Efficient xylose utilisation by microorganisms is of importance to the lignocellulose fermentation industry. The aim of this work was to develop constitutive catabolite repression mutants in a xylose-utilising recombinant Saccharomyces cerevisiae strain and evaluate the differences in xylose consumption under fermentation conditions. S. cerevisiae YUSM was constitutively catabolite repressed through specific disruptions within the MIG1 gene. The strains were grown aerobically in synthetic complete medium with xylose as the sole carbon source. Constitutive catabolite repressed strain YCR17 grew four-fold better on xylose in aerobic conditions than the control strain YUSM. Anaerobic batch fermentation in minimal medium with glucose-xylose mixtures and N-limited chemostats with varying sugar concentrations were performed. Sugar utilisation and metabolite production during fermentation were monitored. YCR17 exhibited a faster xylose consumption rate than YUSM under high glucose conditions in ...
Glycoside hydrolases (O-Glycosyl hydrolases) EC 3.2.1. are a widespread group of enzymes that hydrolyse the glycosidic bond between two or more carbohydrates, or between a carbohydrate and a non-carbohydrate moiety. A classification system for glycosyl hydrolases, based on sequence similarity, has led to the definition of numerous different families. This classification is available on the CAZy (CArbohydrate-Active EnZymes) web site. Because the fold of proteins is better conserved than their sequences, some of the families can be grouped in clans. As of October 2011, CAZy includes 128 families of glycosyl hydrolases and 14 clans. Glycoside hydrolase family 1 Glycoside hydrolase family 2 Glycoside hydrolase family 3 Glycoside hydrolase family 4 Glycoside hydrolase family 5 Glycoside hydrolase family 6 Glycoside hydrolase family 7 Glycoside hydrolase family 8 Glycoside hydrolase family 9 Glycoside hydrolase family 10 Glycoside hydrolase family 11 Glycoside hydrolase family 12 Glycoside ...
Cell wall hemicelluloses and pectins are O-acetylated at specific positions, but the significance of these substitutions is poorly understood. Using a transgenic approach, we investigated how reducing the extent of O-acetylation in xylan affects cell wall chemistry, plant performance and the recalcitrance of lignocellulose to saccharification. The Aspergillus niger acetyl xylan esterase AnAXE1 was expressed in Arabidopsis under the control of either the constitutively expressed 35S CAMV promoter or a woody-tissue-specific GT43B aspen promoter, and the protein was targeted to the apoplast by its native signal peptide, resulting in elevated acetyl esterase activity in soluble and wall-bound protein extracts and reduced xylan acetylation. No significant alterations in cell wall composition were observed in the transgenic lines, but their xylans were more easily digested by a beta-1,4-endoxylanase, and more readily extracted by hot water, acids or alkali. Enzymatic saccharification of lignocellulose ...
A genomic DNA library of the bacterium Bacillus pumilus PLS was constructed and the beta-xylosidase gene (xynB) was amplified from a 3-kb genomic DNA fragment with the aid of the polymerase chain reaction technique. The amplified xynB gene was inserted between the yeast alcohol dehydrogenase II gene promoter (ADH2P) and terminator (ADH2T) sequences on a multicopy episomal plasmid (pDLG11). The xynB gene was also fused in-frame to the secretion signal sequence of the yeast mating pheromone a-factor (MFa1S) before insertion between the ADH2P and ADH2T sequences on a similar multicopy episomal plasmid (pDLG12). The resulting construct ADH2P-MFa1SxynB-ADH2T was designated XLO1. Both plasmids pDLG11 and pDLG12 were introduced into Saccharomyces cerevisiae but only the expression of the XLO1 gene yielded biologically functional beta-xylosidase. The total beta-xylosidase activity remained cell-associated with a maximum activity of 0.09 nkat/ml obtained when the recombinant S. cerevisiae strain was ...
Autoimmune Addisons disease (AAD) is a debilitating condition and affected patients rely on lifelong steroid replacement. Despite treatment, many patients have increased morbidity and mortality. The diseases rarity has precluded large scale genomic or cellular studies in humans, resulting in an incomplete picture of the pathophysiology of AAD. This thesis details my research on the pathophysiology and novel therapeutic approaches in AAD. I performed two candidate gene studies on susceptibility alleles that have been implicated in other autoimmune diseases to explore potential causal pathways of these genetic determinants in AAD. The common variant 307*Ser allele of CD226 gene was found to contribute to AAD susceptibility as part of autoimmune polyendocrinopathy type 2. Two genetic variants from a panel of rare and functionally defective variants in the sialic acid acetylesterase (SIAE) gene were identified but they were not significantly associated with AAD. I explored new therapeutic ...
In this work, we rewired the xylose isomerase assimilation and mitochondrial isobutanol production pathways in the budding yeast Saccharomyces cerevisiae. We then increased the flux through these pathways by making gene deletions of BAT1, ALD6, and PHO13, to develop a strain (YZy197) that produces as much as 4 g/L of BCHAs (3.10 ± 0.18 g isobutanol/L and 0.91 ± 0.02 g 2-methyl-1-butanol/L) from xylose. This represents approximately a 28-fold improvement on the highest isobutanol titers obtained from xylose previously reported in yeast and the first report of 2-methyl-1-butanol produced from xylose. The yield of total BCHAs is 57.2 ± 5.2 mg/g xylose, corresponding to ~ 14% of the maximum theoretical yield. Respirometry experiments show that xylose increases mitochondrial activity by as much as 7.3-fold compared to glucose. ...
