Water-insoluble Polysaccharides Research Articles

Study on the physicochemical properties and gut microbiota regulation of Poria cocos pachyman treated by ball milling

The effect of ball milling on the physicochemical properties and gut microbiota regulation of Poria cocos pachyman (PAC) was investigated. Ball milling reduced the particle size of PAC from 102 μm to 25.19 μm after 12 h, resulting in increasing particle uniformity. Scanning electron microscopy (SEM) revealed surface roughening and fragmentation of PAC after ball milling. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) indicated reduced crystallinity and increased hydroxyl group exposure in ball-milled PAC (BMP). Thermogravimetric analysis (TGA) showed decreased thermal stability in BMP. The optimal ball milled time was 7 h. Moisture contents in PAC and BMP-7 h were 10.30 ± 0.47 % and 10.72 ± 0.12 %, and carbohydrate contents were 81.02 ± 2.27 % and 74.54 ± 1.46 %. In vivo studies on mice demonstrated that both PAC and BMP-7 h increased diversity and reshaped the composition of gut microbiota, with BMP-7 h showing a more pronounced effect. BMP-7 h reduced the Firmicutes/Bacteroidetes ratio, and raised the abundance of Bacteroides, suggesting enhanced prebiotic potential. These findings highlight the role of ball milling in improving the physicochemical properties and prebiotic potential of water-insoluble polysaccharides and provide a theoretical basis for its broader application in the food and biopharmaceutical industries.

Germline β−1,3-glucan deposits are required for female gametogenesis in Arabidopsis thaliana

Correct regulation of intercellular communication is a fundamental requirement for cell differentiation. In Arabidopsis thaliana, the female germline differentiates from a single somatic ovule cell that becomes encased in β−1,3-glucan, a water insoluble polysaccharide implicated in limiting pathogen invasion, regulating intercellular trafficking in roots, and promoting pollen development. Whether β−1,3-glucan facilitates germline isolation and development has remained contentious, since limited evidence is available to support a functional role. Here, transcriptional profiling of adjoining germline and somatic cells revealed differences in gene expression related to β−1,3-glucan metabolism and signalling through intercellular channels (plasmodesmata). Dominant expression of a β−1,3-glucanase in the female germline transiently perturbed β−1,3-glucan deposits, allowed intercellular movement of tracer molecules, and led to changes in germline gene expression and histone marks, eventually leading to termination of germline development. Our findings indicate that germline β−1,3-glucan fulfils a functional role in the ovule by insulating the primary germline cell, and thereby determines the success of downstream female gametogenesis.

Metabolomic differences between non-hydrothermal treated water-soluble (WSPs) and hydrothermally treated water-insoluble (WIPs) Maitake polysaccharides fermented by Lactobacillus acidophilus and L. plantarum

Bacterial Metabolite through a fermentation process is a growing trend and a promising alternative for use as functional components. Non-hydrothermal water-soluble (WSPs) and hydrothermally treated water-insoluble (WIPs) Maitake polysaccharides were fermented with Lactobacillus acidophilus (LA) and Lactobacillus plantarum (LP). Chemical composition analysis indicated that Maitake polysaccharides contained 58.22 ± 1.35 % total sugar and 31.46 % β-glucan, essential for metabolites production. 6-glucanase was used to degrade the WIPs, and hydrothermally treated WIP fibers exhibited smooth microstructure. Hence, the LA and LP bacteria investigated the potential fermented metabolic activities and differences between WSPs(Sp1)and WIP(Sp3) Maitake polysaccharides using LC-MS, and 887 metabolites were identified. Using Venn, Partial least squares discriminant analysis (PLS-DA), VIP Metabolites, and other multivariate statistical analysis methods, metabolites were expressed differently in all samples. Due to hydrothermal processing, WIP induced the highest growth of LA and LP, with an abundance of isocitrate metabolites. Furthermore, 50 metabolite correlations were identified, leading to the classification of 6 distinct metabolic groups. Thus, the study offers the initial comprehensive analysis of metabolites in Lactobacillus-fermented Maitake polysaccharides, aiding in understanding its metabolic interactions and facilitating progress in food engineering research.

