Formation and Physiochemical Properties of Silver Nanoparticles with Various Exopolysaccharides of a Medicinal Fungus in Aqueous Solution

Natural polysaccharides are the most widely used biopolymers for green synthesis of eco-friendly silver nanoparticles (AgNPs). In a previous study, a high molecular weight (MW) fraction of exopolysaccharides (EPS) produced by a medicinal fungus Cs-HK1 has been shown useful for green and facile synthesis of AgNPs in water. This study was to further evaluate the effects of molecular properties of EPS on the formation, stability and properties of AgNPs with different EPS fractions at various pH conditions. Three EPS fractions (P_0.5, P_2.0 and P_5.0: MW high to low and protein content low to high) were reacted with silver nitrate at various pH 3.0-8.0 in water. The most favorable pH range was 5.5-8.0 for the formation and stable dispersion of AgNPs. At a given pH, the maximum amount of AgNPs was produced with P_5.0, and the minimum with P_0.5. The shape, size and physiochemical properties of AgNPs were strongly affected by the molecular characteristics of EPS (MW and conformation). The results may be helpful for understanding the factors and mechanisms for formation of stable AgNPs with natural polysaccharides and the interactions between AgNPs and the polysaccharide hydrocolloids in water.

Structure Elucidation of a Polysaccharide from Umbilicaria esculenta and Its Immunostimulatory Activity

Umbilicaria esculenta has been used as a tonic food in China for several centuries owing to its pleasant flavor and health benefits. In this study, a water soluble polysaccharide, which we designated as UP2, with an average molecular weight of 3.33 × 105 Da, was isolated from U. esculenta cultivated in the Huangshan Mountain, by consecutive hot water extraction and anion-exchange chromatography. Gas chromatography analysis indicated that UP2 contained three kinds of monosaccharides, including mannose, glucose, and galactose at a molar ratio of 1.7:1.0:1.2. Linkage analysis of UP2 revealed the presence of (1 → 6)-linked glucosyl, (1 → 3,6)-linked glucosyl, t-linked galactosyl, (1 → 6)-linked galactosyl and (1 → 6)-linked mannosyl at a molar ratio of 0.7:4.6:4.1:2.2:9.1. Structural analysis determined that UP2 possessed a backbone consisting of (1 → 6)-linked β-D-glucopyranosyl and (1 → 6)-linked α-D-mannopyranosyl residues, which substituted at the O-3 position of (1 → 6)-linked β-D-glucopyranosyl residues by branches of (1 → 6)-linked α-D-galactopyranosyl and 1-linked β-D-galactopyranosyl residues. Immunostimulatory activity analysis showed that UP2 could stimulate the proliferation of RAW264.7 cells in a dose-dependent manner, and all the samples (20-500 μg/mL) were found to enhance nitric oxide production. The highest phagocytic activity of UP2 was observed at 200 μg/mL. Thus, UP2 may be a potential source of biological and pharmacological agents.

Improved antioxidant and anti-tyrosinase activity of polysaccharide from Sargassum fusiforme by degradation

An efficient method for the degradation of polysaccharides isolated from Sargassum fusiforme (PSF) was developed by using ascorbic acid in combination with H2O2. The degradation conditions were optimized using a Box-Behnken response surface design (BBRS). The optimum conditions were established as: concentration of ascorbic acid (VC) and H2O2 17.26mM, degradation temperature 51°C and degradation time 1.6h. The DPPH radical scavenging rate of the degraded polysaccharides from S. fusiforme (DPSF) obtained under the optimal conditions was determined to be 75.22±0.02%, which was well matched with the value (75.21%) predicted by the BBRS model. In vitro antioxidant activity of the polysaccharides was evaluated by determining their radical (hydroxyl radical, superoxide anion radical and DPPH radical) scavenging abilities, and ferric iron reducing power. The inhibitory activity on tyrosinase of DPSF was also evaluated. The results indicate that the degraded polysaccharide has superior antioxidant activity and anti-tyrosinase effect to those of the original polysaccharide.

Optimization of cellulase-assisted extraction process and antioxidant activities of polysaccharides from Tricholoma mongolicum Imai

BACKGROUND

Tricholoma mongolicum Imai is a well-known edible and medicinal mushroom which in recent years has attracted increasing attention because of its bioactivities. In this study, water-soluble polysaccharides were extracted from T. mongolicum Imai by cellulase-assisted extraction and their antioxidant activities were investigated.

