Bang! Science Magazine, Issue 13

Bang!

The Danger Issue Oxford Science Magazine 13th Edition Hilary Term 2013

CHANGE THEIR LIVES AND CHANGE YOURS Just 62% of young people eligible for free school meals get a Science GCSE grade A*-C* Take up the challenge, get involved, Teach First.

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"Every day s somet hing happen to remind me that I am making a difference” Lena Khudeza, ‘09 Taught: Science, West Midlands

Now: Retail Bank Manager, HSBC

Contents

danger section

3 4 5 6 7 8 9 10

20 22 24 25 26 28

Editorial News Bang! Explains: The Higgs Boson The Science of Emotion War of the Sexes Serotonin’s Role The Dream Answer The DAWN Mission 11 Mathematicians at War 12 Encrypting Messages 14 The Pursuit of Poisons 16 Puppetmaster Parasites 18 Bang! Talks To: Prof. Sir Richard Peto The Patent Cliff The Missing Folds Socialising Ants Like Mother, Like Daughter Saving the Cute Bang! Crossword

Staff Editors in Chief Kathryn Boast & Sofia Hauck Print Editor Richard Millar Online Editor Matthew Warren News Editor Sophie McManus Broadcast Editor Laura Soul Sub Editors Sam Binding, Sarah McCraw, Sophie McManus, Lauren Passby, Anna Sigurdsson & Iona Twaddell

Business Manager Paulin Shek Business Team Mahnoor Naeem & Gareth Watson Publicity Manager Mao Isobe Published by Oxford Student Publications Limited Chairman Max Bossino Managing Director Stephanie Smith Directors Morgan Norris-Grey, Nupur Takwale, Rohan Sakhrani, Sophie Jamieson & Douglas Sloan

Creative Manager Iona Richards Creative Team Ruby Byrne & Camille Fenton Artists Chloe Tuck, Thao Do, Natasha Lewis, Aparna Ghosh, Hope Simpson, April Hills, Jade Barrett, Joy Aston, Haneesh Sidhu & Annabel Forbes-Cockell

Printed by Mortons Print Limited Copyright Bang! 2013

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Cover by Natasha Lewis and Sofia Hauck.

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Editorial “As soon as there is life, there is danger.”

— Ralph Waldo Emerson We live in a dangerous world, and it can seem like everything is out to get us. From parasites that want to control our every move to natural disasters

and work out how to protect ourselves and this amazing world we live in.

Kathryn & Sofia Editors Art by Aparna Ghosh.

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News Inflammation and schizophrenia linked published in Neuropsychopharmacology

Eat your greens!

delusions and a desire for isolation.

An Oxford study published in the American Journal of Clinical Nutrition has revealed that lowered risk of heart disease.

Heart disease is deadly in the developed world: 65,000 deaths This study is the largest of its

the data analysis. 45,000 people vegetarian, an unusually high relative risk.

Closest Earth-like planet found On the 6th

hospital diagnoses. Upon analysis of the results, vegetarians were of heart disease.

orbiting a red dwarf star.

work, Professor Tim Key, “The of heart disease in vegetarians is about a third lower than in Of the 95, three are a similar size to Earth. Furthermore, these three planets

Something to think about whilst

Sophie McManus is a 2nd year Biomedical Sciences student at Magdalen College.

Art by Iona Richards.

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Bang! Explains: The Higgs Boson Been confused lately by science news? Let us help!

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n July 2012, the scientists working at the Large Hadron Collider (LHC) announced the discovery of a Higgs-like particle, to world-wide acclaim. Half a year on, what do we now know about this elusive particle and how has the discovery changed our understanding of the world?

the four fundamental forces in the Universe: electromagnetism, the strong nuclear force and the weak nuclear force. All the particles included in the theory have been discovered by particle physicists, with the Higgs jigsaw.

Physicists had many hopes for what

The Higgs particle is the embodiment

tell us about physics beyond the Standard Model, which is arguably one of the most successful theories in Physics. But it was the clues the Higgs

for giving particles mass, and it

phenomena in physics, those that the

in high energy collisions in the LHC, the Higgs particle quickly decays into other fundamental particles. These decay rates are then measured by detectors surrounding the collision site and compared to the theoretical values predicted from the Standard Model. As far as we can currently tell, the observed decay rates seem to correspond very well with those predicted by the Standard Model.

including dark matter and gravity, that However, from the evidence so far, it seems that the Higgs does not actually what does this mean for physics beyond the Standard Model?

The Standard Model is a theory properties of all the fundamental particles that we have discovered in the Universe to date. Its particles range from quarks and electrons that make up atoms, to photons and other bosons — particles that convey the forces that hold everything together.

This theory encompasses three of

mass while photons (light particles)

However there is a problem with the Standard Model, and we know it must be incomplete. There are observed phenomena in physics that it cannot include the fourth and most famous fundamental force, gravity – it has no

coherent theory of the Universe. Also name given to 84% of the mass in the Universe that seems to not interact with light.

There are several theories in particle include super-symmetry (which postulates super heavy versions of each particle in the Standard Model), Theorists had hoped the search for the Higgs and its discovery would have helped point to a direction in which research could be focused to discovery of a Standard Model Higgs tantalizing signs, so far, in favour of any of these candidate theories. One of the hopes was that, along with the discovery of the Higgs, the search at that were not predicted by the Standard Model but were predicted by some versions of super-symmetry. At current collider energies this is not the case, but when the LHC is turned up to full power in 2014 there will be new symmetry.

This discovery means that almost every aspect of the Standard Model has been proven correct, making it one of the most successful theories of all time. However, there has been and how to solve the great mysteries of modern physics. Nevertheless we have only begun to skim the surface has produced, and in the future the LHC will be turned up to full power, potentially providing a new realm of the answers to many of our questions.

Andrew Yeomans is a 4th year Physics student at Trinity College.

Art by Thao Do.

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The Science of Emotion How our genes affect our moments of grief and joy

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hile we are all aware of the role genes play in shaping us, few are aware of the extent to which they could determine how we interact with each other and the world around us. Emotion has been puzzling psychologists for centuries, but biologists have found a Darwinian answer to the problem by suggesting that humans experience emotions because of the evolutionary advantages they provide.

Although our genes are unable to control our consciousness in real-time, they still have a mechanism to give our brains some basic instructions to survive and thrive in an ever-changing environment.

Genes cannot supply an emotion or programmed behavioural response to every event; instead they provide some basic instincts for us to follow, which elicit evolutionarily favourable reactions. Like a computer chess programme — in which all possible combinations of moves cannot be individually instructed for but the computer is given the basic information and guidance on how to play — genetics has enabled thousands of events to be responded to by relatively few emotions, such as grief, joy, anger and love.

Genes cannot explicitly instruct us to ensure their survival in a new generation, but what they can do via hormones and neuronal interactions is use emotions as a carrot-and-stick method of controlling our behaviour.

For example, many people enjoy eating sweet things

and consuming this food gives us some sort of reward, so we repeat the process, unaware of what is actually going on in our brains and bodies. Unfortunately, we have not yet evolved a threshold point at which we are signalled to stop eating sweet foods, leading (at least in part) to the obesity epidemics sweeping developed

is a great resource to our genes.

