Jess writes:

Hello TWiV Team,

As always, appreciate the show. Especially ep. 461 since so much of my time involves reviews of similar experiments! Thank you for acknowledging the papers are not easy to decipher! When reviewing for safety:  safety of the vectors, safety of the transgenes, safety of the procedures there can be a lot of cross-checking to learn about every single piece of the experimental setup (particularly the molecular biology)!  

During episode 461 a couple things came to mind:

-Apologies if this is a naïve question but maybe other listeners were also curious about this–why does doxycycline delay the degradation of a virus? I don’t know that you said why and I just missed it, but the mechanism was lost on me but piqued my interest. Is it related to ubiquitin?

-Also, do you know much about studies regarding interaction or synergy between these viral vectors?  I just wonder as we wade further into viral vector research if anyone has seen anything of interest when using more than one modified vector in sequence like in the experiment mentioned in 461?   

-Lastly, would it be possible in the future to pull out a list of books that you’ve recommended either in picks or in conversation during the episodes? I often listen while I drive and if you don’t call out a book as a pick, I’ve had trouble finding the books you mention in passing as being good reads once I get to my destination  🙂


Unrelated to scientific papers (no need to cover on the show):

-Regarding gender of letter writers/authors, just wanted to raise the issue that although the comments and banter about this on the show is based in an effort to respect the letter writers/authors, it is often discussed in the context of a gender binary. A benefit to having several pockets of progressive communities in this current divided political/cultural climate is that more people are openly identifying as not belonging to the traditional cultural gender constructs. Many people don’t want to identify on one side or the other of the gender binary and reject the notion of gender altogether. Granted it is common to speak about individuals based on the culturally accepted norms, I just wanted to raise the issue that maybe the conversation in the future can include the possibility that the person in question doesn’t subscribe, so as not to exclude someone in that category?

Thank you!


Jay writes:

Does it really matter what a writer’s gender is? If in doubt, use their name to refer to them, or use “they/their/them”. Simple, uniform, generic, no chance of offending anyone’s sensibilities and emphasises that it really isn’t important in the given context. If it makes someone uncomfortable due to grammatical pedantism, well then, welcome into the future. 😉


P.S. Long-time listener, first time writer. Newly-transitioned HIV behavioral research data manager (@ISMMS). Thank you all for the incredible program (as well as the other TWiX podcasts).

listener pick:

Omega Tau science and engineering podcast (some episodes in German, some in English)

Neeraj writes:

Hi Twivvers,

  This is Neeraj from Sutrovax, Inc. (I have been meaning to write in for a while but it hasn’t happened of late so here it is). I hope all of you are doing great and hopefully it’s been yet another year of memorable scientific experiences. First and foremost, many heartfelt congratulations for completing 9 years engaging in this incredibly generous undertaking. I am personally most thankful to Prof. Racaniello and Despommier for having done both TwiV and TwiP series. These have just been incredibly information dense and fact rich podcasts for me, which I can listen to over and over again, not to say the least how much I have enjoyed the amazing chemistry you both share. A major investment like these can’t only be a product of curiosity and incentive, but of personal admiration too.

Today is even more special for another reason. My alma mater, Rockefeller University, posted another major achievement to their crown jewel. Prof. Young was awarded the Nobel prize for the discovery of circadian rhythms, which is something I have always been interested and fascinated by (I was lucky enough to have attended a few of his seminars during my grad school days). This is one of the primary examples where there is a much direct and clean correspondence between protein and physiology. And not to say that this field also has some of the most appropriate and fun names for the proteins involved namely Timeless, doubletime and period (hence the reference in the title). In relation to this, I was also happy when you recently brought in Jonathan Weiner, who is the amazing writer of time, love, memory (one of my all-time favorite scientific reads). Having spent an amazing 5 years as a graduate student at RU, I am never surprised by the heights that its faculty scales. With such rich history (from generation of the yellow fever vaccine that was discussed a few twivs ago to circadian rhythms to discovery of dendritic cells), it’s a phenomenal melting pot of ground breaking scientific discovery. My class of 22 graduates had 17 nationalities within it, which bolstered a rich sense of cultural exchange in me and something I have enjoyed ever since. There is so much to learn from each other at the scientific and human level and RU facilitates that in every possible way. The richness of scientific expertise in the entire neighborhood encompassing Weill cornell and Sloan kettering research institutes is just remarkably unique. I personally feel that science alone without able mentorship at times can leave you disgruntled and frustrated and for this particular reason, I would personally like to commend and thank the entire TWiV crew. Each one of you in engaging in an act of selflessness which you didn’t have to, but I am glad that you did. I am absolutely certain that millions like me have greatly benefited from your incessant desire to learn and explore. Thus kindly keep up the great shows and here’s to many many many^n years’ worth of TwiVVing, TwiPPing and TwiMMing ahead, since there’s an ocean of information out there and without a good teacher, students would feel inundated, lost and overburdened.

And like we used to sing during RU’s grad student outings,

We are, we are Rock U (you guys are the true rockstars),



Pete writes:

This excerpt from NPR News caught my eye:

With the award, seven Americans have now been honored among the nine researchers who have been recognized so far in the 2017 Nobel season. Toward the end of Wednesday’s event, a journalist asked Royal Swedish Academy of Sciences Secretary General Göran K. Hansson about the prevalence of Americans.

In his reply, Hansson noted that since World War II, the U.S. has “allowed scientists to perform fundamental research” and focus on large-scale projects that might not have immediate impact or applications. He added that they have also been able to do so largely without political pressure.



Erwin Duizer writes:

Dear Twivers,

I listened to your podcast twiv 459 and want to thank you for the extra attention you paid to our paper on the WPV2 incident.

