Search Results (281)

Seaweeds are promising third-generation biomass for biobased chemicals, yet their use for lactic acid (LA) production remains underexplored. We evaluated LA production from the dilute-acid hydrolysate of the aquacultured green alga Capsosiphon fulvescens (C.Agardh) Setchell & N.L. Gardner. The dried biomass contained 53.4% carbohydrate (dry-weight basis). HPLC showed a monosaccharide profile enriched in L-rhamnose and D-xylose, with lower levels of D-mannose, D-glucose, D-glucuronolactone, and D-glucuronic acid. Batch fermentations with three Lactobacillus strains revealed clear strain-dependent kinetics and carbon partitioning. Maximum LA titers/yields (time at maximum) were 2.0 g L⁻¹/0.49 g g⁻¹ at 9 h for L. rhamnosus, 2.3 g L⁻¹/0.30 g g⁻¹ at 36 h for L. casei, and 2.8 g L⁻¹/0.23 g g⁻¹ at 48 h for L. brevis; L. rhamnosus achieved the highest yield on sugars consumed, whereas L. brevis reached the highest titer by utilizing a broader sugar spectrum, notably xylose; L. casei showed intermediate performance with limited xylose use. Co-products included acetic and succinic acids (major) and trace 1,2-propanediol and acetaldehyde, consistent with flux through Embden–Meyerhof–Parnas versus phosphoketolase pathways. These results demonstrate that C. fulvescens hydrolysate is a viable marine feedstock for LA production and highlight practical levers—expanding pentose/uronic-acid catabolism in high-yield strains and tuning pretreatment severity—to further improve both yield and titer. Full article

The Altai Republic remains a geographic region with an uncovered microbial diversity hiding yet undescribed potential species. Here, we describe the strain al37.1^T from the Altai soil. It showed genomic similarity with the Bacillus mycoides strain DSM 2048^T. However, the in silico DNA–DNA hybridization (DDH) was 61.6%, which satisfies the accepted threshold for delineating species. The isolate formed circular, smooth colonies, in contrast to the rhizoidal morphology typical of B. mycoides. The strain showed optimal growth under the following conditions: pH 6.5, NaCl concentration 0.5% w/v, and +30 °C. The major fraction of fatty acids was composed of C_16:0 (34.77%), C_18:1 (15.20%), C_14:0 (9.06%), and C_18:0 (7.88%), which were sufficiently lower in DSM 2048^T (C_16:0–15.6%, C_14:0–3.7%). In contrast to DSM 2048^T, al37.1^T utilized glycerol, D-mannose, and D-galactose, while being unable to assimilate D-sorbitol, D-melibiose, and D-raffinose. The strain contains biosynthetic gene clusters (BGCs) associated with the production of fengycin, bacillibactin, petrobactin, and paeninodin, as well as loci coding for insecticidal factors, such as Spp1Aa, chitinases, Bmp1, and InhA1/InhA2. The comparative analysis with the 300 closest genomes demonstrated that these BGCs and Spp1Aa could be considered core for the whole group. Most of the strains, coupled with al37.1^T, contained full nheABC and hblABC operons orchestrating the synthesis of enteric toxins. We observed a cytotoxic effect (≈19 and 22% reduction in viability) of the strain on the PANC-1 cell line. Given the unique morphological features and genome-derived data, we propose a new species, B. altaicus, represented by the type strain al37.1^T. Full article

