Understanding through Discussion


Welcome! You are not logged in. [ Login ]
EvC Forum active members: 81 (9005 total)
69 online now:
AZPaul3 (1 member, 68 visitors)
Newest Member: kanthesh
Post Volume: Total: 881,158 Year: 12,906/23,288 Month: 631/1,527 Week: 70/240 Day: 33/4 Hour: 0/0

Announcements: Topic abandonment warning (read and/or suffer the consequences)


Thread  Details

Email This Thread
Newer Topic | Older Topic
  
Author Topic:   The great basic question of science on origin of life
Blue Jay
Member (Idle past 1326 days)
Posts: 2843
From: You couldn't pronounce it with your mouthparts
Joined: 02-04-2008


(2)
Message 18 of 64 (776499)
01-14-2016 12:25 PM
Reply to: Message 17 by Vladimir Matveev
01-14-2016 11:05 AM


Hi, Vladimir.

Welcome to EvC!

Vladimir Matveev writes:

Since the sodium-potassium pump (Na+/K+-ATPase) was discovered, no molecular model has been proposed for a predecessor of the modern sodium pump. Neither Miller's electrical charges, nor Fox's amino-acid condensation, nor building ready-made biomolecules into coacervates; none of this has managed to lead to the self-origination of the progenitor of the ion pump even in favourable lab conditions.

Let's see if I understand you correctly here. Basically, the sodium pump is irreducibly complex. There are no known progenitor molecules, and all experiments attempting to spontaneously form sodium pumps or insert them artificially into membranes have failed. This is therefore evidence that sodium pumps cannot have emerged spontaneously in nature.

Is this a fair restatement of your claim?

Vladimir Matveev writes:

It is impossible to explain the properties of well-studied cellular model (Fox's microspheres) on the basis of fudamental ideas of membrane physiology (lipid membrane, ion channels, sodium pump).

I also don't know what you're saying here. Are you basically saying that protocells couldn't have functioned without both membranes and sodium pumps, so the membrane-and-pump system is irreducibly complex?

Vladimir Matveev writes:

3) According to recent studies, non-membrane phase compartments play an important role in the functioning of the cell nucleus, nuclear envelope and then of cytoplasm. Somebody sees the compartments even as temporary organelles. According to available data, the phase compartments can play a key role in cell signaling.
(4) In the view of non-membrane phase approach, the usage of liposomes and other membrane (non-biophase) cell models to solve the issue of the origin of life is a deadlock way of the investigation.

So, phase compartments are basically bubbles of liquids that are separated from one another, but aren't divided by membranes, kind of like a drop of oil floating in water?

Here, you seem to be saying that phase compartments could have played a role in structuring proto-life processes, but do not help explain the origin if the sodium pump, because a sodium pump needs a membrane to be useful.

-----

Have I represented you fairly in my restatements? If not, can you please explain where I have misunderstood you?


-Blue Jay, Ph.D.*

*Yeah, it's real

Darwin loves you.


This message is a reply to:
 Message 17 by Vladimir Matveev, posted 01-14-2016 11:05 AM Vladimir Matveev has responded

Replies to this message:
 Message 19 by Vladimir Matveev, posted 01-14-2016 10:49 PM Blue Jay has responded

  
Blue Jay
Member (Idle past 1326 days)
Posts: 2843
From: You couldn't pronounce it with your mouthparts
Joined: 02-04-2008


Message 27 of 64 (776540)
01-15-2016 11:30 AM
Reply to: Message 19 by Vladimir Matveev
01-14-2016 10:49 PM


Hi, Vladimir.

Vladimir Matveev writes:

No experimental evidence of spontaneous emergence of the sodium pump in the literature. The scientific method requires experimental evidence.

Good. At least I got one of your points right.

My rebuttal is that a lack of evidence doesn't mean it didn't, or couldn't, happen. I think a lot more work needs to be done before we can reasonably draw that conclusion.

