Stories tagged virology

May
24
2009

Antigenic shift in flu viruses: is when at least two different strains of a virus combine to form a new subtype having a mixture of the surface antigens of the two original strains.
Antigenic shift in flu viruses: is when at least two different strains of a virus combine to form a new subtype having a mixture of the surface antigens of the two original strains.Courtesy National Institute of Allergy and Infectious Diseases (NIAID)

Model of H1N1 flu virus takes shape

Genetic analysis of the new H1N1 virus shows that the hemagglutinin (the H in H1N1) and two other genes are from the 1918 Spanish flu virus and have been living in pigs ever since. Studies also show that the neuraminidase (the N in H1N1) segment is from the Eurasian swine flu virus that probably leaped from birds to pigs in about 1979.

The new virus differs in 21 of 387 amino acids from the H5N1 virus and the 1918 Spanish flu (also an H1N1 virus). - Singapore’s Agency for Science and Technology Research report in Biology Direct.

Shape shifting viral surface challenges vaccination success

"Viruses isolated from patients during the first two weeks of the current outbreak already have changes on the outer surface on the neuraminidase protein that could interfere with antibodies against the virus or alter the effectiveness of future vaccines. But none of the changes have altered the parts of the protein targeted by antiviral drugs, such as Tamiflu or Relenza." Science News

Learn more
If you click through to the source article in Science News, you will see a great three dimensional model of the influenza A/H1N1 virus with the origin of each of the virus's pieces explained.

Apr
17
2006


Watch Battery: Courtesy BatteryWeb

Researchers are turning to nature to develop miniature batteries. In a recent issue of Science, it was reported that an international team of researchers, led by a group at Massachusetts Institute of Technology, has used a virus to build miniature batteries.

How does a virus build a battery?

The batteries are being built from nanowires constructed from the M13 virus. Researchers modified the M13 virus’ genetic code so its outer coat would bond to certain metals. They incubated the modified virus in a cobalt chloride solution to allow cobalt oxide crystals to form uniformly along its length then sprinkled it with gold to produce electrical effects. Thus, the final nanowires worked as positive battery electrodes.

So why use a virus?
A virus is capable of forming tons of genetically similar copies of itself when grown under appropriate conditions. In the case of the M13 virus, it was harvested (or grown) in a bacteria. The M13 virus, in the bacteria environment, multiplied recreating tons of genetically similar copies of itself. Researchers reported that viruses form orderly layers yielding nanowires.

Future goals…
The researchers reported they have already used viruses to construct semiconductors and magnetic nanowires. Next on the agenda, they are hoping to use viruses to construct batteries ranging from the size of a grain of rice up to the size of a hearing aid battery. That’s pretty tiny!

Feb
02
2006

Professor Stephen Fuller and some colleagues at Oxford University's Wellcome Trust Centre for Human Genetics have created a map of the 3-D structure of the virus (HIV) that causes AIDS.

They used a technique called cryo-electron tomography to see the virus. The technique has been used to look at the virus before, but its unusual variability in size and shape makes it hard to map. The Oxford scientists used a computer program to combine 100 images of 70 individual viruses. They looked for similarities to create a never-before-seen image of the virus' structure. (Read the original paper, published in the journal Structure.)

[IMAGE: To come]
[Caption: HIV, 60 times smaller than a red blood cell, is way too small to be seen with an ordinary microscope. Electron microscopes and x-rays can "see" it, but the images usually aren't great because the virus varies in size and shape. The variation is one of the unique features of HIV; most viruses are much more uniform.]

The shape of a killer

HIV particles, like other viruses, aren't cells but strands of genetic material wrapped in proteins. Viruses hijack living cells by replacing the cell's genetic code with their own, and then reproducing quickly. (Read about the life cycle of HIV and see an animation of how it all works.)

Scientists think that the size and shape variability that makes HIV hard to image is key to the virus' success, and they wondered how HIV, unlike other viruses, is so varied without losing its crucial structure. The new image provides some insight: the cone-shaped core of the virus spans the width of the viral membrane. Usually, the internal structure of a virus defines its size. But HIV's membrane determines its size instead, and limits the way it can assemble.

Understanding how the virus grows and assembles will help researchers develop new therapies for people infected with HIV.

Make it at the museum

A virus uses one protein over and over again to build a shape that encloses its RNA. HIV makes a geometric shape called an icosahedron—it has 20 identical triangular sides. HIV is an unusual virus—its internal structure is asymmetrical.

On Saturday, February 4, the Make It team will be on hand to help you make a virus model of your own to take home!