I'm an ocean microbiologist at the University of Tennessee, and I want to tell you guys about some microbes that are so strange and wonderful that they're challenging our assumptions about what life is like on Earth.
Ja sam okeanski mikrobiolog na Univerzitetu u Tenesiju, i želim da vam pričam o nekim mikrobima koji su toliko čudni i divni da izazivaju naše pretpostavke o tome kakav je život na Zemlji.
So I have a question. Please raise your hand if you've ever thought it would be cool to go to the bottom of the ocean in a submarine? Yes. Most of you, because the oceans are so cool.
Imam pitanje. Podignite ruku ako ste ikada pomislili da bi bilo super ići na dno okeana u podmornici. Da. Većina vas, jer su okeani tako super.
Alright, now -- please raise your hand if the reason you raised your hand to go to the bottom of the ocean is because it would get you a little bit closer to that exciting mud that's down there.
U redu, sada - podignite ruku ako je razlog zašto ste podigli ruku da idete na dno okeana taj što bi vas to dovelo malo bliže tom uzbudljivom mulju koji je tamo dole.
(Laughter)
(Smeh)
Nobody. I'm the only one in this room.
Niko. Jedino ja u ovoj prostoriji.
Well, I think about this all the time. I spend most of my waking hours trying to determine how deep we can go into the Earth and still find something, anything, that's alive, because we still don't know the answer to this very basic question about life on Earth.
Pa, ja o tome mislim sve vreme. Provodim veći deo svojih budnih sati pokušavajući da odredim koliko duboko možemo ići u Zemlju i i dalje naći nešto, bilo šta što je živo, jer još uvek ne znamo odgovor na ovo vrlo bazično pitanje o životu na Zemlji.
So in the 1980s, a scientist named John Parkes, in the UK, was similarly obsessed, and he came up with a crazy idea. He believed that there was a vast, deep, and living microbial biosphere underneath all the world's oceans that extends hundreds of meters into the seafloor, which is cool, but the only problem is that nobody believed him, and the reason that nobody believed him is that ocean sediments may be the most boring place on Earth.
Tako je u 1980-im naučnik po imenu Džon Parks, u UK-u, bio slično opsednut, i pala mu je na pamet luda ideja. Verovao je da postoji ogromna, duboka i živa mikrobiološka biosfera ispod svih svetskih okeana koja se prostire stotinama metara u morskom dnu, što je super, ali je jedini problem bio što mu niko nije verovao, a razlog što mu niko nije verovao je što su okeanski sedimenti možda najdosadnije mesto na Zemlji.
(Laughter)
(Smeh)
There's no sunlight, there's no oxygen, and perhaps worst of all, there's no fresh food deliveries for literally millions of years. You don't have to have a PhD in biology to know that that is a bad place to go looking for life.
Nema sunčeve svetlosti, nema kiseonika, i možda najgore od svega, nema isporuke sveže hrane bukvalno milionima godina. Ne morate biti doktor biologije da biste znali da je to loše mesto za traženje života.
(Laughter)
(Smeh)
But in 2002, [Steven D'Hondt] had convinced enough people that he was on to something that he actually got an expedition on this drillship, called the JOIDES Resolution. And he ran it along with Bo Barker Jørgensen of Denmark. And so they were finally able to get good pristine deep subsurface samples some really without contamination from surface microbes. This drill ship is capable of drilling thousands of meters underneath the ocean, and the mud comes up in sequential cores, one after the other -- long, long cores that look like this. This is being carried by scientists such as myself who go on these ships, and we process the cores on the ships and then we send them home to our home laboratories for further study.
Ali 2002. godine, Stiven D'Hont je ubedio dovoljno ljudi da je na tragu nečega da je zapravo dobio ekspediciju na ovu bušilicu, pod nazivom JOIDES Rezolucija. I sproveo ju je zajedno sa Boom Barkerom Jorgensenom iz Danske. Tada su konačno mogli da prikupe dobre čiste uzorke iz dubokog podzemlja, neke zaista bez kontaminacije od površinskih mikroba. Ova bušilica je sposobna za bušenje hiljadama metara ispod okeana, a mulj se pojavljuje u sekvencijalnim jezgrima, jedno za drugim - duga, duga jezgra koja izgledaju ovako. Ovo sprovode naučnici poput mene koji idu na ove brodove, obrađujemo jezgra na tim brodovima, a zatim ih šaljemo kući našim laboratorijama na dalje proučavanje.
