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This article contains a translation of Microtúbulo from es.wikipedia. |
Can there be some paragraph on this. topic.-- 69.150.170.49 ( talk) 10:03, 20 September 2011 (UTC)
http://www.youtube.com/watch?v=NjgBnx1jVIU&feature=related
I had a conversation with a friend of mine this past weekend about this article, and because of the Penrose section he pointed out that this was a perfect example of why Wiki articles really can't be trusted for information beyond pop culture. Frankly that's the last straw for me since I feel like I've added evidence against Penrose as if I'm arguing with him when he really doesn't have any knowledge of microtubules. So I've decided that this information needs to be removed from this article. If anyone disagrees I'd like you to consider moving the section to the article about Penrose, since this theory is more about Penrose's personal philosophies about the nature of consciousness than about any actual scientific studies done on the topic. Kablamo2007 21:27, 26 February 2006 (UTC)
I've removed the section again after it was readded. While Roger Penrose's speculation on quantum consciousness are famous they are in no way authoritative, widely accepted, conform to the evidence, or have ever been empirically tested. In short, don't belong in an encyclopedia. For specifics see my post from a long time ago at the bottom of the talk. If you would like to include the topic in an article on Penrose or his theories then that is the appropriate place. Please, discuss this topic on the talk page before readding the section. 132.162.208.59 Kablamo2007 20:36, 18 October 2006 (UTC)
Perhaps some link to the Orch-OR article would be in order? Any discussion can take place there. I propose this because I wanted to review Penrose's theory and had some trouble locating the Orch-OR article: both this article and the Roger Penrose one didn't link there. I'll fix it for the Penrose one, but leave any modification of this page up to you guys and gals. -- tijmz 14:59, 8 December 2006 (UTC)
Can something be said about the rebuttal of Max Tegmark's argument? I find it unusual that someone would post an isolated rebuttal of Hameroff's calculation, while neglecting what Hameroff has said about Tegmark's calculation. -- DoYouKnow 3:00, 3 January 2007 (UTC)
I'm going to continue to work on this article, I don't research microtubules myself (which is good, because that might skew my vantage point for contributing), but I'm in biology/biochemistry... I separated a "structure" section from "organization" ... I'll be back to work on it more later... The so-called "theory of consciousness" has no business in this article... it should be removed entirely or reduced to a very small statement linking to a stub pertaining to it. IlliniWikipedian 17:34, 19 December 2005 (UTC)
a GDP-bound tubulin in the middle of a microtubule cannot spontaneously pop out.
This is incorrect. Microtubules are known to have the ability to subunit exchange within the polymer, but the occurence of these exchanges are infrequent enough to not endanger the stability of the polymer. -- user:Kablamo2007
Microtubules radiate from the centrosome.
The organization centres that microtubules come from are sometimes called centrosomes, but I think that's more often restricted to the centrioles. These only give rise to microtubules involved in mitotic division, and not those in flagella and axopodia, or those supporting the cell. There could be a connection, but some cells don't even have centrioles, e.g. plants. I'm going to err on the side of caution and remove it unless some better description is given. -- Josh
Actually where a centrosome is present it is the dominant site of microtubule nucleation and it is definitely fair to say that microtubules radiate from the centrosome. The centrosome organises a microtubule array in both mitosis and interphase in animal cells. AND the microtubules of the axoneme are nucleated and organised by the basal body, which is a modified form of the centrosome. The centrioles are a component of both the centrsome and the basal body.
Basal bodies are related to the centrosome, but in most books they aren't the same thing. The centrosome page flatly states that plants don't have centrosomes, and they do have microtubules. As such, making it look like all microtubules come from centrosomes is a mistake.
...however there is growing experimental evidence for a connection between quantum effects in microtubules and the mechanisms of consciousness.
Could we get a reference for this? It really sounds questionable to me. ---
move this to talk.
...however there is growing experimental evidence for a connection between quantum effects in microtubules and the mechanisms of consciousness.
At least mention what the evidence is.
Roadrunner 01:51, 3 Apr 2004 (UTC)
shrinkage vs retraction:
I changed "retraction" to "shrinkage". Depolymerizing microtubules do not usually retract. Depolymerization is the loss of monomers from one end, whereas retraction is a backward movement (or shifting/sliding) of the whole microtubule - an event which is not usually associated with depolymerization. In other words, microtubules can for example depolymerize and protrude at the same time, and it would appear, as if the microtubule would not change at all. However, all kinds of behavior (retraction vs. protrusion and depolymeriztion vs polymerization) can be disected and visualized by a technique called fluorescent speckle microscopy. Another often used expression to describe depolymerizing microtubules is the word "shortening"
This article is categorized under organelles, which microtubules are not. Should we change it? And, oh yeah, the consciousness thing is VERY questionable. -- Delldot 22:48, 8 October 2005 (UTC)
In my view, a hypothesis can only really become part of a pseudoscience if it is not subjected to critical analysis.-- This "view" is clearly wrong--quite a bit of pseudoscience has been subjected to critical analysis. And you seem to be arguing for the opposite--it looks like "not" is a typo--but that too is clearly wrong ... there is vast amounts of pseudoscience that is not taken seriously, for good reason. Also, it's "pseudoscience", not "a pseudoscience"--pseudoscience is rarely organized and coordinated into fields of study the way the sciences are.
There should be...-- no, there shouldn't; that would go against WP policy. There's a single link to Penrose & Hameroff's "theory", which is more than adequate. Jibal ( talk) 19:17, 1 July 2023 (UTC)
1. Microtubules are too large for quantum coherence. The inside of a microtuble is large enough to allow many water molecules and even some drugs such as the cancer medication taxol bind inside the microtubule. Right there is an obvious example of why microtubules don't produce conciousness. If quantum coherence inside the tubule could even occur then someone taking a drug like taxol should exhibit problems with cognitive functions of conscious.
2. While tubulin has two possible conformations, these conformations are not equally likely throught the microtubule. In fact the entirety of the tubule except the outside ring is one state while the outside ring is the other. Without the ability of the microtubule to click through these two states (the 1's and 0's of quantum computing) there is no basis for quantum consciousness.
3. Microtubules are present in all cells and in all eukaryotes. If they are the source of consciousness than why is yeast not conscious in the same sense that we are.
4. Finally, Penrose's argument is only based on the fact that he decided long before picking on the microtubule that consciousness must be a quantum phenomenon. While this may or may not be true, he has targeted the microtubule not out of real understanding of how it functions, but because it was the first thing that he could find that might fit his already formed theory. That's just bad science. Kablamo2007 07:57, 5 November 2005 (UTC)
I strongly object putting a half-cooked theory into a encyclopedia. It has make its way to the textbook first. The molecular or even neuronal nature of consciousness is still a big controversy. Or even the definition of consciousness itself. And I found here stating that it came out of a nanotube? Objection!