Genes only have a certain amount of time to be successfully passed on to future generations, so it should be spent wisely. Investing time in a well and good, but if that friend dies, is essentially wasted. The grief that follows is an attempt on the part of

discourages us from eating potentially unsafe substances such as rotten fruit.”

“Disgust countries, and to the doubling of the fraction of the world’s population living with diabetes since 1980. us from eating potentially unsafe substances such as rotten fruit or meat that may contain harmful bacteria or parasites. In such a case, the reaction to the visual and olfactory stimuli isn’t just an emotional one, but a physical one too. Often when presented with an unappetising specimen, the corners of a person’s mouth will turn down making it Grief is an interesting emotion, often so severe as to become debilitating.

To understand why we feel grief, it is important to remember that time

our genes to reprimand us for a poor decision – the human we’ve chosen to invest in has failed as a resource, and our choice of ally should be more carefully considered next time.

A much more powerful form of grief occurs between a parent and child. In species with a high degree of parental care, a large amount of the mother’s time and energy is taken up caring the very least some of her energy and food is used in making the egg. The if it dies. Essentially, the genes are punishing the organism for doing something wrong, by investing their a mistake.

Our genetic makeup can indirectly responses in a variety of subtle ways. From sensations of joy and happiness to experiencing anger, loneliness and frustration, our genes may have more of an actions than we would care to believe.

molecules. Although in some modern countries this has been taken to a damaging extreme, consuming these foods gives the body lots of energy for use and storage, which is advantageous to the consumer. Therefore these foods taste nice, and we enjoy

Ellen Foley-Williams is a 1st year Biomedical Sciences student at Wadham College.

Art by April Hills.

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War of the Sexes

Strange romance lives on in the natural world

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he ultimate goal for all organisms on earth is procreation, and after 4 billion years of practice some bizarre and often slightly disturbing adaptations have arisen. While the reasons for the evolution of sex are still hotly debated, it is certain that many organisms invest a great deal of time and energy in securing an appropriate partner. Unfortunately the process is not always an amicable one.

Pseudobiceros hancockanus is an small, squishy creature with an orange band and a purple fringe that looks

Following traumatic insemination, the to the recipient’s ovaries, resulting in fertilisation.

Female spiders possess a pouch called a spermatheca, which allows them to store sperm for long periods of time single encounter. This also means that each mating opportunity is extremely valuable to male spiders. This strong sexual competition has led to many instances of mate-guarding and sperm plugs. One species of garden spider,

romantic gestures are permeated “These by a culture of backstabbing.” as though a toddler crafted it out of Play Doh and coloured it in. Inhabiting the idyllic coral reef ecosystems of Melanesia, South East Asia and East Africa, it would be easy to assume that this widespread denizen of the ocean does not have a dark side. Until it starts penis-fencing.

Sexual competition is ubiquitous in nature, but P. hancockanus deals with it in a spectacular fashion. The their prospective partners using their sharpened two-headed penises, opponent. The victor then ejaculates, injecting sperm into the loser. The recipient must then assume the role of the mother and bear the energetic expense of developing the insemination’ (that is, the practice of insemination by puncturing the recipient’s body as opposed to via sex organs) is surprisingly common and widespread among invertebrates. Their open circulatory system allows body

Argiope aurantia, even dies upon completion of the deed. Minutes after insertion, his heartbeat stops and the corpse acts as a makeshift plug.

That said, Harpactea sadistica is the king of appalling spider sex. What starts with a dance and an embrace devolves into the male driving itself directly through the female’s ventral side using the needle-sharp tip of its penis (called an embolus) and ejaculating directly into her body cavity. The male repeats the process multiple times, alternating between his two penises. This method conveniently bypasses the female’s spermatheca and thus overrides any choice she may have in which male fertilises her eggs. However, the process is not completely one-sided; not only do females appear to be unharmed by the procedure, but in a grim twist of advantageous for her to choose the males that are best at this gruesome form of mating,

this, for better or for worse, includes

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since their abilities may be conferred to their sons. Perhaps masochistica would be a more appropriate species epithet.

Bed bugs have partly tamed the process of traumatic insemination by evolving sperm-storage and selection organs at the new site of penetration, external genitalia.

Aside from these depraved shenanigans, are there examples of the opposite - males instead being exemplary lovers? Many animals, from shrikes to bush crickets, woo their mates with nuptial gifts: items of food or inedible tokens that either sway the female’s choice, or occupy her for long enough to mate with.

Some spiders go even further, giftwrapping their contributions, and Paratrechalea ornata even includes a sweet-smelling pheromone in the silk lining. Unfortunately, these romantic gestures are permeated by a culture of backstabbing. Often females will try to steal gifts and cut short the copulation.

Nursery web spider (Pisaura mirabilis ) males are equally devious and will wrap worthless items and present them to their chosen victim, duping them into sex. By the time it has been unwrapped, it is too late.

And they say romance is dead.

Tom Williams is a 3rd year Biological Sciences student at St. Anne’s College.

Art by Haneesh Sidhu.

Serotonin’s Role

Neurotransmitters for punishment and reward

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opularly regarded as a “happy brain chemical”, serotonin is not far from becoming a household name. a chemical that brings about positive moods is disregarded by many neuroscientists, who claim this to be topic of research. This might sound like a common case of academic snobbery, but in fact there is much eye. category of brain chemicals that allow electrical signals to cross the tiny gaps these neurotransmitters is dopamine, which, according to popular science, detects the presence of rewards.

However, this view is out of line with dopamine release signals the presence arrival of a reward becomes more reallocated from the reward to cues in the environment which are associated with the reward’s arrival; this allows us to anticipate the reward. So when increase, yet as the thrill of the subsequent rides, less dopamine is released. Instead dopamine levels rise in response to cues associated with the ride, such as the theme park’s logo shown on an advert.

Neuroscientists are now drawing a parallel between the precise functions of dopamine and serotonin. It is believed that one purpose of serotonin punishments and the cues associated with the onset of such punishments.

Imagine that a rat is dropped into a cage containing one plain white area and another striped black-and-white area. Upon entering the striped area shock — this incident and any future sightings of black-and-white stripes would, according to this theory, increase serotonin levels in the rat, as it is associated with the punishment In this sense, the function of serotonin opposes the function of

people with low serotonin levels may be vulnerable to depression because unpredictable fashion. The resultant belief that they cannot control life situations is often interpreted by cognitive bias. Yet according to the latest view of serotonin release, this feeling of hopelessness may be more in line with reality than we

is associated with a positive “S erotonin mood because it allows us to predict when negative events are likely to occur.” the need to avoid an upcoming punishment, whereas dopamine release indicates the need to approach a stimulus associated with a reward.

This follows the notion that serotonin mediates the inhibition of actions, for a punishment-associated cue.

This new theory, however, poses a question for the popular view of the traditional view of it producing positive moods? Low levels of serotonin are characteristic of people Moreover, drugs known as serotonin reuptake inhibitors are widely used to treat depression by increasing the duration for which serotonin remains active in gaps between brain cells.

