TWiV 1337: The whitefly and the Red Queen

0:00This Week in Virology, the podcast about viruses, the kind that make you sick.

0:10From Microbe TV, this is TWIV. This Week in Virology, episode 1337, recorded on July 3rd, 2026. I'm Vincent Racaniello, you're listening to the podcast all about viruses. Joining me today from Western Massachusetts, Alan Dove. Good to be here. And here in Western Mass, it is 96 Fahrenheit. That's 36 C. Humidity is only 37 percent, but it feels blazing hot. And we have an extreme heat warning going into the weekend, like pretty much half the country, I think. 38c here that's the peak today and the humidity is 41 which is not very high what did you say yours was 36 similar sorry 37 yeah so joining us from austin texas rich condit hey uh we're all doing the same thing here uh i got 96 degrees and uh 44 percent humidity 96 tears so you know if you look at the maps of this heat thing going on Austin has been pretty much normal while everybody else is getting in a relative sense clobbered but when you're getting clobbered and we're normal we're about the same yeah the difference is that Austin's actually built for that yeah it's like when we get an inch of snow and you get an inch of snow it's a very different experience yeah i was thinking i was thinking about this because i was thinking about air conditioning and uh i didn't live in a place with air conditioning until 1990 uh so i was uh 42 years old i in california uh san francisco bay area we didn't have air conditioning I'll bet you you do now.

2:19In Buffalo, we didn't have air conditioning, and there were times when we wanted it. But, you know, 85 degrees was sweltering at that point, at that time. And then I moved to Florida, and what a shock. It's very unusual for us to have the same weather as you. Yeah, right. Right. It's not infrequent, like in the depths of winter or whatever, that there's like a 40 degree difference. Even in the summer, we're not usually this hot. Yeah. This is unusual. If you enjoy these programs, we'd love your support. Go to microbe.tv slash contribute. We don't do ads on these programs. If you want to learn science, please help us out.

3:03There are a number of different ways you can do that over there. Don't forget the Rosenfeld Lab has moved to Philadelphia. They are recruiting a postdoc and a technician to work on enterovirus pathogenesis and immunobiology to understand the cross-reactive enterovirus antibody response, or I should say immune response, antibodies and T-cells, to make animal models for these viruses and to develop new vaccine platforms. You can email Amy at Rosenfelda at MLHS.org. coming up soon asv its annual meeting at the university of minnesota in minneapolis july 27th through 30th go to the website asv.org and click on asv 2026 on the top for more information the standard registration rates end on july 13th after that there's an additional charge so you should save money and do it now don't forget the asv social media video abstract competition you make a little video.

4:08All the instructions are there on the website as well. That deadline is July 13th. And ASV is also, the local hosts now are hosting, that's the University of Minnesota, the Viral Art Initiative. They're accepting submission of original artwork inspired by virology. And this will be showcased throughout the meeting. And again, check the program to see the details for that as well. So you could submit a video abstract of your work and an abstract video to the art competition. Indeed, you could. They should have a contest for clever podcast titles also. It wouldn't be a contest. We would have to recuse ourselves.

4:52Yes, exactly. Actually, we should think of some kind of a contest to do a title contest, right? don't we do that every episode but have our listeners do it because you know at the back of the New Yorker there are always these cartoons that don't have a caption and they say make your own and people do that so we can say well here here's a twiv make a title see if you can do better than Alan Dove that would be fun also so the meeting consists of morning symposia, which everyone goes to because there's only one session happening. And then in the afternoon, there are concurrent symposia. So if you look at the program, you can see that, decide what you're going to do.

5:40They're also, on the Monday before the meeting starts, in the morning, there are satellite symposia. And you have to pay for those. And you can add them now or later before the meeting. There are a number of different topics that you can go to. So check that out as well. I assume you found this new Zyna Malin. This is very interesting. Yes, I did. This showed up in my feeds. I was like, wait, they retracted what? So two papers from, I guess, let's see, it's more than a century ago, right? No, almost a century ago, were retracted by Springer Nature. And well, why are they retracting these old papers?

6:25And then you look at the author, the senior author on the papers, it's Max Planck. There's a constant named after this guy. There's an institute named after this guy. He's one of the most prominent and important physicists in history. And he had publications and Springer Nature retracted a couple of them. And not only retracted them, took them offline. So there's now a work by Max Planck that you can't download. And so this popped up, somebody who watches the retractions going on for the Retraction Watch website, or on the Retraction Watch website, saw this and said, wait a second, what? And it looked into it, and it looks like, and if you go to the link in this article, it's a science news story.

7:23It's pretty clear that Springer Nature had a bot go through their archive with a very simplistic list of criteria and say, just retract any papers that meet these criteria. and apparently they didn't like do any of this manually or put a past end date on it or anything or any of the normal precautions you should have. And it just seems to have done this. One of the papers had a title that was identical to the title of what he was responding to. And that was probably what triggered this retraction, which is idiotic. Springer Nature had no comment because I guess they don't want to admit that they screwed this up so badly It's what I find really interesting as they say, Plank was almost as widely revered for his character as his physics Yes He wouldn't do any of this stuff Why do they have to have a bot doing this?

8:23Do they have so many papers that people can't do it? They're getting rid of all their people so that they can have a fatter profit margin jeez i mean they barely employ editors anymore it's the copy editing has gone way down and yeah this uh picture of max plunk max plunk max plunk max plunk on the uh cover of this is very cool i like his um bow tie yes he's very he looks very serious yes he does yeah you don't want to mess with this guy no gosh i mean he's he's scowling at you yeah he's anticipating it because he heard about his papers being retracted retract his paper yeah gosh but so so they mentioned that he was critical of hitler and his son was actually involved in the attempted assassination and his son was executed yeah as a consequence yeah so very tragic yeah i hope they restore these papers because as someone says at the end, just put them back.

9:26Intellectually, it's not acceptable. It should be in the database. Thank gosh. Cool. Nice article. All right. So today we have something different for you. We have systems, one system we've never covered, I'm sure, and another we have covered, but not so often. So just because I felt like it, why not? And also So it's a holiday here in the U.S. I'm glad you felt like it because these papers are just really amusing. These are fascinating. Really good stuff. Yeah. And you should listen because, you know, these are not systems that we know ourselves. We can't know everything here on TWIV. And we can't even have enough hosts to know everything, you know.

10:15I've gotten some emails from people who say, you know, your knowledge of wildlife biology is a little shaky. Yes, of course it is. Yeah. But, you know, this is the nature of this program. You can't have an infinite number of hosts. You have certain numbers and you depend on their expertise and you depend on their being scientists. They could figure things out. Of course, there are details that we're not going to know, but you get the picture. And it's the nature of science that we never really understand what we're doing, right? I mean, because the whole point is to find new stuff. And when you find new stuff, you don't know what's going on.

10:58So yeah, each of us has expertise in particular areas, but then you get to hear us figure it out when we hit something like this. So this first paper is in Nature, Ecology, and Evolution, which is a journal I do follow because of TWIVO, but I think this may be the first use of the journal on TWIV. The title is, An Ancient Anthozoan Protein Reveals an Alternative Evolutionary Path of Antiviral Signaling. The lead author is Tan Sharoni, and the senior author is Yehu Moran. The crew is from the Hebrew University of Jerusalem, University of North Carolina at Charlotte, Kongju National University in Kongju, Republic of Korea, and the Ludwig Maximilians Universitat Munich, a very broadly distributed group.

11:50So an anthozoan, an ancient anthozoan. What is an anthozoan? These are organisms that are sessile. They sit on the floor. They're attached to something. They're typically marine invertebrates and brackish water also. Sea anemones, you might know. Stony corals, soft corals, sea pens. I like the sea pens. You can write with them. They're mostly attached to the seabed, but the larvae exist as zooplankton, right? They can swim around. So this is one of the three subphyla of the Cnidarians, which also include the jellyfish, the Medusazoa. And I didn't even know about the third one, the Endonidazoa, which are parasitic Cnidaria, the idea of parasitic jellyfish.

12:34And so Cnidaria is spelled C-N-I-D. And so just if you didn't know how to, you forget about the C. Yes. Just say Cnidaria. And so I was fascinated, first of all, because, well, there are viruses of everything, right? But we never talk about viruses of anemones. Sea anemones is what's the subject of this paper. And it's all about the innate immune system, which we've talked about a lot on TWIV in terms of the mammalian immune system. And just to remind you, the way it's triggered typically in a virus-infected cell is that cytosolic RNA is sensed by receptors. And these are the detectors of RNA.

13:18And they have helicase domains to bind RNA. And then they have what's called a CARD domain, a caspase activation and recruitment domain that will signal downstream to turn on interferon synthesis. My lab used to work on this many years ago. There are two of these receptors in the cytosol are called RIGI and MDA5. They sense and they bind viral RNA. That exposes the CARD domains. And then those CARD domains interact with a mitochondrial surface protein called MAVs, the mitochondrial antiviral signaling protein MAVs. And this binding leads to a change in the structure, which triggers phosphorylation of transcription factors that then go in the nucleus and turn on the synthesis of the interferon genes and the pro-inflammatory cytokines and so forth.

