SYNAPSE THE SCIENCE MAGAZINE WRITTEN BY STUDENTS FOR STUDENTS
ISSUE 6 - November 2013 - FREE
A DAY IN A MARS MISSION
Despite all our artificial lighting and strong coffee, even us humans remain dependent on regular sleep-wake cycles
How Many People Can The Earth Support? Evolution: When Suicide Makes Sense
EDITORIAL
The Synapse Team Felicity Russell Editor In Chief
Louisa Cockbill Senior Editor and Vice President
Tom Stubbs
Secretary and Media Director
A Message from the Editor In Chief Welcome to the sixth issue of Synapse Science Magazine, the University of Bristol’s student science magazine. In this issue we discuss the potential of glowing eel proteins, the challenge of a Mars mission and the crisis of antibiotic resistance. We are a magazine written by students for students and if you would like to get involved as a writer, editor, photographer or graphic designer please let us know by contacting us at: synapse.scimag@gmail.com
Oliver Ford
Senior Editor and Treasurer
Daniel Ward
Senior Editor and Graphic Designer
Article Editors Molly Hawes Managing Editor
Ione Bingley Alfred Omachar Hannah Bruce Macdonald
Katherine MacInnes
Senior Editor and Publicity Officer
Natalie Parker Cher Bachar Naomi Farren
Toby Benham Senior Editor
Rachel Greenwood Georgina Winney Erik Müürsepp Georgina Maguire
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CONTENTS
Articles
On the cover
4. Left Handedness 6. How Many People Can The
12. A Day In A Mars Mission 6. How Many People Can The Earth Support? 18. Evolution: When Suicide Makes Sense
6.
Features
Earth Support? 8. The Death Of Moore’s Law and the Birth of Quantum Computing 10. Back From The Dead 11. Fluorescent Eel Protein Gets A Glowing Review 14. A Bright Idea 16. The Lure of the Lottery: A Tax on the Dim? 20. The Antibiotic Crisis
Marvels
23. Pharmacogenomics
12. A Day In A Mars Mission
18. Evolution: When Suicide Makes Sense
Join us online!
www.synapsebristol.co.uk @synapsebristol
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ARTICLES The majority of the population (around 90%) prefer to use their right hand, with the remaining 10% either favouring their left or having no preference. So what makes this 10% different? And are there advantages or disadvantages to being a lefty?
Left Handedness Rachel Cole
Hand Vs Hemisphere Dominance
The two hemispheres of the brain are often associated with different functions. For the majority of people the language centres are located within the left cortex, their brains are described as being ‘left dominant’. There is, however, a minority who have language localised to the right side and their brains are considered ‘right dominant’. Almost all right-handers are left hemisphere dominant due to the brain predominantly controlling the contralateral side of the body, but strangely only 35% of left-handed people are right brain dominant.
What Determines Hand Preference?
There is evidence to suggest left-handedness can be both a genetic trait, termed “natural left-handedness”, or can result from brain damage known as “pathological left-handedness”.
G
enetic Influence Left-handedness is more common in offspring from left-handed parents than righthanded parents suggesting that hand preference can be passed from parent to child either via genes or via the learning environment. Interestingly, left-handed mothers are more likely to have left-handed offspring than left-handed fathers this implys that, either the maternal influence is stronger, or that the gene for handedness is X chromosome linked. At least some heritability for handedness is predicted because it is more likely for both identical twins to be left-handed than non-identical twins.
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H
and Preference Determined in utero The foetus begins to show arm preference as early as 9 weeks into gestation; moving one arm considerably more than the other. Testosterone levels to which the developing foetus is exposed are thought to impact on handedness. High testosterone levels, which can result from genetic influences, are thought to slow development of the left hemisphere selectively. Elevated prenatal testosterone has also been linked to dyslexia and impaired thymus growth. This provides a possible explanation for why left-handedness is more common in those suffering from immune or neurological disorders.
Negative Associations With Left-Handedness
Reduced Lifespan
Multiple studies have shown people who are left-handed have reduced longevity relative to the right-handed population. Possible reasons for this include: • A greater likelihood of problems having occurred in the womb or during birth. • A compromised immune system due to impaired thymus growth, as previously mentioned. • An increased risk of experiencing fatal accidents due to equipment being designed for right-handed use.
Neurological Disorders
Left-handedness and ambidexterity are more prevalent in those with neurological disorders including autism, schizophrenia, epilepsy and Down’s syndrome. The higher prevalence of left-handedness in epileptics is explained by some patients experiencing seizures localised to the left hemisphere, particularly affecting the language areas. Due to the plasticity of the brain, language functions can be re-distributed to undamaged regions in the right hemisphere, altering brain dominance without impairing the ability to communicate. Over 50% of autistic children have been found to be left-handed or ambidextrous, considerably greater than the expected 10%. If brain damage in Autism was purely localised to the left hemisphere, language and other functions would be taken over by the equivalent regions on the right side enabling normal function. However, autistic individuals have multiple difficulties with the interpretation and production of language. It is thought that brain damage occurring in utero or early life in autistic infants may affect the language centres in both cerebral hemispheres, impairing the ability of the cerebral cortex to lateralize functions in the normal manner.
