Matter contrives to be alive.
Life is universal like elementary particles--protons, neutrons, and electrons or in some places antiparticles of the matter. Of all the elements hydrogen, oxygen, nitrogen, and carbon have properties on which life depends. Matter has inherent property of duplication under certain specific conditions. Synergistic collaboration of non-linear processes led to auto-organization of molecules in specific-stearic position through intermolecular and intramolecular bonds, and the outcome of their integrated functions is the living phenomenon, such as multiplication, growth, and metabolic activities. Bahadur and Ranganayaki reported the formation of autoreplicative units, " Jeewanu," in an irradiated sterilized aqueous mixture of some inorganic and organic substances.
The theory of molecular or chemical evolution postulated by Oparin (1) and Haldane (2) created much interest in origin of life. Molecular evolution refers to ultimate formation of molecules by chemical transformation of substances with the condition that earliest living systems were formed of the same materials of which the present day living systems is made up of. (3)
A number of workers have studied abiogenesis of various compounds of biological interest, such as amino acids, nucleic acid bases, sugars, and phospholipid-like materials in a laboratory simulated atmosphere. (4,5,6,7,8,9)
One of the most fundamental problems of origin of life is to study physico-chemical conditions, which might have transformed lifeless material into living systems.
Definition of a Living System
According Pierie, (10) "a rigid division between living is not possible and life is not a definable quality but a statement of our attitude of mind towards a system." Haldane (11) defines a living system as a "self-perpetuating pattern of chemical reaction." Bernal (12) said that a living system is "embodiment within a boundary of self maintaining chemical process." Konikova (13) suggested "a living system is a chemical substance or a complex which by a process of chemical reactions with substance of its surroundings, accomplishes its reproduction and development " Horowitz (14) attributes three essential properties to be a living system--self-reproduction, mutation, and heterocatalysis. He postulated the concept of "heterotrophic hypothesis," assuming a reducing prebiotic atmosphere. The formation of various proto-cell-like models, such as "Coacervates" by Oparin, and "Microspheres" by S. W. Fox, in a laboratory-simulated prebiotic atmosphere was studied.
Catalytic Properties of Minerals and Autotrophic Hypothesis
Bernal, (15) Smirnova, (16) and Cairns-Smith (17) emphasized the role of catalytic properties of inorganic catalysts in the synthesis of earliest living systems. Hartman (18) proposed a mechanism of autotrophic origin in which clays, metals, disulphide, dithiols, ultraviolet radiation, and cyanide ion form a primitive metabolic system, which can fix CO2 and N2 and could evolve in a simple environment. He said that Krebs cycle is the most elementary form of metabolism. Bahadur et al. postulated an autotrophic hypothesis based on catalytic properties of minerals in cell-sized domains. (19,20,21)
Nowadays, many workers believe that problem of origin of life is not of abiogenesis but of chemical energetics.
Source of Energy
Various types of energy sources were used in the abiogenesis of biogenic compounds in the possible prebiotic atmosphere, such as electric discharges, ultraviolet, and thermal energy by many workers. Thermodynamical considerations also favor the use of weaker sources of energy for the formation of biogenic molecules, such as amino acids and peptides, as for a strong source of energy, e.g. short UV or electric discharge, is employed and it will quickly breakdown the molecules formed as suggested by Hull. (22) Bahadur said that the problem is to find out the weakest source of energy that can synthesize the molecules of biological interest because only those molecules can remain stable for a longer period of time. According to Bahadur, solar energy seems to be most appropriate source of energy for this purpose. (2)
Photochemical Synthesis of a Self-Sustaining System
