Structural analysis and potential immunostimulatory activity of Nannochloropsis oculata polysaccharides

Effects of using microalgae in poultry diets on the production and quality of meat and eggs: a review

1. This review was conducted to examine the nutritional composition of microalgae and their effects as a feed ingredient in poultry diets, delving into their influence on the production and quality of meat and eggs. Data collection focused on peer-reviewed scientific articles, with no limitation on the temporal horizon.2. Regarding nutritional composition, the collected papers indicated that certain microalgae species have a rich nutritional composition, with approximately 50% of their biomass composed of proteins. They contain a high concentration of EPA and DHA, important fatty acids that are found in low concentrations in conventional feedstuffs, and the presence of carotenoids such as beta-carotene.3. Incorporating microalgae into the diet of poultry can improve performance variables, such as mortality, live weight and feed conversion rate. It promotes benefits in meat and egg quality, with reduced cholesterol, increased EPA and DHA, intensified colour and higher concentration of carotenoids.

Dietary Nannochloropsis oculata ameliorates lead acetate induced reproductive toxicity in Barki rams: NF-κB and cytokines pathways

The study aimed to explore the protective effect of Nannochloropsis oculata (N.oculata) on lead induced reproductive toxicity in rams. Sixteen Barki rams were divided equally in to 4 groups; group A: control, group B: was administered 3 % dietary N. oculate, group C: was gavaged 5 mg/kg/day lead acetate and group D: was supplemented with 3 % dietary N. oculata and gavaged with 5 mg/kg/day lead acetate. The experiment lasted 180 days. Semen and blood samples were obtained. Ejaculates were examined for semen criteria besides, analysis of testosterone. Testicular oxidant/antioxidant markers, cytokines, gene expression of interleukin-6 (IL-6) and nuclear factor Kappa B (NF-κB) were estimated. Alga-treated rams revealed significant upgrades in semen criteria, serum testosterone and reduced glutathione (GSH); meanwhile, downregulation in malondialdehyde (MDA), IL-4, IL-2 as well as gene expressions of IL-6 and NF-κB as compared to other treated groups. However, lead-treated rams showed significant deteriorations in semen criteria and reduced GSH while significant elevations in MDA, IL-4, IL-2 as well as gene expression of IL-6 and NF-κB were noticed than control. Alga supplementation to lead-intoxicated rams significantly upgraded the lead induced alterations that were manifested by improvement in testicular histopathology. In conclusion, the addition of alga mitigated lead induced reproductive toxicity in rams via improving testosterone, oxidant/antioxidant status, semen criteria and reducing inflammatory cytokines.

Positive impacts of Nannochloropsis oculata supplementation on gene expression of immune and antioxidant markers and metabolic profile of Barki sheep in the transition period and lipogenic effects on progeny

Nannochloropsis species should be given priority when it comes to microalgae that should be added to feed since they are suitable for intense culture and have a high concentration of PUFAs (especially EPA), antioxidants, and certain vitamins. This study investigated the possible immune and antioxidant impacts of Nannochloropsis supplementation on Barki ewes during transition period and their newly born lambs. Three weeks prior to the expected time of lambing, the researched ewes were divided into two equal groups of thirty ewes each. The second group, on the other hand, was fed the same base diet as the first group plus 10 g of commercially available Nannochloropsis powder per kg of concentrate, given daily to each ewe's concentrate. Findings revealed that supplementation of ewes with Nannochloropsis significantly up-regulated the expression pattern of immune (NFKB, RANTES, HMGB1, TNF-α, IRF4, TLR7, CLA-DRB3.2, IL1B, IL6, CXCL8, S-LZ, and Cathelicidin), and antioxidant (SOD1, CAT, GPX1, GST, ATOX1, Nrf2 and AhpC/TSA) markers in ewes post-lambing and their newly born lambs. Additionally, mRNA levels of lipogenic (ACACA, FASN SCD, LPL, and BTN1A) markers were significantly up-regulated in lambs from supplemented ewes than control ones. There was a significant increase in the WBCs, Hb, RBc count, serum level of glucose, total protein, triacylglycerol and total cholesterol, GPx, catalase, IL1α and IL6 with significantly decreased serum level of TNF-α and MDA in supplemented ewes after lambing as compared with control ones. There was also a significant increase in WBCs, Hb, RBc count, birth weight and body temperature with significantly decreased in the serum levels of TNF-α and stillbirth of newly born lambs from supplemented ewes as compared to other lambs from control ones.

Synergistic effect of green synthesis magnesium oxide nanoparticles and seaweed extract on improving water quality, health benefits, and disease resistance in Nile tilapia

