The stated goal of the SENS Challenge was to demonstrate that "SENS is so wrong that it is unworthy of learned debate." Whether or not this was accomplished by a given submission was to be determined by a panel of judges, and the final judges were self-selected from a large pool of people offered positions on the panel. Persons with relevant expertise were not included in the final panel of judges, leaving only those who know little or nothing of the existing learned debate within gerontology and life extension research. We have long objected to these and other aspects related to the judging of this challenge, and they have given us little confidence in its overall structure.
Therefore, we decided to direct all of our communications -- including this response to the decision of the SENS challenge judges -- primarily to the Technology Review readership. Since we don't regard SENS to be legitimate science or engineering, we didn't criticize it as a bad or immature example of either. We also didn't attempt to show that SENS is demonstrably wrong, since this is extremely difficult to do with an untested plan comprising legitimate science bundled together with hand-waving speculations -- even though the majority of these speculations cannot be taken seriously. Instead, we used this as an opportunity to describe general features of life extension pseudoscience and we used these general features to assess SENS. We showed that SENS is stereotypical pseudoscience, with its characteristic pervasive misrepresentations, diversionary sophistry, naïve and faulty science, and so on.
The summary of the judges' opinion states that SENS is not "demonstrably wrong," and Craig Venter says we have "not demonstrated that SENS is unworthy of discussion." It seems they suggest that SENS is highly speculative theorizing but not outside the bounds of legitimate science or engineering speculation. We strongly disagree with this assessment. Here are three primary attributes of SENS that differentiate it from the kind of nascent science or engineering described by the judges:
1. Direct contradiction of key claims by much available and generally accepted evidence.
2. Aubrey de Grey's pervasive falsehoods and misrepresentations.
3. Aubrey de Grey's demonstrated misunderstanding of relevant science and engineering.
These attributes might not make SENS "unworthy of discussion" by willfully uninformed immortalist dreamers, but they certainly make SENS "unworthy of learned debate" by people interested in real gerontological science and engineering. The judges also write: "Some scientists react very negatively toward those who seek to claim the mantle of scientific authority for ideas that have not yet been proved. Estep et al. seem to have this philosophy." We think a more appropriate statement of our philosophy is that we react very negatively toward those who seek to claim the mantle of scientific authority for ideas that are directly contradicted by a vast majority of current evidence, and are based fundamentally on misrepresentations of relevant science and engineering.
Curiously, the judges deemed our submission to be the best among three, but they disagree with our overall assessment that SENS is pseudoscience without even acknowledging the reasons why we reached our conclusion. They make no comment on any of our primary criticisms or on the presentation of evidence clearly demonstrating that SENS possesses the attributes listed above, attributes that strongly suggest that SENS is unworthy of learned debate. Why not? Is their silence an implicit acceptance of such attributes in early-stage science and engineering? If so, we strongly disagree. We think the presented evidence is clear and the judges have simply failed to further investigate the pattern of Aubrey de Grey's misconduct, even though we presented to them ample justification to do so. Therefore, we provide even more evidence that Aubrey de Grey has made overtly and transparently false claims in his response to us, and despite the ease with which these falsities are found, the judges failed to detect or consider them.
Comments
07/11/2006
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Key data can be found here, particularly in the two right-most columns on “Twins distance” http://www.pnas.org/cgi/data/0500398102/DC1/5
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http://biomed.gerontologyjournals.org/cgi/content/full/56/2/B52
so readers can decide for themselves. Estep was indeed saying that variances don't matter, by saying that if the means are accelerating but the variances make the P values rise then the trend is an acceleration, i.e. the role of the variances in determining the trend of the P values should be ignored. This is exactly the mistake that Miller et al. pointed out.
Let's also not forget that Estep also described by discussion of Fraga et al. as "false and misleading" and has yet to respond to my rebuttal of that allegation.
