Scientists gave worms magnetic bacteria and they lived 43% longer

Worms fed a diet supplemented with a magnetic soil bacterium lived an average of 43.39% longer, just over 43%, than untreated worms, according to a study led by Prof. An Xu at the Hefei Institutes of Physical Science, part of the Chinese Academy of Sciences. The effect showed up only when the bacteria retained their magnet-making machinery, not in engineered strains stripped of it. The animals in the study were Caenorhabditis elegans, the millimeter-long roundworm long used as a stand-in for testing aging biology in the laboratory. Researchers have previously pushed the same species past its normal lifespan using dietary restriction or mutations in insulin-like growth-factor signaling, but a bacterium’s own magnetic hardware driving a comparable gain has no clear precedent in the published record.

A Gain Tied to One Bacterial Trait

The bacterium behind the effect, Magnetospirillum magneticum AMB-1, builds internal magnetic compasses called magnetosomes, chains of iron-mineral crystals that let the microbe orient itself along Earth’s magnetic field to find the oxygen levels it prefers. Xu’s team compared wild-type AMB-1 against two engineered variants stripped of that trait: one that could reversibly lose its magnetism and one that could not produce magnetosomes at all. Only the wild-type, magnetosome-producing bacteria extended lifespan in the worms that ate them; the strain with no magnetosome production at all delivered no longevity benefit whatsoever, a result that pins the effect on the bacteria’s magnetic hardware rather than on some other, incidental byproduct of the microbe’s metabolism.

The paper, titled “A novel role for magnetotactic bacterium: Magnetospirillum magneticum AMB-1 prolonged healthy lifespan of Caenorhabditis elegans via regulating ferroptosis,” appeared in the journal Free Radical Biology and Medicine. Wild-type bacteria able to produce functioning magnetosomes were the only version tested that moved the survival curve at all, according to the study.

Ferroptosis, the Iron-Driven Death the Bacteria Blocked

The mechanism the team traces runs through ferroptosis, a form of cell death driven by iron buildup and the accumulation of lipid peroxides in cell membranes, distinct from the more familiar programmed-death pathways cells also use. Aging C. elegans normally accumulate iron and lipid-peroxidation damage as they get older, and worms carrying the magnetotactic bacteria showed reduced iron accumulation and decreased lipid peroxidation, effectively suppressing the ferroptosis that would otherwise speed tissue decline. The researchers tied the shift to three specific genes, ftn-1, bli-3 and ads-1, all involved in iron handling or oxidative-stress response, whose activity changed in worms that carried the bacteria compared with worms that did not. Iron accumulation and lipid-peroxidation damage are not unique to nematodes; both have been documented in aging human tissue as well, including the brain, which is part of why a pathway that visibly reverses the pattern in a simple animal draws attention from researchers who study aging in mammals.

Worms carrying wild-type AMB-1 also kept more of their neurological function and intestinal integrity intact into old age than untreated worms did, a secondary finding the team reports alongside the main longevity figure, and one that suggests the bacteria were slowing tissue-level decline rather than simply extending a worm’s final, frail days.

From a Soil Microbe to Human Aging Research

C. elegans has anchored aging research for decades because its transparent, millimeter-long body and roughly three-week lifespan let scientists test an intervention and see the result in weeks rather than years. A related, older discovery in the same species, that blocking insulin-like growth factor signaling can triple its adult lifespan, has shaped how researchers think about longevity pathways across far more complex animals, which is part of why a 43% gain in a worm gets attention well beyond nematode biology.

Whether magnetotactic bacteria or their magnetosomes could deliver any comparable benefit in mice, let alone in people, remains untested, and Xu’s team frames the finding as a mechanism worth pursuing rather than as a treatment anyone should attempt to replicate. Soil-dwelling magnetotactic bacteria are not part of any normal human or mammalian diet, and the study offers no evidence about what exposure to them would do outside a nematode’s gut. A worm’s intestine, immune system and lifespan-regulating pathways differ enough from a mammal’s that a finding of this size routinely shrinks, or disappears entirely, by the time it is tested further up the chain of model organisms, a pattern that has played out with plenty of other single-species longevity results before this one.

The magnetosome connection nonetheless narrows the search considerably. Rather than screening broadly for any gut microbe that might extend lifespan, Xu’s group now has a specific, testable hypothesis: it is the iron-mineral structure itself, not some unrelated metabolic quirk of Magnetospirillum magneticum, driving the benefit, and that structure can be produced, purified and dosed independently of the living bacterium in future experiments.

For now, the result belongs to a population of worms in a Hefei laboratory: an average lifespan extension of 43.39%, just over 43%, recorded in animals that received a bacterium whose only previously known trick was finding north.

This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.

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