Microarray Analysis of Paramylon, Isolated from Euglena Gracilis EOD-1, and Its Effects on Lipid Metabolism in the Ileum and Liver in Diet-Induced Obese Mice.

We previously showed that supplementation of a high fat diet with paramylon (PM) reduces the postprandial glucose rise, serum total and LDL cholesterol levels, and abdominal fat accumulation in mice. The purpose of this study was to explore the underlying mechanism of PM using microarray analysis. Male mice (C57BL/BL strain) were fed an experimental diet (50% fat energy) containing 5% PM isolated from Euglena gracilis EOD-1 for 12 weeks. After confirming that PM had an improving effect on lipid metabolism, we assessed ileal and hepatic mRNA expression using DNA microarray and subsequent analysis by gene ontology (GO) classification and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. The results suggested that dietary supplementation with PM resulted in decreased abdominal fat accumulation and serum LDL cholesterol concentrations via suppression of the digestion and absorption pathway in the ileum and activation of the hepatic PPAR signaling pathway. Postprandial glucose rise was reduced in mice fed PM, whereas changes in the glucose metabolism pathway were not detected in GO classification and KEGG pathway analysis. PM intake might enhance serum secretory immunoglobulin A concentrations via promotion of the immunoglobulin production pathway in the ileum.

High level expression of a xyloglucanase from Rhizomucor miehei in Pichia pastoris for production of xyloglucan oligosaccharides and its application in yoghurt.

The xyloglucanase gene (RmXEG12A) from Rhizomucor miehei CAU432 was successfully expressed in Pichia pastoris. The highest xyloglucanase activity of 25,700 U mL-1 was secreted using high cell density fermentation. RmXEG12A was optimally active at pH 7.0 and 65 °C, respectively. The xyloglucanase exhibited the highest specific activity towards xyloglucan (7915.5 U mg-1). RmXEG12A was subjected to hydrolyze tamarind powder to produce xyloglucan oligosaccharides with the degree of polymerization (DP) 7-9. The hydrolysis ratio of xyloglucan in tamarind powder was 89.8%. Moreover, xyloglucan oligosaccharides (2.0%, w/w) improved the water holding capacity (WHC) of yoghurt by 1.1-fold and promoted the growth of Lactobacillus bulgaricus and Streptococcus thermophiles by 2.3 and 1.6-fold, respectively. Therefore, a suitable xyloglucanase for tamarind powder hydrolysis was expressed in P. pastoris at high level and xyloglucan oligosaccharides improved the quality of yoghurt.

Structure and immunomodulatory activity of a water-soluble α-glucan from Hirsutella sinensis mycelia.

Hirsutella sinensis, the anamorph of Ophiocordyceps sinensis (syn. Cordyceps sinensis), is a great substitute for precious and rare wild Cordyceps sinensis to effectively treat a variety of lung and kidney diseases. In this study, an α-glucan (named as HSWP-2a) was obtained by hot water extraction, DEAE-cellulose separation, and Sepharose CL-6B purification from H. sinensis mycelia. Different from known α-glucans, HSWP-2a is an α-(1 â†’ 4)-D-glucan that branched at O-6, O-3, or O-2 with a terminal 1-linked α-D-Glcp as side chain, with an average molecular weight of 870.70 kDa. Immunological tests showed that HSWP-2a could remarkably enhance the phagocytosis of macrophages and increase the production of NO, IL-1ß, IL-6, and TNF-α, via activating the p38, JNK, and NF-κB signaling pathways. Moreover, HSWP-2a could significantly promote splenic lymphocyte proliferation. Taken together, HSWP-2a may be potentially utilized as a natural immunomodulatory agent.

Effect of Intake of Food Hydrocolloids of Bacterial Origin on the Glycemic Response in Humans: Systematic Review and Narrative Synthesis.