07/11/2006
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07/13/2006
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As a layman, AdG's ideas sound similar to Ray Kurzweil's concept of "the singularity," which seems to indicate that technology will solve every problem, humans will live forever, re-engineer themselves to become anything they want to be, etc. Sounds great, but to me, those ideas are absurd on their face. Non-scientist contributors to Kurzweil's site sound (at least to me) like new-agers with a scientific vocabulary. I think this debate would look very similar if opened up to comments from the general public.
Completely apart from the scientific and funding discussion is a more fundamental question: "what would you do with all that longevity?" and "What's the matter with dying anyway?"
07/11/2006
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What would you do with all that longevity? Use your imagination.
What's the matter with dying anyway? Dying may not be too bad; it’s that long slow decay that precedes it that bothers me.
07/11/2006
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07/12/2006
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between mine and the proverbial "I saw granny and Jesus" is that my lungs
were being vacuumed at the time. The oxygen was ripped from my lungs too
fast for the brain to ponder what was happening so it then could not trick
me into experiencing a tunnel and lights. But I have experienced those before.
07/12/2006
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loop of the maneuver. I saw the tunnel and hallucinated. In this case the O2
was slowly diminishing in my brain. See the difference now using logic
instead of emotional claptrap? I remember nothing from the heart stoppage
event except lost time, nothing except being told I had to be coded. I was
dead by any measure. If, for instance, they had not revived me, does anyone
truly think I would have suddenly somehow become aware again and then
experienced entering the after life? By what criteria could that occur?
07/12/2006
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07/12/2006
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Eat healthy high nutrition food
Moderate Excerse
Never over eat
And keep mentally active
But that requires self-control and makes nobody any money. It is much easier to sell people the dream of a quick fix while they press the channel up button on their remote controls.
07/12/2006
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Regenerative medicine is hardly science fiction. Tissue engineering, stem cells, gene therapies, etc etc.. all were science fiction less than a decade ago and are now bursting wiht promise and potential. The only thing that will prevent these technologies from making a significant difference in relieving the suffering of aging in the near-term is the foot-dragging of pessimists.
07/12/2006
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Well, to start with, the Universe seems like a really big place. I'd like to know if their is life anywhere else in it, and what that life is like.
08/14/2006
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07/12/2006
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The example of the car being modified to travel to the moon is trivial next to what AdG is proposing.
Biological systems "seem" simple because the details are transparent to the user. My computer is simple because I only need to push one button to turn it on. They talk about Moore's law doubling capacity every few years, they should just add another button that will double capacity when I press it, so I don't have to replace my hardware. Should be easy, just add another button.
07/16/2006
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07/16/2006
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Your approach is the "add another button" approach vs the approach of the engineers at Intel of understanding the fundamentals and then designing and building something with the desired functionality.
Living cells are enormously more complicated than any microprocessor. Could you double the capacity of a microprocessor by retrofitting it, while remaining ignorant of the "details"? If you can, that isn't "engineering", it is magic.
07/17/2006
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07/17/2006
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Give me a link, and I will try and read the paper.
I read your papers on hydrophobicity and find the unpersuasive.
I think mitochondria must express those proteins for regulatory purposes while far from the nucleus, as in neurons. Whether a mitochondrion is a meter, an inch, or a mm from the nucleus, it can't those proteins fast enough.
Since the proteins of the respiration chain can be damaged, they have to be replacible, or the mitochondria must shut down the whole chain.
07/17/2006
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Nagley et al PNAS 85:2091
Zullo et al Rejuvenation Res 8:18
The main problem with the idea that some proteins in the respiratory chain must be synthesised near their site of function is that all the respiratory chain enzymes that have mt-coded subunits also have nuclear-coded subunits, which must necessarily be expressed at tolerably similar levels.
Feel free to email me for more expansive discourse on this. ag24@sens.org
07/17/2006
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For allotopic expression to be successful in nerve cells, you would need to show that synthesis of all proteins by mitochondria was completely unnecessary, over the lifetime of a mitochondrion as it moved out the axon, and then back to the cell body, over its lifetime of about a month.
Yes, the respiratory chain complexes have nuclear coded components, but perhaps the only "bits" that get "damaged", are the "bits" the mitochondria can replace. Maybe that is why all eukaryotes have the same 13 mtDNA coded proteins.
