Preparation of microparticulate beta-glucan from Saccharomyces cerevisiae for use in immune potentiation

How does a Saccharomyces cerevisiae extract influence the components of isolated rotavirus particles from stool samples collected in a clinical setting from children?

Human Rotavirus (HRV) is the causative pathogen of severe acute enteric infections that cause mortality among children worldwide. This study focuses on developing a new and effective treatment for rotavirus infection using an extract from Saccharomyces cerevisiae, aiming to make this treatment easily accessible to everyone. 15 antigens and 26 antibodies were detected in serum and stool using ELISA. The titers of HRVq1, HRVq2, HRVC1, and HRVC2 on Vero cells were determined to be 1.2x106, 3.0x106, 4.2x106, and 7.5x105 (Plaque forming unit, PFU/ml) four days after infection, respectively. The HRVq1 isolate induced cytopathic effects, i.e., forming multinucleated, rounded, enlarged, and expanding gigantic cells. RT-PCR identified this isolate, and the accession number 2691714 was assigned to GeneBank. The molecular docking analysis revealed that nonstructural proteins (NSPs) NSP1, NSP2, NSP3, NSP4, NSP5, and NSP6 exhibited significant binding with RNA. NSP2 demonstrated the highest binding affinity and the lowest binding energy (-8.9 kcal/mol). This affinity was maintained via hydrophobic interactions and hydrogen bonds spanning in length from 1.12 Å to 3.11 Å. The ADMET and bioactivity predictions indicated that the yeast extract possessed ideal solubility, was nontoxic, and did not cause cancer. The inhibitory constant values predicted for the S. cerevisiae extract in the presence of HRV vital proteins varied from 5.32 to 7.45 mM, indicating its potential as a viable drug candidate. Saccharomyces cerevisiae extract could be utilized as a dietary supplement to combat HRV as an alternative dietary supplement.

Obligatory role of microglia-mobilized hippocampal CREB-BDNF signaling in the prophylactic effect of β-glucan on chronic stress-induced depression-like behaviors in mice

Our previous studies have reported that pre-stimulation of microglia before stress stimulation is a possible strategy to prevent depression-like phenotypes; however, the molecular mechanisms underlying this effect are still unclear. Here, we used β-glucan, a polysaccharide from Saccharomyces cerevisiae with immunomodulatory activities that cannot elicit pro-inflammatory responses in microglia, to address this issue. Our results showed that a single injection of β-glucan one day before stress exposure dose-dependently prevented the depression-like behaviors triggered by chronic unpredictable stress (CUS), which peaked at 20 mg/kg and prevented the impairment of hippocampal brain-derived neurotrophic factor (BDNF) signaling, a pathological process critical for the progression of depression-like phenotypes. Inhibition of BDNF signaling by infusion of an anti-BDNF antibody into the hippocampus, knock-in of the mutant BDNF Val68Met allele, or blockade of the BDNF receptor in the hippocampus abolished the preventive effect of β-glucan on CUS-induced depression-like behaviors. Further analysis showed that cAMP-response element binding protein (CREB)-mediated increase of BDNF expression in the hippocampus was essential for the prevention of depression-like phenotypes by β-glucan. Pretreatment with minocycline or PLX3397 before β-glucan injection to suppress microglia abolished the preventive effect of β-glucan on impaired CREB-BDNF signaling in the hippocampus and depression-like behaviors in CUS mice. These results suggest that an increase in hippocampal BDNF following CREB activation triggered by β-glucan-induced microglia stimulation and subsequent TrkB signaling mediates the preventive effect of β-glucan on depression. β-Glucan may be a more suitable immunostimulant for the prevention of depression due to its inability to promote pro-inflammatory responses in microglia.

Beta glucan as an immune stimulant in tumor microenvironment - Insight into lessons and promises from past decade

Cancer is characterized by a perturbed immune landscape. Inside tumor microenvironment, immune system is reprogrammed to facilitate tumor growth and survival rather than eliminating it. This immune evasive mechanism needs to be reversed to normal for effective anticancer therapeutic strategy. Immunotherapy has emerged as a novel strategy for redeployment of immune cells against cancer. However, they suffer in their efficacy, response rate and side effects. This necessitated us to turn toward natural repertoires which can act as a substitute to conventional immunotherapeutics. Beta glucan, a polysaccharide derived from mushroom, serves the role of immunomodulator inside tumor microenvironment. It acts as pathogen associated molecular pattern and bind to various pattern recognition receptors expressed on surface of immune cells thereby facilitating their activation and crosstalk. This result in resurgence of suppressed immune surveillance in the tumor milieu. In this review, we highlight in brief the advances and limitation of cancer immunotherapy. Alongside, we have discussed the detailed mechanistic principle and recent advances underlying restoration of immune functionality by beta glucan.

β-Glucan attenuates cognitive impairment of APP/PS1 mice via regulating intestinal flora and its metabolites

BACKGROUND

The intestinal flora has been shown to be involved in the progression of Alzheimer's disease (AD) and can be improved by β-glucan, a polysaccharide derived from Saccharomyces cerevisiae, which affects cognitive function through the intestinal flora. However, it is not known if this effect of β-glucan is involved in AD.

METHOD

This study used behavioral testing to measure cognitive function. After that, high-throughput 16 S rRNA gene sequencing and GC-MS were used to analyze the intestinal microbiota and metabolite SCFAs of AD model mice, and further explore the relationship between intestinal flora and neuroinflammation. Finally, the expressions of inflammatory factors in the mouse brain were detected by Western blot and Elisa methods.

RESULTS

We found that appropriate supplementation of β-glucan during the progression of AD can improve cognitive impairment and reduce A β plaque deposition. In addition, supplementation of β-glucan can also promote changes in the composition of the intestinal flora, thereby changing the flora metabolites in the intestinal content and reduce the activation of inflammatory factors and microglia in the cerebral cortex and hippocampus through the brain-gut axis. While reducing the expression of inflammatory factors in the hippocampus and cerebral cortex, thereby controlling neuroinflammation.

CONCLUSION

The imbalance of the gut microbiota and metabolites plays a role in the progression of AD; β-glucan blocks the development of AD by improving the gut microbiota and its metabolites and reducing neuroinflammation. β-Glucan is a potential strategy for the treatment of AD by reshaping the gut microbiota and improving its metabolites.