This study aimed to evaluate the effect of adding liquid extract of algae (Hypnea musciformis, Grateloupia acuminata, and Sargassum muticum) (HGS) and Magnesium oxide nanoparticles (MgO NPs) using this extract to rear water of Oreochromis niloticus, on improving culture water indices, growth performance, digestive enzyme, hemato-biochemical characters, immune, antioxidative responses, and resistance after challenged by Aeromonas hydrophila with specific refer to the potential role of the mixture in vitro as resistance against three strains bacteria (Aeromonas sobria, Pseudomonas fluorescens, P. aeruginosa) and one parasite (Cichlidogyrus tilapia). The first group represented control, HGS0, whereas the other group, HGS5, HGS10, and HGS15 mL-1 of liquid extract, as well as all groups with 7.5 μg mL-1 MgO-NPs added to culture water of O. niloticus, for 60 days. Data showed that increasing levels at HGS 10 and HGS15 mL-1 in to-culture water significantly enhanced growth-stimulating digestive enzyme activity and a significantly improved survival rate of O. niloticus after being challenged with A. hydrophila than in the control group. The total viability, coliform, fecal coliform count, and heavy metal in muscle partially decreased at HGS 10 and HGS15 mL-1 than in the control group. Correspondingly, the highest positive effect on hemato-biochemical indices was noticed at levels HGS 10 and HGS15 mL-1. Fish noticed an improvement in immune and antioxidant indices compared to control groups partially at HGS 10 and HGS15 mL-1. Interestingly, fish cultured in rearing water with the mixture provided downregulated the related inflammatory genes (HSP70, TNF, IL-1β, and IL-8) partially at HGS15 mL-1. In vitro, the mixture showed positive efficiency as an antibacterial and partially antiparasitic at HGS 10 and HGS15 mL-1. This study proposes utilizing a mixture of (HGS) and (MgO-NPs) with optimum levels of 10-15 mL-1 in cultured water to improve water indices, growth, health status, and increased resistance of O. niloticus against bacterial and parasitic infection.

Extraction, structural characterization, and antioxidant activity of polysaccharides from three microalgae

Microalgal polysaccharides have received much attention due to their potential value in preventing and regulating oxidative damage. This study aims to reveal the mechanisms of regulating oxidative stress and the differences in the yield, structure, and effect of polysaccharides extracted from three microalgae: Golenkinia sp. polysaccharides (GPS), Chlorella sorokiniana polysaccharides (CPS), and Spirulina subsalsa polysaccharides (SPS). Using the same extraction method, GPS, CPS, and SPS were all heteropoly- saccharides composed of small molecular fraction: the monosaccharides mainly comprised galactose (Gal). Among the three, SPS had a higher proportion of small molecular fraction, and a higher proportion of Gal; thus it had the highest yield and antioxidant activity. GPS, CPS, and SPS all showed strong antioxidant activity in vitro, and showed strong ability to regulate oxidative stress, among which SPS was slightly higher. From the analysis of gene expression, the Nrf2-ARE signalling pathway was an important pathway for GPS, CPS, and SPS to regulate cellular oxidative stress. This study provides a theoretical foundation for further research on the utilization of microalgae polysaccharides and product development.

Semisynthesis of new sulfated heterorhamnan derivatives obtained from green seaweed Gayralia brasiliensis and evaluation of their anticoagulant activity

Marine green algae produce sulfated polysaccharides with diverse structures and a wide range of biological activities. This study aimed to enhance the biotechnological potential of sulfated heterorhamnan (Gb1) from Gayralia brasiliensis by chemically modifying it for improved or new biological functions. Using controlled Smith Degradation (GBS) and O-alkylation with 3-chloropropylamine, we synthesized partially water-soluble amine derivatives. GBS modification increase sulfate groups (29.3 to 37.5 %) and α-l-rhamnose units (69.9 to 81.2 mol%), reducing xylose and glucose, compared to Gb1. The backbone featured predominantly 3- and 2-linked α-l-rhamnosyl and 2,3- linked α-l-rhamnosyl units as branching points. Infrared and NMR analyses confirmed the substitution of hydroxyl groups with aminoalkyl groups. The modified compounds, GBS-AHCs and GBS-AHK, exhibited altered anticoagulant properties. GBS-AHCs showed reduced effectiveness in the APTT assay, while GBS-AHK maintained a similar anticoagulant activity level to Gb1 and GBS. Increased nitrogen content and N-alkylation in GBS-AHCs compared to GBS-AHK may explain their structural differences. The chemical modification proposed did not enhance its anticoagulant activity, possibly due to the introduction of amino groups and a positive charge to the polymer. This characteristic presents new opportunities for investigating the potential of these polysaccharides in various biological applications, such as antimicrobial and antitumoral activities.

Structural characterization of a polysaccharide from Alhagi honey and its protective effect against inflammatory bowel disease by modulating gut microbiota dysbiosis

The Alhagi honey polysaccharide (AHP) exhibits notable anti-inflammatory, antioxidant, and immunomodulatory properties, positioning it as a promising candidate in traditional Chinese medicine. In this investigation, we successfully isolated and purified a neutral AHP, designated AHPN50-1a, subsequently elucidating its structural attributes. AHPN50-1a was found to have a molecular weight of 1.756 × 106 Da, featuring a structural motif characterized by a recurring (1→6)-α-GlcP linker. To comprehensively evaluate its therapeutic potential, we explored the protective effects of AHPN50-1 in a murine model of dextran sodium sulfate-induced colitis. Administration of AHPN50-1 at doses of 200 and 400 mg/kg/day resulted in improved food intake, increased body weight, and increased colon length in mice with acute colitis. Simultaneously, a reduction in the disease activity index and histological scores was observed. AHPN50-1 effectively mitigated colon tissue damage, down-regulated the expression levels of pro-inflammatory cytokines (IL-1β, IL-6, TNF-α) in colon tissue, restored intestinal microbiota diversity, and concentrations of short-chain fatty acids (SCFAs) of gut microbiota metabolites, thus alleviating intestinal inflammation in mice. In summary, our findings underscore the promise of AHPN50-1 as a valuable nutritional or dietary supplement for the treatment and prevention of inflammatory bowel disease.

