Monthly Archives: March 2011

Blood Groups Could Become a Thing of the Past

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Written by Matt Farley

 

New research from McGill University in Canada could do away with the need to classify blood by ‘type’, following a new technique to prevent mismatched blood from being rejected after a transfusion.

Along with the well-known A, B and O blood groups, there are a further 26 different blood types which have to be matched carefully when carrying out a blood transfusion – a mismatch can lead to the donated blood being rejected by the body which can be fatal. The ideal situation is for a ‘universal’ blood type which would be compatible with any recipient blood type.

Rejection occurs when the antigens on the surface of the donor red blood cells are of a different type to those on the recipient’s cells – previous attempts at avoiding this have focused on either removing the surface antigens from the donated blood using enzymes, or producing the blood outside the body from stem cells. These techniques have shown some success, but are hindered by their expense and complexity. The latest method, presented by Dr. Maryam Tabrizian and colleagues, instead aims to cover up the antigens and hide them from the host immune system – known as ‘immunocamouflage’.

Red blood cells from a selection of volunteers were coated in a layer of polyelectrolytes – small repeating units which self-assemble on the cell surface. Previous attempts at coating cells in this way using yeast and E.coli had shown promise, but it remained to be seen whether the delicate red blood cells would be able to withstand the process.

After coating, the cells were exposed to their opposite antibody and observed for any agglutination, or clumping of cells, that occurred. The coated cells were shown to remain free after addition of the antibody, suggesting that the antibodies had failed to recognise and bind the cell surface antigens. This was in contrast to the uncoated cells, which clumped together in the manner normally seen when mismatched blood samples are mixed.

Perhaps most importantly, the red blood cells showed no significant reduction in their ability to take up oxygen, implying that they would still be able to carry out their function within the body. The cells were also seen to produce ATP, an energy carrier – a good sign that metabolism was also functioning as normal.

It remains to be seen whether the technique will be as effective when tested in a living organism, but the results obtained so far appear promising. If effective, future blood transfusions could become a lot easier, and a lot less dangerous.

The paper accompanying this article is available online:

http://pubs.acs.org/stoken/presspac/presspac/full/10.1021/bm101200c

Red blood cells

Life Ascending

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Reviewed: ‘Life Ascending: The Ten Great Inventions of Evolution’ by Nick Lane

In October 2010, the Royal Society Prize for Science Books went to Nick Lane for his book ‘Life Ascending’, so it only seemed appropriate to give it a read and see what all the fuss was about. Thankfully it won’t be the last book prize the Royal Society will award, which looked likely to be the case until recently, since Winton Capital Management have signed a 5 year sponsorship deal giving birth to the mouthfilling Royal Society Winton Prize for Science Books. Excellent.

With such high acclaim I approached Life Ascending with some enthusiasm, which was rapidly deflated when I found out Nick Lane is a biochemist – a field that has never exactly grabbed my imagination. But it is testament to Lane’s skill as a writer that he managed to keep me not just engaged but enthralled while explaining some of the finer points of biomolecular processes. However the book is more than just biochemistry, it is a run-down (or rather run-up) of 10 inventions of evolution that have had the greatest impact on the world, ranging from conditions in which the first proteins and genetic molecules were formed right up to consciousness and, surprisingly, death.

Of course, such a sweeping tour of the history of life on earth covers huge swathes of scientific topics, each with their own history, points of debate and unsolved mysteries, and Lane guides the reader through with what he personally regards as the most plausible theories. In doing so, he fills you in with lots of interesting backstories, eccentric scientists and industry quips (like “the second law of Leslie Orgel: Evolution is cleverer than you are”). For fear of getting lost in the details and asides the reader is often brought back to the big questions, such as why life only arose once from the common ancestor of all living things, or the evolutionary logic behind death. I think this is the greatest strength of the book: the mixture of light asides, big questions and fascinating details all held together in a logical structure that equally entertains and informs.

Lane receives a lot of praise for the elegance of his writing, and it is certainly displayed in passages like the description of the “futuristic cityscape” of the inner workings of a cell from the point of view of a single biomolecule. It is in the more biochemical chapters that you feel Lane is at home and enjoyably in command. While the later chapters are still fascinating (I was blown away by how birds’ lungs work), they don’t quite have the sparkle or the argument of earlier chapters – consciousness in particular was more of a run-through than a narrative. Nonetheless, it is clear why Life Ascending was awarded the Royal Society prize: Nick Lane makes a fantastic tour guide through the wonders of evolution.

Next to be reviewed:

‘Trick or Treatment?’ by Simon Singh and Edzard Ernst – the book that kicked off Simon Singh’s well publicized libel case. I’ll try and keep the defamation to a minimum…

Losing DNA made us human

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Written by Olivia O’Sullivan

 

A study has shown that it may be DNA we have lost which sets humans apart from our nearest primate relatives. 

