Chimaeric human / animal hybrid embryos – what’s going on?

On Wednesday 5th September, the UK’s Human Fertilisation and Embryology Authority (HFEA) announced their decision that British scientists can press ahead with research to generate animal / human hybrid embryos, also known as embryo chimaeras. Certain sections of the media have got very overexcited about this type of research, drawing unhelpful cartoons of humans with rabbit heads and the like – but what exactly is this technology all about?

Put simply, creating chimaeric animal / human embryos means taking an unfertilised animal egg – such as from a cow or rabbit – and removing the DNA from it. Then the empty egg is fused with a human cell, and the process of development re-activated.  The embryo is then allowed to grow for just a couple of days, until it is a tiny ball of cells. 

At this stage, the scientists can extract embryonic stem cells from the developing embryo, which can be used to generate all the different tissues of the body.  Many scientists believe that such embryonic stem cells could be the key to treating many human diseases – for example, using them to replace the brain cells lost or damaged in conditions such as Parkinson’s or Alzheimer’s.

Because the animal egg’s DNA would be removed before the human cell is added, the resulting stem cells will be essentially human.  However, there will be a small amount of animal DNA present. This is because egg cells have structures called mitochondria, which provide energy.  These contain their own miniature chromosome in the form of a small circle of DNA, which controls how they behave. It too would be passed on in the stem cells. But any fears that rabbits with human heads will be hopping around the place are unfounded, because in any case the embryos would be destroyed at the stage when the stem cells are harvested, and not be implanted into the womb to develop further.

At the moment, human embryonic stem cells can only be created from human embryos, which are understandably in short supply.  Many people also raise significant ethical objections to the use of human embryos in research.  By using these hybrid embryos, scientists would totally avoid the need to use human eggs or embryos to generate stem cells.   Although there are still people who have ethical objections to this technique, it is important to point out that such technology would effectively reduce the need for experiments on human embryos. 

Many scientists and research organisations around the world believe that research using animal/human hybrid embryos is important – especially given the practical and ethical limitations of working with human embryos.  If we truly believe that stem cells are a viable technology for treating serious human diseases in the future, then embracing hybrids may have to be a necessary step along the road of scientific progress.

More info here: news.bbc.co.uk/1/hi/health/6978384.stm

2nd Sep 2007

Plants can hear - so it might make sense to talk to them after all

Korean researchers claim to have discovered two sound-sensitive genes in rice plants.

Mi-Jeong Jeong and colleagues from the National Institute of Agricultural Biotechnology in Suwon, South Korea, made the discovery by exposing plants to noise and studying how this affected gene activity.  Initially they tried playing 14 samples of classical music to their rice, including Beethoven's Moonlight Sonata, but saw no response.  Then they tried playing sounds of specific frequencies and began to see a change.  At 125 Hz and 250 Hz the activity of two genes, rbcS and Ald, went up.  When sounds at at 50 Hz were played the gene activity went down.  Then, to find out whether other genes could be rendered sound-sensitive, the team linked the genetic elements that control the Ald gene to a "reporter" gene inserted into the rice called GUS (beta-glucuronidase).  They found that sounds could then also manipulate the levels of GUS.

This suggests that it might be possible to use sound instead of chemicals to control different genetic processes in plants, such as switching on resistance genes to help them fight off pests or ripen more rapidly. 

Not all scientists are convinced though; some say that the new research, which is published in the journal Molecular Breeding, makes use of old techniques and lacks sufficient numbers to make the data credible.  Sounds like sour grapes, although it does suggest that it's not just cereals like wheat and barley that have "ears"...

2nd Sep 2007

Spiderman Suit Inches Closer

The dream of being Spiderman- or Spiderpig if you're a fan of the Simpsons - could be a step closer after the latest research by a group of Italian physicists.

Over the past couple of years scientists have started to understand how creatures like geckos and spiders can run effortlessly up walls. Their feet are covered with tiny hairs, and they stick to surfaces using the combined power of the weak atomic attraction between the atoms in their feet, and the atoms in the surface they're on, known as van der Waals forces.

Some researchers have tried to make adhesives based on this technology, such as Geckel - which was in the news recently. But researchers have been sceptical that these could ever support the weight of a human.

Professor Nicola Pugno, engineer and physicist at Polytechnic of Turin, Italy, has done some sums to show that a combination of carbon nanotube-based "Velcro", along with the van der Waals forces might be enough to support human, and make our Spiderman dreams come true.

This could potentially be used in many ways, from space exploration to sticky boots and gloves for window cleaners on skyscrapers. The technology could even be used underwater.

