JUN 20, 2021 9:03 AM PDT

Bacteria Can Shape-Shift to Survive in Different Conditions

WRITTEN BY: Carmen Leitch

Escherichia coli bacteria are known to live in the gut, and they can also sicken people if they contaminate food that gets eaten. These bacteria can easily survive in many different environments, including those with a scarcity of nutrients. The bacteria are able to go through a gastrointestinal tract and then onto their next destination, like a toilet bowl, and can live through it all. Researchers at Washington University in St. Louis (WUSTL) wanted to know how these tenacious microbes do it.

E. coli cells go from nutrient-rich (left) to nutrient-free conditions (right). The cytoplasm (green) and the periplasm (red) can be seen. / Credit: Kerwyn Casey Huang laboratory, Stanford University

They took a close look at E. coli that had been starved, which can be done in a lab and is known to cause alterations in bacteria. The researchers observed changes in the physical appearance of the microbes; they thought that this is related to the survival of the cells.

"Their cytoplasm shrank. As it shrank, the inner membrane pulled away from the outer membrane and left a big space at one end of the cell," said Petra Levin, professor of biology in Arts & Sciences at WUSTL.

The space that's between the inner and outer membrane of bacteria is called the periplasm. The research team found that when E. coli cells were starved, the cytoplasm of the got more concentrated and dense, which is likely due to water loss. The space between the membranes also began to get larger while the inner membrane pulled away from the outer membrane. The findings have been reported in the Proceedings of the National Academy of Sciences.

"Although we don't know for sure yet, we think that the cell is concentrating the nutrients in the cytoplasm so that it can keep running metabolism at a high rate," Levin suggested. "Perhaps this is an adaptation to E. coli's constantly and rapidly changing lifestyle, in which it knows that each environment is temporary."

This physical change in the bacteria could also be reversed. When the researchers put the starved bacteria into a medium that was rich in nutrients, the cytoplasm increased in volume and the inner membrane expanded. The cells rebounded quickly from a state of starvation, especially when the E. coli were fed glucose, a sugar they thrive on.

The researchers also found that after they gave the bacteria nutrients again, the Tol-Pal system was intact. This system is made of proteins that link the inner and outer membrane, and is a crucial part of the cell. But researchers don't know everything about it.

The study authors suggested that the Tol-Pal system helps reconnect the inner membrane to the outer membrane. Without the system, the cells will lose their internal contents.

"We speculate that Tol-Pal acts as the zipper slider, helping the inner membrane zip into the outer membrane coat during recovery," Levin said. The researchers are planning to continue investigating these phenomena.

Sources: AAAS/Eurekalert! via Washington University in St. Louis, Proceedings of the National Academy of Sciences

About the Author
  • Experienced research scientist and technical expert with authorships on over 30 peer-reviewed publications, traveler to over 70 countries, published photographer and internationally-exhibited painter, volunteer trained in disaster-response, CPR and DV counseling.
You May Also Like
MAY 03, 2021
Cell & Molecular Biology
Are Retrons the Next CRISPR?
MAY 03, 2021
Are Retrons the Next CRISPR?
After being identified in the 1980s, it was thought that retrons were just an odd feature of some bacterial cells. But e ...
MAY 16, 2021
Cell & Molecular Biology
Another Piece of the Lyme Puzzle is Solved
MAY 16, 2021
Another Piece of the Lyme Puzzle is Solved
Over the past 20 years, Lyme has gone from a virtually unknown disease to the most reported vector-borne illness in the ...
MAY 23, 2021
Microbiology
Move Over Bacteria, Make Way for Protists
MAY 23, 2021
Move Over Bacteria, Make Way for Protists
In the world of microbes, organisms like viruses and bacteria get a lot of attention. But researchers are beginning to s ...
JUN 21, 2021
Microbiology
In a Blow to Enzyme Latch Theory, Soil Microbes Break Down Polyphenols
JUN 21, 2021
In a Blow to Enzyme Latch Theory, Soil Microbes Break Down Polyphenols
Microbes have many connections to humans. Gut microbes have a major influence on our health. For example, when we eat fr ...
JUN 24, 2021
Microbiology
New Species of Fungi Found Growing From Ancient Ant
JUN 24, 2021
New Species of Fungi Found Growing From Ancient Ant
Scientists have discovered an unusual specimen of fungus that is making a carpenter ant its home; this discovery is the ...
JUL 13, 2021
Microbiology
Expanding Viral Populations May be More Adaptable Than We Knew
JUL 13, 2021
Expanding Viral Populations May be More Adaptable Than We Knew
In nature, growing populations from bacterial colonies to humans tend to expand. In pulled expansions, the individuals a ...
Loading Comments...