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The Island of Discussion, Glencoe, Scotland. It was a place to settle disputes. A place to resolve differences. Officially named Eilean a’ Chomhraidh, the Island of Discussion is small and alone. This island has served a noble purpose for many, many years.  Over 1,500 years or so. When clansman had a disagreement, this is the place they went to work it out. The rules were simple. When there were quarrels or arguments, the feuding parties where taken out to the island and left alone. Left there. With whiskey, cheese, and oat cakes. And they didn’t leave the island until the dispute was settled. The result, in over 1,500 years, only 1 recorded murder in the area.

(Fact Source)

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Autoimmune diseases — such as type 1 diabetes, rheumatoid arthritis or multiple sclerosis — all have one thing in common: they occur when the body’s own immune system attacks itself. One culprit is effector T cells, immune cells that are supposed to stimulate inflammation and help get rid of cells infected with viruses. Their cousins, regulatory T cells (Tregs), act like a brake, keeping some of those effector T cells in check. Tregs inhibit inflammation and prevent autoimmune diseases.

But sometimes, Tregs don’t do a very good job, the immune system gets out of hand and healthy cells and tissues suffer as collateral damage.

John T. Chang, MD, associate professor at UC San Diego School of Medicine, and his research team study T cells and how they develop and function. They recently discovered that a family of molecules called integrins helps Tregs to function properly — in other words, integrins can help apply the brake on pro-inflammatory T cells.

In this installment of JUST THE FAQs, Chang discusses their latest findings, published June 15 in the Journal of Immunology, and their potential implications for treating autoimmune diseases.

A regulatory T cell (Treg) is shown in green interacting with a CD4 T cell on the bottom and virus on the left. Source: Wikimedia

What are integrins? Integrins are proteins embedded in the membranes of most cells. They’re most famous for their adhesive properties — integrins help cells stick to one another and their surrounding tissues — but they also play roles in cellular communication, molecular signaling and trafficking.

What’s new about integrins? We wondered whether the activation state of integrins is important for Treg function. So we dove in and looked at this question in a rigorous way. We did that by deleting a gene in mice that encodes talin, an activator of beta-integrins. And we did that specifically in Tregs, not other cell types.

Then we looked at what happened to the mice. Those lacking talin (and therefore lacking activated beta-integrins in their Tregs) developed spontaneous autoimmunity. We took this a step further and looked at mice that had a mutated version of talin that specifically could not activate integrins. These mice also developed spontaneous autoimmunity. We also looked at the Tregs in these mice and found that they’re defective in multiple ways — the pattern of genes they express is dramatically altered and they’re no longer able to suppress inflammation.

That told us that integrin activation is crucial for Treg function.

What surprised you? We were surprised at how severe the disease was in the mice that lacked talin in their Tregs. Even shortly after birth, they clearly looked sick. They had skin disease, didn’t gain weight and their fur didn’t grow well. They developed spontaneous, lethal disease within two to three months.

Why is this important? Since our findings implied that integrin activation is needed for Tregs to function properly, it made us wonder … can you manipulate that pathway to boost Treg function? That might be useful in a variety of autoimmune diseases in which Tregs aren’t working properly and other T cells are allowed to run amok.  

Integrins toggle between activated and inactivated states, and there are antibodies that lock the integrins in activated conformations. So we treated talin-deficient mice with one of these antibodies and found that it improved their inflammation.

We think manipulating integrins to boost Tregs could be a new approach to treating autoimmune diseases.

What’s next? Next we want to test the integrin-activating antibodies on human cells and in animal models of autoimmunity to see if they can reverse or prevent disease. There are good mouse models for many autoimmune diseases, including type 1 diabetes, inflammatory bowel disease, rheumatoid arthritis and multiple sclerosis. They’re not perfect replacements for humans, of course, but it’s a starting point to test our hypotheses and unravel the mechanisms at play.

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And solar panels can literally be built into roofs of buildings and in empty areas like deserts. The sun strikes the Earth with the same amount of energy in an hour that our civilization uses in a year.

But yeah, it would be impossible for us to ever have enough energy from clean sources.