RESULTS

In order to improve the yield of polysaccharides, four variables, cellulase amount (X1 ), pH (X2 ), temperature (X3 ) and extraction time (X4 ), were investigated with a Box-Behnken design. The optimal conditions were predicted to be cellulase amount of 20 g kg(-1) , pH of 4.0, temperature of 50 °C and extraction time of 127 min, with a predicted polysaccharide yield of 190.1 g kg(-1) . The actual yield of polysaccharides under these conditions was 189.6 g kg(-1) , which matched the predicted value well. The crude polysaccharides were purified to obtain four fractions, and characterization of each was carried out. In addition, antioxidant properties of four polysaccharides assessed by 1,1-diphenyl-2-picryldydrazyl (DPPH) and hydroxyl radical-scavenging assays indicated that polysaccharides from T. mongolicum Imai (TMIPs) possessed antioxidant activity in a dose-dependent manner.

CONCLUSION

TMIPs show moderate antioxidant activities in vitro. Therefore it is suggested that TMIPs are potential natural antioxidants for use in functional foods. © 2016 Society of Chemical Industry.

Synthesis of part structures of Cryptococcus neoformans serotype C capsular polysaccharide

Cryptococcus neoformans is a fungal pathogen that can cause life-threatening infections in immunocompromised patients. The development of a vaccine based on the capsular polysaccharide of C. neoformans is still an open challenge due to the heterogeneity of the capsular polysaccharide and the difficulty of identifying protective epitopes. Therefore, construction of structurally defined part structures of the C. neoformans GXM capsule is in great demand. Herein is presented the synthesis of a 3-O-naphthalenylmethyl protected trisaccharide thioglycoside building block which is present in C. neoformans serotype C polysaccharide. Its property as a donor in a glycosylation reaction with a model acceptor has been evaluated together with its behaviour as an acceptor following removal of the temporary protecting group. The heavily branched hexasaccharide was obtained in good yields and excellent α-selectivity. The frame shifted octasaccharide structural triad motif for serotype C was also prepared following the same building block strategy. For the first time this structural motif, which is the most substituted amongst the four C. neoformans serotypes, was prepared. Three synthesized C. neoformans serotype C fragments of varying size, from penta-up to octasaccharide, were deprotected and will be included in unique glycoarrays to further investigate the possibility to develop a synthetic vaccine against this pathogen.

Characteristics and Antitumor Activity of Morchella esculenta Polysaccharide Extracted by Pulsed Electric Field

Polysaccharides from Morchella esculenta have been proven to be functional and helpful for humans. The purpose of this study was to investigate the chemical structure and anti-proliferating and antitumor activities of a Morchella esculenta polysaccharide (MEP) extracted by pulsed electric field (PEF) in submerged fermentation. The endo-polysaccharide was separated and purified by column chromatography and Gel permeation chromatography, and analyzed by gas chromatography. The MEP with an average molecular weight of 81,835 Da consisted of xylose, glucose, mannose, rhamnose and galactose at the ratio of 5.4:5.0:6.5:7.8:72.3. Structure of MEP was further analyzed by Fourier-transform infrared spectroscopy and ¹H and ¹³C liquid-state nuclear magnetic resonance spectroscopy. Apoptosis tests proved that MEP could inhibit the proliferation and growth of human colon cancer HT-29 cells in a time- and dose-dependent manner within 48 h. This study provides more information on chemical structure of anti-proliferating polysaccharides isolated from Morchella esculenta.

Effect of exopolysaccharide from Ganoderma applanatum on the electrical properties of mouse fibroblast cells line L929 culture using an electric cell-substrate impedance sensing (ECIS) - Preliminary study

IIntroduction and objective. In recent years there has been intensified research on medicinal preparations of fungal origin. Some fungal polysaccharides may directly affect the inhibition of cancer cells proliferation which, stopping the cell cycle, leads to apoptosis. One of these substances (component of extract of Ganoderma spp) is extensively tested for its anti-cancer properties on the tumor cell lines. Electric cell-substrate impedance sensing (ECIS) is an in vitro impedance measuring system using alternating current (AC) to determinate the behaviour of the cells in physiological conditions.

OBJECTIVE

The aim of the study was to examine the electric properties (resistance, capacitance and impedance) of mouse fibroblasts cell line L929 after treatment by different concentration of crude exopolysaccharides from Ganoderma applanatum (GpEPS) in real time by ECIS technique.

MATERIALS AND METHODS

For the study, the L929 cell line culture was treated by different concentrations of GpEPS: C1=228.5 µg/mL; C2=22.85 µg/mL; C3=2.285 µg/mL; C4=0.2285 µg/mL; and C5=0.02285 µg/mL. Default optimal frequencies were used: Resistance (R) 4000Hz, Impedance (Z) 16000Hz, Capacitance (C) 64000Hz.

