Researchers Find New DNA Structure In Living Human Cells

Researchers Find New DNA Structure in Living Human Cells

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According to Breaking Science News

A team of scientists from the Garvan Institute of Medical Research and the Universities of New South Wales and Sydney has identified a new DNA structure — called the intercalated motif (i-motif) — inside living human cells.

Deep inside the cells in our body lies our DNA. The information in the DNA code — all 6 billion A, C, G and T letters — provides precise instructions for how our bodies are built, and how they work.

The iconic ‘double helix’ shape of DNA has captured the public imagination since 1953, when James Watson and Francis Crick famously uncovered the structure of DNA.

However, it’s now known that short stretches of DNA can exist in other shapes, in the laboratory at least — and scientists suspect that these different shapes might play an important role in how and when the DNA code is ‘read.’

“When most of us think of DNA, we think of the double helix. This research reminds us that totally different DNA structures exist — and could well be important for our cells,” said co-lead author Dr. Daniel Christ, from the Kinghorn Centre for Clinical Genomics at the Garvan Institute of Medical Research and St Vincent’s Clinical School at the University of New South Wales.

“The i-motif is a four-stranded ‘knot’ of DNA,” added co-lead author Dr. Marcel Dinger, also from the Garvan Institute of Medical Research and the University of New South Wales.

“In the knot structure, C letters on the same strand of DNA bind to each other — so this is very different from a double helix, where ‘letters’ on opposite strands recognize each other, and where Cs bind to Gs [guanines].”

Although researchers have seen the i-motif before and have studied it in detail, it has only been witnessed in vitro — that is, under artificial conditions in the laboratory, and not inside cells. In fact, they have debated whether i-motif DNA structures would exist at all inside living things — a question that is resolved by the new findings.

To detect the i-motifs inside cells, Dr. Christ, Dr. Dinger and their colleagues developed a precise new tool — a fragment of an antibody molecule — that could specifically recognize and attach to i-motifs with a very high affinity.

Until now, the lack of an antibody that is specific for i-motifs has severely hampered the understanding of their role.

Crucially, the antibody fragment didn’t detect DNA in helical form, nor did it recognize ‘G-quadruplex structures’ (a structurally similar four-stranded DNA arrangement).

With the new tool, the team uncovered the location of ‘i-motifs’ in a range of human cell lines.

Using fluorescence techniques to pinpoint where the i-motifs were located, the study authors identified numerous spots of green within the nucleus, which indicate the position of i-motifs.

The scientists showed that i-motifs mostly form at a particular point in the cell’s ‘life cycle’ — the late G1 phase, when DNA is being actively ‘read.’

They also showed that i-motifs appear in some promoter regions — areas of DNA that control whether genes are switched on or off — and in telomeres, ‘end sections’ of chromosomes that are important in the aging process.

“We think the coming and going of the i-motifs is a clue to what they do. It seems likely that they are there to help switch genes on or off, and to affect whether a gene is actively read or not,” said study first author Dr. Mahdi Zeraati, also from the Garvan Institute of Medical Research and the University of New South Wales.

“We also think the transient nature of the i-motifs explains why they have been so very difficult to track down in cells until now,” Dr. Christ added.

“It’s exciting to uncover a whole new form of DNA in cells — and these findings will set the stage for a whole new push to understand what this new DNA shape is really for, and whether it will impact on health and disease,” Dr. Dinger said.

The team’s results appear in the journal Nature Chemistry.

Chasing the Shadow of Neptune’s Moon Triton

Our Flying Observatory

Our flying observatory, called SOFIA, carries a 100-inch telescope inside a Boeing 747SP aircraft. Scientists onboard study the life cycle of stars, planets (including the atmosphere of Mars and Jupiter), nearby planetary systems, galaxies, black holes and complex molecules in space.

AND on Oct. 5, SOFIA is going on a special flight to chase the shadow of Neptune’s moon Triton as it crosses Earth’s surface!

In case you’re wondering, SOFIA stands for: Stratospheric Observatory for Infrared Astronomy.

