SYNAPSE THE SCIENCE MAGAZINE WRITTEN BY STUDENTS FOR STUDENTS
ISSUE 7 - April 2014 - FREE
Cyanide - eating Butterflies
The Science of being ‘Smashed’ | The Flesh Grazers Why Not Eat Insects? | Life on Exoplanets
EDITORIAL
The Synapse Team Felicity Russell Editor in Chief
Louisa Cockbill Vice President
Tom Stubbs
A Message from the Editor In Chief Welcome to the seventh issue of Synapse Science Magazine, the University of Bristol’s student science magazine. In this issue we cover more science topics than ever before ranging from the discovery of huge exoplanets to tiny cells with tails. 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 on synapse.scimag@gmail.com.
Secretary and Media Director
Oliver Ford
Senior Editor and Treasurer
Daniel Ward
Chief Graphic Designer
Nick Henden
Article Editors
Senior Editor and Graphic Designer
Molly Hawes
Managing Editor
Katherine MacInnes
Senior Editor and Publicity Officer
Toby Benham Senior Editor
Assistant Designer: Lexy Miles-Hobbs
Photographer: Jontana Allkja
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Abigail Wilson
Ines Wood
Akifah Mia
Isadora Viegelmann
Amisha Patel
Jade Low
Amy Newman
Jessica Towne
Andy Jones
Joe Connor
Celina Love
Katherine MacInnes
Daisy Dunne
Lewis Le Fevre
Daniel Stubbs
Lexy Miles-Hobbs
Davina Chao
Lucy Haras-Gummer
Eleanor Mortensson
Phillip Punter
Emma Mccarthy
Rachel Burgess
Georgina Winney
Rachel Greenwood
Hayley Ellis
Rosie Hayward
CONTENTS
On the cover
4. Cyanide-eating Butterflies 6. The Science of Being ‘Smashed’ 10. The Flesh Grazers 14. Why Not Eat Insects? 20. Life on Exoplanets
Features
14. Life on Exoplanets
ARTICLES
5. The Gunslinging Pistol Shrimp 6. The Science of Being
‘Smashed’ 8. Can Nanotechnology Cure the Common Cold? 9. A Secret Tail 10. The Flesh Grazers 12. Does an Aspirin a Day Keep Cancer at Bay? 13. MicroRNA 14. Why Not Eat Insects? 16. Finding it hard to give your heart away? 17. Parthenogenesis 18. Cells in the Balance 22. Polycephaly 23. Through the Eyes of a Chameleon 24. When Global Warming was Beneficial
COMIC STRIP 4. Cyanide-eating Butterflies
26. What’s with Chilli?
Join us online!
www.synapsebristol.co.uk @synapsebristol
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e Cyanide ating Amy Newman With its brightly patterned wings and delicate features, the Heliconius butterfly may seem like your average unassuming tropical bug, but this genus of insect has an extraordinary ability: it can consume cyanide. Found in Central and South America, Heliconius caterpillars hatch and feed exclusively on the leaves of Passionflower vines, such as Passiflora auriculata. All plants need ways to prevent them being eaten by herbivores and the passion vine is no exception, having developed a clever system for deterring would-be predators. The passionflower’s leaf cells contain poisonous cyanogenic (capable of producing cyanide) compounds, as well as the enzyme that activates them. Comprised of sugar molecules joined with a cyanide group, the cyanogenic compounds are inactive when alone. These two chemicals remain separate in different cellular components until the leaf is bitten into, causing them to mix and undergo a reaction which ends with the release of hydrogen cyanide gas. This is a good deterrent for other less resilient herbivores, as cyanide prevents respiration in cells by affecting their ability to utilise oxygen, causing paralysis- it’s understandable why this isn’t an appealing prospect for predators! However, the Heliconius caterpillars have an equally ingenious way of overcoming such concerted efforts from the passion vines to prevent them feeding. In a mechanism scientists haven’t yet fully discovered, they are able to inactivate the waiting cyanide and enzyme death trap, preventing the release of the noxious gas. It is known that this process involves swapping the offending deadly cyanide molecule for a harmless one with sulphur and hydrogen instead, using enzymes
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Bu tt e
rfl ie s
found in the caterpillar itself. Heliconiu s are the first example of insects which have this remarkable talent of being able to metabolise cyanogens and prevent the release of cyanide. Together with the Passiflora vines, they also act as an interesting example of coevolution, with the caterpillars and their host plants having each evolved comparable mechanisms in attempts to gain the upper hand in the struggle for survival. However, just because of their unique skill it doesn’t mean Heliconius have nothing to fear: some passion vines also grow hooked hairs in order to impale careless caterpillars, or even vary the shape or patterning of their leaves to try and trick the butterflies into laying their eggs elsewhere. Research on these butterflies’ mechanism for destroying cyanogens was published by Engler et al in Nature in 2000, and Heliconius is still the only example of a cyanide-metabolising insect today.
