Now, one of the freshly minted Nobel laureates has debuted a new method to make abundant, long-lasting Tregs. In the first of two papers in this week’s Science Translational Medicine, immunologist Shimon Sakaguchi and colleagues describe how their lab-generated Tregs effectively suppress immune responses in mice. In the second, he and other researchers made Tregs to treat a specific autoimmune skin disorder in mice. Setting the stage for a clinical trial, they used a similar method to generate human Tregs from the blood of people with the painful condition.

“These are going to be very important studies to help catapult the field forward,” said immunologist Qizhi Tang, who was not involved in the work.

The idea provides an elegant answer to what the study’s lead author, Reed Goodman, calls a chicken-and-egg conundrum surrounding the birth of ancient Sumerian society: “How are you getting so many people living together before you have the governments necessary to operate full-fledged irrigation systems?”

Goodman extracted a soil core from below the surface of the Sumerian urban center Lagash, which sits near the modern-day Iraqi city of Nasiriyah, almost 200 kilometers from the coast. But the core sample revealed that some 7000 years ago, this city abutted the coast. Twice-daily tides in the Persian Gulf would have pushed saltwater up the Tigris and Euphrates, forcing freshwater back the way it came and making it available for farmers to water wheat fields, date palm groves, and vegetable gardens.

“This is confirming the foundation of the earliest known civilization wasn’t the kind of irrigation we usually think of,” says archaeologist Jennifer Pournelle, who wasn’t involved with the new research. “It wasn’t making a desert bloom; it was tidal irrigation in a delta.”

To better understand Mayan eclipse timekeeping, a pair of researchers reanalyzed tables in the oldest surviving book written in the Americas, called the Dresden Codex. They ran the calculations of different possible systems for tracking solar eclipses with specific numbers of days, months, and years, and reconstructed when real eclipses would have occurred in each.

The researchers determined that, contrary to previous understanding, the Mayan timekeeping method doesn’t restart at the end of the table (405 months), but at the table’s 358th month. Every once in a while, the table would need to be restarted at the 223rd month to account for built-up deviations, sort of like our modern Leap Year procedure. The method keeps the table accurate at predicting eclipses, with only 51 minutes of deviation over 134 years.

While researchers may never know for sure why the Mayans decided to keep time this way, they can be sure the system was spot-on; it predicted a solar eclipse to within a day as recently as 1991.

The microscopic “flowers” Freeman and her colleagues made grow naturally during the DNA-making process, thanks to an enzyme that can synthesize DNA without a template. This enzyme also creates long sections that change shape with acidity. “Depending on the length of these segments, and where they are within the petals, they fold and act like tiny springs, driving flowers to close, open, shrink, or swell,” said Freeman.

In experiments, the team showed that they could induce flower opening or closing in a matter of seconds. Indeed, they were able to code a hidden message in the flowers that’s only visible when the pH is lowered to 5. And they could pack the crystals with enzymes that are only released when the flower opens its petals. These abilities demonstrate the potential for using these flowers as targeted drug delivery devices.

“Imagine a future where ingesting smart capsules triggers the precise release of medication upon detecting a disease, only to deactivate once the ailment is cured,” she said.

With contributions from John Travis, Michael Price, and Hannah Richter

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