A common public misconception is that bacteria live alone and act as solitary organisms. This misconception, however, is far from reality.
Bacteria always live in very dense communities. Most bacteria prefer to live in a biofilm, a name for a group of organisms that stick together on a surface in an aqueous environment. The cells that stick together form an extracellular matrix which provides structural and biochemical support to the surrounding cells. In these biofilms, bacteria increase efficiency by dividing labor. The exterior cells in the biofilm defend the group from threats while the interior cells produce food for the rest.
While it has long been known that bacteria can communicate through the group with chemical signals, also known as quorum sensing, new studies show that bacteria can also communicate with one another electrically. Ned Wingreen, a biophysicist at Princeton describes the significance of the discovery; “I think these are arguably the most important developments in microbiology in the last couple years, We’re learning about an entirely new mode of communication.”
An entirely new mode of communication it is! Heres how it works:
Ion channels in a bacteria cell’s outer membrane allow electrically charged molecules to pass in and out, just like a neuron or nerve cell. Neurons pump out Sodium ions and let in Potassium ions until the threshold is reached and depolarization occurs. This is known as an action potential. Gurol Suel, a biophysicist at UCSD emphasizes that while the bacteria’s electrical impulse is similar to a neuron’s, it is much slower, a few millimeters per hour compared to a neuron’s 100 meters per second.
So what does this research mean?
Scientists agree that this revelation could open new doors to discovery. Suel says that electrical signaling has been shown to be stronger than traditional chemical signaling. In his research, Suel found that potassium signals could travel at constant strength for 1000 times the width of a bacteria cell, much longer and stronger than any chemical signal. Electrical signaling could also mean more communication between different bacteria. Traditional chemical signaling relies on receptors to receive messages, while bacteria, plant cells, and animal neurons all use potassium to send and receive signals. If these findings are correct, there’s potential in the future for the development of new antibiotics.
Learning about electrical signaling in bacteria has complicated our understanding of these previously thought to be simple organisms. El Naggar, another biophysicist at USC says, “Now we’re thinking of [bacteria] as masters of manipulating electrons and ions in their environment. It’s a very, very far cry from the way we thought of them as very simplistic organisms.”