Glucose Homopolymer Research Articles

Dynamics of amylopectin granule accumulation during the course of the chronic Toxoplasma infection is linked to intra-cyst bradyzoite replication.

The contribution of amylopectin granules (AG), comprised of a branched chain storage homopolymer of glucose, to the maintenance and progression of the chronic Toxoplasma gondii infection has remained undefined. Here we describe the role of AG in the physiology of encysted bradyzoites by using a custom developed imaging-based application AmyloQuant that permitted quantification of relative levels of AG within in vivo derived tissue cysts during the initiation and maturation of the chronic infection. Our findings establish that AG are dynamic entities, exhibiting considerable heterogeneity among tissue cysts at all post infection time points examined. Quantification of relative AG levels within tissue cysts exposes a previously unrecognized temporal cycle defined by distinct phases of AG accumulation and utilization over the first 6 weeks of the chronic phase. This AG cycle is temporally coordinated with overall bradyzoite mitochondrial activity implicating amylopectin in the maintenance and progression of the chronic infection. In addition, the staging of AG accumulation and its rapid utilization within encysted bradyzoites was associated with a burst of coordinated replication. As such our findings suggest that AG levels within individual bradyzoites, and across bradyzoites within tissue cysts may represent a key component in the licensing of bradyzoite replication, intimately linking stored metabolic potential to the course of the chronic infection. This extends the impact of AG beyond the previously assigned role that focused exclusively on parasite transmission. These findings force a fundamental reassessment of the chronic Toxoplasma infection, highlighting the critical need to address the temporal progression of this crucial stage in the parasite life cycle.

Identification and characterisation of dextran produced by a novel high yielding Weissella cibaria Fiplydextran strain

An exopolysaccharide (EPS)-producing bacterial strain was isolated from fermented soy milk and identified as Weissella cibaria strain Fiplydextran through morphological, biochemical and 16S rDNA sequence analysis. Here, we report the optimisation of cultural conditions for the organism to achieve maximum EPS production, along with its molecular characterisation, functional properties, and prebiotic potential. The exceptionally high EPS yield (0.61 g per g of sucrose) was obtained from the optimised medium (200 g/L of sucrose, 15 g/L of yeast extract) at 30 °C after 48 h. HPAEC-PAD analysis revealed that the EPS is homopolymer of glucose having Mw as 3.23 × 107 Da determined using viscosity method. Methylation analysis and NMR results confirmed the EPS as dextran with α (1 → 6)-linkage (96.5 %) as main chain and α (1 → 3)- as branch chain linkage (3.5 %). Thermogravimetric analysis exhibited higher thermal stability of EPS. The EPS was observed to support the growth of Bacteroides spp. in pure culture form but not that of Lactobacillus or Bifidobacterium spp. However, a low level of bifidogenic activity was observed upon use of mixed culture of B. fragilis and B. longum. The research implies industrial applications of W. cibaria Fiplydextran for the production of high molecular weight dextran with better yield.

High molecular weight glucose homopolymer of broccoli (Brassica oleracea var. italica) stimulates both invertebrate and mammalian immune systems

There is widespread interest in the immunostimulatory effects of food-derived substances that are expected to contribute to improving human health. Broccoli (Brassica oleracea var. italica) has been shown to contain potent polysaccharides for developing food materials with immunomodulatory function. In this study, immunostimulatory activity of previously uncharacterized broccoli polysaccharides was assessed using a silkworm (Bombyx mori) immunological assay (using muscle contraction as an index) across 10 commercial and 17 experimental cultivars of broccoli. For the commercial cultivars, there was a significant variation in specific activity (units/mg, measured by the silkworm-based immunological assay). For the experimental cultivars, a cultivar “winter dome” showed the highest activity. We further purified the immunostimulatory polysaccharides of “winter dome” by gel filtration. Using the silkworm-based assay, we found that the peak fraction (“Fraction II”) contained the active substance with higher specific activity than previously reported active substances (e.g., glucans). The substance appeared a heterogeneous molecular weight of more than 270 kDa. The major sugar composition of Fraction II was glucose, suggesting that glucose homopolymer is responsible for the activity. Further, Fraction II induced cytokine productions both in the silkworm (production of active B. mori paralytic peptide (BmPP) in vivo) and mouse (production of TNFα in vitro) immune system. These results suggest that glucose homopolymer of broccoli induces cytokines both in insect and mammalian immune systems, providing molecular insights to our understanding about how plant-derived substances interact with animal immune system.

