Bradley writes:

Dear Vincent and crew,

I was driving from Princeton to New Brunswick (New Jersey, of course) when I heard the short background to TWIV 541 and heard Kathy read: “The initial description of mitoviruses was accomplished through research on two related fungal pathosystems that are often confused by those with only passing familiarity in plant pathology”, I thought, geez, that sounds like something I would say. And sure enough, it was, from my AVR review on narnaviruses and mitoviruses a few years ago.

I am thrilled that you have taken a continued interest in mitoviruses. I was slightly disappointed that the paper you chose to highlight in TWIV 541 was Max Nibert’s largely bioinformatic 2018 paper. Slightly disappointed because Max is terrific and it’s a nice paper, but highlighted in the current issue of JVI was this paper from Massimo Turina’s lab in Turin that takes the plant mitovirus work a step further and describes experimental results with one of the viruses: The paper from Massimo’s group answers some of the questions you and the others posed in your discussion and would be worth visiting.

A quick elevator summary of mitovirus discovery: A group led by Ken Buck, a true pioneer in fungal virology at Imperial College, showed in the 1980’s that diseased strains of the Dutch elm disease fungus (Ophiostoma novo-ulmi) contained dsRNA that was consistent with mitochondrial inheritance (maternally inherited). Then in the early 1990’s, a postdoc in my lab and I showed that a similar element in the chestnut blight fungus, Cryphonectria parasitica, exhibited maternal inheritance, mitochondrial localization in fractionation experiments, and an RNA sequence that made sense only if you invoked fungal mitochondrial codon usage (UGA=Trp), among other properties: From there, the floodgates opened, and more than a hundred such elements have since been characterized in fungi, but relatively little real progress has been made. As you alluded to in your conversations – I think Alan made the point – mitochondria are hard to work with. We effectively demonstrated that through years of failed experiments, with some good successes. Regarding the name, I think I named both the new family Narnaviridae (naked RNA virus family,) and Mitovirus genus (self-explanatory) when we erected those taxa for ICTV for the 6th Report when Reed Wickner was Fungal Virus Subcommittee Chair immediately before I was. And yes, regarding Narnaviridae, I thought of the Chronicles of Narnia too, but it seemed to beat the competing suggestion Nudiviridae, which I thought sounded even sillier – and was nevertheless taken subsequently for a family of DNA viruses.

Fast forward to now, some progress on a couple of fronts: first, a bioinformatic study by Max that came out a bit earlier than the paper you discussed showed that “Mitovirus UGA(Trp) codon usage parallels that of host mitochondria” (it must show that – that’s the title of the paper): In other words, if you’re a fungus, the fewer Trp-encoding UGA codons your mitochondria have, the fewer your mitoviruses have. Makes sense, right? And second, in a recent JVI paper that you referred to, Vincent, Nobuhiro Suzuki and colleagues (I’m on the paper but they did the real work) showed that we could move mitoviruses among both closely related and more distantly related fungi by moving their mitochondria via protoplast fusion and repeated rounds of selection: Still difficult, but this should open a few doors.

Keep up the great work, I love the podcast, helps me keep my “no NPR 2016-2020” pledge, and I am constantly impressed by your collective scope and complementarity. And I especially enjoy it then you guys grope your way through a plant virus paper such as the eLIFE paper from Stéphane Blanc’s group in TWIV 539, with admirable enthusiasm but limited understanding of plant anatomy and biology – reminds me of the ancient Indian parable of the blind men and the elephant.

And I hope you keep your interest in mitoviruses and fungal viruses more broadly – there’s a lot going on in the field, though sadly limited funding.

Best regards,

Brad Hillman

Bradley I. Hillman, Ph.D.

Director of Research

New Jersey Agricultural Experiment Station;

Professor, Plant Biology and Pathology

Rutgers University

New Brunswick, NJ 08901

Edmund writes:

I think scala means staircase, maybe like a spiral staircase or from low tones to high tones.   And the weather in Pensacola is mild but overcast today. I love the weather on TWIV and of course the virology.

Les writes:

Re:Weekly Science Picks -> Alan Dove cherry blossoms

A biotech pioneer funded the Capitol’s Cherry Trees

Takamine Jōkichi funded a gift of 2000 cherry trees from the mayor of Tokyo to the city of Washington. I think it was his idea.