Yeast beta-glucan mediates histone deacetylase 5-induced angiogenesis in vascular endothelial cells

The role of yeast-derived β-glucan in angiogenesis has not been elucidated because there have been few specific studies on its clinical and physiological significance. Therefore, this study investigated the correlation between β-glucan and histone deacetylase 5 (HDAC5) in human umbilical vein endothelial cells (HUVECs), revealing the role of β-glucan in angiogenesis. We confirmed that HDAC5 was phosphorylated by β-glucan stimulation and released from the nucleus to the cytoplasm. Furthermore, we found that β-glucan-stimulated HDAC5 translocation mediates the transcriptional activation of MEF2. As a result, the expression of KLF2, EGR2, and NR4A2, whose expression is MEF2-dependent and involved in angiogenesis, increased. Thus, we showed the activity of β-glucan in angiogenesis through in vitro and ex vivo assays including cell migration, tube formation, and aortic ring analyses. Specifically, application of an HDAC5 inhibitor repressed MEF2 transcriptional activation in both in vitro and ex vivo angiogenesis. HDAC5 inhibitor LMK235 inhibited the proangiogenic activity of beta-glucan, suggesting that β-glucan induces angiogenesis through HDAC5. These findings suggest that HDAC5 is essential for angiogenesis, and that β-glucan induces angiogenesis. In conclusion, this study demonstrates that β-glucan induces angiogenesis through HDAC5. It also suggests that β-glucan has potential value as a novel therapeutic agent for modulating angiogenesis.

Yeast β-1,3-glucan production by an outer membrane β-1,6-glucanase: process optimization, structural characterization and immunomodulatory activity

The β-glucan from Saccharomyces cerevisiae is a potent adjuvant that exhibits a broad spectrum of biological activities and health benefits, and different processes have been established to prepare active β-glucan from yeast. However, studies concerning the effect of β-1,6-glucanase enzymolysis on the structure and immunomodulatory activity of yeast β-1,3-glucan are scarce. In this study, we aim to develop a novel enzymatic process for the preparation of immunologically active β-glucan (BYG) from baker's yeast using a β-1,6-glucanase GluM. The β-1,6-glucan in fungal cell wall was specifically hydrolyzed by GluM, and resulted in cell wall decomposition and β-glucan release. Batch production of BYG was realized with 17.8% yield, 85.3% purity and 75.4% recovery rate. Structural characterization indicated that BYG exhibits rod-like structures with natural triplex and nanoparticle-like substructures compared with the commercial Glucan 300. BYG ameliorated inflammation in a DSS-induced mouse model of colitis through inhibiting oxidative stress (NO, MDA and MPO), inflammatory mediators (NLRP3, ASC, caspase-1, iNOS and COX-2), and pro-inflammatory cytokines (IL-1β, IL-6, TNF-α, IFN-γ), increasing the expression levels of tight junction proteins (ZO-1, occludin and claudin-1) and modulating the production of gut microbiota-synthesized SCFAs compared to the control. Our results showed that yeast β-1,3-glucan prepared with β-1,6-glucanase exhibits structural integrity that is responsible for its favorable immunomodulatory activity.

β-Glucans as Dietary Supplement to Improve Locomotion and Mitochondrial Respiration in a Model of Duchenne Muscular Dystrophy

Duchenne muscular dystrophy (DMD) is a severe X-linked neuromuscular childhood disorder that causes progressive muscle weakness and degeneration. A lack of dystrophin in DMD leads to inflammatory response, autophagic dysregulation, and oxidative stress in skeletal muscle fibers that play a key role in the progression of the pathology. β-glucans can modulate immune function by modifying the phagocytic activity of immunocompetent cells, notably macrophages. Mitochondrial function is also involved in an important mechanism of the innate and adaptive immune responses, owing to high need for energy of immune cells. In the present study, the effects of 1,3-1,6 β-glucans on five-day-old non-dystrophic and dystrophic (sapje) zebrafish larvae were investigated. The effects of the sonication of β-glucans and the dechorionation of embryos were also evaluated. The results showed that the incidence of dystrophic phenotypes was reduced when dystrophic embryos were exposed to 2 and 4 mg L^-1 of 1,3-1,6 β-glucans. Moreover, when the dystrophic larvae underwent 8 mg L^-1 treatment, an improvement of the locomotor performances and mitochondrial respiration were observed. In conclusion, the observed results demonstrated that 1,3-1,6 β-glucans improve locomotor performances and mitochondrial function in dystrophic zebrafish. Therefore, for ameliorating their life quality, 1,3-1,6 β-glucans look like a promising diet supplement for DMD patients, even though further investigations are required.

Spent Brewer's Yeast as a Source of Insoluble β-Glucans

In the brewing process, the consumption of resources and the amount of waste generated are high and due to a lot of organic compounds in waste-water, the capacity of natural regeneration of the environment is exceeded. Residual yeast, the second by-product of brewing is considered to have an important chemical composition. An approach with nutritional potential refers to the extraction of bioactive compounds from the yeast cell wall, such as β-glucans. Concerning the potential food applications with better textural characteristics, spent brewer’s yeast glucan has high emulsion stability and water-holding capacity fitting best as a fat replacer in different food matrices. Few studies demonstrate the importance and nutritional role of β-glucans from brewer’s yeast, and even less for spent brewer’s yeast, due to additional steps in the extraction process. This review focuses on describing the process of obtaining insoluble β-glucans (particulate) from spent brewer’s yeast and provides an insight into how a by-product from brewing can be converted to potential food applications.

Particulate β-glucan activates early and delayed phagosomal maturation and autophagy within macrophage in a NOX-2 dependent manner

AIMS

Macrophage is known to readily engulf any particulate material they encounter, including invading microbes and nano- or micro-particles. While recent studies show that some microparticles (MP) are immunogenic even without drug-cargo, the mechanism underlying this phenomenon is yet unclear. Phagocytosis induces NADPH oxidase-2 (NOX-2) mediated ROS generation that is reported to regulate antibacterial autophagy. We therefore, investigated the role of NOX-2 derived ROS in phagosomal maturation and autophagy induction in response to phagocytic uptake of two kinds of polymeric biodegradable and biocompatible microparticles: yeast-derived β-glucan particles (YDGP) and poly-(D, L-Lactic Acid) microparticles (PMP).