14:16All right, so that's the general pathway in mammals. In mammals, the MAVS adapter on the mitochondria is totally the molecular hub. It integrates the input from the activated, so these rig eyes and MDA5s are called rig eye-like receptors, RLRs. And the MAVs propagates the signal through into the activation of the transcription factor. And so because MAVs is so important, many viruses encode antagonists, typically proteins that cleave or proteolytically inactivate MAVs and disrupt signaling because they would rather not have an interferon response as well. These card domains in these proteins are not metazoans only.

15:05They have been found in bacteria, and they function in defense against bacteriophages as well. So how long has this been going on? That's the question. How long? The evolutionary origin of these pathways. So the early branching metazoa, like the nidaria, the corals, the hydroids, the jellyfish, the sea anemones, they give you a bridge to study the very, because they're still around and they're old, right, to study how old these things are, what they looked that. And what I didn't know is that the sea anemone, Nemestostella vectensis, is a model organism. You can genetically manipulate it. When I was reading the abstract of this paper, and I got to, you know, and then we did this and that, I was like, wait, you, what?

15:56You could do that with anemones? Yeah, I'm surprised that you can do it. I mean, these are the little guys. Actually, I didn't look up this particular species, but sea anemones in general, they're the things that clownfish hide in on the reef. They're all over the place. Yeah, this guy's a little different. Well, you can rear them in a laboratory basically in a petri dish. They're up to, they're two to four centimeters long, so this said. In terms of appearance, they are reminiscent of a hydra, which people may be familiar with. But Hydra are freshwater, and they're only about 10 millimeters long.

16:35But it's got this, it looks like a jellyfish with a long body and a whole bunch of tentacles coming out of it. So you can manipulate this organism and study innate immunity and antiviruses, antiviral evolution, because there are viruses, as you will see. Now, in the genome of N. vectensis, there are two paralogs of RIG-I-like receptors. They're called RLLA and B. They've been identified previously. They contribute to antiviral defense. And they're both induced transcriptionally. In other words, RNA is made encoding these. When you add poly-IC, which is a viral double-stranded RNA mimic, it's typically used in mammalian experiments, you add it to cells, and it turns on the synthesis of this pathway.

17:26And it also works in these sea anemones as well. Now, interestingly, so in the mammals, the RLRs bind RNA. But here, only RRB binds long double-stranded DNA. Sorry, RNA. If you add short 5' triphosphate double-stranded RNA, which will bind RIGI, It doesn't do anything from either RLRA or B. And so there's a difference between these receptors. RLLB, in fact, functions as a primary viral sensor. It binds long double-stranded RNA, which is what MDA5 does in vertebrates. And RLRA probably has a different role. We're going to see a little more about that today. It turns out that the genome of N-vectensis encodes many immune-related genes that have relationships to vertebrate counterparts, like C-gas sting signaling pathway, and apoptosis regulators are all there.

18:34So they're ancient, right? When you add Tali-IC to this sea anemone, you induce a very big antiviral transcriptional response. However, a MAVS ortholog has not been identified in the Nidarian genomes. So in this paper, what they want to do is distinguish between two scenarios about the evolution here, whether a true MAVS ortholog exists in nidarians, right? So maybe this is an ancient antiviral innovation, or whether nidarians evolved a parallel pathway that only partially mirrors what's happening in vertebrates. So we have the genome sequence of this C-anemone, and they find a gene that is a potential Mavs homolog, and it's got 33 % sequence identity with human MAVs.

19:37And its gene in the genome is right next to the gene for, this is in the sea anemone, RLRB. And the proteins have different structures. The vertebrate proteins, the MAVS proteins, have three domains. They have an N-terminal card domain, a C-terminal mitochondrial transmembrane domain, and then a 400 amino acid linker that gives you a flexibility for assembly on the mitochondrial surface. The one in the C anemone is smaller, only has a card domain. That's it, nothing else. So this genomic organization, we have the RLRB next, the gene for RLRB next. For some reason, it's hard to say RLR. We've got RLR and we have anemone in the same paper, yes.

20:35RLR is hard. So the RLR MAVS organization is actually conserved in all these anthozoan lineages. So there's probably something relevant about that. Okay, so now they want to look at the function of this gene. So this is the Mavs, punitive Mavs equivalent, right? So they knock it out, knock out the gene, and then they look at expression of immune-related genes under basal conditions, right? And when they take out this Mavs-like gene, you actually upregulate several immune-related genes rather than decrease it as you would in mammals. This is in basal levels without any stimulation. So it looks like it is repressing their transcription at basal levels in the absence of any stimulation.

21:28Then they overproduce the protein, the MAVs-like protein. They can inject embryos with a mRNA encoding the MAVs-like protein and M-Cherry. and then they can track M-cherry, which is fluorescent. Overproduction of MAVs led to a reduction, again, of immune-related proteins, including RLRB and Dicer and AGO, which are involved in small siRNA biogenesis. So even though this gene has some homology with MAVs, it has the opposite effect. It's a repressor of immune-related genes, whereas MAVs, of course, is an inducer. So based on that, they call it CARD inhibitor binding protein, or CARDIB. Or CARDIB, if you're a pop music fan.

22:30CARDIB? Is that something in pop music? That's a singer. CARDIB, really? CARDIB. Well, Cardib. Okay. So we know that MAVs binds the RIG-I-like receptors, right? That's essential for immune activation. So does that happen with these proteins in the sea anemone? So they predict the structures of these proteins using alpha-fold 2. And in fact, first thing they find is that there is no second card-like domain. There's just one, and so that's different from the mammalian proteins. Then they look at the effect of immune stimulation using single-cell RNA sequencing. So again, they have a C-anenomy cell line or a reporter line that makes M-Cherry under the control of the RLRB promoter, right?

23:32So the promoter is activated when you add double-stranded RNA. So they inject poly-IC into these animals, and they see that CARDIB and RLRB expression is stronger if you don't inject the poly-IC or if you inject them with sodium chloride compared with poly-IC injected animals. So again, the idea being that this is somehow a repressor of immune activation. Now, in mammals, the RIG-I-like receptors and MAVs physically interact. So they wanted to know if it happens here. They do a proximity ligation assay. They have antibodies against these proteins, and they can see if they're spatially close to one another by immunofluorescence.

24:27And in fact, they find close proximity between CARDIB and RLRB in the absence of poly-IC. But when you add poly-IC, they're no longer close to each other. So in the basal state, they're bound to each other, and somehow that is repressing these immune activations.

24:52And they also use alpha-2 to try and predict the structures of these two proteins, and they get good predictions that, in fact, they interact, which supports their proximal ligation assay results. All right, so basically what we've found so far is that CARDIB interacts with RLRB probably through the single CARD receptor. And it's a repressor of the immune response in the sea anemone. And importantly, that repressor is the opposite of what we would expect based on our studies of modern metazoans. Okay? We expect those, we expect MAVs, that is the, that's the CARDIP equivalent, right? To be activators.

25:54Right. So, you know, the downstream effect is the same, but the upstream mechanism is inverted. Of course, who came first? Yes. Well, that's a good question. Or maybe they came at the same time. I mean, is there a least common ancestor or a, what do you call it? The last, yeah. Last common? Last common ancestor. Because they talk about the bifurcation between these guys and others that are bilateral. Yes. And happening 650 million years ago. Yes. So there must be some critter that we can study from maybe? Well. Or these maybe not. Right. Well, you have bacteria, right? It's gone. Yeah, it's gone.

26:54Yeah, the common ancestor of us and Cnidarians isn't around anymore. Right. So looking at these Anthozoans is a way to drill back to that and say, okay, they've got this, we've got this, therefore that common ancestor must have had these ingredients, but probably wired in a different way. Right. Or maybe not wired at all yet, and that happened in both lineages, but opposite. Right. So they do a little phylogenetic analysis to try and understand how these nadarian cards relate to the broader metazoan card protein family. They have 1 ,055 sequences from six principal animal lineages. And they ask whether the C-anemone cards share ancestry with vertebrate immune receptors like RIG-I and MDA5 and MAVs, or are they a distinct lineage?

27:56And they look at it in two ways. They do a cluster analysis of the sequences, which is based on pairwise similarities of alignments. This puts the Naderian card sequences within the vertebrate maps group, okay? But when you use a phylogenetic reconstruction, where you build trees, positions them as a separate lineage. So the idea is that the Nidarian cards, they do have sequence similarity to the vertebrate Mavs, but they probably represent an independent diversification event. So convergent evolution, right, rather than orthology. It's kind of a little of both. Because, I mean, you go back to bacteria and they've got some of these components too, And then you get to this common ancestor of us and the Cnidarians.

28:55And it's got all of these components that we're going to use and it's going to use. And at some point after that divergence, so there was an evolution along that track and then the split and then a parallel evolution probably because of the viruses infecting them. but definitely because of the virus is infecting them that led to this separate development refinement the fact to me, maybe this is naive but the fact that in both the vertebrate lineage or the metazoan, I guess these guys are metazoans as well, in the vertebrate lineage and this anemone lineage, the fact that they're both tinkering with the antiviral response.