Separation of saccharides using fullerene-bonded silica monolithic columns via \u03c0 interactions in liquid chromatography

We report on a potential method to separate sugars by using the specific interaction between fullerenes and saccharides in liquid chromatography (LC). Aromatic rings with high electron density are believed to interact strongly with saccharides due to CH–π and/or OH–π interactions. In this study, the fullerene-bonded columns were used to separate saccharides by LC under aqueous conditions. As a result, 2-aminobenzamide-labeled glucose homopolymer (Glcs) was effectively separated by both C60 and C70 columns in the range of Glc-1 to Glc-20 and high blood glucose level being retained in greater quantity. Furthermore, similar separations were identified by LC–mass spectrometry with non-labeled glucose homopolymers. Theoretical study based on molecular dynamics and DFT calculation demonstrated that a supramolecular complex of saccharide–fullerene was formed through CH–π and/or OH–π interactions, and that the interactions between saccharide and fullerene increase with the increase units of the saccharide. Additionally, the C60 column retained disaccharides containing maltose, trehalose, and sucrose. In this case, it was assumed that the retention rates were determined by the difference of the dipole moment in each saccharide. These results suggest that the dipole-induced dipole interaction was dominant, and that maltose—with the higher dipole moment—was more strongly retained compared to other disaccharides having lower dipole moment.

Characterization of glycogen molecular structure in the worm Caenorhabditis elegans

Glycogen, a glucose homopolymer with many glucose chains, is the primary blood-sugar reservoir in many organisms. It comprises β particles (∼20 nm) which can bind together to form large α particles with a rosette morphology. When dimethyl sulfoxide (DMSO) is added to glycogen from diabetic livers, α particles break apart to β particles (‘fragility’), possibly due to H-bond disruption; this is not seen in healthy livers. Glycogen α and β particles, and α-particle fragility, are observed in mammals and bacteria, and are examined here in the worm Caenorhabditis elegans, with glycogen from two C. elegans strains, cultured in normal and high-glucose conditions. There were mainly β particles, with some large α particles. Most particles were fragile in DMSO. Growing in a high-glucose medium results in more long chains and more fragility, consistent with previous observations in diabetic animal models. Why high glucose levels facilitate fragility is worthy of further investigation.

Response Surface Methodology Optimization of Production of Cellulase by Trichoderma Reesei using Mango Peel

Progression of the lifestyle vehicle for cellulose age using Trichoderma reesei was finished. The creating use of mixes to override traditional manufactured change methods is focused by an objective for better age money related angles. Celluloses are lignocelluloses materials are disgraceful endless resources available in enormous sums. Cellulose is a homopolymer of glucose. Box-Behken method was used for upgrade of tri – choderma reesei using mango strip.

X-ray crystallographic analysis of the catalytic domain of α-1,3-glucanase FH1 from Paenibacillus glycanilyticus overexpressed in Brevibacillus choshinensis.

α-1,3-Glucanase hydrolyzes α-1,3-glucan, an insoluble linear α-1,3-linked homopolymer of glucose that is found in the extracellular polysaccharides produced by oral streptococci in dental plaque and in fungal cell walls. This enzyme could be of application in dental care and the development of fungal cell-wall lytic enzymes, but its three-dimensional structure has not been available to date. In this study, the recombinant catalytic domain of α-1,3-glucanase FH1 from Paenibacillus glycanilyticus FH11, which is classified into glycoside hydrolase family 87, was prepared using a Brevibacillus choshinensis expression system and purified in a soluble form. Crystals of the purified protein were produced by the sitting-drop vapor-diffusion method. Diffraction data were collected to a resolution of 1.6 Å using synchrotron radiation. The crystals obtained belonged to the tetragonal space group P41212 or P43212, with unit-cell parameters a=b=132.6, c = 76.1 Å. The space group and unit-cell parameters suggest that there is one molecule in the asymmetric unit.