But before you get carried away with your Spidey-dreams, I have to tell you that the work isn't even at the prototype stage yet. And it may be that our human muscles simply aren't up to the task - unlike a gecko, we would suffer from terrible muscle fatigue if we tried to cling to a wall for hours.

2nd Sep 2007

World's smallest thermometer - a single molecule

Researchers have found that a green-glowing chemical from a jellyfish can be used as a molecular thermometer.

Known as GFP - green fluorescent protein - the substance is used by biologists to harmlessly label cells. Shining light of a certain wavelength at a cell containing GFP causes the molecule to flash up green. But a closer look at the green light given out reveals that it is not continuous and instead rapidly blinks on and off as the molecule subtley alters its structure.  Now Cecile Fradin and her colleagues from McMaster University in Hamilton, Ontario Canada, have found that the rate of blinking corresponds to the temperature - when things get hotter the blinking slows down, whilst at cooler temperatures the blinking speeds up.

To find out whether this could be used as a miniature optical thermometer the team measured the blink rate at different temperatures between 10 and 50 degrees C.

Writing in the Journal of the American Chemical Society, they found that with this technique they could make measurements to within an accuracy of 1 degree. Previously researchers had tried to use dyes which glow more brightly at different temperatures, but these can be misleading if several molecules congregate together producing a brighter light. The new discovery is likely to prove useful for temperature monitoring applications on miniature lab-on-a-chip diagnostic devices, and even for measuring the temperature of different structures inside living cells.

2nd Sep 2007

Pygmy FM

Big businesses are notorious for being difficult to get through to, especially if you cannot read and write and the company happens to be cutting down the forest in which you live. Well, now technology has come to the rescue with what has been nicknamed Pygmy FM. Here is Mike Hopkin.

Michael Hopkin: For thousands of years, there have been Benjelle Pygmies who have lived a hunter gatherer lifestyle in heart of the northern Congo. Unfortunately for them, their home is slapped bang in the middle of one of the world's richest sources of prime hardwood and these semi-nomadic people are forced to share the forest with international logging companies. For years, the Benjelle have accepted logging as a fact of life without much means to air their grievances with CIB, the company that holds extensive logging rights in the Republic of Congo, the pygmies have been unable to tell the loggers which trees they would like to see left alone, but now with consumers demanding more sustainably harvested timber, CIB has realized that its profits are at stake. So, it has enlisted the help of development groups to set up a community radio station that aims to allow the Benjelle to speak up. I asked Scott Poynton of the Tropical Forest Trust, charity that promotes responsible forest management about the need to put the Benjelle on the air waves.

Scott Poynton: Part of the problem was the pygmy communities living in that area, well throughout central Africa really is that they are semi-nomadic. Today, they can be in one place and tomorrow they will be somewhere else. They are also non literate. You know, you cannot send them a letter. They do not have a letterbox that you can contact them through and also they are an egalitarian society so they do not have a village head. So, you cannot just go and talk to one person. So, it was actually Jerome Lewis's idea and Jerome and I been working with these pygmy communities for many years. Jerome had the idea of establishing a radio station, by which using, you know, robust wind up radio technology that we could have some broadcasts made by the communities themselves whereby they can communicate with the company and the company can create its own broadcast and thereby establishing a dialogue, not a direct dialogue, anyhow sort of two-way dialogue, but a dialogue nonetheless where ideas can be exchanged and the thoughts of the communities can be put on air and that can reach the company.

Michael Hopkin: The radio station at first perhaps inevitably nicknamed Pigmy FM has now been formally named "Bisso na Bisso," which means "between us" in the local Lingala language. A few pilot shows have already been made and in the traditional community radio style, feature mix of debate and music, but the pygmies still need a way to tell CIB exactly which trees they particularly value and this is where the project gets really clever. With the help of anthropologist Jerome Lewis of the London School of Economics, who has lived on and off with Benjelle for years, the project's organizers have created special handheld computer consoles for the pygmies to carry while roaming through the forest. The devices use GPS to log automatically the locations of important trees and sites. That way CIB, which has always practiced selective logging can avoid these precious specific resources.

Jerome Lewis: They put together a series of icons and have a decision tree whereby the pygmy communities can go into the forest and that is a very easy technology. It takes about five minutes to explain what it is all about and the pygmies are pretty smart people. They know what is going on. They have never seen a computer before, but they can work out what this technology is aiming to do and I have advised it because they can guide into the forest and say, 'look here is a sacred area so they can click on the icon that shows the sacred area and then they can click on the reason why it needs to be protected. It is a sacred area for the women or is it sacred area for traditional festivals, and in some cases they do not actually go down to that far because some of that knowledge is in fact confidential and sacred and they do not share, but in other cases they say 'look, here is an area we just need to protect it because we need to protect it' or 'here is an area where we gather food' or 'here is our watering hole' and so through that process they have been able to map large areas of forest that they use. These maps are then produced. They go to the company. They say, 'hey, look these are the areas we would really appreciate you to keep your bulldozers out of them, please do not fell these trees for example because in the dry season we harvest the caterpillars from those trees'. It is an important food product. And so what has happened is there is a dialogue being started through this handheld.

