ScienceAdviser (AAAS)

A research team recently described large extracellular vesicles shed by astrocytes grown in lab dishes. The oddities contain intact mitochondria and other cellular features and can move like cells for a period but don’t have a gene-filled nucleus to govern their behavior. Neurobiologist Anna Erlandsson recalled first seeing these strange structures a decade ago. “ We didn’t even have a name for them because we haven’t seen anything like that before … For some years they were just odd features,” Erlandsson recalled. But that changed when Abdulkhalek Dakhel joined her lab. To finally assign them a name, Erlandsson, Dakhel, and colleagues mashed together “zombie” and “ectosomes” (a generic name for extracellular vesicles that bud off from a cell surface) to get “zombosomes.”

The team also found clumps of alpha-synuclein in the blobs, similar to the protein clumps seen in Parkinson’s disease; the group suggests zombosomes may contribute to the disease’s pathology—although probing that hypothesis will require additional research.

The team scanned the genomes of 112 species, seeking changes in the DNA that makes ghrelin, dubbed the “hunger hormone ” because it was once thought to be the key to obesity in humans. In snakes, chameleons, and toadhead agamas, ghrelin genes were either missing or so warped by mutations they could no longer encode the hormone, the scientists found. When the researchers looked at MBOAT4, an enzyme that makes ghrelin function, they found that it too was lost in snakes, chameleons, and the agamas.

Losing ghrelin and MBOAT4 may have been part of how these ambush predators adapted to a boom-and-bust feeding schedule. Normally, ghrelin can help the body turn fat into energy when food is scarce. Without ghrelin and MBOAT4, the reptiles may be able to hold onto their energy reserves for longer, letting them persist in low power mode for months to a year between meals.

Understanding how these reptiles’ bodies process food and fat without ghrelin might help us better understand how the hormone works in other species , like humans, said genomicist Todd Castoe, who was not involved with the study. Though the applications to people are still unclear, he noted that it was basic research decades ago on another reptile—the gila monster—that eventually led to the development of GLP-1 drugs. “You never know where things are going to go.”

“[Freezing rain] does not happen every day in the winter,” earth systems scientist Zong-Liang Yang told ScienceAdviser. “But once it happens, it’s disastrous.”

To form, freezing rain requires a cold-warm-cold atmospheric sandwich: high, cold air yields snow, which melts to rain as it falls, then gets cold-shocked near the ground; it freezes on contact into characteristically “sticky” ice. To analyze freezing rain patterns over time, Yang and his postdoctoral student compiled more than 54,000 county-level reports of freezing rain from a National Oceanic and Atmospheric Administration (NOAA) database covering 1996 to 2025. They saw that the precipitation had shifted south over time, to a band from eastern Texas to western Pennsylvania. The highest frequency of freezing rain events also moved from December to February.

While it’s too early to say if climate change is playing a role, global warming does make the warm “meat” layer of the atmospheric sandwich more prevalent. If, as predicted, climate change begins to shift global wind circulation and bring low, cold air south from the Arctic, researchers think the Goldilocks conditions behind freezing rain could get all too common.

With contributions from John Travis, David Grimm, and Hannah Richter

Do you have a burning science question you can’t seem to find a good answer for? Submit it to Ask Science! Selected questions will receive responses from Science editors right here in ScienceAdviser.

Want more? Catch up on past issues of ScienceAdviser.

If you were forwarded this newsletter by a friend, you can subscribe for free here.