A novel method to study aging in bacteria that reproduce by morphologically symmetric fission

- A quantitative method is developed to detect aging of bacteria that reproduce by fission.
- The sensitivity of detection and the false positive rate are analyzed in detail.
- The method is successfully applied to cells of various magnitudes of aging in simulation.
- The proposed method is applicable to non-cylindrical cells.

The study of aging in fission bacteria has been especially difficult because of the challenge in identifying older sibling cells due to their morphological similarity to younger sibling cells. This study develops a generic method solely based on the analysis of cell growth rate (rate of cell volume increase). The proposed method does not require any special assumptions or measurements regarding the physical features of older siblings, such as older cell poles or slightly greater cell sizes. Therefore, the proposed method is applicable to the study of far more types of bacteria than those of existing methods. Bacteria that can be examined using this method include, but are not limited to, the following categories: (1) cocci bacteria in which tracking a larger number of old pole cells through successive generations is formidable, (2) possible bacteria where cell poles are either weakly correlated or uncorrelated to aging, and (3) bacteria that reproduce by multiple-fission. This new method provides a useful tool to study the relationship between cell poles and aging in bacteria.