Tag Archives: Junk

Our body clock is largely kept working by “junk DNA”

The so-called “junk” bits of our DNA is not, after all, quite junk. New research shows that these seemingly inactive genetic elements, micro RNAs (miRNAs), act as a genome-wide time-keeping mechanism, maintaining the function and accuracy of our body clocks. They also make you jet-lagged.

Image via Pixabay.

Until now, research into the origins of our circadian rhythm (body clock) focused on what are known as clock genes — these contain the data for proteins that keep the clock ticking. Judging by this rhythm, our body knows when it’s time to wake up or go to bed, when it’s time to eat, when it falls dark. It then prepares for each of these times, generally by releasing different hormones to prep your body up. Needless to say, this rhythm is a very important adaptation that allows organisms to sync in with their environment.

We’ve been studying its origins in the hope of developing new treatment options for diseases such as Alzheimer’s, cancer and diabetes, but progress has been slow. It may have been that we were looking in the wrong place all along, new research reports.

Clocks in unusual places

“We’ve seen how the function of these clock genes are really important in many different diseases,” said Steve Kay, Provost Professor of neurology, biomedical engineering, and quantitative computational biology at the Keck School of Medicine of the University of Southern California.

“But what we were blind to was a whole different funky kind of genes network that also is important for circadian regulation and this is the whole crazy world of what we call non-coding microRNA.”

Molecular circadian clocks exist in every cell in the body, the team reports. They are small bunches on non-coding nucleotides known as micro RNAS, which can affect the patterns of gene expression by preventing messenger RNA from being turned into proteins. In essence, their job is to stop the protein blueprints from being taken to the factory if it’s not the right time. Past research has hinted at this role of miRNAs, but determining which of the hundreds of such molecules in the genome actually influence the circadian rhythm was quite a challenge.

The team, led by Lili Zhou, a research associate in the Keck School’s Department of Neurology, worked with the Genomics Institute of the Novartis Research Foundation (GNF) in San Diego, which produces robots capable of high throughput experiments. Along with Zhou, they developed a new robot to test almost a thousand miRNAs individually. Each strand was transferred into a cell. These cells were engineered to glow on and off based on their internal clock, which allowed the team to monitor its function.

The next step was to inactivate certain miRNAs identified in the previous step in similar cells. This had an inverse effect on the cells’ behavior than activating the genes — suggesting that their activity is directly involved in maintaining the circadian rhythm, and the previous experiment wasn’t picking up on an unrelated mechanism.

“The collaboration with GNF made it possible for us to conduct the first cell-based, genome-wide screening approach to systematically identify which of the hundreds of miRNAs might be the ones modulating circadian rhythms,” said Zhou.

“Much to our surprise,” added Kay, “we discovered about 110 to 120 miRNAs that do this.”

As for their role on a greater level, the team also studied the physiological and behavioral impacts of miRNAs. They engineered mice with an inactivated miR 183/96/182 cluster, which interfered with their wheel-running behavior in the dark compared with control mice. Further examination of brain, retina, and lung tissue revealed different effects in every tissue — suggesting that the way miRNAs operate is different among tissues.

The findings, the team says, could present a solid launching board for new treatments or prevention avenues for specific diseases.

“In the brain we’re interested in connecting the clock to diseases like Alzheimer’s, in the lung we’re interested in connecting the clock to diseases like asthma,” said Kay.

“The next step I think for us to model disease states in animals and in cells and look at how these microRNAs are functioning in those disease states.”

The paper “A genome-wide microRNA screen identifies the microRNA-183/96/182 cluster as a modulator of circadian rhythms” has been published in the journal Proceedings of the National Academy of Sciences.

Ricky Arnold, RemoveDEBRIS.

The International Space Station just launched a harpoon-toting satellite to keep it safe from space junk

The International Space Station (ISS) has just deployed its own robotic groundskeeper — christened RemoveDEBRIS, the small cubesat will work to clean Earth’s orbit of wreckage and debris.

Debris.

Space debris plot.
Image credits NASA.

Fans of Star Trek: The Next Generation might get flashbacks of the Borg cube upon seeing the little satellite just launched by the ISS. But fret not, fans of old-timey sci-fi; although it carries a harpoon, this craft comes in peace. RemoveDEBRIS — the result of a collaboration between Airbus, Surrey Satellite Technology, NanoRacks and a slew of other companies — will whizz about the ISS, spearing debris left and right to tidy up our orbit.

Cube-at-arms

We’re not the tidiest species around if we’re being honest. We’ve actually managed to (somewhat-impressively) litter all the way out to space. It’s already full of decommissioned satellites, rocket wreckage, shards of solar panels, and flakes of paint. And we are still blasting stuff up there, making it increasingly crowded.

Space may sound like the ultimate rug to brush your mess under — but it’s not. At the speeds involved, even the flakes of paint currently orbiting Earth are massive threats. As Einstein quoth, “E=mc2“, and although these flakes are light (small values for ‘m’), they go very very fast, meaning they act like hypersonic projectiles with a lot of force behind them (‘E’). Luckily, we’ve yet to see a catastrophic collision between one our craft and such debris.

