Stem Cells & Self Distilling Vodka
In this NewsFlash, how induced stem cells help us to understand Alzheimer's disease, while embryonic stem cells can help restore patients' sight. Plus, why a graphene oxide filter can make self distilling vodka, how magic mushrooms affect the brain, and the magnetic soap that cleans the parts other detergents can't reach!
In this episode
00:24 - Stem cells provide Alzheimer's clues
Stem cells provide Alzheimer's clues
One of the biggest problems with studying brain diseases such as Alzheimer's is the difficulty of getting samples of living brain cells from patients, and finding good model systems that be studied easily in the lab. There are some mouse models of Alzheimer's which have been very useful, but these don't copy all the symptoms and changes that are seen in the human disease.
Most studies of Alzheimer's disease using human tissue have been done using samples from people with a rare inherited forms of Alzheimer's, but actually the vast majority of cases are randomly-occurring, or sporadic, forms of the disease. There's also been a bit of work done using nerve cells from human foetuses, but there are ethical and technical issues with using this kind of tissue.
Now researchers led by Mason Israel and Lawrence Goldstein from the Howard Hughes Medical Institute in California have published a paper in the journal Nature, revealing a way to generate stem cells from Alzheimer's patients, which can then be grown indefinitely in the lab.
The researchers started by taking small samples of skin from two patients with an inherited form of Alzheimer's disease, two patients with randomly occurring, sporadic Alzheimer's, and two people without disease. Then the scientists separated out specific cells called fibroblasts from each skin sample, which can be grown in dishes in the lab for a limited time.
Next, they used a relatively new and very exciting technique, using a special virus known as a retrovirus to deliver a particular suite of genes into the fibroblasts, which transformed them into immortal stem cells. These cells are known as pluripotent stem cells, because they can be converted into several different types of cell.
Next, the researchers grew these pluripotent stem cells under certain conditions that cause them to grow into nerve cells, or neurons - the kind of cells that are affected in Alzheimer's. Studying these cells in depth showed that the neurons grown from samples taken from patients with hereditary Alzheimer's had high levels of amyloid - a protein that makes the plaques that are the main characteristic of the disease. They also found higher levels of a protein called phospho-Tau, which makes knotty tangles in the brain of patients.
Intriguingly, they also found higher levels of amyloid and phospho-Tau in neurones made from cells from one of the patients with sporadic Alzheimer's, even though the patient's original fibroblasts didn't show increased levels of the molecules. This tells us that there must be some kind of gene variations or faults in the patient's genome that are causing the disease, although at the moment the identity of these genes is unknown, so using this kind of technique to study cells from many more patients with sporadic Alzheimer's could provide really important clues to why some people develop the disease.
With experiments like this, there's always a risk that manipulating the cells in the lab could introduce unexpected gene faults that confuse the results. At the moment it's not clear whether that's happened at all here, and only will time will tell exactly how effective these pluripotent cells are a model for studying Alzheimer's in the lab. But for now it's certainly an important tool that researchers can take forward, and should hopefully provide more clues as to how Alzheimer's develops, and how it might be treated or prevented in the future.
04:10 - Self Distilling Vodka
Self Distilling Vodka
Graphene is probably the material of the moment, it is made up of carbon atoms bonded to one another in a honeycomb pattern forming extremely strong sheets. These sheets can be stable at just one atom thick, and have very exciting electrical properties, but are also remarkably impermeable to other atoms...
Members of Professor Sir Andre Geim's group at the University of Manchester, where graphene was first identified, were investigating the permiability of a closely related material called graphene oxide. This is graphene which has been reacted with a strong oxidising agent, making it more soluble and easier to deal with.
They created membranes made up of small pieces of graphene oxide which pile up like bricks to form an interlocked structure, and then tested how gas-proof they were by using the film as a lid for a container full of various gases.
They found that despite being 500 times thinner than a human hair, it completely stopped Hydrogen, Nitrogen and Argon from escaping, to the limits of their measurements. It even stopped Helium which, being a tiny single atom will escape from party balloons very quickly, and can even diffuse out through a millimetre of glass.