07/18/2006
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07/18/2006
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Mol Aspects Med. 2004 Feb-Apr;25(1-2):125-39.
Biochem Soc Trans. 2005 Dec;33(Pt 6):1399-403.
J Biol Chem. 2003 Sep 26;278(39):37223-30. Epub 2003 Jul 11.
Proc Natl Acad Sci U S A. 2001 Oct 9;98(21):12056-61. Epub 2001 Oct 2
This paper shows quite clearly regulation of mtDNA coded genes regulating metabolic activity in retinal cells. The time constant for inducing light resistance is about a day. Far faster than the turnover of mitochondria.
http://www.iovs.org/cgi/content/full/45/8/2489
07/18/2006
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The IOVS paper you reference does not, as far as I can see, say anything relevant to the feasibility of allotopic expression. The experiment describes the ability of eyes accustomed either to dim or to bright light to cope with very bright light. What are you inferring from this?
07/19/2006
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If nitration produces irreversible inhibition of proteins, that inhibition can only be "reversed" via protein synthsis. If mitochondria are unable to synthesize proteins, they lose the ability to recover from this regulatory mechanism.
The ongoing protein synthesis by mitochondria is (to me) pretty good evidence that ongoing protein synthesis is necessary for proper function. Allotopic expression in nerve cells requires that ongoing protein synthesis by mitochondria is completely unnecessary.
07/19/2006
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If nitration produces irreversible inhibition of proteins, that inhibition can only be "reversed" via protein synthsis. If mitochondria are unable to synthesize proteins, they lose the ability to recover from this regulatory mechanism.
The ongoing protein synthesis by mitochondria is (to me) pretty good evidence that ongoing protein synthesis is necessary for proper function. Allotopic expression in nerve cells requires that ongoing protein synthesis by mitochondria is completely unnecessary for optimum and long term mitochondrial function.
07/19/2006
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The differential expression in retina, if meaningful at all, cannot be only of the proteins discussed, because the stoichiometry of the subunits in a given enzyme complex is fixed. It may be that (to use examples from the paper) COIII is regulated by mRNA degradation rates and COII and COI by translation rates, but the overall effect must be (to an approximation that the cell can handle) equivalent. And moreover, the same must be true of the nuclear-coded subunits - whose regulatory DNA is available to us to use in the engineered transgenes. It is of course possible that the coding sequences themselves are important for regulation, but that's not a common finding in biology, so hardly a reason not to try. And on top of all that, the null hypothesis is that all will be fine unless some subunit is made in inadequate quantities: making some in excess should be harmless, as it will just be degraded by (e.g.) Lon when unused.
07/19/2006
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07/19/2006
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If AE can't work for neurons, SENS can't work for neurons either. It takes a long time (couple of weeks?) for mitochondria to be transported out an axon to the tippy end of a motor neuron.
Maybe you can redesign mitochondria to use only imported proteins in neurons, but that won't be done using the "same" proteins, and is a completely different degree of difficulty than what you are proposing. It is many orders of magnitude more difficult.
07/19/2006
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07/20/2006
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07/21/2006
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Again: I didn't invent the idea of AE. Rather a lot of top mitochondriologists were interested enough in it to work on it a decade ago, and would still be doing so if grant review study sections were less conservative. That's pretty good evidence that there's no obvious reason why it's doomed.
07/19/2006
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J Appl Physiol. 2000 May;88(5):1601-6
J Biol Chem. 1990 May 5;265(13):7532-8.
This last one, they quite clearly show protein synthesis in isolated mitochondria regulated by membrane potential and inhibited by chloramphenicol.
Since mitochondria synthesize some components of the respiration chain, and import others, mitochondria must have a way of assembling those various components.
Different components of the same respiration chain complex have different lifetimes.
