Scouse Science Allíance – Page 2 – The Brain Bank North West

Bringing species back from the dead – a mammoth responsibility: Opinion Piece

July 31, 2014 by The Brain Bank North West

In this post I will take a look at the moral and ethical dilemmas posed by de-extinction. I’ll address the issue from numerous angles; though I must admit that a post such as this cannot do more than scratch the surface of such a complex issue. What I hope it will do is spark some debate and encourage you to think about where you stand on the matter. This is an incredibly important field of research and one that warrants debate and discussion. As such, I’d invite you to leave a comment at the bottom of the page if you want to weigh in. So, here we go…

Morality

A key argument used to defend the theory of de-extinction is that it will allow humanity to atone for past mistakes. Most, if not all, of the species scientists are proposing to bring back went extinct because of human activities. If we can develop the ability to undo the damage we’ve caused then do we not have a moral obligation to do so?

A light-coloured Cane Toad. Photo Credit: Bill Waller, via Wikipedia — A light-coloured Cane Toad.
Photo Credit: Bill Waller, via Wikipedia

Well, not necessarily! Just because we have the ability to do something doesn’t necessarily mean that we should. There have certainly been instances in which our ‘meddling’ with nature has had only positive results. For example, we wouldn’t have enough food had we not bred crops that grow at a faster rate and with greater yield. However, there have been many cases in which our attempts to improve our own lifestyle has dramatically backfired, as was the case when we tried to introduce the Cane Toad into Australia.

A Bearded Capuchin Monkey. Photo Credit: Bart van Dorp, via Wikipedia — A Bearded Capuchin Monkey.
Photo Credit: Bart van Dorp, via Wikipedia

Linked into this matter is the horrendously complex question of how morally right de-extinction is as a concept. Mankind is just another species on the planet, naturally selected to achieve dominance in many environments. Therefore, one might argue that any tools and technologies we have developed are the result of our natural intelligence. Other species have learned to use rudimentary tools without us gasping in horror; for example, bearded capuchin monkeys use rocks to open nuts. If you follow this thought process logically you come to the conclusion that ‘de-extinction’ is just another natural application of our intelligence. But, of course, your viewpoint on this depends entirely on whether you set humanity apart from other species.

Conservation

The other major argument in favour of de-extinction is the fact that the techniques developed in pursuit of that end-goal could be used to help prevent endangered species going extinct in the first place. The biggest challenge in cloning an extinct species is getting the body of a living organism to accept an embryo containingmostly the extinct species’ DNA. If scientists can achieve this, then one could assume that they could do so with species that are not extinct, but endangered. We would then have a way of artificially boosting numbers of endangered species.

The counterpoint to this argument is that such an ability might encourage apathy. Leaving aside the question of our moral right to try and stop species going extinct, would we go to such great lengths to preserve endangered species if we knew we could just bring them back at a later date? Many people would argue that we wouldn’t and that, in trying to be more responsible for the world around us, we might become even less so.

Environmental Impact

A model of a Woolly Mammoth at the Royal BC Museum in Victoria, Canada. Photo Credit: FunkMonk, via Wikipedia — A model of a Woolly Mammoth at the Royal BC Museum in Victoria, Canada.
Photo Credit: FunkMonk, via Wikipedia

Here we come to, in my opinion, the main crux of the argument. We have yet to consider how the revived species and the environment into which it is thrust will cope. For long-dead species, such as the woolly mammoth, the environment in which they lived will have changed drastically in their absence, adjusting to function without them. Regardless of whether they were wiped out by man, these species have lost their place in the world.

Let’s consider for a moment just a few of the ways in which the habitat of a species such as the woolly mammoth might have changed over time. Firstly, the climate may have changed. This could obviously mean that our de-extinct species can no longer survive in its old habitat. However, even if it could, if the average temperature or humidity has changed, then the range of other species that the environment supports could have changed drastically too. Animal species might have migrated or died off; plants might have died off or suddenly found themselves able to grow where they couldn’t before; and bacteria and viruses will doubtless have evolved massively over time too.

This leads onto the second major issue – the food web. If the inhabitants of the environment have changed in the absence of the extinct species, then it has no place in the modern-day food web. Quite frankly, even if the species living in an area haven’t changed, if enough time has passed then they will have evolved to survive without the extinct species, meaning it might still cause massive disruption. It might endanger the indigenous populations by outcompeting them or hunting them in a way they have not evolved to cope with, or it could be threatened with ‘re-extinction’ itself!

Finally, I mentioned earlier that bacteria and viruses would have evolved greatly over such a period of time. Well this offers no shortage of complications when trying to bring a species back from the dead. Obviously, a long-dead species’ immune system will be outdated, what with having missed out on potentially millennia of natural selection. We cannot know in advance but it might be that modern-day microbes could wipe out the resurrected species immediately if its immune system could not cope with these new threats.

