Identification of Important Amino Acids in Gal2p for Improving the L-arabinose Transport and Metabolism in Saccharomyces cerevisiae

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Chengqiang Wang

2017-07-01

Full Text Available Efficient and cost-effective bioethanol production from lignocellulosic materials requires co-fermentation of the main hydrolyzed sugars, including glucose, xylose, and L-arabinose. Saccharomyces cerevisiae is a glucose-fermenting yeast that is traditionally used for ethanol production. Fermentation of L-arabinose is also possible after metabolic engineering. Transport into the cell is the first and rate-limiting step for L-arabinose metabolism. The galactose permease, Gal2p, is a non-specific, endogenous monosaccharide transporter that has been shown to transport L-arabinose. However, Gal2p-mediated transport of L-arabinose occurs at a low efficiency. In this study, homologous modeling and L-arabinose docking were used to predict amino acids in Gal2p that are crucial for L-arabinose transport. Nine amino acid residues in Gal2p were identified and were the focus for site-directed mutagenesis. In the Gal2p transport-deficient chassis cells, the capacity for L-arabinose transport of the different Gal2p mutants was compared by testing growth rates using L-arabinose as the sole carbon source. Almost all the tested mutations affected L-arabinose transport capacity. Among them, F85 is a unique site. The F85S, F85G, F85C, and F85T point mutations significantly increased L-arabinose transport activities, while, the F85E and F85R mutations decreased L-arabinose transport activities compared to the Gal2p-expressing wild-type strain. These results verified F85 as a key residue in L-arabinose transport. The F85S mutation, having the most significant effect, elevated the exponential growth rate by 40%. The F85S mutation also improved xylose transport efficiency and weakened the glucose transport preference. Overall, enhancing the L-arabinose transport capacity further improved the L-arabinose metabolism of engineered S. cerevisiae.

Effects of L-arabinose efflux on λ Red recombination-mediated gene knockout in multiple-antimicrobial-resistant Salmonella enterica serovar Choleraesuis.

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Liao, Shi-Wei; Lee, Jen-Jie; Ptak, Christopher P; Wu, Ying-Chen; Hsuan, Shih-Ling; Kuo, Chih-Jung; Chen, Ter-Hsin

2018-03-01

In this study, six swine-derived multiple-antimicrobial-resistant (MAR) strains of Salmonella Choleraesuis (S. Choleraesuis) were demonstrated to possess higher efflux pump activity than the wild-type (WT). L-Arabinose, a common inducer for gene expression, modulated S. Choleraesuis efflux pump activity in a dose-dependent manner. At low L-arabinose concentrations, increasing L-arabinose led to a corresponding increase in fluorophore efflux, while at higher L-arabinose concentrations, increasing L-arabinose decreased fluorophore efflux activity. The WT S. Choleraesuis that lacks TolC (ΔtolC), an efflux protein associated with bacterial antibiotic resistance and virulence, was demonstrated to possess a significantly reduced ability to extrude L-arabinose. Further, due to the rapid export of L-arabinose, an efficient method for recombination-mediated gene knockout, the L-arabinose-inducible bacteriophage λ Red recombinase system, has a reduced recombination frequency (~ 12.5%) in clinically isolated MAR Salmonella strains. An increased recombination frequency (up to 60%) can be achieved using a higher concentration of L-arabinose (fivefold) for genetic manipulation and functional analysis for MAR Salmonella using the λ Red system. The study suggests that L-arabinose serves not only as an inducer of the TolC-dependent efflux system but also acts as a competitive substrate of the efflux system. In addition, understanding the TolC-dependent efflux of L-arabinose should facilitate the optimization of L-arabinose induction in strains with high efflux activity.

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

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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.

The secreted L-arabinose isomerase displays anti-hyperglycemic effects in mice.

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Rhimi, Moez; Bermudez-Humaran, Luis G; Huang, Yuan; Boudebbouze, Samira; Gaci, Nadia; Garnier, Alexandrine; Gratadoux, Jean-Jacques; Mkaouar, Héla; Langella, Philippe; Maguin, Emmanuelle

2015-12-21

The L-arabinose isomerase is an intracellular enzyme which converts L-arabinose into L-ribulose in living systems and D-galactose into D-tagatose in industrial processes and at industrial scales. D-tagatose is a natural ketohexose with potential uses in pharmaceutical and food industries. The D-galactose isomerization reaction is thermodynamically equilibrated, and leads to secondary subproducts at high pH. Therefore, an attractive L-arabinose isomerase should be thermoactive and acidotolerant with high catalytic efficiency. While many reports focused on the set out of a low cost process for the industrial production of D-tagatose, these procedures remain costly. When compared to intracellular enzymes, the production of extracellular ones constitutes an interesting strategy to increase the suitability of the biocatalysts. The L-arabinose isomerase (L-AI) from Lactobacillus sakei was expressed in Lactococcus lactis in fusion with the signal peptide of usp45 (SP(Usp45)). The L-AI protein and activity were detected only in the supernatant of the induced cultures of the recombinant L. lactis demonstrating the secretion in the medium of the intracellular L. sakei L-AI in an active form. Moreover, we showed an improvement in the enzyme secretion using either (1) L. lactis strains deficient for their two major proteases, ClpP and HtrA, or (2) an enhancer of protein secretion in L. lactis fused to the recombinant L-AI with the SP(Usp45). Th L-AI enzyme secreted by the recombinant L. lactis strains or produced intracellularly in E. coli, showed the same functional properties than the native enzyme. Furthermore, when mice are fed with the L. lactis strain secreting the L-AI and galactose, tagatose was produced in vivo and reduced the glycemia index. We report for the first time the secretion of the intracellular L-arabinose isomerase in the supernatant of food grade L. lactis cultures with hardly display other secreted proteins. The secreted L-AI originated from the food

Structure of the effector-binding domain of the arabinose repressor AraR from Bacillus subtilis

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Procházková, Kateřina; Čermáková, Kateřina [Academy of Sciences of the Czech Republic, Flemingovo nam. 2, Prague 6 (Czech Republic); Pachl, Petr; Sieglová, Irena [Academy of Sciences of the Czech Republic, Flemingovo nam. 2, Prague 6 (Czech Republic); Academy of Sciences of the Czech Republic, Videnska 1083, Prague 4 (Czech Republic); Fábry, Milan [Academy of Sciences of the Czech Republic, Videnska 1083, Prague 4 (Czech Republic); Otwinowski, Zbyszek [UT Southwestern Medical Center, Dallas, Texas (United States); Řezáčová, Pavlína, E-mail: rezacova@uochb.cas.cz [Academy of Sciences of the Czech Republic, Flemingovo nam. 2, Prague 6 (Czech Republic); Academy of Sciences of the Czech Republic, Videnska 1083, Prague 4 (Czech Republic)

2012-02-01

The crystal structure of the effector-binding domain of the transcriptional repressor AraR from B. subtilis in complex with the effector molecule (l-arabinose) was determined at 2.2 Å resolution. A detailed analysis of the crystal identified a dimer organization that is distinctive from that of other members of the GalR/LacI family. In Bacillus subtilis, the arabinose repressor AraR negatively controls the expression of genes in the metabolic pathway of arabinose-containing polysaccharides. The protein is composed of two domains of different phylogenetic origin and function: an N-terminal DNA-binding domain belonging to the GntR family and a C-terminal effector-binding domain that shows similarity to members of the GalR/LacI family. The crystal structure of the C-terminal effector-binding domain of AraR in complex with the effector l-arabinose has been determined at 2.2 Å resolution. The l-arabinose binding affinity was characterized by isothermal titration calorimetry and differential scanning fluorimetry; the K{sub d} value was 8.4 ± 0.4 µM. The effect of l-arabinose on the protein oligomeric state was investigated in solution and detailed analysis of the crystal identified a dimer organization which is distinctive from that of other members of the GalR/LacI family.

Quantification of Arabinose content and batter volume in elite black gram mutants induced by gamma rays and electron beam

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Vanniarajan, C.; Sri Subalakhshmi, V.K.I.; Se Shamyugtha; Rajeswaran, G.; Monica, R.; Veni, K.

2017-01-01

Black gram (Vignamungo (L) Hepper) is one among the mostly preferred sources of protein, especially in vegetarian diet. One of the most notable biochemical attributes of black gram is Arabinose. As it plays a vital role in the yeast metabolism, it has a direct correlation with the battering quality of Black gram. MDU 1 variety has the highest Arabinose content of 7.5 per cent and VBN(Bg)4yields higher. Both the varieties have indeterminate growth habit. Hence, these two varieties were chosen and treated with Gamma rays and Electron beam of 100–500 Gy and 200–600 Gy respectively. Twenty desirable mutants were selected in M6 generation based on determinate growth habit and high yield with short duration. These mutants were tested for the Arabinose content along with MDU 1 and VBN (Bg)4, using Bial (1902) method. The results of the selected M6 generation mutants revealed that only three mutants excelled in Arabinose content than MDU 1. Two mutants were found to retain the same Arabinose content as that of MDU 1.Three mutants containing higher Arabinose content, one with lower Arabinose content and the parents were further analysed for batter quantity. The unveiled fact is that the increase in Arabinose content increases the batter volume to a certain extent (Arabinose = 10 %). Eventually, with a due course of increase in Arabinose content, the batter volume decreases. The results were tested for significance and were found to be significant. In this present investigation, it was found that the optimum Arabinose content is 10 per cent, which showed an increased batter volume. It has to be further confirmed by using advanced biochemical and molecular methods. (author)

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.

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

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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.

Characterization of a mutated Geobacillus stearothermophilus L-arabinose isomerase that increases the production rate of D-tagatose.

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Kim, H-J; Kim, J-H; Oh, H-J; Oh, D-K

2006-07-01

Characterization of a mutated Geobacillus stearothermophilus L-arabinose isomerase used to increase the production rate of D-tagatose. A mutated gene was obtained by an error-prone polymerase chain reaction using L-arabinose isomerase gene from G. stearothermophilus as a template and the gene was expressed in Escherichia coli. The expressed mutated L-arabinose isomerase exhibited the change of three amino acids (Met322-->Val, Ser393-->Thr, and Val408-->Ala), compared with the wild-type enzyme and was then purified to homogeneity. The mutated enzyme had a maximum galactose isomerization activity at pH 8.0, 65 degrees C, and 1.0 mM Co2+, while the wild-type enzyme had a maximum activity at pH 8.0, 60 degrees C, and 1.0-mM Mn2+. The mutated L-arabinose isomerase exhibited increases in D-galactose isomerization activity, optimum temperature, catalytic efficiency (kcat/Km) for D-galactose, and the production rate of D-tagatose from D-galactose. The mutated L-arabinose isomerase from G. stearothermophilus is valuable for the commercial production of D-tagatose. This work contributes knowledge on the characterization of a mutated L-arabinose isomerase, and allows an increased production rate for D-tagatose from D-galactose using the mutated enzyme.

Bacterial L-arabinose isomerases: industrial application for D-tagatose production.

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Boudebbouze, Samira; Maguin, Emmanuelle; Rhimi, Moez

2011-12-01

D-tagatose is a natural monosaccharide with a low caloric value and has an anti-hyperglycemiant effect. This hexose has potential applications both in pharmaceutical and agro-food industries. However, the use of D-tagatose remains limited by its production cost. Many production procedures including chemical and biological processes were developed and patented. The most profitable production way is based on the use of L-arabinose isomerase which allows the manufacture of D-tagatose with an attractive rate. Future developments are focused on the generation of L-arabinose isomerases having biochemical properties satisfying the industrial applications. This report provides a brief review of the most recent patents that have been published relating to this area.

High production of D-tagatose, a potential sugar substitute, using immobilized L-arabinose isomerase.

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Kim, P; Yoon, S H; Roh, H J; Choi, J H

2001-01-01

An L-arabinose isomerase of Escherichia coli was immobilized using covalent binding to agarose to produce D-tagatose, a bulking sweetener that can be economically used as a sugar substitute. The immobilized L-arabinose isomerase stably produced an average of 7.5 g-tagatose/L.day for 7 days with a productivity exceeding that of the free enzyme (0.47 vs 0.30 mg/U.day). Using a scaled-up immobilized enzyme system, 99.9 g-tagatose/L was produced from galactose with 20% equilibrium in 48 h. The process was repeated two more times with production of 104.1 and 103.5 g-tagatose/L. D-Tagatose production using an immobilized L-arabinose isomerase has a high potential for commercial application.

Comparing the xylose reductase/xylitol dehydrogenase and xylose isomerase pathways in arabinose and xylose fermenting Saccharomyces cerevisiae strains

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Hahn-Hägerdal Bärbel

2008-10-01

Full Text Available Abstract Background Ethanolic fermentation of lignocellulosic biomass is a sustainable option for the production of bioethanol. This process would greatly benefit from recombinant Saccharomyces cerevisiae strains also able to ferment, besides the hexose sugar fraction, the pentose sugars, arabinose and xylose. Different pathways can be introduced in S. cerevisiae to provide arabinose and xylose utilisation. In this study, the bacterial arabinose isomerase pathway was combined with two different xylose utilisation pathways: the xylose reductase/xylitol dehydrogenase and xylose isomerase pathways, respectively, in genetically identical strains. The strains were compared with respect to aerobic growth in arabinose and xylose batch culture and in anaerobic batch fermentation of a mixture of glucose, arabinose and xylose. Results The specific aerobic arabinose growth rate was identical, 0.03 h-1, for the xylose reductase/xylitol dehydrogenase and xylose isomerase strain. The xylose reductase/xylitol dehydrogenase strain displayed higher aerobic growth rate on xylose, 0.14 h-1, and higher specific xylose consumption rate in anaerobic batch fermentation, 0.09 g (g cells-1 h-1 than the xylose isomerase strain, which only reached 0.03 h-1 and 0.02 g (g cells-1h-1, respectively. Whereas the xylose reductase/xylitol dehydrogenase strain produced higher ethanol yield on total sugars, 0.23 g g-1 compared with 0.18 g g-1 for the xylose isomerase strain, the xylose isomerase strain achieved higher ethanol yield on consumed sugars, 0.41 g g-1 compared with 0.32 g g-1 for the xylose reductase/xylitol dehydrogenase strain. Anaerobic fermentation of a mixture of glucose, arabinose and xylose resulted in higher final ethanol concentration, 14.7 g l-1 for the xylose reductase/xylitol dehydrogenase strain compared with 11.8 g l-1 for the xylose isomerase strain, and in higher specific ethanol productivity, 0.024 g (g cells-1 h-1 compared with 0.01 g (g cells-1 h-1

Bioconversion of D-galactose into D-tagatose by expression of L-arabinose isomerase.

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Roh, H J; Kim, P; Park, Y C; Choi, J H

2000-02-01

D-Tagatose is a potential bulking agent in food as a non-calorific sweetener. To produce D-tagatose from cheaper resources, plasmids harbouring the L-arabinose isomerase gene (araA) from Escherichia coli, Bacillus subtilis and Salmonella typhimurium were constructed because L-arabinose isomerase was suggested previously as an enzyme that mediates the bioconversion of galactose into tagatose as well as that of arabinose to ribulose. The constructed plasmids were named pTC101, pTC105 and pTC106, containing araA from E. coli, B. subtilis and S. typhimurium respectively. In the cultures of recombinant E. coli with pTC101, pTC105 and pTC106, tagatose was produced from galactose in 9.9, 7.1 and 6.9% yields respectively. The enzyme extract of E. coli with the plasmid pTC101 also converted galactose into tagatose with a 96.4% yield.

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

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...... 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...... of our knowledge, this is the first report that characterizes the molecular mechanisms for improved mixed-pentose utilization obtained by evolutionary engineering of a recombinant S. cerevisiae strain. Increased transport of pentoses and increased activities of xylose converting enzymes contributed...

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

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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. Copyright © 2015 John Wiley & Sons, Ltd.

Coutilization of D-Glucose, D-Xylose, and L-Arabinose in Saccharomyces cerevisiae by Coexpressing the Metabolic Pathways and Evolutionary Engineering

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Chengqiang Wang

2017-01-01

Full Text Available Efficient and cost-effective fuel ethanol production from lignocellulosic materials requires simultaneous cofermentation of all hydrolyzed sugars, mainly including D-glucose, D-xylose, and L-arabinose. Saccharomyces cerevisiae is a traditional D-glucose fermenting strain and could utilize D-xylose and L-arabinose after introducing the initial metabolic pathways. The efficiency and simultaneous coutilization of the two pentoses and D-glucose for ethanol production in S. cerevisiae still need to be optimized. Previously, we constructed an L-arabinose-utilizing S. cerevisiae BSW3AP. In this study, we further introduced the XI and XR-XDH metabolic pathways of D-xylose into BSW3AP to obtain D-glucose, D-xylose, and L-arabinose cofermenting strain. Benefits of evolutionary engineering: the resulting strain BSW4XA3 displayed a simultaneous coutilization of D-xylose and L-arabinose with similar consumption rates, and the D-glucose metabolic capacity was not decreased. After 120 h of fermentation on mixed D-glucose, D-xylose, and L-arabinose, BSW4XA3 consumed 24% more amounts of pentoses and the ethanol yield of mixed sugars was increased by 30% than that of BSW3AP. The resulting strain BSW4XA3 was a useful chassis for further enhancing the coutilization efficiency of mixed sugars for bioethanol production.

Comparative Genomics Reveals the Regulatory Complexity of Bifidobacterial Arabinose and Arabino-Oligosaccharide Utilization

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Aleksandr A. Arzamasov

2018-04-01

Full Text Available Members of the genus Bifidobacterium are common inhabitants of the human gastrointestinal tract. Previously it was shown that arabino-oligosaccharides (AOS might act as prebiotics and stimulate the bifidobacterial growth in the gut. However, despite the rapid accumulation of genomic data, the precise mechanisms by which these sugars are utilized and associated transcription control still remain unclear. In the current study, we used a comparative genomic approach to reconstruct arabinose and AOS utilization pathways in over 40 bacterial species belonging to the Bifidobacteriaceae family. The results indicate that the gene repertoire involved in the catabolism of these sugars is highly diverse, and even phylogenetically close species may differ in their utilization capabilities. Using bioinformatics analysis we identified potential DNA-binding motifs and reconstructed putative regulons for the arabinose and AOS utilization genes in the Bifidobacteriaceae genomes. Six LacI-family transcriptional factors (named AbfR, AauR, AauU1, AauU2, BauR1 and BauR2 and a TetR-family regulator (XsaR presumably act as local repressors for AOS utilization genes encoding various α- or β-L-arabinofuranosidases and predicted AOS transporters. The ROK-family regulator AraU and the LacI-family regulator AraQ control adjacent operons encoding putative arabinose transporters and catabolic enzymes, respectively. However, the AraQ regulator is universally present in all Bifidobacterium species including those lacking the arabinose catabolic genes araBDA, suggesting its control of other genes. Comparative genomic analyses of prospective AraQ-binding sites allowed the reconstruction of AraQ regulons and a proposed binary repression/activation mechanism. The conserved core of reconstructed AraQ regulons in bifidobacteria includes araBDA, as well as genes from the central glycolytic and fermentation pathways (pyk, eno, gap, tkt, tal, galM, ldh. The current study expands the

Metabolome analysis-based design and engineering of a metabolic pathway in Corynebacterium glutamicum to match rates of simultaneous utilization of D-glucose and L-arabinose.

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Kawaguchi, Hideo; Yoshihara, Kumiko; Hara, Kiyotaka Y; Hasunuma, Tomohisa; Ogino, Chiaki; Kondo, Akihiko

2018-05-17

L-Arabinose is the second most abundant component of hemicellulose in lignocellulosic biomass, next to D-xylose. However, few microorganisms are capable of utilizing pentoses, and catabolic genes and operons enabling bacterial utilization of pentoses are typically subject to carbon catabolite repression by more-preferred carbon sources, such as D-glucose, leading to a preferential utilization of D-glucose over pentoses. In order to simultaneously utilize both D-glucose and L-arabinose at the same rate, a modified metabolic pathway was rationally designed based on metabolome analysis. Corynebacterium glutamicum ATCC 31831 utilized D-glucose and L-arabinose simultaneously at a low concentration (3.6 g/L each) but preferentially utilized D-glucose over L-arabinose at a high concentration (15 g/L each), although L-arabinose and D-glucose were consumed at comparable rates in the absence of the second carbon source. Metabolome analysis revealed that phosphofructokinase and pyruvate kinase were major bottlenecks for D-glucose and L-arabinose metabolism, respectively. Based on the results of metabolome analysis, a metabolic pathway was engineered by overexpressing pyruvate kinase in combination with deletion of araR, which encodes a repressor of L-arabinose uptake and catabolism. The recombinant strain utilized high concentrations of D-glucose and L-arabinose (15 g/L each) at the same consumption rate. During simultaneous utilization of both carbon sources at high concentrations, intracellular levels of phosphoenolpyruvate declined and acetyl-CoA levels increased significantly as compared with the wild-type strain that preferentially utilized D-glucose. These results suggest that overexpression of pyruvate kinase in the araR deletion strain increased the specific consumption rate of L-arabinose and that citrate synthase activity becomes a new bottleneck in the engineered pathway during the simultaneous utilization of D-glucose and L-arabinose. Metabolome analysis

Synthesis and characterization of arabinose-palmitic acid esters by enzymatic esterification

NARCIS (Netherlands)

Pappalardo, Valeria M.; Boeriu, Carmen G.; Zaccheria, Federica; Ravasio, Nicoletta

2017-01-01

The direct esterification of palmitic acid with L-(+)-arabinose has been carried out. The use of Candida antartica lipase B as the catalyst and the choice of suitable solvent and experimental conditions allowed carrying out the reaction successfully. In particular 10% dimethyl-sulfoxide in

Surface activity evaluation of an arabinose ester as water/oil demulsifier at severe conditions of temperature, salinity and pH; Avaliacao da atividade superficial de um ester de arabinose, como desemulsificante agua/oleo, em condicoes severas de temperatura, salinidade e pH

Energy Technology Data Exchange (ETDEWEB)

Borges, Mauricio Rodrigues; Garcia, Rosangela Balaban; Santos, Jaciara Alves dos; Vieira, Mariane; Silva, Luciana Carvalho; Campos, Viviane de Oliveira; Silva, Rayane Araujo da; Santos, Telma Pitanga dos [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil)

2008-07-01

This work had for objective to compare the superficial properties of an arabinose ester, no-ionic, nontoxic, biodegradable, with two commercial products: the first one based on sodium dodecyl sulfate and the second one based on poly-oxy alkylene phenol formaldehyde. The arabinose ester was synthesized on the Petroleum Research Laboratory - UFRN, through enzymatic catalysis by protease from Bacillus subtilis, using arabinose and vegetable oil, in organic medium. In previous work [1], this sugar ester was evaluated as a possible water/oil demulsifier and the results were compared with the results of the commercial product based on poly-oxy alkylene phenol formaldehyde, showing that, for certain reaction conditions, the sugar ester presented better acting (71%) that the commercial product (33%) as demulsifier. In this work, the stability of this arabinose ester was evaluated in severe conditions of temperature, salinity and pH, through superficial tests in a tensiometer, using Wilhelmy plate method and the results were compared with the results obtained for two commercial products above mentioned. (author)

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

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

of the present study showed that the peak plasma concentration, time to reach peak plasma concentration or AUC values of glucose, insulin and C-peptide were not altered after consumption of the test meals. Overall, it was not possible to reproduce the beneficial effects of L-arabinose added to sucrose drinks...... effects on postprandial blood glucose, insulin and C-peptide responses in humans. However, the effects of adding L-arabinose to mixed meals on the indices of glucose control are unknown. The purpose of the present study was to investigate whether the positive effects of L-arabinose added to a sugar drink...... could be reproduced in subjects consuming a mixed meal containing sucrose and/or starch from wheat flour. A total of seventeen healthy men participated in study 1, a randomised, double-blind, cross-over trial. In this study, the subjects consumed two different breakfast meals containing sucrose...

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.

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

Science.gov (United States)

2011-01-01

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 reported the purification and the

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

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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

Purification and characterization of an L-arabinose isomerase from an isolated strain of Geobacillus thermodenitrificans producing D-tagatose.

Science.gov (United States)

Kim, Hye-Jung; Oh, Deok-Kun

2005-11-04

The araA gene, encoding l-arabinose isomerase (AI), from the thermophilic bacterium Geobacillus thermodenitrificans was cloned and expressed in Escherichia coli. Recombinant AI was isolated with a final purity of about 97% and a final specific activity of 2.10 U/mg. The molecular mass of the purified AI was estimated to be about 230 kDa to be a tetramer composed of identical subunits. The AI exhibited maximum activity at 70 degrees C and pH 8.5 in the presence of Mn2+. The enzyme was stable at temperatures below 60 degrees C and within the pH range 7.5-8.0. d-Galactose and l-arabinose as substrate were isomerized with high activities. Ribitol was the strongest competitive inhibitor of AI with a Ki of 5.5mM. The apparent Km and Vmax for L-arabinose were 142 mM and 86 U/mg, respectively, whereas those for d-galactose were 408 mM and 6.9 U/mg, respectively. The catalytic efficiency (kcat/Km) was 48 mM(-1)min(-1) for L-arabinose and 0.5mM(-1)min(-1) for D-galactose. Mn2+ was a competitive activator and increased the thermal stability of the AI. The D-tagatose yield produced by AI from d-galactose was 46% without the addition of Mn2+ and 48% with Mn2+ after 300 min at 65 degrees C.

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

Quantitative investigations of xylose and arabinose substituents in hydroxypropylated and hydroxyvinylethylated arabinoxylans.

Science.gov (United States)

Lorenz, Dominic; Knöpfle, Anna; Akil, Youssef; Saake, Bodo

2017-11-01

The chemical structures obtained by the modification of arabinoxylans with the cyclic carbonates propylene carbonate (PC) and 4-vinyl-1,3-dioxolan-2-one (VEC) with varying degrees of substitution were investigated. Therefore, a new analytical method was developed that is based on a microwave-assisted hydrolysis of the polysaccharides with trifluoroacetic acid and the reductive amination with 2-aminobenzoic acid. The peak assignment was achieved by HPLC-MS and the carbohydrate derivatives were quantified by HPLC-fluorescence. The obtained maximum molar substitution of PC-derivatized xylan (X HP ) was 1.8; the molar substitution of VEC-derivatized xylan (X HVE ) was 2.3. Investigations of xylose and arabinose based mono- and disubstituted derivatives revealed a preferred reaction of the cyclic carbonates with arabinose. Conversion rates were up to 2.4 times higher for monosubstitution and up to 3.0 times for disubstitution compared to xylose. Furthermore, the reaction with VEC was preferred due to higher reactivity of the newly introduced side chains. Copyright © 2017 Elsevier Ltd. All rights reserved.

L-Arabinose isomerase and its use for biotechnological production of rare sugars.

Science.gov (United States)

Xu, Zheng; Li, Sha; Feng, Xiaohai; Liang, Jinfeng; Xu, Hong

2014-11-01

L-Arabinose isomerase (AI), a key enzyme in the microbial pentose phosphate pathway, has been regarded as an important biological catalyst in rare sugar production. This enzyme could isomerize L-arabinose into L-ribulose, as well as D-galactose into D-tagatose. Both the two monosaccharides show excellent commercial values in food and pharmaceutical industries. With the identification of novel AI family members, some of them have exhibited remarkable potential in industrial applications. The biological production processes for D-tagatose and L-ribose (or L-ribulose) using AI have been developed and improved in recent years. Meanwhile, protein engineering techniques involving rational design has effectively enhanced the catalytic properties of various AIs. Moreover, the crystal structure of AI has been disclosed, which sheds light on the understanding of AI structure and catalytic mechanism at molecular levels. This article reports recent developments in (i) novel AI screening, (ii) AI-mediated rare sugar production processes, (iii) molecular modification of AI, and (iv) structural biology study of AI. Based on previous reports, an analysis of the future development has also been initiated.

Enzymatic conversion of D-galactose to D-tagatose: heterologous expression and characterisation of a thermostable L-arabinose isomerase from Thermoanaerobacter mathranii.

Science.gov (United States)

Jørgensen, F; Hansen, O C; Stougaard, P

2004-06-01

The ability to convert D-galactose into D-tagatose was compared among a number of bacterial L-arabinose isomerases ( araA). One of the most efficient enzymes, from the anaerobic thermophilic bacterium Thermoanaerobacter mathranii, was produced heterologously in Escherichia coli and characterised. Amino acid sequence comparisons indicated that this enzyme is only distantly related to the group of previously known araA sequences in which the sequence similarity is evident. The substrate specificity and the Michaelis-Menten constants of the enzyme determined with L-arabinose, D-galactose and D-fucose also indicated that this enzyme is an unusual, versatile L-arabinose isomerase which is able to isomerise structurally related sugars. The enzyme was immobilised and used for production of D-tagatose at 65 degrees C. Starting from a 30% solution of D-galactose, the yield of D-tagatose was 42% and no sugars other than D-tagatose and D-galactose were detected. Direct conversion of lactose to D-tagatose in a single reactor was demonstrated using a thermostable beta-galactosidase together with the thermostable L-arabinose isomerase. The two enzymes were also successfully combined with a commercially available glucose isomerase for conversion of lactose into a sweetening mixture comprising lactose, glucose, galactose, fructose and tagatose.

Cloning, expression and characterization of L-arabinose isomerase from Thermotoga neapolitana: bioconversion of D-galactose to D-tagatose using the enzyme.

Science.gov (United States)

Kim, Byoung-Chan; Lee, Yoon-Hee; Lee, Han-Seung; Lee, Dong-Woo; Choe, Eun-Ah; Pyun, Yu-Ryang

2002-06-18

Gene araA encoding an L-arabinose isomerase (AraA) from the hyperthermophile, Thermotoga neapolitana 5068 was cloned, sequenced, and expressed in Escherichia coli. The gene encoded a polypeptide of 496 residues with a calculated molecular mass of 56677 Da. The deduced amino acid sequence has 94.8% identical amino acids compared with the residues in a putative L-arabinose isomerase of Thermotoga maritima. The recombinant enzyme expressed in E. coli was purified to homogeneity by heat treatment, ion exchange chromatography and gel filtration. The thermophilic enzyme had a maximum activity of L-arabinose isomerization and D-galactose isomerization at 85 degrees C, and required divalent cations such as Co(2+) and Mn(2+) for its activity and thermostability. The apparent K(m) values of the enzyme for L-arabinose and D-galactose were 116 mM (v(max), 119 micromol min(-1) mg(-1)) and 250 mM (v(max), 14.3 micromol min(-1) mg(-1)), respectively, that were determined in the presence of both 1 mM Co(2+) and 1 mM Mn(2+). A 68% conversion of D-galactose to D-tagatose was obtained using the recombinant enzyme at the isomerization temperature of 80 degrees C.

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

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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.

Rational design of Bacillus stearothermophilus US100 L-arabinose isomerase: potential applications for D-tagatose production.

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Rhimi, Moez; Aghajari, Nushin; Juy, Michel; Chouayekh, Hichem; Maguin, Emmanuelle; Haser, Richard; Bejar, Samir

2009-05-01

L-arabinose isomerases catalyze the bioconversion of D-galactose into D-tagatose. With the aim of producing an enzyme optimized for D-tagatose production, three Bacillus stearothermophilus US100 L-arabinose isomerase mutants were constructed, purified and characterized. Our results indicate that mutant Q268K was significantly more acidotolerant and more stable at acidic pH than the wild-type enzyme. The N175H mutant has a broad optimal temperature range from 50 to 65 degrees C. With the aim of constructing an acidotolerant mutant working at relatively low temperatures we generated the Q268K/N175H construct. This double mutant displays an optimal pH in the range 6.0-7.0 and an optimal activity around 50-65 degrees C, temperatures at which the enzyme was stable without addition of metal ions.

Biochemical properties of L-arabinose isomerase from Clostridium hylemonae to produce D-tagatose as a functional sweetener.

Science.gov (United States)

Nguyen, Tien-Kieu; Hong, Moon-Gi; Chang, Pahn-Shick; Lee, Byung-Hoo; Yoo, Sang-Ho

2018-01-01

d-Tagatose has gained substantial interest due to its potential functionalities as a sucrose substitute. In this study, the gene araA, encoding l-arabinose isomerase (l-AI) from Clostridium hylemonae (DSM 15053), was cloned and expressed in Escherichia coli BL21 (DE3). This gene consists of 1,506 nucleotides and encodes a protein of 501 amino acid residues with a calculated molecular mass of 56,554 Da. Since l-AI was expressed as an intracellular inclusion body, this enzyme was solubilized with guanidine hydrochloride, refolded, and activated with a descending concentration gradient of urea. The purified enzyme exhibited the greatest activity at 50°C, pH 7-7.5, and required 1 mM of Mg2+ as a cofactor. Notably, the catalytic efficiency (3.69 mM-1sec-1) of l-AI from C. hylemonae on galactose was significantly greater than that of other previously reported enzymes. The bioconversion yield of d-tagatose using the C. hylemonae l-arabinose isomerase at 60°C reached approximately 46% from 10 mM of d-galactose after 2 h. From these results, it is suggested that the l-arabinose isomerase from C. hylemonae could be utilized as a potential enzyme for d-tagatose production due to its high conversion yield at an industrially competitive temperature.

ARA1 regulates not only l-arabinose but also d-galactose catabolism in Trichoderma reesei

NARCIS (Netherlands)

Benocci, Tiziano; Aguilar-Pontes, Maria Victoria; Kun, Roland Sándor; Seiboth, Bernhard; de Vries, Ronald P; Daly, Paul

2017-01-01

Trichoderma reesei is used to produce saccharifying enzyme cocktails for biofuels. There is limited understanding of the transcription factors (TFs) that regulate genes involved in release and catabolism of l-arabinose and d-galactose, as the main TF XYR1 is only partially involved. Here, the T.

Performance testing of Zymomonas mobilis metabolically engineered for cofermentation of glucose, xylose, and arabinose.

Science.gov (United States)

Lawford, Hugh G; Rousseau, Joyce D

2002-01-01

IOGEN Corporation of Ottawa, Canada, has recently built a 40t/d biomass-to-ethanol demonstration plant adjacent to its enzyme production facility. It has partnered with the University of Toronto to test the C6/C5 cofermenta-tion performance characteristics of the National Renewable Energy Labora-tory's metabolically engineered Zymomonas mobilis using various biomass hydrolysates. IOGEN's feedstocks are primarily agricultural wastes such as corn stover and wheat straw. Integrated recombinant Z. mobilis strain AX101 grows on D-xylose and/or L-arabinose as the sole carbon/energy sources and ferments these pentose sugars to ethanol in high yield. Strain AX101 lacks the tetracycline resistance gene that was a common feature of other recombinant Zm constructs. Genomic integration provides reliable cofermentation performance in the absence of antibiotics, another characteristic making strain AX101 attractive for industrial cellulosic ethanol production. In this work, IOGEN's biomass hydrolysate was simulated by a pure sugar medium containing 6% (w/v) glucose, 3% xylose, and 0.35% arabinose. At a level of 3 g/L (dry solids), corn steep liquor with inorganic nitrogen (0.8 g/L of ammonium chloride or 1.2 g/L of diammonium phosphate) was a cost-effective nutritional supplement. In the absence of acetic acid, the maximum volumetric ethanol productivity of a continuous fermentation at pH 5.0 was 3.54 g/L x h. During prolonged continuous fermentation, the efficiency of sugar-to-ethanol conversion (based on total sugar load) was maintained at >85%. At a level of 0.25% (w/v) acetic acid, the productivity decreased to 1.17 g/L x h at pH 5.5. Unlike integrated, xylose-utilizing rec Zm strain C25, strain AX101 produces less lactic acid as byproduct, owing to the fact that the Escherichia coli arabinose genes are inserted into a region of the host chromosome tentatively assigned to the gene for D-lactic acid dehydrogenase. In pH-controlled batch fermentations with sugar mixtures, the

Enzymatic conversion of D-galactose to D-tagatose: cloning, overexpression and characterization of L-arabinose isomerase from Pediococcus pentosaceus PC-5.

Science.gov (United States)

Men, Yan; Zhu, Yueming; Zhang, Lili; Kang, Zhenkui; Izumori, Ken; Sun, Yuanxia; Ma, Yanhe

2014-01-01

The gene encoding L-arabinose isomerase from food-grade strain Pediococcus pentosaceus PC-5 was cloned and overexpressed in Escherichia coli. The recombinant protein was purified and characterized. It was optimally active at 50 °C and pH 6.0. Furthermore, this enzyme exhibited a weak requirement for metallic ions for its maximal activity evaluated at 0.6 mM Mn(2+) or 0.8 mM Co(2+). Interestingly, this enzyme was distinguished from other L-AIs, it could not use L-arabinose as its substrate. In addition, a three-dimensional structure of L-AI was built by homology modeling and L-arabinose and D-galactose were docked into the active site pocket of PPAI model to explain the interaction between L-AI and its substrate. The purified P. pentosaceus PC-5 L-AI converted D-galactose into D-tagatose with a high conversion rate of 52% after 24 h at 50 °C, suggesting its excellent potential in D-tagatose production. Crown Copyright © 2013. Published by Elsevier GmbH. All rights reserved.

Production of D-tagatose, a low caloric sweetener during milk fermentation using L-arabinose isomerase.

Science.gov (United States)

Rhimi, Moez; Chouayekh, Hichem; Gouillouard, Isabelle; Maguin, Emmanuelle; Bejar, Samir

2011-02-01

Lactobacillusdelbrueckii subsp. bulgaricus and Streptococcus thermophilus are used for the biotransformation of milk in yoghurt. During milk fermentation, these lactic acid bacteria (LAB) hydrolyze lactose producing a glucose moiety that is further metabolized and a galactose moiety that they are enable to metabolize. We investigated the ability of L. bulgaricus and S. thermophilus strains expressing a heterologous L-arabinose isomerase to convert residual D-galactose to D-tagatose. The Bacillus stearothermophilus US100l-arabinose isomerase (US100l-AI) was expressed in both LAB, using a new shuttle vector where the araA US100 gene is under the control of the strong and constitutive promoter of the L. bulgaricus ATCC 11842 hlbA gene. The production of L-AI by these LAB allowed the bioconversion of D-galactose to D-tagatose during fermentation in laboratory media and milk. We also established that the addition of L-AI to milk also allowed the conversion of D-galactose into D-tagatose during the fermentation process. Copyright © 2010 Elsevier Ltd. All rights reserved.

Mechanism of ultraviolet light induced catabolite repression of L-arabinose isomerase

Energy Technology Data Exchange (ETDEWEB)

Bhatnagar, D; Bhattacharya, A K [Banaras Hindu Univ. (India). Inst. of Medical Sciences

1982-12-01

An attempt has been made to find out how U.V. irradiation of E.coli B/r cells causes catabolite repression to inhibit L-arabinose isomerase synthesis. The results presented show that U.V. irradiation leads to a lowering of the cellular cyclic AMP level and of the cyclic AMP binding activity. Unlike catabolite repression by glucose, no small molecular weight compound is involved in U.V. light induced inhibition of the binding activity. It is therefore concluded that the mechanism of catabolite repression induced by U.V. appears to be different from that of the catabolite repression by glucose.

Microbial production of xylitol from xylose and L-arabinose: conversion of L-arabitol to xylitol using bacterial oxidoreductases

Science.gov (United States)

Microbial production of xylitol, using hemicellulosic biomass such as agricultural residues, is becoming more attractive for reducing its manufacturing cost. L-arabitol is a particular problem to xylitol production from hemicellulosic hydrolyzates that contain both xylose and L-arabinose because it...

Statistical Optimization of the Induction of Phytase Production by Arabinose in a recombinant E. coli using Response Surface Methodology

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Abd-El Aziem Farouk

2017-11-01

Full Text Available The production of phytase in a recombinant E.coli using the pBAD expression  system was optimized using response surface methodology with full-factorial faced centered central composite design. The ampicilin and arabinose concentration in the cultivation media and the incubation temperature were optimized in order to maximize phytase production using 2 3  central composite experimental design. With this design the number of actual experiment performed could be reduced while allowing eludidation of possible interactions among these factors. The most significant parameter was shown to be the linear and quadratic effect of the incubation temperature.  Optimal conditions for phytase production were determined to be 100 µg/ml ampicilin, 0.2 % arabinose and an incubation temperature of 37ºC. The production of phytase in the recombinant E. coli was scaled up to 100 ml and 1000 ml.

Characterization of an L-arabinose isomerase from Bacillus thermoglucosidasius for D-tagatose production.

Science.gov (United States)

Seo, Myung-Ji

2013-01-01

L-Arabinose isomerase from Bacillus thermoglucosidasius KCTC 1828 (BTAI) was expressed in Escherichia coli. The optimal temperature and pH for the activity of the purified BTAI were 40 °C and pH 7.0. The Mn(2+) ion was an activator of BTAI activity. The kinetic parameters of BTAI for D-galactose were a K(m) of 175 mM and a k(cat)/K(m) of 2.8 mM(-1)min(-1). The conversion ratio by BTAI to D-tagatose reached 45.6% at 40 °C.

Computer simulation of protein—carbohydrate complexes: application to arabinose-binding protein and pea lectin

Science.gov (United States)

Rao, V. S. R.; Biswas, Margaret; Mukhopadhyay, Chaitali; Balaji, P. V.

1989-03-01

The CCEM method (Contact Criteria and Energy Minimisation) has been developed and applied to study protein-carbohydrate interactions. The method uses available X-ray data even on the native protein at low resolution (above 2.4 Å) to generate realistic models of a variety of proteins with various ligands. The two examples discussed in this paper are arabinose-binding protein (ABP) and pea lectin. The X-ray crystal structure data reported on ABP-β- L-arabinose complex at 2.8, 2.4 and 1.7 Å resolution differ drastically in predicting the nature of the interactions between the protein and ligand. It is shown that, using the data at 2.4 Å resolution, the CCEM method generates complexes which are as good as the higher (1.7 Å) resolution data. The CCEM method predicts some of the important hydrogen bonds between the ligand and the protein which are missing in the interpretation of the X-ray data at 2.4 Å resolution. The theoretically predicted hydrogen bonds are in good agreement with those reported at 1.7 Å resolution. Pea lectin has been solved only in the native form at 3 Å resolution. Application of the CCEM method also enables us to generate complexes of pea lectin with methyl-α- D-glucopyranoside and methyl-2,3-dimethyl-α- D-glucopyranoside which explain well the available experimental data in solution.

Crystal Structure of Mn2+-bound Escherichia coli L-arabinose Isomerase (ECAI) and Implications in Protein Catalytic Mechanism and Thermo-Stability

International Nuclear Information System (INIS)

Zhu, W.; Manjasetty, B.; Chance, M.

2007-01-01

The functional properties of proteins depend on their three-dimensional shapes. Protein structures can be determined by X-ray crystallography as a tool. The three-dimensional structure of the apo form of the Escherichia coli L-arabinose isomerase (ECAI) has recently been determined. ECAI is responsible for the initial stage of L-arabinose catabolism, converting arabinose into ribulose in vivo. This enzyme also plays a crucial role in catalyzing the conversion of galactose into tagatose (low calorie natural sugar) in vitro. ECAI utilizes Mn 2+ for its catalytic activity. Crystals of the ECAI + Mn 2+ complex helps to investigate the catalytic properties of the enzyme. Therefore, crystals of ECAI + Mn 2+ complex were grown using hanging drop vapor diffusion method at room temperature. Diffraction data were collected at X4C beamline, National Synchrotron Light Source, Brookhaven National Laboratory. The structure was solved by the molecular replacement technique and has been refined to Rwork of 0.23 at 2.8 (angstrom) resolution using X3A beamline computational facility. The structure was deposited to Protein Data Bank (PDB ID 2HXG). Mn 2+ ion was localized to the previously identified putative active site with octahedral coordination. Comparison of apo and holo form of ECAI structures permits the identification of structural features that are of importance to the intrinsic activity and heat stability of AI

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.

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

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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. Copyright © 2016 Elsevier Inc. All rights reserved.

Coexpression of β-D-galactosidase and L-arabinose isomerase in the production of D-tagatose: a functional sweetener.

Science.gov (United States)

Zhan, Yijing; Xu, Zheng; Li, Sha; Liu, Xiaoliu; Xu, Lu; Feng, Xiaohai; Xu, Hong

2014-03-19

The functional sweetener, d-tagatose, is commonly transformed from galactose by l-arabinose isomerase. To make use of a much cheaper starting material, lactose, hydrolization, and isomerization are required to take place collaboratively. Therefore, a single-step method involving β-d-galactosidase was explored for d-tagatose production. The two vital genes, β-d-galactosidase gene (lacZ) and l-arabinose isomerase mutant gene (araA') were extracted separately from Escherichia coli strains and incorporated into E. coli simultaneously. This gave us E. coli-ZY, a recombinant producing strain capable of coexpressing the two key enzymes. The resulted cells exhibited maximum d-tagatose producing activity at 34 °C and pH 6.5 and in the presence of borate, 10 mM Fe(2+), and 1 mM Mn(2+). Further monitoring showed that the recombinant cells could hydrolyze more than 95% lactose and convert 43% d-galactose into d-tagatose. This research has verified the feasibility of single-step d-tagatose fermentation, thereby laying down the foundation for industrial usage of lactose.

Production of D-tagatose at high temperatures using immobilized Escherichia coli cells expressing L-arabinose isomerase from Thermotoga neapolitana.

Science.gov (United States)

Hong, Young-Ho; Lee, Dong-Woo; Lee, Sang-Jae; Choe, Eun-Ah; Kim, Seong-Bo; Lee, Yoon-Hee; Cheigh, Chan-Ick; Pyun, Yu-Ryang

2007-04-01

Escherichia coli cells expressing L-arabinose isomerase from Thermotoga neapolitana (TNAI) were immobilized in calcium alginate beads. The resulting cell reactor (2.4 U, t (1/2) = 43 days at 70 degrees C) in a continuous recycling mode at 70 degrees C produced 49 and 38 g D-tagatose/l from 180 and 90 g D-galactose/l, respectively, within 12 h.

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

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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

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

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

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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

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.

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Wanarska, Marta; Kur, Józef

2012-08-23

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. 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 of lactose hydrolysis, the complete utilization

Increase in D-tagatose production rate by site-directed mutagenesis of L-arabinose isomerase from Geobacillus thermodenitrificans.

Science.gov (United States)

Oh, Hyo-Jung; Kim, Hye-Jung; Oh, Deok-Kun

2006-02-01

Among single-site mutations of L-arabinose isomerase derived from Geobacillus thermodenitrificans, two mutants were produced having the lowest and highest activities of D-tagatose production. Site-directed mutagenesis at these sites showed that the aromatic ring at amino acid 164 and the size of amino acid 475 were important for D-tagatose production. Among double-site mutations, one mutant converted D-galactose into D-tagatose with a yield of 58% whereas the wild type gave 46% D-tagatose conversion after 300 min at 65 degrees C.

Continuous D-tagatose production by immobilized thermostable L-arabinose isomerase in a packed-bed bioreactor.

Science.gov (United States)

Ryu, Se-Ah; Kim, Chang Sup; Kim, Hye-Jung; Baek, Dae Heoun; Oh, Deok-Kun

2003-01-01

D-Tagatose was continuously produced using thermostable L-arabinose isomerase immobilized in alginate with D-galactose solution in a packed-bed bioreactor. Bead size, L/D (length/diameter) of reactor, dilution rate, total loaded enzyme amount, and substrate concentration were found to be optimal at 0.8 mm, 520/7 mm, 0.375 h(-1), 5.65 units, and 300 g/L, respectively. Under these conditions, the bioreactor produced about 145 g/L tagatose with an average productivity of 54 g tagatose/L x h and an average conversion yield of 48% (w/w). Operational stability of the immobilized enzyme was demonstrated, with a tagatose production half-life of 24 days.

Thermostable L-arabinose isomerase from Bacillus stearothermophilus IAM 11001 for D-tagatose production: gene cloning, purification and characterisation.

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Cheng, Lifang; Mu, Wanmeng; Jiang, Bo

2010-06-01

D-Tagatose, as one of the rare sugars, has been found to be a natural and safe low-calorie sweetener in food products and is classified as a GRAS substance. L-Arabinose isomerase (L-AI, EC 5.3.1.4), catalysing the isomerisations of L-arabinose and D-galactose to L-ribulose and D-tagatose respectively, is considered to be the most promising enzyme for the production of D-tagatose. The araA gene encoding an L-AI from Bacillus stearothermophilus IAM 11001 was cloned, sequenced and overexpressed in Escherichia coli. The gene is composed of 1491 bp nucleotides and codes for a protein of 496 amino acid residues. The recombinant L-AI was purified to electrophoretical homogeneity by affinity chromatography. The purified enzyme was optimally active at 65 degrees C and pH 7.5 and had an absolute requirement for the divalent metal ion Mn(2+) for both catalytic activity and thermostability. The enzyme was relatively active and stable at acidic pH of 6. The bioconversion yield of D-galactose to D-tagatose by the purified L-AI after 12 h at 65 degrees C reached 36%. The purified L-AI from B. stearothermophilus IAM 11001 was characterised and shown to be a good candidate for potential application in D-tagatose production. Copyright (c) 2010 Society of Chemical Industry.

The photochemical conversion of solar energy into electrical energy: Eosin-Arabinose system

Energy Technology Data Exchange (ETDEWEB)

Gangotri, K.M. [Department of Chemistry, Solar Energy Laboratory, Jai Narain Vyas University, Jodhpur 342 033, Rajasthan (India); Bhimwal, Mukesh Kumar [Solar Energy Laboratory, Jai Narain Vyas University, Jodhpur 342 033, Rajasthan (India)

2010-12-15

A photosensitizer -Eosin and a reductant- Arabinose have been used in the photogalvanic cell for photochemical conversion of solar energy into electrical energy. The generated photopotential and photocurrent are 679.0 mV and 240.0 {mu}A respectively. The maximum power of the cell is 162.96 {mu}W whereas the observed power at power point is 73.08 {mu}W. The conversion efficiency is 0.7026% and the fill factor is 0.2856 at the power point of the photogalvanic cell. The photogalvanic cell so developed can work for 85.0 min in dark if it is irradiated for 140.0 min i.e. the storage capacity of photogalvanic cell is 60.71%. The effects of different parameters on the electrical output of the photogalvanic cell have been observed. A mechanism has also been proposed for the photogeneration of electrical energy. (author)

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

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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.

Enhanced activity and stability of L-arabinose isomerase by immobilization on aminopropyl glass.

Science.gov (United States)

Zhang, Ye-Wang; Jeya, Marimuthu; Lee, Jung-Kul

2011-03-01

Immobilization of Bacillus licheniformis L: -arabinose isomerase (BLAI) on aminopropyl glass modified with glutaraldehyde (4 mg protein g support⁻¹) was found to enhance the enzyme activity. The immobilization yield of BLAI was proportional to the quantity of amino groups on the surface of support. Reducing particle size increased the adsorption capacity (q(m)) and affinity (k(a)). The pH and temperature for immobilization were optimized to be pH 7.1 and 33 °C using response surface methodology (RSM). The immobilized enzyme was characterized and compared to the free enzyme. There is no change in optimal pH and temperature before and after immobilization. However, the immobilized BLAI enzyme achieved 145% of the activity of the free enzyme. Correspondingly, the catalytic efficiency (k(cat)/K(m)) was improved 1.47-fold after immobilization compared to the free enzyme. The thermal stability was improved 138-fold (t₁/₂) increased from 2 to 275 h) at 50 °C following immobilization.

Engineering the l-Arabinose Isomerase from Enterococcus Faecium for d-Tagatose Synthesis.

Science.gov (United States)

de Sousa, Marylane; Manzo, Ricardo M; García, José L; Mammarella, Enrique J; Gonçalves, Luciana R B; Pessela, Benevides C

2017-12-06

l-Arabinose isomerase (EC 5.3.1.4) (l-AI) from Enterococcus faecium DBFIQ E36 was overproduced in Escherichia coli by designing a codon-optimized synthetic araA gene. Using this optimized gene, two N- and C-terminal His-tagged-l-AI proteins were produced. The cloning of the two chimeric genes into regulated expression vectors resulted in the production of high amounts of recombinant N -His-l-AI and C -His-l-AI in soluble and active forms. Both His-tagged enzymes were purified in a single step through metal-affinity chromatography and showed different kinetic and structural characteristics. Analytical ultracentrifugation revealed that C -His-l-AI was preferentially hexameric in solution, whereas N -His-l-AI was mainly monomeric. The specific activity of the N -His-l-AI at acidic pH was higher than that of C -His-l-AI and showed a maximum bioconversion yield of 26% at 50 °C for d-tagatose biosynthesis, with Km and Vmax parameters of 252 mM and 0.092 U mg -1 , respectively. However, C -His-l-AI was more active and stable at alkaline pH than N -His-l-AI. N -His-l-AI follows a Michaelis-Menten kinetic, whereas C -His-l-AI fitted to a sigmoidal saturation curve.

Synthesis and modifications of heterocyclic derivatives of D-arabinose: potential inhibitors of glucose-6-phosphate isomerase and glucosamine-6-phosphate synthase

International Nuclear Information System (INIS)

Viana, Renato Marcio Ribeiro; Prado, Maria Auxiliadora Fontes; Alves, Ricardo Jose

2008-01-01

The synthesis of -5-(D-arabino-1,2,3,4-tetrahydroxybutyl)tetrazole and -2-(d-arabino-1,2,3,4-tetra-acetoxybutyl)-5-methyl-1,3,4-oxadiazole from d-arabinose is described. Attempts at removing the protecting groups of the oxadiazole derivative were unsuccessful, leading to products resulting from the opening of the oxadiazole ring. The unprotected tetrazole derivative was selectively phosphorylated at the primary hydroxyl group with diethyl phosphoryl chloride. The resulting 5-[d-arabino-4-(diethylphosphoryloxy)-1,2,3-trihydroxybutyl]tetrazole is a protected form of a potential inhibitor of the enzymes glucose-6-phosphate isomerase and glucosamine synthase. (author)

The ß-1,4-endogalactanase A gene from Aspergillus niger is specifically induced on arabinose and galacturonic acid and plays an important role in the degradation of pectic hairy regions

NARCIS (Netherlands)

Vries, de R.P.; Parenicova, L.; Hinz, S.W.A.; Kester, H.C.M.; Beldman, G.; Benen, J.A.E.; Visser, J.

2002-01-01

The Aspergillus nigerß-1,4-endogalactanase encoding gene (galA) was cloned and characterized. The expression of galA in A. niger was only detected in the presence of sugar beet pectin, d-galacturonic acid and l-arabinose, suggesting that galA is coregulated with both the pectinolytic genes as well

Creation of metal-independent hyperthermophilic L-arabinose isomerase by homologous recombination.

Science.gov (United States)

Hong, Young-Ho; Lee, Dong-Woo; Pyun, Yu-Ryang; Lee, Sung Haeng

2011-12-28

Hyperthermophilic L-arabinose isomerases (AIs) are useful in the commercial production of D-tagatose as a low-calorie bulk sweetener. Their catalysis and thermostability are highly dependent on metals, which is a major drawback in food applications. To study the role of metal ions in the thermostability and catalysis of hyperthermophilic AI, four enzyme chimeras were generated by PCR-based hybridization to replace the variable N- and C-terminal regions of hyperthermophilic Thermotoga maritima AI (TMAI) and thermophilic Geobacillus stearothermophilus AI (GSAI) with those of the homologous mesophilic Bacillus halodurans AI (BHAI). Unlike Mn(2+)-dependent TMAI, the GSAI- and TMAI-based hybrids with the 72 C-terminal residues of BHAI were not metal-dependent for catalytic activity. By contrast, the catalytic activities of the TMAI- and GSAI-based hybrids containing the N-terminus (residues 1-89) of BHAI were significantly enhanced by metals, but their thermostabilities were poor even in the presence of Mn(2+), indicating that the effects of metals on catalysis and thermostability involve different structural regions. Moreover, in contrast to the C-terminal truncate (Δ20 residues) of GSAI, the N-terminal truncate (Δ7 residues) exhibited no activity due to loss of its native structure. The data thus strongly suggest that the metal dependence of the catalysis and thermostability of hyperthermophilic AIs evolved separately to optimize their activity and thermostability at elevated temperatures. This may provide effective target regions for engineering, thereby meeting industrial demands for the production of d-tagatose.

Bioconversion of D-galactose to D-tagatose: continuous packed bed reaction with an immobilized thermostable L-arabinose isomerase and efficient purification by selective microbial degradation.