Structural variety of glucans from Ganoderma lucidum fruiting bodies

Ganoderma lucidum, widely used in traditional medicine, has several biological properties. Polysaccharides, mainly glucans, are known as one of its main bioactive compounds. Consequently, the achievement and chemical investigation of such molecules are of pharmaceutical interest. Herein, we obtained water-insoluble and water-soluble polysaccharides from G. lucidum by alkaline extraction. Fractionation process yielded three fractions (GLC-1, GLC-2, and GLC-3). All samples showed to be composed mainly of glucans. GLC-1 is a linear (1 → 3)-linked β-glucan; GLC-2 is a mixture of three different linear polysaccharides: (1 → 3)-β-glucan, (1 → 3)-α-glucan, and (1 → 4)-α-mannan; while GLC-3 is a branched β-glucan with a (1 → 4)-linked main chain, which is branched at O-3 or O-6 by (1 → 3)- or (1 → 6)-linked side chains. This research reports the variability of glucans in Ganoderma lucidum fruiting bodies and applicable methodologies to obtain such molecules. These polysaccharides can be further applied in biological studies aiming to investigate how their chemical differences may affect their biological properties.

Chitin quantitation (as glucosamine) in food raw materials by spectrophotometry

Chitin is a water insoluble nitrogen-containing polysaccharide made from N-acetyl-D-glucosamine containing β-(1→4)-linkages. In food, chitin is considered as a source of fiber with prebiotic properties to gut microflora. Chitin content varies widely in nature from 1% (yeasts) up to 64% (butterfly cuticles) and is mostly found in filamentous or mushroom forming fungi, insects and crustaceans. This spectrophotometric method is suitable for chitin quantitation (reported as glucosamine) in food raw materials like insects (mealworm larvae, crickets), shrimps, mushrooms and fungi in a research (non-routine) laboratory. To remove interferences, the sample is defatted (Soxhlet) prior to acid hydrolysis in 6 M HCl. The color complex is developed after the addition of Katano's reagent (a mix of 0.05 mol/L sodium metasilicate, 0.6 mol/L sodium molybdate, 30% dimethyl sulfoxide and 1.42 mol/L acetic acid) at 70 °C for 30 min and measured at 750 nm against blank. A five-point linear calibration (5–100 µg/mL) is used. Limit of detection is 3 µg GLCN/mL. The correlation (R2) with an HPLC method for chitin analysis is at least 0.93.•a reliable alternative to an HPLC method•does not require expensive equipment•deproteination by alkali is not necessary for most matrices - saves about 30% of time

Microbiome-friendly PS/PVP electrospun fibrous membrane with antibiofilm properties for dental engineering.

Dental caries is one of the most prevalent and biofilm-associated oral diseases in humans. Streptococcus mutans, with a high ability to form biofilms by adhering to hard surfaces, has been established as an important etiological agent for dental caries. Therefore, it is crucial to find a way to prevent the formation of cariogenic biofilm. Here, we report an electrospun fibrous membrane that could inhibit the adhesion and biofilm formation of S. mutans. Also, the polystyrene (PS)/polyvinyl pyrrolidone (PVP) electrospun fibrous membrane altered the 3D biofilm architecture and decreased water-insoluble extracellular polysaccharide production. Notably, the anti-adhesion mechanism which laid in Coulomb repulsion between the negatively charged PS/PVP electrospun fibrous membrane and S. mutans was detected by zeta potential. Furthermore, metagenomics sequencing analysis and CCK-8 assay indicated that PS/PVP electrospun fibrous membrane was microbiome-friendly and displayed no influence on the cell viability of human gingival epithelial cells and human oral keratinocytes. Moreover, an in vitro simulation experiment demonstrated that PS/PVP electrospun fibrous membrane could decrease colony-forming unit counts of S. mutans effectively, and PS/PVP electrospun fibrous membrane carrying calcium fluoride displayed better anti-adhesion ability than that of PS/PVP electrospun fibrous membrane alone. Collectively, this research showed that the PS/PVP electrospun fibrous membrane has potential applications in controlling and preventing dental caries.

