04.06.2012

drug resistant malaria

Malaria is still a big killer across the globe, especially in more tropical climes. Now signs of resistance are beginning to show. From Scientific American:

The malaria parasite is a wily organism, shifting its life stages as it flits from human to mosquito and back again. It still kills some 600,000 people each year and has outwitted eradication efforts, having developed resistance to previously popular drugs and, thus far, eluded vaccine-induced immunity.

The arrival of a powerful drug in the late-20th century gave researchers new hope. Called artemisinin and based on a traditional Chinese herbal remedy, it cleared the parasite faster and more thoroughly than any other current antimalarial. Researchers are still somewhat uncertain about exactly how it works, but they know that it targets the parasite as it infects red blood cells.

But the hope that artemisinin would serve as a final, exterminanting blow against malaria has begun to fade. Since 2008 patients in Southeast Asia have been slower to lose the malaria parasite Plasmodium falciparum than they once were. And this precursor to resistance seems to be spreading, despite efforts to carefully use artemisinin (by giving it in combination with other drugs) to avoid the emergence of resistance.

Science magazine has a report on the development of drug-resistant malaria on its website.

04.06.2012

Three teams of scientists have made progress identifying gene mutations that may lead to autism. They have also found further evidence autism risk increases among older parents, especially when the father is over age 35. Three unaffiliated groups have completed studies that are published on the website of the journal Nature this week. From a summary of the research findings in the New York Times:

The three research teams took a similar approach, analyzing genetic material taken from blood samples of families in which parents who have no signs of autism give birth to a child who develops the disorder. This approach gives scientists the opportunity to spot the initial mutations that accompany the condition, rather than trying to work though possible genetic contributions from maternal and paternal lines. In all three studies, the researchers focused on rare genetic glitches called de novo mutations.

De novo mutations are not inherited but occur spontaneously near or during conception. Most people have at least one, and the majority of them are harmless.

In one of the new studies, Dr. Matthew W. State, a professor of genetics and child psychiatry at Yale, led a team that looked for de novo mutations in 200 people who had been given an autism diagnosis, as well as in parents and siblings who showed no signs of the disorder. The team found that two unrelated children with autism in the study had de novo mutations in the same gene — and nothing similar in those without a diagnosis.

“That is like throwing a dart at a dart board with 21,000 spots and hitting the same one twice,” Dr. State said. “The chances that this gene is related to autism risk is something like 99.9999 percent.”

More here. [New York Times]

“De novo mutations revealed by whole-exome sequencing are strongly associated with autism” [Nature, abstract available]

04.06.2012

another day

Another use for graphene. Like I said in the last post, graphene is a wonderous material. Today’s magical graphene finding is that it can be used in microscopy to investigate molecules on the atomic level. From Scientific American:

A liquid graphene bubble lets researchers view molecules inside at the atomic level. Image from Scientific American. Image courtesy of Alivisatos, Lee and Zettl research groups, Lawrence Berkeley National Laboratory and KAIST

In the April 6 issue of Science, a team from Lawrence Berkeley National Laboratory, the University of California, Berkeley, and the Korea Advanced Institute of Science and Technology in Daejeon, South Korea, reports that liquids fare just fine inside the vacuum of an electron microscope when encapsulated in graphene. The researchers sandwiched nanoscale pockets of liquid between two sheets of graphene and then used a transmission electron microscope to peer inside.

They found that the graphene capsules shielded the fluid from vacuum while also allowing for atomic-resolution imaging, which had been a challenge for other liquid capsules fashioned from materials such as silicon nitride. “The problem with that is the silicon nitride is already 25 nanometers thick. It’s a lot thicker than graphene,” says Jungwon Park, a U.C. Berkeley graduate student and a co-author of the new study. “It scatters a lot of the electron beam out, and it reduces the resolution and contrast a lot.”

The walls of the graphene liquid capsule, on the other hand, are so slim—less than a nanometer thick—that the researchers could resolve individual platinum atoms inside.

More here [Scientific American] and here [Science, abstract available].

GOLLYGEE!

Date: 04.06.2012

drug resistant malaria

a big leap in autism research

another day