Transcript

From Molecules to Life: A Physicist’s Search for Biology’s Secrets | Petra Schwille | TEDxTUM

URL: https://www.youtube.com/watch?v=ffqsyrRgtsY
Video ID: ffqsyrRgtsY
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[Music] yeah so since I can back can think back I um have been really fascinated by life in all its forms like many of us as a little kid I was intrigued by the little fuzzy and furry animals oh I need to push that button and um a little later I was not only content with the FY and furry ones but learned about the wildest and and weirdest creatures that you could find and then still a little later I uh read all I could read of pathogens and germs and parasites that infect and threaten our lives and I was really scared by this and as a teenager um I had a lot of time at that time we did not have um internet and we didn't have mobile phones so whenever I had time I thought what it was actually about that bizarre thing that created the human brain and with the human brain the ability to create Symphonies and Rockets it's pretty amazing if you look at it that we even can think about ourselves and that's something that is intrinsic to Life as a phenomenon so I I really wanted to know what is the definition of life and if you look in textbooks there not really a very nice and you know satisfying definition it's usually a selection of criteria you have metabolism you have um replication information but the what I found most intriguing about life is that although every single creature has only a a short time to exist the whole thing seems to be a NeverEnding and ever progressing story and even the smallest and simplest life form has the ability to learn and solve problems so we humans take a lot of pride in our ability to solve problems but if you look closely every even the smallest organism has this ability and it was Darwin who basically framed an expression for it Evolution almost 200 years ago and we still don't fully understand Evolution because it must have started with the constitutive Elements of Life with molecules because molecules were at the beginning of it but when and how did molecules have the ability or come up with the ability to learn and solve problems I couldn't imagine a more interesting question than that one but then I did not end up studying biology because in school I found biology really really Dreadful so many facts to learn the citric AIC cycle and the endoplasmic reticulum and I'm much more preferred physics there was also a lot of fact that I didn't care about accelerators and engines but what I liked about physics was that physic education made it pretty clear that if you want to understand anything from scratch you have to start doing the math and I was pretty good at math well I studied physics and I found that I got more math than I asked for but what I really liked about my physics education was experimental physics and particularly Optics Optics is a a fantastic branch of physics because it's so visual and you have these lasers and the Optics the the optical table and the lenses and the mirrors and you can basically build Optical systems all by yourself you don't have these huge teams and huge machines like in other branches of physics and what is also pretty cool about Optics is that you can with Optical instruments study living objects really the first microscope was in invented to study biological specimen almost 500 years ago and that's how it looked like it was actually pretty good already you could see the small structures of cork and even little um microorganisms during my PhD I I stayed with Optics and I um developed a method that was able to detect single molecules and um by a fluorescent label so we could study not only where they were in a in in a in a system but we could basically study the Dynamics so I developed a technique that allowed us to very quantitatively analyze how molecules are interacting with each other and if you will that's the basics of all life the interaction of molecules so we measured interactions of proteins with proteins of proteins with DNA and other molecules and we measured very precisely and understood these systems relatively well but we measured in aquous solution and of course our biological Partners they told us well okay you understand something about molecules but that's not life you have to measure in cells if you really want to understand life okay that's clear so we moved to cells cells are transparent so in principle you can apply your Optical techniques also to cells but what appeared to be first a technical problem you have to get rid of the background noise and all that very quickly turned into a very obnoxious problem because the system that we wanted to study that we could study very nicely in solution in the cell was very hard to Target every day we measured something else so it took us really four years of preparing a specific cellular system in a sea fish organism so that we in the end could make sense of what we measured somehow right the the arrow bars of our curves were still such that it made every quantitative research a cry but our biological Partners they were quite happy with what we measured and made some sense of it but at that time I have actually witnessed the my biology it's fascinating but it's also super complex because a cell is not just two molecules it's not 10 molecules it's not thousand molecules it's an incredible number of different molecules and an incredible number of interactions if you will you can compare it to the complexity of interactions in the internet right good luck with understanding that and even good luck luck with you know looking at a single system and trying to control all the rest it's not going to work because it is so complicated and at that time I I decided okay so seora fish is definitely not my organism so I would like to have a system that is really simple but still alive yeah good luck there is not such a no such system because a cell is composed of thousands and thousands of different components and if you want to understand its Essence in principle you have to com to reduce the