Science.gov (United States)

Liang, Min; Chen, Min; Liu, Xinying; Zhai, Yafei; Liu, Xian-wei; Zhang, Houcheng; Xiao, Min; Wang, Peng

2012-02-01

The continuous enzymatic conversion of D-galactose to D-tagatose with an immobilized thermostable L-arabinose isomerase in packed-bed reactor and a novel method for D-tagatose purification were studied. L-arabinose isomerase from Thermoanaerobacter mathranii (TMAI) was recombinantly overexpressed and immobilized in calcium alginate. The effects of pH and temperature on D-tagatose production reaction catalyzed by free and immobilized TMAI were investigated. The optimal condition for free enzyme was pH 8.0, 60°C, 5 mM MnCl(2). However, that for immobilized enzyme was pH 7.5, 75°C, 5 mM MnCl(2). In addition, the catalytic activity of immobilized enzyme at high temperature and low pH was significantly improved compared with free enzyme. The optimum reaction yield with immobilized TMAI increased by four percentage points to 43.9% compared with that of free TMAI. The highest productivity of 10 g/L h was achieved with the yield of 23.3%. Continuous production was performed at 70°C; after 168 h, the reaction yield was still above 30%. The resultant syrup was then incubated with Saccharomyces cerevisiae L1 cells. The selective degradation of D-galactose was achieved, obtaining D-tagatose with the purity above 95%. The established production and separation methods further potentiate the industrial production of D-tagatose via bioconversion and biopurification processes.

Engineering the l-Arabinose Isomerase from Enterococcus Faecium for d-Tagatose Synthesis

Directory of Open Access Journals (Sweden)

Marylane de Sousa

2017-12-01

Full Text Available l-Arabinose isomerase (EC 5.3.1.4 (l-AI from Enterococcus faecium DBFIQ E36 was overproduced in Escherichia coli by designing a codon-optimized synthetic araA gene. Using this optimized gene, two N- and C-terminal His-tagged-l-AI proteins were produced. The cloning of the two chimeric genes into regulated expression vectors resulted in the production of high amounts of recombinant N-His-l-AI and C-His-l-AI in soluble and active forms. Both His-tagged enzymes were purified in a single step through metal-affinity chromatography and showed different kinetic and structural characteristics. Analytical ultracentrifugation revealed that C-His-l-AI was preferentially hexameric in solution, whereas N-His-l-AI was mainly monomeric. The specific activity of the N-His-l-AI at acidic pH was higher than that of C-His-l-AI and showed a maximum bioconversion yield of 26% at 50 °C for d-tagatose biosynthesis, with Km and Vmax parameters of 252 mM and 0.092 U mg−1, respectively. However, C-His-l-AI was more active and stable at alkaline pH than N-His-l-AI. N-His-l-AI follows a Michaelis-Menten kinetic, whereas C-His-l-AI fitted to a sigmoidal saturation curve.

The beta-1,4-endogalactanase A gene from Aspergillus niger is specifically induced on arabinose and galacturonic acid and plays an important role in the degradation of pectic hairy regions.

Science.gov (United States)

De Vries, Ronald P; Parenicová, Lucie; Hinz, Sandra W A; Kester, Harry C M; Beldman, Gerrit; Benen, Jacques A E; Visser, Jaap

2002-10-01

The Aspergillus nigerbeta-1,4-endogalactanase encoding gene (galA) was cloned and characterized. The expression of galA in A. niger was only detected in the presence of sugar beet pectin, d-galacturonic acid and l-arabinose, suggesting that galA is coregulated with both the pectinolytic genes as well as the arabinanolytic genes. The corresponding enzyme, endogalactanase A (GALA), contains both active site residues identified previously for the Pseudomonas fluorescensbeta-1,4-endogalactanase. The galA gene was overexpressed to facilitate purification of GALA. The enzyme has a molecular mass of 48.5 kDa and a pH optimum between 4 and 4.5. Incubations of arabinogalactans of potato, onion and soy with GALA resulted initially in the release of d-galactotriose and d-galactotetraose, whereas prolonged incubation resulted in d-galactose and d-galactobiose, predominantly. MALDI-TOF analysis revealed the release of l-arabinose substituted d-galacto-oligosaccharides from soy arabinogalactan. This is the first report of the ability of a beta-1,4-endogalactanase to release substituted d-galacto-oligosaccharides. GALA was not active towards d-galacto-oligosaccharides that were substituted with d-glucose at the reducing end.

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

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)....

Structures of Saccharomyces cerevisiae D-arabinose dehydrogenase Ara1 and its complex with NADPH: implications for cofactor-assisted substrate recognition.

Science.gov (United States)

Hu, Xiao-Qian; Guo, Peng-Chao; Ma, Jin-Di; Li, Wei-Fang

2013-11-01

The primary role of yeast Ara1, previously mis-annotated as a D-arabinose dehydrogenase, is to catalyze the reduction of a variety of toxic α,β-dicarbonyl compounds using NADPH as a cofactor at physiological pH levels. Here, crystal structures of Ara1 in apo and NADPH-complexed forms are presented at 2.10 and 2.00 Å resolution, respectively. Ara1 exists as a homodimer, each subunit of which adopts an (α/β)8-barrel structure and has a highly conserved cofactor-binding pocket. Structural comparison revealed that induced fit upon NADPH binding yielded an intact active-site pocket that recognizes the substrate. Moreover, the crystal structures combined with computational simulation defined an open substrate-binding site to accommodate various substrates that possess a dicarbonyl group.

[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.

Effect of Brönsted acidic ionic liquid 1-(1-propylsulfonic)-3-methylimidazolium chloride on growth and co-fermentation of glucose, xylose and arabinose by Zymomonas mobilis AX101.

Science.gov (United States)

Gyamerah, M; Ampaw-Asiedu, M; Mackey, J; Menezes, B; Woldesenbet, S

2018-06-01

The potential of large-scale lignocellulosic biomass hydrolysis to fermentable sugars using ionic liquids has increased interest in this green chemistry route to fermentation for fuel-ethanol production. The ionic liquid 1-(1-propylsulfonic)-3-methylimidazolium chloride compared to other reported ionic liquids has the advantage of hydrolysing lignocellulosic biomass to reducing sugars at catalytic concentrations (≤0·032 mol l -1 ) in a single step. However, effects of this ionic liquid on co-fermentation of glucose, xylose and arabinose to ethanol by recombinant Zymomonas mobilisAX101 has not been studied. Authentic glucose, xylose and arabinose were used to formulate fermentation media at varying catalytic 1-(1-propylsulfonic)-3-methylimidazolium chloride concentrations for batch co-fermentation of the sugars using Z. mobilisAX101. The results showed that at 0·008, 0·016 and 0·032 mol l -1 ionic liquid in the culture medium, cell growth decreased by 10, 27 and 67% respectively compared to the control. Ethanol yields were 62·6, 61·8, 50·5 and 23·1% for the control, 0·008, 0·016 and 0·032 mol l -1 ionic liquid respectively. The results indicate that lignocellulosic biomass hydrolysed using 0·008 mol l -1 of 1-(1-propylsulfonic)-3-methylimidazolium chloride would eliminate an additional separation step and provide a ready to use fermentation substrate. This is the first reported study of the effect of the Brönsted acidic ionic liquid 1-(1-propylsulfonic)-3-methylimidazolium chloride on growth and co-fermentation of glucose, xylose and arabinose by Zymomonas mobilisAX101 in batch culture. Growth on and co-fermentation of the sugars by Z. mobilisAX 101 with no significant inhibition by the ionic liquid at the same catalytic amounts of 0·008 mol l -1 used to hydrolyse lignocellulosic biomass to reducing sugars overcome two major hurdles that adversely affect the process economics of large-scale industrial cellulosic fuel ethanol production

Characterization of an L-arabinose isomerase from Bacillus coagulans NL01 and its application for D-tagatose production.

Science.gov (United States)

Mei, Wending; Wang, Lu; Zang, Ying; Zheng, Zhaojuan; Ouyang, Jia

2016-06-30

L-arabinose isomerase (AI) is a crucial catalyst for the biotransformation of D-galactose to D-tagatose. In previous reports, AIs from thermophilic bacterial strains had been wildly researched, but the browning reaction and by-products formed at high temperatures restricted their applications. By contrast, AIs from mesophilic Bacillus strains have some different features including lower optimal temperatures and lower requirements of metallic cofactors. These characters will be beneficial to the development of a more energy-efficient and safer production process. However, the relevant data about the kinetics and reaction properties of Bacillus AIs in D-tagatose production are still insufficient. Thus, in order to support further applications of these AIs, a comprehensive characterization of a Bacillus AI is needed. The coding gene (1422 bp) of Bacillus coagulans NL01 AI (BCAI) was cloned and overexpressed in the Escherichia coli BL21 (DE3) strain. The enzymatic property test showed that the optimal temperature and pH of BCAI were 60 °C and 7.5 respectively. The raw purified BCAI originally showed high activity in absence of outsourcing metallic ions and its thermostability did not change in a low concentration (0.5 mM) of Mn(2+) at temperatures from 70 °C to 90 °C. Besides these, the catalytic efficiencies (k cat/K m) for L-arabinose and D-galactose were 8.7 mM(-1) min(-1) and 1.0 mM(-1) min(-1) respectively. Under optimal conditions, the recombinant E. coli cell containing BCAI could convert 150 g L(-1) and 250 g L(-1) D-galactose to D-tagatose with attractive conversion rates of 32 % (32 h) and 27 % (48 h). In this study, a novel AI from B. coagulans NL01was cloned, purified and characterized. Compared with other reported AIs, this AI could retain high proportions of activity at a broader range of temperatures and was less dependent on metallic cofactors such as Mn(2+). Its substrate specificity was understood deeply by carrying out molecular

D-Tagatose production in the presence of borate by resting Lactococcus lactis cells harboring Bifidobacterium longum L-arabinose isomerase.

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Salonen, Noora; Salonen, Kalle; Leisola, Matti; Nyyssölä, Antti

2013-04-01

Bifidobacterium longum NRRL B-41409 L-arabinose isomerase (L-AI) was overexpressed in Lactococcus lactis using a phosphate depletion inducible expression system. The resting L. lactis cells harboring the B. longum L-AI were used for production of D-tagatose from D-galactose in the presence of borate buffer. Multivariable analysis suggested that high pH, temperature and borate concentration favoured the conversion of D-galactose to D-tagatose. Almost quantitative conversion (92 %) was achieved at 20 g L⁻¹ substrate and at 37.5 °C after 5 days. The D-tagatose production rate of 185 g L⁻¹ day ⁻¹ was obtained at 300 g L⁻¹ galactose, at 1.15 M borate, and at 41 °C during 10 days when the production medium was changed every 24 h. There was no significant loss in productivity during ten sequential 24 h batches. The initial D-tagatose production rate was 290 g L⁻¹ day⁻¹ under these conditions.

Metabolic Profiling Reveals Differences in Plasma Concentrations of Arabinose and Xylose after Consumption of Fiber-Rich Pasta and Wheat Bread with Differential Rates of Systemic Appearance of Exogenous Glucose in Healthy Men.

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Pantophlet, Andre J; Wopereis, Suzan; Eelderink, Coby; Vonk, Roel J; Stroeve, Johanna H; Bijlsma, Sabina; van Stee, Leo; Bobeldijk, Ivana; Priebe, Marion G

2017-02-01

The consumption of products rich in cereal fiber and with a low glycemic index is implicated in a lower risk of metabolic diseases. Previously, we showed that the consumption of fiber-rich pasta compared with bread resulted in a lower rate of appearance of exogenous glucose and a lower glucose clearance rate quantified with a dual-isotope technique, which was in accordance with a lower insulin and glucose-dependent insulinotropic polypeptide response. To gain more insight into the acute metabolic consequences of the consumption of products resulting in differential glucose kinetics, postprandial metabolic profiles were determined. In a crossover study, 9 healthy men [mean ± SEM age: 21 ± 0.5 y; mean ± SEM body mass index (kg/m 2 ): 22 ± 0.5] consumed wheat bread (132 g) and fresh pasta (119 g uncooked) enriched with wheat bran (10%) meals. A total of 134 different metabolites in postprandial plasma samples (at -5, 30, 60, 90, 120, and 180 min) were quantified by using a gas chromatography-mass spectrometry-based metabolomics approach (secondary outcomes). Two-factor ANOVA and advanced multivariate statistical analysis (partial least squares) were applied to detect differences between both food products. Forty-two different postprandial metabolite profiles were identified, primarily representing pathways related to protein and energy metabolism, which were on average 8% and 7% lower after the men consumed pasta rather than bread, whereas concentrations of arabinose and xylose were 58% and 53% higher, respectively. Arabinose and xylose are derived from arabinoxylans, which are important components of wheat bran. The higher bioavailability of arabinose and xylose after pasta intake coincided with a lower rate of appearance of glucose and amino acids. We speculate that this higher bioavailability is due to higher degradation of arabinoxylans by small intestinal microbiota, facilitated by the higher viscosity of arabinoxylans after pasta intake than after bread

The acid tolerant L-arabinose isomerase from the food grade Lactobacillus sakei 23K is an attractive D-tagatose producer.

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Rhimi, Moez; Ilhammami, Rimeh; Bajic, Goran; Boudebbouze, Samira; Maguin, Emmanuelle; Haser, Richard; Aghajari, Nushin

2010-12-01

The araA gene encoding an L-arabinose isomerase (L-AI) from the psychrotrophic and food grade Lactobacillus sakei 23K was cloned, sequenced and over-expressed in Escherichia coli. The recombinant enzyme has an apparent molecular weight of nearly 220 kDa, suggesting it is a tetramer of four 54 kDa monomers. The enzyme is distinguishable from previously reported L-AIs by its high activity and stability at temperatures from 4 to 40 degrees C, and pH from 3 to 8, and by its low metal requirement of only 0.8 mM Mn(2+) and 0.8 mM Mg(2+) for its maximal activity and thermostability. Enzyme kinetic studies showed that this enzyme displays a high catalytic efficiency allowing D-galactose bioconversion rates of 20% and 36% at 10 and 45 degrees C, respectively, which are useful for commercial production of D-tagatose. 2010 Elsevier Ltd. All rights reserved.

Identification and characterization of a novel L-arabinose isomerase from Anoxybacillus flavithermus useful in D-tagatose production.

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Li, Yanjun; Zhu, Yueming; Liu, Anjun; Sun, Yuanxia

2011-05-01

D-Tagatose is a highly functional rare ketohexose and many attempts have been made to convert D-galactose into the valuable D-tagatose using L-arabinose isomerase (L-AI). In this study, a thermophilic strain possessing L-AI gene was isolated from hot spring sludge and identified as Anoxybacillus flavithermus based on its physio-biochemical characterization and phylogenetic analysis of its 16s rRNA gene. Furthermore, the gene encoding L-AI from A. flavithermus (AFAI) was cloned and expressed at a high level in E. coli BL21(DE3). L-AI had a molecular weight of 55,876 Da, an optimum pH of 10.5 and temperature of 95°C. The results showed that the conversion equilibrium shifted to more D-tagatose from D-galactose by raising the reaction temperatures and adding borate. A 60% conversion of D-galactose to D-tagatose was observed at an isomerization temperature of 95°C with borate. The catalytic efficiency (k (cat) /K (m)) for D-galactose with borate was 9.47 mM(-1) min(-1), twice as much as that without borate. Our results indicate that AFAI is a novel hyperthermophilic and alkaliphilic isomerase with a higher catalytic efficiency for D-galactose, suggesting its great potential for producing D-tagatose.

Rational Design of Bacillus coagulans NL01 l-Arabinose Isomerase and Use of Its F279I Variant in d-Tagatose Production.

Science.gov (United States)

Zheng, Zhaojuan; Mei, Wending; Xia, Meijuan; He, Qin; Ouyang, Jia

2017-06-14

d-Tagatose is a prospective functional sweetener that can be produced by l-arabinose isomerase (AI) from d-galactose. To improve the activity of AI toward d-galactose, the AI of Bacillus coagulans was rationally designed on the basis of molecular modeling and docking. After alanine scanning and site-saturation mutagenesis, variant F279I that exhibited improved activity toward d-galactose was obtained. The optimal temperature and pH of F279I were determined to be 50 °C and 8.0, respectively. This variant possessed 1.4-fold catalytic efficiency compared with the wild-type (WT) enzyme. The recombinant Escherichia coli overexpressing F279I also showed obvious advantages over the WT in biotransformation. Under optimal conditions, 67.5 and 88.4 g L -1 d-tagatose could be produced from 150 and 250 g L -1 d-galactose, respectively, in 15 h. The biocatalyst constructed in this study presents a promising alternative for large-scale d-tagatose production.

Mechanistic study of oxidation of d-arabinose by N-bromophthalimide in presence of micro-amount of chloro-complex of Ru(III as a homogeneous catalyst

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Neerja Sachdev

2017-11-01

Full Text Available The kinetics and mechanism of Ru(III-catalyzed oxidation of d-arabinose (d-Ara by N-bromophthalimide (NBP in a acidic medium were investigated using titrimetric method for the redox reaction in the temperature range of 303–323 K. The reaction was first order with respect to [NBP] and [Ru(III]. In both cases, the reaction followed identical kinetics with positive fractional order for [d-Ara] and [H+]. Negative effect with increase in [Cl−], [CH3COOH] and [acetonitrile] could also be observed. Erythronic acid and formic acid were identified as main oxidation products of the reaction. Reduced product of the oxidant i.e. phthalimide did not show significant effect on oxidation rate. Various activation parameters have also been evaluated. Finally a plausible mechanism has been proposed from the kinetic results, reaction stoichiometry and product analysis.

A feasible enzymatic process for D-tagatose production by an immobilized thermostable L-arabinose isomerase in a packed-bed bioreactor.

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Kim, Hye-Jung; Ryu, Se-Ah; Kim, Pil; Oh, Deok-Kun

2003-01-01

To develop a feasible enzymatic process for d-tagatose production, a thermostable l-arabinose isomerase, Gali152, was immobilized in alginate, and the galactose isomerization reaction conditions were optimized. The pH and temperature for the maximal galactose isomerization reaction were pH 8.0 and 65 degrees C in the immobilized enzyme system and pH 7.5 and 60 degrees C in the free enzyme system. The presence of manganese ion enhanced galactose isomerization to tagatose in both the free and immobilized enzyme systems. The immobilized enzyme was more stable than the free enzyme at the same pH and temperature. Under stable conditions of pH 8.0 and 60 degrees C, the immobilized enzyme produced 58 g/L of tagatose from 100 g/L galactose in 90 h by batch reaction, whereas the free enzyme produced 37 g/L tagatose due to its lower stability. A packed-bed bioreactor with immobilized Gali152 in alginate beads produced 50 g/L tagatose from 100 g/L galactose in 168 h, with a productivity of 13.3 (g of tagatose)/(L-reactor.h) in continuous mode. The bioreactor produced 230 g/L tagatose from 500 g/L galactose in continuous recycling mode, with a productivity of 9.6 g/(L.h) and a conversion yield of 46%.

Expression of the major outer membrane protein (MOMP) of Chlamydophila abortus, Chlamydophila pecorum, and Chlamydia suis in Escherichia coli using an arabinose-inducible plasmid vector.

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Hoelzle, L E; Hoelzle, K; Wittenbrink, M M

2003-10-01

The ompA genes encoding the 40 kDa major outer membrane protein (MOMP) of Chlamydophila (Ch.) abortus, Ch. pecorum, and Chlamydia (C.) suis were cloned into the arabinose-inducible plasmid vector pBADMycHis, and recombinant MOMPs (rMOMP) from the three chlamydial species were expressed at high levels in Escherichia (E.) coli. The proteins lacking the 22 aa N-terminal signal peptide were expressed as insoluble cytoplasmic inclusion bodies which were readily purified using immobilized metal-affinity chromatography. The rMOMPs including the N-terminal signal peptide were expressed and translocated as a surface-exposed immunoaccessible protein into the outer membrane of E. coli. Transformants expressing this full-length rMOMP were significantly reduced in viability. Purified native elementary bodies (EB) and rMOMPs of the three chlamydial species purified from the E. coli cytoplasm were used for immunization of rabbits. The resulting sera were analysed for their ability to recognize homologous and heterologous rMOMP and native EB. When testing rMOMP antisera against rMOMP and EB antigens, marked cross-reactivities were detected between the three species. Using EB antisera and rMOMPs as antigens, a significant species-specific reactivity was measured.

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

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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

l-Arabinose Isomerase and d-Xylose Isomerase from Lactobacillus reuteri: Characterization, Coexpression in the Food Grade Host Lactobacillus plantarum, and Application in the Conversion of d-Galactose and d-Glucose

Science.gov (United States)

2014-01-01

The l-arabinose isomerase (l-AI) and the d-xylose isomerase (d-XI) encoding genes from Lactobacillus reuteri (DSMZ 17509) were cloned and overexpressed in Escherichia coli BL21 (DE3). The proteins were purified to homogeneity by one-step affinity chromatography and characterized biochemically. l-AI displayed maximum activity at 65 °C and pH 6.0, whereas d-XI showed maximum activity at 65 °C and pH 5.0. Both enzymes require divalent metal ions. The genes were also ligated into the inducible lactobacillal expression vectors pSIP409 and pSIP609, the latter containing a food grade auxotrophy marker instead of an antibiotic resistance marker, and the l-AI- and d-XI-encoding sequences/genes were coexpressed in the food grade host Lactobacillus plantarum. The recombinant enzymes were tested for applications in carbohydrate conversion reactions of industrial relevance. The purified l-AI converted d-galactose to d-tagatose with a maximum conversion rate of 35%, and the d-XI isomerized d-glucose to d-fructose with a maximum conversion rate of 48% at 60 °C. PMID:24443973

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. Copyright © 2013 Elsevier Inc. All rights reserved.

Immediate perception of a reward is distinct from the reward’s long-term salience

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McGinnis, John P; Jiang, Huoqing; Agha, Moutaz Ali; Sanchez, Consuelo Perez; Lange, Jeff; Yu, Zulin; Marion-Poll, Frederic; Si, Kausik

2016-01-01

Reward perception guides all aspects of animal behavior. However, the relationship between the perceived value of a reward, the latent value of a reward, and the behavioral response remains unclear. Here we report that, given a choice between two sweet and chemically similar sugars—L- and D-arabinose—Drosophila melanogaster prefers D- over L- arabinose, but forms long-term memories of L-arabinose more reliably. Behavioral assays indicate that L-arabinose-generated memories require sugar receptor Gr43a, and calcium imaging and electrophysiological recordings indicate that L- and D-arabinose differentially activate Gr43a-expressing neurons. We posit that the immediate valence of a reward is not always predictive of the long-term reinforcement value of that reward, and that a subset of sugar-sensing neurons may generate distinct representations of similar sugars, allowing for rapid assessment of the salient features of various sugar rewards and generation of reward-specific behaviors. However, how sensory neurons communicate information about L-arabinose quality and concentration—features relevant for long-term memory—remains unknown. DOI: http://dx.doi.org/10.7554/eLife.22283.001 PMID:28005005

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

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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.

Anatomy and cell wall polysaccharides of almond (Prunus dulcis D. A. Webb) seeds.

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Dourado, Fernando; Barros, António; Mota, Manuel; Coimbra, Manuel A; Gama, Francisco M

2004-03-10

The anatomy of Prunus dulcis was analyzed by applying several differential staining techniques and light microscopy. Prunus dulcis seed has a thin and structurally complex seed coat, with lignified cellulosic tissue. The embryo has two voluminous cotyledons. Cotyledon cells have a high number of protein and lipid bodies, some of which have phytin. The provascular tissue, located in the cotyledons, is oriented in small bundles perpendicular to the transverse embryonic axis. Prunus dulcis cell wall material is very rich in arabinose (45 mol %). Glucose (23%), uronic acids (12%), and xylose (12%) are also major sugar components. The polymers obtained from the imidazole and Na(2)CO(3) extracts contain mainly pectic substances rich in arabinose, but the sugar content of these extracts was very low. The majority of the pectic substances (also rich in arabinose) was recovered with the KOH extracts. These extracts, with high sugar content, yielded also xyloglucans and acidic xylans. The 4 M KOH + H(3)BO(3) extracts yielded polysaccharides rich in uronic acids and xylose and very rich in arabinose, accounting for 27% of the cell wall material.

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...... α-l-arabinofuranosidases catalyze liberation of arabinose residues linked 1→3 to singly (AFAn) or doubly (AFBa) substituted xyloses in arabinoxylan, respectively. When added to arabinoxylan at equimolar levels, the AFBa enzyme catalyzed the release of more arabinose, i.e. had a higher rate constant...... than AFAn, but with respect to the xylose release, AFAn – as expected – exhibited a better synergistic effect than AFBa with β-xylosidase. This synergistic effect with AFAn was estimated to increase the number of β-xylosidase catalyzed cuts from ∼3 (with β-xylosidase alone) to ∼7 in each arabinoxylan...

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

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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.

Regulated programmed lysis of recombinant Salmonella in host tissues to release protective antigens and confer biological containment.

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Kong, Wei; Wanda, Soo-Young; Zhang, Xin; Bollen, Wendy; Tinge, Steven A; Roland, Kenneth L; Curtiss, Roy

2008-07-08

We have devised and constructed a biological containment system designed to cause programmed bacterial cell lysis with no survivors. We have validated this system, using Salmonella enterica serovar Typhimurium vaccines for antigen delivery after colonization of host lymphoid tissues. The system is composed of two parts. The first component is Salmonella typhimurium strain chi8937, with deletions of asdA and arabinose-regulated expression of murA, two genes required for peptidoglycan synthesis and additional mutations to enhance complete lysis and antigen delivery. The second component is plasmid pYA3681, which encodes arabinose-regulated murA and asdA expression and C2-regulated synthesis of antisense asdA and murA mRNA transcribed from the P22 P(R) promoter. An arabinose-regulated c2 gene is present in the chromosome. chi8937(pYA3681) exhibits arabinose-dependent growth. Upon invasion of host tissues, an arabinose-free environment, transcription of asdA, murA, and c2 ceases, and concentrations of their gene products decrease because of cell division. The drop in C2 concentration results in activation of P(R), driving synthesis of antisense mRNA to block translation of any residual asdA and murA mRNA. A highly antigenic alpha-helical domain of Streptococcus pneumoniae Rx1 PspA was cloned into pYA3681, resulting in pYA3685 to test antigen delivery. Mice orally immunized with chi8937(pYA3685) developed antibody responses to PspA and Salmonella outer membrane proteins. No viable vaccine strain cells were detected in host tissues after 21 days. This system has potential applications with other Gram-negative bacteria in which biological containment would be desirable.

Reactions of saccharides catalyzed by molybdate ions. XXXIII. Use of. cap alpha. (U-/sup 14/C)glucan for preparation of /sup 14/C-labelled saccharides

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Bilik, V; Biely, P [Institute of Chemistry, Centre for Chemical Research, Slovak Academy of Sciences, Bratislava (Czechoslovakia); Kolina, J [Ustav pro Vyzkum, Vyrobu a Vyuziti Radioisotopu, Prague (Czechoslovakia)

1984-01-01

D-(U-/sup 14/C)glucose obtained in acid hydrolysis of ..cap alpha..-(U-/sup 14/C)glucan (2 M-HCl) was epimerized under a catalytic action of molybdate ions to D-(U-/sup 14/C)mannose isolated with a 20% yield. Oxidative degradation of 4-nitrophenylhydrazones of D-(U-/sup 14/C)arabinose and D-(U-/sup 14/C)xylose resulted in D-(U-/sup 14/C)erythrose and D-(U-/sup 14/C)threose, respectively, with a 15% yield relative to the starting aldopentoses. Nitromethane synthesis with D-(U-/sup 14/C)lyxose followed by oxidative decomposition of the corresponding nitrohexitols yielded /sup 14/C-labelled D-galactose. Described is also the preparation of D-(U-/sup 14/C)arabinose from D-(U-/sup 14/C)glucose and the conversion of D-(U-/sup 14/C)arabinose to D-(U-/sup 14/C)xylose and D-(U-/sup 14/C)lyxose.

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

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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%. Copyright © 2014. Published by Elsevier Ltd.

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].

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

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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.

Influence of nucleotide modifications at the C2' position on the Hoogsteen base-paired parallel-stranded duplex of poly(A) RNA.

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Copp, William; Denisov, Alexey Y; Xie, Jingwei; Noronha, Anne M; Liczner, Christopher; Safaee, Nozhat; Wilds, Christopher J; Gehring, Kalle

2017-09-29

Polyadenylate (poly(A)) has the ability to form a parallel duplex with Hoogsteen adenine:adenine base pairs at low pH or in the presence of ammonium ions. In order to evaluate the potential of this structural motif for nucleic acid-based nanodevices, we characterized the effects on duplex stability of substitutions of the ribose sugar with 2'-deoxyribose, 2'-O-methyl-ribose, 2'-deoxy-2'-fluoro-ribose, arabinose and 2'-deoxy-2'-fluoro-arabinose. Deoxyribose substitutions destabilized the poly(A) duplex both at low pH and in the presence of ammonium ions: no duplex formation could be detected with poly(A) DNA oligomers. Other sugar C2' modifications gave a variety of effects. Arabinose and 2'-deoxy-2'-fluoro-arabinose nucleotides strongly destabilized poly(A) duplex formation. In contrast, 2'-O-methyl and 2'-deoxy-2'-fluoro-ribo modifications were stabilizing either at pH 4 or in the presence of ammonium ions. The differential effect suggests they could be used to design molecules selectively responsive to pH or ammonium ions. To understand the destabilization by deoxyribose, we determined the structures of poly(A) duplexes with a single DNA residue by nuclear magnetic resonance spectroscopy and X-ray crystallography. The structures revealed minor structural perturbations suggesting that the combination of sugar pucker propensity, hydrogen bonding, pKa shifts and changes in hydration determine duplex stability. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

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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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. PMID:26295944

Bioconversion of lignocellulose-derived sugars to ethanol by engineered Saccharomyces cerevisiae.

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Madhavan, Anjali; Srivastava, Aradhana; Kondo, Akihiko; Bisaria, Virendra S

2012-03-01

Lignocellulosic biomass from agricultural and agro-industrial residues represents one of the most important renewable resources that can be utilized for the biological production of ethanol. The yeast Saccharomyces cerevisiae is widely used for the commercial production of bioethanol from sucrose or starch-derived glucose. While glucose and other hexose sugars like galactose and mannose can be fermented to ethanol by S. cerevisiae, the major pentose sugars D-xylose and L-arabinose remain unutilized. Nevertheless, D-xylulose, the keto isomer of xylose, can be fermented slowly by the yeast and thus, the incorporation of functional routes for the conversion of xylose and arabinose to xylulose or xylulose-5-phosphate in Saccharomyces cerevisiae can help to improve the ethanol productivity and make the fermentation process more cost-effective. Other crucial bottlenecks in pentose fermentation include low activity of the pentose phosphate pathway enzymes and competitive inhibition of xylose and arabinose transport into the cell cytoplasm by glucose and other hexose sugars. Along with a brief introduction of the pretreatment of lignocellulose and detoxification of the hydrolysate, this review provides an updated overview of (a) the key steps involved in the uptake and metabolism of the hexose sugars: glucose, galactose, and mannose, together with the pentose sugars: xylose and arabinose, (b) various factors that play a major role in the efficient fermentation of pentose sugars along with hexose sugars, and (c) the approaches used to overcome the metabolic constraints in the production of bioethanol from lignocellulose-derived sugars by developing recombinant S. cerevisiae strains.

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

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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.

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

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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.

Relationship between molecular weight, monosaccharide composition and immunobiologic activity of Astragalus polysaccharides.

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Jiang, Yiping; Qi, Xiaohui; Gao, Kai; Liu, Wenjun; Li, Na; Cheng, Ningbo; Ding, Gang; Huang, Wenzhe; Wang, Zhenzhong; Xiao, Wei

2016-10-01

Four Astragalus polysaccharides (APS1-APS4) were isolated from the water extract of Radix Astragali and purified through ethanol precipitation with 20 %, 40 %, 60 % and 80 % ethanol, respectively. The total sugar content was measured by sulfuric acid-phenol method. Their molecular weight was determined using high performance gel permeation chromatography (HPGPC) and their monosaccharide composition was analyzed by reversed-phase high performance liquid chromatography (HPLC) after pre-column derivatization. Then the immunobiologic activity of APS was evaluated by the experiment of spleen lymphocytes proliferation in vitro. The data suggested that precipitation by different concentration of ethanol will obtain different molecular weight APS, the higher concentration of ethanol the smaller molecular weight for APS. The molecular weights of four APS were 257.7 kDa, 40.1 kDa, 15.3 kDa and 3.2 kDa. Monosaccharide composition analysis indicated that APS1 consisted of glucose only, and APS2 all consisted of arabinose. APS3 consisted of rhamnose, glucose, galactose and arabinose and APS4 consisted of galactose and arabinose, in a molar ratio of 1:10.76:6.55:12 and 3.02:1. The result of immunobiologic activity assay showed that both APS2 and APS3 can effectively stimulate normal spleen lymphocyte proliferation in vitro. Apart from this, the effect of APS2 also showed dose dependent tendency from 6.25 μg/mL to 800 μg/mL. The result of this research indicated that Astragalus polysaccharides, which consist of arabinose and their molecular weight between 15.2 kDa to 40.1 kDa, neither too high nor too low, had significant immune activity.

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

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Rodrussamee, Nadchanok; Lertwattanasakul, Noppon; Hirata, Katsushi; Suprayogi; Limtong, Savitree; Kosaka, Tomoyuki; Yamada, Mamoru

2011-05-01

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.

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.)

Identification of the missing links in prokaryotic pentose oxidation pathways: evidence for enzyme recruitment.

Science.gov (United States)

Brouns, Stan J J; Walther, Jasper; Snijders, Ambrosius P L; van de Werken, Harmen J G; Willemen, Hanneke L D M; Worm, Petra; de Vos, Marjon G J; Andersson, Anders; Lundgren, Magnus; Mazon, Hortense F M; van den Heuvel, Robert H H; Nilsson, Peter; Salmon, Laurent; de Vos, Willem M; Wright, Phillip C; Bernander, Rolf; van der Oost, John

2006-09-15

The pentose metabolism of Archaea is largely unknown. Here, we have employed an integrated genomics approach including DNA microarray and proteomics analyses to elucidate the catabolic pathway for D-arabinose in Sulfolobus solfataricus. During growth on this sugar, a small set of genes appeared to be differentially expressed compared with growth on D-glucose. These genes were heterologously overexpressed in Escherichia coli, and the recombinant proteins were purified and biochemically studied. This showed that D-arabinose is oxidized to 2-oxoglutarate by the consecutive action of a number of previously uncharacterized enzymes, including a D-arabinose dehydrogenase, a D-arabinonate dehydratase, a novel 2-keto-3-deoxy-D-arabinonate dehydratase, and a 2,5-dioxopentanoate dehydrogenase. Promoter analysis of these genes revealed a palindromic sequence upstream of the TATA box, which is likely to be involved in their concerted transcriptional control. Integration of the obtained biochemical data with genomic context analysis strongly suggests the occurrence of pentose oxidation pathways in both Archaea and Bacteria, and predicts the involvement of additional enzyme components. Moreover, it revealed striking genetic similarities between the catabolic pathways for pentoses, hexaric acids, and hydroxyproline degradation, which support the theory of metabolic pathway genesis by enzyme recruitment.

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

Lipolytic and antimicrobial activities of Pseudomonas strains ...

African Journals Online (AJOL)

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Purpose: To identify and determine lipolytic and antimicrobial activities, and antibiotic susceptibility of ... reverse-phase C-18 column high-performance liquid chromatography (HPLC). ..... arabinose, D-cellobiose, D-fructose, D-galactose,.

Recovery of a Burkholderia thailandensis-like isolate from an Australian water source

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Wilkins Patricia P

2008-04-01

Full Text Available Abstract Background Burkholderia thailandensis, a close relative of Burkholderia pseudomallei, has previously been reported only from Southeast Asia and North America. It is biochemically differentiated from B. pseudomallei by the ability to utilize arabinose. During the course of environmental sampling for B. pseudomallei in the Northern Territory of Australia, an isolate, MSMB 43, was recovered that is arabinose positive. Results Genetic analysis using 16S rDNA sequencing and DNA/DNA hybridization indicates that MSMB 43 is most similar to B. thailandensis although multi-locus sequence typing indicates that this isolate is divergent from both B. pseudomallei and other described B. thailandensis. Conclusion We report the isolation and initial characterization of strain MSMB 43, which is a B. thailandensis-like isolate recovered in Australia.

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

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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

Tagatose: properties, applications, and biotechnological processes.

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Oh, Deok-Kun

2007-08-01

D-Tagatose has attracted a great deal of attention in recent years due to its health benefits and similar properties to sucrose. D-Tagatose can be used as a low-calorie sweetener, as an intermediate for synthesis of other optically active compounds, and as an additive in detergent, cosmetic, and pharmaceutical formulation. Biotransformation of D-tagatose has been produced using several biocatalyst sources. Among the biocatalysts, L-arabinose isomerase has been mostly applied for D-tagatose production because of the industrial feasibility for the use of D-galactose as a substrate. In this article, the characterization of many L-arabinose isomerases and their D-tagatose production is compared. Protein engineering and immobilization of the enzyme for increasing the conversion rate of D-galactose to D-tagatose are also reviewed.

Immunomodulatory activity of purified arabinoxylans from finger millet (Eleusine coracana, v. Indaf 15) bran.

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Savitha Prashanth, M R; Shruthi, R R; Muralikrishna, G

2015-09-01

Biological activities of alkali extracted (Barium hydroxide: BE-480 kDa, Potassium hydroxide: KE1-1080 and KE2-40 kDa), purified arabinoxylans (AX) from the finger millet bran varying in their molecular weight, phenolic acid content, arabinose to xylose ratios were evaluated for their immune-stimulatory activities using murine lymphocytes and peritoneal exudate macrophages. All three purified AX displayed significant (p 2 fold) and macrophage phagocytosis than KE1 and KE2. The above results clearly documented that the immunostimulatory activity of arabinoxylans is directly proportional to the amount of ferulic acid content (0.11 mg/100 g), whereas molecular weight as well as arabinose/xylose ratio, did not have any bearing. Purified AX from the finger millet bran can be explored as a potent natural immunomodulator.

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

Bacillus halodurans RecA-DNA binding and RecA- mediated ...

African Journals Online (AJOL)

STORAGESEVER

2009-05-04

May 4, 2009 ... ... University of Ngaoundéré, Faculty of Science, Department of Biological Sciences, P. O. Box 454, ... Kowalczykowski, 1991; Roca and Cox, 1997; Walker, ... plasmid was transformed and overexpressed into the arabinose-.

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...

NCBI nr-aa BLAST: CBRC-DMEL-02-0080 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-DMEL-02-0080 ref|NP_622419.1| Ribose/xylose/arabinose/galactoside ABC-type transport systems...inose/galactoside ABC-type transport systems, permease components [Thermoanaerobacter tengcongensis MB4] NP_622419.1 0.92 33% ...

Identification and characterization of D-xylulokinase from the D-xylose-fermenting fungus, Mucor circinelloides.

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Komeda, Hidenobu; Yamasaki-Yashiki, Shino; Hoshino, Kazuhiro; Asano, Yasuhisa

2014-11-01

D-Xylulokinase catalyzes the phosphorylation of D-xylulose in the final step of the pentose catabolic pathway to form d-xylulose-5-phosphate. The D-xylulokinase activity was found to be induced by both D-xylose and L-arabinose, as well as some of the other enzymes involved in the pentose catabolism, in the D-xylose-fermenting zygomycetous fungus, Mucor circinelloides NBRC 4572. The putative gene, xyl3, which may encode D-xylulokinase, was detected in the genome sequence of this strain. The amino acid sequence deduced from the gene was more similar to D-xylulokinases from an animal origin than from other fungi. The recombinant enzyme was purified from the E. coli transformant expressing xyl3 and then characterized. The ATP-dependent phosphorylative activity of the enzyme was the highest toward D-xylulose. Its kinetic parameters were determined as Km (D-xylulose) = 0.29 mM and Km (ATP) = 0.51 mM, indicating that the xyl3 gene encoded D-xylulokinase (McXK). Western blot analysis revealed that McXK was induced by L-arabinose as well as D-xylose and the induction was repressed in the presence of D-glucose, suggesting that the enzyme may be involved in the catabolism of D-xylose and L-arabinose and is subject to carbon catabolite repression in this fungus. This is the first study on D-xylulokinase from zygomycetous fungi. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

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

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de Castro, María; Miller, Janice G; Acebes, José Luis; Encina, Antonio; García-Angulo, Penélope; Fry, Stephen C

2015-04-01

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 [(3)H]arabinose, and traced the distribution of (3)H-pentose residues between xylans, xyloglucans and other polymers in several cellular compartments for 5 h. Habituated cells were slower taking up exogenous [(3)H]arabinose. Tritium was incorporated into polysaccharide-bound arabinose and xylose residues, but habituated cells diverted a higher proportion of their new [(3)H]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 (3)H-hemicelluloses ([(3)H]xylans and [(3)H]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 arabinoxylans by extra-protoplasmic phenolic cross-linking, as well as xyloglucans, during wall assembly. © 2015 Institute of Botany, Chinese Academy of Sciences.

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

Pseudomonas aeruginosa can develop resistance to polymyxin as a consequence of mutations in the PhoPQ regulatory system, mediated by covalent lipid A modification. Transposon mutagenesis of a polymyxin-resistant phoQ mutant defined 41 novel loci required for resistance, including two regulatory s......, indicate that addition of 4-amino-L-arabinose to lipid A is not the only PhoPQ-regulated biochemical mechanism required for resistance, and demonstrate that colRS and cprS mutations can contribute to high-level clinical resistance....... 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...

In vivo phosphorylation of a peptide tag for protein purification.

Science.gov (United States)

Goux, Marine; Fateh, Amina; Defontaine, Alain; Cinier, Mathieu; Tellier, Charles

2016-05-01

To design a new system for the in vivo phosphorylation of proteins in Escherichia coli using the co-expression of the α-subunit of casein kinase II (CKIIα) and a target protein, (Nanofitin) fused with a phosphorylatable tag. The level of the co-expressed CKIIα was controlled by the arabinose promoter and optimal phosphorylation was obtained with 2 % (w/v) arabinose as inductor. The effectiveness of the phosphorylation system was demonstrated by electrophoretic mobility shift assay (NUT-PAGE) and staining with a specific phosphoprotein-staining gel. The resulting phosphorylated tag was also used to purify the phosphoprotein by immobilized metal affinity chromatography, which relies on the specific interaction of phosphate moieties with Fe(III). The use of a single tag for both the purification and protein array anchoring provides a simple and straightforward system for protein analysis.

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

S gene encoding an arabinose binding protein was characterized using an Sulfolobus islandicus reporter gene system. The minimal active araS promoter (P(araS)) was found to be 59 nucleotides long and harboured four promoter elements: an ara-box, an upstream transcription factor B-responsive element (BRE......), a TATA-box and a proximal promoter element, each of which contained important nucleotides that either greatly decreased or completely abolished promoter activity upon mutagenesis. The basal araS promoter was virtually inactive due to intrinsically weak BRE element, and the upstream activating sequence...... (UAS) ara-box activated the basal promoter by recruiting transcription factor B to its BRE. While this UAS ensured a general expression from an inactive or weak basal promoter in the presence of other tested carbon resources, it exhibited a strong arabinose-responsive transcriptional activation. To our...

Seven gene deletions in seven days

DEFF Research Database (Denmark)

Ingemann Jensen, Sheila; Lennen, Rebecca; Herrgard, Markus

2015-01-01

Generation of multiple genomic alterations is currently a time consuming process. Here, a method was established that enables highly efficient and simultaneous deletion of multiple genes in Escherichia coli. A temperature sensitive plasmid containing arabinose inducible lambda Red recombineering ...

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...

Value addition to lignocellulosics and biomass-derived sugars

Indian Academy of Sciences (India)

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.

Improving lactic acid productivity from wheat straw hydrolysates by membrane integrated repeated batch fermentation under non-sterilized conditions

DEFF Research Database (Denmark)

Zhang, Yuming; Chen, Xiangrong; Qi, Benkun

2014-01-01

to eliminate the sequential utilization of mixed sugar and feedback inhibition during batch fermentation, membrane integrated repeated batch fermentation (MIRB) was used to improve LA productivity. With MIRB, a high cell density was obtained and the simultaneous fermentation of glucose, xylose and arabinose...

Pectic type II arabinogalactans from starfruit (Averrhoa carambola L.).

Science.gov (United States)

Leivas, Carolina Lopes; Iacomini, Marcello; Cordeiro, Lucimara M C

2016-05-15

A structural characterization of polysaccharides from edible tropical fruit named starfruit (Averrhoa carambola L.) was carried out. After the purification steps, two homogeneous fractions were obtained. Fraction 50R was composed of rhamnose, arabinose, galactose and uronic acid in 4.3:56.2:37.4:2M ratio, respectively and fraction 10R was composed of rhamnose, arabinose, galactose and uronic acid in 2.8:65.8:28.5:3M ratio, respectively. Methylation and NMR spectroscopy analyses showed that these fractions are formed by pectic arabinogalactans, which contain (1→3), (1→6) and (1→3,6)-linked Galp units. The side chains have 3-O-, 5-O- and 3,5-di-O-linked α-Araf and nonreducing end-units of α-Araf, Arap, β-Galp and α-GlcpA. These arabinogalactans were linked to type I rhamnogalacturonans. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

Directory of Open Access Journals (Sweden)

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.

Global Microarray Analysis of Carbohydrate Use in Alkaliphilic Hemicellulolytic Bacterium Bacillus sp. N16-5

Science.gov (United States)

Song, Yajian; Xue, Yanfen; Ma, Yanhe

2013-01-01

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. PMID:23326578

Differential blood-brain barrier permeabilities to [14C]sucrose and [3H]inulin after osmotic opening in the rat

International Nuclear Information System (INIS)

Ziylan, Y.Z.; Robinson, P.J.; Rapoport, S.I.

1983-01-01

The blood-brain barrier (B-BB) in 3-month-old rats was opened unilaterally by infusing 1.8 m L(+)arabinose in water into the internal carotid artery through a catheter in the external carotid. Two poorly penetrating uncharged test radiotracers of differing molecular weight and size, [ 14 C]sucrose (340 daltons, radius 5 A) and [ 3 H]inulin (5500 daltons, radius 15 A), were simultaneously injected i.v. in untreated rats, or rats at 1, 30, or 50 min after infusion of hypertonic arabinose solution. Evans-blue solution was injected 5 min prior to osmotic treatment as a visual indicator of barrier integrity. In regions of uninfused control brains, the [ 14 C]sucrose permeability-surface area (PA) product approximated 10(-5) s-1, whereas PA was not measurable for [ 3 H]inulin. In arabinose-infused animals, PA products on the ipsilateral hemisphere for both [ 14 C]sucrose and [ 3 H]inulin were markedly elevated 6 min after infusion, but decreased by 35 and 55 min. In nearly all regions, statistically significant differences were not found between 6-min [ 14 C]sucrose- and [ 3 H]inulin-PA values (P greater than 0.05). However, at 35 and 55 min in most regions, the PA for [ 3 H]inulin was significantly lower (P less than 0.05) than PA for [ 14 C]sucrose. The results indicated that the B-BB closed more rapidly to larger than to smaller molecules after osmotic treatment and were consistent with a pore model for osmotic B-BB opening

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.

Towards integrated biorefinery from dried distillers grains: Selective extraction of pentoses using dilute acid hydrolysis

International Nuclear Information System (INIS)

Fonseca, Dania A.; Lupitskyy, Robert; Timmons, David; Gupta, Mayank; Satyavolu, Jagannadh

2014-01-01

The abundant availability and high level of hemicellulose content make dried distillers grains (DDG) an attractive feedstock for production of pentoses (C5) and conversion of C5 to bioproducts. One target of this work was to produce a C5 extract (hydrolyzate) with high yield and purity with a low concentration of C5 degradation products. A high selectivity towards pentoses was achieved using dilute acid hydrolysis of DDG in a percolation reactor with liquid recirculation. Pretreatment of starting material using screening and ultrasonication resulted in fractional increase of the pentose yield by 42%. A 94% yield of pentoses on the DDG (280.9 g kg −1 ) was obtained. Selective extraction of individual pentoses has been achieved by using a 2-stage hydrolysis process, resulting in arabinose-rich (arabinose 81.5%) and xylose-rich (xylose 85.2%) streams. A broader impact of this work is towards an Integrated Bio-Refinery based on DDG – for production of biofuels, biochemical intermediates, and other bioproducts. - Highlights: • A process for selective extraction of pentoses from DDG was presented as a part of integrated biorefinery approach. • The selectivity for pentoses was high using dilute acid hydrolysis in a percolation reactor with liquid recirculation. • Pretreatment of DDG using screening and ultrasonication resulted in fractional increase of the pentose yield by 42 %. • A 94% yield in pentoses (280.9 g kg −1 of DDG) was obtained. • A 2-stage hydrolysis process, developed to extract individual pentoses, resulted in arabinose and xylose rich streams

Triterpenoidal saponins from the fruits of Gleditsia caspica with proapoptotic properties.

Science.gov (United States)

Shaheen, Usama; Ragab, Ehab A; Abdalla, Ashraf N; Bader, Ammar

2018-01-01

Three previously undescribed oleanane-type triterpenoidal saponins named caspicaosides L-N were isolated from the fruits of Gleditsia caspica Desf. The aglycons of these saponins were echinocystic acid, erythrodiol and 12-oleanene-3,28,30-triol. Caspicaoside L is a bisdesmosidic saponin acylated with two monoterpenic acids. It has a disaccharide moiety made up of glucose and arabinose attached to C-3 and pentasaccharide moiety linked to C-28 made up of one glucose, 2 xyloses, one inner rhamnose and one terminal rhamnose which was acylated with two identical monoterpenic acids. Caspicaoside M is a monodesmosidic saponin with a trisaccharide moiety at C-3 made up of glucose, xylose and arabinose, while caspicaoside N has a disaccharide moiety at C-3 made up of glucose and arabinose. Their structures were determined by extensive 1D and 2D (DQF-COSY, HSQC, TOCSY, 1 H- 13 C-HSQC-TOCSY, HMBC, ROESY, NOESY) NMR, HRESIMS analyses and chemical degradation. The cytotoxicity MTT-based assay showed that caspicaosides M, N and L, respectively, exhibited high cytotoxic activity with IC 50  ≤ 10 μM (72 h) at least against one of the three used cancer cell lines, MCF 7, A2780 and HT 29; and were 2-34 folds selective against the normal fibroblasts (MRC 5). All compounds also induced apoptosis and caused G 2 /M arrest in MCF 7 cells (24 h); thus showing pro-apoptotic properties. Copyright © 2017 Elsevier Ltd. All rights reserved.

Cloning and characterization of arabinoxylan arabinofuranofydrolases-D3 (AXHd3) from Bifidobacterium adolescentis DSM20083

NARCIS (Netherlands)

Broek, van den L.A.M.; Lloyd, R.M.; Beldman, G.; Verdoes, J.C.; McCleary, B.V.; Voragen, A.G.J.

2005-01-01

Arabinoxylan arabinofuranohydrolase-D3 (AXHd3) from Bifidobacterium adolescentis releases only C3-linked arabinose residues from double-substituted xylose residues. A genomic library of B. adolescentis DSM20083 was screened for the presence of the axhD3 gene. Two plasmids were identified containing

21 CFR 172.610 - Arabinogalactan.

Science.gov (United States)

2010-04-01

... Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Gums... water from Western larch wood, having galactose units and arabinose units in the approximate ratio of...

Identification of the missing links in prokaryotic pentose oxidation pathways: evidence for enzyme recruitment

NARCIS (Netherlands)

Brouns, S.J.J.; Walther, J.; Snijders, A.P.; Werken, van de H.J.G.; Willemen, H.L.D.M.; Worm, P.; Vos, de M.G.; Andersson, A.; Lundgren, M.; Mazon, H.F.; Heuvel, van den R.H.H.; Nilsson, P.; Salmon, L.; Vos, de W.M.; Wright, P.C.; Bernander, R.; Oost, van der J.

2006-01-01

The pentose metabolism of Archaea is largely unknown. Here, we have employed an integrated genomics approach including DNA microarray and proteomics analyses to elucidate the catabolic pathway for D-arabinose in Sulfolobus solfataricus. During growth on this sugar, a small set of genes appeared to

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

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...

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

Directory of Open Access Journals (Sweden)

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.

Concurrent metabolism of pentose and hexose sugars by the polyextremophile Alicyclobacillus acidocaldarius

Energy Technology Data Exchange (ETDEWEB)

Lee, Brady D.; Apel, William A.; DeVeaux, Linda C.; Sheridan, Peter P.

2017-08-03

Alicyclobacillus acidocaldarius is a thermoacidophilic bacterium capable of growth on sugars from plant biomass. Carbon catabolite repression (CCR) allows bacteria to focus cellular resources on a sugar that provides efficient growth, but also allows sequential, rather than simultaneous use when more than one sugar is present. The A. acidocaldarius genome encodes all components of CCR, but transporters encoded are multifacilitator superfamily and ATP-binding cassette type transporters, uncommon for CCR. Therefore, global transcriptome analysis of A. acidocaldarius grown on xylose or fructose was performed in chemostats, followed by attempted induction of CCR with glucose or arabinose. A. acidocaldarius grew while simultaneously metabolizing xylose and glucose, xylose and arabinose, and fructose and glucose, indicating CCR did not control carbon metabolism. Microarrays showed down-regulation of genes during growth on one sugar compared to two. Regulation occurred primarily in genes: 1) encoding regulators, 2) encoding enzymes for cell synthesis, and 3) encoding sugar transporters.

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. Copyright © 2012 Elsevier Ltd. All rights reserved.

The Maillard Reaction Reduced the Sensitization of Tropomyosin and Arginine Kinase from Scylla paramamosain, Simultaneously.

Science.gov (United States)

Han, Xin-Yu; Yang, Huang; Rao, Shi-Tao; Liu, Guang-Yu; Hu, Meng-Jun; Zeng, Bin-Chang; Cao, Min-Jie; Liu, Guang-Ming

2018-03-21

The Maillard reaction was established to reduce the sensitization of tropomyosin (TM) and arginine kinase (AK) from Scylla paramamosain, and the mechanism of the attenuated sensitization was investigated. In the present study, the Maillard reaction conditions were optimized for heating at 100 °C for 60 min (pH 8.5) with arabinose. A low level of allergenicity in mice was shown by the levels of allergen-specific antibodies, and more Th1 and less Th2 cells cytokines produced and associated transcription factors with the Maillard reacted allergen (mAllergen). The tolerance potency in mice was demonstrated by the increased ratio of Th1/Th2 cytokines. Moreover, mass spectrometry analysis showed that some key amino acids of IgE-binding epitopes (K 112 , R 125 , R 133 of TM; K 33 , K 118 , R 202 of AK) were modified by the Maillard reaction. The Maillard reaction with arabinose reduced the sensitization of TM and AK, which may be due to the masked epitopes.

In Vitro Evaluation of Biofilm Dispersal as a Therapeutic Strategy To Restore Antimicrobial Efficacy

DEFF Research Database (Denmark)

Roizman, Dan; Vidaillac, Celine; Givskov, Michael

2017-01-01

As a proof-of-concept study, the direct impact of biofilm dispersal on the in vitro efficacy of imipenem and tobramycin was evaluated against 3-day-old biofilms of Pseudomonas aeruginosa. Arabinose induction of biofilm dispersal via activation of the phosphodiesterase YhjH in the P. aeruginosa en...

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African Journals Online (AJOL)

cadewumi

measurement of the Institute of Materia Medica of Chinese Academy of Medical Sciences, Radix ranunculus ternati contains 16% of sugar, 1.2% of oil, and very little plant alkaloids (Yang et al., 1998). Japanese scholars have separated and identified monosaccharide constituents such as glucose, arabinose and galactose ...

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...

The influence of different cultivation conditions on the metabolome of Fusarium oxysporum.

