TABLE 1.

Pairwise comparison of R₀ of planktonic staphylococci, F_LR, and the dimensions of ellipsoidally deformed bacterial cells from matching experimental and theoretically calculated Lifshitz-Van der Waals forces for wild-type S. aureus NCTC 8325-4 and ATCC 12600 and their isogenic Δpbp4 mutants^e

S. aureus strain	R0 (nm)a	FLR (nN)b	kb	rLW (nm)b	RLW (nm)b	R0 − rLW (nm)b	rheight image (nm)c	R0 − rheight image (nm)b
NCTC 8325-4
Parent strain	618 ± 35	−0.8 ± 0.2	3 ± 1				638 ± 44
Δpbp4 mutant	570 ± 38	−2.7 ± 0.3		304 ± 97	780 ± 202	266 ± 135	508 ± 40d	82 ± 78
ATCC 12600
Parent strain	678 ± 38	−0.5 ± 0.1	3 ± 1				690 ± 31
Δpbp4 mutant	620 ± 33	−1.6 ± 0.4		327 ± 99	854 ± 197	293 ± 132	583 ± 27d	49 ± 60

^aData after the plus-or-minus signs indicate standard deviations in hydrodynamic radii over nine aliquots taken from three separate bacterial cultures of each strain.

^bData after the plus-or-minus signs indicate standard deviations calculated by error propagation.

^cData after the plus-or-minus signs indicate standard deviations in the height of bacterial cells over at least 60 staphylococci taken from three different cultures of each strain.

^dThe polar radius (r_{height image}) determined in the AFM peak force-QNM mode is significantly smaller than the hydrodynamic radius (R₀) measured by DLS, according to a one-sided Student's t test (P < 0.05).

^eFor an explanation of the dimensional parameters, see Fig. 1. The deformation of the bacterial cell is expressed in terms of the difference between the hydrodynamic radius and the polar radius, i.e., (R₀ − r_LW) and (R₀ − r_{height image}), in which r_{height image} is obtained from AFM imaging. For the shaded cells, results could not be calculated due to the assumption of undeformable wild-type strains.