Positive Associations With Left-Handedness
Larger Corpus Callosum
Studies have found non-right-handers to have a larger corpus callosum (the major band of white matter connecting the two hemispheres of the brain) and, consequently, there is more efficient transfer of information between the two sides of the brain thought to be required for some types of memory.
Creativity
Left-handed people are often thought of as being more creative, possibly due to the large number of famous left-handed musicians and painters, including Sir Paul McCartney and Leonardo da Vinci. Although considered a myth, some studies support this statement and claim the difference exists because the world is designed for right-handed people forcing left-handers to be more creative to overcome environmental challenges.
Sports
Being in the minority, left-handed athletes often have the advantage in 1 on 1 sports such as tennis as players will have had more experience facing right-handed opponents. Although research supports all of these associations with hand preference, there are multiple studies contradicting these points, so conclusions remain ambiguous. However, there appears to be more health risks associated with left-handedness. Whether these risks are associated with the entire left-handed population or just those who acquire left-handedness pathologically remains unknown.
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ARTICLES
N
umerous statistics have been thrown about regarding future human population growth, with the milestone of 7 billion having been reached relatively recently. With the one billion mark reached only a meagre 200 years ago, it could be argued that this alarmingly fast rate of growth will soon reach a summit of uncontrollable measures. Even pre 18th century, philosopher Thomas Malthus argued that human’s unquenchable urge to reproduce would ultimately lead us to overpopulate the planet, eat up all its resources and die in a mass famine. However, with predicted figures ranging from billions to tens of billions and beyond, it is difficult to say what the world population will be by 2100 for example. There is also a question over how such an incredibly vast number of people can be accurately counted. It is possible that rapid population growth is just a natural phenomenon and that there is not much we can do in response. However this would not seem to be the case. The number of people that can populate the planet depends on the way that people live. With present levels of food production and an equal distribution of food, it has been estimated at Brown University that “the world could sustain either 5.5 billion vegetarians,
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How Many People Can The Earth Support? 3.7 billion people who get 15 per cent of their calories from animal products (as in much of South America), or 2.8 billion people who derive 25 per cent of their calories from animal products (as in the wealthiest countries)”. This indicates that we do have some control over how many people the Earth can support. Eating vegetables rather than meat cuts out a trophic level in the food chain meaning that less land space is consumed per person. In fact, a separate study has estimated that if everyone lived as Ghanaians, then the world could support 16 billion. There are several different perspectives to consider when determining a figure. Ecologically speaking, there is only a certain amount of land space worldwide to grow crops for food and food could be a key limiting factor
Toby Benham
on further population growth. More people means more land used up for housing instead of crops; it’s a vicious cycle. The amount of nitrogen and phosphorus (used for crop growth) is also finite. Problems could be eased by GM crops, but this brings about a new problem – there are ethical issues with GM crops which have to be dealt with politically. Political decisions like this are crucial in setting the limit on the number of inhabitants on Earth. Politicians will have to deal with the consequences otherwise, such as increasing demands on healthcare services, schools, prisons etc. Economically speaking, mass unemployment could result in too many people and too few jobs. Furthermore, as healthcare improves, the economy may be crippled by its attempts to support the increasingly
elderly population. Large food distributors will have an important effect, depending on how responsible they decide to be. For example, rather than throwing away unsold food it would be much more sustainable to give it away to those in need. However this would not be good for business. Would companies be prepared to do this on a large scale? There are also those who argue that improving technology will be able to cater for more people. The Sun radiates enough energy down to Earth to easily meet current and future energy demands. If this energy could be harvested effectively,
the fuel crisis would be solved. This would require funding though; something which may not be readily available. Hopefully it has become evident that there are many factors which will affect the number of people that could sustainably live on Earth. There is a finite amount of resources available to us, but through technology and political decisions, we could use our current resources more efficiently. Fortunately, UN estimates of global population trends show that families are getting smaller and “empirical data from 230 countries since 1950 shows that the great ma-
jority have fertility declines”. Globally, the fertility rate is falling to the ‘replacement level’— 2.1 children per woman, the rate at which children replace their parents (and make up for those who die young). With population growth nolonger booming, increasing worldwide sustainability awareness and the efficient use of resources, the human population will likely stabilise to a figure not far from 10 billion. The Earth’s sustainability is being pushed to its limit, but there is no reason why we can’t reach a stable population within a hundred years or so.
There is a finite amount of resources available to us, but through technology and political decisions, we could use our current resources more efficiently.
