Surface chemical studies on sphalerite and galena using extracellular polysaccharides isolated from Bacillus polymyxa

Exopolysaccharides of Paenibacillus polymyxa: A review

Paenibacillus polymyxa (P. polymyxa) is a member of the genus Paenibacillus, which is a rod-shaped, spore-forming gram-positive bacterium. P. polymyxa is a source of many metabolically active substances, including polypeptides, volatile organic compounds, phytohormone, hydrolytic enzymes, exopolysaccharide (EPS), etc. Due to the wide range of compounds that it produces, P. polymyxa has been extensively studied as a plant growth promoting bacterium which provides a direct benefit to plants through the improvement of N fixation from the atmosphere and enhancement of the solubilization of phosphorus and the uptake of iron in the soil, and phytohormones production. Among the metabolites from P. polymyxa, EPS exhibits many activities, for example, antioxidant, immunomodulating, anti-tumor and many others. EPS has various applications in food, agriculture, environmental protection. Particularly, in the field of sustainable agriculture, P. polymyxa EPS can be served as a biofilm to colonize microbes, and also can act as a nutrient sink on the roots of plants in the rhizosphere. Therefore, this paper would provide a comprehensive review of the advancements of diverse aspects of EPS from P. polymyxa, including the production, extraction, structure, biosynthesis, bioactivity and applications, etc. It would provide a direction for future research on P. polymyxa EPS.

Microbial weathering of montmorillonite and its implication for Cd(II) immobilization

Interactions between silicate bacteria and silicates are very common in nature and hold great potential in altering their mutual physicochemical properties. But their interactions in regulating contaminants remediation involving performance and mechanisms are often overlooked. Here, we focused on the interactions between silicate bacteria (Paenibacillus polymyxa, PP; Bacillus circulans, BC) and a soil silicate montmorillonite (Mt), and their impact on Cd(II) immobilization. The obtained results showed that Mt greatly promoted the growth of the bacteria, resulting in a maximum 10.31 times increase in biomass production. In return, the bacteria strongly enhanced the Cd(II) adsorption on Mt, with adsorption capacities increased by 80.61%-104.45% in comparison to the raw Mt. Additionally, the bacteria-Mt interaction changed Cd(II) to a more stabilized state with a maximum reduction of 38.90%/g Mt in bioavailability. The enhancement of Cd(II) adsorption and immobilization on the bacterial modified Mt was caused by the following aspects: (1) the bacteria activities altered the aggregation state of Mt and made it better dispersed, thus more active sites were exposed; (2) the microbial activities brought about more rough and crumpled surface, as well as smaller Mt fragments; (3) a variety of microbial-derived functional groups were introduced onto the Mt surface, increasing its affinity for heavy metals; (4) the main Cd(II) immobilization mechanism was changed from ion exchange to the combination of ion exchange and functional groups induced adsorption. This work elucidates the potential ecological and evolutionary processes of silicate bacteria-soil clay mineral interactions, and bears direct implications for the clay-mediated bioremediation of heavy metals in natural environments.

Effect of Ultrasonic Treatment on Structure, Antibacterial Activity of Sugarcane Leaf Polysaccharides

This study investigated the impact of ultrasonic extraction (UE) on the structure and in vitro antibacterial activity of polysaccharides from sugarcane leaves (SLW). Native sugarcane leaf polysaccharides were treated with ultrasound (480 W) for 3 h to yield sugarcane leaf polysaccharides (SLU). Compared to SLW (33.59 kDa), the molecular weight of SLU (13.08 kDa) was significantly decreased, while the monosaccharide composition of SLU was unchanged. The results of SEM and XRD indicated that UE significantly changed the surface morphology of SLW and destroyed its inner crystalline structure. In vitro experiments showed that SLU had stronger antibacterial activity. These findings revealed that UE treatment could alter the tertiary structure of SLW but had no impact on its primary structure. Furthermore, the antibacterial activity of SLW could be greatly enhanced after UE treatment. As a bioactive additive, SLU has great application potential in functional foods, cosmetics, and pharmaceuticals.

