University of Utah biologists genetically manipulated nematode worms so the animals were attracted to worms of the same sex – part of a study that shows sexual orientation is wired in the creatures’ brains.

“They look like girls, but act and think like boys,” says Jamie White, a postdoctoral researcher and first author of the new study. “The [same-sex attraction] behavior is part of the nervous system.”

The study was published Thursday, Oct.

Nearly a third of the world’s 6,000 amphibian species are threatened with extinction and more than 120 species have already vanished from the planet.

Across the globe, conservation organisations and professionals are mobilising efforts to help save as many of these species as possible.

A brightly coloured tropical frog under threat of extinction is the focus of a new research project hoping to better understand how environment and diet influence its development and behavior.

The shortage of islet cells limits the development of islet transplantation. One new approach was reported in the October 21 issue of the World Journal of Gastroenterology because of its great significance in enhancing the output of islet cells.

The article describes the differentiation of rat pancreatic ductal epithelial cells into insulin-producing cells by the transfection of PDX-1. In recent years, though great efforts have been made to differentiate embryonic stem cells, pancreatic ductal epithelial multipotent progenitor cells and bone marrow stem cells into islet cells, the process of cell differentiation and growth is long. Moreover, the amount of islet cells of differentiation, and the insulin released by islets, is not enough to meet the clinical needs.

The greatest mass extinction in Earth’s history also may have been one of the slowest, according to a study that casts further doubt on the extinction-by-meteor theory.

Creeping environmental stress fueled by volcanic eruptions and global warming was the likely cause of the Great Dying 250 million years ago, said USC doctoral student Catherine Powers.

Writing in the November issue of the journal Geology, Powers and her adviser David Bottjer, professor of earth sciences at USC, describe a slow decline in the diversity of some common marine organisms.

More than 250 million women worldwide smoke tobacco. Compared to men, women have a greater risk of smoking-related diseases, and also have more difficulty quitting. A new study, the first of its kind, has found that cigarette smoking and having a family history of alcoholism have different effects on sweet-taste perception and food cravings.

“Tobacco is one of the most heavily used addictive drugs,” said M. Yanina Pepino, a researcher at the Monell Chemical Senses Center in Philadelphia and corresponding author for the study, “leading to an increased risk of lung and heart diseases and a variety of cancers.” In fact, lung cancer has surpassed breast cancer as the leading cause of death among US women, she added.

Severely restricting calories leads to a longer life, according to research in the October issue of Journals of Gerontology Series A: Biological Sciences and Medical Sciences.

The study says such a diet can also maintain physical fitness into advanced age, slowing the seemingly inevitable progression to physical disability and loss of independence.

Using a rat model of life-time caloric restriction, they showed that the diet reduces the amount of visceral fat, which expresses inflammatory factors that in humans cause chronic disease and a decline in physical performance and vitality across the lifespan.