Constituent Sugars Research Articles

Keep your friends close and your competitors closer: novel interspecies interaction in desert biological sand crusts

ABSTRACT The green alga Chlorella sp. and the filamentous cyanobacterium Leptolyngbya sp., regularly cope with various stressors including frequent hydration–desiccation cycles. When grown in axenic cultures, Chlorella sp. is unable to resurrect even after very slow desiccation unless desiccation takes place in the presence of Leptolyngbya sp. or a lysate thereof. When Chlorella sp. was provided with extracellular polysaccharides from Leptolyngbya sp., or its main sugar constituents, it was able to be resurrected after mild desiccation. These findings suggest that desiccation tolerance of Chlorella sp. in the field depends on the presence of Leptolyngbya sp. or components thereof. Chlorella sp. was originally isolated as a contaminant in a decaying stationary culture of Leptolyngbya sp. that was established by the addition of a cyanobacterial growth media to biological soil crusts. Co-incubation with a dialysis tube containing Leptolyngbya sp. severely inhibited growth of Chlorella sp. These data suggest that secondary metabolites excreted by Leptolyngbya sp., the nature of which is yet unknown, inhibit growth of Chlorella sp. Thus, though Leptolyngbya sp. enables the survival of Chlorella sp. in a desert habitat, it simultaneously inhibits growth of this potential competitor. The combination of positive and negative effects of Leptolyngbya sp. on fitness of Chlorella sp. creates a scenario in which the former tightly controls the abundance of the latter.

Comparable metabolic effects of isocaloric sucrose and glucose solutions in rats

Much of the global increase in sugar intake is attributable to rising consumption of sugar-sweetened beverages (SSBs). Because people compensate poorly for liquid calories, SSB consumption increases total energy intake, raising the risk of harmful metabolic effects in addition to possible effects of sugars per se. Glucose and fructose, the constituent sugars in sucrose, can exert distinct effects on metabolism and also differ in their satiating properties, suggesting that compensation for the calories in these sugars may also vary. In light of claims that the fructose within sucrose is particularly harmful, the present study compared the effects of giving rats access to either a sucrose or an isoenergetic glucose solution. Adult male rats were fed standard chow and water supplemented with 95 ml of 10% glucose (Glucose group; n = 10), 9% sucrose solution (Sucrose group; n = 10) or water only (Control group; n = 10) daily for 7 weeks. Sugar-fed groups had higher total energy intakes than the Control group, but the extent of this incomplete compensation did not vary between Sucrose and Glucose groups. In a short-term compensation test, sugar groups were less sensitive to the effects of a sweet pre-meal, with no differences between the Glucose and Sucrose groups. Relative to water, both sugars reduced insulin sensitivity after 4 weeks on the diets and elevated fat mass at 7 weeks. Results suggest that sucrose and glucose induce comparable metabolic impairments and alter the homeostatic regulation of food intake even under conditions where daily access is capped.

Characterization of two sugar transporters responsible for efficient xylose uptake in an oleaginous yeast Candida tropicalis SY005

Microbial conversion of lignocellulosic feedstock to the target bioproduct requires efficient assimilation of its constituent sugars, a large part of which comprises of glucose and xylose. This study aims to identify and characterize sugar transporters capable of xylose uptake in an oleaginous strain of the industrially relevant yeast Candida tropicalis. In silico database mining resulted in two sugar transporter proteins- CtStp1 and CtStp2, containing conserved amino acid residues and motifs that have been previously reported to be involved in xylose transport in other organisms. Several softwares predicted the likelihood of 10–12 transmembrane (TM) helices to be present in both the Stps, while molecular modelling showed 12 TM helices that were organized into a typical structure found in the major facilitator superfamily of transporters. Docking with different sugars also predicted favorable interactions. Heterologous expression in a Saccharomyces cerevisiae strain harboring functional xylose metabolic genes validated the broad substrate specificity of the two Stps. Each transporter supported prominent growth of recombinant S. cerevisiae strains on six sugars including xylose at various concentrations. Expression of CtSTP1 and CtSTP2 along with the xylose metabolic genes in yeast transformants grown in presence of xylose was confirmed by transcript detection. Growth curve and sugar consumption profiles revealed uptake of both glucose and xylose simultaneously by the recombinant yeast strains, though CtStp1 showed relatively less effect of glucose repression in mixed sugars and was a better transporter of xylose than CtStp2. Such glucose-xylose utilizing efficient transporters can be effective tools for developing co-fermenting yeasts through genetic engineering in future, with noteworthy applications in renewable biomass utilization.

