This week, The Naked Scientists explore the origin of the HIV virus, laser beams and crushing chemicals.
Plus on 'Stuff and Non-Science', why we think all radio active things glow in the dark.
Chris Smith: Hello, welcome to the Naked Scientists: Up All Night, with me Chris Smith. Coming up, the AIDS virus, scientists have narrowed down the date when it first appeared in Africa, and that’s helped them to solve another mystery in the process.
Kat Arney: There has been the suggestion that in the 1950s researchers were working in the Democratic Republic of Congo to try and develop polio vaccine using a virus, and maybe that caused the creation of HIV. But actually because this research now puts the date of HIV’s ancestors way back to the beginning of that century, it’s very, very unlikely that that’s the source of HIV.
Chris Smith: So the virus emerged much earlier than we first thought. Also this week why people missing a piece of DNA are protected from developing some forms of mental illness.
Ben Pickard: In the Scottish population, which is the one we studied, people who have bipolar disorder have this deletion in around 20 to 30% of individuals; whereas if you look at people who are healthy, don’t have psychiatric disorders, it’s 40%. So you can see here that the protective factor is present is greater numbers in people who are normal, not diagnosed with a psychiatric disorder.
Chris Smith: That’s the genetic basis of bipolar disorder coming up in just a moment. When we’ll also be finding out whether radioactive materials really do glow in the dark. That’s all coming up on this week’s Naked Scientists: Up All Night.
First, let’s take a look at some of the other top science news stories that have come out around the world this with our sage of science, Kat Arney. Kat, welcome, first up, scientists have found a more precise date for when HIV first appeared.
Kat Arney: Yes, it’s fascinating. Well HIV, and that’s the virus responsible for AIDS, has been thought for some time to have evolved in Africa, perhaps as far back as the 1930s, and the oldest known case of infection dates from 1959. And so now research by Michael Worobey and his colleagues have discovered that HIV may have been much more widespread and diverse even back then, which puts its roots back a lot further.
Chris Smith: And what have they done to work this out, Kat?
Kat Arney: Well what they did was analyse genetic material extracted from a lymph node sample collected in 1960 from a woman living in Kinshasa in the Democratic Republic of the Congo, and they looked at the genetic material of the HIV virus in the sample. And then what they did was compare this genetic material with the material from the 1959 sample, as well as the only other pre-1970s HIV sample that we have. So what you can do is construct a molecular clock by looking at how different these samples are from a similar time, to work out how far back in history the original virus must have come.
Chris Smith: Oh right, so in other words it’s exploiting the fact that as HIV passes through people it evolves and changes, and so we know at roughly what rate that occurs, and so by comparing these two samples and showing what the differences are between them, you can pinpoint more accurately when HIV must have first appeared in humans?
Kat Arney: Exactly, it’s really sort of counting the rate of change and working backwards. And, intriguingly, they found that these samples from a very similar time, in a very similar place, were actually very, very different, and using their molecular clock technique they worked out that probably the ancestor to HIV was around way back at the turn of the 20th Century, which puts it back much further than they’d originally thought.
Chris Smith: And what’s the significance of the date when it did appear, was there anything going on in the world at the time that may have triggered it, the question being of course people have been in Africa for millions of years, why have they only now had HIV appear?
Kat Arney: There has been a suggestion that in the 1950s researchers were working in the Democratic Republic of Congo to try and develop polio vaccine using a virus, and maybe that caused the creation of HIV. But actually because this research now puts the date of HIV’s ancestors way back to the beginning of that century, it’s very, very unlikely that that’s the source of HIV. Hopefully it will help researchers to understand where HIV came from and help us to understand the pandemic that we now have in the world.
Chris Smith: And you can read Michael Worobey’s paper on that in this week’s Nature. Also this week, Kat, there’s interesting work being done on how the brain might be really thrown into disarray by eating too much.
Kat Arney: Well yes, if you’re feeling a bit wonky by teatime, it could actually be your mid afternoon chocolate fix that’s been to blame. And writing in the latest issue of the journal Cell, researchers at the University of Wisconsin Madison have discovered that calorie overload can throw critical parts of your brain out of whack.