Bahadur et al. (3,19,23,24) observed the photochemical formation of protocell-like microstructures in a sunlight-exposed sterilized aqueous mixture of ammonium molybdate, diammonium hydrogen phosphate, biological minerals, and formaldehyde. These microstructures were named as "Jeewanu" (a Sanskrit word for life). They multiply by budding, grow from within and show metabolic activities in them. Their microscopic examination reveals that they are spherical in shape, have a double-walled boundary, and an intricate internal structure. They have been analyzed to contain various materials of biological interest--amino acids that are present in free as well as in peptide combination, (19,23,25) nucleic acid bases as purines as well as pyrimidines, (23,26) sugars as ribose as well as deoxyribose, (19) and phospholipid-like material (27) in them. The presence of various enzyme-like activities, phosphatase, ATP-ase, ester-ase, and nitrogen-ase (19,23,28,29) have been observed in the Jeewanu mixture. The EPR spectra of Jeewanu showed the presence of ferredoxin-like material in them. (30) Photochemical reduction of C[O.sub.2] (31) and [N.sub.2] was studied using [C.sup.14] and [N.sup.15]. Further, using [D.sub.2]O it was found that [H.sub.2] evolved by photolytic decomposition of water is utilized in photochemical fixation of C[O.sub.2] and [N.sub.2]. (32)
Synergistic Collaboration of Non-linear Processes: A Functional Approach to Origin of Life
Physico-chemical factors leading to auto-organization and replication at the molecular level may reveal some important information about the transition of lifeless material into living systems. But molecular dynamics of self-organization is difficult to study due to its non-linear nature. According to Bahadur, (3,24) matter has an inherent property of duplication under suitable conditions and a system of matter in equilibrium has an inherent property of adaptability. The precursors of earliest living systems were smaller molecules; duplication probably would have been possible with the help of quantum mechanical resonance stability force and inter-molecular interactions. In the prebiotic atmosphere, inorganic pyrophosphates formed by photo-phosphorylating reactions and enrichment of enantiopure molecular conformations provides a thermodynamical driving force for the evolution of biogenetic process. (32) But, molecular dynamics of self-organization is difficult to study due to its non-linear nature. Bahadur suggested a functional approach to origin of life. (33)
According to Nicolis (34) and Santoli, (35) based on deterministic chaos and internal noise at nanometer level can supply the basis for interpretation of information processing at molecular level.
The earliest living system was possibly photoautotrophic in nature. It had the ability of photolytic decomposition of water, and [H.sub.2] thus evolved and was utilized in photochemical fixation of [N.sub.2] and C[O.sub.2].
Cairns-Smith (36) remarked "perhaps the earliest photosynthesing organisms were a subclass of Jeewanu, a kind whose structure was guided to some extent by inorganic crystal genes.
In the prebiotic atmosphere possibly photophosphorylating reactions leading to formation of inorganic pyrophosphate), formation of enantiopure molecules led to synergistic collaboration of non-linear processes, which triggered the self organization of molecules in specific-stearic position through some inter-molecular and intra-molecular interactions, and the outcome of their integrated function is the living phenomenon.
"Life is a state of being of a self-sustaining system capable of metabolic activities, growth and multiplication" (where metabolic activities mean any series of physico-chemical reaction happening within a system and environment, which sustains the form in time and space,
* the growth means an increase in size from within by actual synthesis of material, and
* the multiplication means the increase in the number of units from the parental system).
(This work was supported by a grant from University Grants Commission, Bhopal (M.P.), India. I would like to thank Dr. (Mrs.) S. Ranganayaki and Dr. J. L. Gupta, Department of Chemistry, University of Allahabad--211002 (U.P.), India, for valuable discussion)
(1.) Oparin, A. I. (1953). Origin of life. (S. Morgulis, Trans.). New York: Dover Publication.
(2.) Haldane, J.B.S. (1929). The origin of life. Rationalist Annual, 3.
(3.) Bahadur, K. (1964). Conversion of lifeless matter into living system. Zentrablatt fur Bacteriologie, 118(2), 671.
(4.) Bahadur, K. (1954). Photosynthesis of amino acids from paraformaldehyde and potassium nitrate. Nature, 173,1141.
(5.) Miller, S. (1955). Production of some organic compounds under possible primitive conditions. J. Amer. Chem. Soc., 77, 235- 61.
(6.) Pavlovskya, T. E., and Pasynskii, A.G. (1957). The origin and formation of amino acids under the action of ultraviolet rays and electric discharges. International Symposium Origin of Life on the Earth. Pergamon Press.
(7.) Reid, C. (1957). The relation between primitive and present day photobiological process International Symposium Origin of Life on the Earth. Pergamon Press.
(8.) Miller, S. L. and Orgel, L. E. (1974). The origin of life on the Earth. New Jersey: Prentice Hall.
(9.) Calvin, M., (1969). In chemical evolution. Oxford: Oxford University Press.
(10.) Pierie, N. W. (1937). In the physical basis of Life by J. D. Bernal. London: Routledge & Kegan Paul.
(11.) Haldane, J.B.S. (1954). Origin of life. New Biology,16,12.
