Abstract：
As the most abundant gram-negative bacterial order in the gastrointestinal tract, Bacteroidales bacteria have been extensively studied for their contribution to various aspects of gut health. These bacteria are renowned for their involvement in immunomodulation and their remarkable capacity to break down complex carbohydrates and fibers. However, the human gut microbiota is known to produce many metabolites that ultimately mediate important microbe-host and microbe-microbe interactions. To gain further insights into the metabolites produced by the gut commensal strains of this order, we examined the metabolite composition of their bacterial cell cultures in the stationary phase. Based on their abundance in the gastrointestinal tract and their relevance in health and disease, we selected a total of six bacterial strains from the relevant genera Bacteroides, Phocaeicola, Parabacteroides, and Segatella. We grew these strains in modified Gifu anaerobic medium (mGAM) supplemented with mucin, which resembles the gut microbiota\'s natural environment. Liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based metabolite profiling revealed 179 annotated metabolites that had significantly differential abundances between the studied bacterial strains and the control growth medium. Most of them belonged to classes such as amino acids and derivatives, organic acids, and nucleot(s)ides. Of particular interest, Segatella copri DSM 18205 (previously referred to as Prevotella copri) produced substantial quantities of the bioactive metabolites phenylethylamine, tyramine, tryptamine, and ornithine. Parabacteroides merdae CL03T12C32 stood out due to its ability to produce cadaverine, histamine, acetylputrescine, and deoxycarnitine. In addition, we found that strains of the genera Bacteroides, Phocaeicola, and Parabacteroides accumulated considerable amounts of proline-hydroxyproline, a collagen-derived bioactive dipeptide. Collectively, these findings offer a more detailed comprehension of the metabolic potential of these Bacteroidales strains, contributing to a better understanding of their role within the human gut microbiome in health and disease.
摘要：
作为胃肠道中最丰富的革兰氏阴性菌，已广泛研究了拟杆菌细菌对肠道健康各个方面的贡献。这些细菌以其参与免疫调节和其显著的分解复杂碳水化合物和纤维的能力而闻名。然而,已知人类肠道微生物群产生许多代谢物，这些代谢物最终介导重要的微生物-宿主和微生物-微生物相互作用。为了进一步了解该顺序的肠道共生菌株产生的代谢物，我们检查了静止期细菌细胞培养物的代谢物组成。基于它们在胃肠道中的丰度及其与健康和疾病的相关性，我们从相关的拟杆菌属中选择了总共6个细菌菌株，Phocaeicola,副杆菌属,还有Segatella.我们在添加了粘蛋白的改良Gifu厌氧培养基（mGAM）中培养了这些菌株，这类似于肠道微生物群的自然环境。基于液相色谱-串联质谱（LC-MS/MS）的代谢物分析显示，179种注释的代谢物在研究的细菌菌株和对照生长培养基之间具有显着差异的丰度。它们中的大多数属于氨基酸和衍生物等类别，有机酸,和核仁。特别感兴趣的是，SegatellacopriDSM18205（以前称为Prevotellacopri）产生了大量的生物活性代谢物苯乙胺，酪胺,色胺,和鸟氨酸.副杆菌CL03T12C32因其产生尸胺的能力而脱颖而出，组胺,乙酰腐胺,和脱氧肉碱.此外,我们发现拟杆菌属的菌株，Phocaeicola,并积累了大量的脯氨酸-羟脯氨酸，胶原衍生的生物活性二肽。总的来说，这些发现提供了对这些拟杆菌菌株的代谢潜力的更详细的理解，有助于更好地了解它们在人类肠道微生物组在健康和疾病中的作用。
