Bacteria come in all shapes and sizes some are straight as a rod, others twist like a corkscrew. Shape plays an important role in bacteria infiltrate and attack cells in the body. The helical shape of Helicobacter pylori, a species of bacteria which can cause ulcers, may help it penetrate tissues.
Bacteria have an extraordinary ability to maintain and recover their morphology even after being twisted out of shape. That shape determined by the cell wall, yet little known about how bacteria monitor and control it. Since, the cell wall is the target of most antibiotics, understanding how bacteria grow their cell walls provide insight into more effective medicines.
Now, a team of researchers from Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) has found that Escherichia coli (E. coli) may use mechanical cues to keep their shape.
In previous research, researchers observed similar bending forces bacteria become plastically deformed, means when the bending force removed, E. coli cells snapped back to a straighter, but still bent shape. This suggested that cell wall growth could sense the applied bending force. Researchers also found that the cells straightened upon further growth.
In the latest research, the team explored how the bacterium compressed or stretched could explain the snap back and predict how fast the bacteria would straighten when released.
Researchers have answered this question with a theoretical model which quantitatively predicted both how the bacteria would grow to recover its straight shape and how long it would take.
The models and experiments were consistent with each other. A mechanical strain-dependent cell wall growth rate predicted a straightening rate consistent with what found experimentally.
Felix Wong, a graduate student at SEAS, said, our proposed idea for bacteria is reminiscent of plant growth, said Wong. Our research shows the same may true for bacteria. However, if mechanical strains were indeed an important sensory cue for bacteria, then there must be a molecular mechanism that senses mechanical strain.
More information: [Nature Microbiology]