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ARTICLES
The Death of Moore’s Law and the Birth of Quantum Computing Matthew Cole
I
t was recently announced that Google had bought the D-Wave Two, a commercial quantum computer, to use in collaboration with NASA and the Universities Space Research Association. D-Wave, the company that produces the computer, claims it is 3600 times faster at performing certain tasks than conventional computers. As Moore’s Law slows down and eventually becomes obsolete many are looking to quantum computers to develop our technological ability. Moore’s Law is predicted to become defunct in around a decade or so by prominent physicists such as Michio Kaku. In Kaku’s own words ‘…in about ten years or so, we will see the collapse of Moore’s Law. In fact, already we see a slowing down of Moore’s Law. Computer power simply cannot maintain its rapid exponential rise using standard silicon technology.
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The collapse of Moore’s Law, which originally predicted transistor density doubling every 18 months and has since come to represent the general rapid improvements in computing size, speed, density and cost. Towards the end of this year the pace of transistor density doubling is itself expected to double to around three years. Nevertheless, the slowing of Moore’s and other technological laws is to be expected. After all, there will come a point when transistor size is constrained by the size of atoms themselves. There are not only physical reasons for the cessation of Moore’s Law but also commercial. A time will arrive, if it’s not already upon us, where it is increasingly uneconomic for chip manufacturers to invest in the technology to sustain Moore’s Law. It is computers which will utilise quantum effects that many people are looking towards to
provide the next great leap in computing power. Traditional computers use classical bits: a transistor either has a value of 1 or 0 (on or off essentially); whereas quantum computers use quantum bits, known as qubits, instead. Qubits have the advantage of being both on and off at the same time, the implication being that quantum computers can do calculations simultaneously. The key, and frankly bizarre, quantum properties that allow quantum computers to do this are entanglement and superposition. When quantum states are entangled they are linked, so when something happens to one state it will cause an almost instantaneous effect in the other state even if the states are spatially separated. It is quantum superposition that asserts that a physical system exists partly in all of its theoretical states simultaneously, but when the system is measured it will then take a definite configuration. There are scientists trying to create ‘universal’ quantum computers from physical qubit systems, which are able to perform every conceivable calculation like a traditional computer. However, this type of quantum computer is extremely susceptible to interference and dissipation, hence why a commercially viable one hasn’t been built yet. There are difficulties concerning errors in these types of quantum computers and it is predicted several multiples of the productive qubits will be needed simply for error correction. The D-Wave devices have managed to bypass most of the problems associated with universal quantum computers by harnessing a phenomenon known as adiabatic quantum computing to carry out calculations. This type of quantum computer is best suited to optimization problems where the best answer from the available options must be calculated simultaneously. In such a computer the qubits are meant to stay in their lowest energy state at all times which means it is much more stable than a universal quantum computer. However, this results in the computer having limited functionality, for example, it struggles in calculations
where extremely large numbers are factorised. There is a healthy dose of scepticism surrounding the D-Wave quantum computers. It was only recently that the significant cloud of doubt, over whether the machine even demonstrated quantum effects at all, was lifted. Google’s recent purchase of the D-Wave Two was accompanied with the much hyped statistic that the D-Wave Two could perform certain tasks 3600 times faster than a high end desktop computer. Although this is an impressive statistic the fact is the DWave Two costs $10 million dollars, enough to buy several thousand high end desktop PCs. Furthermore, as Scott Aaronson of MIT points out, the PC algorithms hadn’t been optimised to solve the experiment unlike the D-Wave machine. This lopsided competition further obscures a true comparison between the D-Wave machine and classical computing processes. Nevertheless, despite criticisms of the D-Wave devices it must be remembered that these are the world’s first viable quantum computers. This is a significant step in the development of quantum computing devices.
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ARTICLES
Back From The Dead
Sarah Jose
I
Lazarus taxa are rare but inspirational accounts of species coming back from the brink of extinction.
magine turning the corner in a dense forest and coming face to face with a dinosaur. In 1994, David Noble abseiled into a canyon in Australia and discovered the botanical equivalent; the Wollemi pine, a living descendant of a 200 million year old family thought to have died out 2 million years ago. This is an example of a Lazarus taxon; believed to be extinct but later rediscovered alive. The name ‘Lazarus’ comes from a Bible verse where Jesus brings Lazarus back to life four days after his burial, whilst a taxon is a unit used to group one or more related species. Lazarus species are a source of hope for conservationists, giving us another chance to save species like the mahogany glider, a beautiful possum lost to science for over 100 years. Much of its forest home is now protected by Australian National Parks. Similarly, the Bermuda petrel was believed extinct for 330 years, but 18 breeding pairs were found in 1951 and an intensive conservation effort has allowed the population to creep up to 250 birds. Other living fossils like the coelacanth provide a fascinating insight into evolution. Thought to have gone extinct alongside the dinosaurs, this fish has limb-like fins and is more closely related to mammals than most other fish. It could hold a clue to how vertebrates migrated from the sea to the land over 375 million years ago. Lazarus taxa are rare but inspirational accounts of species coming back from the brink of extinction. We need to make the most of these second chances and use these umbrella species to invigorate conservation efforts and protect entire ecosystems.