Bioactive compounds and functional potential of Uapaca kirkiana (Muell. arg.) fruits

Consumption of Uapaca kirkiana indigenous fruit by the local populace is growing in popularity because of the acclaimed health and functional benefits. The aim of the study was to determine the bioactive compounds and functional properties of the U. kirkiana fruit. Besides the fruit’s pulp yield, the bioactive phytochemical constituent, physicochemical properties and functional characteristics of the pulp were analysed. The sugar, starch, minerals, and ascorbic acid constituents of the fruit pulp were, respectively determined using the following instruments: brix refractometer, megazyme kit, inductive coupled plasma-optical emission spectrometer and 2,6- dichlorophenolindophenol (DCPIP) titration test. The total phenolic content (TPC), tannin, and flavonoid contents were evaluated using Folin Ciocalteau test, tannin binding test and vanillin test, respectively. The average weight of the U. kirkiana fruits harvested from three regions having different climatic conditions ranged from 23.56 to 34.20 g per fruit. The mean pulp weight was from 12.15 g/100 g to 15.09 g/100 g per fruit. The biochemical and functional parameters obtained include total titratable acid (0.3 - 0.48 g/kg), antioxidantactivity (34.96 - 36.68%), vitamin C (15.74 - 16.63 mg/100 g), dry matter content (28.81 - 29.38%), pH (4.3 - 4.6) and sugar content (20.29 - 21.87 g/100 g). Fructose was the dominant sugar (10.12-11.0 g/100 g). Preliminary phytochemical screening of the pulp indicated the presence of tannins, flavonoids, amino acids and carbohydrate content. Total phenolic content ranged from 67.0 to 82.5 µg GAE/g. The essential elements constituent evaluation of the pulp revealed that Fe content was 11.3 - 12.2 mg/100 g, K (383.07 - 439.8 mg/100 g), Mg (28.7 - 35.1 mg/100 g), Ca (16.4 - 17.3 mg/100 g), P (13.4 - 15.1 mg/100 g), Na (9.08 - 9.78 mg/100 g), Cu (0.8 - 0.94 mg/100 g) and Zn (0.87 - 0.94 mg/100 g). This study, besides establishing U. kirkiana fruit as a good source of micronutrients (Fe, Cu, Zn), reveals that the fruit is also an excellent source of phenolic compounds, vitamin C and sugars, hence use as a dietary supplement may combat some nutritional deficiencies. We, therefore, recommend U. kirkiana fruits to be used to produce nutritive functional foods with health benefits such as probiotic jams and as an additive. Key words: Indigenous fruit, micronutrients, phenolic, pulp, phytochemicals, U.kirkiana, megazyme kit

Evaluating the use of preservatives on the shelf life of tender coconut water

Tender coconut water is a sweet, delicious and refreshing natural beverage. The sugar and mineral constituents attributes to the pleasant taste of tender coconut water. Due to the presence of sugars and a number of plant enzymes, tender coconut water has a strong tendency to undergo biochemical changes and spoilage, once the nut is harvested from the tree. Furthermore, coconut as a whole is bulky and perishable without proper packaging, which challenges the task of transportation of tender coconut water over a long distance. So, an attempt has been made to extend its shelf life in bottles, which will lead to easy transport and easy to serve. Design of the process was developed by considering the dependent variables (microbial population, sensory attributes) and independent variables (time, temperature, preservatives). The preservatives used for this study include potassium sorbate and sodium benzoate. During thermal sterilization process the flavour components were destroyed and palatability was not good and hence in-bottle sterilization was adopted in this study to retain the flavours and preserve tender coconut water. It was found that the tender coconut water preserved by the treatments T11 (Potassium Sorbate (@ 300 ppm) at 80 °C for 180 s) in the in-bottle sterilization had a shelf life of 3 months and T27 (sodium benzoate (@ 350 ppm) at 80 °C for 180 s) in the in-bottle sterilization was acceptable with the maximum shelf life of 1 month. By adopting this preservation technique, tender coconut water could be effectively stored and used for 70 days under refrigerated condition (4 °C).

