O-glycans are partially attached to Ser 5, Ser 7, Ser 9, or Thr 10 residues, and glycan heterogeneity was confirmed at each site. Pro-to-hydroxyproline conversions occurred at Pro 2, Pro 6, and Pro 8 residues. The preparation of deglycosylated rrhGM-CSFs revealed that deglycosylation greatly affects their α-helix structures. These findings indicate that O-glycans of rrhGM-CSF are essential for maintaining its structural stability and result in an extended in vivo half-life, but without affecting its biological function. This is the first report on the O-glycosylation of rhGM-CSF derived from plant cells.

  12. The Effect of pH Control on Acetone-Butanol-Ethanol Fermentation by Clostridium acetobutylicum ATCC 824 with Xylose and D-Glucose and D-Xylose Mixture

    Institute of Scientific and Technical Information of China (English)

    Wei Jiang; Zhiqiang Wen; Mianbin Wu; Hong Li; Jun Yang; Jianping Lin; Yijun Lin; Lirong Yang; Peilin Cen

    2014-01-01

    D-Glucose, L-arabinose, D-mannose, D-xylose, and cellobiose are saccharification products of lignocellulose and important carbon sources for industrial fermentation. The fermentation efficiency with each of the five sugars and the mixture of the two most dominant sugars, D-glucose and D-xylose, was evaluated for acetone-butanol-ethanol (ABE) fermentation by Clostridium acetobutylicum ATCC 824. The utilization efficacy of the five reducing sugars was in the order of D-glucose, L-arabinose, D-mannose, D-xylose and cellobiose. D-Xylose, the second most abundant component in lignocellulosic hydrolysate, was used in the fermentation either as sole carbon source or mixed with glucose. The results indicated that maintaining pH at 4.8, the optimal pH value for solventogenesis, could increase D-xylose consumption when it was the sole carbon source. Different media con-taining D-glucose and D-xylose at different ratios (1:2, 1:5, 1.5:1, 2:1) were then attempted for the ABE fermenta-tion. When pH was at 4.8 and xylose concentration was five times that of glucose, a 256.9%increase in xylose utilization and 263.7%increase in solvent production were obtained compared to those without pH control. These results demonstrate a possible approach combining optimized pH control and D-glucose and D-xylose ratio to increase the fermentation efficiency of lignocellulosic hydrolysate.

  13. Transfer of the first arabinofuranose residue to galactan is essential for Mycobacterium smegmatis viability.

    Science.gov (United States)

    Shi, Libin; Zhou, Roukun; Liu, Zhentong; Lowary, Todd L; Seeberger, Peter H; Stocker, Bridget L; Crick, Dean C; Khoo, Kay-Hooi; Chatterjee, Delphi

    2008-08-01

    The mycobacterial arabinan is an elaborate component of the cell wall with multiple glycosyl linkages and no repeating units. In Mycobacterium spp., the Emb proteins (EmbA, EmbB, and EmbC) have been identified as putative mycobacterial arabinosyltransferases implicated in the biogenesis of the cell wall arabinan. Furthermore, it is now evident that the EmbA and EmbB proteins are involved in the assembly of the nonreducing terminal motif of arabinogalactan and EmbC is involved in transferring arabinose, perhaps in the early stage of arabinan synthesis in lipoarabinomannan. It has also been shown that the Emb proteins are a target of the antimycobacterial drug ethambutol (EMB). In the search for additional mycobacterial arabinosyltransferases in addition to the Emb proteins, we disrupted MSMEG_6386 (an orthologue of Rv3792 and a gene upstream of embC) in Mycobacterium smegmatis. Allelic exchange at the chromosomal MSMEG_6386 locus of M. smegmatis could only be achieved in the presence of a rescue plasmid carrying a functional copy of MSMEG_6386 or Rv3792, strongly suggesting that MSMEG_6386 is essential. An in vitro arabinosyltransferase assay using a membrane preparation from M. smegmatis expressing Rv3792 and synthetic beta-d-Galf-(1-->5)-beta-D-Galf-(1-->6)-beta-D-Galf-octyl and beta-D-Galf-(1-->6)-beta-D-Galf-(1-->5)-beta-D-Galf-octyl showed that Rv3792 gene product can transfer an arabinose residue to the C-5 position of the internal 6-linked galactose. The reactions were insensitive to EMB, and when alpha-d-Manp-(1-->6)-alpha-D-Manp-(1-->6)-alpha-D-Manp-octylthiomethyl was used as an acceptor, no product was formed. These observations indicate that transfer of the first arabinofuranose residue to galactan is essential for M. smegmatis viability.

  14. Identification of a novel arabinofuranosyltransferase (AftA) involved in cell wall arabinan biosynthesis in Mycobacterium tuberculosis.

    Science.gov (United States)

    Alderwick, Luke J; Seidel, Mathias; Sahm, Hermann; Besra, Gurdyal S; Eggeling, Lothar

    2006-06-09

    The cell wall mycolyl-arabinogalactan-peptidoglycan complex is essential in mycobacterial species, such as Mycobacterium tuberculosis, and is the target of several anti-tubercular drugs. For instance, ethambutol targets arabinogalactan biosynthesis through inhibition of the arabinofuranosyltransferases Mt-EmbA and Mt-EmbB. Following a detailed bioinformatics analysis of genes surrounding the conserved emb locus, we present the identification and characterization of a novel arabinofuranosyltransferase AftA (Rv3792). The enzyme catalyzes the addition of the first key arabinofuranosyl residue from the sugar donor beta-D-arabinofuranosyl-1-monophosphoryldecaprenol to the galactan domain of the cell wall, thus "priming" the galactan for further elaboration by the arabinofuranosyltransferases. Because aftA is an essential gene in M. tuberculosis, we deleted its orthologue in Corynebacterium glutamicum to produce a slow growing but viable mutant. Analysis of its cell wall revealed the complete absence of arabinose resulting in a truncated cell wall structure possessing only a galactan core with a concomitant loss of cell wall-bound mycolates. Complementation of the mutant was fully restored to the wild type phenotype by Cg-aftA. In addition, by developing an in vitro assay using recombinant Escherichia coli expressing Mt-aftA and use of cell wall galactan as an acceptor, we demonstrated the transfer of arabinose from beta-D-arabinofuranosyl-1-monophosphoryldecaprenol to galactan, and unlike the Mt-Emb proteins, Mt-AftA was not inhibited by ethambutol. This newly discovered glycosyltransferase represents an attractive drug target for further exploitation by chemotherapeutic intervention.

  15. Characterization and biological effects of two polysaccharides isolated from Acanthopanax sciadophylloides.

    Science.gov (United States)

    Lee, Jung-Bum; Tanikawa, Tatsuya; Hayashi, Kyoko; Asagi, Mariko; Kasahara, Yoshimasa; Hayashi, Toshimitsu

    2015-02-13

    Two polysaccharides abbreviated ANP and AAP were isolated from the young buds of Acanthopanax sciadophylloides. ANP consisted of L-arabinose, D-mannose, D-glucose and D-galactose in a ratio of ca 1.0:2.6:2.5:1.4 and its weight average molecular weight (Mw) was 1.07×10(4). AAP consisted of L-arabinose, D-galactose and 4-O-methyl-D-glucuronic acid in a ratio of ca 5:10:1, and its Mw was estimated to be 8.40×10(4). ANP was suggested to be an acetylated heteropolysaccharide, whereas AAP was speculated to be a type II arabinogalactan on the basis of structural analysis data. Both polysaccharides were found to stimulate NO production and induce the expression of cytokine mRNAs including IL-1β, IL-6, IL-10 and TNF-α on RAW264.7 cells. They also induced NF-κB activation in RAW-Blue cells. NO production and NF-κB activation by both polysaccharides were decreased by pretreatment with neutralizing anti-TLR-4 and anti-CD14 antibodies but not with anti-TLR-2, anti-SR-A, anti-CD11c, and anti-Dectin-1 antibodies. Therefore, these immunostimulating effects of ANP and AAP were suggested to be promoted by the interaction through the membrane receptors, TLR-4 and CD14. In addition to immunomodulating effects, ANP showed anti-HSV-2 effects in vitro.

  16. Extraction, Isolation, Structural Characterization and Anti-Tumor Properties of an Apigalacturonan-Rich Polysaccharide from the Sea Grass Zostera caespitosa Miki

    Directory of Open Access Journals (Sweden)

    Youjing Lv

    2015-06-01

    Full Text Available An apigalacturonan (AGA-rich polysaccharide, ZCMP, was isolated from the sea grass Zostera caespitosa Miki. The depolymerized fragments derived from ZCMP were obtained by either acidic degradation or pectinase degradation, and their structures were characterized by electrospray ionization collision-induced-dissociation mass spectrometry (ESI-CID-MS2 and nuclear magnetic resonance (NMR spectroscopy. The average molecular weight of ZCMP was 77.2 kD and it consisted of galacturonic acid (GalA, apiosefuranose (Api, galactose (Gal, rhamnose (Rha, arabinose (Ara, xylose (Xyl, and mannose (Man, at a molar ratio of 51.4꞉15.5꞉6.0꞉11.8꞉4.2꞉4.4꞉4.2. There were two regions of AGA (70% and rhamnogalacturonan-I (RG-Ι, 30% in ZCMP. AGA was composed of an α-1,4-D-galactopyranosyluronan backbone mainly substituted at the O-3 position by single Api residues. RG-Ι possessed a backbone of repeating disaccharide units of →4GalAα1,2Rhaα1→, with a few α-L-arabinose and β-D-galactose residues as side chains. The anti-angiogenesis assay showed that ZCMP inhibited the migratory activity of human umbilical vein endothelial cell (HUVECs, with no influence on endothelial cells growth. ZCMP also promoted macrophage phagocytosis. These findings of the present study demonstrated the potential anti-tumor activity of ZCMP through anti-angiogenic and immunoregulatory pathways.

  17. Pretreatment of Dried Distiller Grains with Solubles by Soaking in Aqueous Ammonia and Subsequent Enzymatic/Dilute Acid Hydrolysis to Produce Fermentable Sugars.

    Science.gov (United States)

    Nghiem, Nhuan P; Montanti, Justin; Kim, Tae Hyun

    2016-05-01

    Dried distillers grains with solubles (DDGS), a co-product of corn ethanol production in the dry-grind process, was pretreated by soaking in aqueous ammonia (SAA) using a 15 % w/w NH4OH solution at a solid/liquid ratio of 1:10. The effect of pretreatment on subsequent enzymatic hydrolysis was studied at two temperatures (40 and 60 °C) and four reaction times (6, 12, 24, and 48 h). Highest glucose yield of 91 % theoretical was obtained for the DDGS pretreated at 60 °C and 24 h. The solubilized hemicellulose in the liquid fraction was further hydrolyzed with dilute H2SO4 to generate fermentable monomeric sugars. The conditions of acid hydrolysis included 1 and 4 wt% acid, 60 and 120 °C, and 0.5 and 1 h. Highest yields of xylose and arabinose were obtained at 4 wt% acid, 120 °C, and 1 h. The fermentability of the hydrolysate obtained by enzymatic hydrolysis of the SAA-pretreated DDGS was demonstrated in ethanol fermentation by Saccharomyces cerevisiae. The fermentability of the hydrolysate obtained by consecutive enzymatic and dilute acid hydrolysis was demonstrated using a succinic acid-producing microorganism, strain Escherichia coli AFP184. Under the fermentation conditions, complete utilization of glucose and arabinose was observed, whereas only 47 % of xylose was used. The succinic acid yield was 0.60 g/g total sugar consumed.

  18. Monosaccharide composition of Herniaria glabra L. and Herniaria polygama J.Gay

    Directory of Open Access Journals (Sweden)

    Kozachok Solomiia

    2016-09-01

    Full Text Available The plants from Herniaria genus (Caryophyllaceae family are mainly applied as diuretic agents for the treatment of kidney and gall-stones, gouts, urinary tract infections, hypertension and diabetes. The most widely spread species in Europe is Herniaria glabra L. (HG. Herniaria polygama J.Gay (HP is found growing from Eastern Europe to Asia. Surprisingly, no work has been reported on the analysis of primary metabolites of HP yet and there is only a limited data on HG. The aim of our study was to establish the monosaccharide composition after a complete hydrolysis and in a free state in the entire herbs of HG and HP harvested in the western and central parts of Ukraine. The carbohydrates were separated by gas chromatography-mass spectrometry after conversion into volatile derivatives as aldononitrile acetate. As a result, the monosaccharide composition after a total hydrolysis was established with the contribution of the following components: D-rhamnose, D-arabinose, D-fucose, D-xylose, D-manose, D-glucose, D-galactose, D-pinitol, myo-inisitol, D-mannitol, D-dulcitol. In a free state it was detected: D-fructose, D-glucose, D-galactose, D-pinitol, myo-inisitol, D-mannitol and D-saccharose. The following monosaccharides were found in the most abundant quantities in HG and HP respectively: glucose was determined as the major component – 33.40 and 22.80 mg/g, the second dominant sugar was pinitol – 16.80 and 18.07 mg/g, followed by galactose – 13.88 mg/g in HG and arabinose – 8.13 mg/g in HP. Sugars were determined in these plant species for the first time and this finding shed new light on their pharmacological application.

  19. Compositional changes in cell wall polysaccharides from apple fruit callus cultures modulated by different plant growth regulators.

    Science.gov (United States)

    Alayón-Luaces, Paula; Ponce, Nora M A; Mroginski, Luis A; Stortz, Carlos A; Sozzi, Gabriel O

    2012-04-01

    The cell wall composition of apples callus cultures showed changes in the presence of 5 mg l(-1) of three different plant growth regulators (PGRs), namely picloram, abscisic acid and gibberellic acid. Although the structural functions of cell walls do not generally allow for pronounced variations of the total pectin and matrix glycan content, this work provides evidence that the addition of these plant growth regulators can rule, at least partly, cell wall metabolism in apple callus cultures. The chelator- and carbonate-extracts always had the analytical characteristics of pectins, with high proportions of uronic acids, arabinose and galactose as the main monosaccharides, and a significant proportion of rhamnose, but the cross-linking glycan fractions were still rich in RG-I-like material. The application of PGRs produced shifts of uronic acid and neutral sugars between fractions. Arabinose was the neutral sugar exhibiting more variations in apple callus cell wall. Picloram and abscisic acid produced an increase of the uronic acid contents of the cell walls. The AIRs obtained from calluses treated with different PGRs did not show large amounts of high molecular weight products, as determined by size-exclusion chromatography. For the carbonate-extract only the callus treated with picloram displayed two separated peaks for products of different molecular weights. The chromatographic profiles for the 4% KOH-extract displayed two peaks for all the treatments, one very sharp with high molecular weight, and another one wider of smaller molecular weight, whereas the difference between treatments can only be appraised through the areas of the peaks. This is the first report on cell wall composition from fruit calluses supplemented with different PGRs.

  20. CARACTERIZAÇÃO BIOQUÍMICA DE AMOSTRAS DE Haemophilus parasuis ISOLADAS DE SUÍNOS NA REGIÃO SUL DO BRASIL

    Directory of Open Access Journals (Sweden)

    Maria Aparecida Vasconcelos Paiva Brito

    1994-12-01

    Full Text Available O objetivo deste trabalho foi caracterizar amostras não hemolíticas de bactérias do gênero Haemophilus isoladas de suínos. As bactérias foram isoladas de material clínico de animais com suspeita da doença de Glässer, de leitões aparentemente sadios provenientes de quatro rebanhos com suspeita clínica desta doença e de casos de poliartrites. Além das características culturais e morfotintoriais, foram utilizados os seguintes testes para a identificação: dependência de NAD(fator V, CAMP, produção de hemolisina, indol, urease e catalase, redução do nitrato e produção de ácido dos carboidratos: glicose, sacarose, arabinose e manose. Dezessete dentre 24 amostras foram classificadas como Haemophilus parasuis (dez isoladas de animais clinicamente doentes e sete de leitões normais. Cinco destas amostras foram classificadas nos sorogrupos 2, 4, 7, ND4 e uma foi não tipável. Quatro das 24 amostras apresentaram características do grupo taxonômico C (teste de arabinose positivo e três produziram urease. Os testes realizados não permitiram distinguir as amostras urease positivas do gênero Haemophilus das amostras não hemolíticas de Actinobacilius pleuropneumoniae. Mais de 60% das amostras apresentaram sensibilidade in vitro a: ampicilina, cefalotina, cloranfenicol, danofioxacina, nitrofurantoína, penicilina G, polimixina B e tetraciclina.

  1. Burkholderia pseudomallei virulence: definition, stability and association with clonality.

    Science.gov (United States)

    Ulett, G C; Currie, B J; Clair, T W; Mayo, M; Ketheesan, N; Labrooy, J; Gal, D; Norton, R; Smith, C A; Barnes, J; Warner, J; Hirst, R G

    2001-07-01

    Clinical presentations of melioidosis, caused by Burkholderia pseudomallei are protean, but the mechanisms underlying development of the different forms of disease remain poorly understood. In murine melioidosis, the level of virulence of B. pseudomallei is important in disease pathogenesis and progression. In this study, we used B. pseudomallei-susceptible BALB/c mice to determine the virulence of a library of clinical and environmental B. pseudomallei isolates from Australia and Papua New Guinea. Among 42 non-arabinose-assimilating (ara(-)) isolates, LD(50) ranged from 10 to > 10(6) CFU. There were numerous correlations between virulence and disease presentation in patients; however, this was not a consistent observation. Virulence did not correlate with isolate origin (i.e. clinical vs environmental), since numerous ara(-) environmental isolates were highly virulent. The least virulent isolate was a soil isolate from Papua New Guinea, which was arabinose assimilating (ara(+)). Stability of B. pseudomallei virulence was investigated by in vivo passage of isolates through mice and repetitive in vitro subculture. Virulence increased following in vivo exposure in only one of eight isolates tested. In vitro subculture on ferric citrate-containing medium caused attenuation of virulence, and this correlated with changes in colony morphology. Pulsed-field gel electrophoresis and randomly amplified polymorphic DNA typing demonstrated that selected epidemiologically related isolates that had variable clinical outcomes and different in vivo virulence were clonal strains. No molecular changes were observed in isolates after in vivo or in vitro exposure despite changes in virulence. These results indicate that virulence of selected B. pseudomallei isolates is variable, being dependent on factors such as iron bioavailability. They also support the importance of other variables such as inoculum size and host risk factors in determining the clinical severity of melioidosis.

  2. Metabolic Studies on Intermediates in the myo-Inositol Oxidation Pathway in Lilium longiflorum Pollen: I. Conversion to Hexoses.

    Science.gov (United States)

    Rosenfield, C L; Fann, C; Loewus, F A

    1978-01-01

    The myo-inositol oxidation pathway was investigated in regard to its role as a source of carbon for products of hexose monophosphate metabolism in germinated pollen of Lilium longiflorum Thunb., cv. Ace. myo-[2-(14)]Inositol and d-[1-(14)C]glucuronate had similar distributions of radioactivity, contributing about three times more label to polysaccharide-bound glucose than myo-[2-(3)H]inositol. In the course of glucogenesis label from the latter appeared as tritiated water in the medium. This exchange could be enhanced by supplying d-[5R,5S-(3)H]xylose instead of myo-[2-(3)H]inositol. When the former was administered, [(3)H]glucose was the only labeled sugar residue found in polysaccharide products. The soluble constituents of d-[5R,5S-(3)H]xylose-labeled pollen contained no traces of labeled xylose despite massive uptake and utilization.l-[1-(14)C]- and l-[5-(14)C]Arabinose produced similar labeling patterns in germinated pollen including incorporation of arabinosyl units into pollen tube polysaccharides and substantial glucogenesis which led to utilization of arabinose for respiration and further incorporation of labeled glucosyl units into pollen tube polysaccharides.d-[5-(3)H]Galacturonate was rapidly taken up by germinated pollen but slowly utilized, without conversion to other sugars, for incorporation into pollen tube polysaccharides. l-[6-(14)C]Gulonate was not taken up by pollen.Results strongly support a scheme of conversion from myo-inositol to hexose monophosphate and subsequent products of glucose metabolism that involves the myo-inositol oxidation pathway.

  3. Salmonella enterica serovar typhimurium strains with regulated delayed attenuation in vivo.

    Science.gov (United States)

    Curtiss, Roy; Wanda, Soo-Young; Gunn, Bronwyn M; Zhang, Xin; Tinge, Steven A; Ananthnarayan, Vidya; Mo, Hua; Wang, Shifeng; Kong, Wei

    2009-03-01

    Recombinant bacterial vaccines must be fully attenuated for animal or human hosts to avoid inducing disease symptoms while exhibiting a high degree of immunogenicity. Unfortunately, many well-studied means for attenuating Salmonella render strains more susceptible to host defense stresses encountered following oral vaccination than wild-type virulent strains and/or impair their ability to effectively colonize the gut-associated and internal lymphoid tissues. This thus impairs the ability of recombinant vaccines to serve as factories to produce recombinant antigens to induce the desired protective immunity. To address these problems, we designed strains that display features of wild-type virulent strains of Salmonella at the time of immunization to enable strains first to effectively colonize lymphoid tissues and then to exhibit a regulated delayed attenuation in vivo to preclude inducing disease symptoms. We recently described one means to achieve this based on a reversible smooth-rough synthesis of lipopolysaccharide O antigen. We report here a second means to achieve regulated delayed attenuation in vivo that is based on the substitution of a tightly regulated araC P(BAD) cassette for the promoters of the fur, crp, phoPQ, and rpoS genes such that expression of these genes is dependent on arabinose provided during growth. Thus, following colonization of lymphoid tissues, the Fur, Crp, PhoPQ, and/or RpoS proteins cease to be synthesized due to the absence of arabinose such that attenuation is gradually manifest in vivo to preclude induction of diseases symptoms. Means for achieving regulated delayed attenuation can be combined with other mutations, which together may yield safe efficacious recombinant attenuated Salmonella vaccines.

  4. Fine-tuning synthesis of Yersinia pestis LcrV from runaway-like replication balanced-lethal plasmid in a Salmonella enterica serovar typhimurium vaccine induces protection against a lethal Y. pestis challenge in mice.

    Science.gov (United States)

    Torres-Escobar, Ascención; Juárez-Rodríguez, María Dolores; Gunn, Bronwyn M; Branger, Christine G; Tinge, Steven A; Curtiss, Roy

    2010-06-01

    A balanced-lethal plasmid expression system that switches from low-copy-number to runaway-like high-copy-number replication (pYA4534) was constructed for the regulated delayed in vivo synthesis of heterologous antigens by vaccine strains. This is an antibiotic resistance-free maintenance system containing the asdA gene (essential for peptidoglycan synthesis) as a selectable marker to complement the lethal chromosomal DeltaasdA allele in live recombinant attenuated Salmonella vaccines (RASVs) such as Salmonella enterica serovar Typhimurium strain chi9447. pYA4534 harbors two origins of replication, pSC101 and pUC (low and high copy numbers, respectively). The pUC replication origin is controlled by a genetic switch formed by the operator/promoter of the P22 cro gene (O/P(cro)) (P(R)), which is negatively regulated by an arabinose-inducible P22 c2 gene located on both the plasmid and the chromosome (araC P(BAD) c2). The absence of arabinose, which is unavailable in vivo, triggers replication to a high-copy-number plasmid state. To validate these vector attributes, the Yersinia pestis virulence antigen LcrV was used to develop a vaccine against plague. An lcrV sequence encoding amino acids 131 to 326 (LcrV196) was optimized for expression in Salmonella, flanked with nucleotide sequences encoding the signal peptide (SS) and the carboxy-terminal domain (CT) of beta-lactamase, and cloned into pYA4534 under the control of the P(trc) promoter to generate plasmid pYA4535. Our results indicate that the live Salmonella vaccine strain chi9447 harboring pYA4535 efficiently stimulated a mixed Th1/Th2 immune response that protected mice against lethal challenge with Y. pestis strain CO92 introduced through either the intranasal or subcutaneous route.

  5. Yersinia pestis with regulated delayed attenuation as a vaccine candidate to induce protective immunity against plague.

    Science.gov (United States)

    Sun, Wei; Roland, Kenneth L; Kuang, Xiaoying; Branger, Christine G; Curtiss, Roy

    2010-03-01

    Two mutant strains of Yersinia pestis KIM5+, a Deltacrp mutant and a mutant with arabinose-dependent regulated delayed-shutoff crp expression (araC P(BAD) crp), were constructed, characterized in vitro, and evaluated for virulence, immunogenicity, and protective efficacy in mice. Both strains were highly attenuated by the subcutaneous (s.c.) route. The 50% lethal doses (LD(50)s) of the Deltacrp and araC P(BAD) crp mutants were approximately 1,000,000-fold and 10,000-fold higher than those of Y. pestis KIM5+, respectively, indicating that both strains were highly attenuated. Mice vaccinated s.c. with 3.8 x 10(7) CFU of the Deltacrp mutant developed high anti-Y. pestis and anti-LcrV serum IgG titers, both with a strong Th2 bias, and induced protective immunity against subcutaneous challenge with virulent Y. pestis (80% survival) but no protection against pulmonary challenge. Mice vaccinated with 3.0 x 10(4) CFU of the araC P(BAD) crp mutant also developed high anti-Y. pestis and anti-LcrV serum IgG titers but with a more balanced Th1/Th2 response. This strain induced complete protection against s.c. challenge and partial protection (70% survival) against pulmonary challenge. Our results demonstrate that arabinose-dependent regulated crp expression is an effective strategy to attenuate Y. pestis while retaining strong immunogenicity, leading to protection against the pneumonic and bubonic forms of plague.