Also, animals’bodies contain massive amounts of bacteria, which help our bodies to function. We could not digest our food as effectively as we do without bacterial colonisation. It is headache-inducing to try and work out the ways in which the body of a member of a resurrected species would respond to colonisation by all of these species that its ‘ancestors’ never encountered.

In short, it is very difficult to consider every single factor when introducing an organism into an environment in which it simply does not belong. There are often distant, subtle relationships and interactions between parts of an environment that we cannot anticipate.

Sergei Zimov surveying Pleistocene Park. Photo Credit: Enryū6473, via Wikipedia — Sergei Zimov surveying Pleistocene Park.
Photo Credit: Enryū6473, via Wikipedia

In more extreme cases, scientists may try to make an environment suit the extinct species, rather than going about things the other way round. For example, the Siberian steppe that served as the woolly mammoth’s habitat changed drastically at the end of the Pleistocene epoch (roughly 11,700 years ago). Russian scientist Sergei Zimov has, since the 1980s, been reintroducing flora and fauna into an arctic region of Siberia dubbed ‘Pleistocene Park’ in a bid to recreate the ecosystem that was lost millennia ago. This could, ultimately, include providing a home for mammoths.

Of course, here, we’re talking about manipulating entire environments rather than individual species. It is difficult to know where to draw the line, if one even believes that a line should be drawn anywhere! In my opinion, the line should be drawn before even taking de-extinction beyond being just a theory. I don’t believe that the potential benefits of such an ability outweigh the incredible and unknowable risks that come with playing God in this manner.

As I said before though, I would be very interested to know what you think of this and if you would like to add to my list of arguments. Here, we really have only just begun to consider the ramifications and justifications behind this incredibly controversial area of research.

This post, by author Ian Wilson, was kindly donated by the Scouse Science Alliance and the original text can be found here.

The Science of Star Trek: – The Trouble with Tribbles

July 28, 2014June 29, 2014 by The Brain Bank North West

This is the first in a series of posts exploring the science of Star Trek, courtesy of our friends at the Scouse Science Alliance. In this first post we delve into the real-life biology of everyone’s favorite purring ball of destruction – the Tribble!

These cute, fluffy, purring balls of joy are considered a mortal enemy of the Klingon Empire (Klingons are a warrior race who love a good battle, and in Kirk’s era they were often the bad guys). They notoriously multiplied uncontrollably on board the USS Enterprise under Captain Kirk in the episode ‘The Trouble with Tribbles’. Starfleet considers them dangerous organisms and forbids them from transport. Despite their purring nature towards humans, the same is not true of Klingons. In fact, Kirk used a Tribble to identify a Klingon in disguise. The Tribble reacted with a screeching noise. Now, how exactly do these fluffy little puffs manage to multiply at such extreme rates? Cleverly, each Tribble is ‘born pregnant’ and if given the smallest morsel of food, will give birth to 10 Tribbles, who in turn will also produce 10 Tribbles. Within hours you have hundreds of Tribbles, clogging up every console, air vent, and food replicator [2].

Is such a creature possible I hear you ask? Well, being a hermaphrodite is nothing new. Snails and plants are examples of this. They possess both male and female reproductive organs, although the female organs of one snail will normally mate with the male organs of another snail, i.e. sexual reproduction. However, in some hermaphrodites self-fertilization can occur [3]. Then there are those species that are able to effectively create clones of themselves via asexual reproduction, such as stick insects. The advantage of asexual reproduction is that it is a relatively quick way to populate an environment, and it does not rely on regular encounters with the opposite sex. It is considered most advantageous in favourable, stable environments. The down side is the inevitable lack of genetic diversity, which would be particularly problematic if conditions became unfavourable. Despite this, some stick insects have been shown to survive for a million years without sexual reproduction, suggesting that this method is genetically sustainable [4].

Therefore, it is very plausible that Tribbles are able to produce offspring in the absence of another Tribble. The only questionable aspect is the sheer speed at which they accomplish this. The shortest gestation period known currently for a mammal on earth is 12 days for the opossum. This animal is a marsupial and whilst it has a very short gestation period, its young are born almost foetal-like and therefore require nursing in the mother’s pouch for an extended period of time before reaching maturity [5]. With regards to Tribbles, not only would their gestation period have to take place in a matter of hours, but the ‘baby’ Tribblewould also have to reach maturity in an equally rapid manner.