11:11, 16 December 2005 (UTC)Jumpingrat
I'd agree with you, but JW Schmidt has said that because of the fame of Penrose that it should be addressed. I would like you to look at my earlier post in the talk about the reasons why it's a crackpot theory. I have yet to try to incorporate them into the article, because they're not something I can really site.... its just what I know is obvious from having undergraduate biology courses. If you could help by writing a good rebuttal paragraph and adding sources I think it would be nice. I do think this article needs to address and firmly rebut Penrose sense I've had a smart friend who's a neuroscience major interested in cognition come to me thinking this theory was "it" and myself having worked with a tubulin-like protein having to explain the reasons why penrose doesn't understand the microtubule. A well written paragraph explaining those points would be good for any readers of Penrose coming here for more information. Kablamo2007 04:34, 25 December 2005 (UTC)
Information is being regularly reverted about this subject, even though one editor actually acknowledges the subject is well known. The subject gets 66,900 Google hits from many proper sources, so there is no reason to continually remove the subject entirely. This will have to go to mediation if other parties continue their blanket removal of the subject. wikipediatrix 00:31, 19 October 2006 (UTC)
Okay, this section currently reads something like "Yeah, it exists, and it's completely wrong". There should be at least a small blurb about what the theory proposes, and any evidence that does in fact support it, if anyone feels qualified to do that. Nathanww 03:00, 22 February 2007 (UTC)
At this time there is no lab science in support of the theory. No microtubule researchers are interested in the topic at all since most don't see how it could work given the present knowledge about microtubules. The current "evidence" for the theory is just the theoretical requirements for quantum coherence which are addressed in the Orch-OR article and as of now there are theoriticians who have said they could never work for the time-scale, size/temperature of microtubules. Besides that fact is that microtubules don't work the way the theory assumes with two equally likely states... the states are not equally likely. I'm fine with the section being tagged... its my opinion that it should go, but it keeps coming back Kablamo2007 16:38, 28 February 2007 (UTC)
I'm just a biology student and I haven't really put any research into this matter, but the section about "Microtubules and consciousness" seems awfully misplaced and I don't understand what it's doing in this article. 130.243.248.239 15:42, 22 March 2007 (UTC)
I think the point is that the Penrose story is pretty much the only logically coherent story of consciousness that science has so far proposed -- sure it's way beyond the fringes and wacky and very very speculative -- but it is the /only/ story we have. Surely every living person on the planet is interested in what consciousness is, and unless they walk away from science altogether and sign up for some religious or new-age fiction then this is the best we currently have to offer. It's wacky, far-fetched, and not accepted by anyone, but its still currently the only, and therefore best, theory we have. —The preceding unsigned comment was added by 84.51.150.211 ( talk) 08:53, 6 April 2007 (UTC).
I think you should mention the Penrose theory and link to another page where a more thorough examination of it can be made aside from this main article on MTs. I would do the same for any other notable past or present theory that relates or refers to the MTs.
I just stumbled over this article looking for some info about microtubules and must say, that the Penrose-part is really irritating. I think you should mention that a theory, not supported by the scientific community exists and link to it, that should keep the conspiracy theory people from deleting it. (I'm not doing it myself as i'm no biochemist and do not really know much about this topic) As for presenting far-fetched, wacky theories as "science", it think that is a really bad idea and i would more likely associate that with new age-fiction than with science. -- 134.76.210.206 08:19, 25 July 2007 (UTC)
The microtubule/quantum consciousness thing has no place here, I've removed it. It is a wild speculation unsupported by anything. The statement that "the Penrose story is pretty much the only logically coherent story of consciousness that science has so far proposed" is absolutely not true (see the Wikipedia page on consciouscness for logically coherent theories of consciousness that are actually supported by evidence). We may as well say here that unicorn horns are made of microtubules. 137.132.243.141 —Preceding comment was added at 03:25, 17 October 2007 (UTC)
I think the article is a bit sparse on describing motor proteins interacting with MT, and should definitely give some space to microtubule associated proteins (MAPS) that can influence the dynamics of microtubules. Such MAPS can favour either a catastrophe or rescue state. Examples of these are numerous, such as XMAP215 (a MT 'polmymerase') and XKCM1 (a MT 'depolymerse'). In general, MT polymerases and depolymerases play important roles in enabling MT dynamics to be altered depending on the requirements of a particular cellular process. —Preceding unsigned comment added by 131.111.244.145 ( talk) 08:12, 12 September 2007 (UTC)
As components of the cytoskeleton, does this mean that microtubules are found only in eukaryotic cells? -- EncycloPetey ( talk) 05:20, 7 January 2009 (UTC)
Microtubules are generally referred to as polar. Is this a polarity in the acid/base sense or merely a recognition of the orientation of subunits? Akita86 ( talk) 17:19, 23 January 2009 (UTC)
I would just like to comment that all of the "citations" for the microtubule entry are garbage. They all cite papers from a very narrow faction of microtubule weirdos (outside of mainstream research), and none is actually a citation of the primary research that originally demonstrated experimentally the particular fact being cited. Citations in scientific articles should cite either the original primary literature or reviews that cite the material, not unrelated primary articles that reference the information in the background or introduction section of the paper.
It appears as if someone from the tribe of "microtubule quantum consciousness" wanted to fool lay readers into believing (1) that they have contributed to the field by discovering some very important basic biological aspects of microtubules (false, these were discovered by others) and (2) their published speculation about quantum consciousness, etc is somehow true and/or commonly accepted (also false).
Just as an example, the microtubule entry correctly states that "the tubulin dimers polymerize end to end in protofilaments," but it cites a 2008 article by Vahid Rezania and Jack A. Tuszynski ("A first principle (3+1) dimensional model for microtubule polymerization"), which is a recent mathematical modeling of microtubule dynamics paper, not the original series of biological experiments that proved this (many years before). The paper cited doesn't prove anything at all, let alone that "tubulin dimers polymerize end to end in protofilaments."
I don't have to continue. The citations are all equally vacuous. Someone with more patience than me should clean it up. Better no citations than false attribution of credit, in my opinion.
I'd hate to believe that peer-review and scholarship in the field are so poor that pseudoscientists are even making a living hallucinating about microtubules, but it might be so... —Preceding unsigned comment added by 69.181.184.55 ( talk) 08:35, 27 May 2009 (UTC)
UPDATE: Another user has changed the citations since the above commentary was posted. The new citations are appropriate. More citations may still be desirable however. —Preceding unsigned comment added by 69.181.184.55 ( talk) 05:34, 1 June 2009 (UTC)
Small but expandible. —Preceding unsigned comment added by 216.186.77.139 ( talk) 17:57, 17 December 2009 (UTC)
So a new section on the Penrose theory has been added to the page. This topic was long the bane of this talk page, and that alone causes me to feel unease at its return. The inclusion of a Microtubules and Consciousness section was debated until its removal on: 20:57, 22 January 2008 by user 198.70.211.246 . In the absence of any newly emerged reasons as to why this section should be a part of this article, I am going to defer to precedent and remove the section. -- AaronM ( talk) 15:28, 23 December 2009 (UTC)
The consciousness section has no place here. I have spent two decades performing research on microtubules and what this page needs is a lot of work, not Penrose pseudoscience. Could a new entry be made were all this quantum consciousness speculation can be stuffed? ( Microtubules ( talk) 01:54, 31 August 2011 (UTC))
I came here looking for information about the quantum effects which they claim supports their theory so that I may evaluate the evidence in a neutral environment. While controversy clearly makes a lot of people's neocortex malfunction there is no reason for why those results too should be censored. - nos 84.248.91.157 ( talk) 19:53, 8 October 2020 (UTC)
The section on "Dynamic mechanism" is an odd one. First, it is unmotivated, incomplete and off-topic. Furthermore, considering the vast literature on MTs, both experimental and theoretical, including reference to this largely esoteric result is really inappropriate. A look at the talk page of the author of the section is informative. It appears as though the author has a habit of self-citation (see the revision history of Graph theory for a good example). Web of Science confirms my impression that the referenced paper is a small fish in a very big pond. Of its 37 citations, the only citing papers that are about MTs are from the consciousness crowd (Hameroff, Tuszynski et al.) which, in my view, does not exactly bolster its relevance here. I removed the section once (readded by AaronM) and will do so again shortly unless someone posts a reasonable defense of it's inclusion. -- Cytryn ( talk) 16:29, 28 August 2010 (UTC)
I think there's an error here: "This complex acts as a scaffold for α/β tubulin dimers to begin polymerization; it acts as a cap of the (−) end while microtubule growth continues away from the MTOC in the (+) direction."
