Cyanobacteria, one of the oldest types of bacteria that can perform photosynthesis, have been discovered to manage their genes in a manner similar to how AM radio transmits signals.
Cyanobacteria, an ancient lineage of bacteria that perform photosynthesis, have been found to regulate their genes using the same physics principle used in AM radio transmission.
Recent studies published in Current Biology indicate that cyanobacteria utilize changes in pulse strength (amplitude) to communicate within individual cells. This research enhances our understanding of how biological rhythms synchronize to oversee cellular activities.
In the realm of AM (amplitude modulation) radio, a steady wave known as a carrier wave is produced by an oscillating electric current. The audio information—like music or speech—is layered onto this carrier wave by adjusting its amplitude in line with the audio signal’s frequency.
The research, led by Professor James Locke from Sainsbury Laboratory Cambridge University (SLCU) and Dr. Bruno Martins from the University of Warwick, discovered that a comparable AM radio-type mechanism operates in cyanobacteria.
For cyanobacteria, the process of cell division—which is when a single cell grows and splits into two—serves as the ‘carrier signal.’ The modulation comes from the bacteria’s internal 24-hour circadian clock, which keeps track of time.
This discovery addresses a long-held question in cell biology concerning how cells merge information from two cyclic processes—the cell cycle and the circadian rhythm—that function at distinct frequencies. Previously, it was a mystery how these two cycles could work in sync.
To crack this mystery, the research team utilized single-cell time-lapse microscopy alongside mathematical modeling. Through time-lapse microscopy, they monitored the expression of a protein called RpoD4, which is crucial for the initiation of transcription, the process by which genetic data from DNA is converted into RNA. The mathematical modeling enabled researchers to delve into the signal processing methods, comparing their findings with the microscopy results. They discovered that RpoD4 activates in pulses that coincide only with cell division, making it perfect for observation.
Dr. Chao Ye, the lead author, stated: “We found that the circadian clock influences the strength of these pulses over time. Using this method, cells can encode signals from two different oscillatory processes within a single output: the pulsing frequency indicates information about the cell cycle, while the pulsing strength reflects the 24-hour clock. This is the first instance where we’ve recorded a circadian clock using pulse amplitude modulation—a concept usually linked to communication technologies—to manage biological functions.”
“By altering the frequency of the cell cycle through environmental light or the circadian clock through genetic changes, we confirmed the underlying principles. It’s impressive to see natural examples of what we often regard as our own engineering concepts,” remarked co-corresponding author Dr. Martins. “Cyanobacteria have been around for 2.7 billion years and have elegantly solved this information processing challenge.”
Professor Locke added, “One reason we focus on cyanobacteria is that they feature the simplest circadian clock of all organisms. Understanding this provides the groundwork necessary to analyze clocks in more complex beings, including humans and crops.”
“These insights may have wider implications for synthetic biology and biotechnology. For instance, it could aid in creating crops that better withstand changing environmental conditions, which is vital for agriculture and sustainability.”