A Novel Impedimetric Sensor Based on Cyanobacterial Extracellular Polymeric Substances for Microplastics Detection

Cyanobacterial extracellular polymeric substances "EPS" have attracted intensive concern in biomedicine and food. Nevertheless, the use of those polymers as a sensor coating material has not yet been investigated mainly for microplastic detection. This study focuses on the application of EPS as a sensitive membrane deposited on a gold electrode and investigated with electrochemical impedance spectroscopy to detect four types of microplastics with a size range of 0.1 µm to 1 mm. The surface properties of this impedimetric sensor were investigated by Scanning electron microscopy, Fourier transforms infrared spectroscopy, and X-ray spectroscopy and, showed a high homogenous structure with the presence of several functional groups. The measurements showed a high homogenous structure with the presence of several functional groups. The EPS-based sensor could detect the four tested microplastics with a low limit of detection of 10^-11 M. It is the first report focusing on EPS extracted from cyanobacteria that could be a new quantification method for low concentrations of microplastics.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s10924-022-02555-6.

Extracellular Polymeric Substances Produced by the Thermophilic Cyanobacterium Gloeocapsa gelatinosa: Characterization and Assessment of Their Antioxidant and Metal-Chelating Activities

Cyanobacteria, particularly thermophilic strains, represent an important potential source of EPSs, harboring structural complexity that predicts diverse and specific bioactive potential. The thermophilic cyanobacteria Gloeocapsa gelatinosa, isolated from a natural hot source in Ain Echfa (Tunisia), was cultivated in a cylindrical reactor, and the production of biomass and EPSs was investigated. Results revealed that the strain is amongst the most efficient EPSs producers (0.89 g L⁻¹) and that EPSs production was not correlated with the growth phase. EPSs were sulfated heteropolysaccharides containing carbohydrates (70%) based on nine different monosaccharides, mainly mannose (22%), and with the presence of two uronic acids. EPSs were formed by two polymers moieties with a molecular weight of 598.3 ± 7.2 and 67.2 ± 4.4 kDa. They are thermostable in temperatures exceeding 100 °C and have an anionic nature (zeta potential of −40 ± 2 mV). Atomic force microscopy showed that EPSs formed multimodal lumps with 88 nm maximum height. EPSs presented high water holding capacity (70.29 ± 2.36%) and solubility index (97.43 ± 1.24%), and a strong bivalent metal sorption capacity especially for Cu²⁺ (91.20 ± 1.25%) and Fe²⁺ (75.51 ± 0.71%). The antioxidant activity of G. gelatinosa EPSs was investigated using four methods: the β-carotene-bleaching activity, DPPH assays, iron-reducing activity, and metal-chelating activity. EPS has shown high potential as free radicals’ scavenger, with an IC₅₀ on DPPH (0.2 g L⁻¹) three-fold lower than ascorbic acid (0.6 g L ⁻¹) and as a metal chelating activity (IC₅₀ = 0.4 g L⁻¹) significantly lower than EDTA. The obtained results allow further exploration of the thermophilic G. gelatinosa for several biotechnological and industrial applications.

Towards the Biobeneficiation of PGMs: Reviewing the Opportunities

Conventional beneficiation of the Platinum Group of Metals (PGMs) relies on the use of inorganic chemicals. With the depreciation of high grade deposits, these conventional processes are becoming less economically viable. Furthermore, the use of chemicals has serious negative impacts on the environment. To address the challenges of conventional PGM beneficiation, biobeneficiation has been proposed. In conventional flotation, the flotation behavior of the associated sulphides determines overall PGM recovery. The same principle may also be applied for the bio-beneficiation of PGMs. Therefore, this paper discusses the biobeneficiation behavior of sulphides closely associated with PGMs with the aim of postulating the bio-beneficiation behavior of PGMs associated with the same base metal sulphides. Conventional PGM processes are briefly discussed, as bio-beneficiation of PGMs is governed by similar underlying principles. Potential microorganisms for the biobeneficiation of PGMs are highlighted, as well as the corresponding conditions for their effectiveness. The use of both single cultures and mixed cultures is discussed. Depending on conditions, PGMs associated with pyrite and/or chalcopyrite were projected to be biofloatable with B. polymyxa, P. polymyxa, A. ferrooxidans, L. ferrooxidans, B. pumilus, B. subtilis, halophilic bacteria, Alicyclobacillus ferrooxidans, sulphate reducing bacteria, and mixed cultures of A. ferrooxidans, A. thiooxidans and L. ferrooxidans. Pyrite-associated PGMsare expected to be generally prone to biodepression, whereas chalcopyrite-associated PGMs are expected to be generally recovered as the floatable phase. Sulphate-reducing bacteria were reported to have a dual role on the bioflotation of sulphide ores (flotation and depression), depending on the conditions. Therefore, this type of microorganism may serve as both a depressant or a collector in the recovery of PGMs. Based on the bioflotation response of pyrrhotite to L. ferrooxidans, it is anticipated that pyrrhotite-associated PGMS can be biodepressed using L. ferrooxidans. In terms of bioflocculation, PGMs associated with chalcopyrite may be recovered using L. ferrooxidans, whereas A. ferrooxidans, A. thiooxidans, B. polyxyma and B. subtilis can be used in the bioflocculation of pyrite-associated PGMs. M. phlei can be employed in the reverse bioflocculation of pyrite-associated PGMs. Although no information was found on the biobeneficiation of pentlandite, postulations were made based on other sulphide minerals. It was postulated that biobeneficiation (biodepression and bioflotation) with pentlandite-associated PGMs should be possible using A. ferrooxidans. It is also projected that sulphate-reducing bacteria will be suitable for the bioflotation of PGMs associated with pentlandite. The removal of gangue species such as silicates and chromites associated with PGM concentrates was also discussed. A. ferrooxidans, P. polymyxa and B. mucilaginous are candidates for the removal of gangue species. Furthermore, the need to control process conditions was highlighted. The most suitable conditions for biobeneficiation of the various base metal sulphide minerals associated with PGMs are presented in the paper. Most of the challenges associated with biobeneficiation of PGMs are already common to conventional methods, and the means of circumventing them are already well established. Developments in genetic engineering and the advent of new data science techniques are tools that could make the biobeneficiation of PGMs a possibility.