One way to reconcile these two views is to argue that serotonin is associated with a positive mood because it allows us to predict when negative events are likely to occur. In contrast,

of depression, given that serotonin is not available to help such people anticipate upcoming, unpleasant events from cues in their environment.

As a result, they do not have the neural chance to steer clear of such negative events.

Once the popular view of serotonin catches up with the latest research, perhaps serotonin and dopamine ‘shock neurotransmitter’ and ‘surprise neurotransmitter’. This should help which have been tied in the popular perception of serotonin; though by the time a new nickname takes hold, function may have changed again!

Robert Blakey is a 2nd year Experimental Psychology student at St. Catherine’s College.

Art by Chloe Tuck.

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The Dream Answer Why do we need sleep?

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he nature of dreams has been a topic of fascination for thousands

analysis dates back to 3000 B.C., written on clay slabs in the ancient realm of Mesopotamia. Various explanations of dreaming have years, including contact with the dead, messages from gods, and premonitions of the future, but as yet the truth remains elusive.

Dreams are most numerous and vivid during rapid-eye movement (REM) sleep, in which the eyes move quickly and brain activity is akin to during waking hours. REM lasts for about two hours each night. The rest is spent in a deeper form of sleep called ‘slow wave sleep’ when brain function is diminished. Individual dreams can last from a few seconds to twenty minutes and during a typical lifespan we spend about six years dreaming.

Are dreams just an epiphenomenon?

Some dream theorists believe that dreams are simply a necessary byproduct of sleeping. When we are asleep our senses dull as neuronal activity is suppressed in sensory processing areas. The absence of external stimulation is suggested to cause spontaneous neural resonance patterns which are interpreted as dreams. This idea is supported by the fact that damage to the

parietal cortex, an area of the brain important for sensory integration, can cause people to become incapable of dreaming.

However, this theory cannot explain why animals exert a considerable example, ungulates such as horses vulnerable position of sitting to achieve REM sleep — in mammals REM is accompanied by muscle relaxation, which prevents movement. What is more, baby mammals put themselves

awaken. The results indicated that REM sleep was important for forming new memories as the REM-deprived rats were unable to learn to avoid noxious stimuli.

The famed psychic Edgar Cayce once said, “Dreams are today’s answers to tomorrow’s questions.” Indeed, there is a current theory suggesting that, rather than memory consolidation, dreams are more likely to be used to prepare us for future sensory and motor demands. This theory

leading theory about dream function is that “Another they are a mechanism for memory formation.” in considerable predation danger by indulging in extended periods of REM. Therefore it would seem there must be a function to dreaming which has prevented it from being eliminated by natural selection.

Another leading theory about dream function is that dreams are a mechanism for memory formation. of REM sleep deprivation have been conducted on rats. The rats were placed on a stand on which they could remain whilst in slow wave sleep, however, when they passed into REM sleep the muscle relaxation would

would suggest that the reason the rats were unable to avoid noxious stimuli in the experiment was because they didn’t receive the necessary preparatory signals from REM sleep.

This may explain why foetuses and young babies experience such a comparatively large amount of REM sleep as it could help them prepare for physical and mental challenges such as speaking, crawling and walking.

The future of dream research looks to be an increasingly sophisticated one. New methods of matching EEG signals to dream reports are currently being implemented into research studies. In addition, new technology is being investigated using mild electric currents delivered to the brain to alter dreams, which if successful, may be a vital tool in shedding light on the elusive dream state. As these continually improves it seems like we that long-awaited dream answer.

Annabelle Painter is a 1st year graduate student of Medicine at Worcester College.

Art by Thao Do.

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The DAWN Mission

Second star to the right, and straight on ’til morning

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hen the interplanetary probe DAWN embarked on its 8-year odyssey through the Solar System in 2007 no one anticipated the magnitude of information this mission would reveal. As DAWN set speculated about what might be uncovered. This mission has brought our view of the asteroid belt into focus and has revealed that asteroids planets themselves.

The DAWN mission is NASA’s ninth within our Solar System to focus on key unanswered questions. The objectives of the DAWN mission are to investigate the planetaryformation processes and conditions present in the early Solar System. This knowledge will enable us to better understand how the planets and their building blocks formed and evolved over time.

DAWN will visit the two largest

planetary evolution process. Vesta and Ceres provide a snapshot in time of a stage in the formation of planetary building blocks and preserve a record of Solar System conditions from the formation era.

impact basins on Vesta’s surface. These basins have

Although both asteroids have remained fairly intact throughout

the Vestoids (5-km sized fragments of material similar to Vesta and the

end there. Vesta segregated into a

which themselves supply a mechanism for the delivery of this material to the Earth. The impact basins show

few million years after Solar System formation. We gain direct chemical and age information about Vesta from a group of meteorites which volcanic and igneous rocks we see on Earth.

Ceres is a wet asteroid which has not undergone interior segregation.

Ceres may contain a rocky core; carbonates and other icy and hydrated Ceres cannot directly be linked to any meteorites found on Earth.

Highly specialised equipment has

the mass of the asteroid belt itself.

Vesta and Ceres are protoplanets whose growth was terminated early ideal candidates for us to study the

Visible and Infrared Spectrometer (VIR) and a Gamma Ray and Neutron Spectrometer (GRaND).

Combining the measurements from all of this equipment will provide a structural image of the interior and exterior of these two bodies.

High resolution imaging has already unveiled tantalising new details

granting Vesta the honour of having the highest mountain in the Solar System – even larger than Olympus Mons on Mars and over double the height of Mount Everest! A further exciting result from the DAWN mission is the presence of hydrated to originate from collisions during the formation of the asteroid. The presence of these minerals allows us to investigate the origin of water in the Solar System and the delivery including the Earth.

DAWN has recently bid Vesta the next part of its adventure by starting the 38 million mile voyage the Sun. However this is not the last turned out to be much more similar to the Earth than previously thought.

We have uncovered a treasure trove of information which needs to be carefully sorted through and investigated. Combining all of the data from this mission will allow new paradigms to be developed and what may be revealed about Ceres – so watch this space!

Helen Ashcroft is reading for a DPhil in Experimental Petrology at St. Anne’s College.

Art by Thao Do.

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Mathematicians at War Cold, hard numbers for critical times

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he importance of mathematics in breaking the Enigma Code during Second World War is well known.

Its contribution to optimising military tactics and organisation through Operations Research has never enjoyed the same recognition, despite involving a thousand men and women, some of them very eminent scientists.

Military commanders were generally enthusiastic in their adoption of new technology, but less inclined to submit their decisions to quantitative analysis. Patrick Blackett, wartime Director of Naval Operational Research and future Nobel Laureate, complained that too much study had been applied to producing new ‘gadgets’, and too little to using approach, and his work improving coordination between radar operators and anti-aircraft installations reduced bomber shot down from 20,000 at the onset of the Blitz to 4,000 by its conclusion.

Faced with a vastly better resourced adversary at the beginning of the Second World War, British leaders turned to mathematicians and other scientists to ensure that their limited resources were being used best-selling war memoirs, but given Royal Navy until at least 1944 were duds it was a vital job! Other areas, ranging from aircraft maintenance schedules to troop movements, came under scrutiny, as the waging of war was made quantitative to an unprecedented degree.