J Biol Chem. 1982 Apr 10;257(7):3575-80
07/19/2006
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As for the JBC 1982 paper, be careful. The only complex with heterogeneous turnover rate was Complex III, and even there the sole mt-coded subunit (cytochrome b) had the same rate as three nuclear-coded ones. Bear in mind also that this experiment would have included subunits never assembled into complexes, so the differences seen may be some subunits being synthesised/imported in excess and promptly degraded. Such modest inefficiency of regulation is no surprise in a dysregulated cell population such as a hepatoma line in vitro.
07/20/2006
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Turning off mitochondria is "bad", but it is "better" than malignant hyperthermia.
07/17/2006
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07/18/2006
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Medicine seeks to restore "normal" functionality. You seek to operate an essentially unknown system outside its normal range, achieve superior functionality, without understanding the "details".
I am not saying that what you propose is "impossible". You are saying it can be done in 10 years with modest funding. A funding level that is on the same order as that to bring a new simple drug to market.
I think you understimate the degree of difficulty by at least 6 orders of magnitude.
07/18/2006
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Also, I'm only saying it can be done in **mice** in 10 years with modest funding.
07/18/2006
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Your "car" analogy is inappropriate. Mechanical objects do not deteriorate when stored properly, or when inactive for repair. Every component of a mechanical system can be replaced independently. The "repair system" (mechanics + tools + information + spare parts) is external to the car and is subject to unlimited modification with no effect on the car. The "details" of the car are completely understood.
07/18/2006
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When vintage cars are taken out of service, continued damage stops. Most of the damage that occurs to humans happens after the initial infarct, as in ischemia-reperfusion injury.
Many of the "damage" mechanisms in humans are actually "features" that are protective under other circumstances. Apoptosis, shock, inflammation, excitotoxic death. How will you regulate those without understanding when they are good and when they are bad?
07/18/2006
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07/19/2006
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Metabolicly active cells generate free radicals as necessary components of their metabolic activity. Many transcription factors are regulated by redox active free radicals. How do you propose to repair or obviate the "damage" done by free radicals without understanding what is "damage", and what is a "signal" for transcription factors to initiate "repair"?
07/18/2006
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07/18/2006
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Mice with a lifespan of 80 years would be a clever parlor trick, but one that would take 80 years to demonstrate.
So how do you "validate" success using mice? If you exceeded a human lifespan you would certainly be on to something, but that will take 80+ years to demonstrate. Something less than 80 years might not be as good as what humans already have.
07/18/2006
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07/19/2006
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07/18/2006
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The time constant for mtDNA protein synthesis is < 1 minute. For SENS to work in motor neurons, there must be no adverse effects from increasing that time constant by 5 orders of magnitude, from 1 minute to 1 week.
07/20/2006
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07/21/2006
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Expression of nDNA and mtDNA coded proteins is regulated differently by local ATP demand. nRNA is confined to the cell body, complex IV activity correlates with expression of mtDNA coded COX III, not nDNA coded COX Vb. THE JOURNAL OF COMPARATIVE NEUROLOGY 373: 139-155 (1996).
mt coded and nuclear coded subunits of complex IV are disproportionately regulated by local ATP demand. Complex IV activity correlates with mtDNA coded mRNA and COX I (mt coded) and not COX IV or COX VII (n coded). The Journal of Neuroscience, May 1993. 13(5): 1805-1819
07/22/2006
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Limiting the quantitiy of active complex IV in respiring mitochondira is an important control feature that equalizes O2 consumption between many mitochondria, matching O2 diffusion and consumption with ATP demand. Attempting to substitute mitochondria fully loaded with completely active complex IV would not work as a substitute.
07/22/2006
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07/23/2006
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The Journal of Neuroscience, May 1993. 13(5): 1805-1819
are both in vivo demonstrations of cytochrome oxidase activity and correlated by immunoassay with quantity of holoenzyme, correlating with mtDNA. IN VIVO!
It is only the non mtDNA coded subunits that can be in excess. Those are metal-free. It is the mt synthesized units that are the active site, and which contain Cu and heme.
07/23/2006
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07/24/2006
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07/24/2006
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The allosteric regulation of CO by ATP doesn't change the amount of CO present.
