Secrets of the deadly white-tail virus revealed

The inner workings of a lethal giant freshwater prawn virus have been revealed by an international team of researchers using data gathered at Diamond Light Source. The results reveal a possible new class of virus and presents the prospect of tackling a disease that can devastate prawn farms around the world.

The detailed structure of a virus that can devastate valuable freshwater prawn fisheries has been revealed by an international team using image data collected in the Electron Bio-Imaging Centre (eBIC) based at Diamond Light Source. The researchers produced high-resolution images of virus like particles, VLP’s, composed of virus shell proteins which they compared with lower resolution images of the complete virus purified from prawn larvae. They found strong similarities between the two suggesting that the more detailed VLP images are a good representation of the intact virus. This research, exposing the inner workings of the MrNV, could make it easier to develop ways of combating the economically important disease, but also suggests that it belongs in a new, separate, group of nodaviruses.
The researchers used the rapidly developing technique of cryo-electron microscopy, cryoEM, which has the ability to produce very high-resolution images of frozen virus particles. Images so detailed that the positions of individual atoms could be inferred. Recent breakthroughs in this technique have transformed the study of relatively large biological complexes like viruses allowing researchers to determine their structures comparatively quickly. The data to produce the MrNV structure described here was captured in two days at the eBIC facility.

>Read more on the Diamond Light Source website

Image: 3D model of the MrNV
Credit: Dr David Bhella

Insights into an antibody directed against dengue virus

We are one step further to uncovering a new way to stave off dengue fever thanks to important work carried out at the I02 beamline at Diamond Light Source.

The study, recently published in Nature Immunology, describes how an antibody effectively targets the dengue virus.
Dengue virus affects hundreds of millions of people worldwide and is an untreatable infection. Secondary infections with dengue can lead to a life-threatening form of the disease due to a phenomenon called antibody-dependent enhancement (ADE). Additionally, efforts to develop a vaccine against the virus have been hindered by ADE.

A huge collaborative effort sought to investigate ADE in dengue, and two antibodies were characterised that bound to the envelope protein of the dengue virus. One of the antibodies was found to be a potent neutraliser of the virus, but importantly was unable to promote ADE.

>Read more on the Diamond Light Source website

Image: Fab binding in the context of the mature virion. e, Comparison of 2C8 Fab and 3H5 Fab docked onto a E dimer. 2C8 (green) and 3H5 (orange) Fabs were docked onto PDB ID 3J27 by aligning the EDIII potion of the structures. The Fabs are shown as surfaces and the E dimer is displayed in cartoon representation. A side view is of the E dimer on the viral surface is shown. The approximate location of the viral membrane is shown schematically.


Snaphot of molecular mechanism at work in lethal virus

X-ray crystallography at the Australian Synchrotron contributed to major research findings.

Data collected on the macromolecular crystallography beamlines at the Australian Synchrotron has contributed to major research findings on two deadly viruses, Hendra and Nipah, found in Australia, Asia and Africa. The viruses can be transmitted to humans not directly by the bat which is the natural carrier but by an infected animal like horses or pigs.

Beamline scientist, Dr David Aragao (pictured above), a co-author on the paper in Nature Communications, said that obtaining a clear motion picture of key biological process at the molecular level of viruses is often not available with current biomedical techniques.
“However, using X-ray crystallography from data collected on both MX1 and MX2 beamlines at the Australian Synchrotron, we were able to obtain  8  ‘photograph-like’ snapshots of the molecular process that allows the Hendra and Nipah virus to replicate.“

Two authors of the paper, PhD students Kate Smith and Sofiya Tsimbalyuk, who are co-supervised by Aragao and his collaborator Professor of Biochemistry Jade Forwood of the Graham Centre for Agricultural Innovation Charles Sturt University, used the Synchrotron extensively collecting multiple data sets that required extensive refinements over two years to isolate the mechanism of interest.

>Read more on the Australian Synchrotron website

Image: Beamline scientist, Dr David Aragao.

Respiratory virus study points to likely vaccine target

Scientists develop sugar-coated nanosheets to target pathogens

Molecular Foundry-designed 2-D sheets mimic the surface of cells

Researchers have developed a process for creating ultrathin, self-assembling sheets of synthetic materials that can function like designer flypaper in selectively binding with viruses, bacteria, and other pathogens.
In this way the new platform, developed by a team led by scientists at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab), could potentially be used to inactivate or detect pathogens.

The team, which also included researchers from New York University, created the synthesized nanosheets at Berkeley Lab’s Molecular Foundry, a nanoscale science center, out of self-assembling, bio-inspired polymers known as peptoids. The study was published earlier this month in the journal ACS Nano.
The sheets were designed to present simple sugars in a patterned way along their surfaces, and these sugars, in turn, were demonstrated to selectively bind with several proteins, including one associated with the Shiga toxin, which causes dysentery. Because the outside of our cells are flat and covered with sugars, these 2-D nanosheets can effectively mimic cell surfaces.

>Read more on the Advanced Light Source website

Image: A molecular model of a peptoid nanosheet shows loop structures in sugars (orange) that bind to the Shiga toxin (shown as a five-color bound structure at upper right).
Credit: Berkeley Lab

The search for an Ebola vaccine

Researchers expertly solved the crystal structures of drugs bound to the outer coating of the Ebola virus to pinpoint the regions that are essential for inhibitory activity.

Ebola is a viral disease that is highly infectious and associated with a high risk of death. It first arose in 1976, from which point it was associated with dozens of small-scale outbreaks; however, in 2013 Ebola was responsible for a huge epidemic in West Africa. Emergency was declared and over 11,000 people lost their lives to the virus. Despite this horrific state of affairs, Ebola still remains an untreatable disease and there is no vaccine to prevent infection.

>Read more on the Diamond Light Source website


World Polio Day

Are we nearing the end of the war on polio?

There was a time when the word itself was enough to strike fear into the hearts of people around the world. Polio: a highly infectious virus that could shatter young lives in the blink of an eye. On the 24th of October, we mark World Polio Day, and this is something worth celebrating. Because whilst the story isn’t over yet, it may well be nearing its end.

Polio has been around since before records began, but it wasn’t until the early-twentieth century that epidemics began to sweep through communities in Europe and America, affecting many thousands of children and families.

It’s hard to underestimate the terror once caused by polio. At its height in the 1950s, parents routinely lived in fear of their children becoming quarantined, paralysed or even worse. It was a dark time in medical history but, despite this, polio really is a success story for modern science.

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.

>Read More

From Community to Molecule – on Track Towards a Zika Vaccine

A potent new weapon against the Zika virus in the blood of people who have been infected by it.

A research team based at The Rockefeller University has identified a potent new weapon against the Zika virus in the blood of people who have been infected by it. This discovery could lead to new ways of fighting the disease. Detailed examination of the interaction between the virus and antibodies derived from human subjects in Brazil and Mexico, including crystallographic studies performed at the Stanford Synchrotron Radiation Lightsourse (SSRL), have revealed a new potential strategy for developing a vaccine towards this virus.

Through collaborators working in Pau da Lima, Brazil, and Santa Maria Mixtequilla, Mexico, the research team obtained blood samples from more than 400 people, collected shortly after Zika was circulating.

In these samples, antibodies that block the virus from initiating an infection were found. Interestingly, the antibodies appeared to have been initially generated in response to an earlier infection by a related virus (DENV1) that causes dengue fever. It appears that, much like a vaccine, the DENV1 virus can prime the immune system to respond to Zika.