Physicochemical and phytochemical properties of foam mat dried passion fruit (Passiflora edulis Sims) powder and comparison with fruit pulp

The aim of the present study was to develop purple passion fruit powder using the foam mat dried process. The possible effect of whipping time, methylcellulose concentration, and drying temperature on physicochemical and phytochemical properties of foam mat dried passion fruit was evaluated and compared with fruit pulp. The drying process was optimized using central composite design and optimum conditions were whipping time 2.78 min, methylcellulose 2.58%, temperature 44.05 °C. At the optimum condition vitamin C, total phenolic compound and hygroscopicity were 34.67 mg/100 g, 258.12 mg GAE/100 g, and 21.12%, respectively. The artificial neural network was applied to predict experimental outcomes. The phytochemical properties in terms of (±)-α tocopherol, D-α-tocotrienol, β-carotene, and phenolic acid were determined using RP-HPLC. The foam mate dried powder contained a higher amount of β-carotene (13.26 mg/100 g), total phenolic compound (258.12 mg/100 g) and phenolic acids than fruit pulp whereas fruit pulp was contented higher amount of (±)-α tocopherol (171.1 mg/100 g) and D-α-tocotrienol (27.19 mg/100 g). The study manifested foam mate drying as an effective way to develop passion fruit powder.

First report of a glycosaminoglycan-xylopyranan from the buccinid gastropod mollusk Babylonia spirata attenuating proinflammatory 5-lipoxygenase

A previously undescribed xylated glycosaminoglycan characterized as β-D-Xylop(1 → 3)-(⋯ → 4)-GlcpA(1 → 3)-GlcpNAc(1 → ⋯) was purified from the buccinid gastropod Babylonia spirata and was evaluated for pharmacological properties using different in vitro models. The glycosaminoglycan-xylopyranan displayed prospective free radical quenching activities (IC₅₀  < 0.7 mg/ml), whereas it exhibited potentially greater attenuation against the inductive proinflammatory enzyme 5-lipoxygenase (5-LOX, IC₅₀ 0.36 mg/ml) than the synthetic nonsteroidal anti-inflammatory drug aspirin (0.42). Gel permeation chromatography analysis specified the average molecular mass of the purified polysaccharide to be 231.88 kDa. The linkage sites, anomeric configuration, and the sequence of sugar residues of the purified xylated glycosaminoglycan were attributed by the inter-residue correlation obtained via two-dimensional nuclear resonance spectroscopic techniques. The results specified that the studied compound was composed of GlcpA(1 → 3)-GlcpNAc (1 → ⋯) disaccharide repeating unit in the glycosaminoglycan backbone, with the xylose residues branching as C-3 substituents of the GlcpA. . PRACTICAL APPLICATIONS: The edible marine buccinid mollusk Babylonia spirata is a gastropod species of economic significance in the coastal regions of peninsular India. A previously unreported xylated glycosaminoglycan with a β-D-Xylop(1 → 3)-(⋯ → 4)-GlcpA(1 → 3)-GlcpNAc(1 → ⋯) framework was isolated to homogenity and was found to possess potential antioxidant and 5-lipoxygenase attenuation activities. The isolated metabolite might be anticipated as potential naturally-derived bioactive constituent in functional food and pharmaceutical applications.