Science.gov (United States)

Panagiotou, Gianni; Christakopoulos, Paul; Olsson, Lisbeth

2005-08-22

The two most widespread pentose sugars found in the biosphere are d-xylose and l-arabinose. They are both potential substrates for ethanol production. The purpose of this study was to better understand the redox constraints imposed to Fusarium oxysporum during utilization of pentoses. In order to increase ethanol yield and decrease by-product formation, nitrate was used as nitrogen source. The use of NADH, the cofactor in denitrification process when using nitrate as a nitrogen source, improved the ethanol yield on xylose to 0.89 mol mol(-1) compared to the ethanol yield achieved using ammonium as nitrogen source 0.44 mol mol(-1). The improved ethanol yield was followed by a 28% decrease in yield of the by-product xylitol. In order to investigate the metabolic pathway of arabinose and the metabolic limitations for the efficient ethanol production from this sugar, the extracellular and intracellular metabolite profiles were determined under aerobic and anaerobic cultivation conditions. The results of this study clearly show difficulties in channelling of glucose-1-P (G1P) to pentose phosphate pathway (PPP) and reduced NADPH regeneration, suggesting that NADPH becomes a limiting factor for arabinose conversion, resulting in excessive acetate production. Variations of the fungus intracellular amino and non-amino acid pool, under different culture conditions, were evaluated using principal component analysis (PCA). PCA projection of the metabolome data collected from F. oxysporum subjected to environmental perturbations succeeded to visualize different physiological states and the conclusions of this study were that the metabolite profile is unique according to: (1) the carbon source and (2) the oxygen supply, and to a lesser extent to the cultivation phase.

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

Synthesis of arabinoxylan fragments

DEFF Research Database (Denmark)

Underlin, Emilie Nørmølle; Böhm, Maximilian F.; Madsen, Robert

, or production of commercial chemicals which are mainly obtained from fossil fuels today.The arbinoxylan fragments have a backbone of β-1,4-linked xylans with α-L-arabinose units attached at specific positions. The synthesis ultilises an efficient synthetic route, where all the xylan units can be derived from D...

Degradation of differently substituted xylogalacturonans by endoxylogalacturonan hydrolase and endopolygalacturonases.

NARCIS (Netherlands)

Beldman, G.; Vincken, J.P.; Schols, H.A.; Meeuwsen, P.J.A.; Herweijer, M.A.; Voragen, A.G.J.

2003-01-01

A method was developed to make xylogalacturonans (XGAs) with different degrees of xylosylation from gum tragacanth (XGA-25, XGA-29, XGA-35 and XGA-47), using alkali treatment at 4degreesC and acid treatment at 100degreesC. Ester linkages as well as fucose and arabinose substituents could selectively

Rodentibacter gen. nov including Rodentibacter pneumotropicus comb. nov., Rodentibacter heylii sp nov., Rodentibacter myodis sp nov., Rodentibacter ratti sp nov., Rodentibacter heidelbergensis sp nov., Rodentibacter trehalosifermentans sp nov., Rodentibacter rarus sp nov., Rodentibacter mrazii and two genomospecies

DEFF Research Database (Denmark)

Adhikary, Sadhana; Nicklas, Werner; Bisgaard, Magne

2017-01-01

-galactosidase and in acid formation from (+)-l-arabinose, (−)-d-ribose, (+)-d-xylose, myo-inositol, (−)-d-mannitol, lactose, melibiose and trehalose. Forty-six strains including taxon 48 of Bisgaard formed a monophyletic group by rpoB and 16S rRNA gene sequence analysis, but could not be separated phenotypically from R...

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 K m =16.1 mM and k cat /K m =67.0 min -1 mM -1 , while l-arabitol was also a substrate for the enzyme with K m =31.1 mM and k cat /K m =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. Copyright © 2016 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Stoichiometry and kinetics of single and mixed substrate uptake in Aspergillus niger.

Science.gov (United States)

Lameiras, Francisca; Ras, Cor; Ten Pierick, Angela; Heijnen, Joseph J; van Gulik, Walter M

2018-02-01

In its natural environment, the filamentous fungus Aspergillus niger grows on decaying fruits and plant material, thereby enzymatically degrading the lignocellulosic constituents (lignin, cellulose, hemicellulose, and pectin) into a mixture of mono- and oligosaccharides. To investigate the kinetics and stoichiometry of growth of this fungus on lignocellulosic sugars, we carried out batch cultivations on six representative monosaccharides (glucose, xylose, mannose, rhamnose, arabinose, and galacturonic acid) and a mixture of these. Growth on these substrates was characterized in terms of biomass yields, oxygen/biomass ratios, and specific conversion rates. Interestingly, in combination, some of the carbon sources were consumed simultaneously and some sequentially. With a previously developed protocol, a sequential chemostat cultivation experiment was performed on a feed mixture of the six substrates. We found that the uptake of glucose, xylose, and mannose could be described with a Michaelis-Menten-type kinetics; however, these carbon sources seem to be competing for the same transport systems, while the uptake of arabinose, galacturonic acid, and rhamnose appeared to be repressed by the presence of other substrates.

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

Directory of Open Access Journals (Sweden)

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.

Arabinoxylan from finger millet (Eleusine coracana, v. Indaf 15) bran: purification and characterization.

Science.gov (United States)

Savitha Prashanth, M R; Muralikrishna, G

2014-01-01

Water unextractable portion from finger millet bran was sequentially extracted with saturated barium hydroxide (BE) and 1M potassium hydroxide (KE) solutions. They consisted preponderantly of arabinose and xylose in different ratios. Ferulic, caffeic, coumaric and vanillic acids were identified as major bound phenolic acids. BE and KE were purified on DEAE-cellulose column by eluting successively with different eluants. The major fractions (0.1 M ammonium carbonate) were resolved into one (BE) and two subfractions (KE1 and KE2) respectively on Sephacryl S-400 gel filtration chromatography and their homogeneity was ascertained by gel filtration, cellulose acetate membrane electrophoresis and capillary electrophoresis. The average molecular weight of BE, KE1 and KE2 were found to be 430, 1028 and 40 kDa respectively. The structural elucidation of the purified polysaccharides by (1)H and (13)C NMR analysis indicated the backbone to be 1,4-β-D-linked xylan with substitution mainly at O-2 or O-3 and/or both by α-l-arabinose residues. Copyright © 2013 Elsevier Ltd. All rights reserved.

Purification, characterization and immunomodulatory activity of polysaccharides from stem lettuce.

Science.gov (United States)

Nie, Chenzhipeng; Zhu, Peilei; Ma, Shuping; Wang, Mingchun; Hu, Youdong

2018-05-15

Stem lettuce has a long history of cultivation in China and possesses high nutritional and medicinal value. In our previous studies, extraction optimization, characterization, and bioactivities of stem lettuce polysaccharides (SLP) were investigated. In this study, SLP were further separated into two purified polysaccharides, SLP-1 and SLP-2, by anion exchange chromatography followed by size exclusion chromatography. SLP-1, with a molecular weight of 90 KDa, was mainly composed of galacturonic acid, galactose and arabinose in a molar ratio of 17.6:41.7:33.9. SLP-2, with a molecular weight of 44 KDa, was mainly composed of mannose, galacturonic acid, galactose and arabinose in a molar ratio of 11.5:69.5:9.3:8.2. In addition, both purified polysaccharides contain sulphate radicals, have triple helical structures and can promote macrophage proliferation without cytotoxicity. SLP-2 was better able to stimulate phagocytic and nitric oxide production than SLP-1. The results suggest that polysaccharides from stem lettuce could be explored as immunomodulatory agents in the field of pharmaceuticals and functional foods. Copyright © 2018 Elsevier Ltd. All rights reserved.

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. Copyright © 2012 Elsevier B.V. All rights reserved.

Efficient Extracellular Expression of Metalloprotease for Z-Aspartame Synthesis.

Science.gov (United States)

Zhu, Fucheng; Liu, Feng; Wu, Bin; He, Bingfang

2016-12-28

Metalloprotease PT121 and its mutant Y114S (Tyr114 was substituted to Ser) are effective catalysts for the synthesis of Z-aspartame (Z-APM). This study presents the selection of a suitable signal peptide for improving expression and extracellular secretion of proteases PT121 and Y114S by Escherichia coli. Co-inducers containing IPTG and arabinose were used to promote protease production and cell growth. Under optimal conditions, the expression levels of PT121 and Y114S reached >500 mg/L, and the extracellular activity of PT121/Y114S accounted for 87/82% of the total activity of proteases. Surprisingly, purer protein was obtained in the supernatant, because arabinose reduced cell membrane permeability, avoiding cell lysis. Comparison of Z-APM synthesis and caseinolysis between proteases PT121 and Y114S showed that mutant Y114S presented remarkably higher activity of Z-APM synthesis and considerably lower activity of caseinolysis. The significant difference in substrate specificity renders these enzymes promising biocatalysts.

Box-Behnken design for extraction optimization, characterization and in vitro antioxidant activity of Cicer arietinum L. hull polysaccharides.

Science.gov (United States)

Ye, Zipeng; Wang, Wei; Yuan, Qingxia; Ye, Hong; Sun, Yi; Zhang, Hongcheng; Zeng, Xiaoxiong

2016-08-20

The optimal extraction conditions with a yield of 5.37±0.15% for extraction of polysaccharides from chickpea (Cicer arietinum L.) hull (CHPS) were determined as extraction temperature 99°C, extraction time 2.8h and ratio of water to raw material 24mL/g. Three fractions of CHPS-1, CHPS-2 and CHPS-3, with average molecular weight of 3.1×10(6), 1.5×10(6) and 7.8×10(5)Da, respectively, were obtained from crude CHPS by chromatography of DEAE Fast Flow and Sephadex G-100. CHPS-1 was composed of mannose, rhamnose, galactose, galacturonic acid, glucose and arabinose, CHPS-2 was composed of mannose, rhamnose, galacturonic acid, galactose, xylose and arabinose, CHPS-3 was composed of galacturonic acid, galactose and rhamnose. CHPS-3 showed the strongest reducing power and protective effect on H2O2-induced oxidative injury in PC12 cells and highest scavenging activities against DPPH and ABTS radicals, while CHPS-2 showed the highest scavenging activity against superoxide anion radical. Copyright © 2016 Elsevier Ltd. All rights reserved.

Thermoanaerobacter pentosaceus sp. nov., an anaerobic, extreme thermophilic, high ethanol-yielding bacterium isolated from household waste

DEFF Research Database (Denmark)

Tomás, Ana Faria; Karakashev, Dimitar Borisov; Angelidaki, Irini

2013-01-01

of approximately 0.5 µm. Optimal growth occurred at 70 °C and pH(25°C) 7, with a maximum growth rate of 0.1 h-1. DNA G+C content was 34.2 mol %. Strain DTU01(T) could ferment arabinose, cellobiose, fructose, galactose, glucose, inulin, lactose, mannose, melibiose, pectin, starch, sucrose, xylan, yeast extract...

Characterization of gums from local acacia species for the food and ...

African Journals Online (AJOL)

It was confirmed from the sugar reactions that their sugar composition were Rhamnose, Arabinose, Galactose, and Glucuronic acid. The viscosities increased with concentration and decreased with time, rose with pH till a pH of about 5 and then fell as the pH increased from 6 to 14. The local gums can be used as suitable ...

Effect of temperature and hydraulic retention time on hydrogen producing granules: Homoacetogenesis and morphological characteristics

International Nuclear Information System (INIS)

Abreu, A. A.; Danko, A. S.; Alves, M. M.

2009-01-01

The effect of temperature and hydraulic retention time (HRT) on the homoacetogenesisi and on the morphological characteristics of hydrogen producing granules was investigated. Hydrogen was produced using an expanded granular sludge blanket (EGSB) reactor, fed with glucose and L-arabinose, under mesophilic (37 degree centigrade), thermophilic (55 degree centigrade), and hyper thermophilic (70 degree centigrade) conditions. (Author)

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.

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

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

UsesIntermediatesBiomass Feedstocks Sugars Glucose Fructose Xylose Arabinose Lactose Sucrose Starch Starch Cellulose Lignin Oil Protein Hemicellulose...these goals, the Program supports the integrated biorefinery, a processing facility that extracts carbohydrates, oils, lignin , and other materials from...biomass, converts them into multiple products including fuels and high value chemicals and materials. Already today, corn wet and dry mills, and

Positron emission tomography probe to monitor selected sugar metabolism in vivo

Science.gov (United States)

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.

Changes in kenaf properties and chemistry as a function of growing time

Science.gov (United States)

Roger M. Rowell; James S. Han

1999-01-01

Kenaf Tainung 1 cultivar was grown in Madison, WI in 1994. The ratio of core to bast fiber, total plant yield, protein, ash, fiber length, extractives, lignin, and sugar content were determined as a function of growing age. Ash, protein, extractives, L-arabinose, L-rhamnose, D-galactose, and D-mannose contents decreased while lignin, D-glucose and D-xylose content...

Turnover of galactans and other cell wall polysaccharides during development of flax plants

International Nuclear Information System (INIS)

Gorshkova, T.A.; Chemikosova, S.B.; Lozovaya, V.V.; Carpita, N.C.

1997-01-01

We investigated the synthesis and turnover of cell wall polysaccharides of the flax (Linum usitatissimum L.) plant during development of the phloem fibers. One-month-old flax plants were exposed to a 40-min pulse with 14CO2 followed by 8-h, 24-h, and 1-month periods of chase with ambient CO2, and radioactivity in cell wall sugars was determined in various plant parts. The relative radioactivity of glucose in noncellulosic polysaccharides was the highest compared with all other cell wall sugars immediately after the pulse and decreased substantially during the subsequent chase. The relative radioactivities of the other cell wall sugars changed with differing rates, indicating turnover of specific polysaccharides. Notably, after 1 month of chase there was a marked decrease in the proportional mass and total radioactivity in cell wall galactose, indicating a long-term turnover of the galactans enriched in the fiber-containing tissues. The ratio of radiolabeled xylose to arabinose also increased during the chase, indicating a turnover of arabinose-containing polymers and interconversion to xylose. The pattern of label redistribution differed between organs, indicating that the cell wall turnover processes are tissue- and cell-specific

Changes in alpha-L-arabinofuranosidase activity in peel and pulp of banana (Musa sp.) fruits during ripening and softening.

Science.gov (United States)

Zhuang, Jun-Ping; Su, Jing; Li, Xue-Ping; Chen, Wei-Xin

2007-04-01

Arabinose is one of the most dynamic cell wall glycosyl residues released during fruit ripening, alpha-L-arabinofuranosidase (alpha-Arab) are major glycosidases that may remove arabinose units from fruit cell wall polysaccharides. To find out whether alpha-Arab plays important roles in banana fruit softening, the enzyme activities in peel and pulp, fruit firmness, respiration rate and ethylene release rate were assayed during banana softening. The results showed that alpha-Arab activities in banana pulp and peel increased slightly at the beginning of storage and reached their maxima when the fruit firmness decreased drastically, alpha-Arab activity increased by more than ten folds in both pulp and peel during ripening and alpha-Arab activities were higher in pulp than in peel. Treatment of banana fruits with ethylene absorbent postponed the time of reaching of its maxima of respiration and ethylene, enhanced the firmness of pup and decreased alpha-Arab activity in the peel and pulp. These results suggest that alpha-Arab induced the decrease of fruit firmness and played an important role in banana fruit softening, and its activity was regulated by ethylene.

Glycoprotein of the wall of sycamore tissue-culture cells.

Science.gov (United States)

Heath, M F; Northcote, D H

1971-12-01

1. A glycoprotein containing a large amount of hydroxyproline is present in the cell walls of sycamore callus cells. This protein is insoluble and remained in the alpha-cellulose when a mild separation procedure was used to obtain the polysaccharide fractions of the wall. The glycoprotein contained a high proportion of arabinose and galactose. 2. Soluble glycopeptides were prepared from the alpha-cellulose fraction when peptide bonds were broken by hydrazinolysis. The soluble material was fractionated by gel filtration and one glycopeptide was further purified by electrophoresis; it had a composition of 10% hydroxyproline, 35% arabinose and 55% galactose, and each hydroxyproline residue carried a glycosyl radical so that the oligosaccharides on the glycopeptide had an average degree of polymerization of 9. 3. The extraction of the glycopeptides was achieved without cleavage of glycosyl bonds, so that the glycoprotein cannot act as a covalent cross-link between the major polysaccharides of the wall. 4. The wall protein approximates in conformation to polyhydroxyproline and therefore it probably has similar physicochemical properties to polyhydroxyproline. This is discussed in relation to the function of the glycoprotein and its effect on the physical and chemical nature of the wall.

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. Copyright © 2016 Elsevier Ltd. All rights reserved.

Anti-fatigue activity of polysaccharide fractions from Lepidium meyenii Walp. (maca).

Science.gov (United States)

Li, Jing; Sun, Qingrui; Meng, Qingran; Wang, Lei; Xiong, Wentao; Zhang, Lianfu

2017-02-01

The two fractions of polysaccharide MPS-1 and MPS-2 were extracted from Lepidium meyenii Walp. (maca) by water, and purified using a DEAE-52 and a Sephadex G-100 column. The molecular weight (M W ) of MPS-1 was 7.6kDa, and the M W of MPS-2 was 6.7kDa. The MPS-1 was composed of xylose, arabinose, galactose and glucose, with the mole ratio 1:1.7:3.3:30.5; the MPS-2 was composed of arabinose, galactose and glucose, with the mole ratio 1:1.3:36.8. The IR spectrum implied that only α-pyranose existed in MPS-1, and both α-pyranose and β-pyranose existed in MPS-2. The anti-fatigue activities of MPS-1 and MPS-2 were measured by the forced swimming test, along with the determination of blood lactate (BLA), urea nitrogen (BUN), lactic dehydrogenase (LDH) activity and liver glycogen (LG). The results indicated that both MPS-1 and MPS-2 presented dose-dependently positive effects on the fatigue related parameters. Additionally, MPS-2 has a better anti-fatigue effect than MPS-1. Copyright © 2016 Elsevier B.V. All rights reserved.

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

2014-01-01

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.

Tunable recombinant protein expression with E. coli in a mixed-feed environment.

Science.gov (United States)

Sagmeister, Patrick; Schimek, Clemens; Meitz, Andrea; Herwig, Christoph; Spadiut, Oliver

2014-04-01

Controlling the recombinant protein production rate in Escherichia coli is of utmost importance to ensure product quality and quantity. Up to now, only the genetic construct, introduced into E. coli, and the specific growth rate of the culture were used to influence and stir the productivity. However, bioprocess technological means to control or even tune the productivity of E. coli are scarce. Here, we present a novel method for the process-technological control over the recombinant protein expression rate in E. coli. A mixed-feed fed-batch bioprocess based on the araBAD promoter expression system using both D-glucose and L-arabinose as assimilable C-sources was designed. Using the model product green fluorescent protein, we show that the specific product formation rate can be efficiently tuned even on the cellular level only via the uptake rate of L-arabinose. This novel approach introduces an additional degree of freedom for the design of recombinant bioprocesses with E. coli. We anticipate that the presented method will result in significant quality and robustness improvement as well as cost and process time reduction for recombinant bacterial bioprocesses in the future.

In vitro fermentation of mulberry fruit polysaccharides by human fecal inocula and impact on microbiota.

Science.gov (United States)

Chen, Chun; Huang, Qiang; Fu, Xiong; Liu, Rui Hai

2016-11-09

This study investigated the in vitro fermentation of polysaccharides from Morus alba L., the contribution of its carbohydrates to the fermentation, and the effect on the composition of gut microbiota. Over 48 h of fermentation, the pH value in the fecal culture decreased from 7.12 to 6.14, and the total short chain fatty acids (SCFA) and acetic, propionic, and butyric acids all significantly increased. After 48 h of fermentation, 45.36 ± 1.36% of the total carbohydrates in the polysaccharide, including 35.72 ± 1.51% of arabinose, 23.1 ± 1.19% of galactose, 41.43 ± 1.52% of glucose, 26.36 ± 1.93% of rhamnose and 65.57 ± 1.07% of galacturic acid, were consumed. The increase in acetic and butyric acids was primarily due to the fermentation of galactose and galacturonic acid in the polysaccharide, while the increase in propionic acid resulted mainly from the fermentation of arabinose and glucose. In addition, the polysaccharide could modulate the gut microbiota composition by increasing the Bacteroidetes population and decreasing the Firmicutes population. The results may facilitate the development of food products known as prebiotics, aimed at improving gastrointestinal health.

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

Differential sensitivity of polyhydroxyalkanoate producing bacteria to fermentation inhibitors and comparison of polyhydroxybutyrate production from Burkholderia cepacia and Pseudomonas pseudoflava

OpenAIRE

Dietrich, Diane; Illman, Barbara; Crooks, Casey

2013-01-01

Background The aim of this study is determine the relative sensitivity of a panel of seven polyhydroxyalkanoate producing bacteria to a panel of seven lignocellulosic-derived fermentation inhibitors representing aliphatic acids, furans and phenolics. A further aim was to measure the polyhydroxybutyrate production of select organisms on lignocellulosic-derived monosaccharides arabinose, xylose, glucose and mannose. Findings We examined the sensitivity of seven polyhydroxyalkanoate producing ba...

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

Science.gov (United States)

Karasov, William H; Caviedes-Vidal, Enrique; Bakken, Bradley Hartman; Izhaki, Ido; Samuni-Blank, Michal; Arad, Zeev

2012-01-01

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) (Pbirds 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 demands placed on them to eliminate concomitantly absorbed SMs.

Differential expression of α-L-arabinofuranosidases during maize (Zea mays L.) root elongation.

Science.gov (United States)

Kozlova, Liudmila V; Gorshkov, Oleg V; Mokshina, Natalia E; Gorshkova, Tatyana A

2015-05-01

Specific α- l -arabinofuranosidases are involved in the realisation of elongation growth process in cells with type II cell walls. Elongation growth in a plant cell is largely based on modification of the cell wall. In type II cell walls, the Ara/Xyl ratio is known to decrease during elongation due to the partial removal of Ara residues from glucuronoarabinoxylan. We searched within the maize genome for the genes of all predicted α-L-arabinofuranosidases that may be responsible for such a process and related their expression to the activity of the enzyme and the amount of free arabinose measured in six zones of a growing maize root. Eight genes of the GH51 family (ZmaABFs) and one gene of the GH3 family (ZmaARA-I) were identified. The abundance of ZmaABF1 and 3-6 transcripts was highly correlated with the measured enzymatic activity and free arabinose content that significantly increased during elongation. The transcript abundances also coincided with the pattern of changes in the Ara/Xyl ratio of the xylanase-extractable glucuronoarabinoxylan described in previous studies. The expression of ZmaABF3, 5 and 6 was especially up-regulated during elongation although corresponding proteins are devoid of the catalytic glutamate at the proper position. ZmaABF2 transcripts were specifically enriched in the root cap and meristem. A single ZmaARA-I gene was not expressed as a whole gene but instead as splice variants that encode the C-terminal end of the protein. Changes in the ZmaARA-I transcript level were rather moderate and had no significant correlation with free arabinose content. Thus, elongation growth of cells with type II cell walls is accompanied by the up-regulation of specific and predicted α-L-arabinofuranosidase genes, and the corresponding activity is indeed pronounced and is important for the modification of glucuronoarabinoxylan, which plays a key role in the modification of the cell wall supramolecular organisation.

A Pyranose-2-Phosphate Motif Is Responsible for Both Antibiotic Import and Quorum-Sensing Regulation in Agrobacterium tumefaciens.

Directory of Open Access Journals (Sweden)

Abbas El Sahili

2015-08-01

Full Text Available Periplasmic binding proteins (PBPs in association with ABC transporters select and import a wide variety of ligands into bacterial cytoplasm. They can also take up toxic molecules, as observed in the case of the phytopathogen Agrobacterium tumefaciens strain C58. This organism contains a PBP called AccA that mediates the import of the antibiotic agrocin 84, as well as the opine agrocinopine A that acts as both a nutrient and a signalling molecule for the dissemination of virulence genes through quorum-sensing. Here, we characterized the binding mode of AccA using purified agrocin 84 and synthetic agrocinopine A by X-ray crystallography at very high resolution and performed affinity measurements. Structural and affinity analyses revealed that AccA recognizes an uncommon and specific motif, a pyranose-2-phosphate moiety which is present in both imported molecules via the L-arabinopyranose moiety in agrocinopine A and the D-glucopyranose moiety in agrocin 84. We hypothesized that AccA is a gateway allowing the import of any compound possessing a pyranose-2-phosphate motif at one end. This was structurally and functionally confirmed by experiments using four synthetic compounds: agrocinopine 3'-O-benzoate, L-arabinose-2-isopropylphosphate, L-arabinose-2-phosphate and D-glucose-2-phosphate. By combining affinity measurements and in vivo assays, we demonstrated that both L-arabinose-2-phosphate and D-glucose-2-phosphate, which are the AccF mediated degradation products of agrocinopine A and agrocin 84 respectively, interact with the master transcriptional regulator AccR and activate the quorum-sensing signal synthesis and Ti plasmid transfer in A. tumefaciens C58. Our findings shed light on the role of agrocinopine and antibiotic agrocin 84 on quorum-sensing regulation in A. tumefaciens and reveal how the PBP AccA acts as vehicle for the importation of both molecules by means of a key-recognition motif. It also opens future possibilities for the

A Pyranose-2-Phosphate Motif Is Responsible for Both Antibiotic Import and Quorum-Sensing Regulation in Agrobacterium tumefaciens.

Science.gov (United States)

El Sahili, Abbas; Li, Si-Zhe; Lang, Julien; Virus, Cornelia; Planamente, Sara; Ahmar, Mohammed; Guimaraes, Beatriz G; Aumont-Nicaise, Magali; Vigouroux, Armelle; Soulère, Laurent; Reader, John; Queneau, Yves; Faure, Denis; Moréra, Solange

2015-08-01

Periplasmic binding proteins (PBPs) in association with ABC transporters select and import a wide variety of ligands into bacterial cytoplasm. They can also take up toxic molecules, as observed in the case of the phytopathogen Agrobacterium tumefaciens strain C58. This organism contains a PBP called AccA that mediates the import of the antibiotic agrocin 84, as well as the opine agrocinopine A that acts as both a nutrient and a signalling molecule for the dissemination of virulence genes through quorum-sensing. Here, we characterized the binding mode of AccA using purified agrocin 84 and synthetic agrocinopine A by X-ray crystallography at very high resolution and performed affinity measurements. Structural and affinity analyses revealed that AccA recognizes an uncommon and specific motif, a pyranose-2-phosphate moiety which is present in both imported molecules via the L-arabinopyranose moiety in agrocinopine A and the D-glucopyranose moiety in agrocin 84. We hypothesized that AccA is a gateway allowing the import of any compound possessing a pyranose-2-phosphate motif at one end. This was structurally and functionally confirmed by experiments using four synthetic compounds: agrocinopine 3'-O-benzoate, L-arabinose-2-isopropylphosphate, L-arabinose-2-phosphate and D-glucose-2-phosphate. By combining affinity measurements and in vivo assays, we demonstrated that both L-arabinose-2-phosphate and D-glucose-2-phosphate, which are the AccF mediated degradation products of agrocinopine A and agrocin 84 respectively, interact with the master transcriptional regulator AccR and activate the quorum-sensing signal synthesis and Ti plasmid transfer in A. tumefaciens C58. Our findings shed light on the role of agrocinopine and antibiotic agrocin 84 on quorum-sensing regulation in A. tumefaciens and reveal how the PBP AccA acts as vehicle for the importation of both molecules by means of a key-recognition motif. It also opens future possibilities for the rational design of

Plant-based foods containing cell wall polysaccharides rich in specific active monosaccharides protect against myocardial injury in rat myocardial infarction models.

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Lim, Sun Ha; Kim, Yaesil; Yun, Ki Na; Kim, Jin Young; Jang, Jung-Hee; Han, Mee-Jung; Lee, Jongwon

2016-12-08

Many cohort studies have shown that consumption of diets containing a higher composition of foods derived from plants reduces mortality from coronary heart disease (CHD). Here, we examined the active components of a plant-based diet and the underlying mechanisms that reduce the risk of CHD using three rat models and a quantitative proteomics approach. In a short-term myocardial infarction (MI) model, intake of wheat extract (WE), the representative cardioprotectant identified by screening approximately 4,000 samples, reduced myocardial injury by inhibiting apoptosis, enhancing ATP production, and maintaining protein homeostasis. In long-term post-MI models, this myocardial protection resulted in ameliorating adverse left-ventricular remodelling, which is a predictor of heart failure. Among the wheat components, arabinose and xylose were identified as active components responsible for the observed efficacy of WE, which was administered via ingestion and tail-vein injections. Finally, the food components of plant-based diets that contained cell wall polysaccharides rich in arabinose, xylose, and possibly fucose were found to confer protection against myocardial injury. These results show for the first time that specific monosaccharides found in the cell wall polysaccharides in plant-based diets can act as active ingredients that reduce CHD by inhibiting postocclusion steps, including MI and heart failure.

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.

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

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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.

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

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Samia Khan

2003-01-01

Full Text Available 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 regulated the specific growth and β-galactosidase production rates. Lactose (2 % supported the maximum specific product yield (YP/X, followed by galactose, sucrose, cellobiose, xylose, arabinose and glucose. Its synthesis was regulated by an induction and a growth-dependent repression mechanism. The optimum temperature for the production was found to be 35–37 °C. The highest volumetric productivity of enzyme (80.0 IU/L/h occurred on lactose-corn steep liquor medium. This was significantly higher than the calculated values reported in the literature. Thermodynamic studies revealed that the cells provided a defence mechanism against thermal inactivation. The enzyme was stable at 60 °C and pH=5.0–7.0, and it may find application in commercial lactose hydrolysis.

Immobilized Trienzymatic System with Enhanced Stabilization for the Biotransformation of Lactose

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Pedro Torres

2017-02-01

Full Text Available The use of ketohexose isomerases is a powerful tool in lactose whey processing, but these enzymes can be very sensitive and expensive. Development of immobilized/stabilized biocatalysts could be a further option to improve the process. In this work, β-galactosidase from Bacillus circulans, l-arabinose (d-galactose isomerase from Enterococcus faecium, and d-xylose (d-glucose isomerase from Streptomyces rubiginosus were immobilized individually onto Eupergit C and Eupergit C 250 L. Immobilized activity yields were over 90% in all cases. With the purpose of increasing thermostability of derivatives, two post-immobilization treatments were performed: alkaline incubation to favor the formation of additional covalent linkages, and blocking of excess oxirane groups by reacting with glycine. The greatest thermostability was achieved when alkaline incubation was carried out for 24 h, producing l-arabinose isomerase-Eupergit C derivatives with a half-life of 379 h and d-xylose isomerase-Eupergit C derivatives with a half-life of 554 h at 50 °C. Preliminary assays using immobilized and stabilized biocatalysts sequentially to biotransform lactose at pH 7.0 and 50 °C demonstrated improved performances as compared with soluble enzymes. Further improvements in ketohexose productivities were achieved when the three single-immobilizates were incubated simultaneously with lactose in a mono-reactor system.

Differential Selectivity of the Escherichia coli Cell Membrane Shifts the Equilibrium for the Enzyme-Catalyzed Isomerization of Galactose to Tagatose▿

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Kim, Jin-Ha; Lim, Byung-Chul; Yeom, Soo-Jin; Kim, Yeong-Su; Kim, Hye-Jung; Lee, Jung-Kul; Lee, Sook-Hee; Kim, Seon-Won; Oh, Deok-Kun

2008-01-01

An Escherichia coli galactose kinase gene knockout (ΔgalK) strain, which contains the l-arabinose isomerase gene (araA) to isomerize d-galactose to d-tagatose, showed a high conversion yield of tagatose compared with the original galK strain because galactose was not metabolized by endogenous galactose kinase. In whole cells of the ΔgalK strain, the isomerase-catalyzed reaction exhibited an equilibrium shift toward tagatose, producing a tagatose fraction of 68% at 37°C, whereas the purified l-arabinose isomerase gave a tagatose equilibrium fraction of 36%. These equilibrium fractions are close to those predicted from the measured equilibrium constants of the isomerization reaction catalyzed in whole cells and by the purified enzyme. The equilibrium shift in these cells resulted from the higher uptake and lower release rates for galactose, which is a common sugar substrate, than for tagatose, which is a rare sugar product. A ΔmglB mutant had decreased uptake rates for galactose and tagatose, indicating that a methylgalactoside transport system, MglABC, is the primary contributing transporter for the sugars. In the present study, whole-cell conversion using differential selectivity of the cell membrane was proposed as a method for shifting the equilibrium in sugar isomerization reactions. PMID:18263746

Differential selectivity of the Escherichia coli cell membrane shifts the equilibrium for the enzyme-catalyzed isomerization of galactose to tagatose.

Science.gov (United States)

Kim, Jin-Ha; Lim, Byung-Chul; Yeom, Soo-Jin; Kim, Yeong-Su; Kim, Hye-Jung; Lee, Jung-Kul; Lee, Sook-Hee; Kim, Seon-Won; Oh, Deok-Kun

2008-04-01

An Escherichia coli galactose kinase gene knockout (DeltagalK) strain, which contains the l-arabinose isomerase gene (araA) to isomerize d-galactose to d-tagatose, showed a high conversion yield of tagatose compared with the original galK strain because galactose was not metabolized by endogenous galactose kinase. In whole cells of the DeltagalK strain, the isomerase-catalyzed reaction exhibited an equilibrium shift toward tagatose, producing a tagatose fraction of 68% at 37 degrees C, whereas the purified l-arabinose isomerase gave a tagatose equilibrium fraction of 36%. These equilibrium fractions are close to those predicted from the measured equilibrium constants of the isomerization reaction catalyzed in whole cells and by the purified enzyme. The equilibrium shift in these cells resulted from the higher uptake and lower release rates for galactose, which is a common sugar substrate, than for tagatose, which is a rare sugar product. A DeltamglB mutant had decreased uptake rates for galactose and tagatose, indicating that a methylgalactoside transport system, MglABC, is the primary contributing transporter for the sugars. In the present study, whole-cell conversion using differential selectivity of the cell membrane was proposed as a method for shifting the equilibrium in sugar isomerization reactions.

Real-time PCR analysis of carbon catabolite repression of cellobiose gene transcription in Trametes versicolor

Energy Technology Data Exchange (ETDEWEB)

Stapleton, P. C.; O' Mahoney, J.; Dobson, A. D. W. [National University of Ireland, Microbiology Department, Cork (Ireland)

2004-02-01

Previous reports indicate that in white rot fungi such as Trametes versicolor, the production of cellobiose dehydrogenase (CDH), an extracellular haemo-flavo-enzyme, is subject to carbon catabolite repression by both glucose and maltose, and that the repression is mediated at the transcriptional level. This paper describes the results of an investigation of CDH gene transcription in cellulolytic cultures of T. versicolor, in the presence of other additional carbon sources such as glucose, arabinose, and xylose. Using real time polymerase chain reaction (RT-PCR) assay methods in the presence of these other additional carbon sources, the levels of repression observed are quantitatively determined in an effort to obtain more accurate measurements of carbon catabolite repression of CDH production in this ligninolytic fungus. Ninety-six hours after addition, results of the analysis showed reduction in CDH transcript levels of 19-fold for galactose, 92-fold for arabinose and 114-fold for xylose. The greatest repressive effect was exhibited by glucose. In this case the reduction in CDH transcript levels was 3400-fold. CDH plays an important role in lignin degradation, and there is also substantial interest in the biotechnological applications of CDH, most particularly in the pulp and paper industry. 24 refs., 4 figs.

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.

Differences between easy- and difficult-to-mill chickpea (Cicer arietinum L.) genotypes. Part III: free sugar and non-starch polysaccharide composition.

Science.gov (United States)

Wood, Jennifer A; Knights, Edmund J; Campbell, Grant M; Choct, Mingan

2014-05-01

Parts I and II of this series of papers identified several associations between the ease of milling and the chemical compositions of different chickpea seed fractions. Non-starch polysaccharides were implicated; hence, this study examines the free sugars and sugar residues. Difficult milling is associated with: (1) lower glucose and xylose residues (less cellulose and xyloglucans) and more arabinose, rhamnose and uronic acid in the seed coat, suggesting a more flexible seed coat that resists cracking and decortication; (2) a higher content of soluble and insoluble non-starch polysaccharide fractions in the cotyledon periphery, supporting a pectic polysaccharide mechanism comprising arabinogalacturonan, homogalacturonan, rhamnogalalcturonan, and glucuronan backbone structures; (3) higher glucose and mannose residues in the cotyledon periphery, supporting a lectin-mediated mechanism of adhesion; and (4) higher arabinose and glucose residues in the cotyledon periphery, supporting a mechanism involving arabinogalactan-proteins. This series has shown that the chemical composition of chickpea does vary in ways that are consistent with physical explanations of how seed structure and properties relate to milling behaviour. Seed coat strength and flexibility, pectic polysaccharide binding, lectins and arabinogalactan-proteins have been implicated. Increased understanding in these mechanisms will allow breeding programmes to optimise milling performance in new cultivars. © 2013 Society of Chemical Industry.

Isolation, purification and some structural features of the mucilaginous exudate from Musa paradisiaca.

Science.gov (United States)

Mondal, S K; Ray, B; Thakur, S; Ghosal, P K

2001-03-01

The water-soluble polysaccharides isolated from the vascular gel of Musa paradisiaca, were fractionated via anion exchange chromatography into four fractions. Fractionated polymers contained arabinose, xylose and galacturonic acid as major sugars, together with traces of galactose, rhamnose, mannose and glucose residues. Methylation analysis revealed the presence of a highly branched arabinoxylan with a significant amount of terminal arabinopyranosyl units and an arabinogalactan type I pectin. Periodate oxidation studies supported the results of methylation analysis.

Archaeal promoter architecture and mechanism of gene activation

DEFF Research Database (Denmark)

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

2011-01-01

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...... mechanisms include TFB (transcription factor B) recruitment by the ara-box-binding factor to activate gene expression and modulation of TFB recruitment efficiency to yield differential gene expression....

Regulated programmed lysis of recombinant Salmonella in host tissues to release protective antigens and confer biological containment

OpenAIRE

Kong, Wei; Wanda, Soo-Young; Zhang, Xin; Bollen, Wendy; Tinge, Steven A.; Roland, Kenneth L.; Curtiss, Roy

2008-01-01

We have devised and constructed a biological containment system designed to cause programmed bacterial cell lysis with no survivors. We have validated this system, using Salmonella enterica serovar Typhimurium vaccines for antigen delivery after colonization of host lymphoid tissues. The system is composed of two parts. The first component is Salmonella typhimurium strain χ8937, with deletions of asdA and arabinose-regulated expression of murA, two genes required for peptidoglycan synthesis a...

Microbial Production of Xylitol from L-arabinose by Metabolically Engineered Escherichia coli

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Xylitol is used commercially as a natural sweetener in some food products such as chewing gum, soft drinks, and confectionery. It is currently produced by chemical reduction of D-xylose derived from plant materials, mainly hemicellulosic hydrolysates from birch trees. Expanding the substrate range...

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

.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. DGGE results revealed no significant difference on the bacterial community composition between operational periods...

Involvement of ribosomal protein L6 in assembly of functional 50S ribosomal subunit in Escherichia coli cells

International Nuclear Information System (INIS)

Shigeno, Yuta; Uchiumi, Toshio; Nomura, Takaomi

2016-01-01

Ribosomal protein L6, an essential component of the large (50S) subunit, primarily binds to helix 97 of 23S rRNA and locates near the sarcin/ricin loop of helix 95 that directly interacts with GTPase translation factors. Although L6 is believed to play important roles in factor-dependent ribosomal function, crucial biochemical evidence for this hypothesis has not been obtained. We constructed and characterized an Escherichia coli mutant bearing a chromosomal L6 gene (rplF) disruption and carrying a plasmid with an arabinose-inducible L6 gene. Although this ΔL6 mutant grew more slowly than its wild-type parent, it proliferated in the presence of arabinose. Interestingly, cell growth in the absence of arabinose was biphasic. Early growth lasted only a few generations (LI-phase) and was followed by a suspension of growth for several hours (S-phase). This suspension was followed by a second growth phase (LII-phase). Cells harvested at both LI- and S-phases contained ribosomes with reduced factor-dependent GTPase activity and accumulated 50S subunit precursors (45S particles). The 45S particles completely lacked L6. Complete 50S subunits containing L6 were observed in all growth phases regardless of the L6-depleted condition, implying that the ΔL6 mutant escaped death because of a leaky expression of L6 from the complementing plasmid. We conclude that L6 is essential for the assembly of functional 50S subunits at the late stage. We thus established conditions for the isolation of L6-depleted 50S subunits, which are essential to study the role of L6 in translation. - Highlights: • We constructed an in vivo functional assay system for Escherichia coli ribosomal protein L6. • Growth of an E. coli ΔL6 mutant was biphasic when L6 levels were depleted. • The ΔL6 mutant accumulated 50S ribosomal subunit precursors that sedimented at 45S. • L6 is a key player in the late stage of E. coli 50S subunit assembly.

Involvement of ribosomal protein L6 in assembly of functional 50S ribosomal subunit in Escherichia coli cells

Energy Technology Data Exchange (ETDEWEB)

Shigeno, Yuta [Division of Applied Biology, Faculty of Textile Science and Technology, Shinshu University, Ueda 386-8567 (Japan); Uchiumi, Toshio [Department of Biology, Faculty of Science, Niigata University, Niigata 950-2181 (Japan); Nomura, Takaomi, E-mail: nomurat@shinshu-u.ac.jp [Division of Applied Biology, Faculty of Textile Science and Technology, Shinshu University, Ueda 386-8567 (Japan)

2016-04-22

Ribosomal protein L6, an essential component of the large (50S) subunit, primarily binds to helix 97 of 23S rRNA and locates near the sarcin/ricin loop of helix 95 that directly interacts with GTPase translation factors. Although L6 is believed to play important roles in factor-dependent ribosomal function, crucial biochemical evidence for this hypothesis has not been obtained. We constructed and characterized an Escherichia coli mutant bearing a chromosomal L6 gene (rplF) disruption and carrying a plasmid with an arabinose-inducible L6 gene. Although this ΔL6 mutant grew more slowly than its wild-type parent, it proliferated in the presence of arabinose. Interestingly, cell growth in the absence of arabinose was biphasic. Early growth lasted only a few generations (LI-phase) and was followed by a suspension of growth for several hours (S-phase). This suspension was followed by a second growth phase (LII-phase). Cells harvested at both LI- and S-phases contained ribosomes with reduced factor-dependent GTPase activity and accumulated 50S subunit precursors (45S particles). The 45S particles completely lacked L6. Complete 50S subunits containing L6 were observed in all growth phases regardless of the L6-depleted condition, implying that the ΔL6 mutant escaped death because of a leaky expression of L6 from the complementing plasmid. We conclude that L6 is essential for the assembly of functional 50S subunits at the late stage. We thus established conditions for the isolation of L6-depleted 50S subunits, which are essential to study the role of L6 in translation. - Highlights: • We constructed an in vivo functional assay system for Escherichia coli ribosomal protein L6. • Growth of an E. coli ΔL6 mutant was biphasic when L6 levels were depleted. • The ΔL6 mutant accumulated 50S ribosomal subunit precursors that sedimented at 45S. • L6 is a key player in the late stage of E. coli 50S subunit assembly.

US Army Institute of Surgical Research Annual Research Progress Report, FY 1980.

Science.gov (United States)

1980-10-01

Arabinose - - + - deaminase positive, urease negative, indole positive, ornithine nega- tive, glucose and inositol fermented, citrate utilized...portion of biopsy sample was plated on the surface of a screw-capped tissue culture bottle containing a layer of Sabouraud’s agar. Results of this series...this new system are illustrated in Figure I. The 8x4x4 foot chamber is constructed of 3/16 inch steel covered by a I inch layer of thermal insulation

[Determination of monosaccharides in Sargassum hemiphyllum (Turner) C. Ag. polysaccharides by ion chromatography].

Science.gov (United States)

Ou, Yunfu; Yin, Pinghe; Zhao, Ling

2006-07-01

Sargassum hemiphyllum polysaccharides (SHP) was extracted from dry Sargassum hemiphyllum (Turner) C. Ag. powder using 60 - 80 degrees C purified water and then hydrolyzed with 4.0 g/L trifluoroacetic acid at 80 degrees C. Without any derivatization reaction, the determination of monosaccharides in SHP was developed by anion-exchange chromatography with pulsed amperometric detection with an Au working electrode and an Ag/AgCl reference electrode. Monosaccharides were separated on a CarboPac PA10 anion-column (2 mm i. d. x 250 mm) by using isocratic elution consisting of 14 mmol/L sodium hydroxide at a flow rate of 0.20 mL/min. Six monosaccharides, xylose, galactose, arabinose, glucose, rhamnose and fructose, contained in SHP were separated and determined. Their contents in SHP were 2 200, 820, 98, 4 560, 358 and 740 mg/kg, respectively. The recoveries of the six monosaccharides were in the range 86.0% - 108.0%. The detection limits for these monosaccharides ranged from 5.6 to 89.6 microg/kg. The experimental results showed that SHP mainly consisted of xylose and glucose with smaller quantities of galactose, arabinose, rhamnose and fructose. This method is suitable for the determination of monosaccharides without any derivatization reaction at the level of microg/kg in dry algae with high sensitivity and good precision.

Preparation, characterization and antiglycation activities of the novel polysaccharides from Boletus snicus.

Science.gov (United States)

Liping, Sun; Xuejiao, Su; Yongliang, Zhuang

2016-11-01

Boletus snicus (BS) is one of the commercially important mushroom species. Two polysaccharides (BSP-1b and BSP-2b) were extracted and purified from the body of BS by DEAE-cellulose and Sephadex G-100 column chromatography. The average of molecular weight of BSP-1b and BSP-2b were 59.21kDa and 128.74kDa. BSP-1b is a heteropolysaccharide with a large number of glucose and a small amount of mannose, glucosamine hydrochloride and arabinose. The monosaccharide compositions of BSP-2b contain mannose, glucuronic acid, glucosamine hydrochloride, glucose, galactose, arabinose with the molar ratio of 10.70:6.95:12.05:12.57:1.83:1.00. The FTIR spectra and NMR analysis demonstrated that BSP-1b and BSP-2b existed pyranose ring structure and BSP-2b had high content of uronic acid. The antiglycation activities of BSP-1b and BSP-2b were investigated. The results showed BSP-1b and BSP-2b had high inhibitory effects on glycation and exhibited dose-dependent responses. BSP-2b showed stronger antiglycation activity than BSP-1b. This study indicated that the BSP-2b could effectively inhibit the formation of advanced glycation end-products. Copyright © 2016 Elsevier B.V. All rights reserved.

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

2015-03-30

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. 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. 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.

Effects of Xylanase Supplementation on Growth Performance, Nutrient Digestibility and Non-starch Polysaccharide Degradation in Different Sections of the Gastrointestinal Tract of Broilers Fed Wheat-based Diets

Directory of Open Access Journals (Sweden)

L. Zhang

2014-06-01

Full Text Available This experiment was performed to investigate the effects of exogenous xylanase supplementation on performance, nutrient digestibility and the degradation of non-starch polysaccharides (NSP in different sections of the gastrointestinal tract (GIT of broilers fed wheat-based diets. A total of 120 7-day-old Arbor Acres broiler chicks were randomly allotted to two wheat-based experimental diets supplemented with 0 or 1.0 g/kg xylanase. Each treatment was composed of 6 replicates with 10 birds each. Diets were given to the birds from 7 to 21 days of age. The results showed that xylanase supplementation did not affect feed intake, but increased body weight gain of broiler at 21 day of age by 5.8% (pjejunum>duodenum>>gizzard> caecum. The supplementation of xylanse increased ileal isomaltriose concentration (p<0.05, but did not affect the concentrations of isomaltose, panose and 1-kestose in the digesta of all GIT sections. These results suggest that supplementation of xylanase to wheat-based diets cuts the arabinoxylan backbone into small fragments (mainly arabinose and xylose in the ileum, jejunum and duodenum, and enhances digestibilites of nutrients by decreasing digesta viscosity. The release of arabinose and xylose in the small intestine may also be the important contributors to the growth-promoting effect of xylanase in broilers fed wheat-based diets.

Ethanol production from Dekkera bruxellensis in synthetic media with pentose

Directory of Open Access Journals (Sweden)

Carolina B. Codato

Full Text Available Abstract Ethanol is obtained in Brazil from the fermentation of sugarcane, molasses or a mixture of these. Alternatively, it can also be obtained from products composed of cellulose and hemicellulose, called “second generation ethanol - 2G”. The yeast Saccharomyces cerevisiae, commonly applied in industrial ethanol production, is not efficient in the conversion of pentoses, which is present in high amounts in lignocellulosic materials. This study aimed to evaluate the ability of a yeast strain of Dekkera bruxellensis in producing ethanol from synthetic media, containing xylose or arabinose, xylose and glucose as the sole carbon sources. The results indicated that D. bruxellensis was capable of producing ethanol from xylose and arabinose, with ethanol concentration similar for both carbon sources, 1.9 g L-1. For the fermentations performed with xylose and glucose, there was an increase in the concentration of ethanol to 5.9 g L-1, lower than the standard yeast Pichia stipitis (9.3 g L-1, but with similar maximum yield in ethanol (0.9 g g TOC-1. This proves that the yeast D. bruxellensis produced lower amounts of ethanol when compared with P. stipitis, but showed that is capable of fermenting xylose and can be a promising alternative for ethanol conversion from hydrolysates containing glucose and xylose as carbon source.

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)

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.

High-level expression, purification and antibacterial activity of bovine lactoferricin and lactoferrampin in Photorhabdus luminescens.

Science.gov (United States)

Tang, Zhiru; Zhang, Youming; Stewart, Adrian Francis; Geng, Meimei; Tang, Xiangsha; Tu, Qiang; Yin, Yulong

2010-10-01

Bovine lactoferricin (LFC) and bovine lactoferrampin (LFA) are two active fragments located in the N(1)-domain of bovine lactoferrin. Recent studies suggested that LFC and LFA have broad-spectrum activity against Gram-positive and Gram-negative bacteria. To date, LFC and LFA have usually been produced from milk. We report here the high-level expression, purification and characterization of LFC and LFA using the Photorhabdus luminescens expression system. After the cipA and cipB genes were deleted by ET recombination, the expression host P. luminescens TZR(001) was constructed. A synthetic LFC-LFA gene containing LFC and LFA was fused with the cipB gene to form a cipB-LFC-LFA gene. To obtain the expression vector pBAD-cipB-LFC-LFA, the cipB-LFC-LFA gene was cloned on the L-arabinose-inducible expression vector pBAD24. pBAD-cipB-LFC-LFA was transformed into P. luminescens TZR(001). The cipB-LFC-LFA fusion protein was expressed under the induction of L-arabinose and its yield reached 12 mg L(-1) bacterial culture. Recombinant LFC-LFA was released from cipB by pepsin. The MIC of recombinant LFC-LFA toward E. coli 0149, 0141 and 020 was 6.25, 12.5 and 3.175 microg ml(-1), respectively. Copyright 2010 Elsevier Inc. All rights reserved.

Model-based characterisation of growth performance and l-lactic acid production with high optical purity by thermophilic Bacillus coagulans in a lignin-supplemented mixed substrate medium.

Science.gov (United States)

Glaser, Robert; Venus, Joachim

2017-07-25

Three Bacillus coagulans strains were characterised in terms of their ability to grow in lignin-containing fermentation media and to consume the lignocellulose-related sugars glucose, xylose, and arabinose. An optical-density high-throughput screening was used for precharacterisation by means of different mathematical models for comparison (Logistic, Gompertz, Baranyi, Richards & Stannard, and Schnute). The growth response was characterised by the maximum growth rate and lag time. For a comparison of the screening and fermentation results, an unstructured mathematical model was proposed to characterise the lactate production, bacterial growth and substrate consumption. The growth model was then applied to fermentation procedures using wheat straw hydrolysates. The results indicated that the unstructured growth model can be used to evaluate lactate producing fermentation. Under the experimental fermentation conditions, one strain showed the ability to tolerate a high lignin concentration (2.5g/L) but lacked the capacity for sufficient pentose uptake. The lactate yield of the strains that were able to consume all sugar fractions of glucose, xylose and arabinose was ∼83.4%. A photometric measurement at 280nm revealed a dynamic change in alkali-lignin concentrations during lactate producing fermentation. A test of decolourisation of vanillin, ferulic acid, and alkali-lignin samples also showed the decolourisation performance of the B. coagulans strains under study. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

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)

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.

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. Copyright © 2015 Elsevier B.V. All rights reserved.

A unique polysaccharide containing 3-O-methylarabinose and 3-O-methylgalactose from Tinospora sinensis.

Science.gov (United States)

Nagar, Shipra; Hensel, Andreas; Mischnick, Petra; Kumar, Vineet

2018-08-01

Tinospora sinensis (Lour.) Merrill is of great therapeutic significance in Indian traditional medicine. Crude polysaccharides were isolated from methanol pre-extracted stems of dried material by successive extractions with cold water, hot water and NaOH (0.25 mol/L) in 0.98, 0.55 and 0.70 % yields respectively. Cold water soluble polysaccharides (CWSP) were purified and fractionated by ion exchange chromatography on DEAE-Sephacel. Neutral polysaccharides were further fractionated on Sepharose CL6B to yield three fractions TW1, TW2, TW3. The study further focuses on structural elucidation of TW1. TW1 was obtained in 0.8 % yield relative to CWSP, with MW of 1.6 × 10 5  Da. It was composed of 3-O-methyl-arabinose, 3-O-methyl-galactose and galactose in molar ratio of 1.0:6.3:0.9 respectively. Based on per-deuteromethylation, NMR and ESI-MS analyses, TW1 was composed of 1,4-linked 3-O-methyl-β-d-galactopyranose and β-d-galactopyranose backbone with branching at O-6 of 3-O-methyl-β-d-galactosyl residues by 1,5-linked 3-O-methyl-α-l-arabinofuranoside chains. 3-O-methyl-arabinose and 3-O-methyl-galactose have first ever been reported in any polysaccharide and Tinospora genus, respectively. Copyright © 2018 Elsevier Ltd. All rights reserved.

Structure analysis of a novel heteroxylan from the stem of Dendrobium officinale and anti-angiogenesis activities of its sulfated derivative.

Science.gov (United States)

Yue, Han; Liu, Yanqiu; Qu, Huanhuan; Ding, Kan

2017-10-01

Dendrobium officinale Kimura et Migo (Tie-Pi-Shi-Hu), a precious folk medicine exhibiting multiple bioactivities, including antitumor, immune-enhancing and so on. Although evidences showed polysaccharide is one of the major bioactive substances from this herb, several of them were homogenous with fine structures elucidated. In this study, we showed a novel homogeneous heteroxylan obtained from alkali-extracted crude polysaccharide. It composed of arabinose, xylose, glucose and 4-O-methylglucuronic acid (4-MGA) as well as trace amount of rhamnose and galactose in a ratio of 8.9:62.7:8.5:12.3:3.9:3.7. We further showed that it contained a backbone of 1,4-linked β-d-xylan, with branches of 1,4-linked α-d-glucose, 1,3-linked α-l-rhamnose, and terminal-linked α-l-arabinose, β-d-galactose, 4-MGA, and β-d-xylose directly or indirectly attached to C-2 position of glycosyl residues on backbone. The sulfated derivative with substitution degree about 0.9 was prepared according to the chlorosulfonic acid (CSA)-pyridine method. Bioactivity tests suggested that the sulfated polysaccharide could significantly disrupt tube formation and inhibit the migration of human microvascular endothelial cells (HMEC-1) at a low concentration (0.29μM) in a dose-dependent way without significant cytotoxity. Copyright © 2017 Elsevier B.V. All rights reserved.

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.

Mold biomass as a potential source of nutrient proteins

Energy Technology Data Exchange (ETDEWEB)

Fuska, J; Kollarova, A

1977-01-01

In submerged cultures of Penicillium resticulosum, Mycelium sterilium, Gibberella fuiikuroi, and Coprinus species grown for 72 hours in medium containing 5 to 7% sawdust hydrolyzate, 1.28 to 1.45 g of dry biomass per 100 mL of culture was produced with 28.1 to 35.3% total amino acids and 15 to 18% essential amino acids; 80 to 90% of the cellular protein was digestible. Mannose, glucose and galactose of the hydrolyzate were utilized faster than xylose and arabinose.

Influence of l-Leucine and l-Alanine on Lrp Regulation of foo, Coding for F1651, a Pap Homologue

OpenAIRE

Berthiaume, Frédéric; Crost, Cécile; Labrie, Vincent; Martin, Christine; Newman, Elaine B.; Harel, Josée

2004-01-01

The foo operon encodes F1651 fimbriae that belong to the P-regulatory family and are synthesized by septicemic Escherichia coli. Using an Lrp-deficient host and the lrp gene cloned under the arabinose pBAD promoter, we demonstrated that foo was transcribed proportionally to the amount of Lrp synthesized. l-Leucine and l-alanine decreased drastically the steady-state transcription of foo and modified phase variation, independently of the presence of FooI. Specific mutations in the C-terminal r...