29:50I have a hard time not believing that the ancestor of both of these didn't use them in a similar fashion. Yeah, I think this is a refinement of an antiviral system that was there in the ancestor. And then it made sense to do this, but you could do it either way. Yeah.

30:13So they further push this analysis to see whether difference in selective pressures could account for these patterns. And they find that the CAR-DIB and the MAVS branches evolved under stronger purifying selection than the other CAR domains, so slower evolutionary rates. and also using a different model, they find that there's overall sequence conservation because of this purifying selection, but some of the sites in the protein still evolve under strong selection, which suggests an arms race with a pathogen, right, when you have individual residues that are changing quite a bit. As always. As always, absolutely.

30:57So to further understand this evolutionary relationship, They constructed a phylogeny of just the Naderian card domain sequences, right? And even though these CARDIB proteins are clearly divergent from canonical RLRs, their placement in this phylogeny is consistent with the idea that CARDIB may have originated through duplication of an ancestral card domain-containing gene, which is related to the RLRs, followed by then functional specialization, as we see here. Okay, now we're going to go back to some experiments. They want to look at the contribution of CARDIB to the immune response of this C anemone.

31:44So they have the two CARDIB knockout lines that we talked about. They also make knockouts for RLRA and RLRB, okay? And they notice when they're making these knockouts, they're growing them in the lab, they have problems. They have reduced growth. The adults are smaller. They have delayed sexual maturation. They don't feed very well. They die more often, right? So there's something wrong with... They didn't even have to take their anemones to the opera to see them. No, they have very avert phenotypes, right? So what they do is they take zygotes of both homozygous mutants and wild-type animals. They inject them with poly-IC, right, to stimulate these receptors and turn on the antiviral response or with sodium chloride as a control.

32:37And then they do transcriptome profiling. They sequence the RNA and you look at what's turned on. So CARDIB and RLLB mutants showed no response to poly-IC compared to wild-type animals. So they are clearly important for the response to double-stranded RNA. But if you knock out RLLB, RLRA, no problem. Pretty similar response to poly-IC. So a very different pattern from these proteins. Which at least, so based just on that lab experiment, you might say, well, RLRA does something different, or it's not as important, or they suggest maybe it's a fine-tuning knob. RLRB is where it's really at. Yeah, RLB and Cardib, right.

33:24So then they looked at some immune-related genes that are known previously to respond to polyic and also to viral RNA, to viral infection. It's been done before. So in the CARDIB and the RLRB mutants, there are no differences between animals injected with polyic or sodium chloride. So again, these are essential in mounting an antiviral response. And again, RLRA have expression patterns of these immune genes similar to wild-type animals, although a little bit reduced. So basically, CARDIB and RLRB are needed for initiation of the antiviral immune response in this C anemone and RLRA. I want to get, sorry.

34:11Yeah, RLRA, you take it away, you still have a response although it's a little bit reduced yeah go ahead so am i correct that in these knockouts there are there's a higher level of uh numerous immune response genes than in the normal animals consistent with these things uh being repressors it's correct it's a higher basal level i have to have to keep that in mind. Yep. And then when you add... I'm also keeping in mind that these guys struggled. They don't like not having these genes. Yeah, they struggled. That's right. All right, so next they want to look at viral load and apoptosis. So apoptosis is part of the defense against pathogens that would be triggered by sensing RNA.

35:12So apoptosis induction happens, as well as turning on all these immune-related genes. So they take a... I just got to... Sorry, I just got to pick out this, because this is appropriate. This sentence out of the discussion about apoptosis, it says, when a host is infected by a virus, one of the harshest tools available to the host to defend itself is the activation of apoptosis. I like that, too. I remember that. Yeah, harsh. It is harsh. Yeah. It's like, out of here. You're infected. Boom. Goodbye. So they're measuring viral load and apoptosis. So they take, they have, again, they're mutant animals and wild-type animals.

35:57They grow them for two weeks. They are in the lab, but they look at viruses that are present in laboratory cultures of this synonym. So they're already there, right, all the time. And so Cardib and RLR mutants, they have higher susceptibility to most of these viruses that are present in their cultures relative to wild-type animals. and the RLO, A mutants, similar viral load to wild-type animals. So if you take away RL, RB, or CARDIB, the viral loads go up. These are looking at the viruses that are always there in the cultures. So, of course, I was curious as to what these viruses are. Yes. There's a lot of them.

36:50They report on 1, 2, 3, 4, 5, 6, 7, 8 of them. but that's you know there's at least twice that many i think and i they have a they reference three different articles about this but i had a cursory look at those i want to see ems or something like that my guess is this is all sequence stuff yeah probably i don't know that they've actually isolated any viruses uh from these guys though maybe they have names do they have names uh not that i saw but i you know i just looked at abstracts and sort of skimmed through i I didn't look in any depth. I don't know if anybody's done a plaque assay on it. At least some of these are DNA viruses.

37:33Yes, that's correct. That's all I know. I'd like to know more. That's a fascinating topic.

37:42Okay. Now, this is a cool experiment. I want to look at susceptibility under natural conditions. I love this. They take these sea anemones in the lab and they transfer them to a mesocosm setup. It's like a realistic-ish environment. It's still controlled. You're not going to let predators get to them, but it's outdoors. It's outdoors. Is there any, yeah, so basically it's a setup which is basically exposed to native estuary water that's pumped from a lagoon where these anemones live normally. So they take that water and they're pumping it into this, they probably have a tank, I guess, right? And so the idea is they're pumping in viruses that are infecting these natural.

38:32Don't go swimming in the pool in this department. See anemones. This is at the Belbarouk Marine Field Laboratory in Georgetown, South Carolina. It's a nice summer project. And then they assess the viral load before and after this treatment by sequencing the viromes and doing viral read counts. So they have the wild type anemones and the mutants, okay? So they're putting them outside. So after this exposure, all the mutants had an Increase in viral load compared to wild type after 96 hours. It confirms that CARDIB and RLRA and B are important. And these communities, as Rich mentioned already, were dominated by double-stranded DNA viruses.

39:17And RLRA knockout was also affected. Yes. Which indicates, I mean, in the lab experiment, you say, oh, well, RLRA looks kind of dispensable. then you put them in an environment that's closer to the wild and oh, it's not dispensable at all now these get sick yep that's very cool it reminds me actually it's not dissimilar to a lot of other knockout animals that you make in immune functions of one sort or another they look non-essential until they're exposed to something closer to a natural condition and then all of a sudden they look important I don't know if you I don't remember doing this kind of an experiment with a mammal you take a mouse you don't put them outside and do this no you could have like an outdoor pen that's exposed to you know whatever is drifting around I don't know so I know what I'm thinking of I'm thinking of taking viral immune modulation genes and knocking them out and in culture not seeing a difference.

40:31But then you infect an animal. Yes. And all of a sudden those viruses don't do well. Okay? So it's maybe a bit of a stretch, but that's kind of like if the virus is an animal, taking it out of the laboratory and putting it into a natural situation. That is, in that case, an animal. Now I want to go back. We're talking about this. there was another sentence in here that i highlighted yeah um this is in the introduction uh uh they're talking about how mavs is a central role in the um this whole response it says because of the central role mavs is a common target of viral antagonism yes um you know sort of flipping that on its head, it reminds me of a student in Dick Moyer's lab from some time ago who was studying immune modulating genes and pox viruses.

41:32And he made the comment that these viruses have had millions of years to probe the immune system. And they had their finger on the pressure points of the immune system. So it makes sense to study what the viruses are doing because they know where the action is. They know the most efficient way to shut this stuff down. They don't know squat, actually. No. But they have evolved. They live or die. I mean, existing or not existing is a big selection pressure. Yeah. Depending on the conditions. Okay, so then they look at apoptosis, right? Which is a defense against, what is it, the most drastic, dramatic?

42:11What do they call it? The most severe? This is in the discussion. I'll find it. It's right here. The harshest tool available. Yes. Okay. So that's their harsh tool. They inject these mutant and wild-type animals with poly-IC, and then they measure apoptosis. Okay. Wild-type animals, they make a strong apoptotic response to poly-IC. The RLRA mutants have a weaker. So now we're back in the lab, okay? We're no longer in the mesocosm. What does mesocosm mean, Alan? I said it's a natural-ish environment. It's just a term for— It's like a microcosm is a little— Right, a microcosm is a little sample of something.

43:05I guess the cosmos would be the universe. a mesocosm is this in between thing that you put together. Macrocosm is big, right? Yeah, it's big. It can be, depending on the size of your organism, it could just be a few liters or it could be a swimming pool. But it's not the ocean. So they say it's a bridge between the highly controlled small-scale lab experiments and broader, less predictable field studies. Yeah, because if you release these things just in the Bay in South Carolina, you're never going to find them again. That's right. Or they're going to get eaten by something. Exactly right. Exactly right.

