Cryptococcus neoformans, causes more than a million cases of lung and brain infe

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Posted: Sunday, Nov. 21, 2010

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Researchers at N.C. State University have found a way to optimize the length of

DNA strands so they achieve a " Goldilocks " result - not too long, not too short,

but just right.

The finding holds promise for technologies ranging from drug delivery to

molecular sensors.

DNA strands contain genetic coding that will form bonds with another strand

containing a unique sequence of complementary genes. When a material is coated

with a specific DNA layer, that material will then seek out and bond with its

complementary counterpart.

The phenomenon, known as DNA-assisted self-assembly, has long held potential in

the biomedical and materials science fields, but it has been problematic. DNA

segments that are too short often failed to self-assemble, while segments that

are too long often led to the creation of deformed materials.

The NCSU team, along with collaborators at the University of Melbourne, in

Australia, may have found a solution, using computer simulations of DNA strands

to identify the optimal length of a DNA strand for self-assembly - and

explaining the scientific principles behind it.

" The optimal lengths are not long enough to intertwine with each other, and are

not short enough to fold over on themselves, " said Yara Yingling, an assistant

professor of materials science and engineering at NCSU and co-author of a paper

describing the research.

Duke researchers target a killer fungus

DURHAM A discovery in how a killer fungus reproduces could give scientists a way

of attacking the infection, scientists at Duke University report.

The pathogenic fungi, called Cryptococcus neoformans, causes more than a million

cases of lung and brain infections a year, and more than half of those infected

die. A related species has been blamed for an expanding outbreak in the Pacific

Northwest, raising public health concerns.

But the fungus may have a weakness. The organism has been found to protect

itself against unwanted genetic mutations during sexual reproduction, using a

gene-silencing pathway that keeps it from being vulnerable to potentially

harmful mutations.

Sexual reproduction in fungi produces airborne spores that are readily inhaled

into the lungs and thought to be the source of human infections. Thus, agents

that block fungal sex might stop the risk of infection at the source.

" This discovery of how the genome is protected during sex might be leveraged as

an Achilles' heel in the battle against C. neoformans, which frequently causes

life-threatening illness in people, " said Dr. ph Heitman, chairman of the

Duke Department of Molecular Genetics and Microbiology and senior author of the

report. Staff reports

What toddlers notice

Understanding another's intent is an important skill, and a new study shows

toddlers can do it.

Children as young as 3 are less likely to help a person after they have seen

them harm someone else - in this case adult actors tearing up or breaking

another adult's drawing or clay bird - according to researchers from the Max

Planck Institute for Evolutionary Anthropology in Germany.

More intriguing is that the toddlers judged a person's intention. When one

person tried to harm someone else but did not succeed, the youngsters were less

likely to help that person later. But when they saw a person accidentally harm

another, they were more willing to help that person. New York Times

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