Perhaps the greatest success of operations research, however, was in the battle against U-boats in the Atlantic. An impressive analysis of the theory underlying attacks on merchant shipping was completed in 1917. Described as “An account

of the Trojan War written by Euclid”, unfortunately it was so virtually unread, and was destroyed, unused, in 1939 on grounds of obsolescence!

The reference to Euclid suggests that this lost work used the same geometric reasoning which had to be developed from scratch during the Second World War. Statistics showed the main factor determining the survival odds of a merchant ship was the number of escorts nearby.

Merchant ships in convoy are encircled by warships; doubling the circle’s radius quadruples the area, so large convoys were seen as the best way to protect shipping. The size of even the largest convoy pales in comparison to that of the ocean, so they were hardly more likely to be found than a single ship. Having so much tonnage arriving at once challenged the infrastructures of the receiving ports, but was preferable to the gruelling casualty rates incurred previously.

Complementary to convoying was the development of better U-boat hunting tactics. Initially, aircraft rarely spotted submarines, and even when they did only two or three attacks in every hundred succeeded in sinking the target. A back-of-the-envelope calculation, drawing on estimates of U-boat numbers from intelligence sources, convinced Blackett that the planes should be encountering far more, and that the vessels must be spotting the aircraft in time to submerge undetected (U-boats travelled much slower underwater, and so tended to stay on the surface unless a threat was observed). Having

improved, the number of sightings rocketed.

Furthermore, he had the depth charges carried by the planes reset to detonate at 25 feet below sea level rather than 100. The latter had been determined as the average depth a submarine would reach when evading a bombing run, but Blackett reasoned that such submarines would have moved too far from their surface position to be targeted accurately.

The submarines at 25 feet might be rarer, but they could be located fairly reliably. The success rate of attacks quadrupled overnight.

Following the end of the Second World War, the importance of mathematical and statistical studies was taken onboard for modern warfare, marking a change from relying almost solely on experience and intuition. Although mathematics had previously been applied to military questions, the Second World War marked the turning point for the waging of war becoming a quantitative endeavour.

Paul Richard Taylor is reading for a DPhil in Systems Biology at New College.

Art by Natasha Lewis.

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Encrypting Messages

Using prime numbers and quantum mechanics to keep data safe

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rom replying your emails to Internet banking, we are always passing around our personal data.

Cryptography is used to make these communications secure; without it there would be no such thing as information privacy.

As cryptography is the only barrier the bad guys, it’s worth knowing and caring about. Let’s explain the basics of cryptography by telling a story about Alice, Bob and Eve. They could represent your computer, your bank and a hacker respectively. Suppose message to Bob over a public channel an encryption key – a special type of code - to turn her original message, which is in ‘plaintext’, into a coded message known as ciphertext. Upon

receiving the ciphertext from Alice, Bob will use a decryption key to turn it back into the original message.

There are two types of encryption systems: Common Key Cryptography (CKC) and Public Key Cryptography (PKC). Common Key Cryptography is also known as Symmetric Key Cryptography because the encryption and decryption keys are identical.

into ciphertext. Upon receiving Alice’s ciphertext, Bob can use the decryption key - which is known only to him - to retrieve the plaintext.

In contrast to CKC, which uses XOR for the encryption and decryption, PKC uses ‘one-way mathematical functions’, which are easy to carry out A notable such function is prime

Alice wants to send a confidential “S uppose message to Bob over a public channel.”

It uses a logical operation called ‘exclusive or’ (XOR) that gives a value of one when its two inputs (the message and the encryption key)

decomposition, whereby an integer is broken down into a string of prime numbers that will multiply together to produce it. While it is easy to multiply

same. So suppose Alice has a simple plaintext message 0011 and her encryption key is 1010. Carrying out the XOR operation by comparing the two digit-by-digit gives the ciphertext 1001. When Bob receives this, all he has to do is carry out XOR again with the decryption key (which is the same as Alice’s encryption key) to retrieve the original message.

together, if we only know the product

But CKC is inconvenient because Alice somehow has to let Bob know her key securely. If she tries to send Bob her key by carrying out another CKC with a second key, she still needs to let Bob know her second key somehow, and so on. Ultimately, the only way out is for Alice to give Bob her key by some other secure means, such as meeting in person. But no such problem exists in the alternative encryption system, Public Key Cryptography.

PKC is also called Asymmetric Key Cryptography because the encryption This time it is not Alice, the sender, but Bob, the receiver, who needs to an encryption key to the public. Once Alice gets hold of the encryption key, she will use it to turn her plaintext

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the two primes. This is currently computationally impossible because the only known way of achieving this would take longer than the age of the Universe.

To generate the encryption key to be issued to the public, Bob comes up with two arbitrary large prime numbers and calculates their determines his encryption key from the two primes. He also calculates the decryption key from the encryption key and the primes via another formula. Now that he has all he needs, he keeps the decryption key to himself, but releases the encryption key and the product of the primes.

Once Alice gets these two from open public sources, she can feed them into to turn her plaintext into ciphertext.

When Bob receives Alice’s ciphertext, he can use his decryption key and the product to retrieve her plaintext, formula.

Any supposed eavesdropper, known in this story as Eve, may try to eavesdrop Alice’s message by two

PT

Public (Asymmetric) Key Cryptography

PT

CT

trapdoor

Common (Symmetric) Key Cryptography

CT

Ronald Li is a 4th year student of Physics at Keble College.

Art by April Hills.

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The Pursuit of Poisons A story of killers, victims and forensics

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he use of poison has been documented as far back as 2500 B.C. in Greek mythology, 3000 B.C. in Egypt, and even as early as 4500 B.C., when Sumerians worshipped a goddess of poisons. Archaeological evidence in the form of grooves

communities, the knowledge of such injurious substances was restricted to certain members, but as they became more widely used — medically, for example — and accessible, they rose in the favour of people with a penchant for murder.

The administration of poison was considered as being planned in cold blood and resulting in extended anguish, leading the playwright John Fletcher to refer to it as ‘the coward’s weapon’. Nevertheless, it has been turned into a form of art more so than almost any other tool of killing. Among several popular options, four poisons of historic interest are arsenic, hemlock, atropine, and cyanide.

Arsenic Arsenic disrupts the respiratory pathway, preventing the production of the energy storage molecule adenosine triphosphate (ATP) and leading to organ failure. With symptoms that imitate those of chronic th century, an Arabian chemist produced a tasteless, odourless derivative of arsenic that provided poisoners with their ideal instrument. th

th

centuries, the Borgia dynasty infamously eliminated several rival families with the help of arsenic, accumulating against poisoning, though this did little to hinder the alarming rate at which incidences of poisoning continued to rise. Arsenic later became known as a lady’s poison, as women would carry it to make their complexions fairer (through the constriction of blood vessels).

Hemlock Hemlock disrupts receptor activity in the nervous system, causing muscular paralysis followed by death from failure of the ventilation system. Throughout this, the victim used by the Ancient Greeks, both for sanctioned suicides and capital punishment.

