Critically endangered species reproduced
Black-footed ferrets, a critically endangered species native to North America, have renewed hope for future survival after being reproduced successfully using frozen sperm.
A coalition of conservationists, including scientists at Lincoln Park Zoo, used frozen semen from a ferret which died 20 years ago. The sire, Scarface, as he is affectionately called by the team, was one of the last 18 black-footed ferrets in the world in the 1980s.
Eight kits, including offspring of Scarface, were born recently, increasing the gene diversity of this endangered population.
The conservationists' work was published in the journal Animal Conservation last week.
In a statement by Lincoln Park Zoo, lead author David Wildt, head of the Centre for Species Survival at the Smithsonian Conservation Biology Institute, said: "Our study is the first to provide empirical evidence that artificial insemination with long-stored spermatozoa is not only possible, but also beneficial to the genetic diversity of an endangered species.
For several years, his researchers have developed an artificial insemination technique in which the male's thawed sperm is injected directly into the female's uterus.
While other black-footed ferrets have been reproduced in captivity from both fresh and frozen sperm, particularly starting in 2008 with more frozen sperm, some of that reproductive material was only 10 years old.
"Our findings show how important it is to bank sperm and other biomaterials from rare and endangered animal species over time," said Mr Paul Marinari, senior curator at the Smithsonian Conservation Biology Institute.
"These 'snapshots' of biodiversity could be invaluable to future animal conservation efforts, which is why we must make every effort to collect, store and study these materials now."
Young minds think alike, older ones get distracted
Young people respond in a similar way to events but, as we age, our thought patterns diverge and we get more easily distracted, according to scientists at the University of Cambridge. In their study, published in the journal Neurobiology Of Ageing, researchers at the Cambridge Centre for Ageing and Neuroscience showed 218 subjects aged 18 to 88 an edited version of an episode from the Hitchcock TV series while using functional magnetic resonance imaging to measure their brain activity. This was done to try to understand how people respond to complex, lifelike stimuli.
The researchers found a surprising degree of similarity in the thought patterns among the younger subjects, their brains tending to "light up" in similar ways and at similar points in the programme.
However, in older subjects, this similarity tended to disappear and their thought processes became more idiosyncratic, suggesting that they were responding differently to what they were watching and were possibly more distracted.
The greatest differences were seen in the "higher order" regions at the front of the brain, which are responsible for controlling attention and language processing.
The findings suggest that a person's ability to respond to everyday events in the environment differs with age, possibly due to altered patterns of attention.
In a statement from the university, Dr Karen Campbell from the Department of Psychology and first author on the study, said: "As we age, our ability to control the focus of attention tends to decline, and we end up attending to more 'distracting' information than younger adults. As a result, older adults end up attending to a more diverse range of stimuli and, so, are more likely to understand and interpret everyday events in different ways than younger people."
'Brainy' mice raise hope of better treatments
Researchers have successfully altered a gene in mice that resulted in enhanced cognitive abilities, making them learn faster, remember events for a longer time and solve complex exercises better than ordinary mice. The altered gene inhibited the activity of an enzyme called phosphodiesterase-4B (PDE4B), which is present in many organs of the vertebrate body, including the brain.
The "brainy mice" showed a better ability than ordinary mice to recognise another mouse that they had been introduced to the day before.
According to a statement by the University of Leeds, which had researchers involved in the study, the mice were also quicker at learning the location of a hidden escape platform in a test called the Morris water maze, and showed less recall of a fearful event after several days than ordinary mice.
The researchers are now working on developing drugs that will specifically inhibit PDE4B. These drugs will be tested in animals to see whether any would be suitable for clinical trials in humans.
Dr Alexander McGirr, a psychiatrist in training at the University of British Columbia who co-led the study, said: "In the future, medicines targeting PDE4B may potentially improve the lives of individuals with neurocognitive disorders and life-impairing anxiety, and they may have a time-limited role after traumatic events."
Compiled by Samantha Boh