43:45Okay, so where was I? Apoptosis. Yeah, so basically the RLRA mutants have a weaker apoptotic response, but they still make it. And then the CARDIB and RLLB have no difference in the apoptotic response to poly-IC, right? So basically, loss of CARDIB or RLRB compromises the antiviral immune response, leads to increasing viral load, leads to impaired apoptosis, and removal of RLRA reduces the efficiency but doesn't abolish it. but in the field, RLRA is important, as we saw in a different result in the field. So that's the experiments. CARDIB, they find CARDIB. It looks like a MAVS ortholog, but it doesn't do the same thing.

44:43It's a repressor of immune signaling, although it's still important for sensing, right? But it is a negative regulator, and maybe this is so you keep immune responses down in the absence of infection, right? And that's conserved across evolution, that you have to regulate these kind of innate responses. And they call this a functional inversion of the gene, that during evolution this happens. And they say there's evidence that these card domains are really old in that they have been rewired repeatedly to do different things, which I think is cool. Yeah. Let's see.

45:28So RLB, as we said, binds long double-stranded RNA. RLLA does not, and that's what starts this all going. Yeah, and we still don't know quite what RLRA does, but we know that in the wild it's important. We don't know what RLRAA does. So that's the story. It's his balancing of activation and repressing. is old, goes back to the last common ancestor of the Naderia, and maybe much earlier in evolution as well. And that last common ancestor is nearly 650 million years ago. That's right. 650 million years of something. I had some titles here about that. 650 million years of antiviral signaling. Yeah.

46:14You know, I'd like to meet these guys, these people. They sound interesting. Which people? The Nadarians or the authors? The authors. I don't think the Nadarians would have much to say to us. No, they wouldn't. Although you have to ask the right questions like they did in this paper. Yes, actually they got a lot of information out of them. You know, this is why humans go to the moon or Mars. We're really curious. We want to know what's going on. this emphasizes you have to let scientists be curious let them do what they want if they have good training if they have a good environment if they write a good proposal let them do what they want because good things may happen you just never know right there's a editorial somewhere by some guy someone sent it to to us who says the NIH should be disbanded it's inefficient and politically driven and of no use whatsoever.

47:16And I'm just laughing like crazy. This is probably not NIH-funded, but, I mean, that's all about serendipity, folks. So this, actually, this is a bit of a sideline here, but reminds me of being on a study section. And I had the privilege at one point of being a chair of a study section where you get to say things that people have to listen to. and um i was always frustrated because i worked on pox viruses and smallpox wasn't around anymore by this notion that you had to justify everything in terms of curing a disease yes or something like that and i would also get frustrated reading grants that went through this you know big spiel about how they were going to cure some kind of disease when i know for certain that the author has no interest in that okay they're just screwing around right so i was really uh taken by uh grants that started off and said look this really weird thing is really interesting and that's what we're interested in.

48:34Oh, by the way, maybe it'll have some practical impact someday. Okay? Tell me your truth, okay? Don't try and BS me because I'm not buying it. And don't waste my time. I don't want to read through all that crap. In later years, they made you write impact and significance into the grant, which I just never liked. No. Come on. Just tell me why it's really fascinating to do this. That's all. So this guy who is against the NIH says it all should be done in the private sector. Can you imagine this being done? No company would do this because there's no product. No, doing it all in the private sector would last for a few years until they ran out of basic science to apply, and then you got nothing.

49:22Yeah. Okay. Second paper is also very interesting. thing. This is in the Proceedings of the National Academy of Sciences, or PNAS, as we used to fondly call it. We still do. And these papers, by the way, PNAS has different divisions. We have a microbiology division. This division is Agricultural Sciences, a bacterial symbiont, and a plant virus walk into a fungus, enhance insect fitness by inducing physical defenses against fungal parasites. First author is Tianyu Wang, and the senior author is Junbo Luan, and they are from, scrolling to page 11, I think it was. Thanks, PNAS.

50:16Shenyang Agricultural University in Shenyang, China, Chinese Academy of Sciences in Shanghai, and Dalian University of Technology in Dalian. I have learned over time. My method for reading papers is still evolving. Okay, but I have learned over time, in particular with TWIV. After I maybe look at the abstract or something like that, I will scan through the paper to look and see what the figures look like. You know, at first, to kind of inoculate myself, say, okay, this is what I'm confronting. But in the back of my mind, as applies to this paper, I have also learned that people often put what is effectively a graphical abstract as the last figure.

51:04Yes. And, you know, you wade through all this stuff trying to imagine what's going on. And then you get to this, you say, why didn't you tell me up front? Yes. So, but that applies to this paper. Okay. I had the wisdom to go through and the last figure is a graphical abstract that really lays it all out.

51:26So, what was I going to say? Walk into a bar? No. So, oh, I said, I was going to say, so, you know, we know all about beneficial microbes. We've talked about beneficial viruses, but this paper is interesting because we have two beneficial microbes. We have a virus and a bacterium or a virus and a rickettsia. And it just shows that, you know, because animals and plants have a lot of different microbes in them. More than one can be beneficial and help each other. And the host that they're benefiting is an insect. Right. And the parasite that they're helping the insect with is a fungus. It's a fungus.

52:09We've got everything here. So we have fungus, rickettsia, insects, and viruses. Not only that, but the virus is a plant virus that's in the insect. Like what? Yep. Yes. Yes. Plant virus in the insect. Right. So we have to talk a little bit about the cuticle, right? It's a first barrier of defense, which prevent pathogens from entering animals and plants. And there's some evidence that the cuticle can be improved by immune responses, but also by modification of the cuticle by other mechanisms. And that's what this paper explores. The cuticle is a cross-linked matrix of proteins and chitin. And this you will see is part of the story here.

52:58And now one of the players in this paper is the white fly. It's an insect. And they can have all kinds of microbes. Which is in the order Hemiptera, not Diptera. So it's actually a bug, not a fly. A bug? It's called a white fly. It's a white fly. Is it an insect? It's not an insect? It's an insect. Yeah, it's an insect. It's in the order of true bugs, as entomologists say. And it is a major, major agricultural pest worldwide. It has spread over the years. It's pretty much around the subtropics. Yeah, it's very interesting. So it's a pest, but in this paper, we're going to see how it's protected.

53:35We're going to be on its side. Yeah, we're going to be on its side, which may be a little confusing. And microbes have been shown to assist cuticle synthesis. So bacteria in particular can provide tyrosine or its precursors. And this has been found in beetles, weevils, ants, stink bugs, and white flies. And so here they want to ask whether different microbes, including viruses, can also do something with cuticle and basically give protection to the host against the natural enemy. All right. So then white flies are one of the players today. These are pests, as Alan said, big crop losses. They cause crop loss by eating and also by transmitting viruses.

54:24And the viruses include begomot viruses, begomot, which are over 200, and they can be transmitted by these white flies. And they can be transmitted horizontally and also trans-orvarian as well. So the white flies, Bermesia tabaci, and it's called M-E-D and M-E-A-M-I, okay? And then we have these Bermesia white flies. They harbor symbionts, obligate symbionts as well. They have Quartiera and Hamiltonella and Riccatsia, okay? in bacteria sites because rickettsia have to live within another cell so they're living within what's called a bacteria site in the white flock rickettsia are kind of sort of bacteria yeah but they have to live intracellularly they don't live on their own they don't have cell walls or do they that's a good question let's look it up I you know I was never any good at the bacterial side of things.

55:42They're gram negatives, and they have a typical cell wall, which has peptidoglycan and lipopolysaccharide. Okay. Yeah. Okay, so back to the story here. Some of my old micro-friends out there are rolling their eyes. That you didn't know that? Yeah, kind of didn't really. They have a cell wall. So the fly has these symbionts. You've never heard of Portiera or Hamiltonella, but you've heard of rickettsia. And these are within the cells in the white fly. And these have been found in white fly populations in the U.S. and in China as well. The rickettsia confers fitness benefits. and a female bias as well.

56:34So it leads to spreading of rickettsia in the white fly populations when they're present. Now, the other player is entomopathogenic fungi that are pathogenic for insects, right? They actually regulate insect populations in nature, these fungi. And mycoinsecticides have been used to control white flies, controlling it with this fungus. So the whitefly microbe associations are nice systems to investigate the effect of multiple microbes because we have a couple here. All right. So previous result, if you feed tomato yellow leaf curl, China virus infected tobacco plants, viruliferous white flies, you get higher trihalose expression and trihalase activity.

57:28Sorry, Bttrez expression. That's a gene that's involved in trihalase expression or trihalose. Trihalose. Trihalose. Yeah, so you're feeding this infected tobacco plant to a virally infected, a viruliferous bug. Whitefly, yeah. and you get higher trihalase activity and lower trihalase contract. And trihalase, trihalose, excuse me, is a precursor for the insect cuticle chitin synthesis. And so they're thinking that begomoviruses, of which this tomato yellow leaf is one, may impact the chitin content of white flies. They've also shown, and this is a different story here, so the virus can somehow maybe induce chitin synthesis.