Xylan, a major component of plant hemicellulose, is a complex, highly branched heteropolymer. Endo-β-1,4-xylanases (EC 3.2.1.8) are glycosidases that cleave the internal β-1,4-xylosidic bonds of the main chain of xylan and produce unbranched or branched xylooligosaccharides (1). Due to the complexity of the xylan structure, endo-β-1,4-xylanases are diverse in sequences, structures, hydrolytic activities, and enzymatic properties. They are distributed in glycoside hydrolase (GH) families 5, 7, 8, 10, 11, and 43. Among endo-β-1,4-xylanases, those from GH family 10 (GH10) and GH11 have been studied in more detail. GH10 xylanases have an (α/β)8 barrel structure (2), while GH11 xylanases have a β-jelly roll structure (3). Despite their different structures, both enzyme families adopt the catalytic mechanism of anomeric retention to release xylooligosaccharides from xylan (2, 3).. The endo-β-1,4-xylanases in GH family 8 reported so far include XylY from Bacillus sp. strain KK-1 (4), PhXyl from ...
In this paper, the improvement of a fed-batch fermentation from the point of view of an industrial xylanase production process is described. The Bacillus strain chosen for this study is able to produce high quantities of a xylanase that is suitable to be used as bleach boost agent in chlorine-free bleaching sequences of paper pulp. It was found that xylo-oligosaccharides hydrolysis products from xylan by xylanase action were indispensable for induction of the enzyme synthesis, but that their presence in quantities of only 0.1g dm^-3 xylose equivalents led to catabolite repression. A substrate-limited fed-batch process, that is the most adapted, was furthermore improved with regard to nutrient requirement of the microorganism, especially the nitrogen source. A process with constant supply of a culture medium containing xylan, peptone and mineral nitrogen was able to produce 20240nkatcm^-3 with a productivity of 910nkatcm^-3 h^-1, which places the process among the best ever reported. ...
TY - JOUR. T1 - O-Acetylation of glucuronoxylan in Arabidopsis thaliana wild type and its change in xylan biosynthesis mutants. AU - Chong, S L. AU - Virkki, L. AU - Maaheimo, Hannu. AU - Juvonen, M. AU - Derba-Maceluch, M. AU - Koutaniemi, S. AU - Roach, M. AU - Sundberg, B. AU - Tuomainen, P. AU - Mellerowicz, E J. AU - Tenkanen, M. PY - 2014. Y1 - 2014. N2 - O-Acetylglucuronoxylans (AcGX) in Arabidopsis thaliana carry acetyl residues on the 2-O and/or 3-O positions of the xylopyranosyl (Xylp) units, but the distribution of different O-acetylated Xylp units is partly unclear. We studied a possible correlation of xylan acetylation and the activities of different glycosyltransferases involved in xylan biosynthesis by analyzing the distribution of O-acetyl substituents on AcGX from Arabidopsis wild-type and mutants irx7, irx9-1, irx10, irx14 and gux1gux2. The relative contents of the Xylp structural units were determined with quantitative two-dimensional heteronuclear single quantum coherence ...
A rapid growing and high xylanase producing fungus Aspergillus niger SA7, was isolated from starch waste. The best yield of xylanase was 2400 U/g on the solid-state starch waste with 65-70% of initial moisture content at 28℃ for 3 days. Crude enzyme preparation contained more components of cellulase. Addition wheat bran to medium could stimulated xylanase production. 21.6% reducing sugar was obtained by hydrolysis starch waste at 45℃ culture for 24 hours.
A genomic library of Pseudomonas fluorescens subsp. cellulosa DNA constructed in pUC18 and expressed in Escherichia coli was screened for recombinants expressing 4-methylumbelliferyl beta-D-glucoside hydrolysing activity (MUGase). A single MUGase-positive clone was isolated. The MUGase hydrolysed cellobiose, cellotriose, cellotetraose, cellopentaose and cellohexaose to glucose, by sequentially cleaving glucose residues from the non-reducing end of the cello-oligosaccharides. The Km values for cellobiose and cellohexaose hydrolysis were 1.2 mM and 28 microM respectively. The enzyme exhibited no activity against soluble or insoluble cellulose, xylan and xylobiose. Thus the MUGase is classified as a 1,4-beta-D-glucan glucohydrolase (EC 3.2.1.74) and is designated 1,4-beta-D-glucan glucohydrolase D (CELD). When expressed by E. coli, CELD was located in the cell-envelope fraction; a significant proportion of the native enzyme was also associated with the cell envelope when synthesized by its ...
TY - JOUR. T1 - Characteristics of Trichoderma reesei ß-xylosidase and its use in the hydrolysis of solubilized xylans. AU - Poutanen, Kaisa. AU - Puls, Jurgen. PY - 1988. Y1 - 1988. N2 - The β-xylosidase (EC 3.2.1.37) of Trichoderma reesei was purified and its characteristics and use in the hydrolysis of steamed birch xylan were studied. The enzyme was a glycoprotein with a molecular weight of 100000 as determined by SDS-gel electrophoresis and its isoelectric point was 4.7. The pH optimum was 4.0 and temperature optimum 60°C. β-Xylosidase was competitively inhibited by xylose and the inhibition constant was 2.3 mM. The purified enzyme also showed α-arabinofuranosidase activity.. AB - The β-xylosidase (EC 3.2.1.37) of Trichoderma reesei was purified and its characteristics and use in the hydrolysis of steamed birch xylan were studied. The enzyme was a glycoprotein with a molecular weight of 100000 as determined by SDS-gel electrophoresis and its isoelectric point was 4.7. The pH optimum ...
