Molecular Movie

Researchers Create Molecular Movie of Virus Preparing to Infect Healthy Cells

With SLAC’s X-ray laser, scientists captured a virus changing shape and rearranging its genome to invade a cell.

A research team has created for the first time a movie with nanoscale resolution of the three-dimensional changes a virus undergoes as it prepares to infect a healthy cell. The scientists analyzed thousands of individual snapshots from intense X-ray flashes, capturing the process in an experiment at the Department of Energy’s SLAC National Accelerator Laboratory.

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Growing a better polio vaccine

Researchers use plants as factories to produce a safer polio vaccine

Successful vaccination campaigns have reduced the number of polio cases by over 99% in the last several decades. However, producing the vaccines entails maintaining a large stock of poliovirus, raising the risk that the disease may accidentally be reintroduced.
Outbreaks can also occur due to mutation of the weakened poliovirus used in the oral vaccine. In addition, the oral vaccine has to be stored at cold temperatures. To address these shortcomings, an international team of researchers across the UK has engineered plants that produce virus-like particles derived from poliovirus, which can serve as a vaccine.
They report the success of this approach in a paper appearing in Nature Communications. The team confirmed the structure of the virus-like particles by cryo-electron microscopy at Diamond Light Source’s Electron Bio-Imaging Centre (eBIC) and showed that the particles effectively protected mice from infection with poliovirus. This proof-of-principle study demonstrates that a safe, effective polio vaccine can be produced in plants and raises the possibility of using the same approach to tackle other viruses.

Diving into magnets

First-time 3D imaging of internal magnetic patterns

Magnets are found in motors, in energy production and in data storage. A deeper understanding of the basic properties of magnetic materials could therefore impact our everyday technology. A study by scientists at the Paul Scherrer Institute PSI in Switzerland, the ETH Zurich and the University of Glasgow has the potential to further this understanding.

The researchers have for the first time made visible the directions of the magnetisation inside an object thicker than ever before in 3D and down to details ten thousand times smaller than a millimetre (100 nanometres). They were able to map the three dimensional arrangement of the magnetic moments. These can be thought of as tiny magnetic compass needles inside the material that collectively define its magnetic structure. The scientists achieved their visualisation inside a gadolinium-cobalt magnet using an experimental imaging technique called hard X-ray magnetic tomography which was developed at PSI. The result revealed intriguing intertwining patterns and, within them, so-called Bloch points.

At a Bloch point, the magnetic needles abruptly change their direction. Bloch points were predicted theoretically in 1965 but have only now been observed directly with these new measurements. The researchers published their study in the renowned scientific journal Nature.

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Image: A vertical slice of the internal magnetic structure of a sample section. The sample is 0.005 millimetres (5 micrometres) in diameter and the section shown here is 0.0036 millimetres (3.6 micrometres) high. The internal magnetic structure is represented by arrows for a vertical slice within it. In addition, the colour of the arrows indicate whether they are pointing towards (orange) or away from the viewer (purple). (Graphics: Paul Scherrer Institute/Claire Donnelly)

Photonic structure of white beetle wing scales: optimized by evolution

They have developed a complicated three-dimensional photonic structure on their wing scales in order to efficiently reflect white light.

At the same time, this structure is very porous and is confined within a thin layer of about 10  µm, about one fifth of the thickness of ordinary white paper, which makes it very light and therefore advantageous to fly.

Researchers of the University of Fribourg and their collaborators wanted to understand how this fascinating structure is optimized, for which they needed a faithful 3D image. However, conventional microscopy techniques providing enough spatial resolution such as electron microscopy required the sample to be cut for imaging consecutive slices, causing damage of the structure during the process.

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Image: Cyphochilus white beetle source: PSI