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Fluorescent Eel Protein Gets a Glowing Review A
fluorescent protein found in several freshwater species of eel holds exciting potential for the medical industry, scientists from the RIKEN institute in Japan have found. Named UnaG (from unagi, the Japanese word for the eels, and G for green), the protein glows when combined with the yellowish pigment bilirubin - normally produced when the haemoglobin in red blood cells breaks down. Researchers are currently hoping the unique macromolecule may be used to diagnose medical conditions such as jaundice. Although the exact natural function of UnaG is uncertain,
Tim Smith
it is thought to play a role in muscle physiology during eel growth, scientists are testing its possible applications as an indicator in the human body. The healthy human is quite capable of disposing of the natural production quota of bilirubin pigment. In the case of individuals whose bilirubin-busting machinery has malfunctioned however, as well as those born with defects, high levels of bilirubin can accumulate over time, causing jaundice, brain damage, or even death. It is now expected that the newly discovered relationship between UnaG and bilirubin could be used to the patient’s advantage. By measuring the intensity of protein fluorescence, doctors may be able to extrapolate the levels of bilirubin in the body and potentially save lives. Still not convinced of UnaG’s potential? Well, researchers believe that this little protein may also prove useful as an indicator for other molecules, and even whole cells, in many other important procedures.
Unlike most other compounds, UnaG is able to fluoresce in low- to no-oxygen environments, meaning it may be useful in the study of tumours. As well as a medical breakthrough, the discovery of UnaG and its properties also demonstrates the life-saving importance of the natural world around us. As if the inherent value of nature wasn’t enough, the probability of further undiscovered cures or medical ‘tools’ should encourage everyone to be more protective of our fragile environment and the unique potential it holds; our survival may depend on it!
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FEATURE
A DAY IN A MARS MISSION Jonathan Smith
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T
he majority of life on Earth exists in 24-hour cycles, based on the time taken for Earth to rotate in its orbit. Despite all our artificial lighting and strong coffee, even us humans remain dependent on regular sleep-wake cycles, the disruption of which can have bad effects on our health. This could be a headache for future manned Mars missions since the long journey to Mars will be in an isolated environment where it’s hard to maintain daily rhythms. Why are these problems important and how can we tackle them? Firstly, we need to know how the body encodes a ‘day’. Most terrestrial organisms have evolved a timekeeping system of physiological fluctuations called ‘circadian rhythms’ (circa = near; dia = day). These rhythms are based on roughly 24-hour-long feedback loops of gene expression which are used to optimise essential body functions throughout each day, such as sleep and hormonal regulation. Interestingly, even though these rhythms are genetic in origin, they are also ‘tuned’ to Earth’s rotational periods by means of cues from the environment such as visible light and food intake, meaning that we influence our rhythms by light exposure and our own behaviour. Very importantly too, our sleep-wake patterns both influence, and are affected by, these circadian rhythms. Anyone suffering from jet lag knows the effect of sleep/wake cycle disruption on our function. Thankfully, jet-lag usually clears within a week once we acclimatise to the new day-night cycle. What if, however, we were in a spacecraft going to Mars and back, with few
cues for our circadian rhythms? A recent study carried out by the European Space Agency has provided us with some insight into the behavioural and psychological consequences of a mockup mission, called the Mars 520-d mission simulation, carried out in Moscow. The results revealed some interesting trends. Firstly, only two of the six crew were relatively free of psychological problems by the end of 520 days in isolation. Very noticeably, the crew increased their average time spent asleep by the end of the mission. Not only that, but productivity and alertness were also suffering, potentially jeopardising a real mission. The conclusion of this simulation was that the circadian rhythms of the crew were de-synchronising and this coincided with detrimental effects on their ability to complete tasks effectively. Clearly, there’s a need for ways in which we can better train astronauts to maintain a regular circadian cycle in missions. In fact, solutions could be fast approaching. Other studies have suggested ways of maintaining stable circadian rhythms such as regular exercise regimes, short wavelength light exposure and diet control. There are even studies indicating that it’s possible to entrain ourselves to a martian ‘day’ of 24.67 hours rather than terrestrial 24-hour days - quite a large difference considering the amount of time we might spend on Mars itself. Finding a way to integrate these techniques into a zero-gravity Mars mission set-up may be a good, but challenging, solution. At least all we would need to worry about after that is any lethal radiation in space!