Streptomyces thermoviolaceus ChiS protein: similar to histidine kinases; a member of a two-component sensor-regulator system; isolated from Streptomyces thermoviolaceus; amino acid sequence in first source; GenBank AB016841
Hymenaea courbaril (courbaril and West Indian locust) is a tree common in the Caribbean, Central America, and South America. It is a hardwood that is used for furniture, flooring, and decoration. Its hard fruit pods have edible dry pulp surrounding the seeds. Its sap, called animé, is used for incense, perfume, and varnish. Hymenaea courbaril is commonly known as the "courbaril", "West Indian locust", "Brazilian copal", and "amami-gum". Although it is sometimes denominated "Brazilian cherry" and "South American cherry",[citation needed] it is not a cherry tree but a legume of the Fabaceae family. It is also known as "stinking toe", "old mans toe", and "stinktoe" because of the unpleasant odor of the edible pulp of its seed pods. Its fruit, also known as locust, was a major food for indigenous peoples. Those who eat it do not consider the odor unpleasant. The pulp, in spite of its somewhat disagreeable odor, has a sweet taste; is consumed raw; may be dried and transformed into powder to be ...
The influence of the auxotrophic deficiencies of the host strain and expression vector selection on the production of a heterologous protein was investigated. Heterologous xylanase production by two prototrophic S. cerevisiae transformants, containing either a plasmid-based, YEp-type expression system or an integrative, YIp-type expression system, were compared with production by an auxotrophic transformant, containing an identical YEp-type expression system, in batch and continuous cultivation, using a chemically defined medium. Heterologous xylanase production by the auxotrophic strains in defined medium was critically dependent on the availability of amino acids, as extracellular xylanase production increased dramatically when amino acids were over-consumed from the medium to the point of saturating the cell. Saturation with amino acids, indicated by an increased leakage of amino acids from the cell, was thus a prerequisite for high level of heterologous; protein production by the auxotrophic ...
TY - JOUR. T1 - Proliferation of retinal pigment epithelial cells induced by (R, R)-XY-10 and (S, S)-XY-10 and their action mechanisms. AU - Cheng, Yu Wen. AU - Wang, Yu Liang. AU - Zhang, Yi Hua. AU - Peng, Si Xun. AU - Chiou, George C.Y.. PY - 2009/10/22. Y1 - 2009/10/22. N2 - • AIM: To investigate the mechanism of proliferation effect induced by (R, R)-XY-10 and (S, S)-XY-10 on retinal pigmented epithelial cells (ARPE-19). • METHODS: Human retinal pigmented epithelial cells (ARPE-19) and human umbilical vein endothelial cells (HUVECs) were used to investigate the effect of (R, R)-XY-10 and (S, S)-XY-10 on cell growth, and their mechanisms of proliferative action by using ERKinverted commas AKTinverted commas PI3Kinverted commas Protein kinase C (PKC)and Nitric oxide synthase (NOS) inhibitors. RESULTS: (R, R)-XY-10 and (S, S)-XY-10 dose-dependently increased ARPE-19 cell proliferation, but not on HUVECs. When treated with proliferative inhibitors, H7 (5μ mol/L)inverted commas hypericin ...
Yeast Pichia stipitis CBS 5776 was developed through adaptation fermentation step by step in steam exploded corn stover prehydrolyzate because high concentration of weak acids and other inhibitors present in the prehydrolyzate could degrade the fermentability. However, the adaptability of Pichia stipitis CBS 5776 in the prehydrolyzate was so limited that steam strip-ping and overliming were applied to remove these inhibitors from it. Corn stover was steam exploded; the filtrate of steam exploded corn stover was hydrolyzed with dilute sulfuric acid, and then the acid hydrolyzate was detoxified and fermented by Pichia stipitis CBS 5776. Steam stripping could remove volatile com-pounds from the acid hydrolyzate and the fil-trate. At a steam stripping time of 120min, 81% acetic acid and 59% formic acid were removed from the acid hydrolyzate, 77% acetic acid and 45% formic acid were removed from the filtrate, while furfural was stripped off completely from the acid hydrolyzate and the filtrate. Overliming
The 20 kDa Bacillus circulans Bcx is a well-studied endoxylanase with a beta-jellyroll fold that places its N- and C-termini in salt bridge contact. initial experiments verified that Bcx could be circularly permuted. by PCR methods to introduce new termini in loop regions while linking its native termini directly or via one or two glycines. Subsequently, a library Of circular permutants, generated by random DNase cleavage of the circularized Bcx gene, was screened for xylarlase activity oil xylan in Congo Red-stained agar. Analysis of 35 unique active circular permutants revealed that, while many of the new termini were introduced in external loops as anticipated, a surprising number were also located within beta-strands. Furthermore, several permutations placed key catalytic residucs at or near the new termini with minimal delecterious effects Oil activity and, in one case, a 4-fold increase. The structure of one permutant Was determined by X-ray crystallography, whereas three others were ...