The majority of mutations in DNA are harmful, and a loss of genetic information might be assumed to be catastrophic. In a paper published last week in Nature, a team of researchers from Stanford University in California have challenged this by identifying the loss of particular regions of non-coding DNA to be a key factor in shaping our unique minds and bodies, thus setting us apart from chimpanzees and the rest of the animal kingdom.

By conducting a genetic comparison of the human genome with that of a chimp and a macaque the team found 510 DNA sequences missing in humans that were present in chimps, almost all of these sequences were from the non-coding region of DNA, i.e. chunks of DNA responsible for turning genes on or off . Two regions of particular interest were the androgen receptor (AR) gene and ‘GADD45G’ – a tumour suppressor gene involved in brain development.

The AR gene is implicated in the production of hard, keratinized penile spines which are found in many mammals and play different roles in different species. It is thought that penile spines may have been used as a way of competing with other males for mating partners by removing the sperm of competitors. It is believed that the molecular changes resulting in a loss of human penile spines has allowed us as a species to form more complex social structures by adopting monogamous reproductive relationships.

Another ‘lost section of DNA’ in humans was found to code for a tumour suppressor gene that normally acts to suppress brain growth, putting an evolutionary brake on the growth of specific brain structures zones in our primate relatives. This ultimately paved the way for the evolution of a larger human brain, giving us an intellectual edge over our fellow animals.

The results of this study certainly underlines the fact that genetic information is both gained and lost during evolution and that despite sharing approximately 96% of our DNA with chimpanzees, it is thought that this genetic divergence may have occurred more than 800,000 years ago when our ancestors split from the Neanderthal lineage. This is an exciting finding, opening up new areas for discovery through the analysis of the remaining 508 DNA sequences which promise to reveal further secrets about the molecular basis of human individuality.

 

References:

McLean, C. Y. et al. Nature 471, 216-219 (2011)

Attention all amateur photographers and skywatchers

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Tomorrow, weather permitting, we should all be in for a treat in the night sky as we see the rise of a ‘Supermoon’. This however is nothing to fear but just two ordinary lunar events coinsiding with each other.

So, a super moon occurs when the moon is closer to the Earth than on average in it’s orbit, this is most noticeable when happening at the same time as a full moon. Tomorrow night this will lead to a very large moon rising in the night sky, which on average should look around 14% bigger and 30% brighter.So how does the moon find itself closer tomorrow night? Much like the orbits of the planets and their satellites the moon’s orbit is slightly elliptical which means that at 2 different points it has a minimum distance from the Earth (the Perigee of the orbit) and at another a maximum distance from the Earth (the Apogee of the orbit). It is the Perigee of the orbit that coincides with the full moon tomorrow night.

 

Knowing the gravitational effect that the moon has on the Earth and the effects of the tides some bloggers and tabloids have suggested that the Supermoon could affect the tides drastically and cause adverse seismic and volcanic activity (obviously using last week’s problems in Japan to strengthen their ‘theories’). The effect of the moon being closer to us at this point however are negligible. In terms of tides a Perigean tide is only 15 cm greater than normal at the very most, and seismologists running many studies over the years have seen no increased seismological effects due to a supermoon.

Without no specific reference points to measure the size of the moon in the sky astronomers suggest observing the moon as it rises over areas that have buildings/trees etc in the foreground to take advantage of a magnifying effect the low atmosphere also has. So if you have the chance get out, have a look at a supermoon and maybe take a picture or two and load them up onto our forums.

 

I feel it may become customary for me to add a song at the end of a blog post as I am leaving another here.

 

 

Enjoy.

(Also apologies for another Astronomy/Space Blog entry, some different physics subjects will come soon! And apologies for attacking tabloids again, it’s a result of anger at poor science articles)

Increased Solar Activity, how will it affect me?

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Over the past month it has been reported that several large solar flares (or coronal mass ejections) have sent a mass of charged particles in the towards us indicating that after an extended period of relatively low activity, the sun is beginning to ‘wake up’. Accompanying these reports in the tabloids have been the generic sensationalist stories saying that the sun is going to let out the ‘big one’ and wipe us all out be it through the amount of charged particles hitting the Earth inflicting a high level of radiation upon us or that these will cut all of our electricity and we will be thown back into a pre 20th century darkness. Not only have the tabloids been jumping on the end-of-the-world-due-to-a-solar-flare scenario, films such as 2012 and ‘the knowing’ have used this as a major storyline. However, how much truth is in these stories and films? What will increased solar activity mean to you and I?

