For the first time in nearly 50 years, a population of a nearly extinct frog has been rediscovered in the San Bernardino National Forest's San Jacinto Wilderness. Biologists from the U.S. Geological Survey (USGS) assessing suitability of sites to re-establish frogs and scientists from the San Diego Natural History Museum retracing a 1908 natural history expedition both rediscovered the rare mountain yellow-legged frog in the San Jacinto Wilderness near Idyllwild, Calif.

The mechanism used by 'Natural Killer' immune cells in the human body to distinguish between diseased cells, which they are meant to destroy, and normal cells, which they are meant to leave alone, is revealed in new detail in research published today (Tuesday 28 July) in PLoS Biology.

Scientists from the Université de Montréal and McGill University have re-engineered a human enzyme, a protein that accelerates chemical reactions within the human body, to become highly resistant to harmful agents such as chemotherapy, according to a new study published in The Journal of Biological Chemistry.

An international team of scientists has discovered an extinct rodent species, based on fossil tooth remains found in Alborache, Valencia. Eomyops noeliae, from the Eomyidae family, represents the oldest find within this genus in the world.

Cancer researchers are turning to mathematical models to help answer important clinical questions, and a new paper in Cancer Research, a journal of the American Association for Cancer Research, illustrates how the technique may answer questions about Herceptin resistance.

Walter and Eliza Hall Institute scientists have created a weakened strain of the malaria parasite that will be used as a live vaccine against the disease. The vaccine, developed in collaboration with researchers from the US, Japan and Canada, will be trialled in humans from early next year.

The first ever genetic linkage map for a non-avian member of the Class Reptilia has been developed. Researchers writing in the open access journal BMC Genomics have constructed a first-generation genetic linkage map for the saltwater crocodile Crocodylus porosus.

Hungry, sexual organisms replaced well-fed, clonal organisms in the Caribbean Sea as the Isthmus of Panama arose, separating the Caribbean from the Pacific, report researchers from the Smithsonian Tropical Research Institute and Scripps Institution of Oceanography. The fossil record shows that if a species could shift from clonal to sexual reproduction it survived. Otherwise it was destined for extinction, millions of years later.

A new urine test developed with funding from the Wellcome Trust will allow doctors to diagnose Chlamydia infection in men within the hour, improving the ability to successfully treat the infection on the spot and prevent re-transmission.