Diabetes mellitus is a chronic condition characterized by increased blood glucose levels from dysfunctional carbohydrate metabolism. Dietary intervention can help to prevent and manage the disease. Food hydrocolloids have been shown to have favorable properties in relation to glycaemic regulation. However, the use of food hydrocolloids of bacterial origin to modulate glucose responses is much less explored than other types of hydrocolloids. We, therefore, carried out the first review examining the impact of intake of food hydrocolloids of bacterial origin (as a direct supplement or incorporated into foods) on glycemic response in humans. Fourteen studies met the inclusion criteria. They used either xanthan gum, pullulan, or dextran as interventions. There was a wide variation in the amount of hydrocolloid supplementation provided and methods of preparation. Postprandial blood glucose responses were reduced in half of the studies, particularly at higher intake levels and longer chain hydrocolloids. When xanthan gum was added to the cooking process of muffins and rice, a significant reduction in postprandial blood glucose was observed. The use of these hydrocolloids is potentially effective though more research is needed in this area.

Characterization of a nanoparticulate exopolysaccharide from Leuconostoc holzapfelii KM01 and its potential application in drug encapsulation.

Fermentation of Lactic Acid Bacteria (LAB) is considered to be a sustainable approach for polysaccharide production. Herein, exopolysaccharide (EPS)-producing LAB strain KM01 was isolated from Thai fermented dessert, Khao Mak, which was then identified as Leuconostoc holzapfelii. High-performance anion-exchange chromatography, nuclear magnetic resonance spectroscopy and Fourier-transform infrared spectroscopy suggested that the KM01 EPS comprises α-1,6-linked glucosides. The molecular weight of KM01 EPS was around 500 kDa, but it can form large aggregates formation (MW > 2000 kDa) in an aqueous solution, judged by transmission electron microscopy and dynamic light scattering to be around 150 nm in size. Furthermore, this KM01 EPS form highly viscous hydrogels at concentrations above 5% (w/v). The formation of hydrogels and nanoparticle of KM01 EPS was found to be reversible. Finally, the suitability of KM01 EPS for biomedical applications was demonstrated by its lack of cytotoxicity and its ability to form complexes with quercetin. Unlike the common α-1,6-linked dextran, KM01 EPS can enhance the solubility of quercetin significantly.

Heteropolysaccharides from S. cerevisiae show anti-adhesive properties against E. coli associated with Crohn's disease.

The Saccharomyces cerevisiae CNCM I-3856 was previously reported to strongly inhibit adherent-invasive Escherichia coli (AIEC) adhesion to intestinal epithelial cells in vitro and to favor AIEC elimination from the gut in a murine model of Crohn's disease in vivo. In order to identify which cell wall components of yeast are responsible for AIEC elimination, constituent polysaccharides of yeast were isolated and their anti-adhesive ability against AIEC adhesion in vitro was screened. A fraction containing mannan, ß-glucan and α-glucan extracted from yeast cell-walls was shown to inhibit 95% of AIEC adhesion in vitro and was thus identified as the strongest anti-adhesive yeast cell wall component. Furthermore, this mannan-glucan-containing fraction was shown to accelerate AIEC decolonization from gut in vivo. This fraction could be proposed as a treatment to eliminate AIEC bacteria in patients with Crohn's disease, a microbial trigger of intestinal inflammation.

A specific and bioactive polysaccharide marker for Cordyceps.

Cordyceps is one of the most expensive and widely used functional foods. But the authenticity is still a concern due to the lack of appropriate markers. By targeting polysaccharides, this study aimed to develop a specific, and bioactive marker for Cordyceps. Firstly, the results of screening tests of 250 samples by examining both genetic markers and polysaccharide profile showed that a unique polysaccharide fraction (named CCP) was particular to the caterpillar parts. Its potential as a marker was further demonstrated by its ability to induce NO and cytokine production in RAW 264.7 cells. CCP was characterized to be an α-1,4-glucan with a branch at C-6 by the conventional structure analyzing and de novo oligosaccharides sequencing. The content of CCP was closely correlated to the traditional classification criteria. Generally, CCP was a marker that simultaneously enables qualitative and quantitative analysis of Cordyceps.

Structure, size and aggregated morphology of a ß-D-glucan from Lignosus rhinocerotis as affected by ultrasound.

