Nanomechanical properties of bacteria investigated in 1 mM KNO3.Deflection images (first column), elasticity maps (scale 0–20 MPa) (second column) and Young modulus distributions (third column) obtained in 1 mM KNO3 solution for a) E2152 b) E2146 c) E2302 d) E2498. Young modulus distributions were calculated within the spatial range marked by the white window positioned in the corresponding elasticity map (n = 256 force curves). Elastic (Young) moduli and bacterial spring constants were extracted from typical force-indentation curves shown in insets: open symbols are raw AFM data, solid lines stand for theoretical fits according to eq 5 (blue color, Hertzian non-linear regime) and straight lines represent fits on the basis of eq 4 (red color, linear or compliance regime associated to Turgor pressure contribution).
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