Direct utilization of untreated oil palm trunk (OPT) for cellulases and xylanase production by Aspergillus fumigatus SK1 was conducted under solid-state fermentation (SSF). The highest activities of extracellular cellulases and xylanases were produced at 80% moisture level, initial pH 5.0, 1 × 108 spore/g (inoculum) with 125 μm of OPT as sole carbon source. The cellulases and xylanase activities obtained were 54.27, 3.36, 4.54 and 418.70 U/g substrates for endoglucanase (CMCase), exoglucanase (FPase), β-glucosidase and xylanase respectively. The crude cellulases and xylanase required acidic condition to retain their optimum activities (pH 4.0). Crude cellulases and xylanase were more stable at 40°C compared to their optimum activities conditions (60°C for FPase and 70°C for CMCase, β-glucosidase and xylanase). SDS-PAGE and zymogram analysis showed that Aspergillus fumigatus SK1 could secrete cellulases (endoglucanase, exoglucanase and β-glucosidase), xylanase and protease. Enzymatic ...
A bacterial strain, designated PALXIL04T, was isolated from the phyllosphere of Phoenix dactylifera. Phylogenetic analysis placed the isolate within the genus Paenibacillus with the closest relatives being Paenibacillus curdlanolyticus and Paenibacillus kobensis. DNA-DNA hybridization measurements showed low DNA relatedness (15-20 %) between the isolate and its closest relatives. Cells were Gram-variable, facultatively anaerobic, motile, sporulating rods. Catalase and oxidase were produced by the organism. Cellulose, starch, aesculin and xylan were hydrolysed. Growth was supported by many carbohydrates as the carbon source. MK-7 was the predominant menaquinone and anteiso-C15 : 0 the major fatty acid. The G+C content of the DNA was 50·7 mol%. Phylogenetic, DNA-DNA relatedness and phenotypic analyses indicated that strain PALXIL04T represents a novel species of the genus Paenibacillus, for which the name Paenibacillus phyllosphaerae sp. nov. is proposed. The type strain is PALXIL04T (=LMG 22192T=CECT
TY - JOUR. T1 - Automated Yeast Transformation Protocol to Engineer Saccharomyces cerevisiae Strains for Cellulosic Ethanol Production with Open Reading Frames That Express Proteins Binding to Xylose Isomerase Identified Using a Robotic Two-Hybrid Screen. AU - Hughes, Stephen R.. AU - Rich, Joseph O.. AU - Bischoff, Kenneth M.. AU - Hector, Ronald E.. AU - Qureshi, Nasib. AU - Saha, Badal C.. AU - Dien, Bruce S.. AU - Liu, Siqing. AU - Jackson, John S.. AU - Sterner, David E.. AU - Butt, Tauseef R.. AU - LaBaer, Joshua. AU - Cotta, Michael A.. PY - 2009/8. Y1 - 2009/8. N2 - Commercialization of fuel ethanol production from lignocellulosic biomass has focused on engineering the glucose-fermenting industrial yeast Saccharomyces cerevisiae to use pentose sugars. Because S. cerevisiae naturally metabolizes xylulose, one approach involves introducing xylose isomerase (XI), which catalyzes conversion of xylose to xylulose. In this study, an automated two-hybrid interaction protocol was used to find ...
Pullulanase (EC 3.2.1.41, limit dextrinase, amylopectin 6-glucanohydrolase, bacterial debranching enzyme, debranching enzyme, alpha-dextrin endo-1,6-alpha-glucosidase, R-enzyme, pullulan alpha-1,6-glucanohydrolase) is a specific kind of glucanase, an amylolytic exoenzyme, that degrades pullulan. It is produced as an extracellular, cell surface-anchored lipoprotein by Gram-negative bacteria of the genus Klebsiella. Type I pullulanases specifically attack α-1,6 linkages, while type II pullulanases are also able to hydrolyse α-1,4 linkages. It is also produced by some other bacteria and archaea. Pullulanase is used as a processing aid in grain processing biotechnology (production of ethanol and sweeteners). Pullulanase is also known as pullulan-6-glucanohydrolase (Debranching enzyme). Its substrate, pullulan, is regarded as a chain of maltotriose units linked by alpha-1,6-glycosidic bonds. Pullulanase will hydrolytically cleave pullulan (alpha-glucan polysaccharides). Lee, E.Y.C.; Whelan, W.J. ...
Aims: To screen industrially important extracellular enzymes from the newly isolated alkalophilic bacilli and to characterize them by phenotypic and 16S-internal transcribed spacer (ITS) rDNA restriction pattern analysis. Methods and Results: Three different environmental samples, soil, leather and horse faeces, were collected within the province of Izmir. Isolates grown on Horikoshi-I medium for 24 h at 37°C were screened for extracellular enzyme activity by using eight different substrates: birchwood xylan, carboxymethylcellulose, casein, citrus pectin, polygalacturonic acid, soluble starch, and Tween 20 and 80. In total, 115 extracellular enzyme-producing bacilli were obtained. Casein was hydrolysed by 78%, soluble starch by 67%, citrus pectin by 63%, polygalacturonic acid by 62%, Tween 20 by 34%, birchwood xylan by 16%, Tween 80 by 12%, and carboxymethylcellulose by 3% of the isolates. The isolates were differentiated into 19 distinct homology groups by the 16S-ITS rDNA restriction pattern ...
