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Show Notes
This is the second of our series of discussions with key figures in the field of Bioelectricity. Ken Robinson has a long list of accomplishments in this field, covering the role of electric fields in guiding cell migration and more generally the function of electrogenic epithelia in embryogenesis. This is about a ~1 hour conversation in which he talks about his background, the history of the field, and his time in Lionel Jaffe's lab.
The papers we talked about:
http://dev.biologists.org/cgi/reprint/133/9/1657
https://pubmed.ncbi.nlm.nih.gov/12372302/
The list of bioelectricity references Ken refers to can now be downloaded at the bottom of this blog post: https://thoughtforms.life/my-reference-lists-whole-endnote-library-and-bibliography-on-bioelectromagnetics/
Aastha Jain Simes: https://aasthajs.com/ and https://www.livelongerworld.com/
CHAPTERS:
(00:00) Entering Bioelectricity Field
(11:04) Fucus Egg Polarity
(24:02) Protons, Asymmetry, Zebrafish
(37:03) Life In Jaffe's Lab
(48:11) Chick Left-Right Bioelectricity
(53:38) Electrogenic Embryonic Epithelia
(58:21) Future Goals And Recognition
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Transcript
This transcript is automatically generated; we strive for accuracy, but errors in wording or speaker identification may occur. Please verify key details when needed.
[00:00] Aastha Jain Simes: Hi, Mike. Hi, Ken. Nice to meet you.
[00:03] Ken Robinson: Nice to meet you.
[00:06] Michael Levin: Ken, thanks so much for joining us. This is really a huge pleasure for me. As you know, your work is incredibly important for the field, and I want people to hear you talk about it. I was reading your papers for years; being able to work with you on that 2002 paper in the chicken frog was a huge pleasure for me.
[00:30] Ken Robinson: I love that paper.
[00:33] Michael Levin: Have you heard anything from Thorleaf? How's he doing?
[00:39] Ken Robinson: As far as I know, he left research and has gone full bore clinical.
[00:46] Michael Levin: I see.
Ken Robinson: He had an MD-PhD thing. I think he's just doing clinical research. I've not been in touch with it.
[01:05] Michael Levin: Asta, we cannot hear you. Are you muted or?
[01:09] Aastha Jain Simes: Oh, can you hear me now?
[01:10] Michael Levin: There we go. That's it.
[01:11] Aastha Jain Simes: Ken, thank you again for your time. We're digging into the origins of bioelectricity and trying to understand the history of the field from your perspective as well. Maybe we can get started with you sharing a bit more about your background.
[01:33] Ken Robinson: Okay. My training was in physics. I was an undergraduate in physics and started graduate school in a PhD program in physics. At the end of the first year, I passed my qualifiers and was ready to start my research in physics. I spent a summer in a laboratory that I was going to work on. It was a nuclear laboratory doing low energy nuclear physics. That summer, I had a chance to talk to the postdocs and graduate students, and these were incredibly bright, hardworking people. They could do the theoretical analysis. They could build their own electronics. They could do high vacuum plumbing. They were really skilled people. But everyone that I talked to felt that their actual research project wasn't very interesting, that it was not exciting. I didn't like that. I thought of myself burying myself down in the bowels of the earth with an accelerator for five years to do something that nobody cared about. I didn't like that. So I had read just enough biology. I was in the Peace Corps in the Philippines, and we were given a locker full of books that we were supposed to just leave behind. One of those books was a little paperback called "The Genetic Code" by Isaac Asimov. I knew just enough to be able to read it and make sense of it because it was written at a simple level. So I was aware of these monumental changes that were going on in biology.