He was a pioneer of American biotechnology in the 19th century. He discovered adrenaline and a critical diastatic enzyme. Yeast can’t digest starch in grains. The enzyme converts starches to sugars

He had the first patent on a microbial enzyme in the United States.

Being Japanese, despite living in the United States for over 20 years and marrying a citizen, he could not become a citizen himself.…/mdd/v04/i12/html/12timeline.html

Rich writes:

Guys, once again many thanks for a very interesting show which was thought provoking. It got me thinking as to the difference between a virus and a plasmid. Apologies in advance if I have missed something obvious, but both replicate using the host cell’s machinery. Viruses are normally separately packaged in a capsid but this does not apply to the mitoviruses in TWIV 541 (and Hep D relies on Hep B capsid proteins). Also neither exit the cell so the host killing virus rule does not apply. Is the difference that Mitoviruses encode RNA polymerase so they are masters of their own destiny – or/and that plasmids do not exist in fungi (I have seen references to fungal plasmids)? So if a plasmid were to encode RNA Polymerase it would be classified as a virus?? Mitoviruses appear similar to viroids and some viroids replicate in plant chloroplasts (per Wikipedia – the Avsunviroidae), so are mitoviruses really a type of viroid? A possible talmudic question perhaps…



Angela writes:

Really cool TWiV! I’m a former Virologist who works in DNA Forensics. I always wondered if there were Mitoviruses. Or if mitochondria were evolutionarily related to viruses because mito replicate similar to some viruses (an example is parvovirus). Now I know there are mitoviruses and I have some catch up reading to do. Curious if the viruses integrate into the host mitochondrial genome and alter the sequence? If they do, a mother and child might not have the same Mito genome sequence and/or a single source profile may look like a mixture and this could wreak havoc on the work I do.

Thanks for these great shows! Helps keep me up on one of my favorite topics Viruses.

P.S. All the world’s a Phage!

Anthony writes:

Dr. Condit mentioned that — to be appreciated — rats need to grow fur on their tails.  It will take more than that. People view subterranean animals with disgust and arboreal animals with awe.  Nocturnal animals are feared while diurnal animals are accepted.

The biggest factor though are the proportions of the skull.  The elongated rat snout is a reductio ad absurdum of that of the adult human and so poses a threat.  The pushed in nose of the squirrel resembles a human infant’s skull shape and so elicits a response of attraction and caring.


Anonymous writes:

Dear TWiV, TWiM, and Immune,

The Measles issue ain’t going away because you have Chiropractors making rants.

Here is why: There is a convention called California Jam. It’s like an ASM Meet up but filled with Chiropractors and Anti-Vaxxers according to this post. One of the people in the video is named Heather Wolfson a Chiropractor she is one of the players who keep spreading the Anti-Vaxx rants in a constant Manner. The problem here is that she is Identified to the public as a health care provider who has a medical degree even though Chiropractors and MD’s are separate Entities.

This is when Measles is Affecting New York State though.

Shallee writes:

Hi. You mentioned archiving issues, well, the TWIV68 plaque assay movies are dead links for Science. And, I can’t find the fluorescently tagged late/early stage visualization of a plaque assay that you described in the episode. Can you help? Or are all three unavailable now? Thanks.

Angela writes:

Thanks for the great show!

Couldn’t stop laughing about your comments: It’s too GC rich!

In the lab I worked in as a graduate student, we used to say this all the time when our PCRs of HSV-1 genes failed. Those failures helped me learn how to troubleshoot PCR reactions. At my current job, when I mention GC rich sequences in primers used for sequencing mitochondrial genome regions, people look at me like I’m crazy.

Hearing that comment brought back some great memories.

PS I think the authors, when researching why the plaques were smaller forgot an area to look at: the packing of the viral genome into capsids. Perhaps capsids formation and/or packaging of the viral genome was not 100% efficient. Hence the smaller plaques.

Anthony writes:

(He wrote a letter to Dorit Reiss asking “why isn’t intentionally exposing a child to disease prosecuted as abuse?”)

If you’re asking whether there are laws that can be used, for example, against parents who take kids to measles or chicken pox parties, there are such laws. You would need political will to use them – there is prosecutorial discretion in the U.S. I suspect it would take serious harm to get them used against white, middle-class parents.

Unfortunately, our criminal justice system is not always even-handed.



Dorit Rubinstein Reiss

Professor of Law

UC Hastings College of the Law

Raphael writes:

Dear Alan, Dickson, Kathy and Vincent,

I was listening to your show on the science360 podcast.