So when John and his colleagues got these first precious deep-sea pristine samples, they put them under the microscope, and they saw images that looked pretty much like this, which is actually taken from a more recent expedition by my PhD student, Joy Buongiorno. You can see the hazy stuff in the background. That's mud. That's deep-sea ocean mud, and the bright green dots stained with the green fluorescent dye are real, living microbes.
Kada su Džon i njegove kolege dobili te prve dragocene duboko morske čiste uzorke, stavili su ih pod mikroskop, i videli slike koje su izgledale prilično poput ovoga, što je zapravo napravio na novijoj ekspediciji moj student doktorskih studija, Džoj Bonđorno. Možete videti nejasne stvari u pozadini. To je blato. To je duboko okeansko blato, a sjajne zelene tačke obojene fluorescentnom zelenom bojom su pravi, živi mikrobi.
Now I've got to tell you something really tragic about microbes. They all look the same under a microscope, I mean, to a first approximation. You can take the most fascinating organisms in the world, like a microbe that literally breathes uranium, and another one that makes rocket fuel, mix them up with some ocean mud, put them underneath a microscope, and they're just little dots. It's really annoying. So we can't use their looks to tell them apart. We have to use DNA, like a fingerprint, to say who is who.
Sada vam moram reći nešto zaista tragično o mikrobima. Svi izgledaju isto pod mikroskopom, mislim, do prve procene. Možete uzeti najfascinantnije organizme na svetu, poput mikroba koji bukvalno udiše uranijum i drugi koji pravi raketno gorivo, pomešajte ih sa malo okeanskog mulja, stavite ih pod mikroskop, i oni su samo tačkice. Zaista je iritirajuće. Prema tome ne možemo ih razlikovati po izgledu. Moramo koristiti DNK, poput otiska prsta, da bismo rekli ko je ko.
And I'll teach you guys how to do it right now. So I made up some data, and I'm going to show you some data that are not real. This is to illustrate what it would look like if a bunch of species were not related to each other at all. So you can see each species has a list of combinations of A, G, C and T, which are the four sub-units of DNA, sort of randomly jumbled, and nothing looks like anything else, and these species are totally unrelated to each other. But this is what real DNA looks like, from a gene that these species happen to share. Everything lines up nearly perfectly. The chances of getting so many of those vertical columns where every species has a C or every species has a T, by random chance, are infinitesimal. So we know that all those species had to have had a common ancestor. They're all relatives of each other.
I sada ću vas naučiti kako da to uradite. Izmislila sam neke podatke i pokazaću vam neke podatke koji nisu istiniti. Ovo služi da ilustruje kako bi izgledalo da mnoge vrste nisu nikako povezane jedna sa drugom. Možete videti da svaka vrsta ima niz kombinacija A, G, C i T, što su 4 podjedinice DNK, nasumično pomešane, i ništa ne liči ni na šta, i ove vrste apsolutno nisu povezane jedna sa drugom. Ali ovako izgleda prava DNK, iz gena koje ove vrste igrom slučaja dele. Sve se uklapa skoro savršeno. Šanse da se dobije toliko tih vertikalnih kolona gde svaka vrsta ima C ili svaka vrsta ima T, sasvim slučajno, su beskonačne. Znamo da su sve te vrste morale da imaju zajedničkog pretka. Svi su rođaci jedni drugima.
So now I'll tell you who they are. The top two are us and chimpanzees, which y'all already knew were related, because, I mean, obviously.
A sada ću vam reći ko su oni. Prve dve smo mi i šimpanze, već znate da smo u srodstvu, jer, mislim, očigledno je.
(Laughter)
(Smeh)
But we're also related to things that we don't look like, like pine trees and Giardia, which is that gastrointestinal disease you can get if you don't filter your water while you're hiking. We're also related to bacteria like E. coli and Clostridium difficile, which is a horrible, opportunistic pathogen that kills lots of people. But there's of course good microbes too, like Dehalococcoides ethenogenes, which cleans up our industrial waste for us. So if I take these DNA sequences, and then I use them, the similarities and differences between them, to make a family tree for all of us so you can see who is closely related, then this is what it looks like. So you can see clearly, at a glance, that things like us and Giardia and bunnies and pine trees are all, like, siblings, and then the bacteria are like our ancient cousins. But we're kin to every living thing on Earth. So in my job, on a daily basis, I get to produce scientific evidence against existential loneliness.
