Posts Tagged ‘health’

Refutation of some rank nonsense

15 August, 2025

I had the misfortune today to follow a link to my page on History of Discovery of Viruses, which is included in Cann’s Principles of Molecular Virology that I revised in 2023 for a 7th Edition. This landed me here, which I thought was a serious page on the history of Virology – but I was very wrong.

Very, very wrong.

Instead, it is a densely-written, pseudoscientific collection of incorrect assumptions, applications of hopelessly dated definitions, and bold statements of “fact” that are entirely horseshit. I have commented there, but I doubt my comment will survive. Instead, I reproduce it here for your delectation. Or amusement. Don’t bother to be outraged and accuse me of anything that proves to me that you are a virus denialist, because I shall simply delete it.

“Given that you refer to me, I feel at liberty to comment on your entire piece of “work” that you have laid out here.

That is, that it is a complete and unmitigated crock of shit. The seemingly blind insistence that early workers with viruses did not isolate an “organism” or satisfy Koch’s Postulates – which were, by the way, just that and not rules – presumes that their observations were invalid and that, by extension, all modern virology is based on falsehoods.

Which, as a virologist of nearly fifty years standing, I can categorically state is a complete and utter crock of shit, as I stated previously.

Don’t you think science has advanced since Beijerinck, Mayer and Ivanovsky? Don’t you think that the invention of the electron microscope and discovery of both DNA AND RNA as genetic materials (the latter only for viruses and viroids) has shown us that, yes indeed, there ARE “sub-microscopic” pathogens that are acellular and which have to use cellular ribosomes to complete their life cycles – unlike any other form of life.

I have used the discovery of TMV – which text you apparently refer to (https://rybicki.blog/2012/02/07/a-short-history-of-the-discovery-of-viruses-part-2/) – and various other discoveries about TMV to tie together the scientific discoveries about viruses, over an 80+ year period. That is, the demonstration that an “acellular” fluid could cause plant disease, through to the precise localisation of every atom in the structure of TMV virions by X-ray crystallography. I have included this in a textbook that you should obviously read (https://www.sciencedirect.com/book/9780128227848/canns-principles-of-molecular-virology), in that it would illuminate some gaping voids in your knowledge and in your understanding.

Moreover, people working in my lab have, as others have done elsewhere, recreated infectious virus genomes by synthesis of DNA oligonucleotides and subsequent use of them to infect plants – and mammalian cells. Viruses are real, therefore, and any amount of hand-waving on your behalf will not alter that fact.”

Plasticity of viral genomes and new receptors

15 July, 2024

I was prompted to go on a bit of a rave – pardon, to expand on some long-held opinions – on Bluesky the other day (@edrybicki.bsky.social) after reading this post from Daniel Goldhill (@influenzal.bsky.social):

“I wrote a short piece about a new flu subtype (H19) which uses a surprising receptor. We’ve known about glycans terminating in sialic acid as a receptor for flu for 70 years but the virus still surprises us! Great work by Karakus et al.

I quoted his comment – “Perhaps, the ancestors of all extant viruses had to be flexible in their ability to switch to new receptors.” by saying:

“And perhaps quite a few still are??”

So let me expand a bit on that: it’s a bit dismaying how many people are still wedded to the “one enzyme/protein, one function” paradigm – which was never true, and which basically was a convenient fiction to make biochemists happy. The fact is that proteins are happy to bind to ANYTHING you can think of, and probably quite a few that you can’t, by simple virtue of accidental molecular complementarity, somewhere in their structure – and given that classic virus envelope glycoproteins are pretty big AND multimerised, that’s a lot of structure. Meaning that, like any good scientist, envelope proteins can hold more than one receptor in mind, and some of their binding may be completely adventitious AT FIRST – however, if it is selected for (more virions enter cells, or do it faster), then suddenly it becomes a virtue, and – new tissue tropisms / higher infectivity result(s). I am spurred on here by the example of SARS-CoV-2 S protein, which has mutated in front of our morbidly fascinated eyes since early 2020 to increase its binding affinity to human ACE2 by orders of magnitude, which has resulted in greatly increased infectivity and a significant increase in R0 for virions.

Thus, expecting that any given given viral membrane glycoprotein will only bind ONE receptor is naive: it will bind one (or more) WELL, and others badly – until selection occurs, because the new property is a survival mechanism when faced with neutralising Abs, for example. Viruse genomes are plastic: they change quickly to adapt to adverse environments, and even small changes that confer only slight advantages, will be selected for, and then reselected and improved over time. That this could result in the HA of an influenzavirus being first, able to bind another molecule than the sialic acid-bearing glycoproteins that are the canonical receptors; second, improving that binding by selection of mutations that improve binding affinity; third, losing the ability to bind the original receptor while preserving the new interaction, should not come as a surprise to any serious virologist. Moreover, these sorts of receptor changes / additions are almost certainly still going on, rather than being an ancestral condition.

And yes, this is going into the new edition of Cann’s Principles of Molecular Virology, whenever that comes out 😁