Bathed in nutrients, but in the absence of any particular cue, axons will extend from cortex nerve cells in all directions (top image). Toss in a growth stimulator like semaphorin-7a, and axon growth is heavier nearest the cue (bottom image). Credit: Johns Hopkins Medical Institutions, Nature.
For decades, scientists have hunted for signals that guide nerve cells’ tentacle-like axons, hoping to understand how these cell tips reach out to distant targets. It’s knowledge that might one day help researchers learn how to rebuild nerves lost to spinal cord injuries or diseases like Huntington’s.
Now, a Johns Hopkins team studying a family of proteins best known for repelling axons and inhibiting their growth reports finding one member that unexpectedly promotes axon growth instead. In their experiments, rat nerves in the lab grew more and longer axons on the side nearest a source of this protein, called semaphorin-7a. Moreover, in mice without semaphorin-7a, axons of some odor-sensing nerve cells never reached their targets, the scientists report in the July 24 issue of Nature.
"I’ve been studying semaphorins for about a decade and didn’t expect to find any that stimulated axon growth, certainly not to the extent we saw in the lab and in mice," says Alex Kolodkin, Ph.D., professor of neuroscience in The Johns Hopkins University School of Medicine’s Institute for Basic Biomedical Sciences. "Now we need to figure out how semaphorins balance their repulsive and attractive effects."
Polymers Based on Boron?
18.01.2018 | Julius-Maximilians-Universität Würzburg
Bioengineered soft microfibers improve T-cell production
18.01.2018 | Columbia University School of Engineering and Applied Science
What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...
For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.
Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...
At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.
No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...
Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.
Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...
The oceans are the largest global heat reservoir. As a result of man-made global warming, the temperature in the global climate system increases; around 90% of...
08.01.2018 | Event News
11.12.2017 | Event News
08.12.2017 | Event News
18.01.2018 | Life Sciences
18.01.2018 | Life Sciences
18.01.2018 | Earth Sciences