James Ormiston
The Gunslinging Pistol Shrimp For as long as sonar has been in use the ocean has been found to be a very noisy place. Surface waves, underwater earthquakes, volcanoes and even the breaking up of icebergs all contribute to the oceanic ambiance. But among these is a strange phenomenon which has wreaked havoc with naval monitoring for decades. The sound has been described as being akin to huge piles of sticks being moved around and broken. This snapping noise has been recorded at volumes as loud as 210 decibels, louder than a Space Shuttle taking off, and at a huge range of frequencies from tens of hertz to over 200 kilohertz. In fact it is so intense that it severely hampered the detection of enemy submarines in World War 2, as it was heard day and night without end. What could have been causing this enormous underwater racket? The answer came in the form of a surprisingly small crustacean known commonly as the “Pistol shrimp”. Measuring little more than a couple of inches and belonging to the family Alpheidae, these creatures were found to be creating the snapping noises with
their claws. Since some species of this large family are colonial, their combined din-making created a background crackle detected by the ships sailing above them. The staggering volume produced by these crustaceans is surprising enough, but recent studies have shown that production and use of the snapping is as impressive as the sound itself. The pistol shrimp earned its nickname from the way it utilises a greatly enlarged claw (which may be on either side in both sexes) to not only communicate with other shrimp, but to also stun its prey. The claw consists of the usual dactyl (movable) and propus (non-movable) components seen in most crustaceans. The key difference is not only the size of the two structures but also the presence of a kind of plunger attached to the dactyl, which fits into a socket in the propus when the claw closes. When prey is in range, the dactyl is “cocked back” to a near right angle and a spring-like muscular action brings it back down with tremendous force. The plunger enters the socket with such velocity that a jet of bubbles is fired out of the propus with enough energy to stun the target. The snap itself doesn’t arise from contact between the claw components; it results from the drop in water pressure caused by the speed of the dactyl’s plunger as it enters the socket, known as the Bernoulli Effect, this forms tiny air bubbles in the water that expand before violently collapsing. The process is described as “cavitation”. The pistol shrimp is yet another example of the extreme morphologies evolution is capable of producing...
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The Science of Being ‘ Smashed’ Alice Matharu
Have you ever been drinking heavily on a night out and wondered drunkenly, “I wonder which biochemical processes are taking place in my body right now?” Probably not. Ever wondered to yourself the next day, “Why did I do that?” Almost certainly. Well, here’s some of the science behind the effects of alcohol. What you do at the start of the night can affect how it ends. We are constantly told about the importance of eating before drinking heavily in order to ‘line the stomach’, but many people don’t take this saying as literally as they should. The stomach has a protective covering known as the epithelial lining which alcohol damages. Having food before a night out helps protect this lining and reduces the speed at which alcohol is absorbed into the bloodstream. This is because when enzymes break down alcohol in the liver, the chemical acetaldehyde is produced. This chemical is thought to be the main cause of hangovers, but eating food helps to reduce its formation in your stomach.
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Why do you do things you regret? This is all to do with the part of the brain known as the cerebral cortex. People feel less inhibited because alcohol supresses what is known as the behavioural inhibitory c e nt r e . You bec o m e less aware of the consequences of your actions as processing sensory information takes longer, and it becomes harder to think clearly. Other parts of the brain are affected at the same timefor instance, when alcohol takes effect on the cerebellum, we experience the clumsy, staggering part to the night as our movement and balance is affected.
The phenomenon of “beer goggles” When excess alcohol is consumed, perspective of what is attractive changes to the “wearer” of the goggles. Research has found that people with symmetrical faces are perceived to be more attractiveit is subconsciously seen as a sign of good genes and health. Studies at the University of Roehampton have shown that people who have consumed alcohol find it more difficult to tell whether a face is symmetrical or asymmetrical, and as a result they become attracted to people besides who they normally would.
Cheesy chips, anyone? It’s standard to finish the night with something high-calorie and greasy, it’s what your body is craving! Dehydration occurs as the hormone that regulates urination is inhibited, and a craving for salty food is a natural response to dehydration. By consuming fat you are actually slowing down the transportation of ethanol in the bloodstream whilst also delaying the psychological effects of alcohol. The consumption of alcohol leads to increased production of the brain chemical galanin, which increases our appetite for fats. But watch out, it’s a vicious cycle- whilst alcohol increases production of galanin, galanin increases thirst for alcohol.
Can’t remember what happened the next day? The hippocampus is part of the brain responsible for memory consolidation. With excessive alcohol it cannot carry out its usual function: consolidating short-term memories into long-term memories. This means that whilst a drunken person can maintain a fluent conversation as if they were sober, they’re likely to struggle to remember events that happened a few hours before, since most casual conversations don’t demand that participants recall events for more than a few minutes.
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Can Nanotechnology Cure The Common Cold? AAACHHOOO! As if 9am lectures, impending economic crises and running out of butter weren’t enough to worry about; it’s the middle of winter... and you have a cold (sniffle). Time then, to don the thick socks, brew a steaming mug of Lemsip, get into bed and watch Peep Show. Or is it? Recently, a group of molecular virologists in China believe they may have found a solution: Nanotechnology - the science of all things really, really small. In a paper published in Nature (449, July 2013), Masaru Kanekiyo and his team discuss their fascinating breakthrough: Using a protein called “ferretin” to mimic particular protein structures of the H1N1 influenza virus in order to develop a vaccine against it. They found that ferretin protein is able to naturally form nanoparticles in vivo, and that these particles, if attached to particular proteins present on the surface of an influenza virus, were able to induce an immune response against H1N1 influenza in mice. One effect of this immune response is to generate so-called ‘memory T-cells’ in the body. It is these cells that ‘remember’ the infection so that it can no longer infect ‘protected’ people (those that have the memory T-cells because they have been previously infected). To induce an immune response, and thus generate memory T-cells, the team attached ferretin to haemagglutinin, a surface protein on influenza viruses. The team found that inoculation with these ferretin-haemagglutinin proteins produced a T-cell response that was ten times greater than the immune response generated
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by our current vaccines. In other words it would appear that this new treatment is ten times more effective than those we currently use. Impressive stuff. But in fact, this new treatment may have even further implications in our fight against the common cold - and here’s where it gets complicated. To date, our difficulty in producing a vaccine against influenza owes to the fact that the virus is constantly mutating and changing. It is these changes that mean our immune system fails to recognise new ‘mutants’ of influenza virus, and explains why we usually get a different ‘cold’ each winter we have essentially been infected with a new form, or serotype, of influenza. Interestingly, it was found that ferretin-haemagglutinin proteins were able to induce an immune response, in the form of ‘neutralising antibodies’, against conserved or constant structures of influenza - structures that don’t mutate or change seasonally. The team hopes that this breakthrough could be a key step in the development of a universal influenza vaccine: A vaccine that would be effective against all strains and seasonal ‘serotypes’ of the common cold.