Co-production of chondroitin sulfate and peptide from liquefied chicken sternal cartilage by hot-pressure

Co-production of chondroitin sulfate (CS) and peptides was realized from the liquid fraction of chicken sternal cartilage subjected to hot-pressure (HP) by membrane combination separation technology. Cartilage was liquefied via the HP treatment at 110 °C (0.07 MPa) and 120 °C (0.1 MPa) for 0.5 - 2.5 h, respectively. The optimized co-production procedure was as follows: enzymolysis temperature, 61.2 °C; the enzyme ratio of trypsin and papain, 1.3:1 (W/W); enzymolysis time ratio, 2:2 (h/h), under which the highest yields of CS and peptides were 18.85% and 67.99%, and the recoveries were 93.63% and 92.69%. The average molecular weight of CS sample was 67.79 kDa. CS sample was confirmed using agarose-gel electrophoresis, and the structure was analyzed by Fourier transform infrared spectroscopy, chromatography and nuclear magnetic resonance. Taken together, HP can be as a pretreatment method to liquefy cartilage for the industrial co-production of CS and peptides with eco-friendly.

Interfacial Activity and Self-Assembly Behavior of Dissolved and Granular Octenyl Succinate Anhydride Starches

The mechanisms of granular octenyl succinate anhydride (GOSA) and dissolved OSA (DOSA) starches in emulsion stabilization were investigated. In general, DOSA starch offered better emulsification activity by generating greater ζ-potential, lower particle size as well as long-term stability in comparison to GOSA starch of close degree of substitution (DS). A compact interface in DOSA starches was determined, resulting from an increased surface loading value of 2.37 mg/m² in comparison to that of GOSA of 1.6 mg/m². Additionally, the irreversibly adsorbed and predominantly elastic interface of both DOSA and GOSA starches indicated that the DOSA starch may be a Pickering emulsifier rather than a biopolymer surfactant. This assumption was confirmed by transmission electron microscopy. Spherical micelles with average diameters of 100 nm were observed above the critical micelle concentration of 1 mg/mL. Moreover, samples G28 (representing DS of 0.028), D28, G16, and D16 could reach equilibrium interfacial tensions of 19.4, 16.5, 20.0, and 19.3 mN/m, respectively. However, due to the misleading contact angle as a result of rough surfaces and nonignorable gravity of GOSA starch, the energy escape equation failed to be employed in this study.

Inonotus obliquus polysaccharides protect against Alzheimer's disease by regulating Nrf2 signaling and exerting antioxidative and antiapoptotic effects

Inonotus obliquus polysaccharide (IOPS) was initially separated and purified via precipitation from an aqueous extract with 80% alcohol, a DEAE-52 cellulose anion exchange column, and a Sephadex G-100 gel permeation chromatography system. IOPS was found to have a molecular weight of 111.9 kDa. In L-glutamic acid (L-Glu)-damaged HT22 cells, a 3-h pre-incubation with IOPS enhanced cell viability, inhibited apoptosis and caspase-3 activity, reduced the release of lactate dehydrogenase, restored the dissipated mitochondrial membrane potential, and suppressed the excess accumulation of intracellular reactive oxygen species. Compared with L-Glu-exposed cells, IOPS pre-treated cells exhibited reduced levels of Bcl-2 associated X protein (Bax) and Kelch-like ECH-associated protein 1 (Keap1) and enhanced levels of B-cell lymphoma-2 (Bcl-2), NF-E2p45-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), superoxide dismutase-1 (SOD-1), and cysteine ligase catalytic subunit. In amyloid precursor protein/presenilin 1 (APP/PS1) transgenic mice, an 8-week course of IOPS improved the pathological behaviors related to memory and cognition, reduced the deposition of β-amyloid peptides and neuronal fiber tangles induced by enhanced phosphor-Tau in the brain, and modulated the levels of anti- and pro-oxidative stress enzymes. Additionally, IOPS enhanced the expression levels of Nrf2 and its downstream proteins, including HO-1 and SOD-1, in the brains of APP/PS1 mice. The present study successfully demonstrated the protective effect of IOPS against AD and revealed the possible mechanism underlying the ability of IOPS to modulate oxidative stress, especially Nrf2 signaling, and mediate mitochondrial apoptosis.

