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Nahle, N. (2005). Reproduction of Bionts. Obtained on (month) (day), (year).
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BACKGROUND AND THEORY
Could life exist without reproduction? Yes, indeed, the erythrocytes of mammals do not self-reproduce; even thus, they experience life through about six months. As red blood cells do not posses mitochondria, they do not posses a steady mechanism for programmed cell death; here, the substances produced by other cells with mitochondria take part; those substances are put in contact with the red blood cells’ membranes and introduced within the cytoplasm and then it starts the process of programmed cell death (Apoptosis). (Bratosin D. et all. 2001).
Does this mean that the erythrocytes are immortal living beings? No, but that they die when getting about six months old; the Apoptosis is used to kill the substandard cells, cells with an inconsistent metabolism, or to maintain the stability in the number of this species of blood cells. (Ham, Arthur W. J. B. Histology. 1974).
If we put a cockroach alive in a blender and we blend it, then we take all the bits of the cockroach -without lack of a single fragment- and we place them together into a Petri Dish, and then we put the mix to incubate, we will never obtain a living cockroach from the cockroach remains. Now, suppose that we can place together all the cockroach’s fragments to shape the complete body of the blended cockroach and we put it to incubate in its respective Petri Dish... We will never obtain a cockroach alive; besides, our reconstructed cockroach would be so unstable that it will disintegrate quickly. I want to prove with this that life only has had continuity from the first biont that existed on our planet about 3.9 billion years ago. Life is non-recoverable. (Nahle, N. 1999). We must to keep this information in mind for considering the subsequent arguments:
Empirically, we have confirmed that the spontaneous synthesis of ribozymes in nature is impossible. As in the case of our blended cockroach, they simply do not synthesize themselves spontaneously and we must to take part like direct and absolute activators and operators of the process. What is more, the autopoiesis simply is not applicable in the synthesis of nucleic acids, even when we placed all the small pieces of molecules in an appropriate medium; if an operator does not take part on it, the processes of nature will never generate molecules of nucleic acids spontaneously. However, it is feasible the generation of biomembranes through spontaneous processes in nature, therefore, while the radiations act as activators in the spontaneous synthesis of catalytic proteins, they act as a destructive force in the case of nucleic acids. If there were not an operator acting on the process, the nitrogenous bases would never assemble with Ribose spontaneously. Catalytic proteins were the operators when Abiogenesis started. For example, prions can duplicate themselves without an external operator. This is the reason because we are afraid of prions.
Then, how the first bionts reproduced themselves? We have concluded that they did not reproduce themselves as the contemporary cells do, by means of cell division. As an alternative, we have deduced that the first bionts could be large biomembranes stretched out on humid grounds, or at the bottom of small pools or watery layers, wherein the biomembranes associated with the accumulated substances in the cracks and holes of the floor. There, the biomembranas might interact with those substances for maintaining thermal and structural steady states. In addition, we thought that the Electrodynamic Field generated by an Electrochemical Gradient already could be manifested spontaneously in amphiphilic bilayered biomembranes.
The rest of the process would be developed by simple chemical affinity. The autocatalytic molecules compatible to the nucleotides could use these to store information and at the same time the new simple chained nucleotides could regulate the production of catalytic molecules that maintained the thermal stability of the whole biont during well-defined periods. Then, the nucleic acids were synthesized by a mere biochemical event, without a final purpose to create complete genomes. The first molecules of nucleic acid were quite simple and were synthesized according to the immediate necessities of bionts established by large biomembranes covering gaps of the irregular humid grounds where they stretched out. As the necessities for the storage of biochemical information were greater, the catalytic molecules of those bionts would add more and more nucleotide sequences to the primary chain, forming more and more complex chains. This one is the most reasonable explanation to the presence of apparently useless genes in the genomes of all living beings and to the presence of bacterial plasmids.
It is more feasible that the first biont did not reproduce itself by means of Mitosis or Meiosis, but that they generated something looked like vesicles that separated from larger biomembranes as these grew up in volume. Hundreds, thousands, millions, or perhaps billions of living vesicles just limited by their own membranes, sprouted from the large biomembranes, resembling to the reproductive process of some current bacteria and yeasts, but devoid of nucleic acids and/or ribozymes. (Campbell. 1999). One -or perhaps many- of those living vesicles devoid of genetic material could display the chemical affinity and the correct molecular structures demanded to be capable of taking compounds from the environment for synthesizing molecules of RNA (probably ribozymes) which were able to store the information of those archeobionts and to generate a codified selfreplication and reverse transcriptases.
This model disentangles most of the uncertainties that cannot be deciphered by the classic hypothesis of Oparin-Miller, the hypothesis of RNA-world and the hypothesis of Manifold-Meteorites Impacts.
Without doubt, this theory is perfectly testable by experimentation or through the hypothetical-deductive analysis applied to the observation of the current facts and discoveries that are clarifying the process of Abiogenesis on Earth.
When we study the topic of the Origin of Living Beings on Earth the scheme proposed is about a nutritious broth where prebiotic organic molecules were catalyzed spontaneously to give origin to microspheres, coacervates, protobionts and, last, to living cells.
The first problem that arises from this proposal relates with the abiotic synthesis of prebiotic compounds and the maintenance of its structural integrity in a supersaturated atmosphere as it would be it a nutritious broth like the proposed one in the classic hypothesis.
