The week’s most astounding developments from the neobiological frontier.

October 28, 2021

Scare, learn, repeat

In a cruel world full of dangerous threats, fear is a powerful ally. Repeated exposure to scary cues conditions us for a cautionary prudence: Memories of dangerous things are physically captured in the brain through neuronal connections between “memory engram cells.” In a surprising twist, researchers at the Korea Advanced Institute of Science and Technology (KAIST) have discovered that repeated exposure to conditioned fears does not reinforce existing memories but rather weakens them—and forms new memories in nearby cells instead. When mice are conditioned with scary sounds and later re-exposed to them, their brains eliminate synaptic connections among the original memory cells and shift memory formation to new cells—something the researchers think is an adaptation allowing mammals to distinguish between similar but distinct scary events separated in time. Current Biology

How sleep states impact your metabolism

Scientists at ETH Zurich in Switzerland described a study this week in which they captured the breath of 13 people every 10 seconds throughout the night as they slept. All those exhalations passed through a powerful mass spectrometry instrument that teased apart expelled levels of ~2,000 trace molecules throughout the night. That allowed them to map metabolite levels with sleep stages and show how a number of major metabolic pathways are up- or down-regulated depending on whether someone is awake, in slow-wave sleep, or in REM sleep. So in addition to circadian clock genes exerting control of human metabolism throughout the night, sleep states may also be optimizing human metabolic circuits. Cell Reports

Harvesting drinking water from air could sustain a billion people

More than two billion people worldwide lack reliable access to clean drinking water, a state of affairs that causes major infectious disease outbreaks, drives malnutrition, and claims countless lives. One possible solution to this problem is using solar energy to harvest drinking water from air—an approach that offers the advantage of a remote, decentralized, off-grid supply. Researchers at the X Moonshot Factory, a subsidiary of Google’s parent company Alphabet, have analyzed the worldwide potential for atmospheric water harvesting based on the satellite data-driven Google Earth Engine platform, and they found that atmospheric water harvesting with a hypothetical small household device could provide safe drinking water for a billion people. Nature

Editor’s note: This post was updated on 10.30.21 to reflect X Moonshot Factory’s correct name and its corporate relationship with Google and Alphabet.

Mapping placebo pain modulation in the brain stem

Finding ways to safely address pain in all its acute and chronic forms is one of the most compelling unsolved problems of modern medicine. An emerging body of knowledge suggests future treatment strategies could exploit our brain’s natural placebo/nocebo mechanisms—though it’s complicated because these mechanisms are seated within tiny, hard-to-image brain stem networks. So researchers at the University of Sydney spent two days rubbing 25 people with creams deceptively labelled “lidocaine” (a painkiller), “capsaicin” (the active ingredient in chili peppers), and “Vaseline.” Then they applied the real substances while monitoring the subjects’ brain stem activity with a powerful MRI instrument, revealing the brain stem sites that likely influence how we experience pain. Journal of Neuroscience

What to do when we discover alien life

NASA astrobiologists are calling for a framework that would anticipate and avoid botched future reporting on extraterrestrial life by scientists and the media. Finding some future E.T. would be one of the most important discoveries in human history, but therein lies the danger. We are not likely to find something so definitive as little green men stepping off a flying saucer on the White House lawn. The first signs of aliens could be much more murky—like vague and inconclusive telescope spectra showing traces of biological chemicals far away in the Milky Way. How do we prevent the inevitable misreporting and over-hyped media circus? The scientists say we need objective standards of evidence for life, and they recommend developing a “confidence of life detection” (CoLD) scale. Nature

A VR view from inside the cell

New insight into the molecular life of the cell could be coming thanks to a novel, interactive 3D visualization tool developed at Lund University in Sweden. Called CellexalVR, the program imports single-cell RNA expression data and projects it into a virtual reality environment, allowing the user to stand inside a cell and experience it from different angles. As a bonus, because the tool was built on the Unity Engine gaming platform, CellexalVR has a multiplayer mode that allows several people to enter the same dataset remotely. iScience

Two mesoderm types during mouse organogenesis overlap in a UMAP when projected onto two dimensions.

Expanding the genetic code

Three chemists at Scripps Research Institute in La Jolla, CA, who penned a perspective this week on chemical synthesis and synthetic biology, are rewriting the central dogma of molecular biology by expanding the genetic code. Focusing on things like incorporating novel, non-canonical amino acids into proteins and cells for basic research and for new therapeutics, they also discuss introducing “unnatural” nucleotides beyond the familiar A-T-C-G and creating novel replication systems that can reproduce the unusual DNA using bioorthogonal chemistries. “These advances have allowed us to remove in a very significant way a billion-year constraint on the chemical nature of proteins imposed by the genetic code,” they write. Chem

Editor’s note: proto.life editorial director Jason Socrates Bardi worked at Scripps Research from 2000–2005.