Michael Hopkin: The radio station will also benefit the pygmies in other ways. It will give them better access to information about doctor visits, vaccinations, and AIDS awareness.

Jerome Lewis: Everyone can make their own programs and put out their stories, their concerns and their music. We can make sure that information about the visits of the doctor are kind of getting out, because in the past for example the doctor would go out to make a vaccination program for the children, but half the children would be in the forest, you know, for one reason or another and so, there are issues like that but if we can sound radio, hey look, you know, at the second moon or whatever the doctor will be at this place, then the chances of helping these communities and the kids out there to get their vaccinations is going to be much stronger.

Michael Hopkin: The project's organizers have already started using the mapping technology in other neighbouring countries in the Congo basin, particularly the vast Democratic Republic of Congo to the East. It looks like the pygmies of the Congo are finally finding their voice. (Voice in Lingala language)

Chris Smith: It sounds like they are certainly on the right wavelength with that particular approach.

September 2007

Science Update - Bad Diet Food and the Placebo effect

Bob -   This week for The Naked Scientists I’m going to talk about why diet foods might actually make kids fat. But first, Susanne’s going to tell us why the placebo effect works on some people and not others.  

Susanne -   Some patients get powerful pain relief from a sugar pill if they're told it's real medicine. It’s called the placebo effect, and scientists have long puzzled over what causes it, and why it helps some people more than others. Now University of Michigan neuroscientist Jon-Kar Zubieta and his colleagues have found that people who get the most pain relief from placebos also show increased activity in a tiny region of the brain called the nucleus accumbens.

Jon-Kar Zubieta (University of Michigan):  So, basically, what this was telling us is that placebo activates dopamine and the magnitude of activation in this particular brain region predicted how well the placebo was going to work in these individuals.

Susanne -   Zubieta doesn’t know why some people have more dopamine activity in the nucleus accumbens, and therefore respond better to placebos, but he thinks genetics may play a role.

Bob -   Thanks, Susanne. A new study suggests that popular diet foods could actually cause children to overeat and gain weight.  A team of researchers at the University of Alberta found that when they fed juvenile rats low calorie foods that taste just like higher calorie versions, the rats began to overeat their normal diet.  Sociologist David Pierce explains.

David Pierce (University of Alberta):  In the young juvenile rat, their bodily system is in some sense fooled by the taste cue, such that the body thinks that it hasn’t had any calories, so they ate more at their regular meal.  

Bob -   Pierce says that rats and humans have a similar response to taste conditioning, so children might be prone to overeat if exposed to diet foods when they’re young.  Instead, he suggests offering kids healthful, nutritious meals and leaving the low-calorie options on supermarket shelves.  

Susanne -   Thanks, Bob. Next time, we’ll tell you about a computer with a sense of humour. Until then, I’m Susanne Bard…

Bob -   …and I’m Bob Hirshon, for AAAS, The Science Society. Back to you, Naked Scientists…

September 2007

Out of Body Experiences - On Demand!

Meera -   An Out of Body experience…An experience that typically involves a sensation of floating outside ones own body and, in some cases, seeing ones physical body from a place outside ones body.

This is probably something you would normally only associate with stories from people who have just come off the operating table or enjoy their share of psychedelic drugs but now, for the first time, two scientific teams have been able to induce Out of Body Experiences, or OBE’s as they are known, in healthy volunteers.

But now, two teams led by Professor Olaf Blanke from Ecole Polytechnique in Switzerland, and Dr Henrik Ehrsson from UCL, have managed to create the eerie effect of an out of body experience in normal awake people - just with the aid of a virtual reality headset and a back rub! And they think the discovery might help, amongst other things, to train better surgeons.

But how did they do it? Well, volunteers were rigged up with goggles containing miniature screens onto which the researchers could project images from a video camera.

The camera was positioned behind the volunteers so that they could see themselves from behind on the screens in their goggles.

The researchers then took a rod and rubbed the subjects on the back, which they could also see on the images from the camera.

This fooled the subjects' brains into thinking that the projected images they were seeing on the screen was them outside of their own body, as Dr Henrik Ehrsson explained, when the discovery was announced recently at a meeting in London...

Henrik Ehrsson:  The idea is to manipulate, to change, the visual input or its relation to the tactile information. If we change it in the right way, we should be able to change the feeling of where yourself is located in space. We should be able to move it to a point outside your physical body. Even induce out of body experiences.