The effect of ultrasonic treatment on the structure, size and aggregated morphology of Lignosus rhinocerotis polysaccharide (LRP) was investigated. Ultrasonic treatment for 10 min has demonstrated to improve the aqueous solubility of LRP, leading to a uniform and narrow LRP particle size distribution. Meanwhile, short-time ultrasound was found to obviously decrease the molecular size parameters (Mw, Mn, z1/2, [η] and Rh) of LRP, and transform the hyperbranched LRP molecules into flexible and extended chains, which would reaggregate to form spherical aggregates under long-time ultrasonication. Additionally, Congo red experiment combined with CD analysis indicated the existence of triple helix structure in LRP, which was still retained after ultrasonic treatment. Furthermore, under short-time ultrasonication, the spherical aggregates with some branched chains in the native LRP solution could disaggregate and form triple helixes that could be further arranged to a dense network structure, but the untangled LRP chains would reaggregate after long-time ultrasonication. CHEMICAL COMPOUNDS STUDIED IN THIS ARTICLE: Congo red (PubChem CID: 11313); Sodium hydroxide (PubChem CID: 14798); Potassium bromide (PubChem CID: 253877).

In vitro immunomodulatory activity of water-soluble glucans from fresh and dried Longan (Dimocarpus longan Lour.).

Longan (Dimocarpus longan Lour.) is a seasonal tropical fruit used by Chinese medicine in both fresh and dried pulp forms. Their polysaccharides have been reported to have biological activity. However, their composition and immune activity have not yet been disclosed. To fulfil this aim, hot water-soluble polysaccharides of fresh and dried longan pulp were fractionated according to their molecular weight by ultrafiltration (10, 50, 100 kDa cut off). The main polysaccharides recovered were 1,6-linked glucans branched at O-3 (4-8%), O-2 (1%), O-2,4 (0.1%), and O-3,4 (0.1%). The drying process promotes the solubility of the polysaccharides. These glucans from fresh and dried longan pulp have immunomodulatory activity, shown by in vitro phagocytosis, NO, TNF-α, and IL-6 macrophages production assays. They showed also to inhibit the inflammatory response induced by LPS. The immunological activity of these glucans seems to have different responses dependent on their molecular weight, related to the immune regulatory pathways.

[Fungal Beta-glucans: Structure and Effect on Host Immune Responses].

Fungi are eukaryotic microorganisms that show complex life cycles, including both anamorph and teleomorph stages. Beta-1,3-1,6-glucans (BGs) are major cell wall components in fungi. BGs are also found in a soluble form and are secreted by fungal cells. Studies of fungal BGs extensively expanded from 1960 to 1990 due to their applications in cancer immunotherapy. However, progress in this field slowed down due to the low efficacy of such therapies. In the early 21st century, the discovery of C-type lectin receptors significantly enhanced the molecular understanding of innate immunity. Moreover, pathogen-associated molecular patterns (PAMPs) and pattern recognition receptors (PRRs) were also discovered. Soon, dectin-1 was identified as the PRR of BGs, whereas BGs were established as PAMPs. Then, studies on fungal BGs focused on their participation in the development of deep-seated mycoses and on their role as a source of functional foods. Fungal BGs may have numerous and complex linkages, making it difficult to systematize them even at the primary structure level. Moreover, elucidating the structure of BGs is largely hindered by the multiplicity of genes involved in cell wall biosynthesis, including those for BGs, and by fungal diversity. The present review mainly focused on the characteristics of fungal BGs from the viewpoint of structure and immunological activities.

Structural characterization and immunomodulatory mechanisms of two novel glucans from Morchella importuna fruiting bodies.

Two novel glucans named MIPB50-W and MIPB50-S-1 were obtained from edible Morchella importuna with molecular weights (Mw) of 939.2 kDa and 444.5 kDa, respectively. MIPB50-W has a backbone of α-(1 → 4)-d-glucan, which was substituted at O-6 position by α-d-Glcp-(1→. Moreover, MIPB50-S-1 has a backbone of α-(1 → 4)-d-glucan, which was substituted at O-6 position by α-d-Glcp-(1 → 6)-α-d-Glcp-(1→. This is the first report about glucan found in Morchella mushrooms. Furthermore, MIPB50-W and MIPB50-S-1 strengthened the phagocytosis function and the promoted secretion of interleukins (IL)-6/tumor necrosis factor-alpha (TNF-α) and nitric oxide (NO), which induced the activation of Toll-like receptor 2 (TLR2), TLR4 as well as mitogen activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) pathways. Interestingly, MIPB50-S-1 performed the better immunomodulatory activity than that of MIPB50-W in almost all tests. Therefore, MIPB50-W and MIPB50-S-1 are potential immune-enhancing components of functional foods.

