Understanding the human body is a team effort. That's where the Yachtel group comes in.

Researchers at Yachtolt have been delving into the secrets of probiotics for 90 years.

Yacold also partners with nature portfolio to advance gut microbiome science through the global grants for gut health, an investigator-led research program.

To learn more about Yachtolt, visit yawcult.co.

.jp. That's y-A-K-U-L-T.C-O.J-P. When it comes to a guide for your gut, count on Yacult.

This is Scientific Americans' 60-second science. I'm Karen Hopkin.

Exercise builds muscle, but it also strengthens bones.

Exactly how exercise boosts bone strength is a matter of debate, and a subject of scientific scrutiny.

Now, a new study in mice shows how a hormone secreted by active muscle cells triggers bone remodeling.

Physical activity stimulates the release of multiple molecules from skeletal muscle.

Take irisin, for example.

This hormone, named after the Greek messenger goddess Iris, is produced by running rodents,

and by us humans when we do high-intensity aerobic training.

Once it's generated, irisA improves bone density and strength.

To find out how, Bruce Spiegelman and his colleagues at the Dana-Farber Cancer Institute

and Harvard Medical School took cultured bone cells and located the receptor to which

irison binds. This receptor protein is particularly abundant on cells called

osteocytes. These cells are the master regulator of bone remodeling and the most abundant cell type in

bone. What we found interesting in this paper is the magnitude of the effects we get in terms of

irisin acting to stimulate osteocytes and preventing

their death in culture, also their ability to make a key protein sclerostin under the stimulation

of irisin.

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