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ARTICLES
A Bright Idea
Cormac Kinsella
S
ometimes in science it is difficult to see how subjects can relate to each other. Computer science and biology may seem superficially distinct, yet ask any ecologist and they will tell you the importance of programming languages and modelling. The ecological models devised will in turn be used by those studying fields from macroevolution to conservation biology. Despite this, and understandably, scientists are often highly loyal to their own niche, perhaps
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to the extent of dismissing others as uninteresting and irrelevant. Didn’t our parents and teachers always remind us sharing was good? Well it seems this lesson holds true for science also. The removal of our blinkers can allow amazing things to happen, giving birth to novel amalgamations of established science. One such example which has the potential to revolutionise behavioural neuroscience (and others) is optogenetics. In essence, optogenetics is
the bioengineering of neurons, enabling the researcher to control the firing of action potentials (activating or inhibiting them) using light. It is optical mind control. In order to do this, light sensitive proteins that respond by causing or inhibiting responses (actuators), and another type which report activity (sensors) must be expressed in the cells. The DNA encoding these tools has been collected from many organisms, from jellyfish to halobacteria. Optogenetics combines several fields of science, ranging from optics and microendoscopy through to bioengineering and genetics. Unlike other methods for studying the mind which stimulate brain regions e.g. deep brain stimulation, optogenetics has uniquely accurate cell specificity, down to individual neurons. The implications of this are huge, as it allows us to study the workings of the mind at the scale of its building blocks. The cells responsible for a host of responses and instincts can be teased out of hiding, and consciousness can be stripped down to its physical workings. Importantly, it is carried out in
living animals, allowing the behavioural or physiological effects of neuron stimulation to be observed in real time. For example, a study published in 2008 using a type of light sensitive protein called channelrhodopsin-2 expressed by the neurons of zebrafish larvae showed that a single action potential in a single neuron was enough to cause escape behaviour. The applications of such a method are potentially massive – already it is being used in neuroscience studies, spanning from olfaction in flies to sleep studies in mammals. It has implications for the medical field from drug addiction and neuropsychiatric disorders to Parkinson’s disease. In the latter example, researchers have already managed to both induce and relieve
symptoms of the disease, working on the basal ganglia of mice. There is even an application for non-neural cells: researchers believe that light driven pacemakers are not beyond the realms of possibility. Relatively speaking, it is a brand new research area, yet has developed rapidly. Suggested as theoretically possible in 1999 by one Francis Crick (Nobel Prize winner and co-discoverer of the structure of DNA), it was first put into practice in 2002. The term ‘optogenetics’ was first used in a 2006 publication, and has since been adopted by researchers around the globe. In 2010 the journal ‘nature methods’ named optogenetics ‘method of the year’, and the same year saw one of the pioneers in the field, Karl Deisseroth, receive
a prize ($10,000) for his work. Compare that fund with the €250,000 awarded in 2012 to the founder of optogenetics, Gero Miesenboeck. Who knows, perhaps the next few years will see a Nobel Prize go to optogenetics researchers. To conclude, I believe we should see optogenetics as a lesson to us all, to remember to view our own work in the light of the bigger picture. Optogenetics took a large change in mind-set from traditional neuroscience, from observing to controlling neurons using breakthroughs in other fields of research, in order to crack the code. The next big thing could be right under our noses, but requires us to be open to trading between branches of science. After all, are we not studying the same tree?
Neural cells activated by light delivered by optic fibres through the rat’s skull.
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ARTICLES
The Lure of the Lottery:
‘A Tax on the Dim’? H
ave you ever felt the excitement as you pick your lucky numbers? The buzz as the draw is announced? Found yourself lost in fantasy at the prospect of a jackpot win? If you are a lottery player, the answer is probably yes. But have you ever questioned the rationality behind your decision to play? Financially speaking, playing the lottery is simply an irrational decision, since the price of a ticket weighed
Eira Fomicheva
up against the phenomenally low probability of winning means purchasing a ticket offers a negative expected return. So, as the most intellectually advanced species on the planet, why is the lottery such an inherent part of our culture? Is the lottery simply a so-called ‘tax on the dim’, or is there a rational explanation for what is a financially irrational behaviour? The data show us that the lottery is a regressive
Financially speaking, playing the lottery is simply an irrational decision
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tax – those with lower incomes spend a higher proportion of their money on playing the lottery, becoming yet poorer, and so the cycle continues. A 2008 study showed that households with an income below $13,000 a year spent a startling 9% of this on the lottery. Accordingly, it has been theorised that lesser-educated individuals choose an option with a negative expected monetary return simply because they do not identify it as such. So, do lottery players simply misunderstand the odds they face? Our complex cognitive architecture is hardwired to over-perceive patterns and connections between random events, and many cognitive biases from gambling literature have been applied to playing the lottery. For example, research shows that unsuccessful lottery players tend to erroneously believe that a self-correcting process will make them more likely to win subsequent draws, and that winning numbers are less likely to be drawn on subsequent weeks – the ‘Gambler’s
Fallacy’. The lottery in particular lends itself to these cognitive biases, since it involves no element of skill, and the odds lie far outside the usual range of probabilities we encounter when decision making. However, while lotteries do offer a negative expected financial return, it is not necessarily the case that a distorted perception of probability drives people to play the lottery– it is important to consider the crucial role of emotions. In 1995, a man committed suicide following the realisation that his usual numbers had won that week’s lottery. In the same year, psychiatrists coined the term ‘Lottery Stress Disorder’, when several patients presented with grandiose thoughts and distorted optimism on the run up to each weekly draw, followed by a sudden depression. Accordingly, researchers have suggested that lottery playing might be driven by the avoidance of regret, a phenomenon exploited by lottery marketing teams who use slogans such as ‘it could have been you’. Postcode lotteries are a particularly potent source of anticipated regret. A postcode is picked at random to win a large jackpot – if the resident does not hold a ticket, they lose out, and are informed of what they would
have won. One study found that these lotteries evoked significantly more anticipated regret than standard lotteries, which then directly affected informed of what they would have won. One study found that these lotteries evoked significantly more anticipated regret than standard lotteries, which then directly affected the decision to participate. Clearly regret is not a pleasant emotion to experience, therefore to avoid it for a small cost arguably is a rational choice. Playing the lottery is not only driven by negative emotions. If you’ve ever bought a lottery ticket, you’ll be familiar with the daydreaming it facilitates, and the buzz that follows. Theorists have suggested that the lottery acts as a socially acceptable outlet through which to relieve tension and maintain hope – ‘strain theory’. The lottery offers life-changing jackpots, and allows us to indulge in daydreams about the unobtainable: therein lies its lure. Playing the lottery might be a highly functional strategy for relieving the stresses of life, which can offer an explanation for the correlation with poverty. Strain-relief might be particularly seductive for those of a lower socioeconomic status, with more frustrations to channel.