Chris Smith: Do we know why?
Kat Arney: Well the main player here is the hypothalamus, and that’s the brain main centre for maintaining energy balance. And they’re also really interested in a molecule called IKK beta, which is normally involved in inflammation elsewhere in your body, and it’s normally inactive in the brain. Now scientists have previously found that over nutrition, which is kind of eating all the pies basically, could lead to IKK beta being activated in tissues such as the muscle and liver, and this leads to health problems. And now the researchers have found that a high fat diet can double the activity of IKK beta in the brains of mice, and it’s also high in mice that were genetically predisposed to obesity.
Chris Smith: So when you produce this material, this IKK beta, what does it actually do to the brain tissue, because if it doesn’t affect brain tissue it doesn’t matter, but if it does then that’s bad news?
Kat Arney: Well that’s the key thing. Now they did a bit more research and they found out that this IKK beta activity in the brain leads to resistance to two crucial hormones for regulating body weight, that’s insulin and leptin. And the scientists also showed that blocking the IKK beta in these animals’ brains could protect them from becoming obese. So this discovery is quite interesting, because it suggests that treatments that block this pathway in the brain might be useful weapons in the fight against obesity, and the results also strengthen the idea that over eating promotes inflammation and obesity, that feeds back into your brain, it promotes yet more inflammation and you sort of have this vicious cycle, it’s not just as simple as eating all the pies.
Chris Smith: And so does this suggest then that if you were to put someone on some kind of anti inflammatory drug, like say an Aspirin, they would lose weight?
Kat Arney: Well that’s an interesting idea, but most of the blockers at the moment I think don’t really act in the brain, so you need to get something right into the brain for it to work. So that’s probably an area to explore in the future.
Chris Smith: What about if you get your food from the vending machine?
Kat Arney: Yes, this is an interesting story. Linked to this is a quick report from our file labelled Well Derr. Researchers in the US carrying out a national study aimed at reducing obesity in Type II diabetes in school pupils have discovered that school vending machines sell high sugar and high fat drinks and snacks. According to the researchers changes made to the vending machines in schools will help reduce excess calories taken in by school kids, so no surprises there. And they recommend that vending machines should only sell snacks that have a maximum of 200 calories in them and that might help to reduce childhood obesity.
Chris Smith: I know that some schools in East Anglia in the UK have done trials where they have stopped stocking the kind of high calorie foods you’re talking about and they noticed a significant improvement in the behaviour of their children. But turning now to another problem of mankind, and that’s something that one in three of us will get, cancer. Insomnia’s a major problem with people who get cancer and what are people doing about this?
Kat Arney: Well it certainly is a major problem, and around a third of cancer patients will suffer from insomnia, and it can of course be extremely debilitating for them. The insomnia is often caused by maybe the side effects of their treatment and also the very understandable psychological worry and anxiety that they have about their disease. And the resulting exhaustion and depression and fatigue can really seriously hinder their recovery and also their quality of life. And many of them are really reluctant to start popping sleeping pills, and in some cases it doesn’t really address their main worries.
Chris Smith: Is it just having the worries that makes people not sleep or is there something biochemical going on too?
Kat Arney: Well in some cases it is just the worry, but in some cases it is actually the side effects of treatments they may be on. But now a major study funded by Cancer Research UK and published in the journal Clinical Oncology has shown that a treatment called Cognitive Behavioural Therapy, or CBT, can significantly reduce insomnia in people with cancer, without the need for sleeping pills, so this is great. Now CBT is sometimes known as the talking cure, and it encourages people to explore the reasons why they can’t sleep. And Professor Colin Espie and his team at the University of Glasgow Sleep Centre analysed the effect of CBT in 150 volunteers who’d already been treated for a range of different cancers.
Now all of them had had chronic insomnia for an average of about two years, and they divided the patients into two groups, and one just got normal clinical treatment, whereas the other got small group sessions of CBT given by a cancer nurse. And fantastically they found that the group that got CBT had nearly an hour less of wakefulness, so that’s kind of lying awake and fretting during the night, they were less tired during the day, and they had lower levels of anxiety and depression.
