The open-access journal PLoS Biology has been assessed by Thomson ISI to have an impact factor of 13.9*, which places PLoS Biology among the most highly cited journals in the life sciences. This is an outstanding statistic for a journal less than two years old, from a new publisher promoting a new business model that supports open access to the scientific and medical literature.

University of Nevada, Reno scientists have ended a decade-long controversy over the process by which bark beetles make pheromones: they manufacture their own monoterpenes – the fragrant substances plants produce and which are often used in perfumes. It had been thought that insects and other animals were incapable of making these substances.

The Patagonian Hippidion horse genus and North American stilt-legged horses have found a new place on the evolutionary tree, according to a new article in the open access journal PLoS Biology. In the paper, Jaco Weinstock, Alan Cooper, and colleagues use ancient DNA to argue that the Hippidion genus is younger than previously thought and that American stilt-legged horses were American endemics, not Asian emigres. Their analysis has also whittled down the taxonomy of North American species to just two. "I think the biggest issue is that we showed the apparent lack of species diversity in North American horses in the Late Pleistocene - as horses are a poster child of evolution," says Cooper.

Linus Pauling's book Vitamin C and The Common Cold, published in 1970, was a bestseller and led many people to believe in the value of the vitamin for cold prevention and treatment. But an article in this month's PLoS Medicine reviewing all of the best clinical research on this topic, suggests that the public's enthusiasm for the vitamin may be unjustified.

Not all smokers are alike when it comes to cravings, and a new study conducted by researchers at Duke University Medical Center suggests the difference may lie in their brains' sensitivity to drug cues. The researchers found that smokers who report a greater urge to smoke after a period of abstinence also exhibit stronger brain activity after viewing smoking-related images, such as others smoking or a pack of cigarettes.

Mice given a relatively new cancer drug can survive an otherwise lethal dose of vaccinia virus, a relative of smallpox virus, report scientists supported by the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health. The findings, say the investigators, suggest that Gleevec or similar drugs might be useful in preventing adverse side effects of smallpox vaccine. The classic smallpox vaccine is made from live, weakened vaccinia virus and is not recommended for people with compromised immunity, except in emergency situations where they may have been exposed to smallpox virus.

The cellular cascade of molecular signals that instructs cells with fatally damaged DNA to self-destruct pivots on the p53 tumor suppressor gene. If p53 is inactivated, as it is in over half of all human cancers, checks and balances on cell growth fail to operate, and body cells start to accumulate mutations, which ultimately may lead to cancer. Not surprisingly, the regulation of this vital safeguard has been studied in great detail for many years but mainly in tissue culture, or in vitro, models.

Using technology that makes it possible to zoom in on smaller sections of cell chromosomes than ever before, researchers at Dana-Farber Cancer Institute have identified nearly 100 chromosome regions where genes are either over-copied or missing in non-small cell lung cancer. The findings provide new clues about the location of genes potentially involved in the most common type of lung cancer –– and one of the deadliest of all malignancies –– and a range of possible targets for future therapies.

In a study expected to greatly benefit crop plants, scientists have deciphered the genome of a root- and seed-dwelling bacterium that protects plants from diseases.

The research provides clues to better explain how the helpful microbe, Pseudomonas fluorescens Pf-5, naturally safeguards roots and seeds from infection by harmful microbes that cause plant diseases. The genome paper will be published in Nature Biotechnology and was scheduled to be posted online on June 26.