[04:15] Ken Robinson: This was in 1963 or 1964. The genetic code had just been worked out. When I got discouraged with physics, I decided to see if there was some place in biology that would be useful for me in the Purdue Biology Department. I was lucky because that department had a strong history of people coming in from physics. Michael Rossmann was there. He was an x-ray crystallographer, a very distinguished one, and he had come into biology from physics. A number of other people had joined biology from physics. I went to one of them, a guy named Bill Pack, who is a Drosophila geneticist of considerable note. He mapped every mutant that he could in Drosophila by looking at their retinal function. He'd put little electrodes on the eye of the fly and looked for deviations in the electrical response that they got, and cataloged mutants that way. Many of those turned out to be extremely interesting and important 20 years later. He couldn't take me in his lab, so he told me there's a new faculty member here who he thought was looking for graduate students. That was Lionel Jaffe, and he was willing to overlook the fact that I hadn't had a biology course since high school and invited me to join his lab. I did. It was so different than what I was going to do in physics, and I was immediately able to be productive. I actually call myself a biologist now, although I have never had a course in biology. That's how I got started. Lionel was interested in aspects of bioelectricity, and I was able to contribute there. That's what got everything started.
[07:01] Aastha Jain Simes: Wow, that's amazing that you didn't have any biology background and got into it with physics. But it is interesting to me that it seems like quite a few of the scientists in the bioelectricity field came from different backgrounds. I know Mike, you also had computer science and it's just such a multidisciplinary field. I'm curious, when you first entered the field of bioelectricity back then with Lionel Jaffe, did you know anything about it, especially given that it was the era of the genetic code? What was the state of bioelectricity back then?
[07:38] Ken Robinson: It was considered to be a curiosity. And there certainly was at that point a feeling that Lionel had a phrase for it. He called it a coliform vision, coliform referring to E. coli. He said that, and I was an innocent bystander. I didn't know these disagreements, but I learned. He felt that the people who were studying developmental biology at that time had been convinced that if you simply learned everything about E. coli and metabolic pathways in E. coli, then you would understand development, even up in humans. And he vigorously and colorfully disagreed with that view. And I began to learn then a little bit about what I guess I can call the politics of the science from that point of view. So that's how I started finding out about what these differences were.
[09:20] Aastha Jain Simes: How big was Lionel's team or people who were also thinking in terms of how Lionel Jaffe and you and some of the others were thinking about it?
[09:34] Ken Robinson: How many, how big was the lab? Is that what you're asking?
[09:39] Aastha Jain Simes: Not just the lab, but how big was the group of bioelectricity back then in general?
[09:46] Ken Robinson: Broadly speaking, we were trying to put bioelectricity on a really firm basis. We looked to the neurophysiologists for our inspiration and for how to proceed. For example, people like Hodgkin, Huxley, and Katz, who had won Nobel prizes for understanding how nervous signals are generated, we were a branch of them and we were trying to be as rigorous as they were. We were using many of the same techniques that they developed. There was a fair number of people. There were not many people, however, in developmental biology who were in fact doing that the way we were. It was a relatively small group.
[11:04] Aastha Jain Simes: Can you talk about some of the research you initially did when you first entered the lab?
[11:10] Ken Robinson: My first project was in the laboratory. Lionel's laboratory at that time was focused on how polarity emerges in an algal egg from the brown algae, Fucus and what was then called Pelvetia, now called Sylvetia. This was an interesting organism, and it's the first thing I knew and worked with, in that when the egg is released from the plant, the alga, and then it gets fertilized, and their reproductive cycle is very animal-like. You release eggs and sperm, and the sperm binds to it and fertilizes it. The first thing that this egg does is settle down and it chooses its basic axis. There is no preformed axis in these eggs. So it develops. This takes hours. The usual way that axis is formed is in response to unilateral light. If you can imagine the egg sitting in a tide pool with the sun above, it develops its rhizoid, which is its root-like structure, on the opposite side. That's directed by the light. These cells are extremely sensitive to unilateral light, particularly blue light. We were interested in what were the mechanisms by which the cell perceives the light and then responded to it. This axis is formed and it becomes asymmetrical. It starts growing out at one end, and while it's still a single cell, it hasn't even yet divided. When it does divide, the division is perpendicular to that axis. The result is you get two highly unequal cells formed that have different developmental fates. This all happens in a way that you can control it. The experimenter can, just by using light. Lionel was interested in ionic changes and membrane potential changes. One thing that I did is I started measuring ions moving—potassium, sodium, calcium, chloride—moving into and out of the cell.