Postradiation reactions of free radicals in crystalline carbohydrates

International Nuclear Information System (INIS)

Yudin, I.V.; Filyanin, G.A.; Panasyuk, S.L.

1990-01-01

In order to determine the nature of the elementary stages of chain process of formation of molecular products in irradiated carbohydrates, the kinetics of their accumulation in crystalline matrices at 100-400 K were investigated. Chain formation of carbonyl products in xylose crystals irradiated at 100 K was identified at temperatures above 240 K and in saccharose, rhamnose, and arabinose crystals at T > 273 K. Chain formation of hydroxy acids with a radiochemical yield of ∼ 150 molecules/100 eV was confirmed in crystalline lactose

Xylitol production from xylose mother liquor: a novel strategy that combines the use of recombinant Bacillus subtilis and Candida maltosa

OpenAIRE

Jiang Mingguo; Lv Jiyang; Wang Ben; Cheng Hairong; Lin Shuangjun; Deng Zixin

2011-01-01

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 d...

Synthesizing labeled compounds

International Nuclear Information System (INIS)

London, R.E.; Matwiyoff, N.A.; Unkefer, C.J.; Walker, T.E.

1983-01-01

A metabolic study is presented of the chemical reactions provided by isotopic labeling and NMR spectroscopy. Synthesis of 13 C-labeled D-glucose, a 6-carbon sugar, involves adding a labeled nitrile group to the 5-carbon sugar D-arabinose by reaction with labeled hydrogen cyanide. The product of this reaction is then reduced and hydrolyzed to a mixture of the labeled sugars. The two sugars are separated by absorption chromotography. The synthesis of 13 C-labeled L-tyrosine, an amino acid, is also presented

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.

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.

An arabinoxyloglucan isolated from the midrib of the leaves of Nicotiana tabacum

Energy Technology Data Exchange (ETDEWEB)

Eda, S; Kato, K

1978-01-01

The structure of an arabinoxyloglucan, separated from the hemicellulosic polysaccharides of the midrib of the leaves of Nicotiana tabacum, was investigated by methylation analyses before and after mild acid hydrolysis, acetolysis and cellulase-degradation. The arabinoxyloglucan consists of L-arabinose, D-xylose and D-glucose in a molar ratio of 13:33:54, and has a backbone of ..beta..-(1..-->..4)-linked D-glucopyranosyl residues. Some of the glucopyranosyl residues are attached at the 6 position by single ..cap alpha..-D-xylopyranosyl and ..cap alpha..-L-arabinofuranosyl-(1..-->..2)-..cap alpha..-D-xylopyranosyl side chains.

Ethylene-producing bacteria that ripen fruit.

Science.gov (United States)

Digiacomo, Fabio; Girelli, Gabriele; Aor, Bruno; Marchioretti, Caterina; Pedrotti, Michele; Perli, Thomas; Tonon, Emil; Valentini, Viola; Avi, Damiano; Ferrentino, Giovanna; Dorigato, Andrea; Torre, Paola; Jousson, Olivier; Mansy, Sheref S; Del Bianco, Cristina

2014-12-19

Ethylene is a plant hormone widely used to ripen fruit. However, the synthesis, handling, and storage of ethylene are environmentally harmful and dangerous. We engineered E. coli to produce ethylene through the activity of the ethylene-forming enzyme (EFE) from Pseudomonas syringae. EFE converts a citric acid cycle intermediate, 2-oxoglutarate, to ethylene in a single step. The production of ethylene was placed under the control of arabinose and blue light responsive regulatory systems. The resulting bacteria were capable of accelerating the ripening of tomatoes, kiwifruit, and apples.

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...... Of D-Xylose into ethanol; (ii) test for viability and ethanol production in pretreated wheat straw hemicellulose hydrolysate; (iii) test for tolerance against high D-xylose concentrations. A total of 86 enrichment cultures and 58 pure cultures were tested and five candidates were selected which...

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...

Pilot plant studies of the bioconversion of cellulose and production of ethanol

Energy Technology Data Exchange (ETDEWEB)

Wilke, C.R.

1977-01-31

Progress is reported in several areas of research. The following cellulosic raw materials were selected for study: wheat, barley, and rice straws, rice hulls, sorghum, corn stover, cotton gin trash, newsprint, ground wood, and masonite steam-treated Douglas fir and redwood. Samples were collected, prepared, and analyzed for hexosans, pentosans, lignin, ash, and protein. Results of acid extraction and enzymatic hydrolysis are discussed. Yields of glucose, polyglucose, xylose, and arabinose are reported. Progress in process design and economic studies, as well as pilot plant process development and design studies, is summarized. (JGB)

New Culture Medium Containing Ionic Concentrations of Nutrients Similar to Concentrations Found in the Soil Solution †

Science.gov (United States)

Angle, J. Scott; McGrath, Stephen P.; Chaney, Rufus L.

1991-01-01

A new growth medium which closely approximates the composition of the soil solution is presented. This soil solution equivalent (SSE) medium contains the following components (millimolar): NO3, 2.5; NH4, 2.5; HPO4, 0.005; Na, 2.5; Ca, 4.0; Mg, 2.0; K, 0.503; Cl, 4.0; SO4, 5.0; ethylenediamine-di(o-hydroxyphenylacetic acid), 0.02; and MES [2-(N-morpholino)ethanesulfonic acid] (to maintain the pH at 6.0), 10, plus 0.1% arabinose. The advantages of the SSE medium are discussed. PMID:16348614

Some Peculiarities of Growth and Functional Activity of Escherichia coli Strain from Probiotic Formula "ASAP"

OpenAIRE

Marine A. Balayan; Susanna S. Mirzabekyan; Marine Isajanyan; Zaven S. Pepoyan; Аrmen H. Trchounian; Аstghik Z. Pepoyan; Helena Bujdakova

2010-01-01

It has been shown that pH 7,3 and 37 0C are the optimal condition for the growth of E. coli “ASAP". The cells grow well on Glucose, Lactose, D-Mannitol, D-Sorbitol, (+)-Xylose, L- (+)-Arabinose and Dulcitol. No growth has been observed on Sucrose, Inositol, Phenylalanine, and Tryptophan. The strain is sensitive to a range of antibiotics. The present study has demonstrated that E. coli “ASAP" inhibit the growth of S. enterica ATCC #700931 in vitro. The studies on conjugating activity has revea...

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.

In Vitro and In Vivo Antioxidant Activity of a Water-Soluble Polysaccharide from Dendrobium denneanum

Directory of Open Access Journals (Sweden)

XingJin He

2011-02-01

Full Text Available 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.

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

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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. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

CARACTERIZAÇÃO BIOQUÍMICA DE AMOSTRAS DE Haemophilus parasuis ISOLADAS DE SUÍNOS NA REGIÃO SUL DO BRASIL

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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.

Evaluation of wheat stillage for ethanol production by recombinant Zymomonas mobilis

Energy Technology Data Exchange (ETDEWEB)

Davis, L.; Peiris, P. [University of Western Sydney, Penrith (Australia). School of Science, Food and Horticulture; Young-Jae Jeon; Svenson, C.; Rogers, P. [University of New South Wales, Sydney (Australia). School of Biotechnology and Biomolecular Sciences; Pearce, J. [Manildra Group, Bomaderry (Australia)

2005-07-01

Stillage is the main residue from the starch-to-ethanol fermentation process.Carbohydrates (hemicellulose and cellulose) comprise approximately 50% (w/w)of the total components of stillage. Conversion of the hemicellulose and cellulose to fermentable sugars and then to ethanol has the potential to significantly increase the efficiency of the process. The hydrolysis of stillage to fermentable sugars was optimised using 2% (v/v) H{sub 2}SO{sub 4} at 100{sup o}C for 5.5 h and produced 18 g/L xylose, 11.5 g/L arabinose and 6.5 g/L glucose from 120 g/L stillage. Further hydrolysis using enzymes increased the release of glucose by 61%. Furfural, acetate and lactate were the main inhibitors present in the acid hydrolysate of stillage. The lignin-derived inhibitors hydroxymethylfuraldehyde, hydroxybenzaldehyde, vanillin and syringaldehyde were not detected. Neutralisation of the hydrolysate with lime to pH 5 decreased the concentration of furfural by 50%. Fermentation of hydrolysate supplemented with glucose 10 g/L, by recombinant Zymomonas mobilis ZM4(pZB5), produced 11 g/L of ethanol after 70 h, with residual xylose 12 g/L. Supplementation of the hydrolysate with 5 g/L yeast extract and 40 g/L glucose produced 28 g/L ethanol with 2.6 g/L residual xylose after 18 h. Arabinose was not utilised by this particular recombinant strain. From the results, Z. mobilis ZM4(pZB5) may be a suitable candidate for the fermentation of both glucose and xylose in stillage acid hydrolysates. (author)

Physicochemical Characterization of Polysaccharides with Macrophage Immunomodulatory Activities Isolated from Red Ginseng (Panax ginseng C. A. Meyer

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Liang Zheng

2017-01-01

Full Text Available In this study, four polysaccharide fractions designated as RGP1, RGP2, RGP3, and RGP4 were isolated from red ginseng by DEAE-52 cellulose chromatography, and their macrophage immunomodulatory activities were investigated. The results revealed that the proliferation, NO production, and neutral red phagocytosis of RAW 264.7 macrophage cells in groups treated with RGP1 and RGP2 in vitro were increased significantly compared to RGP3 and RGP4. In addition, the level of TNF-α in RAW 264.7 cells was significantly increased in RGP1 and RGP2 groups. All the results consistently indicated that polysaccharide fractions RGP1 and RGP2 had strong macrophage immunomodulatory activities. Furthermore, RGP1 and RGP2 were purified by Sephadex G-100 column and RGP2 was further fractionated into a homogeneous fraction RGP2-1, with the molecular weight of 2.16 × 104 Da. The analysis of monosaccharide composition revealed that RGP1 was composed of arabinose, glucose, and galactose with a relative molecular ratio of 0.02 : 0.88 : 0.10. RGP2-1 was composed of rhamnose, arabinose, glucose, and galactose with a relative molecular ratio of 0.02 : 0.10 : 0.77 : 0.11. These results provided evidences that the neutral polysaccharide fractions RGP1 and RGP2 possessed significant immunomodulatory activity and could be explored as a promising natural immunomodulating agent applied in functional foods or medicines.

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

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

2009-11-16

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

Model Study To Assess Softwood Hemicellulose Hydrolysates as the Carbon Source for PHB Production in Paraburkholderia sacchari IPT 101.

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Dietrich, Karolin; Dumont, Marie-Josée; Schwinghamer, Timothy; Orsat, Valérie; Del Rio, Luis F

2018-01-08

Softwood hemicellulose hydrolysates are a cheap source of sugars that can be used as a feedstock to produce polyhydroxybutyrates (PHB), which are biobased and compostable bacterial polyesters. To assess the potential of the hemicellulosic sugars as a carbon source for PHB production, synthetic media containing softwood hemicellulose sugars (glucose, mannose, galactose, xylose, arabinose) and the potentially inhibitory lignocellulose degradation products (acetic acid, 5-hydroxymethylfurfural (HMF), furfural, and vanillin) were fermented with the model strain Paraburkholderia sacchari IPT 101. Relative to pure glucose, individual fermentation for 24 h with 20 g/L mannose or galactose exhibited maximum specific growth rates of 97% and 60%, respectively. On the other hand, with sugar mixtures of glucose, mannose, galactose, xylose, and arabinose, the strain converted all sugars simultaneously to reach a maximum PHB concentration of 5.72 g/L and 80.5% PHB after 51 h. The addition of the inhibitor mixture at the following concentration, sodium acetate (2.11 g/L), HMF (0.67 g/L), furfural (0.66 g/L), and vanillin (0.93 g/L), to the sugar mixture stopped the growth entirely within 24 h. Individually, the inhibitors either had no effect or only reduced growth. Moreover, it was found that a bacterial inoculum with high initial cell density (optical density, OD ≥ 5.6) could overcome the growth inhibition to yield an OD of 13 within 24 h. Therefore, softwood hemicellulose sugars are viable carbon sources for PHB production. Nevertheless, real softwood hemicellulose hydrolysates need detoxification or a high inoculum to overcome inhibitory effects and allow bacterial growth.

Enzymatic depolymerization of gum tragacanth: bifidogenic potential of low molecular weight oligosaccharides.

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Gavlighi, Hassan Ahmadi; Michalak, Malwina; Meyer, Anne S; Mikkelsen, J Dalgaard

2013-02-13

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 gossypinus was enzymatically depolymerized using Aspergillus niger pectinases (Pectinex BE Color). The enzymatically degraded products were divided into three molecular weight fractions via membrane separation: HAG1 10 kDa. Compositional and linkage analyses showed 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 and galactose content. The growth-stimulating potential of the three enzymatically produced gum tragacanth fractions was evaluated via growth assessment on seven different probiotic strains in single-culture fermentations on Bifidobacterium longum subsp. longum (two strains), B. longum subsp. infantis (three strains), Lactobacillus acidophilus , B. lactis, and on one pathogenic strain of Clostridium perfringens . The fractions HAG1 and HAG2 consistently promoted higher growth of the probiotic strains than HAG3, especially of the three B. longum subsp. infantis strains, and the growth promotion on HAG1 and HAG2 was better than that on galactan (control). HAG3 completely inhibited the growth of the C. perfringens strain. Tragacanth gum is thus a potential source of prebiotic carbohydrates that exert no viscosity effects and which may find use as natural functional food ingredients.

Extraction of Glucuronoarabinoxylan from Quinoa Stalks (Chenopodium quinoa Willd.) and Evaluation of Xylooligosaccharides Produced by GH10 and GH11 Xylanases.

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Salas-Veizaga, Daniel Martin; Villagomez, Rodrigo; Linares-Pastén, Javier A; Carrasco, Cristhian; Álvarez, María Teresa; Adlercreutz, Patrick; Nordberg Karlsson, Eva

2017-10-04

Byproducts from quinoa are not yet well explored sources of hemicellulose or products thereof. In this work, xylan from milled quinoa stalks was retrieved to 66% recovery by akaline extraction using 0.5 M NaOH at 80 °C, followed by ethanol precipitation. The isolated polymer eluted as a single peak in size-exclusion chromatography with a molecular weight of >700 kDa. Analysis by Fourier transform infrared spectroscopy and nuclear magnetic resonance (NMR) combined with acid hydrolysis to monomers showed that the polymer was built of a backbone of β(1 → 4)-linked xylose residues that were substituted by 4-O-methylglucuronic acids, arabinose, and galactose in an approximate molar ratio of 114:23:5:1. NMR analysis also indicated the presence of α(1 → 5)-linked arabinose substituents in dimeric or oligomeric forms. The main xylooligosaccharides (XOs) produced after hydrolysis of the extracted glucuronoarabinoxylan polymer by thermostable glycoside hydrolases (GHs) from families 10 and 11 were xylobiose and xylotriose, followed by peaks of putative substituted XOs. Quantification of the unsubstituted XOs using standards showed that the highest yield from the soluble glucuronoarabinoxylan fraction was 1.26 g/100 g of xylan fraction, only slightly higher than the yield (1.00 g/100 g of xylan fraction) from the insoluble fraction (p 0.05). This study shows that quinoa stalks represent a novel source of glucuronoarabinoxylan, with a substituent structure that allowed for limited production of XOs by GH10 or GH11 enzymes.

Compositional profile and variation of Distillers Dried Grains with Solubles from various origins with focus on non-starch polysaccharides

DEFF Research Database (Denmark)

Pedersen, Mads Brøgger; Dalsgaard, S.; Knudsen, Knud Erik Bach

2014-01-01

nutrients (e.g. protein, fat, fibre and minerals) after fermentation of starch to ethanol. Corn DDGS differentiated from wheat DDGS by a greater content of fat (P≤0.006), insoluble-NSP (Pcellulose (P=0.032), and arabinose/xylose (P....001). Wheat DDGS differentiated from corn DDGS by a greater content of ash (P=0.001), soluble-NSP (Plignin (P...Corn-, wheat- and mixed cereal Distillers' Dried Grains with Solubles (DDGS) were investigated for compositional variability among DDGS origins, ethanol plants, and the relationship between corn and corresponding DDGS. A total of 138 DDGS samples were analyzed by use of Near Infrared Reflectance...

Stabilization of emulsions by gum tragacanth (Astragalus spp.) correlates to the galacturonic acid content and methoxylation degree of the gum

DEFF Research Database (Denmark)

Ahmadi Gavlighi, Hassan; Meyer, Anne S.; Abang Zaidel, Dayang Norulfairuz

2013-01-01

Gum tragacanth samples from six species of Iranian Astragalus bush plants (“goat's-horn”) were evaluated for their emulsion stabilizing effects and their detailed chemical composition in order to examine any possible correlation between the make-up and the emulsion stabilizing properties of gum......:50 (A. rahensis, A. microcephalus, A. compactus) or tipped toward higher bassorin than tragacanthin (A. gossypinus). The monosaccharide make-up of the six gums also varied, but all the gums contained relatively high levels of galacturonic acid (∼100–330 mg/g), arabinose (50–360 mg/g), xylose (∼150...

Production of vanillin by metabolically engineered Escherichia coli.

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Yoon, Sang-Hwal; Li, Cui; Kim, Ju-Eun; Lee, Sook-Hee; Yoon, Ji-Young; Choi, Myung-Suk; Seo, Weon-Taek; Yang, Jae-Kyung; Kim, Jae-Yeon; Kim, Seon-Won

2005-11-01

E. coli was metabolically engineered to produce vanillin by expression of the fcs and ech genes from Amycolatopsis sp. encoding feruloyl-CoA synthetase and enoyl-CoA hydratase/aldolase, respectively. Vanillin production was optimized by leaky expression of the genes, under the IPTG-inducible trc promoter, in complex 2YT medium. Supplementation with glucose, fructose, galactose, arabinose or glycerol severely decreased vanillin production. The highest vanillin production of 1.1 g l(-1) was obtained with cultivation for 48 h in 2YT medium with 0.2% (w/v) ferulate, without IPTG and no supplementation of carbon sources.

6-Azido hyacinthacine A2 gives a straightforward access to the first multivalent pyrrolizidine architectures.

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D'Adamio, Giampiero; Parmeggiani, Camilla; Goti, Andrea; Moreno-Vargas, Antonio J; Moreno-Clavijo, Elena; Robina, Inmaculada; Cardona, Francesca

2014-08-28

The synthesis of the first multivalent pyrrolizidine iminosugars is reported. The key azido intermediates 4 and 31 were prepared after suitable synthetic elaboration of the cycloadduct obtained from 1,3-dipolar cycloaddition of D-arabinose derived nitrone to dimethylacrylamide. The key step of the strategy was the stereoselective installation of an azido moiety at C-6 of the pyrrolizidine skeleton. The click reaction with different monovalent and dendrimeric alkyne scaffolds allowed the preparation of a library of new mono- and multivalent pyrrolizidine compounds that were preliminarily assayed as glycosidase inhibitors towards a panel of commercially available glycosyl hydrolases.

Inhibition of intestinal disaccharidase activity by pentoses

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Halschou-Jensen, Kia

on carbohydrate- ingesting enzymes activity in vitro and possible effects on human postprandial blood response. In paper 1 the effects of sugar beet polyphenols from molasses and the potential inhibition of sucrase activity in vitro, was investigated. Two different polyphenol-rich fractions from chromatographic...... separation of molasses from sugar beets and pure ferulic acid were tested. We found no effects of the two fractions of molasses. The pure ferulic acid indicated an inhibition of sucrase in vitr. Both in vitro and in vivo studies have investigated the effects of L-arabinose and D-xylose on carbohydrate...

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

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

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

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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

Chemical composition of caecal contents in the fowl in relation to dietary fibre level and time of day.

Science.gov (United States)

Savory, C J; Knox, A I

1991-01-01

1. Immature hens were preconditioned to a standard diet containing either 0, 100, 200 or 400 g/kg of added dried grass, 200 g/kg powdered cellulose, or 200 g/kg grass with an enzyme supplement, and were killed at either 10.30, 12.30 or 15.30 hr (after measurement of intestinal sugar absorption reported elsewhere). 2. Contents of caeca removed from these birds immediately after death were weighed and analysed for pH, uric acid, free sugars and volatile fatty acids, and the results related to dietary fibre level and time of day (of death). 3. Wet weights and uric acid concentrations of caecal contents both increased with increasing grass in the diet; neither measure varied with time, thus supporting the proposal that filling of caeca is continuous. Values of pH were all close to neutrality. 4. Mean molar concentrations of glucose, galactose, mannose, xylose, arabinose, fucose and rhamnose were in the proportions 36:2:3:1:4:1:1, respectively. Xylose and rhamnose declined with increasing grass; as did glucose, galactose and mannose with added cellulose; glucose, mannose and arabinose levels changed with time. The relative abundance of glucose in caecal contents should be taken into account when estimating contributions of fermentation products to energy balance. 5. Mean concentrations of acetate, propionate, butyrate, iso-butyrate, valerate and iso-valerate were in the proportions 72:22:16:1:2:2. Acetate declined and iso-valerate increased with increasing grass; the cellulose and enzyme treatments caused increases in acetate and valerate respectively; butyrate, iso-butyrate and iso-valerate levels changed with time.

Transformation of oil palm fronds into pentose sugars using copper (II) sulfate pentahydrate with the assistance of chemical additive.

Science.gov (United States)

Loow, Yu-Loong; Wu, Ta Yeong

2018-06-15

Among the chemical pretreatments available for pretreating biomass, the inorganic salt is considered to be a relatively new but simple reagent that offers comparable pentose (C5) sugar recoveries as the conventional dilute acid hydrolysis. This study investigated the effects of different concentrations (1.5-6.0% (v/v)) of H 2 O 2 or Na 2 S 2 O 8 in facilitating CuSO 4 ·5H 2 O pretreatment for improving pentose sugar recovery from oil palm fronds. The best result was observed when 0.2 mol/L of CuSO 4 ·5H 2 O was integrated with 4.5% (v/v) of Na 2 S 2 O 8 to recover 8.2 and 0.9 g/L of monomeric xylose and arabinose, respectively in the liquid fraction. On the other hand, an addition of 1.5% (v/v) of H 2 O 2 yielded approximately 74% lesser total pentose sugars as compared to using 4.5% (v/v) Na 2 S 2 O 8 . By using CuSO 4 ·5H 2 O alone (control), only 0.8 and 1.0 g/L xylose and arabinose, respectively could be achieved. The results mirrored the importance of using chemical additives together with the inorganic salt pretreatment of oil palm fronds. Thus, an addition of 4.5% (v/v) of Na 2 S 2 O 8 during CuSO 4 ·5H 2 O pretreatment of oil palm fronds at 120 °C and 30 min was able to attain a total pentose sugar yield up to ∼40%. Copyright © 2017 Elsevier Ltd. All rights reserved.

Absence of arabinan in the side chains of the pectic polysaccharides strongly associated with cell walls of Nicotiana plumbaginifolia non-organogenic callus with loosely attached constituent cells.

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Iwai, H; Ishii, T; Satoh, S

2001-10-01

When leaf disks from haploid plants of Nicotiana plumbaginifolia Viv. were transformed with T-DNA and cultured on shoot-inducing medium, nonorganogenic callus. designated nolac (for non-organogenic callus with loosely attached cells), appeared on approximately 7% of leaf disks. In contrast, normal callus was generated on T-DNA-transformed leaf disks from diploid plants and on non-transformed leaf disks from haploid and diploid plants. Transmission electron microscopy revealed that the middle lamellae and the cell walls of one line of mutant callus (nolac-H14) were barely stained by ruthenium red. even after demethylesterification with NaOH, whereas the entire cell wall and the middle lamella were strongly stained in normal callus. In cultures of nolac-H14 callus, the level of sugar components of pectic polysaccharides in the hemicellulose fraction was reduced and that in the culture medium was elevated, as compared with cultures of normal callus. These results indicate that pectic polysaccharides are not retained in the cell walls and middle lamellae of nolac-H14 callus. In nolac-H14, the ratio of arabinose to galactose was low in the pectic polysaccharides purified from all cell wall fractions and from the medium, in particular, in the hemicellulose fractions. The low levels of arabinofuranosyl (T-Araf, 5-Araf, 2,5-Araf, and 3,5-Araf) residues in the pectic polysaccharides of the hemicellulosic fraction of nolac-H,14 indicated that no neutral-sugar side chains, composed mainly of linear arabinan. were present in nolac-H14. Arabinose-rich pectins. which are strongly associated with cellulose-hemicellulose complexes, might play an important role in intercellular attachment in the architecture of the cell wall.

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...

Alguns aspectos químicos, físico-químicos e estruturais da mucilagem extraída de folhas de Pereskia aculeata Mill

OpenAIRE

Sierakowski, Maria Rita, 1953-

2013-01-01

Resumo: O pó atônico tratado com benzeno-etanol (2:1, v/v) de folhas de Pereskia aculeata, foi submetido a exaustiva extração com água quente e o extrato, após precipitação etanólica, forneceu um heteropolissacarídeo mucilaginoso. Após sucessivas desproteinizações, pelo método de Sevag, o polímero apresentou 36,01 de acucar total e a seguinte composição: ramnose, 9,2%; fucose, 2,5%; ribose, 2,51; arabinose, 27,51; xilose, 2,5%; manose, 3,0%;ga lactose, 40,8%, glucose, 3,0%, acido-D-galacturo...

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 t......-arabinans, arabinogalactan proteins and arabinoxylans) as the major contributors in ensuring flexibility is maintained and rehydration is facilitated in these plants....

Rheology and microstructure of gels based on wheat arabinoxylans enzymatically modified in arabinose and xylose

Science.gov (United States)

Atomic force microscopy (AFM) was used to investigate the microstructure of laccase-induced arabinoxylan (AX) gels for the first time. The effect of the degree of substitution (DS) of AX on gel microstructure was investigated by AFM. AX with three DS values (0.68, 0.61 and 0.51) were enzymatically t...

Structure of the effector-binding domain of the arabinose repressor AraR from Bacillus subtilis

Czech Academy of Sciences Publication Activity Database

Procházková, Kateřina; Čermáková, Kateřina; Pachl, Petr; Sieglová, Irena; Fábry, Milan; Otwinowski, Z.; Řezáčová, Pavlína

2012-01-01

Roč. 68, č. 2 (2012), s. 176-185 ISSN 0907-4449 R&D Projects: GA MŠk ME08016 Institutional research plan: CEZ:AV0Z40550506; CEZ:AV0Z50520514 Keywords : repressor * dimerization * effector binding * isothermal titration calorimetry Subject RIV: CE - Biochemistry Impact factor: 14.103, year: 2012

Perfil químico da parede celular e suas implicações na digestibilidade de Brachiaria brizantha e Brachiaria humidicola Chemical profile of cell wall and its implications on Brachiaria brizantha and Brachiaria humidicola digestibility

Directory of Open Access Journals (Sweden)

Cláudio José F. Alves de Brito

2003-12-01

Full Text Available No presente trabalho foram determinadas a composição química e a digestibilidade de diversas frações de Brachiaria brizantha e Brachiaria humidicola, após 70 dias de crescimento. O delineamento experimental foi inteiramente casualizado com cinco repetições para cada espécie. As plantas coletadas foram subdivididas nas frações apical, mediana e basal para as folhas e mediana e basilar para caules, de acordo com sua localização. Foram determinadas as concentrações de fibra em detergente neutro (FDN, proteína bruta (PB, lignina, ácido p_cumárico, ácido ferúlico e açúcares neutros (glicose, xilose e arabinose e a digestibilidade in situ após 48 horas de período de incubação ruminal. As diferentes frações das espécies estudadas apresentam distinta composição química, cujos efeitos são observados na digestibilidade. A B. brizantha apresentou maiores concentrações de FDN no caule e PB nas folhas. Isto resultou em coeficientes de digestibilidade maiores em relação à B. humidicola. A diferença de digestibilidade entre caule e folhas e nas frações mais velhas pode estar relacionada ao tipo de condensação da lignina presente nos tecidos. Evidências na concentração e na proporção dos ácidos p_cumárico e ferúlico sugerem esta relação. A concentração de ácidos fenólicos esteve relacionada com a digestibilidade da matéria seca e a lignina com a digestibilidade da FDN. A análise dos ácidos fenólicos pode se constituir em importante ferramenta para avaliar o grau de condensação da lignina na parede celular dos diferentes tecidos das plantas forrageiras. A concentração de açúcares neutros não apresentou um padrão definido na composição dos diferentes tecidos. A arabinose foi o único açúcar que apresentou relações com a digestibilidade da matéria seca e com a concentração de ácidos fenólicos.In the present paper the chemical composition and digestibility of several Brachiaria

Enzymatic Mechanism for Arabinan Degradation and Transport in the Thermophilic Bacterium Caldanaerobius polysaccharolyticus.

Science.gov (United States)

Wefers, Daniel; Dong, Jia; Abdel-Hamid, Ahmed M; Paul, Hans Müller; Pereira, Gabriel V; Han, Yejun; Dodd, Dylan; Baskaran, Ramiya; Mayer, Beth; Mackie, Roderick I; Cann, Isaac

2017-09-15

The plant cell wall polysaccharide arabinan provides an important supply of arabinose, and unraveling arabinan-degrading strategies by microbes is important for understanding its use as a source of energy. Here, we explored the arabinan-degrading enzymes in the thermophilic bacterium Caldanaerobius polysaccharolyticus and identified a gene cluster encoding two glycoside hydrolase (GH) family 51 α-l-arabinofuranosidases (CpAbf51A, CpAbf51B), a GH43 endoarabinanase (CpAbn43A), a GH27 β-l-arabinopyranosidase (CpAbp27A), and two GH127 β-l-arabinofuranosidases (CpAbf127A, CpAbf127B). The genes were expressed as recombinant proteins, and the functions of the purified proteins were determined with para -nitrophenyl ( p NP)-linked sugars and naturally occurring pectin structural elements as the substrates. The results demonstrated that CpAbn43A is an endoarabinanase while CpAbf51A and CpAbf51B are α-l-arabinofuranosidases that exhibit diverse substrate specificities, cleaving α-1,2, α-1,3, and α-1,5 linkages of purified arabinan-oligosaccharides. Furthermore, both CpAbf127A and CpAbf127B cleaved β-arabinofuranose residues in complex arabinan side chains, thus providing evidence of the function of this family of enzymes on such polysaccharides. The optimal temperatures of the enzymes ranged between 60°C and 75°C, and CpAbf43A and CpAbf51A worked synergistically to release arabinose from branched and debranched arabinan. Furthermore, the hydrolytic activity on branched arabinan oligosaccharides and degradation of pectic substrates by the endoarabinanase and l-arabinofuranosidases suggested a microbe equipped with diverse activities to degrade complex arabinan in the environment. Based on our functional analyses of the genes in the arabinan degradation cluster and the substrate-binding studies on a component of the cognate transporter system, we propose a model for arabinan degradation and transport by C. polysaccharolyticus IMPORTANCE Genomic DNA sequencing and

Sugar composition of the pectic polysaccharides of charophytes, the closest algal relatives of land-plants: presence of 3-O-methyl-D-galactose residues.

Science.gov (United States)

O'Rourke, Christina; Gregson, Timothy; Murray, Lorna; Sadler, Ian H; Fry, Stephen C

2015-08-01

During evolution, plants have acquired and/or lost diverse sugar residues as cell-wall constituents. Of particular interest are primordial cell-wall features that existed, and in some cases abruptly changed, during the momentous step whereby land-plants arose from charophytic algal ancestors. Polysaccharides were extracted from four charophyte orders [Chlorokybales (Chlorokybus atmophyticus), Klebsormidiales (Klebsormidium fluitans, K. subtile), Charales (Chara vulgaris, Nitella flexilis), Coleochaetales (Coleochaete scutata)] and an early-diverging land-plant (Anthoceros agrestis). 'Pectins' and 'hemicelluloses', operationally defined as extractable in oxalate (100 °C) and 6 m NaOH (37 °C), respectively, were acid- or Driselase-hydrolysed, and the monosaccharides analysed chromatographically. One unusual monosaccharide, 'U', was characterized by (1)H/(13)C-nuclear magnetic resonance spectroscopy and also enzymically. 'U' was identified as 3-O-methyl-D-galactose (3-MeGal). All pectins, except in Klebsormidium, contained acid- and Driselase-releasable galacturonate, suggesting homogalacturonan. All pectins, without exception, released rhamnose and galactose on acid hydrolysis; however, only in 'higher' charophytes (Charales, Coleochaetales) and Anthoceros were these sugars also efficiently released by Driselase, suggesting rhamnogalacturonan-I. Pectins of 'higher' charophytes, especially Chara, contained little arabinose, instead possessing 3-MeGal. Anthoceros hemicelluloses were rich in glucose, xylose, galactose and arabinose (suggesting xyloglucan and arabinoxylan), none of which was consistently present in charophyte hemicelluloses. Homogalacturonan is an ancient streptophyte feature, albeit secondarily lost in Klebsormidium. When conquering the land, the first embryophytes already possessed rhamnogalacturonan-I. In contrast, charophyte and land-plant hemicelluloses differ substantially, indicating major changes during terrestrialization. The presence of 3

Extração e caracterização de xilanas de sabugos de milho Extraction and characterization of xylans from corncobs

Directory of Open Access Journals (Sweden)

Simone S. Silva

1998-06-01

Full Text Available Neste trabalho, duas frações de xilana, denominadas xilana A e xilana B, foram isoladas a partir de sabugos de milho através de três processos diferentes, combinando métodos de extração aquosa, remoção de lipídeos, deslignificação e extração alcalina. Os produtos obtidos durante os processos foram analisados por termogravimetria. A etapa de deslignificação foi responsável por uma acentuada degradação dos polímeros, evidenciada por queda de rendimento e resistência térmica. Os espectros obtidos no infravermelho evidenciaram a ausência de ácidos urônicos na cadeia polimérica. As viscosidades intrínsecas obtidas para a xilana A (56 mL/g e xilana B (75 mL/g associadas aos resultados do infravermelho sugerem um número maior de grupos substituintes, constituídos basicamente por resíduos de L-arabinose, para a xilana B.In this work, two fractions of xylan, named xylan A and xylan B, were isolated from corncobs through three different processes using aqueous extraction, lipid removal, delignification, and alkaline extraction. The products obtained during the processes were analysed by thermogravimetry. The delignification step was responsible for the occurrence of an accentuated polymer degradation, evidenced by yield and thermal resistance decrease. Infrared spectra indicated the absence of uronic acids in the polymeric chains. Intrinsic viscosities obtained for xylan A (56 mL/g and xylan B (75 mL/g, associated to the results from i.r. analysis, suggested a higher number of substituents, basically constituted of L-arabinose residues, in the case of xylan B.

Hydrophilic solute transport across the rat blood-brain barrier

International Nuclear Information System (INIS)

Lucchesi, K.J.

1987-01-01

Brain capillary permeability-surface area products (PS) of hydrophilic solutes ranging in size from 180 to 5,500 Daltons were measured in rats according to the method of Ohno, Pettigrew and Rapoport. The distribution volume of 70 KD dextran at 10 minutes after i.v. injection was also measured to determine the residual volume of blood in brain tissue at the time of sacrifice. Small test solutes were injected in pairs in order to elucidate whether their transfer into the brain proceeds by diffusion through water- or lipid-filled channels or by vesicular transport. This issue was examined in rats whose blood-brain barrier (BBB) was presumed to be intact (untreated) and in rats that received intracarotid infusions to open the BBB (isosmotic salt (ISS) and hyperosmolar arabinose). Ohno PS values of 3 H-inulin and 14 C-L-glucose in untreated rats were found to decrease as the labelling time was lengthened. This was evidence that a rapidly equilibrating compartment exists between blood and brain that renders the Ohno two-compartment model inadequate for computing true transfer rate constants. When the data were reanalyzed using a multi-compartment graphical analysis, solutes with different molecular radii were found to enter the brain at approximately equal rates. Furthermore, unidirectional transport is likely to be initiated by solute adsorption to a glycocalyx coat on the luminal surface of brain capillary endothelium. Apparently, more inulin than L-glucose was adsorbed, which may account for its slightly faster transfer across the BBB. After rats were treated with intracarotid infusions of ISS or hyperosmolar arabinose, solute PS values were significantly increased, but the ratio of PS for each of the solute pairs approached that of their free-diffusion coefficients

Development of a new fluorescent reporter:operator system: location of AraC regulated genes in Escherichia coli K-12.

Science.gov (United States)

Sellars, Laura E; Bryant, Jack A; Sánchez-Romero, María-Antonia; Sánchez-Morán, Eugenio; Busby, Stephen J W; Lee, David J

2017-08-03

In bacteria, many transcription activator and repressor proteins regulate multiple transcription units that are often distally distributed on the bacterial genome. To investigate the subcellular location of DNA bound proteins in the folded bacterial nucleoid, fluorescent reporters have been developed which can be targeted to specific DNA operator sites. Such Fluorescent Reporter-Operator System (FROS) probes consist of a fluorescent protein fused to a DNA binding protein, which binds to an array of DNA operator sites located within the genome. Here we have developed a new FROS probe using the Escherichia coli MalI transcription factor, fused to mCherry fluorescent protein. We have used this in combination with a LacI repressor::GFP protein based FROS probe to assess the cellular location of commonly regulated transcription units that are distal on the Escherichia coli genome. We developed a new DNA binding fluorescent reporter, consisting of the Escherichia coli MalI protein fused to the mCherry fluorescent protein. This was used in combination with a Lac repressor:green fluorescent protein fusion to examine the spatial positioning and possible co-localisation of target genes, regulated by the Escherichia coli AraC protein. We report that induction of gene expression with arabinose does not result in co-localisation of AraC-regulated transcription units. However, measurable repositioning was observed when gene expression was induced at the AraC-regulated promoter controlling expression of the araFGH genes, located close to the DNA replication terminus on the chromosome. Moreover, in dividing cells, arabinose-induced expression at the araFGH locus enhanced chromosome segregation after replication. Regions of the chromosome regulated by AraC do not colocalise, but transcription events can induce movement of chromosome loci in bacteria and our observations suggest a role for gene expression in chromosome segregation.

Quantification of solubilized hemicellulose from pretreated lignocellulose by acid hydrolysis and high-performance liquid chromatography

Energy Technology Data Exchange (ETDEWEB)

Bjerre, A.B.; Ploeger, A.; Simonsen, T.; Woidemann, A.; Schmidt, A.S.

1996-11-01

An investigation of the acid hydrolysis and HPLC analysis have been carried out in order to optimise the quantification of the solubilized hemicellulose fraction from wheat straw lignocellulose after pretreatment. Different acid hydrolyses have been performed to identify which conditions (concentrations of acid and hydrolysis time) gave the maximal quantification of the solubilized hemicellulose (measured as monosaccharides). Four different sugars were identified: xylose, arabinose, glucose and galactose. Some hydrolyses were carried out on aqueous samples and some using freeze-dried samples. The best overall hydrolysis was obtained by treatment of an aqueous sample with 4 %w/v sulfuric acid for 10 minutes. These conditions were not optimal for the determination of glucose, which was estimated by using a correction factor. A purification step was needed following the acid hydrolysis, and included a sulfate precipitation by barium hydroxide and elimination of remaining ions by mixed-bed ion exchange. The level of barium hydroxide addition significantly reduced the recovery of the sugars. Thus, lower than equivalent amounts of barium hydroxide were added in the purification step. For monosaccharide analysis two different HPLC columns, i.e. Aminex HPX-87P and HPX-87H with different resin ionic forms, lead (Pb{sup 2+}) and hydrogen (H{sup +}), respectively. The lead column (HPX-87P) separated all four sugars in the acid hydrolyzates, but sample purification required the removal of all interfering impurities, which resulted in poor reproducibility and a sugar recovery below 50%. The hydrogen column (HPX-87H) separated only glucose, xylose and arabinose, whereas galactose was not separated from xylose; however, the column was less sensitive towards impurities and gave improved recovery and reproducibility. Therefore, the hydrogen column (HPX-87H) was chosen for routine quantification of the hydrolyzed hemicellulose sugars. (au) 11 tabs., 8 ills., 19 refs.

The use of thermostable bacterial hemicellulases improves the conversion of lignocellulosic biomass to valuable molecules.

Science.gov (United States)

Rakotoarivonina, Harivony; Revol, Pierre-Vincent; Aubry, Nathalie; Rémond, Caroline

2016-09-01

The hydrolysis of xylans, one of the main classes of carbohydrates that constitute lignocellulosic biomass, requires the synergistic action of several enzymes. The development of efficient enzymatic strategies for hydrolysis remains a challenge in the pursuit of viable biorefineries, particularly with respect to the valorisation of pentoses. The approach developed in this work is based on obtaining and characterising hemicellulasic cocktails from Thermobacillus xylanilyticus after culturing this bacterium on the hemicellulose-rich substrates wheat bran and wheat straw, which differ in their chemistries. The two obtained cocktails (WSC and WBC, for cocktails obtained from wheat straw and wheat bran, respectively) were resistant to a broad range of temperature and pH conditions. At 60 °C, both cocktails efficiently liberated pentoses and phenolic acids from wheat bran (liberating more than 60, 30 and 40 % of the total xylose, arabinose and ferulic acid in wheat bran, respectively). They acted to a lesser extent on the more recalcitrant wheat straw, with hydrolytic yields of more than 30 % of the total arabinose and xylose content and 22 % of the ferulic acid content. Hydrolysis is associated with a high rate of sugar monomerisation. When associated with cellulases, high quantities of glucose were also obtained. On wheat bran, total glucose yields were improved by 70 % compared to the action of cellulases alone. This improvement was obtained by cellulase complementation either with WSC or with WBC. On wheat straw, similar levels of total glucose were obtained for cellulases alone or complemented with WSC or WBC. Interestingly, the complementation of cellulases with WSC or WBC induced an increase in the monomeric glucose yield of more than 20 % compared to cellulases alone.

Purification of extensin from cell walls of tomato (hybrid of Lycopersicon esculentum and L. peruvianum) cells in suspension culture.

Science.gov (United States)

Brownleader, M D; Dey, P M

1993-01-01

Extensin, a hydroxyproline-rich glycoprotein comprising substantial amounts of beta-L-arabinose-hydroxyproline glycosidic linkages is believed to be insolubilized in the cell wall during host-pathogen interaction by a peroxidase/hydroperoxide-mediated cross-linking process. Both extensin precursor and extensin peroxidase were ionically eluted from intact water-washed tomato (hybrid of Lycopersicon esculentum Mill. and L. peruvianum L. (Mill.) cells in suspension cultures and purified to homogeneity by a rapid and simple procedure under mild and non-destructive experimental conditions. The molecular weight of native extensin precursor was estimated to be greater than 240-300 kDa by Superose-12 gel-filtration chromatography. Extensin monomers have previously been designated a molecular weight of approximately 80 kDa. Our results indicate that salt-eluted extensin precursor is not monomeric. Agarose-gel electrophoresis, Superose-12-gel-filtration, extensin-peroxidase-catalysed cross-linking, Mono-S ion-exchange fast protein liquid chromatography (FPLC), and peptide-sequencing data confirmed the homogeneity of the extensin preparation. Evidence that the purified protein was extensin is attributed to the presence of the putative sequence motif--Ser (Hyp)4--within the N-terminal end of the protein. Treatment of extensin with trifluoroacetic acid demonstrated that arabinose was the principal carbohydrate. The amino-acid composition of the purified extensin was similar to those reported in the literature. The cross-linking of extensin in vitro upon incubation with extensin peroxidase and exogenous H2O2 was characteristic of other reported extensins. Furthermore, Mono-S ion-exchange FPLC of native extensin precursor resolved it into two isoforms, A (90%) and B (10%). The amino-acid compositions of extensin A and extensin B were found to be similar to each other and both extensins were cross-linked in vitro by extensin peroxidase.

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

Energy Technology Data Exchange (ETDEWEB)

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.

Effects of temperature, pH and carbon and nitrogen sources on growth of in vitro cultures of ectomycorrhizal isolates from Pinus heldreichii forest

Energy Technology Data Exchange (ETDEWEB)

Lazarević, J.; Stojičić, D.; Keča, N.

2016-07-01

Aim of study: This study aims to provide basic information about physiological characteristics of isolates of Lactarius deliciosus (L.) Gray, Russula sanguinaria (Schumach.) Rauschert, Suillus collinitus (Fr) Kuntze, Suillus granulatus (L.) Rousell, Tricholoma batchii Gulden and Tricholoma imbricatum (Fr.) Kumm. Area of study: The isolates are obtained from Pinus heldreichii H. Christ forest in the south-eastern part of Montenegro. Material and methods: The isolates were molecularly characterised by internal transcribed spacer (ITS) sequencing and restriction fragment length polymorphism (RFLP) analysis. The effects of different temperatures (20, 22, 25°C), pHs (4, 4.5, 5.2, 5.8, 6.5, 7.5), and carbon (glucose, sucrose, dextrin, arabinose, xylose and starch) and nitrogen (NH4+, NO3- and protein) sources on their growth were examined under laboratory conditions. Main results: The studied factors established significant differences in the development of isolates. Isolates of R. sanguinaria, L. deliciosus and both Suillus, were characterised by faster growth at 22°C, while Tricholoma isolates grew faster at 25°C. S. granulatus, S. collinitus and T. imbticatum isolates grew well at lower pH values (4 - 5.2), while L. deliciosus, R. sanguinaria and T. bachii exhibited faster growth at pHs between 5.8 and 6.5. The examined isolates were able to utilize various carbohydrates as carbon sources. The biggest mycelial growth was characterised for sucrose, then glucose, dextrin, arabinose, starch and xylose. They grew on all examined nitrogen sources, while the biggest mycelia growth was achieved on ammonium, followed by nitrate and protein. Those characteristics varied amongst the species. Research highlights: Information about physiological characteristics of Tricholoma, Lactarius, Russula, as well as Suillus, are sparse. Hence, the data obtained in this study could contribute to the understanding of their function in ecosystems. (Author)

Expression and purification of recombinant truncated human keratinocyte growth factor-1

International Nuclear Information System (INIS)

Deng Lin; Ma Jisheng; Liu Xiaoju; Wang Xiaojie; Li Xiaokun; Gong Shouliang; Wang Huiyan; Tian Haishan

2010-01-01

Objective: To construct the genetic engineering bacteria highly expressing 23 amino acids human keratinocyte growth factor-1 (rhKGF1 dest23 ) missing N terminal, and provide experimental data for development of new drug for treatment of oral mucositis after radiotherapy and chemotherapy. Methods: PCR was used to synthese 23 amino acids rhKGF1 dest23 missing N terminal and sumo gene fragments, and construct four kinds of recombinant prokaryotic expression vectors: pET22b-rhKGF1 dest23 , pET22b-sumo-rhKGF1 dest23 , pET3c-rhKGF1 dest23 and pET3c-sumo-rhKGF1 dest23 , then they were transformed into prokaryotic expression host bacteria: Rosetta (DE3) plysS, BL21 (DE3), BL21 (DE3) Star plysS, origima(DE3) and BL21AI, the best expression combination of plasmid and host strain of rhKGF1 dest23 protein was screened and purified by CM ion-exchange and heparin affinity chromatography and identified with Western blotting. Results: pET22b-rhKGF1 dest23 plasmid and the BL21AI host bacteria was the best combination of expression, after induced by IPTG and arabinose, the majority of recombinant protein was expressed in soluble form, accounting for about 12% of the total bacterial proteins. Its purity reached to more than 95% of the protein after two steps chromatography, then conformed with Western blotting. Conclusion: Human genetic engineering bacteria of KGF1 dest23 is successfully constructed and induced by IPTG and arabinose, then after CM weak cation exchange and heparin affinity chromatography, the purified rhKGF1 dest23 protein is obtained. (authors)

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

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.

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

2010-01-01

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 ΔasdA allele in live recombinant attenuated Salmonella vaccines (RASVs) such as Salmonella enterica serovar Typhimurium strain χ9447. 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/Pcro) (PR), which is negatively regulated by an arabinose-inducible P22 c2 gene located on both the plasmid and the chromosome (araC PBAD 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 β-lactamase, and cloned into pYA4534 under the control of the Ptrc promoter to generate plasmid pYA4535. Our results indicate that the live Salmonella vaccine strain χ9447 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. PMID:20308296

Study of radiation-destroyed wood

International Nuclear Information System (INIS)

Klimentov, A.S.; Shakhanova, R.K.; Stepanova, I.N.; Vysotskaya, I.F.

1986-01-01

The change in carbohydrate composition of aspen wood exposed to electron beam radiation (0.5 MeV, dose rates of 0-0.56 MGy) is studied. It has been found that the water-soluble polysaccharide content grows from 0.47 up to 8.54 %, and that of the non-hydrolyzed polysaccharides decreases from 49.4 down to 36.1 %. The polysaccharide total content of aspen wood goes down from 61.28 to 56.82 % with the radiation dose increasing. Consequently, the xylose, arabinose, and ramnose percentage of wood hydrolyzates increases correspondingly from 11.9 up to 15.44, from 0.66 up to 0.90, and from 0.21 up to 0.38

Draft genome sequence of Microbacterium oleivorans strain Wellendorf implicates heterotrophic versatility and bioremediation potential

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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.

Kinetic study of dilute nitric acid treatment of corn stover at relatively high temperature

Energy Technology Data Exchange (ETDEWEB)

Zhang, R.; Lu, X.; Liu, Y.; Wang, X.; Zhang, S. [Tianjin University, School of Environmental Science and Technology, Tianjin (China)

2011-03-15

Corn stover was hydrolyzed using dilute nitric acid at 150 C. Several concentrations of HNO{sub 3} (0.2, 0.4 and 0.6 wt-%) and reaction times (0-60 min) were evaluated. The kinetic parameters of mathematical models for predicting the concentrations of xylose, glucose, arabinose, acetic acid, and furfural in the hydrolysates were determined. The hydrolysates obtained from corn stover can be used to produce methane by an anaerobic fermentation process. Thus, the hydrolysis process of corn stover using dilute nitric acid can be conceived as the first stage of an integrated strategy for corn stover utilization. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

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...

Antioxidant and antibacterial activities of polysaccharides isolated and purified from Diaphragma juglandis fructus.

Science.gov (United States)

Meng, Qingran; Li, Yinghao; Xiao, Tiancun; Zhang, Lianfu; Xu, Dan

2017-12-01

A water-soluble polysaccharide fraction (DJP-2) isolated from Diaphragma juglandis was successfully purified by ion-exchange chromatography (DEAE-cellulose) and gel-permeation chromatography (Sephadex G-100). The weight-average molecular weight (Mw) and number-average molecular weight (Mn) of DJP-2 were 4.95 and 3.99kDa, respectively. Monosaccharide component analysis indicated that DJP-2 comprised arabinose, galactose, glucose, xylose, and mannose in a molar ratio of 0.27:0.55:1:0.14:0.08. The evaluation of the antioxidant and antibacterial activities of polysaccharides from Diaphragma juglandis fructus indicated that they could be explored as promising natural antioxidant and bacteriostatic agents in the food and pharmaceutical industries. Copyright © 2017 Elsevier B.V. All rights reserved.

Rapid near infrared spectroscopy for prediction of enzymatic hydrolysis of corn bran after various pretreatments

DEFF Research Database (Denmark)

Baum, Andreas; Wittrup Agger, Jane; Meyer, Anne S.

2012-01-01

Efficient generation of a fermentable hydrolysate is a primary requirement in the utilization of fibrous plant biomass as feedstocks in bioethanol processes. The first biomass conversion step usually involves a hydrothermal pretreatment before enzymatic hydrolysis. The purpose of the pretreatment...... step is to increase the responsivity of the substrate to enzymatic attack and the type of pretreatment affects the enzymatic conversion efficiency. Destarched corn bran is a fibrous, heteroxylan-rich side-stream from the starch industry which may be used as a feedstock for bioethanol production...... release of different levels of arabinose, xylose and glucose from all the differently pretreated destarched corn bran samples. The present study also demonstrates a generic, non-destructive solution to determine the enzymatic monosaccharide release from polymers in biomass side-streams, thereby...

Trapped electrons in irradiated single crystals of polyhydroxy compounds

International Nuclear Information System (INIS)

Box, H.C.; Budzinski, E.E.; Freund, H.G.; Potter, W.R.

1979-01-01

The intermolecular trapping of electrons has been observed in single crystals of dulcitol and L(+) arabinose x-irradiated at 4.2 0 K. Attribution of a major component of the ESR absorption to trapped electrons is based upon the character of the hyperfine pattern, which arises from multiple anisotropic hyperfine interactions with exchangeable protons, and on the g value of the absorption, which is always less than the free spin value. The removal of the trapped electron absorption upon irradiation with visible light has also been demonstrated. In these experiments all of the electrons are trapped in identical sites. This circumstance provides some important advantages in the study of the factors affecting the stabilization of charge in an environment of polarizable molecules

Total recovery of the waste of two-phase olive oil processing: isolation of added-value compounds.

Science.gov (United States)

Fernández-Bolaños, Juan; Rodríguez, Guillermo; Gómez, Esther; Guillén, Rafael; Jiménez, Ana; Heredia, Antonia; Rodríguez, Rocío

2004-09-22

A process for the value addition of solid waste from two-phase olive oil extraction or "alperujo" that includes a hydrothermal treatment has been suggested. In this treatment an autohydrolysis process occurs and the solid olive byproduct is partially solubilized. From this water-soluble fraction can be obtained besides the antioxidant hydroxytyrosol several other compounds of high added value. In this paper three different samples of alperujo were characterized and subjected to a hydrothermal treatment with and without acid catalyst. The main soluble compounds after the hydrolysis were represented by monosaccharides xylose, arabinose, and glucose; oligosaccharides, mannitol and products of sugar destruction. Oligosaccharides were separated by size exclusion chromatography. It was possible to get highly purified mannitol by applying a simple purification method.

Xylanase production by Trichoderma longibrachiatum

Energy Technology Data Exchange (ETDEWEB)

Royer, J C; Nakas, J P [State Univ. of New York, Syracuse, NY (USA). Coll. of Environmental Science and Forestry

1989-07-01

Xylan comprises up to 25% of hardwood biomass and is found in a variety of agricultural residues. It therefore represents a significant renewable resource which should be utilized to improve the economics of bioconversion of plant biomass to useful products. Before fermentation to fuels or solvents, xylan must be hydrolysed to xylose or short-chain oligomers of xylose. The effects of carbon source, substrate concentration, culture pH, and spore inoculum concentration on production of extracellular xylanase and cellulase were examined. Very low enzyme activities were obtained with growth on glucose, xylose, and cellobiose, while significantly higher levels were produced from lactose and arabinose. Higher levels of both enzymes were generated from alpha cellulose, wood pulp, and fibrous paper waste than from purified xylan. (author).

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.

Cathode Assessment for Maximizing Current Generation in Microbial Fuel Cells Utilizing Bioethanol Effluent as Substrate

DEFF Research Database (Denmark)

Sun, Guotao; Thygesen, Anders; Meyer, Anne S.

2016-01-01

Implementation of microbial fuel cells (MFCs) for electricity production requires effective current generation from waste products via robust cathode reduction. Three cathode types using dissolved oxygen cathodes (DOCs), ferricyanide cathodes (FeCs) and air cathodes (AiCs) were therefore assessed...... to be the most sustainable option since it does not require ferricyanide. The data offer a new add-on option to the straw biorefinery by using bioethanol effluent for microbial electricity production....... using bioethanol effluent, containing 20.5 g/L xylose, 1.8 g/L arabinose and 2.5 g/L propionic acid. In each set-up the anode and cathode had an electrode surface area of 88 cm(2), which was used for calculation of the current density. Electricity generation was evaluated by quantifying current...

Furfural Production from d-Xylose and Xylan by Using Stable Nafion NR50 and NaCl in a Microwave-Assisted Biphasic Reaction

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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.

Furfural Production from d-Xylose and Xylan by Using Stable Nafion NR50 and NaCl in a Microwave-Assisted Biphasic Reaction.

Science.gov (United States)

Le Guenic, Sarah; Gergela, David; Ceballos, Claire; Delbecq, Frederic; Len, Christophe

2016-08-22

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.

