************ The 9th Lab Seminar ***************************************

Title : Bacterial Chromosomal Loci Move Subdiffusively through a 
Viscoelastic Cytoplasm
(Stephanie C. Weber, Andrew J. Spakowitz and Julie A. Theriot, Physical 
Review Letters, 104, 238012 (2010))

Speaker : NOGUCHI Takafumi

Date : Fri. Nov. 16th, 1:30 pm

Abstract :
Tracking of fluorescently labeled chromosomal loci in live bacterial 
cells reveals a robust scaling of the mean square displacement (MSD) as 
Ą^(0.39). We propose that the observed motion arises from relaxation of 
the Rouse modes of the DNA polymer within the viscoelastic environment 
of the cytoplasm. The time-averaged and ensemble-averaged MSD of 
chromosomal loci exhibit ergodicity, and the velocity autocorrelation 
function is negative at short time lags. These observations are most 
consistent with fractional Langevin motion and rule out a continuous 
time random walk model as an explanation for anomalous motion in vivo.


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