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Chemistry Research Roundup


Chemistry is sometimes called the central science because it sort of connects physics, medicine, astronomy and more and that was on display at the American Chemical Society Conference that wrapped up yesterday. And there was a bunch of really interesting research presented at the meeting from eradicating bed bugs, to using biotechnology for a better insect repellant, to finding a new way to treat AIDS.

But you know what we're going to start off with? Whiskey, yeah. They talked about whiskey there. What is the difference chemically between rye, whiskey, bourbon? How does it get its nice mellow flavor and just what's going on in the 53 gallon oak barrel aging for decades? Here to talk about that is Thomas Collins. He's the director of research for the food safety and measurement facility, University California, Davis. Welcome to SCIENCE FRIDAY.

TOM COLLINS: Well, thanks. My pleasure to be here.

FLATOW: What brought up that topic for discussion?

COLLINS: Well, the topic sort of follows the work that I had done on my Ph.D. I studied oak aroma and flavor chemistry for the wine industry. At the time, I worked for a large winery in California that owned a cooperage and we did a lot of work looking at oak chemistry and how it impacts the flavor of wines.

FLATOW: Well, let's talk about it. Let's go right to that. How does oak chemistry impact the flavor?

COLLINS: Well, the toasting process and whether this is toasting for wine or toasting for whiskey or charring for whiskey...

FLATOW: Toasting, what is that?

COLLINS: So toasting is the process once the barrel has been formed into shape, of heating it over a fire to basically heat it enough to break down some of the structural components of the wood itself. And so you get some flavor compounds that are released from the breakdown of lignin or cellulose or some of the other structural components of the wood.

And then, when you put wine, or in this case whiskey, into that barrel, ethanol is a very good solvent and it will extract some of those components from the wood itself and that becomes part of the composition of the wine or the whiskey.

FLATOW: Now, I heard that there is something like 4,000 different components in whiskey.

COLLINS: So not necessarily in any particular whiskey, but when we looked across a set of 60 or 70 whiskeys, which we did in this case, the total number of compounds that we found across the entire set was between 3,000 and 4,000 depending on the samples that were in the set. We went through a series of statistical steps to narrow that number down to a manageable number that we could use in our multi-varied statistical techniques to be able to differentiate between the different types of whiskey.

FLATOW: And do they account for all the different flavors of...

COLLINS: So, the 30 to 50 compounds that we used for our statistical analysis, many of them would be compounds that would be important to the flavor of the whiskey, or the wine. But they would not be nearly all of the things that are contributors to the total package. But they're the ones that we were able to use to differentiate between the different types of whiskeys.

FLATOW: When you put the whiskeys in the barrel, what actually happens in there to change the flavor?

COLLINS: So the...

FLATOW: What is aging all about, I guess is what I'm asking?

COLLINS: So the aging process really is the process of extracting these various flavor and aroma compounds from the wood itself. There are also some other reactions - oxidative reactions - that affect both the components that came with the distillate when it was put into the barrel and also things that are extracted from the wood itself. So it's a combination of extraction and oxidation. And, you know, ethanol's a very good solvent and at 60, or, yeah, 60 percent alcohol, it's going to extract the wood very thoroughly.

There's another aspect of aging in charred barrels is that there is a surface layer of charcoal on the inside of the barrel. And that actually acts as an adsorbent and removes certain components from the distillate as well. And so there are some things that are extracted or adsorbed into the wood itself.

FLATOW: Now wine is stored in casks also. Is there something different going on there than what goes on with whiskey?

COLLINS: Well, I think there are probably a couple of things that are different. The first is the difference in ethanol concentration. Typically wines will be somewhere between 12 and 15 percent ethanol. And the whiskeys are going to be much higher, typically somewhere between 50 and 60 or so when they go into the barrel. So there's a difference in the concentration of the solvent. There are certain things that will be soluble in whiskey that wouldn't be soluble in wine because of the lower ethanol content.

FLATOW: Is there a fingerprint, sort of that you know that this whiskey came from XY barrel or distiller or country that's left behind in the whiskey?