How come the image shows the cap at the + site, whereas it says it's at the - site?
In the image, the green b-tubulin are at the + site, and it says the 2 b-tubulin subunits shown are the cap site. However, in the quotation, it says that the YtRC acts as a cap of the - site, contradicting, thus, the image explanation. Besides, it says this complex acts as a scaffold for POLYMERIZATION [from + site].
I dont get it — Preceding unsigned comment added by 200.106.164.193 ( talk) 01:15, 18 July 2012 (UTC)
It would be good to have a section on Mercury Amalgam and its effects on microtubulin in the brain at low levels (found in those with amalgam fillings). This is on youtube which shows the work of the University of Calgary team as relates to microtubulin in the brain.
AnInformedDude ( talk) 00:42, 10 October 2012 (UTC)
There is a statement in "Postulated role in consciousness" that reads thus:
"While at least one researcher, Michael Persinger, claims otherwise, Jeffrey Gray states ... that tests looking for the influence of electromagnetic fields on brain function have been universally negative in their result."
While I agree that Michael Persinger has shown the influence of magnetic fields on cognition, I am not aware of him making "claims" about consciousness itself. Persinger's experiments have altered the content of consciousness, but as far as I know he does not claim that he is altering the fact that consciousness is present. For this reason, I added a "citation needed" in the text. Timothy Campbell ( talk) 18:30, 17 June 2013 (UTC)
Please can this section be removed from the page. As an active researcher in the microtubule field, I don't see how an unsubstantiated theory that is not well accepted by the scientific community should be included in an encyclopaedia entry. — Preceding unsigned comment added by 133.1.233.36 ( talk) 02:19, 23 July 2013 (UTC)
OK, after going through these two papers, I can summarize what they found and give you an analysis. In Sahu et al., they applied various AC or DC currents to an isolated microtubule and measured conductivity (Figure 2e, f). Microtubules conduct current and there seems to be two types (resistance of 1–10 MΩ and ~300 MΩ). In Figure 3 various electric fields are applied to the MT and the conductance changes, although no rigorous statistics are shown. In Figure 4 the authors claim that changes in applied voltage change the shape of the microtubule as seen under atomic force microscopy. The second paper by Mavromatos is purely theoretical. He claims that microtubule polymers may again adopt two forms (analogous I suppose to the two conductive forms) and goes over some ideas of conductance and integrates this with models that the microtubule lattice may help to order water in the microtubule lumen.
Leaving aside some of the factual errors in each paper (microtubules did not appear 3.5 million years ago, there is no Ca2+ imbedded in the microtubule protofilaments ...),
I would say that the authors of the first manuscript provide some data supporting the idea that microtubules have some electrical properties (however other groups have also shown this) and these properties may display some features that depend on dipole moments that may be in some entangled state. So what? How does this translate to any physiological effects? How does it impinge on neuronal behavior?
You're making these discoveries a great deal less important than it really seems.
If these effects are used to perform computations, how does data input occur in vivo (what is the source of the data? what writes the data?) and then how is the output read in vivo. The authors do not even attempt to come up with a plausible scenario for how biological molecules perform data input/output on microtubules.
In contrast Mavromatos points to other systems where quantum effects do play a role in biological processes. For example in photosynthetic process, where we have an exact understanding of how energy states are transferred between molecules and how this is leads to the production of a proton gradient across a membrane. The gradient is then disipated by F1 ATPase to regenerate ATP. In this case, the underlying mechanism is clear – quantum states translate to the movement of protons. However I am puzzled by the statements being made with respect to microtubule function, such as microtubules “compute”. What does this mean? What is the mechanism that reads and writes? How could this possibly affect physiology? In short, there is no there there. Indeed Navromatos writes “I believe that very interesting future experiments can be done with MT, which could shed light on the above aspects of MT as quantum devices, which presently belong to the realm of science fiction.”
So all of this work is very speculative, and I do not think that the few investigators studying quantum effects on microtubule function have made a compelling case for their physiological relevance. In contrast, many more labs are investigating the post-translational modification of microtubules (for a recent review see Janke & Bulinsky in Nature Rev MCB (2011) - with 186 references, http://www.fbmc.fcen.uba.ar/materias/qbiia/teoricos-2012/teorica-4-bibliografia-de-apoyo-de-graciela-bocaccio/micotub%20PTM%20by%20cloe%20bulinsky.pdf), yet until yesterday this extremely active area of research was not even mentioned on the microtubule page. Microtubule modifications are known to affect how motors interact with tubulin and how organelles are transported along the microtubules. In this case there is physiological relevance. And findings from this very active area are published in Science ( http://www.ncbi.nlm.nih.gov/pubmed/15890843), Nature ( http://www.ncbi.nlm.nih.gov/pubmed/12024216) and Cell ( http://www.ncbi.nlm.nih.gov/pubmed/19524510)! I point this out to contrast the two fields, the first is speculative and thus far does not seem to be conected to physiological relevance (but was included on the microtubule page), the second is a very active field (but until yesterday was not even mentioned). Microtubules ( talk) 21:57, 6 August 2013 (UTC)
Wikipedia is also not a crystal ball: While currently accepted scientific paradigms may later be rejected, and hypotheses previously held to be controversial or incorrect sometimes become accepted by the scientific community (e.g., plate tectonics), it is not the place of Wikipedia to venture such projections. If the status of a given idea changes, then Wikipedia changes to reflect that change. Wikipedia primarily focuses on the state of knowledge today, documenting the past when appropriate (identifying it as such), and avoiding speculation about the future.
This is not a place to discuss the scientific merits of Orch-OR. This is an issue of scientific acceptance, and under WP:NPOV, Orch-OR cannot be mentioned in this article.
Orch-OR departs from mainstream science, and has little scientific support; it is classifiable as a fringe theory in science under WP:FRINGE, and subject to heightened scrutiny. From WP:FRINGE#Mention in other articles,
In this context, a reliable secondary or tertiary source is required. An acceptable source would be a review article on recent microtubule work in Nature Reviews Molecular Cell Biology that positively highlights Orch-OR's direct implications to the field, or an undergraduate textbook on cell biology that mentions Orch-OR in a serious fashion in connection with microtubules.