Spatial heterogeneity of glycogen and its metabolizing enzymes in Aspergillus nidulans hyphal tip cells

Glycogen is a homopolymer of glucose and a ubiquitous cellular-storage carbon. This study investigated which Aspergillus nidulans genes are involved in glycogen metabolism. Gene disruptants of predicted glycogen synthase (gsyA) and glycogenin (glgA) genes accumulated less cellular glycogen than the wild type strain, indicating that GsyA and GlgA synthesize glycogen similarly to other eukaryotes. Meanwhile, gene disruption of gphA encoding glycogen phosphorylase increased the amount of glycogen to a higher degree than wild type during the stationary phase that accompanies carbon-source limitation. GFP-tagged GsyA and GphA were distributed in the cytosol and formed punctate and filamentous structures, respectively. Carbon starvation resulted in elongated GphA-GFP filaments and increased numbers of filaments. These structures were more frequently located in the basal regions of tip cells and adjacent cells than in the apical regions of tip cells. Cellular glycogen visualized by incorporation of a fluorescent glucose analog accumulated in cytoplasmic puncta that were more prevalent in the basal regions, a pattern similar to that seen for GsyA. The colocalization of glycogen and GsyA at punctate structures in tip and sub-apical cells likely represents the cellular machinery for synthesizing glycogen. More frequent colocalization in the basal, rather than tip cell apical regions indicated that tip cells have differentiated subcellular regions for glycogen synthesis. Our findings regarding glycogen, GsyA and GphA distribution evoke the spatial heterogeneity of glycogen metabolism in fungal hyphae.

α-1,3-Glucanase: present situation and prospect of research.

α-1,3-Glucanases hydrolyze α-1,3-glucan which is an insoluble linear α-1,3-linked homopolymer of glucose and these enzymes are classified into two families of glycoside hydrolases on the basis of amino acid sequence similarity; type-71 α-1,3-glucanases found in fungi and type-87 enzymes in bacteria. α-1,3-Glucan (also called 'mutan') is a major component of dental plaque formed by oral Streptococci and has important physiological roles in various fungal species, including as a component of cell walls, an endogenous carbon source for sexual development, and a virulent factor. Considering these backgrounds, α-1,3-glucanases have been investigated from the perspectives of applications to dental care and development of cell-wall lytic enzymes. Compared with information regarding other glycoside hydrolases such as amylases, cellulases, chitinases, and β-glucanases, there is limited biochemical and structural information available regarding α-1,3-glucanase. Further research on α-1,3-glucanases on enzyme application to dental care and biological control of pathogenic fungi is expected. In this mini-review, we briefly describe how α-1,3-glucanases are categorized and characterized and present our study findings regarding α-1,3-glucanase from Bacillus circulans KA-304. Furthermore, we briefly discuss potential future applications of α-1,3-glucanases.

Physical, functional and structural characterization of the cell wall fractions from baker’s yeast Saccharomyces cerevisiae

The yeast cell wall of Saccharomyces cerevisiae is an important source of β-d-glucan, a glucose homopolymer with many functional, nutritional and human health benefits. In the present study, the yeast cell wall fractionation process involving enzymatic treatments (savinase and lipolase enzymes) affected most of the physical and functional characteristics of extracted fractions. Thus, the fractionation process showed that β-d-glucan fraction F4 had significantly higher swelling power and fat binding capacity compared to other fractions (F1, F2 and F3). It also exhibited a viscosity of 652.12mPas and a high degree of brightness of extracted β-d-glucan fraction. Moreover, the fractionation process seemed to have an effect on structural and thermal properties of extracted fractions. Overall, results showed that yeast β-d-glucan had good potential for use as a prebiotic ingredient in food, as well as medicinal and pharmaceutical products.

