Fig. 3
Absolute abundance (cells mL.−1) of the most abundant genera and species (represented as OTU trend lines) varied with SHIME transit time in the proximal and distal colon region (n = 30). Only significant OTUs with a relative abundance of more than 5% within the genus were shown. Short, medium and long SHIME transit times were 8, 16 and 24h in the proximal colon and 13, 26 and 39h in the distal colon. Statistically significant differences between SHIME transit times are indicated by the letters a, b and c (unpaired two-sided Wilcoxon signed rank tests with Holm correction). Identical letters indicate no significant differences (PFDR > 0.05). Significant differences between colon regions are indicated with asterisks (*) (PFDR < 0.05, paired two-sided Wilcoxon signed rank tests with Holm correction). Spearman’s rank correlation coefficients (ρ) and corresponding PFDR-values (*PFDR < 0.05, **PFDR < 0.01, ***PFDR < 0.001, ****PFDR < 0.0001) were only calculated for monotonic relationships including only the donors carrying the taxon of interest. Higher level taxa are to be interpreted as unclassified genus belonging to the respective taxon. Box plots display individual data points, as well as the interquartile range, median and outliers beyond the 1.5 times interquartile range (whiskers)