If this could actually be achieved, then it would be a huge survival advantage. To be able to maximise breeding potential and minimise the energy intake required t parsons2 o do so, is the ambition of all species. What’s more, this rapid production of generations would only serve to increase mutation rates, which in some instances can help species adapt. In fact, much of this can be likened to microbes such as viruses and bacteria. Their rapid succession of generations allows them to adapt much more quickly than us, their human hosts. Therefore Tribbles are merely a victim of their own success. All they want is to eat and breed as efficiently as possible, who doesn’t? So in conclusion, Tribbles are quite like microbes, and microbes aren’t so bad. In fact, they can be quite cute and fluffy too!

This post, by author Bryony Parsons, was kindly donated by the Scouse Science Alliance and the original text can be found here.

References

http://www.edparsons.com/2006/03/google-earth-inspiration-was-star-treks-tricorder/
Okuda, M. and Okuda, D. 1997. The Star Trek Encyclopaedia, a reference guide to the future. Updated and expanded edition. POCKET BOOKS, USA. P 522.
Campbell, N. A. and Reece, J. B. Biology, sixth edition. Pearson Education, Inc, USA. P 975-978.
http://www.bbc.co.uk/nature/14122050
http://www.opossumsocietyus.org/opossum_reproduction_and_life_cycle.htm

In Defence of Parasites

May 26, 2014 by The Brain Bank North West

Parasites have a bad reputation. These tiny creatures are responsible for some of the most visually horrifying diseases known. For example, a microscopic worm causes the grotesquely swollen limbs of elephantiasis, while a single-celled parasite, Leishmania, is capable of destroying a victim’s face. However, we humans often concentrate on the worst aspects of certain species – just ask your average wasp or spider – and there is much more to parasites than disease. Many parasitic infections in fact cause little harm – if we die, so do they – and by concentrating solely on the diseases they cause we miss out on some fascinating underlying biology.

I remember arriving late for one of my first undergraduate parasitology lectures and being pleased to find the lecturer had not yet arrived either. “Sorry I’m late,” he said when he appeared, “I was on the Tibetan plateau yesterday, looking for tapeworms in foxes”. This lecture was my first glimpse into the ecology of parasites, and where the elegance and sheer complexity of their life cycles became apparent. We all marvel at the epic journeys in nature, such as the great wildebeest migration across the Serengeti. But compared to parasites, those TV regulars have it easy. Strolling from one part of Africa to another, avoiding the occasional crocodile or lion? Simple.

The life cycles of parasites can be incredibly complex and quite ingenious. These animals often need to jump between several host species to mature and reproduce and many have evolved amazing ways of completing these unlikely journeys.

Toxoplasma gondii is a single-celled parasite that can infect a number of mammals, but which ultimately needs to find its way into a cat to sexually reproduce. The most common intermediate hosts for Toxoplasma are rodents and the parasite has evolved the remarkable ability to alter the behaviour of these animals in order to maximise its chances of finding a feline. A mouse or rat that becomes infected with Toxoplasma not only loses its natural fear of cats but can even become actively drawn to their scent, deliberately seeking out catty environments and thereby increasing its chance of being eaten and the parasite’s chance of transmission.

The Lancet fluke, a flatworm that infects the liver of grazing animals, is also adept at brain washing its host. This worm has two intermediate hosts, a snail and an ant. Snails become infected by eating infected animal droppings, after which the parasites develop into cysts and are released in the snail’s slime. Passing ants then swallow these cysts as they graze on the slime as a source of moisture. This cycle alone is a beautiful example just how complex parasites’ life cycles can be, but the really clever part comes next…

Following infection of the ant, the Lancet fluke begins to exert its mind control. The ant’s behaviour becomes peculiar and, like Toxoplasma and its stupidly brave rodents, this behaviour is due to the parasite’s attempts to increase its chance of transmission. In the evening the ant leaves its colony members and travels to the top of some nearby vegetation. Once there, it clamps its jaws on tightly and stays until dawn, a ruse by the parasite to increase the likelihood of the ant being accidentally swallowed by grazing cattle. Clever stuff, but the parasite is cleverer still. When day breaks, the fluke senses the rise in temperature and relinquishes its control over its insect host, allowing it to continue with its usual anty chores. This prevents the ant dying in the daytime heat, which would also kill its parasitic puppeteer.

Even within a single host, parasites face extraordinary challenges. A single individual may have to navigate blindly from the gut to the lungs, from the skin to the eye, or from the liver to the brain. Tunnelling through organs and hitching a ride in our bloodstream, the travelling parasites must face a relentless barrage from our immune system. Many have therefore evolved sophisticated ways of dampening down host immune responses to protect themselves. They are in fact so proficient at this that many scientists believe the lack of parasitic infection in developed countries, and the loss of their calming influence on our immune system, has led to the observed increase in allergies and autoimmune diseases. Indeed, deliberate infection with parasitic worms has actually been used to successfully treat many such disorders.

