基于“微生物-肠-脑”轴的肠道菌群参与抑郁症相关研究进展

抑郁症是现代社会较为普遍的精神障碍类疾病之一。抑郁症不仅严重危害人们的生活质量，还因为其高自杀率及致残率给家庭和社会带来巨大负担。近年来国内外的研究表明，肠道菌群在抑郁症的发生和发展中扮演着重要角色，肠-脑通信功能紊乱可能是抑郁症的重要病理机制，“微生物-肠-脑”轴是肠道菌群参与的肠道和大脑双向信息交流的通道。目前相关研究主要集中在抑郁症个体菌群特征和肠道菌群与抑郁症发病关系的探索方面，提示维护健康的肠道菌群可能是抑郁症预防和治疗的新思路。本文对相关方面的研究进展进行总结，以期从“微生物-肠-脑”轴角度为抗抑郁活性物质作用机理研究提供深入解释，也为益生菌在新的抑郁症治疗手段方面的应用提供参考与借鉴。     

益生菌对生物体内持久性有机污染物和重金属的调节作用研究进展

持久性有机污染物和重金属的污染问题是全球关注的重要问题，其持续暴露会带来严重的生态风险和健康问题。这些污染物具有稳定的物理和化学性质，在生物体和环境中存在持久性、生物累积性、毒性以及较强的长距离迁移的能力而受到广泛关注。研究表明，持久性有机污染物和重金属在生物体内的积累会引起生物体的氧化应激和免疫损伤，破坏肠道微生物群的组成结构，打破肠道菌群的平衡。益生菌能够维持宿主肠道微生物群的平衡与稳定，有效提高生物体的抗氧化能力和免疫细胞的活性。益生菌已被证明能够减少宿主体内污染物的积累、提高宿主的免疫功能和调节肠道菌群的平衡，从而降低污染物引起的毒性作用。因此，本文综述了益生菌对生物体内持久性污染物和重金属毒性的调节作用，旨在为污染物的消减提供理论参考。     

Fermented coconut jelly as a probiotic vehicle,physicochemical and microbiology characterisation during an in vitro digestion

There is little information on the survival of probiotics in plant-based foods after simulated gastric and intestinal conditions, likewise the microstructure arrangement in the no-dairy fermented food. This work aimed to study if the agar–agar in a fermented coconut jelly confers protection to probiotics, phenolic and antioxidant compounds during in vitro digestion. Samples containing higher agar–agar amounts tend to retain (P < 0.05) antioxidant and phenolic compounds in their network better, even after the in vitro digestion. Also, a compact and homogeneous microstructure was observed by the Confocal Laser Scanning Microscopy. The texture profile analysis shows that 1% of agar samples presented the maximum hardness (P < 0.05) due to more bonding points and intermolecular interactions. Finally, the survival of probiotics remained above the recommended values (10⁶–10⁷ CFU g⁻¹) after the in vitro digestion of a product with probiotic potential.     

Effects of yogurt containing probiotics on respiratory virus infections: Influenza H1N1 and SARS-CoV-2

Respiratory virus infections are an escalating issue and have become common worldwide. Influenza and COVID-19 are typical infectious respiratory diseases, and they sometimes lead to various complications. In a situation in which no established drug or treatment exists, consumption of proper food might be beneficial in maintaining health against external infections. We studied the potential effects of mixtures of probiotic strains on various viral infections. The purpose of this study was to assess the ability of yogurt containing probiotics to reduce the risk of respiratory viruses such as influenza H1N1 and SARS-CoV-2 infection. First, we performed in vitro tests using infected Madin-Darby canine kidney (MDCK) and Vero E6 cells, to evaluate the potential effects of yogurt containing high-dose probiotics against influenza H1N1 and SARS-CoV-2 infection. The yogurt significantly reduced plaque formation in the virus-infected cells. We also performed in vivo tests using influenza H1N1-infected C57BL/6 mice and SARS-CoV-2-infected Syrian golden hamsters, to evaluate the potential effects of yogurt. Yogurt was administered orally once daily during the experimental period. Yogurt was also administered orally as pretreatment once daily for 3 wk before viral infection. Regarding influenza H1N1, it was found that yogurt caused an increase in the survival rate, body weight, and IFN-γ, IgG1, and IL-10 levels against viral infection and a decrease in the inflammatory cytokines TNF-α and IL-6. Although the SARS-CoV-2 copy number was not significantly reduced in the lungs of yogurt-treated SARS-CoV-2-infected hamsters, the body weights and histopathological findings of the lungs were improved in the yogurt-treated group. In conclusion, we suggest that consumption of yogurt containing probiotics can lead to beneficial effects to prevent respiratory viral infections.     

