Fig. 3. Phenotypic characterization of FM2.5. Phenotypic characterization of FM2.5. (A and B) Cultures of R20291, FM2.5, and FM2.5RW were challenged with lysozyme (500 μg/ml) (A) or LL-37 (5 μg/ml) (B) in exponential phase after 2.5 hours (indicated with arrows). Untreated control cultures were grown in parallel. Experiments were carried out in triplicate on biological duplicates. Means and SDs are shown. (C) Sporulation of R20291, FM2.5, and FM2.5RW after 5 days. Spore CFUs were determined after a standard 65°C heat treatment for 30 min or a harsher 75°C heat treatment for 30 min. Heat-resistant spore CFUs are expressed as a percentage of total viable CFUs (spores and vegetative cells). Experiments were carried out in triplicate on biological duplicates. Means and SDs are shown. *P < 0.01, determined using two-tailed t tests with Welch’s correction. (D) Germination of R20291, FM2.5, and FM2.5RW spores. Synchronous germination of purified spores was induced with the bile salt taurocholate. Germination initiation was monitored by measuring the resulting decrease in OD600nm. Joseph A. Kirk et al., Sci Transl Med 2017;9:eaah6813 Published by AAAS