Microbiology

Before the 18th century, scientists and non-scientists alike assumed that the material substance of living organisms was fundamentally different from that of non-living things -- organisms and their products were considered organic by definition, while non-living things were mineral or inorganic.  With the invention of chemistry in the late 18th century, scientists uncovered the incoherence of the traditional distinction: all material substances are constructed from the same set of chemical elements.  Today we understand that the special properties of living organic matter emerge…

After injury, even adult muscles can heal very well because they have a reserve supply of muscle stem cells, called satellite cells, which they can utilize for repair. Until now, it was unclear how this supply of satellite and muscle progenitor cells, out of which both muscle cells as well as satellite cells develop, keeps itself “fresh”. Developmental biologists Professor Carmen Birchmeier, Dr. Elena Vasyutina, and Diana Lenhard of the Max Delbrück Center for Molecular Medicine (MDC) Berlin-Buch, Germany, have now demonstrated that a molecular switch, abbreviated RBP-J, regulates this “…

A group of European researchers has developed a spinal cord model of the salamander and implemented it in a novel amphibious salamander-like robot. The robot changes its speed and gait in response to simple electrical signals, suggesting that the distributed neural system in the spinal cord holds the key to vertebrates’ complex locomotor capabilities. The EPFL Salamander Robot walks down to the waters of Lake Geneva. Credit: Photograph by A. Badertscher, courtesy Biologically Inspired Robotics Group, EPFL In a paper appearing in the March 9, 2007 issue of the journal Science, scientists…

Researchers at Texas A&M University are shedding light on a rare form of early blindness, identifying the cells involved and paving the way for possible therapies to treat or even prevent what is currently an incurable disease. The findings, funded by Fight for Sight and the National Institutes of Health, are published in the March 5-9 online Early Edition (EE) of the Proceedings of the National Academy of Sciences. Since his post-doctoral days at Harvard University, Texas A&M biologist Dr. Brian Perkins has been studying protein transport within photoreceptors—the rod and cone cells…

Antifreeze or “ice structuring” proteins – found in some fish, insects, plants, fungi and bacteria – attach to the surface of ice crystals to inhibit their growth and keep the host organism from freezing to death. Scientists have been puzzled, however, about why some ice structuring proteins, such as those found in the spruce budworm, are more active than others. Fluorescence microscopy now has shown how those aggressive proteins protect the cells of the insect, which is native to U.S. and Canadian forests. Ice crystals decorated by fluorescent antifreeze proteins. Credit: Ido Braslavsky/…

Scientists have identified a molecular switch that causes the differentiation of neurons in the cerebellum, a part of the brain that helps to regulate motor functions. A study published this week in the scientific journal PNAS provides new information on the origin of different cells in the cerebellum, an important component of the central nervous system found in all vertebrates, including humans, and the part of the brain that controls movement. The study was completed by researchers from the Institute for Research in Biomedicine (IRB Barcelona), the Department of Cell Biology of the…

For a lucky subset of vertebrates, losing an appendage is no big deal. As many an inquisitive child knows, salamanders can regenerate lost limbs or tails; and as lab investigators know, zebrafish can regrow lost fins. Of course, humans and other "higher" vertebrates must make do with repairing rather than regenerating damaged tissues. Though whole body generation (WBR) does occur, it’s typically restricted to a subset of morphologically less complex invertebrates, such as sponges, flatworms, and jellyfish. In a new study, Yuval Rinkevich et al. discovered an unusual mode of WBR in our…

Researchers at Yale have identified multiple pathogenic "alien islands" in the genome of the A. baumannii, bacteria that has been responsible for new and highly drug-resistant infections in combat troops in the Middle East, according to a report in the March 1 issue of Genes and Development. "Drug resistant bacterial infections are a rapidly growing problem in hospital settings, and now in difficult conditions of combat. We targeted A. baumannii as a growing threat for our troops in Iraq," said s principal investigator Michael Snyder, the Lewis B Cullman Professor of Molecular Cellular…

Among the central mysteries of neurobiology is what properties of the young brain enable it to so adeptly wire itself to adapt to experience—a quality known as plasticity. The extraordinary plasticity of the young brain occurs only during a narrow window of time known as the critical period. For example, children deprived of normal visual stimulation during an early critical period of the first few years of life suffer the permanent visual impairment of amblyopia. Now, researchers comparing the genetic machinery of juvenile and adult mouse brains undergoing visual experience have uncovered…

Using a state-of-the-art technique to map neurons in the spinal cord of a larval zebrafish, Cornell University scientists have found a surprising pattern of activity that regulates the speed of the fish’s movement. The research may have long-term implications for treating injured human spinal cords and Parkinson’s disease, where movements slow down and become erratic. The study, "A Topographic Map of Recruitment in Spinal Cord," published in the March 1 issue of the journal Nature, maps how neurons in the bottom of the fish’s spinal cord become active during slow movements, while cells…