There exist no reliable WP:secondary or WP:tertiary sources that do this. Therefore, per WP:ONEWAY, a decent article on microtubules should not mention Orch-OR. — wing gundam 02:05, 7 August 2013 (UTC)
I'm really impressed with Microtubules', 24.192.195.236's and wing gundam's dedication to this discussion. The last time I commented on this talk page, I considered commenting on the Penrose material but noticed how intense people seem to get about it so I dropped it to avoid wasting a bunch of time. Given that Microtubules picked up the banner, I figure I may as well chime in. I've read a bit of Penrose's work (The Emperor's New Mind) but not much about his theories of microtubules and consciousness. As someone who works on modeling of microtubules and FtsZ in cell division, almost entirely theoretical, I can say that I strongly agree with Microtubules concerning the value of models and theories. They are a dime a dozen and should not be included in an encyclopedia article simply because someone famous proposes or endorses them or because they generate controversy in the realm of popularized science. Substantiation is essential. Sure, a controversial topic has a place in an encyclodepia - in an article about the primary topic (e.g. Orch-OR) but not in an article on one of the players invoked in the theory. As to whether Orch-OR is one such theory, consider the principle that "extraordinary claims require extraordinary proof". Orch-OR strikes me as a classic extraordinary theory. It would not attract the interest of non-scientists in the way it does nor would it fail to attract the interest of scientists the way it does if it weren't. I haven't read enough to weaken the adjective on "proof" but it's clear from the few sources I've looked at so far that extraordinary proof is definitely lacking. As such, including reference to it in the articles about its component parts is inappropriate. -- Cytryn ( talk) 23:06, 7 August 2013 (UTC)
Summarizing the consensus opinion, we find that
Orch-OR cannot be mentioned in the
Microtubule article. Pursuant to this, we hold that the section #Postulated role in consciousness should not be reintroduced. While Orch-OR may turn out to have scientific validitysome basis in reality,
that is not for us to judge. We merely document the
established views of the
scientific community, wherein we note Orch-OR is an unproven minority viewpoint and consequentially the subject matter of
WP:FRINGE.
As User:Microtubules and User:Cytryn argued, there are many hypothetical models for microtubules, including Penrose/Hameroff's ideas, cytoskeletal tensegrity, tubulin healing, microtubule luminal transport, and others equally speculative. Models like these are "a dime a dozen". To be mentioned in this article, an independently reviewed secondary or tertiary source must directly connect microtubules to some particular model. (e.g. a review article in Nature Reviews Molecular Cell Biology, a critically reviewed textbook on cell biology, a mention in Nature's cytoskeletal milestones). There exist no such sources for Orch-OR. Thus, it would be a violation of WP:NPOV for Microtubule to include any discussion of Orch-OR, however minor.
— wing gundam 01:48, 9 August 2013 (UTC)
I did a major edit of the section on organization during cell division. I hope I got the centromere/centriole thing correct (had no idea about that before I read the talk page!); feel free to correct that if I got it wrong. Also, I'm not entirely sure I got it right about polar microtubules. From the article on centromeres, it seems like there's a type of microtubule called the polar microtubule which assists in cell division, but there's also the fact that all microtubules are considered to be polar due to the end-to-end orientation of the dimers. And of course both of those definitions have nothing to do with the polarity that exists in some molecules such as water. It's very confusing! Jojojlj ( talk) 07:13, 21 October 2013 (UTC)
This section seems a little out of place and not in keeping with the rest of the article. It's a list of biophysical facts directly taken from one or two papers with no context in particular to any biological application. I appreciate that other researchers might be looking at microtubules as structures for the development of new computing architectures or explanations for the information processing capacity of the human brain. Yet these viewpoints are held by a minority and I don't believe that an encyclopaedia article should be carrying information on current research that is a minority viewpoint.
Its well known to researchers in the field that the electrostatic properties of tubulin/microtubules are considered to underlie their interactions with various proteins such as MAPs and motors.
Perhaps a section of the physiochemical properties of microtubules/tubulin would better idea?
There is an image with the legend as follows: "This image shows two components of the cytoskeleton, microtubules (green) and actin filaments (red), in an endothelial cell derived from a cow lung. The cystoskeleton provides the cell with an inner framework and enables it to move and change shape."
In my opinion the legend is incorrect. The green structures on this image look like actin fibers, and the red structures look like mitochondria.
-- Eszcze ( talk) 13:24, 1 March 2015 (UTC)
Okay, I started a request for deletion here. SPLETTE :] How's my driving? 13:05, 18 June 2015 (UTC)
Unless so few people know about it. Socialistguy ( talk) 17:33, 25 February 2016 (UTC)
The comment(s) below were originally left at Talk:Microtubule/Comments, and are posted here for posterity. Following several discussions in past years, these subpages are now deprecated. The comments may be irrelevant or outdated; if so, please feel free to remove this section.
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I would just like to comment that all of the "citations" for the microtubule entry are garbage. They all cite papers from a very narrow faction of microtubule weirdos (outside of mainstream research), and none is actually a citation of the primary research that originally demonstrated experimentally the particular fact being cited.
It appears as if someone from the tribe of "microtubule quantum consciousness" wanted to fool lay readers into believing (1) that they have contributed to the field by discovering some very important basic biological aspects of microtubules (false, these were discovered by others) and (2) their published speculation about quantum consciousness, etc is somehow true and/or commonly accepted. Just as an example, the entry correctly states that "the tubulin dimers polymerize end to end in protofilaments," but it cites a 2008 article by Vahid Rezania and Jack A. Tuszynski ("A first principle (3+1) dimensional model for microtubule polymerization"), which is a mathematical modeling of microtubule dynamics paper, not a series of biological experiments. The paper doesn't prove anything at all, let alone that "tubulin dimers polymerize end to end in protofilaments" I don't have to continue. The citations are all equally vacuous. I hate to believe that peer-review and scholarship in the field are so poor that pseudoscientists can even make a living hallucinating about microtubules, but it might be so... |
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The article begins with this sentence:
We can assume that whoever came to read this articles wants to know what microtubules are.
So including the etymology of the word in the first sentence is overloading the sentence with too much extraneous information too soon. (Sure, the etymology is a good thing to include, but not before the reader knows what the word means.)
Next we get to the word "component" which most high school students know, but younger children may not. Why use an unnecessarily advanced word when a word like "portion" or "part" will work?
Then we get to the two worst aspects of this sentence by far: two words — "cytoskeleton" and "cytoplasm" — that are highly unlikely to be in any reader's vocabulary. (Unless of course they are in the small fraction of readers who happen to know the word.)
Such words are entirely inappropriate for an introductory part of an article, and especially the first sentence, above all when simpler words can be used. That is surely true. Do not make the reader click on links in order to know what you are talking about, especially in the very first sentence. There are five links in this first sentence!