Enzymatic hydrolysis of starch in electrochemically activated aqueous solution

In this work, the hydrolysis of starch in an enzyme solution was studied, where softened water or fractions of a metastable electrochemically activated aqueous solution (ECAS) were used as a solvent. Extracts obtained after hydrolysis of food starch grains were analyzed using optical density spectrometry of the sample and micro-weighing with a quartz resonator of the dry residue contained in an aqueous solution. It is shown that the enzyme solution on the reduced fraction of ECAS (catholyte) contains the least amount of extracted substances, but it contains the highest concentration of oligosaccharides. This fact may mean the presence of a more efficient cleavage by the enzyme of water-insoluble polysaccharides to low molecular weight derivatives in the medium of the electrolyte. As a result of this synergistic effect, a relatively high content of oligosaccharides is observed even at a low level of primary hydrolysis on the surface of the starch grain. This assumption was investigated on modified starch soluble in water. For the compared aqueous solutions of the enzyme preparation, which initially contain the same concentration of amylodextrins, faster hydrolysis is observed in the enzyme medium on softened water.

Fluoride-resistant Streptococcus mutans within cross-kingdom biofilms support Candida albicans growth under fluoride and attenuate the in vitro anti-caries effect of fluorine.

Fluoride-resistant Streptococcus mutans (S. mutans) might affect the ecological balance of biofilms in the presence of fluoride. We used a S. mutans and Candida albicans (C. albicans) cross-kingdom biofilm model to investigate whether fluoride-resistant S. mutans in biofilms would support C. albicans growth under fluoride stress and attenuate the in vitro anti-caries effect of fluorine. The impact of fluoride-resistant S. mutans on formation of cross-kingdom biofilms by S. mutans and C. albicans in the presence of fluoride was investigated in vitro using the crystal violet staining assay. Biofilm constitution was determined using colony-forming unit (CFU) counts and fluorescent in situ hybridization (FISH). Extracellular polysaccharide (EPS) generation in biofilms was determined by EPS/bacterial dying and water-insoluble polysaccharide detection. Acid production and demineralization were monitored using pH, lactic acid content, and transversal microradiography (TMR). The gene expression of microorganisms in the cross-kingdom biofilm was measured using qRT-PCR. Our results showed that both C. albicans and fluoride-resistant S. mutans grew vigorously, forming robust cross-kingdom biofilms, even in the presence of sodium fluoride (NaF). Moreover, fluoride-resistant S. mutans-containing cross-kingdom biofilms had considerable cariogenic potential for EPS synthesis, acid production, and demineralization ability in the presence of NaF than fluoride-sensitive S. mutans-containing biofilms. Furthermore, the gene expression of microorganisms in the two cross-kingdom biofilms changed dissimilarly in the presence of NaF. In summary, fluoride-resistant S. mutans in cross-kingdom biofilms supported C. albicans growth under fluoride and might attenuate the anti-caries potential of fluorine by maintaining robust cross-kingdom biofilm formation and cariogenic virulence expression in vitro in the presence of NaF.

