Association of specific phylotypes with walnut consumption and carcinogen exposure (Study 2). Association of specific phylotypes with walnut consumption and carcinogen exposure (Study 2). A, the OTU abundance was log-transformed to plot the cluster heatmap after normalization to the same sequence depth. Cluster analysis was performed using Euclidean distance and Ward method. Rows indicate OTUs. Columns indicate samples. Samples from different group were indicated by the color bar above the heat map (olive, NaCl-walnut 0%; silver, NaCl-walnut 7%; maroon, AOM-walnut 0%; red, AOM-walnut 3.5%; orange, AOM-walnut 7%; yellow, AOM-walnut 14%, navy, female; aqua, male). The heatmap shows a gradient color scale from red, indicating value = 0, to faint yellow, indicating value = 8 (color key on the top right). The samples from different group and gender were clearly separated. A total of 9 OTU clades were observed and indicated by characters in the tree on the left. The abundance of major OTU clusters responding to carcinogen exposure and walnut consumption (the abundance of clades was log-transformed). B, abundance of OTU cluster E in different groups. C, abundance of OTU cluster F in different groups. D, abundance of OTU cluster I in different groups. Differing letters (L/M/H) denote significant differences as determined by a one-way ANOVA among groups of AOM-treated mice fed different walnut concentrations. #, significant differences when comparing the vehicle-treated group with the carcinogen-treated group at the same 0% walnut level and gender-matched. #, P < 0.05; ##, P < 0.01. *, a significant difference between the 0% walnut group and 7% walnut group, gender-matched, and vehicle-treated. *, P < 0.05; **, P < 0.01. Masako Nakanishi et al. Cancer Prev Res 2016;9:692-703 ©2016 by American Association for Cancer Research