Protocell redux

[DNAunion]

Communication?

It is also claimed that proteinoid microspheres communicate by exchanging information-containing molecules.

“Inasmuch as the endoparticles [that move from the interior of one microsphere into another through a connecting, hollow proteinoid junction] are composed of proteinoid, and the proteinoid has been shown to be informational (page 174), the phenomenon constitutes a model for the origin of communication. This model relates to either intercellular communication or intergenerational communication; in fact, the phenomenon suggests the simultaneous origin of both types of communication (Hsu et al., 1971).” (Molecular Evolution and the Origin of Life, Sidney W. Fox and Klaus Dose, W. H. Freeman and Co., 1972, p217)

Although this claim of microsphere “communication” may be technically true, it easily could be considered an exaggerated use of the term (a charge levied against Fox on many of his other proteinoid claims).

First of all, Fox’s statement “… and the proteinoid has been shown to be informational (page 174)…” is troublesome. The term “information” does not even appear on page 174. The most pertinent statement on that page is “The proteinoids are seen to have the properties of enzymes, hormones, and food”. Is this the support Fox alludes to in his troublesome statement? If he is trying to establish proteinoids as information-bearing molecules because they “have the properties of enzymes”, then he is supporting one exaggerated claim with another. Proteinoids have very weak and limited catalytic abilities. Saying that they “posses the properties of enzymes” is disingenuous.

Second, of the numerous pertinent definitions of the term “information”, Fox chooses the broadest.

“Information is defined here as the capacity for selective interaction of one molecule or system with another. Information is not restricted to living systems in this discussion.” (Molecular Evolution and the Origin of Life, Sidney W. Fox and Klaus Dose, W. H. Freeman and Co., 1972, p239)

Note that this is a perfectly legitimate definition. Still, it is about as inclusive a definition as one can use.

Third, and most importantly, the transfer of the information-bearing molecules is not controlled by any biological mechanisms: it is driven, as are almost all of microspheres’ “cell-like” processes, by simple physical forces. In concentrated pools of proteinoid microspheres, some of the “protocells” make contact and a hollow, tube-like junction made from proteinoid forms between them. Since proteinoid particles may be contained within microspheres, random molecular movements (Brownian motion) can cause some of these endomicroparticles to eventually “find” and pass through the connecting junction into the neighboring microsphere.

“Figure 6-19 presents the evidence that very small proteinoid microparticles can pass through the junctions, and that the connections must therefore be hollow. … The transfer of endoparticles results from Brownian motion within the microsphere, which continues until the endoparticle happens to reach a junction.” (Molecular Evolution and the Origin of Life, Sidney W. Fox and Klaus Dose, W. H. Freeman and Co., 1972, p215)

This is haphazard “communication” driven purely by chance. Furthermore, the transferred particle gains no new function in the second microsphere, nor does it trigger any chemical reactions upon its arrival. This process is merely the simple, random movement of a minute solid suspended in a liquid. If a dead leaf falls into a lake at the east bank, and is eventually transported to the west bank by the random motions of waves, have the two banks really communicated?

 

[DNAunion]

Fox’s Exaggerated Claims

In addition to the already-mentioned exaggerated claims of his proteinoid microspheres (they bud like yeasts, reproduce, communicate, etc.), Sidney Fox made others.

“Fox’s experiment was an intriguing one, but unfortunately he stepped beyond the boundaries of his experimental data. He claimed that as his amino acids were heated and joined together, they tended to order themselves into reproducible sequences rather than simply linking up at random [he claim was found to be untrue]. He characterized this process as the very beginnings of life, constituting a “biomacromolecular big bang”. (Christopher Wills & Jeffrey Bada, The Spark of Life: Darwin and the Primeval Soup, Perseus Publishing, 2000, p53)

“Subsequently, Fox made a career out of investigating the properties of his proteinoid microspheres. He eventually advanced and championed the claim that these were indeed primitive cells. According to Fox, the microspheres had a wide range of catalytic activities, were made up of double layers of the kind that surround living cells, and underwent budding or fission in a manner that looked like reproduction. …

Fox was an excellent self-promoter. His claims that proteinoid microspheres were lifelike eventually appeared in several biology textbooks, something that he constantly mentioned in his talks and papers. …

Fox’s work turned out to be too good to be true. Soon holes began to appear in his claims. In particular, a number of scientists examined his assertion that amino acids tended to join together nonrandomly when they were dried, and found that it was not correct. Proteinoids really were the result of essentially random linkages among amino acids. And it was difficult to see how such distorted, nonlinear, and indeed nonbiological molecules could have played much of a role in the origin of life.

Although Fox continued to champion his ideas through numerous papers, popular articles, books, and talks until he died in the summer of 1998, his work is now almost universally dismissed. …

The scientific community may have reacted too harshly. … But because of his unsubstantiated claims, most scientists have avoided further experimentation on proteinoids.” (Christopher Wills & Jeffrey Bada, The Spark of Life: Darwin and the Primeval Soup, Perseus Publishing, 2000, p54-55)

And perhaps his boldest exaggeration, though this one was off the record, was his claim that he had actually created life from non-life.

“Fox claimed that he was well on his way to creating life in the laboratory. When the German scientist Wolfram Thiemann of the University of Bremen later asked Fox, during a casual conversation in a bar, whether he had in fact created life, Fox gave a rather Jesuitical reply: “Of course I did – if you define life the way I do!”” (Christopher Wills & Jeffrey Bada, The Spark of Life: Darwin and the Primeval Soup, Perseus Publishing, 2000, p52)

Unfortunately, Fox seems to have defined a lot of terms his own way.