Development of hyaluronic acid based polysaccharide-protein composite edible coatings for preservation of strawberry fruit

With the growing demand for extending the shelf-life of perishable goods such as fruits and vegetables, there is continued interest towards the development of edible coatings derived from natural sources. To avoid rapid dissolution, water insoluble polysaccharide such as chitosan has been widely explored. In this work, we developed robust hyaluronic acid-based edible polysaccharide-protein coatings by combining it (hyaluronic acid) with chitosan and gelatin to introduce additional antioxidant properties. This work is the first example of using hyaluronic acid in edible coatings for fruit preservation. The effect of developed edible composite coatings on the quality of coated strawberries was investigated over a 15 day storage period with 3-day examination intervals. The obtained results revealed hyaluronic acid dose-dependent improvement in intrinsic properties of coated strawberries including weight loss, pH, titratable acidity (TA) and total solids content (TSS). Furthermore, the inclusion of hyaluronic acid significantly enhanced the antioxidant properties of developed edible coatings as measured using total phenolic content, change in ascorbic acid content and DPPH assay prolonging the shelf-life of coated strawberries.

Investigation of the transport and metabolic patterns of oil-displacing bacterium FY-07-G in the microcosm model using X-CT technology.

Microbially Enhanced Oil Recovery (MEOR) is dedicated to enhancing oil recovery by harnessing microbial metabolic activities and their byproducts within reservoir rocks and fluids. Therefore, the investigation of microbial mobility and their extensive distribution within crude oil is of paramount importance in MEOR. While microscale models have been valuable for studying bacterial strain behavior in reservoirs, they are typically limited to 2D representations of porous media, making them inadequate for simulating actual reservoir conditions. Consequently, there is a critical need for 3D models and dependable visualization methods to observe bacterial transport and metabolism within these complex reservoir environments. Bacterial cellulose (bc) is a water-insoluble polysaccharide produced by bacteria that exhibits biocompatibility and biodegradability. It holds significant potential for applications in the field of MEOR as an effective means for selective plugging and spill prevention during oil displacement processes. Conditionally cellulose-producing strain, FY-07-G, with green fluorescent labeling, was engineered for enhanced oil recovery. 3D micro-visualization model was constructed to directly observe the metabolic activities of the target bacterial strain within porous media and to assess the plugging interactions between cellulose and the medium. Additionally, X-ray computed tomography (X-CT) technology was employed for a comprehensive analysis of the transport patterns of the target strain in oil reservoirs with varying permeabilities. The results indicated that FY-07-G, as a microorganism employing biopolymer-based plugging principles to enhance oil recovery, selectively targets and seals regions characterized by lower permeability and smaller pore spaces. This work provided valuable insights into the transport and metabolic behavior of MEOR strains and tackled the limitation of 2D models in faithfully replicating oil reservoir conditions, offering essential theoretical guidance and insights for the further application of oil-displacing bacterial strains in MEOR processes.

Effects of synergistic Fenton-microwave treatment on the antioxidant stress of soluble polysaccharides and the physicochemical properties of insoluble polysaccharides from Gelidium amansii

In this study, we individually obtained crude Gelidium amansii water-soluble polysaccharides and water-insoluble polysaccharides (GAIPs) using an improved Fenton–microwave synergistic treatment. The former were purified by alcohol precipitation and deproteinization to obtain Gelidium amansii water-soluble polysaccharides (GASPs), and their effects on the oxidative stress resistance of Caenorhabditis elegans were investigated. GAIPs were studied for their physicochemical properties, including hydration characteristics, adsorption, and cation-exchange capacity. The results showed that compared with the negative control, 1.0 mg/mL GASPs significantly upregulated (>1.70-fold) the expression of antioxidant-related genes, such as daf-16, sir-2.1, and skn-1 (p < 0.05), which prolonged the mean survival time and increased the mean number of head bobbing (p < 0.05). The hydration characteristics and oil-holding capacity of GAIPs were lower than those of G. amansii powder (GAP) and G. amansii filtrate residue (GADP). However, the adsorption capacity of GAIPs for cholesterol (pH 7.0) and sodium cholate and the cation-exchange capacity were significantly better than those of GAP (5.17, 13.16 & 1.63 times, p < 0.05) and GADP (8.42, 6.39, & 2.05 times, p < 0.05). To conclude, the synergistic Fenton–microwave treatment contributed to the increase in the oxidative stress resistance of GASPs and improved the adsorption capacity and cation-exchange capacity of GAIPs.