They then tried various liquids, and found similar behaviour for ethanol, hexane, acetone, decane and propanol vapour, but when they tried normal water it behaved as if the membrane wasn't there, escaping at least a hundred thousand times faster than any of the other materials. They think the water is forming a layer one molecule thick between the layers of graphene, blocking the route for everything else, but if it dries out, this gap shrinks and seals up.
To make use of this behaviour they put some vodka in the container, and left it for a few days. Normally ethanol evaporates faster than water so vodka gets weaker over time, but with their membrane, which blocked the ethanol, the vodka got stronger and stronger.
This is extremely interesting behaviour, as seperating water from other solvents is a huge part of many chemical processes. This is normally done by distillation, which takes a large amount of energy, and the process has to be repeated many times. Ethanol cannot be concentrated to more than 96% without involving poisonous solvents to remove the water, so this material has a huge potential.
07:12 - Embryonic stem cell treatment improves patients' vision
Embryonic stem cell treatment improves patients' vision
In two blind-registered American patients, an injection of retinal pigment epithelium made from human embryonic stem cells has partially restored vision.
A case report in the Lancet medical journal describes the procedure carried out on the two volunteers who were both suffering with degenerative conditions (Stargardts Macular Dystrophy and age-related macular degeneration) that cause the cells in the retina to die off, leading to progressive sight loss and, as in these patients, eventually blindness.
This occurs primarily because a specialised cell layer called the retinal pigment epithelium, which nourishes the light-sensitive rod and cone photoreceptors in the eye, breaks down. Robbed of these supporting cells, the photoreceptors eventually follow suit and degenerate.
But if the retinal pigment epithelium can be replaced, it should be possible to rescue the rods and cones before they succumb, preventing vision loss.
But making new pigment epithelium is not trivial and is most easily achieved using embryonic stem cells which can be pursuaded to turn into the correct cell types by culturing them under the right conditions.
No one knows, however, how effective, or safe, cells produced in this way might be, although tests in laboratory animals genetically engineered to develop similar sight-loss syndromes to humans have been very encouraging.
To address this question, a US team of doctors and researchers, including Massachusetts-based stem cell scientist Robert Lanza from the company Advanced Cell Technology, used human embryonic stem cells to produce fifty thousand new retinal pigment epithelial cells that were injected into one of each of the patients' eyes.
Four months later, examination of the injected eyes showed improved pigmentation visible in their retinae, suggesting that the cells had remained viable, and both patients had objective improvements in their vision. One patient was even able to count the number of fingers held up by the examiner having previously been able to distinguish only gross movements of a hand being waved at them.
Critically, neither patient showed any ill effects as a result of the procedure nor any reduction in visual function, although both were given immunosuppression to prevent rejection of the foreign stem-cell derived tissue.For how long, if at all, they will need this though, isn't known.
According to Robert Lanza, "Despite the progressive nature of these conditions, the vision of both patients appears to have improved after transplantation of the cells. This is particularly important, since the ultimate goal of this therapy will be to treat patients earlier in the course of the disease where more significant results might be expected...
11:15 - The Magnetic Moon
The Magnetic Moon
Erin Shea, MIT
Chris - When Neil Armstrong and Buzz Aldrin brought back the first samples of Moon rock in 1969, scientists were surprised to see tell-tale signs in material that the Moon had once had a magnetic field - a bit like the one that we have on Earth today. They thought that this magnetic field was created by geological processes that were occurring while the Moon was still hot from its birth, but that these had stopped once it had cooled down. Now though, another look at one of those 1969 samples has revealed something very unexpected. Erin Shea from MIT made the discovery. She is with us now. Hello, Erin.
Erin - Hello.
Chris - So what is it you found?
Erin - What I found was that 3.7 billion years ago, the Moon had a very strong, stable and long-lived magnetic field - like you said, similar to what the Earth has today.
Chris - If we wind back through the Moon's history, we think it's about the same age as the Earth - give or take - and it was formed by some catastrophic collision between Earth and an Earth-sized planet that then ejected all this material into space. So, is the Moon therefore effectively a mini Earth in orbit around the Earth?