Before dismissing lottery gamblers as ‘dim’ and ignorant to probability, we must consider that social and emotional factors can provide rational explanations for what is financially an irrational decision. Rather than being a ‘tax’ on those not educated enough to fully grasp the odds, the use of playing the lottery might lie in its strain relieving nature – this offsets the negative monetary return. The benefit of making the choice to play the lottery is not the same as its monetary value, and the non-monetary value of lottery play is subjective, unquantifiable, and not to be underestimated. A lottery ticket is a small price to pay for a license to momentarily escape reality. At the same time, it’s important to remember there might be negative consequences of this strain-relieving strategy in the long run. Lottery gamblers should be aware that they are purchasing a licence to daydream, alleviate strain, and avoid regret – all in exchange for a small cost. The unlikely event of winning the lottery would be the icing on the cake, but problems such as pathological gambling and debt arise when lottery gamblers do not feel satisfied until they have won against the – almost impossible – odds.
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Evolution: When Suicide Makes Sense
FEATURE
Mark N Puttick
“Would you give your life to save a drowning brother?” “No, but I would to save two brothers, or eight cousins”
B
iologist JBS Haldane’s laconic response to this question points towards a scenario in which self-sacrifice, and even suicide, can occur in nature. On the face of it, in nature killing yourself makes no sense, and almost everything that happens in nature suggests it shouldn’t happen. Zebras don’t jump into Lions’ mouths, birds don’t deliberately fly into wind turbines, and lemmings definitely don’t throw themselves off cliffs (this apparent suicide is due to high mortality during migrations). All of a creature’s energy goes into two things: surviving, and having sex (or reproducing in some way). Yet, suicide can make evolutionary sense, and as suggested by Haldane’s quote, it is all about family. More specifically, it is about whom carries the same genes as you do. On average you share half your genes with your parents, and your brothers
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and sisters, but you share all of your genes with yourself. The more distantly related you are, the smaller the percentage. So it’s not worth killing yourself to save one sibling as you are losing half of your genes (all of your genes, and only half the equivalent in your sibling), but by saving two siblings you are effectively saving another version of yourself. However, you would never die for a stranger, and never for the ‘good of the species’, which is a common misconception; strangers simply aren’t related to you enough. In biology this concept of altruism is known as kin selection, and the concept of helping relatives is known as Hamilton’s rule, named after another biologist, WD Hamilton. Many of these ideas inform the gene-centred view of evolution, championed strongly by Richard Dawkins. So helping others can occur in nature, but how common
is the ultimate sacrifice of giving your life for others? At the cellular level it is vital. During development, cell death (technically called apoptosis) is essential; without cell death you would be born with webbed hands and feet (and some people are), and it is likely the lack of cell death played a role in the condition suffered by the ‘elephant man’ Joseph Merrick. Another bizarre example of sacrifice is seen in the sperm of the European wood mouse. When a female wood mouse mates with more than one male, a form of ‘sperm competition’ ensues as only one sperm from a mixture of male sperm can fertilise the egg. Some related sperm (sperm from one male share half their genes) group and form a ‘train’ that moves at twice the speed of an individual unrelated sperm cells; these trains reach the
egg first, but to leave the train most sperm have to undergo the same reaction that would allow them to break through the egg wall. One sperm that did not do this reaction can fertilise the egg. The sperm cells in the train acted altruistically by carrying their brother, but by sacrificing themselves and their chances of life. But we are primarily interested in suicide at the whole organism level, and some cases are known. Dying individuals in a European ant species and honeybees will remove themselves from the colony to die alone. By dying alone away from the colony the dying ant ensures its relatives are less likely to become infected by whatever killed it. Research in bacteria has shown that relatedness may even be unimportant, as the ‘cost’ of suicide is so low, microbes can afford to kill themselves. A natural thought is if this applies to other animals and humans. As yet, most
research has focused upon microbes and social insects (such as bees and ants), and questions remain. A myriad of other explanations could be put forward for the apparent suicide. One is ‘Zombie ants’, which sounds like a 1950s B movie, but is also a phenomenon that could be used as one argument against apparent suicides. Certain Camponotus ants exhibit strange behaviour; they will leave their colony, climb a plant, bite on a leaf, and then they die. However, this is not for suicidal reasons; these ants’ brains are infected by a fungal pathogen that controls their movements, kills them, and grows off their remains. The reason they go to the top of a plant is to most effectively spread pores of the fungus. So could reasons like this explain these observed suicides in ants and bees? Well, research has to show that suicide has an adaptive effect, and that those groups with the ability to commit
