At the largest winter monarch aggregation in central Mexico, scientists have observed that rodents attack monarchs that fall to the ground. For the first time, biologists working at Pismo State Beach, CA, discovered that the western harvest mouse also ate grounded monarchs. Documenting this new feeding behavior is a reminder of little we know about the interactions that may be lost as insect populations decline.

Researchers at Gladstone Institutes have fine-tuned an additional system for more efficient gene editing, using molecules called retrons. The group reported in the journal Nature Chemical Biology that retrons can be optimized for efficiency and used to edit genes in a variety of cell types, from fungi to human cells.

Johns Hopkins Medicine researchers have developed a color-coded test that quickly signals whether newly developed nanoparticles — ultra small compartments designed to ferry medicines, vaccines and other therapies — deliver their cargo into target cells. Historically, nanoparticles have a very low delivery rate to the cytosol, the inside compartment of cells, releasing only about 1%–2% of their contents. The new testing tool, engineered specifically to test nanoparticles, could advance the search for next-generation biological medicines. The technology builds upon nanoparticles currently used against cancer and eye disease, and in vaccines for viruses including SARS-CoV-2, the virus that causes COVID-19.

A reexamination of Earth's famous "whiff of oxygen" has the potential to rewrite early accounts of the planet's history by finding that atmospheric oxygen actually did not exist prior to the Great Oxygenation Event (GOE).