Is consciousness to be found in quantum processes in microtubules?

Write4U · Apr 13, 2021

billvon said: ↑

I figured. You're pretty blind to that sort of thing.
Click to expand...

And that is to my discredit?

Well, to your credit, you are not trying to bilk anyone out of anything, as those two were trying to do. You just use the same tactics they do.
Click to expand...

What an odd observation. And what are those tactics. Persuasive arguments?

Instead of muckraking and trying make me out as a bad guy, why don't you give some of my links a try and see if am trying to con people into false and deceptive ideas or if I am trying to inform people of new and exciting developments in the nano sciences.

Log in or Sign up to hide all adverts.

Write4U · Apr 13, 2021

Can this count as one proof of microtubules contributing to emergent consciousness?

Witness the slime mold, a brainless but smart multi-nucleic single celled organism that can solve mazes, design railway networks, has a learning circadian rhythm, and can walk as a pseudopod. The last especially important for motility and extending the hunting range of the slime mold.

A pseudopod or pseudopodium (plural: pseudopods or pseudopodia) is a temporary arm-like projection of a eukaryotic cell membrane that are developed in the direction of movement. Filled with cytoplasm, pseudopodia primarily consist of actin filaments and may also contain microtubules and intermediate filaments.[1][2] Pseudopods are used for motility and ingestion. They are often found in amoebas.
Click to expand...

https://en.wikipedia.org/wiki/Pseudopodia

On the role of the plasmodial cytoskeleton in facilitating intelligent behavior in slime mold Physarum polycephalum
Abstract

The plasmodium of slime mold Physarum polycephalum behaves as an amorphous reaction-diffusion computing substrate and is capable of apparently ‘intelligent’ behavior. But how does intelligence emerge in an acellular organism?
Click to expand...

Through a range of laboratory experiments, we visualize the plasmodial cytoskeleton—a ubiquitous cellular protein scaffold whose functions are manifold and essential to life—and discuss its putative role as a network for transducing, transmitting and structuring data streams within the plasmodium.
Click to expand...

Through a range of computer modeling techniques, we demonstrate how emergent behavior, and hence computational intelligence, may occur in cytoskeletal communications networks. Specifically, we model the topology of both the actin and tubulin cytoskeletal networks and discuss how computation may occur therein.
Click to expand...

Furthermore, we present bespoke cellular automata and particle swarm models for the computational process within the cytoskeleton and observe the incidence of emergent patterns in both. Our work grants unique insight into the origins of natural intelligence; the results presented here are therefore readily transferable to the fields of natural computation, cell biology and biomedical science. We conclude by discussing how our results may alter our biological, computational and philosophical understanding of intelligence and consciousness.
Click to expand...

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4594612/

and

Note that the only significant number of organelles are the microtubules in the cytoplasm of the slime mold. All data processing in slime molds is via microtubules and seems to be causal in acquiring emergent semi-intelligent abilities.

Log in or Sign up to hide all adverts.

Write4U · Apr 13, 2021

Just for quick reference to microtubule videos;

https://www.google.com/search?q=amazing microtubules

Log in or Sign up to hide all adverts.

Write4U · Apr 14, 2021

Role of microtubules in processing "colors"

Visualization and Analysis of Microtubule Dynamics Using Dual Color-Coded Display of Plus-End Labels

Abstract

Investigating spatial and temporal control of microtubule dynamics in live cells is critical to understanding cell morphogenesis in development and disease. Tracking fluorescently labeled plus-end-tracking proteins over time has become a widely used method to study microtubule assembly.
Click to expand...

Here, we report a complementary approach that uses only two images of these labels to visualize and analyze microtubule dynamics at any given time. Using a simple color-coding scheme, labeled plus-ends from two sequential images are pseudocolored with different colors and then merged to display color-coded ends. Based on object recognition algorithms, these colored ends can be identified and segregated into dynamic groups corresponding to four events, including growth, rescue, catastrophe, and pause.
Click to expand...