  6. Arabino-galactan proteins from Pistacia lentiscus var. chia: isolation, characterization and biological function.

    Science.gov (United States)

    Kottakis, F; Lamari, F; Matragkou, Ch; Zachariadis, G; Karamanos, N; Choli-Papadopoulou, T

    2008-04-01

    Arabino-Galactan Proteins (AGPs) were isolated from Chios mastic gum (CMG) by using a buffer containing 0.1 M NaCl, 20 mM Tris-HCl, pH 7.5. Protein analytical methods, combined with specific procedures for carbohydrate characterization, indicated the presence of highly glycosylated protein backbone. In particular, staining by Yariv reagent of the electrophoretically separated molecules revealed the existence of arabinose and galactose and such a modification is characteristic for AGPs. After experiments involving extensive dialysis of the isolated extracts against water and atomic absorption, there was evidence of the existence of zinc ions that are probably covalently bound to the AGPs. By using anion-exchange chromatography, capillary electrophoresis, colorimetric methods and GC-MS, it was found that the extracts were separated into three major populations (A, B, and C), which were consistent with their respective negative charge content namely, uronic acid. The characterization of neutral sugars that was investigated with GC-MS showed the existence of arabinose and galactose in different amounts for each group. Experiments concerning the inhibition of growth of Helicobacter pylori in the presence of AGPs, as is shown for other CMG constituents, showed that the extracts of at least 1.4 g CMG affected the viability of the bacterium. There is no evidence as to whether the AGPs provoke abnormal morphologies of H. pylori, as is reported for the total CMG, or for O-glycans that possess terminal alpha1, 4-linked N-acetylglucosamine and are expressed in the human gastric mucosa; this has to be further investigated.

  7. Selective chemical oxidation and depolymerization of switchgrass [corrected] (Panicum virgatum L.) xylan with [corrected] oligosaccharide product analysis by mass spectrometry.

    Science.gov (United States)

    Bowman, Michael J; Dien, Bruce S; O'Bryan, Patricia J; Sarath, Gautam; Cotta, Michael A

    2011-04-15

    Xylan is a barrier to enzymatic hydrolysis of plant cell walls. It is well accepted that the xylan layer needs to be removed to efficiently hydrolyze cellulose; consequently, pretreatment conditions are (in part) optimized for maximal xylan depolymerization or displacement. Xylan consists of a long chain of β-1,4-linked xylose units substituted with arabinose (typically α-1,3-linked in grasses) and glucuronic acid (α-1,2-linked). Xylan has been proposed to have a structural function in plants and therefore may play a role in determining biomass reactivity to pretreatment. It has been proposed that substitutions along xylan chains are not random and, based upon studies of pericarp xylan, are organized in domains that have specific structural functions. Analysis of intact xylan is problematic because of its chain length (> degree of polymerization (d.p.) 100) and heterogeneous side groups. Traditionally, enzymatic end-point products have been characterized due to the limited products generated. Analysis of resultant arabino-xylo-oligosaccharides by mass spectrometry is complicated by the isobaric pentose sugars that primarily compose xylan. In this report, the variation in pentose ring structures was exploited for selective oxidation of the arabinofuranose primary alcohols followed by acid depolymerization to provide oligosaccharides with modified arabinose branches intact. Switchgrass samples were analyzed by hydrophilic interaction chromatography (HILIC)-liquid chromatography (LC)-mass spectrometry/mass spectrometry (MSMS) and off-line nanospray MS to demonstrate the utility of this chemistry for determination of primary hydroxyl groups on oligosaccharide structures, with potential applications for determining the sequence of arabino-xylo-oligosaccharides present in plant cell wall material.

  8. The use of triphenyltetrazolium chloride in the study of dehydrogenase activity of Brucellae O emprêgo do cloreto de trifeniltetrazólio no estudo da atividade dehidrogenásica de brucelas

    Directory of Open Access Journals (Sweden)

    Milton Thiago de Mello

    1955-05-01

    Full Text Available Experiments for the investigation of dehydrogenase activity of washed cells of a strains of Br. abortus and another of Br. suis in presence of different single added substrates are reported. The activity was measured as the amount of formazan produced by the reduction of 2, 3, 5-triphenyltetrazolum chloride acting as a hydrogen ions acceptor, at pH 7.0. In a general manner the dehydrogenase activity of Br. suis was much more intense than that of Br. abortus (fig. 5. In the conditions of the experiments Br. abortus oxidized L-arabinose, D-galactose, D-glucose, glycerol, D-xylose, DL-alanine, D-fructose, and D-sorbitol. Brucella suis oxidized D-xylose, L-arabinose, D-glucose, D-galactose, DL-alanine, sodium acetate, maltose, glycine, D-fructose, and D-sorbitol. Glycerol was oxidized by Br. abortus but its oxidation by Br. suir was very slight. Sodium acetate and maltose were intensely oxidized by Br. suir but not by Br. abortus. The sites of more intense enzymatic acitivity were seen as small red colored round granules located in one pole of the cells.Com a finalidade de observar a atividade dhidrogenásica de brucelas, em presença de diversos substratos isolados, empregamos o cloreto de trifeniltetrazólio (em solução aquosa a 0,1% como receptor de hidrogênio. Os substratos (em solução aquosa M 50 foram os seguintes: Hidratos de carbono: L-arabinose, D-frutose, D-galactose, D-glucose, D-lactose, matose e D-xilose; alcoóis: glicerol, L-inositol, D-manitol e D-sobitol; ácidos aminados: ácido D-glutâmico, D-arginina, DL-alanina, L-asparagina e glicina; acetato de sódio. Empregamos suspensões de culturas de 48 horas de duas amostras típicas: Brucella abortus (aeróbica, nº 1 868, amostra B-99, Weybridge e Br. suis (nº 1 568, amostra SIG do Dr. S. S. Elberg, da Universidade de Califórnia. As culturas em agar, lavadas 5 vêzes em solução de cloreto de sódio a 0,9% ("resting cells" foram suspensas nessas solução salina de maneira a

  9. Comparison of different pretreatment methods for separation hemicellulose from straw during the lignocellulosic bioethanol production

    Science.gov (United States)

    Eisenhuber, Katharina; Krennhuber, Klaus; Steinmüller, Viktoria; Kahr, Heike; Jäger, Alexander

    2013-04-01

    The combustion of fossil fuels is responsible for 73% of carbon dioxide emissions into the atmosphere and consequently contributes to global warming. This fact has enormously increased the interest in the development of methods to reduce greenhouse gases. Therefore, the focus is on the production of biofuels from lignocellulosic agricultural residues. The feedstocks used for 2nd generation bioethanol production are lignocellulosic raw materials like different straw types or energy crops like miscanthus sinensis or arundo donax. Lignocellulose consists of hemicellulose (xylose and arabinose), which is bonded to cellulose (glucose) and lignin. Prior to an enzymatic hydrolysis of the polysaccharides and fermentation of the resulting sugars, the lignocelluloses must be pretreated to make the sugar polymers accessible to enzymes. A variety of pretreatment methods are described in the literature: thermophysical, acid-based and alkaline methods.In this study, we examined and compared the most important pretreatment methods: Steam explosion versus acid and alkaline pretreatment. Specific attention was paid to the mass balance, the recovery of C 5 sugars and consumption of chemicals needed for pretreatment. In lab scale experiments, wheat straw was either directly pretreated by steam explosion or by two different protocols. The straw was either soaked in sulfuric acid or in sodium hydroxide solution at different concentrations. For both methods, wheat straw was pretreated at 100°C for 30 minutes. Afterwards, the remaining straw was separated by vacuum filtration from the liquid fraction.The pretreated straw was neutralized, dried and enzymatically hydrolyzed. Finally, the sugar concentrations (glucose, xylose and arabinose) from filtrate and from hydrolysate were determined by HPLC. The recovery of xylose from hemicellulose was about 50% using the sulfuric acid pretreatment and less than 2% using the sodium hydroxide pretreatment. Increasing concentrations of sulfuric acid

  10. Comportamento fisiológico de sementes osmocondicionadas de Platymiscium pubescens Micheli (tamboril-da-mata

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    Borges Eduardo Euclydes de Lima e

    2002-01-01

    Full Text Available O objetivo deste trabalho foi investigar alterações fisiológicas e bioquímicas em sementes osmocondicionadas de tamboril-da-mata (Platymiscium pubescens Micheli. Foram analisados o crescimento do eixo embrionário, a germinação, as alterações na parede celular, a mobilização de carboidratos e proteínas e a atividade de a-galactosidase. Observou-se que o teor de umidade das sementes da testemunha aumentou continuamente até 96 horas de embebição, enquanto as mantidas nas soluções de PEG estabilizaram-se a partir de 48 horas. A germinação ocorreu somente nas sementes mantidas em água, alcançando 30% em 120 horas. As sementes mantidas em solução-0,4 MPa de PEG por 120 horas tiveram 66% de germinação quando transferidas para água, sendo a maior em relação aos demais potenciais. A massa fresca e o comprimento do embrião aumentaram significativamente durante o período de 120 horas em solução de PEG (-0,4 MPa/120 horas, porém a massa seca teve incremento não-significativo. Os teores de arabinose e xilose em membranas lavadas com água decresceram significativamente durante o osmocondicionamento. A galactose não foi detectada na membrana em 120 horas. A arabinose mostrou ser a principal constituinte da membrana. A atividade de a-galactosidase mostrou diferença significativa durante o período de 120 horas. Os teores de ramnose, arabinose e xilose alteraram-se significativamente na fração péctica, enquanto a ramnose foi a única na fração hemicelulósica. A glicose foi detectada somente nessa última fração. Os teores de glicose no embrião e cotilédones alteraram-se significativamente durante o osmocondicionamento. Os teores de estaquiose e de rafinose não tiveram alterações significativas nos cotilédones, enquanto o de sacarose reduziu-se significativamente, mantendo-se mais alto do que os dos outros dois oligossacarídeos. O teor de proteína decresceu significativamente nas 120 horas de

  11. 若干双子叶与单子叶植物细胞壁果胶结构单糖组成特征研究%Comparison of pectin structural monosaccharides in cell wall of dicotyledon and monocotyledon

    Institute of Scientific and Technical Information of China (English)

    程小乔; 李科; 陈雪梅; 蒋湘宁; 盖颖

    2012-01-01

    To study the angiosperm pectin monosaccharide components and content in primary cell wall as well as its relation with plants’ systematics between dicotyledon and monocotyledon,gas chromatograph-mass spectrometry ( GC / MS) was performed to detect the pectin monosaccharide components and content in 22 angiosperms and the data were analyzed by principal component analysis ( PCA ) ,Student’s test and Shannon-Weiner index analysis. Seven monosaccharides were found in angiosperm pectin including xylose,rhamnose,fucose,arabinose,galactose,glucose and mannose. The pectin was particularly rich in rhamnose,arabinose and galactose,but with little fucose and mannose. Five pectin monosaccharides were screened from 22 plants by PCA,and they were xylose,arabinose,rhamnose,galactose,and glucose respectively. Two-dimensional chart and Student’s test showed that the significantly different content of xylose or galactose in pectin could provide a reference for distinguishing class dicotyledon from class monocotyledon ( P 〈 0. 01 ) . The Shannon-Wiener index showed the more diversities of monosaccharide in dicotyledon than monocotyledon ( P 〈 0. 01) . Taken together,the different content of pectin monosaccharide could provide a reference for the angiosperms’ systematics between dicotyledon and monocotyledon.%为了系统研究被子植物初生壁果胶结构单糖的组成成分及其与被子植物两纲分类的关系,结合单糖单一环式的衍生化方法,采用GC/MS测定22种被子植物初生壁果胶中单糖组分及含量,并对测得的结果进行主成分、t检验和香农一威纳指数分析。结果表明:被子植物细胞壁果胶由木糖、鼠李糖、岩藻糖、阿拉伯糖、半乳糖、葡萄糖、甘露糖7种单糖组成,其中鼠李糖、阿拉伯糖和半乳糖含量较高;岩藻糖和甘露糖含量极少。主成分分析筛选出决定22种被子植物间糖含量差异的5种果胶单糖分别为:木糖、阿拉伯糖

  12. 鹿蹄草多糖LTC-Ⅱ分离纯化及结构性质研究%Studies on separation, purification and structure characteristics of a polysaccharide LTC-Ⅱ from Pyrola corbieri

    Institute of Scientific and Technical Information of China (English)

    莫正昌; 吴兰芳; 杨娟; 王道平

    2011-01-01

    Objective: To characterize the structure of polysaccharide LTC-Ⅱ obtained from Pyrola corbieri.Method: The polysaccharide was extracted from P.corbieri by hot water and ethanol precipitation.Crude polysaccharide was purified by DEAE-Cellulose chromatography and Sephacryl S-300 HR column chromatography.The purity and molecular weight of polysaccharide was determined by gel permeation chromatography.UV, IR, optical rotation, complete acid hydrolysis, periodate oxydation, Smith degradation, partial acid hydrolysis and methylation analysis were applied to determine the structural features.Result: A homogeneous fraction LTC-Ⅱ was obtained and its relative molecular mass was 22 000 Da.It consisted of arabinose, mannose, glucose, galactose in the molar ratio of 35.2∶1.0:13.4∶4.2.LTC-Ⅱ had a backbone consisting glucose, mannose, galactose and mainly contained (1→6)-linkaged glucose.The side chain possessed arabinose, glucose, galactose and mainly contained (1→5)-linkaged arabinose.The terminal sugar were mainly glucose and galactose.Conclusion: Studies on the preliminary characterization of polysaccharide LTC-Ⅱ from P.corbieri for the first time.%目的:研究鹿蹄草多糖LTC-Ⅱ的结构性质.方法:热水提取,乙醇沉淀制备鹿蹄草粗多糖,粗多糖经DEAE-纤维素和Sephacryl S-300 HR柱色谱分离纯化.采用高效凝胶渗透色谱法鉴定纯度并测定相对分子质量;紫外、红外、旋光、完全酸水解、高碘酸氧化及Smith降解、部分酸水解、甲基化分析对纯多糖组分进行结构性质研究.结果:得到一多糖纯组分LTC-Ⅱ,其相对分子质量为22 000 Da.单糖组成为阿拉伯糖、甘露糖、葡萄糖、半乳糖,其摩尔比为35.2:1.0:13.4:4.2,LTC-Ⅱ主链由甘露糖、葡萄糖和半乳糖组成,以(1→6)连接的葡萄糖为主,分支侧链由阿拉伯糖、葡萄糖和半乳糖组成,以(1→5)连接的阿拉伯糖为主,葡萄糖和半乳糖位于分子的末端.结论:首次对鹿蹄

  13. Radiation Induced DNA Double Strand Break Studies of a Metal Sensitive Novel Bacterial Isolate from East Calcutta Wetland

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    Sanhita Chowdhury

    2009-01-01

    Full Text Available Problem statement: This study was an attempt to isolate anaerobic microbes with potential for DNA double strand break repair using methanogen specific medium (DSMZ 120 from East Calcutta Wetland in India. It also intended to verify the specificity of the medium for isolation of the desired family of microbe. Approach: Culture based technique was used to obtain the pure isolate that was further characterized in details. For double strand break repair studies, isolate was irradiated with different doses of 60Co gamma rays and its subsequent repair was observed using pulse field gel electrophoresis and asymmetric field inversion gel electrophoresis. Inhibitor was used to predict the mechanism of repair. Results: In this study we isolated and characterized a metal sensitive anaerobic microbial strain obtained using methanogen specific medium (DSMZ 120 from East Calcutta Wetland in India. The strain was one of the members of the group of uncultivated bacterium as evident from phylogenetic analysis, thus indicating the successful cultivation of an as yet uncultivable novel microbe (GenBank Acc. No. FJ 930097 and also the non-specific growth of microbes in prescribed medium. It was a Gram positive Bacilli, member of Fermicutes with optimum growth at 25°C and pH-7. The growth curve analysis showed a lag phase up to 24 h, log phase from 24-48 h, an early stationary phase from 96 h onwards. The strain could repair the DNA double strand break caused by irradiation with 60Co γ rays. The dose profile study revealed maximum repair at 60 Grays and thereafter a drop in repair ability with increase in irradiation dose. The time required for repair showed an essential incubation period of 4 h. The DNA polymerase inhibitor, Arabinose CTP inhibited the repair indicating the involvement of polymerase in the repair process and thus pointing towards homologous recombination as the underlying mechanism. Conclusion: In this study we were able to cultivate an as yet

  14. Multisubstrate isotope labeling and metagenomic analysis of active soil bacterial communities.

    Science.gov (United States)

    Verastegui, Y; Cheng, J; Engel, K; Kolczynski, D; Mortimer, S; Lavigne, J; Montalibet, J; Romantsov, T; Hall, M; McConkey, B J; Rose, D R; Tomashek, J J; Scott, B R; Charles, T C; Neufeld, J D

    2014-07-15

    Soil microbial diversity represents the largest global reservoir of novel microorganisms and enzymes. In this study, we coupled functional metagenomics and DNA stable-isotope probing (DNA-SIP) using multiple plant-derived carbon substrates and diverse soils to characterize active soil bacterial communities and their glycoside hydrolase genes, which have value for industrial applications. We incubated samples from three disparate Canadian soils (tundra, temperate rainforest, and agricultural) with five native carbon ((12)C) or stable-isotope-labeled ((13)C) carbohydrates (glucose, cellobiose, xylose, arabinose, and cellulose). Indicator species analysis revealed high specificity and fidelity for many uncultured and unclassified bacterial taxa in the heavy DNA for all soils and substrates. Among characterized taxa, Actinomycetales (Salinibacterium), Rhizobiales (Devosia), Rhodospirillales (Telmatospirillum), and Caulobacterales (Phenylobacterium and Asticcacaulis) were bacterial indicator species for the heavy substrates and soils tested. Both Actinomycetales and Caulobacterales (Phenylobacterium) were associated with metabolism of cellulose, and Alphaproteobacteria were associated with the metabolism of arabinose; members of the order Rhizobiales were strongly associated with the metabolism of xylose. Annotated metagenomic data suggested diverse glycoside hydrolase gene representation within the pooled heavy DNA. By screening 2,876 cloned fragments derived from the (13)C-labeled DNA isolated from soils incubated with cellulose, we demonstrate the power of combining DNA-SIP, multiple-displacement amplification (MDA), and functional metagenomics by efficiently isolating multiple clones with activity on carboxymethyl cellulose and fluorogenic proxy substrates for carbohydrate-active enzymes. Importance: The ability to identify genes based on function, instead of sequence homology, allows the discovery of genes that would not be identified through sequence alone. This

  15. Effects of Combinatorial Expression of selA, selB and selC Genes on the Efficiency of Selenocysteine Incorporation in Escherichia coli

    Institute of Scientific and Technical Information of China (English)

    XU Ya-wei; YAN Gang-lin; LUO Gui-min; JIANG Zhi-hua; MU Ying; ZHANG Lei; ZHAO Si-qi; LIU Shu-jun; WANG Cheng; ZHAO Yang; L(U) Shao-wu

    2013-01-01

    In Escherichia coli,four gene products(selA,selB,selC and selD) and a selenocysteine(Sec) insertion sequence(SECIS) are required for the correct translation of UGA codons encoding Sec.Previous studies have shown that the stoichiometry of selenoproteine mRNA and elongation factor SelB affect the efficiency of Sec incorporation.Herein lies a detailed analysis of the effects of co-expressing selA,selB and selC genes under inducible promoters on the incorporation efficiency of Sec.Over-expression of either selA or selB reduced the efficiency of Sec incorporation by 61.1% or 11.6%,respectively,compared to the over-expression of the reporter vector alone did.Concomitant over-expression of selC with selA or selB completely reversed the reduce of the efficiency of Sec but still reduced the efficiency of the incorporation relative to that observed for expression of selC alone.Over-expression of selC gene alone under L-arabinose induction reduced the efficiency of the incorporation relative to that observed for co-expressing selC with selA and selB under the control of its endogenous promoter in the absence of L-arabinose.Co-expression of selA,selB and selC with selA or selB under the control of inducible promoters increased the efficiency of Sec incorporation by 69.7%.Moreover,inducing selenoprotein-related gene expression during the late exponential phase increased the efficiency of Sec incorporation by a factor of 5.4 relative to that observed for the reporter vector alone.These results suggest that the co-expression of selA,selB and selC in Escherichia coli under the control of inducible promoters is a viable and promising strategy for increasing the yields of selenoproteins.

  16. Universal platform for quantitative analysis of DNA transposition

    Directory of Open Access Journals (Sweden)

    Pajunen Maria I

    2010-11-01

    Full Text Available Abstract Background Completed genome projects have revealed an astonishing diversity of transposable genetic elements, implying the existence of novel element families yet to be discovered from diverse life forms. Concurrently, several better understood transposon systems have been exploited as efficient tools in molecular biology and genomics applications. Characterization of new mobile elements and improvement of the existing transposition technology platforms warrant easy-to-use assays for the quantitative analysis of DNA transposition. Results Here we developed a universal in vivo platform for the analysis of transposition frequency with class II mobile elements, i.e., DNA transposons. For each particular transposon system, cloning of the transposon ends and the cognate transposase gene, in three consecutive steps, generates a multifunctional plasmid, which drives inducible expression of the transposase gene and includes a mobilisable lacZ-containing reporter transposon. The assay scores transposition events as blue microcolonies, papillae, growing within otherwise whitish Escherichia coli colonies on indicator plates. We developed the assay using phage Mu transposition as a test model and validated the platform using various MuA transposase mutants. For further validation and to illustrate universality, we introduced IS903 transposition system components into the assay. The developed assay is adjustable to a desired level of initial transposition via the control of a plasmid-borne E. coli arabinose promoter. In practice, the transposition frequency is modulated by varying the concentration of arabinose or glucose in the growth medium. We show that variable levels of transpositional activity can be analysed, thus enabling straightforward screens for hyper- or hypoactive transposase mutants, regardless of the original wild-type activity level. Conclusions The established universal papillation assay platform should be widely applicable to a

  17. The effect of free and protected oils on the digestion of dietary carbohydrates between the mouth and duodenum of sheep.

    Science.gov (United States)

    McAllan, A B; Knight, R; Sutton, J D

    1983-05-01

    Sheep fitted with rumen and re-entrant duodenal cannulas were given diets of approximately 200 g hay and 400 g concentrate mixture alone, or supplemented daily with 40 g linseed or coconut oils free or protected with formaldehyde-casein in a 5 x 5 Latin-square arrangement. Chromic oxide paper was given as a marker at feeding time and passage to the duodenum of neutral-detergent fibre (NDF) and different sugars were estimated from the values for constituent:marker at the duodenum. Contributions of microbial carbohydrates to these flows were estimated from amounts of RNA present. The carbohydrate composition of mixed rumen bacteria from sheep rumen digesta were similar regardless of diet. Of the sugars entering the duodenum all the rhamnose and ribose and 0.51, 0.24 and 0.35 of the mannose, galactose and starch-glucose respectively, were contributed by the microbes. Virtually all the arabinose, xylose and cellulose-glucose were contributed by the diet. For sheep receiving the basal ration, coefficients of digestibility between mouth and duodenum, corrected where necessary for microbial contribution, were 0.95, 0.66, 0.67, 0.62, 0.45 and 0.51 for starch-glucose, mannose, arabinose, galactose, xylose and cellulose-glucose respectively. Corresponding values when free-oil-supplemented diets were given were 0.95, 0.55, 0.38, 0.55, 0.01 and -0.02 respectively. Values for diets supplemented with linseed oil or coconut oil did not differ significantly. Addition of protected oils to the basal feed also resulted in depressed digestibilities of dietary structural sugars but to a far lesser extent than those observed with the free oils. Apparent digestibility of NDF was altered in the same direction as those of the main structural sugars, averaging 0.50, 0.17 and 0.29 in animals receiving the basal, free-oil-supplemented or protected-oil-supplemented diets respectively. The reasons for the difference between NDF and discrete carbohydrate analytical totals are discussed.

