Meet the Asgards: the microorganisms that might have begat us all

Hello Nature readers,
Today we explore the origins of all complex life, boggle at award-winning microscopy and learn that stomach bugs send protective immune cells rushing from gut to brain.

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‘Microproteins’ offer Alzheimer’s clues

More than 1,000 previously overlooked ‘microproteins’ have been found in samples of human brain tissue from people with and without Alzheimer’s disease. Dozens of the microproteins showed altered expression in people with Alzheimer’s disease, a finding that could pave the way for uncovering new mechanisms of ageing and neurodegeneration.

Infections send protectors from gut to brain

Immune cells that fight stomach bugs can migrate from the gut to the brain, where they establish a lasting ‘memory’ of previous infection, according to a study in mice. After an infection, gut-trained T cells journey to the meninges, a protective membrane that shields the brain. Once there, the cells become residents that can respond to later infections. The findings could shed light on how gut infections might affect neurological disorders, and could help to develop therapies that harness the relationship between the gut and the central nervous system.

This type of Arctic lake is going extinct

The loss of one of the last surviving epishelf lakes “marks the extinction of a rare feature of a colder world”, say researchers. These freshwater lakes form when an ice shelf blocks glacier meltwater from flowing into the salty Arctic sea. “It's really two unique ecosystems in the same water column, and you don't get that anywhere else,” says environmental fluid mechanics researcher Jérémie Bonneau, who co-authored a new study on the effects of the collapse of the Milne Ice Shelf on Ellesmere Island in Canada.

Meet the parents

Microorganisms from which all complex life might be descended — the Asgard archaea — were discovered in 2015 from DNA in sediments plucked from the bottom of the North Atlantic. Since then, researchers have been painstakingly culturing these exotic organisms and finding lots of surprises along the way.

There are no cities without countryside

“Urbanization is usually judged by what is built, but it should also be evaluated according to what it hollows out,” argue geographers Yansui Liu and Xinxin Huang. As people increasingly move to the city, those who remain in rural areas can start to lose their infrastructure and services — eroding these areas’ ability to fulfil essential roles, such as food production. “The onset of the urban age should not be misconstrued as a post-rural era,” the authors write. “The resilience of modern cities remains contingent on the integrity of the countryside.”

How to buckle up, lying down

Driverless cars can offer unusual seating arrangements and tempt passengers to recline or even to lie down — something seatbelts and airbags weren’t designed for. The rise of autonomous vehicles is encouraging the design of new types of crash-test dummies. And it might finally convince regulators to tackle outdated safety standards, says automotive safety engineer Becky Mueller. “It’s a good time to make sweeping changes.”