Further analysis yields not only their spatial distribution throughout the cell but also provides measurements such as growth rate and direction for each labeled end. We have validated the method by comparing our results with ground-truth data derived from manual analysis as well as with data obtained using the tracking method. In addition, we have confirmed color-coded representation of different dynamic events by analyzing their history and fate.
Click to expand...

Finally, we have demonstrated the use of the method to investigate microtubule assembly in cells and provided guidance in selecting optimal image acquisition conditions. Thus, this simple computer vision method offers a unique and quantitative approach to study spatial regulation of microtubule dynamics in cells.
Click to expand...

Please Register or Log in to view the hidden image!

Figure 1. General strategy of the dCCD method. A.

Illustrations of microtubule behaviors underlying the rational of the dCCD method. Growing microtubules (labeled by EB3-GFP at plus ends) can grow, pause, or undergo catastrophe, while shrinking microtubules (lacking EB3-GFP) can be rescued, pause, or continue to shrink. When EB3-GFP labels from two sequential images are pseudocolored (green in the nth frame and red in the n+1th frame), their relative position in the merged dCCD images generates different color combinations or codes representing four of these dynamic events.
Click to expand...

Green-reds represent growing ends, as EB3-GFP labels advance along newly-added tubulin at the tip of polymerizing microtubules. Red marks ends which regain EB3-GFP labels in the n+1th frame, and indicates rescue from shrinkage to growth. Green reveals ends undergoing catastrophe and losing EB3-GFP labels in the n+1th frame, while yellow labels pausing ends with EB3-GFP present in the same location of both frames. B. Construction of a dCCD image.
Click to expand...

Two raw fluorescent images acquired at 5 sec intervals from a COS cell expressing EB3-GFP were processed to remove background and then pseudocolored, with the first image (nth) in green and the following image (n+1th) in red. They were merged to generate a dCCD image. Four types of color-coded ends can be readily seen (green-red: solid rectangle, red: solid circle, green: dashed circle, and yellow: dashed rectangle). Scale bars: 5 µm.
Click to expand...

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0050421

exchemist · Apr 14, 2021

Write4U said: ↑

Role of microtubules in processing "colors"

Visualization and Analysis of Microtubule Dynamics Using Dual Color-Coded Display of Plus-End Labels

Abstract

Please Register or Log in to view the hidden image!

Figure 1. General strategy of the dCCD method. A.

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0050421
Click to expand...

This is colour labelling introduced by the experimenters, in order to investigate the behaviour of microtubules, you fool. The microtubules are not processing anything.

You are just quoting random stuff about microtubules you have found on the internet, without any idea what it is about.

billvon · Apr 14, 2021

exchemist said: ↑

This is colour labelling introduced by the experimenters, in order to investigate the behaviour of microtubules, you fool. The microtubules are not processing anything.

You are just quoting random stuff about microtubules you have found on the internet, without any idea what it is about.
Click to expand...

But it's MICROTUBULES!

Write4U · Apr 14, 2021

billvon said: ↑

But it's MICROTUBULES!
Click to expand...

That's what this thread is about. Are you complaining that I am staying on topic?

billvon · Apr 14, 2021

Write4U said: ↑

That's what this thread is about. Are you complaining that I am staying on topic?
Click to expand...

Nope, not at all!

Write4U · Apr 17, 2021

Proteomic approaches to understanding the role of the cytoskeleton in host-defense mechanisms
Marko Radulovic†,1 and Jasminka Godovac-Zimmermann1
The publisher's final edited version of this article is available at Expert Rev Proteomics
See other articles in PMC that cite the published article.

Abstract

The cytoskeleton is a cellular scaffolding system whose functions include maintenance of cellular shape, enabling cellular migration, division, intracellular transport, signaling and membrane organization.
Click to expand...