COLLINS: So that was actually the question we were trying to sort with this research was, can we use some of the components that are in the whiskey to tell us something about where that whiskey came from or what kind of barrel it was in or what distiller produced it? And we were able to show some compounds that were different between, for example, blended American whiskeys and bourbons were pretty easy to separate. And the big difference was that the blended whiskeys were generally not - didn't have as much wood influence.

And so the levels of components that came from the wood were much lower in those whiskeys. And so they were relatively easy to separate. When we looked, for example, at rye whiskeys versus bourbons, and the difference really between the two is in the grains that are used in the initial fermentation. So bourbons have to be at least 51 percent corn while a rye whiskey has to be at least 51 percent rye as the starting material.

FLATOW: Tom, can I - hold the thought because we have to take a break.


FLATOW: We'll come back and talk some more about this. Talking with Tom Collins about whiskeys. If you want, our number 1-800-989-8255. You can join in the discussion. I know this is something you're interested in. Stay with us. We'll be right back after this break. I'm Ira Flatow. This is Science Friday from NPR.


FLATOW: This is Science Friday. I'm Ira Flatow. We're talking about the chemistry of whiskey with Tom Collins, director of research for the Food Safety Measurement Facility at the University of California, Davis. Our number, 1-800-989-8255. And, Tom, you were - when I rudely interrupted you, you were talking about the difference between the compositions of bourbon, malt, all that kind of stuff like that.

COLLINS: Right. So just to step back a minute, I had said that bourbons had to be at least 51 percent corn. And often they're much higher than that, and the same with rye. Rye has to be at least 51 percent rye, but it can be much higher. And interesting thing occurred when we went to look at the difference between bourbons and ryes. We were able to separate some of the rye whiskeys quite readily from the bourbons based on their composition.

And when we looked at why we could separate those whiskeys but not others, we found that the whiskeys we were able to differentiate were primarily whiskeys from distillers that focused on making rye whiskeys, whereas the ones that we could not separate from bourbons largely came from distilleries that make both bourbon and rye.

And so a couple of possible reasons why that might be is the bourbon producers might have a house style, a set of conditions in how they make their distillations, the types of things they do with their barrels in terms of aging might be a house style that actually is more critical than the grain itself, whereas the distilleries that focus on rye might be using more rye in their mash bill. And they might be doing things differently in order to make a whiskey that really reflects rye the way they wanted to see it.

FLATOW: Is the house style distinct enough that you could tell a counterfeit from the real thing?

COLLINS: I believe we could. The house styles are significant enough that we can also - when we look at the data distillery versus distillery, we can see differences between some but not all of the bourbon distilleries. So if we just focused on bourbon distilleries, there is a spread across those in their product range from low to high fits within a sort of defined area. And it's different from one distillery to the next (unintelligible)...

FLATOW: Let me get...

COLLINS: Go ahead.

FLATOW: No, I'm sorry. I wanted to get a question in from a listener before we run out of time. Let's go to Boston. Sanja, welcome to Science Friday.

SANJA CALLER: Thank you. Thanks for taking my call. Very interesting program. I was wondering if you guys could shed some light on dark scotch or dark whiskey comes from.

FLATOW: Dark, what makes it dark? Good question.

COLLINS: Good question. I'm not sure what makes it dark. Are we talking about dark in terms of the color?


COLLINS: More than likely it has to do with the aging conditions, the type of barrel that it was in, how long it was in that barrel. And then probably things related to the temperature that the barrel was stored at and maybe the humidity. So there are some differences that come about from the conditions under which it's aged.

FLATOW: What questions do you still need - you'd like to be answered about whiskey?

COLLINS: So one of the things that we wanted to try and get further into is the - there are a number of components that go into the composition of whiskey starting with the grain. And we'd like to understand better the differences between whiskeys made from corn and rye. And to do that really we need to go back and look at the fresh distillate before it goes into barrels so that we can focus on differences due to grain without having to look through the components that come from the wood. So that's one.

