Scientists capture first super-res X-rays of living cells

While lower-energy "soft" X-rays can already image living cells, the higher-energy "hard" ones that can view objects as small as a few nanometers haven't been able to -- until now.

 

To avoid damaging the cells, the researchers exposed them for only 0.05 seconds at a time, but still managed to image nanometer-scale structures. Britta Weinhausen/University of Göttingen

Typically, to view super small objects like molecules, the samples must first be dipped in a chemical preservative bath of death that keeps all parts entirely locked in place and thus viewable via very sophisticated tech such as X-ray devices and electron microscopes. The problem, of course, is that those molecules don't behave the same in death as they do in life, so while our current views of life at the nanoscale level are extremely detailed, they're technically speaking views of death, or at the very least, life frozen.

Now scientists at the University of Göttingen in Germany say that, using a new approach with one of the world's most sophisticated X-ray machines, the Petra III, they've been able to view -- however briefly -- actual living cells in their natural environment.

Reporting in the journal Physical Review Letters, the researchers say they grew cancer cells from the adrenal cortex on a silicon nitrate substance that is nearly transparent to X-rays. They then fed those cells nutrients and pumped away their metabolic products so that they could keep the cells alive in as close to a natural environment as possible while still being viewable by the higher-energy (aka "hard" X-ray) Petra III. While lower-energy "soft" X-rays can already image living cells, the resolution isn't as good.

Related stories
3D X-ray provides window into heart health
With X-ray tech, scientists can peer inside cells
Researchers accelerate proton cancer treatment

To avoid killing the cells with the powerful X-ray beams, they exposed the sample in a series of frames that each lasted a mere 0.05 seconds. They then used this same nanodiffraction approach on chemically fixed cells for comparison and found that their cellular structures were noticeably different when viewed on a scale of 30 to 50 nanometers (that is, millionths of a millimeter).

While this initial test was performed using extremely brief and powerful blasts on petri dish cancer cells, the researchers say it offers evidence that we should be able to study living cells at super high resolution without first having to change their molecular behavior -- which could dramatically improve our understanding of life, including diseases and treatments, at the nanoscale level.

ORIGINAL: CNet

by Elizabeth Armstrong Moore @ejamoore
February 28, 2014

Researchers Japan find damage-free way to observe internal cell structures

Japanese scientists say they have developed the world’s first method to observe a live cell without damaging its internal structure.

The researchers said the procedure, using free-electron X-ray laser technology, will help advance an understanding of intracellular phenomena, such as the mechanism of cell division.

“By further improving performance, we will be able to take a look at smaller objects, as well as make closer observations of them,” said Yoshinori Nishino, an electronic science professor at Hokkaido University, who led the research team.

The team used the SACLA state-of-the-art X-ray facility in Hyogo Prefecture to expose bacteria, each 600 nanometers long, to a single dose of X-ray for 100-trillionth of a second. A nanometer is one-billionth of a meter.

An image taken at the SACLA X-ray facility in Hyogo Prefecture reveals a live cell’s internal structures. (Provided by Yoshinori Nishino)

It has been impossible to observe live cells using a conventional X-ray device because they become severely damaged. The new method also eliminates the need to fix cells’ internal structures with resin and stain them when using electron microscopy techniques.

The SACLA facility, set up by the RIKEN research institute and others at a cost of 39 billion yen ($372 million), enabled Nishino’s team to capture an image of bacteria almost free from damage.

According to the scientists, substances that appeared to be a gathering of DNA, the molecule that encodes genetic information, could be observed in the cells.

The findings were published in the British scientific journal Nature Communications on Jan. 7.

ORIGINAL: AJW

By JIN NISHIKAWA/ Staff Writer
January 08, 2014

Google celebrates Rosalind Franklin, British biophysicist and X-ray crystallographer

ORIGINAL: The Guardian

25 July 2013 Google Doodle: Rosalind Franklin (25 July 1920 - 16 April 1958). Today's Google Doodle honours pioneering British biophysicist and x-ray crystallographer, Rosalind Franklin

Rosalind Franklin. Wikipedia

Today is the 93rd anniversary of the birth of British biophysicist Rosalind Franklin, who was a pioneering x-ray crystallographer who is being honoured today with a special Google Doodle.

Nearly everyone who has heard about Dr Franklin knows that her work was critical to elucidating the structure and function of DNA -- a discovery that was recognised by the 1962 Nobel Prize in Physiology or Medicine four years after her tragic death from ovarian cancer. (Dr Franklin was not nominated for this award; Nobel Prizes are not awarded posthumously.)

Dr Franklin was an x-ray crystallographer. To do her work, she would purify a molecule, such as DNA, grow it into crystals and bombard the crystal with x-rays. After photographing the x-ray diffraction pattern created by collisions with atoms within the crystal (see right), Dr Franklin then could directly determine the structure of the molecule.