Ali smo takođe u srodstvu sa stvarima na koje ne ličimo, poput borova i giardioze, što je ono gastrointestinalno oboljenje koje možete dobiti ako ne filtrirate vodu dok planinarite. Takođe smo u srodstvu sa bakterijama poput E.coli i Clostridium difficile, što je grozni, oportunistički patogen koji ubija mnogo ljudi. Ali postoje naravno i dobri mikrobi, poput Dehalococcoides etenogena, koji čiste naš industrijski otpad. Ako uzmem ove DNK nizove, i iskoristim ih, sličnosti i razlike između njih, da napravim porodično stablo za sve nas da biste videli ko je u bližem srodstvu, onda to izgleda ovako. I možete jasno videti, letimice, da su stvari poput nas i giardioze i zečeva i borova svi, kao, braća i sestre, a da su bakterije kao naši prastari rođaci. Ali mi smo u srodstvu sa svakim živim bićem na Zemlji. Na svom poslu, svakodnevno, stvaram naučne dokaze protiv egzistencijalne usamnjenosti.
So when we got these first DNA sequences, from the first cruise, of pristine samples from the deep subsurface, we wanted to know where they were. So the first thing that we discovered is that they were not aliens, because we could get their DNA to line up with everything else on Earth. But now check out where they go on our tree of life. The first thing you'll notice is that there's a lot of them. It wasn't just one little species that managed to live in this horrible place. It's kind of a lot of things. And the second thing that you'll notice, hopefully, is that they're not like anything we've ever seen before. They are as different from each other as they are from anything that we've known before as we are from pine trees. So John Parkes was completely correct. He, and we, had discovered a completely new and highly diverse microbial ecosystem on Earth that no one even knew existed before the 1980s.
Kada smo dobili ove prve nizove DNK, sa prvog krstarenja, čistih uzoraka duboko ispod površine, želeli smo da znamo gde su bili. Prva stvar koju smo otkrili je da nisu bili vanzemaljci, jer smo njihovu DNK mogli da uskladimo sa svim drugim na Zemlji. Ali sada vidite gde su oni na našem stablu života. Prvo što ćete primetiti je da ih ima mnogo. Nije samo jedna mala vrsta uspela da preživi na ovom groznom mestu. Zapravo je to mnogo stvari. A druga stvar koju ćete primetiti, nadam se, je da one nisu nalik ničemu što smo ranije videli. Razlikuju se među sobom koliko i od bilo čega što smo ranije znali, koliko i mi od borova. Tako da je Džon Parks bio potpuno u pravu. On, i mi, smo otkrili potpuno novi i vrlo raznovrsni mikrobiološki ekosistem na Zemlji za koji niko nije ni znao da postoji pre 1980-ih.
So now we were on a roll. The next step was to grow these exotic species in a petri dish so that we could do real experiments on them like microbiologists are supposed to do. But no matter what we fed them, they refused to grow. Even now, 15 years and many expeditions later, no human has ever gotten a single one of these exotic deep subsurface microbes to grow in a petri dish. And it's not for lack of trying. That may sound disappointing, but I actually find it exhilarating, because it means there are so many tantalizing unknowns to work on. Like, my colleagues and I got what we thought was a really great idea. We were going to read their genes like a recipe book, find out what it was they wanted to eat and put it in their petri dishes, and then they would grow and be happy. But when we looked at their genes, it turns out that what they wanted to eat was the food we were already feeding them. So that was a total wash. There was something else that they wanted in their petri dishes that we were just not giving them.
Sada smo bili na dobrom putu. Sledeći korak je bio da gajimo ove egzotične vrste u petrijevoj šolji da bismo mogli da vršimo prave eksperimente što bi mikrobiolozi i trebalo da rade. Ali bez obzira na hranu, odbijali su da rastu. Čak i sada, 15 godina i mnogo ekspedicija kasnije, nijedan čovek nije naveo nijedan od ovih egzotičnih dubokih podzemnih mikroba da raste u petrijevoj šolji. I to ne zbog nepokušavanja. To može zvučati razočaravajuće, ali ja to smatram uzbudljivim, jer to znači da postoji toliko mučnih nepoznanica na kojima se može raditi. Moje kolege i ja smo dobili ono što smo mislili da je zaista dobra ideja. Hteli smo da čitamo njihove gene kao knjigu recepata, otkrijemo šta žele da jedu i stavimo to u njihove petrijeve šolje, i oni će rasti i biti srećni. Ali kada smo pogledali njihove gene ispostavilo se da je ono što su želeli da jedu bila hrana koju smo im već davali. To je bio totalni poraz. Postojalo je nešto drugo što su želeli u svojoj petrijevoj šolji što im nismo davali.