Physico-chemical Characterization of Exopolysaccharides of Potential Probiotic Enterococcus faecium Isolates from Infants’gut

Microbial exopolysaccharides (EPS) may have technological applications in food and pharmaceutical industries, and in environmental health. EPS may be used in foods as natural thickening, stabilizing, bodying or gelling agent, and/or as emulsifiers or as fat replacer. In addition, EPS has been reported to have health augmenting features such as prebiotic, immunostimulatory, anti-tumor and hypocholesterolemic properties. EPS producing probiotics bacteria may help enhancing organoleptic properties of fermented foods. In present study, Enterococcus faecium strains viz. Enterococcus faecium 1.1, E. faecium 2.0 and E. faecium 4.0, which had several probiotically important attributes, were investigated for their EPS producing potential. E. faecium 4.0 produced highest yield of EPS (470 mg/L) and was followed by E. faecium 1.1 (220 mg/L) and E. faecium 2.0 (180 mg/L). FTIR analysis showed that EPS from all the three E. faecium strains was homopolymer of glucose. Degradation temperatures of EPS from three E. faecium strains varied in the range of 270.4°C-279.3°C as studied by thermal gravimetric analysis. Differential scanning calorimetry of EPS from E. faecium 1.1, E. faecium 2.0 and E. faecium 4.0 showed the melting point of 55.9°C, 88.6°C and 83.5°C; and enthalpy of 102.5, 56.03, and 213.9 J/g, respectively. EPS from all the three E. faecium strains expressed growth inhibition of E. coli. Purified EPS from all three E. faecium strains exhibited excellent emulsification properties i.e. 96.70 % (E. faecium 1.1), 96.78 % (E. faecium 2.0) and 97.77 % (E. faecium 4.0). Keywords: Enterococcus faecium, exopolysaccharide, FTIR, emulsifying activity.

Enzymatic process for the fractionation of baker’s yeast cell wall (Saccharomyces cerevisiae)

β-Glucans, homopolymers of glucose, are widespread in many microorganisms, mushrooms and plants. They have attracted attention because of their bioactive and medicinal functions. One important source of β-glucans is the cell wall of yeasts, especially that of baker’s yeast Saccharomyces cerevisiae. Several processes for the isolation of β-glucans, using alkali, acid or a combination of both, result in degradation of the polymeric chains. In this paper, we have an enzymatic process for the isolation of glucans from yeast cell walls. As a result, β-glucans were obtained in a yield of 18.0% of the original ratio in the yeast cell walls. Therefore, this isolation process gave a better yield and higher β-glucan content than did traditional isolation methods. Furthermore, results showed that each extraction step of β-glucan had a significant effects on its chemical properties.

Physiologic and metabolic characterization of a new marine isolate (BM39) of Pantoea sp. producing high levels of exopolysaccharide

