Research on the heterogeneity of a Micrococcus luteus culture during an extended stationary phase: Subpopulation separation and characterization

摘要

After prolonged starvation, a population of stationary-phase Micrococcus luteus cells (containing dormant cells, as shown earlier) was investigated using a flow cytometer and the method of distributing cells in a two-phase system composed of aqueous solutions of polymers. Flow cytometry revealed the existence of two cell subpopulations distinguished by their ability to bind the fluorescent probe rhodamine 123. In the two-phase system, the two subpopulations were located in the polyethylene glycol (PEG) phase at the interface. The cell subpopulation with enhanced fluorescence, isolated with a cell sorter, contained viable (colony-forming) cells and dormant cells which could be resuscitated. Most viable cells stayed in the PEG fraction. Electron microscopy showed that the PEG fraction predominantly contained intact cells. [References: 20]