The characteristic, antioxidative and multiple organ protective of acidic-extractable mycelium polysaccharides by Pleurotus eryngii var. tuoliensis on high-fat emulsion induced-hypertriglyceridemic mice

The antioxidant and multiple organ protection effects of acid- extracted mycelia polysaccharides (Ac-MPS) from Pleurotus eryngii var. tuoliensis on HFE-induced hypertriglyceridemic mice were investigated. The results showed that Ac-MPS have potential ability to relieve the hypertriglyceridemia and preventing oxidative stress by decreasing levels of TG, TC LDL-C, elevating contents of HDL-C in serum, increasing the activities of SOD, GSH-Px, CAT and T-AOC, and the down regulating MDA and LPO contents in liver, heart, kidney and spleen. And the histopathological observations also displayed that Ac-MPS could alleviate organ damage. Moreover, the GC, HPGPC, FT-IR and AFM analyses revealed the Ac-MPS possessed the typical polysaccharides structure with the molecular weights (Mw) of 2.712 × 10⁵ Da. These conclusions indicated that the Ac-MPS had the potential to develop new drugs for hypertriglyceridemia-induced multiple organ failure.

Sulfated polysaccharide isolated from Globularia alypum L.: Structural characterization, in vivo and in vitro anticoagulant activity, and toxicological profile

A sulfated polysaccharide from Globularia alypum L. (GASP) was extracted with a yield of 14.2%. GASP is composed mostly of sulfate and total sugars (13.29% and 71.56%, respectively) with small amount of proteins and lipids. The chemical and structural characterization was studied by Infra-Red spectroscopic and gas chromatography-mass spectrometry (GC-MS). GASP composed of eight carbohydrates where galactose, glucose, and mannose are the major compounds (33.47%, 26.71% and 18.21%, respectively). The in vitro and in vivo anticoagulant activities in rats were tested using the standard coagulation assays activated partial thromboplastin time (aPTT), prothrombine time (TT) and thrombin time (PT) tests. Both doses of GASP (200 and 500 mg/kg b.w) displayed a significant in vitro (1.22 and 1.33-fold, 1.17 and 1.27-fold, and 1.21 and 1.26-fold, respectively) and in vivo (1.47 and 2.52-fold; 1.20 and 1.43-fold; 1.21 and 1.40-fold, respectively) compared with the control. Toxicity studies on liver performed by the catalytic activity of transaminases in plasma, oxidative stress markers and hepatic morphological changes indicated that GASP at both doses are not toxics. The important pharmacological and toxicological profile of GASP revealed that this compound may be used as a novel and effective drug.

Exopolysaccharide from Marine Bacillus velezensis MHM3 Induces Apoptosis of Human Breast Cancer MCF-7 Cells through a Mitochondrial Pathway

Objective: The production of new natural pharmaceutical agents that increase the efficiency of chemotherapy without affecting the normal cells is the goal of all researchers. Therefore, the present study expects to evaluate the antioxidant and anticancer studies against MCF-7 cell lines of EPS produced by novel Egyptian marine bacterial strain. Methods: Marine bacterium was isolated, purified and identified by 16S rRNA gene amplification and sequence analyses. MHMEPS (the produced EPS) was analyzed by Fourier Transform Infra-red (FTIR), monosugars identification by HPLC, molecular weight estimation and sulfur content were determined. While, in-vitro antioxidants characters was determined using various methods and anticancer studies against MCF-7 cell lines. Results: Bacillus velezensis MHM3 produced 5.8 g/L of MHMEPS. The chemical analysis of MHMEPS showed 24% uronic acid and 18.19% sulfate and monosugars glucuronic acid, glucose, fructose and rhamnose with molar ratio of 4.00: 2.00: 1.00: 0.13, correspondingly, with an overall weight average molecular weight Mw of 1.145×104 g/mol and the number average of molecular weights Mn of 5.155 ×103 g/mol. The FTIR analysis and periodate oxidation indicate the existence of β-(1–4) linkage acidic polysaccharide. MHMEPS showed antioxidant scavenging activity against DPPH•, H2O2 and Metal chelating activity, respectively. So, reducing power method give high activity at 500 μg/ml. MHMEPS hinder the proliferation of MCF-7 cells at 5-80 μg/ml compared to the control group. Moreover, induced apoptosis was associated with activation of caspase-3. Also increased cytochrome C levels significantly in a dose-dependent manner compared with the control. The Caspase-3 activity was raised in MHMEPS treated MCF-7 cells compared with the control (p<0.05) in a dose-dependent manner. Therefore, the result of DNA fragmentation was confirmed by DNA ladder assay. We presume that MHMEPS has high potential at its low concentration, as a novel restorative agent for the treatment of MCF-7 cells, with no cytotoxicity against normal cells.

