FIG 1.

Quantitative characterization of spatial organization of NTHI in biofilms formed in vivo shows a fractal structure. (A and B) Organization of NTHI (green) and DNA strands (blue) in three-dimensional (3D) renderings derived from CLSM images for biofilm section of 10-μm thickness (z direction) and a cross-section of 148 μm (x direction) by 148 μm (y direction) obtained from the chinchilla middle ear at day 4 (A) and day 11 (B) postchallenge. The black bar indicates 50 μm. (C) Variation of C_z(r)/C_z(0) with r for the spatial patterns of NTHI in the CLSM images in panel A. The z values indicate the positions of the layers along the z direction. The fits to the data with a function C_z(r)/C_z(0) = 1 − ar^θ, where a and θ as the fitting parameters, are shown in solid, dashed, and dotted lines. The fitting parameters for the data shown are the following: for z = 3 μm, a = 0.256, θ = 0.597; for z = 5 μm, a = 0.315, θ = 0.752; for z = 7 μm, a = 0.309, θ = 0.790. (Inset) Variation of ξ_z with z for the spatial patterns of NTHI in panel A. dpi, days postinfection. (D) Variation of C_z(r)/C_z(0) with r for the spatial patterns generated by the NTHI in the CLSM images in panel B. The data are fitted with the same function as in panel C. The fitting parameters are the following: for z = 3 μm, a = 0.464, θ = 0.574; for z = 5 μm, a = 0.464, θ = 0.567; for z = 7 μm, a = 0.474, θ = 0.558. (Inset) Variation of ξ_z with z for the spatial patterns of NTHI in panel B. (E) ξ_z represents a typical size of a cluster of NTHI in the CLSM images in panels A and B.