I hope the first sentence and paragraph are rewritten by someone knowledgeable about the subject, so that most 9-year-old children can understand it. I see no reason why that could not be the case. 108.245.209.39 ( talk) 21:14, 14 June 2018 (UTC)
Am I blind, or the information that the diameter of microtubules is 24 nm is not stated in the cited article? https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3232192 — Preceding unsigned comment added by Vašek Bočan ( talk • contribs) 10:01, 22 March 2019 (UTC)
This
level-5 vital article is rated B-class on Wikipedia's
content assessment scale. It is of interest to the following WikiProjects: | ||||||||||||||
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This article contains a translation of Microtúbulo from es.wikipedia. |
Can there be some paragraph on this. topic.-- 69.150.170.49 ( talk) 10:03, 20 September 2011 (UTC)
http://www.youtube.com/watch?v=NjgBnx1jVIU&feature=related
I had a conversation with a friend of mine this past weekend about this article, and because of the Penrose section he pointed out that this was a perfect example of why Wiki articles really can't be trusted for information beyond pop culture. Frankly that's the last straw for me since I feel like I've added evidence against Penrose as if I'm arguing with him when he really doesn't have any knowledge of microtubules. So I've decided that this information needs to be removed from this article. If anyone disagrees I'd like you to consider moving the section to the article about Penrose, since this theory is more about Penrose's personal philosophies about the nature of consciousness than about any actual scientific studies done on the topic. Kablamo2007 21:27, 26 February 2006 (UTC)
I've removed the section again after it was readded. While Roger Penrose's speculation on quantum consciousness are famous they are in no way authoritative, widely accepted, conform to the evidence, or have ever been empirically tested. In short, don't belong in an encyclopedia. For specifics see my post from a long time ago at the bottom of the talk. If you would like to include the topic in an article on Penrose or his theories then that is the appropriate place. Please, discuss this topic on the talk page before readding the section. 132.162.208.59 Kablamo2007 20:36, 18 October 2006 (UTC)
Perhaps some link to the Orch-OR article would be in order? Any discussion can take place there. I propose this because I wanted to review Penrose's theory and had some trouble locating the Orch-OR article: both this article and the Roger Penrose one didn't link there. I'll fix it for the Penrose one, but leave any modification of this page up to you guys and gals. -- tijmz 14:59, 8 December 2006 (UTC)
Can something be said about the rebuttal of Max Tegmark's argument? I find it unusual that someone would post an isolated rebuttal of Hameroff's calculation, while neglecting what Hameroff has said about Tegmark's calculation. -- DoYouKnow 3:00, 3 January 2007 (UTC)
I'm going to continue to work on this article, I don't research microtubules myself (which is good, because that might skew my vantage point for contributing), but I'm in biology/biochemistry... I separated a "structure" section from "organization" ... I'll be back to work on it more later... The so-called "theory of consciousness" has no business in this article... it should be removed entirely or reduced to a very small statement linking to a stub pertaining to it. IlliniWikipedian 17:34, 19 December 2005 (UTC)
a GDP-bound tubulin in the middle of a microtubule cannot spontaneously pop out.
This is incorrect. Microtubules are known to have the ability to subunit exchange within the polymer, but the occurence of these exchanges are infrequent enough to not endanger the stability of the polymer. -- user:Kablamo2007
Microtubules radiate from the centrosome.
The organization centres that microtubules come from are sometimes called centrosomes, but I think that's more often restricted to the centrioles. These only give rise to microtubules involved in mitotic division, and not those in flagella and axopodia, or those supporting the cell. There could be a connection, but some cells don't even have centrioles, e.g. plants. I'm going to err on the side of caution and remove it unless some better description is given. -- Josh
Actually where a centrosome is present it is the dominant site of microtubule nucleation and it is definitely fair to say that microtubules radiate from the centrosome. The centrosome organises a microtubule array in both mitosis and interphase in animal cells. AND the microtubules of the axoneme are nucleated and organised by the basal body, which is a modified form of the centrosome. The centrioles are a component of both the centrsome and the basal body.
Basal bodies are related to the centrosome, but in most books they aren't the same thing. The centrosome page flatly states that plants don't have centrosomes, and they do have microtubules. As such, making it look like all microtubules come from centrosomes is a mistake.
...however there is growing experimental evidence for a connection between quantum effects in microtubules and the mechanisms of consciousness.
Could we get a reference for this? It really sounds questionable to me. ---
move this to talk.
...however there is growing experimental evidence for a connection between quantum effects in microtubules and the mechanisms of consciousness.
At least mention what the evidence is.
Roadrunner 01:51, 3 Apr 2004 (UTC)
shrinkage vs retraction:
I changed "retraction" to "shrinkage". Depolymerizing microtubules do not usually retract. Depolymerization is the loss of monomers from one end, whereas retraction is a backward movement (or shifting/sliding) of the whole microtubule - an event which is not usually associated with depolymerization. In other words, microtubules can for example depolymerize and protrude at the same time, and it would appear, as if the microtubule would not change at all. However, all kinds of behavior (retraction vs. protrusion and depolymeriztion vs polymerization) can be disected and visualized by a technique called fluorescent speckle microscopy. Another often used expression to describe depolymerizing microtubules is the word "shortening"
This article is categorized under organelles, which microtubules are not. Should we change it? And, oh yeah, the consciousness thing is VERY questionable. -- Delldot 22:48, 8 October 2005 (UTC)
In my view, a hypothesis can only really become part of a pseudoscience if it is not subjected to critical analysis.-- This "view" is clearly wrong--quite a bit of pseudoscience has been subjected to critical analysis. And you seem to be arguing for the opposite--it looks like "not" is a typo--but that too is clearly wrong ... there is vast amounts of pseudoscience that is not taken seriously, for good reason. Also, it's "pseudoscience", not "a pseudoscience"--pseudoscience is rarely organized and coordinated into fields of study the way the sciences are.
There should be...-- no, there shouldn't; that would go against WP policy. There's a single link to Penrose & Hameroff's "theory", which is more than adequate. Jibal ( talk) 19:17, 1 July 2023 (UTC)
1. Microtubules are too large for quantum coherence. The inside of a microtuble is large enough to allow many water molecules and even some drugs such as the cancer medication taxol bind inside the microtubule. Right there is an obvious example of why microtubules don't produce conciousness. If quantum coherence inside the tubule could even occur then someone taking a drug like taxol should exhibit problems with cognitive functions of conscious.
2. While tubulin has two possible conformations, these conformations are not equally likely throught the microtubule. In fact the entirety of the tubule except the outside ring is one state while the outside ring is the other. Without the ability of the microtubule to click through these two states (the 1's and 0's of quantum computing) there is no basis for quantum consciousness.
3. Microtubules are present in all cells and in all eukaryotes. If they are the source of consciousness than why is yeast not conscious in the same sense that we are.
4. Finally, Penrose's argument is only based on the fact that he decided long before picking on the microtubule that consciousness must be a quantum phenomenon. While this may or may not be true, he has targeted the microtubule not out of real understanding of how it functions, but because it was the first thing that he could find that might fit his already formed theory. That's just bad science. Kablamo2007 07:57, 5 November 2005 (UTC)
I strongly object putting a half-cooked theory into a encyclopedia. It has make its way to the textbook first. The molecular or even neuronal nature of consciousness is still a big controversy. Or even the definition of consciousness itself. And I found here stating that it came out of a nanotube? Objection!