Study of the polysaccharide production by the microalgae C-1509 Nannochloris sp. Naumann

Biologically active compounds, including polysaccharides isolated from microalgae, have various properties. Although Nannochloropsis spp. have the potential to produce secondary metabolites important for biotechnology, only a small part of the research on these microalgae has focused on their ability to produce polysaccharide fractions. This study aims to evaluate the physicochemical growth factors of Nannochloropsis spp. microalgae, which ensure the maximum accumulation of polysaccharides, as well as to optimize the parameters of polysaccharide extraction. The optimal nutrient medium composition was selected to maximize biomass and polysaccharide accumulation. The significance of selecting the extraction module and extraction temperature regime, as well as the cultivation conditions (temperature and active acidity value) is emphasized. Important chemical components of polysaccharides responsible for their biological activity were identified.

Structural Analysis and Antioxidant and Immunoregulatory Activities of an Exopolysaccharide Isolated from Bifidobacterium longum subsp. longum XZ01

Bifidobacterium longum subsp. longum XZ01 (BLSL1) is a new strain (isolated from the intestines of healthy people and deposited with the preservation number GDMCC 61618). An exopolysaccharide, S-EPS-1, was successfully isolated from the strain and then systematically investigated for the first time. Some structural features of S-EPS-1 were analyzed by chemical component, HPLC, ultraviolet, infrared, and nuclear magnetic resonance spectrum analyses. These analyses revealed that S-EPS-1 is a neutral heteropolysaccharide with an α-configuration. It contains mainly mannose and glucose, as well as small amounts of rhamnose and galactose. The molecular weight of S-EPS-1 was calculated to be 638 kDa. Several immunoregulatory activity assays indicated that S-EPS-1 could increase proliferation, phagocytosis, and NO production in vitro. In addition, S-EPS-1 could upregulate the expression of cytokines at the mRNA level through TLR4-mediated activation of the NF-κB signaling pathway in RAW 264.7 cells. Finally, S-EPS-1 was demonstrated to exhibit antioxidant activity by ABTS+• scavenging, DPPH• scavenging, and ferric-ion reducing power assays. Furthermore, S-EPS-1 can protect cells from oxidative stress and shows no cytotoxicity. These beneficial effects can be partly attributed to its antioxidant ability. Thus, the antioxidant S-EPS-1 may be applied as a functional food in the future.

Fucoidan from Fucus vesiculosus Inhibits Inflammatory Response, Both In Vitro and In Vivo

Fucoidan has been reported to present diverse bioactivities, but each extract has specific features from which a particular biological activity, such as immunomodulation, must be confirmed. In this study a commercially available pharmaceutical-grade fucoidan extracted from Fucus vesiculosus, FE, was characterized and its anti-inflammatory potential was investigated. Fucose was the main monosaccharide (90 mol%) present in the studied FE, followed by uronic acids, galactose, and xylose that were present at similar values (3.8-2.4 mol%). FE showed a molecular weight of 70 kDa and a sulfate content of around 10%. The expression of cytokines by mouse bone-marrow-derived macrophages (BMDMs) revealed that the addition of FE upregulated the expression of CD206 and IL-10 by about 28 and 22 fold, respectively, in respect to control. This was corroborated in a stimulated pro-inflammatory situation, with the higher expression (60 fold) of iNOS being almost completely reversed by the addition of FE. FE was also capable of reverse LPS-caused inflammation in an in vivo mouse model, including by reducing macrophage activation by LPS from 41% of positive CD11C to 9% upon fucoidan injection. Taken together, the potential of FE as an anti-inflammatory agent was validated, both in vitro and in vivo.

Nutritional and immunological evaluation of Nannochloropsis oculata as a potential Nile tilapia-aquafeed supplement

Nannochloropsis oculata (N. oculata) is a marine microalga containing bioactive compounds and a high omega-3 polyunsaturated fatty acid (ω-3 PUFAs). Therefore, it is very promising for nutraceutical and the functional food industry applications. Three groups of Nile tilapia (forty-five fish/group) were fed on basal diets or diets containing 5% (N5) or 10% (N10) of the microalga N. oculata for seven weeks. Fish growth performance, proximate composition, and lipid (fatty acids/ FAs and lipoproteins) profile were estimated. In addition, the expression pattern of some lipid metabolism and immune-relevant genes were assessed. An enhancement in whole body crude protein and growth indices of Nile tilapia was observed on both the supplemented groups N5 and N10. Higher levels of high-density lipoproteins (HDL); and lower levels of the low-density lipoproteins (LDL) were evident in both supplemented groups, while the cholesterol and triglycerides (TG) levels were similar among groups. Ω-3 PUFAs were the significant FAs profile of tilapia fed on N. oculata-supplemented diets in terms of eicosapentaenoic acid, docosahexaenoic acid, and n3/n6 ratio. Concerning the gene expression pattern, heat-shock protein70, glutathione-S-transferase, glutathione peroxidase, and interleukin-1β (IL-1β) were elevated significantly in both supplemented groups. IL-10 is only upregulated in the N10 group. The lipid metabolism-related gene expression showed downregulation of only fatty acid synthase (FAS) in both supplemented groups, with no statistical changes in Peroxisome proliferator-activated receptor alpha (PPARα). Tumor necrosis factor-α (TNF-α), Transforming growth factor-β1 (TGF-β1), and the apoptotic related genes [caspase3 and Proliferating cell nuclear antigen (PCNA)] showed insignificant changes among groups. The histopathological examination of the intestine, liver, and spleen supports our findings and confirms the benefits and safeness of N. oculata dietary inclusion. Collectively, N. oculata is a very promising nutraceutical for improving fish health and sustainability of aquaculture production.