58:25Then you have, there is one of the gene, tyrosine B is missing from Gortiera, one of these other symbionts of the white flies, for the synthesis of phenylalanine, TYRB. And there's evidence that the Vickettsia genome provides that. because the Rickettsia genome has the tier B and also a PHH phenylalanine A synthase gene. So the two bacteria that are symbionts need to collaborate to get this amino acid made. Yes, and they are helping the whitefly, because the whitefly, so, sorry, Portiera doesn't have the gene that's needed for this synthesis. So basically, there's a lot of stuff, interactions going on here, and they want to, their idea is that begomoviruses and rickettsia could influence cuticle formation of white flies and impact their sensitivity to fungal infection.

59:27And they're really curious, they're curious about this on two levels. One, this is an important crop pest and they'd like to understand what's going on and why it is or is not susceptible to the fungal pesticides people are using. And two, as they point out, this is a great system for studying multi-symbiont interactions because most of literature on symbiosis is one symbiont and one host. And you get these just-so stories about how the bacteria help the termites digest wood or whatever, which is interesting, but there's more going on in nature. And so this is a system to look at one of these multi-components.

1:00:05I had two other background questions that I will reveal here about the virus. So begomovirus is a naked capsid plant virus, but it's weird because the capsid is a twinned capsid. It looks like two icosahedral capsids that are like Siamese twins. They're stuck together. And those capsules together contain a bipartite that is two single-stranded DNA circles that together comprise all the genes you need to make this happen. So that's just sort of structural background. And then I wondered, does this thing actually replicate in insects? Because there's a couple of different kinds of vectoring in the viral world.

1:00:58One is just a mechanical vector where whatever the vector is just picks up some of this stuff and transmits it. And the other is what I might call an active vector where the virus can actually replicate not only in its end host but its intermediate host, the vector. And it turns out that these viruses can actually replicate in the insect host. That was a new one to me.

1:01:26All right. So first they do some field studies to try and make correlations between the virus, the rickettsia, and the fungi in the whitefly. Okay. So what they do is they monitor the dynamics of these virus, the bacteria, the fungi in whitefly populations at a bunch of sites in China. Okay, in 2022, 2023, and 2024. And this is really, there are a lot of words here. Let me see if I can, I mean, you know, they take samples and they look for white flies. They look to see whether they have the portiera and the rickettsia, for example. All the white fly samples were positive for portiera. And what they do is they extract DNA and they sequence it.

1:02:21They can tell what's present there. The rickettsia were found in 80-some percent of white-fly adults. The virus, tomato yellow leaf curl, was found in over 95 percent of these begomovirus-infected adults. And then they find six species from four parasitic fungal genera. We don't need to know the names of them. They're identified in the adults as well. And the incidence of big homovirus in female adult white flies increased from 22 % to 40 % in 2022 to 23. Then it went back down again. And in the same time, the incidence of verketia went up and then decreased later. So they're trying to make parallels between these.

1:03:16That's a really good field study. Yeah. You know, take a natural situation, start off with, is this really relevant out there in the wild? And then the fungal infection decreases from 14 % in 2022 to 7 % in 2024 as the increase in rickettsia, right? So that's suggesting that they're related. The infection by rickettsia or virus had a negative correlation with infection by the parasitic fungi in adult whiteflies. That's the bottom line from all of that. So if you've got the rickettsia or the virus, you're less likely to get the fungus, maybe. Yep. By the way, I suppose this comes out of this, maybe this is obvious, but it comes to me out of this final graphical abstract image.

1:04:04When the fungus infects the insect, part of that infection is to penetrate the cuticle. That's right. So how sturdy the cuticle is has an impact on that pathogenesis. Yeah, this is not an orally spread or inhaled fungus. This is something that eats into the insect to get in. Right. So if you make a better cuticle, you can be more resistant to the fungus. Armor. All right, so now we go back in the lab, or we go to the lab, and we want to know if the virus and Rickettsia impact fungal infection in the laboratory. So they have, they're going to measure the fungus over two to five generations of white flies that are reared on tomato plants, right?

1:04:51So they have equal numbers of either non-infected or TYLCV, right? Tomato yellow leaf curl virus, right? Infected white fly adults with or without rickettsia. And these are released on plants in the same cage and then inoculated with the spore suspension of the fungus, right? Some experiment. Isn't that amazing? So the first assay, all the white flies don't have rickettsia. The white flies don't do well after exposure to the fungi. They only last one generation because they don't have the rickettsia, right? In contrast, the proportion of viruliferous white flies without rickettsia and not infected by fungi increases over two generations.

1:05:38So the virus makes them live longer. Fungal load is lower in viruliferous whiteflies than in non-viruliferous whiteflies across two generations. Okay. Then they have a second experiment where all the whiteflies have rickettsia. There, the whiteflies live a long time, but they go four generations. And the proportion of viruliferous whiteflies infected by the fungus is lower than that of non-viruliferous white flies over four generations. That's a nice figure that you can see all of this stuff. The fungal load is lower in viruliferous white flies than in non-viruliferous white flies over four generations.

1:06:23Okay, so that's that. So viral infection rate remains stable and the fungal infection rate goes down. They have a... Picture here, a photograph of a fungus-infected whitefly. Bad news for the whitefly. I'll say. I can't see the whitefly. All I can see is fungus. Yes. Nature is tough. It's hard. Nature doesn't care. No, they don't care. It's just all evolution. Nature wins either way. Yeah. I mean, humans should know better. We screw up left and right, but we should know better. Yeah, we should know better. Can I quote you on that? Maybe that's a show title. We should know better. Humans should know better.

1:07:08You know, the two people climbed to the top of the Empire State Building the other day. Did you hear about that? Oh, yeah. Which is just a few blocks from here. Right. They went all the way to the top, and they held up a thing that says, when the power of love exceeds the love of power, then we will have peace. They brought this big banner up with them. And they were arrested, and they're going to be charged with a million different things. Well, among other things, that tower apparently puts off so much electromagnetic radiation that there were health risks going on. And they had to shut down a bunch of transmissions.

1:07:46All those guys were up there. It's a major radio tower for the city, and there are gigawatts of RF going through it. And you could literally microwave yourself by climbing on those towers. But I really like their message. I like the message. Yes, nice message. I feel bad that they have to be charged with 15 different things. I understand you have to follow the law. You can't encourage that sort of thing. Otherwise, you'd be scraping people off the sidewalk every day. Yeah, but, you know. Or off the end of the house. They still got their message across, okay? Anyway, humans should know better. Humans should know better.

1:08:24That's what I was going to ask. Nature doesn't give a damn. It's just evolving. Yes, that's right. Okay, so back to rickettsia, the effects of rickettsia on the dynamics of fungal infection. The proportion of rickettsia-infected white flies infected by fungus was lower than the white flies without rickettsia over four generations. So rickettsia alone can't protect against fungi, but the virus provides an additional benefit. And, you know, in nature, a little bit makes a big difference. Yes. Can make a big difference. Okay. So then, let's see. They want to know the effect of the virus and rickettsia on whitefly fecundity and mortality after fungus infection.

1:09:18So fecundity is like how many offspring you have, right? So the virus did not alter the fecundity of white flies with or without rickettsia on the tomato. The virus did not change the fecundia with rickettsia, but it increased the fecundity by 50 % in white flies without rickettsia on cotton, which is not the natural host of this virus. Infection by rickettsia increased fecundity by 142 % of non-viruliferous and 141 % of viruliferous whitefly. So rickettsia is doing a lot on its own. And by 239 % of non-viruliferous and 172 % of viruliferous whitefly. So rickettsia has a bigger effect on whitefly fecundity than viruses.

1:10:09Interesting, rickettsia increases the acquisition of virus and the transmission of the virus. This is so mind-blowing, right, that a rickettsia can affect transmission of viruses. This is such complicated interactions. Then they want to know the effect of the virus and rickettsia on the defense of the whitefly against fungal infection. So they have these three parasitic fungal species, and they look at mortality, and they see that if you have rickettsia there, you decrease the mortality of the white fly after you expose them to these fungi. If they don't have rickettsia, they die at a high rate.

1:10:50Excuse me, but I'm trying to think about what selection pressures there are going on there. with the rickettsia motivating, if you like, the uptake or persistence of the virus. Who's doing that? Is the virus tricking the rickettsia? It benefits everybody involved, right? Obviously, the virus gets around better. The rickettsia are preserving their host. The host survives. So everybody but the plant is coming out ahead in this. But does the virus – the virus doesn't necessarily confer any – oh, it does confer an advantage to the insect. It does confer some benefits. That's right. Not as much as the rickettsia, but it's – Because it protects it from the fungus.

1:11:41Yeah. I'm good. But that's good for the virus too, right? Yeah. Because it's helping it transmit in the whitefly. Absolutely. It's not good for the plant, as we know, but – And God knows what else these critters are doing, right? Yeah, of course. This is just one scene. Also, there could be other players that we don't know about, right? All right, so the virus and rickensia confer protection against fungi, pathogenic fungi and white flies. All of this data, the field data, the experimental data, that's what it shows. How does it do this? The molecular mechanism. How does it promote resistance?

