OBJECTIVES: To investigate the therapeutic effects of inulin-type oligosaccharides of Morinda officinalis (IOMO) in a murine model of Streptococcus pneumoniae meningitis (SPM) and explore its possible mechanisms. METHODS: A total of 120 male C57BL/6J mice were randomly assigned into Sham, SPM+Saline, SPM+IOMO (25 mg/kg), and SPM+IOMO (50 mg/kg) groups. After modeling, the mice received daily gavage of saline or IOMO at the indicated doses for 7 consecutive days, and the changes in symptom scores and mortality of the mice were monitored. Brain pathology and neuronal injury of the mice were assessed using HE and Nissl staining, and qRT-PCR was performed to detect mRNA levels of the inflammatory mediators. Brain edema and blood-brain barrier (BBB) permeability of the mice were evaluated by measuring brain water content and Evans blue (EB) staining; Western blotting was used to analyze the expressions of BBB-associated proteins, and flow cytometry was employed to detect IFN‑γ expression level in the infiltrating lymphocytes. Open-field test (OFT) and novel object recognition test (NORT) were conducted to assess learning and memory ability of the mice on day 21 after modeling. RESULTS: IOMO treatment at 50 mg/kg significantly reduced the symptom scores and mortality rate of SPM mice, alleviated brain damage, and downregulated mRNA levels of IL-6, TNF‑α, IL-1β, IL-18, IFN‑γ, iNOS, NLRP3, ASC, caspase-1 and GSDMD in the brain tissue. IOMO treatment also decreased brain water content and EB leakage, upregulated VE-cadherin and occludin expressions, and suppressed AQP4, iNOS, and IFN‑γ levels of the mice. IOMO-treated mice exhibited improved learning and memory compared with the saline-treated mice on day 21 after SPM modeling. CONCLUSIONS IOMO alleviates SPM symptoms, reduces mortality, and mitigates cognitive deficits in mice possibly by suppressing cerebral inflammation and protecting BBB functions.
Animals ; Morinda/chemistry* ; Mice, Inbred C57BL ; Male ; Mice ; Meningitis, Pneumococcal/drug therapy* ; Blood-Brain Barrier/metabolism* ; Inulin/therapeutic use* ; Oligosaccharides/therapeutic use* ; Disease Models, Animal ; Interferon-gamma/metabolism* ; Brain Edema

The high content of sucrose and raffinose reduces the prebiotic value of soybean oligosaccharides. Fructan sucrases can catalyze the conversion of sucrose and raffinose to high-value products such as fructooligosaccharides and melibiose. To obtain a fructan sucrase that can efficiently convert soybean oligosaccharides, we first mined the fructan sucrase gene from microorganisms in the coastal areas of Xisha Islands and Bohai Bay and then characterized the enzymatic and catalytic properties of the enzyme. Finally, recombinant extracellular expression of this gene was carried out in Bacillus subtilis. The results showed that a novel fructan sucrase, BhLS 39, was mined from Bacillus halotolerans. With sucrose and raffinose as substrates, BhLS 39 showed the optimal temperatures of 50 ℃ and 55 ℃, optimal pH 5.5 for both, and K_cat/K_m ratio of 3.4 and 6.6 L/(mmol·s), respectively. When 400 g/L raffinose was used as the substrate, the melibiose conversion rate was 84.6% after 30 min treatment with 5 U BhLS 39. Furthermore, BhLS 39 catalyzed the conversion of sucrose to produce levan-type-fructooligosaccharide and levan. Then, the recombinant extracellular expression of BhLS 39 in B. subtilis was achieved. The co-expression of the intracellular chaperone DnaK and the extracellular chaperone PrsA increased the extracellular activity of the recombinant BhLS 39 by 5.2 folds to 17 U/mL compared with that of the control strain. BhLS 39 obtained in this study is conducive to improving the quality and economic benefits of soybean oligosaccharides. At the same time, the strategy used here to enhance the extracellular expression of BhLS 39 will also promote the efficient recombinant expression of other proteins in B. subtilis.
Oligosaccharides/metabolism* ; Glycine max/metabolism* ; Bacillus subtilis/metabolism* ; Sucrase/biosynthesis* ; Raffinose/metabolism* ; Fructans/metabolism* ; Sucrose/metabolism* ; Bacillus/genetics* ; Recombinant Proteins/biosynthesis* ; Bacterial Proteins/biosynthesis*