In addition, in immune cells, the cytoskeleton is essential for phagocytosis. Following the advances in proteomics technology over the past two decades, cytoskeleton proteome analysis in resting and activated immune cells has emerged as a possible powerful approach to expand our understanding of cytoskeletal composition and function. However, so far there have only been a handful of studies of the cytoskeleton proteome in immune cells. This article considers promising proteomics strategies that could augment our understanding of the role of the cytoskeleton in host-defense mechanisms.
Click to expand...

Unlike the skeleton in higher organisms, the cellular skeleton is an adaptive and dynamic cellular network of protein polymers involved in cellular function in terms of movement, transport, secretion and shape. It also provides a platform for regional activities such as signaling, bio synthesis and energy production. In immune cells, it regulates a number of cellular functions that are related to the immune response, including migration, extravasation, antigen recognition, phagocytosis and cellular signaling/activation
Click to expand...

Keywords: actin, cytoskeleton, host defense, immune cell, immune response, mass spectrometry, microtubule, protein, proteomics, purification strategies

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4261605/

Write4U · Apr 17, 2021

From a highly recommended site of real science. Thank you exchemist.

Microtubule Organization in Neurons

The neuron is a highly specialized cell whose morphology is thoroughly linked to its function. Microtubules are prominent components of the neuronal cytoskeleton that provide architectural support for axons and dendrites and provide railways to transport cargoes across potentially long distances. Understanding the organization of microtubules in neurons can provide insights into how neuronal structure influences function. Important questions include how microtubules are organized in neurons, how microtubule stability and dynamics are regulated in different specialized neuronal sub-compartments, and how microtubule defects are implicated in nervous system disease.
Click to expand...

https://www.researchgate.net/public...ule_Organization_in_Neurons/citation/download

Write4U · Apr 17, 2021

And more from ResearchGate as recommended by exchemist.

Low and behold, there is an entire section devoted to microtubules.... paradise....
Please Register or Log in to view the hidden image!

(continued from "computers are incapable....... in the Alternate Science subforum)

Mathematically Modeling (artificial) Sentient Consciousness

Abstract

We explain how memories are created, stored, and retrieved by individual neurons, how objects are recognized, and how neuro-brain-plasticity works with regards to new experiences and learning.
Click to expand...

Microtubules (MTs) in 'our' neurons act as bio-induction coils that guide nearly everything that goes on in the neuron. The action potential moving up or down a neural axon changes the electric field inside the axon via a magnetic field around the axon and neuron.
Click to expand...

As the electric field variation advances in the axon-in time with the action potential-the tubulin proteins in the MTs are forced to fire in a sequence of orchestrated action in a spiral around the MTs in a manner similar to a current in the wire of an induction coil. This induces a relatively strong momentary magnetic field B within the MTs.
Click to expand...

As the MT cylinders are long and narrow the field B goes to zero outside (around) the MTs. When this occurs, the induced bio-inductors fire an EM pulse (soliton) resulting in the MT emitting a soliton that resonates with the same length MTs, as well as nearby axons, causing interference patterns between neighboring MTs in the same axon. These interference patterns quantize the nuclear magnetic spins of water molecules for neighboring MTs in a specific pattern that matches the sensation(s) of the external world. That pattern (of magnetic vector potentials is stored in spacetime point-by-point) as a memory. A reverse process recalls these memories.
Click to expand...

Self-referential action, evolving into self-awareness

Einstein recognized that the laws of physics had to appear the same for all observers, stating that observation (itself) is independent of absolute spacetime. As such, when a new incoming pattern is created, it is compared to already existing patterns, initiating recognition.
Click to expand...

Here, complexity theory can be modeled as an expanding number of quantum mechanical observational measuring systems that are only relatively autonomous as they are all connected by a common observer. Everything in our model of reality is resolved by adopting the 0-D point as the original Riemannian point-element from which our more advanced Riemannian space-time structure of physical reality evolves.
Click to expand...