1:12:16So they look at eight genes that are involved in chitin synthesis by RT-PCR. And so they have two genes, BT-Tree1 and BT-CHS. So BT-Tree1, I think, is in trihalose synthesis. Right. And the other is chitin synthesis, the BT-CHS. These are upregulated in viruliferous whiteflies by 139 and 19 % at three days after virus and then higher, different at 10 days. So these genes are induced by virus infection that are leading to the synthesis of chitin. So as they say, they play important roles in chitin synthesis in the insect cuticle. And so the virus could impact the cuticle. And they measure that.

1:13:08The chitin contact goes up by 56 % and 99 % after virus acquisition in viruliferous flies compared to non-viruliferous. They do transmission electron microscopy. They can count the chitin layers in the white fly. And the cuticle thickness increases by 38 % when the virus is there. They upgraded their armor. Upgraded their armor. You can't make this stuff up. No. Then they silence these genes by siRNA. A. So they have white flies that have rickettsia in them, and then they silence these trihalosin chitin synthase genes. And this reduces the chitin content. It reduces the number of layers of chitin.

1:14:02It reduces the cuticle thickness. They also use a TRI-1 inhibitor just for a different approach. It's called validomycin A, and that also decreases the chitin content and number of layers and the thickness and all of that. So basically the virus improves the armor of the fly by promoting chitin, cuticular chitin generation by upregulating the expression of these genes that are involved in chitin biosynthesis. It's amazing. I'd like to know how it does that. Yes. We're not going to know in this paper. No, we're not going to know in this paper. That's enough for one paper. Yeah. So that's one thing.

1:14:49That's the virus. What about Rickettsia? What does it do? So remember, they want to know. Rickettsia can help with Portiera, the other symbiont, in the synthesis of phenylalanine, which you need to make chitin. And so they predict the stroke. So the genes involved are TYRB and GOT2. So the Rickettsia is TYRB, and then BT is, what is BT again? I forgot what BT is. GOT2, these form a homodimer, and they have a shared catalytic capacity for phenylalanine synthesis. They make the recombinant enzymes in E. coli. They show that TYRB catalyzes the synthesis of phenylalanine in vitro. And it also does also BGOT2, but the TYRB is better at it.

1:15:50And then the phi-tyrosine and dihydroxyphenylalanine contents that they've made here in these reactions are subsequently determined in female adult flies with or without rickettsia infections, without virus, the contents of phi, tyrosine, dopa, they go up in rickettsia-inflected white flies compared to non-infected white flies. And three cuticle protein genes also go up in rickettsia-infected white flies, and the cuticle thickness increases. So basically, these, excuse me, the complementation of these genes is resulting in the synthesis of phi, tyrosine, dopa, which increases the cuticle size.

1:16:39They also silence these genes in flies by siRNA. And they show that this decreases the cuticle size, right, as you might expect. Phenylalanine content goes down, and the cuticle size goes down by transmission. So Rickettsia facilitates cuticle formation by cooperating with Portiera for the synthesis of phenylalanine, which then turns on the cuticle synthesis genes. Yeah, this is amazing, right? Yeah. We're almost done. Two more experiments. So the cuticles, as you may have gathered, are rich in chitin and proteins. And insect pathogens often have chitinases and proteases to degrade the cuticle so they can infect.

1:17:34So the virus that we've been talking about increases chitin synthesis. Rickettsia facilitates protein synthesis in the cuticle. And so they want to know which chitinases and proteases of the fungus are involved in penetrating the cuticles. As Rich said, you know, the fungus penetrates through the cuticle. So they do RNA-seq of viruliferous and non-viruliferous flies with Rickettsia after fungal challenge. And they can see chitinase gene expression. So a putative chitinase is differentially expressed in viruliferous white flies compared to non-viruliferous white flies. And there is a serine protease gene that is differentially expressed in the rickettsia infected white flies.

1:18:26And so what are these two genes doing in fungus infection? So they delete them. They do deletions, complementations, and overexpressions. And so the deletions, this is in the fungus now, so they're deleting these genes, the chitinase and the protease genes. And if you delete them from the fungus, they can't infect white flies anymore. So it shows that they're important for infecting the white flies. If you overexpress the chitinases and the protease, the white flies don't do well either, which we would expect from that as well. And so these chitinases and proteases are important for the fungus to get into the...

1:19:15The bug. The bug, sorry, the white fly. And that's why the Rickettsia and the virus increase the amount of chitin so that it's protected against this stuff, right? So then finally they find that the core chitinase and protease genes are required in the fungus to infect white flies. That's a summary, actually. All right. And finally, last experiment, they want to see, they want to repress the cuticle synthesis. So they make RNAi that's going to repress the trihalose and the cuticle, the CHS again. I already forgot. CHS. Oh, yeah. So many abbreviations. Chitin. Chitin synthase. Synthase. Okay. So the trihalose synthase and the chitin synthase, they're going to knock them down by RNAi.

1:20:13When you challenge the flies with, so they're being knocked down in the fly. When you challenge the flies with fungus, they die. They don't like not having these trihalose and chitin synthase genes. Their mortality increases. And they also silence the TYRB in female adults by microinjection, and the mortality goes up. So it looks very clear that both the virus and the rickettsia protect the white flies against the fungus. The mechanism involves making a thicker cuticle in the white fly, which both the virus and the rickettsia do. So this is a lovely study where they do the field study and they get evidence that this tripartite thing is important.

1:20:56And then they go in the lab and they figure out the mechanism. Yeah. It's pretty cool, right? Great stuff. And the significance here is there's not just one microbe that's doing this. There's a collaboration between two, more than two, actually. Really three, because there's the, what is it? Portia, yeah. Portiera? Portiera. Portiera. And so this is defensive symbiosis, right? Yes. It's not providing a nutrient, which is another kind of symbiosis, but this is providing defense. It's like medieval stuff, you know? Yes. Hire me to provide defense from... Hire an armorer. And this time we're getting a virus and a rickettsia to do this.

1:21:38So they say in their conclusion, this study suggests that microbes residing within insect hosts should be considered when deploying natural enemies for pest biological control. Furthermore, defensive microbes can be engineered and harnessed to manage agricultural and vector-borne diseases. So it's interesting. If you want to get rid of the white flies, you could interfere with this cuticle upregulation, right, in some way. Especially since this fungus is an insecticide that's actually used. Yes. Yeah, so if you use the fungus as an insecticide, that might motivate, in air quotes, the insects to pick up or populate, maintain better populations of virus.

1:22:29That could have a downstream negative effect because they're vectors for the virus. Yep, that's right. It's complicated. Yep, nature is complicated. It's not nice to fool Mother Nature. But this is fascinating because there's so many things. You get the basic science out of this, and then you get potential for control. And you realize that this is a simple couple-organism interaction, but there's many more there. I mean, what's going on? Yeah, it's complicated. Anyway, that's that. let's do a couple of emails

1:23:13yeah this is not bad that first one Alan can you do that yeah this goes on for a while so I may accelerate through some parts of this Lana greetings from Edmonton Alberta currently 13C and a common theme in your episodes with Angela and Daniel that comes up from time to time is how to endure cold temperatures and goes on to discuss having been born in a city northeast of Saskatoon, Saskatchewan, during late November. When I was a child, temperatures were regularly plunged down to about minus 40 C, which is also minus 40 Fahrenheit in the winter, and stay there for a week or 10 days. Let's see.

1:23:57The Norwegian expression. Yeah. I've heard the Norwegian expression, there's no bad weather, only bad clothing, and find this to be true, at least during a Canadian winter. Living comfortably through a long, cold winter is not possible without at least one down-filled parka. They're expensive, but if you take good care of them, they're going to last for a long time. And she talks about some of the characteristics. The zipper should be sturdy, and there should be a flap over the zipper so wind doesn't go through it. I still have my buffalo down-filled jacket. I have what I call my space suit. I've got a down parka with exactly these types of features.

1:24:38Don't skimp on the quality. It's a lot of money up front, but she's had one more than 15 years before replacement. And the most economical time to buy a new parka is when they start to go on clearance around late January, but start checking around Christmas. Especially true, the price drop for kids' clothing. And pick up extra kids' mittens on clearance there, too. Yes, very, very good idea. Let's see. For adults, I recommend merino leggings or underwear, merino wool, under the pants when it gets cold. Wool is much better than synthetics. More expensive, but it's durable. Alpaca is even warmer than wool.

1:25:22Well, alpaca is a wool, but it's made from alpacas. It's a hollow fiber, but it's less body and tends to droop. So I would recommend 50 % wool, 50 % alpaca. wool socks, good quality boots with a grip, and get good quality of those as well. You may actually need to search around for good wool accessories. It helps to know a knitter or take up knitting yourself. In Saskatoon, you can go to stores along Broadway Avenue to find good quality knit items, or probably the farmer's market. You need a variety of hats, scarves, at least one good pair of thick wool mittens, and let's see for temperatures below about minus 30 C minus 22 Fahrenheit or less if there is a wind or you can expect to be out for some time consider using a Swedish walking skirt over your clothes they're expensive but available in Saskatoon sounds like go to Saskatoon to get your winter clothing and provides a link to these it's basically a wraparound blanket for your legs so let's see talks about fitting the Swedish skirt and you also need to account for being out for longer or shorter duration, going between inside and outside your expected activity level and changing weather conditions at University of Saskatchewan I believe that they used to offer a crash course for international students on how to dress for winter I'm not sure that's something they still do That's a good idea.

