Related Experiment Video
Updated: Aug 25, 2026

Live Cell Imaging of Bacillus subtilis and Streptococcus pneumoniae using Automated Time-lapse Microscopy
Published on: July 28, 2011
Stochastic processes influence stationary-phase decisions in Bacillus subtilis
Heather Maughan1, Wayne L Nicholson
1Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, Arizona 85721, USA.
Abstract:
It has recently been proposed that phenotypic variation in clonal populations of bacterial species results from intracellular "noise," i.e., random fluctuations in levels of cellular molecules, which would be predicted to be insensitive to selective pressure. To test this notion, we propagated five populations of Bacillus subtilis for 5,000 generations with selection for one phenotype: the decision to sporulate. In support of the noise hypothesis, we report that none of the populations responded to selection by improving their efficiency of sporulation, indicating that intracellular noise is independent of heritable genotype.
Related Concept Videos
Regulation of Bacterial Virulence
Bacterial Growth Curve
Coordination of Gene Expression Processes in Bacteria
Stringent Response in E. coli
Gene Regulation During Sporulation
Other Stress Responses in Bacteria