Erin - In a lot of senses, the Moon and the Earth have a lot in common. They both have these metallic cores. On the Earth, thankfully, it's still going strong and producing our magnetic field. On the Moon, it seems like it died out several billion years ago.
Chris - But grossly, the mechanism that produces the magnetic field, we think would probably be similar, because the Moon has effectively spawned from the Earth.
Erin - Initially, we thought that if the Moon ever did have a magnetic field caused by a dynamo, which is what generates the magnetic field on the Earth, that dynamo would have the same power source on the Moon as it did on the Earth. What our study has just shown though is that the dynamo on the Moon lasted far longer than we would've expected it to if it had the same power source. On the Earth, the dynamo is driven by cooling. Basically, as the metal cools down, it convects the metallic core and that generates a magnetic field through some complicated physics. On the Moon though, we would've expected the Moon to cool off long ago, 4.2 billion years ago approximately. So seeing evidence for a magnetic field 2.7 billion years ago really kind of puts the alarm bells out that something other than cooling must've generated the moon's dynamo.
Chris - There's no way that you could've miscalculated or - I don't mean you, personally, but the scientific community could've miscalculated the rate of cooling for the Moon and that in fact, it is the same processes we have on Earth, it just took longer for the moon to cool down and therefore it kept its dynamo for longer?
Erin - Well, as a scientist, you can never say never, but I think it's rather unlikely that we misjudged this calculation. We know how much heat producing radioactive elements the Moon has, we know how big the Moon is, and so, from there, we can actually do this calculation. So probably not, but I would never cross that completely off the list.
Chris - So how did you actually do the study? You got your hands on a piece of material that Buzz Aldrin and Neil Armstrong brought back with them from 1969. I bet they don't come along every day.
Erin - No, it was like a dream. You apply to NASA and tell them what you're going to do with the sample and then they allocate you a given amount. We got one gram of lunar sample 1OO20, and we cut this into small pieces and measured the magnetic field on each of those pieces. We knew their orientation relative to each other, which is important for the measurements that we were doing.
Chris - So you can tell that there's a magnetic field written into that rock. How did it get there then?
Erin - There are lots of ways that rocks can acquire magnetic fields. On the Earth, when lava erupts, it can acquire a magnetic field from the Earth's magnetic field because you know, that's the reason that our compasses work. Then that rock could get hit by lightning and then it would get another magnetic field. On the Moon, there's a whole different set of sources. So, we have possibilities that lava was erupted onto the surface of the Moon and it cooled down in the presence of a magnetic field generated by a dynamo, and that would produce one set of characteristics. Another set of characteristics would be produced if there was a big impact and a magnetic field was produced by that impact. When we picked that sample up, it spent about 3 days riding back to the Earth on a spacecraft with DC current which also generates a magnetic field. It then spent 4 years sitting on the surface of the Earth in the presence of the Earth's magnetic field. There are all these sources and then lots and lots of different things in addition to that, that could've given this rock the magnetic field, and what we've shown is that this sample actually erupted as a magma. It was hot and then as it cooled down, it locked in a magnetisation that it seems was from a lunar dynamo, which is awesome.
Chris - So it's a time capsule effectively tracing a snapshot in time of the Moon's early history and recording the existence of this magnetic field a long while after we would've expected it to have gone away. Can you speculate for us as to how that came along? How did it come about? What could've caused this?
Erin - What could've caused this dynamo on the Moon? Obviously, we just talked about cooling and you're right, we don't know for sure. But we're pretty sure that the Moon would've been cooled by 3.7 billion years ago. There were two papers written and published in Nature in December that talked about different ways that you could've generated a lunar core dynamo. One of which was that the Earth of mechanically mixed the lunar core, the gravity of the Earth forced that around. This is really neat to think about because 3.7 billion years ago, the Moon was actually much closer to the Earth, so would've had a much bigger effect. The other paper was about large impacts, because when you look at the Moon today, you can tell that it's experienced a pretty rough history. There are lots of craters on the surface and what these people hypothesise is that maybe large impacts served to stir that lunar core and generate a dynamo.