Water-Soluble Saccharina latissima Polysaccharides and Relation of Their Structural Characteristics with In Vitro Immunostimulatory and Hypocholesterolemic Activities

Brown macroalgae are an important source of polysaccharides, mainly fucose-containing sulphated polysaccharides (FCSPs), associated with several biological activities. However, the structural diversity and structure-function relationships for their bioactivities are still undisclosed. Thus, the aim of this work was to characterize the chemical structure of water-soluble Saccharina latissima polysaccharides and evaluate their immunostimulatory and hypocholesterolemic activities, helping to pinpoint a structure-activity relationship. Alginate, laminarans (F1, neutral glucose-rich polysaccharides), and two fractions (F2 and F3) of FCSPs (negatively charged) were studied. Whereas F2 is rich in uronic acids (45 mol%) and fucose (29 mol%), F3 is rich in fucose (59 mol%) and galactose (21 mol%). These two fractions of FCSPs showed immunostimulatory activity on B lymphocytes, which could be associated with the presence of sulphate groups. Only F2 exhibited a significant effect in reductions in in vitro cholesterol's bioaccessibility attributed to the sequestration of bile salts. Therefore, S. latissima FCSPs were shown to have potential as immunostimulatory and hypocholesterolemic functional ingredients, where their content in uronic acids and sulphation seem to be relevant for the bioactive and healthy properties.

Pressurized Liquid Extraction for the Recovery of Bioactive Compounds from Seaweeds for Food Industry Application: A Review

Seaweeds are an underutilized food in the Western world, but they are widely consumed in Asia, with China being the world’s larger producer. Seaweeds have gained attention in the food industry in recent years because of their composition, which includes polysaccharides, lipids, proteins, dietary fiber, and various bioactive compounds such as vitamins, essential minerals, phenolic compounds, and pigments. Extraction techniques, ranging from more traditional techniques such as maceration to novel technologies, are required to obtain these components. Pressurized liquid extraction (PLE) is a green technique that uses high temperatures and pressure applied in conjunction with a solvent to extract components from a solid matrix. To improve the efficiency of this technique, different parameters such as the solvent, temperature, pressure, extraction time and number of cycles should be carefully optimized. It is important to note that PLE conditions allow for the extraction of target analytes in a short-time period while using less solvent and maintaining a high yield. Moreover, the combination of PLE with other techniques has been already applied to extract compounds from different matrices, including seaweeds. In this way, the combination of PLE-SFE-CO2 seems to be the best option considering both the higher yields obtained and the economic feasibility of a scaling-up approximation. In addition, the food industry is interested in incorporating the compounds extracted from edible seaweeds into food packaging (including edible coating, bioplastics and bio-nanocomposites incorporated into bioplastics), food products and animal feed to improve their nutritional profile and technological properties. This review attempts to compile and analyze the current data available regarding the application of PLE in seaweeds to determine the use of this extraction technique as a method to obtain active compounds of interest for food industry application.

Rheological characterization of the exopolysaccharide produced by Alteromonas macleodii Mo 169

Rheology modifiers are essential additives in numerous products in a variety of industries. Due to environmental awareness, consumer-oriented industries are interested in novel natural rheological agents that can replace synthetic chemicals. In this study, the chemical composition and rheological properties of a novel exopolysaccharide (EPS) produced by Alteromonas macleodii Mo 169 were investigated. It was mainly composed of uronic acids (50 mol%) and total carbohydrates were 17 % sulfated. The EPS viscosity increased with concentration, and a non-Newtonian shear thinning behavior was found for concentrations above 0.1 wt%. The elastic and viscous moduli indicated a weak gel-like structure above 0.4 wt%. It maintained its shear thinning behavior and viscoelastic properties in the presence of NaCl and CaCl₂ for pH range 5-7 and temperatures up to 55 °C. Though the apparent viscosity decreased at pH 3 and 9 and temperatures above 65 °C, the shear thinning behavior was retained. The viscous and viscoelastic properties were recovered after heating (95 °C) and cooling (0 °C), indicating a good thermal stability and recoverability. After high shear force, the solution recovered original rheological properties within few seconds, demonstrating self-healing properties.

Microalgal bioactive metabolites as promising implements in nutraceuticals and pharmaceuticals: inspiring therapy for health benefits

The rapid increase in global population and shrinkage of agricultural land necessitates the use of cost-effective renewable sources as alternative to excessive resource-demanding agricultural crops. Microalgae seem to be a potential substitute as it rapidly produces large biomass that can serve as a good source of various functional ingredients that are not produced/synthesized inside the human body and high-value nonessential bioactive compounds. Microalgae-derived bioactive metabolites possess various bioactivities including antioxidant, anti-inflammatory, antimicrobial, anti-carcinogenic, anti-hypertensive, anti-lipidemic, and anti-diabetic activities, thereof rapidly elevating their demand as interesting option in pharmaceuticals, nutraceuticals and functional foods industries for developing new products. However, their utilization in these sectors has been limited. This demands more research to explore the functionality of microalgae derived functional ingredients. Therefore, in this review, we intended to furnish up-to-date knowledge on prospects of bioactive metabolites from microalgae, their bioactivities related to health, the process of microalgae cultivation and harvesting, extraction and purification of bioactive metabolites, role as dietary supplements or functional food, their commercial applications in nutritional and pharmaceutical industries and the challenges in this area of research.

Graphical abstract

Nannochloropsis oculata supplementation improves growth, immune response, intestinal integrity, and disease resistance of Nile Tilapia

OBJECTIVE

The current study evaluated the potential roles of incorporating Nannochloropsis oculata into the diet of Nile Tilapia Oreochromis niloticus in an 8-week trial.

METHODS

Dietary supplementation of N. oculata was tested at inclusion levels (0% [control], 5% [N5], and 10% [N1]) in triplicate. After the trial, comprehensive fish health indicators were evaluated.