The gut microbiota is closely related to human health, and various gut microbiota health indices have been developed to assist in evaluating the health of the gut microbiota and even the overall health of the human body. Diets are one of the main factors that regulate the gut microbiota, while there is still no good method for evaluating the regulatory effects of dietary factors. To assess the regulatory effects of dietary factors on the gut microbiota of overweight individuals, we conducted an in vitro fermentation experiment based on 17 dietary factors, and developed an evaluation method for the regulatory effects of dietary factors based on the health index with principal component analysis (hiPCA). The results showed that most dietary factors had positive regulatory effects on the gut microbiota of overweight individuals. Galactooligosaccharides (GOS) and puerarin were the most significant dietary factors in regulating the gut microbiota of overweight individuals. The analysis of the contribution of species to the hiPCA indicated that GOS and puerarin might inhibit the activities of bacteria associated with overweight by regulating Eubacterium dolichum, Lactobacillus salivarius, Clostridium clostridioforme, Clostridium citroniae, and Lachnospiraceae bacterium 9_1_43BFAA. In addition, GOS may further enhance the inhibition of these activities by regulating Lachnospiraceae bacterium 6_1_63FAA, thereby reducing the gut health risks in overweight individuals. In summary, this study evaluated the health effects of dietary factors based on the hiPCA and specifically analyzed the role of different dietary factors in regulating the gut microbiota of overweight individuals. This provides new ideas and methods for improving gut microbiota health and has potential applications in the field of precision nutrition.
Humans ; Gastrointestinal Microbiome/physiology* ; Isoflavones/pharmacology* ; Overweight/microbiology* ; Diet ; Fermentation ; Oligosaccharides/pharmacology* ; Principal Component Analysis

Poria is an important medical herb in clinic. The authors isolated a polysaccharide(PCP-Ⅰ) from Poria in previous studies, which is composed of galactose, mannose, fucose and glucose. PCP-Ⅰ exhibited significant adjuvant effects on H1N1 influenza vaccine, hepatitis B surface antigen and anthrax protective antigen, and its adjuvant activity was stronger than aluminium adjuvant. However, little is known about the chemical structure of PCP-Ⅰ at present. In this study, weak acid hydrolysis was used to obtain the backbone oligosaccharide of PCP-Ⅰ. Then periodate oxidation, Smith degradation, methylation analysis, Fourier transform infrared spectroscopy(FT-IR), nuclear magnetic resonance(NMR) and gas chromatography-mass spectrometry(GC-MS) were performed to investigate the chemical structural features of PCP-Ⅰ and its hydrolytic oligosaccharide(PCP-Ⅰ-hy-1). These results suggested that the backbone of PCP-Ⅰ was composed of galactose with α anomeric carbon and β anomeric carbon. The linking residues of galactan are(1→),(l→6) and(1→2,6).
Adjuvants, Vaccine ; Poria ; Hydrolysis ; Spectroscopy, Fourier Transform Infrared ; Galactose ; Influenza A Virus, H1N1 Subtype ; Polysaccharides/chemistry* ; Oligosaccharides ; Carbon

Soluble cello-oligosaccharide with 2-6 oligosaccharide units is a kind of oligosaccharide with various biological functions, which can promote the proliferation of intestinal probiotics such as Bifidobacteria and Lactobacillus paracei. Therefore, it has a regulatory effect on human intestinal microbiota. In this study, a Cc 01 strain was constructed by expressing cellodextrin phosphorylase (CDP) in Escherichia coli. By combining with a previously constructed COS 01 strain, a three-enzyme cascade reaction system based on strains COS 01 and Cc 01 was developed, which can convert glucose and sucrose into cello-oligosaccharide. After optimization, the final titer of soluble cello-oligosaccharides with 2-6 oligosaccharide units reached 97 g/L, with a purity of about 97%. It contained cellobiose (16.8 wt%), cellotriose (49.8 wt%), cellotetrose (16.4 wt%), cellopentaose (11.5 wt%) and cellohexose (5.5 wt%). When using inulin, xylo-oligosaccharide and fructooligosaccharide as the control substrate, the biomass (OD₆₀₀) of Lactobacillus casei (WSH 004), Lactobacillus paracei (WSH 005) and Lactobacillus acidophilus (WSH 006) on cello-oligosaccharides was about 2 folds higher than that of the control. This study demonstrated the efficient synthesis of cello-oligosaccharides by a three-enzyme cascade reaction and demonstrated that the synthesized cello-oligosaccharides was capable of promoting intestinal microbial proliferation.
Humans ; Oligosaccharides ; Biomass ; Escherichia coli/genetics* ; Gastrointestinal Microbiome ; Glucose