This may also be the basis for Srchoedinger's equation, including how fields of probability arise and collapse. In Bernhard Riemann's original conception of curved spatial surfaces, an n-dimensional space is embedded in an n+1 dimensional manifold wherein all three-dimensional coordinate locations are united. Whenever n = 0, a non-dimensional (0D) point functions as an invariant absence, wherein each 0D point is kept from collapsing back into the Void via a twist.
Click to expand...

https://www.researchgate.net/public...ly_Modeling_Artificial_Sentient_Consciousness

I'll be mining this site as a recommended authoritative science library.
Again, thank you exchemist, for this excellent recommendation.

Write4U · Apr 18, 2021

exchemist said: ↑

This is colour labelling introduced by the experimenters, in order to investigate the behaviour of microtubules, you fool. The microtubules are not processing anything.
Click to expand...

No, just a matter of poor editing on my part.
Originally I was going to post from another link, but when I ran across this I felt it demonstrated how microtubules behave and quoted from that site, without editing the opening sentence. I believe the quoted portions as well as the illustration itself make it abundantly clear that the colors shown were pseudo-colored images to visually demonstrate the self-referential reversals.

You are just quoting random stuff about microtubules you have found on the internet, without any idea what it is about.
Click to expand...

I read every narrative before I copy and paste it in my post. Proof lies in the fact that I parse the quoted paragraphs for ease of reading. The original articles are presented as one large block. I separate the large block into smaller blocks, for easier reading and selection for comment.

It is kinda sad that you are still not convinced of my sincerity and every little flaw in any of my post is a fatal blow to the entire content of the post, according to your prejudicial view of my mental capacity and ability for understanding narratives of complex science. Your obsessive criticisms and ad hominems are so unproductive and bordering on being obsessive. I am positively contributing to interesting topics.
Your crusade against my participation is really only contributing negatively to the science I quote from usually very reliable sources.

For the volume of posts, I believe my work shows remarkably few errors. And most of them are in the semantics, not my interpretation of the science. For the sparsity that you post, I often see small errors in your posts. I ignore those because I am interested in the content of what you post, not how well you present it.

Lighten up, I am not your enemy!

Write4U · Apr 28, 2021

Re: Nano-pore processors.

Study suggests how to build a better 'nanopore' biosensor
by Ben P. Stein, National Institute of Standards and Technology [/quote]

Please Register or Log in to view the hidden image!

Credit: CC0 Public Domain

Researchers have spent more than three decades developing and studying miniature biosensors that can identify single molecules. In 5 to 10 years, when such devices may become a staple in doctors' offices, they could detect molecular markers for cancer and other diseases and assess the effectiveness of drug treatment to fight those illnesses.
Click to expand...

To help make that happen and to boost the accuracy and speed of these measurements, scientists must find ways to better understand how molecules interact with these sensors. Researchers from the National Institute of Standards and Technology (NIST) and Virginia Commonwealth University (VCU) have now developed a new approach. They reported their findings in the current issue of Science Advances.
Click to expand...

The team built its biosensor by making an artificial version of the biological material that forms a cell membrane. Known as a lipid bilayer, it contains a tiny pore, about 2 nanometers (billionths of a meter) wide in diameter, surrounded by fluid. Ions that are dissolved in the fluid pass through the nanopore, generating a small electric current. However, when a molecule of interest is driven into the membrane, it partially blocks the flow of current. The duration and magnitude of this blockade serve as a fingerprint, identifying the size and properties of a specific molecule.
Click to expand...

https://phys.org/news/2021-04-nanopore-biosensor.html

And what, is that biosensor?

Model of ionic currents through microtubule nanopores and the lumen. Holly Freedman, Vahid Rezania, Avner Priel, Eric Carpenter, Sergei Y. Noskovd, Jack A. Tuszynski

It has been suggested that microtubules and other cytoskeletal filaments may act as electrical transmission lines. An electrical circuit model of the microtubule is constructed incorporating features of its cylindrical structure with nanopores in its walls.
Click to expand...

This model is used to study how ionic conductance along the lumen is affected by flux through the nanopores when an external potential is applied across its two ends. Based on the results of Brownian dynamics simulations, the nanopores were found to have asymmetric inner and outer conductances, manifested as nonlinear IV curves.
Click to expand...