RESULT

N. oculata-supplemented feed had a stimulatory effect on fish body weight, where a significant increase in final weight and specific growth rate was observed in the N10 group compared to the control. Better feed conversion was observed at N5 and N10 compared to control. Organosomatic indices were elevated significantly in the N5 group compared to the N10 and control groups. Serum lysozyme activity was significantly increased in the N10 group compared to N5 and control groups. Levels of IgM were significantly higher in N10 compared to the control and N5 groups, with no significance between the latter. Amylase activity showed a significant enhancement in N10 compared to N5. Both levels of N. oculata preserved hepatic health and antioxidant status. Light and transmission electron microscopy showed that Nile Tilapia fed N. oculata at both levels enhanced intestinal immunity, integrity, and absorptive efficiency. The protecting effect of N. oculata was confirmed against Aeromonas hydrophila challenge, where cumulative mortalities were significantly decreased in N5 and N10 groups compared with the control and more in N10.

CONCLUSION

This work confirmed the different beneficial roles of N. oculata dietary supplementation for a Nile Tilapia balanced diet.

Review of Associated Health Benefits of Algal Supplementation in Cattle with Reference to Bovine Respiratory Disease Complex in Feedlot Systems

Within the Australian beef industry bovine respiratory disease is considered one of the most common disease and costs the industry an average net loss of $1647.53 Australian dollars per animal death to bovine respiratory disease complex (BRD). This is due to the disease overwhelming the animal’s immune system during a period where they experience multiple stressors that consequently increase the animal’s susceptivity to disease. Research into the bioactive compounds commonly found in marine algae is rapidly increasing due to its positive health benefits and potential immune modulating properties. Algal supplementation within previous studies has resulted in improved reproduction potential, growth performance, increases antioxidant activity and decreased proinflammatory cytokine concentrations. Additional research is required to further understand the aetiology of BRD and complete analysis of the bioavailability of these bioactive compounds within marine algae to fully explore the potential of marine algae supplementation.

Physicochemical properties, immunostimulatory and antioxidant activities of a novel polysaccharide isolated from Mirabilis himalaica (Edgew) Heim

Herbal medicines often contain bioactive polysaccharides. However, many medicinal herbs have not been explored for any active saccharides that may play key roles in their bioactivities. Herein, we extracted a novel polysaccharide from Mirabilis himalaica (Edgew) heim (denoted MHHP), a popular medicinal ingredient in traditional medicines. The structural and morphological characteristics of MHHP were measured and elucidated by high-performance gel permeation chromatography, gas chromatography connected with mass spectrometry, Fourier transform infrared and nuclear magnetic resonance spectroscopy as well as scanning electron microscopy. MHHP was homogeneous with a molecular weight of 16.1 kDa, M _w/M _n = 1.33, containing mainly α-d-glucan residues with (1→4)-linkage. The biological activities of MHHP upon proliferation of splenic lymphocyte, activation of related cytokine and production of nitric oxide (NO) in RAW264.7 cells were investigated in vitro. MHHP induced proliferation of mouse spleen lymphocytes and significantly promoted the secretion in TNF-α, IL-6 and NO production in RAW264.7 cells. Meanwhile, MHHP exhibited relatively low antioxidant abilities. Our data suggested that MHHP may have potential immunoregulatory and anti-inflammatory activity, with a moderate antioxidant activity.

Mapping Molecular Recognition of β1,3-1,4-Glucans by a Surface Glycan-Binding Protein from the Human Gut Symbiont Bacteroides ovatus

A multigene polysaccharide utilization locus (PUL) encoding enzymes and surface carbohydrate (glycan)-binding proteins (SGBPs) was recently identified in prominent members of Bacteroidetes in the human gut and characterized in Bacteroides ovatus. This PUL-encoded system specifically targets mixed-linkage β1,3-1,4-glucans, a group of diet-derived carbohydrates that promote a healthy microbiota and have potential as prebiotics. The BoSGBP_MLG-A protein encoded by the BACOVA_2743 gene is a SusD-like protein that plays a key role in the PUL’s specificity and functionality. Here, we perform a detailed analysis of the molecular determinants underlying carbohydrate binding by BoSGBP_MLG-A, combining carbohydrate microarray technology with quantitative affinity studies and a high-resolution X-ray crystallography structure of the complex of BoSGBP_MLG-A with a β1,3-1,4-nonasaccharide. We demonstrate its unique binding specificity toward β1,3-1,4-gluco-oligosaccharides, with increasing binding affinities up to the octasaccharide and dependency on the number and position of β1,3 linkages. The interaction is defined by a 41-Å-long extended binding site that accommodates the oligosaccharide in a mode distinct from that of previously described bacterial β1,3-1,4-glucan-binding proteins. In addition to the shape complementarity mediated by CH-π interactions, a complex hydrogen bonding network complemented by a high number of key ordered water molecules establishes additional specific interactions with the oligosaccharide. These support the twisted conformation of the β-glucan backbone imposed by the β1,3 linkages and explain the dependency on the oligosaccharide chain length. We propose that the specificity of the PUL conferred by BoSGBP_MLG-A to import long β1,3-1,4-glucan oligosaccharides to the bacterial periplasm allows Bacteroidetes to outcompete bacteria that lack this PUL for utilization of β1,3-1,4-glucans.

