A human enzyme has changed little from its days as a bacterial enzyme, new research reveals. In fact, the enzyme appears to be unique in its ability to change its shape—and its job in cells—without overhauling its basic architecture.
Plastics and other polymers are used every day. These polymers are mostly made from fossil resources by refining petrochemicals. On the other hand, many microorganisms naturally synthesize polyesters known as polyhydroxyalkanoates (PHAs) as distinct granules inside cells.
Five million years ago, the Colorado River met the Gulf of California near the present-day desert town of Blythe, California. The evidence, say geologists, is in the sedimentary rocks exposed at the edges of the valley where the river flows today.
Air pollution impairs the function of blood vessels in the lungs, according to a study in more than 16,000 patients.