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Interviewer: Shamini Bundell
Welcome to this week’s Nature Podcast. This week we’re looking at the role of ‘zombie cells’ in ageing, plus the perils of doing a PhD.
Interviewer: Benjamin Thompson
On top of that, some fingerprints from Antarctica’s past are causing concern for its future. This is the Nature Podcast for October the 26th2017. I’m Benjamin Thompson.
Interviewer: Shamini Bundell
And I’m Shamini Bundell.
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Interviewer: Shamini Bundell
First up, we’re joined by Adam Levy who’s been looking at signs of ice loss in Antarctica’s distant past.
Interviewer: Adam Levy
Sea level rise will be one of the most devastating consequences of climate change. But just how much the oceans will rise remains deeply uncertain and much of this uncertainty is down to Antarctica. In March last year we discussed two efforts to predict Antarctica’s future using computer models. One approach looked at processes of ice loss we’ve already seen unfold as the atmosphere and ocean have warmed and ice sheets flow into the sea. This model then projected these processes into the future. But as the world warms certain never before seen rapid-ice loss processes may come into play. The other model we discussed included speculative processes like these, leading to dramatic predictions: up to a metre of sea level rise by 2100 from Antarctica alone. But if these processes have never been seen before, how can we know if they’re going to happen in the future? Well it’s possible that they have happened in the distant past when the world was warmer than it is today. And now a study has gone looking for ancient evidence of one such process. This study is searching for the fingerprints of a process called marine ice-cliff instability. The lead author of the study, Matthew Wise, joined me in the studio.
Interviewee: Matthew Wise
So, marine ice-cliff instability is a relatively new theory and it takes the assumption that ice will get to a certain thickness which is generally about one kilometre and at this ice cliff only the part below sea level will actually be buttressed by the forces exerted on it by the sea itself. So for this remaining portion above sea level, any forces that are acting in the ice-cliff will be unopposed and as a result will simply cause a collapse once they’re above this critical thickness.
Interviewer: Adam Levy
Is this something we know to be the case?
Interviewee: Matthew Wise
For ice-cliffs themselves we don’t see anywhere on the planet today ice-cliffs that are anywhere near this critical thickness.
Interviewer: Adam Levy
This is a process then that we just haven’t directly see happen. Because the ice gets thicker as you go into the heart of Antarctica, there’s this fear that as more ice is lost from the edges, this critical thickness of the ice-cliff will eventually be reached so you and your team went looking for evidence to see whether this marine ice-cliff instability has indeed happened but in the more distant past.
Interviewee: Matthew Wise
We started looking for these features that we call iceberg plough marks and they are simply the scratches that are left in the sea floor when an iceberg that’s floating and drifting touches the sea floor and because it’s still drifting, will scrape through the sediments in a very similar way to how a farmer will plough through the field and these leave behind a mark that basically acts as a proxy for the shape of the iceberg that produced them.
Interviewer: Adam Levy
So how does that link to whether or not marine ice-cliff instability is a thing?
Interviewee: Matthew Wise
In our study we compared the shape and the size of the marks we see on the sea floor to what we would expect from icebergs that carve from Pine Island Glacier today. So, just as an example: in September 2017, a large iceberg called B44, carved from Pine Island Glacier which had an area of approximately 267 kilometres squared which is about four times the size of Manhattan Island. If we were to consider what the underside of this iceberg could look like we think it will be highly ragged and if these were to ground on the sea floor, we’d expect it to produce marks that were extremely parallel, possibly several kilometres in width whereas the marks we see in our study are relatively small in size, v-shaped in cross-section and could only have been produced by an iceberg that had one single sharp extension extending from its underside.
Interviewer: Adam Levy
How confident can we be that the signatures that you’re seeing are really caused by this particular process and not something else?
Interviewee: Matthew Wise
There are no areas in Antarctica or even anywhere in the world that we start to see plough marks of this shape and size and also this clarity at depths of 800, 850 metres. We start to put together that these plough marks would imply icebergs of the exact thickness that would cause this process to happen.
Interviewer: Adam Levy
Matthew Wise there. So these plough marks seem to suggest that marine ice-cliff instability has indeed happened in the distant past.
Interviewee: Jonathan Bamber
It is really interesting that there is potentially a kind of paleo evidence for the process existing. That really is striking.
Interviewer: Adam Levy
This is Jonathan Bamber, a glaciologist at the University of Bristol. He wasn’t involved in this study or in previous models that included marine ice-cliff instability and although interpretations of these types of marks aren’t Jonathan’s area of expertise, he feels that the study could help us understand what lies in store for Antarctica.