The fact that a biomembrane formed spontaneously is not a problem, given that it already has been verified experimentally that the biomembranes can spontaneously structured even under microgravity and ordinary void conditions, for example, in the neighborhood of the terrestrial nebula. This also would be highly possible in an atmosphere saturated by organic and inorganic molecules.
The true problem is originated when the hypothesis of the nutritious soup supposes the existence of protobiontes that not yet experienced life immersed in that soup! It implies the very serious problem of the asymmetry that had to exist spontaneously, so that the just-formed biomembranes could maintain an internal hypertonic solution, given that they were situated into a hypothetical hypertonic surrounding environment. Examining the subject, we obtain three possible alternatives:
1. Hypotonic Model. Protobionts had a hypotonic internal environment in relation to the surrounding medium. This means that the internal medium enclosed by the biomembrane would contain a concentration chemical substance smaller than the concentration of chemical substances at the medium outer to the biomembrane.
This would generate the serious problem of the osmotic collapse (plasmolysis) since the substances would move spontaneously towards the interior of the vesicles and these would lose their contained water, drying themselves like raisins. In order to start on, the adjustment of such prebiotic systems would be impossible because the high concentration of oxidizing substances in that imaginary nutritive soup, which would not allow any spontaneous synthesis of biomembranes. The substances would tend to move from the environment towards the inside of the protobiont, whereas the water would tend to leave out from the protobiont. Remember the experiment on osmoregulation, wherein it was exemplified the form by which the molecules always move spontaneously from the side of higher concentration of a product towards the side of lower concentration of products, through a semipermeable membrane of cellulose, which maintains a osmotic balance between both sides of the semipermeable membrane. You know that this is due to the difference in the osmotic pressures at each side of semipermeable membranes.
2. Hypertonic Model. Protobionts would have a hypertonic internal solution with respect to the nutritious soup. That is to say, that the internal environment of the protobionts would have a concentration of substances greater than the concentration of substances in the nutritious soup or outer environment.
For this case, an osmotic catastrophe would happen due to the uncontrollable spontaneous absorption of water by the protobionts until they would burst out (lysis).
3. Isotonic Model. Protobionts would have an isotonic internal environment with respect to the nutritious broth. This means that the internal solution of the vesicles would have a concentration of substances equal to the substance concentration of the external environment. This environment would be the most appropriate for the stability of protobionts.
From these three models, we conclude that the primitive biomembranes had a mechanism of active transport, an incident that could have happened spontaneously.
The isotonic model would facilitate the chemical evolution of protobionts, unlike the other scenarios, which would absolutely prevent it. Nevertheless, it was not possible that the vesicles were globules simply surrounded by amphiphillic bilayered membranes because the first vesicles were not able to perform an active transport. which implies several steps generated by chemical affinity between the miscellaneous organic structures entirely produced by autocatalytic processes.
Then, the model of tiny dynamic spheres comes down in each one of the three proposed models. The only solution is the Vaneechoute’s model, which is the version of a large membrane extended on grounds of aquatic environments, covering cracks and gaps filled with complex organic substances that could communicate on both sides of the biomembranes. This way, by chemical affinity, some of the proteins that tried to get through those amphiphillic bilayered membranes would attach spontaneously to these, remaining as an advisable transporter of other substances.
Another very important thing was the spontaneous synthesis of biomembranes with the appropriate molecular structures that offered the minimum physical characteristics that induced them to experience an interaction between charged particles through photons, to be exact, to experience an Electrodynamic Field, Electrochemical Field, or Biotic Field.
I have the good news for you about the existence of modern living beings that do not have mitochondria or chloroplasts and that, even so, have cell membranes with the abovementioned physical characteristics. These cells can be true living fossils of those primitive vesicles, which budded from the main membranous mass. The sole difference between the archeobionts and these modern cells is the possession of Nucleic Acids. These modern living beings are Archaeobacteria, Cyanobacteria and Bacteria. The existence of these living energy batteries gives us important evidences that corroborate our proposal on the Origin of Life on Earth, or Abiogenesis.
The only uncertainty in this model would be the mechanism through which the vesicles were wrapped absolutely by a biomembrane; although we could deduce that, when finishing the development of a vesicle, it was closed on itself through the same biological mechanism used by some bacteria and yeasts when budding; nevertheless, the protobionts were vesicles devoid of nucleic acids.
Bratosin D. et all. Programmed cell death in mature erythrocytes: a model for investigating death effector pathways operating in the absence of mitochondria. National Library of Medicine. 2001; Vol. 8 (12): pp.1143
Campbell, Neil A. et al. Biology. Addison Wesley Longman, Inc. 1999, Menlo Park, CA
Guy Riddihough. The Other RNA World. Science, Vol 296, Issue 5571, 1259 , 17 May 2002.
Ham, Arthur W. J. B. Histology. Lippincott Company. 1974. New York, NY.
Lang, F., Gulbins, E., Szabo, I., Lepple-Wienhues, A., Huber, S. M., Duranton, C., Lang, K. S., Lang, P. A., Wieder, T. J. Cell volume and the regulation of apoptotic cell death. Taken from: Mol Recognit. Obtained on August 14, 2005. Year of publication: 2004 Sep-Oct;17(5):473-80. http://www.ncbi.nlm.nih.gov.
Nahle, Nasif. What is Life? http://biocab.org/Life.html. Obtained on August 14, 2005.
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