Characterization of a novel polysaccharide isolated from Phyllanthus emblica L. and analysis of its antioxidant activities

Phyllanthus emblica L. is a tropical deciduous tree producing edible berries with potential medicinal value. In this study, a novel water-soluble phyllanthus emblica polysaccharide (PEP) from the berries was isolated by precipitation and purification, and analyzed for its structure features. The results showed that PEP was a α-pyran acidic heteropolysaccharide with a molecular weight of 1.31 × 10⁵ Da, which included galacturonic acid, galactose, rhamnose, and arabinose with a molar ratio of 3.21:6.59:1:0.23. Furthermore, the antioxidant activities of PEP were determined and showed remarkable antioxidant capacities in DPPH, superoxide anion- and hydroxyl-radical scavenging, ferric-reducing antioxidant power, and lipid peroxidation inhibition. This work indicated that PEP as a natural antioxidant agent from the berries of Phyllanthus emblica L. had potential application for developing valuable nutraceutical in food industry.

Isolation, Purification and Structural Characterestics of Chondroitin Sulfate from Smooth hound Cartilage: In vitro Anticoagulant and Antiproliferative Properties

Chondroitin sulfate was extracted from the cartilage of smooth hound (CSSH) and then purified by anion exchange chromatography. The structual characteristic of CSSH was evaluated by acetate cellulose electrophoresis, FTIR, ¹³C NMR and SAX-HPLC. Molecular weight of CSSH was average 68.78 KDa. Disaccharide analysis indicated that CSSH was predominately composed of monosulfated disaccharides in position 6 and 4 of the N-acetylgalactosamine (45.34% and 32.49%, respectively). CSSH was tested for in vitro anticoagulant activity using the three classical coagulation assays (activated partial thromboplastin time (aPTT), prothrombine time (TT) and thrombin time (PT) tests). The finding showed that CSSH prolonged significatively (p < 0.05), aPTT, TT and PT about 1.4, 3.44 and 1.21 fold, respectively, greater than that of the negative control at a concentration of 100 μg/ml. The CSSH caused a significant antiproliferative activity against HCT116 cell, which was 79% of cell proliferation inhibition at the concentration of 1000 μg/ml. Further, CSSH presented no toxicity against the normal cells and no hemolysis towards bovine erythrocytes for all concentrations tested. CSSH demonstrated hopeful antiproliferative and anticoagulant potential, which may be used as a novel and effective drug.

Bioactive potential and structural characterization of sulfated polysaccharides from Bullet tuna (Auxis Rochei) by-products

The present study deals with the isolation of sulfated polysaccharides (Ps) from the Bullet tuna by-products (head, skin and bones). Results of chemical characterization revealed that Ps-bones showed the highest total sugar, uronic acid and sulfate group contents. Tuna extracted-Ps contained a mixture of neutral sugars, with high amounts of glucuronic and galacturonic acids and presented different molecular weights. The presence of sulfate groups in different Ps was confirmed by FTIR analysis. Interestingly, Ps-bones showed the highest antioxidant activity among all the extracted Ps. Moreover, results revealed that all polysaccharides displayed varying degrees of antibacterial activity. Ps-bones exhibited high and wide spectrum of activities, inhibiting the growth of all bacteria tested. Ps-bones incorporated during fillet cooking offered an excellent protection of fish fillet by avoiding pH change, color loss, lipid oxidation and spoilage. Overall, the results demonstrated that Ps could be potentially used as natural antioxidant and antibacterial agents.