suicide are better survivors than those that do not. Recent research has shown just that: acts that look like suicide, are suicide if they are beneficial to a group, and these can be distinguished from nonbeneficial cases, such as the ‘zombie ants’. All in all, the most recent research suggests suicide is most likely to occur when the costs are low. That is to say, when you’re going to die anyway, make it better for your relatives by committing suicide (these words do not reflect my social views). Just as Captain Oates ‘went out for some time’ on the doomed Antarctic mission, microbes and social insects on the verge of death will die so others may live. Much anecdotal evidence suggests animals and people will commit suicide for others, but no firm evidence has been provided. Yet, sometimes in the natural world, under specific circumstances, suicide makes sense.
Dying individuals in a European ant species and honeybees will remove themselves from the colony to die alone.
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ARTICLES
THE ANTIBIOTIC CRISIS
Sophia Ho
There has been much attention in the popular press recently concerning the worrying lack of new antibiotic development along with the continual, worldwide rise of antibiotic resistance to existing drugs. Indeed, why do such problems continue to be the case? Why is nothing being done by the pharmaceutical industry to resolve such a crisis? Will this eventually lead to us running out of options to treat bacterial infections?
A
ntibiotics (sometimes known more generally as antimicrobials) are natural molecules produced by micro-organisms, such as bacteria and fungi, but their exact function is unclear. Originally, it was believed that antibiotics were secreted in order to inhibit the growth of other organisms that may compete for food and space. However, as they usually produced in very low levels, it appears more likely that antibiotics may instead provide a signalling role, within or across species. Antibiotics that are synthesized under laboratory conditions are produced at much higher concentrations than would appear in nature, and are therefore more suitable for treating clinical infections. There are many kinds of antibiotics, and antibiotic-pro-
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ducing organisms include for synthesizing peptidoglythe well-known fungal genus can, the major component Penicillium (which produces of the bacterial cell wall. penicillin) and members of This protein is known as the bacterial phylum Acine- penicillin-binding protein tobacter, which includes gen- (PBP). By inhibiting PBP, era such as Streptomyces and the formation of the cell Micromonospora. Streptomy- wall is prevented, leading to ces in particular produce a problems with bacterial cell wide range of Penicillium antibiotics, incolony cluding chloramphenicol, neomycin, tetracycline and clavulanic acid, while MiBacteria Inhibited cromonospora are the sources of aminoglycoside antibiotics. Antibiotics Bacteria used to treat infections usually work by inhibit- Plate showing the effects of penicillin-producing Peniing the protein cillium fungi on bacterial growth that is responsible
growth, division and eventually cell death via lysis. Resistance to antibiotics is natural, due to the need for antibiotic-producing organisms to survive the very antibiotics that they produce! The main strategies employed by resistant clinically-important bacteria include mutations/alterations of the antibiotic target (e.g. PBP, so the antibiotic can no longer bind to it), inhibition of the antibiotic protein (using molecules that resemble PBP in structure, thereby binding to the antibiotic in the place of PBP, and allowing PBP to function uninhibited), alteration of the antibiotic itself (via e.g. glycosylation or degradation, to prevent its activity), and removal of the antibiotic entirely from the bacterial cell (efflux). Resistance can occur through any one of these examples, or can more often be the result of combining such mechanisms. An infamous example of the first mechanism mentioned is the gene mecA, found in Staphylococcus aureus and Streptococcus pneumonia, which codes for PBP2A. PBP2A has a much lower binding affinity to penicillin and other similar antibiotics such as methicillin, giving rise to methicillin resistant S. aureus (MRSA). The acquisition of these resistance mechanisms is complex, but mainly occurs via horizontal gene transfer (the passing of resistance genes between bacterial species)
and, less commonly, through spontaneous mutations. In the first case, many genes derive from environmental bacteria (such as the acinetobacteria mentioned previously) that do not cause clinical infection, but are passed onto clinically important human bacteria that, after being subjected to the selective pressure of antibiotic treatement, survive and become resistant to that particular antibiotic. For example, the mobile ge(1-3) The regular cross-linking activity of PBP in netic element SCC- the bacterial cell wall. (4-5) The inhibition of PBP mec, which includes via binding of penicillin to the enzyme active site the mecA gene, is believed to methods, from a variety of have originated from animal sources, and affecting varistaphylococcal species, such ous populations worldwide. as S. fleurettii, before being Multi-drug resistance has also passed onto human S. aureus. been found in many cliniAnother more recent (and cal isolates of many common indeed worrying) example is pathogenic bacterial species, vancomycin-resistant MRSA, adding further complexor VRSA, a new ‘superbug’ ity and challenges for treatthat is resistant even to van- ment and finding alternatives. comycin, the last resort drug Yet, in the face of such a difor MRSA. This is believed lemma, barely any new antito have occurred over a 45 biotics have been introduced year period, whereby five re- into the clinic since the 1970s. sistance genes transferred to There are many reasons beMRSA from Streptomyces – a hind this. Firstly, many of the genus which, along with other existing antibiotics still work acinetobacteria, naturally pro- in the majority of cases and duces vancomycin. These are resistance is still a relatively among dozens of examples rare occurrence. Secondly, of antibiotic resistance, each increasingly tighter restrictransferred through different tions have been put in place in
