Worms at Chernobyl resistant to mutation.

[Write4U]

Hoping this is not viewed as a sidetrack, but as another piece of the puzzle. I see a possible connection between microtubules and "insulation"(?) from radiation? This is outside my scope of knowledge, so if anyone can offer a comment or link to a pertinent paper,
I think it might be interesting in context of radiation resistance during mitosis

Are microtubules electron-based topological insulators?
Varsha Subramanyan1, Kay L. Kirkpatrick2,1, Saraswathi Vishveshwara3 and Smitha Vishveshwara1
Published 15 August 2023 • Copyright © 2023 The author(s)

Abstract
A microtubule is a cylindrical biological polymer that plays key roles in cellular structure, transport, and signalling. In this work, based on studies of electronic properties of polyacetelene and mechanical properties of microtubules themselves (Spakowitz A. J., Phys. Rev. Lett., 103 (2009) 248101), we explore the possibility that microtubules could act as topological insulators that are gapped to electronic excitations in the bulk but possess robust electronic bounds states at the tube ends.

Through analyses of structural and electronic properties, we model the microtubule as a cylindrical stack of Su-Schrieffer-Heeger chains (originally proposed in the context of polyacetylene) describing electron hopping between the underlying dimerized tubulin lattice sites.

We postulate that the microtubule is mostly uniform, dominated purely by GDP-bound dimers, and is capped by a disordered regime due to the presence of GTP-bound dimers as well. In the uniform region, we identify the electron hopping parameter regime in which the microtubule is a topological insulator. We then show the manner in which these topological features remain robust when the hopping parameters are disordered.

We briefly mention possible biological implications for these microtubules to possess topologically robust electronic bound states.

Introduction
Organic polymers and biomolecules have served as inspiration for discovering new condensed matter phenomena, with path-breaking insights developed for both biological systems and physical models [1,2]. The Su-Schrieffer-Heeger (SSH) model proposed in the 1980s for polyacetylene serves even today as a simple paradigm for topological phases of matter and charge fractionalization [3].

Such models have led to opening entire fields of study, bringing theoretical and experimental advances in our understanding of materials [4]. On the biological side, the fundamental units of the model, involving dimerization and sublattice symmetry, are building blocks for a range of complex macromolecules. Here, we investigate microtubules as a highly promising instance for extending such topological behavior in rich and diverse ways.

more..... https://iopscience.iop.org/article/10.1209/0295-5075/acec94

 

[exchemist]

Hoping this is not viewed as a sidetrack, but as another piece of the puzzle. I see a possible connection between microtubules and "insulation"(?) from radiation? This is outside my scope of knowledge, so if anyone can offer a comment or link to a pertinent paper,
I think it might be interesting in context of radiation resistance during mitosis

Are microtubules electron-based topological insulators?
Varsha Subramanyan1, Kay L. Kirkpatrick2,1, Saraswathi Vishveshwara3 and Smitha Vishveshwara1
Published 15 August 2023 • Copyright © 2023 The author(s)

more..... https://iopscience.iop.org/article/10.1209/0295-5075/acec94

Reported for thread hijacking.

 

[James R]

Moderator note: Write4U has been warned for off-topic posting.

Due to accumulated warning points, Write4U will be taking another break from sciforums.

 

[Pinball1970]

Hoping this is not viewed as a sidetrack, but as another piece of the puzzle.

One step forward which I acknowledged, then MT and a ban.

I am hoping you take what you need to from this.

 

[Pinball1970]

But did you ever get anywhere with the enquiries you were going to make about the inconsistencies in that article?

I had trouble posting to the article so I have contacted the site. I have an account there now so should be no issue as far as I am concerned.

Thanks for reporting the side track. I was actually engaging in what I thought was the first proper interaction with him then the next post was MT. I was actually disappointed, thought I had got somewhere.

 

[exchemist]

I had trouble posting to the article so I have contacted the site. I have an account there now so should be no issue as far as I am concerned.

Thanks for reporting the side track. I was actually engaging in what I thought was the first proper interaction with him then the next post was MT. I was actually disappointed, thought I had got somewhere.

I really do think we have to stop Write4U corrupting otherwise intelligent and informative threads with his obsessions. He has wrecked countless discussions in the past by introducing red herrings and I for one have really had enough of it. Ideally I would have preferred it if his post had been excised from the thread and dumped, but I'm not a mod.

Back to the topic, here's an absorption spectrum I found for melanin:

The visible spectrum extends to the right from about 380nm, so everything to the left is UV absorption.


Melanin seems to comprise a wide range of poorly characterised polymers of 5,6-dihydroxyindole and related species:

I gather melanin precursors are formed from tyrosine:

The red squiggly lines indicate linkages to form polymer chains. One can see that these heterocyclic aromatic units, with or without further conjugation via polymer chains, are likely to have π* orbitals that can be populated by UV absorption.

As for a role as radical scavengers, I think I recall phenolic and quinone type molecules are good at stabilising free radicals, as they can give up H• from the hydroxyl group to react with a radical and then delocalise the remaining odd electron round the aromatic rings, i.e. in a π* orbital. What I don't believe is that molecules of this type can have any special role in absorbing nuclear (α, β or γ) radiation directly, since that will be a function of the atomic nuclei present, which are just C, N, O, H as found in all other organic molecules.

 

[Pinball1970]

Ideally I would have preferred it if his post had been excised from the thread and dumped, but I'm not a mod.

Yes please. Not just because it is my thread and something I am interested in, but because this is an interesting subject that can teach us a lot about, mutation, genetics, and evolution.

 

[Pinball1970]

As for a role as radical scavengers, I think I recall phenolic and quinone type molecules are good at stabilising free radicals, as they can give up H• from the hydroxyl group to react with a radical and then delocalise the remaining odd electron round the aromatic rings, i.e. in a π* orbital. What I don't believe is that molecules of this type can have any special role in absorbing nuclear (α, β or γ) radiation directly, since that will be a function of the atomic nuclei present, which are just C, N, O, H as found in all other organic molecules.

Ok, a little bit of reading/catch up is required from my side.

Thanks for contributing. I will feedback if the org gets back.