Characterization and bioactivities of exopolysaccharide produced from probiotic Lactobacillus plantarum 47FE and Lactobacillus pentosus 68FE.

This investigation attempts to assess the exopolysaccharide (EPS) production from probiotic Lactobacilli isolated from Egyptian cheese products. Three Lactobacillus isolates (14FE, 47FE, and 68FE) were declared possible probiotic features. These isolates displayed neither hemolytic nor gelatinase activity. They were also susceptible to most antibiotics and confirmed utilizing 16S rRNA namely, Lactobacillus pentosus 14FE, Lactobacillus plantarum 47FE, and Lactobacillus pentosus 68FE with accession number MK616467, MK616469, and MK616468, respectively. All of them had the aptitude to produce EPS on the reconstructed Man Rogosa Sharpe medium (MRS). As a result, the three strains yielded high EPS production (4.15 ± 0.5–11.86 ± 0.1 g/L) after 48hr of incubation. The specific spectra of EPSs were obtained by FT-IR and 1H NMR analysis. All EPSs had glucose as a sole sugar constituent indicating they were glucan. The highest molecular weight (Mw, 104 kDa) was recorded with EPS68FE and the highest melting point was found with EPS47FE. Bioactivities indicated that the EPSs manifested potent antibacterial activity, and two of them (EPS47FE and EPS68FE) possessed a powerful anticoagulant and fibrinolytic activity. The EPSs (10 mg/mL) showed high DPPH radical of 54.50 ± 0.2–68.90 ± 0.3% and also emulsifying activity of 53.33 ± 0.5–83.33 ± 0.3% after 48hr. In conclusion, the EPS47FE, and EPS68FE produced from probiotic Lactobacilli had unique bioactivities with great potential in biomedicine, pharmaceutics, and food industries.

Effect of the stirring speed in the in vitro activity of α-amylase

Amylases are one of the main enzymes used in industry for hydrolyzing starch molecules into simple sugar constituents, can be sourced from plants, animals and microorganisms. Starch converting α-amylase has applications in different industrial sectors, and an ongoing research topic is to improve processing conditions leading to enhanced enzymatic activity and lower processing costs. Surprisingly, there are basically no studies regarding the impact of stirring speed on α-amylase activity. In this work, the effect of stirring speed (0, 50, 250, 500, 1000 and 1500 rpm) on the hydrolysis of gelatinized corn starch dispersions (5 g starch dry basis/100 L) by pancreatic α-amylase (0.125 and 0.250 μg/mL) was studied. The analysis of the hydrolysis kinetics curves showed that relatively small stirring speeds had positive effect on the hydrolysis rate. This effect was likely caused by improvements in the mass transfer coefficient by virtue of increased flow velocities. However, the enzyme activity exhibited a negative trend for high stirring speeds. FTIR analysis of α-amylase subjected to stirring indicated that changes in the Amide I secondary structure might be behind the decreased hydrolysis at high stirring speeds. This short communication provides insights for enhancing the bio-conversion of starch by α-amylase via stirring speed mediation.

Microgravity Affects the Level of Matrix Polysaccharide 1,3:1,4-β-Glucans in Cell Walls of Rice Shoots by Increasing the Expression Level of a Gene Involved in Their Breakdown.