Interviewee: Jonathan Bamber
If these authors’ interpretations of the geostatistical evidence is correct then it does suggest that this process was important in the retreat of this glacier sometime in the past and I think that is an important result because it suggests that the process isn’t just hypothetical, it’s real, and it has occurred during a period of rapid retreat of this part of West Antarctica. This strengthens the case for including the process in modeling studies, for sure.
Interviewer: Adam Levy
So now that we have this evidence that marine ice-cliff instability may have taken place in the past, it makes more sense to take it into account to work out Antarctica’s future. And if this process does return to the Antarctic in coming decades, Matthew fears it could have troubling consequences for the future of our planet.
Interviewee: Matthew Wise
So if it were to start happening again, there’s the potential that it might almost be a runaway process that would have it continuously happening right into the hinterland of West Antarctica. It’s quite alarming and it’s made worse by the fact that a lot of the areas where we think this process could happen are already almost critically at risk.
Interviewer: Shamini Bundell
That was Matthew Wise and Jonathan Bamber talking with reporter Adam Levy. Read Matthew's paper at nature.com/nature. And make sure to give our previous podcast piece on modeling Antarctic ice loss a listen. It's from the 31st March 2016 episode. Still to come in the Research Highlights: a material with picky properties, and Germany’s creepy crawly concern. But now, over to you Benjamin to talk us through a new survey of PhD students…
Interviewer: Benjamin Thompson
So a couple of weekends back I had my first PhD dream in years. I was standing in the lab looking down at my list of experiments and they just kept getting longer and longer and longer. And then I woke up with the full cold sweat going on and it took me a second to realise it’s actually been 7 years since I graduated. But what if you’re still in the middle of your PhD? What is it really like to be a student in 2017? This week Natureis publishing the results from its fourth PhD survey looking at what inspires, excites and frustrates students. This year over 5700 students took part from astronomers all the way through to zoologists but let’s start with the important question. Are PhD students happy with their studies?
Interviewee: Chris Woolston
About 80% of people say that they’re satisfied with their PhD programme.
Interviewer: Benjamin Thompson
This is Chris Woolston, a freelance writer who’s been diving into the results for Nature.
Interviewee: Chris Woolston
Most people are glad they did it; they don’t have a lot of second thoughts and that came out in this as well, that about three quarters were happy with their decision to do a PhD which is impressive considering it’s such a big commitment.
Interviewer: Benjamin Thompson
The Naturesurvey asked students what kind of things they appreciated most about their PhD. And some of the top results included things like the intellectual challenge or creativity. And the hard work involved doesn’t seem to have put them off. 80% of them said that their desire to go into research was the same or higher than when they started their studies.
Interviewee: Chris Woolston
And that’s something that we have found previously too. In fact, this was a stronger trend a couple of years ago, that people who are in their PhD programmes haven’t lost their desire to do research.
Interviewer: Benjamin Thompson
Indeed, the majority of respondents wanted to move into academia upon graduating and most thought they’d find a permanent job within six years. Sadly the lack of faculty positions means that many are likely to be disappointed.
Interviewee: Chris Woolston
There’s a bit of an overload of PhD students compared to positions in academia but there’s still a strong desire among students to go into that field as opposed to industry and that was true two years ago and it’s true today even though there hasn’t been any improvement in that job market.
Interviewer: Benjamin Thompson
One of the survey’s respondents considering their job options is Kate Samardzic, a PhD student at the University of Technology in Sydney.
Interviewee: Kate Samardzic
It’s definitely something that’s on my mind and I guess that for a PhD student at a University especially, there’s this big question about whether I go into academia or into industry and it’s just kind of a bit of a balance to try to get all of these extra things done that might make you more employable if you were to go to industry but also generating data and having papers out that would make you employable if you wanted to go for a postdoc.
Interviewer: Benjamin Thompson
But mid-studies, thinking about a future career can get often put somewhere towards the bottom of PhD students’ to-do list.
Interviewee: Kate Samardzic
At my university we call it the PhD student’s dilemma. You’re trying to balance a lot of your teaching work, writing, hobbies, meeting with your supervisor, staying on top of the literature, planning experiments and then having a social life. It’s just a balancing act.
Interviewer: Benjamin Thompson
And this balancing act can be stressful. In this year’s survey participants were asked what they were most worried about since they started their PhD. The majority of those that responded said their career path but notably over a quarter highlighted mental health problems as something they were concerned about. Of that group about half said they’d actively sought help for anxiety or depression caused by their PhD.