Chris Smith: Do you think that it could also have an impact on survival, because we know that people’s quality of life and how stressed they are definitely impacts on the progression of some of these diseases?
Kat Arney: Well at the moment this study hasn’t looked at survival, but it’s certainly likely because if you can reduce anxiety and depression, if you can improve quality of sleep, you may help to improve recovery and survival, so that’s certainly very interesting. And what’s more interesting about this is that the CBT sessions were given by just a normal cancer nurse who’d had a short session of training. So it should be relatively easy to roll out this kind of treatment. So for something that’s pretty cheap really in these kind of terms, it could have very big benefits for many, many people with cancer.
Chris Smith: And of course these days keeping the cost down is very important. Kat, do you walk under ladders?
Kat Arney: I try not to, and I do have some lucky pants as well because I’m a little bit superstitious. And now some new research from the States published in the journal Science has actually explained why we have a tendency towards superstitions, rituals and believing in conspiracies. And basically it all boils down to a lack of control. Now Adam Galinsky and Jennifer Whitson carried out a series of experiments that showed that people who lacked control over the situation were more likely to develop superstitions.
Chris Smith: So what do you mean by lacked control, is that they just don’t think that if they want to change something they can?
Kat Arney: Well it’s if you’re feeling not in charge of your situation, and to test this they actually set up some situations that featured a lack of control and tested whether volunteers were imagining things or not.
Chris Smith: And what did they ask them to do?
Kat Arney: Well in one experiment people were asked to look at so called snowy pictures, and half of them were pictures of just grainy patterns of random dots, while the other half also contained hidden images that you could just about see. The group of people who felt that they’d lost their control in a previous part of the experiment also saw images in the pictures that were just random dots, so they were basically seeing more things when they felt they were out of control.
Chris Smith: And do we think that this applies to the real world?
Kat Arney: It’s interesting, because they’ve done a few more experiments to try and explore this a bit more, because for the next part of their experiment the researchers asked people to write about situations in the real world where they had either lost control or had control over something. Then they were asked to read out stories in which significant outcomes, for example having a success in a business meeting, was preceded by an unrelated behaviour, for example like stamping your foot three times before you go into the meeting. And the researchers intriguingly found that people who’d originally written about a situation in which they’d lost control were more likely to read superstitious behaviour into the stories that they read out.
Chris Smith: Do we know why people have this sort of thing written into their psyche, why do we behave like that?
Kat Arney: Well the researchers think that probably the less control that people have over their lives, the more likely they are to try and regain control through all these kind of mental gymnastics. In fact it’s not all bad, because the team also found that helping people to focus on their personal values and regain their self control actually meant they were less likely to see imagined pictures or perceived conspiracies, so maybe no more need for the lucky pants.
Chris Smith: Thanks Kat. That was Kat Arney taking a look at some of this week’s other science news stories. And if you’d like to follow up on any of those items, they’re all on the Open University’s website, that’s at open2.net/nakedscientists. This is the Naked Scientists: Up All Night, with me Chris Smith, and coming up how scientists are using laser beams to crush chemicals, with quite surprising results, and we’ll also be finding out whether things that are radioactive really do glow in the dark.
But first to a new study that’s exploring how genes can cause mental illnesses, including bipolar disorder, which is also known as manic depression. This affects between 1% and 2% of the world’s population, and it tends to run in families, and now Ben Pickard and his team at the University of Edinburgh have uncovered part of the reason why.
Ben Pickard: What we try and do in our lab is look for the genes which are responsible for schizophrenia, bipolar disorder and depression, so basically the major psychiatric disorders. And we’ve identified a number of genes, but the one that is in this particular paper is called GRIK4. We identified that a few years ago in an individual who had a chromosome abnormality and was also diagnosed with learning disability and schizophrenia.
Chris Smith: So it was fortuitous that that person happened to have that chromosomal abnormality and those conditions, because it gave you an insight into where on the chromosome to go hunting.
Ben Pickard: Exactly, and that’s exactly how it happened.
