Polysaccharides: Structure and Solubility

Understanding the solubility of polysaccharides is extremely important for their food applications as most functions of polysaccharides including stability, emulsifying property, drug delivery, membrane forming properties, etc., are all achieved in aqueous solution. This chapter aims specifically at the mechanism of solubility of polysaccharides from the molecular level. General understandings of the solubility including definition, testing methods, and the solution behaviors were provided; the relationships between polysaccharide solubility and the structural features in terms of molecular weight, degree of branching, charging properties, chain flexibility, and the special groups were all discussed. With all the information provided, the molecular modification and further applications of polysaccharides in both food and nonfood areas could be promoted

Production of Exopolysaccharides from Submerged Culture of Antrodia Camphorata S-29

Antrodia camphorata is a unique mushroom of Taiwan, which has been used as a natural therapeutic ingredient in Traditional Chinese Medicine (TCM) for protection of diverse health related conditions. Polysaccharides produced from A. camphorata have attracted much attention of research due to cytotoxic activity and miscellaneous activities. In this paper, we report on the fermentation conditions species-specific exopolysaccharides (EPS) from A. camphorata in submerged culture. A favorable medium for EPS production was obtained only by single-factor experiment, where Glucose and Yeast-Extracts were identified to be the most suitable carbon and nitrogen sources, with the concentration of 40 g/L and 5.0 g/L respectively. Zinc sulphate was identified to be the best salt source with the concentration of 0.4g/l. Initial pH and inoculum size for mycelial growth and EPS yield were 6.0 and 15% respectively. The maximum EPS production was 0.474 g/L in shake-flask culture, which is higher than the baseline media that was 0.351 g/L. This study provides the baseline information about production conditions for this specific specie which is crucial data to know before any further studies as it determines the properties and quantity of the desired produced specie. Keywords: A. camphorata; Exopolysaccharide; Sub­merged culture

Advances in the Study of Lactic Acid Bacteria as Vehicles for the In Vivo Delivery of Bioactive Substances

As a phenotypically and phylogenetically diverse group, lactic acid bacteria are found in a variety of natural environments and play an important role in medicine, bioengineering, food fermentation and agriculture. Lactic acid bacteria have a long history of use in food and have been considered as suitable vehicles for the production and targeted delivery of health-promoting or therapeutic bioactive substances due to their safety and probiotic properties, and the operability of their genetic systems. This article summarizes the latest studies on lactic acid bacteria as delivery vehicles in vivo with a focus on gene expression systems of lactic acid bacteria, the expression forms of bioactive substances and the application of lactic acid bacteria as delivery vehicles in the treatment of various diseases. It is hoped that this review will provide a basis for subsequent research

Metabolic fate of environmental chemical triclocarban in colon tissues: roles of gut microbiota involved.

Metabolic transformations play critical roles in the bioavailability and toxicities of environmental pollutants and toxicants. However, most previous research has focused on the metabolic reactions in host tissues, the gut microbiota-mediated biotransformation of environmental compounds is understudied. Using triclocarban (TCC) as a model environmental compound, here we study the metabolic fate of TCC in gut tissues and determine the roles of gut microbiota involved. We find that compared with other tissues, the colon tissue has a unique metabolic profile of TCC, with high abundance of the parent compound TCC and its free-form metabolites. Using a variety of approaches including antibiotic-mediated suppression of gut bacteria in vivo, germ-free mice, and in vitro culture of fecal bacteria, we found that the unique metabolic profile of TCC in the colon is mediated by the actions of gut microbiota. Overall, our findings support that gut microbiota plays important roles in colonic metabolism of TCC, highlighting the importance to consider the contributions of gut microbiota in toxicology evaluation of environmental compounds

A Surface Protein From Lactobacillus plantarum Increases the Adhesion of Lactobacillus Strains to Human Epithelial Cells

Adhesion to epithelial cells is considered important for Lactobacillus to exert probiotic effects. In this study, we found that trypsin treatment decreased the adhesion ability of Lactobacillus plantarum AR326 and AR269, which exhibit good adhesion ability, and surface proteins extracts increased the adhesion of the strains with poor adhesion ability. By SDS–polyacrylamide gel electrophoresis and mass spectrometry analysis, the main component of the surface proteins was detected and identified as a protein of approximately 37 kDa. It was 100% homologous with glyceraldehyde-3-phosphate dehydrogenase (GAPDH) from L. plantarum WCFS1. The adhesion of AR326 and AR269 was decreased significantly by blocking with the anti-GAPDH antibody, and GAPDH restored the adhesion of AR326 and AR269 treated with trypsin. In addition, purified GAPDH significantly increased the adhesion of the strains with poor adhesion ability. These results indicated that GAPDH mediates the adhesion of these highly adhesive lactobacilli to epithelial cells and can be used to improve the adhesion ability of probiotics or other bacteria of interest

Lactic Acid Bacteria With Antioxidant Activities Alleviating Oxidized Oil Induced Hepatic Injury in Mice

In order to screening new Lactic acid bacteria (LAB) strains to alleviating liver injury induced by oxidized oil, we isolated and screened LAB from Chinese fermented foods. Lactobacillus plantarum AR113, Pediococcus pentosaceus AR243, and Lactobacillus plantarum AR501 showed higher scavenging activity of α, α-Diphenyl-β-Picrylhydrazyl (DPPH) free radical and hydrogen radical, stronger inhibition of lipid peroxidation, and better protective effect on yeast cells in vitro. In vivo, oral administration of L. plantarum AR501 improved the antioxidant status of injury mice induced by oxidized oil including decreasing lipid peroxidation, recovering activities of antioxidant enzymes. Meanwhile, the gene expression of Nuclear factor erythroid 2-related factor 2 (Nrf2) of L. plantarum AR501 group was markedly elevated, and several antioxidant genes such as glutathione S-transferase (GSTO1), heme oxygenase-1 (HO-1), Glutamate cysteine ligase (GCL), and NAD(P)H:quinone oxidoreductase-l (NQO1) were subsequently up regulated in mice liver. Therefore, L. plantarum AR501 could be considered as potential candidates for production of functional foods that can alleviate the oxidative damage induced by oxidized oil

