In two studies of mice, a molecule called leukotriene helped trigger food-induced anaphylaxis. A drug approved for asthma — zileuton — diminished it.

Alpha Centauri A, four light-years from Earth, may host a gas giant. If confirmed, no Earthlike planets orbit in the star’s habitable zone.

Researchers reconstructed a roughly 2,000-year-old woman’s tattoos, from prowling tigers to a fantastical griffinlike creature.