Effect of Supplementing Seaweed Extracts to Pigs until d35 Post-Weaning on Performance and Aspects of Intestinal Health.

The objective of this study was to examine the effects of feeding laminarin (LAM) and fucoidan (FUC) enriched seaweed extracts up to d35 post-weaning on measures of animal performance, intestinal microbial and transcriptome profiles. 75 pigs were assigned to one of three groups: (1) basal diet; (2) basal diet + 250 ppm fucoidan; (3) basal diet + 300 ppm laminarin with 7 replicates per treatment group. Measures of performance were collected weekly and animals sacrificed on d35 post-weaning for the sampling of gastrointestinal tissue and digesta. Animal performance was similar between the basal group and the groups supplemented with FUC and LAM (P > 0.05). Pigs fed the basal diet had higher alpha diversity compared to both the LAM and FUC supplemented pigs (P < 0.05). Supplementation with LAM and FUC increased the production of butyric acid compared to basal fed pigs (P < 0.05). At genus level pigs fed the LAM supplemented diet had the greatest abundance of Faecalbacterium, Roseburia and the lowest Campylobacter of the three experimental treatments (P< 0.05). While neither extract had beneficial effects on animal performance, LAM supplementation had a positive influence on intestinal health through alterations in the gastrointestinal microbiome and increased butyrate production.

Purification and characterization of a novel mixed-linkage α,ß-d-glucan from Arca subcrenata and its immunoregulatory activity.

Arca subcrenata Lischke is a seafood with high nutritional value. In this study, we purified and characterized a novel water-soluble polysaccharide (ASPG-2) from Arca subcrenata with significant immunoregulatory effects and no apparent cell toxicity. ASPG-2 is a class of mixed-linkage α,ß-d-glucan backbones with α-linked side chains with a molecular weight of 4.39 × 105 Da. Its structure was characterized as a repeating unit consisting of (1 → 3)-ß-d-Glcp, (1 → 4)-α-d-Glcp, (1 → 4,6)-α-d-Glcp and (1 → 6)-α-d-Glcp. Using mouse RAW264.7 macrophages, we demonstrated that ASPG-2 exerted marked immunoregulatory effects by promoting the secretion of NO and increasing the phagocytosis of RAW264.7 cells in vitro. Moreover, flow cytometry analysis of the expression of the cell surface molecule CD86 revealed that ASPG-2 could polarize RAW264.7 cells into the M1 type. The immunomodulatory mechanism of ASPG-2 in macrophages was associated with the activation of the TLR4-MAPK/Akt-NF-κB signalling pathways. These results indicated that ASPG-2 might be researched and developed as a potential immunomodulatory agent or health product from marine organisms.

Structural characterization and hepatoprotective activity of a galactoglucan from Poria cocos.

To find the polysaccharide with hepatoprotective activity from Poria cocos and clarify its structure, a galactoglucan (PCP-1C) with a molecular weight of 17 kDa was purified from the Poria cocos sclerotium by column chromatography and activity evaluation in the present work. It was composed of galactose, glucose, mannose, and fucose in a molar percentage of 43.5: 24.4: 17.4: 14.6. Structural characterization showed that PCP-1C has a backbone consisted of 1,6-α-D-Galp, which branches composed of 1,3-ß-D-Glcp, 1,4-ß-D-Glcp, 1,6-ß-D-Glcp, T-ß-D-Glcp, T-α-D-Manp, T-α-L-Fucp and 1,3-α-L-Fucp. In vivo experiments found that PCP-1C can apparently improve the damage of liver tissue in CCl4-treated mice and relieve oxidative stress and inflammation. PCP-1C also reduced the expression of CAR and CYP2E1 in the liver. These findings indicated strong hepatoprotective effect of PCP-1C, which was attributed to the reduction of CCl4 metabolism via inhibiting the CAR/CYP2E1 signal pathway.