[14:35] Ken Robinson: And I got experience using radioisotopes and doing these kinds of measurements on these cells. But the first significant piece of work that I did was I figured out a way to take a very thin piece of metal, which were made as filters for rocket engines. They had perfectly round etched holes in this very thin piece of metal. I found that I could fill every one of those holes with an egg, and then they would seal themselves into it. The result was you create a sort of an artificial epithelium. It was a way I was putting the eggs in parallel with each other. I didn't have the techniques for measuring ion movements into and out of the egg in a single cell. So I had to put 25,000 of them in one of these sheets. The experiment was that I would take two such preparations and put them in a chamber where I could flush fluids to them. On the underside of each one, because it was more uniformly exposed and there would sometimes be extra eggs on the top, I added radioactive calcium. But one would have light coming from one direction and the other would have light coming from the other direction. So I was forcing them to polarize one way or the other. Startlingly enough, the side that was on the shaded side, the dark side, which is the one that's going to grow into the rhizoid, showed a huge difference in the radioactive calcium influx into that side versus the other side. It's about a five-fold difference. So we had direct evidence, and this is before any morphological changes had occurred, that calcium channels were being activated on the dark side. And that was absolutely necessary for forming the axis. That paper—my photograph of a filled screen—was on the cover of Science. It was a nice little article in Science. I think that paper went a long way in establishing my career. But do you think...
[18:01] Michael Levin: In that capillary experiment, do you think those eggs were mostly communicating with the environment, or were they also communicating with each other?
[18:18] Ken Robinson: I think they were acting independently of each other. They were all just responding. I subsequently learned a fair amount more about this process. Lionel had done some absolutely gorgeous work showing that the dichroic axis of the photoreceptor was parallel to the plane of the plasma membrane. I then got evidence that the protein that was involved was in fact an opsin-like protein. We did measurements. I worked with some people in Italy who used mass spectrometry, and they could measure the opsin and the chromophore, which was the same as the chromophore in the human eye, retinal. They found that it was absolutely packed with retinal. We estimated that the membrane is practically a crystalline array of opsin-like proteins. So the action starts on the illuminated side because these cells are optically very dense and they absorb 98% of the blue light that's impinged upon them. One end receives a lot of light and a lot of excitation. That's the bright end, the illuminated end, and the dark end becomes the growth point. We found that calcium is involved there, but also cyclic GMP is involved. The signal transduction process has many resonances with human vision. Nature apparently used opsin-like proteins in many instances. The cephalopods use the same visual thing that we do, and they developed it independently of mammals and vertebrates. Unfortunately, this has ended. No one that I know is pursuing this. When light strikes the membrane, it activates these photoreceptors. The photoreceptors are coupled to the enzyme that makes cyclic GMP; cyclic GMP goes up, and that then directs the formation of an actin filament network. That's experimentally verified. I believe what happens is that vesicles are transported on these directionally aligned microfilaments, and are inserted into the membrane on the other side. I believe those vesicles contain calcium channels. That's how calcium comes in. At that level of detail, that's pretty hypothetical. I cannot cite direct evidence for that. I didn't have the resources in my laboratory to pursue that. I wish somebody would. I think it's an interesting story. We were able to show using fluorescent techniques that in response to light we can visualize a calcium gradient with high calcium at the end that's going to grow.
[23:13] Michael Levin: But was there not a story of a one-dimensional capillary tube, and you put the eggs in and they were polarizing each other? Am I imagining that? I thought there was a story on this.
[23:26] Ken Robinson: No, they weren't polarizing each other. This was Lionel's early work to try to measure them. What he was doing was he put the eggs in a capillary tube and then shone light to polarize them. It was like putting batteries in series.
[23:51] Michael Levin: They were still acting independently.
[23:53] Ken Robinson: They were still acting independently. They were not polarizing each other.