The philosopher Socrates, after being convicted for impiety, met his death by died after drinking a mixture of poisons containing hemlock. Perhaps this was developed from one of the venomous cocktails she is rumoured to have tested on her maidservants.

Atropine Atropine is derived from deadly nightshade (or belladonna, ‘beautiful woman’ in another chemical that blocks receptors in the nervous system, disrupting widespread physiological functions, including heart rate regulation. Shakespeare’s Macbeth used atropine to wipe out an entire army of opponents.

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Cyanide While cyanide can be found everywhere, it wasn’t until a Swedish chemist found a way to distil hydrogen cyanide that it the heart and nervous system.

sends astronauts on missions with cyanide pills in case they cannot return to Earth, though this has been debated.

In the recent James Bond movie, Skyfall, the villain Silva had tried to kill himself by breaking one of these cyanide capsules but the attempt failed, destroying his teeth and leaving part of his face deformed. This is have been cases of unsuccessful suicide attempts with cyanide pills, Silva’s injuries in particular seem unlikely.

Speculations suggest the pill may have been unconventional, that his captors treated him with antidotes, or more likely, that the injuries are just the consequence of artistic license. became the last Tsarina’s advisor), whose killers attempted to poison him by lacing his cakes and wine with cyanide. However, even after shooting, clubbing, and throwing him into the river, it was miraculously only in stomach acidity was too low to release a lethal amount of hydrogen cyanide.

Poisons were often selected based on how easy they were to get hold of, meaning preferences changed with the times and the activities of communities. to discreetly grow a towering bush of deadly nightshade. Hemlock went out of style for similar reasons.

Many poisons were initially administered as medicines. This brought them to the attention of the public, could enable them to be acquired from apothecaries, and allowed plausible deniability when found in someone’s possession following a murder. Even today, arsenic can be used against cancer and atropine by eye doctors. Hemlock may have once been used by physicians as a sedative. Some

is a medicine, and a medicine in a large dose is a poison.”

the use of poisons more regulated, and have facilitated the tracing of poisons in criminal cases. Still, new poisons rise up from conventional medical drugs (e.g. insulin), or from slightly more unconventional sources (e.g. antifreeze). between the employers and analysers of poisons.

Ayesha Sengupta is reading for an MSc in Neuroscience at Queen’s College.

Art by Thao Do and Iona Richards.

15

Puppetmaster Parasites

Some invaders change the hosts’ behaviour to suit their needs

C

Sacculina

Alien

filmakers were “Alien’s inspired by real parasites.”

Alien

Ampulex compressa

Toxoplasma gondii

Ampulex

16

Ampulex compressa

meremithid nematode

which it must reach to reproduce sexually. However, it often spends an intermediate period in humans and in rats – an estimated 35% of the rat population is infected with the parasite. Studies from the University of Oxford and Imperial College London have found that infected rats no longer display an innate aversion to the scent of their feline predator, with some infected rats becoming fatally attracted to it!

mites have been found to spend more time courting females. The greater the parasite burden the more time the males spend courting. This might seem like a great example of behaviour

transfer the parasite to its main host, the cat, they still display neurological infected. Scientists have found that infected humans showed marked Infected males scored notably higher for traits such as suspicion, jealousy and a disregard for rules, whereas infected females were found to be more outgoing, moralistic and warm-hearted. Studies have also found correlations between infection,

increasing parasite transmission

As we have seen, parasites are capable of adapting the behaviour of their host in sophisticated ways. host behaviour deliberate or are they some cases we certainly need to be

by parasites. For example, many worms can change the serotonin and dopamine concentrations in the brains of their hosts. Dopamine is also found in the parasitoid wasp venom, which sends cockroaches into that zombie-like state.

Testosterone and dopamine have

no longer display an innate aversion “R ats to the scent of their feline predator.” via contact between courting or mating! It actually appears that this behavioural change is an adaptation – a last-ditch attempt to generate death is imminent, as no energy or resources have to be saved for possible future reproduction.

So what is actually going on to cause these changes in behaviour? The

females were found to be more “Infected outgoing, moralistic and warm-hearted.” neuroticism and impaired motor performance. Although correlation does not equal causation, these are interesting observations.

Toxoplasma gondii

are only beginning to be uncovered.

A biochemical pathway in the host can be disrupted by chemical signals secreted by the parasite or may be accidentally disrupted by infection distinguish between these two possible mechanisms. However there have been recent advances in understanding what exactly is causing these behavioural changes. The brain chemistry of hosts is often altered

also been linked to the behavioural changes found in Toxoplasmainfected humans. Patients infected with Toxoplasma were found to have higher testosterone levels on average than uninfected patients. This may behavioural changes, as this hormone women. However this explanation is speculative at best.

As more is revealed about how exactly these miniature puppet-masters pull the strings, we gain a deeper understanding of the nature of behaviour. Indeed, the drastic impact that seemingly simple creatures may have on complex organisms begs the question of who is in control in such a scenario. Are we more puppets or puppet-masters when it comes to how we act? If a parasite infection can so profoundly change behaviour, we may not be as autonomous as we would like to think.

Isobel Routledge is a 2nd year Biological Sciences student at Wadham College.

Art by Hope Simpson and Iona Richards.

17

Bang! Talks to...

Prof. Sir Richard Peto Sir Richard Peto, FRS, is a Professor of Medical Statistics and Epidemiology at Oxford. He was knighted for his work in cancer prevention, and made a Fellow of the Royal Society for developing meta-analysis methods, which allow data from multiple trials to be considered together. He founded Oxford’s Clinical Trial Service Unit (CTSU), which conducts large randomised and observational trials, where his work on the causes of cancer, especially smoking, and of other chronic diseases such as stroke continues today.

You’re best known for your work on the dangers of smoking.

British men in 1970 had the worst death rate from tobacco of any population in the world. Britain had started smoking substantial numbers of cigarettes before any other country, epidemic. Since 1970, however, we’ve had the best decrease in the world in tobacco deaths – although it’s quite easy to have the best decrease if you Even in the 2010s, however, about 20% of all UK deaths before age 70 are still being caused by smoking, so it’s still the most important cause of death we’ve got. The good news is that it used to be much worse.

Although tobacco deaths are going down in this country, they’re going up in some other countries, the most important of which is China. Something like two thirds of the young men in China smoke. About half of those who smoke seriously from early adult life get killed by smoking, so something like a third of all the young men in China are eventually going to get killed by smoking, unless there’s widespread cessation. The prevalence of smoking among young women in China is

the 1950s, but throughout the 1950s and 1960s UK cigarette sales kept growing — they reached their maximum took some time for researchers to accept it, and it took a lot longer for people to understand this could be an avoidable cause.

You can avoid a lot more deaths by a moderate reduction in a big cause than

n the first decade of the 20th century, a “Ithey quarter of all the kids in Britain died before were 5. Now, only 0.5% do so.” less than 1%, so it’s very, very much a male habit. We’ve been monitoring the evolution of the epidemic in China for the past few decades, predicting how it will go over the next few to the government. The problem is that tobacco provides 10% of Chinese state revenue, and no government can lose 10% of its income. But, what the Chinese could do is what the French did. The French tripled the price of cigarettes since 1990, and consumption went down by half as a result, but the French government’s take from cigarettes went from 6 billion euros up Why keep studying smoking when the risks are so well-known?

