Fracture mechanics modeling of popping event during daughter cell separation

Abstract

Most bacteria cells divide by binary fission which is part of a bacteria cell cycle and requires tight regulations and precise coordination. Fast separation of Staphylococcus Aureus (S. Aureus) daughter cells, named as popping event, has been observed in recent experiments. The popping event was proposed to be driven by mechanical crack propagation in the peripheral ring which connected two daughter cells before their separation. It has also been shown that after the fast separation, a small portion of the peripheral ring was left as a hinge. In the article, we develop a fracture mechanics model for the crack growth in the peripheral ring during S. Aureus daughter cell separation. In particular, using finite element analysis, we calculate the energy release rate associated with the crack growth in the peripheral ring, when daughter cells are inflated by a uniform turgor pressure inside. Our results show that with a fixed inflation of daughter cells, the energy release rate depends on the crack length non-monotonically. The energy release rate reaches a maximum value for a crack of an intermediate length. The non-monotonic relationship between the energy release rate and crack length clearly indicates that the crack propagation in the peripheral ring can be unstable. The computed energy release rate as a function of crack length can also be used to explain the existence of a small portion of peripheral ring remained as hinge after the popping event.

Overlapping and essential roles for molecular and mechanical mechanisms in mycobacterial cell division

“…Millisecond bacterial cell division, visualized as abrupt spatial reorientation of newborn daughter cells, has been observed by fast optical imaging of Staphylococcus aureus 6 . In their pioneering study, Zhou et al 6 linked division of S. aureus to a fracture process and postulated that it might result from stress accumulation and mechanical failure of the cell wall, thereby laying the groundwork for viewing bacterial cell division from the perspective of physical forces 32 . Their observations are reminiscent of the "V-snapping" model of cell division in M. smegmatis 33 ; more recently, additional bacterial species have been identified that also undergo abrupt spatial reorientation during cell division 7 (see Figure 4a).…”

Controllable bistable smart composite structures driven by liquid crystal elastomer

“…The spores dispensing of fern sporangium results from the sudden appearance of cavitation in cells [17,18]. Fracture propagation leads to the fast-popping event during daughter cell separation cell [19]. The snap trap of the Venus flytrap results from snap-through instability and bistable property of the leaves structures [13].…”