Triton

Triton is 1,680 miles (2,700 km) across, making it the largest of the 13 moons orbiting Neptune. Unlike most large moons in our solar system, Triton orbits in the opposite direction of Neptune, called a retrograde orbit. This backward orbit leads scientists to believe that Triton formed in an area past Neptune, called the Kuiper Belt, and was pulled into its orbit around Neptune by gravity.

The Voyager 2 spacecraft flew past Neptune and Triton in 1989 and found that Triton’s atmosphere is made up of mostly nitrogen…but it has not been studied in nearly 16 years!

Occultations are Eclipse-Like Events

An occultation occurs when an object, like a planet or a moon, passes in front of a star and completely blocks the light from that star. As the object blocks the star’s light, it casts a faint shadow on Earth’s surface.

But unlike an eclipse, these shadows are not usually visible to the naked eye because the star and object are much smaller and not nearly as bright as our sun. Telescopes with special instruments can actually see these shadows and study the star’s light as it passes near and around the object – if they can be in the right place on Earth to catch the shadow.

Chasing Shadows

Scientists have been making advanced observations of Triton and a background star. They’ve calculated exactly where Triton’s faint shadow will fall on Earth! Our SOFIA team has designed a flight path that will put SOFIA (the telescope and aircraft) exactly in the center of the shadow at the precise moment that Triton and the star will align.

This is no easy feat because the shadow is moving at more than 53,000 mph while SOFIA flies at Mach 0.85 (652 mph), so we only have about two minutes to catch the shadow!! But our SOFIA team has previously harnessed the aircraft’s mobility to study Pluto from inside the center of its occultation shadow, and is ready to do it again to study Triton!

What We Learn From Inside the Shadow

From inside the shadow, our team on SOFIA will study the star’s light as it passes around and through Triton’s atmosphere. This allows us to learn more about Triton’s atmosphere, including its temperature, pressure, density and composition!

Our team will use this information to examine if Triton’s atmosphere has changed since our Voyager 2 spacecraft flew past it in 1989. That’s a lot of information from a bit of light inside a shadow! Similar observations of Uranus in 1977, from our previous flying observatory, led to the discovery of rings around that planet!

International Ground-Based Support

Ground-based telescopes across the United States and Europe – from Scotland to the Canary Islands – will also be studying Triton’s occultation. Even though most of these telescopes will not be in the center of the shadow, the simultaneous observations, from different locations on Earth, will give us information about how Triton’s atmosphere varies across its latitudes.

This data from across the Earth and from onboard SOFIA will help researchers understand how Triton’s atmosphere is distorted at different locations by its high winds and its strong tides!

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.

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redplanet44

7 years ago

New process allows 3-D printing of nanoscale metal structures

Synthesizing organic scaffolds that contain metal ions enables 3-D printing of metallic structures that are orders of magnitude smaller than previously possible

For the first time, it is possible to create complex nanoscale metal structures using 3-D printing, thanks to a new technique developed at Caltech.

The process, once scaled up, could be used in a wide variety of applications, from building tiny medical implants to creating 3-D logic circuits on computer chips to engineering ultralightweight aircraft components. It also opens the door to the creation of a new class of materials with unusual properties that are based on their internal structure. The technique is described in a study that will be published in Nature Communications on February 9.

In 3-D printing – also known as additive manufacturing – an object is built layer by layer, allowing for the creation of structures that would be impossible to manufacture by conventional subtractive methods such as etching or milling. Caltech materials scientist Julia Greer is a pioneer in the creation of ultratiny 3-D architectures built via additive manufacturing. For instance, she and her team have built 3-D lattices whose beams are just nanometers across – far too small to be seen with the naked eye. These materials exhibit unusual, often surprising properties; Greer’s team has created exceptionally lightweight ceramics that spring back to their original shape, spongelike, after being compressed.

Greer’s group 3-D prints structures out of a variety of materials, from ceramics to organic compounds. Metals, however, have been difficult to print, especially when trying to create structures with dimensions smaller than around 50 microns, or about half the width of a human hair.

Heavy metal is in our blood!

Anytime you don’t feel powerful, remember this:

Supergiant stars are beasts! Their life is a fight between gravity pushing in and heat pushing out. They fuse heavier and heavier elements in their core until they get to iron. They can’t fuse any more. Iron absorbs more energy than it returns, so gravity takes over. The star’s core collapses and the star dies in an explosive supernova that outshines its entire galaxy.

