Glycogen and maltose utilization by Escherichia coli O157:H7 in the mouse intestine
Glycogen and maltose utilization by Escherichia coli O157:H7 in the mouse intestine
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DOI：
10.1128/iai.00096-08
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发表时间：
2008-06-01
影响因子：
3.1
通讯作者：
Conway, Tyrrell
中科院分区：
文献类型：
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作者：
Jones, Shari A.;Jorgensen, Mathias;Conway, Tyrrell
突变筛选和转录组研究使我们考虑葡萄糖聚合物的代谢，即麦芽糖、麦芽糖糊精和糖原，对大肠杆菌在肠道的定植是否重要。通过使用链霉素处理的小鼠模型，我们发现双糖麦芽糖的分解代谢在体内对致病性大肠杆菌O157:H7和共生大肠杆菌K-12具有竞争优势，而外源形式的更复杂的葡萄糖聚合物麦芽糖糊精的降解则没有竞争优势。内源性葡萄糖聚合物，糖原，似乎在定植中起重要作用，因为不能合成或降解糖原的突变体具有明显的定植缺陷。为了支持大肠杆菌在饥荒期间依靠内部碳储存来维持定植的假设，我们发现，通过在动物的饮用水中提供持续供应的易代谢糖，即葡萄糖酸盐，大肠杆菌糖原代谢突变体的竞争劣势得以挽救。结果表明，糖原储存可能在肠道细菌中广泛存在，因为它是维持肠道快速生长所必需的，肠道中存在激烈的资源竞争和偶尔的饥荒。这项研究的一个重要意义是，大肠杆菌使用的糖在肠道中数量有限，这使得内源性碳储存有价值。因此，通过使用益生菌或益生元来控制肠道微生物群，从而限制大肠杆菌O157:H7和其他病原体喜欢的糖的可用性，可能是有价值的。
Mutant screens and transcriptome studies led us to consider whether the metabolism of glucose polymers, i.e., maltose, maltodextrin, and glycogen, is important for Escherichia coli colonization of the intestine. By using the streptomycin-treated mouse model, we found that catabolism of the disaccharide maltose provides a competitive advantage in vivo to pathogenic E. coli O157:H7 and commensal E. coli K-12, whereas degradation of exogenous forms of the more complex glucose polymer, maltodextrin, does not. The endogenous glucose polymer, glycogen, appears to play an important role in colonization, since mutants that are unable to synthesize or degrade glycogen have significant colonization defects. In support of the hypothesis that E. coli relies on internal carbon stores to maintain colonization during periods of famine, we found that by providing a constant supply of a readily metabolized sugar, i.e., gluconate, in the animal's drinking water, the competitive disadvantage of E. coli glycogen metabolism mutants is rescued. The results suggest that glycogen storage may be widespread in enteric bacteria because it is necessary for maintaining rapid growth in the intestine, where there is intense competition for resources and occasional famine. An important implication of this study is that the sugars used by E. coli are present in limited quantities in the intestine, making endogenous carbon stores valuable. Thus, there may be merit to combating enteric infections by using probiotics or prebiotics to manipulate the intestinal microbiota in such a way as to limit the availability of sugars preferred by E. coli O157:H7 and perhaps other pathogens.