Interviewee: Kate Samardzic
I’m really lucky. I have a close group of friends that I had in Undergrad who have all gone on to do PhDs as well so when we’re just talking amongst ourselves we do notice that we’re stressed and some of us have been to counselors and psychologists and a lot of it is related to the experience of being a PhD student.
Interviewer: Benjamin Thompson
Now, everybody knows that PhDs can be stressful but Kate decided to go further, co-founding Research Resilience, a support network for fellow students.
Interviewee: Kate Samardzic
My friends and I noticed that we started to feel better after venting to each other and we thought well wouldn’t it be better if more PhD students had this opportunity. So that’s where Research Resilience came into it and we realised we could create this safe place that acts as a forum slash seminar series, slash bit of a social club, a support group. And then students just get a chance to talk to each other and mingle over the PhD experience and it just gives people a sense that they are not alone in feeling these feelings.
Interviewer: Benjamin Thompson
In the survey over a third of students who sought help for anxiety or depression said their institution was helpful although nearly a fifth felt unsupported. This shows there is clearly room for improvement, particularly given that a paper this year in the journal Research Policysuggested that PhD students were at a higher risk of common psychiatric disorders than other highly educated people. I asked Kate what advice she might have for someone who’s not sure where to turn for help.
Interviewee: Kate Samardzic
First of all, talk to your peers; talk to as many PhD students as you can and I feel like you will find commonalities – that these experiences aren’t unique – and that’s actually a common part of it. And then obviously I would suggest either talking to your supervisor about it to try to identify what factors of the PhD are causing the students to feel this way and then of course I’d encourage seeking professional help if it is to that extent where things are difficult to cope with.
Interviewer: Benjamin Thompson
The thousands who filled in this year’s Naturesurvey have helped shine a light on what it is to be a PhD student in 2017. Thankfully though, although many are concerned about their situation and what kind of future lies ahead for them, the majority seem happy that they’ve made the right decision.
Interviewee: Kate Samardzic
I love my PhD. It’s so exciting and it’s exhilarating and I really enjoy the quest for knowledge that a PhD entails. I love finishing an experiment, getting a result, looking at it and then knowing I have to plan out another experiment to make it make sense and then going down this long rabbit hole and eventually finding an answer, or hoping I do. It’s still too early to say.
Interviewer: Benjamin Thompson
That was Kate Samardzic.You also heard me speaking to Chris Woolston. You can read his feature on the survey at Nature.com/news and you’ll be able to hear more about the results in the November edition of the NatureJobs Podcast. Look out for that wherever you get your pods.
Interviewer: Shamini Bundell
Still to come – the mysterious cells wrapped up in ageing. Plus, at the end of the show, we’ll be discussing the news – or lack of news – regarding the appointment of the White House science advisor. But now it’s back to Adam Levy for this week’s Research Highlights.
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Interviewer: Adam Levy
We can already do so much with the flick of a switch… power up a super computer, launch a rocket. Well now an electric field can help separate two gases that are so similar that it’s even hard to tell their names apart: propane and propene. Metal organic frameworks, or MOFs are scaffolds of metals linked by organic molecules. They can filter many different gases but the scaffold can bend, making sieving very similar sized molecules a bit of a strain. But electrifying a zinc based MOF made it more rigid and more picky. The mollified membrane plucked propane from propene – gases that differ by just two hydrogen atoms. Flicking the switch off permitted propane to pass through again. This technique could make MOFs useful for drug delivery. Sift through that paper in Science.
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Interviewer: Adam Levy
Germany has a soaring pest problem. Its airborne insects are vanishing into thin air. A team has been scooping bugs from the skies in nature reserves across Germany for nearly three decades. Flying bug biomass has been falling each year and the country has lost three quarters of its aerial insects since the study began. The biggest declines were during summer months. But the researchers don’t think that changes in weather or land use can fully explain why insect numbers are dropping like flies. Swat up on that research over at PLoS One.
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Interviewer: Shamini Bundell
Humans have been trying to understand the causes of ageing for millennia. In the 5th Century BC, one theory was that the body was like a lamp, and that ageing represented the body running out of life-fuel. Of course, modern research focuses on the cellular and molecular processes which contribute to old age and its associated diseases. And in recent years there’s been a growing amount of interest into so called ‘senescent cells’. Reporter Anand Jagatia takes a look at cell senescence, and whether studying it could help us understand - and maybe even reversethe ill-effects of ageing….
Interviewer: Anand Jagatia
Senescent cells have a pretty cool nickname: zombie cells. And they are kind of undead in that they stop replicating and dividing but they are also very hard to kill because they are resistant to cell death. They also secrete a complex variety of molecules that can have very profound effects on neighboring cells. So why do senescent cells enter this zombie-like state?