Our simulations indicate that a combination of this asymmetry and an internal voltage source arising from the motion of the C-terminal tails causes a net current to be pumped across the microtubule wall and propagate down the microtubule through the lumen.
Click to expand...

This effect is demonstrated to enhance and add directly to the longitudinal current through the lumen resulting from an external voltage source, and could be significant in amplifying low-intensity endogenous currents within the cellular environment or as a nano-bioelectronic device.
Click to expand...

https://arxiv.org/abs/0908.1209

river · Apr 28, 2021

Write4U said: ↑

Re: Nano-pore processors.

Study suggests how to build a better 'nanopore' biosensor
by Ben P. Stein, National Institute of Standards and Technology
Click to expand...

Please Register or Log in to view the hidden image!

Credit: CC0 Public Domain
https://phys.org/news/2021-04-nanopore-biosensor.html

And what, is that biosensor?

Model of ionic currents through microtubule nanopores and the lumen. Holly Freedman, Vahid Rezania, Avner Priel, Eric Carpenter, Sergei Y. Noskovd, Jack A. Tuszynski
https://arxiv.org/abs/0908.1209[/QUOTE]

Biology manipulating the periodic table .

Write4U · Apr 28, 2021

river said: ↑

Biology manipulating the periodic table
Click to expand...

Well, you tell me .

All I am trying to suggest in this thread, is that MT may be of primary importance in the emergence of consciousness, by whatever means Electro-Magnetic, Electro-Chemical, Quantum processes.....?

Bundles of Brain Microtubules Generate Electrical Oscillations

Abstract

Here we show that bundles of brain MTs spontaneously generate electrical oscillations and bursts of electrical activity similar to action potentials. Under intracellular-like conditions, voltage-clamped MT bundles displayed electrical oscillations with a prominent fundamental frequency at 39 Hz that progressed through various periodic regimes. The electrical oscillations represented, in average, a 258% change in the ionic conductance of the MT structures.
Click to expand...

Interestingly, voltage-clamped membrane-permeabilized neurites of cultured mouse hippocampal neurons were also capable of both, generating electrical oscillations, and conducting the electrical signals along the length of the structure. Our findings indicate that electrical oscillations are an intrinsic property of brain MT bundles, which may have important implications in the control of various neuronal functions, including the gating and regulation of cytoskeleton-regulated excitable ion channels and electrical activity that may aid and extend to higher brain functions such as memory and consciousness.
Click to expand...

Introduction

The above arguments support a potentially relevant role of electrical oscillations on brain MT bundles, which should be critical to neural function. We recently reported that MT sheets sustain electrical oscillations 19, which are driven by a permanent electrical polarization from local asymmetries in the ionic distributions between the intra- and extra-MT environments.
Click to expand...

Thus, the MT wall behaves as an electrical oscillator that produces oscillatory ionic currents with variable amplitude and periodicity depending on the driving force and ionic compositions, and is consistent with the periodic on-off switching of the nanopores.
Click to expand...

https://www.nature.com/articles/s41598-018-30453-2

river · May 2, 2021

Write4U , for the record , we are good .

Write4U said: ↑

Well, you tell me .

All I am trying to suggest in this thread, is that MT may be of primary importance in the emergence of consciousness, by whatever means Electro-Magnetic, Electro-Chemical, Quantum processes.....?

Bundles of Brain Microtubules Generate Electrical Oscillations

Abstract Introduction
https://www.nature.com/articles/s41598-018-30453-2
Click to expand...

Is there any Reason to discontinue your investigation ?

Write4U · May 2, 2021

river said: ↑

Write4U , for the record , we are good.
Click to expand...

If anything, you keep me sharp......
Please Register or Log in to view the hidden image!

Is there any Reason to discontinue your investigation ?
Click to expand...

I am not doing the science, I am just reporting on the science. When I run across something new and exciting I shall post it, no doubt.......
Please Register or Log in to view the hidden image!

Write4U · May 3, 2021

Just ran across this little tidbit about the role of tubulins in Archea.