Chris - And finally, does it have any implications for the Earth? It's one thing to worry about the moon where no one lives, but we live and die by our magnetic field. What about life on Earth? Does it tell us anything about the magnetic field here?
Erin - What it might tell us is, what does a magnetic field look like when it dies off? That's something it could tell us. And then also, what started this on the Earth? What was the Earth's early history like because if the Moon is full of craters then the Earth must've been bombarded with craters too. And so, what effect would that have had on the Earth's magnetic field and its early history?
18:24 - Mapping a Mushroom Trip, Speedy genes and Magnetic Soap!
Mapping a Mushroom Trip, Speedy genes and Magnetic Soap!
Robin Carhart-Harris, Imperial College London; Emmeline Hill, University College Dublin; Julian Eastoe, University of Bristol; Coren Apicella, Harvard Medical School.
Mapping a Mushroom Trip
How hallucinogenic drugs, such as magic mushrooms, affect the brain has been mapped in humans for the first time.
Using an fMRI scanner,, researchers watched how the brains of 30 volunteers responded to doses of psilocybin - the active ingredient of magic mushrooms.
The drug suppressed the activity of certain 'hub' regions of the brain that control how information flows between different brain regions. Areas known to control mood were also affected..
Robin Carhart-Harris, from Imperial College,
led the work.
Robin - The surprising result was that we only saw decreases in brain activity. We didn't actually see any increases anywhere in the brain. So the larger the drops in brain activity, the more intense the psychedelic effects of the drug. And then that they were in regions associated with the sense of self and also regions that's over active in depression because people are very self-conscious and self-critical in depression. The implication then is that the drug may be effective in treating patients with depression.
---'Speed Gene' unearthed in modern racehorsesThe
gene for speed in modern racehorses has been traced back toa single Mare that lived 300 years ago.
Since then, selective breeding for speed and stamina has led to a very high prevalence of a favourable "C-variant" of a gene called myostatin, which gives thoroughbred racehorses a sprinting boost.
Analysing the DNA of 593 horses from both Eurasian and north-American regions, Emmeline Hill from University College Dublin discovered where this speed gene came from in the first place and how it has spread.
Emmeline - The speed gene proliferation in the population is a result of the success of a horse called Northern Dancer. But also, the study shows how very quickly, economically valuable alleles can move within a population. This demonstrates that the power that breeders have to shape the diversity of the variation within their own populations and to be able to very quickly - with the knowledge of the genetic types of their horses - shape and develop a population of horses of the type that they want.
Attracting you with Magnetic Soap
The World's first
magnetic soap has been developed by scientists at the University of Bristol.
By combining iron-rich salts with the water-soluble component of soap, Julian Eastoe's team created soap particles with metallic centres meaning the soap can be controlled with a magnetic field.
Julian - There are various applications you can imagine. One which is quite obvious is the possibility to use magnets and these soaps to recover oil in oil spills for example. There are smaller scale applications. You can imagine trying to clean components of a machine or engine for example. Normal soaps could never get in to the nooks and crannies, but it now becomes possible using magnets to guide the soapy solutions into the parts which other soaps cannot reach.
---Hunter-Gatherer Social Networks
Social networks were crucial to the evolution of cooperation in ancient hunter-gatherer populations.
Studying how the Tanzania's Hadza people - who are one of the last surviving hunter-gatherer populations - Coren Apicella from Harvard Medical School found that ties between individuals were based on the tendency to cooperate and formed between both kin and un-related members of the group, leading to the altruism and cooperation also needed in society today.
Coren - Well a lot of the properties you see in our networks also hold true in the Hadza. Popular people tend to be friends with other popular people. You see a person's friends tend to be friends with one another. The further away you go geographically, the less likely you are to be friends with a person and cooperative individuals preferentially form ties with other cooperative individuals. So these findings provide crucial insight into the evolution of cooperation and altruism in humans and suggest that social networks have been a fundamental part of human life since ancient times.
The work was published this week, in the journal