07/23/2006
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07/24/2006
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Take out that control loop, which AE does, and ATP is not as well controlled.
07/24/2006
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- chemiosmosis itself
- UCP opening/closing
- allosteric regulation
The idea that the loss of a far less flexible additional control loop (less flexible because it relies on protein synthesis) would be so clearly fatal to mitochondrial function that AE is a non-starter is, to say the least, not a logical conclusion.
Mitochondria include over 1000 proteins. Your objection to AE relies on the proposal that neuronal mitochondria can function perfectly well importing all but 13 of those proteins from the cytosol but would be fatally affected if they had to import the other 13 too. That is a priori an extremely implausible hypothesis, and non-physiological data aren't much use in strengthening it. Yet you're using that logic as a reason not to try to develop a key component of a therapy that could defeat aging and thus save 100,000 lives a day. Where's your sense of proportion?
07/24/2006
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You assert that SENS via AE provides all the functionality of mitochondria. That understanding the "details" are unimportant because AE can replace them all.
I have shown that is clearly false by presenting data where mtDNA is essential in providing a regulatory function that AE cannot possibly supply.
07/25/2006
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07/25/2006
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Your premise of SENS is that AE can replace all mitochondrial functions with no loss in functionality, so we can "sidestep" our ignorance. I demonstrate a functionality that AE cannot provide, you simply assert that functionality is unimportant because other things are more important. Huh? Unless we understand how all of the thousands of coupled non-linear systems interact, we can't really say which (if any) are so unimportant they can be discarded.
07/25/2006
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I have shown that. It is no longer an a priori situation.
You must now show that every functionality that cannot be provided by AE is unimportant and will have no adverse effect(s) on cell metabolism under any circumstance(s).
07/25/2006
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Every cell that "dies" will go through the ATP level that you consider so "non-physiological" that it can be ignored. An obviously false assumption.
07/26/2006
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07/26/2006
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I have shown a control function that requires mtDNA expression, and which cannot be accomplished via AE. (an existance proof).
You then waved your hands and said those ATP levels are unimportant. I then showed that all cells pass through those ATP levels during their lifetime.
You are the one asserting that functionality is so unimportant under each and every circumstance, that it can be ignored. Do you have some data to back up that assertion?
07/26/2006
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> unknown) of mt can be accomplished via AE, and that understanding the
> details of mt function and control are completely unnecessary.
Correct.
> I have shown a control function that requires mtDNA expression, and
> which cannot be accomplished via AE. (an existance proof).
Incorrect. None of your cited data demonstrate the need for any protein to be expressed from mtDNA.
07/26/2006
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> then showed that all cells pass through those ATP levels during their
> lifetime.
Incorrect. I said that the method of induction of those ATP levels was not physiological, and I also said that the location of the genes that control ATP level is of negligible relevance to the sensitivity of that control, and that none of the data you've cited demonstrate otherwise. I still say that.
> You are the one asserting that functionality is so unimportant under
> each and every circumstance, that it can be ignored. Do you have some
> data to back up that assertion?
Sure. Let's start with the Wong-Riley paper you cited: it showed that in each and every relevant enzyme complex some nuclear-coded proteins have the same turnover rate as the mt-coded ones.
07/26/2006
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07/26/2006
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07/27/2006
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By the way, when I said "Wong-Riley paper" earlier I actually meant the Hare and Hodges 1982 JBC paper - my apologies.
07/27/2006
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This shows expression of mt and n COX subunits in both different time and space. pCOIV is stable long term and makes hCOX when mtDNA is expressed. For AE to work, pCOs from mt would need to be stable for weeks instead of minutes, and "triggerable" in response to local ATP demand.
07/27/2006
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07/27/2006
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07/28/2006
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The leader sequence is much much shorter than pCOI. There are only 2 mechanisms for import of mt proteins, electrophoresis and chaperone mediated folding in the matrix. Proteins that span the outer and inner membrane require the proper sequence along the whole length, not just the leader. mt coded proteins had no need to evolve the proper sequence for import. There is no reason to suppose that they posess it.