I think there would be some interest in looking at differences in pot-distilled whiskeys versus column-distilled whiskeys and trying to understand better how the operation of the still affects the final product.

FLATOW: Right.

COLLINS: And then I'm always interested in looking at the wood composition because that's been where I've come from.

FLATOW: Yeah, one last question for you. If you don't drink a bottle or - how long does it stay good? Does it stay forever or does it start to degrade with age in the bottle?

COLLINS: Well, I think over a long enough period of time there would start to be some degradation and loss of volatiles. But it's not something that has to be consumed within a week or even a month. It'll - generally once you open a bottle it'll be good for probably several months before you would notice any difference.

FLATOW: And an unopened bottle, how many years could it stay?

COLLINS: An unopened bottle?


COLLINS: Well, an unopened bottle is actually a pretty stable environment for the whiskey. So generally once it goes into an unopened bottle it's probably - it'll be reasonably consistent for a number of years.

FLATOW: All right. Thank you very much, Tom, for taking time to be with us today.

COLLINS: Oh, absolutely, my pleasure. Thank you.

FLATOW: Tom Collins is director or research for Food Safety Measurement Facility at the University of California, Davis. Next, bed bugs. Oh yeah, right. Just the words strike fear. And unfortunately they are the perfect pest. They thrive indoors. They seem to be able to outsmart almost every pesticide we squirt at them. Their protective secret lies in their tough shell and sort of just laugh off the insecticides.

But now researchers at the University of Kentucky have identified the genes in the bug's hard shell and use them as targets for attacking the bugs. Susan Jones is a professor of entomology at Ohio State University in Columbus. Welcome to Science Friday.

SUSAN JONES: Thank you.

FLATOW: So you looked at the genes in the bed bug shell. Can you tell us what you found?

JONES: Well, this study was actually from the University of Kentucky. And I'm at Ohio State University where we have also been looking at resistance in bed bugs. And we had found data suggesting that a lot of the genes that were involved in resistance were highly expressed in the insect cuticles. But fortunately for us University of Kentucky actually did the remainder of the very intense studies involved on this and found that the insect cuticle is a sight of very highly expressed gene activity.

So there's a bit of a misnomer when you say that it's a very tough thick cuticle because it's actually a very soft cuticle that can easily be damaged. And a lot of the press picked up how, you know, you can't squish a bed bug and such. And I'm here to tell you that they can very easily be damaged, particularly when they have recently fed. They're almost like a little red balloon and they can easily be damaged at that point.

But even whenever they're very flat you will - you can take a newspaper and slap them and you will cause enough damage to, as we say, mechanically control these bugs rather than chemically controlling the bugs.

FLATOW: What is there about the genes that they're able to fight off the pesticides?

JONES: Well, what they found at Kentucky was that these genes are - there are a lot of different resistance mechanisms that are being employed and being expressed in the bed bug skin or cuticle. And some of these are involved in metabolic resistance. There are others that are involved in target sight resistance. And then others that are involved in other mechanisms as well including the penetration resistance.

FLATOW: And so there are some genes that allow them to pump out the pesticides that are on the shell? They can just pump them out so they never get to the inside of the bug?

JONES: That's right. That's exactly right. That's one way of looking at it is that they have different enzymes and different mechanisms where they are actually able to degrade and biochemically change the insecticide. So they can then excrete it from the outside of the body without it ever being able to reach the target sight, which is going to be the insect nerve system.

FLATOW: Now they've looked at the pesticides called pyrethroids. How are these supposed to work and how do they not work on these bugs?

JONES: Well, the pyrethroids are affecting what we call the voltage gated sodium channels in the membrane of the nerve.

FLATOW: I was afraid you were going to say something like that.


JONES: But let me just say that the - years ago when we brought - had DDT on the market, it was a chlorinated hydrocarbon, so a different class of chemistry. But it basically worked the exact same way as pyrethroids work. And so what this means is because of bed bugs throughout the world being exposed to chlorinated hydrocarbons, we have a condition that's called cross resistance.