New and convenient synthesis of 2-deoxy-D-ribose from 2,4-O-ethylidene-D-erythrose

Energy Technology Data Exchange (ETDEWEB)

Hauske, J.R.; Rapoport, H.

1979-01-01

A new synthesis is described of 2-deoxy-D-erythro-pentose (2-deoxy-D-ribose,2-deoxy-D-arabinose (1)), starting from D-glucose. The synthesis proceeds through direct olefination of 2,4-O-ethylidene-D-erythrose (2) by addition of the stabilized ylides generated from dimethylphosphorylmethyl phenyl sulfide (4) and the corresponding sulfoxide 5. These afford the key intermediates, thio-enol ether 7 and ..cap alpha..,..beta..-unsaturated sulfoxide 8, which when subjected to mercuric ion assisted hydrolysis gave high yields of 2-deoxy-D-ribose (1). This facile chain extension of 2 required its existance as a monomer, and conditions effective for obtaining the monomer have been developed. Detailed /sup 1/H and /sup 13/C NMR studies of these compounds are presented.

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

Despite major progresses in genetic studies of hyperthermophilic archaea, recombinant protein production in these organisms always suffers from low yields and a robust expression system is still in great demand. Here we report a versatile vector that confers high levels of protein expression...... to remove the peptide tags from expressed recombinant proteins. While pEXA employed an araS promoter for protein expression, pSeSD utilized P(araS-SD), an araS derivative promoter carrying an engineered ribosome-binding site (RBS; a Shine-Dalgarno [SD] sequence). We found that P(araS-SD) directed high...... 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...

Pectic polysaccharide from corn (Zea mays L.) effectively inhibited multi-step mediated cancer cell growth and metastasis.

Science.gov (United States)

Jayaram, Smitha; Kapoor, Sabeeta; Dharmesh, Shylaja M

2015-06-25

Corn pectic polysaccharide (COPP) inhibited galectin-3 mediated hemagglutination at Minimum Inhibitory Concentration (MIC) of 4.08 μg/mL as opposed to citrus pectin (25 μg/mL), a well known galectin-3 inhibitor and lactose (4.16 μg/mL)--sugar specific to galectin-3. COPP effectively (72%) inhibited invasion and metastasis in experimental animals. In vivo results were substantiated by modulation of cancer specific markers such as galectin-3, which is a key molecule for initiation of metastatic cascade, vascular endothelial growth factor (VEGF) that enhances angiogenesis, matrix metalloproteinases 2 and 9 that are required for invasion, NF-κB, a transcription factor for proliferative potency of tumor cells and a phosphoglucoisomerase (PGI), the activity of which favors cancer cell growth. Structural characterization studies indicate the active component (relatively less acidic, 0.05 M ammonium carbonate, 160 kDa fraction) which showed antimetastatic potency in vitro with MIC of 0.09 μg/mL, and ∼ 45 fold increase in the activity when compared to that of COPP. Gas liquid chromatographic analysis indicated the presence of rhamnose (1%), arabinose (20%), xylose (3%), mannose (4%), galactose (54%) and uronic acid (10%) in different proportions. However, correlative data attributed galectin-3 inhibitory activity to enhanced levels of arabinose and galactose. FTIR, HPLC and NMR spectroscopic analysis further highlights that COPP is an arabinogalactan with methyl/ethyl esters. It is therefore suggested that the blockade of galectin-3 mediated lung metastasis appears to be a result of an inhibition of mixed functions induced during metastasis. The data signifies the importance of dietary carbohydrate as cancer-preventive agent. Although pectin digestibility and absorption are issues of concern, promising in vivo data provides evidence for the cancer preventive property of corn. The present study reveals for the first time a new component of corn, i.e.,--corn pectin

Universal platform for quantitative analysis of DNA transposition

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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

Xylitol production from xylose mother liquor: a novel strategy that combines the use of recombinant Bacillus subtilis and Candida maltosa

Science.gov (United States)

2011-01-01

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-mediated biohydrogenation of xylose

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

Competition between pentoses and glucose during uptake and catabolism in recombinant Saccharomyces cerevisiae

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Subtil Thorsten

2012-03-01

Full Text Available Abstract Background In mixed sugar fermentations with recombinant Saccharomyces cerevisiae strains able to ferment D-xylose and L-arabinose the pentose sugars are normally only utilized after depletion of D-glucose. This has been attributed to competitive inhibition of pentose uptake by D-glucose as pentose sugars are taken up into yeast cells by individual members of the yeast hexose transporter family. We wanted to investigate whether D-glucose inhibits pentose utilization only by blocking its uptake or also by interfering with its further metabolism. Results To distinguish between inhibitory effects of D-glucose on pentose uptake and pentose catabolism, maltose was used as an alternative carbon source in maltose-pentose co-consumption experiments. Maltose is taken up by a specific maltose transport system and hydrolyzed only intracellularly into two D-glucose molecules. Pentose consumption decreased by about 20 - 30% during the simultaneous utilization of maltose indicating that hexose catabolism can impede pentose utilization. To test whether intracellular D-glucose might impair pentose utilization, hexo-/glucokinase deletion mutants were constructed. Those mutants are known to accumulate intracellular D-glucose when incubated with maltose. However, pentose utilization was not effected in the presence of maltose. Addition of increasing concentrations of D-glucose to the hexo-/glucokinase mutants finally completely blocked D-xylose as well as L-arabinose consumption, indicating a pronounced inhibitory effect of D-glucose on pentose uptake. Nevertheless, constitutive overexpression of pentose-transporting hexose transporters like Hxt7 and Gal2 could improve pentose consumption in the presence of D-glucose. Conclusion Our results confirm that D-glucose impairs the simultaneous utilization of pentoses mainly due to inhibition of pentose uptake. Whereas intracellular D-glucose does not seem to have an inhibitory effect on pentose utilization

Hydrothermal pentose to furfural conversion and simultaneous extraction with SC-CO2--kinetics and application to biomass hydrolysates.

Science.gov (United States)

Gairola, Krishan; Smirnova, Irina

2012-11-01

This work explores hydrothermal d-xylose and hemicellulose to furfural conversion coupled with simultaneous furfural extraction by SC-CO(2) and the underlying reaction pathway. A maximum furfural yield of 68% was attained from d-xylose at 230°C and 12MPa. Additionally missing kinetic data for l-arabinose to furfural conversion was provided, showing close similarity to d-xylose. Furfural yields from straw and brewery waste hydrolysates were significantly lower than those obtained from model compounds, indicating side reactions with other hydrolysate components. Simultaneous furfural extraction by SC-CO(2) significantly increased extraction yield in all cases. The results indicate that furfural reacts with intermediates of pentose dehydration. The proposed processing route can be well integrated into existing lignocellulose biorefinery concepts. Copyright © 2012 Elsevier Ltd. All rights reserved.

Extraction, purification and antioxidant activities of the polysaccharides from maca (Lepidium meyenii).

Science.gov (United States)

Zha, Shenghua; Zhao, Qingsheng; Chen, Jinjin; Wang, Liwei; Zhang, Guifeng; Zhang, Hong; Zhao, Bing

2014-10-13

Water-soluble polysaccharides were separated from maca (Lepidium meyenii) aqueous extract (MAE). The crude polysaccharides were deproteinized by Sevag method. During the preparation process of maca polysaccharides, amylase and glucoamylase effectively removed starch in maca polysaccharides. Four Lepidium meyenii polysaccharides (LMPs) were obtained by changing the concentration of ethanol in the process of polysaccharide precipitation. All of the LMPs were composed of rhamnose, arabinose, glucose and galactose. Antioxidant activity tests revealed that LMP-60 showed good capability of scavenging hydroxyl free radical and superoxide radical at 2.0mg/mL, the scavenging rate was 52.9% and 85.8%, respectively. Therefore, the results showed that maca polysaccharides had a high antioxidant activity and could be explored as the source of bioactive compounds. Copyright © 2014 Elsevier Ltd. All rights reserved.

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

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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.

Synthesis, spectroscopic and biological studies of transition metal complexes of novel schiff bases derived from cephradine and sugars

International Nuclear Information System (INIS)

Naz, N.; Iqbal, M.Z.

2011-01-01

Fe(II), Co(II) and Ni(II) metal complexes of novel schiff bases derived from Cephradine and sugars (D-Glucose, L. Arabinose and D-Galactose) were synthesized and characterized by elemental analysis, magnetic susceptibility, thermal analysis, electronic absorption and FT-IR spectral studies. It has been found that schiff bases behave as bi-dentate-ligands forming complexes with 1:2 (metal:ligand) stoichiometry. the neutral nature of the complexes was confirmed by their low conductance values. The biological activities of complexes have been evaluated against two gram negative (Escherichia coli and Pseudomonas aeruginosa) and two gram positive (Bacillus subtilis and staphylococcus aureus) bacteria by Agar diffusion disc method. It has been found that the complexes have higher activity as compared to the pure Cephradine against the same bacteria. (author)

Thermostable amylolytic enzymes from a cellulolytic fungus Myceliophthora thermophila D14 (ATCC 48 104)

Energy Technology Data Exchange (ETDEWEB)

Sadhukhan, R K; Manna, S; Roy, S K; Chakrabarty, S L [Bose Research Inst., Calcutta (India). Dept. of Microbiology

1990-09-01

The production of amylolytic enzymes by a thermophilic cellulolytic fungus, Myceliophthora thermophila D14 was investigated by batch cultivation in Czapek-Dox medium at 45deg C. Among various nitrogenous compounds used, NaNO{sub 3} and KNO{sub 3} were found to be the best for amylase production. Starch, cellobiose and maltose induced the synthesis of amylase while glucose, fructose, galactose, lactose, arabinose, xylose, sorbitol, mesoinositol and sucrose did not. Calcium ions had the most stimulating effect on enzyme formation amongst many ions investigated. The synthesis of amylolytic enzymes was dependent on growth and occurred predominantly in the mid-stationary phase. The enzyme was active in a broad temperature range (50deg C-60deg C) and displayed activity optima at 60deg C and pH 5.6. (orig.).

γ radiation dosimetry in Mega rad range using sugar solution

International Nuclear Information System (INIS)

Venkataramani, R.; Mehta, S.K.; Soman, S.D.

1976-01-01

The formation of malonaldehyde under γ irradiation of solid sucrose and aqueous sucrose, fructose and arabinose solutions has been studied in the Mega rad range. Malonaldehyde (MA) concentration was estimated spectrophotometrically after complexing with 2-thio-barbituric acid. The effect of free radical scavengers (KI and N 2 O) on the yield of MA was investigated. Of the systems studied a 5% aqueous sucrose solution gave a proportional response of MA formation with dose in 0.2 to 5 Mega rad range. A 5% aqueous solution of sucrose prepared from sucrose irradiated in solid state also gave a smooth response of MA yield with dose from 8 to 30 Mega rad. The aqueous and solid sucrose systems together can be conveniently used for dosimetry in the range of 0.2 30 Mega rad. (author)

Characterization of Eubacterium coprostanoligenes sp. nov., a cholesterol-reducing anaerobe.

Science.gov (United States)

Freier, T A; Beitz, D C; Li, L; Hartman, P A

1994-01-01

A small, anaerobic, gram-positive coccobacillus that reduces cholesterol to coprostanol was isolated from a hog sewage lagoon. This isolate, strain HLT (T = type strain) does not require cholesterol for growth, but it requires lecithin and has phospholipase activity. Much acid is produced by the fermentation of amygdalin, lactose, and salicin. Arabinose, cellobiose, fructose, glucose, mannose, and melibiose are fermented weakly. Acetic, formic, and succinic acids are produced, as is hydrogen. The isolate does not reduce nitrate, produce indole, or hydrolyze starch and gelatin. Esculin is hydrolyzed. The properties of strain HLT are most similar to those of members of the genus Eubacterium. Because strain HL (= ATCC 51222) has unique morphological and physiological properties, we propose that it should be the type strain of a new species in the genus Eubacterium, Eubacterium coprostanoligenes.

gamma. radiation dosimetry in Mega rad range using sugar solution

Energy Technology Data Exchange (ETDEWEB)

Venkataramani, R; Mehta, S K; Soman, S D [Bhabha Atomic Research Centre, Bombay (India). Health Physics Div.

1976-09-01

The formation of malonaldehyde under ..gamma.. irradiation of solid sucrose and aqueous sucrose, fructose and arabinose solutions has been studied in the Mega rad range. Malonaldehyde (MA) concentration was estimated spectrophotometrically after complexing with 2-thio-barbituric acid. The effect of free radical scavengers (KI and N/sub 2/O) on the yield of MA was investigated. Of the systems studied a 5% aqueous sucrose solution gave a proportional response of MA formation with dose in 0.2 to 5 Mega rad range. A 5% aqueous solution of sucrose prepared from sucrose irradiated in solid state also gave a smooth response of MA yield with dose from 8 to 30 Mega rad. The aqueous and solid sucrose systems together can be conveniently used for dosimetry in the range of 0.2 30 Mega rad.

Theoretical study on the factors controlling the stability of the borate complexes of ribose, arabinose, lyxose, and xylose

Czech Academy of Sciences Publication Activity Database

Šponer, Judit E.; Sumpter, B.G.; Leszczynski, J.; Šponer, Jiří; Fuentes-Cabrera, M.

2008-01-01

Roč. 14, č. 32 (2008), s. 9990-9998 ISSN 0947-6539 R&D Projects: GA AV ČR(CZ) IAA400550701; GA AV ČR(CZ) IAA400040802; GA AV ČR(CZ) 1QS500040581; GA MŠk(CZ) LC06030 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : borates * density functional calculations * carbohydrates Subject RIV: AQ - Safety, Health Protection, Human - Machine Impact factor: 5.454, year: 2008

Polysaccharide fraction from higher plants which strongly interacts with the cytosolic phosphorylase isozyme. I. Isolation and characterization

International Nuclear Information System (INIS)

Yang, Yi; Steup, M.

1990-01-01

From leaves of Spinacia oleracea L. or from Pisum sativum L. and from cotyledons of germinating pea seeds a high molecular weight polysaccharide fraction was isolated. The apparent size of the fraction, as determined by gel filtration, was similar to that of dextran blue. Following acid hydrolysis the monomer content of the polysaccharide preparation was studied using high pressure liquid and thin layer chromatography. Glucose, galactose, arabinose, and ribose were the main monosaccharide compounds. The native polysaccharide preparation interacted strongly with the cytosolic isozyme of phosphorylase (EC 2.4.1.1). Interaction with the plastidic phosphorylase isozyme(s) was by far weaker. Interaction with the cytosolic isozyme was demonstrated by affinity electrophoresis, kinetic measurements, and by 14 C-labeling experiments in which the glucosyl transfer from [ 14 C]glucose 1-phosphate to the polysaccharide preparation was monitored

Enzymatic hydrolysis of corn bran arabinoxylan

DEFF Research Database (Denmark)

Agger, Jane

as a model substrate because it represents a readily available agroindustrial side product with upgrading potentials. Corn bran originates from the wet-milling process in corn starch processing, is the outmost layers of the corn kernel and is particularly rich in pentose monosaccharides comprising the major...... in a complex and ridig cell wall structure. This thesis contains a thorough examination of the monosaccharide and structural composition of corn bran, which is used to assess and apply the relevant mono component enzyme preparations. In this way, the aim is to obtain the most effective minimal enzymatic......, especially with respect to xylose and glucose release, but vast amounts of the valuable monosaccharides are lost during this pretreatment and this is especially evident for arabinose. From a scientific point of view acid catalysed pretreatment renders the substrate in a state of disruption where assessment...

Production and decomposition of new DOC by marine plankton communities: carbohydrates, refractory components and nutrient limitation

DEFF Research Database (Denmark)

Kragh, T.; Søndergaard, Morten

2009-01-01

The accumulation and biodegradation of dissolved organic carbon (DOC) and dissolved and particulate combined neutral sugars (DCNS, PCNS) were followed during a period of 22 days in experimental marine phytoplankton incubations. Five different growth regimes were established in 11 m(3) coastal...... in the mesocosms with diatoms dominating could be explained by DCNS, while only 6% was explained in the mesocosms with few diatoms. PCNS composition was similar in all mesocosms and with dominance of glucose and mannose, while DCNS were more evenly distributed with the following mole percentages fucose 15......, rhamnose 14, arabinose 6, galactose 27, glucose 20 and mannose 18%. The DCNS composition did not reflect the PCNS composition at any time during the experiment. Accumulated DCNS were quickly degraded and only 1% of the new RDOC was explained by DCNS. RDOC accumulated after day #17 in the two mesocosms...

Development of microbial biosensors for food analysis

DEFF Research Database (Denmark)

Lukasiak, Justyna

in order to fulfill the needs of different fields, from environmental sciences to food industry. Moreover, they can be an answer for the need of novel, less expensive and environmentally neutral methods of analysis particularly in food ingredients assessment. The aim of this PhD thesis was to develop...... heteropolysaccharide commonly used in food industry as a gelling agent and food stabilizer. The chemical analysis of the pectin carbohydrate composition is a significant issue during the study of its function and properties. Arabinoxylan is one of the main non-starch polysaccharide derived from the cell wall of cereal...... 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...

Resistant-hemicelluloses toward successive chemical treatment during cellulose fibre extraction

Science.gov (United States)

Naqiya, F. M. Z.; Ahmad, I.; Airianah, O. B.

2018-04-01

Lignocellulosic materials have high demand bio-polymers industries as it is rich in cellulose but other residues that still remain in the extracted cellulose might influence the ability of cellulose-rich material to interact with other polymers. In this study, cellulose fibre was extracted from oil palm frond (OPF) using alkali and bleaching treatment. The morphological changes of each sample after every treatment was observed using Scanning Electron Microscope (SEM) and was further chemically extracted and quantitatively evaluated via spectrophotometric method. The non-cellulosic component was found predominantly contained hemicelluloses and these remaining hemicelluloses were hydrolysed and the monosaccharides of hemicelluloses were visualised by Thin Layer Chromatography (TLC). Xylose, arabinose, mannose and glucose were detected and therefore, it is suggested that the plausible type of resistant-hemicelluloses in OPF extracted fibre are arabinoxylan, glucomannan and/or glucan.

Base catalysed isomerisation of aldoses of the arabino and lyxo series in the presence of aluminate.

Science.gov (United States)

Ekeberg, Dag; Morgenlie, Svein; Stenstrøm, Yngve

2002-04-30

Base-catalysed isomerisation of aldoses of the arabino and lyxo series in aluminate solution has been investigated. L-Arabinose and D-galactose give L-erythro-2-pentulose (L-ribulose) and D-lyxo-2-hexulose (D-tagatose), respectively, in good yields, whereas lower reactivity is observed for 6-deoxy-D-galactose (D-fucose). From D-lyxose, D-mannose and 6-deoxy-L-mannose (L-rhamnose) are obtained mixtures of ketoses and C-2 epimeric aldoses. Small amounts of the 3-epimers of the ketoses were also formed. 6-Deoxy-L-arabino-2-hexulose (6-deoxy-L-fructose) and 6-deoxy-L-glucose (L-quinovose) were formed in low yields from 6-deoxy-L-mannose and isolated as their O-isopropylidene derivatives. Explanations of the differences in reactivity and course of the reaction have been suggested on the basis of steric effects.

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.

Recent advances on the posttranslational modifications of EXTs and their roles in plant cell walls

DEFF Research Database (Denmark)

Velasquez, Melina; Salter, Juan Salgado; Dorosz, Javier Gloazzo

2012-01-01

The genetic set up and the enzymes that define the O-glycosylation sites and transfer the activated sugars to cell wall glycoprotein Extensins (EXTs) have remained unknown for a long time. We are now beginning to see the emerging components of the molecular machinery that assembles these complex O......-glycoproteins on the plant cell wall. Genes conferring the posttranslational modifications, i.e., proline hydroxylation and subsequent O-glycosylation, of the EXTs have been recently identified. In this review we summarize the enzymes that define the O-glycosylation sites on the O-glycoproteins, i.e., the prolyl 4......-hydroxylases (P4Hs), the glycosyltransferases that transfer arabinose units (named arabinosyltransferases, AraTs), and the one responsible for transferring a single galactose (galactosyltransferase, GalT) on the protein EXT backbones. We discuss the effects of posttranslational modifications on the structure...

Radiation and chemical stability of 2-deoxy-2-[18F]fluoro-D-glucose radiopharmaceutical. Author-review of thesis

International Nuclear Information System (INIS)

Buriova, M.

2004-07-01

A qualitative and quantitative analytical technique of low-molecular components of chemical and radiation-chemical decomposition of 2-deoxy-2-[ 18 F]fluoro-D-glucose, 2-[ 18 F]FDG radiopharmaceutical was developed for its extended quality control by HPLC with mass-spectrometric electro-spray ionisation detector (ESI MS). The analysis constituted from the liquid chromatography on silica gel NH 2 bonded column combined with mass-spectrometric, UV-VIS, refraction index and radiometric detectors. A modern LC/MS system (Agilent 1100) was demonstrated to be suitable not only for identification of unknown analytes, but also for complex analysis of solutes except [ 18 F]F - . This was advantageous for the 2-[ 18 F]FDG autoradiolysis assessment about which no data were published. For comparative purposes, were used a classic thin layer chromatography (TLC) on silica gel with mobile phase acetonitril: water at 95:5 v/v, and HPTLC on NH 2 modified silica gel like the LC column. Mobile phase was identical as by LC/MS method (acetonitril: 4 mM aqueous solution of ammonium formate 80:20 v/v). Retention times of reference samples: fluorodeoxyglucose, glucose, mannose, arabinose, deoxyglucose, gluconic and glucuronic acids at HPLC were established. Optimal performance of the ESI MS detector was discovered in negative ions mode or single ion monitoring (SIM) regime. The most intensive signal was observed for all analyte molecules association with formate anion HCOO - and also for negative ions of deprotonised molecules. All acids appeared in the form of their lactones. FDG and Glc exhibited tendency for formation of a mixed associate charged by HCOO - anion. On the amine bond silica gel HPTLC column, FDG is poorly separated from fluoride, which even in presence of Kryptofix 2.2.2 remains on the start like on the silica gel layer. At LC-MS Kryptofix provides a very well measurable signals of associates with NH 4+ a H + ions in positive mode of ESI MS. Concentration of ( 19 F

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

Polyphenolic, polysaccharide and oligosaccharide composition of Tempranillo red wines and their relationship with the perceived astringency.

Science.gov (United States)

Quijada-Morín, Natalia; Williams, Pascale; Rivas-Gonzalo, Julián C; Doco, Thierry; Escribano-Bailón, M Teresa

2014-07-01

The influence of the proanthocyanidic, polysaccharide and oligosaccharide composition on astringency perception of Tempranillo wines has been evaluated. Statistical analyses revealed the existence of relationships between chemical composition and perceived astringency. Proanthocyanidic subunit distribution had the strongest contribution to the multiple linear regression (MLR) model. Polysaccharide families showed clear opposition to astringency perception according to principal component analysis (PCA) results, being stronger for mannoproteins and rhamnogalacturonan-II (RG-II), but only Polysaccharides Rich in Arabinose and Galactose (PRAGs) were considered in the final fitted MLR model, which explained 96.8% of the variability observed in the data. Oligosaccharides did not show a clear opposition, revealing that structure and size of carbohydrates are important for astringency perception. Mannose and galactose residues in the oligosaccharide fraction are positively related to astringency perception, probably because its presence is consequence of the degradation of polysaccharides. Copyright © 2014 Elsevier Ltd. All rights reserved.

Xylanases and Their Applications in Baking Industry

Directory of Open Access Journals (Sweden)

Masood Sadiq Butt

2008-01-01

Full Text Available Xylan is the second most abundant polysaccharide and a major component of plant cell wall. Cereal xylans contain large quantities of L-arabinose and are therefore, often referred to as arabinoxylans. Xylanases are hydrolytic enzymes, which randomly cleave the β-1,4 backbone of this complex plant cell wall polysaccharide. Different species of Aspergillus and Trichoderma produce these enzymes. Xylanases are of great value in baking as they have been found to improve the bread volume, crumb structure and reduce stickiness. When xylanases are used at optimum levels, they play a significant role in increasing shelf life of bread and reduce bread staling. There is an increasing trend in baking industry towards the application of xylanases in bread production. This review discusses the application of xylanase in the bakery industry, alone and in combination with other enzymes when it shows synergism in the action with them.

Incorporation of carbohydrate residues into peroxidase isoenzymes in horseradish roots.

Science.gov (United States)

Lew, J Y; Shannon, L M

1973-11-01

Sliced root tissue of the horseradish plant (Armoracia rusticana), when incubated with mannose-U-(14)C, incorporated radioactivity into peroxidase isoenzymes. Over 90% of the radioactivity in the highly purified peroxidase isoenzymes was present in the neutral sugar residues of the molecule, i.e. fucose, arabinose, xylose, mannose. When the root slices were incubated simultaneously with leucine-4,5-(3)H and mannose-U-(14)C, cycloheximide strongly inhibited leucine incorporation into the peptide portion of peroxidase isoenzymes but had little effect on the incorporation of (14)C into the neutral sugars. These results indicated that synthesis of the peptide portion of peroxidase was completed before the monosaccharide residues were attached to the molecule. This temporal relationship between the synthesis of protein and the attachment of carbohydrate residues in the plant glycoprotein, horseradish peroxidase, appears to be similar to that reported for glycoprotein biosynthesis in many mammalian systems.

Characterization of nonstarch polysaccharides content from different edible organs of some vegetables, determined by GC and HPLC: comparative study.

Science.gov (United States)

Villanueva-Suárez, M J; Redondo-Cuenca, A; Rodríguez-Sevilla, M D; de las Heras Martínez, M

2003-09-24

Content and composition of dietary fiber as nonstarch polysaccharides (NSP) was determined in vegetables belonging to different types of edible organs, using GC and HPLC. Samples analyzed were subterranean organs (radish and leek), leaves (celery, swiss chard, and lettuce), stalks (celery, swiss chard, and asparagus), inflorescence (broccoli), and fruits (tomato, green pepper, and marrow). The results indicate that though the monomeric profile is similar in all these samples quantitative differences were found for neutral sugars and uronic acids among samples of the same type of vegetal organ. The NSP values determined using CG method were in good agreement with HPLC method (R(2) = 0.9005). However, arabinose, mannose, and galactose plus rhamnose are more influenced by the analytical method used than the rest of the monomers in nearly all the samples analyzed. Final values of NSP depend on the method used in celery stalks, broccoli, and green pepper.

Composition of the sheath produced by the green alga Chlorella sorokiniana.

Science.gov (United States)

Watanabe, K; Imase, M; Sasaki, K; Ohmura, N; Saiki, H; Tanaka, H

2006-05-01

To investigate the chemical characterization of the mucilage sheath produced by Chlorella sorokiniana. Algal mucilage sheath was hydrolysed with NaOH, containing EDTA. The purity of the hydrolysed sheath was determined by an ATP assay. The composition of polysaccharide in the sheath was investigated by high-performance anion-exchange chromatography with pulsed amperometric detection. Sucrose, galacturonic acid, xylitol, inositol, ribose, mannose, arabinose, galactose, rhamnose and fructose were detected in the sheath as sugar components. Magnesium was detected in the sheath as a divalent cation using inductively coupled argon plasma. The sheath matrix also contained protein. It appears that the sheath is composed of sugars and metals. Mucilage sheath contains many kinds of saccharides that are produced as photosynthetic metabolites and divalent cations that are contained in the culture medium. This is the first report on chemical characterization of the sheath matrix produced by C. sorokiniana.

Enzyme catalyzed oxidative cross-linking of feruloylated pectic polysaccharides from sugar beet

DEFF Research Database (Denmark)

Abang Zaidel, Dayang Norulfairuz

beet pulp as a potential starting material for production of pectin derived products which could help maintain the competitiveness of the sugar beet based industry. The overall objective of this study has been focusing on understanding the kinetics of enzyme catalyzed oxidative crosslinking......-linked by HRP catalysis in the presence of hydrogen peroxide (H2O2) to form ferulic acid dehydrodimers (diFAs). The composition of the substrate was analyzed by HPAEC, HPLC and MALDI-TOF, confirming the structural make up of the arabinan-oligosaccharide (Arabinose: 2.9- 3.4 mmol?g-1 DM; FA: 2.5-7.0 mg?g-1 DM......, identically composed, oil-in-water emulsion systems to study the effect of different methods of emulsion preparation on the emulsion stability in the presence of SBP and the kinetics of enzyme catalyzed oxidative gelation of SBP. The result shows that the different methods of emulsion preparation affect...

Chemical composition and antioxidant activities in immumosuppressed mice of polysaccharides isolated from Mosla chinensis Maxim cv. jiangxiangru.

Science.gov (United States)

Li, Jing-En; Nie, Shao-Ping; Xie, Ming-Yong; Huang, Dan-Fei; Wang, Yu-Ting; Li, Chang

2013-10-01

Polysaccharide MP was isolated from Mosla chinensis Maxim cv. jiangxiangru. It was composed of rhamnose, arabinose, xylose, mannose, glucose and galactose in a molar ratio of 5.364:12.260:3.448:12.260:32.567:30.651, with 11.00%±0.24% uronic acid and 9.046%±0.04% protein. Its antioxidant activity on the cyclophosphamide-induced immunosuppressed mice was investigated. The spleen and the thymus indices were investigated, and the biochemical parameters were evaluated in three organs (liver, heart and kidney). MP was able to overcome the cyclophosphamide-induced immunosuppression and can significantly raise the T-AOC, CAT, SOD and GSH-PX level. It also raised the spleen and thymus indices and decreased the MDA level in mice. MP could play an important role during the prevention process of oxidative damage in immunological system. Copyright © 2013 Elsevier B.V. All rights reserved.

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...... could be polymerized by laccase and then completely retained by the NF membranes via size exclusion at pH 5.15. The formation of large polymeric products by laccase could alleviate the irreversible fouling in/on a NF membrane and decrease the monosaccharide retention, while the small polymeric products...

Morphological, Cultural, Biochemical, and Serological Comparison of Japanese Strains of Vibrio parahemolyticus with Related Cultures Isolated in the United States

Science.gov (United States)

Twedt, Robert M.; Spaulding, Procter L.; Hall, Herbert E.

1969-01-01

Morphological, cultural, biochemical, and serological characteristics of 79 strains of Vibrio parahemolyticus isolated from patients suffering from gastroenteric disease in Japan were compared with 17 suspected V. parahemolyticus cultures isolated from wound infections and 14 nonpathogenic vibrios isolated from an estuarine environment in the United States. These groups were differentiated on the basis of several key reactions which included: the range of growth temperature and salt tolerance; the production of catalase and acetoin; the hydrolysis of starch; the fermentation and utilization as single carbon source of sucrose, cellobiose, and arabinose; and the ability to swarm on 1% agar. The separation of the groups on the basis of cultural and biochemical analyses was confirmed by means of slide agglutinations with specific anti-K antisera. The results of this study strongly suggest that the wound infection isolates are V. parahemolyticus species which are easily distinguished from the nonpathogenic estuarine vibrios. PMID:5784207

Morphological, cultural, biochemical, and serological comparison of Japanese strains of Vibrio parahemolyticus with related cultures isolated in the United States.

Science.gov (United States)

Twedt, R M; Spaulding, P L; Hall, H E

1969-05-01

Morphological, cultural, biochemical, and serological characteristics of 79 strains of Vibrio parahemolyticus isolated from patients suffering from gastroenteric disease in Japan were compared with 17 suspected V. parahemolyticus cultures isolated from wound infections and 14 nonpathogenic vibrios isolated from an estuarine environment in the United States. These groups were differentiated on the basis of several key reactions which included: the range of growth temperature and salt tolerance; the production of catalase and acetoin; the hydrolysis of starch; the fermentation and utilization as single carbon source of sucrose, cellobiose, and arabinose; and the ability to swarm on 1% agar. The separation of the groups on the basis of cultural and biochemical analyses was confirmed by means of slide agglutinations with specific anti-K antisera. The results of this study strongly suggest that the wound infection isolates are V. parahemolyticus species which are easily distinguished from the nonpathogenic estuarine vibrios.

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

Endo-xylanase (from Bacillus subtilis) or ferulic acid esterase (from Aspergillus niger) were expressed in wheat under the control of the endosperm-specific 1DX5 glutenin promoter. Constructs both with and without the endoplasmic reticulum retention signal (Lys-Asp-Glu-Leu) KDEL were used....... 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...

Pectin-modifying enzymes and pectin-derived materials: applications and impacts.

Science.gov (United States)

Bonnin, Estelle; Garnier, Catherine; Ralet, Marie-Christine

2014-01-01

Pectins are complex branched polysaccharides present in primary cell walls. As a distinctive feature, they contain high amount of partly methyl-esterified galacturonic acid and low amount of rhamnose and carry arabinose and galactose as major neutral sugars. Due to their structural complexity, they are modifiable by many different enzymes, including hydrolases, lyases, and esterases. Their peculiar structure is the origin of their physicochemical properties. Among others, their remarkable gelling properties make them a key additive for food industries. Pectin-degrading enzymes and -modifying enzymes may be used in a wide variety of applications to modulate pectin properties or produce pectin derivatives and oligosaccharides with functional as well as nutritional interests. This paper reviews the scientific information available on pectin structure, pectin-modifying enzymes, and the use of enzymes to produce pectin with controlled structure or pectin-derived oligosaccharides, with functional or nutritional interesting properties.

Yield and quality of pectins extractable from the peels of thai mango cultivars depending on fruit ripeness.

Science.gov (United States)

Sirisakulwat, Suparat; Nagel, Andreas; Sruamsiri, Pittaya; Carle, Reinhold; Neidhart, Sybille

2008-11-26

Pectins, recovered from the peels of four mango ( Mangifera indica L.) cultivars by mimicking industrial techniques, were evaluated in terms of yield, composition, macromolecular properties, and technofunctional quality. Freeze-dried peels of mature-green fruits, after major mesocarp softening, and at full ripeness were extracted using hot acid. The pectins were precipitated in propan-2-ol and their crude yields quantified as alcohol-insoluble substance. Like apple pomace, the dried peels provided hardly acetylated (DAc implied by arabinose/galactose ratios of 8-15 and 33-56 mol/100 mol, respectively. Limited galacturonic acid contents made the mango peel pectins less valuable than commercial apple pectins with regard to gelling capacity and thickening properties. Whereas starch and matrix glycan fragments almost completely degraded during ripening, depolymerization of pectins and galactans was insignificant. Technofunctional properties, modulated by extraction at different pH values, were ascribed to structural differences influencing macromolecular entanglements.

Germination, carbohydrate composition and vigor of cryopreserved Caesalpinia echinata seeds

Directory of Open Access Journals (Sweden)

Rafael Fonsêca Zanotti

2012-10-01

Full Text Available The present study investigated the germination and vigor of Caesalpinia echinata (Brazilwood seeds stored at negative temperatures. Recently harvested seeds were cryopreserved at -18º or -196ºC and periodically evaluated for germination, seed vigor and carbohydrate composition. The temperatures did not influence the germination percentages or vigor. The germination percentage decreased from 88% in recently harvested seeds to 60% after 730 days of storage. The different temperature and storage times tested did not affect the vigor seed germination as indicated by the measures of plant growth and survival. The different temperatures used did not cause changes in the carbohydrate composition. The tegument cell walls were rich in lignin, arabinose and xylose. The cytoplasm of the cotyledons and embryos had high levels of glucose, fructose, and sucrose. The cryopreservation technique here presented was effective in the conservation of Brazilwood seeds for the medium term.

Structural analysis of an innate immunostimulant from broccoli, Brassica oleracea var. italica.

Science.gov (United States)

Urai, Makoto; Kataoka, Keiko; Nishida, Satoshi; Sekimizu, Kazuhisa

2017-11-22

Vegetables are eaten as part of a healthy diet throughout the world, and some are also applied topically as a traditional medicine. We evaluated the innate immunostimulating activities of hot water extracts of various vegetables using the silkworm muscle contraction assay system, and found that broccoli, Brassica oleracea var. italica, contains a strong innate immunostimulant. We purified the innate immunostimulant from broccoli, and characterized the chemical structure by chemical analyses and NMR spectroscopy. The innate immunostimulant comprised galacturonic acid, galactose, glucose, arabinose, and rhamnose, and had a pectic-like polysaccharide structure. To determine the structural motif involved in the innate immunostimulating activity, we modified the structure by chemical and enzymatic treatment, and found that the activity was attenuated by pectinase digestion. These findings suggest that a pectic-like polysaccharide purified from broccoli has innate immune-stimulating activity, for which the polygalacturonic acid structure is necessary.

Purification and characterization of the glycoprotein allergen from Prosopis juliflora pollen.

Science.gov (United States)

Thakur, I S

1991-02-01

Highly active glycoprotein allergens have been isolated from pollen of Prosopis juliflora by a combination of Sephadex G-100 gel filtration and Sodium dodecyl sulphate-Poly-acrylamide gel electrophoresis. The glycoprotein fraction was homogeneous, and had molecular weight 20,000. The purified glycoprotein allergen contained 20% carbohydrate, mainly arabinose and galactose. Enzymatic digestion of glycoprotein with protease released glycopeptides of molecular weight ranging from less than 1,000 to more than 5,000 on Sephadex G-25 gel filtration. Antigenicity or allergenicity testing of these glycopeptides by immunodiffusion, immunoelectrophoresis, and radioallergosorbent test indicated complete loss of allergenic activity after digestion with protease whereas incubation with beta-D-galactosidase and periodate oxidation had little affect on the allergenic activity of the glycoprotein fraction. But incubation with alpha-D-glucosidase did not affect the allergenic activity significantly. All these tests indicated that protein played significant role in allergenicity of P. juliflora pollen.

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.

A strict anaerobic extreme thermophilic hydrogen-producing culture enriched from digested household waste

DEFF Research Database (Denmark)

Karakashev, Dimitar Borisov; Kotay, Shireen Meher; Trably, Eric

2009-01-01

The aim of this study was to enrich, characterize and identify strict anaerobic extreme thermophilic hydrogen (H-2) producers from digested household solid wastes. A strict anaerobic extreme thermophilic H-2 producing bacterial culture was enriched from a lab-scale digester treating household...... wastes at 70 degrees C. The enriched mixed culture consisted of two rod-shaped bacterial members growing at an optimal temperature of 80 degrees C and an optimal pH 8.1. The culture was able to utilize glucose, galactose, mannose, xylose, arabinose, maltose, sucrose, pyruvate and glycerol as carbon...... sources. Growth on glucose produced acetate, H-2 and carbon dioxide. Maximal H-2 production rate on glucose was 1.1 mmol l(-1) h(-1) with a maximum H-2 yield of 1.9 mole H-2 per mole glucose. 16S ribosomal DNA clone library analyses showed that the culture members were phylogenetically affiliated...

Physicochemical properties and antioxidant activities of polysaccharides from Gynura procumbens leaves by fractional precipitation.

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Li, Jing-En; Wang, Wen-Jun; Zheng, Guo-Dong; Li, Lin-Yan

2017-02-01

Four new polysaccharides (GPP-20, GPP-40, GPP-60 and GPP-80) were fractionated from Gynura procumbens leaves by 20%, 40%, 60% and 80% (v/v) ethanol, successively. Their physicochemical properties including the contents of neutral sugar, uronic acid and protein, as well as the monosaccharide composition were determined. In addition, the antioxidant activities of them were investigated via the reducing power assay and scavenging capacities of 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radicals and hydroxyl free radicals, respectively. The results indicated that apart from neutral sugar, they all contained uronic acids and proteins in their structures, which were further proved by the UV-vis and FT-IR spectra. Monosaccharide composition analysis implied that they all belonged to heteropolysaccharides consisted of arabinose, galactose, glucose, xylose and galacturonic acid with different types and ratios. What's more, GPP-20, GPP-40 and GPP-80 always exhibited better antioxidant activities than GPP-60 among these three antioxidant assays in vitro. Copyright © 2016 Elsevier B.V. All rights reserved.

Chemical studies on the polysaccharides of Salicornia brachiata.

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Sanandiya, Naresh D; Siddhanta, A K

2014-11-04

A group of 12 polysaccharide extracts were prepared from the tips, stem and roots of an Indian halophyte Salicornia brachiata Roxb. obtained by sequential extractions with cold water (CW), hot water (HW), aqueous ammonium oxalate (OX) and aqueous sodium hydroxide (ALK) solutions. Monosaccharide composition analysis revealed that all the polysaccharide extract samples consisted primarily of rhamnose, arabinose, mannose, galactose, glucose, whereas ribose and xylose were present only in some of the extracts. All the extracts exhibited low apparent viscosity (1.47-2.02 cP) and sulphate and contained no prominent toxic metal ions. Fucose was detected only in OX extract of the roots. These polysaccharides were found to be heterogeneous and highly branched (glycoside linkage analysis, size-exclusion chromatography, (13)C-NMR, FT-IR, circular dichroism and optical rotation data). Physico-chemical analyses of these polysaccharides including uronic acid, sulphate and protein contents were also carried out. This constitutes the first report on the profiling of Salicornia polysaccharides. Copyright © 2014 Elsevier Ltd. All rights reserved.

Subcritical Water Extraction of Monosaccharides from Oil Palm Fronds Hemicelluloses

International Nuclear Information System (INIS)

Norsyabilah, R.; Hanim, S.S.; Norsuhaila, M.H.; Noraishah, A.K.; Siti Kartina

2013-01-01

Oil palm plantations in Malaysia generate more than 36 million tones of pruned and felled oil palm fronds (OPF) and are generally considered as waste. The composition of monosaccharide in oil palm frond can be extracted using hydrothermal treatment for useful applications. The objectives of this study were to quantify the yield of monosaccharides at various reaction conditions; temperature 170 to 200 degree Celsius, pressure from 500 psi to 800 psi, reaction time from 5 to 15 min using subcritical water extraction and to determine the composition of oil palm frond hemicelluloses at optimum condition. The monosaccharides composition of oil palm frond hemicelluloses were analysed using High Performance Liquid Chromatography (HPLC). The highest yield of monosaccharides can be extracted from OPF at temperature of 190 degree Celsius, pressure of 600 psi and 10 min of contact time which is xylose the most abundant composition (11.79 %) followed with arabinose (2.82 %), glucose (0.61 %) and mannose (0.66 %). (author)

The biosynthesis of polysaccharides. Incorporation of d-[1-14C]glucose and d-[6-14C]glucose into plum-leaf polysaccharides

Science.gov (United States)

Andrews, P.; Hough, L.; Picken, J. M.

1965-01-01

1. The utilization of specifically labelled d-glucose in the biosynthesis of plum-leaf polysaccharides has been studied. After these precursors had been metabolized in plum leaves, the polysaccharides were isolated from the leaves, and their monosaccharide constituents isolated and purified. 2. Both the specific activities and the distribution of 14C along the carbon chains of the monosaccharides were determined. Significant 14C activity was found in units of d-galactose, d-glucose, d-xylose and l-arabinose, but their specific activities varied widely. The labelling patterns suggest that in the leaves the other monosaccharides all arise directly from d-glucose without any skeletal change in the carbon chain, other than the loss of a terminal carbon atom in the synthesis of pentoses. 3. The results indicated that within the leaf there are various precursor pools for polysaccharide synthesis and that these pools are not in equilibrium with one another. PMID:14342252

Investigation of Solid Energy Potential of Wood and Bark Obtained from Four Clones of a 2-Year Old Goat Willow

International Nuclear Information System (INIS)

Han, Sim-Hee; Shin, Soo-Jeong

2014-01-01

To investigate the solid raw material characteristics of willow (Salix caprea) bark and woody core, this study analyzed overall chemical composition, monosaccharide composition, ash content, and main ash composition of both tree components. Significant differences were observed between the two in terms of chemical composition, carbohydrate composition, ash content, and major inorganics. The ash content in bark was 3.8–4.7%, compared with 0.6–1.1% in the woody core. Polysaccharide content in the woody core was 62.8–70.6% but was as low as 44.1–47.6% in the bark. The main hemicelluloses consisting of monosaccharides were xylose in the case of the woody core, and xylose, galactose, and arabinose in the case of bark. Woody core biomass of willow provides superior solid fuel raw material, as compared with bark biomass, with higher heating values, less ash content, and less slagging-causing material.

Optimization for ultrasonic-microwave synergistic extraction of polysaccharides from Cornus officinalis and characterization of polysaccharides.

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Yin, Xiulian; You, Qinghong; Jiang, Zhonghai; Zhou, Xinghai

2016-02-01

Ultrasonic-microwave synergistic extraction (UMSE) of polysaccharides from Cornus officinalis was optimized by response surface methodology (RSM). The effect of four different factors on the yield of C. officinalis polysaccharides (COP) was studied. RSM results showed that the optimal conditions were extraction time of 31.49823 min, microwave power of 99.39769 W, and water-to-raw material ratio of 28.16273. The COP yield was 11.38±0.31% using the modified optimal conditions, which was consistent with the value predicted by the model. The crude COP was purified by DEAE-Cellulose 52 chromatography and Sephadex G-100 chromatography. Five fractions, namely, crude COP, COP-1, COP-2, COP-3, and COP-4, were obtained. Monosaccharide composition analysis revealed that the COP was composed of glucose, arabinose, fucose, xylose, mannose, and rhamnose. Preliminary structural characterizations of COP were conducted by scanning electron microscopy and Fourier transform infrared spectroscopy. Copyright © 2015 Elsevier B.V. All rights reserved.

Optimization of polysaccharides extraction from watermelon rinds: Structure, functional and biological activities.

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Romdhane, Molka Ben; Haddar, Anissa; Ghazala, Imen; Jeddou, Khawla Ben; Helbert, Claire Boisset; Ellouz-Chaabouni, Semia

2017-02-01

In the present work, optimization of hot water extraction, structural characteristics, functional properties, and biological activities of polysaccharides extracted from watermelon rinds (WMRP) were investigated. The physicochemical characteristics and the monosaccharide composition of these polysaccharides were then determined using chemical composition analysis, Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM) and gas chromatography-flame ionization detection (GC-FID). SEM images showed that extracted polysaccharides had a rough surface with many cavities. GC-FID results proved that galactose was the dominant sugar in the extracted polysaccharides, followed by arabinose, glucose, galacturonic acid, rhamnose, mannose, xylose and traces of glucuronic acid. The findings revealed that WMRP displayed excellent antihypertensive and antioxidant activities. Those polysaccharides had also a protection effect against hydroxyl radical-induced DNA damage. Functional properties of extracted polysaccharides were also evaluated. WMRP showed good interfacial dose-dependent proprieties. Overall, the results suggested that WMRP presents a promising natural source of antioxidants and antihypertensive agents. Copyright © 2016 Elsevier Ltd. All rights reserved.

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. Copyright © 2014. Published by Elsevier Ltd.

Improved growth of Lactobacillus bulgaricus and Streptococcus thermophilus as well as Increased antioxidant activity by biotransforming litchi pericarp polysaccharide with Aspergillus awamori.

Science.gov (United States)

Lin, Sen; Wen, Lingrong; Yang, Bao; Jiang, Guoxiang; Shi, John; Chen, Feng; Jiang, Yueming

2013-01-01

This study was conducted to increase the bioactivity of litchi pericarp polysaccharides (LPPs) biotransformed by Aspergillus awamori. Compared to the non-A. awamori-fermented LPP, the growth effects of A. awamori-fermented LPP on Lactobacillus bulgaricus and Streptococcus thermophilus were four and two times higher after 3 days of fermentation, respectively. Increased 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity and DNA protection activity of litchi pericarp polysaccharides were also achieved after A. awamori fermentation. Moreover, the relative content of glucose and arabinose in LPP after fermentation decreased from 58.82% to 22.60% and from 18.82% to 10.09%, respectively, with a concomitant increase in the relative contents of galactose, rhamnose, xylose, and mannose. Furthermore, lower molecular weight polysaccharides were obtained after A. awamori fermentation. It can be concluded that A. awamori was effective in biotransforming LPP into a bioactive mixture with lower molecular weight polysaccharides and higher antioxidant activity and relative galactose content.

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...

In vivo adenylate cyclase activity in ultraviolet- and gamma-irradiated Escherichia coli

Energy Technology Data Exchange (ETDEWEB)

Chatterjee, A; Bhattacharya, A K

1988-06-01

The incorporation of (/sup 14/C)adenine into the cyclic AMP fraction by whole cells of Escherichia coli B/r was taken as a measure of the in vivo adenylate cyclase activity. This activity was significantly inhibited by irradiation of the cells either with /sup 60/Co ..gamma..-rays or with UV light from a germicidal lamp, suggesting inhibition of cyclic AMP synthesis. The incubation of cells after irradiation with lower doses (50-100 Gy) of ..gamma..-rays produced a significant increase of in vivo adenylate cyclase activity, whereas there was no significant change after high doses (150 Gy and above). Dark incubation of cells after irradiation with UV light (54 J m/sup -2/) led to recovery of enzyme activity to the level measured in unirradiated cells. Thus it appears that the catabolite repression of L-arabinose isomerase induced by UV light, as well as ..gamma..-irradiation, is due to reduced cyclic AMP synthesis in irradiated cells.

In vivo adenylate cyclase activity in ultraviolet- and gamma-irradiated Escherichia coli

International Nuclear Information System (INIS)

Chatterjee, A.; Bhattacharya, A.K.

1988-01-01

The incorporation of [ 14 C]adenine into the cyclic AMP fraction by whole cells of Escherichia coli B/r was taken as a measure of the in vivo adenylate cyclase activity. This activity was significantly inhibited by irradiation of the cells either with 60 Co γ-rays or with UV light from a germicidal lamp, suggesting inhibition of cyclic AMP synthesis. The incubation of cells after irradiation with lower doses (50-100 Gy) of γ-rays produced a significant increase of in vivo adenylate cyclase activity, whereas there was no significant change after high doses (150 Gy and above). Dark incubation of cells after irradiation with UV light (54 J m -2 ) led to recovery of enzyme activity to the level measured in unirradiated cells. Thus it appears that the catabolite repression of L-arabinose isomerase induced by UV light, as well as γ-irradiation, is due to reduced cyclic AMP synthesis in irradiated cells. (author)

In vivo adenylate cyclase activity in ultraviolet- and gamma-irradiated Escherichia coli.

Science.gov (United States)

Chatterjee, A; Bhattacharya, A K

1988-06-01

The incorporation of [14C]adenine into the cyclic AMP fraction by whole cells of Escherichia coli B/r was taken as a measure of the in vivo adenylate cyclase activity. This activity was significantly inhibited by irradiation of the cells either with 60Co gamma-rays or with UV light from a germicidal lamp, suggesting inhibition of cyclic AMP synthesis. The incubation of cells after irradiation with lower doses (50-100 Gy) of gamma-rays produced a significant increase of in vivo adenylate cyclase activity, whereas there was no significant change after higher doses (150 Gy and above). Dark incubation of cells after irradiation with UV light (54 J m-2) led to recovery of enzyme activity to the level measured in unirradiated cells. Thus it appears that the catabolite repression of L-arabinose isomerase induced by UV light, as well as gamma-irradiation, is due to reduced cyclic AMP synthesis in irradiated cells.

Physicochemical properties and membrane biofouling of extra-cellular polysaccharide produced by a Micrococcus luteus strain.

Science.gov (United States)

Feng, Lei; Li, Xiufen; Song, Ping; Du, Guocheng; Chen, Jian

2014-07-01

The physicochemical properties of the extra-cellular polysaccharide (EPS) produced by a Micrococcus luteus strain, a dominating strain isolated from membrane biofouling layer, were determined in this study. The EPS isolated from this strain was measured to have an average molecular weight of 63,540 Da and some typical polysaccharide absorption peaks in Fourier transform infrared spectrum. Monosaccharide components of the EPS contained rhamnose, fucose, arabinose, xylose, mannose, galactose and glucose in a molar ratio of 0.2074:0.0454:0.0262:0.0446:1.7942:1.2086:0.4578. Pseudo plastic properties were also observed for the EPS through the rheological measurement. The EPS was further characterized for its behavior to cause membrane flux decline. The results showed that both flux declines for polyvinylidenefluoride (PVDF) and polypropylene membranes became more severe as EPS feed concentration increased. A higher irreversible fouling for the PVDF membrane suggested that the EPS had the larger fouling potential to this microfiltration membrane.

Production, structural characterization and gel forming property of a new exopolysaccharide produced by Agrobacterium HX1126 using glycerol or d-mannitol as substrate.

Science.gov (United States)

Liu, Yongmei; Gu, Qiuya; Ofosu, Fred Kwame; Yu, Xiaobin

2016-01-20

A strain Agrobacterium HX1126 was isolated from soil sample near the canal in Wuxi. Glycerol was used as carbon source for the production of a new exopolysaccharide which was named PGHX. PGHX composed mainly of galactose, with lower amounts of arabinose and aminogalactose. It was found that this strain could use d-mannitol as carbon source to produce PGHX too. A method for the preparation of crude PGHX was proposed and the crude PGHX can be formed in a gel formation when 30 g/L was put into the boiling water for 10 min, with an achieved gel strength of 957 g/cm(2). The concentration of proteins in the crude product was considered to be an important parameter which directly influence the gel forming property. The highest production of PGHX (24.9 g/L) was obtained under the nitrogen depletion condition. The structure of the product was confirmed by NMR and FTIR. Copyright © 2015 Elsevier Ltd. All rights reserved.

Complete oxidative conversion of lignocellulose derived non-glucose sugars to sugar acids by Gluconobacter oxydans.

Science.gov (United States)

Yao, Ruimiao; Hou, Weiliang; Bao, Jie

2017-11-01

Non-glucose sugars derived from lignocellulose cover approximately 40% of the total carbohydrates of lignocellulose biomass. The conversion of the non-glucose sugars to the target products is an important task of lignocellulose biorefining research. Here we report a fast and complete conversion of the total non-glucose sugars from corn stover into the corresponding sugar acids by whole cell catalysis and aerobic fermentation of Gluconobacter oxydans. The conversions include xylose to xylonate, arabinose to arabonate, mannose to mannonate, and galactose to galactonate, as well as with glucose into gluconate. These cellulosic non-glucose sugar acids showed the excellent cement retard setting property. The mixed cellulosic sugar acids could be used as cement retard additives without separation. The conversion of the non-glucose sugars not only makes full use of lignocellulose derived sugars, but also effectively reduces the wastewater treatment burden by removal of residual sugars. Copyright © 2017 Elsevier Ltd. All rights reserved.

Carbohydrate composition of peach palm (Bactris gasipaes Kunth) by-products flours.

Science.gov (United States)

Bolanho, Beatriz Cervejeira; Danesi, Eliane Dalva Godoy; Beléia, Adelaide Del Pino

2015-06-25

The flours obtained from peach palm by-products are rich in dietary fiber (62-71%) and they can be used as food ingredients. The aim of this work was to investigate the carbohydrate composition of the flours processed from the residual parts (stem and median sheath) of a hearts-of-palm industry. The flours were fractionated, based on their solubility, whose monomeric compounds were determined. The fraction containing mostly cellulose (S5) was the most abundant (26-28%), followed by the sum of fractions (S2, 53, S4) extracted with alkaline solutions (21-22%). The S1 fraction contained the highest percentage of uronic acids, which characterizes the presence of pectin. Xylose and arabinose were found in high proportion in S2 and S3 fractions. The S4 and S5 fractions, rich in glucose, were the main portion of the cell wall material and correspond to the insoluble fraction of the dietary fiber. Copyright © 2015 Elsevier Ltd. All rights reserved.

Modification by preirradiation growth conditions of the shoulder of the UV fluence-survival curve of Escherichia coli B/r WP2 thy trp and changes in mutagenic response toward tryptophan prototrophy

International Nuclear Information System (INIS)

Doudney, C.O.

1978-01-01

The distinct three-section UV fluence-mutation frequency response (MFR) curve demonstrated in Escherichia coli strain B/r WP2 thy trp and its uvrA derivative supports the SOS hypothesis and suggests that trp + revertants can arise either from isolated lesions (1DM) plus SOS induction or from two lesions in proximity (2DM). Preirradiation growth on arabinose instead of glucose converted the fluence-survival curve from highly shouldered to exponential but did not affect the three-section MFR curve. Prestarvation of the uvrA + strain for typtophan, which drastically increases the expanse of the shoulder of the survival curve, greatly decreased both 1DM and 2DM. With the uvrA strain the increase in shoulder expanse after typtophan prestarvation was accompanied by greatly increased 2DM but no change in 1DM. Preincubation with chloramphenicol induced an even greater increase in 2DM response than amino acid prestarvation. Nalidixic acid, which prevents DNA accumulation, eliminated the response. (Auth.)