The microbial degradation of the plant cell wall is a pivotal biological process that is of increasing industrial significance. One of the major plant structural polysaccharides is mannan, a beta-1,4-linked d-mannose polymer, which is hydrolyzed by endo- and exo-acting mannanases. The mechanisms by which the exo-acting enzymes target the chain ends of mannan and how galactose decorations influence activity are poorly understood. Here we report the crystal structure and biochemical properties of CjMan26C, a Cellvibrio japonicus GH26 mannanase. The exo-acting enzyme releases the disaccharide mannobiose from the nonreducing end of mannan and mannooligosaccharides, harnessing four mannose-binding subsites extending from -2 to +2. The structure of CjMan26C is very similar to that of the endo-acting C. japonicus mannanase CjMan26A. The exo-activity displayed by CjMan26C, however, reflects a subtle change in surface topography in which a four-residue extension of surface loop creates a steric block at ...
Barley limit dextrinase [Hordeum vulgare limit dextrinase (HvLD)] catalyzes the hydrolysis of α-1,6 glucosidic linkages in limit dextrins. This activity plays a role in starch degradation during germination and presumably in starch biosynthesis during grain filling. The crystal structures of HvLD in complex with the competitive inhibitors α-cyclodextrin (CD) and β-CD are solved and refined to 2.5 Å and 2.1 Å, respectively, and are the first structures of a limit dextrinase. HvLD belongs to glycoside hydrolase 13 family and is composed of four domains: an immunoglobulin-like N-terminal eight-stranded β-sandwich domain, a six-stranded β-sandwich domain belonging to the carbohydrate binding module 48 family, a catalytic (β/α)8-like barrel domain that lacks α-helix 5, and a C-terminal eight-stranded β-sandwich domain of unknown function. The CDs are bound at the active site occupying carbohydrate binding subsites + 1 and + 2. A glycerol and three water molecules mimic a glucose residue at ...
Cellulolytic enzymes capable of efficiently degrading crystalline cellulose are a complex mixture of endo- (endoglucanases) and exo-acting (cellobiohydrolases) enzymes. One approach to separating these enzymes is affinity chromatography. A new ligand, p-aminophenyl l-thio-β-D-cellobioside (APTC), is introduced for this purpose. The property of APTC in affinity chromatography is demonstrated using Trichoderma reesei cellulases. The behavior of these enzymes on APTC-affinity column was essentially equivalent to that reported for the same enzymes on p-aminobenzyl 1-thio-β- D-cellobioside (ABTC)-columns; ABTC being the traditional ligand for affinity chromatography of exocellulases. The primary advantage of the APTC ligand is its ease of preparation. The affinity between CBHs and APTC may be considerably affected by nonspecific interactions. In this study, the significance of nonspecific protein/matrix interactions in affinity chromatography of cellulolytic enzymes is evaluated. The role of pH, ...
Lactococcus lactis is being developed as a vaccine delivery system as it bears no threat to animal and human health. It has been used for centuries in the fermentation of foods and is generally recognised as safe. However, a safety factor pertaining to the type of selectable marker present on the vector system poses to be of concern. Chances of the transfer of antibiotic resistance genes, usually employed by vectors as selectable markers, into the natural environment become a possible risk. Therefore, there is a need for the development of ideal vectors without such selectable markers (Dertzbaugh, 1998). The activity of the xylanase gene of Bacillus coagulans ST -6 can be detected on Remazol Brilliant Blue-Xylan (RBB-Xylan) as a clear halo zone against a dark blue background. This characteristic allows xylanase to be used as a selectable chromogenic marker on any vector system. On the other hand, the matrix or membrane (M) protein of Newcastle disease virus (NDV) strain AF 2240 can be useful as ...
At SleepyDentistry.net youll find a reputable dental anesthesia and dental sedation provider that delivers safe and efficient relief to valued clients living in or near Larchwood, IA. Our licensed dentist anesthesiologist is well trained and equipped and specializes on pain control and patient management. From general anesthesia, tropical anesthesia, local anesthesia and other types of dental anesthesia, our certified and experienced anesthesiologist provide various anesthesia requirements for dental patients. We also offer portable in-office moderate dental sedation to provide a more comfortable dental experience. You may also want a moderate I.V. sedation instead for a more relaxed state during dental procedures especially for dental surgeries. If you have a post traumatic stress disorder, special medical conditions such as autism or mental illness, TMJ discomfort or suffer from anxiety, dental sedation is the best option. Our outstanding service is open to all 51241 patients as well as those ...
Binds to the N-acetyl-9-O-acetylneuraminic acid residues on the cell surface, bringing about the attachment of the virus particle to the cell. Plays a major role in the determination of host range restriction and virulence. Class I viral fusion protein. Responsible for penetration of the virus into the cell cytoplasm by mediating the fusion of the membrane of the endocytosed virus particle with the endosomal membrane. Low pH in endosomes induce an irreversible conformational change in HEF2, releasing the fusion hydrophobic peptide. Several trimers are required to form a competent fusion pore. Displays a receptor-destroying activity which is a neuraminidate-O-acetyl esterase. This activity cleaves off any receptor on the cell surface, which would otherwise prevent virions release. These cleavages prevent self-aggregation and ensure the efficient spread of the progeny virus from cell to cell (By similarity).