Gluco-oligosaccharides as potential prebiotics: Synthesis,purification, structural characterization,and evaluation of prebiotic effect

Prebiotics have long been used to modulate the gut microbiota and improve host health. Most established prebiotics are nondigestible carbohydrates, especially short-chain oligosaccharides. Recently, gluco-oligosaccharides (GlcOS) with 2–10 glucose residues and one or more O-glycosidic linkage(s) have been found to exert prebiotic potentials (not fully established prebiotics) because of their selective fermentation by beneficial gut bacteria. However, the prebiotic effects (non-digestibility, selective fermentability, and potential health effects) of GlcOS are highly variable due to their complex structure originating from different synthesis processes. The relationship between GlcOS structure and their potential prebiotic effects has not been fully understood. To date, a comprehensive summary of the knowledge of GlcOS is still missing. Therefore, this review provides an overview of GlcOS as potential prebiotics, covering their synthesis, purification, structural characterization, and prebiotic effect evaluation. First, GlcOS with different structures are introduced. Then, the enzymatic and chemical processes for GlcOS synthesis are critically reviewed, including reaction mechanisms, substrates, catalysts, the structures of resultant GlcOS, and the synthetic performance (yield and selectivity). Industrial separation techniques for GlcOS purification and structural characterization methods are discussed in detail. Finally, in vitro and in vivo studies to evaluate the non-digestibility, selective fermentability, and associated health effects of different GlcOS are extensively reviewed with a special focus on the GlcOS structure–function relationship.     

肠源性三甲胺生成机制及其饮食调控

食物中含有的胆碱、左旋肉碱、甜菜碱等物质在肠道菌群的作用下可转化为三甲胺(trimethylamine, TMA)。TMA极易被肠道上皮细胞吸收,通过门静脉循环被转运至肝脏后氧化为氧化三甲胺(trimethylamine-N-oxide, TMAO),血浆中TMAO的水平与人体心血管疾病的发生发展密切相关。因此,肠源性TMA被认为是一种心血管疾病的风险标志。TMA作为肠道菌群的一种代谢产物,将饮食、肠道菌群、心血管疾病三者有机地联系到了一起,为通过饮食和肠道菌群预防和治疗心血管疾病,提供了新的靶点；心血管疾病严重危害人类健康,通过对肠源性TMA生成机制及其饮食调控的分析,可为控制肠源性TMA、降低心血管疾病发生提供参考。阐述了肠源性TMA前体物质的食物来源、参与TMA生成的肠道微生物,系统阐释了TMA在人体内的代谢途径。针对肠源性TMA的控制,从减少食物中TMA前体物质摄入、降低产生TMA肠道菌群的比例、抑制产生TMA的酶类以及干预TMA分子合成途径等方面分别总结了肠源性TMA的控制策略。针对具有良好应用前景的益生菌和古菌干预策略,归纳和分析了目前益生菌和古菌对TMA影响的研究成果,为预防心血管疾病提供可能的方向。     

益生菌发酵乳辅助调节机体健康的研究进展

益生菌发酵乳是益生菌的重要载体，可通过改善宿主肠道微生物菌群的平衡，促进有益成分代谢增强发酵乳的营养健康属性。文章阐述了益生菌发酵乳在改善肠道功能、调节机体免疫、辅助治疗代谢性疾病、改善神经系统疾病等方面的辅助功效，并对益生菌发酵乳的发展方向进行了展望。