  18. Factors influencing the digestion of dietary carbohydrates between the mouth and abomasum of steers.

    Science.gov (United States)

    McAllan, A B; Smith, R H

    1983-09-01

    Six protozoa-free steers with simple rumen and abomasal cannulas were given basal diets consisting of a concentrate mixture of flaked maize and tapioca with either barley straw (BS) or alkali-treated barley straw (BSA). Other diets used were supplemented with urea (BSU and BSAU respectively) or contained fish meal in place of tapioca BSF and BSAF respectively). The diets were given in a 6 X 6 Latin square design. Diets were isoenergetic and provided sufficient metabolizable energy (ME) to support a growth rate of approximately 0.5 kg/d. Basal diets, urea- and fish-meal-supplemented diets had estimated rumen-degradable nitrogen (RDN):ME values (g/MJ) of 0.5, 1.2 and 0.8 respectively. 103Ruthenium and polyethylene glycol were given as flow markers, and flows (g/24 h) at the abomasum of organic matter (OM) and carbohydrate components were calculated. True digestibility coefficients of OM between mouth and abomasum were significantly greater for diets containing alkali-treated straw (approximately 0.63) than for those containing untreated straw (approximately 0.55) but were not significantly affected by N supplementation. Digestibility coefficients of the neutral-sugar components of dietary polysaccharides between mouth and abomasum were 0.28, 0.34, 0.31, 0.23, 0.31 and 0.87 for mannose, galactose arabinose, xylose, cellulose-glucose and starch-glucose respectively for diet BS. Corresponding values were 0.37, 0.42, 0.56, 0.51, 0.40 and 0.88 for diet BSA. All but the mannose and starch-glucose values were significantly greater for the latter diet. N supplementation also led to increases in digestibility of all neutral sugars except mannose and starch-glucose. Fish meal produced a markedly greater effect than urea but only significantly so for cellulose-glucose. Thus, the highest digestibilities were seen for diet BSAF and were 0.68, 0.67, 0.74 and 0.64 for galactose, arabinose, xylose and cellulose-glucose respectively. Of all these sugars xylose consistently showed the

  19. Decoding glycome of Astragalus membranaceus based on pressurized liquid extraction, microwave-assisted hydrolysis and chromatographic analysis.

    Science.gov (United States)

    Lv, G P; Hu, D J; Cheong, K L; Li, Z Y; Qing, X M; Zhao, J; Li, S P

    2015-08-28

    Carbohydrates in herbs are a relatively untapped source of new drugs and health beneficial ingredients. Their analysis has been developed as a novel aspect in quality control and herbal glycomics. In this study, glycome of Astragalus membranaceus was decoded based on optimized pressurized liquid extraction (PLE), microwave-assisted acidic hydrolysis (MAAH) and comprehensive chromatographic approaches. Twelve saccharides including sucrose, galacturonic acid, mannitol, fructose, rhamnose, ribose, arabinose, fucose, xylose, mannose, glucose and galactose were quantitatively analyzed by GC-MS and HPLC-CAD (charged aerosol detectors). Different columns, including Prevail Carbohydrate ES, XBridge Amide and CARBOSep CHO-820 CA for HPLC-CAD analysis, were compared for evaluation of oligosaccharides. The polysaccharides in water extract of Astragalus membranaceus were characterized by high performance size exclusive chromatography (HPSEC) combined with multiple angle light scattering detection (MALSD) and refractive index detection (RID). The results showed that A. membranaceus contained more than 108.5mgg(-1) free sucrose and small amounts of glucose 9.6-26.0mgg(-1) and fructose 8.7-22.9mgg(-1). While its polymeric carbohydrates were composed of glucose 71.0-162.3mgg(-1), galacturonic acid 52.0-113.4mgg(-1), arabinose 22.8-54.4mgg(-1) and small amounts of galactose, rhamnose, xylose and mannose. CARBOSep CHO-820 CA showed its potential in simultaneously analyzing oligosaccharides and uronic acid, especially only the environment-friendly water mobile phase was used. HPSEC-MALSD-RID showed that there were three different molecular weight distributions of polysaccharides in A. membranaceus and the average molecular weight were 21901.1, 2038.5, and 353.4kDa. Hierarchical clustering analysis and principal component analysis demonstrated that A. membranaceus from different regions showed variations both in free and polymeric carbohydrates, which indicated that carbohydrates

  20. Biopolímero produzido a partir da cana-de-áçucar para cicatrização cutânea Sugar cane biopolymer in cutaneous healing

    Directory of Open Access Journals (Sweden)

    Maria Cristina de Oliveira Cardoso Coelho

    2002-01-01

    Full Text Available Um polissacarídeo extracelular foi produzido por via microbiológica, através da bactéria ZSP isolada no Laboratório de Microbiologia Industrial da Estação Experimental de Cana-de-Açúcar do Carpina/UFRPE, apresentando excepcional capacidade de processo. Os principais monossacarídeos presentes na fração solúvel foram glicose (87,6%, xilose (8,6%, manose (0,8%, ribose (1,7%, galactose (0,1%, arabinose (0,4% e o ácido glucurônico (0,8%. Devido ao alto índice de traumatismos que acomete os animais domésticos e a busca por alternativas simples, econômicas e capazes de proporcionar condições ideais para cicatrização, foram realizados os testes com o biopolímero produzido a partir da cana-de-açúcar em animais portadores de feridas cutâneas, a fim de avaliar a reepitelização. Observou-se o aumento do tecido de granulação, controle da infecção e diminuição do tempo de cicatrização, permitindo concluir que o biopolímero contribui para o processo cicatricial, podendo ser utilizado em feridas cutâneas.An extracelular polysaccharide was produced through microbiology, using the ZSP bacteria isolated in the Industrial Microbiological Laboratory of the Sugar cane Experimental Station at Carpina/UFRPE, Pernambuco, Brazil, presenting exceptional process capacity. The principal monosaccharides present in the ¹soluble fraction were glucose (87.6%, xylose (8.6%, mannose (0.8%, ribose (1.7%, galactose (0.1%, arabinose (0.4% and the glucuronic acid (0.8%. Due to the high rate of injuries that occur with domestic animals and the search for simple, economical alternatives that would be capable of giving ideal conditions for the healing process, extensive testing was done with the biopolymer produced by sugar cane in animals that had cutaneous wounds, so as to evaluate the reepitelization process. It was observed from the testing results that there was better skin granulation, better infection control, and less healing time, which

  1. Effect of superfine comminution on reducing sugar components in corn stalk enzymatic hydrolysate%超微粉碎预处理对玉米秸杆酶解液中还原糖组分的影响

    Institute of Scientific and Technical Information of China (English)

    赵晓燕; 朱海涛; 张桂香; 张立金; 何磊

    2015-01-01

    The compositions of five different monosaccharides in corn stalk enzymatic hydrolysate were an-alyzed by HPLC.They were arabinose,mannose,galactose,glucose and fructose,in which glucose and fructose were the main compositions.The results showed that the reducing sugar composition contents in corn stalk powder with a particle >1 200 mesh was higher than that with a particle size 100 ~200 mesh. The content of arabinose,galactose,glucose,mannose and fructose in enzymatic hydrolysate with particle size of >1 200 mesh increased 48.38%、64.29%、37.63%、70.07% and 22.34%,respectively.In addition,three new unknown response peaks occurred in the chromatograms,which might be fucose,su-crose and cellobiose.%HPLC 分析了玉米秸杆微粉酶解液中5种单糖组成,主要包括阿拉伯糖、甘露糖、半乳糖、葡萄糖、果糖,其中以葡糖糖与果糖为主。结果表明:粒径大于1200目的玉米秸杆粉酶解液还原糖单糖组分与100~200目的相比,其含量明显高,阿拉伯糖、半乳糖、葡萄糖、甘露糖和果糖分别提高了48.38%、64.29%、37.63%、70.07%和22.34%。此外,在超微细秸杆粉的酶解液 HPLC 色谱图上出现三个新的未知响应峰,推测可能为岩藻糖、庶糖与纤维二糖。

  2. Oxygen isotope ratios (18O/16O) of hemicellulose-derived sugar biomarkers in plants, soils and sediments as paleoclimate proxy II: Insight from a climate transect study

    Science.gov (United States)

    Tuthorn, Mario; Zech, Michael; Ruppenthal, Marc; Oelmann, Yvonne; Kahmen, Ansgar; Valle, Héctor Francisco del; Wilcke, Wolfgang; Glaser, Bruno

    2014-02-01

    The oxygen isotopic composition of precipitation (δ18Oprec) is well known to be a valuable (paleo-)climate proxy. Paleosols and sediments and hemicelluloses therein have the potential to serve as archives recording the isotopic composition of paleoprecipitation. In a companion paper (Zech et al., 2014) we investigated δ18Ohemicellulose values of plants grown under different climatic conditions in a climate chamber experiment. Here we present results of compound-specific δ18O analyses of arabinose, fucose and xylose extracted from modern topsoils (n = 56) along a large humid-arid climate transect in Argentina in order to answer the question whether hemicellulose biomarkers in soils reflect δ18Oprec. The results from the field replications indicate that the homogeneity of topsoils with regard to δ18Ohemicellulose is very high for most of the 20 sampling sites. Standard deviations for the field replications are 1.5‰, 2.2‰ and 1.7‰, for arabinose, fucose and xylose, respectively. Furthermore, all three hemicellulose biomarkers reveal systematic and similar trends along the climate gradient. However, the δ18Ohemicellulose values (mean of the three sugars) do not correlate positively with δ18Oprec (r = -0.54, p fucose and xylose do not simply reflect δ18Oprec but rather δ18Oleaf water. The correlation between measured δ18Ohemicellulose and modeled δ18Oleaf water is highly significant (r = 0.81, p < 0.001, n = 20). This finding can be attributed to the evaporative 18O enrichment of leaf water during transpiration. Model sensitivity tests using a Péclet-modified Craig-Gordon (PMCG) model corroborate that relative air humidity is a very rigorous climate parameter influencing δ18Oleaf water, whereas temperature is of minor importance. While oxygen exchange and degradation effects on δ18O values of hemicelluloses sugar biomarkers seem to be negligible (Zech et al., 2012), further effects that need to be considered when interpreting δ18Ohemicellulose

  3. Secretory expression of arginine deiminase in E.coli%精氨酸脱亚胺酶在大肠杆菌中的分泌型表达

    Institute of Scientific and Technical Information of China (English)

    李娜; 倪晔; 孙志浩

    2012-01-01

    The arginine deiminase (ADI) encoding gene arcA of P. Plecoglossicida CGMCC2039 was cloned into secreted expression vector pBAD/glll B under araBAD promoter (pBAD), and the resulted recombinant plasmid pBAD-ADI was transformed into E. Coli TOP10F'. The effect of induction conditions on ADI expression was investigated, including L-arabinose concentration, induction temperature, and induction time. The optimum induction conditions were determined to be 0. 002% L-arabinose, 25 t and 5 h, and the ADI activity of whole cells was 68 mU/mL broth. The recombinant ADI in periplasmic space was released by osmotic shock, the ADI activity in periplasmic and cellular fraction were 53 mU/mL broth and 34 mU/mL broth, respectively. SDS-PAGE analysis showed that the molecular mass of recombinant ADI was about 46 kD.%将变形假单胞菌的精氨酸脱亚胺酶(ADI)编码基因arcA克隆至具有阿拉伯糖启动子的分泌型表达载体pBAD/gⅢ B中,经鉴定得到重组质粒pBAD-ADI.将重组质粒转化大肠杆菌TOP10F’后进行诱导表达,分别考察了不同诱导物L-arabinose浓度、诱导温度、诱导时间对重组蛋白表达的影响,最适诱导条件为L-arabinose浓度0.002% (w/v),25℃下诱导5h,全细胞的酶活为68 mU/mL(指单位发酵液体积,下同).采用Osmotic Shock法使ADI从胞周质释放出来,经检测分泌到胞周质的重组蛋白活性为53 mU/mL,细胞内的酶活为34 mU/mL.SDS-PAGE分析显示,重组蛋白大小约为46 kD.

  4. 菠萝皮果胶的分离纯化及组成分析%Extraction, Purification and Compositional Analysis of Pineapple Rind Pectin

    Institute of Scientific and Technical Information of China (English)

    徐雪荣; 冯静; 梁瑞红; 刘成梅; 周晶

    2012-01-01

    以热带水果菠萝皮为原料,采用漂烫灭酶、酸法提取和醇沉工艺提取果胶,对提取果胶的分离纯化和组成进行研究.结果表明:菠萝皮果胶经离子交换层析后分离纯化出1个中性组分,命名为PRP-N,2个酸性组分,命名为PRP-1、PRP-2.比对PRP-1、PRP-2的组成和结构发现,PRP-1的半乳糖醛酸含量较低,中性糖含量较高,单糖成分主要为鼠李糖、半乳糖和阿拉伯糖,以鼠李糖半乳糖醛酸Ⅰ型(RG-Ⅰ)结构为主,侧链主要成分为阿拉伯糖和半乳糖,通过4-O-Rha连接到主链上;PRP-2的半乳糖醛酸含量高,中性糖含量低,以半乳糖醛酸型(HG)和鼠李糖半乳糖醛酸Ⅱ型(RG-Ⅱ)结构为主,含有少量RG-Ⅰ型果胶分子结构.PRP-1比PRP-2的流体力学体积小,且聚合度分布更集中.%A pectin was prepared by blanching, acid extraction, and alcohol precipitation from tropical pineapple rind. Its purification and composition were also analysed. The results showed this pectin could be completely fractionated into one neutral fraction (PRP-N) and two acidic fractions (PRP-1 and PRP-2) by ion-exchange chromatography. PRP-1 was mainly rhamnogalacturonan type I, which contained more neutral sugars than galacturonic acids. The neutrual sugars were comprised of rhamnose, galactose and arabinose, where galactose and arabinose connected to rhamnose through 4-O-Rha. For PRP-2, it contained more galacturonic acids than neutral sugars. It's structure contained homogalacturonan as well as rhamnogalacturonan type E with a very low amounts of rhamnogalacturonan type I. In addition, PRP-1 showed a smaller hydrodynamic volume and narrower distribution than PRP-2.

  5. Boron influence on concentration of polyols and other sugars in Eucalyptus Influência do boro na síntese de polióis e outros açúcares em Eucalyptus

    Directory of Open Access Journals (Sweden)

    Susi Meire Maximino Leite

    2008-10-01

    Full Text Available Although the functions of the element Boron (B in plants have not been sufficiently clarified, several hypotheses have been raised. Some of the functions attributed to this element are synthesis and transport of carbohydrates. To evaluate the effect of B on the synthesis of some polyols and sugars in Eucalyptus grandis and hybrids "urograndis", these species were submitted to situations of supply and restriction of B. The experiment was carried out in a greenhouse, arranged in a randomized block design in a 2 x 2 factorial scheme, with 5 replicates of each genotype. The B levels were provided in the form of nutrient solution. No significant difference was observed in the content of mannitol, sorbitol, myo-inositol and scyllo-inositol and sugars α-glucose and β-glucose between E. grandis and hybrids. Arabinose was the only one to present a higher content in E. grandis on restriction of B. The effect of the presence of B was very expressive, but regarding B supply, the plants showed significant increase in the synthesis of the compounds evaluated.Embora a função do elemento Boro (B nas plantas ainda não tenha sido bem esclarecida, várias hipóteses vêm sido levantadas. Uma das funções atribuídas a esse elemento é a síntese de carboidratos. Com o objetivo de avaliar o efeito do B sobre a síntese de alguns polióis e açúcares em Eucalyptus grandis e híbridos "urograndis", estes foram submetidos à situação de suprimento e restrição de B. O experimento foi conduzido em casa de vegetação de acordo com o delineamento de blocos casualizados com cinco repetições, e os elementos nutricionais, assim como o B, foram fornecidos na forma de solução nutritiva. Não se observou diferença significativa nos teores de manitol, sorbitol, myo-inositol e scyllo-inositol e dos açúcares α-glicose e β-glicose entre E. grandis e híbridos. Arabinose foi o único a apresentar maior teor em E. grandis em restrição de B. O efeito da presen

  6. Tomato fruit cell wall : I. Use of purified tomato polygalacturonase and pectinmethylesterase to identify developmental changes in pectins.

    Science.gov (United States)

    Koch, J L; Nevins, D J

    1989-11-01

    , the release of uronides by polygalacturonase from all pectinesterase treated cell walls was equivalent to polygalacturonase treatment of walls at the ripe stage. Uronide polymers released by polygalacturonase contain galacturonic acid, rhamnose, galactose, arabinose, xylose, and glucose. As a function of development, an increase in the release of galacturonic acid and rhamnose was observed (40 and 6% of these polymers at the mature green stage to 54 and 15% at the red ripe stage, respectively). The amount of galactose and arabinose released by exogenous polygalacturonase decreased during development (41 and 11% from walls of mature green fruit to 11 and 6% at the red ripe stage, respectively). Minor amounts of glucose and xylose released from the wall by exogenous polygalacturonase (4-7%) remained constant throughout fruit development.

  7. Competency of Anopheles stephensi mysorensis strain for Plasmodium vivax and the role of inhibitory carbohydrates to block its sporogonic cycle

    Directory of Open Access Journals (Sweden)

    Whitten Miranda MA

    2008-07-01

    Full Text Available Abstract Background Despite the abundance of studies conducted on the role of mosquitoes in malaria transmission, the biology and interaction of Plasmodium with its insect host still holds many mysteries. This paper provides the first study to follow the sporogonic cycle of Plasmodium vivax in a wild insecticide-resistant mysorensis strain of Anopheles stephensi, a major vector of vivax malaria in south-eastern Iran. The study subsequently demonstrates that host-parasite sugar binding interactions are critical to the development of this parasite in the salivary glands of its mosquito host. The identity of the receptors or sugars involved was revealed by a receptor "pre-saturation" strategy in which sugars fed to the mosquitoes inhibited normal host-parasite interactions. Methods Anopheles stephensi mysorensis mosquitoes were artificially infected with P. vivax by feeding on the blood of gametocytaemic volunteers reporting to local malaria clinics in the Sistan-Baluchistan province of south-eastern Iran. In order to determine the inhibitory effect of carbohydrates on sporogonic development, vector mosquitoes were allowed to ingest blood meals containing both gametocytes and added carbohydrates. The carbohydrates tested were GlcNAc, GalNAc, arabinose, fucose, mannose, lactose, glucose and galactose. Sporogonic development was assessed by survival of the parasite at both the oocyst and sporozoite stages. Results Oocyst development was observed among nearly 6% of the fed control mosquitoes but the overall number of mosquitoes exhibiting sporozoite invasion of the salivary glands was 47.5% lower than the number supporting oocysts in their midgut. Of the tested carbohydrates, only arabinose and fucose slightly perturbed the development of P. vivax oocysts at the basal side of the mosquito midgut, and the remaining sugars caused no reductions in oocyst development. Strikingly however, sporozoites were completely absent from the salivary glands of

  8. Bacterial utilization of L-sugars and D-amino acids

    Science.gov (United States)

    Pikuta, Elena V.; Hoover, Richard B.; Klyce, Brig; Davies, Paul C. W.; Davies, Pauline

    2006-08-01

    The fact that organotrophic organisms on Earth use L-amino acids and D-sugars as an energy source is recognized as one of the universal features of life. The chirality of organic molecules with asymmetric location of group-radicals was described a relatively long time ago. Louis Pasteur observed that abiotic (chemical) processes produced mixtures with equal numbers (racemic) of the two forms but that living organisms possessed a molecular asymmetry that included only one of the enantiomers (homochirality). He speculated that the origin of the asymmetry of chiral biomolecules might hold the key to the nature of life. All of the amino acids in proteins (except for Glycine which is symmetrical) exhibit the same absolute steric configuration as L-glyceraldehyde. D-amino acids are never found in proteins, although they do exist in nature and are often found in polypeptide antibiotics. Constitutional sugars of cells, opposite to the amino acids, are the D-enantiomers, and the appearance of L-sugars in Nature is extremely rare. Notwithstanding this fact, the metabolism of some bacteria does have the capability to use amino acids and sugars with alternative chirality. This property may be caused by the function of specific enzymes belonging to the class of isomerases (racemases, epimerases, isomerases, tautomerases). In our laboratory, we have investigated several anaerobic bacterial strains, and have found that some of these bacteria are capable of using D-amino acids and L-sugars. Strain BK1 is capable of growth on D-arginine, but its growth characteristics on L-arginine are approximately twice as high. Another alkaliphilic strain SCA T (= ATCC BAA-1084 T = JCM 12857 T = DSM 17722 T = CIP 107910 T) was found to be capable of growth on L-ribose and L-arabinose. It is interesting that this strain was incapable of growth on D-arabinose, which suggests the involvement of some alternative mechanism of enzyme activity. In this paper, we describe the preliminary results of

  9. Xylitol production from xylose mother liquor: a novel strategy that combines the use of recombinant Bacillus subtilis and Candida maltosa

    Directory of Open Access Journals (Sweden)

    Jiang Mingguo

    2011-02-01

    Full Text Available Abstract Background Xylose mother liquor has high concentrations of xylose (35%-40% as well as other sugars such as L-arabinose (10%-15%, galactose (8%-10%, glucose (8%-10%, and other minor sugars. Due to the complexity of this mother liquor, further isolation of xylose by simple method is not possible. In China, more than 50,000 metric tons of xylose mother liquor was produced in 2009, and the management of sugars like xylose that present in the low-cost liquor is a problem. Results We designed a novel strategy in which Bacillus subtilis and Candida maltosa were combined and used to convert xylose in this mother liquor to xylitol, a product of higher value. First, the xylose mother liquor was detoxified with the yeast C. maltosa to remove furfural and 5-hydromethylfurfural (HMF, which are inhibitors of B. subtilis growth. The glucose present in the mother liquor was also depleted by this yeast, which was an added advantage because glucose causes carbon catabolite repression in B. subtilis. This detoxification treatment resulted in an inhibitor-free mother liquor, and the C. maltosa cells could be reused as biocatalysts at a later stage to reduce xylose to xylitol. In the second step, a recombinant B. subtilis strain with a disrupted xylose isomerase gene was constructed. The detoxified xylose mother liquor was used as the medium for recombinant B. subtilis cultivation, and this led to L-arabinose depletion and xylose enrichment of the medium. In the third step, the xylose was further reduced to xylitol by C. maltosa cells, and crystallized xylitol was obtained from this yeast transformation medium. C. maltosa transformation of the xylose-enriched medium resulted in xylitol with 4.25 g L-1·h-1 volumetric productivity and 0.85 g xylitol/g xylose specific productivity. Conclusion In this study, we developed a biological method for the purification of xylose from xylose mother liquor and subsequent preparation of xylitol by C. maltosa

  10. Broad-spectrum anti-biofilm peptide that targets a cellular stress response.

    Directory of Open Access Journals (Sweden)

    César de la Fuente-Núñez

    2014-05-01

    Full Text Available Bacteria form multicellular communities known as biofilms that cause two thirds of all infections and demonstrate a 10 to 1000 fold increase in adaptive resistance to conventional antibiotics. Currently, there are no approved drugs that specifically target bacterial biofilms. Here we identified a potent anti-biofilm peptide 1018 that worked by blocking (pppGpp, an important signal in biofilm development. At concentrations that did not affect planktonic growth, peptide treatment completely prevented biofilm formation and led to the eradication of mature biofilms in representative strains of both Gram-negative and Gram-positive bacterial pathogens including Pseudomonas aeruginosa, Escherichia coli, Acinetobacter baumannii, Klebsiella pneumoniae, methicillin resistant Staphylococcus aureus, Salmonella Typhimurium and Burkholderia cenocepacia. Low levels of the peptide led to biofilm dispersal, while higher doses triggered biofilm cell death. We hypothesized that the peptide acted to inhibit a common stress response in target species, and that the stringent response, mediating (pppGpp synthesis through the enzymes RelA and SpoT, was targeted. Consistent with this, increasing (pppGpp synthesis by addition of serine hydroxamate or over-expression of relA led to reduced susceptibility to the peptide. Furthermore, relA and spoT mutations blocking production of (pppGpp replicated the effects of the peptide, leading to a reduction of biofilm formation in the four tested target species. Also, eliminating (pppGpp expression after two days of biofilm growth by removal of arabinose from a strain expressing relA behind an arabinose-inducible promoter, reciprocated the effect of peptide added at the same time, leading to loss of biofilm. NMR and chromatography studies showed that the peptide acted on cells to cause degradation of (pppGpp within 30 minutes, and in vitro directly interacted with ppGpp. We thus propose that 1018 targets (pppGpp and marks it for

  11. Chemical compositions and bioactivities of crude polysaccharides from tea leaves beyond their useful date.

    Science.gov (United States)

    Xiao, Jianbo; Huo, Jianglei; Jiang, Huixian; Yang, Fan

    2011-12-01

    The chemical compositions and bioactivities of crude tea polysaccharides (TPS) from the out-of-date tea leaves (beyond their useful date), namely Xihu Longjing (XTPS), Anxi Tieguanyin (TTPS), Chawentianxia (CTPS) and Huizhoulvcha (HTPS), in market were investigated. These TPS showed similar neutral sugar content and different distribution of molecular weight (1-800 kD). These crude TPS were mainly composed of rhamnose, arabinose, galactose, glucose, xylose, mannose, and galacturonic acid. IR spectra confirmed that these crude TPS were composed of polysaccharide, protein and uronic acids. These TPS showed similar DPPH scavenging activity and exhibited lower DPPH scavenging activities than Vc within 25-200 μg/mL. However, these TPS with higher concentrations (200-400 μg/mL) showed similar DPPH scavenging activity with Vc. HTPS exhibited significant higher superoxide anion scavenging activity than others TPS and gallic acid. XTPS showed significant higher inhibitory effects on α-glucosidase and α-amylase with inhibitory percentages of 64.35% and 82.24% than others TPS. TTPS, XTPS, and HTPS exhibited similar inhibition ability on α-d-glucosidase and α-amylase. The overdue tea leaves can be a resource of tea polysaccharides as function food.

