Bacteria Engineered With Synthetic Circadian Clocks

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Many of the body’s processes follow a natural daily rhythm or so-called circadian clock, so there are certain times of the day when a person is most alert, when the heart is most efficient, and when the body prefers sleep. Even bacteria have a circadian clock, and in a December 10 Cell Reports study, researchers designed synthetic microbes to learn what drives this clock and how it might be manipulated.

“The answer seems to be especially simple: the clock proteins sense the metabolic activity in the cell,” says senior author Dr. Michael Rust, of the University of Chicago’s Institute for Genomics and Systems Biology.

“This is probably because cyanobacteria are naturally photosynthetic–they’re actually responsible for a large fraction of the photosynthesis in the ocean–and so whether the cell is energized or not is a good indication of whether it’s day or night,” he says. For photosynthetic bacteria, every night is a period of starvation, and it is likely that the circadian clock helps them grow during the day in order to prepare for nightfall.

Dr. Michael Rust
Dr. Michael Rust

To make their discovery, Rust and his colleagues had to separate metabolism from light exposure, and they did this by using a synthetic biology approach to make photosynthetic bacteria capable of living on sugar rather than sunlight.

“I was surprised that this actually worked–by genetically engineering just one sugar transporter, it was possible to give these bacteria a completely different lifestyle than the one they have had for hundreds of millions of years,” Rust says. The findings indicate that the cyanobacteria’s clock can synchronize to metabolism outside of the context of photosynthesis. “This suggests that in the future this system could be installed in microbes of our own design to carry out scheduled tasks,” he says.

In a related analogy, engineers who developed electrical circuits found that synchronizing each step of a computation to an internal clock made increasingly complicated tasks possible, ultimately leading to the computers we have today. “Perhaps in the future we’ll be able to use synthetic clocks in engineered microbes in a similar way,” Rust says.

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Other researchers have shown that molecules involved in the mammalian circadian clock are also sensitive to metabolism, but our metabolism is not so closely tied to daylight as the cyanobacteria’s. Therefore, our bodies’ clocks evolved to also sense light and dark.

“This is presumably why, in mammals, there are specialized networks of neurons that receive light input from the retina and send timing signals to the rest of the body,” Rust explains. “So, for us it’s clearly a mixture of metabolic cues and light exposure that are important.”

The bacteria that live inside of our guts, however, most likely face similar daily challenges as those experienced by cyanobacteria because we give them food during the day when we eat but not during the night. “It’s still an open question whether the bacteria that live inside us have ways of keeping track of time,” Rust says.

The report, “Controlling the Cyanobacterial Clock by Synthetically Rewiring Metabolism,” was published in Cell Reports.

By Kevin Jiang

Possible new law of nature on the way

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The world of physics is excited about strong but early evidence about the behavior of muons, paricles identical to electrons only 200x more massive (heavier), which once born take 2.2 microseconds to decay into an electron, and which spin like tops. In a new, extremely precise measurement, they were made to wobble using magnetic fields but they unexpectedly wobbled quite significantly faster than the Standard Model suggests they would. They might spin so fast due to an unknown force caused by an unknown particle, and this is what is so exciting.

“We found that a muon … is not in agreement with our current best theory of physics at the subatomic level, and … it potentially points to a future with new laws, new particles and new forces in physics which we haven’t seen to date,” said Professor Mark Lancaster at U of Manchester.

“The main goal of the experiment is to make the measurement and compare with the theory, and if they disagree then it’s telling us that there’s something in nature which is not in the theory,” explained James Mott at Fermilab.

The four known forces of nature (gravity, electricity, two nuclear forces: strong and weak interactions) have left scientists without an answer for some observed phenomena, such as the speed at which galaxies spin (faster than the best model suggests). Therefore, they continue to search for glitches in their already-tight models which might point them things they don’t yet know about.

The most recent work was done at Fermilab (Muon g-2 experiment), but a similar experiment was already done earlier at the Large Hadron Collider. These tools accelerate particles in large rings at close to the speed of light.

The evidence needs more tests for greater certainty, particularly to rule out the possibility of a systematic error, and particularly with a new, independent experiment, but physicists will be chasing this line of experiment eagerly.

“This is outstanding confirmation of experimental technique, and very, very suggestive of the possibility of new physics,” noted scientist David Hertzon of U of Washington.

By the editors

#AnomalousMagneticDipoleMomentOfTheMuon #QuantumElectrodynamics

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People in Kachin state demonstrate against China

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YANGON, Myanmar – The people in the Pharkant area of Kachin state demonstrated against China this week, drawing a cross on the Chinese flag and burning a picture of Myanmar’s military leader Min Aung Hlaing.

“China stands with the military leader,” shouted the demonstrators.

By Htay Win
Photo credit Aye Yarwaddy

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Myanmar military council arrests the artist Zarganar

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YANGON, Myanmar – The artist Zarganar was arrested by the Myanmar military council from his home in Tarmwe township, Yangon this morning.

Zarganar is not only a director but also a comedian famous for political jokes since the 1988 democratic revolution.

Zarganar was arrested by the Myanmar military many times before 2010.

By Htay Win
Photo credit Zarganar page

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Kayin IDPs struggle to get for food

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YANGON, Myanmar – Kayin internally displaced people are desperate for food, clothing and shelter, hiding in the forest from the air strikes of the Myanmar military.

The IDPs fled to neighboring Thailand, but Thai government turned them back. However, Wednesday morning the Thai government opened Maeseli jetty in Maehaungsaung district to sending rations and medicines over the border to Kayin state, according to a Thai media.

By Htay Win

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Twenty Myanmar celebrities charged with incitement

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YANGON, Myanmar -They were charged under the country’s media law with inciting government employees to join the popular civil disobedience movement (CDM) through social media.

Celebrities took part in the NLD election campaigns and are thought to have played a large part in influencing the public, particularly Myanmar’s youth, to vote for Aung San Suu Kyi.

By Htay Win
Photo credit Myanmar celebrity

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