MAR 04, 2015 09:15 AM PST

Huge Virus Exposed in 3-D with X-ray Laser

WRITTEN BY: Judy O'Rourke
4 48 3851
For the first time, researchers have produced a 3-D image revealing part of the inner structure of an intact, infectious virus, using a unique X-ray laser at the Department of Energy's SLAC National Accelerator Laboratory. The virus, called Mimivirus, is in a curious class of "giant viruses" discovered just over a decade ago.

The experiment establishes a new technique for reconstructing the 3-D structure of many types of biological samples from a series of X-ray laser snapshots.
This computerized rendering shows a cutaway view of a collection of about 200 X-ray patterns, produced in an experiment at SLAC's Linac Coherent Light Source X-ray laser. The images were combined to produce a 3-D rendering of an intact Mimivirus, a giant virus that was at first mislabeled as a bacterium because of its size.
"Ever since I started in this field of X-ray laser research, this has always been the dream - to acquire 3-D images of real biological samples," says Tomas Ekeberg, PhD, biophysicist, Uppsala University, Sweden, and lead author of the study, published March 2 in Physical Review Letters. "This is fantastic - it's a breakthrough in our research."

Mimivirus is so big - its volume is thousands of times larger than the smallest viruses and even larger than some bacteria - that it was misclassified as a bacterium until 2003. Subsequent discoveries have found other giant viruses, some of which are even larger.

Mimivirus is also genetically complex, with nearly 1,000 major genes compared to only a handful in the HIV virus.

Scientists have been trying to determine the inner structure of these giant viruses to learn more about their origins: For example, did they borrow genes over time from the host organisms they infect, like amoebas? Did they precede cell-based life or devolve from cell-based organisms?

"We can see quite clearly that the inside of these viruses is not uniform," Ekeberg says.

This same general feature had also been seen before using an electron-based imaging technique with frozen samples, and LCLS allows studies of viruses and other biological samples in a more natural, intact state. Researchers said that LCLS shows promise for achieving sharper images that reveal more inner details in the future because of the uniquely intense, penetrating power of its X-rays.

The same technique was recently used to study bacterial cell structures. LCLS managers have launched an initiative with the scientific community to improve techniques for imaging intact, biological particles that are difficult to study.

"The next Holy Grail is to study large, single proteins at LCLS," says Janos Hajdu, PhD, professor, biophysics, Uppsala, and a pioneer in biological particle imaging.

[Source: SLAC National Accelerator Laboratory]
About the Author
  • Judy O'Rourke worked as a newspaper reporter before becoming chief editor of Clinical Lab Products magazine. As a freelance writer today, she is interested in finding the story behind the latest developments in medicine and science, and in learning what lies ahead.
You May Also Like
JUN 12, 2018
Genetics & Genomics
JUN 12, 2018
Giant Viruses can Make Their own Genes
Researchers have discovered something incredible about giant viruses.
JUN 22, 2018
Microbiology
JUN 22, 2018
Antiviral Compound Found in the Human Body
The human body can make a compound with a special power to fight viruses - an enzyme called viperin.
JUL 07, 2018
Microbiology
JUL 07, 2018
A New Target for an Effective Gonorrhea Treatment
Many pathogens are becoming antibiotic resistant; the microbe that causes the STD gonorrhea is no different.
JUL 19, 2018
Microbiology
JUL 19, 2018
Mom's Microbiome has a Big Impact on Kid's Autism Risk
For many years, scientists have been trying to learn more about the causes of autism.
JUL 28, 2018
Videos
JUL 28, 2018
Separating Microbial Fact From Fiction
Can the toilet really send germs flying to your toothbrush?
AUG 13, 2018
Genetics & Genomics
AUG 13, 2018
A Kind of Forensics to ID the Source of Bacterial Outbreaks
Scientists at Mayo Clinic have developed a way to use whole genome sequencing to locate the source of deadly bacterial pathogens.
Loading Comments...