  12. Polysaccharides from Arctium lappa L.: Chemical structure and biological activity.

    Science.gov (United States)

    Carlotto, Juliane; de Souza, Lauro M; Baggio, Cristiane H; Werner, Maria Fernanda de P; Maria-Ferreira, Daniele; Sassaki, Guilherme L; Iacomini, Marcello; Cipriani, Thales R

    2016-10-01

    The plant Arctium lappa L. is popularly used to relieve symptoms of inflammatory disorders. A crude polysaccharide fraction (SAA) resulting of aqueous extraction of A. lappa leaves showed a dose dependent anti-edematogenic activity on carrageenan-induced paw edema, which persisted for up to 48h. Sequential fractionation by ultrafiltration at 50kDa and 30kDa cut-off membranes yielded three fractions, namely RF50, RF30, and EF30. All these maintained the anti-edematogenic effect, but RF30 showed a more potent action, inhibiting 57% of the paw edema at a dose of 4.9mg/kg. The polysaccharide RF30 contained galacturonic acid, galactose, arabinose, rhamnose, glucose, and mannose in a 7:4:2:1:2:1 ratio and had a Mw of 91,000g/mol. Methylation analysis and NMR spectroscopy indicated that RF30 is mainly constituted by a type I rhamnogalacturonan branched by side chains of types I and II arabinogalactans, and arabinan.

  13. Application and comparison of four selected procedures for the isolation of cell-wall material from the skin of grapes cv. Monastrell

    Energy Technology Data Exchange (ETDEWEB)

    Apolinar-Valiente, R., E-mail: tokay04@hotmail.com [Departamento de Tecnologia de Alimentos, Nutricion y Bromatologia, Facultad de Veterinaria, Universidad de Murcia, Campus de Espinardo, 30100 Murcia (Spain); Romero-Cascales, I., E-mail: miromero@um.es [Departamento de Tecnologia de Alimentos, Nutricion y Bromatologia, Facultad de Veterinaria, Universidad de Murcia, Campus de Espinardo, 30100 Murcia (Spain); Lopez-Roca, J.M., E-mail: jmlroca@um.es [Departamento de Tecnologia de Alimentos, Nutricion y Bromatologia, Facultad de Veterinaria, Universidad de Murcia, Campus de Espinardo, 30100 Murcia (Spain); Gomez-Plaza, E., E-mail: encarnag@um.es [Departamento de Tecnologia de Alimentos, Nutricion y Bromatologia, Facultad de Veterinaria, Universidad de Murcia, Campus de Espinardo, 30100 Murcia (Spain); Ros-Garcia, J.M., E-mail: jmros@um.es [Departamento de Tecnologia de Alimentos, Nutricion y Bromatologia, Facultad de Veterinaria, Universidad de Murcia, Campus de Espinardo, 30100 Murcia (Spain)

    2010-02-15

    In order to choose an appropriate cell-wall material (CWM) isolation procedure in grapes cv. Monastrell, four different standard procedures have been tested, and a comparison made of the amount of cell-wall material obtained, its composition and morphology. The CWM was isolated as the 70% ethanol insoluble residue (de Vries method), as the absolute ethanol insoluble residue filtered sequentially through nylon mesh (Nunan method), as the insoluble residue in sodium deoxycholate-phenol-acetic acid-water (Selvendran method) and as the N-[2-hydroxyethyl]-piperazine-N'-2-ethanesulfonic acid (HEPES) insoluble residue (Vidal method). All extractions were done in triplicate and the efficiency of the extractive procedure established. Carbohydrates, proteins, and phenolic compounds were analysed, as the main constituents of CWM. The morphology of the isolated CWM was visualized by scanning electron microscopy (SEM). The Selvendran method had the highest efficiency, while the Nunan method had the lower one. Regarding the carbohydrates composition, the four different CWM were rich in uronic acids and glucose, together with varying amounts of arabinose, xylose, mannose and galactose. The Selvendran method had the lower value of total carbohydrates and the CWM shows more plasmatic membrane impurities in SEM images. The chemical results of the Vidal and de Vries methods were quite similar, but the Vidal method was more time consuming than the de Vries method. According to the results, the de Vries method was chosen to produce a representative cell-wall material fraction from Monastrell grapes skin.

  14. Characterization of carbohydrates in rainwater from the southeastern North Carolina.

    Science.gov (United States)

    Mullaugh, Katherine M; Byrd, Jade N; Avery, G Brooks; Mead, Ralph N; Willey, Joan D; Kieber, Robert J

    2014-07-01

    Carbohydrates have been widely reported in atmospheric aerosols, but have not previously been quantified in rainwater. We have identified and quantified a series of 11 specific compounds including monosaccharides (glucose, fructose, arabinose, galactose and pinitol), disaccharides (sucrose and trehalose), sugar alcohols (arabitol, dulcitol and mannitol) and the anhydrosaccharide levoglucosan. Rainwater analyzed in this study includes 52 distinct precipitation events in Wilmington, NC between June 2011 and October 2012. Our analysis indicates carbohydrates typically contribute carbohydrates reached as high as 5.8 μM, with glucose and sucrose typically being the predominant species. The distribution of carbohydrates exhibited a distinct seasonal pattern, with higher concentrations of most carbohydrates, especially sucrose, in spring and summer, driven primarily by increased biogenic inputs during the growing season. Concentrations of carbohydrates were an order of magnitude higher in storms of terrestrial origin compared to marine events, further supporting a terrestrial biogenic origin of most species. Sequential sampling of Hurricane Irene showed significant quantities of carbohydrates present at the end of the storm when air mass back trajectories traversed over land. The highest level of levoglucosan, a compound associated with biomass burning, was detected in rain with an air mass back trajectory that traveled over a region affected by wildfires. When compared to aerosol concentrations reported by others, the sugar concentrations in rain demonstrate wet deposition is an important removal mechanism of this water-soluble and bioavailable fraction of atmospheric particulate organic matter.

  15. Nutritional Profile and Carbohydrate Characterization of Spray-Dried Lentil, Pea and Chickpea Ingredients

    Directory of Open Access Journals (Sweden)

    Susan M. Tosh

    2013-07-01

    Full Text Available Although many consumers know that pulses are nutritious, long preparation times are frequently a barrier to consumption of lentils, dried peas and chickpeas. Therefore, a product has been developed which can be used as an ingredient in a wide variety of dishes without presoaking or precooking. Dried green peas, chickpeas or lentils were soaked, cooked, homogenized and spray-dried. Proximate analyses were conducted on the pulse powders and compared to an instant mashed potato product. Because the health benefits of pulses may be due in part to their carbohydrate content, a detailed carbohydrate analysis was carried out on the pulse powders. Pulse powders were higher in protein and total dietary fibre and lower in starch than potato flakes. After processing, the pulse powders maintained appreciable amounts of resistant starch (4.4%–5.2%. Total dietary fibre was higher in chickpeas and peas (26.2% and 27.1% respectively than lentils (21.9%, whereas lentils had the highest protein content (22.7%. Pulse carbohydrates were rich in glucose, arabinose, galactose and uronic acids. Stachyose, a fermentable fibre, was the most abundant oligosaccharide, making up 1.5%–2.4% of the dried pulse powders. Spray-drying of cooked, homogenized pulses produces an easy to use ingredient with strong nutritional profile.

  16. Characterization of active polysaccharides of HemoHIM

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Kwang Sun; Shin, Myeong Suk; Bae, Beom Seon; Hwang, Yong Cheol [Kyonggi University, Suwon (Korea, Republic of); Ryu, Kwang Won [Chungju University, Chungju (Korea, Republic of)

    2007-07-15

    In this study, we aimed to elucidate the detailed structure and active moiety of polysaccharide, one of the active constituents of immune and hematopoietic modulating activities of HemoHIM. We first isolated the polysaccharide fractions from the hot water extracts of the each ingredient herbs (A. gigas, P. janonica, C. officinale) of HemoHIM and their mixture. These polysaccharides were composed of neutral (85.32-92.73%) and acidic (4.25-7.88%) saccharides, proteins (0.16-4.02%), and polyphenols (2.09-5.37%). The hydrolytic analysis of polysaccharide fractions showed that they commonly showed higher arabinose, galactose, and galacturonic acid contents. These result suggested that these polysaccharides may have higher contents of rhamnogalacturonan among pectic substances and the main active moiety is composed of polysaccharides. The anion exchange chromatography of HemoHIM and each ingredient herb extract using DEAE-Sepharose FF (Cl- form) column resulted in 1 non-adsorption and 8 adsorption fractions. The analysis of immune activity (lymphocyte proliferation) on these fractions showed that the fractions obtained by higher salt concentration carried the higher activity, but all fractions showed considerable immune activity

  17. Changes in physicochemical properties related to the texture of lotus rhizomes subjected to heat blanching and calcium immersion.

    Science.gov (United States)

    Zhao, Wenlin; Xie, Wei; Du, Shenglan; Yan, Shoulei; Li, Jie; Wang, Qingzhang

    2016-11-15

    Pretreatments such as low temperature blanching and/or calcium soaking affect the cooked texture of vegetal food. In the work, lotus rhizomes (Nelumbo nucifera Gaertn.) were pretreated using the following 4 treatments, blanching at 40°C, blanching at 90°C, soaking in 0.5% CaCl2, and blanching at 40°C followed by immersion in 0.5% CaCl2. Subsequently, the cell wall material of pretreated samples was isolated and fractioned to identify changes in the degree of esterification (DE) and monosaccharide content of each section, and the texture of the lotus rhizomes in different pre-treatments was determined after thermal processing with different time. The results showed that the greatest hardness was obtained after blanching at 40°C in CaCl2, possibly attributing to the formation of a pectate calcium network, which maintains the integrity of cell walls. Furthermore, the content of galactose, rhamnose and arabinose decreased due to the breakage of sugar backbones and subsequent damage to cell walls. Our results may provide a reference for lotus rhizome processing.

  18. Compositional, spectroscopic and rheological analyses of mucilage isolated from taro (Colocasia esculenta L. Schott) corms.

    Science.gov (United States)

    Njintang, Nicolas Yanou; Boudjeko, Thaddee; Tatsadjieu, Leopold Ngoune; Nguema-Ona, Eric; Scher, Joel; Mbofung, Carl M F

    2014-05-01

    Tropical roots and tubers generally contain mucilage. These mucilages exhibit unique rheological properties with considerable potential as a food thickener and stabilizer. A one-step extraction procedure was used to isolate starch free mucilage and associated proteins from a number of taro (Colocasia esculenta) varieties. The monosaccharide and amino acid composition, the structural and flow properties were investigated. The results showed that yield of mucilage fraction varied from 30 to 190 g.kg(-1). A negative correlation (r = -0.87; p < 0.05) was observed between the crude protein level and the yield. The monosaccharide profiles revealed that galactose, mannose and arabinose were the main monosaccharides in the hydrolysate of the mucilage. From the 17 amino acids analyzed, aspartic acid/asparagine (14.4-17.2%) and glutamic acid/glutamine (10.3-13.6%) were prominent in the mucilage as well as the flour. No significant differences were observed in the FT-IR spectra and in the viscosity behavior of the mucilage dispersions. The greatest difference in the mucilage is based on its monosaccharide profile while the protein composition, which reflects that of the flour, is relatively stable.

  19. Conversion of Aqueous Ammonia-Treated Corn Stover to Lactic Acid by Simultaneous Saccharification and Cofermentation

    Science.gov (United States)

    Zhu, Yongming; Lee, Y. Y.; Elander, Richard T.

    Treatment of corn stover with aqueous ammonia removes most of the structural lignin, whereas retaining the majority of the carbohydrates in the solids. After treatment, both the cellulose and hemicellulose in corn stover become highly susceptible to enzymatic digestion. In this study, corn stover treated by aqueous ammonia was investigated as the substrate for lactic acid production by simultaneous saccharification and cofermentation (SSCF). A commercial cellulase (Spezyme-CP) and Lactobacillus pentosus American Type Culture Collection (ATCC) 8041 (Spanish Type Culture Collection [CECT]-4023) were used for hydrolysis and fermentation, respectively. In batch SSCF operation, the carbohydrates in the treated corn stover were converted to lactic acid with high yields, the maximum lactic acid yield reaching 92% of the stoichiometric maximum based on total fermentable carbohydrates (glucose, xylose, and arabinose). A small amount of acetic acid was also produced from pentoses through the phosphoketolase pathway. Among the major process variables for batch SSCF, enzyme loading and the amount of yeast extract were found to be the key factors affecting lactic acid production. Further tests on nutrients indicated that corn steep liquor could be substituted for yeast extract as a nitrogen source to achieve the same lactic acid yield. Fed-batch operation of the SSCF was beneficial in raising the concentration of lactic acid to a maximum value of 75.0 g/L.

  20. Biochemical and functional properties of a lectin purified from korean large black soybeans--a cultivar of glycine max.

    Science.gov (United States)

    Fang, E F; Wong, J H; Lin, P; Ng, T B

    2010-06-01

    Lectins, a class of proteins that reversibly and non-enzymatically bind specific sugars, have been purified from different kinds of legumes. In this study, a 48-kDa lectin (KBL) was purified from Korean large black soybeans using liquid chromatography. The specific hemagglutinating activity of the KBL was 4096 titer/mg. EDTA-induced loss of hemagglutinating activity of KBL could be recovered by addition of Fe(3+) ions and some divalent cations as Ca(2+), Mn(2+), Fe(2+), Cu(2+), Zn(2+), and Pb(2+). Sugars such as D-(+)-galactose, D-(+)-raffinose, L-(+)-arabinose, alpha-D-(+)-melibiose, and alpha-lactose could inhibit the hemagglutinating activity of the lectin. Furthermore, the protein showed high thermal stability as well as stability over a wide range of pH values. KBL inhibited HIV-1 reverse transcriptase activity with an IC(50) of 1.38 microM. However, it was destitute of cytokine releasing, mitogenic, ribonuclease and antifungal activities. In addition, inhibitory activity toward nasopharyngeal cell lines was undetectable in KBL at concentrations up to 20 microM.

  1. tCRISPRi: tunable and reversible, one-step control of gene expression

    Science.gov (United States)

    Li, Xin-Tian; Jun, Yonggun; Erickstad, Michael J.; Brown, Steven D.; Parks, Adam; Court, Donald L.; Jun, Suckjoon

    2016-12-01

    The ability to control the level of gene expression is a major quest in biology. A widely used approach employs deletion of a nonessential gene of interest (knockout), or multi-step recombineering to move a gene of interest under a repressible promoter (knockdown). However, these genetic methods are laborious, and limited for quantitative study. Here, we report a tunable CRISPR-cas system, “tCRISPRi”, for precise and continuous titration of gene expression by more than 30-fold. Our tCRISPRi system employs various previous advancements into a single strain: (1) We constructed a new strain containing a tunable arabinose operon promoter PBAD to quantitatively control the expression of CRISPR-(d)Cas protein over two orders of magnitude in a plasmid-free system. (2) tCRISPRi is reversible, and gene expression is repressed under knockdown conditions. (3) tCRISPRi shows significantly less than 10% leaky expression. (4) Most important from a practical perspective, construction of tCRISPRi to target a new gene requires only one-step of oligo recombineering. Our results show that tCRISPRi, in combination with recombineering, provides a simple and easy-to-implement tool for gene expression control, and is ideally suited for construction of both individual strains and high-throughput tunable knockdown libraries.

  2. ISOLATION AND CHARACTERIZATION OF TRIACYLGLYCEROL ACCUMULATING MICROORGANISMS FOR BIODIESEL PRODUCTION

    Directory of Open Access Journals (Sweden)

    Sony Adhi Susanto

    2017-02-01

    Full Text Available Triacylglycerol is an important feedstock for biodiesel production. In this study, several strains of oleaginous bacteria were isolated from environmental sample based on their ability to grow on mineral salts medium supplemented with wood derived sugars such as cellulose, arabinose, xylose, mannose, and galactose. The lipid accumulating bacteria were selected on the basis of fluorescent signal from hydrophobic inclusion in the cytoplasm after incubation in selective medium containing lipophilic dye 0.5 % (w/v nile red. The lipid content was analyzed using thin layer chromatography (TLC and gas chromatography-mass spectrometry (GC-MS. In this study, three bacterial isolates 2HPCS1R4, 1LPCS2R2, and 1LPCS2R14 were selected among several studied candidates. TLC analysis of hydrophobic substance from 1LPCS2R2 and 1LPCS2R14 showed two overlapped discrete bands corresponded to triacylglycerol reference band, while 2HPCS1R4 displayed a faint band located above the reference band. GC-MS analysis confirmed that the bands consisted of fatty acid methyl esters with alkyl length varied from C12 to C17. Kinetic study showed that the fastest growing strain was 1LPCS2R2 had the highest growth rates and grown in glucose (µ = 0.29 h-1 and xylose (µ = 0.16 h-1 . In conclusion, this study has identified of prospective bacterial isolates for commercial biodiesel production

  3. Isolation, Nodulation and Characterization of Nodular Endophytes of Coriaria nepalensis

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Using the micro-dissection method, 273 actinomycete isolates were obtained from root nodules of Coriaria nepalensis. Twenty four Frankia-like isolates were shown to nodulate the host plants through pot experiment. Phenotypic characterization of ten isolates demonstrated that they were of the typical morpbologieal and cultural characteristics of the genus Frankia. These strains were divided into physiological group A, B and A/B where the latter was an intermediate group between the A and B strains. It was evident that group B but not A strains were able to nodulate the host. However, one strain of the group A/B unexpectedly nodulated the host. The utilization of carbon and nitrogen source for the strains was similar to other Frankia. Some strains were of type Ⅲ cell wall ; others were of type Ⅱ. Whole cell sugar patterns were diverse. Besides the common non-diagnostic sugars, most strains were shown to contain xylose and galactose, some contain xylose, galactose and arabinose and few contain galactose or xylose only. The G+C mol % of strains were ranging from 69 to 74.

  4. Structure and thermal property of alkaline hemicelluloses from steam exploded Phyllostachys pubescens.

    Science.gov (United States)

    Sun, Shao-Ni; Cao, Xue-Fei; Xu, Feng; Sun, Run-Cang; Jones, Gwynn Lloyd; Baird, Mark

    2014-01-30

    An environmentally friendly pretreatment process was developed to fractionate hemicelluloses from dried and water-immersed Phyllostachys pubescens chips by steam explosion followed with alkali and alkali/ethanol extractions. The detailed chemical and structural features of the isolated hemicellulosic fractions were comparatively investigated by HPAEC, GPC, FT-IR, (13)C NMR spectroscopies, and TGA analysis. It was found that the xylose/arabinose ratios of hemicelluloses obtained from alkali and alkali/ethanol extractions were 21.5-34.4 and 7.7-9.9, respectively, suggesting that hemicelluloses extracted with alkali had relatively lower degree of branches than those extracted with alkali/ethanol. Hemicellulosic fractions isolated from the water-immersed samples were obtained in high yields and exhibited similar compositions, which can be used as raw materials for production of value-added products. Furthermore, the hemicelluloses extracted with alkali had relatively higher molecular weight than those extracted with alkali/ethanol. In addition, an increment of incubation time resulted in a decreased thermal stability of hemicelluloses obtained from water-immersed sample.

  5. Producing high sugar concentrations from loblolly pine using wet explosion pretreatment.

    Science.gov (United States)

    Rana, Diwakar; Rana, Vandana; Ahring, Birgitte K

    2012-10-01

    We present quantitative analysis of pretreatment for obtaining high conversion and release of sugars from loblolly pine. We use wet explosion (WEx): wet oxidation followed by steam explosion and enzymatic hydrolysis (EH) at high dry matter to solubilize sugars. WEx was conducted at 25% (w/w) solids in presence of oxygen at pressures 6.5-7.2 bar, temperatures 170-175°C and residence time from 20 to 22.5 min. EH of pretreated samples was performed by Cellic® Ctec2 (60 mg protein/g cellulose) and Cellic® Htec2 enzymes (10% of Ctec2) at 50°C for 72 h. At the optimal WEx condition 96% cellulose and nearly 100% hemicellulose yield were obtained. The final concentrations of monomeric sugars were 152 g/L of glucose, 67 g/L of xylose, and 67 g/L of minor sugars (galactose, arabinose and mannose). Compared to previous work WEx seems to be superior for releasing high concentrations of monomeric sugars.

  6. Characterization of Lentinus edodes β-glucan influencing the in vitro starch digestibility of wheat starch gel.

    Science.gov (United States)

    Zhuang, Haining; Chen, Zhongqiu; Feng, Tao; Yang, Yan; Zhang, Jingsong; Liu, Guodong; Li, Zhaofeng; Ye, Ran

    2017-06-01

    Lentinus edodes β-glucan (abbreviated LEBG) was prepared from fruiting bodies of Lentinus edodes. The average molecular weight (Mw) and polydispersity index (Mw/Mn) of LEBG were measured to be 1.868×10(6)g/mol and 1.007, respectively. In addition, the monosaccharide composition of LEBG was composed of arabinose, galactose, glucose, xylose, mannose with a molar ratio of 5:11:18:644:16. After adding LEBG, both G' and G″ of starch gel increased. This is mainly because the connecting points between the molecular chains of LEBG and starch formed so that gel network structures were enhanced. The peak temperature in the heat flow diagram shifted to a higher temperature and the peak area of the endothermic enthalpy increased. Furthermore, LEBG can significantly inhibit starch hydrolysis. The predicted glycemic index (pGI) values were reduced when starch was replaced with LEBG at 20% (w/w). It might indicate that LEBG was suitable to develop low GI noodle or bread.

  7. In situ enzyme aided adsorption of soluble xylan biopolymers onto cellulosic material.

    Science.gov (United States)

    Chimphango, Annie F A; Görgens, J F; van Zyl, W H

    2016-06-05

    The functional properties of cellulose fibers can be modified by adsorption of xylan biopolymers. The adsorption is improved when the degree of biopolymers substitution with arabinose and 4-O-methyl-glucuronic acid (MeGlcA) side groups, is reduced. α-l-Arabinofuranosidase (AbfB) and α-d-glucuronidase (AguA) enzymes were applied for side group removal, to increase adsorption of xylan from sugarcane (Saccharum officinarum L) bagasse (BH), bamboo (Bambusa balcooa) (BM), Pinus patula (PP) and Eucalyptus grandis (EH) onto cotton lint. The AguA treatment increased the adsorption of all xylans by up to 334%, whereas, the AbfB increased the adsorption of the BM and PP by 31% and 44%, respectively. A combination of AguA and AbfB treatment increased the adsorption, but to a lesser extent than achieved with AguA treatment. This indicated that the removal of the glucuronic acid side groups provided the most significant increase in xylan adsorption to cellulose, in particular through enzymatic treatment.

  8. Optimization extraction of polysaccharide from Tunisian Zizyphus lotus fruit by response surface methodology: Composition and antioxidant activity.

    Science.gov (United States)

    Mkadmini Hammi, Khaoula; Hammami, Majdi; Rihouey, Christophe; Le Cerf, Didier; Ksouri, Riadh; Majdoub, Hatem

    2016-12-01

    Response surface methodology using a Box-Behnken design was employed to optimize extraction temperature, extraction time and ratio of water to material to obtain a maximum polysaccharide yield with high uronic acid content and antioxidant property from edible Zizyphus lotus fruit. The optimal conditions were: extraction time of 3h 15min, extraction temperature of 91.2°C and water to solid ratio of 39mL/g. Under these conditions, the experimental extraction yield, uronic acid content and 2,2-diphenyl-1-picrylhydrazyl scavenging ability (IC50) were 18.88%, 41.89 and 0.518mg/mL, respectively. Chemical analysis revealed that the extract was composed of 97.92% carbohydrate of which 41.89% is uronic acid. The extracted polysaccharides, with an average molecular weight of 2720kDa, are composed of arabinose, rhamnose, glucose, fructose, galactose and xylose. Moreover, the polysaccharides exhibited a significant reducing power and anti-lipid peroxidation activities.

  9. Effect of arabinogalactan proteins from the root caps of pea and Brassica napus on Aphanomyces euteiches zoospore chemotaxis and germination.

    Science.gov (United States)

    Cannesan, Marc Antoine; Durand, Caroline; Burel, Carole; Gangneux, Christophe; Lerouge, Patrice; Ishii, Tadashi; Laval, Karine; Follet-Gueye, Marie-Laure; Driouich, Azeddine; Vicré-Gibouin, Maïté

    2012-08-01

    Root tips of many plant species release a number of border, or border-like, cells that are thought to play a major role in the protection of root meristem. However, little is currently known on the structure and function of the cell wall components of such root cells. Here, we investigate the sugar composition of the cell wall of the root cap in two species: pea (Pisum sativum), which makes border cells, and Brassica napus, which makes border-like cells. We find that the cell walls are highly enriched in arabinose and galactose, two major residues of arabinogalactan proteins. We confirm the presence of arabinogalactan protein epitopes on root cap cell walls using immunofluorescence microscopy. We then focused on these proteoglycans by analyzing their carbohydrate moieties, linkages, and electrophoretic characteristics. The data reveal (1) significant structural differences between B. napus and pea root cap arabinogalactan proteins and (2) a cross-link between these proteoglycans and pectic polysaccharides. Finally, we assessed the impact of root cap arabinogalactan proteins on the behavior of zoospores of Aphanomyces euteiches, an oomycetous pathogen of pea roots. We find that although the arabinogalactan proteins of both species induce encystment and prevent germination, the effects of both species are similar. However, the arabinogalactan protein fraction from pea attracts zoospores far more effectively than that from B. napus. This suggests that root arabinogalactan proteins are involved in the control of early infection of roots and highlights a novel role for these proteoglycans in root-microbe interactions.