So where you have an insect that was exposed to chlorinated hydrocarbons and you have an insecticide that - I mean, a bug that's exposed to pyrethroids, a different class, now they're both having - expressing resistance without one ever necessarily being exposed to that chemical. And...

FLATOW: So are they out-evolving the pesticides we throw at them?

JONES: Oh, as we speak, they are...


JONES: ...readily evolving. And you have to understand that bedbugs have an incredibly rapid lifecycle. These little bugs can go from egg, through five immature stages, to reach the adult stage in as quickly as three weeks time. If it's a little - and that's at temperatures that are fairly warm, 85 degrees. But if you decrease the temperature to about 65 degrees, they still are going to complete that lifecycle and become reproductive adults in only three months time.

FLATOW: Wow. Wow.

JONES: So they're - you know, an insect that has a very fast lifecycle is one that is just prime to have to be able to develop resistance mechanisms, to kind of thwart these different pesticides that we are throwing at them.

FLATOW: Well, if we know now what genes are active in the bedbug's shell, can we target those sites in the shell a little better now?

JONES: Oh, yes. Yes. And that is one of the really exciting things about this study is that yes, indeed. That would be the idea, is maybe we can find a way to circumvent this. But this is going to be something that is going to take intense study. And it's going to be years before we could possibly come up with something like that.

So, in the meantime, bedbugs are the most difficult insect to control in the urban environment. And we suggest that people use a variety of different strategies, rather than just relying on, say, insecticides. These insects are very susceptible to extremely high temperatures, and so heat is another thing that can be used to help combat bedbugs.

But sanitation is also an issue that many people tend to neglect. And so you can vacuum up large numbers of these bugs and physically remove them from a site. And so now, we're totally getting away from insecticides, and we are drastically reducing the population. Laundering clothes, particularly putting them in a clothes dryer, it's important that the temperature is up to about 120 degrees Fahrenheit. And you want it to be at that temperature for 30 minutes. And that's a way to disinfect your clothing and such.

So we have to basically try to throw everything at these bedbugs.

FLATOW: Where was their natural habitat? Fid they come from outdoors or...

JONES: Well, bedbugs do...

FLATOW: ...where do they live naturally?

JONES: OK, bedbugs do not live outdoors. They only live indoors. And we think that they probably evolved in caves and were probably feeding - there was an insect that was feeding on bats. In fact, we still have what's called a bat bug that looks almost identical to a bedbug. But sometime in our human history, as humans moved into caves - again, a very protected environment - then some of these bugs start - adapted and started feeding on humans.

And through time, lo and behold, we have the bedbug, which is specialized on human blood and will feed on alternate hosts, but it really prefers to feed on humans.

FLATOW: I'm Ira Flatow. This is SCIENCE FRIDAY, from NPR. I'm talking about bedbugs with Susan Jones.

I guess it's also difficult to get a pesticide in the bedbugs, because they feed on blood, right - as opposed to cockroaches or something like that - and have to ingest it that way.

JONES: Yes. And the ordinary person doesn't think about insect mouthparts, but this is critical for understanding how to go about strategies for controlling insects. So, for example, a cockroach has chewing mouthparts, so it'll be able to chew on a bait, or something, and actually get the chemical into the gut system through just directly feeding on it.

Well, bedbugs have piercing, sucking mouthparts. And so they are going to insert that in through the human skin. And they are going to obtain a blood meal that way. So it's primarily through their external surface, through their skin that they are being bombarded with insecticides, whereas something like a cockroach, you can be feeding it a toxic bait, and you can easily kill it that way.

FLATOW: Professor Jones, how did you get interested so much in bedbugs?


JONES: Well, I have been doing entomology for going on 35 years. We did not even talk about bedbugs when I was doing my graduate studies. In fact, only in the last 10 to 15 years did I even hear about bedbugs, because they were virtually gone from the United States. And I was getting calls from people throughout the State of Ohio, particularly in the Cincinnati area, who were telling me that they were suffering immeasurably from the bedbug infestations in their homes.