Physico-mechanical and antimicrobial properties of an elastomeric ligature coated with reduced nanographene oxide-nano curcumin subjected to dual-modal photodynamic and photothermal inactivation against Streptococcus mutans biofilms

BackgroundWhite spot lesions (WSLs) are a common side effect of fixed orthodontic treatment. Streptococcus mutans is the primary causative agent of WSLs and dental caries on the teeth during treatment. According to the unique features of reduced graphene oxide-nano curcumin (rGO-nCur), this study aimed to investigate the mechanical properties and antimicrobial potency of rGO-nCur coated orthodontic elastomeric ligatures as a novel coating composite following dual-modal photodynamic inactivation (PDI) and photothermal inactivation (PTI) against S. mutans biofilms. MethodsAfter confirmation of rGO-nCur synthesis and coating elastomeric ligatures with different concentration levels of 1.25, 2.5, 5, 7.5, and 10 % of rGO-nCur, tensile strength, force decay, extension to tensile strength, and contact angle of the coated elastomeric ligatures were measured using universal testing machine and sessile drop method, respectively. To investigate the mechanism through which irradiated rGO-nCur can inhibit the formation of S. mutans biofilms, intracellular reactive oxygen species (ROS) generation, and increase in temperature of rGO-nCur solutions under the 450 and 980 nm laser irradiation, respectively, were measured. The anti-biofilm activity and inhibition of water-insoluble extracellular polysaccharide (EPS) production ability of irradiated rGO-nCur coated elastomeric ligatures using a 450 nm diode laser (195 J/cm2), a 980 nm diode laser (195 J/cm2), and a combination of both (78 J/cm2 of irradiation from each one) (i.e., PDI, PTI, and dual-modal PDI/PTI, respectively) were determined. Also, the expression of virulence genes involved in biofilm formation (comDE, gtfD, and smuT) was assessed by quantitative real-time polymerase chain reaction (RT-qPCR) following the mentioned treatment. One-way ANOVA test and Tukey post-hoc test at a p-value equal to/or less than 0.05 were used to analyze the obtained data. ResultsThe synthesis of GO nano-sheets in a layered structure with a thickness of 0.76 nm was confirmed by AFM analysis. FESEM showed that the exfoliated sheet of synthesized GO had several micrometers in lateral size. DLS revealed that the mean particle size and density index of synthesized nCur were 57.47 ± 2.14 nm and 10 % respectively. In DLS analysis, rGO-nCur showed more positive surface charge (24 mV) than the nano-sheets of GO. FESEM confirmed the coating of rGO-nCur on elastomeric ligatures. ANOVA revealed that tensile strength of 1.25, 2.5, and 5 % rGO-nCur coated elastomeric ligatures were not decreased statistically significantly (P > 0.05). Mean tensile strength and recorded force of 7.5 and 10 % rGO-nCur coated elastomeric ligatures decreased significantly after 14 days’ immersion in the artificial saliva (P < 0.05). On the 28th day of the study, the mean of the tensile strength of elastomeric ligatures coated with 10 % rGO-nCur (13.03 ± 0.10 N) was recorded as 55.90 % of the initial tensile strength (23.31 ± 0.41 N in uncoated elastomeric ligatures), while the mean tensile strength of elastomeric ligatures coated with 7.5 % rGO-nCur (16.01 ± 0.10 N) was measured as 68.94 % of the initial tensile strength (23.22 ± 0.09 N in uncoated elastomeric ligatures). When comparing the coated elastomeric ligatures at 7.5 % and 10 % to the original uncoated elastomeric ligatures at similar time intervals, statistically significant decreases in extension to tensile strength (0.42 to 0.71 mm or 3.02 to 5.05 %; all P < 0.05) were observed. The largest contact angle was measured in elastomeric ligatures coated by 10 % rGO-nCur followed by 7.5 and 5 % rGO-nCur (128 ± 2.19°, 117 ± 2.23°, and 99 ± 1.83°; respectively). The results revealed a rise of 6.4-fold in intracellular ROS and an 11.2 °C increase in the temperature of rGO-nCur solutions following the 450 nm and 980 nm laser irradiation, respectively. The 5 % rGO-nCur coated elastomeric ligature mediated dual-modal PDI/PTI showed the most inhibition of the biofilm formation of S. mutans by 83.62 % (P = 0.00). Significant reductions in water-insoluble EPS were detected in biofilm cultures of S. mutans on 1.25 % rGO-nCur coated elastomeric ligatures following irradiation with dual waves of the 450 nm and 980 nm diode lasers (i.e., dual-modal PDI/PTI; 96.17 %; P = 0.00). The expression levels of comDE, gtfD, and smuT virulence genes were significantly downregulated (7.52-, 13.92-, and 8.23-fold, respectively) in the biofilm cultures of S. mutans on 1.25 % rGO-nCur coated elastomeric ligatures following dual-modal PDI/PTI in comparison with biofilm cultures on non-coated elastomeric ligatures. Conclusion5 % rGO-nCur coated elastomeric ligatures following irradiation with dual waves of the 450 and 980 nm diode lasers (dual-modal PDI/PTI), without adverse effects on the physico-mechanical properties of elastomeric ligatures, can be used to inhibit the formation of S. mutans biofilms on the coated elastomeric ligatures around orthodontic brackets.