Actinonin, a naturally occurring antibacterial agent, is a potent deformylase inhibitor.

Science.gov (United States)

Chen, D Z; Patel, D V; Hackbarth, C J; Wang, W; Dreyer, G; Young, D C; Margolis, P S; Wu, C; Ni, Z J; Trias, J; White, R J; Yuan, Z

2000-02-15

Peptide deformylase (PDF) is essential in prokaryotes and absent in mammalian cells, thus making it an attractive target for the discovery of novel antibiotics. We have identified actinonin, a naturally occurring antibacterial agent, as a potent PDF inhibitor. The dissociation constant for this compound was 0.3 x 10(-)(9) M against Ni-PDF from Escherichia coli; the PDF from Staphylococcus aureus gave a similar value. Microbiological evaluation revealed that actinonin is a bacteriostatic agent with activity against Gram-positive and fastidious Gram-negative microorganisms. The PDF gene, def, was placed under control of P(BAD) in E. coli tolC, permitting regulation of PDF expression levels in the cell by varying the external arabinose concentration. The susceptibility of this strain to actinonin increases with decreased levels of PDF expression, indicating that actinonin inhibits bacterial growth by targeting this enzyme. Actinonin provides an excellent starting point from which to derive a more potent PDF inhibitor that has a broader spectrum of antibacterial activity.

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. Copyright © 2015 Elsevier Ltd. All rights reserved.

Characterization and antioxidant activities of polysaccharides from thirteen boletus mushrooms.

Science.gov (United States)

Zhang, Lan; Hu, Yu; Duan, Xiaoyu; Tang, Tingting; Shen, Yingbin; Hu, Bin; Liu, Aiping; Chen, Hong; Li, Cheng; Liu, Yuntao

2018-07-01

Water-soluble polysaccharides were extracted from the caps and stipes of thirteen boletus mushrooms representing five different species collected in Southwest China. Investigations of their structures and antioxidant activities allowed an evaluation of structure-function relationships. The polysaccharides were composed mainly of the monosaccharides arabinose, xylose, mannose, glucose and galactose. Most samples displayed a broad molecular weight range, with significant differences observed between the molecular weight ranges of the polysaccharides from the caps and the stipes. FT-IR spectral analysis of the polysaccharides revealed that most of polysaccharides from boletus mushrooms (except Boletus edulis) contained a pyranose ring. The antioxidant activities of the polysaccharides in stipes showed a significant correlation with their monosaccharide composition, and were also related to their molecular weight and anomeric configuration. Suillellus luridus collected in Pingwu, Mianyang, Sichuan, China had remarkably superior antioxidant activity and might be developed as a natural antioxidant. Copyright © 2018 Elsevier B.V. All rights reserved.

Biomass saccharification is largely enhanced by altering wall polymer features and reducing silicon accumulation in rice cultivars harvested from nitrogen fertilizer supply.

Science.gov (United States)

Zahoor; Sun, Dan; Li, Ying; Wang, Jing; Tu, Yuanyuan; Wang, Yanting; Hu, Zhen; Zhou, Shiguang; Wang, Lingqiang; Xie, Guosheng; Huang, Jianliang; Alam, Aftab; Peng, Liangcai

2017-11-01

In this study, two rice cultivars were collected from experimental fields with seven nitrogen fertilizer treatments. All biomass samples contained significantly increased cellulose contents and reduced silica levels, with variable amounts of hemicellulose and lignin from different nitrogen treatments. Under chemical (NaOH, CaO, H 2 SO 4 ) and physical (hot water) pretreatments, biomass samples exhibited much enhanced hexoses yields from enzymatic hydrolysis, with high bioethanol production from yeast fermentation. Notably, both degree of polymerization (DP) of cellulose and xylose/arabinose (Xyl/Ara) ratio of hemicellulose were reduced in biomass residues, whereas other wall polymer features (cellulose crystallinity and monolignol proportion) were variable. Integrative analysis indicated that cellulose DP, hemicellulosic Xyl/Ara and silica are the major factors that significantly affect cellulose crystallinity and biomass saccharification. Hence, this study has demonstrated that nitrogen fertilizer supply could largely enhance biomass saccharification in rice cultivars, mainly by reducing cellulose DP, hemicellulosic Xyl/Ara and silica in cell walls. Copyright © 2017 Elsevier Ltd. All rights reserved.

High production of D-tagatose by the addition of boric acid.

Science.gov (United States)

Lim, Byung-Chul; Kim, Hye-Jung; Oh, Deok-Kun

2007-01-01

An L-arabinose isomerase mutant enzyme from Geobacillus thermodenitrificans was used to catalyze the isomerization of D-galactose to D-tagatose with boric acid. Maximum production of D-tagatose occurred at pH 8.5-9.0, 60 degrees C, and 0.4 molar ratio of boric acid to D-galactose, and the production increased with increasing enzyme concentration. Under the optimum conditions, the enzyme (10.8 units/mL) converted 300 g/L D-galactose to 230 g/L D-tagatose for 20 h with a yield of 77% (w/w); the production and conversion yield with boric acid were 1.5-fold and 24% higher than without boric acid, respectively. In 24 h, the enzyme produced 370 g/L D-tagatose from 500 g/L D-galactose with boric acid, corresponding to a conversion yield of 74% (w/w) and a production rate of 15.4 g/L.h. The production and yield of D-tagatose obtained in this study are unprecedented.

Discovering metabolic indices for early detection of squash (Cucurbita maxima) storage quality using GC-MS-based metabolite profiling.

Science.gov (United States)

Okazaki, K; Kimura, Y; Sugiyama, K; Kami, D; Nakamura, T; Oka, N

2016-04-01

Squash (Cucubita maxima) cultivars with good storage qualities are needed for breeding to improve poor crop supply during winter in Japan. We measured changes in squash constituents during different storage periods to identify compounds that were suitable to be used as indices of storage quality. Principal components analysis of compounds at 1-5 months after harvest showed that PC1 scores were lower for cultivars with a higher rather than lower SQ (storage quality) ranks. Partial least-squares regression analysis was performed using the peak areas of all compounds identified from the 15 cultivars at 1 month after harvest as explanation variables and SQ as the target variable. Variable influence on projection scores and rank correlation coefficients were higher for arabinose and xylose, which showed less temporal change during the storage period; hence, they were considered to be suitable indicators for storage evaluation. These data will be useful for future studies aiming to improve storage quality of squash. Copyright © 2015 Elsevier Ltd. All rights reserved.

Human Immunodeficiency Virus Type 1 Protease and the Emergence of Drug Resistance

DEFF Research Database (Denmark)

Poulsen, Nina Rødtness

in multi-drug-resistant PRs. Computational analysis of a vast number of inhibitor-resistant HIV-1 PR variants can broaden the knowledge of how and why the mutations arise, which would be a great advantage in the design on resistance-evading inhibitors. Here we present a diverse system to select...... in the virus life cycle has made it a major target for drug development and active site competitive inhibitors have been successful in the battle against HIV. Unfortunately, the massive drug pressure along with high-level replication and lack of proofreading by the viral reverse transcriptase have resulted...... for catalytically active HIV-1 PR in the presence of inhibitor. The system is based on the protein AraC, which regulates transcription of the araA, araB and araD genes necessary for arabinose catabolism in Escherichia coli, and its effectiveness was demonstrated by the isolation of both known and unknown inhibitor-resistant...

Efficient non-sterilized fermentation of biomass-derived xylose to lactic acid by a thermotolerant Bacillus coagulans NL01.

Science.gov (United States)

Ouyang, Jia; Cai, Cong; Chen, Hai; Jiang, Ting; Zheng, Zhaojuan

2012-12-01

Xylose is the major pentose and the second most abundant sugar in lignocellulosic feedstock. Its efficient utilization is regarded as a technical barrier to the commercial production of bulk chemicals from lignocellulosic biomass. This work aimed at evaluating the lactic acid production from the biomass-derived xylose using non-sterilized fermentation by Bacillus coagulans NL01. A maximum lactic acid concentration of about 75 g/L was achieved from xylose of 100 g/L after 72 h batch fermentation. Acetic acid and levulinic acid were identified as important inhibitors in xylose fermentation, which markedly reduced lactic acid productivity at 15 and 1.0 g/L, respectively. But low concentrations of formic acid (coagulans NL01, the same preference for glucose, xylose, and arabinose was observed and18.2 g/L lactic acid was obtained after 48 h fermentation. These results proved that B. coagulans NL01 was potentially well-suited for producing lactic acid from underutilized xylose-rich prehydrolysates.

Complete genome sequence of Paenibacillus riograndensis SBR5(T), a Gram-positive diazotrophic rhizobacterium.

Science.gov (United States)

Brito, Luciana Fernandes; Bach, Evelise; Kalinowski, Jörn; Rückert, Christian; Wibberg, Daniel; Passaglia, Luciane M; Wendisch, Volker F

2015-08-10

Paenibacillus riograndensis is a Gram-positive rhizobacterium which exhibits plant growth promoting activities. It was isolated from the rhizosphere of wheat grown in the state of Rio Grande do Sul, Brazil. Here we announce the complete genome sequence of P. riograndensis strain SBR5(T). The genome of P. riograndensis SBR5(T) consists of a circular chromosome of 7,893,056bps. The genome was finished and fully annotated, containing 6705 protein coding genes, 87 tRNAs and 27 rRNAs. The knowledge of the complete genome helped to explain why P. riograndensis SBR5(T) can grow with the carbon sources arabinose and mannitol, but not myo-inositol, and to explain physiological features such as biotin auxotrophy and antibiotic resistances. The genome sequence will be valuable for functional genomics and ecological studies as well as for application of P. riograndensis SBR5(T) as plant growth-promoting rhizobacterium. Copyright © 2015 Elsevier B.V. All rights reserved.

Investigation of Solid Energy Potential of Wood and Bark Obtained from Four Clones of a 2-Year Old Goat Willow

Energy Technology Data Exchange (ETDEWEB)

Han, Sim-Hee [Department of Forest Genetic Resources, Korea Forest Research Institute, Suwon (Korea, Republic of); Shin, Soo-Jeong, E-mail: soojshin@cbnu.ac.kr [Department of Wood and Paper Science, Chungbuk National University, Cheongju (Korea, Republic of)

2014-01-31

To investigate the solid raw material characteristics of willow (Salix caprea) bark and woody core, this study analyzed overall chemical composition, monosaccharide composition, ash content, and main ash composition of both tree components. Significant differences were observed between the two in terms of chemical composition, carbohydrate composition, ash content, and major inorganics. The ash content in bark was 3.8–4.7%, compared with 0.6–1.1% in the woody core. Polysaccharide content in the woody core was 62.8–70.6% but was as low as 44.1–47.6% in the bark. The main hemicelluloses consisting of monosaccharides were xylose in the case of the woody core, and xylose, galactose, and arabinose in the case of bark. Woody core biomass of willow provides superior solid fuel raw material, as compared with bark biomass, with higher heating values, less ash content, and less slagging-causing material.

Extracellular Enzyme Composition and Functional Characteristics of Aspergillus niger An-76 Induced by Food Processing Byproducts and Based on Integrated Functional Omics.

Science.gov (United States)

Liu, Lin; Gong, Weili; Sun, Xiaomeng; Chen, Guanjun; Wang, Lushan

2018-02-07

Byproducts of food processing can be utilized for the production of high-value-added enzyme cocktails. In this study, we utilized integrated functional omics technology to analyze composition and functional characteristics of extracellular enzymes produced by Aspergillus niger grown on food processing byproducts. The results showed that oligosaccharides constituted by arabinose, xylose, and glucose in wheat bran were able to efficiently induce the production of extracellular enzymes of A. niger. Compared with other substrates, wheat bran was more effective at inducing the secretion of β-glucosidases from GH1 and GH3 families, as well as >50% of proteases from A1-family aspartic proteases. Compared with proteins induced by single wheat bran or soybean dregs, the protein yield induced by their mixture was doubled, and the time required to reach peak enzyme activity was shortened by 25%. This study provided a technical platform for the complex formulation of various substrates and functional analysis of extracellular enzymes.

d-Tagatose production by permeabilized and immobilized Lactobacillus plantarum using whey permeate.

Science.gov (United States)

Jayamuthunagai, J; Srisowmeya, G; Chakravarthy, M; Gautam, P

2017-07-01

The aim of the work is to produce d-Tagatose by direct addition of alginate immobilized Lactobacillus plantarum cells to lactose hydrolysed whey permeate. The cells were untreated and immobilized (UIC), permeabilized and immobilized (PIC) and the relative activities were compared with purified l-arabinose isomerase (l-AI) for d-galactose isomerization. Successive lactose hydrolysis by β-galactosidase from Escherichia coli and d-galactose isomerization using l-AI from Lactobacillus plantarum was performed to investigate the in vivo production of d-tagatose in whey permeate. In whey permeate, maximum conversion of 38% and 33% (w/w) d-galactose isomerization by PIC and UIC has been obtained. 162mg/g and 141mg/g of d-tagatose production was recorded in a 48h reaction time at 50°C, pH 7.0 with 5mM Mn 2+ ion concentration in the initial substrate mixture. Copyright © 2017 Elsevier Ltd. All rights reserved.

Inhibitory effects of xylitol on gastric emptying and food intake

International Nuclear Information System (INIS)

Shafer, R.B.; Levine, A.S.; Marlette, J.M.; Morley, J.E.

1985-01-01

The authors have previously shown, using a 99m-Tc scrambled egg meal, that pentose sugars (i.e. xylose and arabinose) markedly prolong gastric emptying. Others have reported that slowing of gastric emptying may decrease appetite and thus decrease food intake. In the present study, the authors utilized the effects of xylitol (an FDA-approved pentose sugar) on gastric emptying to study the correlation between gastric emptying and food intake. Initially, gastric emptying was measured in human volunteers utilizing a standardized 99m-Tc-scrambled egg meal washed with 50 cc tap water. Results demonstrated a significant reduction in food intake (892 +- 65 kcal with water vs 654 +- 26 kcal following the ingestion of 25 gm xylitol (p<0.05). We conclude that the effect of pentose sugars in prolonging gastric emptying directly influences food intake and contributes to early satiety. The data suggest a role of xylitol as an essentially non-caloric food additive potentially important in diet control

Potential utilization of Citrullus lanatus var. Colocynthoides waste as a novel source of pectin.

Science.gov (United States)

Korish, Mohamed

2015-04-01

The Citrullus lanatus var. Colocynthoides is an ancestor type of watermelon. It was investigated as a new source of pectin. It was cultivated in Egypt for seeds only, while the remaining fruits are discarded as waste. Effect of different extraction conditions such as pH, solid: liquid ratio, temperature and extraction time on pectin yield of Citrullus lanatus var. Colocynthoides waste was investigated in the present study. The highest yield (19.75 % w/w) was achieved at pH 2, solid: liquid ratio1:15 and 85 °C, for 60 min. Methylation degree and galacturonic acid content of extracted pectin were 55.25 %, w/w and 76.84 %, w/w. The main neutral sugars were galactose followed by arabinose and rhamnose. In addition, glucose, xylose and mannose existed as constituents in the pectin hydrolysate. The results indicated that Citrullus lanatus var. Colocynthoide waste is a potential new source of pectin.

Inhibitory effects of xylitol on gastric emptying and food intake

Energy Technology Data Exchange (ETDEWEB)

Shafer, R.B.; Levine, A.S.; Marlette, J.M.; Morley, J.E.

1985-05-01

The authors have previously shown, using a 99m-Tc scrambled egg meal, that pentose sugars (i.e. xylose and arabinose) markedly prolong gastric emptying. Others have reported that slowing of gastric emptying may decrease appetite and thus decrease food intake. In the present study, the authors utilized the effects of xylitol (an FDA-approved pentose sugar) on gastric emptying to study the correlation between gastric emptying and food intake. Initially, gastric emptying was measured in human volunteers utilizing a standardized 99m-Tc-scrambled egg meal washed with 50 cc tap water. Results demonstrated a significant reduction in food intake (892 +- 65 kcal with water vs 654 +- 26 kcal following the ingestion of 25 gm xylitol (p<0.05). We conclude that the effect of pentose sugars in prolonging gastric emptying directly influences food intake and contributes to early satiety. The data suggest a role of xylitol as an essentially non-caloric food additive potentially important in diet control.

Improved Growth of Lactobacillus bulgaricus and Streptococcus thermophilus as well as Increased Antioxidant Activity by Biotransforming Litchi Pericarp Polysaccharide with Aspergillus awamori

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Sen Lin

2013-01-01

Full Text Available This study was conducted to increase the bioactivity of litchi pericarp polysaccharides (LPPs biotransformed by Aspergillus awamori. Compared to the non-A. awamori-fermented LPP, the growth effects of A. awamori-fermented LPP on Lactobacillus bulgaricus and Streptococcus thermophilus were four and two times higher after 3 days of fermentation, respectively. Increased 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity and DNA protection activity of litchi pericarp polysaccharides were also achieved after A. awamori fermentation. Moreover, the relative content of glucose and arabinose in LPP after fermentation decreased from 58.82% to 22.60% and from 18.82% to 10.09%, respectively, with a concomitant increase in the relative contents of galactose, rhamnose, xylose, and mannose. Furthermore, lower molecular weight polysaccharides were obtained after A. awamori fermentation. It can be concluded that A. awamori was effective in biotransforming LPP into a bioactive mixture with lower molecular weight polysaccharides and higher antioxidant activity and relative galactose content.

Sn-Beta zeolites with borate salts catalyse the epimerization of carbohydrates via an intramolecular carbon shift

Science.gov (United States)

Gunther, William R.; Wang, Yuran; Ji, Yuewei; Michaelis, Vladimir K.; Hunt, Sean T.; Griffin, Robert G.; Román-Leshkov, Yuriy

2012-01-01

Carbohydrate epimerization is an essential technology for the widespread production of rare sugars. In contrast to other enzymes, most epimerases are only active on sugars substituted with phosphate or nucleotide groups, thus drastically restricting their use. Here we show that Sn-Beta zeolite in the presence of sodium tetraborate catalyses the selective epimerization of aldoses in aqueous media. Specifically, a 5 wt% aldose (for example, glucose, xylose or arabinose) solution with a 4:1 aldose:sodium tetraborate molar ratio reacted with catalytic amounts of Sn-Beta yields near-equilibrium epimerization product distributions. The reaction proceeds by way of a 1,2 carbon shift wherein the bond between C-2 and C-3 is cleaved and a new bond between C-1 and C-3 is formed, with C-1 moving to the C-2 position with an inverted configuration. This work provides a general method of performing carbohydrate epimerizations that surmounts the main disadvantages of current enzymatic and inorganic processes. PMID:23047667

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.

Immunostimulatory Effects of Polysaccharides Isolated from Makgeolli (Traditional Korean Rice Wine

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Chang-Won Cho

2014-04-01

Full Text Available Makgeolli is a traditional Korean rice wine, reported to have various biological functions. In this study, the immunostimulatory activity of a polysaccharide from makgeolli (PSM was investigated. The polysaccharide fraction was isolated from makgeolli by hot water extraction, ethanol precipitation, dialysis, and lyophilization. The major constituents in PSM were neutral sugars (87.3%. PSM was composed of five different sugars, glucose, mannose, galactose, xylose, and arabinose. In normal mice, PSM treatment increased the spleen index (p < 0.05 as well as splenocyte proliferation (p < 0.05 in combination with concanavalin A or lipopolysaccharide. The immunostimulatory activities of PSM were also examined in cyclophosphamide (CY-induced immunosuppressed mice. Mice treated with PSM exhibited increased splenocyte proliferation (p < 0.05, natural killer cell activity, and white blood cell counts (p < 0.01 compared with immunosuppressed mice. These results indicate that PSM can enhance immune function in normal mice and CY-induced immunosuppressed mice.

Extraction, Preliminary Characterization and Evaluation of in Vitro Antitumor and Antioxidant Activities of Polysaccharides from Mentha piperita

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Xin Liu

2014-09-01

Full Text Available 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.

Radiation and enzyme degradation of cellulose materials

International Nuclear Information System (INIS)

Duchacek, V.

1983-01-01

The results are summed up of a study of the effect of gamma radiation on pure cellulose and on wheat straw. The irradiation of cellulose yields acid substances - formic acid and polyhydroxy acids, toxic malondialdehyde and the most substantial fraction - the saccharides xylose, arabinose, glucose and certain oligosaccharides. A ten-fold reduction of the level of cellulose polymerization can be caused by relatively small doses - (up to 250 kGy). A qualitative analysis was made of the straw before and after irradiation and it was shown that irradiation had no significant effect on the qualitative composition of the straw. A 48 hour enzyme hydrolysis of the cellulose and straw were made after irradiation and an economic evaluation of the process was made. Radiation pretreatment is technically and economically advantageous; the production of fodder using enzyme hydrolysis of irradiated straw is not economically feasible due to the high cost of the enzyme. (M.D.)

Studies on effective atomic numbers and electron densities in amino acids and sugars in the energy range 30-1333 keV

International Nuclear Information System (INIS)

Gowda, Shivalinge; Krishnaveni, S.; Gowda, Ramakrishna

2005-01-01

The effective atomic numbers and electron densities of the amino acids glycine, alanine, serine, valine, threonine, leucine, isoleucine, aspartic acid, lysine, glutamic acid, histidine, phenylalanine, arginine, tyrosine, tryptophane and the sugars arabinose, ribose, glucose, galactose, mannose, fructose, rhamnose, maltose, melibiose, melezitose and raffinose at the energies 30.8, 35.0, 81.0, 145, 276.4, 302.9, 356, 383.9, 661.6, 1173 and 1332.5 keV were calculated by using the measured total attenuation cross-sections. The interpolations of total attenuation cross-sections for photons of energy E in elements of atomic number Z was performed using the logarithmic regression analysis of the XCOM data in the photon energy region 30-1500 keV. The best-fit coefficients obtained by a piece wise interpolation method were used to find the effective atomic number and electron density of the compounds. These values are found to be in good agreement with the theoretical values calculated based on XCOM data

Studies on effective atomic numbers and electron densities in amino acids and sugars in the energy range 30-1333 keV

Energy Technology Data Exchange (ETDEWEB)

Gowda, Shivalinge [Department of Studies in Physics, University of Mysore, Manasagangotri, Mysore 570 006 (India); Krishnaveni, S. [Department of Studies in Physics, University of Mysore, Manasagangotri, Mysore 570 006 (India); Gowda, Ramakrishna [Department of Studies in Physics, University of Mysore, Manasagangotri, Mysore 570 006 (India)]. E-mail: ramakrishnagowda@yahoo.com

2005-10-15

The effective atomic numbers and electron densities of the amino acids glycine, alanine, serine, valine, threonine, leucine, isoleucine, aspartic acid, lysine, glutamic acid, histidine, phenylalanine, arginine, tyrosine, tryptophane and the sugars arabinose, ribose, glucose, galactose, mannose, fructose, rhamnose, maltose, melibiose, melezitose and raffinose at the energies 30.8, 35.0, 81.0, 145, 276.4, 302.9, 356, 383.9, 661.6, 1173 and 1332.5 keV were calculated by using the measured total attenuation cross-sections. The interpolations of total attenuation cross-sections for photons of energy E in elements of atomic number Z was performed using the logarithmic regression analysis of the XCOM data in the photon energy region 30-1500 keV. The best-fit coefficients obtained by a piece wise interpolation method were used to find the effective atomic number and electron density of the compounds. These values are found to be in good agreement with the theoretical values calculated based on XCOM data.

Effect of grape juice press fractioning on polysaccharide and oligosaccharide compositions of Pinot meunier and Chardonnay Champagne base wines.

Science.gov (United States)

Jégou, Sandrine; Hoang, Duc An; Salmon, Thomas; Williams, Pascale; Oluwa, Solomen; Vrigneau, Céline; Doco, Thierry; Marchal, Richard

2017-10-01

Press fractioning is an important step in the production of sparkling base wines to segregate the grape juices with different qualities. Grape juice fractions were collected during the pressing cycle at industrial and laboratory scales. The Pinot meunier and Chardonnay Champagne base wines obtained from the free-run juice and the squeezed juices exhibited strong differences from the beginning to the last step of pressing cycle for numerous enological parameters. Significant changes in polysaccharide (PS) and oligosaccharide (OS) base wine composition and concentration were found as the pressing cycle progressed. During the pressing cycle, the total PS concentration decreased by 31% (from 244 to 167mg/L) and 32% (from 201 to 136mg/L) in the Pinot meunier and Chardonnay wines respectively. The wine OS amounts varied between 97 and 139mg/L. The polysaccharide rich in arabinose and galactose (39-54%) and mannoproteins (38-55%) were the major PS in the base wines. Copyright © 2017 Elsevier Ltd. All rights reserved.

Dietary Fiber Extraction from Defatted Corn Hull by Hot-Compressed Water

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Wang Li

2018-06-01

Full Text Available Corn hulls were abundant and inexpensive byproducts of the corn dry or wet milling processes, but most of them were discarded as agro-wastes. The aim of this study was to extract the dietary fiber by hot-compressed water (HCW from defatted corn hull and to determine the chemical properties. Results showed that temperature and time played critical roles in extraction efficiency; the maximal yield of dietary fiber A (DFA extracted by HCW reached 33.0% at 150°C for 60 min. The yield of dietary fiber B (DFB increased from 2.0% to 56.9% as the temperature increased from 110 to 180°C, while the yield of solid residue (SR decreased from 88.7% to 27.7%. Fourier transform infrared spectroscopy (FT-IR results demonstrated that C-H, O-H, C=O, COO- occurred in the DFA, SR and DFB. The dietary fiber polysaccharides consisted of arabinose, galactose, glucose, xylose and uronic acid.

Studies on water soluble polysaccharides from Pithecellobium dulce (Roxb.) Benth. seeds.

Science.gov (United States)

Bagchi, S; Kumar, K Jayaram

2016-03-15

In this existing experimental work, water soluble PDP polysaccharides were secluded from Pithecellobium dulce (Roxb.) Benth. seeds. The physicochemical properties were analyzed in terms of swelling power, solubility, pH and water holding capacity. Micromeretic studies proved the polysaccharide may be used a potential pharmaceutical adjuvant. The polysaccharide was characterized by FT-IR, SEM, TGA and NMR techniques. Methylation analysis confirmed that the polysaccharide is composed of Arabinose (Araf) units. The chemical shifts of anomeric proton region were found in the region of 4.4-5.5ppm. Thermogravimetric analysis showed that PDP polysaccharide was thermally stable. The in vitro antioxidant capacities of the polysaccharide were investigated in terms of scavenging of hydroxyl radicals, 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radicals, hydrogen peroxide (H2O2) and reducing power assay. The polysaccharide fractions showed activity in a concentration dependent manner which was comparable to the standard, ascorbic acid. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

Gum in apricot (Prunus armeniaca L. shoots induced by methyl jasmonate

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Marian Saniewski

2013-12-01

Full Text Available It has been well known that some fungal pathogens (Monilia laxa, M. fructigena, Cytospora cincta, larvae of Grapholita molesta and plant hormone - ethylene, induce gummosis in apricot shoots. Methyl jasmonate (JA-Me was also found to induce gummosis in apricot shoots as well as biotic and abiotic factors mentioned above. In order to know the mode of action of JA-Me on gum induction and/or formation, chemical composition of polysaccharides (after hydrolysis in gums of apricot shoots induced by JA-Me compared with those by ethephon and their mixture, and naturally occurring ones was studied, resulted in the succesful identification of monosaccharides, and the similarity of a composition consisting of xylose, arabinose and galactose at molar ratio 1:10:14, respectively. These results suggest that beside different inducers of gum in apricot the mechanism of polysaccharides biosynthesis of gums is the same or similar. The physiological role for JA-Me on gum induction and/or formation in apricot shoots, and other species are also discussed.

Utilization of agricultural cellulose wastes

Energy Technology Data Exchange (ETDEWEB)

Valkanas, G N; Economidis, D G; Koukios, E G; Valkanas, C G

1977-05-05

Wastes, example, straw, are prehydrolyzed to convert pentosanes, starches, and hemicelluloses to monosaccharides; the remaining pulp is 50% cellulose. Thus, dry wheat straw 0.8 kg was treated with 10 L of 0.3% aqueous HCl at 5-5.5 atm and 145/sup 0/ and a space velocity of 0.55 L/min, washed with dry steam, followed by water at 120 to 130/sup 0/, and more dry steam, and compressed at 25 kg/cm/sup 2/ to yield a product containing 45 to 50 wt % water. The sugar solution obtained (1394 L) contained 1.34 wt % reducing sugars, a straw hydrolysis of 23 wt %, and comprised xylose 74.3, mannose 5.2, arabinose 11.8, glucose 5.9, galactose 2.9%, and furfural 0.16 g/L. The cellulose residue had a dry weight of 0.545 kg. a yield of 68.2 wt % and contained cellulose 53.1, hemicelluloses 12.6%, lignin 22.1, ash and extractables 12.2%. The degree of polymerization was 805 glucose units.

Qualitation and quantification of specific polysaccharides from Panax species using GC-MS, saccharide mapping and HPSEC-RID-MALLS.

Science.gov (United States)

Cheong, Kit-Leong; Wu, Ding-Tao; Deng, Yong; Leong, Fong; Zhao, Jing; Zhang, Wen-Jie; Li, Shao-Ping

2016-11-20

The objective of this study was to qualify and quantify the specific polysaccharides in Panax spp. The analyses of specific polysaccharides were performed by using GC-MS, saccharide mapping and high performance size exclusion chromatography (HPSEC) coupled with multi angle laser light scattering (MALLS) and refractive index detector (RID). Results showed that compositional monosaccharides were the same in different species of Panax and composed of rhamnose, arabinose, galacturonic acid, mannose, glucose, and galactose. Saccharide mapping results showed that glycosides linkages, which existed in specific polysaccharides from Panax spp., were similar. Additionally, the content of specific polysaccharides of P. ginseng, P. notoginseng and P. quinquefolium were 17.9-20.5mg/g, 11.9-15.0mg/g, and 9.9-13.3mg/g, respectively. P. ginseng, P. notoginseng, and P. quinquefolium could be clustered into three groups using both hierarchical cluster analysis and principal component analysis. The results possessed great potential in characterization and content determination of specific polysaccharides in Panax spp. Copyright © 2016 Elsevier Ltd. All rights reserved.

Influence of Carbohydrates on Secondary Metabolism in Fusarium avenaceum

Directory of Open Access Journals (Sweden)

Jens Laurids Sørensen

2013-09-01

Full Text Available Fusarium avenaceum is a widespread pathogen of important crops in the temperate climate zones that can produce many bioactive secondary metabolites, including moniliformin, fusarin C, antibiotic Y, 2-amino-14,16-dimethyloctadecan-3-ol (2-AOD-3-ol, chlamydosporol, aurofusarin and enniatins. Here, we examine the production of these secondary metabolites in response to cultivation on different carbon sources in order to gain insight into the regulation and production of secondary metabolites in F. avenaceum. Seven monosaccharides (arabinose, xylose, fructose, sorbose, galactose, mannose, glucose, five disaccharides (cellobiose, lactose, maltose, sucrose and trehalose and three polysaccharides (dextrin, inulin and xylan were used as substrates. Three F. avenaceum strains were used in the experiments. These were all able to grow and produce aurofusarin on the tested carbon sources. Moniliformin and enniatins were produced on all carbon types, except on lactose, which suggest a common conserved regulation mechanism. Differences in the strains was observed for production of fusarin C, 2-AOD-3-ol, chlamydosporol and antibiotic Y, which suggests that carbon source plays a role in the regulation of their biosynthesis.

Co-solvent pretreatment reduces costly enzyme requirements for high sugar and ethanol yields from lignocellulosic biomass.

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Nguyen, Thanh Yen; Cai, Charles M; Kumar, Rajeev; Wyman, Charles E

2015-05-22

We introduce a new pretreatment called co-solvent-enhanced lignocellulosic fractionation (CELF) to reduce enzyme costs dramatically for high sugar yields from hemicellulose and cellulose, which is essential for the low-cost conversion of biomass to fuels. CELF employs THF miscible with aqueous dilute acid to obtain up to 95 % theoretical yield of glucose, xylose, and arabinose from corn stover even if coupled with enzymatic hydrolysis at only 2 mgenzyme  gglucan (-1) . The unusually high saccharification with such low enzyme loadings can be attributed to a very high lignin removal, which is supported by compositional analysis, fractal kinetic modeling, and SEM imaging. Subsequently, nearly pure lignin product can be precipitated by the evaporation of volatile THF for recovery and recycling. Simultaneous saccharification and fermentation of CELF-pretreated solids with low enzyme loadings and Saccharomyces cerevisiae produced twice as much ethanol as that from dilute-acid-pretreated solids if both were optimized for corn stover. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

EFFECT OF XYLANASE ADDED TO A RYE-BASED DIET ON NUTRIENT UTILIZATION IN PIGS

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Jaroslav Heger

2012-02-01

Full Text Available The effect of enzyme xylanase derived from Trichoderma longibrachiatum supplemented to a rye-based diet on apparent ileal digestibility of amino acids and non-starch polysaccharides constituting sugars was studied. Enzymes supplementation at 200 mg.kg−1 increased (P˂0.05 the digestibility of total amino acids from 67.1 to 70.8. When the dietary concentration of enzyme increased from 0 to 100 mg.kg-1, the ileal digestibility of the NSP constituents gradually increased as well. No further increase was observed with the supplementation level of 200 mg.kg-1. The improvement in the digestibility of arabinose and xylose (685%, P˂0.05 was much higher in comparison with remaining sugars (110%, P˂0.05. The apparent ileal digestibility of galactose was positively influenced by xylanase but it remained negative in all dietary treatments, presumably due to the high concentration of galactose in endogenous secretions. It is concluded that xylanase effectively degrades non-starch polysaccharides in upper digestive tract and marginally improves amino acid availability in young pigs.

Polysaccharides from Arctium lappa L.: Chemical structure and biological activity.

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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. Copyright © 2016 Elsevier B.V. All rights reserved.

In situ enzyme aided adsorption of soluble xylan biopolymers onto cellulosic material.

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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. Copyright © 2016 Elsevier Ltd. All rights reserved.

Identification of polysaccharide hydrolases involved in autolytic degradation of Zea cell walls

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Nock, L.P.; Smith, C.J.

1987-01-01

Cell walls of Zea mays (cv L.G.11) seedlings labeled with 14 C were treated with α-amylase from Bacillus subtilis to remove starch and mixed linkage glucans. These walls released arabinose, xylose, galactose, and galacturonic acid in addition to glucose when they were allowed to autolyze. Methylation analysis was performed on samples of wall which had been incubated autolytically and the results indicated that degradation of the major polymer of the wall, the glucoarabinoxylan, had occurred. A number of glycanases could be dissociated from the wall by use of 3 M LiCL. The proteins which were released were found to contain a number of exoglycosidase activities in addition to being effective in degrading the polysaccharide substrates, araban, xylan, galactan, laminarin, mannan, and polygalacturonic acid. The effects of these enzymes on the wall during autolysis appear to result from endo-activity in addition to exo-activity. The structural changes that occurred in the cell walls during autolysis were found to be related to the changes previously found to occur in cell walls during auxin induced extension

Behavior of Triticum durum Desf. arabinoxylans and arabinogalactan peptides during industrial pasta processing.

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Ingelbrecht, J A; Verwimp, T; Grobet, P J; Delcour, J A

2001-04-01

Three industrial pasta processing lines for different products (macaroni, capellini and instant noodles) were sampled at three subsequent stages (semolina, extruded, and dried end products) in the process. Arabinoxylans (AX) and arabinogalactan peptides (AGP) were analyzed. Although very low endoxylanase activities were measured, the level of water-extractable AX (WE-AX) increased, probably because of mechanical forces. No change was observed in the level and structural characteristics of AGP. The WE-AX molecular weight (MW) profiles showed a very small shift toward lower MW profiles; those of AGP revealed no changes as a result of the production process. After separation of WE-AX and AGP, (1)H NMR analysis and gas chromatography of the alditol acetates obtained following hydrolysis, reduction, and acetylation revealed no changes in the arabinose substitution profile of the WE-AX samples during pasta processing. At optimal cooking times, WE-AX losses in the cooking water are small (maximally 5.9%). However, the loss of AGP is more pronounced (maximally 25.0%). Overcooking led to more losses of both components.

Sapodilla (Manilkara zapota Broth as an Alternative Media for Candida albicans

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Chen Chui Ying

2017-03-01

Full Text Available Objective: To determine whether sapodilla can be used to grow Candida albicans. Among all the high galactose and arabinose content fruits, the sapodilla was chosen because it is available year round and can get easily in market. Other than that, it also contains vitamins, calcium and phosphorus which are very useful for fungi growth. Methods: This study used an experimental study as a method of research. The researcher culture Candida albicans on the experimental sapodilla media and identifies the morphology of the fungi by using Gram staining method. The experiment will be replicated two times to get accurate result. The procedure of this experiment constitute of sapodilla media preparation, sapodilla media observation, organism preparation, planting and incubation, observation of fungal colonies and identification of the fungi. Results: In 0%, there was no fungal growth at all. In 5%, there was mild density of fungal colonies. In 10%, there was moderate density of fungal colonies and in 15% the fungal grew with very dense colonies. Conclusions: Sapodilla (Manilkara zapota broth can be used as an alternative media for Candida albicans.

Characterization of Grewia Gum, a Potential Pharmaceutical Excipient

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Elijah.I.Nep

2010-03-01

Full Text Available Grewia gum was extracted from the inner stem bark of Grewia mollis and characterized by several techniques such as gas chromatography (GC, gel permeation chromatography (GPC, scanning electron microscopy (SEM, differential scanning calorimetry (DSC and thermogravimetric analysis of the extracted sample. Spectroscopic techniques such as x-ray photoelectron spectroscopy (XPS, fourier-transformed infrared (FT-IR, solid-state nuclear magnetic resonance (NMR, and 1H and 13C NMR techniques were also used to characterize the gum. The results showed that grewia gum is a typically amorphous polysaccharide gum containing glucose, rhamnose, galactose, arabinose and xylose as neutral sugars. It has an average molecular weight of 5925 kDa expressed as the pullulan equivalent. The gum slowly hydrated in water, dispersing and swelling to form a highly viscous dispersion exhibiting pseudoplastic flow behaviour. The polysaccharide gum is thermally stable and may have application as stabilizer or suspending agent in foods, cosmetics and in pharmaceuticals. It may have application as a binder or sustained-release polymer matrix in tablets or granulations.

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

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

2016-10-20

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 methylesterification (62%) and acetylation (10%) and consists of different molecular weight populations in the range of 10-100kDa. Enzymatic fingerprinting was performed using a combination of pectin lyase (PL) and endo-polygalacturonase. Detailed information about the structure and level of galacturonic acid oligomers released was obtained using LC-HILIC-MS/ELSD and HPAEC. Predominantly, unsaturated and methyl-esterified oligomers (DP 3-5) were released indicating that high proportions of methylesterified 'PL degradable' areas were present within the pectin. The data revealed that homogalacturonan is the main building block of the extracted pectin and consists of long methylesterified/acetylated GalA sequences interspersed with small blocks of non-methyl-esterified GalA units. Copyright © 2016 Elsevier Ltd. All rights reserved.

Efficient production of D-tagatose using a food-grade surface display system.

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Liu, Yi; Li, Sha; Xu, Hong; Wu, Lingtian; Xu, Zheng; Liu, Jing; Feng, Xiaohai

2014-07-16

D-tagatose, a functional sweetener, is commonly transformed from D-galactose by L-arabinose isomerase (L-AI). In this study, a novel type of biocatalyst, L-AI from Lactobacillus fermentum CGMCC2921 displayed on the spore surface of Bacillus subtilis 168, was developed for producing D-tagatose. The anchored L-AI, exhibiting the relatively high bioactivity, suggested that the surface display system using CotX as the anchoring protein was successfully constructed. The stability of the anchored L-AI was significantly improved. Specifically, the consolidation of thermal stability representing 87% of relative activity was retained even at 80 °C for 30 min, which remarkably favored the production of D-tagatose. Under the optimal conditions, the robust spores can convert 75% D-galactose (100 g/L) into D-tagatose after 24 h, and the conversion rate remained at 56% at the third cycle. Therefore, this biocatalysis system, which could express the target enzyme on the food-grade vector, was an alternative method for the value-added production of D-tagatose.

Hydrothermal degradation of cellulosic matter to sugars and their fermentative conversion to protein

International Nuclear Information System (INIS)

Bobleter, O.; Niesner, R.; Roehr, M.

1976-01-01

For the hydrothermal degradation of cellulosic matter, an apparatus was developed in which water is used as extraction medium. Samples, 0.15 g each, of pure cellulose (filter paper), natural straw, and 14 C-labeled straw were treated at temperatures of between 200 and 275 0 C. Of the inserted cellulose, 65.7 percent was recovered at the optimum temperature as sugars and hydroxymethylfurfural. It was possible to degrade the straw selectively: at lower temperatures, the hemicellulose part of the plant matter was converted to xylose and arabinose; and then at higher temperatures, the cellulose was converted to glucose and cellobiose. At the same time, a certain amount of the sugars was transformed to furfural compounds. The growth behavior of the yeast Candida utilis (strain Weissenbach) was analyzed, using cellobiose, xylose, and glucose (standard) as carbon sources. The growth curves applying cellobiose were nearly identical to those of glucose. Xylose showed lower productivity than the hexoses. The main products of the hydrothermal degradation can, therefore, be used favorably as nutritive substances for this protein-producing yeast

Highly sulphated galactan from Halymenia durvillei (Halymeniales, Rhodophyta), a red seaweed of Madagascar marine coasts.

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Fenoradosoa, T A; Delattre, C; Laroche, C; Wadouachi, A; Dulong, V; Picton, L; Andriamadio, P; Michaud, P

2009-08-01

Halymenia durvillei is a red seaweed with a great potential as sulphated galactan producer collected in the coastal waters of small island of Madagascar (Nosy-be in Indian Ocean). To elucidate the structure of its polysaccharide, NMR (1H and 13C), FTIR, HPAEC and different colorimetric methods were carried out. It has been shown that this polysaccharide, consisted mainly of galactose, was branched by xylose and galactose in minor amounts. Arabinose and fucose were also detected. This galactan was found highly sulphated (42%, w/w) and pyruvylated (1.8%, w/w). Analysis of glycosidic linkages by CPG-MS and 13C NMR indicated that the polysaccharide has the defining linear backbone of alternating 3-beta-D-galactopyranosyl units and 4-linked alpha-L/D-galactopyranosyl residues. 3,6-Anhydrogalactose units have been also detected in minor quantity. This lambda-carrageenan like polysaccharide has shown original sulphatation patterns with 2-O (26%) or 2/6-O (58%) sulphated 3-linked beta-D-galactopyranosyl units and 6-O (19%) or 2/6-O (47%) 4-linked alpha-L/D-galactopyranosyl residues.

Design and synthesis of biotin analogues reversibly binding with streptavidin.

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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. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Frequency of enterococcus faecalis in saliva and root canals with treatment failure

International Nuclear Information System (INIS)

Khan, I.; Shan, T.; Manzoor, M.A.

2015-01-01

To compare the frequency of E. faecalis in the saliva and root canals of teeth associated with apical periodontitis due to endodontic treatment failure in the same patient. Study Design: Cross-sectional comparative study. Place and Duration of Study: Samples were collected from Operative Dentistry Department, AFID, while laboratory processing was done at AFIP, Rawalpindi. Study duration was one year. Patients and Methods: Fifty patients, both males and females with failed endodontic treatment were selected. Saliva and root canal samples were collected from each patient, inoculated on MacKonkey agar plate and incubated at 35-37 degree C for 48 hrs. E. faecalis colonies were identified by colony morphology, gramstain, catalase, bile asculin test, arabinose fermentation and growth in 6% NaCl nutrient broth. Results: The frequency of E. faecalis in saliva was 34% and in root canal it was 58%. Frequency between the presence of E. faecalis in root canals and saliva was found to be statistically different (p = 0.001). Conclusion: The presence of E. faecalis in root canal was not associated with their presence in saliva. (author)

Frequency of enterococcus faecalis in saliva and root canals with treatment failure

International Nuclear Information System (INIS)

Shan, T.; Manzoor, M.A.; Hussain, W.

2014-01-01

To compare the frequency of E.faecalis in the saliva and root canals of teeth associated with apical periodontitis due to endodontic treatment failure Study. Design: Cross-sectional comparative. Place and Duration of Study: Samples were collected from Operative Dentistry department, AFID, while laboratory processing was done at AFIP, Rawalpindi. Duration of this study was one year. Patients and Method: Fifty patients, both males and females with failed endodontic treatment were selected. Saliva and root canal samples were collected from each patient, inoculated on MacKonkey agar plate and incubated at 35-370 C for 48 hours. E.faecalis colonies were identified by colony morphology, Gram stain, catalase, bile asculin test, arabinose fermentation and growth in 6% NaCl nutrient broth. Results: The frequency of E.faecalis in saliva was 34% and 58% in root canal samples. Frequency of the presence of E.faecalis in root canals and saliva was found to be statistically different (p=0.000). Conclusion: The presence of E.faecalis in root canal was not associated with their presence in saliva. (author)

Antitumor and Immunomodulating Activities of Exopolysaccharide Produced by Big Cup Culinary- Medicinal Mushroom Clitocybe maxima (Higher Basidiomycetes) in Liquid Submerged Culture.

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Hu, Shu-Hui; Cheung, Peter Chi Keung; Hung, Raw-Pou; Chen, Yu-Kuei; Wang, Jinn-Chyi; Chang, Sue-Joan

2015-01-01

Water-soluble polysaccharides extracted from mushrooms have been found to have some physiological effects. In this study, exopolysaccharides (EPSs) were extracted by alcohol precipitation from cultivated broth of the mushroom Clitocybe maxima. EPSs with molecular weights of 10(4) and 10(5) Da were obtained by ultrafiltration; they are referred to as EPA and EPB, respectively. The major components of these EPSs were glucose, galactose, mannose, rhamnose, and arabinose. ICR mice with artificially induced metastatic pulmonary tumors were fed a daily diet containing EPA or EPB at doses of 8, 20, or 50 mg/kg. Results showed that the proliferation of pulmonary sarcoma lesions was lower in the groups fed EPS. In addition, the numbers of total T cells, CD4+ cells, CD8+ cells, and macrophages significantly increased in EPS-fed mice compared with the negative control group. The antitumor and immunomodulating effects observed in the EPB-fed groups were higher than those of EPA-fed groups. These results demonstrate the ability of EPSs of C. maxima to inhibit tumor cells while enhancing immune response.

Production of D-tagatose and bioethanol from onion waste by an intergrating bioprocess.

Science.gov (United States)

Kim, Ho Myeong; Song, Younho; Wi, Seung Gon; Bae, Hyeun-Jong

2017-10-20

The rapid increase of agricultural waste is becoming a burgeoning problem and considerable efforts are being made by numerous researchers to convert it into a high-value resource material. Onion waste is one of the biggest issues in a world of dwindling resource. In this study, the potential of onion juice residue (OJR) for producing valuable rare sugar or bioethanol was evaluated. Purified Paenibacillus polymyxaL-arabinose isomerase (PPAI) has a molecular weight of approximately 53kDa, and exhibits maximal activity at 30°C and pH 7.5 in the presence of 0.8mM Mn 2+ . PPAI can produce 0.99g D-tagatose from 10g OJR. In order to present another application for OJR, we produced 1.56g bioethanol from 10g OJR through a bioconversion and fermentation process. These results indicate that PPAI can be used for producing rare sugars in an industrial setting, and OJR can be converted to D-tagatose and bioethanol. Copyright © 2017 Elsevier B.V. All rights reserved.

Influence of carbohydrates on secondary metabolism in Fusarium avenaceum.

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Sørensen, Jens Laurids; Giese, Henriette

2013-09-24

Fusarium avenaceum is a widespread pathogen of important crops in the temperate climate zones that can produce many bioactive secondary metabolites, including moniliformin, fusarin C, antibiotic Y, 2-amino-14,16-dimethyloctadecan-3-ol (2-AOD-3-ol), chlamydosporol, aurofusarin and enniatins. Here, we examine the production of these secondary metabolites in response to cultivation on different carbon sources in order to gain insight into the regulation and production of secondary metabolites in F. avenaceum. Seven monosaccharides (arabinose, xylose, fructose, sorbose, galactose, mannose, glucose), five disaccharides (cellobiose, lactose, maltose, sucrose and trehalose) and three polysaccharides (dextrin, inulin and xylan) were used as substrates. Three F. avenaceum strains were used in the experiments. These were all able to grow and produce aurofusarin on the tested carbon sources. Moniliformin and enniatins were produced on all carbon types, except on lactose, which suggest a common conserved regulation mechanism. Differences in the strains was observed for production of fusarin C, 2-AOD-3-ol, chlamydosporol and antibiotic Y, which suggests that carbon source plays a role in the regulation of their biosynthesis.

Fermentation process optimization and chemical constituent analysis on longan (Dimocarpus longan Lour.) wine.

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Liu, Guoming; Sun, Jian; He, Xuemei; Tang, Yayuan; Li, Jiemin; Ling, Dongning; Li, Changbao; Li, Li; Zheng, Fengjin; Sheng, Jingfeng; Wei, Ping; Xin, Ming

2018-08-01

Based on single factor and orthogonal experiments, optimal fermentation conditions for longan wine were Saccharomyces cerevisiae strain of Lalvin K D , juice content of 70% and alcohol content of 10°. Sixteen amino acids were detected. Proline, alanine, glutamic acid and aspartic acid contents were relatively high. Sixty-three volatile aroma compounds were identified using solid-phase micro extraction and gas chromatography (SPME-GC). Ethyl lactate content was the highest, followed by octanoic acid ethyl ester, isoamyl alcohol and decanoic acid ethyl ester. Main functional components were polysaccharides. Longan wine polysaccharide (LWP) with molecular weight 10-30 kDa exhibited the highest hypoglycemic and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activities. 10-30 kDa polysaccharides mainly consisted of glucose, mannose, galactose, arabinose, galacturonic acid and glucuronic acid in molar ratio of 167.72:3.38:3.13:3.46:2.33:1. Infrared and nuclear magnetic resonance spectra confirmed that the sugar ring of 10-30 kDa polysaccharides was in the 〈beta〉-configuration. Copyright © 2018 Elsevier Ltd. All rights reserved.

Efficient method for the conversion of agricultural waste into sugar alcohols over supported bimetallic catalysts.

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Tathod, Anup P; Dhepe, Paresh L

2015-02-01

Promoter effect of Sn in the PtSn/γ-Al2O3 (AL) and PtSn/C bimetallic catalysts is studied for the conversion of variety of substrates such as, C5 sugars (xylose, arabinose), C6 sugars (glucose, fructose, galactose), hemicelluloses (xylan, arabinogalactan), inulin and agricultural wastes (bagasse, rice husk, wheat straw) into sugar alcohols (sorbitol, mannitol, xylitol, arabitol, galactitol). In all the reactions, PtSn/AL showed enhanced yields of sugar alcohols by 1.5-3 times than Pt/AL. Compared to C, AL supported bimetallic catalysts showed prominent enhancement in the yields of sugar alcohols. Bimetallic catalysts characterized by X-ray diffraction study revealed the stability of catalyst and absence of alloy formation thereby indicating that Pt and Sn are present as individual particles in PtSn/AL. The TEM analysis also confirmed stability of the catalysts and XPS study disclosed formation of electron deficient Sn species which helps in polarizing carbonyl bond to achieve enhanced hydrogenation activity. Copyright © 2014 Elsevier Ltd. All rights reserved.

Reactivities of some aldoses towards iodine in alkaline

International Nuclear Information System (INIS)

Azmat, R.; Nizami, S.S.

2005-01-01

The kinetics studies of oxidation of some reducing sugars by aqueous alkaline solution of iodine investigated. Results demonstrated that iodine in the presence of alkali converted into hypoiodous acid which was effective oxidizing species. Reaction between iodine and sugars was slowest reaction. The rate of oxidation of sugars was affected by change in pH of the medium and maximum at pH 11.4 where the concentration of hypoiodous acid was maximum which oxidized the sugars into respective acids. The rate of oxidation followed first order kinetics with respect to substrate and obeyed zero order kinetics with that of iodine. Change in ionic strength of the medium showed no effect on the rate of oxidation indicating that reaction occurred between molecular species and there was no ionic species present in the rate determining step. Reaction was affected by the change in temperature and value of energy of activation corresponding to glucose, galactose, D-mannose and L-arabinose were 10.16 kj/mol, 12.17 kj/mol, 14.00 kj/mol and 20.22 kj/mol respectively. (author)

Structural characterization of a rhamnogalacturonan I-arabinan-type I arabinogalactan macromolecule from starfruit (Averrhoa carambola L.).

Science.gov (United States)

Leivas, Carolina Lopes; Iacomini, Marcello; Cordeiro, Lucimara M C

2015-05-05

A structural characterization of polysaccharides obtained from edible tropical fruit named starfruit (Averrhoa carambola L.) was carried out. After fractionation by freeze-thaw and Fehling precipitation, a pectic polysaccharide was obtained. It was composed of rhamnose, arabinose, galactose and uronic acid in the 5.0:72.5:12.1:10.4 molar ratios, respectively. A combination of monosaccharide, GPC, methylation and NMR analysis and enzymatic hydrolysis with endo-β-(1→4)-D-galactanase showed the presence of a rhamnogalacturonan I to which a branched arabinan and a type I arabinogalactan are attached. The arabinan moiety was formed by (1→5)-linked α-L-Araf units in the backbone, branched only at O-3 by (1→2)- and (1→3)-linked α-L-Araf units, while the type I arabinogalactan was formed by (1→4)- and (1→4,6)-linked β-D-Galp units in the backbone with (1→5)-, (1→3,5)- and (1→3)-linked α-L-Araf units as side chains. Copyright © 2014 Elsevier Ltd. All rights reserved.

The FRIABLE1 gene product affects cell adhesion in Arabidopsis.

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Lutz Neumetzler

Full Text Available Cell adhesion in plants is mediated predominantly by pectins, a group of complex cell wall associated polysaccharides. An Arabidopsis mutant, friable1 (frb1, was identified through a screen of T-DNA insertion lines that exhibited defective cell adhesion. Interestingly, the frb1 plants displayed both cell and organ dissociations and also ectopic defects in organ separation. The FRB1 gene encodes a Golgi-localized, plant specific protein with only weak sequence similarities to known proteins (DUF246. Unlike other cell adhesion deficient mutants, frb1 mutants do not have reduced levels of adhesion related cell wall polymers, such as pectins. Instead, FRB1 affects the abundance of galactose- and arabinose-containing oligosaccharides in the Golgi. Furthermore, frb1 mutants displayed alteration in pectin methylesterification, cell wall associated extensins and xyloglucan microstructure. We propose that abnormal FRB1 action has pleiotropic consequences on wall architecture, affecting both the extensin and pectin matrices, with consequent changes to the biomechanical properties of the wall and middle lamella, thereby influencing cell-cell adhesion.

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. Copyright © 2016 Elsevier Ltd. All rights reserved.

Bis-Indole Derivatives for Polysaccharide Compositional Analysis and Chiral Resolution of D-, L-Monosaccharides by Ligand Exchange Capillary Electrophoresis Using Borate-Cyclodextrin as a Chiral Selector

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Wen-Bin Yang

2011-02-01

Full Text Available A series of aldo-bis-indole derivatives (aldo-BINs was prepared by aromatic C-alkylation reactions of aldoses and indole in acetic acid solution. Common monosaccharides such as glucose, mannose, galactose, fucose, xylose, rhamnose, ribose, arabinose and N-acetylglucosamine were smoothly derivatized to form the UV absorbing aldo-BINs. The use of a capillary electrophoretic method to separate these novel aldo-BIN derivatives was established. The capillary electrophoresis conditions were set by using borate buffer (100 mM at high pH (pH 9.0. The limit of determination was assessed to be 25 nM. The enantioseparation of D, L-pairs of aldo-BINs based on chiral ligand-exchange capillary electrophoresis technology was also achieved by using modified hydroxypropyl-β-cyclodextrin as the chiral selector in the presence of borate buffer. This aldose labeling method was applied successfully to the compositional and configurational analysis of saccharides, exemplified by a rapid and efficient method to simultaneously analyze the composition and configuration of saccharides from the medicinal herbs Cordyceps sinensis and Dendrobium huoshanense.

Primary characterization and evaluation of anti ulcerogenic activity of an aqueous extract from callus culture of Cereus peruvianus Mill. (Cactaceae).

