Abstract：
The fecal microbiota of two healthy adults was cultivated in a medium containing commercial fructooligosaccharides [FOS; 1-kestose (GF2), nystose (GF3), and 1F-fructofuranosylnystose (GF4)]. Initially, the proportions of lactobacilli in the two feces samples were only 0.42% and 0.17%; however, they significantly increased to 7.2% and 4.8%, respectively, after cultivation on FOS. Most FOS-utilizing isolates could utilize only GF2; however, Lacticaseibacillus paracasei strain Lp02 could fully consume GF3 and GF4 too. The FOS operon (fosRABCDXE) was present in Lc. paracasei Lp02 and another Lc. paracasei strain, KCTC 3510T, but fosE was only partially present in the non-FOS-degrading strain KCTC 3510T. In addition, the top six upregulated genes in the presence of FOS were fosABCDXE, particularly fosE. FosE is a β-fructosidase that hydrolyzes both sucrose and all three FOS. Finally, a genome-based analysis suggested that fosE is mainly observed in Lc. paracasei, and only 13.5% (61/452) of their reported genomes were confirmed to include it. In conclusion, FosE allows the utilization of FOS, including GF3 and GF4 as well as GF2, by some Lc. paracasei strains, suggesting that this species plays a pivotal role in FOS utilization in the human gut.
摘要：
在含有商业低聚果糖[FOS;1-kestose（GF2），牡蛎（GF3），和1F-呋喃果糖糖(GF4)]。最初，两个粪便样本中乳杆菌的比例仅为0.42%和0.17%；然而，他们大幅增加到7.2%和4.8%，分别,在FOS上培养后。大多数利用FOS的分离株只能利用GF2；然而，副干酪乳杆菌菌株Lp02也可以完全消耗GF3和GF4。FOS操纵子(fosRABCDXE)存在于Lc中。paracaseiLp02和另一个Lc。副干酪菌株，KCTC3510T,但是fosE仅部分存在于非FOS降解菌株KCTC3510T中。此外,在存在FOS的情况下，前六个上调的基因是fosABCDXE，尤其是fose。FosE是水解蔗糖和所有三种FOS的β-果糖苷酶。最后,基于基因组的分析表明fosE主要在Lc中观察到。paracasei,只有13.5％（61/452）的报告基因组被确认包括它。总之,FosE允许使用FOS，包括GF3和GF4以及GF2，由一些Lc。副干酪菌株，这表明该物种在人类肠道中的FOS利用中起着关键作用。