07/30/2006
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07/31/2006
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08/01/2006
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08/02/2006
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Initiation isn't enough, the whole protein has to be imported.
If proteins are stored in the intermembrane space, what triggers import to matrix?
08/03/2006
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08/03/2006
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The number of AA in mt coded CO subunits is about 2x than it N coded. The intermembrane space would get crowded with 3x the volume stored there via AE.
If there is no COX without COI-III, then the newly synthesized CO's go into the matrix and are degraded.
When hCOX gets "tired", it comes out of the membrane into the matrix and gets degraded, making room in the membrane for more hCOX. You could store several times more enzyme this way, which translates into several times longer mt lifetime.
08/03/2006
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08/04/2006
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If AE *can't* work for for just one of those tissue compartments, SENS *can't* work either.
The problems of AE may well be greater for complex I. I suspect it is. Complex I is trickier to work with than CO, which is I think why there isn't as much data on it. ND6 is coded separately from the other mt proteins. It is probably "special".
08/04/2006
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08/05/2006
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08/08/2006
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08/08/2006
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If we are going to "sides step our ignorance", how do we "side step" the proteins not acting the way we need them to for our "side stepping" to work?
Assume because we can get 99.9% of the proteins in there, that the 1 we can't doesn't matter? Even if it is pCOXI?
08/01/2006
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08/02/2006
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The point of the Wong-Riley result is that pCOIV is sequestered, and hCOX is created de novo by local expression of mtDNA.
If you can't sequester pCOI-III, you can't form hCOX de novo, and if you do, the sequestered pCOI-III takes up 2x the volume of the pCOIV-VII so your mt lifetime is 1/3 as long.
Either way, SENS via AE will not work.
08/03/2006
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- you missed three n-coded subunits of sizes 147, 109 and 84 -- see here:
http://www-bioc.rice.edu/~graham/CcO_sequences.html
- they all have leader sequences, which if the Wong-Riley result is typical
are not cleaved
- you also have to count all the accessory subunits involved in assembly
So even if we restrict ourselves to CO, the actual ratio is closer to 1:2 than 2:1. And of course your model *can't* be restricted to CO, because you have no evidence that CO holoenzyme has a shorter halflife than any other complex.
08/04/2006
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CO probably has the longest half life of any complex under most circumstances. Production of superoxide is a control feature so will change as local conditions change.
How do you propose to regulate the cleaving of the leader(s) and assembly of hCO? It looks like the trigger now is insertion of COI-III into the inner membrane, formation pre-hCO, change conformation such that leader(s) cleaved form hCO.
08/04/2006
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http://www.life.uiuc.edu/crofts/bioph354/cyt_ox.html
Moreover, if CO is relatively long-lived as you suggest, then either the other complexes regulate their n-coded subunits some other way (such as axonal transport independent of mitochondria), or else they dominate the precursor storage problem and it's their nuclear-to-mt ratio that you should be considering.
If you have any evidence that cleavage of pCOIV leader happens after insertion of COI-III into the membrane, let's hear it.
08/05/2006
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Maybe it is only the mt coded part of the complex that has a short half life. Maybe the n coded stuff lasts a long time. The metal centers tend to be on the mt coded stuff. They are likely more subject to damage.
Cleavage happens after transport of mt out axon, and before formation of hCO. Obviously some change in the mt trigger it. Many different stimuli are known to trigger expression of mtDNA, which is known to precede formation of hCO. Proteases are not coded by mt, so what causes the cleavage of pCOIV leader is a structural/conformational/location change. Formation of hCO from subunits is a big conformation change. Why assume another one is necessary?
08/08/2006
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08/08/2006
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Now, your new suggestion is altogether more interesting -- that the synthesis of the mt-coded subunits could be the trigger for maturation and assembly of the n-coded ones. For the first time in this immense thread I see no reason why you are necessarily wrong. However, as you say, many stimuli are known to trigger mtDNA transcription and translation... and thus these stimuli too are available to trigger pCOIV maturation and assembly. Thus, I don't need to propose a new trigger for maturation - there are ample already. I do need to propose a new system for *delay* of maturation until this trigger occurs, but so do you.
