Fig. 2

Escherichia coli is a universal helper for the cultured helper-dependent and helper-induced strains. All strains identified in the co-culture screen were tested for induction by E. coli K12 BW25113. Identified induced strains were spread on brain heart infusion agar with 5.0 g/L yeast extract, 0.1% cysteine, and 15 mg/mL hemin (BHIych), and 5 μL of a 24-h culture of E. coli K12 BW25113 was then spotted on the same plate. a Taxonomic information on the induced isolates and their helper organisms. Different growth induction profiles were identified, including complete dependence, as observed with b Bilophila wadsworthia KLE 1795, and substantially increased colony size, as seen with c Bacteroides clarus KLE1792, d Gordonibacter pamelaeae KLE1812, e Faecalibacterium sp. KLE1255, and all other isolates (not pictured). Images are displayed in black and white to improve contrast