[23:57] Michael Levin: I see.
[24:02] Aastha Jain Simes: Ken, you also did a lot of work on the proton pump and took it forward. Can you talk a bit about what the proton pump is and its significance?
[24:14] Ken Robinson: Most of what I did on proton pumps was done in collaboration with Danny Adams. My interest there reflected what she was doing with Mike at the time. By that time, what I had available to me were methods of measuring proton fluxes at the level of the single cell using a moving electrode that was ion-specific. I think that tool was valuable in being able to directly show that there were changes in proton movements during early development in amphibians. Furthermore, some of the drugs that interfered with left-right asymmetry also directly interfered with these asymmetrical proton movements across the left-right axis. Those were fun experiments to do. But I consider myself to have been the junior partner in that. I was providing a technique to follow up on some of these ideas that Mike and Danny were working on.
[26:05] Michael Levin: But it was pretty remarkable because we were studying the way that embryos determine their left from their right. It was very controversial at what point embryos really know left from right. I was arguing that it's very early. Ken's data directly showed us that if you watch the proton pumping, they consistently know which side is the right side by the front. It's very, very important.
[26:31] Aastha Jain Simes: That would be pretty early on in development. The embryo itself would know.
[26:36] Ken Robinson: This was at the two cell stage. Okay.
[26:41] Aastha Jain Simes: Once you entered Lionel Jaffe's lab, you started doing some incredible work. What was the state of the field a decade later? What was some of the most significant research being done in bioelectricity then? Would this be the 1970s?
[27:04] Ken Robinson: That was actually a period of tremendous growth. I was Lionel's first graduate student. He started out his career as a professor at Brandeis, then he went to Penn, and then he came to Purdue. But he had never had a graduate student who completed a PhD with him. He was sufficiently pleased with the way I turned out that he began recruiting in the physics department from their graduate students, but he got three more graduate students from that. The first one after me was Rich Nuccitelli. The laboratory then began to increase significantly in numbers. So at one point, Lionel may have had 10 or 15 graduate students and postdocs in there. Mu-ming Poo joined the lab as a postdoc, and he and I collaborated. After I finished my PhD, I hung around there for another year or so, just because everything was moving so fast and there was a lot going on. Lionel, meanwhile, began to look at higher-level things, regeneration of amphibian limbs. Richard Borgens came into the lab, and he was a joint graduate student with Joe Vanavel, who was interested in these matters. So that stuff changed dramatically in those years. Poo and I showed that if you expose cells to an electric field—just pass current through the medium that they're growing in—you could cause membrane-bound receptors of a certain charge to migrate directionally in the electrical field that we applied to them. I later showed, and Poo then independently showed, that these same tiny electrical fields could direct nerve growth in culture. That got the attention of a lot of other people; you could actually guide neurons with small electrical fields. So there was really a huge increase in interest and number of people working on these matters in the 70s.
[30:32] Aastha Jain Simes: But what were some of the pushbacks then, or were there any pushbacks from other people about the field?
[30:38] Ken Robinson: There was resistance to the idea that electrical fields, endogenous, naturally occurring electrical fields, were playing any role in polarization. I think there was a strong bias toward thinking that all communication between cells was probably chemical and dependent on diffusion, and real resistance to the idea that these electrical currents and electrical fields that we measured inside the embryos were playing a role in polarizing them. I would say today that still is not a settled issue at all.
[31:45] Aastha Jain Simes: So when you did work on showing that neurons respond to these electrical fields, were people's reactions that this is limited to neuron cells and doesn't work for the other cells in the body, or even for neurons—was there resistance?