Not ones to bet on luck for long, however, NASA sent RemoveDEBRIS to — you’ll never guess — remove some of this debris. The cube-shaped satellite was recently launched towards the ISS aboard a SpaceX Dragon capsule. In its first test since arriving, the 100-kilogram (220 pounds) cubesat was just released from the station via the robotic arm Canadarm2, the agency writes. Researchers at the University of Surrey, England, have successfully established contact with the satellite after release. Surprisingly, the satellite is one of the biggest payloads the ISS ever deployed.

Ricky Arnold, RemoveDEBRIS.

Ricky Arnold of NASA prepares the RemoveDEBRIS satellite for deployment aboard the International Space Station.
Image credits NASA.

Over the next couple of months, engineers will monitor RemoveDEBRIS and run tests to ensure everything is functioning correctly. However, NASA doesn’t expect to break out the satellite’s harpoon until later this year. Beyond this sharp implement, RemoveDEBRIS also carries a net to catch junk with, and a large sail meant for braking or eventual deorbiting — and both instruments need to be tested separately. The current timetable for these tests, as listed by the University of Surrey, is:

  • A debris-catching net experiment, developed at Airbus’ site in Bremen, Germany, will be conducted in October. The main RemoveDebris spacecraft will release a small cubesat and let it drift away to a distance of about 5 to 7 m (16 to 23 feet). Then, the main spacecraft will eject the net in an attempt to capture it.
  • In December, RemoveDEBRIS will test vision-based navigation technology developed by Airbus in Toulouse, France. The technology will use a set of 2D cameras and a 3D lidar technology to track the second cubesat as it floats away from the main satellite.
  • In February 2019, the last of Airbus’ three experiments will take place. RemoveDEBRIS will fire a pen-size harpoon into a panel that will deploy from the main spacecraft attached to a boom.
  • Sometime during March 2019, RemoveDEBRIS spacecraft will deploy a drag sail, developed by the Surrey Space Centre, which will speed up the satellite’s deorbiting process.

The drag sail is especially important, according to the agency. Via its use, the cubesat will avoid becoming the irony of becoming debris itself — the sail will slow down RemoveDEBRIS enough for it to fall back to Earth.

Ideally, RemoveDEBRIS will only be the first in a series of harpoon-wielding, net-totting janitor satellites. According to the Space Surveillance Network (SSN), there are over 23,000 pieces of debris larger than a softball, and there are likely too many tiny bits for us to reliably track. It’s such a huge problem that researchers are even considering giving the ISS its own battery of laser weapons, just to keep it safe.

International Space Station.

New, powerful laser system proposed for the International Space Station’s defense

Space is a dirty place, so the ISS needs some lasers to blast it clean, researchers propose.

International Space Station.

The International Space Station.
Image credits NASA.

If you’re a fan of Sci-Fi, we’re in luck — an international group of scientists wants to see our most burning desire made real. They propose to install a laser defense system aboard the International Space Station (ISS) to blast at litter in the near-Earth orbit.

My kinda cleaning

The idea of ‘arming’ the ISS with laser batteries isn’t new but we’re just now getting to a place where we can develop systems compact and reliable enough to be practical aboard the station. To jump-start development, an international team of researchers from France, Italy, Japan, and Russia is pooling their efforts, according to Boris Shustov, member of the Russian Academy of Sciences (RAS).

The system they’re considering would consist of orbital lasers aboard the ISS. It should be effective against the most common type of space debris around Earth — pieces that only measure a few centimeters.

The idea was first proposed by Japanese researchers back in 2015. The original project draft envisioned lasers using 10,000 optical fiber channels and would draw all of the ISS’s electrical output to work at full capacity, according to the team. That, understandably, isn’t a particularly attractive defensive system. The new project aims to provide the same power output by using 100 “thin rods” in lieu of the optical fibers. This would reduce the overall energy drain to only 5% of the ISS’s output — a twenty-fold decrease.

This version of the laser system would allow the ISS to fire laser bursts for 10 seconds, up to a range of 10 kilometers (6.2 miles), with a recharge time of 200 seconds, according to Russian media. The whole system would weigh about 500 kilograms (1,100 pounds).

It’s a small price to pay, considering the benefits such a system would provide. The ISS still has to make routine adjustments to its orbit to avoid collisions with pieces of man-made junk. These bits are parts of former rockets or spacecraft that have been broken up into small pieces through mutual collisions over the years, or from the effects of space radiation.

They’re quite small, going very fast, and can have disastrous consequences to the ISS’s structural integrity should they hit. There’s also a lot of them. NASA is currently tracking about 17,000 pieces about the size of your fist and half a million pieces roughly the size of a marble. According to their estimates, there are over 200 million pieces over one millimeter in size still floating in Earth’s orbit at speeds in excess of 17,500 mph (over 28.100 km/h).

An impact with any single one of those fragments could jeopardize the ISS and its crew.