Post a Comment for Effects of beta-aminopropionitrile, L-azetidine-2-carboxylic acid and beta-xyloside on the tunica media of the developing chick aorta : a mongraphic study by Susan Averill Taylor. ...
Plant polysaccharides constitute arguably the most complex family of biomacromolecules in terms of the stereochemistry and regiochemistry of their intramolecular linkages. The chemical modification of such polysaccharides introduces an additional level of complexity for structural determinations. We have developed an integrated analytical procedure combining selective enzymatic hydrolysis, hydrophilic interaction liquid chromatography (HILIC), and mass spectrometry (MS) to describe the substitution pattern of xyloglucan (XyG) and its chemo-enzymatic derivatives (cationic, anionic, and benzyl aminated). Enzymatic hydrolysis of XyG derivatives by a xyloglucan-specific endoglucanase (XEG) generates oligosaccharides amenable for mass spectrometric identification with distinct structures, based on enzymatic substrate recognition and hydrolytic pattern. Matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-ToF-MS) and electrospray ionisation mass spectrometry (ESI-MS) ...
Article Biochemical Conversion of Acid-Pretreated Water Hyacinth (Eichhornia Crassipes) to Alcohol Using Pichia Stipitis NCIM3497. Cleaning and removal of water hyacinth from lakes and various historical places government spends lacks of rupees per y...
TY - JOUR. T1 - Myrosinases, TGG1 and TGG2, redundantly function in ABA and MeJA signaling in arabidopsis guard cells. AU - Islam, Mohammad Mahbub. AU - Tani, Chiharu. AU - Watanabe-Sugimoto, Megumi. AU - Uraji, Misugi. AU - Jahan, Md Sarwar. AU - Masuda, Choji. AU - Nakamura, Yoshimasa. AU - Mori, Izumi C.. AU - Murata, Yoshiyuki. PY - 2009/6/1. Y1 - 2009/6/1. N2 - Thioglucoside glucohydrolase (myrosinase), TGG1, is a strikingly abundant protein in Arabidopsis guard cells. We investigated responses of tgg1-3, tgg2-1 and tgg1-3 tgg2-1 mutants to abscisic acid (ABA) and methyl jasmonate (MeJA) to clarify whether two myrosinases, TGG1 and TGG2, function during stomatal closure. ABA, MeJA and H2O2 induced stomatal closure in wild type, tgg1-3 and tgg2-1, but failed to induce stomatal closure in tgg1-3 tgg2-1. All mutants and wild type showed Ca2-induced stomatal closure and ABA-induced reactive oxygen species (ROS)production. A model is discussed in which two myrosinases redundantly function ...
Lactobacillus pentosus TV35b, isolated from the posterior fornix secretions of the vagina of a prenatal patient, produced a bacteriocin-like peptide (pentocin TV35b), which is inhibitory to Clostridium sporogenes, Cl. tyrobutyricum, Lact. curvatus, Lact. fermentum, Lact. sake, Listeria innocua, Propionibacterium acidipropionici, Propionibacterium sp. and Candida albicans. The mechanism of activity of pentocin TV35b is bactericidal, as shown by a decrease in the viable cell numbers of Lact. sake from approximately 4 x 108 to less than 10 cfu ml-1 over a period of 4 h. Pentocin TV35b added to the growth medium of C. albicans stimulated the formation of pseudohyphae during the first 36 h, followed by a slight repression in cell growth. Production of pentocin TV35b was at its maximum towards the end of the logarithmic growth phase of strain TV35b. The peptide was purified by ammonium sulphate precipitation, followed by SP-Sepharose cation exchange chromatography. The molecular size of pentocin TV35b ...
Acta Crystallogr Sect F Struct Biol Cryst Commun. 2009 Apr 1;65(Pt 4):419-21. doi: 10.1107/S1744309109008719. Epub 2009 Mar 26. Research Support, Non-U.S. Govt
Clear differences in the number and nature of GH proteins secreted by S4F8 and Rut C30 were evident, with S4F8 expressing a larger range of GH families (32 versus 24 GH families in S4F8 and Rut C30, respectively), and more protein representatives per GH family (Figure 3). More proteins belonging to GH families 3 (β-glucosidase/β-xylosidase), 5 (various), 11 (endoxylanase), 16 (transglycosylase and glucanosyltransferase), 28 (polygalacturonase), 31 (α-glucosidase/α-xylosidase), 62 (α-L/N-arabinofuranosidase), 72 (glucanosyltransglycosylase) and 92 (mannosidase) were detected for S4F8. Representatives of GH families 10 (endoxylanase), 12 (endoglucanase), 15 (starch-related), 17 (glucan 1,3-β-glucosidase), 18 (chitinase), 43 (xylosidase), 47 (α-mannosidase), 79 (glucoronidase), 93 (exo-arabinase) and 95 (fucosidase) were unique to S4F8, whereas only representatives of GH families 30 (β-glucocerebrosidase) and 61 (endoglucanases, recently reclassified as copper-dependent lytic monooxygenases ...