The plant cell wall provides each cell with structural support and mechanical strength, and thus, it plays an important role in supporting the plant body against the gravitational force. We investigated the effects of microgravity on the composition of cell wall polysaccharides and on the expression levels of genes involved in cell wall metabolism using rice shoots cultivated under artificial 1 g and microgravity conditions on the International Space Station. The bulk amount of the cell wall obtained from microgravity-grown shoots was comparable with that from 1 g-grown shoots. However, the analysis of sugar constituents of matrix polysaccharides showed that microgravity specifically reduced the amount of glucose (Glc)-containing polysaccharides such as 1,3:1,4-β-glucans, in shoot cell walls. The expression level of a gene for endo-1,3:1,4-β-glucanase, which hydrolyzes 1,3:1,4-β-glucans, largely increased under microgravity conditions. However, the expression levels of genes involved in the biosynthesis of 1,3:1,4-β-glucans were almost the same under both gravity conditions. On the contrary, microgravity scarcely affected the level and the metabolism of arabinoxylans. These results suggest that a microgravity environment promotes the breakdown of 1,3:1,4-β-glucans, which, in turn, causes the reduced level of these polysaccharides in growing rice shoots. Changes in 1,3:1,4-β-glucan level may be involved in the modification of mechanical properties of cell walls under microgravity conditions in space.

Solid-State Fermentation of Cassava Roots Using Cellulolytic-Type Alkaliphilic Bacillus spp. Cultures to Modify the Cell Walls and Assist Starch Release.

To improve cassava starch extraction by wet milling, solid-state fermentation of ground roots using cellulolytic-type alkaliphilic Bacilli spp., Bacillus akibai, B. cellulosilyticus and B. hemicellulosilyticus was investigated. Enzyme assay and scanning electron microscopy indicated that Bacillus spp. production of extracellular cellulase and polygalacturonase caused the formation of micropores through the root parenchyma cell walls and exposed the embedded cellulosic network. Gas chromatography data of the cell wall constituent sugars remaining after fermentation and Fourier transform infrared data indicated that the Bacillus treatments reduced the levels of pectin and, hemicellulose and to lesser extent cellulose. Wide-angle X-ray scattering data indicated that the Bacillus spp. cell wall degrading enzymes had partially hydrolysed the amorphous fractions of the cell wall polysaccharides. All the Bacillus spp. treatments improved starch extraction by 17-23% compared to fermentation with endogenous microflora. B. cellulosilyticus was most effective in disintegration of large root particles and as result, released marginally the most starch, probably due to it having the highest cellulase activity. Solid-state fermentation using cellulolytic-type Bacillus spp. is, therefore, promising to technology to improve the efficiency of cassava wet milling cell wall disintegration and consequent starch yield without use of commercial cell wall degrading enzymes or polluting chemicals.

The molecular weight of ulvan affects the in vitro inflammatory response of a murine macrophage

Ulvan, a sulfated polysaccharide extracted from the green seaweed genus Ulva, has bioactive properties including an immunomodulating capacity. The immunomodulatory capacity of ulvan from Ulva ohnoi, however, has not been assessed in detail. We depolymerised purified ulvan from U. ohnoi to obtain a range of molecular weight fractions (Mw 7, 9, 13, 21, 209 kDa), which were characterised by constituent sugar analysis, SEC-MALLS, and NMR. Ulvan fractions contained 48.8–54.7 mol% rhamnose, 32.5–35.9 mol% glucuronic acid, 4.5–7.3 mol% iduronic acid, and 3.3–5.6 mol% xylose. 1H and 13C NMR was consistent with hydrolysis occurring at the anomeric centre without further modification to the oligosaccharide structure. The in vitro immunomodulatory effect of ulvan fractions was quantified by measuring levels of inflammatory-mediating signalling molecules released from LPS-stimulated RAW264.7 murine macrophages. All ulvan fractions showed no toxicity on RAW264.7 cells at concentrations below 100 μg mL−1 over 48 h. Secreted interleukin-10 and prostaglandin E2 demonstrated an anti-inflammatory effect by higher molecular weight ulvan fractions at 100 μg mL−1. To a lesser extent, these fractions also enhanced the LPS-induced inflammation through minor increases of IL-1β and IL-6. This study confirms that ulvan from U. ohnoi has a mild in vitro immunomodulatory effect.

The ptsG Gene Encoding the Major Glucose Transporter of Bacillus cereus C1L Participates in Root Colonization and Beneficial Metabolite Production to Induce Plant Systemic Disease Resistance.