MAIN METHODS

J774A.1 macrophage wereas exposed to polymeric particles and the immune responses: ROS, phagosomal maturation and autophagy induction, were examined by assays including NBT, DCFH-DA, NADPH-Oxidase activity, Lysotracker and Acridine Orange. Further, the LC3 and NOX-2 expression were validated by RT-PCR, immunofluorescence assay and Western blotting. Antimicrobial activity of both MP was examined by CFU counting after administration to Mycobacterium tuberculosis and Salmonella typhimurium infected macrophage.

KEY FINDINGS

YDGP induces phagosomal maturation and acidic vesicle accumulation at 30 min and 24 h post-exposure, much more proficiently than that by PMP. YDGP exposure also induced NOX-2 dependent expression of light chain 3 (LC3-II), further confirmed as autophagy activation via autophagic flux assay with autophagolysosome inhibitor bafilomycin A1. Additionally, YDGP displayed superior anti-microbial activity than that by PMP.

SIGNIFICANCE

The induction of NOX-2-dependent autophagy and antimicrobial activity exhibited by particulate glucans has significant implications in harnessing these drug delivery vehicles as potential 'value-added' autophagy-mediated therapeutics in future.

Self-Assembling β-Glucan Nanomedicine for the Delivery of siRNA

We aimed to design and manufacture a transporter capable of delivering small interfering RNAs (siRNAs) into the skin without causing any damage. β-glucans are unique chiral polysaccharides with well-defined immunological properties and supramolecular wrapping ability. However, the chiral properties of these polymers have hardly been applied in drug delivery systems. In this study, β-glucan nanoparticles were designed and manufactured to deliver genetic material to the target cells. The β-glucan molecules were self-assembled with an siRNA into nanoparticles of 300–400 nm in diameter via a conformational transition process, in order to construct a gene delivery system. The assembled gene nanocarriers were associated with high gene-loading ability. The expression and efficiency of siRNA were verified after its delivery via β-glucan. Our results provide evidence that β-glucan nanoparticles can be effectively used to deliver siRNA into the cells.

Training of Primary Chicken Monocytes Results in Enhanced Pro-Inflammatory Responses

Beta-glucan-stimulated mammalian myeloid cells, such as macrophages, show an increased responsiveness to secondary stimulation in a nonspecific manner. This phenomenon is known as trained innate immunity and is important to prevent reinfections. Trained innate immunity seems to be an evolutionary conserved phenomenon among plants, invertebrates and mammalian species. Our study aimed to explore the training of primary chicken monocytes. We hypothesized that primary chicken monocytes, similar to their mammalian counterparts, can be trained with β-glucan resulting in increased responses of these cells to a secondary stimulus. Primary blood monocytes of white leghorn chickens were primary stimulated with β-glucan microparticulates (M-βG), lipopolysaccharide (LPS), recombinant chicken interleukin-4 (IL-4) or combinations of these components for 48 h. On day 6, the primary stimulated cells were secondary stimulated with LPS. Nitric oxide (NO) production levels were measured as an indicator of pro-inflammatory activity. In addition, the cells were analyzed by flow cytometry to characterize the population of trained cells and to investigate the expression of surface markers associated with activation. After the secondary LPS stimulation, surface expression of colony stimulating factor 1 receptor (CSF1R) and the activation markers CD40 and major histocompatibility complex class II (MHC-II) was higher on macrophages that were trained with a combination of M-βG and IL-4 compared to unstimulated cells. This increased expression was paralleled by enhanced NO production. In conclusion, this study showed that trained innate immunity can be induced in primary chicken monocytes with β-glucan, which is in line with previous experiments in mammalian species. Innate immune training may have the potential to improve health and vaccination strategies within the poultry sector.

Synthesis, Characterization, and Biological Activity of Aminated Zymosan

Zymosan (ZM), a naturally occurring insoluble macromolecule obtained from the cell wall of Saccharomyces cerevisiae, is used as a functional food (as dietary fiber), phagocytic stimulus, and immune potentiator. The present study aimed to increase its solubility and evaluate its immunological application. ZM was converted into soluble 6-amino-6-deoxy-β-(1-3)-glucan of a molecular weight of 296 kDa by reduction. Detailed structural characterization of aminated ZM was determined by Fourier transform infrared spectroscopy and two-dimensional NMR analysis (2D, COSY, TOCSY, ROSEY, NOSEY, and HSQC). Aminated ZM was biocompatible with Raw 264.7 macrophage cell lines up to a concentration of 100 μg/mL. Rhodamine tagging revealed that the aminated ZM microparticles were found localized within the nucleus of Raw 264.7 cells. Both native and aminated ZM showed a similar expression pattern of inflammatory genes in Raw 264.7.

Beta-glucan's varying structure characteristics modulate survival and immune-related genes expression from Vibrio harveyi-infected Artemia franciscana in gnotobiotic conditions

β-Glucans have long been used as an immunostimulant in aquaculture. However, the relationship of its structure to its immunomodulatory properties are poorly understood. In this study, the particle size and chemical structure of β-glucans extracted from wild-type strain of baker's yeast (Saccharomyces cerevisiae) and its null-mutant yeasts Gas1 were characterised. Using Sigma β-glucan as a reference, the immunomodulatory properties of these polysaccharides in the germ-free Artemia franciscana model system in the presence of Vibrio harveyi bacterial challenge were investigated. The survival of the A. franciscana nauplii, upon challenge with V. harveyi, was significantly higher in all three glucan-treated groups compared to the control. The glucan Gas1 with a lower degree of branching and shorter side chain length had the most prominent V. harveyi-protective effects. The particle size did not affect the nauplii survival when challenged with V. harveyi. Results also showed that the salutary effect of the tested glucans was associated with the upregulation of innate immune genes such as lipopolysaccharide and β-1,3-glucan-binding protein (lgbp), high mobility group box protein (hmgb), and prophenoloxidase (proPO). Interestingly, the up-regulation of superoxidase dismutase (sod) and glutathione-s-transferase (gst) was only observed in Gas1 treated group, indicating that Gas1 could function to induce higher reactive oxygen species and stronger immunomodulatory function in A. franciscana, and therefore higher survival rate. The expression of heat shock protein 70 (hsp70), peroxinectin (pxn), and down syndrome cell adhesion molecule (dscam) remain unaltered in response to glucan treatment. Taken together, this study provides insights into the structure-function relationship of β-glucan and the results confirmed that β-glucan can be an effective immunostimulant in aquaculture, especially the Gas1 glucan.

