Ultrasonic measurements in Escherichia coli at various growth stages

The ultrasonic parameters were carried out at a frequency of 2 MHz using pu lse echo overlap (PEO) technique on Escherichia coil grown in nutrient brot h at a constant temperature of 37 degreesC. The values of acoustic impedanc e (Z), isotropic compressibility (K-s) and attenuation coefficient (alpha) were calculated from measured values of ultrasonic velocity (upsilon), echo -amplitudes (a(n)) and density (rho). The ultrasonic velocity values were c orrelated with Jacobson's [Acta Chemica Scandi. 5 (1951) 1214 and 6 (1952) 1927] free length theory (FLT). The variation of ultrasonic parameters with the time of growth of bacteria has been interpreted on the basis of motili ty, shape and size of the bacteria in this publication. (C) 2001 Elsevier S cience B.V. All rights reserved.