Science Briefs: Sickle cells combat malaria, loss of hemlocks could affect forest water cycles, surprising new use for bubbles

Sickle cells combat malaria

Researchers at Duke University Medical Center may finally have discovered why people with sickle cell disease get milder cases of malaria than individuals who have normal red blood cells.

In a finding that has eluded scientists for years, Duke researchers discovered that genetic material in red blood cells may help alter parasite activity via a novel mechanism that changes parasite gene regulation.

“One of the most interesting findings in our study is that the human microRNA (very small units of genetic material) found in sickle red cells directly participate in the gene regulation of malaria parasites,” said Dr. Jen-Tsan Chi, senior author and associate professor in the Duke Institute for Genome Sciences and Policy and Department of Molecular Genetics and Microbiology. “These microRNAs enriched in the sickle red cells reduce the parasite’s ability to propagate, so that certain people stay more protected.”

The scientists also showed that when two different microRNAs were introduced at higher levels in normal red cells, the parasite growth also was decreased. The findings appear in the journal Cell Host & Microbe.

Loss of hemlocks could affect forest water cycles

The loss of eastern hemlock could affect water yield and storm flow from forest watersheds in the southern Appalachians, according to a new study by U.S. Forest Service scientists at the Coweeta Hydrologic Laboratory, in southwest North Carolina. The article was just published online in the journal Ecohydrology.

“Eastern hemlock trees have died throughout much of their range due to the hemlock woolly adelgid, an exotic invasive insect,” said Steven Brantley, a researcher at Coweeta and lead author of the paper.

Because of its dense evergreen foliage, eastern hemlock plays an important role in the water cycle of southern Appalachian forests, regulating stream flow yearround. Although eastern hemlock rarely dominates the region’s forests, the tree is considered a foundation species in the streamside areas called riparian zones.

Previous research led the Coweeta scientists to suspect that the loss of eastern hemlock would cause stream flow to increase over the short term, especially in the dormant fall/winter season, then decrease over the long term, with small effects annually. They also thought that peak flows after storms would increase, especially in the dormant season.

Surprising use for common bubbles

Everyone knows that the bubbles in a glass of fizzy soda can throw tiny particles into the air. But in a finding with wide industrial applications, Princeton researchers have demonstrated that the bursting bubbles push some particles into the liquid as well.

“We were surprised, and fascinated, to discover that when we covered the water with oil, the same process injected tiny oil droplets into the water,” said Princeton engineering professor Howard Stone, the lead researcher for the project. The conclusions provide new insight into the mixture of nonsoluble liquids – a process at the center of many fields, from drug manufacturing to oil spill cleanups.

In an article in Nature Physics, the researchers detail how the bubbles burst and how that affected the oil and water mix. In one observation, researchers noted that water in one container changed from clear to translucent after bubbles ran through the mixture for some time. The change in appearance “suggested that small objects had been dispersed in the lower water phase.”