BackgroundMarine environments are the widest fonts of biodiversity representing a resource of both unexploited or unknown microorganisms and new substances having potential applications. Among microbial products, exopolysaccharides (EPS) have many physiological functions and practical applications. Since EPS production by many bacteria is too scarce for practical use and only few species are known for their high levels of production, the search of new high EPS producers is of paramount importance. Many marine bacteria, that produce EPS to cope with strong environmental stress, could be potentially exploited at the industrial level.ResultsA novel bacterium, strain BM39, previously isolated from sediments collected in the Tyrrhenian Sea, was selected for its production of very high levels of EPS. BM39 was affiliated to Pantoea sp. (Enterobacteriaceae) by 16S rRNA gene sequencing and biochemical tests. According to the phylogenetic tree, this strain, being quite far from the closest known Pantoea species (96% identity with P. agglomerans and P. ananatis) could belong to a new species. EPS production was fast (maximum of ca. 21 g/L in 24 h on glucose medium) and mainly obtained during the exponential growth. Preliminary characterization, carried out by thin layer and gel filtration chromatography, showed that the EPS, being a glucose homopolymer with MW of ca. 830 kDa, appeared to be different from those of other bacteria of same genus. The bacterium showed a typical slightly halophilic behavior growing optimally at NaCl 40 ‰ (growing range 0-100 ‰). Flow cytometry studies indicated that good cell survival was maintained for 24 h at 120 ‰. Survival decreased dramatically with the increase of salinity being only 1 h at 280 ‰. The biochemical characterization, carried out with the Biolog system, showed that MB39 had a rather limited metabolic capacity. Its ability, rather lower than that of P. agglomerans, was almost only confined to the metabolization of simple sugars and their derivatives. Few alcohols, organic acids and nitrogen compounds were partially used too.ConclusionsStrain BM39, probably belonging to a new species, due to its remarkable EPS production, comparable to those of known industrial bacterial producers, could be suggested as a new microorganism for industrial applications.

Moisture diffusivity in food materials

This paper investigates whether moisture diffusion can be predicted for food materials. We focus especially on mixtures of glucose homopolymers and water. The predictions are based on three theories: (1) the Darken relation, linking the mutual diffusivity to the self diffusivities, (2) the generalised Stokes–Einstein relation for the solute self diffusivity, and (3) the free volume theory for water self diffusivity. Using literature data obtained for the whole class of glucose homopolymer, we show that these theories predict the moisture diffusivity for the whole range of volume fractions, from zero to one, and a broad range of temperatures. Furthermore, we show that the theories equally holds for other hydrophilic biopolymers one finds in food. In the concentrated regime, all experimental data collapse to a single curve. This universal behaviour arises because these biopolymers form a hydrogen bonded network, where water molecules move via rearrangement of the free volume.

Cyclic-β-glucans of Rhizobium (Sinorhizobium) sp. strain NGR234 are required for hypo-osmotic adaptation, motility, and efficient symbiosis with host plants

Cyclic-β-glucans (CβG) consist of cyclic homo-polymers of glucose that are present in the periplasmic space of many Gram-negative bacteria. A number of studies have demonstrated their importance for bacterial infection of plant and animal cells. In this study, a mutant of Rhizobium (Sinorhizobium) sp. strain NGR234 (NGR234) was generated in the cyclic glucan synthase (ndvB)-encoding gene. The great majority of CβG produced by wild-type NGR234 are negatively charged and substituted. The ndvB mutation abolished CβG biosynthesis. We found that, in NGR234, a functional ndvB gene is essential for hypo-osmotic adaptation and swimming, attachment to the roots, and efficient infection of Vigna unguiculata and Leucaena leucocephala.

Thermodynamics of meat proteins

We describe the water activity of meat, being a mixture of proteins, salts and water, by the Free-Volume-Flory–Huggins (FVFH) theory augmented with the equation. Earlier, the FVFH theory is successfully applied to describe the thermodynamics to glucose homopolymers like starch, dextrans and maltodextrins. We have estimated parameter values from sorption isotherms of unsalted, lean meat products and model proteins like elastin and gelatin. These parameter values are quite similar to those found for glucose homopolymers. Moist meat products are also characterized with a water holding capacity, which we can describe with the Flory–Rehner theory. Subsequently, we have been able to predict very accurately the sorption isotherms of salted meat products and gelatin gels. Hence, the thermodynamics of foods can be described without the use of the controversial concept of bound/unfreezable water. Comparison of FVFH theory combined with Flory–Rehner theory to concentrated systems shows that the theory contains terms that are double counting for elastic effects – which makes us conclude that the validity of the Flory–Rehner theory is restricted to the (semi)-dilute regime. A complete thermodynamic description is proposed via mathematical matching of the FVFH and Flory–Rehner theory.