IMPORTANCE With the knowledge of bacterial gene systems encoding proteins that target dietary carbohydrates as a source of nutrients and their importance for human health, major efforts are being made to understand carbohydrate recognition by various commensal bacteria. Here, we describe an integrative strategy that combines carbohydrate microarray technology with structural studies to further elucidate the molecular determinants of carbohydrate recognition by BoSGBP_MLG-A, a key protein expressed at the surface of Bacteroides ovatus for utilization of mixed-linkage β1,3-1,4-glucans. We have mapped at high resolution interactions that occur at the binding site of BoSGBP_MLG-A and provide evidence for the role of key water-mediated interactions for fine specificity and affinity. Understanding at the molecular level how commensal bacteria, such as prominent members of Bacteroidetes, can differentially utilize dietary carbohydrates with potential prebiotic activities will shed light on possible ways to modulate the microbiome to promote human health.

Extraction Procedure, Characteristics, and Feasibility of Caulerpa microphysa (Chlorophyta) Polysaccharide Extract as a Cosmetic Ingredient

The green alga Caulerpa microphysa, which is native to Taiwan, has a relatively high economic value and a well-developed culture technique, and is used mainly as a foodstuff. Its extract has been shown to exhibit antitumor properties, but the polysaccharide content of the extract and its anti-inflammatory and wound-healing effects and moisture-absorption and -retention capacity remain unknown. Hence, the objective of this study was to evaluate the potential of the polysaccharides in C. microphysa extract (CME) for use in cosmetics. The overall polysaccharide yield from the CME was 73.93% w/w, with four molecular weight fractions. The polysaccharides comprised 59.36 mol% mannose, 27.16 mol% glucose, and 13.48 mol% galactose. In addition, the CME exhibited strong antiallergic, wound-healing, transdermal-delivery, and moisture-absorption and -retention effects. In conclusion, the results suggested that CME potentially has anti-inflammatory and wound-healing effects and a good moisture capacity, which can be used in cosmetic applications.

Nannochloropsis oculata feed additive alleviates mercuric chloride-induced toxicity in Nile tilapia (Oreochromis niloticus)

Using microalgae to alleviate the adverse effects of aquaculture pollutants, including metals, has recently gained much attention. In this context, bioaccumulation, hematological indices, oxidative and antioxidant responses, and histopathological alterations were investigated in Nile tilapia (Oreochromis niloticus) fed with either a control diet or diets containing Nannochloropsis oculata (N. oculata) after exposure to mercuric chloride in order to evaluate the role of this microalgae in protecting against mercury-induced toxicity. Fish exposed to HgCl2 at a dose of ¼ LC50 (0.3 mg/L) (Hg group) for 7-21 days exhibited a significant increase in total mercury concentration with a bioaccumulation pattern of liver>gills>muscle, and a significant decrease in all blood indices except mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), monocyte counts, and neutrophil counts. Malondialdehyde (MDA) levels were significantly increased in the Hg group at all time points relative to the control. Glutathione peroxidase (GPx) activity was significantly increased at days 14 and 21, while catalase (CAT) and GPx activities increased and decreased, respectively, at day 7 compared to the control. Additionally, lysozyme activity and immunoglobulin M (IgM) were significantly decreased in the Hg-exposed group. Severe histopathological alterations were evident in the liver, kidneys, and gills. However, supplementation with N. oculata at a low (5%, 50 g/kg feed) or high (10%, 100 g/kg feed) dose stabilized all parameters and reduced the severity of the histopathological alterations with the high N. oculata diet showing more prominent effects. These results suggest that feeding N. oculata protects Nile tilapia against mercuric chloride-induced toxicity.

Advances in microalgal cell wall polysaccharides: a review focused on structure, production, and biological application

Microalgae have been shown to be useful in several biotechnological fields due to their feasible cultivation and high-value biomolecules production. Several substances of interest produced by microalgae, such as: proteins, lipids, and natural colorants, have already been explored. Based on the continuing demand for new natural molecules, microalgae could also be a valuable source of polysaccharides. Polysaccharides are extremely important in aquaculture, cosmetics, pharmaceutical, and food industries, and have great economic impact worldwide. Despite this, reviews on microalgal polysaccharide production, biological activity, and chemical structure are not abundant. Moreover, techniques of microalgal cultivation, coupled with carbohydrate production, need to be clarified in order to develop forward-looking technologies. The present review provides an overview of the main advances in microalgal cell wall polysaccharide production, as well as their associated potential biological applications and chemical structure. Several studies on future prospects, related to microalgae are presented, highlighting the key challenges in microalgal polysaccharide production.

Characterization of levan produced by a Paenibacillus sp. isolated from Brazilian crude oil

A levan-type fructooligosaccharide was produced by a Paenibacillus strain isolated from Brazilian crude oil, the purity of which was 98.5% after precipitation with ethanol and dialysis. Characterization by FTIR, NMR spectroscopy, GC-FID and ESI-MS revealed that it is a mixture of linear β(2 → 6) fructosyl polymers with average degree of polymerization (DP) of 18 and branching ratio of 20. Morphological structure and physicochemical properties were investigated to assess levan microstructure, degradation temperature and thermomechanical features. Thermal Gravimetric Analysis highlighted degradation temperature of 218 °C, Differential Scanning Calorimetry (DSC) glass transition at 81.47 °C, and Dynamic Mechanical Analysis three frequency-dependent transition peaks. These peaks, corresponding to a first thermomechanical transition event at 86.60 °C related to the DSC endothermic event, a second at 170.9 °C and a third at 185.2 °C, were attributed to different glass transition temperatures of oligo and polyfructans with different DP. Levan showed high morphological versatility and technological potential for the food, nutraceutical, and pharmaceutical industries.