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various stages of drug development, with antibiotics having to meet more criteria than ever before being successfully marketed and released to the public. Lastly, and perhaps most significantly, there is much more incentive for pharmaceutical industries to invest in drugs that are more profitable than antibiotics. Bacterial infections are usually acute, take a relatively short time to treat and are therefore not profitable in terms of the amount and cost of drugs required to treat an individual. In contrast, lifelong diseases, such as cancer and HIV, are much more profitable, and consequently have more focus placed upon them for pharmaceutical development. So, are there any solutions to the antibiotic crisis? In terms of drug development, huge advances have been made in terms of both the speed and sensitivity of genome sequencing techniques and bioinformatics, allowing more comprehensive and rapid searches for molecules produced by microbial populations (i.e. possible sources of new antibiotics) that would not have otherwise
been achievable in the ‘golden age’ of antibiotic discovery back in the early/mid20th century. Alternatives to antibiotics have also been considered, such as antivirulence therapy (which inhibits disease-causing traits of bacteria without affecting their survival, thereby removing the selective pressure) and bacteriophage therapy (the use of viruses that infect bacteria, known as phages, to treat bacterial infections). In particular, novel ‘natural products’ from both old and new sources of bacteria have also been hugely sought after, since the majority of antibiotics developed so far have been semi-synthetic derivatives of only a few natural antibiotic scaffolds that were discovered in the days of the golden age of antibiotics. New natural products would affect new mechanisms and molecular pathways not previously targeted, and could therefore form new classes of antibiotics. Many simpler methods have also been proposed that may have a profound effect on antibiotic resistance worldwide – in particular, limiting
Did you know?
the excessive and unnecessary use of antibiotics. Such problems may occur both in the clinic (through over-prescription) and in agriculture (antibiotics such as cephalosporins and vancoymycin are commonly added to animal feed to increase food production, giving rise to resistant bacteria that are subsequently passed onto humans who come into contact with these animals). On a smaller scale, simply completing a course of antibiotics, even if an individual feels better, may also reduce the chances of resistant bacteria developing within that individual and spreading throughout a community. There is hope, therefore, that new methods of treating bacterial infection may soon appear to combat the rise of antibiotic resistance and that resistance may even subside through correct global supervision and management. However, true results will certainly require swift action and increased attention from pharmaceutical companies – the crisis is indeed as much of a political issue as it is a scientific one.
“A rotationplasty is a medical procedure carried out when a portion of your leg (including the knee joint) needs to be removed, for instance when a tumour resides there. With the knee joint gone, the healthy lower leg is rotated and reattached to your upper leg, allowing the ankle joint to take over the role of the knee joint (and flex in the correct direction). Although the leg is shorter, having this mobile joint allows much more natural and easy movement when combined with a prosthesis.”
Cormac Kinsella
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Marvels
Pharmacogenomics Approach to Personalised Medicine
The potential of developing personalised medicine for selective subgroup of people is based on the concept of pharmacogenomics - which basically means the study of all the genes and variations of genes within individuals. This can identify specific genes which determine how your body responds to a drug. For example the drug – Warfarin, prescribed to patients with heart disease, is metabolised into active and inactive metabolites, the latter done by an enzyme called cytochrome P450. Patients with specific forms of the gene encoding cytochrome P450 would mean
they have less of the enzyme in their body. Because they have less of the enzyme, doctors would prescribe less of the drug to avoid side-effects. This is only one aspect of pharmacogenomics and other applications include genomic analysis of cancer patients, which allows doctors to identify the defective gene and therefore the defective protein encoded
Orchi Anannya
by the gene. Specific drugs to target the protein can then be prescribed. Genomic study of the population is however an expensive process and is currently limited to small scale clinical trials. Scientists agree that further research and funding for pharmacogenomics could lead to more personalised approach to medicine.
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