A novel hemicellulase-producing fungal strain was isolated from a local soil sample. The organism is identified as Aspergillus fumigatus based on ribosomal RNA analyses. The Aspergillus strain, designated as 2NB, produces both enzymes acting on xylan backbone (xylanase and β-xylosidase), and those acting on side chains (or accessory enzymes) notably α-arabinofuranosidase and acetyl-xylan esterase. The Asperigillus hemicellulases are characterized as having relatively low xylanase and β-xylosidase activities but high side chain removal activities. The activity ratio of side-chain acting enzymes to xylanase is higher than that of the Multifect enzyme, a commercial hemicellulase product. The potential of the novel hemicellulases in lignocelluloses bioprocessing was demonstrated with alkaline-pretreated switchgrass as lignocellulose substrate with hemicellulase supplemented with a ratio of xylanase activity to filter paper unit of 2:1. Supplement of Aspergillus hemicellulases to commercial ...
The aim of this study was to gain a comprehensive understanding of how viable SAN progeny produces higher levels of xylanases [17]. We focused on candidate TFs exhibiting differential expression levels between SAN and euploid progeny (six TF-encoding genes: ID in jgi,Trire2: 106677, 65854, 111446, 68930, 111515, 36913), as well as another candidate TF, SxlR. We confirmed that SxlR is a negative regulator of GH11 family xylanases. However, overexpression of the other six tested TFs had no effect on the xylanase activity. It seems that the segmental aneuploidy did not result in a change in sxlr gene copy number; however, it is still unknown whether segmental aneuploidy affects the expression of sxlr in SAN progeny.. Recently, another negative regulator of hemi-cellulase, xylanase promoter-binding protein 1 (Xpp1) was reported in T. reesei [18]. Xpp1 regulates transcription of hemi-cellulase genes only at later stages of cultivation. There was no significant difference in xylanase activity between ...
GXM is composed of mannose, xylose, glucuronic acid, and O-acetyl residues. In our previous studies, we isolated two genes (CAS1 and UXS1) necessary for O-acetylation and xylosylation of the capsule, respectively (25, 30). Here, we constructed a strain lacking the UDP-glucose dehydrogenase. Although a salvage pathway exists in plants which are able to synthesize UDP-glucuronic acid via the oxidation of inositol to glucuronic acid and subsequent activation to the nucleotide sugar (35), phenotypic analysis of the udg1Δ strain suggests strongly that most if not all of the UDP-glucuronic acid is synthesized through the conversion of UDP-glucose. If a major salvage pathway existed in C. neoformans, one can predict that the residual UDP-glucuronic acid would compensate at least partly for the UDP-glucose dehydrogenase. UGD1 appeared completely required for expression of two of the three major attributes necessary for virulence in C. neoformans, i.e., the presence of a capsule and the ability to grow ...
Intestinal absorption was investigated in six patients with a diagnosis of primary hypogammaglobulinemia. Malabsorption was found in four patients. Low serum vitamin E levels, decreased D-xylose absorption, and increased 5-hydroxyindoleacetic acid excretion in the urine correlated with malabsorption with minor exceptions. Five patients were subjected to jejunal biopsies, and nodular lymphoid hyperplasia was found on at least one examination in each of these patients. In addition, partial to complete mucosal atrophy characterized biopsy specimens from four patients and correlated with steatorrhea with one exception. Although gastric achlorhydria (two patients), minimal to moderate pancreatic insufficiency (two patients), significant intestinal intraluminal bacterial overgrowth (three patients), and Giardia lamblia (five patients) were found, the evidence suggests that the most significant cause of malabsorption in these hypogammaglobulinemic patients is an intestinal mucosal lesion. Reversibility ...
Metabolic Engineering of Thermophilic Bacillus licheniformis for Chiral Pure D-2,3-Butanediol Production Another BDO, 2,3-Butanediol, is also a potential fuel and a platform chemical. Organisms that natively produce the chemical are pathogenic and can only form the product with fermentations at 37°C. To transform the Bacillus licheniformis they had to use a protoplast fusion method. They were able to utilize xylose as a feedstock at 50°C to create 2,3-Butanediol. This will be helpful to utilize lignocellulose substrates as higher temperatures are helpful because of higher rates of degradation and fewer enzymes are need to be added [13]. Metabolic engineering of a thermophilic bacterium to produce ethanol at high yield In this paper the authors used Thermoanaerobacterium saccharolyticum and made knockouts in the genes for acetate kinase, phosphate acetyltransferase, and L-lactate dehydrogenase. Their strain was able to produce high yields of ethanol as the only measurable fermentation ...
Bovine prothrombin contains three asparagine-linked sugar chains in 1 molecule. The sugar chains were quantitatively released from the polypeptide backbone by hydrazinolysis. All of the oligosaccharides thus obtained contain N-acetylneuraminic acid.
TY - JOUR. T1 - Effects of pH and high ionic strength on the adsorption and activity of native and mutated cellobiohydrolase I from Trichoderma reesei. AU - Reinikainen, Tapani. AU - Teleman, Olle. AU - Teeri, Tuula. N1 - Project code: BEL4319. PY - 1995. Y1 - 1995. N2 - Cellobiohydrolase I (CBHI) is the major cellulase of Trichoderma reesei. The enzyme contains a discrete cellulose‐binding domain (CBD), which increases its binding and activity on crystalline cellulose. We studied cellulase‐cellulose interactions using site‐directed mutagenesis on the basis of the three‐dimensional structure of the CBD of CBHI. Three mutant proteins which have earlier been produced in Saccharomyces cerevisiae were expressed in the native host organism. The data presented here support the hypothesis that a conserved tyrosine (Y492) located on the flat and more hydrophilic surface of the CBD is essential for the functionality. The data also suggest that the more hydrophobic surface is not directly involved ...