Purification and structural elucidation of chondroitin sulfate/dermatan sulfate from Atlantic bluefin tuna (Thunnus thynnus) skins and their anticoagulant and ACE inhibitory activities

Chondroitin sulfate/dermatan sulfate (CS/DS) was extracted from Atlantic bluefin tuna (Thunnus thynnus) skin (SGAT) and was purified and characterized. SGAT was characterized by acetate cellulose electrophoresis, FTIR spectroscopy, ¹³C NMR spectroscopy and SAX-HPLC. According to the results obtained for specific chondroitinases (ABC and AC) and the SAX-HPLC separation of generated unsaturated repeating disaccharides, the polymer was found to contain a disaccharide monosulfated in positions 6 and 4 of GalNAc and disulfated disaccharides in different percentages. These results were confirmed by ¹³C NMR experiments. The average molecular mass was 24.07 kDa, as determined by PAGE analysis. SGAT was evaluated for its in vitro anticoagulant activity via activated partial thromboplastin time, thrombin time and prothrombin time tests. The polymer showed strong inhibitory activity against angiotensin I-converting enzyme (IC₅₀ = 0.25 mg mL⁻¹). Overall, the results suggest that this newly extracted CS/DS can be useful for pharmacological applications.

Chondroitin sulfate/dermatan sulfate (CS/DS) was extracted from Atlantic bluefin tuna (Thunnus thynnus) skin (SGAT) and was purified and characterized.

Studies on the purification of polysaccharides separated from Tremella fuciformis and their neuroprotective effect

The present study aimed to investigate the protective effect of purified polysaccharides from Tremella fuciformis against glutamate-induced cytotoxicity in differentiated PC12 (DPC12) cells. The aqueous extract of Tremella fuciformis was purified using a DEAE-52 cellulose anion exchange column and a Sepharose G-100 column, respectively. A fraction termed TL04 with a 2,033 kDa molecular weight was obtained. The backbone of TL04 is composed of (1→2)‑ and (1→4)-linked-mannose and (1→3)-linked-glucans. Results revealed that TL04 treatment improved cell viability and suppressed reactive oxygen species accumulation, lactose dehydrogenase release and caspase-3 activity, and ameliorated mitochondrial abnormal alteration caused by glutamate. TL04 pretreatment enhanced the level of B‑cell lymphoma 2 (Bcl‑2), and suppressed Bax expression and cytochrome c (Cyto C) release in glutamate-treated cells. Exposure to glutamate strongly increased the activity of caspase‑8, caspase‑9 and caspase‑3, which were significantly reversed by TL04 pretreatment. The presence of Ac-DEVD-CHO (a caspase-3 inhibitor) markedly enhanced the potency of TL04 in improving the viability of glutamate-exposed DPC12 cells. Collectively, the results demonstrated that the purified polysaccharides separated from Tremella fuciformis (TL04) possess a neuroprotective effect against glutamate-induced DPC12 cell damage predominantly through the caspase-dependent mitochondrial pathway. The present study provides an experimental foundation supporting purified TL04 as a potential therapeutic agent for neurodegenerative diseases.

Antioxidant and DNA Damage Protecting Activity of Exopolysaccharides from the Endophytic Bacterium Bacillus cereus SZ1

An endophytic bacterium was isolated from the Chinese medicinal plant Artemisia annua L. The phylogenetic and physiological characterization indicated that the isolate, strain SZ-1, was Bacillus cereus. The endophyte could produce an exopolysaccharide (EPS) at 46 mg/L. The 1,1-diphenyl-2-picrylhydracyl (DPPH) radical scavenging activity of the EPS reached more than 50% at 3-5 mg/mL. The EPS was also effective in scavenging superoxide radical in a concentration dependent fashion with an EC50 value of 2.6 mg/mL. The corresponding EC50 for scavenging hydroxyl radical was 3.1 mg/mL. Moreover, phenanthroline-copper complex-mediated chemiluminescent emission of DNA damage was both inhibited and delayed by EPS. The EPS at 0.7-1.7 mg/mL also protected supercoiled DNA strands in plasmid pBR322 against scission induced by Fenton-mediated hydroxyl radical. The preincubation of PC12 cells with the EPS prior to H₂O₂ exposure increased the cell survival and glutathione (GSH) level and catalase (CAT) activities, and decreased the level of malondialdehyde (MDA) and lactate dehydrogenase (LDH) activity in a dose-dependent manner, suggesting a pronounced protective effect against H₂O₂-induced cytotoxicity. Our study indicated that the EPS could be useful for preventing oxidative DNA damage and cellular oxidation in pharmaceutical and food industries.