RESULTS

The study demonstrated that GpEPS had no significant effect on the resistance, capacitance and impedance cells cultures, which implies that there is no significant effect on the physiological processes of L929 fibroblasts. This indicates the possibility of using GpEPS preparation in anti-cancer therapy.

CONCLUSIONS

In the future, following further studies (comprising in preventive and therapeutic actions), GpEPS can be safely used in anti-cancer therapy which does not cause side-effects or damage to healthy cells.

Purification, Chemical Characterization, and Bioactivity of an Extracellular Polysaccharide Produced by the Marine Sponge Endogenous Fungus Alternaria sp. SP-32

Marine sponges are ancient and simple multicellular filter-feeding invertebrates attached to solid substrates in benthic habitats and host a variety of fungi both inside and on their surface because of its unique ingestion and digest system. Investigation on marine sponge-associated fungi mainly focused on the small molecular metabolites, yet little attention had been paid to the extracellular polysaccharides. In this study, a homogeneous extracellular polysaccharide AS2-1 was obtained from the fermented broth of the marine sponge endogenous fungus Alternaria sp. SP-32 using ethanol precipitation, anion-exchange, and size-exclusion chromatography. Results of chemical and spectroscopic analyses showed that AS2-1 was composed of mannose, glucose, and galactose with a molar ratio of 1.00:0.67:0.35, and its molecular weight was 27.4 kDa. AS2-1 consists of a mannan core and a galactoglucan chain. The mannan core is composed of (1→6)-α-Manp substituted at C-2 by (1→2)-α-Manp with different degrees of polymerization. The galactoglucan chain consists of (1→6)-α-Glcp residues with (1→6)-β-Galf residues attached to the last glucopyranose residue at C-6. (1→6)-β-Galf residues have additional branches at C-2 consisting of disaccharide units of (1→2)-β-Galf and (1→2)-α-Glcp residues. The glucopyranose residue of the galactoglucan chain is linked to the mannan core. AS2-1 possessed a high antioxidant activity as evaluated by scavenging of 1,1-diphenyl-2-picrylhydrazyl and hydroxyl radicals in vitro. AS2-1 was also evaluated for cytotoxic activity on Hela, HL-60, and K562 cell lines by the MTT and SRB methods. The investigation demonstrated that AS2-1 was a novel extracellular polysaccharide with different characterization from extracellular polysaccharides produced by other marine microorganisms.

Antitumor and Antioxidant Properties of Water-Soluble Polysaccharides from Submerged Mycelium of Flammulina velutipes

The aim of the study was to evaluate antitumor and antioxidant properties of water-soluble polysaccharides from submerged myceliumn of Flammulina velutipes grown under optimized conditions. The optimization of the nutrient medium composition allowed to increase the biomass yield by more than 2 times (up to 35 g/l) and to reduce the time of the cultivation process. The submerged mycelium of F.velutipes strain Fv-1 contained 14.8% of a water-soluble polysaccharides, 31.6% of proteins, 2.5% of total lipids, vitamins B (B1, B5, B6). The polysaccharides contained glucose, galactose, fucose, mannose, xylose, rhamnose. The proteins contained all the essential amino acids except for tryptophan. Dry powder of the submerged mycelium, water extract of the mycelium and total fraction of the water-soluble polysaccharides demonstrated the antitumor activity against murine lymphocytic leukemia P 388 in vivo. The antitumor activity of the substances was mainly due to the polysaccharides, since their purification increased the tumor growth inhibition. The maximum tumor growth inhibition by the water-soluble polysaccharides amounted to 94%. The total fraction of the water-soluble polysaccharides from F.velutipes strain Fv-1 demonstrated antioxidant activity. The antioxidant capacity (AOC) of the water-soluble fraction from F.velutipes was higher than that of the water-soluble polysaccharides from the sub- merged mycelium of Grifolafrondosa, but inferior to the AOC of the water-soluble polysaccharides from the submerged mycelium of Ganoderma luciduma.

[ON DEVELOPMENT OF TOOLS OF IMMUNE DIAGNOSTIC OF INFECTIOUS DISEASES: PROBLEMS OF DIAGNOSTIC IN VIVO AND IN VITRO]

The article considers a number of problematic issues concerning development of effective means of immune diagnostic of infectious diseases of bacterial and mycotic etiology related to approaches of choosing appropriate diagnostic targets.

