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роза красная морда большая

systemity


САМООРГАНИЗУЮЩИЕСЯ СИСТЕМЫ


English translation of my 1984 paper on the origin of life on Earth. Part I
роза красная морда большая
systemity
View on Lipids of Microorganisms from the Standpoint of Prebiotic and Biological Evolution* PART I

Leonid Andreev


Part II: https://systemity.livejournal.com/4661607.html

Original paper "View on Lipids of Microorganisms from the Standpoint of Prebiotic and Biological Evolution" published in: Voprosy Evolutsii Bakterij (Evolution of Bacteria), USSR Academy of Sciences, Center for Biological Research, Institute of Biochemistry and Physiology of Microorganisms, Pushchino, 1984, pp. 93-119 (https://www.dropbox.com/s/tx666ilga018yvt/OriginOfLifeRus.pdf).
This translation was first published in 2004 on the company website of Equicom, Inc. which is no longer online.

Contents:

• Specificity of lipids as an object of molecular biological studies
• Cellular level of lipid studies
• The concept of polylipids
• Interaction between polylipids and proteins
• Role of fatty acid residues
• Enzymes and coenzymes
• Principle of quasi-equilibrium of biosynthesis of bacterial lipids
• On the origin of life on Earth
• Macromolecular chronometry
• Molecular model of a protobiont
• Conclusions


Specificity of lipids as an object of molecular biological studies

Modern molecular biology incorporates a number of research areas dealing with substances and processes of general biological significance. Those areas of research, stimulated and inspired by the efficacy of the currently available physico-chemical methods, considerably differ in methodologies and – what is especially important – due to their specific developmental backgrounds, they have different levels of relationship with cellular biology.

When that relationship is lost or is not yet strong enough, it is often understood as an indication that some of the problems of physical chemistry of bioorganic molecules may be as broad and complex as the issues encountered with in the study of the functioning of live cells. This concerns particularly investigations of biological macromolecules that are functionally active outside the cells that synthesize them. That kind of misconception is not accidental. The awareness of the fact that, despite a theoretically possible large variety of structural and functional organizations of biopolymers, the Nature has only a limited number of their variants, impedes the advance of researchers in physics and chemistry of the functionality of such molecules, as it makes them divert to working on problems which require qualitatively different approaches and expertise and force them to study such properties of organisms which require deep empirical knowledge. This is a psychological reason that explains why many molecular biologists at least sympathize with, if not fully concede to, the thesis that the notion of ‘cell’ “has become a brake on the progress toward the understanding of live structures at the molecular level” and that “one may stop treating the cell as a biological unit but consider it as merely one of the stages of a complex chain of transformations” [16]*.

In practice, such views may seem to be justified as the attempts not to limit oneself to the “barest necessities” of evolutionary biology and “biological purposefulness” and, instead, consider the cell to be “merely one of the stages of a complex chain of transformations” may often be helpful in extensive fundamental investigations in molecular biology, leading to innovative approaches to various aspects of the functioning, systematics and evolution of live organisms. A classical example of such fundamental works in molecular biology that already by now have significantly contributed into the progress in evolutionary biology, is the method of macromolecular chronometry developed a quarter of a century ago [34] based on physico-chemical, rather than biological, logic.

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* Rendition is based on the Russian edition of the source book.


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English translation of my 1984 paper on the origin of life on Earth. Part II
роза красная морда большая
systemity
View on Lipids of Microorganisms from the Standpoint of Prebiotic and Biological Evolution. PART II

Leonid Andreev


Part III: https://systemity.livejournal.com/4661963.html
Part I: https://systemity.livejournal.com/4661364.html


Original paper "View on Lipids of Microorganisms from the Standpoint of Prebiotic and Biological Evolution" published in: Voprosy Evolutsii Bakterij (Evolution of Bacteria), USSR Academy of Sciences, Center for Biological Research, Institute of Biochemistry and Physiology of Microorganisms, Pushchino, 1984, pp. 93-119 (https://www.dropbox.com/s/tx666ilga018yvt/OriginOfLifeRus.pdf).
This translation was first published in 2004 on the company website of Equicom, Inc. which is no longer online.

Enzymes and coenzymes

The membrane system of prokaryotic organisms lacks an expressed anatomic compartmentalization of membrane enzymatic processes, which is the key difference between eukaryotic and prokaryotic organisms. The prokaryotic type of membrane system organization causes tremendous difficulties for the cellular level regulation of the membrane enzymatic processes which involve same coenzymes. Strangely, this peculiarity of bacteria has been getting very little attention [3]. Based on molecular weights of the most widely distributed coenzymes that supply membrane-immobilized enzymes of small reacting molecules, such as protons, C1- and C2- compounds, etc., it can be easily established, by the Einstein diffusion equation, that  at physiological temperatures, those enzymes cover within a second the distances that several times exceed the length of a bacterial cell. Knowing that, it is hard to understand, for instance, the secrets of coordination of the activity of dozens of types of enzymes, whose functioning requires  pyridine nucleotide carriers in specific concentrations strictly determined by a current physiological state of the cells.

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English translation of my 1984 paper on the origin of life on Earth. Part III
роза красная морда большая
systemity
View on Lipids of Microorganisms from the Standpoint of Prebiotic and Biological Evolution. PART III

Leonid Andreev


Part II: https://systemity.livejournal.com/4661607.html

Original paper "View on Lipids of Microorganisms from the Standpoint of Prebiotic and Biological Evolution" published in: Voprosy Evolutsii Bakterij (Evolution of Bacteria), USSR Academy of Sciences, Center for Biological Research, Institute of Biochemistry and Physiology of Microorganisms, Pushchino, 1984, pp. 93-119 (https://www.dropbox.com/s/tx666ilga018yvt/OriginOfLifeRus.pdf).
This translation was first published in 2004 on the company website of Equicom, Inc. which is no longer online.

Macromolecular chronometry

It would seem that this logical deadlock could be resolved by comprehensive investigation of regularities in the evolution of those macromolecules which perform same functions in evolutionarily distant contemporary organisms. With the fundamental capabilities created by molecular biology methods, it is possible now not only to investigate evolutionary relations between various organisms but also to estimate a relative time point of their divergence, i.e. evolutionary distances. The idea of the “molecular evolutionary clock” was first proposed by Zuckerkandl and Pauling [34] in 1965. It is based on the fact of existence of a great variety of macromolecules that, having different sequences of monomers, are capable of performing same functions. Consequently, mutational changes in proteins and nucleic acids can provide a measure of the evolution time. Woese [33] recently made a detailed analysis of the results obtained with the use of the molecular chronometry method and discussed the ways for further improvement of the method and overcoming its limitations.

For instance, one of the major limitations of the method is caused by the fact that the relative speed of homologous macromolecular clocks can be different in different organisms. Also, in bacteria, an intensive interspecies transfer of genes with totally different evolutionary backgrounds may contribute into different genealogy of macromolecules of one and the same organism. Both of those limitations can be resolved in one or another way. For instance, it was shown that the use of two independent molecular clocks – cytochrome c and ribosomal RNA – provided consistent data on purple synthesizing bacteria [22]. Phylogenetic structures based on molecular chronometry studies [25, 29] attract a lot of interest in biologists of various areas of specialization, and there is a hope that this method can help to develop objective criteria for evaluation of evolutionary relations between various groups of organisms. Nonetheless, the areas in which molecular chronometry is either ineffective or insufficiently effective include, first and foremost, the issues of prebiotic evolution, emergence of life and the functioning of early life forms. It is also important  to realize that the discovery of the paths of evolution of life on Earth is not an answer to the question about the reasons for the choice of those paths.


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