08/08/2006
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08/13/2006
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2) In vivo, OXPHOS-negative cells hardly ever have no mtDNA; rather, they have large deletions. Thus, there still is mtDNA to be transcribed.
08/14/2006
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If mt degrade all these proteins, there are enzymes to do so, and also mechanisms to distinguish which proteins to proteolyse and which ones not to. It isn't like the proteosome, where proteins get tagged, the specificity has to do with something else.
It can't be just the leader, because there are lots of soluble proteins in the matrix.
08/01/2006
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08/02/2006
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Forms that depend on the specific sequence and how those specific sequences interact with all the Hsps, other chaperones all the proteases, and all the other proteins so they don't agglomerate.
Why would pCOI just "happen" to act precisely the same way? There is no reason to suppose that it would. It is more likely that unincorporated COI is a danger signal and is rapidly degraded.
08/01/2006
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08/02/2006
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Patients with mitopathies have functional mitochondria that don't work well. Augmenting their function via AE is completely different than SENS.
You are pretending that SENS via AE is "engineering". It isn't.
"Proportional" doesn't work for high n systems that are coupled and non-linear, which all biological systems are. Such systems are chaotic.
07/25/2006
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07/25/2006
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AE is not SENS. SENS is replacement of all 13 mtDNA coded proteins via AE while remaining ignorant of the details.
SENS is going to the moon. AE is gaining some altitude. I can gain some altitude by jumping, I can't get to the moon that way.
07/25/2006
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07/25/2006
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I know there is no data to support your assertion because there are no techniques for measuring the local ATP level on the length scale of mt spacing and correlating it with gene expression.
We know that cells die, we know that when they do, their ATP level goes to near zero. Obviously passing through the level that you consider unimportant.
07/26/2006
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07/26/2006
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07/25/2006
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07/23/2006
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07/24/2006
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07/23/2006
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One more time: you have provided zero evidence that mitochondria in neurons in vivo actually turn over their mt-coded proteins faster than every few weeks. Unless and until you can show that they do, your argument that AE is hopeless totally collapses. Please stop citing papers that do not bear on the question on which your conclusion unambiguously depends.
07/24/2006
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The Journal of Neuroscience, May 1993. 13(5): 1805-1819 Quoting from their abstract: "acute regulatory changes in CO activity occurring over periods of days are controlled mainly by regulation of the mitochondrial genes that encode the catalytic subunits of the enzyme."
07/24/2006
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07/24/2006
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"Maybe" the mtDNA proteins now coded as precursors, designed to be stable (in quite a difficult environment), soluble and triggerable "just in time" can stored, but if the volume of a mitochondria's "lifetime" supply, exceeds the volume of mtDNA and ribosomes, you will never get the same energy density or functionality.
07/22/2006
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If you can't even guess how difficult it is, it isn't "engineering". For it to be "engineering", you need to have a defined path.
07/22/2006
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07/23/2006
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07/27/2006
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07/27/2006
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If the Wright brothers' designs had not worked, it would only have falsified their hypotheses for those specific designs. The hypothesis that heavier than air flight was possible could not be falsified because it was already known to be true because birds did it.
07/27/2006
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07/27/2006
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07/31/2006
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07/31/2006
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I have no doubt that longer lived mt exist, and no doubt that in principle longer lived mt can be created that are human compatable.
None of those long lived organisms use AE. They all code every single one of those 13 mt coded proteins in their mt. Bristle cone pines code a lot more besides. So I don't think your analogy is apt.
08/04/2006
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Another "partial falsification" would be if a type of age-related change other than those that SENS enumerates (eg, aspartate racemisation of long-lived proteins) were shown to contribute to aging. Then a way to combat that (e.g. stimulating turnover) would also be needed as an additional SENS component.
07/27/2006
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Unless all possible combinations are tried, a hypothesis is not falsified by the absence of a success.
Are you saying SENS can only be falsified by trying all possible combinations of all possible proteins with all possible sequences?