Purification and Partial Characterization of Bacteriocin Lac-B23, a Novel Bacteriocin Production by Lactobacillus plantarum J23, Isolated From Chinese Traditional Fermented Milk

The exploration and evaluation of bacteriocin-producing lactic acid bacteria (LAB) have been one of the powerful means to food preservation. A total of 300 strains were isolated from Chinese traditional fermented milk products. A bacteriocin-producing LAB, named Lactobacillus plantarum J23, was screened and identified. Bacteriocin Lac-B23 from L. plantarum J23 was purified by 80% ammonium sulfate precipitation, cation-exchange chromatography, and reverse-phase high-performance liquid chromatography. Molecular weight of bacteriocin Lac-B23 was determined to be approximately 6.73 kDa by tricine sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis, and it was confirmed as a novel bacteriocin by liquid chromatography-mass spectrometry. Moreover, bacteriocin Lac-B23 showed thermal stability when heated at below 100°C for 30 min, pH stability between pH 2.0 and 12.0, and sensitivity to trypsin, proteinase K, and proteinase E. The antimicrobial activity of bacteriocin could be enhanced by addition of Fe2+, Mn2+, and ethyl alcohol, and inhibited by Cu2+, K+, Ca2+, Zn2+, Mg2+, and sodium chloride. The results suggested bacteriocin Lac-B23 to have potential application prospects in the food industry

Development and Validation of a Targeted Screening Method for Anti-inflammatory Probiotics Based on a Dual-Luciferase Reporter System

A dual-luciferase reporter gene system to rapidly screen for probiotics with anti-inflammatory activity was constructed in this study. The conditions for the transfection of dual-luciferase plasmids containing nuclear factor-kappa B (NF-κB) response elements into 293T cells and the concentration of lipopolysaccharide (LPS) as an inducer were optimized. The anti-inflammatory activity of 86 selected strains was comparatively evaluated using this system and macrophage RAW264.7 cells. The results showed that the optimal transfection conditions were determined as 50:1, 1:1, 24 h and 100 ng/mL for pNF-κB-luc to pRL-TK plasmid ratio, plasmid to transfection reagent concentration ratio, transfection time, and LPS concentration, respectively. The dual-luciferase reporter system was reliable (Z’= 0.663 2) and stable (R2 = 0.746 99), and its results were consisted with those obtained using macrophage RAW264.7 cells. Finally, three strains with excellent anti-inflammatory effect, Lactiplantibacillus plantarum X30, Limosilactobacillus fermentum X58 and Weissella confusa X83, were obtained by this method. Each strain effectively inhibited the activation of the NF-κB pathway, significantly reduced the expression of pro-inflammatory factors such as interleukin (IL)-1β, tumor necrosis factor-α, and NF-κB p65, and increased the expression of IL-10. This system provides a new idea for targeted screening for probiotics with anti-inflammatory activity

Research Advances in Breeding and Tolerance of High Erythritol-Producing Strains

Erythritol is a natural four-carbon sugar alcohol with extensive application value in fields such as foods, pharmaceuticals, and chemical engineering. Currently, its industrial production primarily relies on microbial fermentation using renewable carbon sources as substrates. Yarrowia lipolytica is primarily used as starter culture for the production of erythritol. However, existing erythritol-producing strains commonly suffer from insufficient yield, poor environmental tolerance, and high production costs, which severely constrain the expansion of the scale of the erythritol industry. On this basis, this article focuses on three aspects: breeding strategies for erythritol-producing strains, novel tools and systems biology strategies, and enhancing strain tolerance to environmental stress, aiming to provide a theoretical foundation and technical references for the rational design of high erythritol-producing strains for the industrial production of erythritol

Preventive Effect of Lactobacillus paracasei FZU103 on Alcoholic Liver Injury in Mice

Objective: To explore the preventive effect of Lactobacillus paracasei FZU103 (LP-FZU103) on alcoholic liver injury (ALI). Methods: Altogether 36 specific pathogen free- (SPF-) grade ICR mice were randomly divided into three groups: control, model and experimental (LP-FZU103 intervention). After the six-week experiment, body mass, organ coefficients, serum and liver biochemical indexes, liver histopathology and inflammatory cytokines, the transcription of liver function-related genes and intestinal flora composition were measured. Results: Compared with the model group, intervention of LP-FZU103 improved the organ coefficients and pathological liver damage in ALI mice, significantly reduced the levels of total cholesterol (TC), triglyceride (TG) and low-density lipoprotein cholesterol (LDL-C) as well as the activity of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in the serum, increased the serum concentration of high-density lipoprotein cholesterol (HDL-C), significantly increased the activity of catalase (CAT) and superoxide dismutase (SOD) and the content of glutathione (GSH) in the liver, and decreased MDA content and interleukin-6 (IL-6), interferon-γ (IFN-γ) levels in the liver. Moreover, LP-FZU103 intervention significantly up-regulated the mRNA expression level of the lipid metabolism-related gene Ldlr and down-regulated the mRNA expression level of Acc1, Hmgcr and Cd36 as well as increased the relative abundance of beneficial bacteria such as Lactobacillus johnsonii, Lactobacillus reuteri and Lactobacillus paracasei in the gut of mice. Conclusion: LP-FZU103 intervention can prevent and control the occurrence of alcoholic liver injury in mice, which is closely related to the improved intestinal flora and liver metabolic function