Extracellular polysaccharides from Ascomycota and Basidiomycota: production conditions, biochemical characteristics, and biological properties

Fungal polysaccharides (PSs) are the subject of research in many fields of science and industry. Many properties of PSs have already been confirmed and the list of postulated functions continues to grow. Fungal PSs are classified into different groups according to systematic affinity, structure (linear and branched), sugar composition (homo- and heteropolysaccharides), type of bonds between the monomers (β-(1 → 3), β-(1 → 6), and α-(1 → 3)) and their location in the cell (cell wall PSs, exoPSs, and endoPSs). Exopolysaccharides (EPSs) are most frequently studied fungal PSs but their definition, classification, and origin are still not clear and should be explained. Ascomycota and Basidiomycota fungi producing EPS have different ecological positions (saprotrophic and endophytic, pathogenic or symbiotic-mycorrhizae fungi); therefore, EPSs play different biological functions, for example in the protection against environmental stress factors and in interactions with other organisms. EPSs obtained from Ascomycota and Basidiomycota fungal cultures are known for their antioxidant, immunostimulating, antitumor, and antimicrobial properties. The major objective of the presented review article was to provide a detailed description of the state-of-the-art knowledge of the effectiveness of EPS production by filamentous and yeast Ascomycota and Basidiomycota fungi and techniques of derivation of EPSs, their biochemical characteristics, and biological properties allowing comprehensive analysis as well as indication of similarities and differences between these fungal groups. Understanding the role of EPSs in a variety of processes and their application in food or pharmaceutical industries requires improvement of the techniques of their derivation, purification, and characterization. The detailed analyses of data concerning the derivation and application of Ascomycota and Basidiomycota EPSs can facilitate development and trace the direction of application of these EPSs in different branches of industry, agriculture, and medicine.

Antioxidant and anti-ageing activities of mycelia zinc polysaccharide from Pholiota nameko SW-03

BACKGROUND

Edible fungi polysaccharides usually exhibit antioxidant activity, and zinc has been shown to have antioxidant properties. In the present work, Pholiota nameko SW-03 was used as a vector of zinc biotransformation in order to obtain mycelia zinc polysaccharide (MZPS), and the structural characterization and anti-ageing activity of MZPS were investigated.

RESULTS

Pholiota nameko SW-03 could accumulate zinc in the form of zinc-enriched polysaccharide, and the zinc content in MZPS was 16.39 ± 0.72 mg g(-1) . Three fractions (MZPS-1, MZPS-2 and MZPS-3) were successfully isolated. The main fraction (MZPS-2) with the highest antioxidant activity in vitro was composed of glucose, mannose, glucuronic acid, galactose, galacturonic acid and arabinose in a molar ratio of 172.59:5.29:4.61:4.20:1.01:1.00, with a weight-average molecular weight of 13.63 kDa. The anti-ageing capability was measured in d-galactose-induced ageing mice, and the results showed that MZPS could improve antioxidant status (superoxide dismutase, total antioxidant capability, malondialdehyde and lipid peroxide), indicating that MZPS had strong anti-ageing capability in vivo.

CONCLUSION

This study suggested that organification of zinc through edible fungi liquid fermentation provided a novel method to produce MZPS, which might be used as a natural antioxidant to slow the progression of ageing.

Structural characterization and antioxidant activity of a novel heteropolysaccharide from the submerged fermentation mycelia of Ganoderma capense

A novel heteropolysaccharide (GCPB-2) with a molecular mass of 1.03×10(5)Da was isolated from the submerged fermentation culturing mycelia powder of Lingzhi, Ganoderma capense, by DEAE-52 cellulose, DEAE Sepharose CL-6B, and Sephadex G-75 column chromatography. Its chemical structure was characterized for the first time. The antioxidant activity was evaluated by two antioxidant assay methods. The result of this study introduced G. capense as a possible valuable source that helped to exhibit some antioxidant properties. The homogeneous polysaccharide was composed of xylose and arabinose in the molar ratio of 1:1, and showed a specific optical rotation of [α]D(25)=+161° (c 1.0, H2O). Monosaccharide analysis, partial acid hydrolysis, periodic acid oxidation, methylation analysis, gas chromatography-mass spectrometry (GC-MS), Fourier transform-infrared spectroscopy (FT-IR), and nuclear magnetic resonance (NMR) spectroscopy ((1)H, (13)C, HMQC and HMBC) were conducted to elucidate its structure. The backbone of GCPB-2 was composed of (1 → 4)-linked-β-D-xylopyranose residues which branched at O-3. The two branches consisted of (1 → 3)-linked-β-L-arabinopyranose terminated with β-D-xylopyranose residues, and (1 → 4)-linked-β-L-arabinopyranose terminated with β-D-arabinopyranose residues. In the in vitro antioxidant assay, GCPB-2 was found to possess 1-diphenyl-2-picryl-hydrazyl (DPPH) radical-scavenging activity with an EC50 value of 0.379 μM. The findings of this study indicated that GCPB-2 possesses the hydroxyl radical-scavenging activity, which provided an experimental evidence to support the G. capense as functional foods in some Asian countries. To understand better the bioactivity of GCPB-2, the antioxidant activity should be further investigated to find out its mechanism in future work.