Rhizosphere interactions between microorganisms and plants have great influence on plant health. Bacillus cereus C1L, an induced systemic resistance (ISR)-eliciting rhizobacterium from Lilium formosanum, can protect monocot and dicot plants from disease challenges. To identify the ISR-involved bacterial genes, the systemic protection effect of transposon-tagged mutants of B. cereus C1L against southern corn leaf blight (SCLB) was surveyed, and a mutant of the ptsG gene encoding glucose-specific permease of the phosphotransferase system was severely impaired in the abilities of disease suppression and root colonization. The ptsG mutant lost the preferential utilization of glucose and showed reduction of glucose-assisted growth in minimal medium. A promoter-based reporter assay revealed that ptsG expression could be activated by certain sugar constituents of maize root exudates, among which B. cereus C1L exhibited the highest chemotactic response toward glucose, whereas neither of them could attract the ptsG mutant. Additionally, ptsG deficiency almost completely abolished glucose uptake of B. cereus C1L. Metabolite analysis indicated that the lack of ptsG undermined glucose-induced accumulation of acetoin and 2,3-butanediol in B. cereus C1L, both eliciting maize ISR against SCLB. Pretreatments with B. cereus C1L, ptsG mutant, acetoin, and 2,3-butanediol enhanced defense-related reactive oxygen species accumulation and callose deposition at different levels that were positively correlated to their ISR-eliciting activities. Thus, glucose uptake-mediating ptsG participates in ISR elicitation by endowing B. cereus C1L with the full capacities for root colonization and beneficial glucose metabolite production, providing a clue regarding how ISR-mediating rhizobacteria create a mutually beneficial relationship with various plant species.

Utilization of Complex Pectic Polysaccharides from New Zealand Plants (Tetragonia tetragonioides and Corynocarpus laevigatus) by Gut Bacteroides Species.

Pectic polysaccharides from New Zealand (NZ) spinach (Tetragonia tetragonioides) and karaka berries (Corynocarpus laevigatus) were extracted and analyzed. NZ spinach polysaccharides comprised mostly homogalacturonan (64.4%) and rhamnogalacturonan I (5.8%), with side chains of arabinan (8.1%), galactan (2.2%), and type II arabinogalactan (7.1%); karaka berry polysaccharides comprised homogalacturonan (21.8%) and rhamnogalacturonan I (10.0%), with greater proportions of side chains (arabinan, 15.6%; galactan, 23.8%; and type II arabinogalactan, 19.3%). Screening of gut commensal Bacteroides showed that six were able to grow on the NZ spinach extract, while five were able to grow on the karaka berry extract. Analysis of the polysaccharides remaining after fermentation, by size-exclusion chromatography and constituent sugar analysis, showed that the Bacteroides species that grew on these two substrates showed preferences for the different pectic polysaccharide types. Our data suggest that, to completely degrade and utilize the complex pectin structures found in plants, members of Bacteroides and other bowel bacteria work as metabolic consortia.

Extracellular polysaccharide produced by Chlorella vulgaris – Chemical characterization and anti-asthmatic profile

Microalgae are the lowest plant organisms producing a wide range of metabolites that make them interesting organisms for industrial applications. Cultivation of green microalgal species Chlorella vulgaris resulted a significant production of extracellular polysaccharide (EPS). Preliminary chemico-spectroscopic studies on EPS revealed its molecular profile, a complex primary structure consisting of six monosaccharide units occurring in both furano and pyrano forms, a high sugar binding variability and the presence of partially methylated derivatives of some sugar constituents. Biological activity tests showed that EPS caused significant bronchodilatory, anti-inflammatory and antitussive effects in test animals. Chlorella EPS appears to be a promising agent for the prevention of chronic airway inflammation, which is the basic pathogenic mechanism of many respiratory diseases, including bronchial asthma.