Michael Whitehead
A Secret Tail Pippa Sinclair Consider the humble sperm cell, characterised by its powerful flagella. Then consider the ciliated cells that line your small intestine, oesophagus and the fallopian tubes, and it becomes evident that many of your cells have a tail. Ciliated and flagellated cells are prime examples of this, but it doesn’t end there - you may be surprised to find out that over 99% of known types of human cell possess a tail!
Over 99% of known “types of human cell possess a tail! ” From protozoa to animals, just about every kind of organism with complex cells have cell tails with a common structure. Most seed-producing plants do not produce any cells with a tail but they do have tail-related genes, which suggests that the last common ancestor of eukaryotic organisms possessed a beating tail.
(strangely!) nerve cells. Although structurally similar to flagella and cilia, a lack of central microtubules sets primary cilia apart and may explain why primary cilia don’t move independently. When primary cilia were discovered by Alexander Kovalevsky in 1867, it was suggested that they were merely vestigial. In the 1990’s the question of their purpose still remained! Evidence now suggests that primary cilia are key coordinators of signalling pathways during development and in tissue homeostasis. If defective they can cause diseases and developmental diseases such as diabetes and blindness. These tiny tails are therefore not only prolific but essential for maintaining our health, perhaps surprising since they’ve been such a secret for so long.
– The motive tails (flagella) of Gram-negative Bacteria rotate to propel the bacteria through fluids.
Many cells in a human do not appear to possess either flagella or cilia, for example skin cells. However, these cells do have non-moving tails known as “primary cilia” which have been found in just about every cell type in the human body, including
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Flesh Grazers The
Ask any adult around the world and the chances are they’ve heard of the infamous Tyrannosaurus rex and of its bone crushing bite employed against contemporary herbivores such as Triceratops. However, since 1995 it has been well accepted in the scientific community that there was at least one other giant carnivorous dinosaur that rivalled or even exceeded Tyrannosaurus in size. This dinosaur was called Giganotosaurus carolinii and belonged to a family of therapod dinosaurs known as Carcharodontosauridae or the ‘shark toothed lizards’. This family consisted of several huge flesh devouring titans such as Acrocanthosaurus, Carcharadontosaurus and Tyrannotitan which hunted and lived in an entirely different way from any creature we know on earth today, and fed upon the largest animals to have ever walked the earth. The carcharodontosaurid dinosaurs are often called ‘flesh grazers’ owing to a remarkable style of feeding which allowed them to prey upon dinosaurs over ten times their own size. To get an idea of how they managed this we must first take into account the prey these creatures fed upon. Weighing in at 79 tonnes, the titanosaur Argentinosaurus was one of the most monumentally enormous creatures to ever walk the earth and a staple prey item of carcharodontosaurid dinosaurs such as Mapusaurus (a slightly smaller relative of Giganotosaurus that lived alongside Argentinosaurus) or possibly Giganotosaurus. It is estimated that such an individual would contain: 11 tonnes of bone, 3.5 tonnes of
Rob Cooper
blood and plasma, 4 tonnes of skin, 15 tonnes of fat and 39 tonnes of meat and soft tissue. Argentinosaurus’ skeleton alone weighed more than an adult Triceratops or Tyrannosaurus. Could Mapusaurus or possibly the even larger Giganotosaurus have brought down such an enormous herbivore by themselves? Considering that the larger Giganotosaurus was estimated at between 12-14.5 meters with weight estimates up to 8 tonnes it seems unlikely that either of these predators could have, by themselves, taken down the sauropods that were, at least 10 times more massive than they were. While sauropods had an obvious weakness of a very slender neck and small head it seems extremely unlikely that even the giant Giganotosaurus could have managed to reach these weak points. It’s possible that several Mapusaurus could have worked together to bring down their monolithic prey by a brutal war of attrition but considering the relatively meagre size of Mapusaurus’ brain (about half the size of T. rex’s) it seems more likely they simply mobbed their prey en masse. This is supported by a remarkable find in 1995 in South America where hundreds of bones from various different individuals of Mapusaurus were found jumbled together.
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Although, it is plausible that a flash flood or other similarly catastrophic event could have led to this mass grave. Instead it seems the key to their success was tied up in their skull morphology. Carcharadontosaurids such as Mapusaurus had relatively much longer skulls than the fabled Tyrannosaurus with skulls even reaching 2 meters long. These elongated skulls were more lightly built than those of Tyrannosaurs with more openings in the maxillae bone and large nasal openings. The lighter skull also meant that the bite force carcharadontosaurs could exert was much less than Tyrannosaurs although they could open their mouths to an astonishing angle unseen in most therapods. The teeth were also completely alien from those of Tyrannosaurus, being shorter and more blade like suiting an entirely different purpose. The teeth had a very thin cross section and much finer serrations that would have aided the dinosaur in being able to slice through meat with ease but may have made it difficult to crush bone in a similar manner to tyrannosaurs. The long lightweight skull with flesh slicing teeth implied a very different style of hunting to that of other carnivores both present and past. A style that did not necessitate the death of the prey. The knife like teeth and immense gape of Mapusaurus would have been perfect tools for eating titanic sauropods‌ Alive. This strategy was known as flesh grazing.
