Fig 1. The effect of Zn restriction on animal survival, bacterial burden and tissue Zn abundance.

(A) Survival of Zn-restricted or Zn-replete mice following intranasal challenge with 1 × 10⁷ CFU of S. pneumoniae strain D39. Data represent analyses of seven mice with statistical analyses performed using a Log-rank (Mantel-Cox) test. Enumeration of S. pneumoniae from host niches, nasopharynx (B), pleural lavage (C), lung (D), blood (E), following intranasal challenge with 1 × 10⁷ CFU of strain D39 (n ≥ 7). Colonisation was examined at 24 and 36 hrs post challenge in Zn-restricted or Zn-replete mice. Data represent the mean (± S.E.M.) of four independent experiments with statistical analyses performed by a one-way ANOVA. Determination of murine niche Zn abundance, nasopharynx (F), pleural lavage (G), lung (H), blood serum (I), prior to infection, or 24 hrs or 36 hrs post infection in both dietary groups (n ≥ 5) by ICP-MS. Data represent the mean (± S.E.M.) of four independent experiments with statistical analyses performed by a one-way ANOVA. Spatial distribution of Zn in the lungs of naïve Zn-restricted (J), or infected Zn-restricted (K) mice, and naïve Zn-replete (L) or infected Zn-replete (M) mice at 36 hrs post challenge. These data are representative elemental maps of murine tissue sections from analyses of at least three distinct murine samples (n ≥ 3) by laser-ablation-ICP-MS with quantitated regions of interest (ROI) highlighted. Mean (± S.E.M.) elemental data for the distinct tissue sections is presented in S2 Table. The scale bar represents a heat map (blue to red) for the intensity of Zn from 0 to 10.0 μg.g^-1.