So by combining measurements from many different places around the world, my colleagues at the University of Southern California, Doug LaRowe and Jan Amend, were able to calculate that each one of these deep-sea microbial cells requires only one zeptowatt of power, and before you get your phones out, a zepto is 10 to the minus 21, because I know I would want to look that up. Humans, on the other hand, require about 100 watts of power. So 100 watts is basically if you take a pineapple and drop it from about waist height to the ground 881,632 times a day. If you did that and then linked it up to a turbine, that would create enough power to make me happen for a day. A zeptowatt, if you put it in similar terms, is if you take just one grain of salt and then you imagine a tiny, tiny, little ball that is one thousandth of the mass of that one grain of salt and then you drop it one nanometer, which is a hundred times smaller than the wavelength of visible light, once per day. That's all it takes to make these microbes live. That's less energy than we ever thought would be capable of supporting life, but somehow, amazingly, beautifully, it's enough.
Kombinovanjem merenja sa mnogo različitih mesta širom sveta, moje kolege sa Univerziteta Južne Kalifornije, Dag Larou i Jan Amend, su uspele da izračunaju da svaka od ovih dubinskih mikrobioloških ćelija zahteva samo jedan zeptovat snage, i pre nego što izvadite svoje telefone, zepto je 10 do -21, jer znam da bih ja volela da vidim šta to znači. Ljudi, s druge strane, zahtevaju oko 100 vati snage. 100 vati je zapravo ako uzmete ananas i ispustite ga sa visine pojasa na zemlju 881.632 puta na dan. Da ste to uradili, a zatim ga povezali za turbinu, to bi stvorilo dovoljno snage da preživim jedan dan. Zeptovat je, jednostavno rečeno, ako uzmete jedno zrno soli a zatim zamislite sitnu, sitnu, malu loptu koja je jedan hiljaditi deo mase tog zrna soli a zatim ga ispustite jedan nanometar, što je sto puta manje od dužine talasa vidljive svetlosti, jednom dnevno. To je sve što ove mikrobe drži živima. To je manje energije nego što smo ikada mislili da može održati život, ali je to nekako, zadivljujuće, predivno, dovoljno.
So if these deep-subsurface microbes have a very different relationship with energy than we previously thought, then it follows that they'll have to have a different relationship with time as well, because when you live on such tiny energy gradients, rapid growth is impossible. If these things wanted to colonize our throats and make us sick, they would get muscled out by fast-growing streptococcus before they could even initiate cell division. So that's why we never find them in our throats. Perhaps the fact that the deep subsurface is so boring is actually an asset to these microbes. They never get washed out by a storm. They never get overgrown by weeds. All they have to do is exist. Maybe that thing that we were missing in our petri dishes was not food at all. Maybe it wasn't a chemical. Maybe the thing that they really want, the nutrient that they want, is time. But time is the one thing that I'll never be able to give them. So even if I have a cell culture that I pass to my PhD students, who pass it to their PhD students, and so on, we'd have to do that for thousands of years in order to mimic the exact conditions of the deep subsurface, all without growing any contaminants. It's just not possible. But maybe in a way we already have grown them in our petri dishes. Maybe they looked at all that food we offered them and said, "Thanks, I'm going to speed up so much that I'm going to make a new cell next century. Ugh.
Ako ovi dubinski podzemni mikrobi imaju vrlo različit odnos sa energijom nego što smo prethodno mislili, onda sledi da će oni morati da imaju različit odnos i sa vremenom, jer kada živite na tako malim energetskim gradijentima, brzi rast je nemoguć. Da su ove stvari želele da kolonizuju naša grla i razbole nas, nadjačale bi ih brzorastuće streptokoke pre nego što bi i započele deobu ćelija. Zato ih nikada ne nalazimo u našim grlima. Možda je činjenica da je duboko ispod površine tako dosadno zapravo prednost za ove mikrobe. Nikada ih ne zbriše oluja. Nikada ne zarastu u korov. Sve što moraju da rade je da postoje. Možda ono što nam je nedostajalo u petrijevoj šolji uopšte nije bila hrana. Možda nije bila hemikalija. Možda je ono što oni zaista žele, hranljivi sastojak koji zaista žele, vreme. Ali vreme je jedino što ja nikada neću moći da im dam. Čak i da imam ćelijsku kulturu koju prenosim na svoje studente, koji prenose na svoje studente, itd, morali bismo to da radimo hiljadama godina kako bismo oponašali iste uslove duboko ispod površine, sve bez uzgajanja kontaminanata. Jednostavno nije moguće. Ali možda na način na koji smo ih već uzgajali u petrijevim šoljama. Možda su gledali u svu tu hranu koju smo im nudili i rekli: „Hvala, toliko ću ubrzati da ću napraviti novu ćeliju sledećeg veka. Ah“.