Archaeal origin of tubulin
Natalya Yutin1 and Eugene V Koonin
Please Register or Log in to view the hidden image!
1

Abstract

Tubulins are a family of GTPases that are key components of the cytoskeleton in all eukaryotes and are distantly related to the FtsZ GTPase that is involved in cell division in most bacteria and many archaea. Among prokaryotes, bona fide tubulins have been identified only in bacteria of the genus Prosthecobacter. These bacterial tubulin genes appear to have been horizontally transferred from eukaryotes. Here we describe tubulins encoded in the genomes of thaumarchaeota of the genus Nitrosoarchaeum that we denote artubulins Phylogenetic analysis results are compatible with the origin of eukaryotic tubulins from artubulins. These findings expand the emerging picture of the origin of key components of eukaryotic functional systems from ancestral forms that are scattered among the extant archaea.
Click to expand...

Findings

Tubulins comprise a distinct family of GTPases that are highly conserved among eukaryotes and are the major components of microtubules, an essential part of the eukaryotic cytoskeleton [1,2]. All eukaryotes encode multiple, paralogous tubulins that evolved through a series of gene duplications at early stages of eukaryote evolution as well as many subsequent, lineage-specific duplications [3]. Among prokaryotes, the only bona fide tubulins have been identified in several bacteria of the genus Prosthecobacter [4] in which they form microtubule-like sturctures closely resembling eukaryotic microtubulues [5]. The tubulins of Prosthecobacteria show high sequence and structural similarity to eukaryotic homologs, and given their extremely narrow distribution among prokaryotes, are thought to have evolved via horizontal transfer of a eukaryotic tubulin gene to an ancestor of this group of bacteria [6,7].
Click to expand...

The great majority of bacteria and many Archaea encode the FtsZ protein which plays a central role in cell division of most bacteria and many archaea and is a prokaryotic homolog of tubulin [8]. Both FtsZ and tubulin undergo GTP- hydrolysis-dependent cycles of polymerization and depolymerization, and are mechanistically analogous [9,10]. However, FtsZ and tubulin share extremely weak sequence similarity, so that the homology has become apparent only through comparison of crystal structures of these proteins [11].
Click to expand...

Recent progress in genome sequencing and comparative genomics has revealed numerous previously unrecognized members of the FtsZ-tubulin protein superfamily [12,13]. These proteins considerably expand the range of sequence divergence adoptable by the FtsZ-tubulin fold but none of them are candidates for the role of direct prokaryotic ancestors of tubulins. In the absence of such candidates, it is generally assumed that tubulin evolved from FtsZ at the onset of eukaryote evolution, and this evolution engendered extreme sequence divergence associated with the shift in function [14].
Click to expand...

Here we describe bona fide tubulins encoded in two recently sequenced genomes of Thaumarchaeota. Phylogenetic analysis suggests that these archaeal tubulins could be the direct ancestors of eukaryotic tubulins, a conclusion that has general implications for the evolution of the key functional systems of the eukaryotic cell.
Click to expand...

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3349469/

IMO, this confirms that microtubules (tubulins) are fundamentally a common denominator in all dynamic life forms and are instrumental in data transport which allows for the dynamic behavior in all animate organisms.

Write4U · May 3, 2021

Additional info about the role of microtubules in muscle function.

Microtubule-dependent transport and organization of sarcomeric myosin during skeletal muscle differentiation
Véronique Pizon,1 Fabien Gerbal,2 Carmen Cifuentes Diaz,3 and Eric Karsenti4,a

Abstract

It has been proposed that microtubules (MTs) participate in skeletal muscle cell differentiation. However, it is still unclear how this happens. To examine whether MTs could participate directly in the organization of thick and thin filaments into sarcomeres, we observed the concomitant reorganization and dynamics of MTs with the behavior of sarcomeric actin and myosin by time-lapse confocal microscopy.
Click to expand...