Vladimir writes:

This statement relates to the ability of the microspheres to generate an action potential which is indistinguishable from action potential genereted by living nerve cell. The well-known mechanism of action potential of a living cell can not be applied to the microspheres (the microspheres have NO a lipid membrane, specific ion channels and sodium pump).

Okay, apparently I was wrong about what a "microsphere" is. I thought it was just another name for a protocell with a lipid bilayer membrane. I found the Wikipedia page for Sidney W. Fox, which clarifies that his concept of a "protocell" was a spherical arrangement of protein-like molecules.

Thanks for clarifying that for me. I don't understand how Fox's microspheres fit into the Origin-of-Life process, so I will assume that you're right. Let's ignore "proteinoid microspheres" in this discussion.

But, if I extrapolate a bit, I think you are essentially arguing that a protocell requires a mechanism for generating an action potential relative to its surroundings. Do you think the protocell could not have survived without this mechanism?

RAZD proposed that a protocell might simply tolerate changes in turgor and ion gradients, until it evolved a mechanism to regulate ion flux. Do you think this tolerant "spore" state is impossible?

-----

Vladimir Matveev writes:

The phase state of matter has special properties and it does not need in the membrane as a prison needs in a fence. The phase properties are determined by adsorption processes. Selective adsorption-desorption and ion exchange properties create inside physical conditions necessary for life processes. With this understanding fully functional membrane is not necessary. Why should we give up such a mechanism of origin of life?

Okay, I understand that the boundary between different phase compartments can act somewhat like a membrane.

I don't understand your last question, though. Do you think phase compartments eliminate the need for membranes? I don't agree. I imagine that the chemistry of phase compartments would be much more delicate than membrane-bound bodies, and would thus require a lot more complex molecular mechanisms to maintain them. Is my assumption wrong?


-Blue Jay, Ph.D.*

*Yeah, it's real

Darwin loves you.


This message is a reply to:
 Message 19 by Vladimir Matveev, posted 01-14-2016 10:49 PM Vladimir Matveev has responded

Replies to this message:
 Message 29 by Vladimir Matveev, posted 01-15-2016 12:19 PM Blue Jay has responded

  
Blue Jay
Member (Idle past 1326 days)
Posts: 2843
From: You couldn't pronounce it with your mouthparts
Joined: 02-04-2008


Message 28 of 64 (776541)
01-15-2016 11:58 AM
Reply to: Message 26 by Pressie
01-15-2016 8:19 AM


Hi, Pressie.

Pressie writes:

So, I take it that your paper was deemed as being pretty horrendous amongst your peers and now you are trying to cry on non-peer shoulders?

Actually, no. He linked to a FirstView article, which means it's been peer-reviewed and accepted for publication, and it will appear in an upcoming issue of the journal. It's a small, young journal, but it seems legitimate; and Vladimir himself seems to have a legitimate scientific pedigree.

I haven't read the paper yet (paywall), but based on the abstract, it seems that he is simply arguing that most hypothetical models of "protocells" are too dissimilar from living cells to be plausible. He seems to be doing a lot of cut-n-paste from a "highlights" document he posted on his personal website (here). I wonder if the actual manuscript will include his little reference to "Providence"?

So far in this thread, it seems like he is a supporter of Intelligent Design, which means I ultimately think he's wrong in some way. But, since he's an actual researcher in the field, and he seems to know more about cell physiology than I do, I think it would be worthwhile to try to engage him constructively. I've already learned a couple new things.

Edited by Blue Jay, : No reason given.


-Blue Jay, Ph.D.*

*Yeah, it's real

Darwin loves you.


This message is a reply to:
 Message 26 by Pressie, posted 01-15-2016 8:19 AM Pressie has not yet responded

  
Blue Jay
Member (Idle past 1326 days)
Posts: 2843
From: You couldn't pronounce it with your mouthparts
Joined: 02-04-2008


Message 30 of 64 (776546)
01-15-2016 1:19 PM
Reply to: Message 29 by Vladimir Matveev
01-15-2016 12:19 PM


Hi, Vladimir.

