Steen writes:

Thanks again for the recent focus on plant viruses, including our paper on TWiV 343. I think you all did an admirable job summarizing our results. Thanks especially to Kathy for feedback on the writing. (Note: my adviser wrote the paragraph you didn’t like.) I also enjoyed the recent florendovirus episode and Katie’s follow-up on multipartite genomes of seed-transmitted nepoviruses.

Informative hosts: Regarding the question of using a natural host (“why not try turnips?”) it is worth noting that TuMV can be detected in wild A. thaliana populations in Spain. Many plant viruses have a broad host range, and their names reflect the agricultural context in which they were discovered.

I agree with the broader point that comparative genetic analysis of host-virus specificity can be interesting and informative. Hopefully CRISPR technology will expedite genetic analysis in turnips, yams, or whatever species the funding agencies prefer. As Dickson mentioned, flowering plants appeared only about 130 million years ago, so we think many of the insights from A. thaliana will translate. Hopefully mouse-eared cress does not lie about the important things.

Rub inoculation:Regarding Rich’s question about cross-contamination: I do not think that we have ever detected virus coat protein in the mock-inoculated plants. We are more tender than the guy is the wheat video—you have gently caress the A. thaliana leaves to avoid causing too much mechanical damage. Also we do not really rinse off the plants afterward, especially not with a hose! TuMV is nice—the virions are not so stable on surfaces. Turnip crinkle virus (also used with A. thaliana) reportedly requires much more care in avoiding cross-contamination, and the historically important Tobacco mosaic virus is highly infectious on a large number of species—it’s a pain!

Suppressor transgenes:Dickson asked whether transgenic expression of HC-Pro in plants is possible. Indeed it is, but this makes A. thaliana sterile. Transient or inducible expression can be used to get around this problem.

Yeast RNAi/AGO conservation:You briefly mentioned that Schizosaccharomyces pombe (fission yeast) has an Argonaute gene. S. pombe has been a great model for studying RNA-directed DNA methylation through RNAi pathways. Interestingly, the frequently used budding yeast Saccharomyces cerevisiae has lost RNAi, perhaps to better accommodate a helpful virus that kills off competitors. RNAi may have been discovered earlier if it were present in S. cerevisiae.

A review I linked to in my message noted that Argonaute genes “have been linked to disorders such as fragile X syndrome and some forms of autoimmune disease.”

Finally, petunias came up, so I wanted to mention that flower color in transgenic petunias has also been important for understanding RNAi, and that petunias are highly susceptible to several viruses—they are used as “sentinel”/”canary in the coal mine” plants for that reason.

81 ºF (27 ºC) in St. Louis. Dark ominous clouds outside my window. It has been a rainy summer—my colleagues’ drought experiments in the field have turned into submergence tolerance experiments.

Andy writes:

Hi Twivonauts!

I was disheartened after hearing about the recent deluge of potentially fraudulent data surrounding publications by Olivier Voinnet. I’m a graduate student working in plant virology/biotechnology, and found Voinnet’s name on a paper I was currently referencing for a presentation. This was troubling to me because I was literally basing one of my upcoming experiments on the conclusions of the paper.

In my opinion, this kind of thing is bespecially harmful, because now I don’t know if I can trust the conclusions of the paper, or if I should continue with the experiment. It seems one of the unfortunate drawbacks of the digital age is the temptation to use photoshop as an alternative to rigorous science. Looking at some of the images in question, these are not even good fakes: the gel lanes were blatantly copied and pasted, or simply flipped upside down in hopes no one would notice! I can’t help but wonder if Voinnet was only caught because of how blatant the fabrication was. This raises the disconcerting question of how many better fakes have gone undetected.

On a humorous note, I ended up searching for other papers with Olivier Voinnet’s name that I may have read previously. In the utmost irony, I came across the following paper, with Olivier Voinnet as the sole author:

How to become your own worst enemy

Olivier Voinnet

Nature Immunology 14,315–317(2013

Published online 19 March 2013

It’s up to 110 Fahrenheit here in Arizona and while we don’t ever get any snow, we just got the first dust storm of the summer this past week. Every time you guys complain about the rain or clouds, I think, “Come take some of our sun! I’ll take the rain!” I guess it’s all relative.

Thank you all so much for the insightful and amusing podcast! I’ve been listening since my virology professor (Brenda Hogue) told our class about the podcast a few years ago. Now my girlfriend and I wait eagerly each Sunday for the new episode to be posted!



Gabriel Victora writes:

Maybe you saw this- not exactly virology but probably argues that the cause is not viral


Tate writes:

Hi Prof. Racaniello, here’s a new paper on Rituximab in ME/CFS. It was open label with the placebo group from the first study but I think they gave maintenance doses vs the single dose that was given in the first study.




Hello Vincent and TWIV friends. Here is something about CFS.

Alice writes:

I want to share the source of “mice lie and monkeys exaggerate” with you.

I was catching up with my thesis advisor, Dave Weiner at U. Penn*, and asked him if he knew the origin of the phrase:

“Mice lie and monkeys exaggerate is a quote from myself. I gave a talk in South Africa, in Cape Town on the use of NHP in HIV vaccines studies and I went through animal models and that was one of my conclusions. I don’t believe it was the first time I used it but it caught on there. I have used it for quite some time and it’s been quoted in Science. Paul Offit uses it in talks and has credited me with it.”