And so I became - over the next couple of years - greatly involved in various task forces in Ohio, as we tried to come up with some ways to combat these bugs. And the bad news is, right now, we don't have any way of combating them. They are continuing to increase exponentially, and they are hitchhikers. They will readily move from place to place.

FLATOW: Such good news you bring us, Dr. Jones. But it's good to see that you're on the case.

JONES: I really - this is not something that I ever expected to be working on.


FLATOW: That's true. We've run out of time. Thank you very much for taking the time to be with us today.

JONES: My pleasure. Thank you.

FLATOW: You're welcome. Susan Jones, professor of Entomology at Ohio State University in Columbus.

We're going to take a break and come back and talk about some powerful insect repellent, made from a compound found in grapefruit. We don't know if it works on bedbugs, but it might work on some other insects. So stay with us. We'll be right back after this break.


FLATOW: This is SCIENCE Friday. I'm Ira Flatow. We're talking this hour about chemistry and highlights of the American Chemical Society meeting that just wrapped up in Indianapolis.

And we're going to talk more about something - well, we talked about pesticides before in the last segment. We're going to talk about something new, here, a little bit different. This is kind of an interesting pesticide. Nature has been evolving better chemicals for millions of years.

My next guest says we could use these natural libraries to investigate alternative pathways. And we're going to talk about pesticides. And before we get to get to that, let me introduce my guest. Richard Burlingame is vice president of Research and Development at Allylix in Lexington, Kentucky.

Thank you for joining us.


FLATOW: You work with something called nootkatones. Is that - what is that? What is a nootkatone?

BURLINGAME: Well, nootkatone is a compound that's - it's called a sesquiterpene. It's a 15-carbon compound that's a member of the class of the compounds called terpenes, which are the most diverse class of natural products. It's a compound that is the defining flavor in the fragrance of grapefruits. So if you cut open a grapefruit, what you smell and what you taste when you eat a grapefruit is nootkatone.

FLATOW: And this is found naturally in the grapefruit.

BURLINGAME: That's right. And it's found in other sources, too. It's also found in Alaska yellow cedar, for example.

FLATOW: And it's good as an insect repellent?

BURLINGAME: Yeah. And it's not surprising that it would be useful as an insect repellent. In fact, terpenes in general are compounds that serve protective functions for plants. So they can act as repellents for harmful insects, or attractants for beneficial insects. So that is a reflection of their natural world.

FLATOW: So is there enough of nootkatone, or are there enough grapefruits that we can take them and make insect repellents out of them?

BURLINGAME: Well, yeah. That's what the problem is. Nootkatone is present in pretty low abundance in grapefruits. And grapefruit peels are something that really is in limited supply, at least for applications such as this. So, we at Allylix are developing technology to produce compounds like nootkatone more cost-effectively, and also produce it more sustainably and reliably.

So we've developed a yeast system in which we have genetically engineered yeast to produce various terpenes, and produce those terpenes by fermentation, then from the yeast strains. And thereby, we can produce these compounds in large quantities from abundant and inexpensive raw materials. So we can obtain large amounts at much lower cost than it would take to extract them from natural sources.

FLATOW: Now, give us an idea of how effective these compounds are compared to other compounds.

BURLINGAME: Well, nootkatone is effective against a variety of different insects. It's effective against mosquitoes, ticks - including the tick that's responsible for the transmission of Lyme disease - bedbugs and fleas. So it is a pretty broad spectrum.

FLATOW: And since it comes from a grapefruit, or is derived from that, we would assume that it's pretty safe, then.

BURLINGAME: Yeah. It's on the GRAS list of compounds. GRAS stands for generally regarded as safe. It's a component of grapefruit. I don't know of anybody that's ever died from overexposure to grapefruits. So it is a safe compound.

FLATOW: And when are we going to be able to this in our, you know, hiking store?