1:27:03That is a very good idea. The symbol on old Norwegian Scandinavian calendar sticks, primstuv, was a mitten for late fall. October 14th is now known as Mitten Day, and is the day traditionally you take out and ready all the woolly winter items for winter. It provides a link. My point of including this tidbit, apart from being interesting, is that preparing winter clothing, especially for a family, takes dedication and planning. So it's usually washes and dries and repairs and just takes a general inventory. Items we no longer use are washed and dried and put away for donation when the next cold weather approaches.

1:27:41I could go on, but just want to add that I do wear contact lenses in cold weather and they should never freeze. Yes, sometimes I do have frozen drops of water on my eyelashes. However, if your contact lenses are freezing, you likely don't have enough insulation around your face. There are wool balaclavas and parka hoods with fake or real fur that can trap some heat near the face. Parka hoods with fur around them have the added bonus of catching snowflakes and keeping them away from your face. Be sure when driving on the highway during the winter you bring along a heavy coat, winter accessories, and everything you would need to stay comfortable for a few hours while waiting.

1:28:19That's necessary even with cell phones because there can be gaps in coverage. and a driver that has slid into a ditch could be waiting for help for quite some time, although people in rural Saskatchewan in particular tend to be very helpful and resourceful. As proof that a person can survive and thrive in winter weather, I offer this photo taken during a walk for groceries on a Saturday in January when it was about minus 20 C, minus 4 Fahrenheit. I was listening to Twiv at the time. Yes, my hat doesn't quite match with my mid-range winter coat, but that hardly matters at that temperature. Not many people were out walking.

1:28:50I was perfectly content and comfortable. Thank you all at MicrobeTV for your contributions to science communication. Your work is engaging, approachable, and I always learn something when I listen. I am one of the science people that you picked up as a listener during the pandemic, and I haven't stopped listening. If anything, I'm just slightly disappointed that it is too late for me to pursue a career in virology. Hopefully this email can be a sort of resource for people in the MicrobeTV community that need to adapt themselves to life in a cold climate. Sorry it's so long. Should I make a tip sheet before next winter arrives in the northern hemisphere?

1:29:21I think that would be a great idea. And Lana is a chemist. Thank you very much, Lana. So if you want to read the whole letter, it will be in the show notes. It will be in the show notes. It will be linked. But this is great. Yeah. Thank you so much. So I grew up in California. It wouldn't freeze occasionally. But that was a big deal to go out and smash through the thin ice on the puddles. Okay. and then I moved to Connecticut for graduate school and I will never forget the day that I got up and took a shower and went outside to wait for the bus and my hair froze. I was shocked. What? This can happen?

1:30:02And then you get to the nose hair freezing weather. Where you walk out and inhale and what's it? Oh, my nose hair is just frozen. Then I moved to Buffalo. How cold would it get in Buffalo? Not that cold. It would occasionally go down to zero Fahrenheit, maybe a little bit below. And actually, it would stay well below freezing for days. By then, I had a beard, and I walked to work. So when I got to work, my whole beard was frosted up. I had to thaw out every time. then of course I had the experience of when when you're in Buffalo I gotta get this right when you're in Buffalo and you wear glasses and you're outside you go inside your glasses fog up then I moved to Florida okay you're inside in the air conditioning you go outside in the humidity and your glasses fog first time that happened to me I said wait a minute this is backwards this is backwards I'm going to take the next one, Rich, because I know you don't like reading long letters.

1:31:11Thank you. It's from Mike. Your recent discussions about the attack on science by the current administration has caused some cognitive connections to go off in my head. Governments and corporations periodically purge their ranks of scientists or intellectuals of some stripe. This phenomenon has precedence. One obvious example was the way Hitler's Germany, by being not at all subtle about their hatred of Jews, caused the diaspora of Jewish scientists, specifically physicists, to flee Germany before Nazi control could bring the Holocaust to bear. We owe part of our victory in World War II, as well as our political and scientific domination in the world since World War II to this effect.

1:31:53The U.S. was the recipient of this brain drain, which resulted in the Manhattan Project and the development of nuclear weapons. There is also a corollary with rocket scientists in our space program. In that case, it was more like a race for these scientists to be captured by Americans rather than Russians, but still a brain drain of sorts. There's also a corollary of the business world, where financial types buy and sell companies like kids trading Pokemon cards with no real understanding of what they have purchased. Then they employ the MBA handbook on managing these companies to maximize short-term profits.

1:32:29What is the R &D department doing? Their costs cut into our profits. They must all go. This trend of zeroing spending out on research in the corporate world has been accelerating in recent years. The most knowledgeable people about their company's technology are shown the door because they did not fit neatly into some financial wizard's spreadsheet. I call it throwing your brains out on the street. Fiduciary responsibility is a term these finance bros throw around, which means you have a legal responsibility to only focus on profits, always quarterly or similarly short-term profits, over the long-term growth trajectory of a company.

1:33:09These companies are bled dry and wrung out financially, then discarded once they are no longer viable profit-generating engines. These finance and tech bros have co-opted our government and are now applying these short-term finance-boosting algorithms to our American experiment. They cannot understand how research takes time and inevitably uncovers whole bodies of scientific discovery that may not have been intended or imagined at the offset. Just what we were saying before. Yeah, appropriate for this show. Investing in long-term research is both a matter of faith and a method with a long-term track record of success.

1:33:45We live in an era where our current crop of government leaders would rather take immediate profits than to ensure the future success of the country. We have seen this coming for decades now with the response to climate change. Corporate interests see doing anything about climate change as disrupting the well-oiled profit machine that those with wealth have depended on. They fear that any regulatory response would cripple their formula for getting rich. So they invested in media companies that would counter that message, and they bought politicians that would go to Washington and dutifully vote for the interests of the wealthy entrenched interests.

1:34:22What we see today is a result of this movement. What it will result in is what it always results in, brain drain or more academic sounding human capital flight. You've mentioned it yourself on many of the microbe TV shows. Scientists will leave America to go somewhere that will support their research efforts. China understands this and is quickly making the move to support research and secure the best minds in the world. For decades, the research grant system in the U.S. ensured that the brightest minds would come here and be able to indulge their curiosity in what could be described as the most wonderful playground for the mind that humanity has ever seen.

1:35:03This is what helped make us exceptional. Not some gun-toting, freedom-loving, militaristic independence streak. It was our ingenuity that put us on top and our desire to share those methods with like-minded allies so that the rising tide could float all ships. Oh my gosh, this is great. Yeah, very good. My grandfather used to say, get a good education. They can't take that away from you. His context was when communism was on the rise and anyone of wealth in those countries were stripped of their financial holdings. Their wealth was redistributed in theory to their fellow citizens, but in practice to corrupt oligarchs.

1:35:42My grandfather's point was that if you're educated and trained, those skills are portable. They can strip you of all your earthly possessions. They can drive you out of a corporation or a country, but they can't remove your ability to figure things out. They can't take the experience and knowledge in your head away from you. You can always move on to a new place and rebuild because you have the blueprint of how to do it in your head. Human capital is portable. One digression from this point, I fear how AI is being brought to bear in society. In theory, a highly intelligent computer could be directed by a human researcher and made to greatly accelerate the learning curve of discovery.

1:36:24In practice, this technology is in the hands of a small number of tech bros, who I fear are going to use it to control the population and harvest all the ideas and fruits of their labor for themselves. This is why kleptocracies always fail. At some point, the masses realize all their efforts are going to enrich a small group at the top, leaving them with very little. And this is also why AI, without the willing cooperation of humans, will also fail. When I read A Brief History of Intelligence by Max Bennett, I learned that one of the leaps in the evolution of intelligence was when hominids and other mammals started being able to look at a situation and imagine what would happen next.

1:37:06This is the difference between AI and a human scientist. A human scientist projects discoveries into their possible outcomes and possible developments. A scientist can extrapolate things that have not happened yet. AI simply chews up the mass of human discoveries and regurgitates the results. AI cannot dream. Humans can. This is why we educate ourselves, and this is why microbe TV and science education in general have a very important function in society. We learn how to learn. We learn how to imagine. We learn how to dream. That is the gift of science. Whoa, right on, Mike. Nicely done. AI cannot dream.

1:37:50Human skin. That's beautiful. Quotable quote. Well, I like that we're playing a role in this, Mike. Thank you very much for mentioning us. There are often times when I get insecure about what we're doing. I'm like, who cares about these begomoviruses? But that's not really the point. It's the way you get there. I now care about these begomoviruses. That's how you think and how you arrive at the solutions. It's not necessarily the solutions themselves, which are often elegant. That's great. That's how we get there and how we talk about it. Of course, I don't have the investment or responsibility in this that you do, Vincent.