[32:01] Ken Robinson: Well, we showed directly on neurons in culture. That worked as well. People believed it. The data was very sound and it was very visual, so that was straightforward. But the resistance was that we did not show that in the intact embryo, that endogenous fields, fields that were already there, were actually affecting development and movement, migration of neurons and migration of cells. I must say, that's one of the failings of what we did. Toward the end of my career before I retired, I was trying to work out ways to do that directly, to do it in the intact embryo. I was envious of what was going on in Mike's lab and what he was able to do. I was trying to meet that. So I thought, okay, first of all, to do this, I need a genetically tractable system and a small, transparent animal that makes a small, transparent embryo and everything. That led me to zebrafish. I had hoped that we would be able to actually visualize growing neurons in zebrafish embryos and actually measure and manipulate the local electrical field inside the embryo and see the response of the neurons as they were developing. To get going on that, we set about repeating the experiments that we had done with Xenopus in cultured neurons. Those cultured neurons were obtained from the developing nerve cord of the embryo. So we did the same thing with zebrafish. We took out the developing nerve cord, disintegrated the cells, put them in culture, grew them, and applied electrical fields to them. They didn't respond at all. That was a real setback in my plan. They just didn't respond. My fellow scientists, some of whom I had trained in my own laboratory, did not like that result and its implications. In fact, I was never able to do the experiments that I envisioned, partly because we couldn't even show at the culture level that the cells were responding to electrical fields. We did some work using zebrafish on keratocytes, and they are exquisitely sensitive to electrical fields. There are some people continuing to work on those aspects of it, whether endogenous electrical currents are involved in guiding wound healing in these organisms.
[37:03] Michael Levin: What was it like in Lionel's lab? It was an incredibly productive period, so much good stuff coming out, just some real characters. What was that like for you and in general?
[37:15] Ken Robinson: Oh, it was a blast. It was a lot going on. There were a colorful cast of characters and some amazing science that was hanging around, totally separate from the electrical field stuff. I wasn't part of it, but I was witness to it: the first measurements of calcium inside cells using optical techniques, the photoprotein aequorin, the bioluminescent protein aequorin, which was before its accessory protein, GFP, had even been discovered. This was just purified aequorin from a jellyfish. Aequorin, when a molecule binds two calcium ions, then emits a photon and it's dead at that point. Lionel had the vision to inject aequorin into a fish egg, medaka, a clear fish egg, and then, using a photomultiplier tube, measure light output when the egg was fertilized. I very well remember when they were doing it: they had an extremely sensitive photomultiplier tube and the egg was sitting right on the photocathode. They added sperm in a completely dark room. The signal that was being recorded electrically blew it off. They had to change the gain by three orders of magnitude to keep the signal on the screen. Lionel then went to the astronomers; they had imaging devices that worked at the photon-counting level. He collaborated with a group at Princeton and was able to actually visualize the calcium explosion that occurs when the egg gets fertilized. You could see it start at the point of sperm entry and then spread around the egg. That turns out to be a universal truth. All eggs—plant, animal, algae—no exception. At fertilization, there's an explosion of calcium that is both necessary and sufficient to start the developmental process. That was being done right next to me. I didn't do that work, but I was a witness to it. That was truly an exciting era in science.
[40:59] Michael Levin: What was Lionel doing that enabled this amazing fertility, the creativity, all these great people? Was there anything in particular you would attribute that to?
[41:15] Ken Robinson: I would say that the defining characteristic was Lionel's absolute pure curiosity. I remember once somebody was doing some work and the results were absolutely not what was expected. And they sort of shot down a major line of work. And I remember Lionel's reaction to that was so matter of fact and accepting. He wanted to make sure it was right, but OK, we scrap that and we start all over again. And this actually happened to me. I'd be working away in the lab until late at night, and sometimes I'd get some exciting results. I could call Lionel at any hour of the day or night and he would be eager to talk about it and work through it with me. He had a kind of, almost a purity of perfect scientific interest. Now, on the other side of the coin, Lionel did not have a good grasp of the impact of what he said on other people. He couldn't calibrate, and he could be brutal. He mostly did not intend to be harmful; he didn't recognize what effect he was having on people. So he made a lot of enemies and was not widely beloved in the field. I think that was a severe enough problem that it interfered with the perception and acceptance of his work. It's interesting: his daughter, Lorenda, with whom I collaborated, was not too long ago elected to the National Academy. I was responsible for getting her first job at the University of Connecticut Medical School where I was at the time, and she's still there. Lionel never was. I think in part this was personal; his personality interfered with things.