The fact that smoking was a serious hazard was demonstrated in

18

you took all the other causes of cancer in this country that were reliably known and added them all together, smoking was causing more twice as many cancers as all the rest. And then it was killing more people by other diseases than by cancer. We’ve been saying this for decades, stressing just how big the risk from smoking is in comparison to other risks. Obviously if you’re in Russia, alcohol matters more than smoking, and if you’re in the Congo then war matters more than alcohol and smoking. Worldwide, there are 40 million deaths in middle and old age, and about 5 million of them are caused the smoking and it’s heading to 10 million.

What do you see happening in the future of death rates?

There might, of course, be something completely unforeseen that’s ten times

before age 100.) the 20th century, a quarter of all the kids in Britain died before they were 5.

Now, only 0.5% do so. Worldwide, a quarter of the kids born around 1950 died before the age of 5. Now, only 6% do so, and child mortality rates are still falling, so we can reasonably foresee a time when well under 6% of all kids die foresee a time when the main causes of death in middle age get reduced by half, if you deal seriously with the death, and have increased substantially in some big populations since 1990.

100

2010

80

percentage

however, my hope and my best guess is that child death rates will continue to decrease, that death rates in early adult life and middle age will continue to decrease, and that we’ll get closer to a world where it’s normal to survive until 70. (But, this wouldn’t make much

1960 1910

60 40 20

0

10

30

50

age

70

90

This graph show the percentage of men in England and Wales surviving to each age at the death rates in 1910, 1960 and 2010. companies, because there are other questions we ought to be addressing by randomised trials. I think also that high greatly increasing the price of patented drugs. In this country, we’ve now got legislation that makes clinical trials haphazardly and carelessly, and then it’s an incredible job to change them.

actually made less likely by smoking hundreds of times more deaths than it prevents. We got all of that through The really striking thing was that if women stopped smoking before age

better. We’re living a world where the underlying trend is for premature death to decrease.

Are any laws in the UK more helpful?

Misleading trial results have been giving pharmaceutical companies negative press recently. What do you feel should be done about this?

to determine really reliably what possible hazards cause what diseases.

If a trial is potentially informative and it has been done, then it should be reported. But we’re getting to the situation that there’s so many rules and

who were coming for breast screening

avoided more than 97% of the risk of getting killed by smoking. It could have been that if they had smoked for 10 years then it was too late for stopping to help, but that wasn’t what we found.

The women gave their permission for us to use their records, and it hasn’t hurt them in any way. Their names are all concealed while the data is being analysed, so nothing that could identify them ever gets published.

permission to access their medical records and see what diseases they

We need to protect the ability of medical research to use medical records

“T

Women study. Back in the 1990s,

here’s so many rules and regulations that nobody in their right mind would undertake a trial!”

regulations on people doing trials that nobody in their right mind would ever undertake a trial! We need to make it easier for people to run trials, so that we get lots of really good informative

Every few years she writes again and asks, what are you doing, what do you drink, what do you smoke?

over the last 20 years has been in the opposite direction. I don’t want circumstances where the only trials that can possibly be done are those patented drugs run by pharmaceutical

published in The Lancet on 27th

This has produced the world’s best evidence on the real hazards of smoking

Is some pill or other causing some out! Find out who used it, and then We ought to have that knowledge; it ought to be something that is routinely it has been, but new draft rules are now threatening to shut down such research.

This is wrong.

Interview by Sofia Hauck.

Art by Haneesh Sidhu.

19

The Patent Cliff

Pharmaceutical companies deal with loss of rights

O

ver the past two years, many of the world’s largest pharmaceutical companies have found themselves

direct competition with the original producers often leads to lower prices for both the original brand name

refers to the ending of patents held by pharma-giants over many ‘blockbuster’ drugs (drugs which

Against this background, pharmaceutical companies are becoming increasingly interested in an approach focused more on personal medicine, a model of treatment based on tailoring medicine to an individual based on their

A patent grants the inventor, or in this case the drug developer, rights to exclude others from selling their a time limit, and when this runs out, the drug developer loses those rights and consequently a lot of money, of the major companies to lose an In November 2012, the pharma-giant lost exclusive rights relating to the drug Lipitor, the biggest selling drug in history, with sales of over $125 billion

may be attractive to pharmaceutical companies, since if they could develop relatively small patient populations (rather than one ‘blockbuster drug’, which may be aimed at any patient with a particular symptom), then they may face a series of smaller Although we are a while away becoming the norm, the rapid research and advancements

Lipitor, the brand name for atorvastatin, is a synthetic compound used primarily to lower blood cholesterol in patients with a high risk

means that companies which

by inhibiting a major component of cholesterol production in the body, an

Another major shift occurring in the industry is the increased collaboration between pharmaceutical and biotech companies, as well patient groups,

towards this model, will be one step

patents run out, the developer “When loses those rights and a lot of money.” companies for whom patents have

in R&D and the production of new

for the drug Zyprexa, and AstraZeneca for Seroquel IR; both drugs used for

research partnerships between the company Vertex Pharmaceuticals

and leads to frequent lung can only be used to treat a certain kind of mutation found in its development is still a major

through many trials and changes over those companies with a willingness to adapt to the new climate and form themselves slowly climbing back to sustainable growth and generating

production and subsequent market in question — when a patent expires, other pharmaceutical companies are able to market and sell the same which no patent protection applies, and the sale of these drugs in

million to help produce Kalydeco, in a bid to combat the recessive genetic

Mahnoor Naeem is a 2nd year Chemistry student at Keble College.

Art by Iona Richards.

20

I love science but I don’t want to work in a lab for the next twenty years tackling technical concepts

I’d like a challenging career but I also want to enjoy life!

Does this sound familiar?

J A Kemp is a leading firm of patent and trade mark attorneys with offices in London, Oxford and Munich We are looking to recruit four patent attorney trainees in 2013 to join either our London office or our Oxford office.

Our work covers all areas of science and technology. www.jakemp.com

The Missing Folds Only a few of the possible proteins exist

Chemical catalysis, cellular transport and building complex structures are just some of the many functions of proteins. They are the workhorses of life. Each one is formed from a chain of several hundred amino acids; this constitutes the protein’s primary structure. This primary polypeptide structure gives rise to further arrangements, which eventually form a folded and tightly packed protein. The many possible functions of a protein are intimately connected with this progressive structural arrangement, and misfoldings can have tragic

thousand. Why has nature apparently restricted itself to such a limited selection of protein folds?

In fact, the abundance of possible sequences is part of the explanation.

Life has been evolving on Earth for around 4 billion years. Compared to the number of protein arrangements time to sample every possible potential proteins that have never been tried in nature, but is this the whole explanation for the lack of diversity?

Many scientists think not.

