运动介导肠道微生物-肠-脑轴调控神经功能的机制

神经功能障碍是导致脑认知能力衰退和神经退行性疾病的重要原因,但其内在的诱导机制尚不清楚。随着学界对肠道微生物研究的深入,发现肠道微生物在许多机体疾病的发展中扮演重要角色,而神经功能障碍亦不例外。肠神经系统与中枢神经系统的信息通路使得肠道微生物与神经功能建立了肠-脑轴间的联络,肠道微生态的变化可通过肠-脑轴间的联络而影响神经功能。研究发现,规律的运动可通过影响肠道微生态进而改善神经功能,抑制神经系统疾病,但其内在调节机制亦不明确,这可能与运动介导肠道微生物多样性、肠道免疫、肠道内分泌、肠道代谢以及运动改善肠-脑间神经联系和神经发生等机制有关。     

Gut microbiota and obesity:Impact of antibiotics and prebiotics and potential for musculoskeletal health

Obesity is a complex disease with multiple contributing factors.One of the most intensely studied factors during the past decade has been the gut microbiota,which is the community of all microbes in the intestinal tract.The gut microbiota,via energy extraction,inflammation,and other actions,is now recognized as an important player in the pathogenesis of obesity.Dysbiosis,or an imbalance in the microbial community,can initiate a cascade of metabolic disturbances in the host.Early life is a particularly important period for the development of the gut microbiota,and perturbations such as with antibiotic exposure can have long-lasting consequences for host health.In early life and throughout the life span,diet is one of the most important factors that shape the gut microbiota.Although diets high in fat and sugar have been shown to contribute to dysbiosis and disease,dietary fiber is recognized as an important fermentative fuel for the gut microbiota and results in the production of short-chain fatty acids that can act as signaling molecules in the host.One particular type of fiber,prebiotic fiber,contributes to changes in the gut microbiota,the most notable of which is an increase in the abundance of Bifidobacterium.This review highlights our current understanding of the role of gut microbiota in obesity development and the ways in which manipulating the microbiota through dietary means,specifically prebiotics,could contribute to improved health in the host,including musculo skeletal health.     

半乳甘露寡糖对断奶仔猪肠道微生物多样性的影响

采用PCR-DGGE方法,研究添加0.25%林肯霉素及0.1%、0.2%和0.3%的半乳甘露寡糖(GMOS)对断奶仔猪肠道微生物多样性的影响.结果表明,结肠微生物DNA电泳条带的数量明显多于回肠中的数量;断奶后0 d的回肠条带数量多于断奶后14 d的数量,但两者间结肠微生物种类差异不大.唾液乳酸杆菌、瘤胃球菌和大肠杆菌为仔猪回肠共有菌;而金色葡萄球菌、唾液乳酸杆菌、瘤胃球菌、枯草芽孢杆菌和产气荚膜梭状芽孢杆菌是结肠的共有菌.由相似性分析可见,各日粮处理间电泳带谱之间相似性较低,除了对照组和0.2%GMOS组断奶仔猪回肠微生物各带谱间存在80%的相似性外,其他各组的回肠微生物各谱带间的相似性大部分在20%~50%之间.这表明饲喂不同日粮的断奶仔猪,其肠道相同微生物种群数量相同者较少,各自特有的微生物种群数量较多.     

Metagenomics approach to identify lignocellulose-degrading enzymes in the gut microbiota of the Chinese bamboo rat cecum

