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
BS
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
JAN 13, 2022
Health & Medicine
Studies Confirm Omicron Itself, Not Previous Immunity From Infections or Vaccines, Is Responsible for Milder Symptoms
JAN 13, 2022
Studies Confirm Omicron Itself, Not Previous Immunity From Infections or Vaccines, Is Responsible for Milder Symptoms
Despite initial fears last November that genetic changes to the Omicron variant might spell disaster for humans, rodent ...
JAN 18, 2022
Immunology
Omicron Can't Dodge T Cells
JAN 18, 2022
Omicron Can't Dodge T Cells
The Omicron variant was first reported in November 2021. More recently, a surge of infections worldwide has led to wides ...
MAR 14, 2022
Immunology
Many Variants of the Virus Can Hide Away in COVID-19 Patients
MAR 14, 2022
Many Variants of the Virus Can Hide Away in COVID-19 Patients
Though it may happen at different rates for different microbes, mutations happen, and SARS-CoV-2, the virus that causes ...
MAR 17, 2022
Microbiology
New Molecular Injection Systems Like Spear Guns Found on Bacteria
MAR 17, 2022
New Molecular Injection Systems Like Spear Guns Found on Bacteria
There are many spectacular little machines in nature, like the injection systems found on some bacterial cells. Some mic ...
APR 20, 2022
Microbiology
Rapid AST: A key weapon in the fight against AMR
APR 20, 2022
Rapid AST: A key weapon in the fight against AMR
Despite the dire, well-documented risks of antimicrobial resistance (AMR), which threatens to kill 10 million people a y ...
APR 20, 2022
Immunology
Rare Soil Microbe Shows Promise as New Antibiotic
APR 20, 2022
Rare Soil Microbe Shows Promise as New Antibiotic
  Antibiotic resistance has increased the demand for new antibiotic treatments. Now, researchers have found that a ...
Loading Comments...