Imagine, if you will, a herd of Argentinosaurus each one dwarfing the predators that beset it. The sheer size of these animals means that a group of relatively more nimble Mapusaurus would have had little difficulty tearing chucks of flesh from the lumbering sauropods flanks and sating its phenomenal appetite without having to kill a single animal. It is indeed a bloody and morbid picture but it is a strategy that makes a lot of evolutionary sense. Why kill such a dangerous animal when you can simply feed from it and then leave the population intact in order to proliferate and supply more food to help ensure the survival of the genes contributing to this feeding strategy? Unfortunately we can never categorically state how any of these extinct giants lived but the hypothesis of pack hunting and flesh grazing offer interesting interpretations of the evidence we have available. A modern analogy to flesh grazing can be seen today in species such as the Komodo dragon which will happily feast on living prey once the prey has collapsed from blood loss thanks to the anti-clotting agent in the dragon’s saliva. The giant carcharadontosaurids simply took this maxim to the extreme in an evolu-
successful land predators of all time.
tionary leap to become, at least where size of the prey is concerned, the most
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DOES AN
KEEP CANCER AT BAY?
Gabriella Beer The British media have been speculating over the potential effectiveness of Aspirin in treating cancer. Aspirin, more commonly known in the lab as acetylsalicylic acid, has anti-inflammatory properties that can be traced back in time as far as 400 BC. Hippocrates was known for willow leaf concoctions, recommending them to women in an admirable attempt to alleviate the pains of childbirth. Unbelievably, this must have been effective, as utilisation of this medicinal plant proliferated across the world, globally decreasing the symptoms of fever and pain. However, it wasn’t until 1971 that Felix Hoffman decided to sit down and analyse the molecular properties of this miraculous compound, deciphering an explanation for this drug’s analgesic virtues. Molecular analysis found that the miracle molecule disrupts inflammation, a physiological process induced by the human body to protect against harm. Cyclooxygenase, an inflammatory enzyme, is inhibited by acetylsalicylic acid, preventing the synthesis of prostaglandins which are fundamental to the inflammatory response. Studies have claimed that cyclooxygenase is overexpressed in many cancers, most significantly cancer of the bowel. In 1983, W.R Waddell made an intriguing observation concerning sulindac, a non- steroidal anti- inflammatory drug (NSAID) and patients with familial colorectal poly-
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posis, an inherited disease characterised by the presence of multiple polyps in the colon and tumours adjacent to the colon area. Patients showed a significant reduction in the number of colon polyps after only four months of minimal NSAID treatment. Since then, numerous epidemiological studies have proved taking NSAIDs such as aspirin decreases the risk of developing more prevalent cancers, such as breast and lung. One trial, sparking particular interest, found that aspirin usage in heavy smokers was strongly associated with reduced lung cancer risk. Hysteric media coverage nagging the public to acknowledge factors such as smoking as common causes of cancer may seem by now tiresome and obvious. There is danger of scientists being accused of promoting a tedious and over-cautious outlook on life, perhaps even tiptoeing around the unavoidable. However, with this latest research, it’s not entirely absurd to predict the development of an ‘anti- cancer supplement’ in the near future. Admittedly, there is great requirement for isolation of further cancer-preventive molecules, but a single tablet to decrease the risk of cancer development seems a much more convenient and less dramatic lifestyle adaptation to adopt. We are creatures of habit after all- maybe the Ancient Greek who simply brewed tea to cure headaches brewed a little more than he thought; the potential to save millions of lives.
MicroRNA
Jontana Allkja
An exciting new field in genetic research The first microRNA to be discovered was in 1993 by Victor Ambros, Rosalind Lee and Rhonda Feinbaum in C.elegans development. MicroRNAs are more commonly referred to as miRNA. They are very short, approximately 22-nucleotides long, non-coding sequences involved in post-transcriptional regulation. By complementary binding to the untranslated regions of mRNA which are found before the start codon and after the stop codon miRNAs can silence the gene and prevent its translation. miRNAs are present in all human cells and they target approximately 60% of all genes. It took a further seven years for the second microRNA sequence to be discovered and since then, the amount of research into the field has increased to help further our understanding of, their functions, properties and potential role in various diseases. Since the beginnings of the millennium, over 4000 miRNAs have been discovered in eukaryotes of these 700 are present in humans. Most miRNAs contain their own gene promoter and regulatory regions and they are found in intergenic regions or intron regions of the mRNA and very rarely in exon regions. While miRNAs are usually involved in inhibiting protein translation, in some cases they can cause DNA methylation which affects the expression of the target genes. Recent studies have shown that miRNAs have a variety of cellular functions such as cell differentiation, proliferation, apoptosis, haematopoiesis and lipid morphogenesis.
With the considerable effect of miRNA on cellular function, miRNA malfunctions can be associated with various diseases such as the development of cancer. In a particular study, mice were used to model cancer. The results showed that those who produced a form of miRNA found in lymphomas, developed cancer within 50 days while those without the miRNA alterations lived for over 100 days. Other studies have shown that miRNAs have the ability to inhibit the E2F1 protein which is directly involved in cell proliferation regulation. It has also been shown that miRNAs can serve as a guideline for the diagnosis of cancers as their activity can show where the cancer originated first, thus enabling doctors to create targeted treatments based on the original tissue type. Other research groups have also discovered a link between miRNAs and other diseases such as Schizophrenia and cardiovascular diseases. In regards to the latter, using expression studies it was shown that miRNAs play a crucial role in heart development and that different heart diseases have different levels of miRNA expression. As a result of miRNAs playing a crucial part in the development of certain diseases, they have great potential in being used as targets in the treatment of these diseases. This could revolutionise the way in which we treat certain diseases such as cancer and is the reason for why a great deal of funding has been going into this field recently.
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Why Not Eat Insects?