  10. Chemical composition and bioactivities of the marine alga Isochrysis galbana from Taiwan.

    Science.gov (United States)

    Yu, Chi-Cheng; Chen, Hsiao-Wei; Chen, Mao-Jing; Chang, Yu-Ching; Chien, Shih-Chang; Kuo, Yueh-Hsiung; Yang, Feng-Ling; Wu, Shih-Hsiung; Chen, Jie; Yu, Hsiao-Hui; Chao, Louis Kuop-Ping

    2010-12-01

    The present study investigated the chemical composition of Isochrysis galbana Parke, a marine microalga which is widely used as a feedstock in aquaculture. From gas chromatography/mass spectrometric analysis the mono-sugar compositions of I. galbana were 2.1% fucose, 2.5% rhamnose, 2.7% arabinose, 8.5% xylose, 15.7% mannose, 32.7% galactose and 35.8% glucose. The polysaccharides of I. galbana were able to induce prointerleukin-1beta (pro-IL-1beta) protein expression within murine macrophages. Furthermore, five kinds of chlorophyll and one sterol were separated from the ethanolic extracts, including pheophorbide-a, ethyl pheophorbide-a, 10S-10-hydroxypheophytin-a, 10R-10-hydroxypheophytin-a, (132-R)-pheophytin-a, and brassicasterol. In addition, the major soluble components of the ethanol/n-hexane extract were 9-octadecenoic acid (E) (38.4%), hexadecanoic acid (23.3%), tetradecanoic acid (15.7%), and octadecanoic acid (7.2%), but only a few polyunsaturated fatty acids were found, such as 9,12,15-octadecatrienoic acid (1.9%), 9,12-octadecadienoic acid (Z,Z) (3.4%), and docosahexaenoic acid (0.2%). This is the first occasion that polysaccharides from I. galbana have been demonstrated to exert immunomodulatory properties by the induction of IL-1 within macrophages.

  11. Isolation, Structural Characterization, and Valorization of Pectic Substances from Algerian Argan Tree Leaves (Argania spinosa (L. Skeels

    Directory of Open Access Journals (Sweden)

    Kadda Hachem

    2015-01-01

    Full Text Available Pectic polysaccharides were solubilized from Algerian argan tree leaves by sequential extraction with water at 100°C (water-soluble pectin; AL-WSP and EDTA solution at 80°C (chelating-soluble pectin; AL-CSP. Both AL-WSP and AL-CSP were rich in arabinose (28% and 74.5%, resp. and had a high content of uronic acid (38.5% and 21.5%, resp.. Pectic substances were deesterified and fractionated by anion exchange chromatography, giving five fractions for each extract. Most of the fractions were characterized by methylation analysis and then analyzed by 13C nuclear magnetic resonance spectroscopy. The results showed that AL-WSP consisted of rhamnogalacturonan type I, with arabinan and galactan branching at the O-4 position of the main rhamnose chain, while AL-CSP consisted of rhamnogalacturonan type I and a block of homogalacturonan. Antioxidant activities of AL-WSP and AL-CSP were evaluated by electronic spin resonance. The results showed that the antioxidant potential of AL-WSP (8.1% and AL-CSP (−1.2% was significantly lower than that of vitamin E.

  12. Phenotypic plasticity as indicator of no pioneer trees more tolerant to intense irradiance

    Directory of Open Access Journals (Sweden)

    Inayá Castiglioni Paradizo

    2015-12-01

    Full Text Available The occurrence of Cariniana legalis (Mart. Kuntze (Lecythidaceae in secondary forests in different levels of regeneration suggests that this species is more resistant to full sun in relation to Paratecoma peroba (Record. & Mell Kuhlm. (Bignoniaceae found in dense primary forest. The aim of this study was to characterize the plasticity of growth, anatomical and structural cell wall variables of C. legalis and P. peroba. As the stem is strong drain on tree, it was proposed the hypothesis that plasticity of lignin and hemicelluloses monosaccharides are higher than of growth and anatomical variables, especially with C. legalis that is more resistant to full sun as suggested by its ecological habit. Young plants with 14 months of age were subjected to 20 and 100% of solar light for 60 days. Unlike expected, the plasticity of lignin was lower than plasticity of growth and anatomic variables for both species. Hemicellulose composition of C. legalis was not affected by light. Proportion of arabinose was lower in P. peroba under full sun. We conclude that the indication of higher resistance of C. legalis to full sun was associated with plasticity index of net assimilation rate and relative growth rate (≥ 0.6, stomatal density (≥ 0.3 and lignins (≤ 0.2.

  13. Process for Assembly and Transformation into Saccharomyces cerevisiae of a Synthetic Yeast Artificial Chromosome Containing a Multigene Cassette to Express Enzymes That Enhance Xylose Utilization Designed for an Automated Platform.

    Science.gov (United States)

    Hughes, Stephen R; Cox, Elby J; Bang, Sookie S; Pinkelman, Rebecca J; López-Núñez, Juan Carlos; Saha, Badal C; Qureshi, Nasib; Gibbons, William R; Fry, Michelle R; Moser, Bryan R; Bischoff, Kenneth M; Liu, Siqing; Sterner, David E; Butt, Tauseef R; Riedmuller, Steven B; Jones, Marjorie A; Riaño-Herrera, Néstor M

    2015-12-01

    A yeast artificial chromosome (YAC) containing a multigene cassette for expression of enzymes that enhance xylose utilization (xylose isomerase [XI] and xylulokinase [XKS]) was constructed and transformed into Saccharomyces cerevisiae to demonstrate feasibility as a stable protein expression system in yeast and to design an assembly process suitable for an automated platform. Expression of XI and XKS from the YAC was confirmed by Western blot and PCR analyses. The recombinant and wild-type strains showed similar growth on plates containing hexose sugars, but only recombinant grew on D-xylose and L-arabinose plates. In glucose fermentation, doubling time (4.6 h) and ethanol yield (0.44 g ethanol/g glucose) of recombinant were comparable to wild type (4.9 h and 0.44 g/g). In whole-corn hydrolysate, ethanol yield (0.55 g ethanol/g [glucose + xylose]) and xylose utilization (38%) for recombinant were higher than for wild type (0.47 g/g and 12%). In hydrolysate from spent coffee grounds, yield was 0.46 g ethanol/g (glucose + xylose), and xylose utilization was 93% for recombinant. These results indicate introducing a YAC expressing XI and XKS enhanced xylose utilization without affecting integrity of the host strain, and the process provides a potential platform for automated synthesis of a YAC for expression of multiple optimized genes to improve yeast strains.

  14. Quantitative study of electrophoretic and electroosmotic enhancement during alternating current iontophoresis across synthetic membranes.

    Science.gov (United States)

    Yan, Guang; Li, S Kevin; Peck, Kendall D; Zhu, Honggang; Higuchi, William I

    2004-12-01

    One of the primary safety and tolerability limitations of direct current iontophoresis is the potential for electrochemical burns associated with the necessary current densities and/or application times required for effective treatment. Alternating current (AC) transdermal iontophoresis has the potential to eliminate electrochemical burns that are frequently observed during direct current transdermal iontophoresis. Although it has been demonstrated that the intrinsic permeability of skin can be increased by applying low-to-moderate AC voltages, transdermal transport phenomena and enhancement under AC conditions have not been systematically studied and are not well understood. The aim of the present work was to study the fundamental transport mechanisms of square-wave AC iontophoresis using a synthetic membrane system. The model synthetic membrane used was a composite Nuclepore membrane. AC frequencies ranging from 20 to 1000 Hz and AC fields ranging from 0.25 to 0.5 V/membrane were investigated. A charged permeant, tetraethyl ammonium, and a neutral permeant, arabinose, were used. The transport studies showed that flux was enhanced by increasing the AC voltage and decreasing AC frequency. Two theoretical transport models were developed: one is a homogeneous membrane model; the other is a heterogeneous membrane model. Experimental transport data were compared with computer simulations based on these models. Excellent agreement between model predictions and experimental data was observed when the data were compared with the simulations from the heterogeneous membrane model.

  15. Evaluation of physicochemical characteristics and antioxidant property of Prunus avium gum exudates.

    Science.gov (United States)

    Shabani, Hossein; Askari, Gholamreza; Jahanbin, Kambiz; Khodaeian, Faramarz

    2016-12-01

    In this study some physicochemical properties and elemental analysis of Prunus avium gum exudates were investigated. The gum studied had, on average, 75.14% carbohydrate, 11.3% uronic acids, 1.11% protein, 7.53% moisture content (w.b.) and 3.12% ash. Measured values for the angle of repose, Carr's index and Hausner ratio showed the good flow ability for the gum powder. The viscosity of 1% aqueous solution of the gum exhibited a Newtonian type of flow and with pH reduction the swelling index was increased. The average molecular weight of the main polysaccharide fraction was about 1.46×10(5)Da (146kDa). GC analysis showed that the main polysaccharide was composed of four kinds of neutral monosaccharides, namely mannose (Man), arabinose (Ara), galactose (Gal) and xylose (Xyl) with a relative molar ratio of 1.0:14.7:7.1:2.4. FTIR analysis showed the presence of carboxyl and hydroxyl groups and glycosidic linkage. The antioxidant activity of the gum was evaluated by determining DPPH scavenging and total phenolic contents which showed poor antioxidant property.

  16. Extraction and Composition Analysis of Polysaccharides in Bulbus lilii%百合多糖提取及成分分析

    Institute of Scientific and Technical Information of China (English)

    张国强; 杨正平

    2012-01-01

    采用水提醇沉法提取百合(Bulbus lilii)中的多糖成分,Sevage法除蛋白质,凝胶色谱法进行多糖纯化,制备3-甲基-1-苯基-2-吡唑啉酮(PMP)衍生物进行高效液相色谱分析.结果表明,百合多糖由鼠李糖、阿拉伯糖、葡萄糖、木糖、半乳糖5种单糖组成,其含量分别为4.82%、12.79%、47.02%、13.01%、22.36%.%Polysaccharide was extracted and isolated from Bulbus lilii by water extracting-alcohol precipitating method and purified by Sevage method and gel permeation chromatography. The components of the polysaccharide were identified and quantified by HPLC of the PMP derivatives. The results showed that the main monosaccharides contained in B. Lilii polysaccharide were rhamnose, arabinose, glucose, xylose and galactose, with content of 4.82%, 12.79%, 47.02%, 13.01% and 22.36%, respectively.

  17. Description of a PCR-based technique for DNA splicing and mutagenesis by producing 5' overhangs with run through stop DNA synthesis utilizing Ara-C

    Directory of Open Access Journals (Sweden)

    Silverman Mel

    2005-09-01

    Full Text Available Abstract Background Splicing of DNA molecules is an important task in molecular biology that facilitates cloning, mutagenesis and creation of chimeric genes. Mutagenesis and DNA splicing techniques exist, some requiring restriction enzymes, and others utilize staggered reannealing approaches. Results A method for DNA splicing and mutagenesis without restriction enzymes is described. The method is based on mild template-dependent polymerization arrest with two molecules of cytosine arabinose (Ara-C incorporated into PCR primers. Two rounds of PCR are employed: the first PCR produces 5' overhangs that are utilized for DNA splicing. The second PCR is based on polymerization running through the Ara-C molecules to produce the desired final product. To illustrate application of the run through stop mutagenesis and DNA splicing technique, we have carried out splicing of two segments of the human cofilin 1 gene and introduced a mutational deletion into the product. Conclusion We have demonstrated the utility of a new PCR-based method for carrying out DNA splicing and mutagenesis by incorporating Ara-C into the PCR primers.

  18. [Proposed neotype Streptomyces ruber (Krainsky, 1914) Waksman et Henrici, 1948].

    Science.gov (United States)

    Kuznetsov, V D; Filippova, S N; Poltorak, V A

    1987-01-01

    Culture 78 was proposed as a neotype of Streptomyces ruber. It was isolated from the soils of the Baikal region and was closest, in its taxonomic properties, to the original description of the species [13] whose representative had been lost. Cultures from different microbial collections designated as S. ruber were shown to be unlike the original description. The neotype had the following taxononic properties: the cell wall of type I; spiral sporophores with extended spirals having 2-3 coils; oval spores with a smooth envelope; greyish pink aerial and dark-red substrate mycelia; a red pigment not passing into the medium; slow gelatin liquefaction and milk peptonization; weak starch hydrolysis; assimilation of glucose, xylose, rammose, fructose, and inositol; weak growth on arabinose, raffinose and mannitol, but not on sucrose; no formation of melanoid pigments; synthesis of riboflavin and prodigiosin pigments; inhibition of Gram-positive bacterial and acid-resistant mycobacterial growth; no inhibition of yeast and fungal growth. The culture was sensitive to streptomycin, neomycin, gentamycin, monomycin, tetracycline,erythromycin, oleandomycin, lincomycin, ristomycin, levomycetin, polymyxin and fusidin, but resistant in penicillin. The population was composed of six variants [3]: main, faded, asporogenic red, asporogenic yellow, asporogenic white and nocardia-like. The latter two were not capable of riboflavin and prodigiosin formation. The asporogenic yellow variant was a monosynthetic organism: it formed riboflavin, but could not synthesize prodigiosin. The neotype of S. ruber 78 is deposited withthe national Collection of Microorganisms (the reference number is VKM A-611).

  19. Electrophysiological responses of differently diet-experienced Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) larvae to sugars and inositol%不同取食经历的棉铃虫幼虫对糖和肌醇的味觉电生理反应

    Institute of Scientific and Technical Information of China (English)

    曹欢; 汤清波; 马英; 詹欢; 赵新成; 闫凤鸣

    2013-01-01

    利用单感受器记录技术测定了不同取食经历的棉铃虫幼虫对糖和肌醇的电生理反应,以分析昆虫味觉细胞的可塑性.研究结果表明,(1)连续多代取食含量约39 mmol.L-1蔗糖的标准人工饲料的棉铃虫幼虫下颚中栓锥感器和侧栓锥感器对阿拉伯糖、海藻糖、麦芽糖、葡萄糖和蔗糖均产生明显的脉冲反应,但中栓锥感器对海藻糖和葡萄糖的反应频率显著高于侧栓锥感器,表明中栓锥感器内存在海藻糖和葡萄糖敏感细胞.(2)直接从田间采集的野生棉铃虫幼虫中栓锥感器对阿拉伯糖、麦芽糖、葡萄糖、蔗糖和肌醇脉冲反应的反应频率显著高于室内种群的反应频率,但2种群对海藻糖的反应频率没有显著差异,表明幼虫对海藻糖的反应机制不同于对蔗糖、肌醇和其他糖的反应机制.(3)连续多代取食标准人工饲料的棉铃虫幼虫中栓椎感器对阿拉伯糖、麦芽糖、葡萄糖、蔗糖和肌醇的电生理反应被抑制,但是当下一代幼虫取食不含蔗糖的人工饲料后,幼虫对这4种糖的反应频率恢复到野生种群的水平,而对肌醇的反应强度继续被抑制,表明幼虫对肌醇的反应机制不同于对阿拉伯糖、麦芽糖、葡萄糖和蔗糖的反应机制.这些结果表明幼虫前期取食经历能够显著影响后代对不同糖及肌醇的电生理反应,但是不同糖之间、糖与肌醇之间的反应机制存在差异.%The diet-induced plasticities of gustatory cells of larvae were investigated using single sensillum recording technology (SSR) by recording the gustatory electrophysiological responses to 5 sugars and inositol in Helicoverpa armigera with differently dietary experiences.The results showed as follows:(1) frequencies of electrophysiological responses to sucrose,D-(+)-glucose,maltose,(D-(+)-trehalose dehydrate,D-arabinose and inositol in both styloconic sensilla of larvae with sucrose-feed experiences for

  20. Genomic analysis of six new Geobacillus strains reveals highly conserved carbohydrate degradation architectures and strategies

    Directory of Open Access Journals (Sweden)

    Phillip eBrumm

    2015-05-01

    Full Text Available In this work we report the whole genome sequences of six new Geobacillus xylanolytic strains along with the genomic analysis of their capability to degrade carbohydrates.. The six sequenced Geobacillus strains described here have a range of GC contents from 43.9% to 52.5% and clade with named Geobacillus species throughout the entire genus. We have identified a ~200 kb unique super-cluster in all six strains, containing five to eight distinct carbohydrate degradation clusters in a single genomic region, a feature not seen in other genera. The Geobacillus strains rely on a small number of secreted enzymes located within distinct clusters for carbohydrate utilization, in contrast to most biomass-degrading organisms which contain numerous secreted enzymes located randomly throughout the genomes. All six strains are able to utilize fructose, arabinose, xylose, mannitol, gluconate, xylan, and α-1,6-glucosides. The gene clusters for utilization of these seven substrates have identical organization and the individual proteins have a high percent identity to their homologs. The strains show significant differences in their ability to utilize inositol, sucrose, lactose, α-mannosides, α-1,4-glucosides and arabinan.

  1. Gastro protective and H(+), K(+)-ATPase/H. pylori inhibitory properties of pectic polysaccharides from potato.

    Science.gov (United States)

    Badanavalu Chandrashekar, Kavitha; Dharmesh, Shylaja Mallaiah

    2016-03-01

    Polysaccharide is one among the important classes of biological polymers that is reported to exhibit disease preventive properties. The present study describes the isolation of galactans and confirmation of the same by sugar analysis and determination of anti-ulcer effect of Potato Galactan Polysaccharide (PGP). Data indicated that PGP possessed sugar composition of rhamnose (2%), arabinose (3%), mannose (3%), galactose (94%) and uronic acid (17%) confirming that PGP thus isolated is a galactan. PGP exhibited potent H(+), K(+)-ATPase inhibitory activity (IC50 420 μg/mL) in vitro as opposed to lansoprazole, a known antiulcer drug with IC50 19.3 μg/mL. The antiulcer potency of PGP was evaluated in ethanol stress induced gastric ulcer model in vivo. About 84% reduction in ulcer index; enhanced mucosal recovery, normalization of H(+), K(+)-ATPase, antioxidant and antioxidant enzymes substantiated the antiulcer potentials of PGP. Mucosal recovery could be attributed to cytoprotective and DNA protective ability of PGP that can help in mucosal layer regeneration. Further, PGP was also effective in inhibiting Helicobacter pylori as per growth inhibition assay followed by scanning electron microscopic studies suggesting that PGP is effective in curbing the growth of H. pylori, which is responsible for ∼70% of gastric ulcer/cancer incidences.

  2. Design and synthesis of biotin analogues reversibly binding with streptavidin.

    Science.gov (United States)

    Yamamoto, Tomohiro; Aoki, Kiyoshi; Sugiyama, Akira; Doi, Hirofumi; Kodama, Tatsuhiko; Shimizu, Yohei; Kanai, Motomu

    2015-04-01

    Two new biotin analogues, biotin carbonate 5 and biotin carbamate 6, have been synthesized. These molecules were designed to reversibly bind with streptavidin by replacing the hydrogen-bond donor NH group(s) of biotin's cyclic urea moiety with oxygen. Biotin carbonate 5 was synthesized from L-arabinose (7), which furnishes the desired stereochemistry at the 3,4-cis-dihydroxy groups, in 11% overall yield (over 10 steps). Synthesis of biotin carbamate 6 was accomplished from L-cysteine-derived chiral aldehyde 33 in 11% overall yield (over 7 steps). Surface plasmon resonance analysis of water-soluble biotin carbonate analogue 46 and biotin carbamate analogue 47 revealed that KD values of these compounds for binding to streptavidin were 6.7×10(-6)  M and 1.7×10(-10)  M, respectively. These values were remarkably greater than that of biotin (KD =10(-15)  M), and thus indicate the importance of the nitrogen atoms for the strong binding between biotin and streptavidin.

  3. Production, Purification, and in Vitro Evaluation of the Prebiotic Potential of Arabinoxylooligosaccharides from Brewer's Spent Grain.

    Science.gov (United States)

    Gómez, Belén; Míguez, Beatriz; Veiga, Adán; Parajó, Juan Carlos; Alonso, José Luís

    2015-09-30

    Brewer's spent grain (BSG) samples were subjected to a two-step aqueous processing (starch extraction and autohydrolysis) in order to assess their potential as a raw material for obtaining a mixture of arabinoxylooligosaccharides (AXOS) suitable to be use as prebiotics for elderly. After hydrothermal treatment, the liquors were refined by a sequence of purification and conditioning steps including membrane filtration, enzymatic hydrolysis, and ion exchange. The presence of both substituted (degree of polimerization (DP) = 2-10) and unsubstituted (DP = 2-16) oligosaccharides made up of xylose and arabinose (AXOS) were confirmed in purified mixtures (in which total OS content = 84% w/w) by using chromatographic techniques and matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS). Finally, AXOS were evaluated for their prebiotic activity by in vitro fermentation assays using fecal inocula from elderly people, demonstrating that AXOS were slightly better substrates than FOS, in terms of bacterial population shifts as in the production of SCFA.

  4. Production of exopolysaccharides from a thermophilic microorganism isolated from a marine hot spring in flegrean areas.

    Science.gov (United States)

    Schiano Moriello, V; Lama, L; Poli, A; Gugliandolo, C; Maugeri, T L; Gambacorta, A; Nicolaus, B

    2003-02-01

    A thermophilic strain isolated from sea sand at Maronti, near Sant' Angelo (Ischia), is described. The organism grows well at an optimal temperature of 60 degrees C at pH 7.0. The thermophilic bacterium, named strain 4004, produces an exocellular polysaccharide (EPS) in yields of 90 mg/l. The EPS fraction was produced with all substrates tested, although a higher yield was obtained with sucrose or trehalose as sole carbon source. During growth, the EPS content was proportional to the biomass. Three fractions (EPS1, EPS2, EPS3) were obtained after purification. Quantitative monosaccharide analysis of the EPSs revealed the presence of mannose:glucose:galactose in a relative ratio of 0.5:1.0:0.3 in EPS1, mannose:glucose:galactose in a relative ratio of 1.0:0.3:trace in EPS2, and galactose:mannose:glucosamine:arabinose in a relative ratio of 1.0:0.8:0.4:0.2 in EPS3. The average molecular mass of EPS3 was determined to be 1x10(6) Da. From comparison of the chemical shift values in (1)H and (13)C spectra, we conclude that EPS3 presents a pentasaccharide repeating unit.

  5. Biohydrogen Production from Xylose by Aanaerobic Mixed Cultures in Elephant Dung

    Directory of Open Access Journals (Sweden)

    Khanittha FIALA

    2014-05-01

    Full Text Available Xylose was used to produce hydrogen by anaerobic mixed cultures in elephant dung. The elephant dung was subjected to heat shock (90 ºC for 3 h and acid (pH 3.0 - 4.0 for 24 h followed by neutralization pretreatments before using it as a seed inoculum. The results showed that the seed inoculum pretreatment by heat shock produced higher hydrogen gas than acid seed inoculum pretreatment, while untreated seed inoculum gave the lowest hydrogen production. Therefore, seed inoculum by heat shock was suitable for hydrogen production from xylose, arabinose and glucose. It was found that xylose was a preferred pentose sugar for hydrogen production, in which the results were comparable to those of glucose. The initial pH of 8.0 was found to be optimal for hydrogen production from xylose, in which a maximum hydrogen production of 371 mL H2/g VSS and a yield of 1.62 mol H2/mol xylose were obtained. Microbial community analysis by denaturing gradient gel electrophoresis (DGGE revealed that, under the optimum initial pH of 8.0, the predominant hydrogen producers were Clostridium acetobutylicum and Ethanoligenens sp. In addition, lactic acid bacteria i.e. Bifidobacterium minimum and Bifidobacterium sp. were observed, which coincided with the small amount of lactic acid detected at this optimum initial pH.

  6. Construction and validation of metagenomic DNA libraries from landfarm soil microorganisms.

    Science.gov (United States)

    Pessoa, T B A; de Souza, S S; Cerqueira, A F; Rezende, R P; Pirovani, C P; Dias, J C T

    2013-06-28

    Landfarming biodegradation is a strategy used by the petrochemical industry to reduce pollutants in petroleum-contaminated soil. We constructed 2 metagenomic libraries from landfarming soil in order to determine the pathway used for mineralization of benzene and to examine protein expression of the bacteria in these soils. The DNA of landfarm soil, collected from Ilhéus, BA, Brazil, was extracted and a metagenomic library was constructed with the Copy Control(TM) Fosmid Library Production Kit, which clones 25-45-kb DNA fragments. The clones were selected for their ability to express enzymes capable of cleaving aromatic compounds. These clones were grown in Luria-Bertani broth plus L-arabinose, benzene, and chloramphenicol as induction substances; they were tested for activity in the catechol cleavage pathway, an intermediate step in benzene degradation. Nine clones were positive for ortho-cleavage and one was positive for meta-cleavage. Protein band patterns determined by SDS-polyacrylamide gel electrophoresis differed in bacteria grown on induced versus non-induced media (Luria-Bertani broth). We concluded that the DNA of landfarm soil is an important source of genes involved in mineralization of xenobiotic compounds, which are common in gasoline and oil spills. Metagenomic library allows identification of non-culturable microorganisms that have potential in the bioremediation of contaminated sites.

