UPI NewsTrack Health and Science News

Chestnut trees might slow climate change

WEST LAFAYETTE, Ind., June 10 (UPI) -- A U.S. study shows introducing a hybrid of the American chestnut tree would not only help the nearly extinct species, but also reduce atmospheric carbon.

Purdue University Associate Professor Douglass Jacobs said the study found American chestnuts grow much faster and larger than other hardwood species, allowing them to sequester more carbon. And since American chestnut trees are more often used for high-quality hardwood products such as furniture, they hold the carbon longer than wood used for paper or other low-grade materials.

"Maintaining or increasing forest cover has been identified as an important way to slow climate change," said Jacobs. "The American chestnut is an incredibly fast-growing tree. Generally the faster a tree grows, the more carbon it is able to sequester … (and) the carbon can be stored in hardwood products for decades.

At the beginning of the last century, chestnut blight caused by a fungus spread throughout the American chestnut's natural range, decimating the species.

New efforts to hybridize the remaining American chestnuts with blight-resistant Chinese chestnuts have resulted in a species that's about 94 percent American chestnut, but with the protection found in the Chinese species. Jacobs said those new trees could be ready to plant within the next decade.

He and his colleagues report their research in the journal Forest Ecology and Management.

Nightmares may be suicide risk factor

SEATTLE, June 10 (UPI) -- Severe nightmares have been independently associated with elevated suicidal symptoms, U.S. researchers said.

Rebecca Bernert, a doctoral candidate in clinical psychology at Florida State University, said the study included 82 men and women between the ages of 18-66, who were in a community mental health hospital admissions unit awaiting an emergency psychiatric evaluation.

Evaluations determined eligibility for crisis stabilization inpatient admittance. Patients' nightmares, insomnia, depression and suicidal tendencies were assessed through several questionnaires.

"Sleep disturbances, especially nightmares, appear to be an acute warning sign and risk factor for suicide," Bernert said in a statement. "Given that poor sleep is amenable to treatment, and less stigmatized than depression and suicide, our findings could impact standardized suicide risk assessment and prevention efforts."

The findings suggest that nightmares stand alone as a suicide risk factor, Bernert said.

Bernert said the findings of the study emphasize the need for a more thorough assessment of sleep among acutely ill patients, as it may be an important opportunity for intervention.

The findings were presented at Sleep, the 23rd annual meeting of the Associated Professional Sleep Societies in Seattle.

Scientists determine how snakes slither

ATLANTA, June 10 (UPI) -- U.S. researchers have determined snakes use both friction generated by their scales and redistribution of their weight to slither along flat surfaces.

Scientists at New York University and the Georgia Institute of Technology say their finding runs counter to previous studies that have shown snakes move by pushing laterally against rocks and branches.

"We found that snakes' belly scales are oriented so that snakes resist sliding toward their tails and flanks," the paper's lead author, former post-doctoral researcher David Hu, said. Hu is now an assistant professor at Georgia Tech.

"These scales give the snakes a preferred direction of motion, which makes snake movement a lot like that of wheels, cross-country skis or ice skates," Hu added. "In all these examples, sliding forward takes less work than does sliding sideways."

The study, which included Jasmine Nirody, Terri Scott and Professors Michael Shelley and George Lyttle, is reported in the Proceedings of the National Academy of Sciences.

Scientists report unusual enzyme structure

CHAMPAIGN, Ill., June 10 (UPI) -- U.S. scientists have discovered the structure of an unusual enzyme that can break the bond between two carbon atoms in a single step.

University of Illinois researchers said their findings might help determine how bacteria develop resistance to new drugs and how to create drugs that overcome that resistance.

The scientists said they have, for the first time, described the three-dimensional structure of hydroxyethylphosphonate dioxygenase and proposed a mechanism by which the enzyme causes chemical reactions. The enzyme catalyzes a critical step in the production of phosphinothricin, a compound that is widely used as an agricultural herbicide.

"Our team discovered this very implausible chemical reaction," said Professor Wilfred van der Donk. "And the more we learned about it the more unusual it became. The enzyme is unusual because it breaks a carbon-carbon bond without needing anything except oxygen."

The researchers said their findings result from an ongoing study of molecules containing carbon-phosphorus bonds. Compounds using such molecules inhibit cellular processes in bacteria or other organisms and are used in agriculture and medicine.

Those compounds, van der Donk said, are candidates for the development of new antibiotics.

The study, which included Professor William Metcalf, appears in the journal Nature.