A Multifaceted Study of Scedosporium boydii Cell Wall Changes during Germination and Identification of GPI-Anchored Proteins

Scedosporium boydii is a pathogenic filamentous fungus that causes a wide range of human infections, notably respiratory infections in patients with cystic fibrosis. The development of new therapeutic strategies targeting S. boydii necessitates a better understanding of the physiology of this fungus and the identification of new molecular targets. In this work, we studied the conidium-to-germ tube transition using a variety of techniques including scanning and transmission electron microscopy, atomic force microscopy, two-phase partitioning, microelectrophoresis and cationized ferritin labeling, chemical force spectroscopy, lectin labeling, and nanoLC-MS/MS for cell wall GPI-anchored protein analysis. We demonstrated that the cell wall undergoes structural changes with germination accompanied with a lower hydrophobicity, electrostatic charge and binding capacity to cationized ferritin. Changes during germination also included a higher accessibility of some cell wall polysaccharides to lectins and less CH₃/CH₃ interactions (hydrophobic adhesion forces mainly due to glycoproteins). We also extracted and identified 20 GPI-anchored proteins from the cell wall of S. boydii, among which one was detected only in the conidial wall extract and 12 only in the mycelial wall extract. The identified sequences belonged to protein families involved in virulence in other fungi like Gelp/Gasp, Crhp, Bglp/Bgtp families and a superoxide dismutase. These results highlighted the cell wall remodeling during germination in S. boydii with the identification of a substantial number of cell wall GPI-anchored conidial or hyphal specific proteins, which provides a basis to investigate the role of these molecules in the host-pathogen interaction and fungal virulence.

Relationship of chemical composition and cytotoxicity of water-soluble polysaccharides from Lentinus edodes fruiting bodies

Six water-soluble polysaccharides (S-WPLE-I-a, S-WPLE-I-b, S-WPLE-II-a, S-WPLE-II-b, S-WPLE-III-a and S-WPLE-III-b) were obtained from Lentinus edodes and purified by gel-permeation chromatography (GPC). The fractions were analyzed for monosaccharide composition, molecular weight, and then tested for cytotoxicity activity. The results from high performance liquid chromatography (HPLC) revealed that the water-soluble fractions were heteroglucan containing mainly glucose (Glc), galactose (Gal) and mannose (Man) at various ratios. All the polysaccharide fractions exhibited antitumor activities against Sarcoma 180 (S-180) solid tumor cells and human colorectal cancer cell lines (HT-29 and HCT-116) in vitro at the dose of 5mg/ml. The antitumor activities of the polysaccharides were related to their monosaccharide content and molecular weight. The effects of Gal, Man and bound protein on the improvement of antitumor activities of polysaccharides might not be negligible. The results also revealed that there was selectively higher antitumor activity of the polysaccharides against suspended cells (S-180) than adherent ones (HT-29 and HCT-116).

Structural characterization and biological activities of a novel polysaccharide from cultured Cordyceps militaris and its sulfated derivative

A novel polysaccharide (CMPA90-1; compound 1) was isolated from the cultured fruiting bodies of Cordyceps militaris. The chemical structure of compound 1 was elucidated by acid hydrolysis, periodate oxidation, Smith degradation, and methylation analysis, along with Fourier transform infrared spectroscopy, high-performance anion-exchange chromatography coupled with pulsed amperometric detection, gas chromatography-mass spectrometry, and one-dimensional [(1)H and (13)C nuclear magnetic resonance (NMR)] and two-dimensional NMR (heteronuclear single-quantum coherence and heteronuclear multiple-bond correlation). Sulfation of compound 1 by the chlorosulfonic acid-pyridine (CSA-Pyr) method led to synthesis of its sulfated analogue (CMPA90-M1; compound 2). The ultrastructures of both compounds 1 and 2 were further characterized by scanning electron microscopy and atomic force microscopy. The results of antioxidant assays showed that compounds 1 and 2 exhibited free-radical-scavenging effects, ferrous-ion-chelating ability, and reducing power. Also, in the cytotoxicity assay, compounds 1 and 2 showed inhibitory activity against A549 cells, with IC50 values of 39.08 and 17.33 μg/mL, respectively.

