Mechanical crack propagation drives millisecond daughter cell separation in Staphylococcus aureus

See allHide authors and affiliations

Science  01 May 2015:
Vol. 348, Issue 6234, pp. 574-578
DOI: 10.1126/science.aaa1511

Pop goes the coccus

Daughter cell separation in Staphylococcus aureus proceeds much like the cracking of an egg. So say Zhou et al., who examined dividing cells with millisecond precision using high-speed videomicroscopy. Rather than proceeding gradually, tiny imperfections in the mother cell wall were seen to crack open, leaving two daughter cells linked by a hinge.

Science, this issue p. 574


When Staphylococcus aureus undergoes cytokinesis, it builds a septum, generating two hemispherical daughters whose cell walls are only connected via a narrow peripheral ring. We found that resolution of this ring occurred within milliseconds (“popping”), without detectable changes in cell volume. The likelihood of popping depended on cell-wall stress, and the separating cells split open asymmetrically, leaving the daughters connected by a hinge. An elastostatic model of the wall indicated high circumferential stress in the peripheral ring before popping. Last, we observed small perforations in the peripheral ring that are likely initial points of mechanical failure. Thus, the ultrafast daughter cell separation in S. aureus appears to be driven by accumulation of stress in the peripheral ring and exhibits hallmarks of mechanical crack propagation.

View Full Text

Stay Connected to Science