1. Satellites

Solar flares occur from a release of stored magnetic energy from sunspot activity, as a result charged particles are thrown out into space. These charged particles can affect and potentially shut down some of the many satellites orbitting the Earth having a profound affect on the way we go about our general day to day tasks. Understandably the different types of satellite such as, navigation, military, communication will effect different people in different ways. Periods of high solar activity occur on average every 11 years,  the last time there was a peak the world was a very different place and we weren’t so dependent on technology. With this in mind we can only make predictions on smaller storms as to how badly solar flares will affect our satellites, and with these smaller flares being taken into account some of the predicted damage may not be so great. It’s understandable that some satellites may go down but newer ones should have precautions incase of these flares. So for how this will affect us we can initally say that the impact may not be that great but may mess up our satellite tv or our sat navs forcing us to use a map!

2. Communications

Following on from the effects caused by solar flares to satellites a major associated issue that could arise under the events of large scale solar flares is that of our communication systems ‘going down’. A loss of satellite communications can eliminate some pathways to communication around the world and the communications received as a result of satellite TV. Large solar flares and the stream of charged particles that emanate from them can also have an effect with long range radiowave communication as well. Communications that use the atmosphere to transmit over large distances can sufffer large amounts of interference due to extra charges and energy in the atmosphere. This also can apply to mobile phone communications that use microwaves to transmit data. It was also reported in the solar maximum in the 1970s that long range telephone communications were brought down by a solar flare in Illinois, US showing the effect that flares can have on facilities that are based on earth as well as in space.

3. Electrical Grids

In the last solar maximum, Quebec in Canada was hit pretty bad by a solar flare and as a result six million of it’s inhabitants were plunged into darkness as the power grids were affected. Understandably back in the 80s this caused a problem however it can be expected that if this occurred in the next solar maximum it will affect us a lot more due to our greater reliance on electricity in a gadget driven world. This will cause turmoil not only in the home but potentially businesses as well, as computer systems and communication lines go down due to a loss of power. This overall can also have a major affect on the economy.

 

…and finally a good one

 

4. Aurora

Aurora (otherwise known as Northern/Southern Lights) occur as charged particles emitted from the surface of the sun come into contact with the magnetic field around the Earth. They get trapped in regions known as the Van Allen belts which ‘focus’ particles towards the poles leading to the areas in Scandinavia for example where the Aurora occurr. The charged particles interact with Oxygen and Nitrogen in the atmosphere which through excitation and relaxation of molecules/atoms lead to the characeristic red and green glow of the Aurora. With increased solar activity comes increased Aurora ativity which when intense can happen further south, as a result more will have the opportunity to see this sight.

 

All in all, we will not be wiped out by a solar flare in the coming years as some would like to believe, however it is aparent that some measures need to be taken in order to lessen any damage to technology and the economy on Earth. Measures have already been taken to protect satellites so hopefully with measures taken to protect power grids the coming storm will cause us less trouble than it has the potential to deal out. And even if we are all plunged into darkness, at least light pollution won’t get in the way of the Aurora!

 

http://www.youtube.com/watch?v=GX_hoYYR3E4 there’s also an excuse to post a song I like called Solarwinds

What? A molecule that enables hearing

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By Kathryn Vaughan

Researchers at the University of Sheffield have identified a molecule that underlies mechanisms of hearing loss and deafness.

In the inner ear ‘cochlear hair cells’ are responsible for receiving sound as sensory information before it can be converted into electrical nerve signals to be sent to the brain, and these hair cells mature during embryonic development. To examine the mechanisms that regulate cochlear hair cell maturation, researchers led by Walter Marcotti from the University of Sheffield have investigated the role of a molecule named miR-96. The molecule miR-96 is a microRNA, a short genetic sequence that regulates the expression of a range of genes, and is itself highly expressed in developing cochlear hair cells.

Mice that do not express miR-96, referred to as ‘knockouts’, were compared with control mice that do express miR-96. To examine differences in structure, hair cells from the two groups of mice were observed under a microscope and measurements were taken of both cell length and sensitivity to a neurotransmitter. By placing a speaker 20cm directly in front of each mouse and recording a ‘Preyer reflex’, whereby a mouse flicks its ear in the direction of sound, the researchers also measured auditory brainstem responses, which reflect the activity of the hair cell.

The researchers found that the cochlear hair cells of the mice that do not express miR-96 were thinner, shorter in length and more immature when compared to hair cells of control mice, identifying a role for miR-96 in the maturation of cochlear hair cells. To investigate the activity of the hair cells by measuring the auditory brainstem responses, the knockout mice could not be used since they have no auditory response at all. Instead, mice with limited miR-96 expression were compared with control mice and were found to be less responsive, indicating a defect in their hearing due to the limited miR-96 expression.

Measurements were also recorded to examine the sensitivity of hair cells to a neurotransmitter called acetylcholine. Acetylcholine is a molecule released from nerve endings and can act upon cochlear hair cells to initiate the conversion of an auditory response into an electrical nerve signal. Sensitivity to acetylcholine was reduced in knockout mice whilst control mice responded as usual, implicating miR-96 in hair cell activity.