Effect of Polysaccharide Conformation on Ultrafiltration Separation Performance.

The manifold array of saccharide linkages leads to a great variety of polysaccharide architectures, comprising three conformations in aqueous solution: compact sphere, random coil, and rigid rod. This conformational variation limits the suitability of the commonly applied molecular weight cut-off (MWCO) as selection criteria for polysaccharide ultrafiltration membranes, as it is based on globular marker proteins with narrow Mw and hydrodynamic volume relation. Here we show the effect of conformation on ultrafiltration performance using randomly coiled pullulan and rigid rod-like scleroglucan as model polysaccharides for membrane rejection and molecular weight distribution. Ultrafiltration with a 10 kDa polyethersulfone membrane yielded significant different recoveries for pullulan and scleroglucan showing 1% and 71%, respectively. We found deviations greater than 77-fold between nominal MWCO and apparent Mw of pullulan and scleroglucan, while recovering over 90% polysaccharide with unchanged Mw. We anticipate our work as starting point towards an optimized membrane selection for polysaccharide applications.

Serology anno 2021-fungal infections: from invasive to chronic.

BACKGROUND: Diagnosing invasive or chronic fungal infections is a challenge, particularly in the immunocompromised host. Microscopy and culture remain the reference standard, but are insensitive. The use of non-culture-based techniques is recommended in conjunction with conventional methods to improve the diagnostic yield. OBJECTIVES: The aim was to provide an updated 2021 inventory of fungal antigen and serology tests for diagnosing invasive and chronic fungal infections, the key focus was set on Aspergillus, Candida and Cryptococcus species. SOURCES: Pubmed search for publications with the key words fungal antigen tests, laboratory-based diagnosis of invasive pulmonary aspergillosis, chronic pulmonary aspergillosis, invasive candidiasis, invasive fungal infections and cryptococcal infections published from 2017 to 2020. CONTENT: Antigen assays such as the galactomannan (GM) and ß-d-glucan detection systems are frequently used, but these tests vary in sensitivity and specificity, depending on the patient population involved, specimens inspected, cut-offs defined, test strategy applied and inclusion or exclusion of possible fungal case definitions. Multiple different detection systems are available, with recently introduced new point-of-care tests such as the lateral flow device and the lateral flow assay. Despite a wide heterogeneity in populations evaluated, studies indicate a better diagnostic performance of bronchoalveolar lavage GM in comparison with serum GM, and a suboptimal specificity of GM bronchoalveolar lavages (cut-off ≥1) and serum ß-d-glucan in non-neutropenic individuals. Point-of-care cryptococcal antigen tests show excellent performance. IMPLICATIONS: There are fungal antigen detection tests available with excellent to reasonable clinical performance to diagnose invasive fungal infections. Only a few assays are useful to monitor therapeutic response. There are multiple marketed IgG antibody tests to detect Aspergillus fumigatus antibodies, the titres vary widely and the performance differs significantly. In general, diagnostic tests are vulnerable to being affected by the host, the microbe and laboratory setting.

Biological Activity of High-Purity ß-1,3-1,6-Glucan Derived from the Black Yeast Aureobasidium pullulans: A Literature Review.

