Published: April 13, 2015 By
Joel Kralj is using fluorescent proteins to reveal how bacterial use electricity to stay alive.

Searle Scholars Award winner is cracking the code on bacterial voltage

Electric voltage powers life – Our brains use electrical transients to process every thought; every heartbeat arises from voltage changes in heart cells. Despite its importance, voltage changes in bacteria were never really studied because the cells were just too small to measure. In fact, biologists historically assumed that these voltage changes were only present in plants and animals. BioFrontiers Institute faculty member, Joel Kralj, an Assistant Professor in Molecular, Cellular and Developmental Biology, developed a method to encode a fluorescent protein into bacterial cells that allow it to become visible, revealing how bacteria use electricity to stay alive.

“Voltage really is everywhere, and life has harnessed it for billions of years in order to evolve. That’s what is amazing,” says Kralj. “Finding these electrical transients in bacteria gives us an entirely new perspective on their evolution.”

Kralj recently became a Searle Scholar for his work on voltage in bacteria. The Searle Scholars Program supports the research of scientists who recently started their appointments at the assistant professor level, and who are in their first tenure-track position at one of 153 participating academic or research institutions. Kralj was one of 15 researchers who were named Searle Scholars this year. As part of this award, he will receive $100,000 per year for three years to support his research.

The evolutionary story of bacteria is interesting enough but Kralj is looking at how bacteria use voltage changes to access hosts or signal other bacteria to colonize a host. The equipment he uses is highly specialized with fluorescent monitors developed specifically for use in bacteria, and a laser microscope to measure the tiny changes in voltage. Kralj’s lab is relatively new. He joined BioFrontiers last year and is in the process of staffing for his research. He is looking forward to using the funds from the Searle Scholars program to build more equipment to do bacterial research, including automatic scanning microscopes.

Although his research subjects are small, Kralj’s research has the potential to make a big impact. He is unlocking the secrets around how bacteria are using voltage to survive antibiotic exposure. He’s hoping to discover whether many of the antibiotic resistant “superbugs” are staying alive because they are modulating their voltage to attack hosts, colonize and evade the drugs developed to kill them. If Kralj finds this to be the case, he hopes to understand how voltage could be inhibited in bacterial cells so that antibiotic drugs could be more effective.

“The Searle Scholar grants are going to give me the flexibility to follow a lead in this research,” says Kralj. “Researchers looked for twenty years to find a way to measure this voltage, and now that we can measure it, there is so much to study.”

The University of Colorado in Boulder currently has six other Searle Scholars, including Natalie Ahn, Min Han, Arthur Pardi, Roy Parker, Gia Voeltz and Ding Xue.