Interviewee: Judy Campisi
It’s extremely important for preventing cancer. So, undoubtedly the ability to stop dividing forever protects us from developing tumors.
Interviewer: Anand Jagatia
This is Judy Campisi, a cell molecular biologist from the Buck Institute for Research on Ageing, in the US.
Interviewee: Judy Campisi
But the other important function is during wound healing in the adult. Very often tissue industry is accompanied by the presence of senescent cells at the site of the injury. And if we eliminate those senescent cells recovery, wound healing and repair of the tissue is retarded.
Interviewer: Anand Jagatia
So, senescent cells play a role in optimizing important cell processes, but when we get older the secretion produced by senescent cells can start to cause problems – something that Judy calls the dark side of senescence.
Interviewee: Judy Campisi
We think the dark side of senescence has to do with the fact that as the organism ages there are more and more senescent cells that accumulate in a tissue. Then the cells become maladapted. Now these secretions can do things that are not necessarily beneficial. They can attract the immune system which can be destructive and very ironically, those secretions can also fuel the development of tumours.
Interviewer: Anand Jagatia
So could removing these cells help us to forestall some of the effects of ageing such as cancers in later life? Jan van Deursen is a cancer biologist at the Mayo Clinic in the United States who stumbled across the answer to this question. His group was trying to create a cancer model in mice but instead of developing tumours, the animals went on to display a rather different trait. They aged much more quickly than normal and they had a life span that was five times shorter.
Interviewee: Jan van Deursen
They developed cataracts in both eyes; they had a hunchback which was basically caused by accelerated muscle fibre degeneration and all these tissues that showed these accelerated ageing features had vast amounts of senescent cells and when we inactivated a key protein in this senescence pathway in these mice then we prevented the accumulation of senescent cells and that ameliorated these ageing-associated phenotypes. So that was a clue that there was a link between the accumulation of senescent cells and the development of ageing features.
Interviewer: Anand Jagatia
Further experiments from Jan’s group have shown that removing senescent cells in naturally ageing mice, prevented age associated declines in heart and kidney function and increased life spans by around 25% which is great news for any geriatric mice listening. But what about humans?
Interviewee: Jan van Deursen
Interviewer: Anand Jagatia
The first trials testing senolytics in humans are beginning to get under way. Unity Biotechnology, a company founded by Jan van Deursen, is hoping to trial these drugs over the next few years against ailments like osteoarthritis and pulmonary diseases. Jan tells me it’s an incredibly exciting time for the field but there are still lots of challenges ahead. For one thing there’s lots to learn about the basic properties of senescent cells and the drivers that cause senescence in the first place. With this in mind, I asked Judy Campisi the million dollar question: how close are we to using these findings to treat some of the diseases of ageing.
Interviewee: Judy Campisi
Oh I think we’re close. I can’t give you a number. You might as well ask me what the stock market’s going to do in the next week. If I give you an answer and you believe me… but the idea that it would be possible to extend health span – that older people were more vigorous and still productive for example. I think that’s going to happen soon – within the next decade or two… something like that.
Interviewer: Shamini Bundell
That was Judy Campisi from the Buck Institute for Research on Ageing and Jan van Deursen from the Mayo Clinic, talking to Anand Jagatia. There’s a feature on senescent cells in the latest of issue of Nature. Go to nature.com/news and for more on ageing you can listen to our May episode of Grand Challenges for a round table discussion on the topic.
Interviewer: Benjamin Thompson
Time now for this week’s News Chat and I’m joined us on the line by Lauren Morello, Nature’s America Bureau Chief.
Interviewee: Lauren Morello
Hello.
Interviewer: Benjamin Thompson
Lauren, thanks for joining us. First up, this week marks a rather unenviable record for the Trump administration. Maybe you could tell us what it is?
Interviewee: Lauren Morello
So, as of October 23rd, Donald Trump has now gone longer without a science advisor in place than any first term US President in the modern era, by any measure: whether you’re looking at the date a president announced who they want to be their science advisor; the date they submitted a formal nomination to the senate or the date that the senate approved that person.
Interviewer: Benjamin Thompson
So that begs the question then – what’s taking so long this time?
Interviewee: Lauren Morello
You know there are rumors that kind of swirl periodically about people that Trump is supposedly evaluating for the position and at least two or three times there’s been rumor that it’s going to happen soon but I think at this point it’s fair to say the delay is kind of an indication of where science sits in the Trump administration. You know, we’ve seen other indications of this: he nominated a climate sceptic who is not actually a scientist for the science advisor role at the US department of Agriculture. His administration is floating proposals that would essentially ban mainstream working scientists from advisory boards at the Environmental Protection Agency. The idea that they’re floating right now is that if you have received grant money from the EPA you can’t be an EPA advisor which contravenes decades of practice so you know I think this is part and parcel. I would say Trump is not completely anti-science which is the charge that gets thrown around. He seems to like biomedical science the way that a lot of Republicans historically have. But on the whole, he’s definitely not pulling an Obama and really highlighting the role of science in his administration.