INVESTIGATION OF THE STRUCTURE OF WATER-SOLUBLE GLUCAN YEAST SACCHAROMYCES CEREVISIAE

It is known that a well-functioning immune system is important for human health. There are many natural and synthetic preparation that are widely used as immunomodulators. One such natural preparat is β-glucan. Beta-glucans are a group of natural polysaccharides. They are recognized as an effective immunocorrector. Their use is advisable both for the prevention of immunodeficiency pathologies and for the complex treatment of many diseases from cardiovascular to oncological. The physiological activity of β-glucan depends on the type and configuration between monosaccharide residues, branching and conformation of macromolecules, solubility in water. One major source of β-glucan is the baker’s yeast Saccharomyces cerevisiae. Much research has been carried out over the years examining cell wall glucans from Saccharomyces cerevisiae. This work is the development devoted to the characterization of water-soluble beta-glucan obtained as a result of controlled degradation with the enzyme Rovabio Excel AP of glucan cell walls of yeast Saccharomyces cerevisiae. In this study conditions were selected which allow to accumulate the maximum water-soluble fractions with a molecular mass of 1–30 kDa presumably as fractions with a high immunomodulatory effect. The results of the paper show that glucan can be isolated from Saccharomyces cerevisiae in very pure form by the method used in this study. Thus structural analysis gives reliable results. The structural characterization of pure product was performed using the common analytical procedures: enzymes hudrolyses and spectral analyses FTIR, NMR spectroscopy. On the basis of the obtained results it was concluded that  investigated glucan is a (1→3)-β-linked glucose polymer with (1→6)-β-linked side chains with sparsely branched. Further work will concern the physiological effect of water-soluble glucan in comparision to the native glucan. The structural requirements for example for an immunomodulation in humans or animals are still under discussion.

Glucan particles as suitable carriers for the natural anti-inflammatory compounds curcumin and diplacone - Evaluation in an ex vivo model

Natural compounds offer a wide spectrum of potential active substances, but often they have a poor bioavailability. To increase the bioavailability and bioactivity of the natural anti-inflammatory molecules curcumin and diplacone, we used glucan particles (GPs), hollow shells from Saccharomyces cerevisiae composed mainly of β-1,3-d-glucan. Their indigestibility and relative stability in the gut combined with their immunomodulatory effects makes them promising carriers for such compounds. This study aimed to determine how curcumin and diplacone, either alone or incorporated in GPs, affect the immunomodulatory activity of the latter by assessing the respiratory burst response and the secretion of pro-inflammatory cytokines by primary porcine innate immune cells. Incorporating curcumin and diplacone into GPs by controlled evaporation of the organic solvent substantially reduced the respiratory burst response mediated by GPs. Incorporated curcumin in GPs also reduced GPs mediated secretion of IL-1β and TNF-α by innate immune cells. The obtained results indicate a potentially beneficial effect of the incorporation of curcumin or diplacone into GPs against inflammation.

Carbohydrate Conjugates in Vaccine Developments

Vaccines are powerful tools that can activate the immune system for protection against various diseases. As carbohydrates can play important roles in immune recognition, they have been widely applied in vaccine development. Carbohydrate antigens have been investigated in vaccines against various pathogenic microbes and cancer. Polysaccharides such as dextran and β-glucan can serve as smart vaccine carriers for efficient antigen delivery to immune cells. Some glycolipids, such as galactosylceramide and monophosphoryl lipid A, are strong immune stimulators, which have been studied as vaccine adjuvants. In this review, we focus on the current advances in applying carbohydrates as vaccine delivery carriers and adjuvants. We will discuss the examples that involve chemical modifications of the carbohydrates for effective antigen delivery, as well as covalent antigen-carbohydrate conjugates for enhanced immune responses.

Encapsulation of poorly soluble drugs in yeast glucan particles by spray drying improves dispersion and dissolution properties

In this work, novel amorphous solid dispersions based on yeast glucan particles were produced. Yeast glucan particles are hollow and porous, and they are mainly composed of amorphous polysaccharides. We hypothesized that these particles are suitable candidates for the amorphization of drugs with low water solubility. Model drugs ibuprofen and curcumin were successfully encapsulated in glucan particles by spray drying. Different spray-drying parameters were tested to evaluate the influence of atomizing droplet size and initial solid content on encapsulation efficiency. It was shown that higher solid content and, more significantly, larger droplet sizes lead to higher encapsulation efficiencies. The encapsulation efficiency of ibuprofen (10 wt%) into glucan particles was considerably improved from 41.3 ± 0.5% to 64.3 ± 0.2% by increasing initial solid content and droplet size with the two-fluid nozzle. The spray drying process was further optimized by using the ultrasonic nozzle and it was possible to achieve complete encapsulation of ibuprofen and curcumin without any precipitation of the active compound outside of the glucan particles. Overall, it was possible to produce completely amorphous composites with outstanding wettability and dispersion properties, and with significantly faster dissolution rates when compared to the micronized crude drug.

Effect of the Modifications on the Physicochemical and Biological Properties of β-Glucan-A Critical Review

β-Glucan exhibits many biological activities and functions such as stimulation of the immune system and anti-inflammatory, anti-microbial, anti-infective, anti-viral, anti-tumor, anti-oxidant, anti-coagulant, cholesterol-lowering, radio protective, and wound healing effects. It has a wide variety of uses in pharmaceutical, cosmetic, and chemical industries as well as in food processing units. However, due to its dense triple helix structure, formed by the interaction of polyhydroxy groups in the β-d-glucan molecule, it features poor solubility, which not only constrains its applications, but also inhibits its physiological function in vivo. One aim is to expand the applications for modified β-glucan with potential to prevent disease, various therapeutic purposes and as health-improving ingredients in functional foods and cosmetics. This review introduces the major modification methods required to understand the bioactivity of β-glucan and critically provides a literature survey on the structural features of this molecule and reported biological activity. We also discuss a new method to create novel opportunities to exploit maximally various properties of β-glucan, namely ultrasound-assisted enzymatic modification.