TEMPO/NaClO2/NaOCl oxidation of arabinoxylans

TEMPO-oxidation of neutral polysaccharides has been used to obtain polyuronides displaying improved functional properties. Although arabinoxylans (AX) from different sources may yield polyuronides with diverse properties due to their variable arabinose (Araf) substitution patterns, information of the TEMPO-oxidation of AX on its structure remains scarce. We oxidized AX using various TEMPO:NaClO₂:NaOCl ratios. A TEMPO:NaClO₂:NaOCl ratio of 1.0:2.6:0.4 per mol of Ara gave an oxidized-AX with high molecular weight, minimal effect on xylose appearance, and comprising charged side chains. Although NMR analyses unveiled arabinuronic acid (AraAf) as the only oxidation product in the oxidized-AX, accurate AraA quantification is still challenging. Linkage analysis showed that > 75 % of the β-(1→4)-xylan backbone remained single-substituted at position O-3 of Xyl similarly to native AX. TEMPO-oxidation of AX can be considered a promising approach to obtain arabinuronoxylans with a substitution pattern resembling its parental AX.

Transcriptome Analysis Reveals Possible Immunomodulatory Activity Mechanism of Chlorella sp. Exopolysaccharides on RAW264.7 Macrophages

In this study, the exopolysaccharides of Chlorella sp. (CEP) were isolated to obtain the purified fraction CEP4. Characterization results showed that CEP4 was a sulfated heteropolysaccharide. The main monosaccharide components of CEP4 are glucosamine hydrochloride (40.8%) and glucuronic acid (21.0%). The impact of CEP4 on the immune activity of RAW264.7 macrophage cytokines was detected, and the results showed that CEP4 induced the production of nitric oxide (NO), TNF-α, and IL-6 in a dose-dependent pattern within a range of 6 μg/mL. A total of 4824 differentially expressed genes (DEGs) were obtained from the results of RNA-seq. Gene enrichment analysis showed that immune-related genes such as NFKB1, IL-6, and IL-1β were significantly upregulated, while the genes RIPK1 and TLR4 were significantly downregulated. KEGG pathway enrichment analysis showed that DEGs were significantly enriched in immune-related biological processes, including toll-like receptor (TLR) signaling pathway, cytosolic DNA-sensing pathway, and C-type lectin receptor signaling pathway. Protein–protein interaction (PPI) network analysis showed that HSP90AB1, Rbx1, ISG15, Psmb6, Psmb3, Psmb8, PSMA7, Polr2f, Rpsa, and NEDD8 were the hub genes with an essential role in the immune activity of CEP4. The preliminary results of the present study revealed the potential mechanism of CEP4 in the immune regulation of RAW264.7 macrophages, suggesting that CEP4 is a promising immunoregulatory agent.

Phyco-remediation of swine wastewater as a sustainable model based on circular economy

Pork production has expanded in the world in recent years. This growth has caused a significant increase in waste from this industry, especially of wastewater. Although there has been an increase in wastewater treatment, there is a lack of useful technologies for the treatment of wastewater from the pork industry. Swine farms generate high amounts of organic pollution, with large amounts of nitrogen and phosphorus with final destination into water bodies. Sadly, little attention has been devoted to animal wastes, which are currently treated in simple systems, such as stabilization ponds or just discharged to the environment without previous treatment. This uncontrolled release of swine wastewater is a major cause of eutrophication processes. Among the possible treatments, phyco-remediation seems to be a sustainable and environmentally friendly option of removing compounds from wastewater such as nitrogen, phosphorus, and some metal ions. Several studies have demonstrated the feasibility of treating swine wastewater using different microalgae species. Nevertheless, the practicability of applying this procedure at pilot-scale has not been explored before as an integrated process. This work presents an overview of the technological applications of microalgae for the treatment of wastewater from swine farms and the by-products (pigments, polysaccharides, lipids, proteins) and services of commercial interest (biodiesel, biohydrogen, bioelectricity, biogas) generated during this process. Furthermore, the environmental benefits while applying microalgae technologies are discussed.

Grape pectic polysaccharides stabilization of anthocyanins red colour: Mechanistic insights

Grape pectic polysaccharides-malvidin-3-O- β -d-glucoside binding was studied, aiming to unveil the impact of structural diversity of polysaccharides on anthocyanins-polysaccharides interactions. Polysaccharides were extracted with solutions of imidazole (ISP) and carbonate at 4 °C (CSP-4 °C) and room temperature (CSP-RT) and also recovered from the dialysis supernatant of the remaining cellulosic residue after the aqueous NAOH extraction of hemicellulosic polysaccharides (Sn-CR). Polysaccharides richer in homogalacturonan domains, like those present in the CSP-4 °C fraction had approximately 50-fold higher binding affinity to malvidin-3-O- β-d-glucoside, than polysaccharides with side chains (as ISP and CSP-RT extractable polysaccharides). CSP-4 °C polysaccharides showed a positive effect on malvidin-3-O- β-d-glucoside colour fading. Hydration equilibrium constant of malvidin-3-O- β-d-glucoside in the presence of CSP-4 °C polysaccharides was higher, showing the preferential stabilization of the flavylium cation. The results showed that anthocyanins colour stabilization can be promoted by pectic polysaccharide structures such as those extracted by cold carbonate.