Using green fluorescent protein (GFP)-EB1 protein to label MT plus ends, we determined that MTs become organized into antiparallel arrays along fusing myotubes. Their dynamics and orientation was found to be different across the thickness of the myotubes. We observed fast movements of Dsred-myosin along GFP-MTs. Comparison of GFP-EB1 and Dsred-myosin dynamics revealed that myosin moved toward MT plus ends.
Click to expand...

Immuno-electron microscopy experiments confirmed that myosin was actually associated with MTs in myotubes. Finally, we confirmed that MTs were required for the stabilization of myosin-containing elements prior to incorporation into mature sarcomeres. Collectively, our results strongly suggest that MTs become organized into a scaffold that provides directional cues for the positioning and organization of myosin filaments during sarcomere formation.
Click to expand...

Keywords: microtubules, muscle differentiation, sarcomeric myosin, transport

Introduction

Skeletal myogenic differentiation involves extensive changes in cell morphology and subcellular architecture. Upon differentiation, myoblasts fuse to form multinucleated syncitia that eventually develop into terminally differentiated muscle cells, the myofibers. Each myofiber is essentially a bundle of myofibrils that provide contractile properties to the whole muscle. A myofibril is built of repeats of contractile units, the sarcomeres. Assembly of contractile proteins into sarcomeres is a complex process that requires polymerization of sarcomeric actin and myosin into thin and thick filaments, remodeling of each polymer into filaments of precise length, and association and alignment of the two filament systems (Craig, 1994). The striking regularity of myosin and actin filaments within the sarcomere is not the result of self-assembly properties of their major constituting proteins, but requires the synthesis and the regulation of numerous muscle proteins expressed during myogenic differentiation, some of them displaying specific interactions with the cytoskeleton lattice (Fürst et al, 1989; Small et al, 1992; Seiler et al, 1996; Ehler et al, 1999).
Click to expand...

In spite of numerous earlier observations, an important and still unsolved question in muscle research concerns the assembly of myosin filaments with opposite polarity into arrays of actin filaments within the sarcomere. Based on the effect of microtubule (MT)-directed drugs, several observations suggest that MTs could participate in the organization of thin and thick filament complexes and in the formation of sarcomeres (Warren, 1968; Goldstein and Entman, 1979; Holtzer et al, 1985; Guo et al, 1986; Saitoh et al, 1988).
Click to expand...

In proliferating myoblasts, a single juxtanuclear centrosome, also called MT organizing center (MTOC) nucleates MTs. In myotubes, the centrosome is eliminated and some MTs that form linear arrays parrallel to the long axis of the cell become detyrosinated, a sign of their increased stability (Gundersen et al, 1989). The importance of MTs for proper myogenesis has been inferred from studies in which myotube formation was aberrant because MTs were either disrupted or stabilized during differentiation (Warren, 1968; Holtzer et al, 1985; Saitoh et al, 1988).
Click to expand...

Therefore, regulation of MT dynamics seems to be of critical importance for myoblast differentiation. In spite of all these observations, little progress has been made on a potential causal relationship between MT organization and dynamics and formation of the sarcomeres. Although descriptive data report on MT network reorganization, no thorough analysis of MT dynamics has been performed so far in living muscle cells.[/quote]

Moreover, research devoted to investigating how muscle-specific proteins are assembled into sarcomeres has been performed mainly with immunofluorescence and electron microscopy experiments. Since myogenic differentiation is an asynchronous event leading to various phenotypes within various differentiating cells as well as within an individual cell, the data obtained could not reflect the ordered spatiotemporal phenomena leading to myofiber formation. In this study, we used fluorescent protein technology and time-lapse dual-wavelength spinning-disk confocal microscopy to analyze the dynamics and organization of MTs and sarcomeric myosin in living myotubes during their differentiation.
Click to expand...

This analysis has revealed that MTs are organized in highly dynamic antiparallel bundles that serve as scaffolding structures to direct the transport and organization of nascent myosin structures in early myotubes. Furthermore, the observation of large numbers of movies showed that, within a myotube, MTs displayed specific compartmentalization, reflected in different dynamics and orientation.
Click to expand...