β-glucan as a new tool in vaccine development

Vaccination constitutes one of the major breakthroughs in human medicine. At the same time, development of more immunogenic vaccine alternatives to using aluminium-based adjuvants is one of the most important phases of vaccination development. Among different sources of carbohydrate polymers, including plants, microbes and synthetic sources tested, glucans were found to be the most promising vaccine adjuvant, as they alone stimulate various immune reactions including antibody production without any negative side effects. The use of glucan particles as a delivery system is a viable option based on the documented efficient antigen loading and receptor-targeted uptake in antigen-presenting cells. In addition to particles, soluble glucans can be used as novel hydrogels or as direct immunocyte-targeting delivery systems employing novel complexes with oligodeoxynucleotides. This review focuses on recent advances in glucan-based vaccine development from glucan-based conjugates to a glucan-based delivery and adjuvant platform.

Characterization and emulsifying properties of extracts obtained by physical and enzymatic methods from an oenological yeast strain

BACKGROUND

Glycosylated compounds are one of the main fractions of the yeast cell wall. Thanks to their amphiphilic structure, they have been studied as stabilizers in food emulsions over a broad range of pH conditions with encouraging results. Nevertheless, extraction costs still represent an important limit for their application in the food industry.

RESULTS

In this research, four extraction methods were applied to yeast cells exploiting both physical (heating and sonication) and enzymatic approaches (use of three industrial enzyme preparations, namely Glucanex®, Sur Lies and Elevage). A fifth method involving a pure β-glucanase enzyme (Zymolyase) was taken as reference. These extraction methods were applied to the oenological strain Saccharomyces cerevisiae EC1118, and their extraction yields and chemical properties (quantitative and qualitative determination of sugars and proteins) were studied. Emulsifying activities were determined at three different pH values (3, 5 and 7). Extractions with Physical, Glucanex and Sur Lies methods were the most successful approaches to obtain relevant amounts of yeast compounds with good emulsifying activities for 2:1 oil-in-water emulsions at pH 3 and 7 over 48 h.

CONCLUSIONS

These results indicate that there is the potential for the extraction approaches here proposed to become viable tools for the recovery of yeast compounds to be used as emulsifiers in foods. This approach can be considered as the starting point to explore the possibility to exploit yeast by-products from the fermentation processes (e.g. fermentation lees from wine and beer making) as valuable compounds for food applications. © 2019 Society of Chemical Industry.

Paramylon, a Potent Immunomodulator from WZSL Mutant of Euglena gracilis

β-glucans, heterogeneous glucose polymers present in many organisms, have the capability to activate the innate immune system. Efficacy of activation depends on purity of the compound, molecular structure, polymerization degree, and source. One of the purest forms of crystallized β-(1–3)-glucan present in nature is the paramylon extracted from the WZSL non-chloroplastic mutant of Euglena gracilis, which can be processed to produce linear nanofibers capable of interacting with specific receptors present on cell membranes. The effects of these nanofibers, already investigated on plants, animals, and humans, will be analyzed.

Structure and Immunomodulatory Activity of Microparticulate Mushroom Sclerotial β-Glucan Prepared from Polyporus rhinocerus

In this study, an immunologically active novel microparticulate mushroom β-glucan (PRA-1p) was prepared using an alkali-soluble glucan PRA-1 by an emulsification and cross-linking method. PRA-1 was a hyperbranched (1→3),(1→6)-β-d-glucan with a degree of branching of 0.89, isolated from the sclerotia of Polyporus rhinocerus. PRA-1 had a rod-like conformation, while PRA-1p exhibited a monodisperse and homogeneous spherical conformation with a diameter ranging from 0.3 to 2.0 μm in water. PRA-1p significantly induced nitric oxide and reactive oxygen species production as well as morphological changes of murine macrophages (RAW 264.7 cells) and upregulated their phagocytic activity. Furthermore, PRA-1p treatment markedly enhanced the secretion of cytokines, including cutaneous T cell-attracting chemokine 27, granulocyte-colony-stimulating factor, monocyte chemoattractant protein 1, macrophage inflammatory protein 1α, macrophage inflammatory protein 2, regulated on activation, normal T cell expressed and secreted, soluble tumor necrosis factor receptor 1, and tissue inhibitors of metalloproteinases. Activation of RAW 264.7 cells triggered by PRA-1p was associated with activation of inducible nitric oxide synthase, nuclear factor κB, extracellular signal-regulated kinase, and protein kinase B. This work suggests that novel PRA-1p derived from the mushroom sclerotia of P. rhinocerus has potential application as an immunostimulatory agent.

Glucan and Mannan-Two Peas in a Pod

In recent decades, various polysaccharides isolated from algae, mushrooms, yeast, and higher plants have attracted serious attention in the area of nutrition and medicine. The reasons include their low toxicity, rare negative side effects, relatively low price, and broad spectrum of therapeutic actions. The two most and best-studied polysaccharides are mannan and glucan. This review focused on their biological properties.

Nano-Rifabutin entrapment within glucan microparticles enhances protection against intracellular Mycobacterium tuberculosis

Recently, yeast-derived glucan particles (GP) have emerged as novel drug delivery agents that provide for receptor-mediated uptake by phagocytic cells expressing β-glucan receptors. In our previous study, we prepared GP loaded with high payload (40.5 + 1.9%) of rifabutin (RB) nano-particles [(RB-NPs)-GP]. We investigated the anti-mycobacterial efficacy and cellular activation responses within Mycobacterium tuberculosis (M. tuberculosis) infected J774 macrophage cells following exposure to the (RB-NPs)-GP formulation. The exposure was seen to augment a robust innate immune response including the induction of reactive oxygen and nitrogen species, autophagy and apoptosis within M. tuberculosis infected macrophage. Further, the efficacy testing of these particles in murine macrophage exhibited that the (RB-NPs)-GP formulation enhanced the efficacy of RB drug by ∼2.5 fold. The study suggests that the set of innate responses conducive to killing intracellular bacteria evoked by (RB-NPs)-GP play a pivotal role in impeding the intracellular M. tuberculosis survival, resulting in enhanced efficacy of the formulation. Our results establish that the (RB-NPs)-GP formulation not only activate M. tuberculosis infected, immune-suppressed macrophage, but also adds significantly to the efficacy of loaded drug, and thus forms a promising approach that should be explored further as an alternative or adjunct form of TB therapy. Highlights Nano-Rifabutin loaded Glucan microparticles [(RB-NPs)-GP] administered to M. tuberculosis infected macrophage. (RB-NPs)-GP induces appropriate innate immune responses in host macrophage. Mycobactericidal Effect of Rifabutin was markedly enhanced by its nano-entrapment in GP. Intracellular drug delivery supplements the innate response in M. tuberculosis infected macrophage.

