Proceedings of the National Academy of Sciences · 27 July 2026 · From issue 12

Free-living bacteria, not plant partners, were the first to fix nitrogen from the air.

Lu Ling, Sishuo Wang et al., The free-living wellspring of symbiotic nitrogen fixation in Bradyrhizobium, Proceedings of the National Academy of Sciences.

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Also in issue 12 15 papers

In mice, an antibody treatment for tumors fails without a working internal immune sensor.
Nature Communications
Warming is releasing trapped mercury, making Antarctic waters a growing mercury hotspot.
Proceedings of the National Academy of Sciences
In spotted hyenas, inherited social rank made females more unequal in reproductive success than males.
Science Advances
A new blood test method found over 1,200 new gene-protein links in South Asian volunteers.
Nature Genetics
Mercury has its own belt of trapped, energetic electrons that can survive for days.
Nature Astronomy
In lab-grown cell sheets, stretching makes fiber networks clump and squeeze the nucleus out of its cage.
Nature Physics
Invasive species do more damage in poorer nations, not richer ones as long assumed.
Science
Muscle and exercise changes in long COVID and chronic fatigue patients do not match those caused by lying in bed for weeks.
Nature Communications
Ancient flooded river valleys left hidden salty groundwater under more than 10,000 square kilometers of coastal Louisiana.
Nature Communications
In monkeys, two separate brain systems adjust on their own to help flexible decisions, without depending on each other.
eLife
Most carbon from Canada's record 2023 wildfires rose from soil, not burning trees.
Geophysical Research Letters
In computer simulations, uneven water spacing pushed a wet proton between two known shapes.
Nature Chemistry
In lab tests, recycled plastic cracked sooner and failed faster than new plastic under stress and chemicals.
Science Advances
Industrial chicken farming raised chicken-to-wild-bird germ jumps by about 100-fold since 1900.
Proceedings of the National Academy of Sciences

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