Structure and emulsifying properties of unprecedent glucomannan oligo- and polysaccharides from Amazonia Acrocomia aculeata palm fruit

Acrocomia aculeata fruit pulp contains oil (4.1–82.8 % fresh matter) and carbohydrates (6.6–98.0 % fresh matter). To date, only the oil fraction is valorized because very little is known about the nature of carbohydrates. This study explores new ways of adding value to this pulp by developing simple and efficient extraction processes for its carbohydrate components and characterizing their structure and physicochemical properties over two harvest periods. A water-soluble monosaccharide fraction F1 (solubility limit (SL): 98.5–99.3 g/L) (yield: 21 % dry pulp (DP)), a water-soluble polysaccharide fraction F2 (SL: 93.3–95.3 g/L) (yield: 26 % DP) and two additional water-insoluble polysaccharide fractions F3 and F4 (SL: <8 g/L) (yields: 10 and 19 % DP, respectively) were isolated. NMR structural characterizations of fraction F2 revealed it to be a linear glucomannan with β-(1 → 4) osidic linkages between d-Manp and d-Glcp residues. F2 is unique for its d-Manp/d-Glcp ratio of 3:1 and the position of its acetyl group (13–14 %, C-2 d-Manp). Finally, the polysaccharide showed a molecular weight (Mw) variation ranging from 8.2 × 104 to 1.1 × 103 Da over the two harvest periods, with remarkable emulsifying properties associated with a low Mw of F2 (stability >6 months, 1 % w/v in a water-in-oil emulsion).

The extraction, structure characterization and hydrogel construction of a water-insoluble β-glucan from Poria cocos

Most reported polysaccharides from Poria cocos (PCPs) in traditional Chinese medicine decoctions were water-soluble heteropolysaccharides while the water-insoluble PCPs were scarcely researched due to the poor water-solubility. In this study, a water-insoluble polysaccharide with high yield of 59%, and high purity with a glucan content of 98.8%, was isolated by diluted sodium hydroxide at low temperature and coded as PCPA. The chemical structure of PCPA was identified as a liner β-glucan with 1, 3-linked glycosidic bond by the fourier infrared spectrum (FT-IR), ion chromatography (ICP), gas chromatography and mass spectrometry (GC-MS), and nuclear magnetic resonance (NMR) measurements. Importantly, PCPA was successfully used to construct hydrogels (PCPA-Gs) with good thermal stability, water retention ability and swelling property through simple physical cross-linking, due to the abundance of hydroxyl groups on glucan chains. Moreover, the rheology analysis of PCPA-Gs showed a rapid transition between gel and sol as well as the shear-thinning property. The hydrogel developed in this study holds promise for applications in the food, pharmaceutical, and cosmetic fields.