Structural elucidation and interfacial properties of a levan isolated from Bacillus mojavensis

A strain with high exopolysaccharide (EPS) production was isolated from soil and identified as Bacillus mojavensis based on the 16S rRNA gene sequencing and biochemical properties. The EPS produced simultaneously with the growth phase reached a maximum of 22 g/L after attaining a stationary phase with sucrose used as sole carbon source. B. mojavensis EPS (BM-EPS) was recovered, fractionated by ethanol precipitation and analysed by NMR and methylation analyses. The BM-EPS was found to be composed of (β2 → 6)-Fruf residues, characteristic of a levan, with an average molecular weight of 2.3 MDa. A homogeneous micro-porous and rough structure matrix was observed by SEM of the freeze-dried powdered sample. A concentration-dependent water-soluble nature was observed, with good water (5.3 g/g) and oil (36 g/g) holding capacities. The levan displayed good emulsification activity with excellent stability against food grade oil, thus favoring it as a promising emulsifying agent to food industries.

Structural Characterization of Quinoa Polysaccharide and Its Inhibitory Effects on 3T3-L1 Adipocyte Differentiation

Quinoa is a kind of nutritious food crop with anti-obesity activity, however, the mechanism is not unclear. In this study, we separated and purified bioactive polysaccharide from quinoa (denoted SQWP-2). The chemical structural was characterized and its effect on 3T3-L1 pre-adipocyte differentiation was evaluated. The molecular weight of SQWP-2 was found to be 7.49 × 103 Da, and the polysaccharide consisted of fructose and glucose. The Glc-(1→, Fru-(2→, →4)-Glcp-(1→, and →4,6)-Glcp-(1→ glycosidic linkages were identified in SQWP-2 through gas chromatography-mass spectrometry. Nuclear magnetic resonance confirmed the monosaccharide composition and glycosidic linkage content, and a suggestion of the structural formula is provided. In Western Blotting and RT-PCR assays, treatment with SQWP-2 significantly inhibited 3T3-L1 differentiation by suppressing PPARγ, C/EBPα, C/EBPβ, C/EBPδ, SREBP1C and AP2 expression. Quinoa polysaccharide isolated here could represent an anti-obesity agent once the structures and differentiation inhibition are definitively characterized.

Structural characteristics of a mannoglucan isolated from Chinese yam and its treatment effects against gut microbiota dysbiosis and DSS-induced colitis in mice

A water-soluble polysaccharide named CYP-1 was isolated from Chinese yam. CYP-1 was characterized as a mannoglucan having a backbone consisting predominately of 1,4-α-linked Glcp branched at O-2, O-3, and O-6 position by t-α-linked Manp with a molecular weight of 2.86 kDa. CYP-1 could inhibit the overproduction of pro-inflammatory cytokines (such as TNF-α and IL-1β) in LPS-induced RAW 264.7 cells and DSS-induced colitis mice. Oral administration of CYP-1 dramatically alleviated colonic pathological damage, suppressed the activation of colonic inflammatory signaling pathways (such as NF-κB and NLRP3 inflammasome), recovered the mRNA expression of junctional proteins (such as ZO-1, claudin-1, occludin, and connexin-43), and modulated the gut microbiota by decreasing the abundances of Alistipes, Helicobacter, and an unidentified Enterobacteriaceae, in DSS-induced colitis mice. Overall, the present study elucidated that a new polysaccharide structure CYP-1 from Chinese yam and its therapeutic potential as a prebiotic for the prevention of inflammatory bowel disease.

Structural characterization and immuno-stimulating activities of a novel polysaccharide from Huangshui, a byproduct of Chinese Baijiu

Huangshui (HS), a byproduct of Baijiu, has been widely studied for the utilization of aromatic compounds and microorganisms. However, there is little information on the bioactive polysaccharides in HS. In this study, a novel complex polysaccharide (HSP-2) composed of mannose, glucose, galactose, arabinose, xylose, and rhamnose at approximate percentages of 53.0, 29.6, 11.5, 2.7, 2.1, and 1.0, respectively, was successfully extracted and purified from HS. The results of FT-IR, methylation analysis, and NMR showed that the backbone of HSP-2 was → 2)-β-D-Manp-(1 → 2,6)-β-D-Manp-(1 → 6)-α-D-Glcp-(1 → 4)-α-L-Rhap-(1 → 3,4)-α-L-Rhap-(1→. In addition, HSP-2 showed significant immuno-stimulating effects via increasing the ROS and NO generation, and enhancing the pinocytic and phagocytic capacities of THP-1 cells in a dose-dependent manner. Meanwhile, HSP-2 treatment increased IFN-γ, TNF-α, IL-6 and IL-1β secretion through activating the expression of the related mRNAs and proteins. These results will provide a molecular basis for immuno-stimulating effects of HSP-2 and lay a foundation for the potential application of HS in functional foods.

Cordyceps sinensis polysaccharide inhibits colon cancer cells growth by inducing apoptosis and autophagy flux blockage via mTOR signaling

Cordyceps sinensis is thought to have anti-cancer effects, but its mechanisms remain elusive. In this study, we aimed to investigate the anti-cancer effect of Cordyceps sinensis polysaccharide (CSP) on human colon cancer cell line (HCT116) and its mechanism. Results indicated that CSP significantly inhibited the proliferation of HCT116 cells, increased autophagy and apoptosis, while blocked autophagy flux and lysosome formation. Further experiments showed that CSP decreased the expression of PI3K and phosphorylation level of AKT and mTOR, increased the expression of AMPKa and phosphorylation level of ULK1. In addition, repression of CSP-induced autophagy by bafilomycin (autophagy inhibitor) enhanced apoptosis and cell death of HCT116 cells. Hence, our findings suggested that CSP inhibited the proliferation of HCT116 cells by inducing apoptosis and autophagy flux blockage, which might be achieved through PI3K-AKT-mTOR and AMPK-mTOR-ULK1 signaling. CSP may be a potential therapeutic agent for colon cancer.