Figure 1. Thoeris provides anti-phage protection in staphylococci.

(A) Schematic of the Thoeris operon present in the Staphylococcus aureus strain 08BA02176. The operon includes a thsA gene harboring a STALD domain, and two thsB genes, thsB1 and thsB2 that encode TIR domains. (B) Tenfold serial dilutions of different staphylococcal phages on lawns of S. aureus RN4220 harboring plasmids carrying either an incomplete (thsB1/B2) or full (thsA/B1/B2) Thoeris operon. (C) Growth of S. aureus RN4220 harboring plasmids carrying either an incomplete (thsB1/B2) or full (thsA/B1/B2) Thoeris operon, determined as the OD₆₀₀ of the cultures after infection with Φ80α-vir at MOI 1. Mean of +/− S.D. of three biological replicates is reported. (D) Same as (C) but following the growth of lysogenic cultures after induction of the Φ80α prophage with MMC. (E) Enumeration of PFU/ml after induction of the Φ80α prophage with MMC present in lysogens harboring plasmids carrying different combinations of the thsA, thsB1 and thsB2 genes. Dotted line indicates the limit of detection. Mean of +/− S.D. of three biological replicates is reported; p value was obtained using an unpaired, two-tailed, t-test. (F) Measure of % remaining NAD+ and NADH (NAD), calculated as the ratio of the concentration of NAD+ and NADH detected in staphylococci harboring plasmids carrying different combinations of the thsA, thsB1 and thsB2 genes, to the value detected in the absence of any of the ths genes, after induction of the Φ80α prophage with MMC. Mean of +/− S.D. of three biological replicates is reported; p value was obtained using an unpaired, two-tailed, t-test. (G) Fluorescence microscopy of S. aureus RN4220 harboring plasmids carrying either an incomplete (thsB1/B2) or full (thsA/B1/B2) Thoeris operon. Images were taken every two hours after infection with Φ80α-vir-GFP phage, up to eight hours. The images are representative of three independent experiments.