Biology Professors' Research Appears in Science and Nature

IMAGING METHOD ELUCIDATES PROTEIN FUNCTION IN LIVING ANIMALS

“Watching life at the molecular level within a cell in an intact organism is really fascinating,” said UM biology professor Akira Chiba, and indeed his laboratory has developed a new way to do just that—in particular, with proteins. By creating “in vivo bioprobe imaging technology,” Chiba’s team has revealed activation patterns of proteins in the nervous system of fruit fly embryos. “It is the activation pattern of proteins, rather than their expression pattern, that provides important insights into their functions,” Chiba said. “But until now, it has been difficult to see when and where individual proteins are activated within live animals.”

Professor Akira Chiba and collaborators revealed activation pat- terns of proteins in the nervous systems of fruit flies that provide insight into their functions.

The discovery, made with UM senior scientist Daichi Kamiyama, is significant because researchers can now determine whether the activation patterns of various proteins cause illnesses or abnormalities. The new technology is based on previous advances in at least three fields: chemists have isolated genetically encoded fluorescent proteins that can render specific proteins visible in cells; physicists have demonstrated a phenomenon called FRET (Forster resonance energy transfer) that reveals conformational changes in proteins when they become activated; and biologists have devised sophisticated ways to deliver custom-designed molecular bioprobes to targeted cells in model organisms.

Chiba’s and Kamiyama’s research, published in the June 5, 2009, issue of Science, was funded by the National Institute of Neurological Disorders and Stroke and the National Institute of Mental Health.

ANCIENT TREE RINGS UNCOVER INTRIGUING CLUES TO THE EARTH’S CLIMATE

Leo Sternberg’s study of 45-million-year-old tree rings in fossilized forests of the far Canadian north has been highlighted in Nature. Trees have a great deal to teach us about the earth’s past climate, according to Sternberg, a biology professor at UM. “The more we know about that ancient climate, the more we can access the impact of greenhouse gases on present-day climate,” he said. “Climate regulation is a very complicated process with all types of feedbacks. The Eocene epoch—the time period of the tree fossils we studied—was exceptionally warm, but our knowledge of how energy was distributed throughout the earth during this epoch is very incomplete.”

Sternberg, an expert in plant physiology, conducted the research with colleague Hope Jahren of Johns Hopkins University. Examining carbon, oxygen, and hydrogen isotopes within the well-preserved rings, the scientists found unprecedented evidence of changes in the environment. Yet “there were some strange results from our analysis,” Sternberg said. “Although we know it was a very warm period, the isotopic composition at that site indicated a very cold environment. So how do we explain this anomaly? I would like to investigate it in more detail.”