Li Miaomiao, Li Guangsheng, Zhu Liying, Yin Yeshi, Zhao Xiaoliang, Xiang Charlie, Yu Guangli, Wang Xin
Shandong Provincial Key Laboratory of Glycoscience and Glycotechnology, and Key Laboratory of Marine Drugs of Ministry of Education, Ocean University of China, Qingdao, Shandong, China.
State Key Laboratory of Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou, Zhejiang, China; Key laboratory for Food Microbial Technology of Zhejiang Province, Zhejiang Academy of Agricultural Sciences, Hangzhou, Zhejiang, China.
PLoS One. 2014 Mar 12;9(3):e91106. doi: 10.1371/journal.pone.0091106. eCollection 2014.
Agarose (AP) from red algae has a long history as food ingredients in East Asia. Agaro-oligosaccharides (AO) derived from AP have shown potential prebiotic effects. However, the human gut microbes responsible for the degradation of AO and AP have not yet been fully investigated. Here, we reported that AO and AP can be degraded and utilized at various rates by fecal microbiota obtained from different individuals. Bacteroides uniformis L8 isolated from human feces showed a pronounced ability to degrade AO and generate D-galactose as its final end product. PCR-DGGE analysis showed B. uniformis to be common in the fecal samples, but only B. uniformis L8 had the ability to degrade AO. A synergistic strain, here classified as Escherichia coli B2, was also identified because it could utilize the D-galactose as the growth substrate. The cross-feeding interaction between B. uniformis L8 and E. coli B2 led to exhaustion of the AO supply. Bifidobacterium infantis and Bifidobacterium adolescentis can utilize one of the intermediates of AO hydrolysis, agarotriose. Growth curves indicated that AO was the substrate that most favorably sustained the growth of B. uniformis L8. In contrast, κ-carrageenan oligosaccharides (KCO), guluronic acid oligosaccharides (GO), and mannuronic acid oligosaccharides (MO) were found to be unusable to B. uniformis L8. Current results indicate that B. uniformis L8 is a special degrader of AO in the gut microbiota. Because B. uniformis can mitigate high-fat-diet-induced metabolic disorders, further study is required to determine the potential applications of AO.
红藻中的琼脂糖（AP）作为东亚地区的食品成分已有很长历史。从AP衍生而来的琼脂寡糖（AO）已显示出潜在的益生元效应。然而，负责降解AO和AP的人体肠道微生物尚未得到充分研究。在此，我们报告称，不同个体的粪便微生物群能够以不同速率降解和利用AO和AP。从人类粪便中分离出的单形拟杆菌L8显示出显著的降解AO并产生D-半乳糖作为最终终产物的能力。PCR-DGGE分析表明单形拟杆菌在粪便样本中很常见，但只有单形拟杆菌L8具有降解AO的能力。还鉴定出一种协同菌株，在此归类为大肠杆菌B2，因为它可以利用D-半乳糖作为生长底物。单形拟杆菌L8和大肠杆菌B2之间的交叉喂养相互作用导致AO供应耗尽。婴儿双歧杆菌和青春双歧杆菌可以利用AO水解的一种中间体琼脂三糖。生长曲线表明AO是最有利于单形拟杆菌L8生长的底物。相比之下，发现κ-卡拉胶寡糖（KCO）、古洛糖醛酸寡糖（GO）和甘露糖醛酸寡糖（MO）对单形拟杆菌L8不可用。目前的结果表明单形拟杆菌L8是肠道微生物群中AO的一种特殊降解菌。由于单形拟杆菌可以减轻高脂饮食诱导的代谢紊乱，因此需要进一步研究以确定AO的潜在应用。