Interviewer: Benjamin Thompson
Given that sometimes the President is known for shooting from the hip, it’s perfectly foreseeable that he could appoint someone today. Do we know anyone who may be in the running?
Interviewee: Lauren Morello
You know that’s always hard to say with Trump. There have been names floated for various positions that were touted as blocked – they turned out to not actually to get the job. Some of the names that were swirling around this spring included a scientist named William Happer from Princeton University who’s a pretty prominent climate sceptic and another guy name David Gelernter who is at Yale and he is a computer scientist. They both have fairly unorthodox views about science.
Interviewer: Benjamin Thompson
I mean maybe it’s important to let our listeners know what this job entails. And what are the risks in a continued delay?
Interviewee: Lauren Morello
The job has varied a little bit over time. Since the mid-1970s this person has been head of the White House Office of Science and Technology policy, which is pretty much a main body that provides advice on scientific and technical issues to the President, but in that job the person also plays an important role coordinating science across federal science agencies especially on issues that cut across more than one agency like climate change or even faith policy so when you don’t have someone in that office on a permanent, senate, confirmed basis, you are losing some of that ability to herd cats.
Interviewer: Benjamin Thompson
Well then Lauren perhaps it’s time to move on to slightly happier news. This week we’ve also got a report on a promising new treatment for the parasitic disease, sleeping sickness, which is also known as Human African Trypanosomiasis. And as I understand it rather disproportionately affects people in Sub-Saharan Africa and the current treatment for it is… it doesn’t seem a lot of fun.
Interviewee: Lauren Morello
No, it’s a series of infusions that have to be given over 10 days and that’s really problematic because in some of the places where this disease in endemic it’s not always safe to go out and go to the doctor to get this treatment or it requires a lot of effort to get there.
Interviewer: Benjamin Thompson
So this new drug is called fexinidazole which seems to be a lot better. So what do we know about that?
Interviewee: Lauren Morello
Fexinidazole is actually slightly less effective in some ways in clinical trials than the current standard of care but it has an advantage in how easy it is to administer. It’s much easier to give someone a pill so even though the pill is slightly less effective if you’re just looking at clinical trials, in the real world it’s probably going to be more effective because it’s easier to administer and it’s going to reach a lot more people.
Interviewer: Benjamin Thompson
And speaking of clinical trials then, how far through are we and what needs to be done to get this into the hands of people who need this the most?
Interviewee: Lauren Morello
So they finished the final clinical trials and presented the results from those at a meeting in Belgium earlier this month. I believe the European Medicines Agency is looking at that data or soon will. That application is on the way there at the very least and then if the EMA approve the drug that could pave the way for regulators in the Democratic Republic of Congo to also approve it and that’s one of the countries where sleeping sickness really strikes hard.
Interviewer: Benjamin Thompson
What struck me Lauren with fexinidazole is that it was actually initially developed for something else but has kind of been rediscovered.
Interviewee: Lauren Morello
Yeah, so this drug has actually been developed for another purpose in a non-profit group called the Drugs for Neglected Diseases Initiative. They came across this drug that has been developed and shelved by a big commercial firm, Sanofi. So this non-profit group decided to try out the drug in clinical trials for sleeping sickness with the Sanofi‘s permission and now they’re at the point where it looks like it was a really good idea to do so.
Interviewer: Benjamin Thompson
What sort of difference then do you think this will make for the people that live in DRC for example?
Interviewee: Lauren Morello
You know it’s hard to say until the drug is approved and on the ground but I think the the people who developed this drug and people who study this condition or provide aid in areas where this condition is common are just really excited by the idea of having a medicine to treat a really devastating disease in an easier way – just opening up treatment, making it more accessible, reducing the number of people whose lives are changed for the worse by sleeping sickness.
Interviewer: Benjamin Thompson
Nice to have some good news. Thanks Lauren. For more on those stories, head over to nature.com/news.
Interviewer: Shamini Bundell
That’s all for this week. But make sure to check our video channel for a recent documentary looking at two projects that are helping people with a terminal neurodegenerative disease to record video messages for their families. That’s at youtube.com/naturevideochannel. I’m Shamini Bundell
Interviewer: Benjamin Thompson
And I’m Benjamin Thompson.
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