One possible explanation, albeit a rather boring one, is that the apparently “missing” folds are really a result of observation bias. Determining the structure of a protein is hard work: generally it’s done by X-ray crystallography. Before this can be done, the protein of interest needs to be crystallised. Some proteins crystallise more readily than others, and some don’t crystallise at all.

“T

proteins. serving as building blocks for the primary structure, there are around 10260 fairly typical protein 200 residues in length, compared to only 1080 atoms in the universe. Surprisingly then, when protein structures are determined, the same folds turn up over and over again, with most estimates putting the number of distinct folds at only a few

Secondary Protein Structure - interactions between amino acids form basic structures

Psychologists researching altruism often struggle to account for the complication of participant bias: the sort of person who volunteers

here are around 10260 possible configurations for a typical protein of 200 residues in length, compared to only 10 80 atoms in the universe.“

consequences. Diseases ranging from Alzheimers to sickle-cell anaemia have

Primary Protein Structure - a chain of amino acids

alpha helix

SE, or ‘mad cow disease’, led to the slaughter of millions of British cattle and billions of pounds in economic damage. The cause?

A misfolded protein, capable of inducing the same defective structure in others. Initial studies of protein folding were driven by curiosity rather than immediate application, but the medical relevance is clear. Despite huge advances in recent years, many fundamental questions in proteomics remain enigmas. This article explores one such puzzle — why we observe such a limited selection of structures in nature — and some of the more promising approaches to it.

pleated sheet

B

to take part in their experiments is unrepresentatively helpful and generous with their time. Could it be that biologists are experiencing the same problem, and that the apparently limited number of folds observed is a result of only being able to examine ‘helpful’ proteins which are easy to crystallise? Probably not.

In recent years protein scientists have improved structural determination methods and succeeded in solving previously intractable proteins; yet the distribution of folds has not been radically altered in the process.

22

Tertiary Protein Structure - distant parts of the amino acid chain react to form 3D shapes

Quaternary Protein Structure - two or more one amino acid chains bind together

Obviously it’s impossible to rule out a wealth of novel folds lurking in the most awkward, undetermined proteins, but there’s equally no reason to assume that they’re there.

If observation bias can’t explain the missing folds it could be that a simpler explanation is called for.

Are we certain the folds are there at all? It could be that many sequences simply wouldn’t resolve into working proteins. Several computational projects claim to have found novel folds which could have been used in nature; however, a theoretically stable fold may not be reliably reproduced in reality. Computer models don’t that some protein sequences can lead to ‘topological frustration’, where to fold before another, but energetic considerations cause another follow origami directions in the wrong order. This may therefore be at least part of the explanation for the limited number of observed folds, although the mechanisms of protein folding are

not yet well enough understood to

fall apart if the amino acid sequence changes slightly.

Perhaps, though, the decisive factor is not the capacity to attain a fold, but to continue to do so even when parts of the protein sequence have mutated?

It is well known in theoretical ecology that, in the presence of mutation, the

A similar argument suggests that it is instability, not stability which favours the common folds. We often picture proteins as rigid, machinelike structures, but they exist on a scale where statistical mechanics

be the most successful. As mutations

rule supreme. Protein structures

nergetic considerations cause another “Eorigami component to move first, like trying to follow directions in the wrong order.” increase in frequency, natural selection will favour an adequate but stable genotype (i.e. one where similar genotypes are also functional) over a cease to function if any part of it mutated. The latter is too unreliable.

Crossing the road without looking may save time, but not enough to make up for the risk! Similarly, it could be that the folds we observe are those which are resilient to mutation, while other folds may work in themselves but

frequently shift around their basic, ‘native’ state. These variant states ‘functional promiscuity’, and mutations will often alter the structure and properties of these variant states without impacting on the native state. Perhaps the common folds are favoured for the versatility of their variant states, and if other folds exist for the same core function they elsewhere.

It seems strange that so much mystery still surrounds such a well studied aspect of biology. No doubt more proteins could be made, but how many would fold successfully, and how many of those would be favoured by evolution? These questions may be answered before too long, as proteins and the mechanisms by which they fold become ever better understood, and basic science continues to be translated into novel drugs for diseases like Alzheimer’s.

For now they remain a matter for debate. Perhaps this is not such a bad thing. If nothing else, it’s gratifying for students and young scientists to be reminded that there are still big discoveries waiting to be made, even in the larger and better established areas of science!

Paul Richard Taylor is reading for a DPhil in Systems Biology at New College.

Art by Chloe Tuck.

Graphic by Iona Richards.

23

Socialising Ants

How do simple insects organise complex societies?

A

nts, tiny creatures synonymous with industriousness, live in societies that can number in the hundreds of thousands. The size and complexity of their societies means that they have evolved sophisticated methods of communicating with each other.

While bees communicate using dance, ants instead use pheromones — chemical signals — as the basis of their communication. These pheromones within the ant and each carries a

for the greater good of the colony.

There is no hierarchical structure; ants are equal and adapt to whatever stretching 4000 miles from Northern Italy to Spain is a super colony containing many billions of ants. This giant colony is formed of an invasive species from Argentina that can have many queens. The ants recognise other ants of the same extended enabling such a large colony to In other species there have evolved

to a food source, to alarms about

“T here is no hierarchical structure; even the queen potential predators, directions of where to dig in the nest, or a variety of social purposes such as caring for the young or the queen, and cleaning the nest. These chemical signals are detected by the ants’ incredibly sensitive antennae, which can detect a substance even if they only receive a couple of molecules. All insects can sense pheromones and use them to communicate in some manner, but receptors than most other insects.

Ants’ antennae are so sensitive that one gram of the trail pheromone is enough to lay a trail over six times the distance from the Earth to the Sun. From this simple method of communication very complex societies can arise. In these huge colonies, all

ants (Dorylus ) from central Africa to tropical Asia live in colonies of up to 700,000 members and have several

sections of leaves and bring them into their nests. These leaves are chewed into a paste and a fungus is cultivated on the leaf paste that the ants then ants (Lasius niger ) in the UK, farm aphids: the ants remove the aphids’ wings and place them on plants so the aphids can feed from the sugars within. The ants protect these aphids from predators and in return the aphids produce honeywater whenever the ants touch them in a certain location with their antennae.

These are just a few examples of the fascinating range of highly complex social structures and means of communication that ants have developed. Studying ants in their natural habitat is challenging but immensely rewarding, and learning about ants can help research in other disciplines, such as modelling for the behaviour of groups of robots. The intricacies of ants’ societies are vast, and we are still only just discovering

half a centimetre long, who tend to the eggs and larvae, to soldier ants, who are usually three times the size and guard the smaller ants from predators. These soldier ants also catch prey by sweeping through everything in their way in arcs up

to the pheromones released by together, these massive communities survive and prosper.

insects to provide food for the colony.

Leafcutter ants (Atta ) cut up large

24

Andrew Yeomans is a 4th year Physics student at Trinity College.

Rachel Blackford recently graduated in PPE from St. Catherine’s College.

Art by Aparna Ghosh.

Like Mother, Like Daughter Multiple genetic identities within one organism

T

he phenomenon of microchimerism means that part of me may have been left behind when I was born.