Dendrobium denneanum Kerr, Dendrobium denneanum Kerr, an orchid in the food-medicine homology catalog, is traditionally used for stomach-nourishing, yin-tonifying, and immunity-enhancing. While its preventive effect on acute gastric ulcers is confirmed, variations among genuine producing areas remain underexplored. This study comparatively analyzed components of D. denneanum from 22 habitats and their polysaccharides’ (DDP) anti-inflammatory/antioxidant activities. Results showed habitat-dependent active components: total sugar (20–51.49%), crude polysaccharide yield (0.29–1.76%), and total phenol (~3%). In vitro, all extracts exhibited dose-dependent scavenging of DPPH (IC₅₀: 0.99–2.11 mg/mL), ABTS (0.61–1.62 mg/mL), and hydroxyl radicals (1.02–2.18 mg/mL), with Habitats 5 and 7 showing the strongest activity. GPC, ion chromatography, and FT-IR revealed DDP had a 5–11 kDa molecular weight, dominated by glucose (49.67–84.73%), plus mannose (8.29–12.25%) and galactose (0.96–16.41%), with shared hydroxyl (3400 cm⁻¹) and β-glycosidic bond (890 cm⁻¹) features. In ethanol-induced gastric ulcer rats, DDP exerted dose-dependent protection: low doses (100 mg/kg/d) reduced ulcer index, increased SOD/GSH-Px (1.5–1.8-fold), decreased MDA (30–35%), and elevated PGE₂; high doses (400 mg/kg/d) further inhibited serum TNF-α/IL-6 (25–40%) and improved histopathology. Conclusion: Despite habitat-dependent component variations, DDP maintains consistent structures. This study first confirms DDP protects gastric mucosa via antioxidant-anti-inflammatory synergism, supporting its development as a natural gastroprotectant. Future work may focus on standardized cultivation and clinical translation. Full article

While numerous bioactive polysaccharides have been identified from mushrooms, their mechanisms of action, particularly through the induction of oxidative stress in tumor cells, remain underexplored. This study isolates a novel polysaccharide, LSPS2, derived from Laetiporus sulphureus, followed by the elucidation of its distinctive structural features and specific antitumor activity in A549 lung carcinoma cells. LSPS2 was composed primarily of glucose (88.1%) and minor amounts of mannose (8.0%) and galactose (3.9%). Methylation and one-dimensional/two-dimensional nuclear magnetic resonance (1D/2D NMR) analysis results indicated that LSPS2 was composed of (1→3)-linked-D-β-glucopyran residues and (1→4)-linked-D-α-glucopyran residues as the main chain. The side chains were connected to O-6 and O-3 of glucopyranose (Glcp) residues with terminal Glcp. It differs from previous reports on L. sulphureus polysaccharides. Functionally, LSPS2 markedly suppressed A549 cell viability in a manner that depended on both exposure duration and concentration. LSPS2 upregulated malondialdehyde (MDA) and downregulated reduced glutathione (GSH), demonstrating that LSPS2 induces oxidative stress in A549 cells. The results of superoxide dismutase (SOD) activity assays further indicated that LSPS2 downregulates SOD activity, which may be the mechanism by which LSPS2 induces oxidative stress and, consequently, apoptosis in A549 cells. This targeted downregulation of a key antioxidant enzyme highlights a potential pathway for polysaccharide-induced tumor cell death. Our findings not only identify LSPS2 as a structurally distinct biopolymer but also elucidate its mode of action, underscoring its prospective application in tumor therapy and functional foods, warranting further investigation. Full article

Sunflower (Helianthus annuus L.) is a cross-pollinated species that relies on pollinators, attracted by itsnectar composition. Nectar consists primarily of sugars (up to 70%), with sucrose, glucose, and fructose being dominant, while minor components such as mannose, arabinose, xylose, and sugar alcohols (e.g., mannitol and inositol) occur in lower concentrations and vary with biotic and abiotic factors. This study developed a robust high-performance liquid chromatography method with refractive index detection (HPLC-RID) for the simultaneous quantification of eight sugars (D-ribose, xylose, arabinose, fructose, mannose, glucose, sucrose, and maltose) and two sugar alcohols (mannitol, meso-inositol) in wild sunflower nectar. A Box–Behnken design (BBD), coupled with response surface methodology (RSM), was used to systematically optimize column temperature (20–23 °C), acetonitrile concentration (80–85%), and flow rate (0.7–1 mL/min), while achieving baseline separation of critical sugar pairs, including the previously co-eluting glucose/mannitol and glucose/mannose. Satisfactory resolution (Rs > 1 for all analytes) was achieved under optimized separation conditions comprising a column temperature of 20 °C, 82.5% acetonitrile, and a flow rate of 0.766 mL/min. The RSM efficiently evaluated factor interactions to maximize chromatographic performance, resulting in an optimized protocol that provides a cost-effective and environmentally friendly alternative to conventional sugar analysis methods. Method validation confirmed satisfactory linearity across relevant concentration ranges (50–500 mg/L for most sugars; 50–5500 mg/L for fructose and glucose), with correlation coefficients (R) between 0.985 and 0.999. The limits of detection (LOD) and quantification (LOQ) for the analyzed sugars and sugar alcohols ranged from 4.04 to 19.46 mg/L and from 13.46 to 194.61 mg/L, respectively. Glucose exhibited the highest sensitivity showing LOD of 4.04 and LOQ of 13.46 mg/L, whereas mannose was identified as the least sensitive analyte, with LOD of 19.46 mg/L and LOQ of 194.61 mg/L. The described method represents a reliable tool for sugar and sugar alcohol analysis in sunflower nectar and can be extended to other plant and food matrices with suitable sample preparation. Full article