Structural analysis of a water insoluble polysaccharide from pearl millet and evaluating its prebiotic activity

Epidemiological studies have shown an inverse correlation between dietary intake of prebiotics and the risk of chronic diseases. Pearl millet is a potential economic source to develop a new class of prebiotics in the form of its polysaccharide. In the present study, the chemical structure of a water insoluble homopolysaccharide (PMG), and its prebiotic properties were investigated. The structure of PMG was elucidated on the basis of total hydrolysis, methylation analysis, and 1D/2D NMR (1H, 13C, DEPT-135, HSQC, DQF-COSY, NOESY and ROESY) experiments. The results indicated that PMG was a glucan with an average molecular weight ~ 361 kDa having a backbone of (1 → 3) α-d-glucopyranosyl residues. Hydrolysis of PMG by salivary and pancreatic α amylase was 1.75 % ± 0.34 and 1.99 % ± 0.18 respectively. A positive prebiotic score of PMG with both L. acidophilus and L. brevis (0.446 ± 0.031 & 0.427 ± 0.016) hints towards its prebiotic potential. These observations suggest that PMG might be used as a potential prebiotic component in the food and pharmaceutical applications.

Acetylation in Ionic Liquids Dramatically Increases Yield in the Glycosyl Composition and Linkage Analysis of Insoluble and Acidic Polysaccharides.

Glycosyl composition and linkage analyses are important first steps toward understanding the structural diversity and biological importance of polysaccharides. Failure to fully solubilize samples prior to analysis results in the generation of incomplete and poor-quality composition and linkage data by gas chromatography-mass spectrometry (GC-MS). Acidic polysaccharides also do not give accurate linkage results, because they are poorly soluble in DMSO and tend to undergo β-elimination during permethylation. Ionic liquids can solubilize polysaccharides, improving their derivatization and extraction for analysis. We show that water-insoluble polysaccharides become much more amenable to chemical analysis by first acetylating them in an ionic liquid. Once acetylated, these polysaccharides, having been deprived of their intermolecular hydrogen bonds, are hydrolyzed more readily for glycosyl composition analysis or methylated more efficiently for glycosyl linkage analysis. Acetylation in an ionic liquid greatly improves composition analysis of insoluble polysaccharides when compared to analysis without acetylation, enabling complete composition determination of normally recalcitrant polysaccharides. We also present a protocol for uronic acid linkage analysis that incorporates this preacetylation step. This protocol produces partially methylated alditol acetate derivatives in high yield with minimal β-elimination and gives sensitive linkage results for acidic polysaccharides that more accurately reflect the structures being analyzed. We use important plant polysaccharides to show that the preacetylation step leads to superior results compared to traditional methodologies.

Water-Insoluble Polysaccharide Extracted from Poria cocos Alleviates Antibiotic-Associated Diarrhea Based on Regulating the Gut Microbiota in Mice.

