The top three news stories of the week, as chosen by our resident students. This week’s top stories include the discovery of a new exoplanet, rats overcoming their fear response and a successful transplant of lab-grown lungs.
By Gintare Bucaite
A planet without a home
There is a particularly odd planet wandering the Milky Way and it’s just 20 light-years away from the Sun. It’s massive, it’s hot, has a magnetic field 4 million times stronger than Earth, produces spectacular auroras, and it’s not orbiting any star.
This bizarre planet, beautifully named SIMP J01365663+0933473 (let’s just call it SIMP here), was observed using National Science Foundation’s Karl G. Jansky Very Large Array (VLA) and was published in the Astrophysical Journal. “This object is right at the boundary between a planet and a brown dwarf, or ‘failed star,’ and is giving us some surprises that can potentially help us understand magnetic processes on both stars and planets,” explained Melodie Kao, who led this study as a graduate student at Caltech.
Although massive, SIMP is just about small enough to be considered a planet – it’s around 12.7 times the mass and 1.2 times the radius of Jupiter, while Jupiter itself has a diameter that’s 11.2 times larger than Earth. SIMP is not only a mammoth planet, but a sweaty one too – the surface temperature is around 825 °C, so not too far off the temperature in London this summer. For comparison, Venus, the hottest planet in the Solar system is merely 470 °C hot on average. However, Venus gets most of its heat from the Sun, while the nomadic SIMP must have this leftover heat from its formation around 200 million years ago. SIMP has an incredibly strong magnetic field and this gives fascinating light shows, and the charged particles, which lead to the auroras, probably come not from a star in the form of solar wind, like in Earth’s case, but more likely from a moon, just like in Jupiter’s case. So, SIMP may have a moon too!
The scientists say that planets like SIMP are exciting and informative too. Understanding its magnetic dynamo mechanisms could help to understand how they can operate in planets beyond our Solar systems, and possibly be applicable not only in brown dwarfs but in gas giants and terrestrial planets too.
Read more about this finding here.
Fear can be overcome, and scientists at RIKEN Centre for Brain Science have discovered a circuit in the brain that is required for unlearning fear. Published in Nature Communications, the study describes how dopamine plays a role in fear extinction learning to ensure that rats stop being afraid when there is nothing to be afraid of anymore.
Understanding the neurobiology of moving on from fearful experiences is particularly important for disorders such as post-traumatic stress disorders, and now there is evidence that dopamine neurons originating in the area called ventral tegmental area (VTA) are involved in extinguishing fear responses.
During the experiments, rats were conditioned to associate a specific sound (think of it like a soundtrack in horror movies when you know something horrifying is about to happen) with aversive experience (mild footshock for rats). After the conditioning step, scientists began the extinction process. Now, when they played the sound without the shock multiple times, rats stopped being afraid of the sound. However, if the rats had their VTA-dopamine neurons silenced so that they would not be activated during the auditory stimulus, rats still showed the fear response, suggesting dopamine activity is necessary for reducing fear responses.
Scientists behind the study hope that these findings will eventually have relevance for the treatment of human anxiety disorders, improving current therapies by providing a molecular mechanism behind the extinction of fear response.
Find more information about this study here.
Piggy gets a new lung
In the UK, there are more than 7,500 people waiting for an organ transplant, including 230 patients waiting for a lung transplant. The numbers are even higher in the countries like US – where more than 1,400 people are waiting for a lung transplant, and there simply aren’t enough donor lungs to meet the demand. Hopefully, all these patients may take a breath of relief in the future with brand new lab-grown lungs.
A research team from University of Texas Medical Branch have reported their most recent progress on the creation of lab-grown lungs in Science Translational Medicine this week. They have successfully produced and transplanted bioengineered lungs in a clinically relevant pig model (we have lots of anatomical and physiological similarities with pigs!). For a scaffold for their bioengineered lung, scientists have used a pig lung that has been stripped away from all of the cells and blood, leaving just the ‘skeleton’ of the lung. Then, they placed the scaffold lung in the special tank which contained justthe right mix of nutrients. The recipient pig’s own lung cells were then added to the scaffold and allowed to grow for 30 days. When the lungs were transplanted into the recipient pigs, it only took two weeks for the blood vessel network to form, and during the two months follow up, no signs of rejection were observed.
If everything goes well, we could be just five to ten years away from creating these bioengineered lungs for human patients, especially for people with life-threatening conditions with no other treatment options. Eventually, bioengineered lungs could replace donor lungs altogether, as they are made using recipients own cells, so the likelihood of rejection is much lower, not to mention that they can be lab grown – so no more organ shortages.
Read more about this interesting story here.