Pavlo Bohutskyi and his team explored how influencing the circadian rhythms of microbes can spur increased creation of bioproducts.
RICHLAND, Wash.—People who have disrupted circadian rhythms suffer all kinds of negative effects, including higher rates of obesity, sleep difficulties and accidents.
But in cyanobacteria—the bacteria also known as blue-green algae—disrupted rhythms can pay off for researchers seeking new ways to produce biology-based products more efficiently.
Scientists at the Department of Energy’s have demonstrated how the organism’s circadian rhythms can be used to boost production. Leaving the lights on overnight paid off with unexpected extra production of a substance of interest—in this case, sugar.
The work, completed by a team led by Pavlo Bohutskyi, is part of PNNL’s . Scientists are exploring ways to influence the traits, or phenotype, of an organism in ways that they can predict and control. The aim is to fill a gap in our understanding of the molecular world: While DNA provides the blueprint for an organism’s development, how is that genetic plan implemented? How exactly do environmental factors determine the traits of a person, cyanobacteria and other living things?
In the latest work, published in , Bohutskyi’s team studied how cyanobacteria’s circadian rhythms control carbon and energy metabolism. They manipulated cyanobacteria’s environment and then monitored the effects.
Normally, the organism soaks in sunlight during the day, carrying out photosynthesis and creating energy reserves in the form of glycogen. At nighttime, in the dark, the light-collecting machinery rests, and the organism directs its energy to restore cellular processes, carry out cell division and maintain its health.
The team altered the input to this natural rhythm, instead keeping the lights on all night in addition to the usual daytime light. Unexpectedly, the cyanobacteria went on a production binge, producing three times as much sucrose as in the daytime. Instead of resting, they used the extra light to break down their stores of energy to create sugar. They reduced the energy spent on maintaining themselves and increased the energy put forth to create a product.
In other words, the organism changed its activities in direct response to an environmental change, redirecting its energy away from its typical nighttime activities and toward an unusual nighttime activity. It’s a good example of , or traits, of an organism.
The switch occurred thanks to changes in the activity of more than 300 genes involved in photosynthesis, carbon storage, cell division and other vital processes.
“The cyanobacteria rewired themselves, essentially, in response to a change in their environment,” said Bohutskyi, who holds a joint appointment at Washington State University. “The metabolism and the phenotype of the organism have changed in a very dramatic way.”
The findings put forth a new way to boost the efficiency of cyanobacteria, which are used to produce fuels, foods and industrial chemicals. More broadly, the research demonstrates how environmental changes can rewire the molecular milieu of organisms to determine what they become and what they do.
More than 100 researchers will discuss related research during the first , organized by PNNL, to be held April 29–May 1 in Richland, Wash.
The work was funded by PNNL through the , with partial support from DOE’s Office of Science. Some molecular analyses were conducted at the Environmental Molecular Sciences Laboratory, an Office of Science user facility located at the PNNL-Richland campus.
Authors of the paper in addition to Bohutskyi are Ashley Gilliam, Natalie C. Sadler, Xiaolu Li, Marci Garcia, Zachary Johnson, Marija Veli膷kovi膰, Young-Mo Kim, Song Feng, Wei-Jun Qian and Margaret S. Cheung.
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