complexity but to try and reduce the complexity from the top for example by taking elements out of the cells this is possible by gen genetic modification you will not be able to really beat the intrinsic complexity significantly so in fact if you really want to start understanding A system that you can control from scratch in principle you have to build it and that's a quote of a very famous physicist Richard fenman I guess some of you have heard of the name he basically a completely different context says if you want to if I have to what I do not create I do not understand so in principle if you really want to understand a system such as life you have to create it of course now we are a a little bit in a shaky water here is it is it allowed to create life we all have this idea of Frankenstein and it's probably not what you should do but in a way we're looking at molecules that are coming together to do something that to make the transition in principle from chemistry topology and that's far far away from any Frankenstein but how can you do it we're coming back to our phrased problem from the beginning life is opposed to solve problems so what do we have to do to bring molecules together such that these molecules are solving problems which problems are they supposed to solve in the first place well to put it uh basically very bluntly the first thing that these molecules need to do is somehow self-organize there's a very very important and very famous book by uh physicist another physicist uh shinger who went into Exile in Ireland during the second world war and there he had to uh lecture and he did not lecture about his shinger equation he lectured about what is life was not his home turf but it was very interesting what he what he said about life some of what he said was quite wrong but something was really really cool and that is that life is able to create order out of disorder we all know about entropy everybody everything wants to go to hell right everything wants to mess up every I mean we know that if you look at your desk uh at home you have the feeling entrop is acting all the time and life is able to undo that to sort molecules to make structures and patterns and even greater structures and patterns and these develop into something like an organism that is very very well controlled that beats entropy all the time and this is possible by the input of energy today we have just had our energy right the earliest organisms probably use sunlight we don't know so we need something that is able to create energy to self-organize and we also need some sort of a box around it compartment right so every living system is compartmentalized it has you know a very nice shell and this shell should not be ideally should not be a box that with solid walls it should be a boundary that is able to transform because life wants to continue and replicate so you need something that is keeping you know the self intact is able to basically keep things in and out and at the same time should be easy to transform and nature has found an amazing solution to this with phospholipid membranes the shell of all your cells of all cells that you can find on the on Earth they all have phospholipid membranes these are very thin layers of molecules that have a water loving head group and oily uh t and they basically form little double layers with the water leing head groups outside and the oily um Tails inside and they are keeping everything every biological molecule inside that needs to be in and keep everything out that needs to be out and they're very transformative so in my research and that's now the last bit of my uh talk I will show you a little bit of a glimpse of what we've already accomplished because we need molecules that are self-organizing but we also want molecules that are doing something self organizing is fine but they have this shell and if they really want to live they have to replicate they have to divide the shell so we are at the moment able to create a system of molecules that are self-organizing within a transformable shell and start changing this the the shape of of this shell towards not quite there yet but towards the self Division and I show you now a little movie where you can see it and I'm not sure how much time we still have um maybe you can see it twice or um uh it's not easy to see here so um what you can see over time is that structures are forming these are filaments made out of protein molecules and these protein molecules these filaments are basically able to transform the shape of our compartment but they need to be arranged into the middle of the compartment because they need to divided in two and what you can see here very nicely over time is how these molecules first form the filaments but also how they are basically by an oscillation reaction made possible by other species of molecules that are basically driving these filaments into the middle of the compartment and what you can see here very beautifully I think is that they start constricting this volume we are not there yet the force to constrict this volume is not yet great enough but we're very optimistic that we have the next factor in our hand to make that possible and what you see here is a system that consists of a membrane and five proteins still five not two but it's pretty cool I think and of course that is very far away from anything that lives but it's the first step and now I give you a homework you don't have to do it but we can basically talk about it in the Speakers Corner afterwards I want you to think about once we have accomplished this Division and I think we're pretty close to it what should we do next what is the next important thing that you would like to see from a living or a system that is supposed to be living at some point many things possible maybe you just think about it and let me know what I think it's very hard to say when we will be actually convinced that what we have in our uh in our hands under our microscope will be alive my personal convic conviction is that well probably only if that thing really surprises us somehow thank you [Music] [Applause]