Neva writes:

Howdy Super Professors,

I was late listening to ‘The Cat in the HAART’ (I have been living in interesting times here lately) and was very warmed and delighted by the kind words of Rich about our lunch meeting. We had a wonderful time and great conversation about a variety of subjects with a good amount of laughter. Certainly a testament to Rich and Ibby’s generous friendliness. It was much fun and I certainly hope we can all meet again, Rich, when you return to Austin. And, Kathy, it was delightful of you to remember Buda and share the Buda Generator you found in the wilds of Alaska, Thanks.

The TWIX-casts are so fascinating. I have always been interested and amazed by biological sciences. It’s true what Dr. Racaniello says “You just couldn’t make this stuff up!'”

It was fun to be reminded of the ‘From Buda to stump grinding” episode which I thought was hilarious. Your collegial travels down rabbit holes are quite fun. I really appreciate, too, when you each take time to broaden discussions for us non-scientists.

You all are doing great work! Science education in general seems to be especially needed in these interesting times. I am puzzled and saddened by the various forms of science denial in our society, especially the anti-vaccine proponents who can cause actual damage to children and populations. The logistics of vaccine programs are challenging enough without people freaking out and rowing backwards.

In my opinion, the current crop of presidential debaters display a surpassing willful ignorance and dismissal of facts and history…but that’s politics. I focus on listening to and reading about science and technology as a positive respite from “da News”.

Keep up the wonderful podcasts super-profs. You are very much appreciated.


from Buda TX

Eric Delwart writes:

Dear Twivomics

Did you catch that kerfuffle at the republican debate about vaccination? Do these candidate expect parents will bring their kids in every few weeks to “space out” their vaccines shots? Some vaccines are more essential than others? That was probably a reference to the highly effective papillomavirus vaccines driving young kids crazy with lust. So sad seeing the most efficacious and cost-effective medical advances of last hundred years being constantly dissed. Do they really believe that there is a conspiracy driven by the entire medical profession? Not a peep from the other candidates.

Bill writes:

Vincent, Dickson, et al:-

Here I am in sunny Toronto at 18C/65F,

Listening to the description of the proliferation of bacterial colonies and the associated bacteriophages in the baby’s gut and how the composition matured and developed to decrease the bacteriophage population to a lower steady state at 2 years, even as the bacterial mass grew.

This seems to me to be the manifestation of the CRISPR immune process in the bacteria, who eventually increase their internal stored phage destroying patterns to that steady state.

As to why this does not progress to extinction of the phages, one must assume the phages  also do their own pattern fiddling to grab more food, and we might also import new phages who kick ass for a while.

Then I think about diseases such as cholera. Are the cholera bacteria carrying with them phages of their own that clear the decks of other bacteria by as camp follower phages – as it were, to allow the cholera bacteria unlimited lebensraum? Do cholera bacteria carry phages as intracellular warriors that are shed as intercellular shock troops?

Does cholera have another cellular immune system, analogous to CRISPR that blocks the phages in our gut from killing the cholera? Or does Cholera just have it’s own CRISPR – how much variation occurs in assorted CRISPRS?  Why is cholera immune to our phages if it is?

As to links, did you know Edgar Allen Poe had a cat?

I dare you to read it with a straight face…

Dennis writes:

Docs, just a quick follow up on the UVc robot for helping to clean contaminated rooms.  I’d wondered whether UVc could kill viral particles.  According to this googled answer below, yes.  Just a note:  it will not be long before that UVc cart will become an increasingly capable robot.  Elon Musk asserts that Teslas will fully self drive from 2018.  Daimler-owned Freightliner trucks are now legally self driving across Nevada.  Have you seen the Japanese robot prototype that can care for invalids?  It can pick up a patient and gently move him or her around.  In the not distant future this capability plus UVc could become a cost effective method of partial disinfection.

Google answer:  Yes – germicidal UVC lamps kill up to 99.9% of most viruses, airborne bacteria and mold spores. Yes. Germicidal UVC lamps will kill up to 99.9% of mold and help prevent future mold growth.

Answer Source:  Frequently Asked Questions | American Ultraviolet



Greg writes:

Dear TWIV Illuminati,

I am writing with regard to the discussion that you had on two recent TWIV episodes (353 & 354) concerning viruses bringing cellular molecules along for a ride. This began as a more specific discussion of the incorporation of cGAMP into virus particles, where Vincent raised the interesting question: will anything that is over-expressed in a cell end up in virus particles? On the following episode Rich Condit mentioned a paper published in 1987 that looked at incorporation of a foreign protein into pox, which in that case could be detected by virtue of the protein’s enzymatic activity. Ultimately, you came to the follow up idea of expressing GFP during infection to see if fluorescence could be detected in virus particles. Well, the answer is assuredly yes… at least for a herpesvirus.

Two years ago I had a talented student in the lab, Kevin Bohannon, use GFP/RFP dual-tagged pseudorabies viruses to look at viral particle architecture. One of the many controls in this study was a virus that expressed GFP that was not fused to a virus protein. That is, upon infection of a cell, GFP was produced but not targeted to enter newly-assembling virus particles. GFP was packaged into virus particles nevertheless. Although the level of GFP incorporation was variable from particle to particle, it could reach levels that were comparable to a lower-abundance viral structural protein.

Because GFP can non-specifically package into this enveloped virus, I would suspect something as small as cGAMP would as well without the need of a directed mechanism. A danger of being enveloped, perhaps.

Keep up the great work & best to you and your co-stars,

Greg Smith

(A beautiful sunny 70F/21.1C day in downtown Chicago)

Bohannon, K.P., et al., Differential protein partitioning within the herpesvirus tegument and envelope underlies a complex and variable virion architecture. Proc Natl Acad Sci U S A, 2013. 110(17): p. E1613-20.

Steph writes:
By the way, loved this past TWiV #355! Naturally, I really enjoyed the discussions about the milk virome and how it contributes to the infant gut virome (keeping this in my ‘Ideas for Future Research’ folder). There have been many papers published on the milk microbiome but there is currently a dearth of work on the milk virome. We know that viruses like HIV do get into milk via replicating in immune cells that have trafficked to the mammary gland. In addition, replication by mammary epithelial cells themselves can also contribute to milk transmission of HIV. However, there is a paucity of information for non-HIV eukaryotic viruses and phages and their contribution to the milk virome.

Reed writes:

Dear TWiV Team,

I’d like to suggest a new podcast called the Bench Warmers ( as a listener pick. The podcast is hosted by graduate students and centers around life in the sciences from the perspective of graduate students.

The second episode “Oh Sh*t” features interviews asking current and former students about the most expensive thing they’ve broken in the lab and features some excellent stories. Does anyone on the TWiV team have a good story along the same vein?

Thanks for the company while I’m plating cells in the hood.


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