With ever-increasing concerns over food security, world hunger, and climate change, the UN is encouraging us to eat insects. In 2012, the Food and Agriculture Organisation of the United Nations published a report describing insects as “Healthy, nutritious alternatives to mainstream staples such as chicken, pork, beef and even fish”. But what are the benefits of eating bugs? What many people may not realise is that eating insects, or entomophagy, is a common practice around the world. Around 2 billion people consume insects regularly and some are even considered delicacies. Leafcutter ants are traditionally eaten in Colombia, witchetty grubs in Australia, and caterpillars called mopani in South Africa.
Nutritional benefits Many insects are good sources of protein, calcium, iron, and zinc. Compared to beef, mealworms contain less fat, and have a higher essential fatty acid and vitamin content. The high iron content of some insects could help to prevent anaemia in developing countries, where one in two pregnant women and around 40% of children are anaemic. Entomophagy may also have health benefits for some people. Studies have shown that chitin, a protein that is a major component of the exoskeletons of arthropods, may have immunological benefits, such as reducing allergic reactions in some individuals by stimulating both innate and adaptive immune responses.
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Social benefits As well as benefiting people nutritionally, insect farming is low tech and low investment. People from underprivileged social groups may even be able to set up their own businesses. Farming insects could be kinder and more ethical than farming other, more “complex” animals. Obviously insects may be kept in much smaller enclosures than larger animals, and many species such as locusts naturally gather in large closeknit groups.
Environmental benefits It has been argued that agriculture is the greatest contributor to human-induced climate change. Around 70% of agricultural land is used for livestock, but this could be reduced by replacing traditional livestock such as cows and pigs with crickets and grasshoppers, as they require less land and water. Insects release fewer greenhouse gases, such as methane, and other waste products like ammonia. Manure is also an issue when farming cattle and pigs, as it contains contaminants and pathogens. In 1991, a study found that
crickets need 12 times less feed than cattle and 4 times less than sheep. This is because they are ectothermic, and don’t spend lots of energy producing body heat like mammals do. To reduce food costs even further, insects can also be fed on organic waste. Entomophagy needn’t replace other livestock completely, and may even be beneficial to farming other animals.
Livestock feed prices are always increasing, with the most expensive feeds being soy products, fish meal, and meat meal. The cheaper insect-based alternatives could replace expensive feedstuffs entirely in some cases. Silkworm pupae, which are already farmed for silk production, could replace fish meal in poultry diets. Insects are already used as complementary feed for poultry, which is part of the normal diet for chickens and other birds. The immunological benefits of chitin could apply to poultry as well as people. This could remove the need for antibiotics to be administered to livestock, which would reduce cases of antibiotic resistance in human pathogens.
Challenges The greatest issue facing insect farming in the West is probably persuading people to overcome their feelings of disgust towards eating insects. In Australia, the New South Wales Department of Primary Industries proposed renaming locusts as “sky prawns” and even wrote a cookbook called Cooking with Sky Prawns. Which raises the question: Why do we consider crabs and shrimp to be edible, and even luxury foods, but not other arthropods such as insects? There are many reasons, including the belief that insects are unhygienic and that eating them is “primitive”. Perhaps the solution is to make insects fashionable. If Gordon Ramsay told you that eating insects was a great idea, would you? Attempting to persuade westerners to eat insects is nothing new, however. In 1885, the British entomologist V. M. Holt published a booklet entitled Why Not Eat Insects? He suggested that a good way of dealing with insects that are agricultural pests and damage crops was to eat them. Modern farming methods and negative attitudes towards entomophagy have had an impact on those who do eat insects. In Mali, children would often catch and eat grasshoppers. Since 2010, however, they have been discouraged from doing so by their parents due to concerns about pesticides. The pesticides were introduced by western advisors to use on nearby cotton fields. So could you be persuaded to try grilled grasshopper? There is a long way to go to convince westerners that making a meal of bugs is a good idea, but the spread of information on the nutritional and environmental benefits may change that.
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Red: Female Blue: Male
Evidence suggests that perfect couples have the ability to synchronize their heartbeats.
A couple’s heartbeats
From classical poetry to booming club music; across centuries the human heart has been our international symbol for love. Finishing off each other’s sentences is so sickly sweet and having the same favourite hot beverage is such an amazing coincidence, but is there a way of proving that your other half is the ‘ONE’?
Finding it hard to give your heart away? Scientists have found that some couples have the ability to synchronize their heartbeats. The aim of the experiment was to determine the linear association of heart rates between two individuals. Calculating whether a linear relationship occured solely by measuring heart rates was not possible for two reasons. Firstly, there is a difference between male (67-70 bpm) and female (70-73 bpm) heart rates. Secondly, each individual has a self-regulatory system controlled by the autonomic nervous system (ANS), which regulates most of the body’s internal functions. The activity of the ANS varies depending on an individual’s moods and emotions and this in turn results in variations in heart rate. An algorithm was used to filter dependent emotional regulatory systems and variations due to sex to produce graphs. To conduct the experiment, 32 heterosexual couples were wired up to measure respiration parameters, allowing them to calculate each individual’s oscillation and respiratory rate. Couples were asked to complete a series of
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tasks, one of which was to simply look at one another. This was to encourage ‘co-regulation’; a term used to describe when a person unconsciously mimics the partner. The experiment was then repeated with the couples being split up and tested with another person that they were not in a romantic relationship with. The results showed that couples were significantly more likely to synchronize their breathing rates and heart rates with one another in comparison to non-sexual partners. Interestingly it appeared that women were more likely to adjust their heart rate to their partners. This could be due to the fact that women are more empathetic than men and therefore adjust more in a relationship. Being a stickler for romance, it is nice to think that it has been scientifically proven that your heart can tell you who that special someone is. However, personally I wouldn’t recommend using this as a form of compatibility test on your first date!
