Microbiology

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.

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 further up the spinal cord activate as movements speed up.

To function, each living cell needs both to build new and to degrade old or damaged proteins. To accomplish that, a number of intracellular systems work in concert to keep the cell healthy and from clogging up with damaged proteins. When proteins or peptides mutate, they can present major problems to the clearing up of the intracellular environment. In Huntington's disease (HD) the disease provoking mutation in the huntingtin gene eventually causes the cell to build up intranuclear and cellular inclusions of protein-aggregates, made up primarily of huntingtin.

An artificial nose could be a real benefit at times: this kind of biosensor could sniff out poisons, explosives or drugs, for instance. Researchers at the Max Planck Institute for Polymer Research and the Max Planck Institute of Biochemistry recently revealed a technique for integrating membrane proteins into artificial structures.

Membrane proteins have several important functions in the cell, one of which is to act as receptors, passing on signals from molecules in the air, for example, to the cell interior. They are thus ideal biosensors, but until now were difficult to access in the lab.

Human nerve stem cells transplanted into rats' damaged spinal cords have survived, grown and in some cases connected with the rats' own spinal cord cells in a Johns Hopkins laboratory, overturning the long-held notion that spinal cords won't allow nerve repair.

A report on the experiments will be published online this week at PLoS Medicine and "establishes a new doctrine for regenerative neuroscience," says Vassilis Koliatsos, M.D., associate professor of neuropathology at Johns Hopkins.

During development and during pathological processes in the adult, cells are constantly changing their function. One, well-characterized, cellular transition that occurs during development, as well as during wound healing, tissue fibrosis, and tumor metastasis, is the transition from an epithelial cell to a mesenchymal cell (often a fibroblast).

This change in cell type and function is known as epithelial-mesenchymal transition (EMT) and it has been shown that a protein known as FSP1 is important for this transition.

Thanks to Buck and Axel and colleagues, most neuroscientists are aware of the precise topographical map of the mouse olfactory nerve projection in which each olfactory sensory neuron (OSN) expresses a single odorant receptor (OR), and OSNs expressing a given OR converge on a set of glomeruli in the olfactory bulb. This week, Sato et al. mapped the zebrafish axonal projection using a bacterial artificial chromosome transgene. The transgene contained a cluster of 16 OR genes, two of which (OR111–7 and OR103–1) were replaced with yellow and cyan membrane-targeted reporters. Distinct sets of OSNs were fluorescently labeled, whereas their axons targeted the same cluster of glomeruli.

A breakthrough in understanding the way atoms move across cell membranes in the human body could pave the way for the development of new treatments for inflammatory diseases such as rheumatoid arthritis.

Scientists at the University of Leeds have identified a previously unknown natural mechanism that opens ion channels – proteins at the cell surface that act as doorways into and out of cells – through the naturally occurring protein thioredoxin.

Ion channels allow movement of ions - electrically charged atoms - across the cell membrane to carry out various functions such as pain transmission, timing of the heart beat, and regulation of blood glucose.