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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.

Caracterização física, físico-química, enzimática e de parede celular em diferentes estádios de desenvolvimento da fruta de figueira Physical, chemico-physical, enzymatic and cell wall charazterization during the different development stages of the fig tree fruits

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Carlos Antonio A. Gonçalves

2006-03-01

Full Text Available Com o objetivo de avaliar a caracterização física, físico-química, enzimática e de parede celular, durante os diferentes estádios de desenvolvimento dos frutos da figueira sob irrigação, no norte de Minas Gerais, o presente trabalho foi desenvolvido durante o ciclo de produção 2001/2002, na Unidade de Produção Frutícola da Escola Agrotécnica Federal de Salinas (Eafsal, município de Salinas. Utilizaram-se, neste experimento, plantas com dois anos e meio de idade após o transplantio e com 12 ramos primários (pernadas, bem desenvolvidos e espaçamento de 2,5x1,5 m. O delineamento aplicado foi inteiramente casualizado, com duas repetições e um total de 40 plantas marcadas. Os dados coletados foram referentes ao ciclo de produção 2001/2002, para as plantas podadas em junho. Avaliou-se, durante os diferentes estádios de desenvolvimento dos frutos da figueira, a atividade enzimática, composição química, avaliações físicas, açúcares neutros e compostos de parede celular. À medida que a atividade de polifenoloxidase e peroxidase foi diminuindo, a atividade da poligalacturonase aumentou, no decorrer do desenvolvimento dos frutos. Os frutos atingiram ponto de colheita para a indústria e consumo in natura aos 30 e 75 dias da diferenciação das gemas em sicônio, respectivamente. Ocorreu um aumento significativo nos teores de sólidos solúveis totais, açúcares solúveis totais e redutores durante o desenvolvimento do fruto. O valor de pH e o conteúdo de acidez total titulável variaram muito pouco durante o desenvolvimento do fruto. O diâmetro médio dos frutos foi sempre inferior ao comprimento médio, atingindo 51,99 mm e 59,18 mm, respectivamente, aos 75 dias. Quanto ao peso médio, os frutos atingiram 53,23 g aos 75 dias. Os açúcares neutros predominantes foram a galactose, a arabinose e a xilose, enquanto fucose, manose, glucose e ramnose apresentaram-se em menor quantidade na parede celular durante os

Purification, characterization and anti-aging capacity of mycelia zinc polysaccharide by Lentinus edodes SD-08.

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Wang, Liqin; Wang, Cuiqin; Gao, Xia; Xu, Nuo; Lin, Lin; Zhao, Huajie; Jia, Shouhua; Jia, Le

2015-04-09

In the modern society, aging had been a major problem. People may rely on many medicines to delay it. However, lots of medicines were chemosynthetic, and they would do a bad side-effect on human body. Microbial sources could be used as a potential means of producing natural antioxidants. Lentinus edodes, commercial obtained in daily life, had recently become more attractive in physiological research. Zinc was now considered as a major element in assuring the correct functioning of an organism and essential for maintaining coordination of the major homeostatic networks. To investigate the bioconversion of zinc and the physiological effects of their complex (MZPS), the present studies were processed. Mycelia polysaccharides (MPS) and mycelia zinc polysaccharides (MZPS) of Lentinus edodes SD-08 were extracted by hot water leaching and purified by DEAE-52 cellulose anion-exchange column chromatography separately. The zinc content was determined by flame atomic absorption spectrometry. The evaluation of monosaccharide compositions and proportions used gas chromatogram. The analysis of molecular weight used HPGPC chromatogram. The typical structure of polysaccharide was evaluated by IR spectrum. The antioxidant activities in vitro measured through reducing power, the scavenging effects on hydroxyl radical and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals. The anti-aging activities in vivo measured through the total antioxidant capacity (T-AOC), GSH peroxide (GSH-Px), superoxide dismutase (SOD) and the contents of malondialdehyde (MDA). MPS and MZPS of Lentinus edodes SD-08 were extracted and purified by DEAE-52 cellulose anion-exchange column chromatography separately, and four fractions (MPS-1, MPS-2, MZPS-1 and MZPS-2) were obtained. In addition, MPS composing of rhamnose, arabinose and mannose (molar proportion = 1.75:1.00:3.02) and MZPS containing rhamnose, arabinose, mannose and glucose (molar proportion = 7.19:2.26:1.00:8.39) were investigated by gas chromatography

Preferential uptake of ribose by primitive cells might explain why RNA was favored over its analogs

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Pohorille, Andrew; Wei, Chenyu

Permeation of molecules through membranes is a fundamental process in biological systems, which not only involves mass and signal transfers between the interior of a contemporary cell and its environment, but was also of crucial importance in the origin of life. In the absence of complex protein transporters, nutrients and building blocks of biopolymers must have been able to permeate membranes at sufficient rates to support primordial metabolism and cel-lular reproduction. From this perspective one class of solutes that is of special interest are monosaccharides, which serve not only as nutritional molecules but also as building blocks for information molecules. In particular, ribose is a part of the RNA backbone, but RNA analogs containing a number of other sugars have also been shown to form stable duplexes. Why, among these possibilities, ribose (and, subsequently, deoxyribose) was selected for the backbone of information polymers is still poorly understood. It was recently found that ribose permeates membranes an order of magnitude faster than its diastereomers, arabinose and xylose [1]. On this basis it was hypothesized that differences in membrane permeability to aldopentoses provide a mechanism for preferential delivery of ribose to primitive cells for subsequent, selective incorporation into nucleotides and their polymers. However, the origins of these unusually large differences had not been well understood. We addressed this issue in molecular dynamics simulations combined with free energy calculations. It was found that the free energy barrier for transferring ribose from water to the bilayer is lower by 1.5-2 kcal/mol than the barrier for transferring the other two aldopentoses. The calculated [2] and measured [1] permeability coefficients are in an excellent agreement. The sugar structures that permeate the membrane are -pyranoses, with a possible contribution of the -anomer for arabinose. The furanoid form of ribose is not substantially involved in

Effect of hemicellulolytic enzymes on mesophilic methane fermentation

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Oi, S; Matsui, Y; Iizuka, M; Yamamoto, T

1977-01-01

Mesophilic methane fermentation was examined using soybean seed coat, a waste from soybean processing for oil manufacture, with or without treatment with hemicellulolytic enzymes of Aspergillus niger, and the following results were obtained: (1) The methane fermentation bacteria acclimated to soybean seed coat medium were shown to consume monosaccharides and evolve methane in the following decreasing order: glucose, fructose, mannose > xylose, galactose, glucosamine, galacturonic acid > arabinose. The bacteria were also shown to form methane from a gas mixture of hydrogen and carbon dioxide. (2) In fermentation of soybean seed coat treated with the fungal enzyme, about 70% of the total sugar content as consumed in four weeks, and the gas evolution was about twice that without the fungal enzyme. The gas evolved was composed of 60% methane and 36% carbon dioxide. In general, vigorous evolution of hydrogen and carbon dioxide occurred at a very early stage of fermentation, and was followed by formation of methane. The maximum gas evolution of the enzyme-treated mash took place in 6 days while that of untreated mash occurred one week later. Chemical oxygen demand of the supernatant of the former mash was decreased by fermentation to 7.0% of the initial level.

Purification, Characterization, and Antioxidant Activity of Polysaccharides Isolated from Cortex Periplocae.

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Wang, Xiaoli; Zhang, Yifei; Liu, Zhikai; Zhao, Mingqin; Liu, Pengfei

2017-10-31

In this study, crude Cortex Periplocae polysaccharides (CCPPs) were extracted with water. CCPPs were decolored with AB-8 resin and deproteinated using papain-Sevage methods. Then, they were further purified and separated through DEAE-52 anion exchange chromatography and Sephadex G-100 gel filtration chromatography, respectively. Three main fractions-CPP1, CPP2, and CPP3, (CPPs)-were obtained. The average molecular weights, monosaccharide analysis, surface morphology, and chemical compositions of the CPPs were investigated by high-performance gel permeation chromatography (HPGPC), gas chromatography-mass spectrometry (GC/MS), UV-vis spectroscopy, Fourier transform infrared (FT-IR) spectrum, and nuclear magnetic resonance (NMR). In addition, the antioxidant activities of these three polysaccharides were investigated. The results indicated that all of the CPPs were composed of rhamnose, arabinose, mannose, glucose, and galactose. These three polysaccharides exhibited antioxidant activities in four assays including 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, 2,2'-azino-bis(3-ethyl-benzthiazoline-6-sulfonic acid) (ABTS) radical, reducing power, and total antioxidant activity in vitro. The data indicated that these three polysaccharides could be utilized as potential natural sources of alternative additives in the functional food, cosmetics, and pharmaceutical industries.

Similarity Evaluation of Different Origins and Species of Dendrobiums by GC-MS and FTIR Analysis of Polysaccharides

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Nai-Dong Chen

2015-01-01

Full Text Available GC-MS method combined with FTIR techniques by the analysis of polysaccharide was applied to evaluate the similarity between wild (W and tissue-cultured (TC Dendrobium huoshanense (DHS, Dendrobium officinale (DO, and Dendrobium moniliforme (DM as well as 3 wild Dendrobium spp.: Dendrobium henanense (DHN, Dendrobium loddigesii (DL, and Dendrobium crepidatum (DC. Eight monosaccharides involving xylose, arabinose, rhamnose, glucose, mannose, fructose, galactose, and galacturonic acid were identified in the polysaccharide from each Dendrobium sample while the contents of the monosugars varied remarkably across origins and species. Further similarity evaluation based on GC-MS data showed that the rcor values of different origins of DHS, DO, and DM were 0.831, 0.865, and 0.884, respectively, while the rcor values ranged from 0.475 to 0.837 across species. FTIR files of the polysaccharides revealed that the similarity coefficients between W and TC-DHS, DO, and DM were 88.7%, 86.8%, and 88.5%, respectively, in contrast to the similarity coefficients varying from 57.4% to 82.6% across species. These results suggested that the structures of polysaccharides between different origins of the investigated Dendrobiums might be higher than what we had supposed.

Purification and Structural Characterization of a Novel Water-Soluble Neutral Polysaccharide from Cantharellus cibarius and Its Immunostimulating Activity in RAW264.7 Cells

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Long Chen

2017-01-01

Full Text Available Polysaccharide is one of the important active ingredients of Cantharellus cibarius. The aims of this work were to analyze preliminary characterization and to investigate immunostimulating activity of a novel water-soluble neutral polysaccharide named JP1, which was purified from the fruiting body of Cantharellus cibarius using DEAE-FF chromatography and Sephadex G-100 chromatography. The characteristics of JP1 were determined by HPGPC, FT-IR spectra, gas chromatography, and Congo Red Method. Immunostimulating activity of JP1 was investigated in RAW264.7 cells. Results indicated that JP1 consisted of L-Arabinose, D-Mannose, D-Glucose, and D-Galactose in a molar ratio of 1 : 1.06 : 1.95 : 1.17 with a molecular weight of 336 kDa. JP1 is nontoxic to RAW264.7 cells at this concentration range (62.5–1000 μg/mL. Furthermore, JP1 can promote mouse peritoneal macrophages to secrete NO and enhance the secretion of macrophages’ cytokines IL-6 in RAW264.7 cells. These results suggested that JP1 could have potential immunostimulating activity applications as medicine or functional food.

Some unique features of alkaliphilic anaerobes

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Roof, Erin; Pikuta, Elena; Otto, Christopher; Williams, George; Hoover, Richard

2013-09-01

This article explores two topics involving the examination of four strains of alkaliphilic anaerobes. The first topic was dedicated to detection of the ability of microorganisms to metabolize alternative chirality substrates. Two saccharolytic anaerobic bacteria were chosen for the first experiment: Anaerovirgula multivorans strain SCAT, which is gram positive and spore-forming; and Spirochaeta dissipatitropha, strain ASpC2T, which is gram negative. It was found that both checked sugarlytics were able to use L-ribose and L-arabinose, as growth substrates. The second part was concerned of study a chemolithotrophy in two halo-alkaliphilic sulfate reducing bacteria: Desulfonatornum thiodismutans strain MLF1T and Desulfonatronum lacustre strain Z-7951T. The experiments with lithotrophs had demonstrated that strain MLF1T was capable to grow without any organic source of carbon, while strain Z-7951T had required at least 2 mM sodium acetate for growth. Anaerobic technique was used for preparation of the growth media and maintenance of these bacterial cultures. Standard methods for Gram, spore, and flagella staining were applied for characterization of cytomorphology. In this article, the results of the experiments performed on cytological, physiological, and biochemical levels are presented and discussed.

Co-extraction of soluble and insoluble sugars from energy sorghum based on a hydrothermal hydrolysis process.

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Yu, Qiang; Tan, Xuesong; Zhuang, Xinshu; Wang, Qiong; Wang, Wen; Qi, Wei; Zhou, Guixiong; Luo, Yu; Yuan, Zhenhong

2016-12-01

A process for co-extraction of soluble and insoluble sugars from energy sorghum (ES) was developed based on hydrothermal hydrolysis (HH). Two series of ES were investigated: one (N) with a high biomass yield displayed a higher recalcitrance to sugar release, whereas the second (T) series was characterized by high sugar extraction. The highest total xylose recoveries of 87.2% and 98.7% were obtained for N-11 and T-106 under hydrolysis conditions of 180°C for 50min and 180°C for 30min, respectively. Moreover, the T series displayed higher enzymatic digestibility (ED) than the N series. The high degree of branching (arabinose/xylose ratio) and acetyl groups in the hemicellulose chains of T-106 would be expected to accelerate sugar release during the HH process. In addition, negative correlations between ED and the lignin content, crystallinity index (CrI) and syringyl/guaiacyl (S/G) lignin ratio were observed. Furthermore, finding ways to overcome the thickness of the cell wall and heterogeneity of its chemical composition distribution would make cellulose more accessible to the enzyme. Copyright © 2016 Elsevier Ltd. All rights reserved.

Combinatorial control of gene expression in Aspergillus niger grown on sugar beet pectin.

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Kowalczyk, Joanna E; Lubbers, Ronnie J M; Peng, Mao; Battaglia, Evy; Visser, Jaap; de Vries, Ronald P

2017-09-27

Aspergillus niger produces an arsenal of extracellular enzymes that allow synergistic degradation of plant biomass found in its environment. Pectin is a heteropolymer abundantly present in the primary cell wall of plants. The complex structure of pectin requires multiple enzymes to act together. Production of pectinolytic enzymes in A. niger is highly regulated, which allows flexible and efficient capture of nutrients. So far, three transcriptional activators have been linked to regulation of pectin degradation in A. niger. The L-rhamnose-responsive regulator RhaR controls the production of enzymes that degrade rhamnogalacturonan-I. The L-arabinose-responsive regulator AraR controls the production of enzymes that decompose the arabinan and arabinogalactan side chains of rhamnogalacturonan-II. The D-galacturonic acid-responsive regulator GaaR controls the production of enzymes that act on the polygalacturonic acid backbone of pectin. This project aims to better understand how RhaR, AraR and GaaR co-regulate pectin degradation. For that reason, we constructed single, double and triple disruptant strains of these regulators and analyzed their growth phenotype and pectinolytic gene expression in A. niger grown on sugar beet pectin.

Soil microbial activity, mycelial lengths and physiological groups of bacteria in a heavy metal polluted area

Energy Technology Data Exchange (ETDEWEB)

Nordgren, A; Kauri, T; Baeaeth, E; Soederstroem, B

1986-01-01

The biological effects of heavy metal contamination of coniferous forest soils were studied in the A/sub 01//A/sub 02/ layer around a primary smelter in Northern Sweden. Soil concentrations of 17 elements were determined. Smelter-emitted heavy metals were 5 to 75 times higher in the plot closest to the smelter compared with background levels. Despite emission of sulfur no decrease in pH was found. Bacteria producing acid from maltose, cellobiose, arabinose or xylose and bacteria hydrolyzing starch, pectin, xyland or cellulose decreased 8- to 11-fold due to the soil contamination. Chitin hydrolyzers were 5 times less abundant at the most polluted site compared with background levels. Soil respiration rate and urease activity decreased by about a factor of 4, but phosphatase activity and mycelial lengths were unaffected by the soil contamination. Soil bacteria showed a sigmoidal response to the log of metal concentration in the soil and were affected at a lower pollution level than the other biological variables in the study. A multivariate analysis (partial least squares) showed that soil metal contamination and soil pH were the two environmental factors influencing the soil microorganisms.

High efficiency generalized transduction in Escherichia coli O157:H7 [v1; ref status: indexed, http://f1000r.es/8f

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Martin G Marinus

2013-01-01

Full Text Available Genetic manipulation in enterohemorrhagic E. coli O157:H7 is currently restricted to recombineering, a method that utilizes the recombination system of bacteriophage lambda, to introduce gene replacements and base changes inter alia into the genome. Bacteriophage 933W is a prophage in E. coli O157:H7 strain EDL933, which encodes the genes (stx2AB for the production of Shiga toxin which is the basis for the potentially fatal Hemolytic Uremic Syndrome in infected humans. We replaced the stx2AB genes with a kanamycin cassette using recombineering. After induction of the prophage by ultra-violet light, we found that bacteriophage lysates were capable of transducing to wildtype, point mutations in the lactose, arabinose and maltose genes. The lysates could also transduce tetracycline resistant cassettes. Bacteriophage 933W is also efficient at transducing markers in E. coli K-12. Co-transduction experiments indicated that the maximal amount of transferred DNA was likely the size of the bacteriophage genome, 61 kB. All tested transductants, in both E. coli K-12 and O157:H7, were kanamycin-sensitive indicating that the transducing particles contained host DNA.

Characterization and Bioactivity of Polysaccharides Obtained from Pine Cones of Pinus koraiensis by Graded Ethanol Precipitation

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Xin Yang

2013-08-01

Full Text Available Pinus koraiensis polysaccharides (PKP were extracted by hot water from P. koraiensis pine cones. Five polysaccharide fractions named PKP-A, PKP-B, PKP-C, PKP-D and PKP-E were successfully separated at final ethanol concentrations of 30%, 50%, 60%, 70% and 80%, respectively. HPLC, FT-IR, GC-MS and automatic amino-acid analysis were applied to investigate their chemical characteristics. Monosaccharide component analysis indicated that the five fractions were all composed of d-ribose, l-rhamnose, l-arabinose, d-xylose, d-mannose, d-glucose and d-galactose, but their molar ratios were quite different. HPLC results revealed that the polysaccharides precipitated by higher concentrations of ethanol solution had lower molecular masses. Moreover, the antioxidant activities of the five fractions were studied on the basis of hydroxyl radical and ABTS radical scavenging tests. The five graded polysaccharide fractions exhibited good inhibitory power, and MTT tests in vitro showed the IC50 of PKP-A and PKP-E were 1,072.5 and 2,070.0 μg·mL−1, respectively. These results demonstrated that the PKP could be a potential source of natural antioxidants or dietary supplements.

Engineering and Evolution of Saccharomyces cerevisiae to Produce Biofuels and Chemicals.

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Turner, Timothy L; Kim, Heejin; Kong, In Iok; Liu, Jing-Jing; Zhang, Guo-Chang; Jin, Yong-Su

To mitigate global climate change caused partly by the use of fossil fuels, the production of fuels and chemicals from renewable biomass has been attempted. The conversion of various sugars from renewable biomass into biofuels by engineered baker's yeast (Saccharomyces cerevisiae) is one major direction which has grown dramatically in recent years. As well as shifting away from fossil fuels, the production of commodity chemicals by engineered S. cerevisiae has also increased significantly. The traditional approaches of biochemical and metabolic engineering to develop economic bioconversion processes in laboratory and industrial settings have been accelerated by rapid advancements in the areas of yeast genomics, synthetic biology, and systems biology. Together, these innovations have resulted in rapid and efficient manipulation of S. cerevisiae to expand fermentable substrates and diversify value-added products. Here, we discuss recent and major advances in rational (relying on prior experimentally-derived knowledge) and combinatorial (relying on high-throughput screening and genomics) approaches to engineer S. cerevisiae for producing ethanol, butanol, 2,3-butanediol, fatty acid ethyl esters, isoprenoids, organic acids, rare sugars, antioxidants, and sugar alcohols from glucose, xylose, cellobiose, galactose, acetate, alginate, mannitol, arabinose, and lactose.

High resolution visualization and exo-proteomics reveal the physiological role of XlnR and AraR in plant biomass colonization and degradation by Aspergillus niger.

Science.gov (United States)

Kowalczyk, Joanna E; Khosravi, Claire; Purvine, Samuel; Dohnalkova, Alice; Chrisler, William B; Orr, Galya; Robinson, Errol; Zink, Erika; Wiebenga, Ad; Peng, Mao; Battaglia, Evy; Baker, Scott; de Vries, Ronald P

2017-11-01

In A. niger, two transcription factors, AraR and XlnR, regulate the production of enzymes involved in degradation of arabinoxylan and catabolism of the released l-arabinose and d-xylose. Deletion of both araR and xlnR in leads to reduced production of (hemi)cellulolytic enzymes and reduced growth on arabinan, arabinogalactan and xylan. In this study, we investigated the colonization and degradation of wheat bran by the A. niger reference strain CBS 137562 and araR/xlnR regulatory mutants using high-resolution microscopy and exo-proteomics. We discovered that wheat bran flakes have a 'rough' and 'smooth' surface with substantially different affinity towards fungal hyphae. While colonization of the rough side was possible for all strains, the xlnR mutants struggled to survive on the smooth side of the wheat bran particles after 20 and 40 h post inoculation. Impaired colonization ability of the smooth surface of wheat bran was linked to reduced potential of ΔxlnR to secrete arabinoxylan and cellulose-degrading enzymes and indicates that XlnR is the major regulator that drives colonization of wheat bran in A. niger. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

Physicochemical properties and antidiabetic effects of a polysaccharide from corn silk in high-fat diet and streptozotocin-induced diabetic mice.

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Pan, Yuxiang; Wang, Cong; Chen, Zhongqin; Li, Weiwei; Yuan, Guoqi; Chen, Haixia

2017-05-15

This study aimed to investigate the physicochemical properties and antidiabetic effects of a polysaccharide obtained from corn silk (PCS2). PCS2 was isolated and the physicochemical properties were characterized. The hypoglycemic effects were determined using the high-fat diet and streptozocin induced type 2 diabetic mellitus (T2DM) insulin resistance mice. The results showed that PCS2 was a heteropolysaccharide with the average molecular weight of 45.5kDa. PCS2 was composed of d-galactose, d-mannose, d-(+)-glucose, d-(+)-xylose, l-arabinose and l-rhamnose. PCS2 treatment significantly reduced the body weight loss, decreased blood glucose and serum insulin levels, and improved glucose intolerance (P<0.05). The levels of serum lipid profile were regulated and the levels of glycated serum protein, non-esterified fatty acid were decreased significantly (P<0.01). The activities of superoxide dismutase, glutathione peroxidase and catalase were notably improved (P<0.05). PCS2 also exerted cytoprotective action from histopathological observation. These results suggested that PCS2 could be a good candidate of functional food or medicine for T2DM treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Enzymolysis-ultrasonic assisted extraction, chemical characteristics and bioactivities of polysaccharides from corn silk.

Science.gov (United States)

Chen, Shuhan; Chen, Haixia; Tian, Jingge; Wang, Jia; Wang, Yanwei; Xing, Lisha

2014-01-30

An enzymolysis-ultrasonic assisted extraction (EUAE) procedure of corn silk polysaccharides (CSPS) was established and the physicochemical properties, antioxidant and anticancer activities of CSPS were studied. Orthogonal test and response surface methodology were applied to optimize the extraction parameters. The optimum enzymolysis and ultrasonic conditions were cellulase content of 7.5% for 150 min at 55 °C and liquid-solid ratio of 31.8 for 34.2 min at 66.3 °C, respectively. Under these conditions, the yield of CSPS increased from 4.56% to 7.10%. CSPS obtained by hot water and EUAE were composed of rhamnose, arabinose, xylose, mannose, galactose and glucose with molecular ratios of 4.17:17.33:5.59:18.65:19.11:35.14 and 8.83:15.77:7.92:12.39:11.15:43.94, respectively. Their molecular weight distributions were 10.52 × 10(4) and 6.88 × 10(4)Da, respectively. CSPS obtained by EUAE showed morphological and conformation changes and higher antioxidant and anticancer activities compared with CSPS extracted by hot water. Copyright © 2013 Elsevier Ltd. All rights reserved.

In Vitro Antioxidant, Anticoagulant and Antimicrobial Activity and in Inhibition of Cancer Cell Proliferation by Xylan Extracted from Corn Cobs

Science.gov (United States)

Melo-Silveira, Raniere Fagundes; Fidelis, Gabriel Pereira; Costa, Mariana Santana Santos Pereira; Telles, Cinthia Beatrice Silva; Dantas-Santos, Nednaldo; de Oliveira Elias, Susana; Ribeiro, Vanessa Bley; Barth, Afonso Luis; Macedo, Alexandre José; Leite, Edda Lisboa; Rocha, Hugo Alexandre Oliveira

2012-01-01

Xylan is one of most abundant polymer after cellulose. However, its potential has yet to be completely recognized. Corn cobs contain a considerable reservoir of xylan. The aim of this work was to study some of the biological activities of xylan obtained from corn cobs after alkaline extraction enhanced by ultrasonication. Physical chemistry and infrared analyses showed 130 kDa heteroxylan containing mainly xylose:arabinose: galactose:glucose (5.0:1.5:2.0:1.2). Xylan obtained exhibited total antioxidant activity corresponding to 48.5 mg of ascorbic acid equivalent/g of xylan. Furthermore, xylan displayed high ferric chelating activity (70%) at 2 mg/mL. Xylan also showed anticoagulant activity in aPTT test. In antimicrobial assay, the polysaccharide significantly inhibited bacterial growth of Klebsiella pneumoniae. In a test with normal and tumor human cells, after 72 h, only HeLa tumor cell proliferation was inhibited (p < 0.05) in a dose-dependent manner by xylan, reaching saturation at around 2 mg/mL, whereas 3T3 normal cell proliferation was not affected. The results suggest that it has potential clinical applications as antioxidant, anticoagulant, antimicrobial and antiproliferative compounds. PMID:22312261

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. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

Matrix composition and community structure analysis of a novel bacterial pyrite leaching community.

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Ziegler, Sibylle; Ackermann, Sonia; Majzlan, Juraj; Gescher, Johannes

2009-09-01

Here we describe a novel bacterial community that is embedded in a matrix of carbohydrates and bio/geochemical products of pyrite (FeS(2)) oxidation. This community grows in stalactite-like structures--snottites--on the ceiling of an abandoned pyrite mine at pH values of 2.2-2.6. The aqueous phase in the matrix contains 200 mM of sulfate and total iron concentrations of 60 mM. Micro-X-ray diffraction analysis showed that jarosite [(K,Na,H(3)O)Fe(3)(SO(4))(2)(OH)(6)] is the major mineral embedded in the snottites. X-ray absorption near-edge structure experiments revealed three different sulfur species. The major signal can be ascribed to sulfate, and the other two features may correspond to thiols and sulfoxides. Arabinose was detected as the major sugar component in the extracellular polymeric substance. Via restriction fragment length polymorphism analysis, a community was found that mainly consists of iron oxidizing Leptospirillum and Ferrovum species but also of bacteria that could be involved in dissimilatory sulfate and dissimilatory iron reduction. Each snottite can be regarded as a complex, self-contained consortium of bacterial species fuelled by the decomposition of pyrite.

Identification of a sugar gustatory receptor and its effect on fecundity of the brown planthopper Nilaparvata lugens.

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Chen, Wei-Wen; Kang, Kui; Yang, Pan; Zhang, Wen-Qing

2017-11-27

In insects, the gustatory system plays a crucial role in multiple physiological behaviors, including feeding, toxin avoidance, courtship, mating and oviposition. Gustatory stimuli from the environment are recognized by gustatory receptors. To date, little is known about the function of gustatory receptors in agricultural pest insects. In this study, we cloned a sugar gustatory receptor gene, NlGr11, from the brown planthopper (BPH), Nilaparvata lugens (Stål), a serious pest of rice in Asia; we then identified its ligands, namely, fructose, galactose and arabinose, by calcium imaging assay. After injection of NlGr11 double-stranded RNA, we found that the number of eggs laid by BPH decreased. Moreover, we found that NlGr11 inhibited the phosphorylation of adenosine monophosphate-activated protein kinase (AMPK) and promoted the phosphorylation of protein kinase B (AKT). These findings demonstrated that NlGr11 could accelerate the fecundity of BPH through AMPK- and AKT-mediated signaling pathways. This is the first report to indicate that a gustatory receptor modulates the fecundity of insects and that the receptor could be a potential target for pest control. © 2017 Institute of Zoology, Chinese Academy of Sciences.

Anti-tumoral effect of the mitochondrial target domain of Noxa delivered by an engineered Salmonella typhimurium.

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Jae-Ho Jeong

Full Text Available Bacterial cancer therapy relies on the fact that several bacterial species are capable of targeting tumor tissue and that bacteria can be genetically engineered to selectively deliver therapeutic proteins of interest to the targeted tumors. However, the challenge of bacterial cancer therapy is the release of the therapeutic proteins from the bacteria and entry of the proteins into tumor cells. This study employed an attenuated Salmonella typhimurium to selectively deliver the mitochondrial targeting domain of Noxa (MTD as a potential therapeutic cargo protein, and examined its anti-cancer effect. To release MTD from the bacteria, a novel bacterial lysis system of phage origin was deployed. To facilitate the entry of MTD into the tumor cells, the MTD was fused to DS4.3, a novel cell-penetrating peptide (CPP derived from a voltage-gated potassium channel (Kv2.1. The gene encoding DS4.3-MTD and the phage lysis genes were placed under the control of PBAD , a promoter activated by L-arabinose. We demonstrated that DS4.3-MTD chimeric molecules expressed by the Salmonellae were anti-tumoral in cultured tumor cells and in mice with CT26 colon carcinoma.

Reclassification of Lactobacillus kimchii and Lactobacillus bobalius as later subjective synonyms of Lactobacillus paralimentarius.

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Pang, Huili; Kitahara, Maki; Tan, Zhongfang; Wang, Yanping; Qin, Guangyong; Ohkuma, Moriya; Cai, Yimin

2012-10-01

Characterization and identification of strain CW 1 ( = JCM 17161) isolated from corn silage were performed. Strain CW 1 was a Gram-positive, catalase-negative and homofermentative rod that produced the DL-form of lactic acid. This strain exhibited more than 99.6% 16S rRNA gene sequence similarity and greater than 82% DNA-DNA reassociation with type strains of Lactobacillus kimchii, L. bobalius and L. paralimentarius. To clarify the taxonomic positions of these type strains, phenotypic characterization, 16S rRNA gene sequencing, ribotyping and DNA-DNA relatedness were examined. The three type strains displayed different L-arabinose, lactose, melibiose, melezitose, raffinose and N-acetyl-β-glucosaminidase fermentation patterns. Phylogenetic analysis showed that L. paralimentarius is a closer neighbour of L. kimchii and L. bobalius, sharing 99.5-99.9% 16S rRNA gene sequence similarity, which was confirmed by the high DNA-DNA relatedness (≥82%) between L. paralimentarius JCM 10415(T), L. bobalius JCM 16180(T) and L. kimchii JCM 10707(T). Therefore, it is proposed that L. kimchii and L. bobalius should be reclassified as later synonyms of L. paralimentarius.

Nitrogen-fixing and cellulose-producing Gluconacetobacter kombuchae sp. nov., isolated from Kombucha tea.

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Dutta, Debasree; Gachhui, Ratan

2007-02-01

A few members of the family Acetobacteraceae are cellulose-producers, while only six members fix nitrogen. Bacterial strain RG3T, isolated from Kombucha tea, displays both of these characteristics. A high bootstrap value in the 16S rRNA gene sequence-based phylogenetic analysis supported the position of this strain within the genus Gluconacetobacter, with Gluconacetobacter hansenii LMG 1527T as its nearest neighbour (99.1 % sequence similarity). It could utilize ethanol, fructose, arabinose, glycerol, sorbitol and mannitol, but not galactose or xylose, as sole sources of carbon. Single amino acids such as L-alanine, L-cysteine and L-threonine served as carbon and nitrogen sources for growth of strain RG3T. Strain RG3T produced cellulose in both nitrogen-free broth and enriched medium. The ubiquinone present was Q-10 and the DNA base composition was 55.8 mol% G+C. It exhibited low values of 5.2-27.77 % DNA-DNA relatedness to the type strains of related gluconacetobacters, which placed it within a separate taxon, for which the name Gluconacetobacter kombuchae sp. nov. is proposed, with the type strain RG3T (=LMG 23726T=MTCC 6913T).

Roseomonas, a new genus associated with bacteremia and other human infections.

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Rihs, J D; Brenner, D J; Weaver, R E; Steigerwalt, A G; Hollis, D G; Yu, V L

1993-01-01

In the 1980s, a pink bacterium different from species of the genus Methylobacterium was implicated in human infection. Using biochemical tests and DNA hybridization, we examined 42 strains of pink-pigmented, gram-negative bacteria that were not members of the genus Methylobacterium. The isolates included 6 strains each of CDC "pink coccoid" groups I, II, III, and IV; 10 isolates from Gilardi's "unnamed taxon"; and 8 blood isolates from ill, debilitated, or immunosuppressed patients. The DNA hybridization studies supported the creation of six genomospecies encompassing the 42 strains. Reactions for esculin hydrolysis, glycerol oxidation, and D-mannose oxidation enabled separation of genomospecies 1 through 4. These tests, as well as motility, nitrate reduction, citrate utilization, and oxidation of L-arabinose, D-galactose, and D-xylose, differentiated genomospecies 5 and 6 from each other and from genomospecies 1 through 4. These organisms were susceptible in vitro to the aminoglycosides, tetracycline, and imipenem and generally susceptible to the quinolones. We propose the new genus, Roseomonas, for these bacteria to include three named species, Roseomonas gilardii sp. nov., Roseomonas cervicalis sp. nov., and Roseomonas fauriae sp. nov., and three unnamed genomospecies. Images PMID:8308122

Fermentative lactic acid production from coffee pulp hydrolysate using Bacillus coagulans at laboratory and pilot scales.

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Pleissner, Daniel; Neu, Anna-Katrin; Mehlmann, Kerstin; Schneider, Roland; Puerta-Quintero, Gloria Inés; Venus, Joachim

2016-10-01

In this study, the lignocellulosic residue coffee pulp was used as carbon source in fermentative l(+)-lactic acid production using Bacillus coagulans. After thermo-chemical treatment at 121°C for 30min in presence of 0.18molL(-1) H2SO4 and following an enzymatic digestion using Accellerase 1500 carbon-rich hydrolysates were obtained. Two different coffee pulp materials with comparable biomass composition were used, but sugar concentrations in hydrolysates showed variations. The primary sugars were (gL(-1)) glucose (20-30), xylose (15-25), sucrose (5-11) and arabinose (0.7-10). Fermentations were carried out at laboratory (2L) and pilot (50L) scales in presence of 10gL(-1) yeast extract. At pilot scale carbon utilization and lactic acid yield per gram of sugar consumed were 94.65% and 0.78gg(-1), respectively. The productivity was 4.02gL(-1)h(-1). Downstream processing resulted in a pure formulation containing 937gL(-1)l(+)-lactic acid with an optical purity of 99.7%. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

[Comparison on polysaccharide content and PMP-HPLC fingerprints of polysaccharide in stems and leaves of Dendrobium officinale].

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Zhou, Gui-Fen; Pang, Min-Xia; Chen, Su-Hong; Lv, Gui-Yuan; Yan, Mei-Qiu

2014-03-01

In order to provide scientific basics for exploitation and sufficient application of Dendrobium officinale leaves resources, the phenol-sulfuric acid method was applied to determine the polysaccharide content. The monosaccharides were derivated by PMP and the derivatives were identified by HPLC-DAD-ESI-MS(n) and the contents of mannose and glucose were determined simultaneously. Similarity evaluation system for chromatographic fingerprint of traditional Chinese medicine (2004A) was employed to generate the mean chromatogram and similarity analysis of the samples was carried out. The results demonstrated that polysaccharide content, monosaccharide compositions and composition ratio had an obvious difference between stems and leaves. The polysaccharide content of stems was higher than that of leaves. Monosaccharide composition in leaf was significantly different from that in stem. The polysaccharide from stems was composed of mannose and glucose, however the polysaccharide of leaves was acid heteropolysaccharide and was mainly composed of five monosaccharides, including mannose, galacturonic acid, glucose, galactose and arabinose. The similarity value of the 14 batches was above 0.9, indicating that similarity of fingerprints among different samples was high. The study can provide evidence for expanding the medicinal parts of D. officinale.

[Structural analysis and anti-tumor activity in vivo of polysaccharide APS-2a from Angelica sinensis].

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Cao, Wei; Li, Xiao-Qiang; Hou, Ying; Fan, Hui-Ting; Zhang, Xiao-Nan; Mei, Qi-Bing

2008-02-01

The polysaccharide APS-2a was isolated from Angelica sinensis (Oliv.) Diels through water extraction, deprotein, ethanol precipitation and DEAE-sephades A-25 column chromatography respectively,and was further purified by Sephacryl S-400 and Sephadex G-100 column chromatography. The phenol-sulfuric acid assay and Bradford method were used to determine the contents of carbohydrate and protein, respectively. The molecular weight was carried out with high-performance size exclusion chromatography (HPSEC) combined with a differential refractometer detector. The monosaccharide compositions were determined by gas chromatography after complete hydrolysis with acid. The models of mice transplanted sarcoma S-180 were used to study the anti-tumor effects in vivo. Thymus indexes, spleen indexes were determined. The HPSEC result showed the APS-2a was a single homogeneous component and its weight average molecular weight was 7.4 x 10(5) Da. The monosaccharide composition of APS-2a was glucose, galactose, arabinose, rhamnose, galcturonic acid. Furthermore, APS-2a (20.50 mg/kg) could inhibit the proliferation of tumor cells in mice transplanted S-180. The thymus indexes and spleen indexes in the groups treated with APS-2a were higher than control group.

Structural characterization of sulfated arabinans extracted from Cladophora glomerata Kützing and their macrophage activation.

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Surayot, Utoomporn; Hun Lee, Ju; Kanongnuch, Chartchai; Peerapornpisal, Yuwadee; Park, WooJung; You, SangGuan

2016-05-01

Water-soluble sulfated heteropolysaccharides were extracted from Cladophora glomerata Kützing and fractionated by ion-exchange chromatography, which yielded two subfractions, F1 and F2. The crude and fractionated polysaccharides (F1 and F2) mostly consisted of carbohydrates (62.8-74.5%) with various amounts of proteins (9.00-17.3%) and sulfates (16.5-23.5%), including different levels of arabinose (41.7-54.4%), galactose (13.5-39.0%), glucose (0.80-10.6%), xylose (6.84-13.4%), and rhamnose (0.20-2.83%). Based on the size exclusion chromatography (SEC) profiles, the crude and fractions mainly contained one peak with shoulders having molecular weight (Mw) ranges of 358-1,501 × 10(3). The F1 fraction stimulated RAW264.7 cells to produce considerable amounts of nitric oxide and cytokines compared to the crude and F2 fraction. The backbone of the most potent immunostimulating fraction (F1) was α-(1→4)-L-arabinopyranoside with galactose and xylose residues as branches at O-2 position, and sulfates mainly at O-2 position as well.

Some physico-chemical properties of Prunus armeniaca L. gum exudates.

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Fathi, Morteza; Mohebbi, Mohebbat; Koocheki, Arash

2016-01-01

The objectives of this paper were to investigate some physicochemical properties of Prunus armeniaca L. gum exudates (PAGE). PAGE had, on average, 66.89% carbohydrate, 10.47% uronic acids, 6.9% moisture (w.b.), 2.91% protein, 4% ash and 1.59% fat. PAGE was composed of monosaccharides including l-arabinose, d-galactose, xylose, mannose and rhamnose in molar percentages of 41.52%, 23.72%, 17.82%, 14.40% and 2.54%, respectively. Elemental analysis showed that PAGE had high values of nutrients. FTIR analysis demonstrated the presence of carboxyl, hydroxyl and methyl groups and glycoside bonds. The weight average molecular weight, number average molecular weight and polydispersity index were found to be approximately 5.69 × 10(5)g/mol, 4.33 g/mol and 1.31, respectively. Rheological measurement of PAGE solutions as a function of concentration (8, 10 and 12% (w/w)) and temperature (10, 20, 30 and 40°C) demonstrated that the gum solutions had a non Newtonian shear thinning behaviour. Intrinsic viscosity for PAGE in deionized water was 3.438 dl/g based on Kramer equation. Copyright © 2015 Elsevier B.V. All rights reserved.

Vibrio rotiferianus sp. nov., isolated from cultures of the rotifer Brachionus plicatilis.

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Gomez-Gil, B; Thompson, F L; Thompson, C C; Swings, J

2003-01-01

Five Gram-negative bacterial strains, oxidase-positive, motile by means of more than one polar flagella, facultative anaerobe, arginine dihydrolase-negative, lysine- and omithine decarboxylase-positive, sensitive to the vibriostatic agent O/129, were isolated from a flow-through rotifer culture system in Gent, Belgium, and previously characterized by fluorescent amplified fragment length polymorphism. Comparison of the 16S rDNA sequence of strain LMG 21460T indicated close relationships (approximately 99% similarity) to Vibrio campbellii, Vibrio harveyi, Vibrio alginolyticus and Vibrio parahaemolyticus. However, DNA hybridization experiments revealed similarity values below 70% with its closest species V. campbellii and V. harveyi. Additionally, the analysed strains differ from related Vibrio species by the utilization of melibiose and production of acid from L-arabinose and amygdalin. Among the strains analysed, differences were observed in some phenotypic characters, particularly susceptibility to ampicillin, polymyxin B and amikacin, and urease activity. The major fatty acids identified were 16:0, 18:1 omega7c, 14:0, 12:0 3-OH and 18:0. Vibrio rotiferianus sp. nov. is proposed, with type strain LMG 21460T (=CAIM 577T); it has a DNA G+C content of 44.5 +/- 0.01 mol%.

Structural and thermal characterization of hemicelluloses isolated by organic solvents and alkaline solutions from Tamarix austromongolica.

Science.gov (United States)

Sun, Yong-Chang; Wen, Jia-Long; Xu, Feng; Sun, Run-Cang

2011-05-01

Three organosolv and three alkaline hemicellulosic fractions were prepared from lignocellulosic biomass of the fast-growing shrub Tamarix austromongolica (Tamarix Linn.). Sugar analysis revealed that the organosolv-soluble fractions contained a higher content of glucose (33.7-6.5%) and arabinose (14.8-5.6%), and a lower content of xylose (62.2-54.8%) than the hemicellulosic fractions isolated with aqueous alkali solutions. A relatively high concentration of alkali resulted in a decreasing trend of the xylose/4-O-methyl-D-glucuronic acid ratio in the alkali-soluble fractions. The results of NMR analysis supported a major substituted structure based on a linear polymer of β-(1→4)-linked d-xylopyranosyl residues, having ramifications of α-L-arabinofuranose and 4-O-methyl-D-glucuronic acid residues monosubstituted at O-3 and O-2, respectively. Thermogravimetric analysis revealed that one step of major mass loss occurred between 200-400°C, as hemicelluloses devolatilized with total volatile yield of about 55%. It was found that organosolv-soluble fractions are more highly ramified, and showed a higher thermal stability than the alkali-soluble fractions. Copyright © 2011 Elsevier Ltd. All rights reserved.

Characterization of active polysaccharides of HemoHIM

International Nuclear Information System (INIS)

Shin, Kwang Sun; Shin, Myeong Suk; Bae, Beom Seon; Hwang, Yong Cheol; Ryu, Kwang Won

2007-07-01

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

Polysaccharide peptide isolated from grass-cultured Ganoderma lucidum induces anti-proliferative and pro-apoptotic effects in the human U251 glioma cell line.

Science.gov (United States)

Wang, Chunhua; Lin, Dongmei; Chen, Quan; Lin, Shuqian; Shi, Songsheng; Chen, Chunmei

2018-04-01

The Ganoderma lucidum ( G. lucidum ) mushroom is one of the most extensively studied functional foods, known for its numerous health benefits, including the inhibition of tumor cell growth. The present study assessed the anti-proliferative and pro-apoptotic activity of a novel G. lucidum polysaccharide peptide (GL-PP) in human glioma U251 cells, which was purified from grass-cultured G. lucidum . GL-PP is a glycopeptide with an average molecular weight of 42,635 Da and a polysaccharide-to-peptide ratio of 88.70:11.30. The polysaccharides were composed of l-arabinose, d-mannose and d-glucose at a molar ratio of 1.329:0.372:2.953 and a total of 17 amino acids were detected. The results of the current study demonstrated that GL-PP significantly inhibited U251 cellular proliferation. The proportion of G 0 /G 1 phase cells and sub-G 1 phase cells significantly increased as the concentration of GL-PP increased, as did the activity of caspase-3. These results indicate that GL-PP directly inhibited human glioma U251 proliferation by inducing cell cycle arrest and promoting apoptosis.

Karakteristik dan Patogenisitas Streptococcus Agalactiae Tipe ?-hemolitik dan Non-hemolitik pada Ikan Nila

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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.

Antioxidant activity and optimization of extraction of polysaccharide from the roots of Dipsacus asperoides.

Science.gov (United States)

Tan, Li-Hong; Zhang, Dan; Yu, Bao; Zhao, Sheng-Ping; Wang, Jian-Wei; Yao, Ling; Cao, Wei-Guo

2015-11-01

Polysaccharide extraction from Dipsacus asperoides roots (DAP) was proved to possess strong antioxidant activities, including 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-Azobis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS) radical scavenging activities, inhibiting β-carotene bleaching and strong reducing power. Cell assay demonstrated that the crude DAP possessed antioxidant activity and were effective against H2O2-induced L02 cells injury. Then, response surface methodology (RSM) was applied to optimize the ultrasonic extraction of DAP. The optimum variables given by central composite design (CCD) were as follows: ratio of water to raw material, 38.61mL/g; ultrasonic power, 308.68W; extraction time, 38.61min; and extraction temperature, 89°C. Under these conditions, the maximum yield of DAP obtained was 7.12±0.45%. Moreover, high performance liquid chromatography (HPLC) analysis suggested that the monosaccharide compositions of DAP contained primarily mannose, ribose, glucose, galactose, xylose and arabinose, with a molar ratio of 0.22:0.48:2.29:0.34:1.39:1.41. The results of the present study showed that DAP could be considered as potential sources of natural antioxidants. Copyright © 2015 Elsevier B.V. All rights reserved.

Antiglycemic Effect of Water Extractable Arabinoxylan from Wheat Aleurone and Bran

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Lovemore Nkhata Malunga

2017-01-01

Full Text Available The studies on the effects of arabinoxylan (AX polysaccharides on postprandial glucose response have resulted in contrasting results owing to the diversity in AX structures. Four water extractable AX (WEAX extracts obtained from wheat aleurone and bran were used to investigate (a the effect of AX on activities of α-amylase and α-glucosidase, (b influence of AX chemical composition on their inhibition potency, and (c kinetics of enzyme inhibition. α-Amylase activity was not significantly affected by the presence WEAX fractions regardless of type or concentration. WEAX inhibited α-glucosidase activity only when maltose was used as a substrate but not sucrose. The IC50 values of WEAX (4.88±0.3–10.14±0.5 mg/mL were highly correlated to ferulic acid content (R=-0.89, arabinose to xylose ratio (R=-0.67, and relative proportions of xylose being unsubstituted (R=0.69, disubstituted (R=-0.63, and monosubstituted (R=-0.76. The Lineweaver–Burk plot suggested an uncompetitive enzyme inhibition mode. Thus, our results suggest that antiglycemic properties of WEAX may be derived from direct inhibition of α-glucosidase activity.

Substituted galacturonan from starfruit: Chemical structure and antinociceptive and anti-inflammatory effects.

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Leivas, Carolina L; Nascimento, Leandro F; Barros, Wellinghton M; Santos, Adair R S; Iacomini, Marcello; Cordeiro, Lucimara M C

2016-03-01

Starfruit (Averrhoa carambola L.) is an edible tropical fruit, which is usually consumed as a fresh table fruit or as fruit juice. It also exhibits various pharmacological activities. In this study, polysaccharides were extracted with boiling water and purified by freeze-thawing and Fehling treatments. After purification steps, a homogenous fraction was obtained. It was analyzed by sugar composition, gel permeation chromatography, methylation, and two-dimensional nuclear magnetic resonance (2D NMR) spectroscopy analyses. It comprised arabinose (Ara), galactose (Gal), and galacturonic acid (GalA) in a molar ratio of 12.3:1.7:86.0. Methylation and NMR spectroscopy analyses showed that it contained a substituted galacturonan composed of (1→4)-linked α-D-Galp A units branched at O-2 by (1→5)-linked α-L-Araf and terminal α-L-Araf and α-D-Galp A units. The effect of PFSCW (10-300mg/kg, i.p.) on nocifensive behavior induced by intraplantar injection of formalin in mice was evaluated. The fraction demonstrated antinociceptive and anti-inflammatory properties, suggesting that it may be useful in therapeutic intervention for the management of inflammatory pain. Copyright © 2015. Published by Elsevier B.V.

Reevaluation of the phenol-sulfuric acid reaction for the estimation of hexoses and pentoses.

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Rao, P; Pattabiraman, T N

1989-08-15

Evidence is provided to show that in the conventional phenol-sulfuric acid reaction procedure, phenol underwent sulfonation in situ and the phenolsulfonic acid formed decreased the color intensity for hydroxymethyl furfural (HMF), furfural, and many hexoses and pentoses tested. A modified method is described to overcome this problem in which phenol was added after the dehydration of carbohydrates by sulfuric acid and after cooling the system. The color intensity around 475-485 nm for different compounds was fairly proportional to the amount of furfural derivatives (absorption at 310-320 nm) formed from the sugars in the modified method unlike in the conventional procedure. The studies also show that for condensation of HMF derivatives with phenol, heat is not necessary. The color intensity in the modified method also increased compared to that in the conventional method. The increase in the modified method compared to that in the conventional method was 6.0-fold for furfural, 9.1-fold for hydroxymethyl furfural, 3.7-fold for fructose, 2.3-fold for xylose, and 2.0-fold for glucose and arabinose. The possible reasons for this differential increase are discussed.

Raman spectroscopy based screening of IgG positive and negative sera for dengue virus infection

Science.gov (United States)

Bilal, M.; Saleem, M.; Bial, Maria; Khan, Saranjam; Ullah, Rahat; Ali, Hina; Ahmed, M.; Ikram, Masroor

2017-11-01

A quantitative analysis for the screening of immunoglobulin-G (IgG) positive human sera samples is presented for the dengue virus infection. The regression model was developed using 79 samples while 20 samples were used to test the performance of the model. The R-square (r 2) value of 0.91 was found through a leave-one-sample-out cross validation method, which shows the validity of this model. This model incorporates the molecular changes associated with IgG. Molecular analysis based on regression coefficients revealed that myristic acid, coenzyme-A, alanine, arabinose, arginine, vitamin C, carotene, fumarate, galactosamine, glutamate, lactic acid, stearic acid, tryptophan and vaccenic acid are positively correlated with IgG; while amide III, collagen, proteins, fatty acids, phospholipids and fucose are negatively correlated. For blindly tested samples, an excellent agreement has been found between the model predicted, and the clinical values of IgG. The parameters, which include sensitivity, specificity, accuracy and the area under the receiver operator characteristic curve, are found to be 100%, 83.3%, 95% and 0.99, respectively, which confirms the high quality of the model.

Protective Effects of Extracellular and Intracellular Polysaccharides on Hepatotoxicity by Hericium erinaceus SG-02.

Science.gov (United States)

Cui, Fangyuan; Gao, Xia; Zhang, Jianjun; Liu, Min; Zhang, Chen; Xu, Nuo; Zhao, Huajie; Lin, Lin; Zhou, Meng; Jia, Le

2016-09-01

The protective effects of extracellular and intracellular polysaccharides from Hericium erinaceus SG-02 on the CCl4-induced hepatic injury of mice were investigated in this work. By the analysis of GC, the extracellular polysaccharides (EPS) were composed of arabinose, mannose, galactose, and glucose with a ratio of 1:7:14:52, and the composition of intracellular polysaccharides (IPS) was rhamnose, xylose, mannose, galactose, and glucose with a ratio of 3:4:7:14:137. The model of hepatic injury of mice was induced by CCl4 and three tested levels (200, 400, and 800 mg/kg) of EPS and IPS were set as the experimental group. Results showed that the aspartate aminotransferase and glutamic pyruvic transaminase activities in serum were reduced by the supplement of EPS and IPS, while the blood lipid levels including cholesterol, triglyceride, and albumin were improved. In liver tissue, the lipid peroxidation and malondialdehyde were largely decreased, and the superoxide dismutase and catalase activities were significantly increased. The evidence demonstrated that the EPS and IPS of H. erinaceus SG-02 were protective for liver injury. The histopathological observations of mice liver slices indicated that EPS and IPS had obvious effects on liver protection.

Ultrasound assisted extraction of polysaccharides from Lentinus edodes and its anti-hepatitis B activity in vitro.

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Zhao, Yong-Ming; Yang, Jian-Ming; Liu, Ying-Hui; Zhao, Ming; Wang, Jin

2018-02-01

The aim of this study was to optimize the extraction process of polysaccharides from the fruiting bodies of Lentinus edodes and investigate its anti-hepatitis B virus activity. The extracting parameters including ultrasonic power (240-320W), extraction temperature (40-60°C) and extraction time (15-25min) was optimized by using three-variable-three-level Box-Behnken design based on the single-factor experiments. Data analysis results showed that the optimal conditions for extracting LEPs were an extraction temperature of 45°C, extraction time of 21min and ultrasonic power of 290W. Under these optimal conditions, the experimental yield of LEPs was 9.75%, a 1.62-fold increase compared with conventional heat water extraction (HWE). In addition, crude polysaccharides were purified to obtain two fractions (LEP-1 and LEP-2). Chemical analysis showed that these components were rich in glucose, arabinose and mannose. Furthermore, HepG2.2.15 cells were used as in vitro models to evaluate their anti-hepatitis B virus (HBV) activity. The results suggest that LEPs possesses potent anti-HBV activity in vitro. Copyright © 2017 Elsevier B.V. All rights reserved.

Isolation and characterization of two novel ethanol-tolerant facultative-anaerobic thermophilic bacteria strains from waste compost.

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Fong, Jiunn C N; Svenson, Charles J; Nakasugi, Kenlee; Leong, Caine T C; Bowman, John P; Chen, Betty; Glenn, Dianne R; Neilan, Brett A; Rogers, Peter L

2006-10-01

In a search for potential ethanologens, waste compost was screened for ethanol-tolerant thermophilic microorganisms. Two thermophilic bacterial strains, M5EXG and M10EXG, with tolerance of 5 and 10% (v/v) ethanol, respectively, were isolated. Both isolates are facultative anaerobic, non-spore forming, non-motile, catalase-positive, oxidase-negative, Gram-negative rods that are capable of utilizing a range of carbon sources including arabinose, galactose, mannose, glucose and xylose and produce low amounts of ethanol, acetate and lactate. Growth of both isolates was observed in fully defined minimal media within the temperature range 50-80 degrees C and pH 6.0-8.0. Phylogenetic analysis of the 16S rDNA sequences revealed that both isolates clustered with members of subgroup 5 of the genus Bacillus. G+C contents and DNA-DNA relatedness of M5EXG and M10EXG revealed that they are strains belonging to Geobacillus thermoglucosidasius. However, physiological and biochemical differences were evident when isolates M5EXG and M10EXG were compared with G. thermoglucosidasius type strain (DSM 2542(T)). The new thermophilic, ethanol-tolerant strains of G. thermoglucosidasius may be candidates for ethanol production at elevated temperatures.

Chemical properties and antioxidant activity of a water-soluble polysaccharide from Dendrobium officinale.