1:38:35But I don't worry about that at all anymore. I just come here to yak with you guys and have a good time. And the papers, you know, I mean, this is my connection with science at this point. You send me papers and I read them. And that keeps me alive. It's just glorious. It's wonderful. All right, take the last one, Rich. It's pretty short. Lisa writes, I'm 62. My PCP denied me the HPV vaccine. I sent her a written argument trying to persuade her to prescribe the vaccine to me and included a select two academic references about the benefits in older populations. My history of HPV infection is documented in my chart, but she claims I've never had it.

1:39:22She literally lied to me and insists she is not allowed to prescribe this vaccine off-label. End of discussion. Then she blocked any further communication from me. Wow. Not a great way to cultivate trust. I will never go back now. I talked to my insurance company, have in writing the HPV vaccine is covered for me, no age restrictions, at 100%, it's$1 ,300. So it's not the insurance company. I finally had a light bulb, Planned Parenthood, talked with them last week. I can get this vaccine from them, no age limit, no descriptions, no restrictions, getting my vaccine in 48 hours and counting down.

1:40:08Happy my healthcare dollars are going to this organization too. Without you, I would never have known about the benefits of this vaccine for me. Thank you, Lisa. Thank you, Lisa. Yes. One of the things that this reinforces for me is that you have to be responsible for your own health care. Not all physicians are the same. They're not always right. And even the best ones are going to make mistakes. They're humans. So you have to take care of yourself. I'm very proud of this. Yeah, we don't give medical advice here on TWIV, but I will skirt that line by saying, Lisa, you need a new primary care provider.

1:41:00Oh, yeah. I think she knows that. Yeah. Yeah. That's totally unacceptable. Yeah. I'm very happy that we did this paper on TWIV about the meta-analysis. Yeah. So it makes me feel better. Today's science won't get anyone a vaccine, but does other things. Well, I don't know if you're a white fly listening. yeah let's do some pics of the week rich what do you have for us right new science fiction uh there is a new series underway uh by james s.a corey which is in fact the pen name for two authors a team daniel abraham and ty frank these are the dudes who created the expanse some years ago. A series of like nine novels and a number of novellas that was ultimately developed into a TV series as well was really excellent.

1:42:01They've come out with a new series. It's called the series is The Captive's War. And so far, there are two novels and one novella. and there is a third novel that is supposed to appear within a year or so. I have finished the first novel and the novella. The first novel is The Mercy of Gods and the novella is Live Suit. And I'm working on the second novel and they are every bit as good as The Expanse. If you liked The Expanse or if you like sci-fi in general, I would highly recommend this. This is, I mean, you're being abducted by aliens, dude. This is heavy stuff. It's great. Cool. Nice. Alan, what do you have?

1:43:00I have a website, climate.us. There used to be a good website called climate.gov where you could get all sorts of data about the climate. and of course that's been gutted and destroyed because that's what the current administration likes to do to things related to science. So a bunch of the former NOAA scientists who helped maintain that site salvaged the data and launched climate.us, which is an independent non-profit funded website that the administration can't touch and it is maintaining the same stuff that used to be on climate.gov. If you used to rely on that site, the new address to put in your bookmarks is climate.us.

1:43:50And I love that they did this, and I love what they've done. This thing is very well put together, and they've really – I mean, I didn't have a complete catalog of everything that was on climate.gov, but there's a lot here. Wow. This is great. I love these charts. Look at the dashboard at the bottom. The ice, the Arctic ice, the carbon dioxide, greenhouse gases, sea level. So cool. I've done this before. We've done this before. But I want to take this opportunity to restate the obvious. And that is the reason the government wants to suppress climate change research and anything about it is that the solution to the climate problem is to reduce or get rid of the reliance on fossil fuels.

1:44:42That means restricting, shutting down the petroleum industry. And they got a lot of money invested in that, so they don't want to touch it. So get rid of the whole idea of climate change. Say it's a hoax. Don't do anything about it so that you can preserve your interests in the petroleum industry. Let's be clear here. Short-term profits. And you're thrown away the long-term. Absolutely. This is truth, folks. Climate change is true. And the reasons that I just cited for the government's being against it are true, no matter what they say. Yep. My pick is a very interesting story. that broke this week in which I'm sure everyone has seen.

1:45:27This is a chemically defined synthetic cell capable of growth and replication. It's called Spud Cell. And I'm going to give you the website. It's biotic.org because the PI of this project, Kate Ademala, who's at the University of Minnesota, have made a nonprofit to spread this. She's decided not to profit by this discovery, but she established a nonprofit, which is what Biotic is, and it will get donations and they will help spread this technology. So what is it? So there's a preprint here on this website where there's a description. It is a cell-like system from completely defined components, 36 purified enzymes, a 90 ,000 base pair genome across nine plasmids, the lipid membrane.

1:46:19This thing, they put it together, they assemble it. It grows, it replicates, it divides, and you can do selection as well across multiple. You put some gene in that's better and it's selected for. It's amazing. That is amazing. It's very, very cool. I mean, eventually it peters out, right? But probably that'll get solved. They're working on that. So this is a completely defined system that you can now ask questions about and study as an organism. Right. So it grows by fusing with feeder liposomes that have lipids and ribosomes and enzymes and small molecules. And also, it doesn't have a cytoskeleton, yet it can still divide.

1:47:10It's very cool. I'm just waiting for the first virus of spud cell. But you can imagine this being used to make stuff. Maybe you would even make cells that you could give to people to treat diseases at some point. Who knows? This is very cool. This is just amazing. And as a lab tool, it's awesome. It's amazing. So you can check this. There are lots of articles about this all over the place. But this is their website, their words. Outstanding. Very cool. We have a listener pick from Lana to Vincent and the other esteemed Twivers. Greetings from Edmonton, Canada, Alberta, Canada, where June 2026 is likely going to be the rainiest June in over a century.

1:47:55Some sources state that we have had about 240 millimeters of rain so far compared to the average of around 70, and it continues to rain. we have experienced water restrictions due to the drainage system being at capacity, water pooling on roadways, flooded basements, walking path closures due to erosion. There is more rain in the forecast for the first part of July, but on the upside, there's not been a day with poor air quality due to smoke yet this year. I'm an analytical chemist by training and most recently a safeguarding research specialist at the University of Alberta, as well as an avid TWIV listener.

1:48:32Like so many others, I started listening to TWIV in early 2020 and haven't stopped. I think at least some TWIV listeners might enjoy poking around the periodic table through another podcast, the episodic table of elements. I don't know what else to say, except that it is like bedtime stories involving elements and the episodes are consistently fascinating and engaging. I cannot find any evidence that the person behind the podcast, T.R. Appleton trained as a scientist, but they may have missed their calling judging by the level of detail and rigor in each episode. A sincere thank you for all that you have done and continue to do for science education.

1:49:13Kind regards, Lana. The episodes are in order of increasing atomic number. Episode one is hydrogen. Episode two is helium and so on. It's great. It's a great idea it's going to be a self-limited podcast yeah yeah it is well they'll do something else maybe yeah all right now i feel good about twiv again vincent you can always feel good about you can always feel good it's good i need to actually i don't know if i've ever mentioned one of the gym classes i go to i'm going to shout out to john john you listening uh this guy uh takes up uh his station next to me in this class at one um one class i was plugging a singing event we were doing so i he had just recently joined the class so i introduced myself i said many of you know me rich condit i sing this is the event and a little later john who i had not met before comes up to me he says um uh rich condit twiv and i said yeah and it turned out i had actually his wife works at the buda library okay and i had done a thing for them uh during the pandemic uh she was apparently a twiv so he's a twiv listener so just this last monday i go in and recap he had questions about the last episode.

1:50:47So before class, I do a recap for him and we discuss it. It's great stuff. So, Quiv lives on. He's not a scientist, okay? Quiv does good things, Vincent. Hey, happy birthday, Rich. Oh, thank you. Oh yeah, happy birthday. It's Monday. How are you again? You're 78? 78. Cool. It's a little weird. You're healthy. You're going strong. You'll be good. Yeah, I guess. Go for it. I guess. It's TWIV 1337. You can find the show notes at microbe.tv slash TWIV. If you have any questions or comments or picks of the week, please send them. We'd love to hear from you very much. TWIV at microbe.tv. That's the email.

1:51:36And if you like these programs, we'd love your support. microbe.tv slash contribute. Ellen Dove is at ellendove.com and turbidplack.com. Thank you, Alan. Thank you. It's always a pleasure. Rich Condit is an emeritus professor, University of Florida, Gainesville. He is currently in Austin, Texas. Thank you, Rich. Sure enough. Always a good time. This is great fun. I'm Vincent Racaniello. You can find me at microbe.tv. I'd like to thank the American Society for Virology and the American Society for Microbiology for their support of TWIV, Ronald Jenkes for the music, and Jolene Ramsey for the timestamps.

1:52:16You've been listening to This Week in Virology. Thanks for joining us. We'll be back next week. Another TWIV is viral.