To understand where fat comes from, you have to start with a skinny mouse. By using such a creature, and observing the growth of fat after injections of different kinds of immature cells, scientists at the Howard Hughes Medical Institute and Rockefeller University have discovered an important fat precursor cell that may in time explain how changes in the numbers of fat cells might increase and lead to obesity. The finding, published online in this week's issue of the journal Cell, could also have implications for understanding how fat cells affect conditions such as diabetes and cardiovascular disease.

Using computer models and live cell experiments, biomedical engineers at the Johns Hopkins University School of Medicine have discovered more than 100 human protein fragments that can slow or stop the growth of cells that make up new blood vessels.

The latest breakthrough in a 120 year-old debate on the evolution of the bird wing was published in the open-access journal PLoS ONE, October 3, by Alexander Vargas and colleagues at Yale University, the University of Wisconsin-Madison and Yale Peabody Museum of Natural History.

The melodious singing of birds has been long appreciated by humans, and has often been thought to reflect a particularly positive emotional state of the singer. In a new study published in the online, open-access journal PLoS ONE on October 1, researchers at the RIKEN Brain Science Institute in Japan have demonstrated that this can be true. When male birds sang to attract females, specific "reward" areas of their brain were strongly activated. Such strong brain activation resulted in a similar change in brain reward function to that which is caused by addictive drugs.