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Luo, Qiu-Lian; Tang, Zhuan-Hui; Zhang, Xue-Feng; Zhong, Yong-Hong; Yao, Su-Zhi; Wang, Li-Sheng; Lin, Cui-Wu; Luo, Xuan

2016-08-01

In this report, a water-soluble polysaccharide was obtained from the dried stems of Dendrobium officinale Kimura et Migo by hot-water (70-75°C) extraction and 85% ethanol precipitation, and successively purification by DEAE-cellulose anion-exchange chromatography and gel-permeation chromatography. The D. officinale polysaccharide (DOP) has a molecular weight of 8500Da. Monosaccharide composition analysis reveals that DOP is composed of mannose, glucose, and arabinose with a trace of galacturonic acid in a molar ratio of 6.2:2.3:2.1:0.1. Periodate oxidation-smith degradation and 1D and 2D NMR spectroscopy analysis suggest the predominance of mannose and glucose, and it contains a 2-O-acetylglucomannan and (1→4)-linked-β-d-mannopyranosyl and (1→4)-linked-β-d-glucopyranosyl residues. Atomic force microscope shows that DOP mainly exists as rod-shaped chains, supporting high degrees of polymerization. The antioxidant activities of the polysaccharide in vitro assay indicate that DOP has good scavenging activity of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, higher scavenging activity of hydroxyl radical, and metal chelating activities. Copyright © 2016 Elsevier B.V. All rights reserved.

Monosaccharide composition of acidic gum exudates from Indian Acacia tortilis ssp. raddiana (Savi) Brenan.

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Lakhera, Ajeet Kumar; Kumar, Vineet

2017-01-01

Acacia tortilis ssp. raddiana (Savi) Brenan commonly known as Israeli Babool has contributed immensely for sand dunes management in Indian desert leading to wind erosion control and increased biological productivity. The species is extensively used in traditional medicine system for a number of therapeutic applications and as nutraceutical. The polysaccharide was isolated in 43.6% yield from gum exudates. The monosaccharides, L-arabinose, D-galactose D-glucose, L-rhamnose and D-mannose were determined in molar ratio of 78.1%, 18.64%, 0.60%, 1.71% and 0.74% respectively. The molar ratio of uronic acids was studied using diverse spectrophotometric methods and compared with GLC. The content of D-galacturonic acid and D-glucuronic was determined as 3.88% and 4.35% respectively by GLC. The results were compared with the spectrophotometric methods. The results using DMP as chromogenic reagent are closer to that obtained by GLC. Structural analysis of the polysaccharide may provide scientific basis for nutraceutical, pharmaceutical and biological applications of gum exudates from A. tortilis, which is extensively planted in India. Copyright © 2016 Elsevier B.V. All rights reserved.

Polymyxin susceptibility testing, interpretative breakpoints and resistance mechanisms: An update.

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Bakthavatchalam, Yamuna Devi; Pragasam, Agila Kumari; Biswas, Indranil; Veeraraghavan, Balaji

2018-03-01

Emerging multidrug-resistant (MDR) nosocomial pathogens are a great threat. Polymyxins, an old class of cationic polypeptide antibiotic, are considered as last-resort drugs in treating infections caused by MDR Gram-negative bacteria. Increased use of polymyxins in treating critically ill patients necessitates routine polymyxin susceptibility testing. However, susceptibility testing both of colistin and polymyxin B (PMB) is challenging. In this review, currently available susceptibility testing methods are briefly discussed. The multicomponent composition of colistin and PMB significantly influences susceptibility testing. In addition, poor diffusion in the agar medium, adsorption to microtitre plates and the synergistic effect of the surfactant polysorbate 80 with polymyxins have a great impact on the performance of susceptibility testing methods This review also describes recently identified chromosomal resistance mechanisms, including modification of lipopolysaccharide (LPS) with 4-amino-4-deoxy-l-arabinose (L-Ara4-N) and phosphoethanolamine (pEtN) resulting in alteration of the negative charge, as well as the plasmid-mediated colistin resistance determinants mcr-1, mcr-1.2, mcr-2 and mcr-3. Copyright © 2017 International Society for Chemotherapy of Infection and Cancer. Published by Elsevier Ltd. All rights reserved.

Modificações dos componentes de parede celular do melão tipo Galia durante a maturação Cell wall components changes in 'Galia' melons during maturation

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Josivan B. MENEZES

1997-12-01

Full Text Available O presente estudo caracterizou quantitativa e qualitativamente as mudanças nos componentes de parede celular do melão tipo Galia, híbrido Nun 1380, associadas ao processo de maturação. Os frutos foram avaliados em cinco estádios de maturação (I-V. O material de parede celular e suas frações foram determinados por gravimetria. Determinou-se o conteúdo de açúcares neutros na fração hemicelulósica e no resíduo celulósico, o teor de ácidos urônicos e o grau de esterificação na fração de substâncias pécticas, e o teor de cálcio total e ligado. A fração de substâncias pécticas foi submetida à cromatografia de filtração em gel e os açúcares neutros da fração hemicelulósica foram analisados por cromatografia a gás. O conteúdo do material de parede celular (MPC mostrou pouca variação durante a maturação. O conteúdo de ácidos urônicos da fração péctica e o conteúdo de açúcares neutros na fração hemicelulósica (ramnose, arabinose e glicose apresentaram tendência de redução com o avanço da maturação do fruto. Praticamente não houve variação para o grau de esterificação (% de esterificação da fração de substâncias pécticas e para o teor de cálcio ligado. Houve redução no teor de celulose durante a maturação. A cromatografia em gel não revelou tendência de despolimerização das substâncias pécticas.This research characterized changes in the cell wall components in ‘Galia’, hybrid Nun 1380 melons during maturation. Fruits were evaluated at five maturation stages (I-V. Cell wall material and their fractions were determined by gravimetry method. Neutral sugars in hemicellulosic fraction and cellulosic residue, uronics acids content in pectic fraction, degree of esterification, total calcium and bound calcium were analyzed. The pectic fraction was analyzed by gel chromatography and neutral-sugars in hemicellulosic fraction were analyzed by gas chromatography. Minimum variation

Caracterização de bactérias dos gêneros Mima e Herella (Tribo Mimeae, DeBord, 1942: 1 Propriedade morfo-bioquímicas e sensibilidade aos antibióticos

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Altair A. Zebral

1971-01-01

Full Text Available No presente trabalho, os autores estudaram as propriedades morfo-bioquímicas e a sinsibilidade aos antibióticos de 19 amostras de bactérias dos gêneros Mima e Herellea isoladas de material clínico e identificadas como Mima polymorpha variedade oxidans, Mima polymorpha e Herellea vaginicola. No estudo bioquímico observou-se que Herellea vaginicola foi oxidase negativa e em meio complexo nitrogenado, consistentemente ataca a glicose, galactose, manose, arabinose, xilose, lactose a 10% e irregularmente ataca a ramnose e a celobiose; em base sintética nitrogenada, além das atividades citadas, consistentemente produziu ácido a partir da lactose. Mima polymopha foi oxidase negativa, não apresentando atividade glicidolítica, quer em meio complexo nitrogenado, quer em base sintética nitrogenada. Mima polymorpha var. oxidans, foi oxidase positiva, não revelando nenhuma atividade glicidolítica. Herellea vaginicola e Mima polymorpha mostraram grande sensibilidade à gabromicina, knamicina, neomicina, colistin, sendo que a última também foi muito sensível ao cloranfenicol e rovamicina. Mima polymorpha var. oxidans, apresentou grande sensibilidade à knamicina, neomicina, colistin, cloranfenicol e wintomylon. A sensibilidade das amostras a 1 a 0,1 unidade de penicilina/ml, nas condições ensaiadas no presente trabalho, não foi absoluta, como a observada por Baumann, Doudoroff & Stanier (1968a que permitisse uma separação entre amostras oxidase positiva e negativa ou uma diferenciação dentro do grupo das bactérias oxidase positiva.The authors studied the morpho-biochemical characteristics and antibiotic sensitivity of 19 strains of bacteria isolated from clinical specimens and identifyed as Mima polymorpha var. oxidans, Mima polymorpha and Herellea vaginicola. The biochemical study indicated Herellea vaginicola to be oxidase negative and in complex nitrogenous media effetively utilize glucose, galactose, manose, arabinose, xylose, 10

Cold induced changes on sugar contents and respiratory enzyme activities in coffee genotypes Alterações dos teores de açúcares e da atividade de enzimas do metabolismo respiratório em genótipos de café submetidos ao frio

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Fábio Luiz Partelli

2010-04-01

Full Text Available The present research aimed to characterize some biochemical responses of Coffea canephora (clones 02 and 153 and C. arabica (Catucaí IPR 102 genotypes subjected to low positive temperatures, helping to elucidate the mechanisms involved in cold tolerance. For that, one year old plants were subjected successively to 1 a temperature decrease (0.5°C a day from 25/20°C to 13/8°C (acclimation period, 2 a three day chilling cycle (3x13/4°C and to 3 a recovery period of 14 days (25/20°C. In Catucaí (less cold sensitive when compared to clone 02 there was an increased activity in the respiratory enzymes malate dehydrogenase and pyruvate kinase. Furthermore, Catucaí showed significant increases along the cold imposition and the higher absolute values after chilling exposure of the soluble sugars (sucrose, glucose, fructose, raffinose, arabinose and mannitol that are frequently involved in osmoregulation and membrane stabilization/protection. The analysis of respiratory enzymes and of soluble sugar balance may give valuable information about the cold acclimation/tolerance mechanisms, contributing to a correct selection and breeding of Coffea sp. genotypes.A pesquisa teve por objetivo caracterizar respostas bioquímicas de genótipos de Coffea canephora (clones 02 and 153 e C. arabica (Catucaí IPR 102 submetidos a baixas temperaturas positivas, ajudando a elucidar os mecanismos envolvidos na tolerância ao frio. Plantas com um ano de idade foram submetidas sucessivamente a 1 decréscimo da temperatura (0,5°C por dia desde 25/20°C até 13/8°C (período de aclimatização, 2 um ciclo de três dias a 13/4°C e 3 14 dias de recuperação (25/20°C. Em Catucaí, genótipo menos sensível ao frio quando comparado com o clone 02, observou-se um aumento das atividades das enzimas malato desidrogenase e piruvate cinase, relacionadas com a respiração. Nesse genótipo, os níveis de açúcares solúveis sacarose, glucose, frutose, rafinose, arabinose e

Caracterização do material de reserva em feijão-guandu, lablabe e mucuna Characterization of the storage material in guandu, lab-lab and mucuna

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Maria Silvia Seno

1996-01-01

Full Text Available Com o intuito de caracterizar, em nível citoquímico, as principais reservas presentes em guandu, lablabe e mucuna, sementes foram fixadas e processadas para a microscopia, utilizando-se tanto métodos gerais como específicos para proteínas, lipídios, polissacarídeos neutros e ácidos, procedendo-se, à dosagem e à caracterização dessas reservas nas sementes. O amido revelou-se como principal material, seguido por proteínas e, em menor grau, por lipídios. O conteúdo de amido foi de 55% da matéria seca (MS para guandu, 53% para lablabe e 40% para mucuna. As proteínas foram mais abundantes em lablabe, com 26% da MS, seguindo-se o guandu (19% e a mucuna (17%. Lipídios representaram menos de 2% da MS dessas sementes, com uma quantidade maior em mucuna do que nas demais espécies. As análises dos açúcares neutros presentes indicaram grande conteúdo de glicose em função do amido e quantidade apreciável de galactose e arabinose, sempre em maior quantidade em mucuna. Os perfis eletroforéticos revelaram semelhança maior entre as proteínas de guandu e lablabe, sugerindo maior proximidade filogenética entre tais espécies. As proteínas mais abundantes apresentaram massa molecular relativa entre 65 e 70 kg/mol.For the cytochemical characterization of the storage material present in guandu, lab-lab and mucuna, seeds of each species were fixed and prepared for microscopy. Routine and specific fixation methods for proteins, lipids, neutral and acidic polysaccharides were used. The main reserves of the seeds were also analyzed and characterized. The results showed that starch is the principal reserve, with proteins surrounding the starch grains, as well as a few lipid globules. The starch concentration was 55% of the dry weight (DW for guandu, 53% for lab-lab and 40% for mucuna. The proteins were more abundant in lab-lab, with 26% DW, while guandu and mucuna had respectively 19% and 17%. Lipids represented up to 2% of the total DW of

Polissacarídeos extraídos da gabiroba (Campomanesia xanthocarpa Berg: propriedades químicas e perfil reológico Polysaccharide isolated from gabiroba (Campomanesia xanthocarpa Berg: chemical properties and rheology profile

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Marli da S. Santos

2010-01-01

Full Text Available A Campomanesia xanthocarpa Berg (Myrtaceae é uma frutífera nativa brasileira, com ampla distribuição natural na região Sul. Embora apresente frutificação abundante, produza frutos com características sensoriais e nutricionais atrativas, esses não são coletados e se perdem nos campos. Neste trabalho, a polpa do fruto sem semente (1500 g foi triturada em etanol / água na proporção de 1:4 (v/v, refluxada por 15 minutos em temperatura de ebulição. O resíduo obtido foi submetido a extrações sequenciais. As extrações foram otimizadas utilizando um planejamento fatorial 2², tendo como variáveis a concentração do ácido cítrico (0,5 e 5% e a temperatura (50 e 100 ºC. Os polissacarídeos provenientes de diferentes extrações foram caracterizados quanto à composição química e perfil reológico. Os altos teores de ácidos urônicos, arabinose e galactose detectados em todas as frações, indicam que estas são constituídas por polissacarídeos pécticos. Os polissacarídeos extraídos da polpa da gabiroba apresentaram um comportamento pseudoplástico. Todas as frações apresentaram como característica resistência frente às variações de temperatura. Quando submetidas a ciclos de aquecimento e posterior resfriamento estes géis retornam à sua estrutura original.The Campomanesia xanthocarpa Berg (Myrtaceae is a Brazilian native fruit, widely abundant in the Southern region. Despite their large fructification, in addition to nutritional and attractive sensory characteristics, these fruits are not collected, being lost in the fields. In this work, the fruit pulp without seed (1500 g was crushed in ethanol/water at a ratio of 1:4 (v/v, refluxed for 15 minutes at boiling temperature. The residue obtained was subjected to sequential extractions. The extractions were optimized using a factorial design 2², with the concentration of citric acid (0.5 and 5% and temperature (50 and 100 ºC as variables. The polysaccharides were

Enzymatic extraction of pectin from artichoke (Cynara scolymus L.) by-products using Celluclast®1.5L.

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Sabater, Carlos; Corzo, Nieves; Olano, Agustín; Montilla, Antonia

2018-06-15

The aim of this study was to optimise pectin extraction from artichoke by-products with Celluclast ® 1.5L using an experimental design analysed by response-surface methodology (RSM). The variables optimised were artichoke by-product powder concentration (2-7%, X 1 ), enzyme dose (2.2-13.3 U g -1 , X 2 ) and extraction time (6-24 h, X 3 ). The variables studied were galacturonic acid (GalA) (R 2 93.9) and pectic neutral sugars (R 2 92.8) content and pectin yield (R 2 88.6). In the optimum extraction conditions (X 1  = 6.5%; X 2  = 10.1 U g -1 ; X 3  = 27.2 h), pectin yield was 176 mgg -1 dry matter (DM). Considering 27.2 h of treatment as the +α value given by the design, the extraction time was increased up to 48 h obtaining a yield of 221 mg g -1 DM. The enzymatic method optimised allows obtaining artichoke pectin with good yield, high GalA (720 mg g -1 DM) and arabinose (127.6mgg -1 DM) contents and degree of methylation of 19.5%. Copyright © 2018 Elsevier Ltd. All rights reserved.

Polysaccharide rich fractions from barks of Ximenia americana inhibit peripheral inflammatory nociception in mice Antinociceptive effect of Ximenia americana polysaccharide rich fractions

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Kaira E.S. da Silva-Leite

Full Text Available Abstract Ximenia americana L., Olacaceae, barks are utilized in folk medicine as analgesic and anti-inflammatory. The objective was to evaluate the toxicity and antinociceptive effect of polysaccharides rich fractions from X. americana barks. The fractions were obtained by extraction with NaOH, followed by precipitation with ethanol and fractionation by ion exchange chromatography. They were administered i.v. or p.o. before nociception tests (writhing, formalin, carragenan-induced hypernociception, hot plate, or during 14 days for toxicity assay. The total polysaccharides fraction (TPL-Xa: 8.1% yield presented 43% carbohydrate (21% uronic acid and resulted in two main fractions after chromatography (FI: 12%, FII: 22% yield. FII showed better homogeneity/purity, content of 44% carbohydrate, including 39% uronic acid, arabinose and galactose as major monosaccharides, and infrared spectra with peaks in carbohydrate range for COO- groups of uronic acid. TPL-Xa (10 mg/kg and FII (0.1 and 1 mg/kg presented inhibitory effect in behavior tests that evaluate nociception induced by chemical and mechanical, but not thermal stimuli. TPL-Xa did not alter parameters of systemic toxicity. In conclusion, polysaccharides rich fractions of X. americana barks inhibit peripheral inflammatory nociception, being well tolerated by animals.

Evaluation of Carbohydrates in Natural and Cultured Cordyceps by Pressurized Liquid Extraction and Gas Chromatography Coupled with Mass Spectrometry

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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.

Chemical Composition and Antioxidant Activities of Three Polysaccharide Fractions from Pine Cones

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Pu Wang

2012-11-01

Full Text Available The traditional method of gas chromatography-mass spectrometry for monosaccharide component analysis with pretreatment of acetylation is described with slight modifications and verified in detail in this paper. It was then successfully applied to the quantitative analysis of component monosaccharides in polysaccharides extracted from the pine cones. The results demonstrated that the three pine cone polysaccharides all consisted of ribose, rhamnose, arabinose, xylose, mannose, glucose and galactose in different molar ratios. According to the recovery experiment, the described method was proved accurate and practical for the analysis of pine cone polysaccharides, meeting the need in the field of chemical analysis of Pinus plants. Furthermore; the chemical characteristics, such as neutral sugar, uronic acids, amino acids, molecular weights, and antioxidant activities of the polysaccharides were investigated by chemical and instrumental methods. The results showed that the chemical compositions of the polysaccharides differed from each other, especially in the content of neutral sugar and uronic acid. In the antioxidant assays, the polysaccharide fractions exhibited effective scavenging activities on ABTS radical and hydroxyl radical, with their antioxidant capabilities decreasing in the order of PKP > PAP > PSP. Therefore, although the polysaccharide fractions had little effect on superoxide radical scavenging, they still have potential to be developed as natural antioxidant agents in functional foods or medicine.

Partial characterization of soluble polysaccharides leaves Malva parviflora L. (Malvaceae): prebiotic activity

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Boual, Z.; Kemassi, A.; Oudjana, A.H.; Michaud, P.; Didi, O.H.M.

2013-01-01

Malva parviflora L. (Malvaceae), a spontaneous plant used in traditional medicine is found inGhardaia (Septentrional EastAlgerian Sahara). This paper reports on the extraction and partial characterization of water-soluble polysaccharides from M. parviflorleaves. These polysaccharides were obtained by elimination of the ethanol extract and sequential extraction in distilled water, followed by precipitation in 75% ethanol. The yield of extract is of 1.46%. The crude water soluble polysaccharide extract was further characterized and revealed the average values:15 ± 2,64% total ashes, 17,14 ± 1,43% proteins and 68,18 ± 0,94% carbohydrates, among them 44,96 ± 0,42% are acidic monosaccharides and the rest 55 ± 0,62% are neutral monosaccharides. The considered optimum conditions of hydrolysis by trifluoroacetic acid were: 4 M during 5 hours at 80°C. Anion exchange high performance chromatography of hydrosoluble polysaccharides of Malva leaves indicates the presence of galactose (56.86%), glucuronic acid (20.57%), arabinose (9.04%), rhamnose (8.46%) and mannose (5.05%). The oligosaccharides resulting from the partial hydrolys is of the hydrosoluble polysaccharides stimulate significantly (concentration of 0,333 mg/mL) for 0,1 DO after 24 hours, the growth of Bifido bacterium longum. Their prebiotic effect is notable. (author)

FERMENTABLE SUGARS FROM Lupinus rotundiflorus BIOMASS BY HYDROCHLORIC ACID HYDROLYSIS

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Mario A. Ruiz-López

2011-02-01

Full Text Available It is of general interest to produce fermentable carbohydrates from plant biomass. However, obtaining monosaccharides requires some effort, due to the intricate structure of the cell wall lignocellulosic complex. The aim of this study was to apply a simple two-stage hydrolysis process, using only concentrated hydrochloric acid, to generate fermentable carbohydrates from L. rotundiflorus biomass. First and second stage acid concentrations were 32% and 42.6%. Total monosaccharide yields with respect to dry matter after the first stage, second stage, and the overall process, were 27.5%, 21.0% and 48.4%, respectively. Xylose was the main first stage carbohydrate in the hydrolysate, followed by glucose, arabinose, and galactose. After the second stage only glucose and a small amount of xylose were detected. The polysaccharide hydrolysis was eased by overall low lignin content. Some advantages of this method were the use of a single hydrolyzing agent and that most of the polysaccharides were hydrolyzed in reasonably high yields. The acceptable yield, relative simplicity, the use of most of the biomass along with the wide availability, low cost of the chemicals, and the ample supply of lupines, would facilitate the scaling of these laboratory studies to pilot and industrial levels.

Optimization of Alkaline Extraction and Bioactivities of Polysaccharides from Rhizome of Polygonatum odoratum

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Chen, Yong; Yin, Luoyi; Zhang, Xuejiao; Wang, Yan; Chen, Qiuzhi; Jin, Chenzhong; Wang, Jihua

2014-01-01

The present study is to explore the optimal extraction parameters, antioxidant activity, and antimicrobial activity of alkaline soluble polysaccharides from rhizome of Polygonatum odoratum. The optimal extraction parameters were determined as the following: NaOH concentration (A) 0.3 M, temperature (B) 80°C, ratio of NaOH to solid (C) 10-fold, and extraction time (D) 4 h, in which ratio of NaOH to solid was a key factor. The order of the factors was ratio of NaOH to solid (fold, C) > extraction temperature (°C, B) > NaOH concentration (M, A) > extraction time (h, D). The monosaccharide compositions of polysaccharides from P. odoratum were rhamnose, mannose, xylose, and arabinose with the molecular ratio of 31.78, 31.89, 11.11, and 1.00, respectively. The reducing power, the 1, 1-diphenyl-2-picryl-hydrazil (DPPH) radical scavenging rate, the hydroxyl radicals scavenging rate, and the inhibition rate to polyunsaturated fatty acid (PUFA) peroxidation of the alkaline soluble polysaccharides from P. odoratum at 1 mg/mL were 9.81%, 52.84%, 19.22%, and 19.42% of ascorbic acid at the same concentration, respectively. They also showed antimicrobial activity against pathogenic bacteria Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus subtilis, and Escherichia coli. PMID:25093173

Extraction Optimization, Characterization, and Bioactivities of Polysaccharides from Pinelliae Rhizoma Praeparatum Cum Alumine Employing Ultrasound-Assisted Extraction.

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Liu, Yu-Jie; Mo, Xue-Lin; Tang, Xiao-Zhang; Li, Jiang-Hua; Hu, Mei-Bian; Yan, Dan; Peng, Wei; Wu, Chun-Jie

2017-06-09

In this study, the ultrasound-assisted extraction of polysaccharides (PSA) from Pinelliae Rhizoma Praeparatum Cum Alumine (PRPCA) was optimized by response surface methodology (RSM). The structural characteristics of PSA were analyzed by UV-vis spectroscopy, infrared spectroscopy, scanning electron microscopy, high performance gel permeation chromatography and high performance liquid chromatography, respectively. In addition, antioxidant and antimicrobial activities of PSA were studied by different in vitro assays. Results indicated that the optimal extraction conditions were as follows: the ratio of water to raw of 30 mL/g, extraction time of 46.50 min, ultrasonic temperature of 72.00 °C, and ultrasonic power of 230 W. Under these conditions, the obtained PSA yield (13.21 ± 0.37%) was closely agreed with the predicted yield by the model. The average molecular weights of the PSA were estimated to be 5.34 × 10³ and 6.27 × 10⁵ Da. Monosaccharide composition analysis indicated that PSA consisted of mannose, galactose uronic acid, glucose, galactose, arabinose with a molar ratio of 1.83:0.55:75.75:1.94:0.45. Furthermore, PSA exhibited moderate antioxidant and antibacterial activities in vitro. Collectively, this study provides a promising strategy to obtain bioactive polysaccharides from processed products of herbal medicines.

Preliminary Characterization, Antioxidant and Hepatoprotective Activities of Polysaccharides from Taishan Pinus massoniana Pollen

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Changming Zhou

2018-01-01

Full Text Available The objectives of the present study were to characterize the chemical composition, antioxidant activity and hepatoprotective effect of the polysaccharides from Taishan Pinus massoniana pollen (TPPPS. HPLC analysis showed that TPPPS was an acidic heteropolysaccharide with glucose and arabinose as the main component monosaccharides (79.6%, molar percentage. Fourier transform-infrared spectroscopy (FT-IR analysis indicated that the spectra of TPPPS displayed infrared absorption peaks characteristic of polysaccharides. In in vitro assays TPPPS exhibited different degrees of dose-dependent antioxidant activities , and this was further verified by suppression of CCl4-induced oxidative stress in the liver with three tested doses of TPPPS (100, 200, and 400 mg/kg bw in rats. Pretreatment with TPPPS significantly decreased the levels of alanine aminotransferase (AST, aspartate aminotransferase (ALT, alkaline phosphatase (ALP, lactic dehydrogenase (LDH and malondialdehyde (MDA against CCl4 injuries, and elevated the activities of superoxide dismutase (SOD as well as glutathione peroxidase (GSH-Px. Histopathological observation further confirmed that TPPPS could protect the liver tissues from CCl4-induced histological alternation. These results suggest that TPPPS has strong antioxidant activities and significant protective effect against acute hepatotoxicity induced by CCl4. The hepatoprotective effect may partly be related to its free radical scavenging effect, increasing antioxidant activity and inhibiting lipid peroxidation.

Comparative Phenotype and Genome Analysis of Cellvibrio sp. PR1, a Xylanolytic and Agarolytic Bacterium from the Pearl River

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Zhangzhang Xie

2017-01-01

Full Text Available Cellvibrio sp. PR1 is a xylanolytic and agarolytic bacterium isolated from the Pearl River. Strain PR1 is closely related to Cellvibrio fibrivorans and C. ostraviensis (identity > 98%. The xylanase and agarase contents of strain PR1 reach up to 15.4 and 25.9 U/mL, respectively. The major cellular fatty acids consisted of C16:0 (36.7%, C18:0 (8.8%, C20:0 (6.8%, C15:0 iso 2-OH or/and C16:1ω7c (17.4%, and C18:1ω7c or/and C18:1ω6c (6.7%. A total of 251 CAZyme modules (63 CBMs, 20 CEs, 128 GHs, 38 GTs, and 2 PLs were identified from 3,730 predicted proteins. Genomic analysis suggested that strain PR1 has a complete xylan-hydrolyzing (5 β-xylanases, 16 β-xylosidases, 17 α-arabinofuranosidases, 9 acetyl xylan esterases, 4 α-glucuronidases, and 2 ferulic acid esterases and agar-hydrolyzing enzyme system (2 β-agarases and 2 α-neoagarooligosaccharide hydrolases. In addition, the main metabolic pathways of xylose, arabinose, and galactose are established in the genome-wide analysis. This study shows that strain PR1 contains a large number of glycoside hydrolases.

Nutritional Profile and Carbohydrate Characterization of Spray-Dried Lentil, Pea and Chickpea Ingredients

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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.

The production of arabitol by a novel plant yeast isolate Candida parapsilosis 27RL-4

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Kordowska-Wiater Monika

2017-10-01

Full Text Available Polyalcohol arabitol can be used in the food and pharmaceutical industries as a natural sweetener, a dental caries reducer, and texturing agent. Environmental samples were screened to isolate effective yeast producers of arabitol. The most promising isolate 27RL-4, obtained from raspberry leaves, was identified genetically and biochemically as Candida parapsilosis. It secreted 10.42– 10.72 g l-1 of product from 20 g l-1 of L-arabinose with a yield of 0.51 - 0.53 g g-1 at 28°C and a rotational speed of 150 rpm. Batch cultures showed that optimal pH value for arabitol production was 5.5. High yields and productivities of arabitol were obtained during incubation of the yeast at 200 rpm, or at 32°C, but the concentrations of the polyol did not exceed 10 g l-1. In modified medium, with reduced amounts of nitrogen compounds and pH 5.5-6.5, lower yeast biomass produced a similar concentration of arabitol, suggesting higher efficiency of yeast cells. This strain also produced arabitol from glucose, with much lower yields. The search for new strains able to successfully produce arabitol is important for allowing the utilization of sugars abundant in plant biomass.

ISOLATION AND CHARACTERIZATION OF A MOLYBDENUM-REDUCING AND GLYPHOSATE-DEGRADING Klebsiella oxytoca STRAIN SAW-5 IN SOILS FROM SARAWAK

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M.K. Sabullah

2016-02-01

Full Text Available Bioremediation of pollutants including heavy metals and xenobiotics is an economic and environmentally friendly process. A novel molybdenum-reducing bacterium with the ability to utilize the pesticide glyphosate as a carbon source is reported. The characterization works were carried out utilizing bacterial resting cells in a microplate format. The bacterium reduces molybdate to Mo-blue optimally between pH 6.3 and 6.8 and at 34oC. Glucose was the best electron donor for supporting molybdate reduction followed by lactose, maltose, melibiose, raffinose, d-mannitol, d-xylose, l-rhamnose, l-arabinose, dulcitol, myo-inositol and glycerol in descending order. Other requirements include a phosphate concentration at 5.0 mM and a molybdate concentration between 20 and 30 mM. The molybdenum blue exhibited an absorption spectrum resembling a reduced phosphomolybdate. Molybdenum reduction was inhibited by mercury, silver, cadmium and copper at 2 ppm by 45.5, 26.0, 18.5 and 16.3%, respectively. Biochemical analysis identified the bacterium as Klebsiella oxytoca strain Saw-5. To conclude, the capacity of this bacterium to reduce molybdenum into a less toxic form and to grow on glyphosate is novel and makes the bacterium an important instrument for bioremediation of these pollutants.

Physical, chemical, and metabolic state sensors expand the synthetic biology toolbox for Synechocystis sp. PCC 6803.

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Immethun, Cheryl M; DeLorenzo, Drew M; Focht, Caroline M; Gupta, Dinesh; Johnson, Charles B; Moon, Tae Seok

2017-07-01

Many under-developed organisms possess important traits that can boost the effectiveness and sustainability of microbial biotechnology. Photoautotrophic cyanobacteria can utilize the energy captured from light to fix carbon dioxide for their metabolic needs while living in environments not suited for growing crops. Various value-added compounds have been produced by cyanobacteria in the laboratory; yet, the products' titers and yields are often not industrially relevant and lag behind what have been accomplished in heterotrophic microbes. Genetic tools for biological process control are needed to take advantage of cyanobacteria's beneficial qualities, as tool development also lags behind what has been created in common heterotrophic hosts. To address this problem, we developed a suite of sensors that regulate transcription in the model cyanobacterium Synechocystis sp. PCC 6803 in response to metabolically relevant signals, including light and the cell's nitrogen status, and a family of sensors that respond to the inexpensive chemical, l-arabinose. Increasing the number of available tools enables more complex and precise control of gene expression. Expanding the synthetic biology toolbox for this cyanobacterium also improves our ability to utilize this important under-developed organism in biotechnology. Biotechnol. Bioeng. 2017;114: 1561-1569. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Tamarind Seed Xyloglucans Promote Proliferation and Migration of Human Skin Cells through Internalization via Stimulation of Proproliferative Signal Transduction Pathways

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W. Nie

2013-01-01

Full Text Available 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.

Rhodococcus antrifimi sp. nov., isolated from dried bat dung of a cave.

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Ko, Kwan Su; Kim, Youngju; Seong, Chi Nam; Lee, Soon Dong

2015-11-01

A Gram-reaction-positive, high DNA G+C content, non-motile actinobacterium, strain D7-21T, was isolated from dried bat dung inside a natural cave and its taxonomic status was examined by using a polyphasic approach. The 16S rRNA gene sequence study showed that the isolate belonged to the genus Rhodococcus and formed a cluster with Rhodococcus defluvii (98.98 % gene similarity), Rhodococcus equi (98.62 %) and Rhodococcus kunmingensis (97.66 %). Whole-cell hydrolysates contained meso-diaminopimelic acid, arabinose and galactose as the diagnostic diamino acid and sugars. MK-8(H2) was the predominant menaquinone. The major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol, phosphatidylinositol mannoside, an unknown phosphoglycolipid and an unknown glycolipid. Mycolic acids were present. The major fatty acids were C16 : 0, C18 : 1ω9c and 10-methyl C18 : 0. The DNA G+C content was 70.1 mol%. A battery of phenotypic features and DNA-DNA relatedness data support that strain D7-21T ( = KCTC 29469T = DSM 46727T) represents a novel species of the genus Rhodococcus, for which Rhodococcus antrifimi sp. nov. is proposed.

Biochemical traits useful for the determination of genetic variation in a natural population of Myracrodruon urundeuva

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Abdala Ludmila

2002-01-01

Full Text Available The objectives of this work were to analyze seeds from 20 trees of aroeira (Myracrodruon urundeuva Fr. All. of a natural population located in the region of Selvíria, State of Mato Grosso do Sul, Brazil, in order to evaluate their protein, lipid and carbohydrate contents, and to estimate their genetic variation. A completely randomized experimental design consisting of 20 treatments (families was set up, with two replications. Four types of proteins were detected: albumin (35.0 to 107.3 mg/g seed, globulin (3.4 to 9.3 mg/g, prolamin (60.0 to 135.2 mg/g and glutelin (118.0 to 286.0 mg/g. The lipid content varied between 200 and 334 mg/g seed. The total sugars also varied (26.5 to 46.3 mg/g seed, with a predominance of polyols (arabinitol, mannitol, glucitol and xylitol. The main monosaccharides detected were glucose and arabinose. Total hydrolysis of the sugars indicated the presence of neutral arabinan and xylan oligosaccharides. The starch content varied from 0.35 to 1.58 mg/g seed. These biochemical traits showed considerable genetic variability, indicating that only the collection of seeds from many different trees can provide a representative sample of the population for conservation and genetic improvement.

Enzymatic saccharification and fermentation of paper and pulp industry effluent for biohydrogen production

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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)

Characterization of soluble dietary fiber from Moringa oleifera seeds and its immunomodulatory effects.

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Anudeep, Sandanamudi; Prasanna, Vaddi K; Adya, Shruthi M; Radha, Cheruppanpullil

2016-10-01

Moringa oleifera (moringa or drumstick) seeds are a potential source of dietary fiber with 6.5% w/w soluble dietary fiber. Biochemical characterization of moringa seed soluble fiber revealed that it is a glycoprotein with 5% neutral sugars. Arabinose and xylose are the major neutral sugars identified by gas liquid chromatography (GLC). Moringa seed soluble fiber was identified as protease resistant-glycoprotein and termed as moringa seed resistant protein (MSRP). MSRP was found to be a homodimer (18kDa) containing two 9kDa monomeric units as revealed by SDS-PAGE analysis with pI 10.8. Immunostimulating activity of MSRP was assessed by murine splenocyte proliferation and production of NO from macrophages. MSRP at low concentration (0.01μg/well) strongly increased proliferation of splenocytes, while MSRP at high concentration weakly responded. MSRP induced 6-fold increase in NO production when compared to the control which indicates the activation of macrophages. MSRP isolated from defatted moringa seed flour is a potent mitogen, enhancing the proliferation of lymphocytes and inducing NO from macrophages. This study concludes that moringa seed is a potential nutritional source to promote the immune system of the host. Copyright © 2016 Elsevier B.V. All rights reserved.

Phosphate stresses affect ionome and metabolome in tea plants.

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Ding, Zhaotang; Jia, Sisi; Wang, Yu; Xiao, Jun; Zhang, Yinfei

2017-11-01

In order to study the response of tea plants to P stress, we conducted the ionomic and metabolomic analysis by ICP-OES, GC-MS and LC-MS. The results demonstrated that P was antagonistic with S, and was cooperative with Cu, Zn, Mn and Fe under P-deficiency. However, P was antagonistic with Mn, Fe and S, and was cooperative with Cu and Zn under P-excess. Moreover, P-deficiency or excess reduced the syntheses of flavonoids and phosphorylated metabolites. P-deficiency decreased the amount of glutamate and increased the content of glutamine, while P-excess decreased the content of glutamine. Besides, P-deficiency increased three organic acids and decreased three organic acids. P-excess increased the contents of malic acid, oxalic acid, ribonic acid and etc. involved in primary metabolism, but decreased the contents of p-coumaric acid, indoleacrylic acid, related to secondary metabolism. Furthermore, the contents of Mn and Zn were found to be positively related to the amounts of myricetin and quercetin, and the content of Mn to be positively related to the amount of arabinose. The results implied that the P stresses severely disturbed the metabolism of minerals and metabolites in tea plants, which influenced the yield and quality of tea. Copyright © 2017. Published by Elsevier Masson SAS.

A Study on the Interaction of Rhodamine B with Methylthioadenosine Phosphorylase Protein Sourced from an Antarctic Soil Metagenomic Library

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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. PMID:23383268

Changes in Cell Wall Polysaccharides Associated With Growth 1

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Nevins, Donald J.; English, Patricia D.; Albersheim, Peter

1968-01-01

Changes in the polysaccharide composition of Phaseolus vulgaris, P. aureus, and Zea mays cell walls were studied during the first 28 days of seedling development using a gas chromatographic method for the analysis of neutral sugars. Acid hydrolysis of cell wall material from young tissues liberates rhamnose, fucose, arabinose, xylose, mannose, galactose, and glucose which collectively can account for as much as 70% of the dry weight of the wall. Mature walls in fully expanded tissues of these same plants contain less of these constituents (10%-20% of dry wt). Gross differences are observed between developmental patterns of the cell wall in the various parts of a seedling, such as root, stem, and leaf. The general patterns of wall polysaccharide composition change, however, are similar for analogous organs among the varieties of a species. Small but significant differences in the rates of change in sugar composition were detected between varieties of the same species which exhibited different growth patterns. The cell walls of species which are further removed phylogenetically exhibit even more dissimilar developmental patterns. The results demonstrate the dynamic nature of the cell wall during growth as well as the quantitative and qualitative exactness with which the biosynthesis of plant cell walls is regulated. PMID:16656862

Structure and biological activities of a pectic polysaccharide from Mosla chinensis Maxim. cv. Jiangxiangru.

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Li, Jing-En; Cui, Steve W; Nie, Shao-Ping; Xie, Ming-Yong

2014-05-25

A water-soluble pectic polysaccharide (MP-A40) was isolated and purified from Mosla chinensis Maxim. cv. Jiangxiangru for the first time, with a molecular weight of 32,600Da. MP-A40 was comprised of 68.63% galacturonic acid and 13.05% neutral sugar. In addition, arabinose, galactose, rhamnose, mannose and glucose composed the neutral sugar in a relative ratio of 4.94, 3.07, 2.13, 1.62 and 1.29% of the dry weight of MP-A40, respectively. Structural characterization of MP-A40 was investigated by methylation analysis and 1D/2D NMR spectroscopy. From the results, the structure of MP-A40 was revealed as follows: 1,4-linked α-d-GalpA and 1,4-linked α-d-GalpA6Me interspersed with rare t-Araf (0.60%), t-Rhap (1.67%) and t-GalpA (10.15%). Esterification assay showed that about 32% of the carboxylic groups in GalA residues existed as methyl ester. In addition, MP-A40 could inhibit the growth of human leukemic cell line K562 and stimulate nitric oxide production from RAW 264.7 macrophages both in dose-dependent manners. Copyright © 2014 Elsevier Ltd. All rights reserved.

Characteristics of a pink-pigmented bacterium isolated from biofilm in a cooling tower in Tokyo, Japan.

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Furuhata, Katsunori; Goto, Keiichi; Kato, Yuko; Saitou, Keiko; Sugiyama, Jun-ichi; Hara, Motonobu; Yoshida, Shin-ichi; Fukuyama, Masafumi

2007-01-01

Strain K-20, a Gram-negative, non-motile, non-spore-forming and strictly aerobic rod, which produces a pale pink pigment, was isolated from biofilm in a cooling tower in Tokyo, Japan. The taxonomic feature of the strain was studied using phenotypic tests and phylogenetic analysis. Phylogenetic analysis of 16S rRNA gene sequences showed that the strain was related to Roseomonas gilardii subsp. rosea, Roseomonas gilardii subsp. gilardii, Roseomonas cervicalis and Roseomonas mucosa at 94.3-94.6 sequence similarities. Growth occurred at 25-40 C and pH 5.0-10.0, optimal at 35 C and pH 7.0. Growth did not occur in the presence of >or=2% NaCl. The API 20NE identification system gave a positive result for urease, L-arabinose, potassium gluconate, adipic acid, malic acid and trisodium citrate (API code number 0201465). The predominant fatty acids of strain K-20 were C18:1Delta11 (50.8%) and C16:1 (17.2%). Cells contained ubiquinone 10 (Q-10) as the major quinone and the G+C content was 72.0 mol%. Based on phenotypic, chemotaxonomic and phylogenetic data, it was assumed that strain K-20 (=JCM 14634) is a novel species of the genus Roseomonas.

Conversion of acid hydrolysate of oil palm empty fruit bunch to L-lactic acid by newly isolated Bacillus coagulans JI12.

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Ye, Lidan; Hudari, Mohammad Sufian Bin; Zhou, Xingding; Zhang, Dongxu; Li, Zhi; Wu, Jin Chuan

2013-06-01

Cost-effective conversion of lignocellulose hydrolysate to optically pure lactic acid is commercially attractive but very challenging. Bacillus coagulans JI12 was isolated from natural environment and used to produce L-lactic acid (optical purity > 99.5 %) from lignocellulose sugars and acid hydrolysate of oil palm empty fruit bunch (EFB) at 50 °C and pH 6.0 without sterilization of the medium. In fed-batch fermentation with 85 g/L initial xylose and 55 g/L xylose added after 7.5 h, 137.5 g/L lactic acid was produced with a yield of 98 % and a productivity of 4.4 g/L h. In batch fermentation of a sugar mixture containing 8.5 % xylose, 1 % glucose, and 1 % L-arabinose, the lactic acid yield and productivity reached 98 % and 4.8 g/L h, respectively. When EFB hydrolysate was used, 59.2 g/L of lactic acid was produced within 9.5 h at a yield of 97 % and a productivity of 6.2 g/L h, which are the highest among those ever reported from lignocellulose hydrolysates. These results indicate that B. coagulans JI12 is a promising strain for industrial production of L-lactic acid from lignocellulose hydrolysate.

Determination of Single Sugars, Including Inulin, in Plants and Feed Materials by High-Performance Liquid Chromatography and Refraction Index Detection

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Kirsten Weiß

2017-08-01

Full Text Available The exact and reliable detection of sugar monomers and fructans provides important information for the evaluation of carbohydrate metabolism in plants and animals. Using the HPLC method; a large number of samples and single sugars; with both high sensitivity and selectivity; may be analysed. It was shown that the described method—using a Nucleosil column loaded with Pb2+ ions; a refractive index detector (RID; and HPLC-grade water as the eluent—gives precise and reproducible results regarding the detection of individual sugars in extracts of plants and feed materials. The method can be applied for the detection of sucrose; maltose; lactose; xylose; glucose; galactose; arabinose; fructose; ribose; and mannitol. Furthermore; depending on the plant material; the sugars verbascose; stachyose; and raffinose can be separated. The peaks were well resolved and the reproducibility of the analysis; with 94–108% of recovery (RC and relative standard deviation (RSD of up to 5%; was very good. The method was successfully applied to a variety of green forages and samples of sugar beet pulp silages. It is also possible to determine fructan with inulin as a standard; together with the other sugars; or alone by a different protocol and column.

Fifteenth symposium on biotechnology for fuels and chemicals: Program and abstracts

Energy Technology Data Exchange (ETDEWEB)

1993-07-01

This collection contains 173 abstracts from presented papers and poster sessions. The five sessions of the conference were on the subjects of: (1) Thermal, Chemical, and Biological Processing, (2) Applied Biological Research, (3) Bioprocessing Research (4), Process Economics and Commercialization, and (5) Environmental Biotechnology. Examples of specific topics in the first session include the kinetics of ripening cheese, microbial liquefaction of lignite, and wheat as a feedstock for fuel ethanol. Typical topics in the second session were synergism studies of bacterial and fungal celluloses, conversion of inulin from jerusalem artichokes to sorbitol and ethanol by saccharomyces cerevisiae, and microbial conversion of high rank coals to methane. The third session entertained topics such as hydrodynamic modeling of a liquid fluidized bed bioreactor for coal biosolubilization, aqueous biphasic systems for biological particle partitioning, and arabinose utilization by xylose-fermenting yeast and fungi. The fourth session included such topics as silage processing of forage biomass to alcohol fuels, economics of molasses to ethanol in India, and production of lactic acid from renewable resources. the final session contained papers on such subjects as bioluminescent detection of contaminants in soils, characterization of petroleum contaminated soils in coral atolls in the south Pacific, and landfill management for methane generation and emission control.

Dietary fiber content influences soluble carbohydrate levels in ruminal fluids.

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Pinder, R S; Patterson, J A; O'Bryan, C A; Crandall, P G; Ricke, S C

2012-01-01

The soluble carbohydrate concentration of ruminal fluid, as affected by dietary forage content (DFC) and/or ruminally undegradable intake protein content (UIPC), was determined. Four ruminally cannulated steers, in a 4 × 4 Latin square design, were offered diets containing high (75 % of DM) or low (25 % of DM) DFC and high (6 % of DM) or low (5 % of DM) UIPC, in a 2 × 2 factorial arrangement. Zinc-treated SBM was the primary UIP source. Soluble hexose concentration (145.1 μM) in ruminal fluid (RF) of steers fed low DFC diets exhibited a higher trend (P = 0.08) than that (124.5 μM) of steers fed high DFC diets. UIPC did not modulate (P = 0.54) ruminal soluble hexose concentrations. Regardless of diet, soluble hexose concentration declined immediately after feeding and did not rise until 3 h after feeding (P ruminal fluid could not be determined. However, unsubstituted xylose and arabinose were excluded. These data indicate that: (i) soluble carbohydrate concentrations remain in ruminal fluid during digestion and fermentation; (ii) slight diurnal changes began after feeding; (iii) DFC influences the soluble carbohydrate concentration in RF; and (iv) UIPC of these diets does not affect the soluble carbohydrate concentration of RF.

Degradation of seed mucilage by soil microflora promotes early seedling growth of a desert sand dune plant.

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Yang, Xuejun; Baskin, Carol C; Baskin, Jerry M; Zhang, Wenhao; Huang, Zhenying

2012-05-01

In contrast to the extensive understanding of seed mucilage biosynthesis, much less is known about how mucilage is biodegraded and what role it plays in the soil where seeds germinate. We studied seed mucilage biodegradation by a natural microbial community. High-performance anion-exchange chromatography (HPAEC) was used to determine monosaccharide composition in achene mucilage of Artemisia sphaerocephala. Mucilage degradation by the soil microbial community from natural habitats was examined by monosaccharide utilization tests using Biolog plates, chemical assays and phospholipid fatty acid (PLFA) analysis. Glucose (29.4%), mannose (20.3%) and arabinose (19.5%) were found to be the main components of achene mucilage. The mucilage was biodegraded to CO(2) and soluble sugars, and an increase in soil microbial biomass was observed during biodegradation. Fluorescence microscopy showed the presence of mucilage (or its derivatives) in seedling tissues after growth with fluorescein isothiocyanate (FITC)-labelled mucilage. The biodegradation also promoted early seedling growth in barren sand dunes, which was associated with a large soil microbial community that supplies substances promoting seedling establishment. We conclude that biodegradation of seed mucilage can play an ecologically important role in the life cycles of plants especially in harsh desert environments to which A. sphaerocephala is well-adapted. © 2011 Blackwell Publishing Ltd.

Phenotypic variation in Lactococcus lactis subsp. lactis isolates derived from intestinal tracts of marine and freshwater fish.

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Itoi, S; Yuasa, K; Washio, S; Abe, T; Ikuno, E; Sugita, H

2009-09-01

We compared phenotypic characteristics of Lactococcus lactis subsp. lactis derived from different sources including the intestinal tract of marine fish and freshwater fish, and cheese starter culture. In the phylogenetic analysis based on partial 16S rRNA gene nucleotide sequences (1371 bp), freshwater fish-, marine fish- and cheese starter culture-derived strains were identical to that of L. lactis subsp. lactis previously reported. Fermentation profiles determined using the API 50 CH system were similar except for fermentation of several sugars including l-arabinose, mannitol, amygdalin, saccharose, trehalose, inulin and gluconate. The strains did have distinct levels of halotolerance: marine fish-derived strains > cheese starter-derived strain > freshwater fish-derived isolate. Lactococcus lactis subsp. lactis showed extensive diversity in phenotypic adaptation to various environments. The phenotypic properties of these strains suggested that L. lactis subsp. lactis strains from fish intestine have additional functions compared with the cheese starter-derived strain that has previously described. The unique phenotypic traits of the fish intestinal tract-derived L. lactis subsp. lactis might make them useful as a probiotics in aquaculture, and contribute to the development of functional foods and novel food additives, since the strains derived from fish intestines might have additional functions such as antibacterial activity.

Single and combined effects of acetic acid, furfural, and sugars on the growth of the pentose-fermenting yeast Meyerozyma guilliermondii.

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Perna, Michelle Dos Santos Cordeiro; Bastos, Reinaldo Gaspar; Ceccato-Antonini, Sandra Regina

2018-02-01

The tolerance of the pentose-fermenting yeast Meyerozyma guilliermondii to the inhibitors released after the biomass hydrolysis, such as acetic acid and furfural, was surveyed. We first verified the effects of acetic acid and cell concentrations and initial pH on the growth of a M. guilliermondii strain in a semi-synthetic medium containing acetic acid as the sole carbon source. Second, the single and combined effects of furfural, acetic acid, and sugars (xylose, arabinose, and glucose) on the sugar uptake, cell growth, and ethanol production were also analysed. Growth inhibition occurred in concentrations higher than 10.5 g l -1 acetic acid and initial pH 3.5. The maximum specific growth rate (µ) was 0.023 h -1 and the saturation constant (ks) was 0.75 g l -1 acetic acid. Initial cell concentration also influenced µ. Acetic acid (initial concentration 5 g l -1 ) was co-consumed with sugars even in the presence of 20 mg l -1 furfural without inhibition to the yeast growth. The yeast grew and fermented sugars in a sugar-based medium with acetic acid and furfural in concentrations much higher than those usually found in hemicellulosic hydrolysates.

Lignin development tests. Announcement I. Characteristics of celluloselignin derived in production of furfural

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Rozmarin, Ch.; Popa, V.I.

1982-01-01

During production of furfural from waste agricultural plants, a large quantity of cellulose-lignin is left (CL). Provides analysis results on tests carried out to determine potential chemical application of this complex product. In particular, it was shown that in corncobs and in sunflower seed husks, the following components are present, respectively (%): difficult to hydrolize polysaccharides 42.8 and 20.3, easily hydrolized 38.2 and 27.9; lignin 20.3 and 26.55; acids: galacturonic 7 and 5.5, glycuronic 9 and 7; monosaccharides: galactose 7 and 5.5, glycose - traces and 7, arabinose 10.8 and 8.4, xylose 45 and 40, ramnose 9 and 9. CL derived during production of furfural, contains (%): ash 6.47, difficult to hydrolize polysaccharides 37.25, residual lignin after hydrolysis with 80% H/sub 2/SO/sub 4/ 57.5, PB in cold water extract 9.05, -OCH/sub 3/ 5.02, -OH 33.1, acids extracted with cold water, 5.32. Composition of lignin extracted with cold water from CL (%): C-60.58, H-5.03, 0-34.39, ash 0.58, -OCH/sub 3/, 5.51, OH 13.96. The given date make it possible to conclude that CL has a complex composition which must be taken in account when selecting its utilization.

Extraction Optimization, Preliminary Characterization and Bioactivities in Vitro of Ligularia hodgsonii Polysaccharides

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Xueping Song

2016-05-01

Full Text Available The optimization extraction, preliminary characterization and bioactivities of Ligularia hodgsonii polysaccharides were investigated. Based on single-factor experiments and orthogonal array test, the optimum extraction conditions were obtained as follows: extraction time 3 h, temperature 85 °C, water/raw material ratio 36. Further Sevag deproteinization and dialysis yielded the dialyzed Ligularia hodgsonii polysaccharides (DLHP, 19.2 ± 1.4 mg/g crude herb. Compositional analysis, size-exclusion chromatography connected with multi-angle laser light-scattering and refractive index (SEC-MALLS-RI, Fourier transform infrared (FT-IR and 1H nuclear magnetic resonance (NMR spectroscopy were employed for characterization of the polysaccharides. DLHP was found to have a major component with a weight-average molecular weight of 1.17 × 105 Da, mainly comprising of glucose, galactose, arabinose, mannose, rhamnose, glucuronic acid and galacturonic acid. By in vitro antioxidant activity assays, DLHP presented remarkable scavenging capacities towards 1,1-diphenyl-2-picrylhydrazyl (DPPH, 2,2′-azinobis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS and hydroxyl radicals, and ferrous ions chelating ability. Moreover, it exhibited appreciable anti-hyperglycemic activity as demonstrated by differential inhibition of α-glucosidase and α-amylase. The results indicated that DLHP could potentially be a resource for antioxidant and hypoglycemic agents.

Size-fractionated dissolved primary production and carbohydrate composition of the coccolithophore Emiliania huxleyi

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Borchard, C.; Engel, A.

2015-02-01

Extracellular release (ER) by phytoplankton is the major source of fresh dissolved organic carbon (DOC) in marine ecosystems and accompanies primary production during all growth phases. Little is known, so far, on size and composition of released molecules, and to which extent ER occurs passively, by leakage, or actively, by exudation. Here, we report on ER by the widespread and bloom-forming coccolithophore Emiliania huxleyi grown under steady-state conditions in phosphorus-controlled chemostats (N:P = 29, growth rate of μ = 0.2 d-1) at present-day and high-CO2 concentrations. 14C incubations were performed to determine primary production (PP), comprised of particulate (PO14C) and dissolved organic carbon (DO14C). Concentration and composition of particulate combined carbohydrates (pCCHO) and high-molecular-weight (>1 kDa, HMW) dissolved combined carbohydrates (dCCHO) were determined by ion chromatography. Information on size distribution of ER products was obtained by investigating distinct size classes (10 kDa was significantly different, with a higher mol% of arabinose. The mol% of acidic sugars increased and that of glucose decreased with increasing size of HMW-dCCHO. We conclude that larger polysaccharides follow different production and release pathways than smaller molecules, potentially serving distinct ecological and biogeochemical functions.

Structural characterization of polysaccharides from Cabernet Franc, Cabernet Sauvignon and Sauvignon Blanc wines: Anti-inflammatory activity in LPS stimulated RAW 264.7 cells.

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Bezerra, Iglesias de Lacerda; Caillot, Adriana Rute Cordeiro; Palhares, Lais Cristina Gusmão Ferreira; Santana-Filho, Arquimedes Paixão; Chavante, Suely Ferreira; Sassaki, Guilherme Lanzi

2018-04-15

The structural characterization of the polysaccharides and in vitro anti-inflammatory properties of Cabernet Franc (WCF), Cabernet Sauvignon (WCS) and Sauvignon Blanc (WSB) wines were studied for the first time in this work. The polysaccharides of wines gave rise to three fractions of polysaccharides, namely (WCF) 0.16%, (WCS) 0.05% and (WSB) 0.02%; the highest one was chosen for isolation of polysaccharides (WCF). It was identified the presence of mannan, formed by a sequence of α-d-Manp (1 → 6)-linked and side chains O-2 substituted for α-d-mannan (1 → 2)-linked; type II arabinogalactan, formed by (1 → 3)-linked β-d-Galp main chain, substituted at O-6 by (1 → 6)-linked β-d-Galp side chains, and nonreducing end-units of arabinose 3-O-substituted; type I rhamnogalacturonan formed by repeating (1 → 4)-α-d-GalpA-(1 → 2)-α-L-Rhap groups; and traces of type II rhamnogalacturonan. The polysaccharide mixture and isolated fractions inhibited the production of inflammatory cytokines (TNF-α and IL-1β) and mediator (NO) in RAW 264.7 cells stimulated with LPS. Copyright © 2018 Elsevier Ltd. All rights reserved.