KENBIKYO Vol.50▶No.2 2015
■Feature Articles: ‌Novel Insights and Perspectives in Microbiology Obtained from Time-Lapse and Spatial Serial Observation of Single Bacterial and Yeast Cells

Adaptive Roles of Phenotypic Fluctuation and Single-Cell Statistics

Yuichi Wakamoto

Abstract: Clonal heterogeneity of phenotypic traits is often associated with the fitness differences of single cells. Fitness-phenotype correlation causes the population statistics for the phenotypes of interest deviated from the single-cell statistics, imposing fundamental uncertainty in estimating the cellular properties from the population measurements. Recently, microfluidics-based single-cell measurement has become available, which potentially allows us to understand how the population properties are shaped by the heterogeneous and fluctuating single-cell phenotypes. To introduce this issue, we first review the studies on bacterial persistence, in which phenotypic heterogeneity has an apparent relevance to cellular fitness and population survival in stress environments. Next, we discuss how the population-level statistics is biased by the phenotype-fitness correlation using a simple cell proliferation model. Lastly, we show that the experimental examples of single-cell statistics and phenotype-fitness correlation are accumulating by the aid of the novel microfluidics techniques.

Key words: Single-cell measurement, microfluidics device, bacterial persistence, phenotype-fitness correlation, Single-cell statistics