These results indicate that in the maturation of cochlear hair cells, which is vital for the fundamentals of hearing, miR-96 plays an essential role. By understanding these mechanisms the researchers propose that the research “could provide us with clues to help develop therapies to ameliorate the effects associated with nonsyndromic progressive hearing loss”.

Cochlear hair cells in a Guinea Pig

 References:

Kuhn et al (2011) miR-96 regulates the progression of differentiation in mammalian cochlear inner and outer hair cells. Proc Natl Acad Sci USA, 108 (6), 2355-2360.

The paper can be found at:

http://www.pnas.org/content/108/6/2355.full.pdf+html

Doing chemistry in reverse

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So, amides. If you’re any kind of a chemist, these are your bread and butter. Making a bond between an amine and a carboxylic acid to form an amide is one of the first reactions any chemistry student ever learns about. And even if you’re not a chemist, if I tell you that the amide bond is also called the peptide bond perhaps you might start to get interested; that’s right, the very amino acids that make up the life-giving proteins in out bodies are linked together by this vital type of bond.

Here’s how a traditional amide bond forming reaction might be written out:

In this reaction the amine has a lone pair of electrons which flow towards the positively charged carboxylic acid carbon. Water is eleimnated and the amide is formed.

This reaction is literally great, becasue no matter what groups are attached to the components (i.e. the groups I’ve called ‘R’) they can be stitched togethr with this neat condensation (so called because water is given out during the reaction).

The Science of Cocktails

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What happens when you bring together a thirsty and fun-loving group of the public and a chemist with a deep interest in alcoholic beverages together? Answer: …A night many might not remember, but nevertheless, utterly intriguing and fun! The science of Cocktails event took place last Friday, all punters leaving happy!

75 people who came dressed to impress, packed in to the Common Room in University House, situated in the Students’ Union and learnt about where alcohol comes from, what gives vodka and whiskey their tastes, how to get the most out of your spirits, and how to make your own cocktail combinations… Though I thought it was all going to go downhill when the first slide of the presentation stated: ‘All alcohol is poisonous’. Quite true, we don’t condone binge drinking, but everything in moderation! The night ended, quite appropriately, on a look at what hangovers are, and how to avoid them.

Throughout the night, attendees were invited to taste, smell and mix drinks for themselves, starting the night off with a fizz in the shape of a lovely champagne and brandy-based cocktail, comparing vodkas, whiskey tasting, making a screwdriver, ending the night on a proper Irish coffee. The hangover advice being handy… I’m told…

There’s no doubt that our rather dapper host for the night, Noel Jackson, trained chemist, Head of Education and resident mixologist from the Centre for Life up in Newcastle, knew his stuff! Having come up with the Cocktail Hour after thinking of ways to engage 18-30s with science. The answer seemed to be sex, drugs and rock’n'roll! Aside from the insight in to the chemistry of alcohol production for example (did you know your cheap vodka comes from oil refinery!), there were countless insights in to the history, aetiology, sociology and geography of cocktails and various spirits! An extremely eye-opening and sometimes mind-blowing experience.

Organised by our ever-wonderful secretary Tacita Nye, and supported by the committee and our volunteers, it went fantastically, so I’d like to take the opportunity to thank Tacita and Noel for making it so enjoyable, and all the hard-work that our volunteers did to make it the success it was.

“The evening was a perfect balance of science and everyone’s favourite pastime – drinking!” Tacita said in summary of the night, her favourite part was when attendees mixed up their own screwdrivers, “there really were some interesting combinations!”

One of our past committee members made the trip up from London and broadcast this via twitter: 

BekiHill
Science of cocktails w/ @scibrainwaves was great, but definitely feeling a bit worse for wear now!

Jon Banks, a self-confessed whiskey lover who attended the event, left us this message on our Facebook:

“Thanks Brainwaves for an awesome night of science and cocktails! I learned all about distilling, hangovers, and why you should always drink scotch with water! I even remember some of it!”

We also tested out our budding mixologists’ knowledge by doing the Big Cocktail Quiz – three lucky winners took home some wine and some guides and recipe books on cocktails, to carry on the fun when they got home.

This was our first ever adult-only night. Usually we’re out and about ranting and raving about the awesomeness of science to anyone who will listen! We’re really pleased it was so successful, in fact, watch this space for a botanics of Gin night! Whilst we had to charge entry for this event to cover the costs of alcohol and so on, we were extremely grateful to all the donations that people generously gave us so that we can continue to put on free events, for children, families and, well, everyone!

Thanks to Ron Adams for taking pictures on the night, and some of the attendees; Adam Dobson, Paul Clarkin and Beany Rosic, for sending in their pics!