Nacre, the iridescent inner layer of mollusk shells, has long been traditionally used in medicine. While we have previously demonstrated its anti-aging effects on muscle and skin, its impact on pancreatic dysfunction and glucose metabolism remains unclear. In this study, we aimed to isolate and identify an active component from nacre extract that improves glucose metabolism and to evaluate its potential to prevent or ameliorate pancreatic dysfunction and glucose metabolic abnormalities in a D-galactose-induced aging mouse model. A polysaccharide component was successfully isolated using a combination of reverse-phase and ion-exchange chromatography. Structural analyses revealed that it was primarily composed of glucose, mannose, and rhamnose, which together accounted for approximately 87% of the total monosaccharide content. Further characterization by FT-IR spectroscopy and MALDI-TOF-MS confirmed its identity as a neutral polysaccharide with glycosidic linkages and an estimated molecular weight of approximately 5000 Da. Intraperitoneal administration of this polysaccharide significantly improved glucose tolerance and prevented a decline in serum insulin levels in D-galactose-induced aging mice. Immunohistochemical analysis of pancreatic tissues revealed that the polysaccharide preserved insulin expression and suppressed the D-galactose-induced upregulation of cellular senescence and apoptosis markers. These findings suggest that this nacre-derived polysaccharide effectively mitigates pancreatic dysfunction and glucose metabolic dysfunction, indicating its potential as a natural therapeutic agent for age-related metabolic disorders. Full article

Peach (Prunus persica (L.)) fruits are abundant in nutrients, with fruit shape and sugar content serving as critical indicators of fruit quality. Melatonin plays a pivotal role in peach fruit development; however, the mechanisms by which it regulates fruit shape development, sugar metabolism, and secondary metabolites remain largely unknown. In this study, peach trees were sprayed with 150 µM melatonin 20 days after pollination. Traditional methods were used to investigate fruit morphology, total soluble solids (TSSs), and titratable acidity content (TAC), while liquid chromatography–mass spectrometry (LC-MS) was employed to analyze sugar metabolites during fruit development. The results indicated that melatonin treatment augmented the transverse and longitudinal diameters of peach fruits by 12% and 6%, respectively, and elevated the contents of soluble solids and titratable acid by 7% and 6%, respectively. The single fruit weight experienced a significant increase of 29.4%, whereas fruit firmness at maturity remained unchanged. Metabolite analysis demonstrated that melatonin decreased the levels of sucrose and D-sorbitol in mature fruits but enhanced the accumulation of D-fructose, L-rhamnose, and xylose. Significantly, melatonin expedited the degradation of galactose, D-mannose, and methyl-D-pyranogalactoside prior to maturity (all three substances naturally decline with fruit ripening), highlighting its role in promoting fruit ripening. In conclusion, exogenous melatonin improves the internal nutrition and flavor quality of fruit by regulating the accumulation of primary and secondary metabolites during fruit ripening. Specifically, the increase in D-fructose (a major contributor to sweetness) and L-rhamnose (a potential precursor for aroma compounds) enhances fruit flavor profile. The accelerated degradation of galactose, D-mannose, and methyl-D-pyranogalactoside (components of cell wall polysaccharides) prior to maturity, alongside the metabolic shift favoring fructose accumulation over sucrose, highlights melatonin’s role in promoting fruit ripening and softening processes. It also promotes fruit enlargement and single fruit weight without affecting fruit firmness. This study establishes a theoretical basis for the further investigation of the molecular mechanisms underlying melatonin’s role in peach fruits and for enhancing quality-focused breeding practices. Full article