Chesky Baillieu
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Parthenogenesis A Guide To Self-Reproduction
New Mexico Whiptail Lizard
From a young age I was well aware that every species contained both males and females. It was in my late primary school years that I learned the truth about the ‘birds and the bees’. However it wasn’t until a number of years later that I discovered you didn’t need the bees at all. Animal documentaries introduced me to a species of lizard called the New Mexico Whiptail Lizard or, as it was rather crudely nicknamed, the “lesbian lizard”, a species which comprised solely of females. How was the species supposed to reproduce without males? That answer was a process called parthenogenesis, where a female can produce perfectly healthy young without male fertilisation. The New Mexico Whiptail has mastered the art so well that all males have been driven to extinction. This process of parthenogenesis has allowed them to preserve the genes that they have evolved over thousands of years to live successfully in the Arizona desert. However this comes with a heavy price. The young are clones of the mother and so variation is almost non-existent in the species. Only ‘DNA copying errors’ produce variation within the genome and that, in almost all instances, has no effect at all on the lizard. This lack of genetic diversity leaves them incredibly susceptible to disease and climate change. Without any males to create any genetic variation within the species, there is no ‘survival of the fittest’. Also the lack of males means that the females are forced to reproduce
Jack Hales
this way hence the name, ‘obligate parthenogenesis’. So how does it work? Well, the process is called ‘Automictic Parthenogenesis’. During this process meiosis occurs naturally, but in the final stage two of the egg cells merge together to create a diploid cell. This diploid cell has all the nutrients and all the information to grow into a full organism. However, instead of one set of chromosomes coming from each parent, both sets of chromosomes come from the mother. This produces young with an exact copy of their mother’s chromosomes known as a ‘full clone’. Depending on the species and the chromosomal system that has developed, there’s also the capability that males can be produced instead of females by ‘Haploid Parthenogenesis’. In Honeybee colonies, the Queen lays thousands of eggs a day and each male is produced by parthenogenesis whereas every female is produced by sexual reproduction. This is because males have the sex chromosome ‘X’, and females have ‘XX’. When the Queen reproduces by parthenogenesis her eggs do not require the diploid number and so there is no ‘re-joining’ of two egg cells. As there is only one sex chromosome present, it must be ‘X’ resulting in a male; known as a ‘half clone’. Parthenogenesis has been induced in a few small mammals, however it isn’t yet a natural process for our kingdom so even though dating can be a pain at times, it is, I’m afraid, still our only option.
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ARTICLES
Cells in the Balance:
A Story of Death and Survival In the United Kingdom, we are living longer and longer. An individual born into positive conditions can now expect to live well into their 80’s. Of course this is not a bad thing, but with increasing age comes the inevitable onset of disease. While it is clear that there is an increased risk of developing both cancer and Alzheimer’s in old age, the correlation between the two is only just being characterised. If you develop one, you are extremely unlikely to develop the other. Numerous studies have shown this inverse relationship, the most recent of which (published in the British Medical Journal) claimed that people with cancer were 43% less likely to develop Alzheimer’s, while those suffering from Alzheimer’s had a 69% decreased risk of developing cancer. But why exactly is this? Although both diseases are linked to ageing, they have dif-
Fig. 1 18 | SYNAPSE
Joe Connor
ferent pathologies: while cancer is linked to uncontrolled cell growth, Alzheimer’s sees significant death of cells in the brain. It is believed that the progression of both diseases is linked to the same process – the control of progression through the cell cycle. The cell cycle is the term given to the life cycle of the cells in the body, comprising the active stages of the cell’s life, when it is performing its function, as well as the periods during the cell’s life when it is preparing to divide, and indeed the division itself [Fig 1]. It is key that this cycle is tightly regulated, as its over-stimulation or cessation can lead to these destructive diseases. One of these control points has been linked to why it’s so unlikely to develop both cancer and Alzheimer’s. It involves the tumour suppressing gene,
TP53, which controls the passage from G1 phase of the cell cycle to S phase, at which point the cell commits to replicating its DNA. This gene is pivotal in the destruction of damaged cells. As we get older, our cells accumulate damage – such as errors in DNA replication that aren’t corrected and the shortening of telomeres. Cells that accumulate damage like this are susceptible to becoming cancerous and it is in the prevention of this that p53 steps in. Upon DNA damage, p53 is uncoupled from its inhibitor, Mdm2, and can perform its effector functions. These include the stalling of the cell cycle, which is ensured by the p53-induced activation of p21, which binds to and inhibits the complex that allows progression into S phase, and the induction of apoptosis - the controlled death of the cell [Fig 2]. So, we have identified that over their life time, our cells accumulate damage. This can be from natural senescence, or from external events such as UV exposure. We have also shown how tumour-suppressing genes such as TP53 can prevent these cells from initiating disease, by either halting these cells’ progression through the cell cycle or controlling their destruction. But what if this happens too readily? This is how degenerative diseases such as Alzheimer’s arise. Research has linked up-regulated p53 activity with neurodegenerative diseases. This is thought to be because p53 can initiate phosphorylation of tau proteins, which stabilise microtubules (the scaffold that runs throughout cells and organises their contents). These tau proteins are found primarily in neurones, and once phosphorylated they can
Fig. 2
form tangles. These tangles and misfolded proteins create the highly insoluble plaques associated with neurodegenerative disease. Add to these modifications of tau proteins the apoptotic properties of p53 and you can get further degeneration of neuronal tissue, as neurones and other cells of the central nervous system are killed. So, how can we explain the high incidence of cancer and Alzheimer’s individually, but the low incidence of the two together? It is because the two diseases arise from two extremes of the same cycle malfunctioning. Cancers arise when the genes that normally ensure the stalling of damaged cells in the cell cycle, which can result in their destruction, become inactivated. However, it is the up-regulation of these genes that lead to neurodegenerative diseases such as Alzheimer’s – through tumour suppressor gene mediated phosphorylation of key proteins and the overactive killing of neuronal cells.