A novel biosurfactant produced by Aureobasidium pullulans L3-GPY from a tiger lily wild flower, Lilium lancifolium Thunb

Yeast biosurfactants are important biotechnological products in the food industry, and they have medical and cosmeceutical applications owing to their specific modes of action, low toxicity, and applicability. Thus, we have isolated and examined biosurfactant-producing yeast for various industrial and medical applications. A rapid and simple method was developed to screen biosurfactant-producing yeasts for high production of eco-friendly biosurfactants. Using this method, several potential niches of biosurfactant-producing yeasts, such as wild flowers, were investigated. We successfully selected a yeast strain, L3-GPY, with potent surfactant activity from a tiger lily, Lilium lancifolium Thunb. Here, we report the first identification of strain L3-GPY as the black yeast Aureobasidium pullulans. In addition, we isolated a new low-surface-tension chemical, designated glycerol-liamocin, from the culture supernatant of strain L3-GPY through consecutive chromatography steps, involving an ODS column, solvent partition, silica gel, Sephadex LH-20, and an ODS Sep-Pak cartridge column. The chemical structure of glycerol-liamocin, determined by mass spectrometry and nuclear magnetic resonance spectroscopy, indicates that it is a novel compound with the molecular formula C33H62O12. Furthermore, glycerol-liamocin exhibited potent biosurfactant activity (31 mN/m). These results suggest that glycerol-liamocin is a potential novel biosurfactantfor use in various industrial applications.

Drying enhances immunoactivity of spent brewer's yeast cell wall β-D-glucans

Due to immunological activity, microbial cell wall polysaccharides are defined as 'biological response modifiers' (BRM). Cell walls of spent brewer's yeast also have some BRM activity. However, up to date there is no consensus on the use of spent brewer's yeast D-glucan as specific BRM in humans or animals. The aim of this paper is to demonstrate the potential of spent brewer's yeast β-D-glucans as BRM, and drying as an efficient pretreatment to increase β-D-glucan's immunogenic activity. Our results revealed that drying does not change spent brewer's yeast biomass carbohydrate content as well as the chemical structure of purified β-D-glucan. However, drying increased purified β-D-glucan TNF-α induction activity in the murine macrophage model. We presume drying pretreatment enhances purity of extracted β-D-glucan. This is corroborated with FT-IR analyses of the β-D-glucan spectra. Based on our results, we suggest that dry spent brewer's yeast biomass can be used as a cheap source for high-quality β-D-glucan extraction. Drying in combination with carboxylmethylation (CM), endows spent brewer's yeast β-D-glucan with the immunoactivity similar or exceeding that of a well-characterized fungal BRM pleuran.

Preparation and characterization of a novel extracellular polysaccharide with antioxidant activity, from the mangrove-associated fungus Fusarium oxysporum

Marine fungi are recognized as an abundant source of extracellular polysaccharides with novel structures. Mangrove fungi constitute the second largest ecological group of the marine fungi, and many of them are new or inadequately described species and may produce extracellular polysaccharides with novel functions and structures that could be explored as a source of useful polymers. The mangrove-associated fungus Fusarium oxysporum produces an extracellular polysaccharide, Fw-1, when grown in potato dextrose-agar medium. The homogeneous Fw-1 was isolated from the fermented broth by a combination of ethanol precipitation, ion-exchange, and gel filtration chromatography. Chemical and spectroscopic analyses, including one- and two-dimensional nuclear magnetic resonance spectroscopies showed that Fw-1 consisted of galactose, glucose, and mannose in a molar ratio of 1.33:1.33:1.00, and its molecular weight was about 61.2 kDa. The structure of Fw-1 contains a backbone of (1 → 6)-linked β-D-galactofuranose residues with multiple side chains. The branches consist of terminal α-D-glucopyranose residues, or short chains containing (1 → 2)-linked α-D-glucopyranose, (1 → 2)-linked β-D-mannopyranose, and terminal β-D-mannopyranose residues. The side chains are connected to C-2 of galactofuranose residues of backbone. The antioxidant activity of Fw-1 was evaluated with the scavenging abilities on hydroxyl, superoxide, and 1,1-diphenyl-2-picrylhydrazyl radicals in vitro, and the results indicated that Fw-1 possessed good antioxidant activity, especially the scavenging ability on hydroxyl radicals. The investigation demonstrated that Fw-1 is a novel galactofuranose-containing polysaccharide with different structural characteristics from extracellular polysaccharides from other marine microorganisms and could be a potential source of antioxidant.

