Fig. 5. Mtb forms biofilms inside the mice lungs.

a Histopathology of granulomatous lesions in the lungs of Mtb infected mice (n = 5) in contrast to uninfected ones, as indicated by H & E staining. Clusters of acid-fast bacilli are denoted by arrows. b, c CW staining and corresponding quantitation (using NIS elements) of Mtb infected, uninfected and Cellulysin Cellulase treated lung sections of mice showing Mtb bacilli (stained with Auramine B–Rhodamine O) encased within a polysaccharide-rich matrix. d The schematic construct of the CBD-mCh probe wherein the Cellulose Binding Domain (CBD) of CenA is fused to fluorescent probe mCherry through an octa-glycine linker. e, f CBD-mCh staining and quantification (using NIS elements) for the experiment described above. g DNS assay on uninfected and Mtb infected mice lungs after treatment with cellulase to check the yield of reducing sugar glucose. h Raman microscopy of (i) uninfected and (ii) Mtb infected mice lung sections showing cellulose specific peaks. The column bar graphs presented in figures c, f and g have been plotted in GraphPad Prism 6 and represented as mean (±s.e.m). Statistical significance was determined using Student’s t-test (two tailed). For c, ****P < 0.0001, for f, **P = 0.0022 and ***P < 0.0001, and for g, ***P < 0.0001. All data are representative of three independent biological experiments performed in triplicates. Scale bars correspond to 50 μm. All source data are provided as a Source Data file.