Figure 6

Co-colonization and colonization displacement studies demonstrating the role of glycogen biosynthesis on competitive gut retention. (A) Co-colonization of both the glycogen-deficient ?glgA mutant and the parent strain in germ-free 129S6/SvEv mice resulted in an overall 2 log reduction of the ?glgA mutant population. Data shown represent the median cell counts values and mean cell counts??standard deviation from all four mice. (B) Addition of the parent strain to gnotobiotic mice previously mono-colonized with the ?glgA mutant resulted in a population shift with gradual displacement of the mutant population by the parent. Red arrow indicates the timepoint at which the parent strain was administered in a single gavage dose of 5 x 10⁸CFU. Data shown represent the average cell counts values and mean cell counts??standard deviation from all three mice. An asterisk (*) indicates a statistically significant difference between the mutant and parent populations (p-value?<?0.05). Both in vivo studies established that a functional glycogen biosynthetic pathway contributes to the competitive advantage and retention of L. acidophilus in the GI tract.