Researcher decodes molecular process that controls nerve cell growth

In order to be able to receive signals from other cells, nerve cells form complex extensions called dendrites (from the Greek ‘dendron’ meaning tree). The growth of dendrites in the human brain takes place mainly during late embryonic and infantile brain development. During this phase, dendrites, with a total length of many hundred kilometres, grow from the 100 billion nerve cells in our brain. The result is a highly-complex network of nerve cells that controls all bodily functions – from breathing to complicated learning processes.

In order that this incredible growth phase of brain development does not lead to chaos, the growth of the dendrites must be accurately controlled. In fact, a large number of signal processes control the direction and the speed of dendrite growth by influencing the structure of the cytoskeleton, which is inside the growing dendrite and responsible for its shape and extension.

The Göttingen-based brain researcher Hiroshi Kawabe has now discovered exactly how the growth of the cytoskeleton is controlled during the dendrite development. Using specially bred genetically engineered mice, the Japanese guest scientist, who conducts research at the Max Planck Institute for Experimental Medicine, discovered that the Nedd4-1 enzyme is essential for regular dendrite growth. Nedd4-1 is an enzyme that usually controls the degradation of protein components in cells by combining them with another protein called ubiquitin. The cell identifies these ubiquitinated molecules as “waste” and degrades them. In some cases, however, the ubiquitination does not lead to the degradation of the marked protein but changes its function instead.

Nedd4-1 prevents degradation of the cytoskeleton

Hiroshi Kawabe has now shown that the Nedd4-1 enzyme ubiquitinates a signal protein called Rap2, and thus prevents it causing the dismemberment of the cytoskeleton and the collapse of the dendrites. “As long as Nedd4-1 is active, the nerve cell dendrites can grow normally,” reports Kawabe. “In its absence, the dendrite growth comes to a standstill and previously formed dendrites collapse, with dramatic consequences for the function of nerve cell networks in the brain.”

via Max Planck Society – Press Release.

U.S. military mission in Iraq to get a new name: Operation New Dawn

The U.S. military mission in Iraq will soon be getting a new name.

As of Sept. 1, Operation Iraqi Freedom becomes Operation New Dawn.

Defense Secretary Robert Gates said in a memo Wednesday that the name change – which is to immediately follow the scheduled withdrawal of U.S. combat troops from Iraq – will send a strong signal that American forces have a new mission. He also said it reinforces the U.S. commitment to honor its security agreement with Iraq and recognizes “our evolving relationship” with the government there.

ABC News first reported on the memo Thursday evening.

via Tulsa World: AP Stories.

Not sure how this slipped by Pentagon security, but I’ve found the “core rule set for operation new dawn (pdf)“. Velocity reducers will not be allowed, but overall there is a great emphasis on safety and sportsmanship.   With rules like these, war will be much better. The most important rule is now to have fun.