Fast growing bacteria cells do not have time to copy their whole DNA before they divide again. This means that there are several copying processes ongoing at the same time in a bacteria. Researchers at SciLifeLab / Uppsala University headed by Johan Elf have used a combination of microfluidics and image analysis of E. coli with fluorescent labels on the replication machinery to study how the replication and division cycles are coupled in individual cells.
The group saw that all cells initiate at a constant volume per chromosome. The time from initiation to division is given by the individual cells growth rate, which is variable and is the major cause of the variation in cell sizes. The new results are applicable to e.g. antibiotics research where the understanding of the bacteria growth is central.