RESEARCH ROUNDUP

Scientists show landscape corridors
promote plant diversity

Landscape corridors – thin strips of habitat that connect isolated patches of habitat – are lifelines for native plants that live in the connected patches and therefore are a useful tool for conserving biodiversity.

Patches of land connected by landscape corridors (top, middle) are more effective than unconnected patches (top left and right, bottom) in retaining native plants, according to a paper published in Science.

That’s the result of the first replicated, large-scale study of plants and how they survive in both connected patches of habitat – those utilizing landscape corridors – and unconnected patches. Scientists at NC State and collaborators at other U.S. universities conducted the study.

Patches of habitat connected by corridors contained 20 percent more plant species than unconnected patches at the end of the five-year study, says Dr. Ellen Damschen, the study’s lead author and a postdoctoral researcher at the University of California, Santa Barbara. Damschen completed her Ph.D. in the lab of Dr. Nick Haddad, associate professor of zoology at NC State and a co-author of the paper describing the research.

The research appeared in the Sept. 1 edition of the journal Science.

The study also suggests that corridors provided the largest benefit to native species while having no effect on the number of invasive plant species. Invasive species seem to already be everywhere, not needing corridors for their spread, Damschen says. These results indicate that using corridors in conservation should provide benefits to native species that outweigh the risk of furthering the spread of exotic species.  

Jamboree yields celebration
of knowledge, Science paper

Sometimes it takes a jamboree to really understand a plant pathogen.
Certainly that was the case in August 2004, when Dr. Kelly Ivors, assistant professor of plant pathology who is stationed at the Mountain Horticultural Crops Research and Extension Center in Fletcher, N.C., joined other scientists for what was called the Phytophthora Genome Sequence Jamboree at the U.S. Department of Energy’s Joint Genome Institute in Walnut Creek, Calif.

Ivors’ work at that 2004 jamboree and as a post-doctoral researcher at the University of California-Berkeley played a role in the development of a scientific paper published Sept. 1 in the journal Science.

Ivors joined approximately 35 other scientists at the jamboree to annotate, or identify and predict the function of, genes from two species of Phytophthora: Phytophthora sojae and Phytophthora ramorum. The two Phytophthora species were chosen for genome sequencing due to their importance as plant pathogens – P. sojae causes root rot on soybean and is a major limitation to soybean production in the United States; Phytophthora ramorum causes sudden oak death.

In the paper, the researchers identified nearly 16,000 predicted gene locations in P. ramorum and more than 19,000 gene locations in P. sojae, and determined that the two Phytophthoras share roughly 10,000 genes. Ivors said they were also able to make educated guesses as to the function of many genes based on protein coding sequences from the genomes of other sequenced organisms.

“Tongue Drive” device
offers solution for disabled

What do orthodontic braces and trendy tongue piercing have in common?

They were the inspiration for an NC State engineer’s design for a new assistive device that allows quadriplegics to take greater control of their lives.

Dr. Maysam Ghovanloo, assistant professor of electrical and computer engineering, has developed the Tongue Drive system – an innovative interface that holds promise to be the next generation of assistive devices for people with severe disabilities such as spinal cord injuries or degenerative diseases.

The basic device consists of three components: a tiny permanent magnet the size of a rice grain, which is coated with gold or platinum and can be attached to the tongue by means of piercing or implantation; a set of very tiny magnetic sensors held in place by brackets on the lower or upper teeth, much like an orthodontic dental retainer; and a control unit. The control unit – comprised of sensor interface circuitry, wireless transmitter and a pair of watch batteries – is contained in a coin-sized, custom-designed sealed package that rests inside the mouth in the area under the tongue.

The Tongue Drive system uses wireless transmission to communicate with a basic PDA (personal digital assistant) or nearby computer using Bluetooth or Wi-Fi technology. Ghovanloo’s team has written software to decode the signals from the mouth sensors, translate them to user commands, and then communicate the commands to the specified device, such as a computer, powered wheelchair, telephone or television. Using the tongue much like a hand on a computer mouse, a person can move the pointer and give complex commands such as “drag-and- drop” or “double-click” with specific tongue movements.

Ghovanloo is collaborating with doctors at WakeMed Rehab Hospital in Raleigh to test the prototypes.

Chemical weapons debris in landfills
would pose minimal risk, models suggest

Putting building debris contaminated by chemical weapons into municipal landfills likely would pose only a minimal risk to nearby communities and the surrounding environment, according to a study published in the July 1 issue of the American Chemical Society journal Environmental Science & Technology.

The study’s computer model, developed by environmental engineers at NC State and the Technical University of Denmark, could help policymakers and waste management officials determine what to do with these harmful materials if another terrorist attack occurs.

The study will need to be verified by laboratory research, cautions Dr. Morton Barlaz, professor of civil, construction and environmental engineering. But, he adds, the finding is an important first step toward clarifying whether these potentially lethal compounds, including sarin, mustard gas and VX, could be safely contained in a municipal landfill.

Concerns about contaminated building debris arose following the Sept. 11, 2001, terrorist attacks on the World Trade Center and the Pentagon as well as the later discovery of anthrax in a U.S. Senate office building, postal facilities in Washington, D.C., and Trenton, N.J., and several buildings owned by media corporations.

The computer model predicted that virtually all of the compounds would bind themselves to organic waste in the landfill. In addition, most chemical warfare agents are rapidly transformed into less toxic forms when they come into contact with water in the landfill. The computer simulation also allowed the researchers to analyze the potential for contaminated gas emissions from a landfill as well as the potential for chemical agent movement through the landfill liner into groundwater.

To validate the model’s findings, Barlaz and his colleagues are conducting laboratory experiments using surrogates, such as malathion, that mimic the behavior of chemical agents but are safer to handle.

Scientists characterize protein
linked to Alzheimer’s

NC State scientists have effectively lifted the veil from an important protein that is linked to the prevention of neurodegenerative diseases like Alzheimer’s and Huntington’s.

Dr. John Cavanagh, professor of molecular and structural biochemistry, teamed with colleagues from the Mayo Clinic and Duke University to describe the shape of the protein, calbindin-D_28K. Understanding a protein’s structure allows researchers to learn more about how it functions and interacts with other proteins, which, in this case, may provide clues to developing drugs to halt the diseases.

Using nuclear magnetic resonance, scientists characterized the structure of calbindin-D28K , a flexible protein linked to the prevention of neurodegenerative diseases.

The research appeared in the July 2006 edition of Nature Structural and Molecular Biology.

Calbindin-D_28K is a protein that either grabs calcium from areas that have too much or serves as an on/off switch for further chemical reactions. It is known for its flexibility; it is found in the kidneys, pancreas, ocular nerve and in abundant quantities in the brain.

Cavanagh says recent studies have shown that it acts as a bodyguard in the brain, binding to and inhibiting caspase-3, a protein that stimulates plaque formation and tangle formation, which are hallmark characteristics of neurodegenerative disease. Until now, however, the structure of calbindin-D_28K remained a mystery.

“If you don’t know the shape of the protein, you can’t figure out how it works,” Cavanagh says. “Insight into how it binds to caspase-3 might lead to a way of exploiting those interactions to develop therapeutics.”

Posted September 8, 2006

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