Scientists have isolated a unique molecular pattern that might one day enable a 'stress vaccine' to exist for real – and they found it hidden inside a bacterium that thrives in dirt.

Mycobacterium vaccae is a non-pathogenic bacterium that lives in soil, and has shown considerable promise in health research; now, a new study may have finally figured out why.

The findings suggest that a specific kind of fat inside M. vaccae could be why exposure to this seemingly beneficial bacterium in ground soil may be good for us.

This work ties in with the idea of "old friends", a hypothesis that claims humans co-evolved with a bunch of useful microorganisms, and losing those ties in the modern environment has led to an increase in allergic and autoimmune diseases.


"The idea is that as humans have moved away from farms and an agricultural or hunter-gatherer existence into cities, we have lost contact with organisms that served to regulate our immune system and suppress inappropriate inflammation," says neuroendocrinologist Christopher Lowry.
神经内分泌学家Christopher Lowry说:“这个说法就是随着人类从农场和以农业或狩猎采集为生的生活转移到了城市中,我们失去了和微生物的联系,而这些微生物能调节免疫系统、抑制不良炎症。”

"That has put us at higher risk for inflammatory disease and stress-related psychiatric disorders."

Lowry has been researching M. vaccae for years, finding in a previous study that injecting mice with a heat-killed preparation of the bacterium prevented the emergence of stress-induced reactions in the animals.

But until now, nobody was sure what was it in M. vaccae that could be responsible for such effects.