BURLINGAME: Oh, I'm not sure exactly. It's still in the research stage. They're still testing it against various applications: what kind of doses are unnecessary to - are the effective doses for it, what's the best formulation. And on top of that, there are still some regulatory issues that need to be resolved. It has to be registered with the EPA, for example, to use it in the environment. So it'll still be a while before it's actually on the market. But it could be in the next few years.

FLATOW: Is this - would you apply this to your skin, like you do DEET, or something like that?

BURLINGAME: Yeah, you could. And it's been tested as an insect - a topical insect repellent. One nice thing about nootkatone is it's much less volatile than DEET or some of the other contact repellents. It has a very low vapor pressure. So whereas something like citronella, which is in citronella oil - may be effective for about 15 minutes, indeed is effective for an hour, maybe two. And nucatone, as a repellant, will last all day.

FLATOW: Wow. Well, thank you for taking the time to be with us. You say it will repel bed bugs?

BURLINGAME: Yeah. We have studies that do indicate it has repellant activity against bed bugs.

FLATOW: So, it won't kill them but it'll keep them off of you?

BURLINGAME: Well, it's still fairly early stage research but we do have evidence of it repelling.

FLATOW: Boy, that'll sell it itself, I think. Good luck, good luck to you. We'll wait to see that. Richard Burlingame, thanks for taking the time to be with us today.

BURLINGAME: Well, thank you for having me.

FLATOW: He is vice president of research and development at Allylix in Lexington, Kentucky.

FLATOW: Nature has been evolving better chemicals for millions of years, and my next guest says we can decode these natural libraries to investigate alternative pathways to treat diseases, like Alzheimer's, cancer, AIDS. Paul Wender is the Bergstrom professor of chemistry and professor of chemical biology at Stanford University. Welcome to SCIENCE FRIDAY.

PAUL WENDER: Thank you, Ira. It's a pleasure to join you and your listeners.

FLATOW: You're welcome. Your lab covers a wide range from AIDS to cancers to Alzheimer's. What is the commonality between all of these that you're looking at?

WENDER: Well, it's the connection. We're connecting the dots between unsolved medical problems, therapeutic needs, whether it's Alzheimer's, AIDS-resistant disease and ways in which nature is providing clues to address those kinds of problems. So, in the last 50 years, we have developed the tools - we, the scientific community have developed the tools that allow us to go in and to begin to understand what nature has been doing over the last 3.8 billion years of chemical experimentation, and we're now extracting that information and trying to apply it to unmet medical needs.

FLATOW: When you say developing the tools, what do you mean by that?

WENDER: Well, I mean, the tools have been developed for much of what we need to read these libraries. These are the instruments, spectroscopy and all of the tools that allow us to see the world, see the molecular frontier, if you will, and begin - it's like going into a conventional library but now we could actually see many orders of magnitudes smaller than we had previously and we could begin to see how nature has solved problems and take inspiration from that and apply it to unmet needs that we have.

FLATOW: Give me a for example.

WENDER: Excellent question. And one of, I think, of very effective example is to think about flight - heavier than air flights, such as a bird and modern aviation. One is looking at nature, you extract knowledge from it. It's the concavity of a bird's wing that provides the lift. And one then use that information to create things that have never existed in nature but obviously are providing solutions for transportation and a lot of other needs in our modern world.

FLATOW: So, what examples in nature are you using to then conquer these diseases we're talking about?

WENDER: Well, we're looking at molecules that regulate pathways in cells so that we can, one, understand how those pathways are regulated, then using that knowledge we could see how they might misregulated in diseases. And then we take molecules from nature and see if we could re-correct the misregulation that occurs in certain diseases. Some of...

FLATOW: Have you had success with some of them?

WENDER: Oh, absolutely.

FLATOW: Well, give us examples of that.