Chris Smith: And what was it that you found on the chromosome when you looked there which gave you a clue as to what was causing this person’s symptoms?
Ben Pickard: Okay, so if you imagine how a gene sits on a chromosome, it’s a long string of beads on a string kind of thing, and these beads are the actual axons which make the protein for which this gene encodes. In this individual it was actually chopped, and so we know that that particular gene is sort of inoperative, and because it’s inoperative we think that is the cause of illness in that particular individual. The next step was to try and ask does GRIK4 contribute to psychiatric illness in people who have normal chromosomes. And so what we did was something called a case control association study, where we looked at genetic variation in people who have been diagnosed with psychiatric illness, and compare their genetic variation with people who are healthy, normal. And what we found was two regions of the gene that appear particularly interesting in relation to psychiatric illness.
Chris Smith: And what does this gene do in most people? So in the average healthy person what is their gene that you’ve identified as associated with these two conditions actually doing?
Ben Pickard: Okay, so GRIK4 encodes a protein which makes something called a neurotransmitter receptor. In this particular case it’s a glutamate neurotransmitter. And glutamate is one of these many chemicals which is involved in communication between cells, so it’s kind of fundamental to the way that the brain works.
Chris Smith: And why do you think that this in some way can lead to these two conditions which you’ve identified: bipolar disorder and schizophrenia?
Ben Pickard: So there’s a theory of schizophrenia and bipolar disorder, and what that states, and this is really from studies of particular drug actions, so that’s a drug which has become more notorious as a drug of abuse, so it’s called PCP or Angel Dust. And what that actually does is stop glutamate from binding to the receptors on brain cells, and so inhibits that whole glutamate neurotransmission process. The symptoms are very similar to those with people with schizophrenia. So they have hallucinations, they have delusions, that has kind of led this hypothesis that the glutamate system is very important for schizophrenia and bipolar disorder.
Chris Smith: And why does the change in the gene you’ve spotted do you think cause the condition, what do you think is going on?
Ben Pickard: We found a deletion in part of the message journey, so this is the message that’s produced by the gene which goes on to make the protein. And this deletion doesn’t actually affect the amino acids which make up the receptor, but what it does do is seem to affect the stability of this message in a cell. We actually have more glutamate activity, more glutamate neurotransmission, and so this deletion that we’ve identified seems to have this protective effect by just increasing, sort of modulating the amount of glutamate neurotransmissions that goes on in the brain.
Chris Smith: And in the group of individuals that you studied, what proportion of them carried this protected versus the risk factor versions of the gene?
Ben Pickard: So what we see is that in the Scottish population, which is the one we studied, people who have bipolar disorder have this deletion in around 20 to 30% of individuals; whereas if you look at people who are healthy, don’t have psychiatric disorders, it’s 40%. So you can see here the protective factor is present in greater numbers in people who are normal, not diagnosed with a psychiatric disorder.
Chris Smith: But at the same time there’s still a very large number of people who have got the condition and don’t have that deletion, suggesting that there’s quite a lot else still to find for this condition isn’t there?
Ben Pickard: Exactly, this isn’t the only answer, it’s just a piece in the jigsaw, and so what we’ll be looking for, and I guess over the next few years, is genes like this which as a collection which allow us to perhaps begin to sort of get some sort of diagnostic possibilities. Either diagnostic so that we can sort of work out people may go on to develop disease at a later time in their life, or perhaps diagnostics which will allow us to tailor drug treatments to them so that they will get the best drug for their particular type of schizophrenia or bipolar disorder.
Chris Smith: Edinburgh University’s Ben Pickard explaining how a broken chromosome has led him to uncover a gene that’s linked to bipolar disorder and schizophrenia. They’ve published that work in this week’s edition of the journal PNAS. And now to another pressing problem in science, or perhaps that should be compressing problem, which is to understand how chemicals alter their behaviour when they’re placed under intense pressure. Strange things can happen when you do this. For instance insulators can begin to conduct electricity, and hydrogen behaves a bit like a metal. But finding a way to squash things sufficiently hard, whilst you’re simultaneously trying to study them has proved almost impossible until now. Because Andrea Cricher and Siegfried Glenzer have solved the problem with a very powerful laser, which is helping them to shed some light on some of these unanswered questions.