[44:56] Aastha Jain Simes: And he also.
[44:58] Ken Robinson: Sorry, go ahead.
[44:59] Aastha Jain Simes: No, go ahead.
[45:00] Ken Robinson: The last five years of Lionel's career in science, he had no grant support; he didn't even have a laboratory to work in. It did not end well.
[45:27] Aastha Jain Simes: Did he also try to instill camaraderie or have certain ways of motivating people, or was he mostly leading by example through his sheer curiosity?
[45:42] Ken Robinson: I think mostly he was a font of ideas. He had an understanding of physical principles that was extraordinary for somebody trained as a botanist. Lionel was brilliant. He had absolutely no difficulty with the mathematics and physics of what he was doing. His physical insights generated so many ideas, and he put those out there. He was accessible. You could talk to him and he would tell you, and you could work through ideas. He had ideas about how to do experiments, which were sometimes not very good. Something that both Rich Nuccitelli and I brought to Lionel's laboratory was maybe better laboratory skills than Lionel himself had. He was held back by being overly cautious in the laboratory. Things had to be absolutely perfect. I'm thinking about the development of the so-called vibrating probe, which you could use to first measure currents at the single cell level. Lionel had this idea for a long time and had it lying around. I don't think it would have ever gotten built and turned into a functional instrument without Rich Nuccitelli doing it. Rich had a real knack in the laboratory of how to put things together and make them work, more so than Lionel did.
[48:11] Aastha Jain Simes: We spoke to Rich as well, and he also had very fond memories of working in Lionel's lab. I know you and Mike have also collaborated on quite a few projects. What have some of those been and what's that been like?
[48:27] Ken Robinson: I first knew Mike when I got this large packet in the mail. It was a bibliography of everything that had ever been written about bioelectricity. He asked me to look at it. I'd never heard of it. I think Mike was at that. I don't know if you were a graduate student, Mike, or a postdoc.
[49:01] Michael Levin: I was an undergrad. This was this was what?
[49:03] Ken Robinson: He was an undergrad. I looked at it and I was astonished by it, that it was so absolutely complete. I wondered what had motivated this guy to put this all together. We later met at a scientific meeting. By that time you were a postdoc. You started telling me about your ideas on left-right asymmetry in the chick embryo. I thought there's something I can contribute to. So we started a collaboration and I had a Swedish postdoc who came to my lab fully funded from the Swedish government, and we were looking for a project for him, so I suggested that he do this. The idea, what we wanted to do was to look across the midline of the developing chick embryo, the left-right midline, and look for differences in the membrane potentials of the epithelial cells on one side versus the other. My first idea was to do this with electrophysiology, microelectrodes. Stick microelectrodes in one side and then the other side. That turned out to be impractical. There was too much noise in our measurements and it wasn't working. For once I had a good idea. I thought this is a planar situation. There are a bunch of cells here. They're all the same. The only difference in these epithelial cells is they're on one side or the other of the neural tube. I thought this would be a good place to use imaging. There are these so-called slow membrane potential dyes. They're really not measuring membrane potential directly. They're not responding to membrane potential, but rather they accumulate in the cells according to the membrane potential of the cell. We could load this epithelial sheet, expose it to the dye, and then look how much of the dye was taken up by the cells with one confocal image. We did that and it jumped out that it was very clear that the membrane potential of the cells on one side was different than the membrane potential of the cells on the other side. Furthermore, some of the reagents that Mike had found interfered with left-right asymmetry also destroyed that electrical potential asymmetry. All of the work that Mike had done up to that point, added to what we could add with the imaging, made for, I think, quite a remarkable paper, the paper that we published in Cell. That was an awful lot of fun to do those experiments. Unlike most of the time, I actually had an idea that worked out. Wow, that worked. So that was fun. I think that also was a useful thing for the whole field because Mike and Nanny Adams made use of that technique in a lot of other circumstances.
