Crohn’s is a condition that affects one in 800 people in the UK and causes chronic intestinal inflammation, leading to pain, bleeding and diarrhoea.

The team found that a bacterium called Mycobacterium paratuberculosis releases a molecule that prevents a type of white blood cell from killing E.coli bacteria found in the body. E.coli is known to be present within Crohn’s disease tissue in increased numbers.

It is thought that the Mycobacteria make their way into the body’s system via cows’ milk and other dairy products. In cattle it can cause an illness called Johne's disease - a wasting, diarrhoeal condition. Until now, however, it has been unclear how this bacterium could trigger intestinal inflammation in humans.

Researchers discovered genetic evidence that human evolution is speeding up – and has not halted or proceeded at a constant rate, as had been thought – indicating that humans on different continents are becoming increasingly different.

“We used a new genomic technology to show that humans are evolving rapidly, and that the pace of change has accelerated a lot in the last 40,000 years, especially since the end of the Ice Age roughly 10,000 years ago,” says research team leader Henry Harpending, a distinguished professor of anthropology at the University of Utah.

Harpending says there are provocative implications from the study, published Dec. 10 in the journal Proceedings of the National Academy of Sciences:

LONDON, December 10 /PRNewswire/ --

- New research announced this week has found an association between certain genes and the severity of multiple sclerosis (MS).

The results of the study by Prof George Ebers, Chair of Clinical Neurology at the Wellcome Trust Centre for Human Genetics, will be published in the journal Proceedings of the National Academy of Sciences and represent a step forward in the understanding of the role of genetics in MS.

The study involved comparing genes from people with severe MS who used wheelchairs within five years of being diagnosed and people who had no disability 20 years after diagnosis.

Imagine you are sitting around a campfire. If you move closer to the fire you get hotter. If you move awayy ou get cooler. Pretty basic, right?

Our closest star, the sun, doesn't follow those rules. As you move away from the solar surface, into the sun's outer atmosphere (the corona) it actually gets a lot hotter before it cools off. The solar surface is about 10,000 degrees Fahrenheit, while temperatures in the corona soar to millions of degrees.

Although scientists have some ideas of what might heat the solar corona, there is no universally accepted explanation.

Countering a common theory that human evolution has slowed to a crawl or even stopped in modern humans, a new study examining data from an international genomics project describes the past 40,000 years as a time of supercharged evolutionary change, driven by exponential population growth and cultural shifts.

In a study published in the Dec. 10 issue of the Proceedings of the National Academy of Sciences (PNAS), a team led by UW-Madison anthropologist John Hawks estimates that positive selection just in the past 5,000 years alone — around the period of the Stone Age — has occurred at a rate roughly 100 times higher than any other period of human evolution.

You study the menu at a restaurant and decide to order the steak rather than the salmon. But when the waiter tells you about the lobster special, you decide lobster trumps steak. Without reconsidering the salmon, you place your order—all because of a trait called “transitivity.”

“Transitivity is the hallmark of rational economic choice,” says Camillo Padoa-Schioppa, a postdoctoral researcher in HMS Professor of Neurobiology John Assad’s lab. According to transitivity, if you prefer A to B and B to C, then you ought to prefer A to C. Or, if you prefer lobster to steak, and steak to salmon, then you will prefer lobster to salmon.

Some anti-drinking advertising campaigns may be “catastrophically misconceived” because they play on the entertaining ‘drinking stories’ that young people use to mark their social identity, say researchers who have just completed a three year study of the subject.

Adverts that show drunken incidents, such as being thrown out of a nightclub, being carried home or passing out in a doorway, are often seen by young people as being a typical story of a ‘fun’ night out, rather than as a cautionary tale.

Whilst these adverts, such as Diageo’s thechoiceisyours campaign, imply that being very drunk with friends carries a penalty of social disapproval, for many young people the opposite is often the case.

While the biological basis for homosexuality remains a mystery, a team led by University of Illinois at Chicago researcher David Featherstone has discovered that sexual orientation in fruit flies is controlled by a previously unknown regulator of synapse strength.

Armed with this knowledge, the researchers found they were able to use either genetic manipulation or drugs to turn the flies' homosexual behavior on and off within hours.

Featherstone, associate professor of biological sciences at UIC, and his coworkers discovered a gene in fruit flies they called "genderblind," or GB. A mutation in GB turns flies bisexual.

One gene for pea pod color generates green pods while a variant of that gene gives rise to the yellow-pod phenotype, a feature that helped Gregor Mendel, the 19th century Austrian priest and scientist, first describe genetic inheritance. However, many modern-day geneticists are focused on the strange ability of some genes to be expressed spontaneously in either of two possible ways.

In order to better understand this phenomenon of epigenetic multistability, a major complication for Mendelian genetics, scientists at UC San Diego grew virtual bacterial cells in a computer experiment. They created a two-phenotype model system programmed to grow in ways that matched natural growth.

Policy makers, employers and others can use the science of behavioral economics to steer people toward wiser choices — and dramatically improve their health — without limiting their freedom to do as they please, according to an article in the Journal of the American Medical Association (JAMA). The paper was written by researchers at Carnegie Mellon University, the University of Pennsylvania, Aetna Inc. and the Philadelphia Veterans Affairs Medical Center.

This approach can counter one of the underlying causes of major health problems in the United States and other developed nations — bad decision-making on the part of individuals. Tobacco use, obesity and alcohol abuse account for nearly one-third of all deaths in the United States.