Class IId bacteriocins are linear, unmodified antimicrobial peptides produced by Gram-positive bacteria, and often display potent, narrow-spectrum inhibition spectra. Garvicin Q (GarQ) is a class IId bacteriocin produced by the lactic acid bacterium Lactococcus garvieae. It stands out for its unusual broad-spectrum antimicrobial activity against various bacterial species, including Listeria monocytogenes, Pediococcus pentosaceus, Carnobacterium maltaromaticum, Enterococcus faecalis, and Lactococcus spp. Its protein target is the mannose phosphotransferase system (Man-PTS) of susceptible bacterial strains, though little is known about the precise molecular mechanism behind GarQ’s unusual broad spectrum of activity. In this work, ¹³C- and ¹⁵N-labelled GarQ was recombinantly produced using our previously described “sandwiched” protein expression system in Escherichia coli. We also developed a protocol to purify a uniformly labelled sample of the small ubiquitin-like modifier His₆-SUMO, which is produced as a byproduct of the expression procedure. We demonstrated its use as a “free” protein standard for 3D NMR experiment calibrations. The GarQ solution structure was solved using triple-resonance nuclear magnetic resonance (NMR) spectroscopy and was compared with the structures of other Man-PTS-targeting bacteriocins. GarQ adopts a helix–hinge–helix fold, which is contrary to its structural predictions according to AlphaFold 3. Full article

Microbial exopolysaccharides from extreme environments are increasingly becoming valuable candidates for drug development. In this study, four fractions named XL-1, XMRS-1, XL-1-D, and XMRS-1-D were isolated and purified from the hadal bacterium Psychrobacter pulmonis by column chromatography. The structural features of these fractions were characterized by molecular weight, monosaccharide composition, Fourier transform infrared (FTIR) spectrum, amino acid analysis and NMR. The results showed that XL-1 and XMRS-1 were mainly composed of mannose, glucose, and glucosamine, while XL-1-D and XMRS-1-D were mainly composed of mannose. In vitro bioactivity assays demonstrated that all four fractions significantly enhanced RAW264.7 macrophage proliferation and phagocytosis, stimulated nitric oxide (NO) and reactive oxygen species (ROS) production, and induced the secretion of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and the expression of inducible nitric oxide synthase (iNOS) mRNA. Moreover, plate cloning tests, cell scratch tests, and apoptosis assays, along with RT-qPCR analysis, demonstrated that the four fractions significantly inhibited A549 cells’ proliferation. Specifically, XMRS-1 and XMRS-1-D upregulated Bax, Caspase-3, Caspase-8, and Caspase-9, while downregulating Bcl-2, suggesting transcriptional activation of apoptosis-related pathways. These results offered a reference for the further development and utilization of this hadal bacterium in the future. Full article

Objectives: Deoxynivalenol (DON) is a ubiquitous mycotoxin detected in the environment and foodstuffs. DON exposure can lead to chronic intestinal inflammation. Therefore, intervention strategy needs to be established to prevent the intestinal inflammation caused by DON. Methods: The structure of Mesona chinensis Benth polysaccharide-3 (MCP-3), a major component isolated and purified from crude MCP, was analyzed using spectroscopic and chromatographic methods. In vitro assays were conducted on the potential antioxidant bioactivities of MCP-3 and its ameliorative effects on deoxynivalenol-induced oxidative stress in intestinal epithelial cells. Results: Saline-eluted MCP-3 was identified as an acidic heterogeneous polysaccharide with an average molecular weight of 16.014 kDa. Its major monosaccharide components were glucose (20.19%), galactose (11.82%), rhamnose (17.23%), galacturonic acid (29.72%), arabinose (7.11%), xylose (8.09%), mannose (2.79%), and glucuronic acid (3.04%). The main backbone of MCP-3 was composed of the following sequence: →4)-α-D-GalpA-6-(1→4)-α-GalpA-(1→4)-α-D-GalpA-6-(1→2)-α-L-Rhap-(1→4)-α-D-GalpA-6-(1→2,4)-α-L-Rhap-(1→. MCP-3 showed strong antioxidant ability in in vitro assays. It effectively prevented redox imbalance induced by the mycotoxin deoxynivalenol in intestinal epithelial cell models based on Caco-2 and NCM460 cells. MCP-3 significantly increased (p < 0.05) the activities of superoxide dismutase, glutathione peroxidase, and catalase, and significantly decreased (p < 0.05) the levels of malondialdehyde and reactive oxygen species, thereby improving redox homeostasis. Conclusions: MCP-3 has potential as a natural antioxidant for use in functional food and nutraceutical industries to help regulate intestinal oxidative stress caused by mycotoxin DON. Full article