The complexity and elegance of parasites is often overlooked, but they are marvels of nature. Parasites can treat as well as cause disease, and can alter host physiology and behaviour; they form important parts of ecosystems and undertake journeys which, though microscopic, are unrivalled in nature. A single individual must endure environments as diverse and hostile as the bottom of a pond, the gut of a snail and the tissues of a wildebeest. And yet who gets the David Attenborough treatment?

This post, by author Dr. Andy Turner, was kindly donated by the Scouse Science Alliance and the original text can be found here. SSA

The Promise of Poop: Faecal transplants to treat C. difficile infection – An age old therapy moving into the light?

April 28, 2014April 28, 2014 by The Brain Bank North West

Clostridium difficile – a hospital superbug?

Clostridium difficile is a bacterium that is commonly found in the environment around us – in soil, air and water. C. difficile is also present in the gut of up to 3% of healthy adults and 66% of infants, but rarely causes any problems in healthy people. This is because it is usually kept in line by the normal bacterial population in the intestine. However, when people undergo antibiotic treatment, this can disrupt the balance of bacteria in the gut, allowing C. difficile to rapidly multiply and cause illness. C. difficile infection (CDI) can result in very mild diarrhoea, but can also result in some particularly nasty, life threatening symptoms, that in the extreme can lead to someone having their colon surgically removed.

CDI is the leading cause of infectious diarrhoea in healthcare institutions worldwide, and the problem doesn’t seem to be going away anytime soon. In fact, over the last decade CDI has become more frequent, more difficult to get rid of fully and more often actually causes death. This is thought to be due to the emergence of more aggressive C. difficile strains.

CDI is commonly treated with antibiotic therapy, but this is by no means the perfect treatment option as it is becoming increasingly associated with treatment failure and return of infection. In addition, CDI weighs a heavy financial burden on healthcare systems across the world, each case costing approximately £4000. This particular conundrum has led to a race in the development of alternative treatment therapies for the disease and has recently reignited the interest in an age old therapy: the faecal transplant.

What is a faecal transplant?

The faecal transplant has been knocking around for centuries, with its first use to treat diarrhoea being described all the way back in 4th century China. Possibly one of the reasons it hasn’t proved so popular is due to the fact that it sounds so disgusting. The faecal transplant involves the transfer of poop from a healthy individual to the gut of a patient to cure their disease. Obviously, there is only one of two routes to administer this lovely load; via a nose tube directly into the stomach (apparently rather unpleasant when the patient burps) or through colonoscopy. I think we can all agree that neither of these options seems at all appealing, but treating patients with CDI with faecal transplants does seem to work.

Indeed, clinical trials suggest that the faecal transplants are both well tolerated and very effective. In the most recent study carried out in the Netherlands, published in the New England Journal of Medicine earlier this year, it was found that that faecal transplants cured 15 out of 16 patients with recurring CDI – a 96% success rate compared to less than 30% for standard antibiotic therapy.

So, what is the science behind a faecal transplant and why does it work?

It is estimated that over 4000 bacterial species reside in the gastrointestinal tract, and amazingly, we are inherently outnumbered by the number of bacteria that live in our body. The human microbiota contains as many as 100 trillion bacteria, which is ten times greater than the number of human cells in our body. Not to worry though folks, these bacteria are friends, not foes.

In fact, it has become very apparent in recent years that friendly bacteria residing in the gut do their bit to keep us healthy. A number of diseases, including cancer, inflammatory bowel disease and arthritis, are linked with changes in the make-up of the types of gut bacteria. With respect to C. difficile infection, the disease most commonly arises in patients who have undergone antibiotic therapy, which results in the disruption of their normal intestinal microbiota. Antibiotics can wipe out the good bacteria in the gut that usually provide a protective defence against C. difficile, allowing it to flourish and cause infection.

With this in mind, a faecal transplant doesn’t seem so daft. Transferring poop from a healthy donor to the gut of a patient with CDI is thought to restore the good bacteria for them to help fight C. difficile, preventing any further disease.

Can we get past the yuck factor?

We know that the results from clinical trials suggest that the faecal transplant not only works, but is well tolerated: the two gold stars with respect to disease therapy. But the fact remains that the faecal transplant is also, quite frankly, gross. People often don’t like the thought of taking others seconds or leftovers – is this treatment taking it one step too far?

Testimonials from patients treated with the faecal transplant suggest quite the opposite; these patients have won their battle with CDI and changed their life thanks to the unusual therapy. They are all more than happy to recommend it to others.

Yes, we know that the faecal transplant is not pretty, but neither is the possibility of major surgery leaving us with a stoma bag because all other treatment has failed.

Which option would you choose?

This post, by author Hannah Simpson, was kindly donated by the Scouse Science Alliance and the original text can be found here.