The black yeast Aureobasidium pullulans produces abundant soluble ß-1,3-1,6-glucan-a functional food ingredient with known health benefits. For use as a food material, soluble ß-1,3-1,6-glucan is produced via fermentation using sucrose as the carbon source. Various functionalities of ß-1,3-1,6-glucan have been reported, including its immunomodulatory effect, particularly in the intestine. It also exhibits antitumor and antimetastatic effects, alleviates influenza and food allergies, and relieves stress. Moreover, it reduces the risk of lifestyle-related diseases by protecting the intestinal mucosa, reducing fat, lowering postprandial blood glucose, promoting bone health, and healing gastric ulcers. Furthermore, it induces heat shock protein 70. Clinical studies have reported the antiallergic and triglyceride-reducing effects of ß-1,3-1,6-glucan, which are indicators of improvement in lifestyle-related diseases. The primary and higher-order structures of ß-1,3-1,6-glucan have been elucidated. Specifically, it comprises a single highly-branched glucose residue with the ß-1,6 bond (70% or more) on a backbone of glucose with 1,3-ß bonds. ß-Glucan shows a triple helical structure, and studies on its use as a drug delivery system have been actively conducted. ß-Glucan in combination with anti-inflammatory substances or fullerenes can be used to target macrophages. Based on its health functionality, ß-1,3-1,6-glucan is an interesting material as both food and medicine.

Structure of a laminarin-type ß-(1→3)-glucan from brown algae Sargassum henslowianum and its potential on regulating gut microbiota.

A homogeneous polysaccharide named SHNP with apparent molecular weight of 8.4 kDa was purified from brown algae Sargassum henslowianum using ethanol precipitation, ion-exchange chromatography, and gel-filtration column chromatography. Structural analyses reveal that SHNP is completely composed of glucose, and its backbone consists of ß-D-(1→3)-Glcp with side chains comprising t-ß-D-Glcp attached at the O-6 position. Thus, SHNP is a laminarin-type polysaccharide. In vitro fermentation test results showed that SHNP was digested by gut microbiota; the pH value in the fecal culture of SHNP was significantly decreased; and total short-chain fatty acids, acetic, propionic and n-butyric acids were significantly increased. Furthermore, SHNP regulated the intestinal microbiota composition by stimulating the growth of species belonging to Enterobacteriaceae while depleting Haemophilus parainfluenzae and Gemmiger formicilis. Taken together, these results indicate that SHNP has the potential for regulating gut microbiota, but its specific role in the regulation requires to be further investigated.

The antitumor role of a newly discovered α-d-glucan from Holotrichia diomphalia Bates as a selective blocker of aldolase A.

Aldolase A (ALDOA) facilitated aerobic glycolysis in cancer cells is a potential target in the treatment of hepatocellular carcinoma (HCC). However, only few effective inhibitors of ALDOA have been reported until now. In this research, we found a polysaccharide called HDPS-4II from Holotrichia diomphalia Bates, which can specifically bind to ALDOA with a dissociation constant of 2.86 µM. HDPS-4II with a molecular weight of 19 kDa was a linear triple-helix glucan composed of ɑ-d-1,4-Glcp and ɑ-d-1,6-Glcp in a ratio of 1.0:10.0. HDPS-4II significantly inhibited aldolase enzyme activity, glycolysis, and further inhibited the expression of phosphorylated AMPKα in HCC cells. Through analyzing ALDOA-overexpressing and -knockdown cells, it was confirmed that ALDOA mediated the viability and glycolysis inhibition of HDPS-4II. Moreover, HDPS-4II administration markedly inhibited tumor growth in mice xenografted with HCCs. These findings suggest that HDPS-4II, as an ALDOA antagonist, is a promising remedy in the treatment and prevention of HCC.

Synthesis of alternan-stabilized zinc nanoparticles: morphological, thermal, antioxidant and antimicrobial characterization.

This study aimed to synthesize zinc nanoparticles with antimicrobial and antioxidant activities using alternan (ZnNPs-Alt) produced by Lactobacillus reuteri E81 as the stabilizing agent. For the characterization of the ZnNPs-Alt, UV-vis spectroscopy, SEM, TEM and EDX analysis, XRD, FTIR and DSC analysis were applied. The functional role of ZnNPs-Alt was tested by determination of their antioxidant activities by DPPH and CUPRAC methodologies and their antibacterial and antifungal activities. Results of this study demonstrated that alternan was utilized as a successful stabilizer to produce crystalline, thermally stabile ZnNPs-Alt with a particle size of ∼ 100 nm. Importantly, strong antioxidant and antimicrobial activities were observed for ZnNPs-Alt in a concentration dependent manner. These findings confirmed the role of alternan as a stabilizing agent for the production of ZnNPs-Alt with functional roles.