For two consecutive weeks, Sarah Hurley slept in her car parked outside her working lab.
The doctoral research assistant’s focus was on cyanobacteria, a single-celled organism that has been found in nearly every large body of water on Earth for over two billion years.
Because culturing cyanobacteria requires frequent monitoring, Hurley returned to the University of Colorado Boulder’s Sustainability, Energy and Environment Laboratory building on East Campus every three hours for 14 days to check on its growth.
“By the end of those two weeks, I was no longer a person,” she said. “I would go in and instead of driving between my house in north Boulder and back to (assistant professor) Jeff’s (Cameron) lab on campus, I would put my sleeping bag in my car because it was easier to just roll out of bed and go check on the cultures.”
The project’s genesis began in 2017 as a proposal for Hurley’s post-doctoral project. Along with Cameron and another CU Boulder assistant professor Boswell Wing, the trio’s goal was to discover if ancient cyanobacteria held similar characteristics to what is found today. In current times, cyanobacteria is more commonly known as “blue-green algae” and is the toxic substance found in many local reservoirs.
An answer was soon found when the group compared modern beta-cyanobacteria with a genetically modified form of cyanobacteria that lacked carboxysomes, a protein-lined compartment that allows the concentration of carbon dioxide. They discovered that the altered cyanobacteria actually mimicked current forms of beta-cyanobacteria. She said the results were “counterintuitive.”
“We thought that because CO2 levels were higher (today), essentially that these genetically engineered cyanobacteria would be more like ancient cyanobacteria,” Hurley said. “The breakthrough came when we had the data from the two different types of cyanobacteria and we compared that to the record two billion years ago and saw that modern-like cyanobacteria were responsible for this record.”
Although scientists have not discovered what the cyanobacteria may have looked like two billion years ago, it still holds an important lens into Earth’s history.
“What Sarah’s work showed is that basically cyanobacteria got as good as they were ever going to get two billion years ago,” Wing said. “That to me is pretty remarkable.”
Wing added that the project’s results will allow scientists to experiment on and understand how ancient cyanobacteria operated two billion years ago.
The group’s four years of hard work was rewarded on Jan. 6 when their study was published in the scientific journal, Science Advances. Although the journal requires a publishing fee, Cameron said it was important for them to reach a large audience.
Another rewarding aspect of the venture was the “unusual” alliance between CU Boulder’s geology and biochemistry departments, Wing said. His expertise focuses on biogeology while Cameron and Hurley specialize in chemistry.
“If there was from my perspective a hurdle that we had to get over, part of it was just figuring out how to talk to each other about the same things and (to) use the same vocabulary and then decide what were the interesting questions to study,” Wing said.
To help the researchers, biochemistry graduate student Nicholas HIll and then-undergraduate research assistant Claire Jasper joined the project. Hill’s contribution focused on the molecular genetics of producing the cyanobacteria, which was then given to Jasper who helped culture it.
“This project had a ton of different elements to it,” Hurley said. “There (was) modeling and measurements and culturing and each of those parts of the project probably took six months on their own. Seeing it all come together was really gratifying.
