X-Ray Laser Pulses Reveal Key Parasite Enzyme

A new technique for determining a protein’s three-dimensional structure has revealed the inner workings of an important enzyme in Trypanosoma brucei, the parasite that causes sleeping sickness. Typically, researchers determine these structures by shining an X-ray beam onto a protein crystal. But, it’s difficult to grow crystals that are large enough to withstand this radiation for long enough to capture the necessary information. A new method, known as serial femtosecond crystallography, outruns the radiation-damage problem by using short X-ray laser pulses that radiate a steady stream of small crystals.

Read more about this research from the 29 November issue of Science Express here.

[Image courtesy of Michael Duszenko, University of Tübingen; click the image for more information.]

© 2012 American Association for the Advancement of Science. All Rights Reserved.

What Gives the Elephant Its Voice?

Elephants are great communicators and often converse with extremely low-pitched vocalizations, known as infrasounds, over vast distances. These infrasounds occupy a very low frequency range — lower than 20 Hertz, or cycles, per second — and they are sometimes too low to be perceived by human ears. But now, a new study from Christian Herbst of the University of Vienna and colleagues shows that elephants employ the same mechanism that produces sound in humans and many other mammals in order to hit those extremely low notes.

Watch a video and read more about this research from the 3 August issue of Science here.

[Photo by Angela S. Stoeger. Click the image for more information.]

© 2012 American Association for the Advancement of Science. All Rights Reserved.

Cell Biology Word of the Week: Membrane Potential

What it means: The electrical charge (voltage) across the plasma membrane of a cell.

Why you should care: When at rest, the inside of one of your body’s cells has a negative voltage with respect to the outside of the cell. (In most mammalian cells, the inside is charged at about -50mV.) When perturbed by a mechanical action like stretching or a chemical agent such as a neurotransmitter, the membrane potential of a cell may transiently change, triggering something called hyperpolarization, which lets negatively charged ions in and positively charged ions out, or the reverse process, called depolarization. So, changes in membrane potential can change cell behavior, causing muscle cells to contract or endocrine cells to release hormones. They can also generate electrical impulses that travel as signals through the nervous system.

Read about some recent research in Science involving membrane potentials here and here.

[Click the image for caption information.]

© 2012 American Association for the Advancement of Science. All Rights Reserved.

Is Seaweed the Next Biofuel?

Scientists have engineered E. coli bacteria to digest the sugars found in brown seaweed into ethanol, making the algae plant a potential source for renewable fuels and chemicals. Researchers and the energy industry have their eyes set on seaweed for two main reasons: its high sugar content makes for good biomass, and seaweed does not compete with food crops for land or fresh water.

Read more about this research from the 20 January issue of Science here.

[Photo courtesy of Bio Architecture Lab, Inc.; click the image for caption information.]

© 2012 American Association for the Advancement of Science. All Rights Reserved.

© 2014 American Association for the Advancement of Science. All Rights Reserved.