OCT 23, 2018 7:44 AM PDT

DNA Pumps up Bacterial Cells

WRITTEN BY: Carmen Leitch

Cells are the basic building blocks of life, and have been well-studied since they were discovered in 1655. There are many different structures in the cell and even more molecules and chemicals that make it all work, and many of them are still a mystery to us. Researchers continue to study the basic processes of life in cells, and often those discoveries have unexpected applications. New work by scientists at UC San Diego and Imperial College in London has identified a surprising role for the DNA of bacterial cells.

Cryo-electron tomography images of a forespore inflated by DNA (left) and of a deflated forespore in the absence of DNA (right). The membranes are highlighted in pink and purple. / Credit/Copyright: UC San Diego

Reporting in Cell, researchers Javier Lopez-Garrido, Kit Pogliano and colleagues used the bacterium Bacillus subtilis to show that DNA doesn’t only provide the blueprint for everything in the cell to be made. It also provides architectural support, pumping up the bacterium.

"Our study illustrates that DNA acts like air in a balloon, inflating the cell," said Lopez-Garrido, an assistant research scientist in UC San Diego's Division of Biological Sciences and the study's first author. "DNA is best known for being the molecule with genetic information but it's becoming more and more obvious that it does other things that are not related to that."

Their work, said the researchers, may have applications for human cells; it may reveal more about how our cells are formed and shaped, and it could provide insight into mechanical processes and the structure of organelles like the nucleus and mitochondria.

Modern bacterial cells, noted Lopez-Garrido, can control their internal pressure. This data could help scientists understand the origins of cellular life since these internal control mechanisms were absent from primitive cells when life first arose on the planet. This study may be showing us more about how those first cells worked.

"Biologists tend to think of cell growth as following normal, biosynthetic pathways, but we found a pathway that is not normal, as it does not depend on processes normally required for growth," said the senior author of the study Kit Pogliano, a professor in the Section of Molecular Biology. "All you need for this cell to grow is to inflate it with DNA and its associated positively charged ions, and the ability to make more membrane so the cell can get bigger. Nothing else seems to be required."

With a fluorescent microscope that could take time-lapse images, B. subtilis cells could be tracked through sporulation, as they formed. As the process went on, the cell split into a mother and forespore - a smaller cell. Cryo-electron tomography showed that mother cells were inflating the forespore with DNA, stretching and swelling the little cell until a new cell was formed (as seen in the video - the membrane is red, DNA is green).

"It's amazing how we are just beginning to scratch the surface of how physics impacts living organisms," said Pogliano. "This is a unique example of a very simple biophysical property impacting cell shape, and it illustrates the value of physicists working closely with biologists. Understanding how physics and biology intersect is a huge area for future growth."

ASM profiles the Pogliana lab in the video.

 

Sources: AAAS/Eurekalert! via UCSD, Cell

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
AUG 24, 2020
Immunology
Injectable Drug Stops HIV From Entering Cells
AUG 24, 2020
Injectable Drug Stops HIV From Entering Cells
Once in the body, HIV tracks down T cells that bear the CD4 receptor. It attaches to these immune cells, fusing itself w ...
SEP 02, 2020
Microbiology
A Common Bacterium Can Evolve in the Stomach
SEP 02, 2020
A Common Bacterium Can Evolve in the Stomach
Helicobacter pylori can be found in as much as fifty percent of the world's population.
SEP 04, 2020
Microbiology
Researchers Discover a Way to Use Microbes to Help Make Plastic
SEP 04, 2020
Researchers Discover a Way to Use Microbes to Help Make Plastic
Researchers have discovered that some bacteria can make ethylene in a way we never knew about; microbes that metabolize ...
OCT 13, 2020
Microbiology
Bacterial Biofilms Can Take on Some Animal-Like Characteristics
OCT 13, 2020
Bacterial Biofilms Can Take on Some Animal-Like Characteristics
Bacteria are everywhere, even inside of our bodies, and they are thought to date back to the early days of life on Earth ...
NOV 15, 2020
Microbiology
Monitoring a Virus in Real-Time as it Infects a Cell
NOV 15, 2020
Monitoring a Virus in Real-Time as it Infects a Cell
Hubrecht Institute researchers observe a virus as it invades a cell and competes with the host for control of the host c ...
NOV 15, 2020
Neuroscience
Researchers Confirm Link Between Alzheimer's and Gut Bacteria
NOV 15, 2020
Researchers Confirm Link Between Alzheimer's and Gut Bacteria
Researchers from the University of Geneva in Switzerland have confirmed the link between an imbalance of gut bacteria an ...
Loading Comments...