[53:38] Michael Levin: Following up on one thing, you point out that this was an epithelial situation, and you have this amazing paper long before that about the epithelium as a generator of developmental information.
[53:49] Ken Robinson: Yeah.
[53:50] Michael Levin: If you could talk for a few seconds about that, because I think it's a really profound notion, that information for these things gets generated on a 2D surface, and then is able to instruct deep three-dimensional structures underneath that. I found that very inspiring. Anything you want to say about the epithelium and the role of it in general?
[54:13] Ken Robinson: The epithelia of animals are powerfully electrogenic. That's what they do: they are to the embryo what the plasma membrane is to a single cell. They separate outside from inside, and they do this by transporting ions. They pump sodium in and develop not a membrane potential, but a transepithelial potential. If you make a hole, any kind of a hole in that epithelium, current comes rushing out of that hole. It's so easy to measure it. I used to do a demonstration in my undergraduate teaching. I had a very sensitive galvanometer, a current measuring device, and I would take my fingers and dip them into beakers that were then electrically connected to the galvanometer. I did this for undergraduate students: you put your fingers in it and not much happened. The meter flopped around some. Then I would take a razor blade and make the tiniest nick in one of my fingertips and put it in. The current was just really obvious. The current was pouring out of the cut surface, the cut wound. That's the external current. But those same currents flow in closed loops. So there are also currents flowing inside the embryo. Furthermore, it turns out that it doesn't just happen when you make a nick in it. It happens during embryonic development that there are places of low electrical resistance through the epithelium. The embryo then drives huge currents. I'm talking about the frog embryo, but it's true of other embryos as well. I still believe, and we had reasonable evidence to support this, that those currents are involved in organizing the development of polarity inside the embryo as it develops. Because if we interfered with those currents, or made ectopic sources of currents, we got profound effects on the subsequent development of the embryo. This is work I did with Kevin Poteri, and a couple of really nice papers came out of that work on both chick and frog.
[58:17] Aastha Jain Simes: Just some closing. Go ahead.
[58:20] Ken Robinson: Go ahead.
[58:21] Aastha Jain Simes: What are some of the advances you'd like to see the field of bioelectricity make?
[58:32] Ken Robinson: The major thing I would say is that I would like to have it demonstrated unequivocally that these currents that I've just been talking about are in fact guiding cells and affecting behavior of the cells in the intact embryo, either through imaging or whatever techniques. But that has not yet been done. We showed on a macroscopic level of the whole embryo that if we interfered with the currents, we interfered with development. But we didn't show what the specific targets were of these currents and the fine detail of where they were working. To show directly that at this stage of development these currents are guiding these cells would be my goal. If I were working, that would be what I would want to see developed, and that has not been done.
[1:00:04] Michael Levin: Is there anybody in this field that you think needs to be more known about? Who, if anybody, hasn't gotten credit? We know the major players that we talk about, but is there anybody that you feel hasn't been heard about?
[1:00:23] Ken Robinson: I would point to one person. He's not unknown, but he was a former student of mine, a graduate student and a postdoc as well. His name is Mark Meserly. He's at South Dakota State University. He is a biophysicist, par excellence. He is doing work on understanding the mechanism of electrical fields and their interactions. Particularly, he's focusing on the role of electrically induced water movement in cells and doing fabulous work on that. I would like to see Mark's work better known and better recognized.
[1:01:26] Aastha Jain Simes: All right, Ken. Thank you so much. Is there anything you'd like to add as we close out?
[1:01:31] Ken Robinson: I've said everything I have to say. It's been a pleasure to meet you and really fun to talk to you again, Mike.
[1:01:40] Michael Levin: Great to see you, Ken. Thank you so much.
[1:01:43] Aastha Jain Simes: Thank you so much for your time.
[1:01:45] Michael Levin: All right.
Ken Robinson: Be well. Bye. Bye everybody. Adios. Bye.