  7. Leaf-cutter ant fungus gardens are biphasic mixed microbial bioreactors that convert plant biomass to polyols with biotechnological applications.

    Science.gov (United States)

    Somera, Alexandre F; Lima, Adriel M; Dos Santos-Neto, Álvaro J; Lanças, Fernando M; Bacci, Maurício

    2015-07-01

    Leaf-cutter ants use plant matter to culture the obligate mutualistic basidiomycete Leucoagaricus gongylophorus. This fungus mediates ant nutrition on plant resources. Furthermore, other microbes living in the fungus garden might also contribute to plant digestion. The fungus garden comprises a young sector with recently incorporated leaf fragments and an old sector with partially digested plant matter. Here, we show that the young and old sectors of the grass-cutter Atta bisphaerica fungus garden operate as a biphasic solid-state mixed fermenting system. An initial plant digestion phase occurred in the young sector in the fungus garden periphery, with prevailing hemicellulose and starch degradation into arabinose, mannose, xylose, and glucose. These products support fast microbial growth but were mostly converted into four polyols. Three polyols, mannitol, arabitol, and inositol, were secreted by L. gongylophorus, and a fourth polyol, sorbitol, was likely secreted by another, unidentified, microbe. A second plant digestion phase occurred in the old sector, located in the fungus garden core, comprising stocks of microbial biomass growing slowly on monosaccharides and polyols. This biphasic operation was efficient in mediating symbiotic nutrition on plant matter: the microbes, accounting for 4% of the fungus garden biomass, converted plant matter biomass into monosaccharides and polyols, which were completely consumed by the resident ants and microbes. However, when consumption was inhibited through laboratory manipulation, most of the plant polysaccharides were degraded, products rapidly accumulated, and yields could be preferentially switched between polyols and monosaccharides. This feature might be useful in biotechnology.

  8. WOOD HEMICELLULOSE/CHITOSAN-BASED SEMI-INTERPENETRATING NETWORK HYDROGELS: MECHANICAL, SWELLING AND CONTROLLED DRUG RELEASE PROPERTIES

    Directory of Open Access Journals (Sweden)

    Muzaffer Ahmet Karaaslan

    2010-04-01

    Full Text Available The cell wall of most plant biomass from forest and agricultural resources consists of three major polymers, cellulose, hemicellulose, and lignin. Of these, hemicelluloses have gained increasing attention as sustainable raw materials. In this study, novel pH-sensitive semi-IPN hydrogels based on hemicelluloses and chitosan were prepared using glutaraldehyde as the crosslinking agent. The hemicellulose isolated from aspen was analyzed for sugar content by HPLC, and its molecular weight distribution was determined by high performance size exclusion chromatography. Results revealed that hemicellulose had a broad molecular weight distribution with a fair amount of polymeric units, together with xylose, arabinose, and glucose. The effects of hemicellulose content on mechanical properties and swelling behavior of hydrogels were investigated. The semi-IPNs hydrogel structure was confirmed by FT-IR, X-ray study, and the ninhydrin assay method. X-ray analysis showed that higher hemicellulose contents yielded higher crystallinity. Mechanical properties were mainly dependent on the crosslink density and average molecular weight between crosslinks. Swelling ratios increased with increasing hemicellulose content and were high at low pH values due to repulsion between similarly charged groups. In vitro release study of a model drug showed that these semi-IPN hydrogels could be used for controlled drug delivery into gastric fluid.

  9. Crude dietary polysaccharide fraction isolated from jackfruit enhances immune system activity in mice.

    Science.gov (United States)

    Tan, Yin-Feng; Li, Hai-Long; Lai, Wei-Yong; Zhang, Jun-Qing

    2013-07-01

    Crude polysaccharides (PSs) were isolated from the fruit pulp of jackfruit, and their chemical composition determined and evaluated for an immune regulatory activity in mice. The PSs were isolated from water extracts of jackfruit pulp (JFP) using the ethanol precipitation method. The resulting precipitates were further purified by dialysis and protein depletion by the Sevage method. The phenol-sulfuric method was used to determine the content of the PSs. The composition of PSs was determined by the Sephadex-G200 column chromatography and high-performance liquid chromatography methods. The thymus index and macrophage phagocytic function methods in mice were used to evaluate the immune regulatory activity of JFP-PSs. The JFP-PSs content in jackfruit was about 21% (w/w) and the yield of crude PSs was 3.91%. The single molecular mass weight PS was the main constituent of JFP-PSs. The major monosaccharide residues were rhamnose, glucose, galactose, and arabinose. The JFP-PSs enhanced the thymus weight index and the phagocytic rate after 30 days of subchronic p.o. administration to mice at 4.5 mg/kg. The JFP contains single molecular PS and JFP-PS has immune-stimulating activities in mice. These data suggest that at least some of the traditional uses of JFP can be ascribed to its immunomodulatory effects.

  10. Cotton GalT1 encoding a putative glycosyltransferase is involved in regulation of cell wall pectin biosynthesis during plant development.

    Science.gov (United States)

    Qin, Li-Xia; Rao, Yue; Li, Long; Huang, Jun-Feng; Xu, Wen-Liang; Li, Xue-Bao

    2013-01-01

    Arabinogalactan proteins (AGPs), are a group of highly glycosylated proteins that are found throughout the plant kingdom. To date, glycosyltransferases that glycosylate AGP backbone have remained largely unknown. In this study, a gene (GhGalT1) encoding a putative β-1,3-galactosyltransferase (GalT) was identified in cotton. GhGalT1, belonging to CAZy GT31 family, is the type II membrane protein that contains an N-terminal transmembrane domain and a C-terminal galactosyltransferase functional domain. A subcellular localization assay demonstrated that GhGalT1 was localized in the Golgi apparatus. RT-PCR analysis revealed that GhGalT1 was expressed at relatively high levels in hypocotyls, roots, fibers and ovules. Overexpression of GhGalT1 in Arabidopsis promoted plant growth and metabolism. The transgenic seedlings had much longer primary roots, higher chlorophyll content, higher photosynthetic efficiency, the increased biomass, and the enhanced tolerance to exogenous D-arabinose and D-galactose. In addition, gas chromatography (GC) analysis of monosaccharide composition of cell wall fractions showed that pectin was changed in the transgenic plants, compared with that of wild type. Three genes (GAUT8, GAUT9 and xgd1) involved in pectin biosynthesis were dramatically up-regulated in the transgenic lines. These data suggested that GhGalT1 may be involved in regulation of pectin biosynthesis required for plant development.

  11. Non-cellulosic polysaccharides from cotton fibre are differently impacted by textile processing.

    Science.gov (United States)

    Runavot, Jean-Luc; Guo, Xiaoyuan; Willats, William G T; Knox, J Paul; Goubet, Florence; Meulewaeter, Frank

    2014-01-01

    Cotton fibre is mainly composed of cellulose, although non-cellulosic polysaccharides play key roles during fibre development and are still present in the harvested fibre. This study aimed at determining the fate of non-cellulosic polysaccharides during cotton textile processing. We analyzed non-cellulosic cotton fibre polysaccharides during different steps of cotton textile processing using GC-MS, HPLC and comprehensive microarray polymer profiling to obtain monosaccharide and polysaccharide amounts and linkage compositions. Additionally, in situ detection was used to obtain information on polysaccharide localization and accessibility. We show that pectic and hemicellulosic polysaccharide levels decrease during cotton textile processing and that some processing steps have more impact than others. Pectins and arabinose-containing polysaccharides are strongly impacted by the chemical treatments, with most being removed during bleaching and scouring. However, some forms of pectin are more resistant than others. Xylan and xyloglucan are affected in later processing steps and to a lesser extent, whereas callose showed a strong resistance to the chemical processing steps. This study shows that non-cellulosic polysaccharides are differently impacted by the treatments used in cotton textile processing with some hemicelluloses and callose being resistant to these harsh treatments.

  12. Relationship between pollination and cell wall properties in common fig fruit.

    Science.gov (United States)

    Trad, Mehdi; Ginies, Christian; Gaaliche, Badii; Renard, Catherine M G C; Mars, Messaoud

    2014-02-01

    Most botanical types in fig Ficus carica require pollination to fulfil their development and ensure quality onset of the fruit. Cell wall behaviour and composition was followed in fig fruit in response to pollination during maturity. Figs, when ripe, soften drastically and lose of their firmness and cell wall cohesion. Pollination increased peel thickness, flesh thickness, fresh weight and dry matter content of the fruit. Alcohol insoluble solids (AIS), more concentrated in the flesh tissue, were not influenced by the lack of pollination. Concentrations in uronic acids were higher in the AIS of the peel than that of the flesh and differences were significant between pollinated and non-pollinated fruits. Pectin polymers in figs were high methylated (DM>50). The methylation degree (DM) increased more with pollination affecting textural properties of the fig receptacle. The major neutral sugars from the AIS were glucose (Glc) from cellulose followed by arabinose (Ara). No significant changes in neutral sugars content could be allocated to pollination. Pollination is essential in fruit enlargement and softening. Minor changes were determined in the cell wall composition of the fruit at maturity. Fertile seeds resulting from pollination may possibly take place in hormonal activity stimulating many related enzymes of the wall matrix depolymerisation in particular polygalacturonase (PG) and pectin methylesterase (PME).

  13. Efficiency of Conditionally Attenuated Salmonella enterica Serovar Typhimurium in Bacterium-Mediated Tumor Therapy

    Science.gov (United States)

    Frahm, Michael; Kocijancic, Dino; Rohde, Manfred; Hensel, Michael; Curtiss, Roy; Erhardt, Marc; Weiss, Siegfried

    2015-01-01

    ABSTRACT Increasing numbers of cancer cases generate a great urge for new treatment options. Applying bacteria like Salmonella enterica serovar Typhimurium for cancer therapy represents an intensively explored option. These bacteria have been shown not only to colonize solid tumors but also to exhibit an intrinsic antitumor effect. In addition, they could serve as tumor-targeting vectors for therapeutic molecules. However, the pathogenic S. Typhimurium strains used for tumor therapy need to be attenuated for safe application. Here, lipopolysaccharide (LPS) deletion mutants (ΔrfaL, ΔrfaG, ΔrfaH, ΔrfaD, ΔrfaP, and ΔmsbB mutants) of Salmonella were investigated for efficiency in tumor therapy. Of such variants, the ΔrfaD and ΔrfaG deep rough mutants exhibited the best tumor specificity and lowest pathogenicity. However, the intrinsic antitumor effect was found to be weak. To overcome this limitation, conditional attenuation was tested by complementing the mutants with an inducible arabinose promoter. The chromosomal integration of the respective LPS biosynthesis genes into the araBAD locus exhibited the best balance of attenuation and therapeutic benefit. Thus, the present study establishes a basis for the development of an applicably cancer therapeutic bacterium. PMID:25873375

  14. WR-2721 entry into the brain across a modified blood-brain barrier

    Energy Technology Data Exchange (ETDEWEB)

    Lamperti, A.; Conger, A.D.; Jenkins, O.; Cohen, G.; Rizzo, A.; Davis, M.E.; Sodicoff, M.

    1988-08-01

    Radioprotection of the CNS by WR-2721 has not been possible because of its inability to cross the blood-brain barrier (BBB) and so gain access to the neural tissue. Modification of the BBB using hypertonic arabinose (1.8 m), injected via the internal carotid artery (ica), permitted entry of ip-injected (/sup 14/C)WR-2721 into the ipsilateral cerebral hemisphere. The BBB-modified hemisphere had a 5.34-fold increased uptake compared to nonmodified controls. Delivery as a bolus via the ica further enhanced uptake after BBB opening; WR-2721 was 3.73 times greater than by ip injection. A 20-fold increase of WR-2721 brain uptake has been calculated for ica administration with the BBB opened as compared to the ip route without BBB modification. Toxicity of ip-administered WR-2721 with the BBB open was only 1.4 times greater than non-modified controls and 1.96 times more toxic when delivered via the ica. These data demonstrate significant uptake of WR-2721 into the CNS, a previously unprotected organ, and provide a model for future radioprotective studies.

  15. Isolation, chemical characterization and biological activity of alfalfa (Medicago media Pers. root saponins

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    Wiesław Oleszek

    2014-01-01

    Full Text Available Saponins from alfalfa (Medicago media Pers. roots were isolated and their acid hydrolysis revealed several aglycones that were obtained in crystalline form and characterized. Medicagenic acid, hederagenin and soyasapogenols A. B, C. D, E and F were found. Crude saponins were separated into cholesterol-precipitable and nonprecipitable fractions. The precipitable fraction consisted of medicagenic acid glycosides: glucose, arabinose, xylose and rhamnose were found as their sugar chain components. The nonprecipitable fraction was a mixture of hederagenine and soyasapogenol glycosides, and glucose arthinose. xylose. galactose and glucuronic acid were found in the sugar component,. 7 he medicagenic acid glycosides made up 6% of root dry matter and showed high biological activity. They cuased red blood cells lysis (haemolytic index 3000, completely inhibited Trichoderma viride growth at the concentration of 2.5 Mg. 100 cm-3 of growth medium and retarded wheat seedling growth at concentrations as low as 100 ppm. The cholesterol-nonprecipitable fraction caused no blood cell lysis and fungus growth inhibition, although it did inhibit seedling growth, but to a much lesser extent than medicagenic acrd glycosides. The detrimental effect of alfalfa root saponins on winter wheat crop after alfalfa is discussed.

  16. Nutritional value-dependent and nutritional value-independent effects on Drosophila melanogaster larval behavior.

    Science.gov (United States)

    Rohwedder, Astrid; Pfitzenmaier, Johanna E; Ramsperger, Noel; Apostolopoulou, Anthi A; Widmann, Annekathrin; Thum, Andreas S

    2012-10-01

    Gustatory stimuli allow an organism not only to orient in its environment toward energy-rich food sources to maintain nutrition but also to avoid unpleasant or even poisonous substrates. For both mammals and insects, sugars-perceived as "sweet"-potentially predict nutritional benefit. Interestingly, even Drosophila adult flies are attracted to most high-potency sweeteners preferred by humans. However, the gustatory information of a sugar may be misleading as some sugars, although perceived as "sweet," cannot be metabolized. Accordingly, in adult Drosophila, a postingestive system that additionally evaluates the nutritional benefit of an ingested sugar has been shown to exist. By using a set of seven different sugars, which either offer (fructose, sucrose, glucose, maltodextrin, and sorbitol) or lack (xylose and arabinose) nutritional benefit, we show that Drosophila, at the larval stage, can perceive and evaluate sugars based on both nutrition-dependent and -independent qualities. In detail, we find that larval survival and feeding mainly depend on the nutritional value of a particular sugar. In contrast, larval choice behavior and learning are regulated in a more complex way by nutrition value-dependent and nutrition value-independent information. The simplicity of the larval neuronal circuits and their accessibility to genetic manipulation may ultimately allow one to identify the neuronal and molecular basis of the larval sugar perception systems described here behaviorally.

  17. Drosophila evaluates and learns the nutritional value of sugars.

    Science.gov (United States)

    Fujita, Michiko; Tanimura, Teiichi

    2011-05-10

    Living organisms need to search for and ingest nutritional chemicals, and gustation plays a major role in detecting and discriminating between chemicals present in the environment. Using Drosophila as a model organism, we asked whether animals have the ability to evaluate the nutritional value of sugars. In flies, chemosensilla on the tarsi and labellum are the gustatory organs used to discriminate between edible and nonedible compounds [1, 2]. We noticed that Drosophila do not assign nutritional values to all sweet chemicals. D-arabinose is sweet to flies, but it provides them with no nutrition. By contrast, the sugar alcohol D-sorbitol is not sensed as sweet, but flies can live on it. We performed behavioral and electrophysiological measurements to confirm these gustatory and feeding responses. We found that Drosophila can learn the nutritional value of nonsweet D-sorbitol when it is associated with an odor cue. The learning process involved the synapsin molecule, suggesting that a neuronal mechanism is involved. We propose that Drosophila uses neural machinery to detect, evaluate, and learn the nutritional value of foods after ingestion.

  18. Purification and characterization of a novel polysaccharide-peptide complex from Clinacanthus nutans Lindau leaves.

    Science.gov (United States)

    Huang, Danmin; Li, Yunhong; Cui, Fengjie; Chen, Jun; Sun, Jiamin

    2016-02-10

    A novel polysaccharide-peptide complex CNP-1-2 with molecular weight of 9.17 × 10(4) Da was obtained from Clinacanthus nutans Lindau leaves by hot water extraction, ethanol precipitation, and purification with Superdex 200 and DEAE-Sepharose Fast Flow column chromatography. CNP-1-2 exhibited the highest growth inhibitory effect on human gastric cancer cells SGC-7901 with inhibition ratio of 92.34% and stimulated activation of macrophages with NO secretion level of 47.53 μmol/L among the polysaccharide fractions. CNP-1-2 comprised approximately 87.25% carbohydrate and 9.37% protein. Monosaccharide analysis suggested that CNP-1-2 was composed of L-rhamnose, l-arabinose, D-mannose, D-glucose and D-galactose with a molar ratio of 1.30:1.00:2.56:4.95:5.09. Methylation analysis, FT-IR, and (1)H NMR spectroscopy analysis revealed that CNP-1-2 might have a backbone consisting of 1,4-linked Glcp, 1,3-linked Glcp, 1,3-linked Manp, 1,4-linked Galp, 1,2,6-linked Galp and 1,2,6-linked Galp. Its side chain might be composed of 1-linked Araf, 1,6-linked Galp and 1-linked Rhap residues. AFM (atomic force micrograph) analysis revealed that CNP-1-2 had the molecular aggregation along with branched and entangled structure.

  19. Sugar-rich sweet sorghum is distinctively affected by wall polymer features for biomass digestibility and ethanol fermentation in bagasse.

    Science.gov (United States)

    Li, Meng; Feng, Shengqiu; Wu, Leiming; Li, Ying; Fan, Chunfen; Zhang, Rui; Zou, Weihua; Tu, Yuanyuan; Jing, Hai-Chun; Li, Shizhong; Peng, Liangcai

    2014-09-01

    Sweet sorghum has been regarded as a typical species for rich soluble-sugar and high lignocellulose residues, but their effects on biomass digestibility remain unclear. In this study, we examined total 63 representative sweet sorghum accessions that displayed a varied sugar level at stalk and diverse cell wall composition at bagasse. Correlative analysis showed that both soluble-sugar and dry-bagasse could not significantly affect lignocellulose saccharification under chemical pretreatments. Comparative analyses of five typical pairs of samples indicated that DP of crystalline cellulose and arabinose substitution degree of non-KOH-extractable hemicelluloses distinctively affected lignocellulose crystallinity for high biomass digestibility. By comparison, lignin could not alter lignocellulose crystallinity, but the KOH-extractable G-monomer predominately determined lignin negative impacts on biomass digestions, and the G-levels released from pretreatments significantly inhibited yeast fermentation. The results also suggested potential genetic approaches for enhancing soluble-sugar level and lignocellulose digestibility and reducing ethanol conversion inhibition in sweet sorghum.

  20. Covalently Cross-Linked Arabinoxylans Films for Debaryomyces hansenii Entrapment

    Directory of Open Access Journals (Sweden)

    Ramsés González-Estrada

    2015-06-01

    Full Text Available In the present study, wheat water extractable arabinoxylans (WEAX were isolated and characterized, and their capability to form covalently cross-linked films in presence of Debaryomyces hansenii was evaluated. WEAX presented an arabinose to xylose ratio of 0.60, a ferulic acid and diferulic acid content of 2.1 and 0.04 µg∙mg−1 WEAX, respectively and a Fourier Transform Infra-Red (FT-IR spectrum typical of WEAX. The intrinsic viscosity and viscosimetric molecular weight values for WEAX were 3.6 dL∙g−1 and 440 kDa, respectively. The gelation of WEAX (1% w/v with and without D. hansenii (1 × 107 CFU∙cm−2 was rheologically investigated by small amplitude oscillatory shear. The entrapment of D. hansenii decreased gel elasticity from 1.4 to 0.3 Pa, probably by affecting the physical interactions between WEAX chains. Covalently cross-linked WEAX films containing D. hansenii were prepared by casting. Scanning electron microscopy images show that WEAX films containing D. hansenii were porous and consisted of granular-like and fibre microstructures. Average tensile strength, elongation at break and Young’s modulus values dropped when D. hansenii was present in the film. Covalently cross-lined WEAX containing D. hansenii could be a suitable as a functional entrapping film.

  1. Low viscosity hydrogel of guar gum: preparation and physicochemical characterization.

    Science.gov (United States)

    Cunha, Pablyana L R; Castro, Rondinelle R; Rocha, Francisco A C; de Paula, Regina C M; Feitosa, Judith P A

    2005-10-30

    Guar gum was cross-linked with glutaraldehyde and characterized by GPC, rheology, WADX, SEM and TGA. This guar gum is a galactomannan polysaccharide, that contains small amount of arabinose, glucose and uronic acid, besides galactose and mannose. The polymer has high molar mass, with Mw, Mn and Mv values of 2.0x10(6), 1.2x10(6) and 1.9x10(6)g/mol, respectively. The reticulation follows a slow process and lead to a viscosity increase of 40 times compared with the original gum solution. The final viscosity was similar to that of Hylan G-F 20, a hyaluronate derivative, commercially used in viscosupplementation treatment. The gel contains 95.6% of water and the amount of residual glutaraldehyde is much lower than the LD-50. Porous structure was detected by SEM and thermal stability was improved by the cross-linking. The low viscosity, the small amount of remained glutaraldehyde, and the thermal stability indicates that the guar hydrogel has potential to be applied as biomaterial with specific rheological requirements.

  2. Structural and physicochemical characteristics of a novel water-soluble gum from Lallemantia royleana seed.

    Science.gov (United States)

    Razavi, Seyed Mohammad Ali; Cui, Steve W; Ding, Huihuang

    2016-02-01

    In this study, the structural information (monosaccharide compositions, molecular weight parameters & FTIR analysis), chemical composition (moisture, protein, ash, carbohydrate & uronic acids), rheological properties, and surface activity of Lallemantia royleana seeds mucilage (BSG) were determined. The results showed BSG contains 8.51% (w.b.) moisture, 8.24% (d.b.) ash, 2.71% (d.b.) protein, 75.87% (d.b.) carbohydrate and 20.33% (d.b.) uronic acids. Monosaccharide analysis revealed the presence of arabinose (37.88%), galactose (33.54%), rhamnose (18.44%), xylose (6.02%) and glucose (4.11%) in the BSG polysaccharide. Although BSG had similar molecular weight (1.294×10(6) Da) compared to most seed gums, the intrinsic viscosity (23.06 dL/g) and gyration radius (104.84 nm) were higher. The BSG exhibited a strong shear-thinning behavior (nrheological properties. Dynamic mechanical spectra demonstrated BSG is a typical of weak gel, which its rheological parameters were superior to those of many commercial gums. The FTIR spectra of the BSG polymer showed the presence of carboxyl groups, which may serve as binding sites for ions. BSG exhibited the ability to reduce the surface tension of water at concentrations lower than 0.75%.

  3. Value addition to lignocellulosics and biomass-derived sugars: An insight into solid acid-based catalytic methods

    Indian Academy of Sciences (India)

    Prasenjit Bhaumik; A K Deepa; Tanushree Kane; Paresh Laxmikant Dhepe

    2014-03-01

    For the synthesis of important platform chemicals such as sugars (xylose and arabinose) and furans (furfural and 5-hydroxymethylfurfural (HMF)) from carbohydrates (hemicellulose and fructose) solid acid catalysts are employed. Similarly, over solid acid catalysts, conversion of lignin into aromatic monomers is performed. It is observed that in the dehydration of fructose, because of higher hydrothermal stability, silicoaluminophosphate (SAPO) catalysts give better activity (78% HMF yield) compared with other solid acid catalysts (<63% HMF yield) at 175°C. Particularly, SAPO-44 catalyst can be reused at least 5 times with marginal decrease in the activity. Zeolite, HUSY (Si/Al = 15) is active in the conversion of isolated (pure) hemicellulose to produce 41% C5 sugars in water. The catalyst is also active in the selective conversion of hemicellulose from bagasse to yield 59% C5 sugars. It is possible to obtain high yields of furfural (54%) directly from bagasse if instead of water, water+toluene solvent system is used. Depolymerization of lignin using HUSY catalyst produced aromatic monomers with 60% yield at 250°C. A detailed catalyst characterization study is performed to understand the correlation between catalyst activity and morphology. To understand the effect of impurities present in the substrate over solid acid catalysts, metal-exchange study is carried out.