Meera -   Surely nobody would fall for this would they? I managed to speak to Olaf himself to find out what happened.

Olaf Blanke:  We tried to manipulate where you see being touched and where you fell being touched. We were interested in learning whether by doing such a procedure and later asking subjects where they really believed they were, whether we could displace them or make them insecure about where they really are. This is what we have hopefully accomplished, at least the first step, with this.

People were filmed from the back, a camera was standing 2 metres behind them, and their back was stroken with large pen. This was filmed in the realtime and projected to a head-mounted display (goggles). So they would see their own bodies being stroked 2 metres in front of them. What then happens after a while is that you really start localising and feeling the touch, where you actually see it. So what this then suggested to us is that the partial phenomenon of an out-of-body experience can be reproduced in completely healthy subjects.

Meera -   I have to admit I’m quite upset that we didn’t get to have a go on it today. I know you actually had a go yourself so can you explain how you actually felt when you had a go?

Olaf Blanke:  A lot of subjects thought it was kind of strange and weird. What I had was a really strange sensation that you feel the touch where you actually see the touch, although as a subject you know that this is absolutely not the case, you have partial insight into the experiment. Even as the person who set up the experiment I should be even more aware that this shouldn’t work! But actually it does work, so I think it’s a nice finding because it seems to be so automatic, based on brain mechanisms that you cannot control by higher mechanisms; language, memory, thought.

Meera -   I know that some of the application that have been discussed have been gaming which is an obvious one, but also you mentioned surgey? I don’t really understand how that could happen.

Olaf Blanke:  It needs to be tested and I’m sure a lot of surgeons would be immediately hesitant to even try it but a lot of people who don’t operate actually but who want to learn to operate; I think for them it could be interesting that they are somehow linked to the motor inputs and tactile inputs from the real surgeon. That might be much more actively perceived than just watching the operation.

Meera -   So, ambitious medics could soon feel the dexterity of their awesome supervisors…and forget about the new generation of motion sensitive consoles, soon you could fight monsters head on in the world of gaming! All by causing confusion between your senses.

These studies looks like the beginning of a lot more research into this OBE’s, tricking further volunteers into believing they’re somewhere else. But self-consciousness is a principle pondered not only by scientists….but philosophers as well. I’ll leave you with Thomas Metsingers insight…

Thomas Metsinger:  What we have created really is what philosophers call non-conceptual self-consciousness on a bodily level with only two sensory modalities. You just stand or sir there, but still you get this externalised self-location and this seems also to show that it is very old, very low level brain mechanisms that are responsible for our everyday experience of being an embodied self.

September 2007

Warping Wineglasses

Amaze your friends at a party by making some really strange sounds from a wineglass.

What you need

A good quality crystal wineglass that rings for several seconds after you ping it.

A little water

A finger

What to Do

Fill the glass with about 1-2cm of water

Make sure that your finger isn't greasy,

Wet your finger and gently slide it around the glass. It should start to ring nicely.

Get it ringing really well and then stop. The ringing should die away over a few seconds.

Now do the same thing but while the glass is still ringing pour the water out.

What happens?

What may Happen

You should find that the pitch of the ringing drops as you pour the water out, but if you let the water run back the pitch will go back up.

You can try it as many times as you like, try varing the amount of water and the speed at which you pour it out.  You could even try tilting the glass, then getting it ringing and straightening it up - you will find the pitch goes up.

What is going on?

When you move your finger around the glass it tends to stick, then slip then stick again which tries to vibrate the glass. The glass vibrates very well at a few frequencies in a similar way to a swing (if you push the swing at the right rate the swing will build up, at the wrong rate and you generally get hit in the face...). So if your finger is vibrating the glass at the right speed the glass' vibration will build up to the point where it vibrates the air, creating the sound that you can hear. This effect is known as resonance and the frequency it happens at is known as the resonant frequency.

The glass actually vibrates by deforming the rim first into an oval in one direction and then into one in the other.

Different glasses will vibrate well at different frequencies, in much the same way as different guitar strings will produce different notes.  A glass with a large rim will vibrate at a lower frequency and therefore pitch than a smaller glass.

When you start to pour the liquid out of the glass the water moves over the part of the rim that is vibrating the most.  This makes the rim heavier, and the added weight is more difficult to accelerate in and out, this means the vibration happens more slowly and so the pitch goes down.  If you remove the water from the rim, either by pouring it out or straightening up the glass, the pitch will go back up again.

For the same reason strings on a bass guitar are made much heavier than on a normal guitar, as heavier strings vibrate more slowly allowing it to play much lower notes.

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Written by Dave Ansell