In yesterday’s issue of Nature, we published a paper from Amir Hoveyda‘s and Mark Snapper’s groups at Boston College. The paper describes a simple metal-free catalyst that can perform enantioselective catalytic silylations on a variety of meso 1,2-diols, obtaining mono-protected chiral diols.

In the accompanying News & Views article, Scott Denmark wrote

The chemical yields and enantiomeric selectivities of the reactions are very good – in some cases, excellent – although the reaction times are long (2-3 days). Relatively large amounts of the catalyst are required, but this is not a problem as the catalyst is simple to prepare from inexpensive starting materials. Clearly this is just the beginning of a development process and more active catalysts will be forthcoming.

These kinds of catalysts could shave several steps off synthetic routes to prostaglandin analogues, unnatural nucleosides, and neocarzinostatin analogues, which currently require a number of chemical transformations and an enzymatic de-acylation to obtain a key building block. By shortening the synthetic route, the amount of chemical waste produced can be minimized and the amount of time needed to make the molecule can be dramatically reduced. Denmark concludes the News & Views article by saying that

this procedure is likely to have a significant impact on the efficiency and cost of constructing single-enantiomer products. Most importantly, however, this report demonstrates the creative power of synthetic chemistry to build simple organic catalysts that mimic and ultimately surpass, biological catalysts – especially for non-biological transformations.

Collaborations between two well-known organic chemistry labs aren’t extremely common, and Hoveyda talked about this phenomenon on our ‘Authors’ page:

Hoveyda says the synthetic organic chemistry field has traditionally been wary of two principal investigators sharing credit on single papers. “The culture almost discourages it,” he says. Early on, colleagues warned Snapper that working with a more senior researcher could hurt his career. But their partnership has been fruitful; the two have received joint grants from the National Institutes of Health since 1997 and have published about 20 papers together. “The reason this collaboration has been so successful is that neither of us cares who gets the credit,” Hoveyda adds.

If you’d like to learn more about the research, Hoveyda was interviewed on this week’s Nature Podcast (he also appears on the recent chemistry podcast). And if you’re in San Francisco at the Fall ACS Meeting next week, you can see Yu Zhao talk about the work on Monday afternoon.

Joshua

Joshua Finkelstein (Associate Editor, Nature)

The genetics of blindness, mental illness from Hurricane Katrina, and how the brain finds meaning in images.

Pat McCaffrey

A clearer look at age-related blindness

Researchers from the Massachusetts Eye and Ear Infirmary and the Broad Institute have discovered a common gene variant associated with an increased risk of macular degeneration, the leading cause of blindness in people over 60. Along with the novel variant, they confirmed four other sequence variations, or polymorphisms, spanning three genes, which all together appear to increase the chances of developing this disabling disease by more than 250-fold. The study appeared this week in the online edition of Nature Genetics.

Age-related macular degeneration (AMD), the destruction of the part of the retina involved in fine vision, is a result of a combination of genetic and environmental factors. To pin down the genetic component, Johanna Seddon of the Massachusetts Eye and Ear Infirmary and Harvard Medical School, along with Mark Daly and colleagues at the Broad Institute, surveyed 1,536 of one type of genetic variation, called single nucleotide polymorphism, in three AMD susceptibility genes. They studied more than 2,000 subjects age 60 or older, more than half of which had AMD.

Their testing revealed five common variants that each increased disease susceptibility in the study group. By determining whether each of these five markers were of the low-risk or high-risk type, the researchers could estimate an individual’s risk for AMD, ranging from a low of one percent in people without any of these markers, to a high of more than 50 percent in those with all five.

The recognition that multiple common genetic variants can predispose people to a complex disease like AMD suggests that common variants could have a large effect on the risk of developing other complex disorders like Alzheimer’s disease, diabetes, or heart disease. A similar intensive analysis of common variation in large groups of patients may put a sharper focus on disease risk.

Katrina survivors show high rates of mental illness, but also resilience

A study published Monday, one year after Hurricane Katrina struck Mississippi and Louisiana, shows that people who weathered the storm subsequently suffered serious mental illness at twice the rate of those living in the affected areas before the hurricane. Yet despite a dramatic increase in depression and anxiety, survivors were not more likely to consider suicide. The reasons for this, according to the study, were their optimism about the future and a confidence that their situation would improve.

“This finding documents a psychological strength in the population affected by Hurricane Katrina that is, at least temporarily, linked to an unexpectedly low prevalence of suicidality,” writes lead author Ronald Kessler of Harvard Medical School. But this apparent resilience could merely postpone despair in the short term, the authors caution, if recovery efforts do not meet the expectations of hurting but hopeful survivors.

To assess the mental health of survivors, researchers tracked down 1,043 people from Katrina-affected areas for phone interviews four to six months after the hurricane. Pre-hurricane baseline rates of mental illness in the same area were established from local responses to a national survey done between 2001 and 2003. Post hurricane, 11 percent of survivors fit the criteria for a serious mental illness, such as depression, posttraumatic stress, panic, or anxiety, and 20 percent displayed mild mental illness, compared to 6 and 10 percent, respectively, in the pre-hurricane sample. The rate of suicide thoughts or attempts did not increase in the survivors group.

The lack of suicide thoughts or attempts was apparent in survivors who expressed an increasing realization of their own inner strengths and a belief in their ability to recover from the disaster.

The study, part of a continuing follow-up of Katrina victims, appeared online in the Bulletin of the World Health Organization.

Brain cells identified that add meaning to visual input

When a Toyota Prius driver sees a Hummer on the road, she doesn’t waste a minute trying to identify the kind of foreign object entering her field of view. Her brain registers “car,” despite the obvious differences between her own vehicle and the one coming toward her. The ability of our brains to categorize objects we see in a split second—road, person, tree—provides us a kind of visual shorthand that gives meaning to our surroundings and allows us to perform complicated tasks, like driving a car.

Harvard Medical School investigators recently identified the neurons in the brain that are responsible for this ability to quickly size up and sort visual stimuli. Using monkeys trained to play a simple video game, David Freedman and John Assad found that neurons in the parietal cortex, a part of the outer layer at the top of the brain, became electrically active in response to a game that required the monkeys to classify objects into groups based on the object’s direction of movement. The same neurons responded differently when the monkeys were later retrained to sort the same objects into different categories.

A lot is known about how the brain perceives simple visual features like color, but little is known about how it learns the meaning of more-complex stimuli. The discovery that the parietal cortex neurons activate in response to categories of moving objects, rather than just to their absolute direction, shows the importance of these cells in transforming visual information into abstract ideas about the meaning of stimuli. Since meaning of this kind is often learned through experience, the findings will also help us understand the brain processes behind learning and memory.

The study appeared online this week in Nature.