The heat of a supernova fuses new elements during the explosion, which are then spread out into space via the nebula remnant. Nebulae are the birthplaces of new stars and solar systems.

The iron in your blood came from one of the most powerful explosions in the universe.

Anytime You Don’t Feel Powerful, Remember This:

You have something in your blood that can kill stars and build solar systems.

Webb 101: 10 Facts about the James Webb Space Telescope

Did you know…?

1. Our upcoming James Webb Space Telescope will act like a powerful time machine – because it will capture light that’s been traveling across space for as long as 13.5 billion years, when the first stars and galaxies were formed out of the darkness of the early universe.

2. Webb will be able to see infrared light. This is light that is just outside the visible spectrum, and just outside of what we can see with our human eyes.

3. Webb’s unprecedented sensitivity to infrared light will help astronomers to compare the faintest, earliest galaxies to today’s grand spirals and ellipticals, helping us to understand how galaxies assemble over billions of years.

Hubble’s infrared look at the Horsehead Nebula. Credit: NASA/ESA/Hubble Heritage Team

4. Webb will be able to see right through and into massive clouds of dust that are opaque to visible-light observatories like the Hubble Space Telescope. Inside those clouds are where stars and planetary systems are born.

5. In addition to seeing things inside our own solar system, Webb will tell us more about the atmospheres of planets orbiting other stars, and perhaps even find the building blocks of life elsewhere in the universe.

Credit: Northrop Grumman

6. Webb will orbit the Sun a million miles away from Earth, at the place called the second Lagrange point. (L2 is four times further away than the moon!)

7. To preserve Webb’s heat sensitive vision, it has a ‘sunshield’ that’s the size of a tennis court; it gives the telescope the equivalent of SPF protection of 1 million! The sunshield also reduces the temperature between the hot and cold side of the spacecraft by almost 600 degrees Fahrenheit.

8. Webb’s 18-segment primary mirror is over 6 times bigger in area than Hubble’s and will be ~100x more powerful. (How big is it? 6.5 meters in diameter.)

9. Webb’s 18 primary mirror segments can each be individually adjusted to work as one massive mirror. They’re covered with a golf ball’s worth of gold, which optimizes them for reflecting infrared light (the coating is so thin that a human hair is 1,000 times thicker!).

Webb 101: 10 Facts About The James Webb Space Telescope

10. Webb is so sensitive, it could detect the heat signature of a bumblebee at the distance of the moon, and can see details the size of a US penny at the distance of about 40 km.

BONUS! Over 1,200 scientists, engineers and technicians from 14 countries (and more than 27 U.S. states) have taken part in designing and building Webb. The entire project is a joint mission between NASA and the European and Canadian Space Agencies. The telescope part of the observatory was assembled in the world’s largest cleanroom at our Goddard Space Flight Center in Maryland.

Webb is currently being tested at our Johnson Space Flight Center in Houston, TX.

Afterwards, the telescope will travel to Northrop Grumman to be mated with the spacecraft and undergo final testing. Once complete, Webb will be packed up and be transported via boat to its launch site in French Guiana, where a European Space Agency Ariane 5 rocket will take it into space.

Learn more about the James Webb Space Telescope HERE, or follow the mission on Facebook, Twitter and Instagram.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.

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redplanet44

6 years ago

Breakthrough in blending metals—precise control of multimetallic one-nanometer cluster formation achieved

Researchers in Japan have found a way to create innovative materials by blending metals with precision control. Their approach, based on a concept called atom hybridization, opens up an unexplored area of chemistry that could lead to the development of advanced functional materials.

Multimetallic clusters—typically composed of three or more metals—are garnering attention as they exhibit properties that cannot be attained by single-metal materials. If a variety of metal elements are freely blended, it is expected that as-yet-unknown substances are discovered and highly-functional materials are developed. So far, no one had reported the multimetallic clusters blended with more than four metal elements so far because of unfavorable separation of different metals. One idea to overcome this difficulty is miniaturization of cluster sizes to one-nanometer scale, which forces the different metals to be blended in a small space. However, there was no way to realize this idea.