WENDER: Well, one of these is Prostratin. It's a molecule, which occurs in a tree in Samoa and various other places on the planet and it became a lead through the pioneering efforts of Paul Cox at Brigham Young and through our own National Institutes of Health Foundation, became a lead of thinking about strategies for the eradication of AIDS. So, a few years ago, we published a way of making that molecule. And in our research, what we tried to do is to go beyond nature, to think about how nature uses these molecules and then to design things that might even function better than what nature has done. It's a lot like the bird and modern aviation. So, we have actually now created analogs of Prostratin that are 100-fold and some are 1,000-fold more effective in purging the latent HIV virus from reservoir cells.

FLATOW: So, in other words, you can combat the HIV and think that you have eradicated it from the blood, but there are reservoirs waiting to jump out again. And you found something that will drain these reservoirs, so to speak?

WENDER: Exactly, exactly. We have found compounds - well, we, meaning the scientific community. Again, Paul Cox, the healers of Samoa, the NIH. We're working with Jerry Zach, we're working with the National Institute of Allergy and Infectious Diseases. It's a scientific village, if you will, that's being brought to bear. But to pick up on your key point, yes, the HIV problem is a two-problem problem. We have an active virus and a latent virus. The latent virus is in reservoir cells. We do not have any way of addressing the latent virus. And what these drugs do is they activate the latent virus and purge it from these reservoir cells. And we think that this is a strategy that might actually lead to an amelioration, a lessening of the problem, if not eradication of HIV-AIDS.

FLATOW: Well, how can you test this out to know if it works?

WENDER: Well, we have worked our way through cells. We are working our way with animals right now. We are working with NIAID with samples that are taken from infected patients who have been on suppressive therapy. And in all of these cases, we are seeing very encouraging signs that these compounds are working the way we would hope they would work.

FLATOW: Doesn't cancer sort of hide a while after - maybe chemotherapy works but it comes back later? Would this work that way also?

WENDER: Exactly. I think latency is going to be a problem that we are going to have to put more resources on in the future. It's associated with cancer as you're indicating. It's, you know, a question of why can't we get rid of cancer? Why is it that we're only checking progression of the disease? There is a form of latency that we could think of in terms of - well, it's a controversial theory but it's stem-like cancer cells that might basically repopulate cancer after a round of chemotherapy, and latency is obviously associated with TB, it's associated with shingles, it's associated with many other types of diseases. So, learning more about latency could potentially not only be of value with respect to HIV-AIDS eradication but many, as you point out, many other diseases.

FLATOW: I'm Ira Flatow. This is SCIENCE FRIDAY from NPR. This library, how do you match up what you have in your arsenal and what might work to combat diseases?

WENDER: A lot of this is done through massive computer modeling. We try to understand how nature is using structure to generate information and how that information then can lead to changes with respect to diseases. But it's basically designed a knowledge of structure, a knowledge of function and putting it all together and creating planes by watching birds fly.

FLATOW: And how far along have you gotten on this?

WENDER: Well, we're dealing with information that ex-vivo now from patients, meaning that we're taking disease cells and tissue from patients. And we're making progress there. We're also doing work in the Alzheimer's area, basically using small molecules inspired by nature to do something that's pretty remarkable. And that is they induce the formation of new synapses in animals. And we think that this might be a way of dealing with a lot of problems associated with cognitive dysfunction, most significantly, obviously, Alzheimer's disease. We actually, there's a clinical trial that's been open, colleagues that I'm working with - Dan Alcott(ph), who's head of Blanchard Proctor Fill and Neurosciences Institute(ph), for example, is behind an organization that has now opened a clinical trial for possible testing of these contents.

FLATOW: Wow. Fascinating.

WENDER: I think so. Absolutely.

FLATOW: Just a long way to go, though, right?

WENDER: Oh, it is. It always is. The gestation period on a lot of these things will take time, but, you know, hopefully with enthusiasm and through the communication that you're kind of helping us all learn about these things, we will move along a lot faster.

FLATOW: Well, good luck to you, Dr. Wender.

WENDER: Thank you very much, Ira.

FLATOW: You're welcome. Paul Wender, Bergstrom Professor of Chemistry and professor of chemical and systems biology at Stanford. Transcript provided by NPR, Copyright NPR.