07/27/2006
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07/27/2006
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"ITER is a joint international research and development project that aims to demonstrate the scientific and technical feasibility of fusion power." http://www.iter.org/
We know that thermonuclear fusion happens. There have been multiple devices that have produces energy from fusion, just not "efficiently enough", or "economically enough". If SENS is to be compared to fusion projects, it should be compared to those of the 1950s. When they thought it was trivial and would bring power "too cheap to meter" in just a few years.
Trying to build ITER in 1950 would have been a waste of money. Trying to build the Big Dig in 1850 would have been a waste of money too.
07/27/2006
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Going to the moon for a week for $100 is trivially falsified because a week's labor at minimum wage is more than that.
Research on SENS may be justified, but it is research, not engineering. You can't "sidestep" ignorance in engineering. Either your design accomodates ignorance successfully or your design fails.
Trial and error shots in the dark is the Edisonian approach to research, he sized distribution wire by experiment. Sprague engineered the size of wires by calculation.
07/27/2006
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You have made a number of assumptions (aka guesses), regarding the degree of difficulty of AE. Those assumptions are difficult to evaluate because AE hasn't been done before.
At the end of 10 years and $1 billion will SENS be either successful or falsified? Or will we know that $1 billion worth of "magic" bullets don't work, but $1 billion of something else might?
07/27/2006
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Bottom line: your argument against pursuing SENS now is a guess, and a considerably less educated guess than my contrary one, because I've been studying the component technologies, publishing on them, and discussing them with the leaders in the relevant fields for several years.
07/28/2006
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No amount of “expertise” would allow an engineer to simply walk the Big Dig site and “estimate” project cost without doing soil borings. Pretending you can, is not “engineering”, it is gambling. Those who "budgeted" the Big Dig knew how to get accurate budgets, they chose not to. You don't know how to get an accurate budget for SENS.
My argument against persuing SENS now is that there are plenty of other projects that will save more lives in the nearer term than SENS will.
07/30/2006
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> Those who "budgeted" the Big Dig knew how to get accurate budgets, they
> chose not to. You don't know how to get an accurate budget for SENS.
Quite true - but as I already said, you an call SENS and fusion R&D rather than engineering and the argument for pursuing them still applies, because they're goal-directed.
> My argument against persuing SENS now is that there are plenty of other
> projects that will save more lives in the nearer term than SENS will.
What's so important about the nearer term? If we thought the way you suggest, we'd never have started work on fusion, because the money could always have been spent making energy a bit cheaper in easier ways.
07/31/2006
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However, it is of infinite value to those people that are alive today only if it can be attained during their lifetime. The SENS gamble makes sense in that context.
It is not clear if immortality is of infinite value to society. Many people are already dying of starvation and diseases that can be prevented. SENS will not change that, it may even make it worse. We do not currently posess the technology or political will to provide every human with an acceptable lifestyle in a sustainable manner.
When global warming melts Greenland it will raise sea level by 7 meters. Many hundreds of millions will be displaced. I consider that a more important problem than SENS.
07/30/2006
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07/31/2006
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07/31/2006
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> only if it can be attained during their lifetime.
Wrong, because people have value to each other. I, for example, feel that I'll die happy if I've helped bring the defeat of aging closer.
07/31/2006
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> prevented. SENS will not change that, it may even make it worse.
No - defeating aging could well empower humanity and give us the determination to prevent preventable things. Preventable things persist now mainly because of ubiquitous fatalism, which I think results mainly from the inevitability of aging.
07/31/2006
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> meters. Many hundreds of millions will be displaced. I consider that
> a more important problem than SENS.
That's the first time I've heard displacement rated as more serious than death... But also, it's highly implausible that combating global warming and combating aging will impinge on each other's budgets.
07/31/2006
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07/31/2006
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http://www.imminst.org/forum/index.php?s=&act=SF&f=173
prometheus
08/19/2006
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2. Increase the rate of turnover (autophagy) in faulty (ROS leaky or poor ATP producers)
prometheus
08/19/2006
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