Candida utilis ATCC 9950 Cell Walls and β(1,3)/(1,6)-Glucan Preparations Produced Using Agro-Waste as a Mycotoxins Trap

Mycotoxins are harmful contaminants of food and feed worldwide. Feed additives with the abilities to trap mycotoxins are considered substances which regulate toxin transfer from feed to tissue, reducing its absorption in animal digestive tract. Market analysis emphasizes growing interest of feed producers in mycotoxins binders obtained from yeast biomass. The aim of the study was to prescreen cell walls (CW) and β(1,3)/(1,6)-glucan (β-G) preparations isolated from Candida utilis ATCC 9950 cultivated on waste potato juice water with glycerol as adsorbents for aflatoxin B1 (AFB1), zearalenone (ZEN), ochratoxin A (OTA), deoxynivalenol (DON), nivalenol (NIV), T-2 toxin (T-2) and fumonisin B1 (FB1). The adsorption was studied in single concentration tests at pH 3.0 and 6.0 in the presence of 1% of the adsorbent and 500 ng/mL of individual toxin. Evaluated CW and β-G preparations had the potential to bind ZEN, OTA and AFB1 rather than DON, NIV, T-2 toxin and FB1. The highest percentage of adsorption (about 83%), adsorption capacity (approx. 41 µg/ g preparation) and distribution coefficient (458.7mL/g) was found for zearalenone when CW preparation was used under acidic conditions. Higher protein content in CW and smaller particles sizes of the formulation could influence more efficient binding of ZEN, OTA, DON and T-2 toxin at appropriate pH compared to purified β-G. Obtained results show the possibility to transform the waste potato juice water into valuable Candida utilis ATCC 9950 preparation with mycotoxins adsorption properties. Further research is important to improve the binding capacity of studied preparations by increasing the active surface of adsorption.

Yeast glucan particles enable intracellular protein delivery in Drosophila without compromising the immune system

Glucan particles spread through the whole organism quickly, accumulate in sites of macrophage occurrence and can deliver cargo into the macrophages with a negligible effect on immune response activation.

Use of β-glucan from spent brewer's yeast as a thickener in skimmed yogurt: Physicochemical, textural, and structural properties related to sensory perception

Powdered β-glucan extracted from brewer's yeast (Yestimun, Leiber GmbH, Bramsche, Germany) was incorporated into skimmed-milk yogurt at varying concentrations (0.2-0.8% wt/wt) to investigate its potential application as a thickener. The effect of β-glucan fortification on the nutritional profile, microstructure, physicochemical properties, and texture of freshly prepared yogurts was investigated. Sensory evaluation was also conducted and was correlated with instrumental analysis. The addition of Yestimun significantly reduced the fermentation time of the yogurt mix from 4 h to 3 h. Scanning electron microscopy revealed that β-glucan particles formed small spherical clusters within the yogurt matrix. The majority of the physicochemical properties (syneresis, viscosity, color, and titratable acidity) remained unaffected by the incorporation of Yestimun in the recipe. Textural properties showed a gradual increment with increasing β-glucan concentration. Hardness, total work done, adhesive force, and adhesiveness increased by 19.27, 23.3, 21.53, and 20.76%, respectively, when using the highest amount of Yestimun powder. Sensory analysis (n = 40) indicated that fortifying yogurt with Yestimun at 0.8% (wt/wt) concentration may affect overall acceptance ratings, which was attributed to adverse flavor and aftertaste effects. However, the overall liking score of the yogurt (5.0/9.0) shows potential for commercialization of the product.

Synthesis of chitin-glucan-aldehyde-quercetin conjugate and evaluation of anticancer and antioxidant activities

In the present study, we have synthesized chitin-glucan-aldehyde-quercetin (chi-glu-ald-que) conjugate via condensation reaction. Synthesis of chitin-glucan-aldehyde (chi-glu-ald) complex was facilitated by the oxidation of chitin-glucan (chi-glu) complex. Formation of conjugate was confirmed by Proton nuclear magnetic resonance spectroscopy (¹H NMR) and Fourier-transform infrared spectroscopy (FT-IR). Morphological studies showed that after grafting of quercetin, several changes on surface were depicted and a more crystalline nature was observed. The chi-glu-ald-que conjugate displayed strong antioxidant activity. It showed 69% of 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical, DPPH* scavenging activity at 1 mg/mL and 72% of 2, 2-azinobis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical cation, ABTS*⁺ scavenging activity at 1 mg/mL concentration, which are much higher than that of chi-glu complex. The anticancer activity of chi-glu-ald-que conjugate was performed in Macrophage cancer cell lines (J774) and biocompatibility was performed in Peripheral blood mononuclear cells (PBMCs). The chi-glu-ald-que conjugate showed excellent cytotoxicity against J774 cell lines but no cytotoxicity towards PBMCs.

An environment-friendly approach to isolate and purify glucan from spent cells of recombinant Pichia pastoris and the bioactivity characterization of the purified glucan

While the methylotrophic yeast Pichia pastoris enables the industrial-scale biosynthesis of many recombinant products, large amount of nutrient-rich biomass emerged along this process. Polysaccharides, especially glucans that are abundant in the cell wall of P. pastoris, are yet to be better utilized owing to their various biological activities. However, the isolation and purification of cell wall glucan from P. pastoris has not been reported. In this study, we established an environment-friendly approach, including induced autolysis, hot-water treatment, ultrasonication, isopropanol extraction, and protease treatment, to isolate and purify glucan from the cell wall of P. pastoris. We achieved a purity of 85.3% and a yield of 11.7% for the purified glucan. Proteins, nucleic acids, lipids, and ash were efficiently removed during the purification. The activities of the purified glucan were investigated in mice fed with a high-fat diet. The purified glucan decreased the level of total cholesterol and triglycerides by 30.3 and 29.7%, respectively. This result suggested that the cell wall glucan of P. pastoris could be developed to a therapeutic agent for dyslipidemia. Our study proposed an environment-friendly and effective method to isolate and purify the glucan from P. pastoris, providing solid foundation for the high-value utilization of this yeast.

