Department of Chemical and Bioprocess Engineering, School of Engineering, Pontificia Universidad Catolica de Chile, Chile.
Department of Nutrition, School of Medicine, Universidad de Chile, Chile.
Food Res Int. 2018 Jul;109:14-23. doi: 10.1016/j.foodres.2018.04.008. Epub 2018 Apr 11.
The gut microbiome has a significant impact on host health, especially at the metabolic level. Dietary compounds arriving at the colon have a large influence on the composition of the gut microbiome. High fiber diets have been associated to health benefits that are mediated in great part by short chain fatty acids (SCFA). Gut microbial interactions are relevant for the utilization of complex carbohydrates in the gut microbiome. In this work we characterized the utilization of two dietary polysaccharides by combinations of representative adult gut microbes, and the impact of their activities on a cellular inflammation model. Paired combinations of Bifidobacterium adolescentis, Bacteroides dorei, Lactobacillus plantarum, Escherichia coli and Clostridium symbiosum were grown in inulin or xylan as carbon source. Their relative abundance, substrate consumption and major SCFAs produced were determined. Higher cell growth was observed during inulin consumption, and B. adolescentis and L. plantarum were dominant in co-cultures. The co-culture of B. dorei and C. symbiosum was dominant in xylan. In several cases the combined bacterial growth was lower in co-cultures than monocultures, with a few exceptions of synergistic growth between microorganisms. Inulin fermentation resulted in larger acetate and lactate concentrations, and several combinations grown in xylan containing C. symbiosum were characterized by high amounts of butyrate. These microbial consortia were scaled to batch bioreactor fermentations reaching high cell densities and similar profiles to co-culture experiments. Interestingly, a microbial combination producing high amounts of butyrate was able to reduce IL-8 expression in HT-29 cells co-incubated with TNFα. In summary, this work shows that microbial interactions during the utilization of dietary polysaccharides are complex and substrate dependent. Moreover, certain combinations deploy potent anti-inflammatory effects, which are independent of individual microbial growth, and could be mediated in part by higher butyrate production.
肠道微生物组对宿主健康有重大影响，尤其在代谢水平上。到达结肠的膳食化合物对肠道微生物组的组成有很大影响。高纤维饮食与健康益处有关，这些益处在很大程度上是由短链脂肪酸（SCFA）介导的。肠道微生物相互作用与肠道微生物组中复杂碳水化合物的利用有关。在这项工作中，我们描述了两种膳食多糖在代表性成人肠道微生物组合中的利用情况，以及它们的活性对细胞炎症模型的影响。将双歧杆菌、多形拟杆菌、植物乳杆菌、大肠杆菌和共生梭菌的成对组合作为碳源在菊粉或木聚糖中生长。确定了它们的相对丰度、底物消耗和主要产生的 SCFA。在菊粉消耗过程中观察到更高的细胞生长，并且在共培养物中双歧杆菌和植物乳杆菌占优势。多形拟杆菌和共生梭菌的共培养物在木聚糖中占优势。在几种情况下，与单培养物相比，共培养物中的细菌生长较低，但微生物之间存在一些协同生长的例外。菊粉发酵导致乙酸盐和乳酸盐浓度增加，并且在含有共生梭菌的几种木聚糖生长的组合中，丁酸盐含量很高。这些微生物群落被放大到分批生物反应器发酵中，达到了高细胞密度和与共培养实验相似的图谱。有趣的是，能够产生大量丁酸盐的微生物组合能够降低与 TNFα 共孵育的 HT-29 细胞中 IL-8 的表达。总之，这项工作表明，在利用膳食多糖过程中微生物的相互作用是复杂的，并且依赖于底物。此外，某些组合具有很强的抗炎作用，这种作用与单个微生物的生长无关，部分可能是通过更高的丁酸盐产生来介导的。