 

[DNAunion]

Not All Microspheres are Proteinoid Microspheres

Finally, one needs to note that not all articles pertaining to microspheres involve those made from proteinoids. The term microsphere now has a much broader meaning (including small plastic beads used by biochemists and small capsules used to deliver drugs or other such substances). Anyone claiming to have found numerous recent articles on microspheres (to support a claim that proteinoid microspheres have not been dismissed by mainstream scientists) should be asked to provide valid material from the article: a title containing the word “Microsphere”, but without the word “Proteinoid” in it, is insufficient.

Are Proteinoid Microspheres Actual Living Cells?

No, as should be clear after reading the above material. The following are some statements regarding the fact that proteinoid microspheres are not actual living cells.

"Compared to coacervates and lipid-bilayer vesicles, proteinoid microspheres are a relatively homogenous population. Considering the extremely small probability that some particular collection of molecules contained within a bounded system would be just the right mixture to progress toward the living state under the best conditions, the chances would be significantly lower in the case of proteinoid microspheres." (emphasis added, Charlotte J. Avers, Molecular Cell Biology, Benjamin/Cummings Publishing, 1986, p773)

“[Sidney Fox] showed that heating dry mixtures of amino acids and then mixing the resulting polymers with water will form small spherical bodies. These proteinoid microspheres possess certain characteristics of living systems.” (emphasis added, Cleveland P. Hickman Jr., Larry S. Roberts, & Allan Larson, Integrated Principles of Zoology: Tenth Edition, WCB McGraw-Hill, 1996, p36)

“There is no way to know whether proteinoids may have been the ancestors of the first cells or whether they are just interesting creations of the chemist’s laboratory.” (emphasis added, Cleveland P. Hickman Jr., Larry S.Roberts, & Allan Larson, Integrated Principles of Zoology: Tenth Edition, WCB McGraw-Hill, 1996, p36)

“The first living organisms were … autonomous membrane-bound units with a complex functional organization that permitted the essential activity of self-reproduction. The primitive chemical systems we have described [such as proteinoid microspheres] lack this essential property. The principal problem in understanding the origin of life is explaining how primitive chemical systems [such as proteinoid microspheres] could have become organized into living, autonomous, self-reproducing cells.” (emphasis added, Cleveland P. Hickman Jr., Larry S. Roberts, & Allan Larson, Integrated Principles of Zoology: Tenth Edition, WCB McGraw-Hill, 1996, p36)

“Scientists have synthesized several different protobionts, which are assemblages of abiotically produced (that is, not produced by organisms) organic polymers. They have been able to recover protobionts that resemble living cells in several ways, thus providing clues as to how aggregations of complex nonliving molecules took that “giant leap” and became living cells. ... [Proteinoid] microspheres are a type of protobiont formed by adding water to abiotically formed polypeptides. … It is a major step (or several steps) to go from simple molecular aggregates such as protobionts to living cells. Although much has been learned about how organic molecules may have formed on primitive Earth, the problem of how pre-cells evolved into living cells remains to be solved.” (emphasis added, Eldra Pearl Solomon, Linda R. Berg, & Diana W. Martin, Biology: Fifth Edition, Saunder College Publishing, 1999, p427-428)

 

[DNAunion]

“The general problem of peptide formation from amino acids in aqueous solution is the thermodynamically and kinetically unfavorable process of water removal in a condensation reaction. …

The most obvious way to avoid the problem of water removal in aqueous solution is to let the solvent evaporate (a facile process on a hot, primitive earth in lakes, lagoons, and coastal regions) and to expect that further heating on solid ground would lead to melting of the residue. Experiments carried out by [Sidney] Fox have shown that such a melt of amino acids produces a kind of polymer – called in the initial enthusiasm ‘proteinoids’ – provided that acidic or basic amino acids are present in excess. Temperatures for this process have to be within 130-160 [degrees] C to allow melting without decomposition. If concentrated phosphoric acid were present, the temperature could be lowered considerably, but under prebiotic conditions it is highly unlikely that the amounts of phosphoric acid required would have been present. Three other arguments also contradict strongly the relevance of such melt reactions for the formation of peptides on the primitive earth: first, all processes producing amino acids from simple atmospheric components never lead to an excess of acidic or basic amino acids; second, the mixture of amino acids in these experiments was chemically pure but all of the inorganic matter contained in the primordial ‘soup’ rather would dominate the residue after evaporation and form a serious obstacle for this process; and third, the so-called ‘proteinoids’ are mainly polymers containing only very small amounts of peptide bonds, and they do not deserve the name.” (Bernd Michael Rode, Peptides and the Origin of Life, Peptides 20, 1999, p775-776)

 

[DNAunion]

"These proteinoids, without nucleic acids to act as informational molecules, could not have had genetic continuity; thus, it is possible that extrensive trial and error occurred, leading to short-lived structures. Only after the origin of the genetic code, determined by the sequence of bases in nucleic acids, could a self-perpetuating organism have arisen in which the laws of natural selection had begun to operate." (E. D. P. DeRoberts & E. M. F. DeRoberts, Cell and Molecular Biology: Seventh Edition, Saunders College Publishing, 1980, p128-129)

 

[DNAunion]

DNAunion: Lucaspa, your first post is nothing but a string of references.

Unfortunately, we've seen that we can't trust what you say about references. Remember how you listed three articles from Science that you claimed showed that PROTEINS were formed at hydrothermal vents... yet not one of the articles showed that?

 

[DNAunion]

DNAunion: And why are your references so old? You know, scientists used to write articles about the existence of a luminiferous ether too...but not anymore.