A chimera is a single organism composed of two or more genetically distinct cell populations. Nature contains many forms of chimerism, leading to a variety of biological phenomena. For example, the variegated ornamental plant varieties, valued by horticulturalists, are the

placenta. However, this exchange is not a one-way street, and cells from the foetus establish lineages within the mother that may persist for decades. After giving birth approximately 50-75% of women exhibit microchimerism. Maternal cells

tissues that require their partnership with normal photosynthetic green

The function of foetomaternal microchimerism in the human body is poorly understood. Microchimeric foetal cells are similar to stem cells

ceratioid group are also reliant on the

placental exchange and perhaps even through nursing, but they are less prevalent.

in fact a chimera, carrying “S hetwowas different sets of DNA.” merging of tissues, due to the rarity of encounters with the opposite sex. The male’s only endeavour in life is to latch onto a female and release an enzyme that allows their blood vessels to fuse together. The male then atrophies until all that is left is a pair of gonads that release sperm into the female.

Chimerism is not just restricted to ‘simple’ organisms. In 2002, Lydia Fairchild was ordered to have a judge present at the birth of her third child as DNA tests had implied that she was not the genetic mother of her previous two children, raising suspicion of her newborn third child also claimed that she was not the mother, it was discovered that she was in fact a of DNA. Large-scale chimerism in humans like this has been known since 1953, but is rare.

Microchimerism, however, is more common. Meaning ‘little mosaic’, microchimerism is the presence of a small number of cells in an organism that originate from another individual.

Placental mammals such as humans provision of a warm and safe internal environment for the their growing

in their ability to help repair tissues, and it may be that they confer way. Microchimeric cells have been observed to migrate to the injured heart of a mother rat, but there is currently no evidence as to their foetal cells are able to migrate to maternal melanomas, cancerous skin tumours. Foetal cells were found in 57% of B16 melanomas in pregnant mice, yet they are absent from normal skin. However, how this alters the prognosis is still unknown.

Microchimeric cells have even been found integrating themselves into the brain as nerve cells in rats. A 2012 paper found microchimeric cells in the brains of more than 60% of deceased women, and suggested that Alzheimer’s disease was less common in women with more microchimeric foetal cells present in their brain.

Unfortunately, your cellular necessarily all good. There is a positive correlation between microchimerism and prevalence of autoimmune diseases in women, although the mechanism is poorly understood. Among the cell types

25

transferred are foetal immune system progenitor cells such as immature T cells, also called CD4 cells. Capable of self-renewal, proliferation and the graft-versus-host type reactions seen in autoimmune diseases.

Surgical abortion procedures may even exacerbate this, with increased foetomaternal transfer of progenitor cells on the immune system might not be completely negative. Microchimeric cells have been suggested to ready the immune system for attacking tumours, and may even help in tumour prevention. may not quite live up to the image of a part-lion, part-goat and part-serpent beast from Greek mythology, it may make you closer to your mother than you realise, for better or for worse.

Tom Williams is a 3rd year Biological Sciences student at St. Anne’s College.

Art by Joy Aston.

Saving the Cute

When conservation efforts become popularity contests

C

onservation of biodiversity is fast becoming one of the most important issues facing our generation.

Current extinction rates are 100 to 1000 times greater than historical extinction rates, and are continuing to rise. In light of these worrying conservational and environmental problems have been established to try to stem the tide. The giant panda logo of the World Wide Fund for Nature (representing one of the most endangered species and a major focus of this protective movement. However,

endangered organisms remains “less-appealing” species is obvious in native to New Guinea. Echidnae are small mammals covered with spines, resembling a cross between an anteater and a hedgehog. With endangered species in the world. The three living species of these echidnae are highly prized game species and are regularly hunted by locals with trained dogs. Large tracts of land are being exploited for farming, logging

of these iconic species are “Most large with forward facing eyes.” the use of this adorable mascot may conceal one of the great problems with our current model of ecological conservation.

and mining, further reducing and contaminating any available habitat.

The echidnae have thus become highly threatened species. Despite being

Traditionally, the most successful approach to raise support for conservation has been to champion species based on their popularity and visual appeal. The public typically prefers to support endangered species associated with conventional aesthetic values. According to Dr. Robert Smith of the Durrell Institute of Conservation and Ecology, most of these iconic species are large with forward facing eyes, as people

by the International Union for Conservation of Nature, the species have received very little attention from

impressive and can easily identify with faces resembling those of humans. Charismatic iconic species, such as the polar bear and the Sumatran orangutan, receive the most attention and funding. One conservation strategy for the giant panda suggests that this species alone merits tightening of forestry laws and provincial regulations, as well as 2 of protected area.

This model for ecological conservation species receive little or no funding, and public awareness for some critically

means that there are currently no targeted conservation measures in place, especially for Attenborough’s Zaglossus attenboroughi endangered.

For species that conservation further challenges. foxes are particularly unpopular local wildlife in rural New South Wales and Queensland, as they endanger local food supplies through their occasional habit of feeding on the fruit crops. Flying foxes can also transmit the Hendra virus

26

to horses, threatening local farms.

Increased regional temperatures and selective culls caused the national fall by 30% in the 1990s and it is continuing to decline today. Despite a crucial role in local ecology, as they are responsible for pollination and seed dispersal. Their intelligence and complex social interactions are and the media, who have called these

100,000

unique mammals “disease-ridden pests” and “killer bats”.

Distant Past (fossil record)

Recent Past (known extinctions)

Future (modelled)

10,000

1,000

100

Staphylococcus aureus (MRSA) and multi-drug-resistant tuberculosis

10

1

can be done to protect “What these less appealing species?”

0.1

Marine Mammals

reactions on which multicellular organisms depend, such

Mammals Birds Amphibian

All species

Extinctions per thousand species per millenium, according to the Millenium Ecosystem Assessment.

conservation initiatives. Raised public awareness has to be stakeholders, so that conservation can also be carried out aquatic species.

What can be done to protect these less appealing species?

aesthetic species should complement current conservation

75

70

communities. Programmes should be built around these

10

5

Plants

Insects

Fishes

Reptiles

Birds

Mammals

Species profiled in the WWF website (wwf.org) per group.

Terence Tsz Long Tang is a 1st year Biochemistry student at Somerville College.

Art by Jade Barrett. Graphics by Sofia Hauck.

27

Bang! Crossword 1

2

3

4 5

5. The study of poisons 6. Stage of sleep where dreams are most vividly recorded 9. An important Main Belt asteroid 11. Method of encoding information or messages 12. The home of a parasite 13. The building blocks of proteins: acids

Down

6

1. State of an organism with two sets of genes 2. A chemical that triggers a social response 3. Prevents you from eating rotten fruit 4. Neurotransmitter involved in the brain’s pleasure and reward centres 7. Model for particles and forces that constitutes best theory of physics 8. Having both male and female reproductive organs 10. A community of living organisms

7 8

Across

9

10

11

12

13

Find the answers throughout the magazine!

28

Art by Jade Barrett.

http:/ www.bartlet .ucl.ac.uk/energy http:/ lolo.ac.uk

http://www.bartlett.ucl.ac.uk/energy http://lolo.ac.uk

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