Sialyllactose is one of the most abundant sialylated oligosaccharides in human milk oligosaccharides (HMOs), which plays an important role in the healthy development of infants and young children. However, its efficient and cheap production technology is still lacking presently. This study developed a two-step process employing multiple-strains for the production of sialyllactose. In the first step, two engineered strains, E. coli JM109(DE3)/ pET28a-BT0453 and JM109(DE3)/pET28a-nanA, were constructed to synthesize the intermediate N-acetylneuraminic acid. When the ratio of the biomass of the two engineered strains was 1:1 and the reaction time was 32 hours, the maximum yield of N-acetylneuraminic acid was 20.4 g/L. In the second step, E. coli JM109(DE3)/ pET28a-neuA, JM109(DE3)/ pET28a-nst and Baker's yeast were added to the above fermentation broth to synthesize 3'-sialyllactose (3'-SL). Using optimal conditions including 200 mmol/L N-acetyl-glucosamine and lactose, 150 g/L Baker's yeast, 20 mmol/L Mg²⁺, the maximum yield of 3'-SL in the fermentation broth reached 55.04 g/L after 24 hours of fermentation and the conversion rate of the substrate N-acetyl-glucosamine was 43.47%. This research provides an alternative technical route for economical production of 3'-SL.
Child ; Humans ; Child, Preschool ; N-Acetylneuraminic Acid ; Escherichia coli/genetics* ; Lactose ; Fermentation ; Saccharomyces cerevisiae ; Oligosaccharides ; Glucosamine

α-amylase is an endonucleoside hydrolase that hydrolyzes the α-1, 4-glycosidic bonds inside polysaccharides, such as starch, to generate oligosaccharides, dextrins, maltotriose, maltose and a small amount of glucose. Due to the importance of α-amylase in food industry, human health monitoring and pharmaceuticals, detection of its activity is widely required in the breeding of α-amylase producing strains, in vitro diagnosis, development of diabetes drugs, and the control of food quality. In recent years, many new α-amylase detection methods have been developed with improved speed and sensitivity. This review summarized recent processes in the development and applications of new α-amylase detection methods. The major principle of these detection methods were introduced, and their advantages and disadvantages were compared to facilitate future development and applications of α-amylase detection methods.
Humans ; alpha-Amylases/chemistry* ; Polysaccharides ; Oligosaccharides ; Starch ; Maltose

Chitosanases represent a class of glycoside hydrolases with high catalytic activity on chitosan but nearly no activity on chitin. Chitosanases can convert high molecular weight chitosan into functional chitooligosaccharides with low molecular weight. In recent years, remarkable progress has been made in the research on chitosanases. This review summarizes and discusses its biochemical properties, crystal structures, catalytic mechanisms, and protein engineering, highlighting the preparation of pure chitooligosaccharides by enzymatic hydrolysis. This review may advance the understandings on the mechanism of chitosanases and promote its industrial applications.
Chitosan/chemistry* ; Chitin ; Glycoside Hydrolases/genetics* ; Protein Engineering ; Oligosaccharides/chemistry* ; Hydrolysis

Alginate is a group of polyuronic saccharides that are widely used in pharmaceutical and food industry due to its unique physicochemical properties and beneficial health effects. However, the low water solubility and high viscosity of alginate hampered its application. Alginate oligosaccharide (AOS) is a decomposition product of alginate and has received increasing attention due to its low molecular weight, high water solubility, safety, and non-toxicity. The wide-ranging biological functions of AOS are closely related to its structural diversity. AOS with distinct structures and biological functions can be obtained by different methods of preparation. This review summarized the biological functions of AOS reported to date, including anti-tumor, immunomodulatory, anti-inflammatory, antioxidant, prebiotic, and anti-diabetes. The preparation of AOS, as well as the relationship between the structure and biological functions of AOS were discussed, with the aim to provide a reference for further development and application of AOS.
Alginates ; Anti-Inflammatory Agents ; Antioxidants ; Molecular Weight ; Oligosaccharides

Most bacterial cell surface glycans are structurally unique, and have been considered as ideal target molecules for the developments of detection and diagnosis techniques, as well as vaccines. Chemical synthesis has been a promising approach to prepare well-defined oligosaccharides, facilitating the structure-activity relationship exploration and biomedical applications of bacterial glycans. L-Galactosaminuronic acid is a rare sugar that has been only found in cell surface glycans of gram-negative bacteria. Here, an orthogonally protected L-galactosaminuronic acid building block was designed and chemically synthesized. A synthetic strategy based on glycal addition and TEMPO/BAIB-mediated C6 oxidation served well for the transformation of commercial L-galactose to the corresponding L-galactosaminuronic acid. Notably, the C6 oxidation of the allyl glycoside was more efficient than that of the selenoglycoside. In addition, a balance between the formation of allyl glycoside and the recovery of selenoglycoside was essential to improve efficiency of the NIS/TfOH-catalyzed allylation. This synthetically useful L-galactosaminuronic acid building block will provide a basis for the syntheses of complex bacterial glycans.
Carbohydrates ; Glycosides ; Oligosaccharides ; Oxidation-Reduction ; Polysaccharides/chemistry*