Photo 51

Dr Franklin's work, particularly "Photo 51" (pictured, right; by Raymond Gosling), was critical for correctly determining the structure and function of DNA. According to my sources, Maurice Wilkins, who was Dr Franklin's supervisor at King's College London, shared several of her images, including "Photo 51", with James Watson without her knowledge or consent. Up until the time when they saw this particular image, Watson and his colleague, Francis Crick, had erroneously postulated that the DNA "backbone" was on the inside of the molecule and the nucleic acid "bases" pointed outwards, like the teeth of a comb. This image pointed out their error in logic so they quickly revised their hypothesis and published it, which then led to them being awarded the Nobel Prize a few years later.

But this is where most people's knowledge of Dr Franklin's life ends: what did she do after her work with DNA crystals had concluded?

In fact, after finishing her work in Wilkin's lab in 1953, Dr Franklin left King's College to study the tobacco mosaic virus (TMV) at Birkbeck College in London. This is where she spent the last five years of her life, conducting pioneering work into the structure of viruses.

Electronmicrograph of Tobacco Mosaic Virus (TMV).
Image: T. Moravec (worldwide public domain.)

Discovered to be a virus in 1930, TMV is both stable and structurally simple, and thus, it easily forms crystals, making it an excellent candidate for x-ray crystallography studies. TMV also is easy to work with in the lab, being a highly infectious agricultural pest that attacks a wide variety of plant species. In susceptible plants, it causes obvious symptoms but doesn't kill its host plants, which also made it attractive for scientific study.

Finding Birkbeck College to be a much more collegial environment than King's College, Dr Franklin assembled a team of talented scientists whose researches complemented her own. Based on her team's findings, Dr Franklin hypothesized that TMV was a hollow tube made of proteins that contained a single strand of RNA that spiraled inside the length of the tube like a thread spiraling inside a donut hole -- both hypotheses were found to be correct after her death.

Solving the structure of a plant viruses meant that it would also be possible to solve the structure of other viruses -- animal viruses. Polio viruses were the obvious choice since they had been crystallized in 1955 (doi:10.1073/pnas.41.12.1020). For that reason, Dr Franklin sought funding necessary to solve the structure of the polio virus.

During a visit to the United States in 1956, Dr Franklin began suffering health problems that were soon diagnosed as ovarian cancer. After two abdominal surgeries in one month, she returned to the lab and redoubled her efforts. Although she felt fine for awhile, the cancer soon returned.

Despite her illness and impending death, Dr Franklin still managed to obtain funding to keep her team going for another three years, researching the polio virus. Shortly after her untimely death on 16 April 1958 at the age of 37 years old, two members of her team, John Finch and Aaron Klug, dedicated the resulting paper to her memory (doi:10.1038/1831709a0).

Throughout her professional life, Dr Franklin -- an unmarried female Jewish scientist -- was faced with tremendous challenges from most of her (white male) colleagues. But thanks to supportive environment at Birkbeck College, she was able to pursue her work in relative peace during her final years.

After her death, John Bernal who was chair of the physics department at Birkbeck College, wrote obituaries published in the New York Times and in Nature (doi:10.1038/182154a0) that celebrated her "beautifully executed researches, carried out with apparently effortless skill, and her gift for organizing research projects".

"As a scientist Miss Franklin was distinguished by extreme clarity and perfection in everything she undertook", Professor Bernal wrote.

"Her photographs are among the most beautiful x-ray photographs of any substance ever taken."

Dr Franklin's life, Professor Bernal concluded, was a perfect example of single-minded devotion to research.
Sources:

Rosalind Franklin: My Favourite Scientist

Biology%2CChemistry%2CHealth%2CMedicine">Schaffer F.L. (1955). Crystallization of Purified MEF-1 Poliomyelitis Virus Particles, Proceedings of the National Academy of Sciences, 41 (12) 1020-1023. doi:10.1073/pnas.41.12.1020

Bernal J.D. (1958). Dr. Rosalind E. Franklin, Nature, 182 (4629) 154-154. doi:10.1038/182154a0

Glynn J. (2008). Rosalind Franklin: 50 years on, Notes and Records of the Royal Society, 62 (2) 253-255. doi:10.1098/rsnr.2007.0052

Finch J.T. & Klug A. (1959). Structure of Poliomyelitis Virus, Nature, 183 (4677) 1709-1714. doi:10.1038/1831709a0

Creager, Angela N. H. & Morgan, Gregory J. (2008). After the Double Helix: Rosalind Franklin's Research on Tobacco
mosaic virus, Isis, 99 (2) 239-272. doi:10.1086/588626

.. .. .. .. .. .. .. .. .. .. ..

Grrlscientist can also be found here: Maniraptora, and she lurks on social media: facebook, Google +, LinkedIn, Pinterest and of course, she's quite active on twitter: @GrrlScientist