Biorefinery processes for the valorization of Miscanthus polysaccharides: from constituent sugars to platform chemicals

A biorefinery scheme was proposed for manufacturing platform chemicals (furfural, denoted F, and 5-hydroxymethylfurfural, denoted HMF) from Miscanthus polysaccharides (including hemicelluloses and cellulose). The feedstock was first subjected to hydrothermal processing, which caused an extensive hemicellulose solubilization, yielding solids enriched in cellulose and aqueous solutions rich in saccharides. The acidic processing of the aqueous solutions in the presence of methyl isobutyl ketone (MIBK), which acted as an extracting agent, led to the formation and the in situ separation of F from pentoses at high molar yields (up to 78%). Moreover, HMF and levulinic acid were obtained from the hexoses released from the feedstock.The cellulose-enriched solids from hydrothermal processing were used as a substrate for HMF manufacture, employing a combination of enzymatic and chemical treatments. The enzymatic hydrolysis yielded glucose (in concentration up to 59 g /L), which was enzymatically isomerized into fructose in the presence of sodium tetraborate at yields up to 80%. Acidic treatments of the resulting reaction media at low temperature (134 °C) in the presence of H2SO4 enabled the formation of HMF at yields about 49%. Under the assayed conditions, glucose remained practically unaltered, facilitating its reutilization in the isomerization stage.

Industrial and Medical Material Applications of a Mega-polysaccharide Derived from Cyanobacteria

Polysaccharides (PS) are one form of biomass occurring in great abundance on earth and are promising organic material alternatives to petroleum-based ones. We have focused on PS produced by cyanobacteria. Aphanothece sacrum, which is a freshwater unicellular cyanobacterium, produces large amounts PS as a main component of the extracellular matrix. We successfully extracted the PS sacran from A. sacrum biomaterials and demonstrated that sacran contains carboxyls and sulfate groups. Furthermore, the constituent sugars of the sacran extracted were determined to be fucose, rhamnose, xylose, arabinose, mannose, glucose, galactose, glucuronic acid, galacturonic acid, and galactosamine. The sequence of sacran is still under investigation. In addition, we confirmed that the sacran was a supergiant with a high absolute molecular weight of 2.35×107 g/mol. Sacran shows a self-orienting behavior in dilute solution at a concentration range over 0.25 wt% to form a liquid crystalline structure. Using this property, it is possible to prepare a sacran cast film with an orientation structure, especially swelling in the thickness direction, to form anisotropic hydrogels. The anisotropy and degree of swelling of the hydrogels could be controlled by varying the heating temperature of the sacran cast file. Furthermore, sacran could be combined successfully with rayon as new fiber materials, and the sacran-rayon complex materials showed increased water absorption compared with the original rayon. This article introduces various applications of sacran in the industrial and medical fields.

Biotoxicity assessment and lignocellulosic structural changes of phosphoric acid pre-treated young coconut husk hydrolysate for biohydrogen production

Major sugar constituents in young coconut husk were found to be glucans (0.30 g/g husk), while xylans were 0.10 g/g husk. Pre-treatments were carried out using phosphoric acid with dried coconut husk powder under steam heating. The effect of phosphoric acid on coconut husk hydrolysis was observed using acid concentrations of 0%, 1%, 5% and 10% (v/v). Soluble sugar concentration in hydrolysate was increasing proportional to acid concentration, as the total recovered solid decreases. FTIR and XRD analysis showed that acid hydrolysis led to the disruption of internal chemical bonds, causing coconut husk structural sugars to be released into the hydrolysate. Highest soluble sugar concentration, 29.9 g/L with a total suspended solid of 75.1 g/L, was obtained when the coconut husk was pre-treated with 10% phosphoric acid, and can be utilised for biohydrogen fermentation. Biotoxicity testing of the hydrolysates shows that half-maximal inhibition concentration of phosphoric acid was around 4.41% for a 24-h incubation and 3.80% for a 96-h incubation.

