Stanford research leads to new understanding of how cells grow and shrink

By Tom Abate

Video shows shocked cells expanding rapidly to a size roughly equivalent to cells growing at full speed in normal solutions.

For a century biologists have thought they understood how the gooey growth that occurs inside cells causes their protective outer walls to expand. Now, Stanford researchers have captured the visual evidence to prove the prevailing wisdom wrong. The finding may lead to new strategies for fighting bacterial diseases.

"What we observed was not what we had expected," said K.C. Huang, an assistant professor of bioengineering and of microbiology and immunology and the senior author of the findings, which were published online May 12 in the Proceedings of the National Academy of Sciences.

The research paper, which describes a process known as "osmotic shock," was co-authored by Julie Theriot, a professor of biochemistry and of microbiology and immunology at Stanford School of Medicine.

The researchers believe their discovery about the surprising resilience of cell wall growth may help explain why seemingly fragile bacteria such as E. coli can thrive in environments as different as puddles and stomachs.

Enrique Rojas, a postdoctoral scholar in bioengineering, and the lead author of the PNAS article, is now in Bangladesh trying to apply this knowledge to help fight cholera.

Gurol Suel, an associate professor of molecular biology at the University of California, San Diego, who was not involved in the work, hailed the discovery as "a paradigm shift."

"Just because a hypothesis has been around for decades does not necessarily imply that it is correct," Suel said, adding that the link between internal pressure and cell growth had emerged from less sophisticated experiments, while the Stanford team used modern techniques to "provide a new molecular understanding of bacterial cell growth."

Cells, the basic structural units of all life, were first observed more than 400 years ago after the invention of the microscope. One of the most studied cells in science is E. coli, a sausage-shaped bacterium that lives in the intestine.

Continue reading here:
Stanford research leads to new understanding of how cells grow and shrink