Time dependence of the frequency and amplitude of the local nanomechanical motion of yeast

We report the time dependence of the local nanomechanical motion of the Saccharomyces cerevisiae (yeast) cell wall. The motion was measured under physiological conditions with an atomic force microscope over relatively extended periods of 15 seconds. The cell wall motion displayed a distinct 2-state amplitude behavior as revealed by Fourier analysis, while the frequency followed a normal Gaussian distribution centered at similar to 1.61 kHz. There was no apparent temporal relationship between either characteristic. Local motion of the bud scar on the same cell contained multiple frequencies different from that of the cell wall. Each frequency component displayed normal Gaussian fluctuations, while 1 component displayed slight 2-state amplitude behavior. The motion of the cell wall and bud scar was dependent on cellular metabolism, as confirmed by treatment with a metabolic inhibitor. The variability in frequency and amplitude of the motion provides a characteristic basis for further analysis of factors that affect the motion. (C) 2005 Elsevier Inc. All rights reserved.