Antibiotics are very effective in treating a variety of bacterial infections, while clinical overuse of antibiotics can lead to diseases such as antibiotic-associated diarrhea. Numerous studies have shown that natural polysaccharides can be used as prebiotics to alleviate antibiotic-associated diarrhea (AAD). Poria cocos is a medicinal and edible mushroom widely used for thousands of years in China, and our former study demonstrated that water-insoluble polysaccharide (PCY) has the potential prebiotic function. Therefore, we simulated the digestion and fermentation of PCY using feces from volunteers, and then administered it to C57BL/6 mice with AAD to study its effects on the gut microbiota and metabolites. The results indicated that PCY effectively alleviated the symptoms of AAD in mice, restored the intestinal barrier function, improved the content of short-chain fatty acids (SCFAs), decreased the level of inflammatory cytokines, and changed the structure of gut microbiota by increasing the relative abundance of norank_f__Muribaculaceae and unclassified_f__Lachnospiraceae, and decreasing that of Escherichia-Shigella, Staphylococcus and Acinetobacter. This study further demonstrated that PCY is an effective functional prebiotic for improving AAD disease, and provided a new avenue and insight for developing PCY as a functional food or prebiotic for alleviating gastrointestinal diseases.

Mutanase from Trichoderma harzianum inductively Produced by Mutan: Short-Term Treatment to Degrade Mature Streptococcus mutans Biofilm.

This study aimed to evaluate the disruptive effect of fungal mutanase against cariogenic biofilm after short-term treatment. For that, mature Streptococcus mutans biofilms (n = 9) were exposed to active or inactivated enzymes produced by Trichoderma harzianum for 1 min, two times per day. Biofilms were analyzed by amount of matrix water-insoluble polysaccharides, bacterial viability, acidogenicity, and morphology by scanning electron microscopy (SEM). The group treated with active enzymes (AE) had a significantly lower amount of insoluble polysaccharides (893.30 ± 293.69) when compared to the negative control group (NaCl, 2192.59 ± 361.96), yet no significant difference was found when comparing to the positive control group (CHX, 436.82 ± 151.07). Also, there was no significant effect on bacteria metabolism and viability (P-value < 0.05). Data generated by the quantitative analysis were confirmed through scanning electron microscopy images. Thus, fungal mutanase degraded the biofilm after a short-term treatment without interfering with bacterial viability and metabolism. Such findings offer insight to the development of routine oral care products containing this input.

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Herein, a single molecule detection technology based on glass nanopore is established to analyze xylan dissolved in ionic liquid. The nanopore detection technology shows the structural difference of heterogenous branched chain and homogeneous straight chain based on the single characteristic current blocking signal and statistical information, providing a research basis for the structural analysis of water insoluble polysaccharides. More details are discussed in the article by He et al. on page 1720—1726.image

Disaggregated Nano-Hydroxyapatite (DnHAP) with Inhibitory Effects on Biofilms and Demineralization

Nano-hydroxyapatite (nHAP) is considered a biocompatible agent that promotes the remineralization of dental hard tissue; however, its antibacterial efficacy is under scientific discussion. Therefore, this investigation aimed to specify the inhibitory effects of disaggregated nano-hydroxyapatite (DnHAP) on regrown biofilms and demineralization. Regrown biofilm models of single-species (Streptococcus mutans), dual-species (S. mutans and Candida albicans), and saliva-derived microcosm biofilms were established in vitro. Repeat treatment with DnHAP was applied to biofilms. The viability, lactic acid, biofilm structure, biomass, the inhibitory effect of demineralization, and virulence factors’ expression were determined. In addition, the biofilm microbial community was analyzed by 16S ribosomal RNA gene sequencing. DnHAP inhibited metabolism, lactic acid production, biomass, and water-insoluble polysaccharide production (P < 0.05) of regrown single/dual-species biofilms. Concerning the saliva-derived biofilms, samples treated with DnHAP showed lower biofilm metabolic activity without significant differences from samples treated with sterile deionized water (P > 0.05); in addition, saliva-derived biofilms treated with DnHAP exhibited lower lactic acid production (P < 0.05). The demineralization of bovine enamel was the lowest in the DnHAP group, as detected by transverse microradiography, and the lesion depth and volume decreased significantly (P < 0.05). The application of DnHAP did not change the diversity of regrown saliva-derived microcosm biofilms. In conclusion, this investigation showed that DnHAP could be a promising solution for the management of regrown biofilms to combat dental caries.