You mentioned that both Europe and the US have reduced antibiotics use in livestock production, while the developing countries are (still?) using plenty.

While being true of course, it startled me a little as at least here in Europe there is a significant difference between the amount used per country. Of course there is also a difference in population of livestock or humans, but adjusted for that many of the larger countries still use far too much antibiotics. My point being, I found your comment to make it easy for us “developed citizens” to feel good about our livestock production, while we really should be more aware of what impacts our choices have.

Germany (being in the upper-middle segment of livestock antibiotics users and with a very strong conventional farmers union ) has a problem especially in the industrial pork production. It apparently is that bad, that pig farmers in some areas of the country going to the hospital for anything will be put into the infectious disease department of a hospital to protect the patients and staff from MRSA and similar.

So I believe we should be highly aware of how our food decisions impact this issue and that it is still highly relevant in the US and Europe as well as the developing countries.

The EU report source for the attached screenshot

Thank you for the interesting podcast.

Best regards,


Anonymous writes:

Dear, Twiv we have another case of a political activist going after a real virologist over vaccines. Dr. Peter Hotez from one of the TWiV Episodes has been targeted by Del Bigtree a Political activist in a rant.

Del Bigtree targets Dr. Peter Hotez in a rant while Bigtree gets called out for his rants

After Rockland County, New York, banned unvaccinated children from all public spaces last week as it battles a growing measles outbreak that originated in an Orthodox Jewish community, anti-vaccination activists likened the public health measures to the Nazi persecution of Jews that included forcing them to wear yellow stars.

In Austin, Del Bigtree, CEO of an anti-vax group called ICAN, wore a yellow star during a rally last Thursday to identify with parents who decline to vaccinate their children. A spokesman for Bigtree said he took the action “to let the Jewish community of Rockland County know he stands with them.”

After photos of Bigtree were posted on Twitter, the official account of the Auschwitz Memorial and Museum in Poland tweeted in response: “Instrumentalizing the fate of Jews who were persecuted by hateful anti-Semitic ideology and murdered in extermination camps like #Auschwitz with poisonous gas in order to argue against vaccination that saves human lives is a symptom of intellectual and moral degeneration.”

Jonathan Greenblatt, CEO of the Anti-Defamation League, said in a statement: “Groups advancing a political or social agenda should be able to assert their ideas without trivializing the memory of the six million Jews slaughtered in the Holocaust.”

Texas has one of the most organized and politically active anti-vaccine groups. Texans for Vaccine Choice, which organized the rally last week, receives support from tea party Republicans and some of the state’s most influential conservative organizations, state lawmakers have said.

Hotez, who has been an outspoken critic of the anti-vaccine lobby, called its latest actions “highly offensive” and asked the leadership of the state Republican Party to publicly denounce its actions. He added: “I don’t know what they think they gain by mocking the Holocaust.”

The rise in measles cases was both predicted and predictable, Hotez said. In a study last year, he and colleagues from several Texas academic centers identified pockets of vulnerability where the risk of measles and other vaccine-preventable childhood diseases is higher because parents hesitate or refuse to get their children immunized.

Ryan writes:

Dear TWiV,

We have a measles scare being reported in Sacramento.

This is the largest scare being reported in California so far though.

from the article

SACRAMENTO (CBS13) — UC Davis Medical Center confirmed Wednesday that 200 people may have been exposed to measles in the Emergency Department on March 17.

The hospital sent out letters on March 25 and 26 to those patients, alerting them of the possible exposure, according to public information officer Charles Casey.

Dean A. Blumberg, M.D., Chief of Pediatric Infectious Diseases, said a patient from Calaveras County came into the Emergency Department with a rash that turned out to be measles. According to Blumberg, another patient, 7-year-old Jackson, who suffers from a terminal illness, was evaluated in the same exam room as the patient with measles before doctors suspected measles and closed the room to be cleaned.

Doctors say Jackson did not have measles as of Tuesday, 16 days after he was exposed. Blumberg said it typically takes eight to 12 days from the time of infection to develop symptoms. The range can also be seven to 21 days.

No other cases of measles or symptomatic patients have been recorded at the medical center, Blumberg said.

This comes after three confirmed cases of measles in Placer County last month. The family was reportedly infected while visiting a relative in Butte County. Members of the Auburn Racquet and Fitness Club were possibly exposed to the virus on the night of March 18.