Vladimir writes:

I believe that an abiotic synthesis of proteins, and properties of proteins are studied well enough. If the spontaneous formation of the pump would be possible in principle, it has already happened.

This is a very bold claim, Vladimir. There is just too much we don't know.

Consider the scale. How many experiments have attempted to spontaneously produce proteins under hypothetical prebiotic conditions? Hundreds, maybe? Well, how many "experiments" might have been conducted by Mother Nature on the prebiotic Earth before She succeeded in producing a viable protein? Possibly trillions. It's like rolling the dice 10 times and concluding that '3' is impossible because we haven't seen one yet.

Consider the other options. The pump doesn't necessarily have to suddenly emerge, fully intact: it may begin as a simple protein that bonds to an ion, or a simple protein that intercalates into a membrane, and gradually gains the other functions of a sodium pump via later innovations. This is why RAZD and I proposed protocells that could survive without a sodium pump: because if they could survive without it, then it could have evolved gradually later, and wouldn't have to appear suddenly, spontaneously, fully intact.

These are very real possibilities that you are just dismissing because we believe "proteins are understood well enough." That seems very narrow-minded to me.

Vladimir Matveev writes:

Why the microspheres are able to generate an action potential without fully functional membrane, that is the question.

The microspheres can generate an action potential without a membrane?

Vladimir Matveev writes:

Blue Jay writes:

RAZD proposed that a protocell might simply tolerate changes in turgor and ion gradients, until it evolved a mechanism to regulate ion flux. Do you think this tolerant "spore" state is impossible?

Ion gradients are impossible without pumps

That's not strictly true. Ion concentrations can change in the environment for various reasons, and those changes inevitably create temporary ion gradients. Imagine a protocell (lacking an ion pump) in a pond where the salinity changes. That protocell would need one of two things:

  1. A mechanism to preserve its internal chemistry against changes in the salinity of the outside environment
  2. An ability to simply tolerate the change in its internal chemistry as the environment changes.

Is there any evidence that a protocell without an ion pump would perish?

If not, it seems that there is still a perfectly valid and reasonable hypothesis for the evolution of ion pumps in protocells that originally lacked them.

Vladimir Matveev writes:

The ability of proteins to spontaneous synthesis is proved by experiments. But with the pumps we have a problem: we are waiting for their second coming.

This just seems like a restatement of the "tornado in a junkyard making an airplane" argument. I think you're being too quick to dismiss the possibilities based on far too little evidence.

Vladimir Matveev writes:

I go to sleep.

Have a good night! It's lunchtime for me!


-Blue Jay, Ph.D.*

*Yeah, it's real

Darwin loves you.


This message is a reply to:
 Message 29 by Vladimir Matveev, posted 01-15-2016 12:19 PM Vladimir Matveev has not yet responded

  
Blue Jay
Member (Idle past 1326 days)
Posts: 2843
From: You couldn't pronounce it with your mouthparts
Joined: 02-04-2008


Message 48 of 64 (776802)
01-20-2016 11:43 AM


To Vladimir
Hi, Vladimir

I apparently misunderstood you from the beginning. Many times when you wrote something, I interpreted it as saying the opposite. Others seem to have had much more success understanding you than I have, so I will leave it to them.

My apologies for the misapprehensions.


-Blue Jay, Ph.D.*

*Yeah, it's real

Darwin loves you.


Replies to this message:
 Message 49 by Vladimir Matveev, posted 08-07-2016 12:29 AM Blue Jay has not yet responded

  
Newer Topic | Older Topic
Jump to:


Copyright 2001-2018 by EvC Forum, All Rights Reserved

™ Version 4.0 Beta
Innovative software from Qwixotic © 2020