This study aims to identify the chemical structure and immunomodulatory activity of exopolysaccharides (EPSs) from Acetilactobacillus jinshanensis BJ01 and suggest its potential applications in the pharmaceutical field and as functional food additives. The EPS-1 produced by A. jinshanensis BJ01 was purified using column chromatography. The lyophilized powder obtained by vacuum freeze-drying was used for structural characterization and immunomodulatory activity analysis. Gel permeation chromatography (GPC) determined its molecular weight as 156.58 kDa. High-performance anion-exchange chromatography (HPAEC) identified that the EPS-1 is composed of mannose, xylose, and glucose. The structural characterization of EPS-1 by gas chromatography–mass spectrometry (GC-MS) and 1D/2D nuclear magnetic resonance (NMR) spectroscopy demonstrated that EPS-1 is primarily composed of α-D-Manp-(1→, →2,6)-α-D-Manp-(1→, →2)-α-D-Manp-(1→, and →3)-α-D-Manp-(1→. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) illustrated that EPS-1 exhibited a round, flake-like morphology. In vitro experiments with RAW264.7 macrophages demonstrated the high immunomodulatory activity of EPS-1. Significant upregulation of iNOS, IL-6, and TNF-α mRNA levels was confirmed by qRT-PCR (p < 0.05). Western blotting revealed that EPS-1 (6.25 μg/mL) induced phosphorylation of NF-κB (p65, IκBα) and MAPK (ERK) signaling proteins. This study provides the first structural and immunomodulatory characterization of an exopolysaccharide from A. jinshanensis BJ01, highlighting its potential as a novel immune adjuvant. Full article

Background:Salmonella Typhimurium is a major zoonotic pathogen, in which type 1 fimbriae play a crucial role in intestinal colonization and immune modulation. This study aimed to improve the protective immunity of a previously developed growth-deficient strain—a double auxotroph for D-glutamate and D-alanine—by engineering the inducible expression of type 1 fimbriae. Methods: P_tetA-driven expression of the fim operon was achieved by λ-Red mutagenesis. fimA expression was quantified by qRT-PCR, and fimbriation visualized by transmission electron microscopy. Adhesive properties were evaluated through FimH sequence analysis, yeast agglutination, mannose-binding/inhibition assays, and HT-29 cell adherence. BALB/c mice were immunized orogastrically with IRTA ΔΔΔ or IRTA ΔΔΔ P_tetA::fim. Safety and immunogenicity were assessed by clinical monitoring, bacterial load, fecal shedding, ELISA tests, and adhesion/blocking assays using fecal extracts. Protection was evaluated after challenging with wild-type and heterologous strains. Results: IRTA ΔΔΔ P_tetA::fim showed robust fimA expression, dense fimbrial coverage, a marked mannose-sensitive adhesive phenotype and enhanced HT-29 attachment. Fimbrial overexpression did not alter intestinal colonization or translocation to mesenteric lymph nodes (mLNs). Immunization elicited a mixed IgG1/IgG2a, significantly increased IgA and IgG against type 1 fimbriae-expressing Salmonella, and enhanced the ability of fecal extracts to inhibit the adherence of wild-type strains. Upon challenge (IRTA wild-type/20220258), IRTA ΔΔΔ P_tetA::fim reduced infection burden in the cecum (−1.46/1.47-log), large intestine (−1.35/2.17-log), mLNs (−1.32/0.98-log) and systemic organs more effectively than IRTA ΔΔΔ. Conclusions: Inducible expression of type 1 fimbriae enhances mucosal immunity and protection, supporting their inclusion in next-generation Salmonella vaccines. Future work should assess cross-protection and optimize FimH-mediated targeting for mucosal delivery. Full article

