Cut off one finger from a salamander and one will grow back. Cut off two and two will grow back. It sounds logical, but how the salamander always regenerates the right number of fingers is a biological mystery.

The salamander isn't the only animal with this regenerative ability. Take the sea squirt, Ciona intestinalis, a cylindrical marine creature about the size of a small cucumber that regularly loses its siphons, or feeding tubes, to hungry predators.

At the base of each siphon are eight photoreceptors, cells used to detect light. Whenever the sea squirt experiences a violent loss at the siphon base, the number of photoreceptors that grow back is always eight.

Cells are intrinsically artistic. When the right signals tell a cell to divide, it usually splits down the middle, resulting in two identical daughter cells, though stem cells are the exception to the rule. This natural symmetry is visible on the macroscopic scale as well. All living creatures, be they mushrooms or humans, are visibly symmetric, a product of our cells' preference for equilibrium.

Scientists at the Marine Biological Laboratory (MBL) Whitman Center for Visiting Research are curious to know what cues tell a cell to divide at the center. Fred Chang, professor of microbiology at Columbia University, his postdoctoral student Nicolas Minc, and David Burgess, professor of biology at Boston College, are placing sea urchin eggs in snug, microscopic chambers shaped like triangles, squares, rectangles, stars, and ice cream cones to see whether the cell will still split 50-50.

The International AIDS Vaccine Initiative (IAVI) and Key Thought Leaders Explore Critical Next Steps for AIDS Vaccine Research at the 17th International AIDS Conference in Mexico City.

Today, they write, AIDS vaccine research is at a pivotal moment. Just ten months ago, the second AIDS vaccine candidate to reach late-stage testing failed. In the wake of this disappointment, some skeptics have argued that an AIDS vaccine may not be possible and that resources dedicated to its development should be directed instead towards treating HIV-infected individuals.

Almost every metropolitan area in America has a "dead man's curve", a road notorious for fatalities. If you've moved to a new location, you may not know of it. Using the interactive maps on www.saferoadmaps.org developed by University of Minnesota researchers, you can learn which roads near your home or work are considered dangerous simply typing in your address.

Researchers in the Center for Excellence in Rural Safety (CERS) have mapped out every fatality in the nation with details on each death.

A scientist at the University of Liverpool has found that hypnosis can slow down the impacts of dementia and improve quality of life for those living with the condition.

Forensic psychologist, Dr Simon Duff, investigated the effects of hypnosis on people living with dementia and compared the treatment to mainstream health-care methods. He also looked at how hypnosis compared to a type of group therapy in which participants were encouraged to discuss news and current affairs.

Scientists hope a vaccine is on the horizon for tularemia, a fatal disease caused by the pathogen Francisella tularensis, an organism of concern as a potential biological warfare agent. Until recently we knew very little about this bacterium. However, according to the August issue of the Journal of Medical Microbiology, research on the bacterium has been reinvigorated and rapid progress has been made in understanding how it causes disease.

Infection with F. tularensis can result in a variety of symptoms, depending on the route of infection. For example, infection via an insect bite can lead to a swollen ulcer or fever, chills, malaise, headaches and a sore throat. When infection occurs by eating
contaminated food, symptoms can range from mild diarrhoea to an acute fatal disease.

Bacteria living on opposite sides of a canyon have evolved to cope with different temperatures by altering the make-up of their 'skin', or cell membranes, write scientists who have found that bacteria change these complex and important structures to adapt to different temperatures by looking at the appearance of the bacteria as well as their genes. The researchers hope their study, published in the August issue of Microbiology, will start a new trend in research.

The cell membrane is one of the most important and complex parts of a cell. Membranes contain different fatty acid molecules; the branching type can change depending on temperature to keep the cell alive. The researchers found significant differences in the fatty acids of several ecotypes that live on different slopes in Evolution Canyon.

'Evolution Canyons' I and II are in Israel. They are similar, each with a hot south-facing slope and a cooler north-facing slope. The sun-exposed 'African' south-facing slopes get eight times more solar radiation than the shady, green, lush 'European' north-facing slopes. Scientists studied 131 strains of Bacillus simplex and found that bacteria on different slopes have evolved differently, forming different 'ecotypes' of the same species.

Typhoid fever kills 10–30% of untreated people. One of the best-known cases was that of Mary Mallon, a healthy carrier of typhoid, who worked for many years in the food industry in New York and is thought to have infected almost 50 people. She was eventually forcibly quarantined by authorities and named Typhoid Mary.

There are 17 million cases of Typhoid fever each year - although the World Health Organization cautions that this is a 'very conservative' estimate. Young people are most at risk: in Indonesia, nine out of ten cases occur in 3–19-year-olds.

It has been controlled by vaccination and use of antibiotics but antibiotic resistance is an emerging problem, especially in south-east Asia.

Knowledge of the structure–property–function relationships of dermal scales of armoured fish could enable pathways to improved bioinspired human body armor, and may provide clues to the evolutionary origins of mineralized tissues.

Writing in Nature Materials, researchers Benjamin J. F. Bruet, Juha Song, Mary C. Boyce and Christine Ortiz present a multiscale experimental and computational approach that reveals the materials design principles present within individual ganoid scales from the 'living fossil' Polypterus senegalus.

This fish belongs to the ancient family Polypteridae, which first appeared 96 million years ago during the Cretaceous period and still retains many of their characteristics.

A new discovery could lead to treatments which turn off the inflammation in the lungs caused by influenza and other infections, according to a study published today in the journal Nature Immunology.

The symptoms of influenza, such as breathlessness, weight loss and fever, are made much worse by the immune system responding in an exaggerated way to the virus, rather than by the virus itself. The virus is often cleared from the body by the time symptoms appear and yet symptoms can last for many days, because the immune system continues to fight the damaged lung.