The adjuvant effects of high-molecule-weight polysaccharides purified from Antrodia cinnamomea on dendritic cell function and DNA vaccines

The biological activity of the edible basidiomycete Antrodia cinnamomea (AC) has been studied extensively. Many effects, such as anti-cancer, anti-inflammatory, and antioxidant activities, have been reported from either crude extracts or compounds isolated from AC. However, research addressing the function of AC in enhancing immunity is rare. The aim of the present study is to investigate the active components and the mechanism involved in the immunostimulatory effect of AC. We found that polysaccharides (PS) in the water extract of AC played a major role in dendritic cell (DC) activation, which is a critical leukocyte in initiating immune responses. We further size purified and identified that the high-molecular weight PS fraction (greater than 100 kDa) exhibited the activating effect. The AC high-molecular weight PSs (AC hmwPSs) promoted pro-inflammatory cytokine production by DCs and the maturation of DCs. In addition, DC-induced antigen-specific T cell activation and Th1 differentiation were increased by AC hmwPSs. In studying the molecular mechanism, we confirmed the activation of the MAPK and NF-κB pathways in DCs after AC hmwPSs treatment. Furthermore, we demonstrated that TLR2 and TLR4 are required for the stimulatory activity of AC hmwPSs on DCs. In a mouse tumor model, we demonstrated that AC hmwPSs enhanced the anti-tumor efficacy of the HER-2/neu DNA vaccine by facilitating specific Th1 responses. Thus, we conclude that hmwPSs are the major components of AC that stimulate DCs via the TLR2/TLR4 and NF-κB/MAPK signaling pathways. The AC hmwPSs have potential to be applied as adjuvants.

Lentinula edodes-derived polysaccharide alters the spatial structure of gut microbiota in mice

Lentinula edodes-derived polysaccharides possess many therapeutic characteristics, including anti-tumor and immuno-modulation. The gut microbes play a critical role in modulation of immune function. However, the impact of Lentinula edodes-derived polysaccharides on the gut microbes have not yet been explored. In this study, high-throughput pyrosequencing technique was employed to investigate the effects of a new heteropolysaccharide L2 from Lentinula edodes on microbiota diversity and composition of small intestine, cecum, colon and distal end of colon (feces) in mice. The results demonstrated that along mouse intestine the microbiota exhibit distinctly different space distribution. L2 treatment reduced the diversity and evenness of gut microbiota along the intestine, especially in the cecum and colon. In the fecal microbial communities, the decrease of Bacteroidetes by significantly increasing Proteobacteria were observed, which were characterized by the increased Helicobacteraceae and reduced S24-7 at family level. Some OTUs, corresponding to Bacteroides acidifaciens, Alistipes and Helicobacter suncus, were found to be significantly increased in L2 treated-mice. In particular, 4 phyla Chloroflexi, Gemmatimonadetes, Nitrospirae and Planctomycetes are exclusively present in L2-treated mice. This is helpful for further demonstrating healthy action mechanism of Lentinula edodes-derived polysaccharide L2.

Evaluation of the efficiency of different disruption methods on yeast cell wall preparation for β-glucan isolation

Selected methods for yeast cell disruption were evaluated to establish their suitability for cell wall preparation in the process of β-glucan isolation. The effect of different disruption methods on contents of total saccharides, β-glucans and proteins in the produced cell walls preparations was analyzed. The degree of cell wall purification from intracellular components was established on the basis of the ratio of solubilised material. The investigated methods included: cell exposure to hot water (autoclaving), thermally-induced autolysis, homogenization in a bead mill, sonication and their combinations. Experimental systems were prepared in water (pH 5.0 and pH 7.0) and Tris-HCl buffer (pH 8.0). The Saccharomyces cerevisiae yeast cell wall preparations with the highest degree of cytosol component release and purification of β-glucans were produced by 30 min of cell homogenization with zirconium-glass beads (0.5 mm in diameter). This was confirmed by the highest ratio of solubilised material (approx. 64%–67%). The thus-produced preparations contained ca. 60% of total saccharides, 13%–14% of β(1,3)/(1,6)-glucans, and approx. 35% of crude proteins. Similar results were obtained after autolysis coupled with bead milling as well as with sonication, but the time required for these processes was more than 24 h. Homogenization in a bead mill could be valuable for general isolation procedures because allows one to eliminate the different autolytic activity of various yeast strains.