Andrea Kritcher: We want to learn more about compressed states of matter that basically compress more than a million times greater than atmospheric pressure. These types of matter occur in the way that planets were formed. We want to understand the material properties that are not currently known under these conditions.
Chris Smith: So what sorts of things do you suspect are going on when you put a big squeeze on a substance, why would it change?
Andrea Kritcher: So it changes in structure, the way that the atoms are arranged and molecules can change. And only now have we been able to access these states of matter with this technique, and also by creating the states of matter with high powered lasers in the lab.
Chris Smith: So if I could come to you, Siegfried Glenzer who’s also involved in this project, how are you creating the intense compression of the materials in your laboratory that Andrea’s just been talking about?
Siegfried Glenzer: So we have built a series of laser facilities in Livermore that produce very energetic laser beams, and focus that laser light on a solid. The laser light first of all heats the surface, then the surface material is released and launches a shockwave, and the shock is squeezing the material.
Chris Smith: And then how do you measure what the effect of that is, because that’s a key thing, because like Andrea was saying it’s very difficult to make these measurements and see what’s going on inside the material, to probe this effect. So how are you able to unlock that secret, and find out how the material changes when you squeeze it like this?
Siegfried Glenzer: Yes, so we use penetrating X-rays. The extremely short laser process that we fire onto a separate foil, and they emit for 10 picoseconds, which is a very short amount of time, and that allows us to probe the changes in material composition and the change of the density. So you have one beam that compresses the material and another beam producing X-rays, and then you use the X-rays to scatter all the compressed metal.
Chris Smith: Oh I see, so the X-ray beam that flashes out from the squashed material tells you something about the structure of the material and what’s going on inside the material. So, Andrea, when you did the experiments what did you see, and what did you squeeze?
Andrea Kritcher: We squeezed lithium hydride targets, that’s solid density which is .78 grams per centimetre cubed. And after we compressed it we measured that the density had changed from solid density to three times solid density, which is 2.2 grams per centimetre cubed. And from the scattered X-rays we also measured that the temperature reached temperatures of 25,000 Calvin, which is extremely hot.
Chris Smith: Well it’s certainly hotter than the surface of the sun by quite a considerable number of degrees, so why did you look at lithium hydrides specifically?
Andrea Kritcher: Lithium hydride is a really light element, and it’s relevant because most of the elements in the atmosphere are very light as well. So this helps us determine whether or not we can test other light elements in the atmosphere for planetary formation studies.
Chris Smith: And Siegfried, how does this inform what we think was going on in the early solar system when planets like the Earth and maybe the bigger gas giants actually got put together?
Siegfried Glenzer: The big question that people are looking at is whether or not the gas giants have a solid core, and scientists presently using models to predict whether solid core is indeed present in Jupiter and Saturn. And so we need good quality experiments to test our modelling and first principle simulation, and that’s what this new technique is going to provide.
Chris Smith: So do you think then that the pressures that you’ve got on Jupiter are sufficient to make the same changes that you saw here with the laser beam?
Siegfried Glenzer: Yes.
Chris Smith: Actually apply it on Jupiter.
Siegfried Glenzer: Yes definitely, I mean we have exactly produced the pressure conditions in Jupiter yes.
Chris Smith: And with our feet back firmly on planet Earth, are there any applications that will inform science in other ways here and now?
Siegfried Glenzer: Yes, right now we are building the National Ignition Facility here in Livermore, which is a 192 laser beam facility. It’s a goal to compress metal to the state of one thousand times solid density. And in that case we want to create a microscopic standard laboratory for nuclear fusion.
Chris Smith: So you think that it would be possible to use the same techniques to confine and constrain and compress matter in order to initiate fusion reactions so that we can basically reproduce the Sun on Earth and produce lots of electricity?
Siegfried Glenzer: Yes, so this experiment is like a precursor experiment. So Andrea has used two shockwaves in her experiment. So she used a very precise laser pulse to launch one shockwave and shortly afterwards a second shockwave, and then we do our experiments, the National Ignition Facility, the goal is to launch four shockwaves. The series of four shocks on this will produce the conditions that are needed for heating and compression to create a microscopic standard laboratory.