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ARTICLES
Life on Exoplanets
Laura Rogers
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G
rasp a handful of sand. Let it fall through your fingers, and think ‘there are more stars in the universe than there are grains of sand on the Earth’. When you ponder the enormity of this claim, it is hard to justify the colossal size of the universe. Thinking deeper, you begin to understand how small our sun, our Earth and we are. If every grain of sand were a star, you can imagine how many planets are out there. It is predicted one in six stars could have an Earth-sized planet orbiting it. If even one of these billions of planets had the right conditions for life, there could be a whole other life form out there without any knowledge of us.
Planets which orbit a star that is not our sun are called ‘exoplanets’ (or ‘extrasolar planets’). It may be assumed exoplanets are easy to detect, however, as they do not radiate their own light, they are difficult to spot. Specialised techniques have been developed to understand how they affect the star they orbit. The radial velocity method studies how the star moves due to the attraction caused by the gravity of an orbiting planet. The speeds the star travels towards and away from the earth, the radial velocity with respect to the earth, can be used to calculate the planet’s mass. An alternative method is to study the light from a star: the transit method. If the light received slightly decreases for a period of time, it is normally due to a planet passing in front of it. Another technique utilises the fact that planets emit infrared radiation, and can be spotted using specialised telescopes.
On October 22nd 2013, astronomers exceeded an astonishing count of 1000 detected exoplanets. Of these, it is predicted around 12 could support life. To support life, a planet must not be too hot or too cold, so that liquid water can be found at the surface. It is vital to have essential metals and micronutrients to construct and maintain an organism’s body. It must be orbiting a star which radiates enough energy for life processes to occur on the planet. Also, it must have an atmosphere that can trap heat and protect the planet from damaging radiation. Kepler 62-e is the most Earthlike planet found - with 83% similarity, it is a good candidate to host life. It was discovered using the transit method and is an important discovery in attempting to find life out in deep space.
With technology ever developing and scientific curiosity ever increasing, who knows what secrets we will uncover about the mysterious, dark and enigmatic universe in which we live.
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ARTICLES
I
want you to imagine a beast. This beast is half-dragon and half water-deity, with a body encrusted in reptilian scales, uniformly arranged as the waves from whence it emerges. A beast, entrusted with the task of guarding the underworld; as black as the night and as colossal as a mountain. With poison-rich blood and breath so potent, it can kill a man. And, of course, its most distinguishable feature: the writhing mass of necks emerging from its torso, each with a very hungry, regenerative mouth to feed. Admittedly, imagining the Linnaean Hydra is far easier than conquering it – you just need to ask Hercules. Yet, could you picture an organism, equipped with multiple heads, in modern society? Literally meaning ‘many-heads’, polycephaly is the occurrence of an organism developing more than its one – usually adequate - single head. Though many heads may be possible, most organisms born with polycephaly are bicephalic (two-headed) or tricephalic (three-headed); as these are most viable. Polycephaly is not a common occurrence, but is definitely not unseen (around 1 in every 10,000 births) – leaving the said organisms fetching large price tags if sold. Reports crop up all over the globe, from breeders and owners alike. It isn’t limited to any specific groups of organisms with cattle, kittens, reptiles and dogs all appearing in the records. Of course, hum,ans are not without their instances too – although, for this, the focus is on animals. So what causes this natural phenomenon? Unfortunately, the cause is not being the offspring of the mighty Typhon, the ’Father of all Monsters’.
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Polycephaly:
The Science behind Hydra
Sam Matchette
The answer is, in fact, far more simple and something that we as society have accepted for a long time - think conjoined twins. Upon fertilisation of egg by a sperm, a zygote is formed. This zygote can spontaneously divide to form monozygotic (identical) twins, at which point they separate and continue development until birth. In the case of conjoined twins, the zygote divides to form identical twins, but does not fully separate – seemingly due to similar stem cells from both twins sticking together. The point at which they are stuck is variable; although many are variations of thoracic. In the case of polycephalic individuals, the division and stick occurs at the neck, with only the head of the second twin being formed. Unfortunately, the old saying of ‘two heads are better than one’ is not valid in these unique cases. Treated as one animal with two functioning brains, an issue arises regarding internal decision making. With the ability of individual movement and choice, the two heads will literally argue with each other. Occurrences of snake heads turning and attacking each other have even been reported. Not only this, but in larger organisms, such as cattle, the sheer weight of a second head can prove too much for the developing legs – leaving them unable to walk. It is due to this uncoordinated instability and unpredictability which leaves these organisms with very little chance in the wild. In captivity however, they can have surprisingly long lives depending upon care and species. One shared stomach allows each individual to independently contribute to drinking and eating to the metabolism requirement for double ‘brain power’. Despite the lack of coordination though, and especially in cases of bicephalic snakes, the result is truly mesmerizing. The movement is hypnotic and spectacularly absorbing. It’s for this reason that I wanted to explore this mythical concept; bringing the likes of the Linnaean Hydra and J.K Rowling’s ‘Fluffy’ to life. Though, it may take a little while longer to scientifically explain Nickelodeon’s ‘Catdog’…
Through the Eyes of a Chameleon Visual cues in prey capture and predator avoidance Having recently travelled to the island of Madagascar, the world’s chameleon hotspot where over half of all chameleon species reside, I have found myself entirely enthralled by those bizarre eyes of theirs. A chameleon’s eyes move independently of one another and allow 360 degree panoramic vision due to their position on conical turrets; an especially useful trait for the capture of evasive insect prey. These reptiles are also the only vertebrates with the ability to focus their eyes monocularly, thanks to a combination of a negative concave lens and a positive convex cornea. Rapid focusing is achieved by striated, rather than smooth muscle surrounding the eye. So how do chameleons control their complex visual machinery? The two eyes work entirely independently whilst scanning for prey (or potential predators), but the moment an unlucky insect is sighted by one eye, both eyes swivel to focus, still independently, on the target. This system allows incredible depth perception, enabling the famous chameleon tongue to strike out at its target with unbelievable accuracy. Independant vision can also be used to scan the environment for predators whilst hunting down prey, a necessary ability in the wild rainforests of Madagascar! Apparently making chameleons look fantastically crazy is not a good enough reason for this complexity, and it is thought that these eyes allow minimal head movement when scanning for predators, as well as to avoid startling prey. Chameleon eyes are thought to be an example of the transition to stereopsis (depth perception caused by the combined vision of two eyes) and binocular vision, which is seen in many species including ourselves; as uninteresting our own eyes may seem in comparison to a chameleon’s!