11:11, 16 December 2005 (UTC)Jumpingrat
I'd agree with you, but JW Schmidt has said that because of the fame of Penrose that it should be addressed. I would like you to look at my earlier post in the talk about the reasons why it's a crackpot theory. I have yet to try to incorporate them into the article, because they're not something I can really site.... its just what I know is obvious from having undergraduate biology courses. If you could help by writing a good rebuttal paragraph and adding sources I think it would be nice. I do think this article needs to address and firmly rebut Penrose sense I've had a smart friend who's a neuroscience major interested in cognition come to me thinking this theory was "it" and myself having worked with a tubulin-like protein having to explain the reasons why penrose doesn't understand the microtubule. A well written paragraph explaining those points would be good for any readers of Penrose coming here for more information. Kablamo2007 04:34, 25 December 2005 (UTC)
Information is being regularly reverted about this subject, even though one editor actually acknowledges the subject is well known. The subject gets 66,900 Google hits from many proper sources, so there is no reason to continually remove the subject entirely. This will have to go to mediation if other parties continue their blanket removal of the subject. wikipediatrix 00:31, 19 October 2006 (UTC)
Okay, this section currently reads something like "Yeah, it exists, and it's completely wrong". There should be at least a small blurb about what the theory proposes, and any evidence that does in fact support it, if anyone feels qualified to do that. Nathanww 03:00, 22 February 2007 (UTC)
At this time there is no lab science in support of the theory. No microtubule researchers are interested in the topic at all since most don't see how it could work given the present knowledge about microtubules. The current "evidence" for the theory is just the theoretical requirements for quantum coherence which are addressed in the Orch-OR article and as of now there are theoriticians who have said they could never work for the time-scale, size/temperature of microtubules. Besides that fact is that microtubules don't work the way the theory assumes with two equally likely states... the states are not equally likely. I'm fine with the section being tagged... its my opinion that it should go, but it keeps coming back Kablamo2007 16:38, 28 February 2007 (UTC)
I'm just a biology student and I haven't really put any research into this matter, but the section about "Microtubules and consciousness" seems awfully misplaced and I don't understand what it's doing in this article. 130.243.248.239 15:42, 22 March 2007 (UTC)
I think the point is that the Penrose story is pretty much the only logically coherent story of consciousness that science has so far proposed -- sure it's way beyond the fringes and wacky and very very speculative -- but it is the /only/ story we have. Surely every living person on the planet is interested in what consciousness is, and unless they walk away from science altogether and sign up for some religious or new-age fiction then this is the best we currently have to offer. It's wacky, far-fetched, and not accepted by anyone, but its still currently the only, and therefore best, theory we have. —The preceding unsigned comment was added by 84.51.150.211 ( talk) 08:53, 6 April 2007 (UTC).
I think you should mention the Penrose theory and link to another page where a more thorough examination of it can be made aside from this main article on MTs. I would do the same for any other notable past or present theory that relates or refers to the MTs.
I just stumbled over this article looking for some info about microtubules and must say, that the Penrose-part is really irritating. I think you should mention that a theory, not supported by the scientific community exists and link to it, that should keep the conspiracy theory people from deleting it. (I'm not doing it myself as i'm no biochemist and do not really know much about this topic) As for presenting far-fetched, wacky theories as "science", it think that is a really bad idea and i would more likely associate that with new age-fiction than with science. -- 134.76.210.206 08:19, 25 July 2007 (UTC)
The microtubule/quantum consciousness thing has no place here, I've removed it. It is a wild speculation unsupported by anything. The statement that "the Penrose story is pretty much the only logically coherent story of consciousness that science has so far proposed" is absolutely not true (see the Wikipedia page on consciouscness for logically coherent theories of consciousness that are actually supported by evidence). We may as well say here that unicorn horns are made of microtubules. 137.132.243.141 —Preceding comment was added at 03:25, 17 October 2007 (UTC)
I think the article is a bit sparse on describing motor proteins interacting with MT, and should definitely give some space to microtubule associated proteins (MAPS) that can influence the dynamics of microtubules. Such MAPS can favour either a catastrophe or rescue state. Examples of these are numerous, such as XMAP215 (a MT 'polmymerase') and XKCM1 (a MT 'depolymerse'). In general, MT polymerases and depolymerases play important roles in enabling MT dynamics to be altered depending on the requirements of a particular cellular process. —Preceding unsigned comment added by 131.111.244.145 ( talk) 08:12, 12 September 2007 (UTC)
As components of the cytoskeleton, does this mean that microtubules are found only in eukaryotic cells? -- EncycloPetey ( talk) 05:20, 7 January 2009 (UTC)
Microtubules are generally referred to as polar. Is this a polarity in the acid/base sense or merely a recognition of the orientation of subunits? Akita86 ( talk) 17:19, 23 January 2009 (UTC)
I would just like to comment that all of the "citations" for the microtubule entry are garbage. They all cite papers from a very narrow faction of microtubule weirdos (outside of mainstream research), and none is actually a citation of the primary research that originally demonstrated experimentally the particular fact being cited. Citations in scientific articles should cite either the original primary literature or reviews that cite the material, not unrelated primary articles that reference the information in the background or introduction section of the paper.
It appears as if someone from the tribe of "microtubule quantum consciousness" wanted to fool lay readers into believing (1) that they have contributed to the field by discovering some very important basic biological aspects of microtubules (false, these were discovered by others) and (2) their published speculation about quantum consciousness, etc is somehow true and/or commonly accepted (also false).
Just as an example, the microtubule entry correctly states that "the tubulin dimers polymerize end to end in protofilaments," but it cites a 2008 article by Vahid Rezania and Jack A. Tuszynski ("A first principle (3+1) dimensional model for microtubule polymerization"), which is a recent mathematical modeling of microtubule dynamics paper, not the original series of biological experiments that proved this (many years before). The paper cited doesn't prove anything at all, let alone that "tubulin dimers polymerize end to end in protofilaments."
I don't have to continue. The citations are all equally vacuous. Someone with more patience than me should clean it up. Better no citations than false attribution of credit, in my opinion.
I'd hate to believe that peer-review and scholarship in the field are so poor that pseudoscientists are even making a living hallucinating about microtubules, but it might be so... —Preceding unsigned comment added by 69.181.184.55 ( talk) 08:35, 27 May 2009 (UTC)
UPDATE: Another user has changed the citations since the above commentary was posted. The new citations are appropriate. More citations may still be desirable however. —Preceding unsigned comment added by 69.181.184.55 ( talk) 05:34, 1 June 2009 (UTC)
Small but expandible. —Preceding unsigned comment added by 216.186.77.139 ( talk) 17:57, 17 December 2009 (UTC)
So a new section on the Penrose theory has been added to the page. This topic was long the bane of this talk page, and that alone causes me to feel unease at its return. The inclusion of a Microtubules and Consciousness section was debated until its removal on: 20:57, 22 January 2008 by user 198.70.211.246 . In the absence of any newly emerged reasons as to why this section should be a part of this article, I am going to defer to precedent and remove the section. -- AaronM ( talk) 15:28, 23 December 2009 (UTC)
The consciousness section has no place here. I have spent two decades performing research on microtubules and what this page needs is a lot of work, not Penrose pseudoscience. Could a new entry be made were all this quantum consciousness speculation can be stuffed? ( Microtubules ( talk) 01:54, 31 August 2011 (UTC))
I came here looking for information about the quantum effects which they claim supports their theory so that I may evaluate the evidence in a neutral environment. While controversy clearly makes a lot of people's neocortex malfunction there is no reason for why those results too should be censored. - nos 84.248.91.157 ( talk) 19:53, 8 October 2020 (UTC)
The section on "Dynamic mechanism" is an odd one. First, it is unmotivated, incomplete and off-topic. Furthermore, considering the vast literature on MTs, both experimental and theoretical, including reference to this largely esoteric result is really inappropriate. A look at the talk page of the author of the section is informative. It appears as though the author has a habit of self-citation (see the revision history of Graph theory for a good example). Web of Science confirms my impression that the referenced paper is a small fish in a very big pond. Of its 37 citations, the only citing papers that are about MTs are from the consciousness crowd (Hameroff, Tuszynski et al.) which, in my view, does not exactly bolster its relevance here. I removed the section once (readded by AaronM) and will do so again shortly unless someone posts a reasonable defense of it's inclusion. -- Cytryn ( talk) 16:29, 28 August 2010 (UTC)
I think there's an error here: "This complex acts as a scaffold for α/β tubulin dimers to begin polymerization; it acts as a cap of the (−) end while microtubule growth continues away from the MTOC in the (+) direction."
