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Abstract：
Harnessing the microbiota for beneficial outcomes is limited by our poor understanding of the constituent bacteria, as the functions of most of their genes are unknown. Here, we measure the growth of a barcoded transposon mutant library of the gut commensal Bacteroides thetaiotaomicron on 48 carbon sources, in the presence of 56 stress-inducing compounds, and during mono-colonization of gnotobiotic mice. We identify 516 genes with a specific phenotype under only one or a few conditions, enabling informed predictions of gene function. For example, we identify a glycoside hydrolase important for growth on type I rhamnogalacturonan, a DUF4861 protein for glycosaminoglycan utilization, a 3-keto-glucoside hydrolase for disaccharide utilization, and a tripartite multidrug resistance system specifically for bile salt tolerance. Furthermore, we show that B. thetaiotaomicron uses alternative enzymes for synthesizing nitrogen-containing metabolic precursors based on ammonium availability and that these enzymes are used differentially in vivo in a diet-dependent manner.
摘要：
由于我们对组成细菌的理解不足，因此利用微生物区来获得有益的结果受到限制。因为他们大多数基因的功能都是未知的。这里,我们测量了48个碳源上的肠道共生拟杆菌的条形码转座子突变文库的生长，在56种应激诱导化合物的存在下，以及在侏儒小鼠的单一定殖过程中。我们仅在一种或几种条件下鉴定出516个具有特定表型的基因，能够对基因功能进行明智的预测。例如,我们确定了一种对I型鼠李糖半乳糖醛酸生长重要的糖苷水解酶，用于糖胺聚糖利用的DUF4861蛋白，一种用于二糖利用的3-酮-葡萄糖苷水解酶，以及专门针对胆盐耐受性的三方多药耐药系统。此外，我们表明，B.thetaiotaomicron使用替代酶来合成基于铵可用性的含氮代谢前体，并且这些酶以饮食依赖性方式在体内差异使用。