In discussing you raised some points I can provide a bit more info on, not too much since we are preparing a paper on all the lab results including quantification, and some of the production facility related information is not for me to share. I am glad you noticed we did put in quite some effort to obscure the identity of the operator.

Production facility

The aerosols were formed when a leak occurred in the tubing connected to a virus cultivation unit.

Production facility is gapIII compliant, including obligatory showering out, but no respiratory masks were worn since the production process is overall a completely closed process.


Please realize that also with Sabin vaccine you can get infected and shed PV, sure, the probability of infection after exposure is a bit lower and shedding is definitely shorter and of lower titer, but there really is no guarantee to not become infected after Sabin vaccination. In the Netherlands we stopped providing OPV to polio vaccine production facility employees about 3 years ago.


We realized from the start that shedding in the sewage was not okay with respect to GAPIII, but we did not have anything else up and running to contain stools at that moment that would improve the situation for both, GAPIII and public health. Realize that the removal of PV2 from the OPV had no effect at all in the Netherlands since we have never used OPV, so we have no decline in protection against PV2.

On the long term detection in the sewage system: we sample really small populations in the sewage, a couple of hundred households. With the detection limits as in our paper on environmental surveillance (Polio and Measles Down the Drain: Environmental Enterovirus Surveillance in the Netherlands, 2005 to 2015. Benschop KSM, van der Avoort HG, Jusic E, Vennema H, van Binnendijk R, Duizer E. Appl Environ Microbiol. 2017 Jun 16;83(13).)  and some modeling as in “Risk assessment, risk management and risk-based monitoring following a reported accidental release of poliovirus in Belgium, September to November 2014. Duizer E, Rutjes S, de Roda Husman AM, Schijven J. Euro Surveill. 2016;21(11):30169.” we estimated that 3-6 weeks detectability was likely.

We briefly considered PV excretion in urine, but since we did not find any hint pointing at this being relevant we dropped it from our “to do list”. I am very interested if you have info that this might occur.

I send you this email from a partly foggy Bilthoven, but forecast promises temperatures of 20 C, slightly above normal and with almost no wind it is quite pleasant to go ride my rowingbike (check

With kind regards


Erwin Duizer, PhD

Head of section Enteric Viruses

Centre for Infectious Diseases Control

National Institute for Public Health and the Environment


The Netherlands

Chicken Gunia

Johnye writes:

From last year. Great special in Delhi.

John writes:

Dear Twiviridae,

I hope all is well in the Twivth Dimension.

Why is it that particle-to-PFU ratio is in common usage and not Efficiency of Plating?

Personally I find it easier to think of efficiency of viral infectivity as 1 PFU in x number of particles. Given particle-to-PFU is in common usage I think I might be missing something.

It’s 14 degrees C and raining in Melbourne Australia.

Thank you for all you do. May the infectivity of your podcasts be ever as efficient as Semliki Forest Virus! (PFU = Constitutive Listeners).

Best Regards,

John B

Samer writes:


Thanks for doing these podcasts. I’ve enjoyed them quite a bit. I have two points about animal-related comments made during TWiV 458.

First, regarding the exudate from the cut surface of the growths in rabbits infected with the myxomatosis leporipox virus: This is not pus (purulent/suppurative exudate), but in fact a proteoglycan matrix produced by the “myxoma” cells (undifferentiated mesenchymal cells) and does very much resemble mucus, and is often referred to as “mucinous” in pathological descriptions:

Second,  Dickson said that leopards do not have molars. Felids do, in fact have small molars, but usually only one and they are not used for chewing in the same was as herbivores and omnivores:


Samer Jaber, DVM


Trudy writes:

Dear TWiVers,

Upon Vincent’s recommendation, I read The Beak of the Finch and Time, Love, Memory by Jonathan Weiner. What I love about reading good books is that they often lead to other good books. Time, Love, Memory repeatedly mentions Arrowsmith, a 1925 novel by Sinclair Lewis about the culture of science. I’m only about 1/3 way through but I’m really enjoying it so far, so I would like to suggest it as a pick of the week!


Mark writes:

Hello to the TWiV Quadrangle,

Generic FU – you’re all doing a great job. Keep up the good work.

I have two listener picks that your audience may enjoy:

  1. iOS App – Human Anatomy Atlas – URL:

This app runs on either iPhone or iPad. The app provides a 3D model of the human body. Users can explore specific systems like skeleton, lymphatic, digestive, nervous, etc. The app allows a virtual dissection to explore tissue and visualize spatial relationships. Its possible to display detailed notes of the organ or part being viewed. You can take notes and sync with other devices using iCloud. Some will be shocked at the price for this app — a mere $0.99, less than a buck. Note there are in-app purchases for instructional videos that supplement the app.

  1. podcast “Master in Business” – URL:

This podcast is produced by Bloomberg by its host Barry Ritholtz on your island in Midtown Manhattan. Each episode is an interview with someone having a distinguished career in finance. Guests range from Nobel Laureates like William Sharpe, Robert Schiller, Daniel Kahneman; investment innovators like Ed Thorp, Bill Miller, Cliff Asness, Jack Bogle, and others involved in the many subfields of finance. In a style analogous to TWiV, the host asks the guests about their backgrounds, how their career started, and the work they do in finance. He has a few stock questions that get lots of insight: “What do you know today that you wish you knew when you were starting your career?” and “What would you tell a millennial or new graduate wanting to enter your field?”

All the best.


PS – The weather this week in the Bay Area has been glorious. Temps in the mid-seventies (F), clear skies and warm sun.

PPS – Continue being nice to Dickson.

PPPS – Let me be mean to Dickson by asking if Urban Agriculture will ever have a new show?