A new study puts some old folk wisdom to "feed a cold and starve a fever" to the test. In mouse models of disease, Yale researchers looked at the effects of providing nutrients during infection and found opposing effects depending on whether the infections were bacterial or viral. Mice with bacterial infections that were fed died, while those with viral infections who were fed lived. The paper appears September 8 in Cell.

Today's industrial yeast strains are used to make beer, wine, bread, biofuels, and more, but their evolutionary history is not well studied. In a Cell paper publishing September 8, researchers describe a family tree of these microbes with an emphasis on beer yeast. The resulting genetic relationships reveal clues as to when yeast was first domesticated, who the earliest beer brewers were, and how humans have shaped this organism's development.

"The flavor of the beer we drink largely depends on yeast," explains Kevin Verstrepen, a yeast geneticist at the University of Leuven and VIB in Belgium. "We're drinking the best beers now because ancient brewers were smart enough to start breeding yeast before they knew what they were doing. It was really an art."

Up until now, scientists had only recognized a single species of giraffe made up of several subspecies. But, according to the most inclusive genetic analysis of giraffe relationships to date, giraffes actually aren't one species, but four. For comparison, the genetic differences among giraffe species are at least as great as those between polar and brown bears.

The unexpected findings reported in the Cell Press journal Current Biology on September 8 highlight the urgent need for further study of the four genetically isolated species and for greater conservation efforts for the world's tallest mammal, the researchers say.

Ants visually track the motion of objects as they move through their environment in order to determine the distance they have traveled, a new study reports. Such tracking, called optic flow, has been observed in a number of insects but was thought to be used only minimally by ants. Now, results by Sarah Elisabeth Pfeffer and Matthias Wittlinger suggest that certain ants can rely solely on optic flow to find their way back to their nest when lost. Here, they studied Cataglyphis bicolor desert ants, which exhibit unique behaviors; namely, experienced forager ants carry interior nest workers, who are much less familiar with the outdoor environment, between different nest sites.

Scientists have shown that a two-pronged antibody can counteract the unique immune-evasion mechanism that filoviruses like Ebola have evolved. This is a critical step on the road to developing treatments that protect broadly against ebolaviruses, for which there remains an urgent need. Filoviruses including Ebola have an unusual route into the host cell; they access the inside of cells through tiny transport vesicles, or endosomes, where they interact with a specific host-cell receptor called NPC1, and then become unmasked. In effect, this two-step pathway acts as a shield -- hiding the virus from the immune system and hindering the potency of anti-viral therapies.

Researchers have developed a large culturing device to track the evolution of bacteria as they mutate in the presence of antibiotics, revealing that, surprisingly, the fittest mutants were not those most likely to infiltrate higher antibiotic concentrations. Instead, bacteria "behind" the very fittest on the growth plate became capable of surviving at highest antibiotic concentrations. The results provide important insights into the evolutionary patterns and mechanisms that drive bacteria's success in overcoming antibiotics, a phenomenon that threatens human health worldwide.