Hi Dr Racaniello,
I am a long time listener of TWIV and really enjoy the informal scientific discussions. I listen to TWIV while working in the lab and am trying to catch up on TWIM and TWIP episodes too.
I have been dilly-dallying on the idea of writing to you for a while now as the paper that I am suggesting is in a way self-promotion. However, I thought that you may find this study interesting as it presents a very interesting example of a virus (HCV) using a liver-specific miRNA (miR-122) to protect its genome from 5'-exonuclease-mediated degradation (attached paper). This paper not only describes a novel way used by an important human virus to slow down the rate of viral RNA decay but also adds a novel mechanism of action to the repertoire of mechanism of action of cellular miRNAs. Usually miRNAs down-regulate expression of target genes by decreasing translation and/or enhancing the rate of degradation. However, HCV has devised ways to use miR-122 to both increase its translation, protect its genome from 5'-exonuclease-mediated degradation and potentially prevent detection of 5'-triphosphate containing viral genome by the cellular immune response.
I enjoy all three podcasts and look forward to many more episodes of them. Thanks for keeping me up to the speed on some of the interesting developments in virology and microbiology as well as fascinating discussions on parasites.
Department of Microbiology
Mount Sinai School of Medicine
New York NY
Dear twiv team,
Very nice of you to have read my letter. Boston marathon is history for this year. Despite of the crazy heat, I made it to the finish. Took me much more than I expected (final time 3:26:39) but still, it's done. Was great! Ahead is a new running season with new goals in my mind and new twiv episodes to spice up the time in running shoes.
Thank you again for your time and effort!
(a typical name for boys born around 1985 in Estonia :) )
Department of Virology
University of Freiburg
Dear TWiV Doctors,
I stumbled upon your webcast this morning, and as an aspiring virologist I am looking forward to going through the archives. I particularly enjoyed this episode because I work for Dr. Kathy Hanley at NMSU doing research into dengue virus-mosquito interactions, and my eventual career goal after I get my PhD is with the PHS. An interesting thing about dengue that was outside the scope of the interview is that dengue also has an extant sylvatic cycle in both Southeast Asia and Africa. This is important because it could serve as a model system for other as yet un-emerged zoonotic viruses, as well as currently emerging viruses (chickungunya being an excellent example). Furthermore it is a potential complication should an effective tetravalent vaccine be approved for use, as these sylvatic viruses are entirely capable of spilling over into humans, and have the same epidemic potential.
It will be an interesting year for arboviruses with the early onset of the mosquito season across much of the country, along with the presence of dengue in the Keys, as well as West Nile.
Keep up the good work
P.S. I am not ashamed to admit that I carry Principles of Virology around with me on a daily basis.
I don't know if you remember, but we met briefly when I was at Columbia visiting Ian Lipkin's lab two summers ago. At the time I was a postdoc with David Baltimore. I really enjoy your Virology Podcast, and listen to it whenever I get a chance.
I have to say however, that as an influenza virologist I've been a bit disappointed in how you and your co-hosts have treated the H5N1 research debate. I think this issue is more complex and deserves more balanced consideration than almost all commentary, including your own, has given it. I thought of this today when I read an essay by Peter Sandman (which I have forwarded below) on the topic. The essay is the most intelligent thing I have read about the debate, and I think it has some good suggestions. I know you and your podcast represent one of the most respected voices in virology (certainly I respect it a lot!), so I thought I would forward along the essay.
Assistant Member, Basic Sciences Division
Fred Hutchinson Cancer Research Center
Hello future, Vincent, Allan, Rich, Dickson, and all other present contributors. I started listening to TWiV in November 2011 and am up to episode #95, so hello from 2010! I would like to express my deepest gratitude for the work that you do and the education you provide to the listener. I can say that this show has singlehandedly assuaged my fear of vaccination, which was built on hearsay and fear mongering. I would like to ask a few questions and share a video I’m hoping at least Vincent will like.
TWIV #92 discussed plant viruses making plants resistant to drought and other adverse conditions. Is it possible that there are similar viruses conferring resistance to people living in extreme climates, such as Saharan Africa, or the Arctic Circle? Or for that matter could there be microbes, or parasites that help people in these extreme climates manage to live there? For example Dickson has mentioned that the Inuit and Yupik peoples are nearly 100% infected with toxoplasmosis and perhaps other meat borne parasites. Is it possible that these people have given an advantage in dealing with the extreme conditions present in the Arctic Circle by the viruses, microbes, and parasites present there?
On a different note rabies seems to have been around humanity and with humanity for a long time. I realize that the natural host for rabies is bats, however my question is more homo-sapiens-centric. Does its current disease cycle in humans maximize transmissibility? If it does how do hydrophobia, manic mood swings, and whatever other signs and symptoms exist aide in transmission? If not, why hasn’t the virus mutated to a form that can better transmit in humans? If it doesn’t transmit well from humans, could the lack of mutation be because of the limited amount of human borne infections comparative to viruses that mutate much more quickly to maximize transmission?
My third question is related to viruses used to construct things. I think you guys mentioned that viruses can be used to construct batteries. Could a virus be used to construct the most basic structures inside a cell. As an experiment would it be possible to create any, if even the simplest, structures that make up a cell using viruses as the building agent? I realize this idea leads to a “were viruses the root of the tree” type of argument, but frankly I’m not as interested in that question.
As for the video, Vincent mentioned that he liked the Abbot & Costello skit “Who’s on first?”. This is a modern rendition of that skit that I think uses a really clever twist. I should point out that I do not watch sports so I have no idea how current or valid the content is.
Thank you all for your excellent work, and ditto to Rich on what to tell everyone if you had 5 minutes to talk to them. I apologize for the length of this email. I generally save up questions until I am overwhelmed and need to write. Please feel free to read or omit whatever you feel like.