How come the image shows the cap at the + site, whereas it says it's at the - site?
In the image, the green b-tubulin are at the + site, and it says the 2 b-tubulin subunits shown are the cap site. However, in the quotation, it says that the YtRC acts as a cap of the - site, contradicting, thus, the image explanation. Besides, it says this complex acts as a scaffold for POLYMERIZATION [from + site].
I dont get it — Preceding unsigned comment added by 200.106.164.193 ( talk) 01:15, 18 July 2012 (UTC)
It would be good to have a section on Mercury Amalgam and its effects on microtubulin in the brain at low levels (found in those with amalgam fillings). This is on youtube which shows the work of the University of Calgary team as relates to microtubulin in the brain.
AnInformedDude ( talk) 00:42, 10 October 2012 (UTC)
There is a statement in "Postulated role in consciousness" that reads thus:
"While at least one researcher, Michael Persinger, claims otherwise, Jeffrey Gray states ... that tests looking for the influence of electromagnetic fields on brain function have been universally negative in their result."
While I agree that Michael Persinger has shown the influence of magnetic fields on cognition, I am not aware of him making "claims" about consciousness itself. Persinger's experiments have altered the content of consciousness, but as far as I know he does not claim that he is altering the fact that consciousness is present. For this reason, I added a "citation needed" in the text. Timothy Campbell ( talk) 18:30, 17 June 2013 (UTC)
Please can this section be removed from the page. As an active researcher in the microtubule field, I don't see how an unsubstantiated theory that is not well accepted by the scientific community should be included in an encyclopaedia entry. — Preceding unsigned comment added by 133.1.233.36 ( talk) 02:19, 23 July 2013 (UTC)
OK, after going through these two papers, I can summarize what they found and give you an analysis. In Sahu et al., they applied various AC or DC currents to an isolated microtubule and measured conductivity (Figure 2e, f). Microtubules conduct current and there seems to be two types (resistance of 1–10 MΩ and ~300 MΩ). In Figure 3 various electric fields are applied to the MT and the conductance changes, although no rigorous statistics are shown. In Figure 4 the authors claim that changes in applied voltage change the shape of the microtubule as seen under atomic force microscopy. The second paper by Mavromatos is purely theoretical. He claims that microtubule polymers may again adopt two forms (analogous I suppose to the two conductive forms) and goes over some ideas of conductance and integrates this with models that the microtubule lattice may help to order water in the microtubule lumen.
Leaving aside some of the factual errors in each paper (microtubules did not appear 3.5 million years ago, there is no Ca2+ imbedded in the microtubule protofilaments ...),
I would say that the authors of the first manuscript provide some data supporting the idea that microtubules have some electrical properties (however other groups have also shown this) and these properties may display some features that depend on dipole moments that may be in some entangled state. So what? How does this translate to any physiological effects? How does it impinge on neuronal behavior?
You're making these discoveries a great deal less important than it really seems.
If these effects are used to perform computations, how does data input occur in vivo (what is the source of the data? what writes the data?) and then how is the output read in vivo. The authors do not even attempt to come up with a plausible scenario for how biological molecules perform data input/output on microtubules.
In contrast Mavromatos points to other systems where quantum effects do play a role in biological processes. For example in photosynthetic process, where we have an exact understanding of how energy states are transferred between molecules and how this is leads to the production of a proton gradient across a membrane. The gradient is then disipated by F1 ATPase to regenerate ATP. In this case, the underlying mechanism is clear – quantum states translate to the movement of protons. However I am puzzled by the statements being made with respect to microtubule function, such as microtubules “compute”. What does this mean? What is the mechanism that reads and writes? How could this possibly affect physiology? In short, there is no there there. Indeed Navromatos writes “I believe that very interesting future experiments can be done with MT, which could shed light on the above aspects of MT as quantum devices, which presently belong to the realm of science fiction.”
So all of this work is very speculative, and I do not think that the few investigators studying quantum effects on microtubule function have made a compelling case for their physiological relevance. In contrast, many more labs are investigating the post-translational modification of microtubules (for a recent review see Janke & Bulinsky in Nature Rev MCB (2011) - with 186 references, http://www.fbmc.fcen.uba.ar/materias/qbiia/teoricos-2012/teorica-4-bibliografia-de-apoyo-de-graciela-bocaccio/micotub%20PTM%20by%20cloe%20bulinsky.pdf), yet until yesterday this extremely active area of research was not even mentioned on the microtubule page. Microtubule modifications are known to affect how motors interact with tubulin and how organelles are transported along the microtubules. In this case there is physiological relevance. And findings from this very active area are published in Science ( http://www.ncbi.nlm.nih.gov/pubmed/15890843), Nature ( http://www.ncbi.nlm.nih.gov/pubmed/12024216) and Cell ( http://www.ncbi.nlm.nih.gov/pubmed/19524510)! I point this out to contrast the two fields, the first is speculative and thus far does not seem to be conected to physiological relevance (but was included on the microtubule page), the second is a very active field (but until yesterday was not even mentioned). Microtubules ( talk) 21:57, 6 August 2013 (UTC)
Wikipedia is also not a crystal ball: While currently accepted scientific paradigms may later be rejected, and hypotheses previously held to be controversial or incorrect sometimes become accepted by the scientific community (e.g., plate tectonics), it is not the place of Wikipedia to venture such projections. If the status of a given idea changes, then Wikipedia changes to reflect that change. Wikipedia primarily focuses on the state of knowledge today, documenting the past when appropriate (identifying it as such), and avoiding speculation about the future.
This is not a place to discuss the scientific merits of Orch-OR. This is an issue of scientific acceptance, and under WP:NPOV, Orch-OR cannot be mentioned in this article.
Orch-OR departs from mainstream science, and has little scientific support; it is classifiable as a fringe theory in science under WP:FRINGE, and subject to heightened scrutiny. From WP:FRINGE#Mention in other articles,
In this context, a reliable secondary or tertiary source is required. An acceptable source would be a review article on recent microtubule work in Nature Reviews Molecular Cell Biology that positively highlights Orch-OR's direct implications to the field, or an undergraduate textbook on cell biology that mentions Orch-OR in a serious fashion in connection with microtubules.
