MOLECULAR INTERACTION BETWEEN BIFIDOBACTERIUM AND ESCHERICHIA VIA CARBOHYDRATES.

A few hunderd trillion bacteria cells live with human. Most of such bacteria live in human gut. Among human gut bacteria, 2 members of the phyla Firmicutes and Bacteroidetes occupy the majority. It is known that bacterial interactions among Firmicutes and Bacteroidetes in a gut strongly contribute indivisual human health. In this study, I showed the novel molecular interaction between Escherichia and Bifidobacterium, minority bacteria in huma gut. First, I identified the transporter genes of E. coli induced by the conditioned medium of B. longum. Northern blotting and luciferase repoter assays indicated that the uhpT and idnT promoters were significantly induced by the conditioned medium of B. longum but not by the conditioned medium of E. coli. The induction of the uhpT promoter was also found by the culture supernatant of the other species of Bifidobacterium. The recombinant glucose-6-phosphate dehydrogenase of Leuconostoc mesenteroides was over expressed in E. coli and purified by affinity chromatography. The purified glucose-6-phosphate dehydrogenase suppress the induction of the uhpT promoter by the conditioned medium of B. longum. These results suggest that the carbonhydrates secreted from Bifidobacterium species support the glucose-6-phosphate utilization of E. coli