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About viruses and viral disease

TWiV 879: Indolent, resistant, and losing our TMPRSS

24 March 2022

TWiV reviews the emergence of remdesivir-resistant SARS-CoV-2 during treatment of a persistently infected immunocompromised patient, and how altered TMPRSS2 utilization by the Omicron variant influences infectivity and fusion.

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Show notes at microbe.tv/twiv

Q&A with A&V Livestream 3/23/22

23 March 2022

Virologists Amy Rosenfeld and Vincent Racaniello answer your COVID-19 questions (or any virus questions) on this livestream of 3/23/22 at 8:30 PM eastern US.

TWiV 878: Shape matters sometimes

20 March 2022

TWiV revisits chronic wasting disease of cervids and the ability of the prions to infect meadow voles and raccoons, and the suggestion that stochastic assembly of influenza virus particles may play a role in phenotypic diversity.

Hosts: Vincent Racaniello, Dickson Despommier, Rich Condit, and Amy Rosenfeld

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TWiV 877: COVID-19 clinical update #106 with Dr. Daniel Griffin

19 March 2022

In COVID-19 clinical update #106, Daniel Griffin covers failure of ivermectin to improve hospitalization, increased hospitalization of children with Omicron, seroconversion of children versus adults, effectiveness of Pfizer mRNA vaccine in children, high vaccine effectiveness in Finland against Omicron, distinct long COVID clinical phenotypes, and estimating worldwide excess mortality.

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Show notes at microbe.tv/twiv

Capsids and nucleocapsids

17 March 2022

One aspect of virology that is confusing to students is the concepts of capsids and nucleocapsids. These two terms describe two different ways that viral nucleic acids and proteins are arranged in virus particles.

The capsid (from the Latin capsa for box) is the protein shell surrounding the nucleic acid genome. Below are two different types of capsid, constructed with helical (left) and icosahedral symmetry. In both cases the nucleic acid is covered with a protein shell:

A nucleocapsid is defined as the nucleic acid-protein assembly within the virus particle. This term is used when the assembly is a discrete substructure in the particle. The term ‘substructure’ seems to confuse students. What exactly constitutes a substructure?

Let’s define substructure with examples. If we take the two capsids shown above, and add a membrane, then the nucleic acid-protein assembly (formerly a capsid) becomes a nucleocapsid:

The nucleic acid-protein assembly within the particle is a nucleocapsid because it is a substructure.

If we remove the protein capsids from both viruses, we no longer have a substructure and there is no longer a nucleocapsid.

The SARS-CoV-2 virus particle has a nucleocapsid, as illustrated below. The RNA genome is present in the enveloped particle as an RNA-protein complex (the proteins are shown as green circles):

Adding a membrane is not the only way to make a nucleocapsid. If we add protein to a genome within a naked icosahedral capsid, we have a nucleocapsid:

Recently it was found that the DNA genome of icosahedrally ordered Mimivirus is elegantly wrapped in a 30 nanometer protein shield. This arrangement gives this non-enveloped virus a nucleocapsid.

The concept of a nucleocapsid substructure is not difficult to grasp in the context of multiple examples. And to make things even easier, the word nucleocapsid should remind you of the nucleus, which is a substructure in the cell.

Images created with BioRender

TWiV 876: Spillover market with Michael Worobey

17 March 2022

Michael Worobey joins TWiV to explain evidence that SARS-CoV-2 emerged via the wildlife trade and that the Huanan market was the unambiguous epicenter of the COVID-19 pandemic.

Hosts: Vincent Racaniello, Rich Condit, Kathy Spindler, and Brianne Barker

Guest: Michael Worobey

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Show notes at microbe.tv/twiv

TWiV 875: Animal house

13 March 2022

TWiV discusses the virome of game animals in China, and the finding that binding of sarbecoviruses to ACE2 is an ancestral and evolvable trait.

Hosts: Vincent Racaniello, Dickson Despommier, and Amy Rosenfeld

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Show notes at microbe.tv/twiv

TWiV 874: COVID-19 clinical update #105 with Dr. Daniel Griffin

12 March 2022

In COVID-19 clinical update #105, Daniel Griffin discusses changes in brain structure after infection, dementia in patients with pneumonia, Paxlovid in children, mask effectiveness in schools, host factors and severe disease, post-acute symptoms, and the mission of CEPI.

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Show notes at microbe.tv/twiv

TWiV 873: Pig viruses and big viruses

6 March 2022

TWiV reviews the six known coronaviruses that infect pigs and what can be learned about human infections, and how the giant Mimivirus DNA genome is organized into a nucleocapsid.

Hosts: Vincent Racaniello, Alan Dove, Rich Condit, and Brianne Barker

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Download TWiV 873 (128 MB .mp3, 107 min)
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Show notes at microbe.tv/twiv

Trial By Error: British GP Journal Retracts “Opinion” About Lightning Process Written By LP Practitioner

5 March 2022

By David Tuller, DrPH

This week, a journal under the umbrella of the British Journal of General Practice published–and a day later unpublished–a laudatory piece about the Lightning Process from a Lightning Process practitioner. The author, Anna Chellamuthu, is also a GP at Royal Cornwall Hospital. She wrote that the controversial program combining neurolinguistic program, osteopathy and life-coaching cured her daughter of ME/CFS and inspired her to train in the technique herself.

The article in BJGP Life was called “Reflections on NICE, CFS/ME, and the Lightning Process.” It functioned as both a tirade against the new ME/CFS guidelines from Britain’s National Institute for Health and Care Excellence and an advertisement for an unproven commercial intervention. The new NICE guidelines, issued last October, explicitly advise against offering ME/CFS patients the Lightning Process.

[Read more…] about Trial By Error: British GP Journal Retracts “Opinion” About Lightning Process Written By LP Practitioner

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by Vincent Racaniello

Earth’s virology Professor
Questions? virology@virology.ws

With David Tuller and
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Contents

Table of Contents
ME/CFS
Inside a BSL-4
The Wall of Polio
Microbe Art
Interviews With Virologists

Earth’s Virology Course

Virology Live
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Virologia en Español
Virology 101
Influenza 101

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