BackgroundLignocellulose is considered a renewable organic material, but the industrial production of biofuel from lignocellulose is challenging because of the lack of highly active hydrolytic enzymes. The guts of herbivores contain many symbiotic microorganisms that have evolved to hydrolyze plant lignocellulose. Chinese bamboo rats mainly consume high-fiber foods, indicating that some members of the intestinal tract microbiota digest lignocellulose, providing these rats with the energy required for growth.ResultsHere, we used metagenomics to analyze the diversity and functions of the gut microbiota in Chinese bamboo rats. We identified abundant populations of lignocellulose-degrading bacteria, whose main functions involved carbohydrate, amino acid, and nucleic acid metabolism. We also found 587 carbohydrate-active enzyme genes belonging to different families, including 7 carbohydrate esterase families and 21 glycoside hydrolase families. The glycoside hydrolase 3, glycoside hydrolase 1, glycoside hydrolase 43, carbohydrate esterase 4, carbohydrate esterase 1, and carbohydrate esterase 3 families demonstrated outstanding performance.ConclusionsThe microbes and enzymes identified in our study expand the existing arsenal of proficient degraders and enzymes for lignocellulosic biofuel production. This study also describes a powerful approach for targeting gut microbes and enzymes in numerous industries.How to cite: Bai D, Lin X, Hu Y, et al. Metagenomics approach to identify lignocellulose-degrading enzymes in the gut microbiota of the Chinese bamboo rat cecum. Electron J Biotechnol 2021;50. https://doi.org/10.1016/j.ejbt.2020.12.001     

High-throughput sequencing identifies salivary microbiota in Chinese caries-free preschool children with primary dentition

Objectives: The study aimed at identifying salivary microbiota in caries-free Chinese preschool children using highthroughput sequencing. Methods: Saliva samples were obtained from 35 caries-free preschool children(18 boys and 17 girls)with primary dentition, and 16 S ribosomal DNA(r DNA) V3–V4 hypervariable regions of the microorganisms were analyzed using Illumina MiSeq. Results: At 97% similarity level, all of these reads were clustered into 334 operational taxonomic units(OTUs). Among these, five phyla(Firmicutes, Proteobacteria, Actinobacteria, Bacteroidetes, and Candidate division TM7) and13 genera(Streptococcus, Rothia, Granulicatella, Prevotella, Enterobacter, Veillonella, Neisseria, Staphylococcus, Janthinobacterium, Pseudomonas, Brevundimonas, Devosia, and Gemella) were the most dominant, constituting 99.4% and 89.9% of the salivary microbiota, respectively. The core salivary microbiome comprised nine genera(Actinomyces, Capnocytophaga, Gemella,Granulicatella, Lachnoanaerobaculum, Neisseria, Porphyromonas, Rothia, and Streptococcus). Analysis of microbial diversity and community structure revealed a similar pattern between male and female subjects. The difference in microbial community composition between them was mainly attributed to Neisseria(P=0.023). Furthermore, functional prediction revealed that the most abundant genes were related to amino acid transport and metabolism. Conclusions: Our results revealed the diversity and composition of salivary microbiota in caries-free preschool children, with little difference between male and female subjects.Identity of the core microbiome, coupled with prediction of gene function, deepens our understanding of oral microbiota in cariesfree populations and provides basic information for associating salivary microecology and oral health.     

半乳甘露寡糖对断奶仔猪肠道微生物多样性的影响

采用PCR-DGGE方法,研究添加0.25%林肯霉素及0.1%、0.2%和0.3%的半乳甘露寡糖(GMOS)对断奶仔猪肠道微生物多样性的影响.结果表明,结肠微生物DNA电泳条带的数量明显多于回肠中的数量;断奶后0 d的回肠条带数量多于断奶后14 d的数量,但两者间结肠微生物种类差异不大.唾液乳酸杆菌、瘤胃球菌和大肠杆菌为仔猪回肠共有菌;而金色葡萄球菌、唾液乳酸杆菌、瘤胃球菌、枯草芽孢杆菌和产气荚膜梭状芽孢杆菌是结肠的共有菌.由相似性分析可见,各日粮处理间电泳带谱之间相似性较低,除了对照组和0.2%GMOS组断奶仔猪回肠微生物各带谱间存在80%的相似性外,其他各组的回肠微生物各谱带间的相似性大部分在20%~50%之间.这表明饲喂不同日粮的断奶仔猪,其肠道相同微生物种群数量相同者较少,各自特有的微生物种群数量较多.     