Prediction of the state diagram of starchwater mixtures using the Flory–Huggins free volume theory

In this paper we analyse the phase and state transitions of starch and other glucose homopolymers and oligomers using the free volume extension of the Flory–Huggins theory by Vrentas and Vrentas, combined with the Couchman–Karasz theory for the glass transition. Using scaling relations of model parameters with molar weight we have obtained accurate predictions of moisture sorption and the freezing, boiling, and melting data obtained from literature for starch, dextrans, pullulan and maltodextrins. With the estimated model parameters we can construct the complete state diagram for starch, which can now be used as a quantitative tool for design and analysis of food structuring processes.

A study on chemical constituents and sugars extraction from spent coffee grounds

Spent coffee grounds (SCG), the residual materials obtained during the processing of raw coffee powder to prepare instant coffee, are the main coffee industry residues. In the present work, this material was chemically characterized and subsequently submitted to a dilute acid hydrolysis aiming to recover the hemicellulose sugars. Reactions were performed according to experimental designs to verify the effects of the variables H 2SO 4 concentration, liquid-to-solid ratio, temperature, and reaction time, on the efficiency of hydrolysis. SCG was found to be rich in sugars (45.3%, w/w), among of which hemicellulose (constituted by mannose, galactose, and arabinose) and cellulose (glucose homopolymer) correspond to 36.7% (w/w) and 8.6% (w/w), respectively. Optimal conditions for hemicellulose sugars extraction consisted in using 100 mg acid/g dry matter, 10 g liquid/g solid, at 163 °C for 45 min. Under these conditions, hydrolysis efficiencies of 100%, 77.4%, and 89.5% may be achieved for galactan, mannan, and arabinan, respectively, corresponding to a hemicellulose hydrolysis efficiency of 87.4%.

Beta-1,3-glucan effect on sow antibody production and passive immunisation of progeny

β-glucans are glucose homopolymers known to modulate immunity. Here, the β-glucan effect on sow antibody production and passive immunisation of neonatal pigs was analysed. Treatments included: (1) corn-soy fed Control group; (2) β-glucan; (3) Actinobacillus pleuropneumoniae (App) vaccination; and (4) β-glucan + App vaccination. Birth and weaning weights were not affected (P>0.05) by treatment. Independent of treatment, IgA, IgG and IgM in colostrum were elevated and declined rapidly. Vaccination against App resulted in an increase (P<0.05) in IgG and IgA specific for App serotypes 1, 5 and 7 in colostrum and milk, and a corresponding increase (P<0.05) in serum in pigs at 4 d of age. However, β-glucan did not enhance specific App antibodies in pig serum. While the dosage used here did not enhance passive immunisation in pigs, β-glucan can be potentially efficacious as an oral adjuvant to enhance immunoglobulin production in response to vaccination.

Optimized methodology for extraction of (1 → 3)(1 → 6)-β- d-glucan from Saccharomyces cerevisiae and in vitro evaluation of the cytotoxicity and genotoxicity of the corresponding carboxymethyl derivative

The cell wall of Saccharomyces cerevisiae is an important source of β- d-glucan, a glucose homopolymer with immunostimulant properties. The standard methodologies described for its extraction involve acid and alkaline washings, which degrade part of its glucose chains and reduce the final yield. In the present study, an optimized methodology for extraction of β- d-glucan from S. cerevisiae cells, involving sonication and enzyme treatment, with a yield of 11.08 ± 0.19%, was developed. The high-purity (1 → 3)(1 → 6)-β- d-glucan was derivatized to carboxymethyl-glucan (CM-G). In vitro tests with CM-G in Chinese hamster epithelial cells (CHO-k1) did not reveal any cytotoxic or genotoxic effects or influences of this molecule on cell viability. The method described here is a convenient alternative for the extraction of (1 → 3)(1 → 6)-β- d-glucan under mild conditions without the generation of wastes that could be potentially harmful to the environment.