High-resolution images of Pluto taken by NASA’s New Horizons spacecraft.

The plains on Pluto’s surface are composed of more than 98 percent nitrogen ice, with traces of methane and carbon monoxide. Nitrogen and carbon monoxide are most abundant on the anti-Charon face of Pluto (around 180° longitude, where Tombaugh Regio’s western lobe, Sputnik Planitia, is located), whereas methane is most abundant near 300° east. The mountains are made of water ice. Pluto’s surface is quite varied, with large differences in both brightness and color. Pluto is one of the most contrastive bodies in the Solar System, with as much contrast as Saturn’s moon Iapetus. The color varies from charcoal black, to dark orange and white. Pluto’s color is more similar to that of Io with slightly more orange and significantly less red than Mars. Notable geographical features include Tombaugh Regio, or the “Heart” (a large bright area on the side opposite Charon), Cthulhu Macula, or the “Whale” (a large dark area on the trailing hemisphere), and the “Brass Knuckles” (a series of equatorial dark areas on the leading hemisphere). Sputnik Planitia, the western lobe of the “Heart”, is a 1,000 km-wide basin of frozen nitrogen and carbon monoxide ices, divided into polygonal cells, which are interpreted as convection cells that carry floating blocks of water ice crust and sublimation pits towards their margins; there are obvious signs of glacial flows both into and out of the basin. It has no craters that were visible to New Horizons, indicating that its surface is less than 10 million years old.

Earth is a place dominated by water, mainly oceans. It’s also a place our researchers study to understand life. Trillions of gallons of water flow freely across the surface of our blue-green planet. Ocean’s vibrant ecosystems impact our lives in many ways. 

In celebration of World Oceans Day, here are a few things you might not know about these complex waterways.

1. Why is the ocean blue? 

The way light is absorbed and scattered throughout the ocean determines which colors it takes on. Red, orange, yellow,and green light are absorbed quickly beneath the surface, leaving blue light to be scattered and reflected back. This causes us to see various blue and violet hues.

2. Want a good fishing spot? 

Follow the phytoplankton! These small plant-like organisms are the beginning of the food web for most of the ocean. As phytoplankton grow and multiply, they are eaten by zooplankton, small fish and other animals. Larger animals then eat the smaller ones. The fishing industry identifies good spots by using ocean color images to locate areas rich in phytoplankton. Phytoplankton, as revealed by ocean color, frequently show scientists where ocean currents provide nutrients for plant growth.

3. The ocean is many colors. 

When we look at the ocean from space, we see many different shades of blue. Using instruments that are more sensitive than the human eye, we can measure carefully the fantastic array of colors of the ocean. Different colors may reveal the presence and amount of phytoplankton, sediments and dissolved organic matter.

4. The ocean can be a dark place. 

About 70 percent of the planet is ocean, with an average depth of more than 12,400 feet. Given that light doesn’t penetrate much deeper than 330 feet below the water’s surface (in the clearest water), most of our planet is in a perpetual state of darkness. Although dark, this part of the ocean still supports many forms of life, some of which are fed by sinking phytoplankton. 

5. We study all aspects of ocean life. 

Instruments on satellites in space, hundreds of kilometers above us, can measure many things about the sea: surface winds, sea surface temperature, water color, wave height, and height of the ocean surface.

6. In a gallon of average sea water, there is about ½ cup of salt. 

The amount of salt varies depending on location. The Atlantic Ocean is saltier than the Pacific Ocean, for instance. Most of the salt in the ocean is the same kind of salt we put on our food: sodium chloride.

7. A single drop of sea water is teeming with life.  

It will most likely have millions (yes, millions!) of bacteria and viruses, thousands of phytoplankton cells, and even some fish eggs, baby crabs, and small worms. 

8. Where does Earth store freshwater? 

Just 3.5 percent of Earth’s water is fresh—that is, with few salts in it. You can find Earth’s freshwater in our lakes, rivers, and streams, but don’t forget groundwater and glaciers. Over 68 percent of Earth’s freshwater is locked up in ice and glaciers. And another 30 percent is in groundwater. 