Chris Smith: Siegfried Glenzer and Andrea Cricher, they were talking to me about the work they’ve published in this week’s edition of the journal Science. They’re based at the Lawrence Livermore Laboratory in California.
This is the Naked Scientists: Up All Night, with me Chris Smith, and it’s time now for this week’s Stuff and Non Science, where we blitz myths and bash bad science. And with a radioactive issue on her hands, here’s Diana O’Carroll.
Diana O’Carroll: Hello and welcome to 'Stuff and Non Science', with an altogether more luminous myth. The TV would have you believe that radioactive things, and even people who have been exposed to radiation, will glow in the dark. Mark Peplow with the truth.
Mark Peplow: The truth is that radioactive things don’t glow in the dark, at least not on their own, but their radioactivity can sometimes trigger other materials to emit light. The energy in the radiation excites electrons in these phosphorescent materials, and when the electrons relax again they let out a burst of light. In the first half of the 20th century, the radioactive metal radium was widely used to make self luminous paints, cropping up in anything from watches to instrument panels - mixing the radium with the phosphorescent zinc sulphide, with just a dash of copper added, created the familiar greenish glow that we tend to associate with radioactivity.
There is another way that radioactive stuff can appear to glow, by a process called Cherenkov radiation. I used to work in a lab next to a small nuclear reactor which made isotopes for medical research. The core of the reactor sat at the bottom of what essentially looks like a big swimming pool, and the core was surrounded by a ghostly blue aura. That’s because the radiation coming from the core suddenly has to slow down when it hits the water, and to slow down it needs to eject some energy, which it does in the form of blue light. It’s an absolutely beautiful effect, but you certainly wouldn’t want to go swimming in it.
Diana O’Carroll: Not all that glows in the dark is radioactive. If you have a science myth that’s fit to be flattened, then send it to me at Diana@thenakedscientist.com.
Chris Smith: Thanks Diana. That’s Diana O’Carroll with this week’s Stuff and Non Science. She was talking to Dr Mark Peplow, the man with three arms and five legs, thanks Mark.
Well that’s it for this time. We’re back next week with another round up of the world’s hottest science. The Naked Scientists: Up All Night is produced in association with the Open University, and you can follow up on any of the things that have been included in the programme this week via the OU website, that’s at open2.net/nakedscientists. The other way to get there is to follow the links from the Five Live Up All Night web pages, which also point to the Open University. Production this week was by Diana O’Carroll and Ben Vasler, they’re at the nakedscientists.com, and I’m Chris Smith. Until next time, thank you for listening, and goodbye.
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In the news
'Direct evidence of extensive diversity of HIV-1 in Kinshasa,'
by M Worobey, M Gemmel, D Teuwen, et al
in Nature Vol 455, p661
'Hypothalamic IKKß/NF-©§B and ER Stress Link Overnutrition to Energy Imbalance and Obesity'
by X Zhang, G Zhang, H Zhang, et al
in Cell 135, 61–73, October 3
'Randomized Controlled Clinical Effectiveness Trial of Cognitive Behavior Therapy Compared With Treatment As Usual for Persistent Insomnia in Patients With Cancer'
by C A Espie, L Fleming, J Cassidy, L Samuel, L M Taylor, C A White, N J Douglas, H M Engleman, H-L Kelly, and J Paul
in JCO (Journal of Clinical Oncology) Oct 1 2008: 4651–4658
'Lacking Control Increases Illusory Pattern Perception'
by J A Whitson and A D Galinsky
in Science 322, p115
'A common variant in the 3'UTR of the GRIK4 glutamate receptor gene affects transcript abundance and protects against bipolar disorder', by B S Pickard, H M Knight, R S Hamilton, et al in PNAS 105:39
'Ultrafast X-ray Thomson Scattering of Shock-Compressed Matter', by Andrea L Kritcher, Paul Neumayer, John Castor, et al in Science 322 pp69