In the tumor microenvironment, M2 tumor-associated macrophages play a crucial role in promoting tumor growth, vascularization, and metastasis through their anti-inflammatory and tissue-repairing functions. To reprogram M2 cells into a more benign M1 phenotype and enhance the patient’s intrinsic immune response against cancer, siRNA and small molecules are used, which can be encapsulated into nanoparticles to enhance their stability, circulation time, and bioavailability. Albumin nanoparticles are ideal candidates for the delivery of such cargo because of their low toxicity, biocompatibility, biodegradability, prolonged circulation in the bloodstream, and feasible particle modification. In this study, we optimized a one-step desolvation method using the standard cross-linker glutaraldehyde and D-mannose as a second cross-linker for the synthesis of mannosylated albumin nanoparticles. The obtained nanoparticles demonstrated favorable physical characteristics, high encapsulation efficiency, and the most effective targeting into activated M2 macrophages overexpressing the mannose receptor in comparison to M1 macrophages and cancer cells in vitro. Full article

Immunotherapy is a transformative strategy in oncology, yet the development of novel immunomodulatory agents remains essential. This study explores the anti-tumor potential of a structurally unique polysaccharide isolated from an Aspergillus ochraceus (AOP), sourced from the Antarctic Weddell Sea. Using alkaline-assisted extraction and chromatographic purification, we obtained a homogeneous polysaccharide predominantly composed of galactose and mannose, with an average molecular weight of 39.67 kDa. The structure was characterized by an integrated nuclear magnetic resonance spectroscopy and mass spectrometry analysis, revealing that the AOP is composed of β (1→5)-linked galactofuranose units, with a minor substitution by α-D-mannopyranose residues via (1→2) glycosidic bonds at the C2 of the galactofuranose. Functional assays, including CCK8 and wound-healing tests, demonstrated that this polysaccharide, referred to as AOP, inhibited melanoma cell proliferation and migration in a dose-dependent manner. Additionally, the AOP activated RAW264.7 and bone marrow-derived macrophage (BMDM) cells without exhibiting significant cytotoxicity, leading to the release of inflammatory factors such as TNF-α, IL-1β, and IL-6. Mechanistically, the AOP was found to upregulate the expression of CD86 and IFN-γ, while downregulating genes like IL-4 and Arg1. These findings position the AOP as the first documented Antarctic fungal polysaccharide with macrophage-reprogramming capabilities against melanoma, offering novel molecular insights for marine-derived immunotherapeutics. Full article

Saccharides critically influence tobacco quality. To elucidate the effects of postharvest shading (PS) pre-curing on saccharide metabolic flux, a targeted glycomics analysis was conducted. Compared to light exposure (CK), PS delayed chlorophyll degradation during pre-curing but accelerated yellowing, ultimately resulting in similar pigment levels. Additionally, PS inhibited photosynthesis, leading to reduced starch content and increased soluble sugar content before curing. Furthermore, PS altered the starch-to-sugar conversion, ultimately resulting in significantly higher soluble sugar content and lower starch content. Targeted glycomics analysis identified 21 saccharides, with glucose, D-fructose, and sucrose being dominant. Notably, PS ultimately increased glucose, D-fructose, and sucrose levels by 74.09%, 66.49%, and 17.36%, respectively. Pairwise comparisons revealed 6, 12, 5, 13, 10, and 11 differentially expressed metabolites before curing and at 38, 40, 42, 54, and 68 °C during curing, respectively, between PS and CK. Conjoint analysis identified methylgalactoside and three oligosaccharides (sucrose, raffinose, and maltose) as the central metabolites of saccharide metabolism during curing. D-mannose, D-sorbitol, and D-glucuronic acid were identified as biomarkers for assessing storage-induced metabolic perturbations using random forest algorithms. Collectively, these findings suggest that PS might enhance tobacco quality via carbohydrate metabolism modulation, providing a scientific basis for pre-curing protocol optimization and industrial application. Full article