Fluconazole alters the polysaccharide capsule of Cryptococcus gattii and leads to distinct behaviors in murine Cryptococcosis

Cryptococcus gattii is an emergent human pathogen. Fluconazole is commonly used for treatment of cryptococcosis, but the emergence of less susceptible strains to this azole is a global problem and also the data regarding fluconazole-resistant cryptococcosis are scarce. We evaluate the influence of fluconazole on murine cryptococcosis and whether this azole alters the polysaccharide (PS) from cryptococcal cells. L27/01 strain of C. gattii was cultivated in high fluconazole concentrations and developed decreased drug susceptibility. This phenotype was named L27/01F, that was less virulent than L27/01 in mice. The physical, structural and electrophoretic properties of the PS capsule of L27/01F were altered by fluconazole. L27/01F presented lower antiphagocytic properties and reduced survival inside macrophages. The L27/01F did not affect the central nervous system, while the effect in brain caused by L27/01 strain began after only 12 hours. Mice infected with L27/01F presented lower production of the pro-inflammatory cytokines, with increased cellular recruitment in the lungs and severe pulmonary disease. The behavioral alterations were affected by L27/01, but no effects were detected after infection with L27/01F. Our results suggest that stress to fluconazole alters the capsule of C. gattii and influences the clinical manifestations of cryptococcosis.

Preparation, characterization and bioactivities of derivatives of an exopolysaccharide from Lachnum

An exopolysaccharide, obtained previously LEP-2b from Lachnum YM405, was phosphated and sulfated successfully. The derivatives named PLEP-2b and SLEP-2b, respectively, and their respective degree of substitution were 0.174 and 0.431. Phosphate groups -PO3H2 substituted at C-6 of 1,4-β-D-mannopyranose, C-5 of 2,6-β-d-1-OMe-mannofuranoside, C-3 of 1,6-β-D-galactopyranose, C-2 of 1-β-D-glucopyranose, and C-6 of 1,2-α-D-rhampyranose, while sulfate groups SO3H were mainly at C-6 of 1,4-β-D-Manp, C-6 of 1-β-D-Glcp and C-6 of 1,2-α-D-Rhap. Compared with LEP-2b, the scavenging effects of the derivatives, on hydroxyl radical and superoxide anion were significantly increased after the modifications, except for reducing power. Meanwhile, phosphorylated and sulfated modifications remarkably strengthened the inhibiting effect of LEP-2b on the proliferation of CT-26 murine colon carcinoma, Lewis lung carcinoma and human hepatocellular carcinoma HepG2 cells. The derivatives significantly enhanced the antioxidant and antitumor activities in vitro. Compared with sulfation, phosphorylation improved the inhibitory effect more contraposingly on some specific tumor cells.

Ex vivo and in vivo studies of CME-1, a novel polysaccharide purified from the mycelia of Cordyceps sinensis that inhibits human platelet activation by activating adenylate cyclase/cyclic AMP

INTRODUCTION

CME-1, a novel water-soluble polysaccharide, was purified from the mycelia of Cordyceps sinensis, and its chemical structure was characterized to contain mannose and galactose in a ratio of 4:6 (27.6 kDa). CME-1 was originally observed to exert a potent inhibitory effect on tumor migration and a cytoprotective effect against oxidative stress. Activation of platelets caused by arterial thrombosis is relevant to various cardiovascular diseases (CVDs). However, no data are available concerning the effects of CME-1 on platelet activation. Hence, the purpose of this study was to examine the ex vivo and in vivo antithrombotic effects of CME-1 and its possible mechanisms in platelet activation.

METHODS

The aggregometry, immunoblotting, flow cytometric analysis and platelet functional analysis were used in this study.

RESULTS

CME-1 (2.3-7.6 μM) exhibited highly potent activity in inhibiting human platelet aggregation when stimulated by collagen, thrombin, and arachidonic acid but not by U46619. CME-1 inhibited platelet activation accompanied by inhibiting Akt, mitogen-activated protein kinases (MAPKs), thromboxane B2 (TxB2) and hydroxyl radical (OH(●)) formation. However, CME-1 interrupted neither FITC-triflavin nor FITC-collagen binding to platelets. CME-1 markedly increased cyclic AMP levels, but not cyclic GMP levels, and stimulated vasodilator-stimulated phosphoprotein (VASP) phosphorylation. SQ22536, an inhibitor of adenylate cyclase, but not ODQ, an inhibitor of guanylate cyclase, obviously reversed the CME-1-mediated effects on platelet aggregation and vasodilator-stimulated phosphoprotein (VASP), Akt, p38 MAPK phosphorylation, and TxB2 formation. CME-1 substantially prolonged the closure time of whole blood and the occlusion time of platelet plug formation.

CONCLUSION

This study demonstrates for the first time that CME-1 exhibits highly potent antiplatelet activity that may initially activate adenylate cyclase/cyclic AMP and, subsequently, inhibit intracellular signals (such as Akt and MAPKs), ultimately inhibiting platelet activation. This novel role of CME-1 indicates that CME-1 exhibits high potential for application in treating and preventing CVDs.