Scientists seeking to understand how to make an AIDS vaccine have found the cause of a major roadblock. It turns out that the immune system can indeed produce cells with the potential to manufacture powerful HIV-blocking antibodies – but at the same time, the immune system works equally hard to make sure these cells are eliminated before they have a chance to mature.

An international team of Canadian and Spanish scientists have found the first potential immunological clue of why some people develop severe pneumonia when infected by the pandemic H1N1 virus.

Free infectious HIV-1 is widely thought to be the major form of the virus in the blood of infected persons. U.S. Military HIV Research Program (MHRP) researchers, however, have demonstrated that essentially all of the infectious virus particles can bind to the surface of red blood cells isolated from each of 30 normal (non-infected) human donors. The results were published today in PLoS ONE, and can be accessed here.

Extinct woolly mammoths and ancient American horses may have been grazing the North American steppe for several thousand years longer than previously thought. After plucking ancient DNA from frozen soil in central Alaska, a team of researchers used cutting-edge techniques to uncover "genetic fossils" of both species locked in permafrost samples dated to between 7,600 and 10,500 calendar years. This new evidence suggests that at least one population of these now-extinct mammals endured longer in the continental interior, challenging the conventional view that these and other large species, or megafauna, disappeared from the Americas about 12,000 years ago.

Bacteria dance the electric slide, officially named electrokinesis by the USC geobiologists who discovered the phenomenon.

New research shows how the migration and settlement patterns associated with the rapid urbanization of Peru may link to Chagas disease transmission. The study, published December 15 in the open-access journal PLoS Neglected Tropical Diseases, suggests that the practice of shantytown residents from Arequipa making frequent seasonal moves to rural valleys where Chagas vectors are present may have contributed to the growing presence of Chagas disease near urban Arequipa, Peru.