There exist no reliable WP:secondary or WP:tertiary sources that do this. Therefore, per WP:ONEWAY, a decent article on microtubules should not mention Orch-OR. — wing gundam 02:05, 7 August 2013 (UTC)
I'm really impressed with Microtubules', 24.192.195.236's and wing gundam's dedication to this discussion. The last time I commented on this talk page, I considered commenting on the Penrose material but noticed how intense people seem to get about it so I dropped it to avoid wasting a bunch of time. Given that Microtubules picked up the banner, I figure I may as well chime in. I've read a bit of Penrose's work (The Emperor's New Mind) but not much about his theories of microtubules and consciousness. As someone who works on modeling of microtubules and FtsZ in cell division, almost entirely theoretical, I can say that I strongly agree with Microtubules concerning the value of models and theories. They are a dime a dozen and should not be included in an encyclopedia article simply because someone famous proposes or endorses them or because they generate controversy in the realm of popularized science. Substantiation is essential. Sure, a controversial topic has a place in an encyclodepia - in an article about the primary topic (e.g. Orch-OR) but not in an article on one of the players invoked in the theory. As to whether Orch-OR is one such theory, consider the principle that "extraordinary claims require extraordinary proof". Orch-OR strikes me as a classic extraordinary theory. It would not attract the interest of non-scientists in the way it does nor would it fail to attract the interest of scientists the way it does if it weren't. I haven't read enough to weaken the adjective on "proof" but it's clear from the few sources I've looked at so far that extraordinary proof is definitely lacking. As such, including reference to it in the articles about its component parts is inappropriate. -- Cytryn ( talk) 23:06, 7 August 2013 (UTC)
Summarizing the consensus opinion, we find that
Orch-OR cannot be mentioned in the
Microtubule article. Pursuant to this, we hold that the section #Postulated role in consciousness should not be reintroduced. While Orch-OR may turn out to have scientific validitysome basis in reality,
that is not for us to judge. We merely document the
established views of the
scientific community, wherein we note Orch-OR is an unproven minority viewpoint and consequentially the subject matter of
WP:FRINGE.
As User:Microtubules and User:Cytryn argued, there are many hypothetical models for microtubules, including Penrose/Hameroff's ideas, cytoskeletal tensegrity, tubulin healing, microtubule luminal transport, and others equally speculative. Models like these are "a dime a dozen". To be mentioned in this article, an independently reviewed secondary or tertiary source must directly connect microtubules to some particular model. (e.g. a review article in Nature Reviews Molecular Cell Biology, a critically reviewed textbook on cell biology, a mention in Nature's cytoskeletal milestones). There exist no such sources for Orch-OR. Thus, it would be a violation of WP:NPOV for Microtubule to include any discussion of Orch-OR, however minor.
— wing gundam 01:48, 9 August 2013 (UTC)
I did a major edit of the section on organization during cell division. I hope I got the centromere/centriole thing correct (had no idea about that before I read the talk page!); feel free to correct that if I got it wrong. Also, I'm not entirely sure I got it right about polar microtubules. From the article on centromeres, it seems like there's a type of microtubule called the polar microtubule which assists in cell division, but there's also the fact that all microtubules are considered to be polar due to the end-to-end orientation of the dimers. And of course both of those definitions have nothing to do with the polarity that exists in some molecules such as water. It's very confusing! Jojojlj ( talk) 07:13, 21 October 2013 (UTC)
This section seems a little out of place and not in keeping with the rest of the article. It's a list of biophysical facts directly taken from one or two papers with no context in particular to any biological application. I appreciate that other researchers might be looking at microtubules as structures for the development of new computing architectures or explanations for the information processing capacity of the human brain. Yet these viewpoints are held by a minority and I don't believe that an encyclopaedia article should be carrying information on current research that is a minority viewpoint.
Its well known to researchers in the field that the electrostatic properties of tubulin/microtubules are considered to underlie their interactions with various proteins such as MAPs and motors.
Perhaps a section of the physiochemical properties of microtubules/tubulin would better idea?
There is an image with the legend as follows: "This image shows two components of the cytoskeleton, microtubules (green) and actin filaments (red), in an endothelial cell derived from a cow lung. The cystoskeleton provides the cell with an inner framework and enables it to move and change shape."
In my opinion the legend is incorrect. The green structures on this image look like actin fibers, and the red structures look like mitochondria.
-- Eszcze ( talk) 13:24, 1 March 2015 (UTC)
Okay, I started a request for deletion here. SPLETTE :] How's my driving? 13:05, 18 June 2015 (UTC)
Unless so few people know about it. Socialistguy ( talk) 17:33, 25 February 2016 (UTC)
The comment(s) below were originally left at Talk:Microtubule/Comments, and are posted here for posterity. Following several discussions in past years, these subpages are now deprecated. The comments may be irrelevant or outdated; if so, please feel free to remove this section.
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I would just like to comment that all of the "citations" for the microtubule entry are garbage. They all cite papers from a very narrow faction of microtubule weirdos (outside of mainstream research), and none is actually a citation of the primary research that originally demonstrated experimentally the particular fact being cited.
It appears as if someone from the tribe of "microtubule quantum consciousness" wanted to fool lay readers into believing (1) that they have contributed to the field by discovering some very important basic biological aspects of microtubules (false, these were discovered by others) and (2) their published speculation about quantum consciousness, etc is somehow true and/or commonly accepted. Just as an example, the entry correctly states that "the tubulin dimers polymerize end to end in protofilaments," but it cites a 2008 article by Vahid Rezania and Jack A. Tuszynski ("A first principle (3+1) dimensional model for microtubule polymerization"), which is a mathematical modeling of microtubule dynamics paper, not a series of biological experiments. The paper doesn't prove anything at all, let alone that "tubulin dimers polymerize end to end in protofilaments" I don't have to continue. The citations are all equally vacuous. I hate to believe that peer-review and scholarship in the field are so poor that pseudoscientists can even make a living hallucinating about microtubules, but it might be so... |
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The article begins with this sentence:
We can assume that whoever came to read this articles wants to know what microtubules are.
So including the etymology of the word in the first sentence is overloading the sentence with too much extraneous information too soon. (Sure, the etymology is a good thing to include, but not before the reader knows what the word means.)
Next we get to the word "component" which most high school students know, but younger children may not. Why use an unnecessarily advanced word when a word like "portion" or "part" will work?
Then we get to the two worst aspects of this sentence by far: two words — "cytoskeleton" and "cytoplasm" — that are highly unlikely to be in any reader's vocabulary. (Unless of course they are in the small fraction of readers who happen to know the word.)
Such words are entirely inappropriate for an introductory part of an article, and especially the first sentence, above all when simpler words can be used. That is surely true. Do not make the reader click on links in order to know what you are talking about, especially in the very first sentence. There are five links in this first sentence!
I hope the first sentence and paragraph are rewritten by someone knowledgeable about the subject, so that most 9-year-old children can understand it. I see no reason why that could not be the case. 108.245.209.39 ( talk) 21:14, 14 June 2018 (UTC)
Am I blind, or the information that the diameter of microtubules is 24 nm is not stated in the cited article? https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3232192 — Preceding unsigned comment added by Vašek Bočan ( talk • contribs) 10:01, 22 March 2019 (UTC)