污泥复混肥对土壤微生物区系影响的研究

对旱地和水田的施用试验结果表明,施用污泥复混肥与等量化肥相比,在本试验的施肥水平下,对硝化细菌和好气性纤维素分解细菌的繁衍具有明显的促进作用,对好气细菌,真菌,放线菌和氨化细菌不但没有不良影响,反而稍有促进作用,而且随污泥复混肥中污泥含量的提高而增强。     

运动干预调控肠道微生物介导认知功能的作用研究进展

认知功能障碍是神经系统疾病的重要特征表现,受诸多因素影响。肠道微生物在维持机体健康和多种疾病的发展中发挥作用,肠道微生物失衡与躯体运动能力和脑认知功能障碍,如阿尔茨海默病和帕金森病等神经退行性疾病关系密切。研究发现,运动干预可通过对肠道微生物的调节,建立肠-脑之间的联系,调控认知功能,改善神经退行性疾病,但不同方式的运动干预对肠道微生物的影响及其与认知功能的调节之间存在差异性。通过分析肠道微生物的生物学功能以及运动介导肠道微生物相关的改变与脑认知功能的关系,探讨肠道微生物在肠-脑神经联络以及运动调控肠道微生物改善认知功能的作用机理。     

昆虫共生菌及其在病虫害防控中的应用前景

昆虫的种类丰富多样,其体内栖息着大量的微生物。这些微生物与宿主昆虫在长期协同进化过程中形成了相互依存的共生关系。共生菌在昆虫的营养、代谢、免疫和生殖等诸多生理功能上发挥着重要作用,因此,昆虫共生菌是昆虫个体的重要组成部分,全面了解昆虫生命活动必须兼顾昆虫共生菌的作用和影响。同时,昆虫共生菌在开发害虫新型生物防治、废弃物生物降解和虫媒传染病的阻断控制手段中具有重要的应用前景。文章综述了昆虫共生菌的多样性、生物学功能、与宿主相互作用的机制及其在病虫害和虫媒传染病防治上的应用,并对未来研究提出展望。     

Vibrio sp. ArtGut-C1, a polyhydroxybutyrate producer isolated from the gut of the aquaculture live diet Artemia (Crustacea)

BackgroundVibrio species display variable and plastic fitness strategies to survive and interact with multiple hosts, including marine aquaculture species that are severely affected by pathogenic Vibrios. The culturable Vibrio sp. strain ArtGut-C1, the focus of this study, provides new evidence of such phenotypic plasticity as it accumulates polyhydroxybutyrate (PHB), a biodegradable polymer with anti-pathogen activity, particularly in the marine larviculture phase. The strain was isolated from the gut of laboratory-reared Artemia individuals, the live diet and PHB carrier used in larviculture. Its main phenotypic properties, taxonomic status and genomic properties are reported based on the whole-genome sequencing.ResultsVibrio sp. ArtGut-C1 yielded 72.6% PHB of cells’ dry weight at 25°C. The genomic average nucleotide identity (ANI) shows it is closely related to V. diabolicus (ANI: 88.6%). Its genome contains 5,236,997-bp with 44.8% GC content, 3,710 protein-coding sequences, 96 RNA, 9 PHB genes functionally related to PHB metabolic pathways, and several genes linked to competing and colonizing abilities.ConclusionsThis culturable PHB-accumulating Vibrio strain shows high genomic and phenotypic variability. It may be used as a natural pathogen biocontrol in the marine hatchery and as a potential cell factory for PHB production.How to cite: Yévenes M, Quiroz M, Maruyama F, et al. Vibrio sp. ArtGut-C1, a polyhydroxybutyrate producer isolated from the gut of the aquaculture live diet Artemia (Crustacea). Electron J Biotechnol 2021;49. https://doi.org/10.1016/j.ejbt.2020.10.003