So for what it’s worth that’s where it comes from.”


*David B. Weiner, Ph.D.

Professor, Department of Pathology and Laboratory Medicine

Chair, Gene Therapy and Vaccine Program, CAMB

Co-Leader Tumor Virology Program, Abramson Cancer Program

University of Pennsylvania, Perelman School of Medicine

Wink writes:

“MERS-CoV, like other coronaviruses, is thought to spread from an infected person’s respiratory secretions, such as through coughing.”

Edward writes:

Hello there,

Edward from Alberta Canada here. Just want to say I’ve recently started listening to your podcast and am hooked. I’m just a simpleton but am finding the show intriguing and educational. I’m finding myself listening to several episodes a day trying to catch up. Keep up the great work!

Sincerely Edward

Stefan writes:

Hello everyone at TWIV!

I’m an ambitious, and subsequently naive,  eighteen year old who is looking to get into the field of cellular biomechanics and microchemistry. I love your podcasts and it’s killer education and it is amazing! The segment in 342 regarding aDNA and the acido/thermophilic virus mentioned. Hydration was brought up as a primary cause of the formation of A-DNA, as well as the sporillic qualities that may have caused both those virus and the gram-positive sporilli (?) To evolve the ultra-durable nature of the organism. My extrapolation would be to ask if there is any way for typical B-DNA, say that of an antibody, to be forced into an A-DNA structure and have those undefined proteins that were mentioned, bound to the DNA. An application to an antibody would be far fetched, most likely,  but implications, such as a cancer cell developing those qualities would be terrifying. It may not be plausible for human tissue, but it could possibly used as a time release mechanism. HIV and other immune-related disorders.

Thanks so much for looking at this and sorry if it is nonsensical for the most part. I greatly look forward to continuing to listen your show and learn in  the field!



Guenter writes:

TWiV is like a book without summary and without table of contents or index or like a paper without abstract. You can read through it sequentially, but it’s hard to look things up, include links, switch forward and back or skip chapters. By using .mp3 you want to force us to listen to the whole thing (or avoid it altogether) ?!

I think TWiV is too good to be lost in the mp3 archives without being able to google for keywords later. Or to quote from it and discuss in other forums or blogs.


Eric writes:

Dear TWIVers:

In TWIV 339, after the discussion on population growth, Vincent (possibly jokingly) commented that the problem will be no jobs.

As a listener pick, I would recommend “Economics in one lesson” by Henry Hazzilit. The lesson is given in the introduction:  In economic policy (i.e. government rules etc.) one must examine ALL the effects, not just the ones that can be seen to benefit some (usually the politicians benefit the most anyway).

As an example, the push for a $15 minimum wage (MW) should rather be called the “robot subsidy act”, since the effect of such a law will likely replace all jobs lower than $15 in productivity with machines.

The MW also could be called a minimum skills law, because its effect is to cut off all workers who have lower skills from getting to the lowest rungs of the employment ladder. After all, the MW law does not require that anyone be hired, only that it is forbidden to hire at a lower rate. You can tell this is true by looking at who is pushing the MW act the most (higher priced union workers for one). As is often the case, the reason that some push for some government act is to put a clamp on competition.

A MW law of course hurts the youngest the most, and because they become unemployable (by government decree), they will need to find work in the black markets, most likely in drugs, prostitution, etc.

So, before you think that there would be no jobs in the future, remember that it’s laws that restrict jobs (MW, license, etc.). And if you think that working for $5 an hour is bad, how about $0 an hour with no job at all. And that $5 would very likely go much further if the government would get out of the way.

To plagiarize from another great show:  Another TWI-Gov is parasitic.



Anthony writes:

Christina writes:

Hi Dr. Racaniello,

I’m Christina, a Filipino PhD student at the University of Georgia. We met when you visited UGA last Spring :). I wanted to follow up on a letter that Giann wrote on TWIV 342 and ask for her (his?) email. Maybe I could give her some tips and as well as some contacts. I totally understand Giann’s frustrations because I was in the same position as she was a few years ago. Luckily, I have a supportive mentor, faculty, family, and friends that made it possible for me to pursue my dream of becoming a virologist 🙂

Thank you so much for TWIV! Not only for making virology accessible to a wide audience but you’ve made possible for people to connect. More power to you and the TWIX team (^.^)

Yours truly,


It is 31 degrees C and 35% humidity here in Athens, GA. The weather here feels so much like home!

Suzanne writes:

I was just catching up on last week’s podcast after realizing I’d missed some of it. Podcast listening time goes out the window when both of my kids are home all day in the summer. And even when I get time I’m often distracted. This time around I heard you reading Giann’s letter and I had the thought that if money for application fees and travel turn out to be the main hurdle for him to get a shot at a good virology program, maybe he could crowdfund it. I bet there are listeners who’d be willing chip in. I would!
Thanks again for your podcasts. And as well as all the fascinating info and discussion, thanks for introducing us to the music of Ronald Jenkees. I’ve since bought all his albums! They’re great!

Stephen writes:

Last week the Martian trailer was picked, and it was mentioned that the Martian could get a record breaking 3 picks of the week (the book, the trailer, and the movie). Let’s push that up to a potential 4. I’d like to pick the audiobook version of the Martian, with excellent narration by RC Bray, has won an audie award in its own right. Highly recommended.

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