Life Sciences

Sleep remains one of the big mysteries in biology. All animals sleep, and people who are deprived of sleep suffer physically, emotionally and intellectually. But nobody knows how sleep restores the brain. Now, Giulio Tononi, a professor of psychiatry at the University of Wisconsin-Madison School of Medicine and Public Health, has discovered how to stimulate brain waves that characterize the deepest stage of sleep. The discovery could open a new window into the role of sleep in keeping humans healthy, happy and able to learn. The brain function in question, called slow wave activity, is…

Scientists at the Salk Institute for Biological Studies have identified an enzyme that pumps up a cell’s ability to maintain healthy muscle and restores normal muscle function in genetically engineered mice with weak muscles. The study, published online in Nature Medicine, is the first to explore the part this enzyme plays in a cascade of events triggered by exercise-induced hormones and other signals. In this particular pathway, a molecular switch turns on a set of muscle-specific genes in response to exercise by releasing a brake that normally keeps these genes off. Learning how this…

Dr. Yijun Qi (National Institute of Biological Sciences, China), reports his discovery of microRNAs in the unicellular green alga, Chlamydomonas reinhardtii. This is the first finding of microRNAs in a unicellular organism. “The finding changes the dogma that miRNAs only exist in multicellular organisms, and adds an important piece into the blooming small RNA world. A pressing question we have now is what these miRNAs are exactly doing in the green alga. I hope we will know the answers soon,” says Dr. Qi. MicroRNAs (miRNAs) are a class of conserved, approximately 21-nucleotide long RNAs that…

Hopkins researchers have identified a backup supply of stem cells that can repair the most severe damage to the nerves responsible for our sense of smell. These reservists normally lie around and do nothing, but when neighboring cells die, the scientists say, the stem cells jump into action. “These stem cells act like the Army Reserves of our nose,” explains lead author Randall Reed, Ph.D., a professor of neuroscience at Johns Hopkins, “supporting a class of active-duty stem cells that help repair normal wear and tear. They don’t come in until things are really bad.” The only nerve cells in…

Brains are able to adjust automatically to the demands of distinguishing between small differences in smell, new research at the University of Chicago shows. The research, which was conducted on rats, suggests that the human brain may be more adept at distinguishing smells than previously thought. The work comes from studies in the laboratory of Leslie Kay, Assistant Professor in Psychology at the University, who is looking at the ways animals perceive sensory stimuli by focusing on the neural basis of olfactory perception and how context and experience influence it. The research…

Findings described in a new study by Stanford scientists may be the first step toward a major revolution in human regenerative medicine—a future where advanced organ damage can be repaired by the body itself. In the May 2007 issue of The FASEB Journal, researchers show that a human evolutionary ancestor, the sea squirt, can correct abnormalities over a series of generations, suggesting that a similar regenerative process might be possible in people. "We hope the mechanisms underlying this phenomenon will ultimately lead to new insights regarding the potential of cells and tissues to be…

Oregon Health & Science University neuroscientists are eyeing a protein as a potential therapeutic target for multiple sclerosis because de-activating it protects nerve fibers from damage. OHSU researchers, working with colleagues at the Portland Veterans Affairs Medical Center and the University of Padova in Italy, have shown that genetically inactivating a protein called cyclophilin D can protect nerve fibers in a mouse model of multiple sclerosis. Cyclophin D is a key regulator of molecular processes in the nerve cell's powerhouse, the mitochondrion, and can participate in nerve fiber…

Marvin Chun of Yale University and colleagues have pinpointed brain regions critical to one of the brain’s more remarkable feats — piecing together a continuous view of the world by integrating snippets of visual input from constantly moving eyes. Since the eyeball has only a narrow field of clear view, it must continually make tiny shifts to sample the visual world. And during these shifts, which last thousandths of a second, people are essentially blind. The researchers’ experiments with human volunteers used an illusion known as “boundary extension” to establish brain regions involved…

Cells constantly swap cargo bound in vesicles, miniscule membrane-enclosed packages of proteins and other chemicals. Before the swap can take place, the vesicle membrane must fuse with another membrane, creating channels packages can pass through. This process, known as membrane fusion, is fundamental to health and disease. It occurs at fertilization and is particularly critical to keep hormones circulating and brain cells firing. Membrane fusion is also how HIV and other viruses infect cells. But membrane fusion occurs in less than a millisecond, making it difficult to see precisely how it…

Researchers have discovered how a defect in a single master gene disrupts the process by which several genes interact to create myelin, a fatty coating that covers nerve cells and increases the speed and reliability of their electrical signals. The discovery has implications for understanding disorders of myelin production. These disorders can affect the peripheral nervous system—the nerves outside the brain and spine. These disorders are known collectively as peripheral neuropathies. Peripheral neuropathies can result in numbness, weakness, pain, and impaired movement. They include one of…