  4. Characterization and free radical scavenging activity of rapeseed meal polysaccharides WPS-1 and APS-2.

    Science.gov (United States)

    Zhu, Jianfei; Wu, Moucheng

    2009-02-11

    Two major polysaccharide fractions, WPS-1 and APS-2, were isolated from water-soluble and alkali-soluble extracts of Huaza No. 4 rapeseed meal with a stepwise procedure of D3520 macroporous adsorption resin column chromatography, ethanol precipitation, and DE-52 cellulose column chromatography. Physicochemical properties of the polysaccharides were determined by chemical methods, high -performance liquid chromatography (HPLC), gel permeation chromatography (GPC), and Fourier transform infrared spectrometry (FT-IR). The chemiluminescence (CL) method was used to investigate the free radical scavenging activity of the polysaccharide fractions. The polysaccharides were primarily polymers of arabinose, galactose, and glucose, associated with protein portions consisting of 13 different amino acids. The average molecular masses of WPS-1 and APS-2 were 7.20 x 10(5) and 1.61 x 10(5) Da, respectively. Compared with APS-2, WPS-1 was more effective at scavenging superoxide radical (O(2)(*-)) and hydroxyl radical (HO(*)), but less effective at scavenging hydrogen peroxide (H(2)O(2)). In decreasing order, the free radical scavenging activity of WPS-1 and APS-2 toward reactive oxygen species (ROS) was H(2)O(2) > HO(*) > O(2)(*-).

  5. Immunodiagnosis of Citrus leprosis virus C using a polyclonal antibody to an expressed putative coat protein.

    Science.gov (United States)

    Choudhary, Nandlal; Roy, Avijit; Guillermo, Leon M; Picton, D D; Wei, G; Nakhla, M K; Levy, L; Brlansky, R H

    2013-11-01

    Citrus leprosis virus C (CiLV-C), a causal agent for citrus leprosis disease, is present in South and Central America and is a threat for introduction into the U.S. citrus industry. A specific, inexpensive and reliable antibody based detection system is needed for the rapid identification of CiLV-C. The CiLV-C is very labile and has not been purified in sufficient amount for antibody production. The p29 gene of CiLV-C genome that codes for the putative coat protein (PCP) was codon optimized for expression in Escherichia coli and synthesized in vitro. The optimized gene was sub-cloned into the bacterial expression vector pDEST17 and transferred into E. coli BL21AI competent cells. The expression of PCP containing N-terminal His-tag was optimized by induction with l-arabinose. Induced cells were disrupted by sonication and expressed PCP was purified by affinity chromatography using Ni-NTA agarose. The purified expressed PCP was then used as an immunogen for injections into rabbits to produce polyclonal antibody (PAb). The PAb specific to the expressed PCP was identified using Western blotting. The antibody was successfully used to detect CiLV-C in the symptomatic CiLV-C infected tissues using double antibody sandwich-enzyme-linked-immunosorbent (DAS-ELISA), indirect ELISA and dot-blot immunoassay (DBIA) formats.

  6. Amino acids interference on the quantification of reducing sugars by the 3,5-dinitrosalicylic acid assay mislead carbohydrase activity measurements.

    Science.gov (United States)

    Teixeira, Ricardo Sposina Sobral; da Silva, Ayla Sant'Ana; Ferreira-Leitão, Viridiana Santana; da Silva Bon, Elba Pinto

    2012-12-01

    This study evaluated the interference of the amino acids tryptophan, cysteine, histidine, tyrosine, hydroxyproline, leucine, proline, serine, glycine, valine, glutamic acid, phenylalanine, and methionine on the measurement of reducing sugars using a phenol-free 3,5-dinitrosalicylic acid (DNS) reagent. It was found that in reaction mixtures containing 20mM of either tryptophan, cysteine, histidine, tyrosine, or hydroxyproline the measurement of 3.7 mM glucose was overestimated by 76%, 50%, 35%, 18%, and 10%, respectively. The amino acids valine, glutamic acid, and phenylalanine did not affect the DNS reaction, while methionine decreased the color development by 5%. The measurement of glucose, xylose, arabinose, and cellobiose at the 3.7-12.4 mM range in the presence of 20 mM cysteine resulted in an overestimated concentration of 34.8-50%. Enzymatic assays for measuring xylanolytic and filter paper activity (FPAse) were conducted in the presence of 20-60 mM cysteine, and compared to cysteine-free assays. In the presence of cysteine, the measured xylanase activity increased threefold and the FPAse activity increased twofold due to the overestimation of the reducing sugar concentrations in the assays. The interference from cysteine was reduced to a maximum of 8.6% when a DNS reagent containing phenol was used.

  7. Analysis of reducing carbohydrates by reductive tryptamine derivatization prior to micellar electrokinetic capillary chromatography.

    Science.gov (United States)

    Andersen, Keld E; Bjergegaard, Charlotte; Sørensen, Hilmer

    2003-12-03

    A micellar electrokinetic capillary chromatography method for determination of low molecular weight carbohydrates (dp 1-2) with an unbound carbonyl group as in aldoses or other reducing carbohydrates has been developed. Reductive amination of aldoses on the carbonyl group using tryptamine introduced a chromophor system to the carbohydrates enabling their sensitive UV detection at 220 nm and identification based on the indole group using diode array detection. Twelve carbohydrates including pentoses (d-ribose, l-arabinose, and d-xylose), hexoses (d-glucose, d-mannose, and d-galactose), deoxy sugars (l-rhamnose and l-fucose), uronic acids (d-glucuronic acid and d-galacturonic acid), and disaccharides (cellobiose and melibiose) are included in the study, using d-thyminose (2-deoxy-d-ribose) as the internal standard. Detection of all 12 carbohydrates is performed within 30 min. Linearity with correlation coefficients from 0.9864 to 0.9992 was found in the concentration range of 25-2500 micromol/L for all carbohydrates; the relative standard deviation on the migration times was between 0.27 and 0.80 min, and limits of quantification and limits of determination were in the picomole range.

  8. A Sensitive Derivatization Method for the Determination of the Sugar Composition after Pre-column Reductive Amination with 3-Amino-9-ethylcarbazole (AEC) by High-Performance Liquid Chromatography

    Institute of Scientific and Technical Information of China (English)

    ZHANG, Ying; HUANG, Lin-Juan; WANG, Zhong-Fu

    2007-01-01

    3-Amino-9-ethylcarbazole (AEC) was employed for monosaccharide derivatization. The derivatives can be analyzed by high-performance liquid chromatography (HPLC) with an ultraviolet detection (wavelength: 254 nm).Monosaccharides were quantitatively derivatized with 3-amino-9-ethylcarbazole (AEC) at 70 ℃ for 60 min. The method was linear for all samples over the concentration range tested (r>0.999), the precision was found to be satisfactory (R.S.D.<3%), and the recovery ratios were >98.62%. The stability analysis showed R.S.D. Was between 1.81%-3.16%. Detection limits for the samples (D-glucose, L-xylose, D-mannose, L-arabinose, and L-rhamnose)ranged from 0.06 to 1.97 ng/mL (S/N=3). Under the optimized derivatization and HPLC conditions, five monosaccharides were well separated using a narrow bore C18 column (250 mm× 4.6 mm) with 0.1 mol/L ammonium acetate containing 25% acetonitrile at a flow rate of 0.5 mL/min. As an application, the method has been successfully applied to the determination of monosaccharide compositions of three polysaccharides SPPA-1, SPPB-1 and SPPC- 1 of Spirulina platensis. This method also has potential application to oligosaccharide or glycan analyses.

  9. Antihyperlipidemic and hepatoprotective activities of residue polysaccharide from Cordyceps militaris SU-12.

    Science.gov (United States)

    Wang, Liqin; Xu, Nuo; Zhang, Jianjun; Zhao, Huajie; Lin, Lin; Jia, Shouhua; Jia, Le

    2015-10-20

    Cordyceps militaris has been artificially cultivated in China, and the great amounts of produced medium residue were discarded after the harvest. The aims of this work were to analyze the structure of the residue polysaccharide (RPS) of C. militaris SU-12, and to investigate the pharmacological effects of RPS on lipid metabolism and oxidative stress. RPS was composed of glucose, arabinose and mannose with a ratio of 62:1.6:1 by gas chromatography analysis, and the Mw (weight-average molecular weight), Mn (number-average molecular weight) and Mz (z-average molecular weight) of RPS were 2.86×10(3), 6.85×10(2), and 1.97×10(4)Da, respectively. The mice experiments demonstrated that RPS could reduce the levels of blood and liver lipid, and improve the glutamate pyruvate transaminase and antioxidant activity. The histopathological observations of mice livers indicated that RPS could attenuate liver cell injury. Results suggest that the RPS might be used as a potential antihyperlipidemic, hepatoprotective and antioxidant product.

  10. Evaluation of Carbohydrates in Natural and Cultured Cordyceps by Pressurized Liquid Extraction and Gas Chromatography Coupled with Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Jia Guan

    2010-06-01

    Full Text Available Free and polymeric carbohydrates in Cordyceps, a valued edible mushroom and well-known traditional Chinese medicine, were determined using stepwise pressurized liquid extraction (PLE extraction and GC-MS. Based on the optimized PLE conditions, acid hydrolysis and derivatization, ten monosaccharides, namely rhamnose, ribose, arabinose, xylose, mannose, glucose, galactose, mannitol, fructose and sorbose in 13 samples of natural and cultured Cordyceps were qualitatively and quantitatively analyzed and compared with myo-inositol hexaacetate as internal standard. The results showed that natural C. sinensis contained more than 7.99% free mannitol and a small amount of glucose, while its polysaccharides were usually composed of mannose, glucose and galactose with a molar ratio of 1.00:16.61~3.82:1.60~1.28. However, mannitol in cultured C. sinensis and cultured C. militaris were less than 5.83%, and free glucose was only detected in a few samples, while their polysaccharides were mainly composed of mannose, glucose and galactose with molar ratios of 1.00:3.01~1.09:3.30~1.05 and 1.00:2.86~1.28:1.07~0.78, respectively. Natural and cultured Cordyceps could be discriminated by hierarchical clustering analysis based on its free carbohydrate contents.

  11. Wood pulp as an immobilization matrix for the continuous production of isopropanol and butanol.

    Science.gov (United States)

    Survase, Shrikant A; van Heiningen, Adriaan; Granström, Tom

    2013-02-01

    The study was focused on developing a continuous method to produce an alcohol mixture suitable to be used as a gasoline supplement. The immobilized column reactor with wood pulp fibers was successfully used for the continuous production of butanol and isopropanol using Clostridium beijerinckii DSM 6423. A sugar mixture (glucose, mannose, galactose, arabinose and xylose) representing lignocellulose hydrolysate was used as a substrate for the production of solvents. The effect of dilution rate on solvent production was studied during continuous operation. The maximum total solvent concentration of 11.99 g/l was obtained at a dilution rate of 0.16 h(-1). The maximum solvent productivity (5.58 g/l h) was obtained at a dilution rate of 1.5 h(-1). The maximum solvent yield of 0.45 g/g from sugar mixture was observed at 0.25 h(-1). The system will be further used for the solvent production using wood hydrolysate as a substrate.

  12. Comparison of microwave oven and convection oven for acid hydrolysis of dietary fiber polysaccharides.

    Science.gov (United States)

    Li, B W

    1998-01-01

    Hydrolysis of dietary fiber polysaccharides (DFP) is an integral part of any enzymatic-chemical method for dietary fiber analysis. Residues obtained after enzyme treatments of fiber-containing foods are usually suspended in 12 M sulfuric acid and kept at or slightly above ambient temperature for at least 1 h, and then the mixtures are diluted with deionized water to a final concentration of 1 M or 2 M acid, followed by heating at 100 degrees C in a water bath or convection oven for 1 or 2 h. Under these hydrolytic conditions, some degradation of the released monosaccharides generally takes place over the duration of hydrolysis. We investigated the feasibility of using microwave energy as a heat source to reduce time and minimize degradation. Preliminary tests were done on the well-characterized soy polysaccharide Fibrim. With a microwave digestion system equipped with temperature and pressure monitors and control lines, optimum settings of power (5%, 75%), time (up to 3 min and 30 s), temperature (35 degrees-55 degrees C), and pressure (45-65 psi) were determined for different foods depending on the residue weight and volume of acid. Results were comparable for microwave oven and convection oven hydrolysis of DFP from 5 foods with good correlations for neutral sugar values; r2 = 0.997 for arabinose, 0.925 for galactose, 0.981 for glucose, 0.969 for mannose, and 0.990 for xylose.

  13. RAW264.7 Cell Activating Glucomannans Extracted from Rhizome of Polygonatum sibiricum

    Science.gov (United States)

    Yelithao, Khamphone; Surayot, Utoomporn; Lee, Ju Hun; You, SangGuan

    2016-01-01

    Water-soluble polysaccharides isolated from the rhizome of Polygonatum sibiricum and fractionated using ion-exchange chromatography were investigated to determine their structure and immunostimulating activity. Crude and fractions (F1 and F2) consisted of carbohydrates (85.1~88.3%) with proteins (4.51~11.9%) and uronic acid (1.79~7.47%), and included different levels of mannose (62.3~76.3%), glucose (15.2~20.3%), galactose (4.35~15.3%), and arabinose (4.00~7.65%). The crude contained two peaks with molecular weights (Mw) of 151×103 and 31.8×103, but F1 and F2 exhibited one major peak with Mw of 103×103 and 628×103, respectively. Little immunostimulatory activity was observed by the crude; however, F1 and F2 significantly activated RAW264.7 cells to release nitric oxide and various cytokines, suggesting they were potent immunostimulators. The backbone of the most immunostimulating fraction (F1) was (1→4)-manno- and (1→4)-gluco-pyranosyl residues with galactose and glucose attached to O-6 of manno-pyranoside. PMID:27752501

  14. An acetate-hydroxide gradient for the quantitation of the neutral sugar and uronic acid profile of pectins by HPAEC-PAD without postcolumn pH adjustment.

    Science.gov (United States)

    Nagel, Andreas; Sirisakulwat, Suparat; Carle, Reinhold; Neidhart, Sybille

    2014-03-05

    An HPAEC-PAD method was developed and validated to quantitate seven neutral sugars and two uronic acids of hydrolyzed pectic polysaccharides without postcolumn pH adjustment. Due to a short gradient phase minimizing the ion concentrations after equilibrating the CarboPac PA20 column with sodium acetate and hydroxide, subsequent isocratic separation of the neutral sugars was characterized by almost baseline resolution of rhamnose and arabinose (1.45 ± 0.15) and xylose and mannose (1.21 ± 0.02) at their maximal concentrations. Linearity was shown (R² = 0.9975-0.9998) for the relevant ranges (0.28-30.3 μmol L⁻¹); galacturonic acid, 1.7-128 μmol L⁻¹) above the limits of detection (30-81 nmol L⁻¹; galacturonic acid, 179 nmol L⁻¹) and ∼3.8 times higher limits of quantification. Conformity of the findings for four pectins after methanolysis plus hydrolysis in trifluoroacetic acid with those of reference procedures (total uronic acids, 95-102%; total neutral sugars, 97-105%) proved the accuracy.

  15. Detection of carbohydrates using a pre-column derivatization reagent 1-(4-isopropyl) phenyl-3-methyl-5-pyrazolone by high-performance liquid chromatography coupled with electrospray ionization mass spectrometry.

    Science.gov (United States)

    Zhang, Ping; Wang, Zhongfu; Xie, Mingming; Nie, Wanli; Huang, Linjuan

    2010-05-01

    A reagent, 1-(4-isopropyl) phenyl-3-methyl-5-pyrazolone (PPMP) has been synthesized and used for high-performance liquid chromatography/electrospray ionization mass spectrometry (HPLC/ESI-MS) determination of pre-column labeled carbohydrates. Monosaccharides have been quantitatively converted into mono-PPMP-labeled derivatives with 28% aqueous ammonia as a catalyst at 80 degrees C during 70 min. Mono-PPMP derivatives have been demonstrated to exhibit better chemical stability than bis-PMP ones. PPMP-labeled mixture of twelve monosaccharides (galactosamine, glucosamine, galacturonic acid, glucuronic acid, galactose, glucose/N-acetylgalactosamine, N-acetylglucosamine, xylose, arabinose, mannose, fucose, and rhamnose) has been well separated by a reverse-phase HPLC and detected by on-line ESI-MS method under optimized conditions. The data on characteristic fragment ions of the 13 PPMP-labeled monosaccharides with MS(2) data have been collected. The suggested method exhibits good linearity (correlation coefficients > 0.9975) between the peak areas and the concentration of monosaccharides in a broad concentration range and good reproducibility (RSD < 3.19%). The developed method has been successfully applied to analyze the monosaccharide composition of natural Spirulina polysaccharide SPPB-1.

  16. Effects of level of dietary intake and physical form of protein supplement on the digestibilities of different dietary carbohydrates between mouth and abomasum of young steers.

    Science.gov (United States)

    McAllan, A B; Smith, R H

    1983-09-01

    Steers fitted with simple rumen and abomasal cannulas were given isoenergetic diets of rolled barley and chopped straw, pelleted together with some tapioca alone (B) or with some tapioca replaced by coarse soyabean meal (M) or finely ground soyabean flour (F). The diets were given at two levels to support 0.5 (L) and 1.0 (H) kg/d live weight gain. Chromic oxide and PEG were given as digesta flow markers. Mouth to abomasum digestibilities of different dietary sugars at the low level of intake (LB) were 0.65, 0.68, 0.59, 0.56 and 0.94 for arabinose, galactose, xylose, cellulose-glucose and starch-glucose respectively. Corresponding values at the higher level of intake (HB) were 0.55, 0.66, 0.55, 0.44 and 0.93 respectively. Supplementation with either soya bean meal or flour had no significant effects on the mouth to abomasum of dietary carbohydrate digestibilities at either level of feeding.

  17. Impact of Residual Inducer on Titratable Expression Systems.

    Directory of Open Access Journals (Sweden)

    Taliman Afroz

    Full Text Available Inducible expression systems are widely employed for the titratable control of gene expression, yet molecules inadvertently present in the growth medium or synthesized by the host cells can alter the response profile of some of these systems. Here, we explored the quantitative impact of these residual inducers on the apparent response properties of inducible systems. Using a simple mathematical model, we found that the presence of residual inducer shrinks the apparent dynamic range and causes the apparent Hill coefficient to converge to one. We also found that activating systems were more sensitive than repressing systems to the presence of residual inducer and the response parameters were most heavily dependent on the original Hill coefficient. Experimental interrogation of common titratable systems based on an L-arabinose inducible promoter or a thiamine pyrophosphate-repressing riboswitch in Escherichia coli confirmed the predicted trends. We finally found that residual inducer had a distinct effect on "all-or-none" systems, which exhibited increased sensitivity to the added inducer until becoming fully induced. Our findings indicate that residual inducer or repressor alters the quantitative response properties of titratable systems, impacting their utility for scientific discovery and pathway engineering.

  18. Tamarind Seed Xyloglucans Promote Proliferation and Migration of Human Skin Cells through Internalization via Stimulation of Proproliferative Signal Transduction Pathways.

    Science.gov (United States)

    Nie, W; Deters, A M

    2013-01-01

    Xyloglucans (XGs) of Tamarindus indica L. Fabaceae are used as drug vehicles or as ingredients of cosmetics. Two xyloglucans were extracted from T. indica seed with cold water (TSw) and copper complex precipitation (TSc). Both were analyzed in regard to composition and influence on cell viability, proliferation, cell cycle progression, migration, MAPK phosphorylation, and gene expression of human skin keratinocytes (NHEK and HaCaT) and fibroblasts (NHDF) in vitro. TSw and TSc differed in molecular weight, rhamnose content, and ratios of xylose, arabinose, galactose, and glucose. Both XGs improved keratinocytes and fibroblast proliferation, promoted the cell cycle, and stimulated migration and intracellular enzyme activity of NHDF after endosomal uptake. Only TSw significantly enhanced HaCaT migration and extracellular enzyme activity of NHDF and HaCaT. TSw and TSc predominantly enhanced the phosphorylation of molecules that referred to Erk signaling in NHEK. In NHDF parts of the integrin signaling and SAPK/JNK pathway were affected. Independent of cell type TSw marginally regulated the expression of genes, which referred to membrane proteins, cytoskeleton, cytokine signaling, and ECM as well as to processes of metabolism and transcription. Results show that T. indica xyloglucans promote skin regeneration by a direct influence on cell proliferation and migration.

  19. Metabolic engineering for improved fermentation of pentoses by yeasts.

    Science.gov (United States)

    Jeffries, T W; Jin, Y-S

    2004-02-01

    The fermentation of xylose is essential for the bioconversion of lignocellulose to fuels and chemicals, but wild-type strains of Saccharomyces cerevisiae do not metabolize xylose, so researchers have engineered xylose metabolism in this yeast. Glucose transporters mediate xylose uptake, but no transporter specific for xylose has yet been identified. Over-expressing genes for aldose (xylose) reductase, xylitol dehydrogenase and moderate levels of xylulokinase enable xylose assimilation and fermentation, but a balanced supply of NAD(P) and NAD(P)H must be maintained to avoid xylitol production. Reducing production of NADPH by blocking the oxidative pentose phosphate cycle can reduce xylitol formation, but this occurs at the expense of xylose assimilation. Respiration is critical for growth on xylose by both native xylose-fermenting yeasts and recombinant S, cerevisiae. Anaerobic growth by recombinant mutants has been reported. Reducing the respiration capacity of xylose-metabolizing yeasts increases ethanol production. Recently, two routes for arabinose metabolism have been engineered in S. cerevisiae and adapted strains of Pichia stipitis have been shown to ferment hydrolysates with ethanol yields of 0.45 g g(-1) sugar consumed, so commercialization seems feasible for some applications.

  20. Computational approaches for the genetic and phenotypic characterization of a Saccharomyces cerevisiae wine yeast collection.

    Science.gov (United States)

    Franco-Duarte, R; Umek, L; Zupan, B; Schuller, D

    2009-12-01

    Within this study, we have used a set of computational techniques to relate the genotypes and phenotypes of natural populations of Saccharomyces cerevisiae, using allelic information from 11 microsatellite loci and results from 24 phenotypic tests. A group of 103 strains was obtained from a larger S. cerevisiae winemaking strain collection by clustering with self-organizing maps. These strains were further characterized regarding their allelic combinations for 11 microsatellites and analysed in phenotypic screens that included taxonomic criteria (carbon and nitrogen assimilation tests, growth at different temperatures) and tests with biotechnological relevance (ethanol resistance, H(2)S or aromatic precursors formation). Phenotypic variability was rather high and each strain showed a unique phenotypic profile. The results, expressed as optical density (A(640)) after 22 h of growth, were in agreement with taxonomic data, although with some exceptions, since few strains were capable of consuming arabinose and ribose to a small extent. Based on microsatellite allelic information, naïve Bayesian classifier correctly assigned (AUC = 0.81, p 0.75). Subgroups were found for strains with low ethanol resistance, growth at 30 degrees C and growth in media containing galactose, raffinose or urea. The results demonstrate that computational approaches can be used to establish genotype-phenotype relations and to make predictions about a strain's biotechnological potential.

  1. Synergistic degradation of arabinoxylan with alpha-L-arabinofuranosidase, xylanase and beta-xylosidase from soy sauce koji mold, Aspergillus oryzae, in high salt condition.

    Science.gov (United States)

    Hashimoto, Tadaaki; Nakata, Yoshiyuki

    2003-01-01

    This study addresses induction and some properties of alpha-L-arabinofuranosidase from a soy sauce koji mold, Aspergillus oryzae HL15, cultured on solid and liquid media. Alpha-L-arabinofuranosidase was induced by soybean polysaccharide and secreted into media on solid cultivation; the enzyme was associated with mycelium as a cell-wall-bound form in liquid cultivation. A major alpha-L-arabinofuranosidase, which was purified homogeneously on SDS-PAGE, showed highest activity in the presence of 10% of NaCl; also, somewhat higher activity was observed even in 25% NaCl than in the absence of NaCl. Arabinoxylan was synergistically degraded by xylanase, beta-xylosidase, and alpha-L-arabinofuranosidase from A. oryzae HL15 in the condition of imitative pH 5.0 and 15% NaCl concentration of the soy sauce moromi mash. These results suggest that arabinose and xylose, which are closely related to melanoidin formation, can be released by synergistic action of these enzymes in soy sauce moromi mash.

  2. Final Technical Report: Improvement of Zymomonas mobilis for Commercial Use in Corn-based Biorefineries

    Energy Technology Data Exchange (ETDEWEB)

    Hitz, William D.

    2010-12-07

    Between 2007 and 2010 DuPont conducted a program under DOE award DE-FC36-07GO17056 to develop and improve Zymomonas mobilis as an ethanologen for commercial use in biorefineries to produce cellulosic ethanol. This program followed upon an earlier DOE funded program in which DuPont, in collaboration with the National Renewable Energy Laboratory (NREL) had developed a Zymomonas strain in conjunction with the development of an integrated cellulosic ethanol process. In the current project, we sought to maximize the utility of Zymomonas by adding the pathway to allow fermentation of the minor sugar arabinose, improve the utilization of xylose, improve tolerance to process hydrolysate and reduce the cost of producing the ethanologen. We undertook four major work streams to address these tasks, employing a range of approaches including genetic engineering, adaptation, metabolite and pathway analysis and fermentation process development. Through this project, we have developed a series of strains with improved characteristics versus the starting strain, and demonstrated robust scalability to at least the 200L scale. By a combination of improved ethanol fermentation yield and titer as well as reduced seed train costs, we have been able to reduce the capital investment and minimum ethanol selling price (MESP) by approximately 8.5% and 11% respectively vs. our starting point. Furthermore, the new strains we have developed, coupled with the learnings of this program, provide a platform for further strain improvements and advancement of cellulosic ethanol technology.