9. Phytoplankton are the “lungs of the ocean”.

Just like forests are considered the “lungs of the earth”, phytoplankton is known for providing the same service in the ocean! They consume carbon dioxide, dissolved in the sunlit portion of the ocean, and produce about half of the world’s oxygen. 

Want to learn more about how we study the ocean? Follow @NASAEarth on twitter.

A black hole is a region of spacetime exhibiting such strong gravitational effects that nothing—not even particles and electromagnetic radiation such as light—can escape from inside it. The theory of general relativity predicts that a sufficiently compact mass can deform spacetime to form a black hole. The boundary of the region from which no escape is possible is called the event horizon. Although the event horizon has an enormous effect on the fate and circumstances of an object crossing it, no locally detectable features appear to be observed. In many ways a black hole acts like an ideal black body, as it reflects no light.  

The idea of a body so massive that even light could not escape was briefly proposed by astronomical pioneer and English clergyman John Michell in a letter published in November 1784. Michell’s simplistic calculations assumed that such a body might have the same density as the Sun, and concluded that such a body would form when a star’s diameter exceeds the Sun’s by a factor of 500, and the surface escape velocity exceeds the usual speed of light.

At the center of a black hole, as described by general relativity, lies a gravitational singularity, a region where the spacetime curvature becomes infinite. For a non-rotating black hole, this region takes the shape of a single point and for a rotating black hole, it is smeared out to form a ring singularity that lies in the plane of rotation. In both cases, the singular region has zero volume. It can also be shown that the singular region contains all the mass of the black hole solution. The singular region can thus be thought of as having infinite density. 

How Do Black Holes Form?

Scientists think the smallest black holes formed when the universe began.

Stellar black holes are made when the center of a very big star falls in upon itself, or collapses. When this happens, it causes a supernova. A supernova is an exploding star that blasts part of the star into space.

Scientists think supermassive black holes were made at the same time as the galaxy they are in.

Supermassive black holes, which can have a mass equivalent to billions of suns, likely exist in the centers of most galaxies, including our own galaxy, the Milky Way. We don’t know exactly how supermassive black holes form, but it’s likely that they’re a byproduct of galaxy formation. Because of their location in the centers of galaxies, close to many tightly packed stars and gas clouds, supermassive black holes continue to grow on a steady diet of matter.

If Black Holes Are “Black,” How Do Scientists Know They Are There?

A black hole can not be seen because strong gravity pulls all of the light into the middle of the black hole. But scientists can see how the strong gravity affects the stars and gas around the black hole. 

Scientists can study stars to find out if they are flying around, or orbiting, a black hole.

When a black hole and a star are close together, high-energy light is made. This kind of light can not be seen with human eyes. Scientists use satellites and telescopes in space to see the high-energy light.

On 11 February 2016, the LIGO collaboration announced the first observation of gravitational waves; because these waves were generated from a black hole merger it was the first ever direct detection of a binary black hole merger. On 15 June 2016, a second detection of a gravitational wave event from colliding black holes was announced. 

Simulation of gravitational lensing by a black hole, which distorts the image of a galaxy in the background 

Animated simulation of gravitational lensing caused by a black hole going past a background galaxy. A secondary image of the galaxy can be seen within the black hole Einstein ring on the opposite direction of that of the galaxy. The secondary image grows (remaining within the Einstein ring) as the primary image approaches the black hole. The surface brightness of the two images remains constant, but their angular size varies, hence producing an amplification of the galaxy luminosity as seen from a distant observer. The maximum amplification occurs when the background galaxy (or in the present case a bright part of it) is exactly behind the black hole.

Could a Black Hole Destroy Earth?

Black holes do not go around in space eating stars, moons and planets. Earth will not fall into a black hole because no black hole is close enough to the solar system for Earth to do that.

Even if a black hole the same mass as the sun were to take the place of the sun, Earth still would not fall in. The black hole would have the same gravity as the sun. Earth and the other planets would orbit the black hole as they orbit the sun now.

The sun will never turn into a black hole. The sun is not a big enough star to make a black hole.

More posts about black holes