Science in Brief

UCSF Researchers Identify Possible Adult Obesity Factor

Researchers at UCSF have pinpointed a physiological process which they believe may contribute to obesity in middle-aged people.

In their study, researchers found that middle-aged mice expended fewer calories carrying out the same activities as younger mice, a process that they suspect happens in humans as well.

The researchers discovered that the only real difference between the younger and middle-aged mice lay in the increased efficiency of energy use in the older mice.

The evidence that middle-aged mice burned fewer calories per dash across their cages implied that aging people may burn less calories in their activities.

"This could mean that I'd burn less energy today running an 8-minute mile at a given weight than I would have 20 years ago," said UCSF psychiatry professor Laurence Tecott, the lead author of the study, in a statement.

The most dramatic results in the study were obtained using mice genetically engineered to lack a brain cell receptor involved with receiving signals from serotonin, a brain chemical.

Tecott said that the receptor may regulate endocrine function and nervous system activity.

In such a case, a drug that stimulated the serotonin receptor might decrease the energy efficiency of physical activity, allowing more calories to be burned.

Tecott said that further studies could potentially more fully explain why some mammals, such as humans, have a tendency to get heavier as they get older.

'Periodic Table' of Proteins Unveiled

Researchers at UC Berkeley and Lawrence Berkeley National Laboratory have created a "periodic table" of the protein building blocks used to construct the complex proteins that make up life on the planet.

The researchers' map shows the similarities and differences between the 500 most common protein building blocks that compose about 80 percent of all known protein structures.

The table may potentially help scientists understand the relationships among proteins in nature the same way chemists are able to draw relationships between molecules using the periodic table of the elements.

"This is a very good way to organize and visualize the whole protein universe," said Sung-Hou Kim, a UC Berkeley chemistry professor and head of the Structural Biology Department at Lawrence Berkeley lab.

The map offered potential for numerous areas of biological and biomedical research, including the design of drugs with fewer negative side-effects, Kim said.

Kim, along with UC Berkeley graduate students Jingtong Hou and Gregory Sims, and research associate Chao Zhang, published their map this week in the online early edition of the Proceedings of the National Academy of Sciences.

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