Bethan Manley
©Paramount Pictures SYNAPSE | 23
ARTICLES
When
Global Warming Was Beneficial
Global warming: there’s no doubt it’s one of the hottest topics around. Everyone has an opinion on it: whether it’s actually occurring, its severity and what’s actually causing it. Whatever your views, there’s no doubt that a global warming event could have severe impacts upon life on this planet. However, rather ironically, it was potentially global warming that helped make it possible for life on Earth to survive and flourish. To clarify, global warming is the overall rise of average temperatures on Earth. The possible mechanisms behind this are plentiful, one of the main drivers being the greenhouse effect. Certain compounds such as carbon dioxide, nitrous oxide and even water vapour, due to the nature of their bonds, have the ability to retain some of the thermal energy radiated from the Earth’s surface. The greenhouse effect is actually very helpful, without it temperatures on Earth today could be 33°c lower on average. So, life today would be completely different or barely exist without the greenhouse effect, but unfortunately due to the media most people take it for granted and even loathe it. The warming of the planet is therefore a vital process, and was even more important during the fragile evolution of early life. The Earth is approximately 4.5 Ga (billion years old), and during its long history it has endured many climatic changes. The earliest evidence for life on Earth comes from around 3.5 Ga, in the form of fossilised accretions of bacteria
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Simon Thomson
called stromatolites. These are immensely important in that they provide the oldest evidence for life on Earth and give us clues as to how the first life forms evolved. But in what kind of environment did they survive?
Life today would be “completely different or
barely exist without the greenhouse effect
”
The dilemma here is known as the faint young Sun paradox. During the Archean era (3.8-2.4 Ga) during which these stromatolites lived, the strength of the sun was around 20-30% weaker than what it is today. This would have meant the Earth should have been a frozen wasteland covered in ice sheets and glaciers; needless to say an inhospitable place for the majority of life forms. However, there is no current evidence in the geologic record to suggest such a large coverage of ice existed at this point in time; in fact the evidence suggests a large abundance of water. So what could have caused the world to be so warm? One possible answer comes from (you guessed it) the greenhouse effect. The Earth’s atmosphere at the time was likely a mix of methane, ammonia and other toxic gases. One major theory relies on carbon dioxide being present in large quantities, which could have resulted from the higher levels of volcanic activity at the time. The evidence for this is unfortunately conflict-
ing. Due to the rarity of carbonate rocks it is likely that the oceans of the time were fairly acidic; a direct result from carbon dioxide dissolving in the oceans and therefore not being present in the atmosphere. Even so, the concentrations required would have to have been a thousand times greater than at present. The most accurate data set comes from ancient fossil soils which suggest only modest levels during the Archean era. However, new data taken from bubbles in hydrothermal quartz may suggest levels to be higher than previously thought. Some research states that carbonyl sulphide may have been present in quantities sufficient enough to make up for the lack of CO2. Other greenhouse gases such as ammonia and methane were unlikely to have played a role as they are fairly fragile, and could have been destroyed by the incoming ultraviolet (UV) radiation. The ozone layer which absorbs UV radiation had yet to be formed and interestingly enough, it was the stromatolites and their relatives which produced the free oxygen which enabled this layer to form. One more ‘out there’ theory suggests that the Earth could have been several million miles closer to the Sun, therefore warming the planet to sufficient levels. It proposes that the Earth may have migrated from the sun over time through a process called planet-planet scattering. This speculates that two proto-Venus planets existed at one point and went into a chaotic and unstable phase, crossing Earth’s path and boosting us to our
familiar orbit. The two proto-Venus planets then collided, forming the planet Venus that exists today. The geological history of Venus could support this as no rocks older than 2 Ga have been found. There is still no general consensus as to what mechanisms caused increases in temperature. Numerous disciplines are working to solve the faint young Sun paradox including those from astrophysics, geology and planetary sciences. Without a doubt it plays a crucial environmental factor in the survival of life, and adds to the long list of almost inconceivable processes that eventually allowed our species to exist. With new evidence, one day we will hopefully arrive to a holistic conclusion to this bizarre paradox.
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COMIC STRIP
Synapse Comic Strip Grace Mullally
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HeLa cells are commonly used in biological research. They come from cervical cancer cells taken from a patient in 1951, who they have now outlived by over 60 years! Their active telomerase enzymes and oncogenic mutations make them immortal so they replicate rapidly and indefinitely. This makes them perfect for studying human cells in vitro. It is estimated that the number of HeLa cells that have replicated is now far greater than the number of cells in the original patient’s body!
Did you know? Andy Jones
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