......more
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1276724/

Write4U · Jun 1, 2021

Paddoboy said; ↑
The proteasome controls ESCRT-III–mediated cell division in an archaeon

Proteasomal control of division in Archaea

In eukaryotes, proteasome-mediated degradation of cell cycle factors triggers mitotic exit, DNA segregation, and cytokinesis, a process that culminates in abscission dependent on the protein ESCRT-III. By studying cell division in an archaeal relative of eukaryotes, Tarrason Risa et al. identified a role for the proteasome in triggering cytokinesis by an archaeal ESCRT-III homolog.
https://www.sciencedirect.com/science/article/pii/S0960982200007466
_____________________________________
Well, lookie what I found!

Microtubules, membranes and cytokinesis
Aaron F.StraightaChristine M.Fielda

Abstract

Proper division of the cell requires coordination between chromosome segregation by the mitotic spindle and cleavage of the cell by the cytokinetic apparatus. Interactions between the mitotic spindle, the contractile ring and the plasma membrane ensure that the cleavage furrow is properly placed between the segregating chromosomes and that new membrane compartments are formed to produce two daughter cells. The microtubule midzone is able to stimulate the cortex of the cell to ensure proper ingression and completion of the cleavage furrow. Specialized microtubule structures are responsible for directing membrane vesicles to the site of cell cleavage, and vesicle fusion is required for the proper completion of cytokinesis.
Click to expand...

Please Register or Log in to view the hidden image!

Please Register or Log in to view the hidden image!

Please Register or Log in to view the hidden image!

Cytokinesis in animal cells can be divided into four stages. First, the cell chooses the site of division during the process known as cleavage plane specification or cleavage site selection. Second, cleavage furrow assembly is characterized by protein recruitment to the site of cell division. Third, ingression or contraction of the cleavage furrow introduces membrane barriers separating the cytoplasm of the daughter cells. Finally, the cleavage furrow seals the membrane compartments forming two new cells in the process of completion or abscission.
Click to expand...

How the cell temporally and spatially coordinates changes in the microtubule cytoskeleton, the actin cytoskeleton and the membrane compartments to accomplish cytokinesis is one of the most interesting problems in cell division.
Click to expand...

........more.
https://www.sciencedirect.com/science/article/pii/S0960982200007466#

Log in or Sign up

Is consciousness to be found in quantum processes in microtubules?

Write4U Valued Senior Member

Google AdSense Guest Advertisement

Write4U Valued Senior Member

Google AdSense Guest Advertisement

Write4U Valued Senior Member

Google AdSense Guest Advertisement

Write4U Valued Senior Member

exchemist Valued Senior Member

billvon Valued Senior Member

Write4U Valued Senior Member

billvon Valued Senior Member

Write4U Valued Senior Member

Write4U Valued Senior Member

Write4U Valued Senior Member

Write4U Valued Senior Member

Write4U Valued Senior Member

river

Write4U Valued Senior Member

river

Write4U Valued Senior Member

Write4U Valued Senior Member

Write4U Valued Senior Member

Write4U Valued Senior Member

Share This Page

Log in or Sign up

Is consciousness to be found in quantum processes in microtubules?

Write4U Valued Senior Member

Google AdSense Guest Advertisement

Write4U Valued Senior Member

Google AdSense Guest Advertisement

Write4U Valued Senior Member

Google AdSense Guest Advertisement

Write4U Valued Senior Member

exchemist Valued Senior Member

billvon Valued Senior Member

Write4U Valued Senior Member

billvon Valued Senior Member

Write4U Valued Senior Member

Write4U Valued Senior Member

Write4U Valued Senior Member

Write4U Valued Senior Member

Write4U Valued Senior Member

river

Write4U Valued Senior Member

river

Write4U Valued Senior Member

Write4U Valued Senior Member

Write4U Valued Senior Member

Write4U Valued Senior Member

Share This Page

Useful Searches