Gamma-irradiated β-glucan modulates signaling molecular targets of hepatocellular carcinoma in rats

β-glucans are one of the most abundant forms of polysaccharides known as biological response modifiers which influence host's biological response and stimulate immune system. Accordingly, this study was initiated to evaluate irradiated β-glucan as a modulator for cellular signaling growth factors involved in the pathogenesis of hepatocellular carcinoma in rats. Hepatocellular carcinoma was induced with 20 mg diethylnitrosamine/kg BW. Rats received daily by gastric gavage 65 mg irradiated β-glucan/kg BW. It was found that treatment of rats with diethylnitrosamine induced hepatic injury and caused significant increase in liver injury markers with a concomitant significant increase in both hepatic oxidative and inflammatory indices: alpha-fetoprotein, interferon gamma, and interleukin 6 in comparison with normal and irradiated β-glucan-treated groups. Western immunoblotting showed a significant increase in the signaling growth factors: extracellular signal-regulated kinase 1 and phosphoinositide 3-kinase proteins in a diethylnitrosamine-treated group while both preventive and therapeutic irradiated β-glucan treatments recorded significant improvement versus diethylnitrosamine group via the modulation of growth factors that encounters hepatic toxicity. The transcript levels of vascular endothelial growth factor A and inducible nitric oxide synthase genes were significantly higher in the diethylnitrosamine-treated group in comparison with controls. Preventive and therapeutic treatments with irradiated β-glucan demonstrated that the transcript level of these genes was significantly decreased which demonstrates the protective effect of β-glucan. Histological investigations revealed that diethylnitrosamine treatment affects the hepatic architecture throughout the significant severe appearance of inflammatory cell infiltration in the portal area and congestion in the portal vein in association with severe degeneration and dysplasia in hepatocytes all over hepatic parenchyma. The severity of hepatic architecture changes was significantly decreased with both β-glucan therapeutic and preventive treatments. In conclusion, irradiated β-glucan modulated signal growth factors, vascular endothelial growth factor A, extracellular signal-regulated kinase 1, and phosphatidylinositol-3-kinase, which contributed to experimental hepatocarcinogenesis.

Preparation and characterization of beta-glucan particles containing a payload of nanoembedded rifabutin for enhanced targeted delivery to macrophages

β-glucan particles (GP) are polymeric carbohydrates, mainly found as components of cell wall fungi, yeast, bacteria and also in cereals such as barley and oat, and have been recently shown to have application in macrophage-targeted drug delivery. The aim of this study was to prepare and characterize GP containing a large payload of Rifabutin (RB), an anti-tuberculosis drug effective against MDR-TB at lower MIC than Rifampicin. GP were prepared from yeast cells by acidic and alkaline extraction were either spray dried or lyophilized, prior to RB loading and alginate sealing. The FTIR and ¹³C-NMR spectra of the GP confirmed a β-(1→3) linked glucan structure, with a triple-helical conformation. The spray dried GP exhibited better characteristics in terms of uniformity, size range (2.9 to 6.1 µm) and more than 75 % particles were below 3.5 μm. The RP-HPLC analysis of spray dried GP revealed drug entrapment and drug loading up to 81.46 ± 4.9 % and ~40.5 ± 1.9 %, respectively, as compared to those dried by lyophilization. Electron microscopy showed nearly spherical and porous nature of GP, and the presence of drug 'nanoprecipitates' filling the pore spaces. The formulation showed adequate thermal stability for pharmaceutical application. The particles were readily phagocytosed by macrophage(s) within 5 min of exposure. Drug release occurred in a sustained manner via diffusion, as the release kinetics best fit for drug release was obtained using Higuchi's equation. Thus, the spray dried GP-based-formulation technology holds promise for enhanced targeted delivery of anti-TB drug(s) to macrophage within a therapeutic window for the clearance of intracellular bacteria.

Feeding of nano scale oats β-glucan enhances the host resistance against Edwardsiella tarda and protective immune modulation in zebrafish larvae

In this study, we prepared and characterized the oats origin of nano scale β-glucan (NBG) and investigated the immunomodulatory properties in zebrafish larvae. Newly prepared NBG (average particle size of 465 nm) was fully soluble in water. Zebrafish larvae survival rate was increased against pathogenic bacteria Edwardsiella tarda, when NBG was added to the water (500 μg/mL) compared to NBG non-exposed controls. Moreover, quantitative real time PCR (qRT-PCR) results showed up-regulation of immune functional genes including TNF-α, IL-1β, β-defensin, lysozyme, IL 10, IL 12 and C-Rel indicating higher survival rate could be due to stronger immunomodulatory function of NBG (500 μg/mL). Thus, non-toxic, water soluble and biodegradable NBG from oats could be considered as the potential immunostimulant for larval aquaculture.

Cellular and molecular effects of yeast probiotics on cancer

The cancer is one of the main causes of human deaths worldwide. The exact mechanisms of initiation and progression of malignancies are not clear yet, but there is a common agreement about the role of colonic microbiota in the etiology of different cancers. Probiotics have been examined for their anti-cancer effects, and different mechanisms have been suggested about their antitumor functions. Nonpathogenic yeasts, as members of probiotics family, can be effective on gut microbiota dysbiosis. Generally safe yeasts have shown so many beneficial effects on human health. Probiotic yeasts influence physiology, metabolism, and immune homeostasis in the colon and contribute to cancer treatment due to possessing anti-inflammatory, anti-proliferative and anti-cancer properties. This study reviews some of the health-beneficial effects of probiotic yeasts and their biological substances like folic acid and β-glucan on cancer and focuses on the possible cellular and molecular mechanisms of probiotic yeasts such as influencing pathogenic bacteria, inactivation of carcinogenic compounds, especially those derived from food, improvement of intestinal barrier function, modulation of immune responses, antitoxic function, apoptosis, and anti-proliferative effects.