(12.) Bernal, J. D. (1957). Problem of stages in biopoesis. International Symposium Origin of Life on the Earth. Moscow: Pergamon Press.
(13.) Konikova, A. S. (1957). On defining life. International Symposium Origin of Life on the Earth. Moscow: Pergamon Press.
(14.) Horowitz, N. W. (1945). On the evolution of biochemical synthesis. Proceedings of National Academy of Science USA, 31,153-15 7.
(15.) Bernal, J. D. (1967). The origin of life London: Weidenfeld & Nicolson.
(16.) Smirnova, A. Ya.(1957). The relationship between the minerals and organic worlds. Proc. First Intern.Sym. Origin of Life on the Earth. New York: Pergamon Press,184.
(17.) Cairns-Smith, A. G. (1966). The origin if life and the nature of the primitive gene. Journal of Theoretical Biology, 10, 53-88.
(18.) Hartman, H.(1975). Speculations on the origin and evolution of metabolism. Journal of Molecular Evolution, 4, 359-70.
(19.) Bahadur, K., et al. (1963). Preparation of Jeewanu units capable of growth, multiplication and metabolic activity. Vijnana Parishad Anusandhan Patrika, 6, 63.
(20.) Bahadur, K., et al. (1964). Synthesis of Jeewanu--Part-II: Photochemical preparation of growing, multiplying units with metabolic activities. Zentrablatt fur Bacteriologic., 117(2), 567.
(21.) Bahadur, K., et al. (1966). Synthesis of molecular associations with the properties of biological order. Zentrablatt fur Bacteriologic, 120(2), 740-752.
(22.) Hull, D. E. (1960). Thermodynamics and kinetics of spontaneous generation. Nature, 186, 693-695.
(23.) Bahadur, K., and Ranganayaki, S. (1970). Photo chemical formation of self-sustaining coacervates. Journal of British Interplanetary Soc., 23, 813.
(24.) Bahadur. K. (1967). Synthesis of Jeewanu the protocell. Zentrablatt fur Bacteriologic 121(2), 291.
(25.) Briggs, M. H. (1965). Experiments on the origin of cells. Space Flight, 7 (4), 129.
(26.) Ranganayaki, S., Raina, V., and Bahadur, K. (1972). Detection of nucleic acid bases in photochemically synthesised self-sustaining coacervates. Journal of British Interplanetary Soc.,5, 277.
(27.) Singh, Y. P. (1975) Studies in abiogenesis of phospholipid. Doctor of Philosophy Thesis, chemistry department, University of Allahabad, India.
(28.) Singh, R. C. (1973). Studies in abiogenesis of enzyme-like material. Doctor of Philosophy Thesis, chemistry department, University of Allahabad, India.
(29.) Bahadur, K and Gupta, V. K. (1984). Histochemical detection of acid phosphatase-like activity in Jeewanu, the abiogenically formed proto- cell-like molecular associations. In G. K. Manna and U. Sinha (Eds.), Perspectives in Cytology & Genetics, 45, (pp. 205-208). Bhagalpur University, Bhagalpur, India.
(30.) Rao, K. K. (1978). Carbon dioxide reduction and nitrogenase activity in organo- molybdenum microstructures. Experientia, 37. Biophotolysis of water for hydrogen production and artificial catalytic systems. Abstract presented at the BASE Symposium, Madurai, India.
(31.) Smith, A., Folsome, C., and Bahadur, K (1981). Carbon dioxide reduction and nitrogenase activity in organo-molybdenum microstructures. Experientia, 37, 357-359.
(32.) Pal, N., et al. (1986). Inorganic pyrophosphate synthesis after a short light flash in chromatophores from rhodospirillum rubrum. Photobiochemistry and Photobiophysics, 11,189-196.
(33.) Bahadur, K., et al. (1980). A functional approach to the origin of life problem. National Academy of Sciences, India, Golden Jubilee Commomeration Volume, 1-17.
(34.) Nicolis, J. S. (1985). Dynamics of hierarchical systems. Berlin: Springer.
(35.) Santoli, S. (1993). Nanobiolgical principles and the origin of life. Nanobiology, 2, 201- 214.
(36.) Cairns-Smith, A.G. (1982). Genetic takeover. Cambridge: Cambridge University Press.
Department of Zoology,
C.M.D. Post Graduate College, Bilaspur-495 001 (Chhattisgarh.), India.
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