Response to Comment on “A commensal strain of Staphylococcus epidermidis protects against skin neoplasia” by Nakatsuji et al.

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Science Advances  11 Sep 2019:
Vol. 5, no. 9, eaay5611
DOI: 10.1126/sciadv.aay5611


  • Fig. 1 Molecular weight of 6-HAP-MPB on the package label does not correspond to that of 6-HAP.

    (Photo credit: Teru Nakatsuji, University of California, San Diego.)

  • Fig. 2 6-HAP-MPB does not contain a chemical that is identical to 6-HAP.

    (A) 6-HAP-MPB was dissolved in 99% acetonitrile/1% TFA (trifluoroacetic acid) and subjected to high-resolution ESI-TOF-MS. Peaks were scanned between m/z 100 and 1250 in positive ion mode. (B) Estimated chemical composition of three major peaks detected in 6-HAP-MPB. None of them correspond to that of 6-HAP (theoretical mass, 151.0489).

  • Fig. 3 6-HAP has antimicrobial activity, but 6-HAP-MPB does not.

    Antimicrobial activity of indicated concentration of 6-HAP or 6-HAP-MPB was measured against group A Streptococcus (NZ131) with a radial diffusion assay. Black circle of zone of growth inhibition represents antimicrobial activity of 6-HAP (arrows). The method of this assay has been provided in our original manuscript.

  • Fig. 4 6-HAP can be spontaneously deoxidized in solution within 24 hours.

    (A and B) Native 6-HAP was dissolved in heated H2O (60°C) at 0.1 mg/ml and incubated at room temperature for 24 hours. Degradation of 6-HAP was characterized by low-resolution ESI-TOF-MS (A), followed by the high-resolution mode (B). All 6-HAP was degraded after a 24-hour incubation. (C) Estimated chemical composition of two major peaks detected in (B).

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