The evaluation of β-(1 → 3)-nonaglucoside as an anti-Candida albicans immune response inducer

Synthetically prepared bovine serum albumin (BSA) conjugate of linear β-(1 → 3)-nonaglucoside ligand (G9) has been applied as a biological response immunomodulator in vivo and ex vivo. Active immunization of Balb/c mice revealed effective induction of specific humoral responses in comparison with Candida β-D-glucan and Candida whole cells. Induced post-vaccination serum exhibited a growth-inhibition effect on the multi-azole-resistant clinical strain Candida albicans CCY 29-3-164 in experimental mucocutaneous infection ex vivo. Evaluation of immune cell proliferation and the cytotoxic potential of the G9-ligand has revealed its bioavailability and an immunostimulative effect in vaccination-sensitized Balb/c mice splenocytes and RAW 264.7 macrophages.

Euglena gracilis paramylon activates human lymphocytes by upregulating pro-inflammatory factors

The aim of this study was to verify the activation details and products of human lymphomonocytes, stimulated by different β-glucans, that is Euglena paramylon, MacroGard^®, and lipopolysaccharide. We investigated the gene expression of inflammation-related cytokines and mediators, transactivation of relevant transcription factors, and phagocytosis role in cell-glucan interactions, by means of RT-PCR, immunocytochemistry, and colorimetric assay. Our results show that sonicated and alkalized paramylon upregulates pro-inflammatory factors (NO, TNF-α, IL-6, and COX-2) in lymphomonocytes. A clear demonstration of this upregulation is the increased transactivation of NF-kB visualized by immunofluorescence microscopy. Phagocytosis assay showed that internalization is not a mandatory step for signaling cascade to be triggered, since immune activity is not present in the lymphomonocytes that have internalized paramylon granules and particulate MacroGard^®. Moreover, the response of Euglena β-glucan-activated lymphomonocytes is much greater than that induced by commercially used β-glucans such as MacroGard^®. Our in vitro results indicate that linear fibrous Euglena β-glucan, obtained by sonication and alkaline treatment can act as safe and effective coadjutant of the innate immune system response.

An environmental management industrial solution for the treatment and reuse of mussel wastewaters

In the North-West of Spain, the annual production of mussel is 2×10(6)t (35% of the world). The industrial thermal treatment of mussels generates between 300 and 400L/t wastewaters that are continuously disposed into the sea without previous treatment and or further reuse. These effluents, relatively rich in organic matter (7g glycogen/L and 25g COD/L), contribute to the progressive deterioration of the marine ecosystem. We wish to suggest a biotechnological process, based on a laboratory optimization and industrial pre-scale trials, to transform these industrial effluents into a growth culture medium to produce microbial biomass. Furthermore, this biomass is isolated and treated by different optimized separation and purification processes to produce several bioproducts: 1) single cell protein; 2) cell wall material with a high content in glucans and glycoproteins 3) fractions of 1,3-β-glucans and mannoproteins from yeast cell walls hydrolysis; and 4) a potential antioxidant extract. Finally, the authors propose a scaled process for its industrial application. In consequence, we believe that this work provides an environmentally friendly, eco-designed and profitable solution that allows integrating the mussel industry into the ecosystem in a sustainable way.

Microparticulate β-glucan vaccine conjugates phagocytized by dendritic cells activate both naïve CD4 and CD8 T cells in vitro

Microparticulate β-glucan (MG) conjugated to vaccine antigen has been shown to serve as an effective adjuvant in vivo. To further study antigen presentation by MG:vaccine conjugates, bone marrow-derived dendritic cells (BMDC) were treated with MG conjugated to ovalbumin (OVA), then interacted with splenocytes from DO11.10 transgenic mice expressing an OVA peptide-specific T cell receptor. BMDC treated with MG:OVA induced significantly higher numbers of activated (CD25+CD69+) OVA-specific CD4+ T cells than BMDC treated with OVA alone. BMDC treated with MG:OVA upregulated CD86 and CD40 expression as well as MG alone, indicating that conjugation of OVA does not alter the immunostimulatory capacity of MG. Activation of CD8+ OVA-specific OT-1 cells showed that MG:OVA is also capable of enhancing cross-presentation by BMDC to CD8+ cytotoxic T cells. These results show that MG acts as an adjuvant to enhance antigen presentation by dendritic cells to naïve, antigen-specific CD4 and CD8 T cells.

Orally delivered β-glucans aggravate dextran sulfate sodium (DSS)-induced intestinal inflammation

β-Glucans have beneficial health effects due to their immune modulatory properties. Oral administration of β-glucans affects tumour growth, microbial infection, sepsis, and wound healing. We hypothesized that pre-treatment with orally delivered soluble and particulate β-glucans could ameliorate the development of aggravate dextran sulfate sodium (DSS) induced intestinal inflammation. To study this, mice were orally pre-treated with β-glucans for 14 days. We tested curdlan (a particulate β-(1,3)-glucan), glucan phosphate (a soluble β-(1,3)-glucan), and zymosan (a particle made from Saccharomyces cerevisiae, which contains around 55% β-glucans). Weight loss, colon weight, and feces score did not differ between β-glucan and vehicle treated groups. However, histology scores indicated that β-glucan-treated mice had increased inflammation at a microscopic level suggesting that β-glucan treatment worsened intestinal inflammation. Furthermore, curdlan and zymosan treatment led to increased colonic levels of inflammatory cytokines and chemokines, compared to vehicle. Glucan phosphate treatment did not significantly affect cytokine and chemokine levels. These data suggest that particulate and soluble β-glucans differentially affect the intestinal immune responses. However, no significant differences in other clinical colitis scores between soluble and particulate β-glucans were found in this study. In summary, β-glucans aggravate the course of dextran sulfate sodium (DSS)-induced intestinal inflammation at the level of the mucosa.

An evaluation study of different methods for the production of β-D-glucan from yeast biomass

β-Glucan is a proven beneficial and valuable molecule for human and animal health systems. It can be incorporated as an ingredient in various functional foods and beverages. β-Glucan has been isolated from various biological sources, fungi, mushrooms, algae, plants, and bacteria. The yeast cell wall comprises a suitable target for the extraction and purification of β-glucan. Although there are various extraction techniques, significant differences are observed as the technique used affects the final yield and purity, molecular weight, biological activity, solubility, quality, and other biological and functional properties of the extracted β-glucan. The aim of this review is the evaluation of different extraction methods for the production of β-glucan from yeast biomass. Furthermore, the use of industrial spent yeast waste from breweries and the wine industry for biotechnological β-glucan production and the concept of green wineries and breweries are discussed.