News

Ejecting flagella could help microbes save energy during nutrient depletion

Images from our data of (left) a functioning flagellar motor, and (right) a flagellar motor in the process of disassembling.

Credit: Morgan Beeby, Imperial College London

Close

In favorable conditions, many bacteria propel themselves to food sources and other sites of interest using whip-like molecular propellers known as flagella. However, according to new research published on March 19 in the open-access journal PLOS Biology, by Josie Ferreira and colleagues of Imperial College London, members of the bacterial class Gammaproteobacteria eject their flagella when nutrients are scarce.

advertisement

These findings suggest a previously unknown mechanism for microbes to save energy in lean times. Earlier research has shown that bacteria switch from a mobile to stationary phase in the face of nutrient depletion, but it has been unclear how they deactivate their large, energy-intensive flagella.

The authors of the new study used electron microscopy to get a 3-D look at Gammaproteobacteria that have one or more flagella clustered at one end of each cell. Focusing on two species, Plesiomonas shigelloides and Vibrio fischeri, they saw that microbes living in a nutrient-abundant environment had few partial flagella, but microbes in nutrient-depleted conditions had many more partial flagellar structures.

Further experiments confirmed that these partial structures were relics of flagella that had been ejected, and that a nutrient-depleted environment was indeed the trigger. So, like mountaineer Aron Ralston cutting off his own arm to avoid certain death in the film 127 Hours, bacteria cut off their own tails to avoid starvation.

Flagella are driven by tiny motors embedded in the cell membrane, so ejecting the flagella runs the risk of leaving empty motors with wide-open portals that would allow spillage of the insides of the cell into the environment. Intriguingly, the researchers found that an unidentified protein plugs up the relics of flagellar motors, and they hypothesize that this plug prevents leakage of cellular contents through the resulting hole in the cell membrane.

In the future, additional research could clarify the molecular details of the ejection process, including the identity of the plug protein.

advertisement

Materials provided by PLOS . Note: Content may be edited for style and length.

PLOS. "Ejecting flagella could help microbes save energy during nutrient depletion." ScienceDaily. ScienceDaily, 19 March 2019. .

PLOS. "Ejecting flagella could help microbes save energy during nutrient depletion." ScienceDaily. www.sciencedaily.com/releases/2019/03/190319142306.htm (accessed March 19, 2019).
Read more on sciencedaily.com
News Topics :
RELATED STORIES :
Science
The bacterial flagellum is one of nature s smallest motors, rotating at up to 60, 000 revolutions per minute. To function properly and propel the bacterium, the flagellum requires all of...
Science
Do bacteria control their walks like we do It might sound strange, but it s a fundamental question. Understanding bacteria motility would not only expand our understanding of their behavior,...
Science
A cell s plasma membrane forms a protective barrier, separating its inner contents from the outside environment. There is a pressing need to better understand the complex lipid bilayer that...
Science
A false color structure of RssB pink and cyan a protein that specifically recognizes a critical stress response master regulator in bacteria and delivers it to the recycling machinery somewhat like...
Technology
More than one in 10 people in the world lack basic drinking water access, and by 2025, half of the world s population will be living in water stressed areas, which...