The anti-membranous glomerulonephritic activity of purified polysaccharides from Irpex lacteus Fr

The present study aims to identify the major active component from mutant Irpex lacteus, which protects against cationic bovine serum albumin (C-BSA)-induced membranous glomerulonephropathy (MGN). The candidate component ILN3A (MW: 2264 kDa) was purified from mutant Irpex lacteus water extract. The backbone of ILN3A comprises (1→2) and (1→4) linkages, and (1)H NMR spectrum suggests the existence of α- and β-glycosidic anomeric carbon. In tissue culture study, ILN3A inhibits mesangial cell proliferation. In MGN rats, ILN3A reverses structural changes in kidney, suppresses abnormal high level of urine protein and restores concentration of serum albumin. ILN3A also reduces total cholesterol, triglycerides, and creatinine in serum, and 6-keto-PGF in kidney cortex. Further study shows ILN3A restores serum Interleukin 2, Interleukin 2 receptor, Interleukin 6, tumor necrosis factor α, and renal cortical nuclear factor kappa B. Our data shows ILN3A, the major active component of mutant Irpex lacteus, is a novel candidate anti-inflammatory medicine to treat MGN in clinics.

Structural characterization and anti-tumor effects of an inulin-type fructan from Atractylodes chinensis

A fructan (ACPS-1) with a molecular weight of 11.2 kDa was isolated from Atractylodes chinensis rhizome and characterized by chemical derivatization, HPLC, GC-MS, FT-IR, and NMR. Structural analyses revealed that ACPS-1 is predominately composed of fructose and a small amount of glucose and a polymerization degree of about 53. The fructan was deduced to be an inulin-type fructan containing a linear backbone composed of (2→1)-linked β-d-Fruf residues. The in vitro antitumor activity of ACPS-1 was evaluated on four human cancer cell lines, including a cervical cancer cell line (Hela), two liver hepatocellular carcinoma cell lines (HepG2 and 7721), and an ovarian carcinoma cell line (Skov3). Results showed that ACPS-1 could significantly inhibit Hela, HepG2, and 7721 cell proliferation, especially HepG2, for which the fructan showed a proliferative inhibition rate as high as 87.40%. This result suggests that ACPS-1 may have anticancer potentiality against hepatocellular carcinoma and warrants further investigation.

Purification of polysaccharides from Cordyceps militaris and their anti‑hypoxic effect

Acute mountain sickness, one of the most common altitude diseases, causes lung and brain injury. The present study aimed to investigate the anti‑hypoxic effect of purified polysaccharides extracted from Cordyceps militaris. The aqueous extract of Cordyceps militaris was purified progressively through a DEAE‑52 cellulose anion exchange column and a Sepharose G‑100 column. The fraction CMN1, with a molecular weight of 37842 Da, was the main fraction obtained and its chemical composition and structural characteristics were determined. CMN1 was found to have a monosaccharide composition of L‑rhamnose, L‑arabinose, D‑mannose, D‑galactose. The backbone of CMN1 comprised (1→2) and (1→3) linkages, with branched (1→6) and (1→4) linkages. The anti‑hypoxic effects of CMN1 were determined using a sodium nitrite toxicosis test, acute cerebral ischemic/hypoxic test and normobarie hypoxia test. CMN1 (0.5 g/kg) possessed a similar anti‑hypoxic effect to rhodiola oral liquid. Overall, the Cordyceps militaris polysaccharide, CMN1, was identified as an effective agent against hypoxia.

Fermentation technologies for the optimization of marine microbial exopolysaccharide production

In the last decades, research has focused on the capabilities of microbes to secrete exopolysaccharides (EPS), because these polymers differ from the commercial ones derived essentially from plants or algae in their numerous valuable qualities. These biopolymers have emerged as new polymeric materials with novel and unique physical characteristics that have found extensive applications. In marine microorganisms the produced EPS provide an instrument to survive in adverse conditions: They are found to envelope the cells by allowing the entrapment of nutrients or the adhesion to solid substrates. Even if the processes of synthesis and release of exopolysaccharides request high-energy investments for the bacterium, these biopolymers permit resistance under extreme environmental conditions. Marine bacteria like Bacillus, Halomonas, Planococcus, Enterobacter, Alteromonas, Pseudoalteromonas, Vibrio, Rhodococcus, Zoogloea but also Archaea as Haloferax and Thermococcus are here described as EPS producers underlining biopolymer hyperproduction, related fermentation strategies including the effects of the chemical composition of the media, the physical parameters of the growth conditions and the genetic and predicted experimental design tools.