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Pretreated dirty cotton residue (PDCR) from the textile industry was used as an alternative carbon source for the submerged cultivation of Aspergillus oryzae and the production of xylanases. The filtered culture supernatant was fractionated by ultrafiltration followed by three chromatographic steps, which resulted in the isolation of a homogeneous low-molecular-weight xylanase (Xyl-O1) with a mass of 21.5 kDa as determined by sodium dodecyl sulfate-polyacrilamide gel electrophoresis (SDS-PAGE) co-polymerized with 0.1% oat spelt xylan. Enzyme catalysis was the most efficient at 50 °C and pH 6.0. The Km values (mg·mL−1) for the soluble fraction of oat spelt and birchwood xylans were 10.05 and 3.34, respectively. Xyl-O1 was more stable in the presence of 5,5-dithio-bis-(2-nitrobenzoic acid) (DTNB), 1,4-dithiothreitol (DTT), l-cysteine or β-mercaptoethanol, which increased the rate of catalysis by 40%, 14%, 40% or 37%, respectively. The enzyme stability was improved at pH 7.0 in the presence of 20 mM l
The London School of Economics (officially the London School of Economics and Political Science, often referred to as LSE or the LSE) is a public research university located in London, England, and a member institution of the federal University of London. Founded in 1895 by Fabian Society members Sidney Webb, Beatrice Webb, Graham Wallas, and George Bernard Shaw for the betterment of society, LSE joined the University of London in 1900 and established its first degree courses under the auspices of the University in 1901.[6] LSE started awarding its own degrees in its own name in 2008,[7] prior to which it awarded degrees of the University of London. The LSE is located in Westminster, central London, near the boundary between Covent Garden and Holborn. The area is historically known as Clare Market. The LSE has more than 11,000 students, just under seventy percent of whom come from outside the UK, and 3,300 staff.[8] It had an income of £415.1 million in 2018/19, of which £32.1 million was from ...
Plant cells are surrounded by a strong polysaccharide-rich cell wall that aids in determining the overall form, growth and development of the plant body. Indeed, the unique shapes of the 40-odd cell types in plants are determined by their walls, as removal of the cell wall results in spherical protoplasts that are amorphic. Hence, assembly and remodeling of the wall is essential in plant development. Most plant cell walls are composed of a framework of cellulose microfibrils that are cross-linked to each other by heteropolysaccharides. The cell walls are highly dynamic and adapt to the changing requirements of the plant during growth. However, despite the importance of plant cell walls for plant growth and for applications that we use in our daily life such as food, feed and fuel, comparatively little is known about how they are synthesized and modified. In this Cell Science at a Glance article and accompanying poster, we aim to illustrate the underpinning cell biology of the synthesis of wall ...
The ability to deconstruct plant biomass without conventional pretreatment has made members of the genus Caldicellulosiruptor the target of investigation for the consolidated processing of lignocellulosic biomass to biofuels and bioproducts. These Gram-positive bacteria are hyperthermophilic anaerobes and the most thermophilic cellulolytic organisms so far described. They use both C5 and C6 sugars simultaneously and have the ability to grow well on xylan, a major component of plant cell walls. This is an important advantage for their use to efficiently convert biomass at yields sufficient for an industrial process. For commodity chemicals, yield from substrate is perhaps the most important economic factor. In an attempt to improve even further the ability of C. bescii to use xylan, we introduced two xylanases from Acidothermus cellulolyticus. Acel_0180 includes tandem carbohydrate-binding modules (CBM2 and CBM3) located at the C-terminus, one of which, CBM2, is not present in C. bescii. Also, ...
article{569d6702-1354-4b3b-8b97-3c11c9807854, abstract = {Metabolic stress is a phenomenon often discussed in conjunction with recombinant protein production in Escherichia coli. This investigation shows how heterologous protein production, and the presence of host cell proteases is related to: i) IPTG induction, ii) cell mass concentration at the time of induction and iii) the presence of metabolites (glutamic acid or those from TSB) during the post induction phase of high-cell-density (HCD) fed-batch cultivations. Two thermostable xylanase variants and one thermostable cellulase, all originating from Rhodothermus marinus were expressed in E. coli strain BL21 (DE3). A three-fold difference in the specific activity of both xylanase variants [between 7000 and 21000 U / (g cdw)], was observed under the different conditions tested. Upon induction at high cell-mass concentrations employing a nutrient feed devoid of the metabolites above, the specific activity of the xylanase variants, was initially ...
Busse-Wicher, M., Gomes, T. C. F., Tryfona, T., Nikolovski, N., Stott, K., Grantham, N. J., Bolam, D. N., Skaf, M. S. and Dupree, P. (2014), The pattern of xylan acetylation suggests xylan may interact with cellulose microfibrils as a twofold helical screw in the secondary plant cell wall of Arabidopsis thaliana. The Plant Journal, 79: 492-506. doi: 10.1111/tpj.12575 ...