Fig. 3.

Amino acids enhance the production of ϕV1/7. (A) ϕV1/7 production in defined medium containing varying concentrations of d-glucose as the sole carbon source. (B) ϕV1/7 levels determined by plaque assay in the presence of increasing concentrations of casamino acids in BHI. (C) Quantification of ϕV1/7 particles after the addition of 1% casamino acids (+CA), a defined mixture of purified amino acids (+AA), or no addition. (D) Cell density growth curve of E. faecalis grown in BHI or BHI supplemented with CA or AA. ϕV1/7 numbers are represented as pfus per 10⁶ E. faecalis cells. Statistical analysis was performed using a two-tailed Student t test with a Mann–Whitney correction. Error bars ± SEM. *P < 0.05, **P < 0.005. n = 3–5 experiments performed in duplicate.