  3. Comparative decomposition kinetics of neutral monosaccharides by microwave and induction heating treatments.

    Science.gov (United States)

    Tsubaki, Shuntaro; Oono, Kiriyo; Onda, Ayumu; Yanagisawa, Kazumichi; Azuma, Jun-ichi

    2013-06-28

    The stabilities of five neutral monosaccharides (glucose, galactose, mannose, arabinose, and xylose) were kinetically compared after the molecules were submitted to microwave heating (internal heating) and induction heating (external heating) under completely identical thermal histories by employing PID (proportional, integral, and derivative) temperature controlled ovens and homogeneous mixing. By heating in water at 200°C, the rate constants for the decomposition reactions varied from 2.13×10(-4) to 3.87×10(-4)s(-1) for microwave heating; however, the values increased by 1.1- to 1.5-fold for induction heating. Similarly, in a dilute (0.8%) sulfuric acid solution, the decomposition rate constants varied from 0.61×10(-3) to 2.00×10(-3)s(-1) for microwave heating; however, the values increased by 1.5- to 2.2-fold for induction heating. The results show that microwave heating imparts greater stability to neutral monosaccharides than does induction heating. The undesirable decomposition of monosaccharides at the surface boundary of reactor walls may have increased the probability of monosaccharide decomposition during induction heating.

  4. Characterization and degradation of pectin derived from Budimka apple

    Directory of Open Access Journals (Sweden)

    MILOS V. NIKOLIC

    2008-02-01

    Full Text Available The characterization of apple pectin and its oligogalacturonic fractions derived from the autochthones apple variety Budimka, characteristic for central Serbia, is described in this paper. After extraction, the apple pectin was subjected to controlled enzymatic hydrolysis by polygalacturonase (PG and pectin lyase (PL from Aspergillus niger and then fractionated by ion-exchange column chromatography on Dowex 1X-8 (200–400 mesh. Saturated oligogalacturonic acids, obtained by controlled hydrolysis with PG, were efficiently separated by elution with a gradient of Na acetate buffer (pH 6.0, while unsaturated oligogalacturonic acids, obtained by controlled hydrolysis with PL, were separated on the same resin, using a gradient of Na formate buffer (pH 4.7 as the eluent. The yields of the fractions with the particular degree of polymerization (DP were also determined. The total content of neutral saccharides in the original Budimka apple pectin was detected by HPLC analysis of the 4-nitrobenzoyl derivatives of the sugar, and amounted to 5.31 %. Among the neutral saccharides, contents of galactose, glucose, rhamnose, arabinose, xylose and mannose were detected.

  5. Primary characterization and evaluation of anti ulcerogenic activity of an aqueous extract from callus culture of Cereus peruvianus Mill. (Cactaceae).

    Science.gov (United States)

    Jayme, Milena O; Ames, Franciele Q; Bersani-Amado, Ciomar A; Machado, Maria de Fatima P S; Mangolin, Claudete A; Goncalves, Regina A C; de Oliveira, Arildo J B

    2015-01-01

    In the current study we reported cultivation, extraction procedure, analysis and preliminary characterization of the aqueous extract from Cereus peruvianus callus culture and evaluated its anti ulcerogenic activity in vivo models of experimental ulcers in Wistar rats. The obtained aqueous extract from callus (AC) was dialyzed and subjected to freeze-thaw process, providing a possible polysaccharide. The carbohydrate and protein contents of the aqueous extract were estimated at 53.4% and 0.66%, respectively, composed primarily of galactose, arabinose and galacturonic acid, with minor amounts of glucose. This appeared heterogeneous when analyzed by high-performance size-exclusion chromatography and a multiangle laser light scattering detector (HPSEC-MALLS). The AC was found to be significantly effective against ethanol-induced lesions but was ineffective against indomethacin-induced lesions. The callus culture of C. peruvianus is an alternative source for the synthesis of substances originally produced by plants. The calluses grown indefinitely in vitro under controlled conditions are stable tissues, and the aqueous extract from calluses may be used instead of fully developed plants using the protocols described in this study.

  6. A study on the interaction of rhodamine B with methylthioadenosine phosphorylase protein sourced from an Antarctic soil metagenomic library.

    Science.gov (United States)

    Bartasun, Paulina; Cieśliński, Hubert; Bujacz, Anna; Wierzbicka-Woś, Anna; Kur, Józef

    2013-01-01

    The presented study examines the phenomenon of the fluorescence under UV light excitation (312 nm) of E. coli cells expressing a novel metagenomic-derived putative methylthioadenosine phosphorylase gene, called rsfp, grown on LB agar supplemented with a fluorescent dye rhodamine B. For this purpose, an rsfp gene was cloned and expressed in an LMG194 E. coli strain using an arabinose promoter. The resulting RSFP protein was purified and its UV-VIS absorbance spectrum and emission spectrum were assayed. Simultaneously, the same spectroscopic studies were carried out for rhodamine B in the absence or presence of RSFP protein or native E. coli proteins, respectively. The results of the spectroscopic studies suggested that the fluorescence of E. coli cells expressing rsfp gene under UV illumination is due to the interaction of rhodamine B molecules with the RSFP protein. Finally, this interaction was proved by a crystallographic study and then by site-directed mutagenesis of rsfp gene sequence. The crystal structures of RSFP apo form (1.98 Å) and complex RSFP/RB (1.90 Å) show a trimer of RSFP molecules located on the crystallographic six fold screw axis. The RSFP complex with rhodamine B revealed the binding site for RB, in the pocket located on the interface between symmetry related monomers.

  7. A study on the interaction of rhodamine B with methylthioadenosine phosphorylase protein sourced from an Antarctic soil metagenomic library.

    Directory of Open Access Journals (Sweden)

    Paulina Bartasun

    Full Text Available The presented study examines the phenomenon of the fluorescence under UV light excitation (312 nm of E. coli cells expressing a novel metagenomic-derived putative methylthioadenosine phosphorylase gene, called rsfp, grown on LB agar supplemented with a fluorescent dye rhodamine B. For this purpose, an rsfp gene was cloned and expressed in an LMG194 E. coli strain using an arabinose promoter. The resulting RSFP protein was purified and its UV-VIS absorbance spectrum and emission spectrum were assayed. Simultaneously, the same spectroscopic studies were carried out for rhodamine B in the absence or presence of RSFP protein or native E. coli proteins, respectively. The results of the spectroscopic studies suggested that the fluorescence of E. coli cells expressing rsfp gene under UV illumination is due to the interaction of rhodamine B molecules with the RSFP protein. Finally, this interaction was proved by a crystallographic study and then by site-directed mutagenesis of rsfp gene sequence. The crystal structures of RSFP apo form (1.98 Å and complex RSFP/RB (1.90 Å show a trimer of RSFP molecules located on the crystallographic six fold screw axis. The RSFP complex with rhodamine B revealed the binding site for RB, in the pocket located on the interface between symmetry related monomers.

  8. Identification of Cultured and Natural Astragalus Root Based on Monosaccharide Mapping

    Directory of Open Access Journals (Sweden)

    Ke Li

    2015-09-01

    Full Text Available As the main substances responsible for immunomodulatory activity, saccharides can be used as quality indicators for Astragalus root (RA. Saccharide content is commonly determined by ultraviolet spectroscopy, which lacks species specificity and has not been applied in the Chinese Pharmacopoeia. Monosaccharide mapping based on trifluoroacetic acid (TFA hydrolysis can be used for quantitative analysis of saccharide compositions. In addition, species specificity can be evaluated by analysis of the mapping characteristics. In this study, monosaccharide mapping of soluble saccharides in the cytoplasm and polysaccharides in the cell wall of 24 batches of RA samples with different growth patterns were obtained based on TFA hydrolysis followed by gas chromatography-mass spectrometry. Results indicated that the mapping and the molar ratios of saccharide compositions of the cultured and natural RA samples were different for both cytoplasm and cell wall. For example, the molar ratio of mannose and arabinose was more than 3.5:1 in cytoplasm in cultured RA, whereas the ratio was less than 3.5:1 in natural RA. This research not only lays a foundation for screening indicators for RA, but also provided new ways of evaluating the quality of Chinese medicinal materials in which saccharides are the main bioactive substances.

  9. Selective separation of protein and saccharides by ionic liquids aqueous two-phase systems

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In the present work,it was found that aqueous solution of a hydrophilic ionic liquid (IL),1-butyl-3-methylimidazolium dicyanamide ([C4mim][N(CN)2]),could be separated into an aqueous two-phase system (ATPS) by inorganic salts such as K2HPO4 and K3PO4.The top phase is IL-rich,while the bottom phase is phosphate-rich.It was shown that 82.7%-100% bovine serum albumin (BSA) could be enriched into the top phase and almost quantitative saccharides (arabinose,glucose,sucrose,raffinose or dextran) were preferentially extracted into the bottom phase in a single-step extraction by [C4mim][N(CN)2] + K2HPO4 ATPS.The extraction efficiency of BSA from the aqueous saccharide solutions was influenced by the molecular structure of saccharides.The conductivity,dynamic light scattering (DLS) and transmission electron microscopy (TEM) were combined to investigate the microstructure of the IL-rich top phase and the possible mechanism for the selective separation.It is suggested that the formation of the IL aggregate and the IL aggregate-BSA complex plays a significant role in the separation of BSA from aqueous saccharide solutions.This is the first example for the selective separation by ILs-based ATPSs.It is expected that these findings would have potential applications in bio-analysis,separation,and IL recycle.

  10. Monosaccharide-NAIM Derivatives for D-, L-Configurational Analysis

    Directory of Open Access Journals (Sweden)

    Chunchi Lin

    2011-01-01

    Full Text Available The D-, L-enantiomeric pairs of common monosaccharides (xylose, ribose, rhamnose, arabinose, fucose, glucose, mannose, galactose, N-acetylgalactosamine, glucuronic acid and galacturonic acid were derivatized with 2,3-naphthalenediamine to form the corresponding D-, L-aldo-NAIM derivatives. A simple and facile capillary electrophoretic method was established for sugar composition analysis by simultaneously determining the migration times of these aldo-NAIMs using borate buffer at high pH (100 mM, pH 9.0. The methodology is also applicable to sialic acid (ketose monosaccharides. The quantitation level of the proposed method was in the 10~500 ppm range and the LOD was 1 ppm. The enantioseparation of D, L pairs of aldo-NAIMs were also achieved by using modified sulfated-a-cyclodextrin as the chiral selector in phosphate buffer (300 mM, pH 3.0. In addition, the combination by reductive amination of amino-aldo-NAIM agent and D-, L-enantiomeric pairs of monosaccharides formed a diastereomeric pair for saccharide configuration analysis. Aldo-NAIM derivatives are thus shown to be rapid and efficient agents for analyzing saccharide compositions and configurations with good linearity and short analysis times via capillary electrophoresis.

  11. Metabolic engineering for improved microbial pentose fermentation.

    Science.gov (United States)

    Fernandes, Sara; Murray, Patrick

    2010-01-01

    Global concern over the depletion of fossil fuel reserves, and the detrimental impact that combustion of these materials has on the environment, is focusing attention on initiatives to create sustainable approaches for the production and use of biofuels from various biomass substrates. The development of a low-cost, safe and eco-friendly process for the utilization of renewable resources to generate value-added products with biotechnological potential as well as robust microorganisms capable of efficient fermentation of all types of sugars are essential to underpin the economic production of biofuels from biomass feedstocks. Saccharomyces cerevisiae, the most established fermentation yeast used in large scale bioconversion strategies, does not however metabolise the pentose sugars, xylose and arabinose and bioengineering is required for introduction of efficient pentose metabolic pathways and pentose sugar transport proteins for bioconversion of these substrates. Our approach provided a basis for future experiments that may ultimately lead to the development of industrial S. cerevisiae strains engineered to express pentose metabolising proteins from thermophilic fungi living on decaying plant material and here we expand our original article and discuss the strategies implemented to improve pentose fermentation.

  12. Karakteristik dan Patogenisitas Streptococcus Agalactiae Tipe ?-hemolitik dan Non-hemolitik pada Ikan Nila

    Directory of Open Access Journals (Sweden)

    Esti Handayani Hardi

    2012-11-01

    Full Text Available Streptococcus agalactiae was isolated from cultured Nile tilapia (Oreochromis niloticus in Cirata gulfand Klaten. The isolates were Gram positive cocci, oxidative fermentative positive, motility, and catalasenegative, grown on media containing NaCl 6.5%, ?-haemolytic and non-haemolytic. Two types of S. agalactiae(?-haemolytic and non-haemolytic are different from their variety of sugars fermentation. Strains ?-haemolytic can ferment more sugars, including arabinose, sorbitol, lactose, and trehalose. Experimentalinfectivity trials on Nile tilapia (size 15 g, non-haemolytic type showed more virulent. This type causedfaster mortality, more severe behavior changes, and pathology changes than â-haemolytic type. NonhemoliticS. agalactiae caused 48% mortality 6-24 hours after injection, whereas â-haemolitic type caused17% mortality which it occured in 48 hours after injection (mortality of fish control 2,22%. Behaviordisease signs caused by non-haemolitic S. agalactiae started to happen 6 hours after injection whereas 12hours in ?-haemolytic type infection. Histopatological changes were observed on fish eye, spleen, andbrain. Hyperaemia, hyperthrophi, degeneration, and necrosis were also found on infected fish. Thisresearch was concluded that non-haemolytic of S. agalactiae was more virulent than ?-haemolytic.

  13. Inositol Metabolism in Plants. III. Conversion of Myo-inositol-2-H to Cell Wall Polysaccharides in Sycamore (Acer pseudoplatanus L.) Cell Culture.

    Science.gov (United States)

    Roberts, R M; Loewus, F

    1966-11-01

    Prolonged growth of cell cultures of sycamore (Acer pseudoplatanus L.) on agar medium containing myo-inositol-2-(3)H resulted in incorporation of label predominately into uronosyl and pentosyl units of cell wall polysaccharides. Procedures normally used to distinguish between pectic substance and hemicellulose yielded carbohydrate-rich fractions with solubility characteristics ranging from pectic substance to hemicellulose yet the uronic acid and pentose composition of these fractions was decidedly pectic. Galacturonic acid was the only uronic acid present in each fraction. Subfractionation of alkali-soluble (hemicellulosic) polysaccharide by neutralization followed by ethanol precipitation gave 3 fractions, a water-insoluble, an ethanol-insoluble, and an ethanol-soluble fraction, each progressively poorer in galacturonic acid units and progressively richer in arabinose units; all relatively poor in xylose units.Apparently, processes involved in biosynthesis of primary cell wall continued to produce pectic substance during cell enlargement while processes leading to biosynthesis of typically secondary cell wall polysaccharide such as 4-0-methyl glucuronoxylan were not activated.

  14. Optimization of Brewery's spent grain dilute-acid hydrolysis for the production of pentose-rich culture media.

    Science.gov (United States)

    Carvalheiro, Florbela; Duarte, Luís C; Medeiros, Raquel; Gírio, Francisco M

    2004-01-01

    Dilute-acid hydrolysis of brewery's spent grain to obtain a pentose-rich fermentable hydrolysate was investigated. The influence of operational conditions on polysaccharide hydrolysis was assessed by the combined severity parameter (CS) in the range of 1.39-3.06. When the CS increased, the pentose sugars concentration increased to a maximum at a CS of 1.94, whereas the maximum glucose concentration was obtained for a CS of 2.65. The concentrations of furfural, hydroxymethylfurfural (HMF), as well as formic and levulinic acids and total phenolic compounds increased with severity. Optimum hydrolysis conditions were found at a CS of 1.94 with >95% of feedstock pentose sugars recovered in the monomeric form, together with a low content of furfural, HMF, acetic and formic acids, and total phenolic compounds. This hydrolysate containing glucose, xylose, and arabinose (ratio 10:67:32) was further supplemented with inorganic salts and vitamins and readily fermented by the yeast Debaryomyces hansenii CCMI 941 without any previous detoxification stage. The yeast was able to consume all sugars, furfural, HMF, and acetic acid with high biomass yield, 0.68 C-mol/C-mol, and productivity, 0.92 g/(L.h). Detoxification with activated charcoal resulted in a similar biomass yield and a slight increase in the volumetric productivity (11%).

  15. Enzymatic saccharification and fermentation of paper and pulp industry effluent for biohydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Lakshmidevi, Rajendran; Muthukumar, Karuppan [Department of Chemical Engineering, Alagappa College of Technology Campus, Anna University Chennai, Chennai 600 025 (India)

    2010-04-15

    Paper and pulp industry effluent was enzymatically hydrolysed using crude cellulase enzyme (0.8-2.2FPU/ml) obtained from Trichoderma reesei and from the hydrolysate biohydrogen was produced using Enterobacter aerogenes. The influence of temperature and incubation time on enzyme production was studied. The optimum temperature for the growth of T. reesei was found to be around 29 C. The enzyme activity of 2.5 FPU/ml was found to produce about 22 g/l of total sugars consisting mainly of glucose, xylose and arabinose. Relevant kinetic parameters with respect to sugars production were estimated using two fraction model. The enzymatic hydrolysate was used for the biohydrogen production using E. aerogenes. The growth data obtained for E. aerogenes were fitted well with Monod and Logistic equations. The maximum hydrogen yield of 2.03 mol H{sub 2}/mol sugar and specific hydrogen production rate of 225 mmol of H{sub 2}/g cell/h were obtained with an initial concentration of 22 g/l of total sugars. The colour and COD of effluent was also decreased significantly during the production of hydrogen. The results showed that the paper and pulp industry effluent can be used as a substrate for biohydrogen production. (author)

  16. Upgrading of biorenewables to high energy density fuels

    Energy Technology Data Exchange (ETDEWEB)

    Gordon, John C [Los Alamos National Laboratory; Batista, Enrique R [Los Alamos National Laboratory; Chen, Weizhong [Los Alamos National Laboratory; Currier, Robert P [Los Alamos National Laboratory; Dirmyer, Matthew R [Los Alamos National Laboratory; John, Kevin D [Los Alamos National Laboratory; Kim, Jin K [Los Alamos National Laboratory; Keith, Jason [Los Alamos National Laboratory; Martin, Richard L [Los Alamos National Laboratory; Pierpont, Aaron W [Los Alamos National Laboratory; Silks Ill, L. A. " " Pete [Los Alamos National Laboratory; Smythe, Mathan C [Los Alamos National Laboratory; Sutton, Andrew D [Los Alamos National Laboratory; Taw, Felicia L [Los Alamos National Laboratory; Trovitch, Ryan J [Los Alamos National Laboratory; Vasudevan, Kalyan V [Los Alamos National Laboratory; Waidmann, Christopher R [Los Alamos National Laboratory; Wu, Ruilian [Los Alamos National Laboratory; Baker, R. Thomas [UNIV OF OTTAWWA; Schlaf, Marcel [UNIV OF GUELPH

    2010-12-07

    According to a recent report, lignocellulose is the most abundant renewable biological resource on earth, with an annual production of {approx} 200 x 10{sup 9} tons. Conversion of lignocellulosics derived from wood, agricultural wastes, and woody grasses into liquid fuels and value-added chemical feedstocks is an active area of research that has seen an explosion of effort due to the need to replace petroleum based sources. The carbohydrates D-glucose (C{sub 6}), L-arabinose (C{sub 5}), and D-xylose (C{sub 5}) are readily obtained from the hydrolysis of lignocellulose and constitute the most abundant renewable organic carbon source on the planet. Because they are naturally produced on such a large scale, these sugars have the greatest potential to displace petrochemical derived transportation fuel. Recent efforts in our laboratories aimed towards the production of high energy density transportation fuels from carbohydrates have been structured around the parameters of selective carbohydrate carbon chain extension chemistries, low reaction temperatures, and the desired use of water or neat substrate as the solvent. Some of our efforts in this regard will be presented.

  17. Optimisation of pressurised water extraction of polysaccharides from blackcurrant and its antioxidant activity.

    Science.gov (United States)

    Xu, Yaqin; Cai, Fei; Yu, Zeyuan; Zhang, Ling; Li, Xingguo; Yang, Yu; Liu, Gaijie

    2016-03-01

    Pressurised water extraction (PWE) of polysaccharides from blackcurrant fruits was investigated using a response surface methodology (RSM). The optimal conditions for PWE were: time 51min, pressure 1.6MPa, and temperature 52°C. Under these conditions, the experimental yield of Ribes nigrum L. polysaccharides (RNLP) was 11.68±0.12%, which closely agreed with the predicted value (11.77%). After preliminary purification with D4006 macroporous resin, RNLP I was obtained and its chemical characterisation was undertaken by GC, HPLC, and IR spectroscopy. RNLP I was composed of rhamnose, arabinose, xylose, mannose, galactose, and glucose with a molar ratio of 2.89:14.82:1.02:1.00:2.53:6.39 and its molecular weight was 1.49×10(4)kDa. The antioxidant activity of RNLP I was evaluated by free radical scavenging assays and a reducing power assay in vitro. RNLP I showed strong DPPH and superoxide radical scavenging activities and reducing power.

  18. Production of arabitol by yeasts: current status and future prospects.

    Science.gov (United States)

    Kordowska-Wiater, M

    2015-08-01

    Arabitol belongs to the pentitol family and is used in the food industry as a sweetener and in the production of human therapeutics as an anticariogenic agent and an adipose tissue reducer. It can also be utilized as a substrate for chemical products such as arabinoic and xylonic acids, propylene, ethylene glycol, xylitol and others. It is included on the list of 12 building block C3-C6 compounds, designated for further biotechnological research. This polyol can be produced by yeasts in the processes of bioconversion or biotransformation of waste materials from agriculture, the forest industry (l-arabinose, glucose) and the biodiesel industry (glycerol). The present review discusses research on native yeasts from the genera Candida, Pichia, Debaryomyces and Zygosaccharomyces as well as genetically modified strains of Saccharomyces cerevisiae which are able to utilize biomass hydrolysates to effectively produce L- or D-arabitol. The metabolic pathways of these yeasts leading from sugars and glycerol to arabitol are presented. Although the number of reports concerning microbial production of arabitol is rather limited, the research on this topic has been growing for the last several years, with researchers looking for new micro-organisms, substrates and technologies.

  19. [Isolation and chemical characterization of type R lipopolysaccharides of a hypovirulent strain of Yersinia pestis].

    Science.gov (United States)

    Minka, S; Bruneteau, M

    1998-05-01

    The lipopolysaccharides LPS I and LPS II, isolated from the hypovirulent EV40 strain of Yersinia pestis, are composed only of type R lipopolysaccharides. This type consists of two forms a and b, depending on their solubility pattern in a solvent mixture containing varying proportions of chloroform, methanol, hexane, and hydrochloric acid. LPS I consists of one subtype, RIb, while LPS II consists of two subtypes, RIIa and RIIb. Analysis by gel electrophoresis shows that the mass of these lipopolysaccharide forms are in the vicinity of 2000-3000 Da. The RIb and RIIb subtypes, which are found in the majority of lipopolysaccharide I and II fractions, are composed of ketoses and amines that are similar to those occurring in LPS I and LPS II. In contrast, the two subtypes RIIa and RIIb are different both in terms of the composition of lipid A and the extent of its substitution. Certain fractions of RIIa contain only lipid A and 3-deoxy-D-manno-octulosonic acid (KDO), while other fractions of RIIb possess a lipid A, which is not substituted by arabinose. The whole set of these R-type lipopolysaccharide forms are excellent models for the study of the role of the primary structure of the polysaccharide region, and for the effect of lipid A substitution on the biological activity of bacterial lipopolysaccharides.

  20. ENTRAPMENT OF FLUORESCENT E. COLI CELLS IN ALGINATE GEL

    Directory of Open Access Journals (Sweden)

    T. VINTILA

    2013-07-01

    Full Text Available By this experiment we will demonstrate the possibility to obtain genetically modified microbial strains that can be used as markers in different studies. The trait transferred in this study is the fluorescence in UV light expressed by a gene isolated from jellyfish. This gene was insered into a plasmid carrying ampiciline resistance and in the operon for arabinose fermentation. The plasmid was called pGLO. E coli HB101 K-12, ampicillin resistant colonies has been obtained. The colonies on the LB/amp/ara plate fluoresce green under UV light and the transformed colonies can grow on ampicillin. Transformation efficiency = 362 transformed colonies/ μg DNA. The cells where immobilized by entrapment in alginate gel to study the phenomenon involved in cells immobilization. After immobilization in alginate gel, 5x104 cells of E. coli pGLO / capsule and 1,4 x 105 cells of E. coli HB101/capsule has been found. Fluorescent microscopy revealed the presence of pGLO carrying cells into the capsules. After cultivation of alginate capsules containing E. coli in LB broth, and fluorescent microscopy of the capsule sections, several observations of the phenomenon involved in continuous fermentation using biocatalysts in has been made. These cells grow and migrate to the cortical part of the matrix where they are immobilized.