(Laughter)
(Smeh)
So why is it that the rest of biology moves so fast? Why does a cell die after a day and a human dies after only a hundred years? These seem like really arbitrarily short limits when you think about the total amount of time in the universe. But these are not arbitrary limits. They're dictated by one simple thing, and that thing is the Sun. Once life figured out how to harness the energy of the Sun through photosynthesis, we all had to speed up and get on day and night cycles. In that way, the Sun gave us both a reason to be fast and the fuel to do it. You can view most of life on Earth like a circulatory system, and the Sun is our beating heart.
Zbog čega se onda ostatak biologije kreće tako brzo? Zašto ćelija umire nakon jednog dana, a ljudsko biće umire nakon samo sto godina? Ovo izgleda kao stvarno proizvoljno kratka granica kada pomislite na ukupnu količinu vremena u univerzumu. Ali ovo nisu proizvoljne granice. Njih diktira jedna jednostavna stvar, a ta stvar je Sunce. Čim je život ukapirao kako da upotrebi sunčevu energiju kroz fotosintezu, svi smo morali da ubrzamo i uskočimo u cikluse dana i noći. Na taj način nam je Sunce dalo i razlog da budemo brzi i gorivo da to uradimo. Većinu života na Zemlji možete posmatrati kao cirkulatorni sistem, a Sunce je naše srce koje kuca.
But the deep subsurface is like a circulatory system that's completely disconnected from the Sun. It's instead being driven by long, slow geological rhythms. There's currently no theoretical limit on the lifespan of one single cell. As long as there is at least a tiny energy gradient to exploit, theoretically, a single cell could live for hundreds of thousands of years or more, simply by replacing broken parts over time. To ask a microbe that lives like that to grow in our petri dishes is to ask them to adapt to our frenetic, Sun-centric, fast way of living, and maybe they've got better things to do than that.
Ali duboko podzemlje je kao cirkulatorni sistem potpuno nepovezan sa Suncem. Umesto toga je vođen dugim, sporim geološkim ritmovima. Trenutno ne postoji teorijska granica životnog veka jedne ćelije. Sve dok postoji bar mali energetski gradijent koji se može iskoristiti, teoretski, ćelija bi mogla da živi stotinama hiljada godina i više, jednostavno vremenom zamenjujući pokvarene delove. Pitati mikrob koji tako živi da raste u našoj petrijevoj šolji, je pitati ih da se prilagode našem pomamnom, Sunčanom, brzom životu, a možda oni imaju pametnija posla.
(Laughter)
(Smeh)
Imagine if we could figure out how they managed to do this. What if it involves some cool, ultra-stable compounds that we could use to increase the shelf life in biomedical or industrial applications? Or maybe if we figure out the mechanism that they use to grow so extraordinarily slowly, we could mimic it in cancer cells and slow runaway cell division. I don't know. I mean, honestly, that is all speculation, but the only thing I know for certain is that there are a hundred billion billion billlion living microbial cells underlying all the world's oceans. That's 200 times more than the total biomass of humans on this planet. And those microbes have a fundamentally different relationship with time and energy than we do. What seems like a day to them might be a thousand years to us. They don't care about the Sun, and they don't care about growing fast, and they probably don't give a damn about my petri dishes ...
Zamislite da možemo dokučiti kako su uspeli da to urade. Šta ako to uključuje neke super, ultra stabilne smese koje možemo koristiti da povećamo rok trajanja u biomedicinske i industrijske svrhe? Ili ako shvatimo mehanizme pomoću kojih oni rastu tako izuzetno sporo, mogli bismo da prenesemo to na ćelije raka i usporimo deobu ćelija. Ne znam. Mislim, iskreno, ovo je sve spekulacija, ali jedino što zasigurno znam je da postoji sto milijardi milijardi milijardi živih mikrobioloških ćelija ispod svih svetskih okeana. To je 200 puta više nego ukupna biomasa svih ljudi na ovoj planeti. A ti mikrobi imaju fundamentalno različit odnos sa vremenom i energijom od nas. Ono što njima izgleda kao jedan dan za nas može biti hiljadu godina. Oni ne mare za Sunce, i nije ih briga da rastu brzo, i verovatno ih boli uvo za moje petrijeve šolje...
(Laughter)
(Smeh)
but if we can continue to find creative ways to study them, then maybe we'll finally figure out what life, all of life, is like on Earth.
ali ako nastavimo da nalazimo kreativne načine da ih izučavamo, onda ćemo možda shvatiti kakav je život, sav život, na Zemlji.
Thank you.
Hvala.
(Applause)
(Aplauz)