Near-Infrared Hyperspectral Imaging Rapidly Detects the Decay of Postharvest Strawberry Based on Water-Soluble Sugar Analysis

This paper presents a novel strategy to detect the fungal decay in strawberry using reflectance near-infrared hyperspectral imaging (NIR-HSI, 1000–2500 nm). The variation of fructose, glucose, sucrose, and total water-soluble sugar (TWSS) content was analyzed using HPLC with a reference method during fungal infection in strawberry. The feasibility of quantifying sugar constituents relevant to the different stages of decay in strawberry was evaluated using NIR-HSI with key wavelengths selected via successive projection algorithm. The results showed that the predicted performance of TWSS content was acceptable within 0.807 for Rp2 and 2.603 for RPD, respectively. Five to seven key wavelengths were obtained based on sugar constituents, and excellent performance for classification accuracy among the three stages of decay was 89.4 to 95.4% for calibration and 87.0 to 94.4% for prediction, respectively. This rapid approach provides a new strategy for the selection of key wavelengths to detect the decay and sugar constituents in strawberries.

Effects of Hops (<i>Humulus lupulus</i> L.) Beta-Acids on Short Chain Fatty Acid Production from Complex Carbohydrates by Rumen Microbiota

The aim of this experiment was to determine the effects of beta-acids, prenylated phenolic compounds from the hops plant, on fermentation of individual carbohydrates by rumen microorganisms. Mixed, uncultivated rumen microbiota was harvested from rumen fistulated steers and washed to make cell suspensions. The suspensions were used to inoculate media with a glucan, fructan or constituent sugar, and fermentation was evaluated by production of short-chain fatty acids (SCFA). Hops beta-acid (30 ppm) was not universally inhibitory, but each of the SCFA (acetate, propionate or butyrate) was decreased (P < 0.05) in one or more of each cellulose or starch tested. The fermentation of sugars and fructans (short- or long-chain inulins) was not impacted by the phytochemicals. Previous results have shown that hops and hops extracts had the beneficial effects of reducing rumen ammonia and methane. The current results indicate that both starch and cellulose fermentation could be impacted. Because cellulose fermentation is nutritionally important on forage-based diets, hops phytochemicals might have more utility in cereal grain-based rations.

Characterization of Polysaccharides from Feijoa Fruits ( Acca sellowiana Berg.) and Their Utilization as Growth Substrates by Gut Commensal Bacteroides Species.

Polysaccharides from feijoa fruit were extracted and analyzed; the composition of these polysaccharides conforms to those typically found in the primary cell walls of eudicotyledons. The two major polysaccharide extracts consisted of mainly pectic polysaccharides and hemicellulosic polysaccharides [xyloglucan (77%) and arabinoxylan (16%)]. A collection of commensal Bacteroides species was screened for growth in culture using these polysaccharide preparations and placed into five categories based on their preference for each substrate. Most of the species tested could utilize the pectic polysaccharides, but growth on the hemicellulose was more limited. Constituent sugar and glycosyl linkage analysis showed that species that grew on the hemicellulose fraction showed differences in their preference for the two polysaccharides in this preparation. Our data demonstrate that the members of the genus Bacteroides show differential hydrolysis of pectic polysaccharides, xyloglucan, and arabinoxylan, which might influence the structure and metabolic activities of the microbiota in the human gut.

Molecular structures, chemical properties and biological activities of polysaccharide from Smilax glabra rhizome

The water-soluble crude polysaccharides, extracted from the rhizome of Smilax glabra, were fractionated using an anion exchange chromatography, yielding two fractions, F1 and F2. The crude and fractions (F1 and F2) mainly consisted of carbohydrates (66.7%–91.1%), proteins (7.30%–23.9%) and minor amount of sulfates (1.60%–9.40%). Glucose was the major monosaccharide unit of the polysaccharides with different levels of sugar constituents including galactose, arabinose, rhamnose and mannose. The molecular weight (Mw) of crude and fractions ranged from 32,102–6.3 × 103 g/mol. The crude and fractions could stimulate RAW264.7 cells to release nitric oxide and cytokines via up-regulation of their mRNA expression by the activation of NF-κB and MAPKs pathways. The related pattern recognition receptors (PRRs) on the surface of the cells appeared to be TLR2 and CR3. The GC–MS analysis revealed that the main backbone of the most immune-enhancing F2 was (1 → 4)-linked glucose and galactose chain with minor linkages of (1 → 6)-galactose, (1 → 3)-mannose, (1 → 2)-rhamnose and (1 → 5)-arabinose with some branches at C-3 and C-4 rhamnose, or C-6 galactose.