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  • 1
    Keywords: Physics ; Philosophy of nature ; Life sciences ; Evolution (Biology) ; Astronomy ; Astrophysics ; Astrobiology ; Physics ; Astrobiology ; Extraterrestrial Physics, Space Sciences ; Astronomy, Astrophysics and Cosmology ; Evolutionary Biology ; Biogeosciences ; Philosophy of nature ; Springer eBooks
    Pages: : digital
    ISBN: 9789400716278
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 3 (1991), S. 389-392 
    ISSN: 0899-0042
    Keywords: chirality ; origin of life ; Bose condensation ; organic superconductivity ; electroweak interaction ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We review a recent paper20 in which a specific enhancement factor (i.e., a phase transition into a condensed Bose mode) is proposed to account for the observed amplification of the ground state energies of the L- and D-amino acid enantiomers; the difference between these energies is assumed to be due to the neutral parity-violating electroweak interaction. This physical effect initially shifts the enantiomer energies by about 3 × 10-19 eV. The proposed phase transition is characterized by a critical temperature Tc, which may be studied theoretically by enlarging the standard electroweak theory to include either the top quark or supersymmetry21. Possible experimental means of finding Tc are discussed.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 6 (1994), S. 165-168 
    ISSN: 0899-0042
    Keywords: chirality ; chemical evolution ; phase transitions ; optical activity ; spontaneous symmetry breakdown ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We discuss the origin of the chirality of protein amino acids from the point of view of a phase transition from a racemic mixture into an optically pure state. We assume that Bose-Einstein condensation may act as an amplification mechanism. The original theory is due to Salam. We suggest a new role for the phase transition. Following Quack we distinguish parity violation of two kinds (de facto and de lege symmetry breaking). While the Salam phase transition corresponds to parity violation of the second kind (de lege), the phase transition we discuss in this work corresponds to parity violation of what we may call a third kind. This is suggested by recent experimental phenomena which correlate chiral symmetry breaking and pattern formation (spontaneous symmetry breaking that separates an initial racemic mixture into right- and left-handed space domains by means of a substrate). Tentative comments are given on the eventual design of possible experiments that may test this new hypothesis. © 1994 Wiley-Liss, Inc.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1573-0875
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Journal of biological physics 20 (1995), S. 315-330 
    ISSN: 1573-0689
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract A review is presented within the framework of the theory of evolution, after it has been extrapolated from the population level to the cellular and molecular levels. From Darwin's seminal and persuasive insight - the theory of common descent - we assume, with him, that “probably all the organic beings which have ever lived on this earth have descended from some one primordial form, into which life was first breathed” [1]. We are now aware that this primordial cell may have been a protocyanobacterium, but it has often been called ‘a last universal ancestor’, a ‘breakthrough organism’, or a ‘progenote’, a term introduced by Woese [2] which has gained wide acceptance. Strictly speaking, in the ‘intermediate period’, ranging from the first living cell to the progenote, life may have evolved in the absence of significant diversity, effectively as a single phylum, incorporating organisms whose genetic systems were already based on DNA. Earlier still, prior to the encapsulation of nucleic acids in microspheres, evolution may already have been at work on RNA molecules (the ‘RNA world’). This takes our discussion into the period of chemical evolution, a concept first put forward by Oparin [3], whose principal merit is to have formulated the underlying problem in clear scientific terms. This review does not attempt to be comprehensive. It is mainly devoted to the discussion of certain concepts that may have played a relevant role in the pathway that led to the origin and evolution of the progenote. We do not dwell on the main events of the intermediate period. The topics that we have chosen to include are: the origin of chirality of protein amino acids, the origin of translation, and the origin of the genome. We conclude with some comments on one further aspect of the evolutionary process - the development of biodiversity - by considering the origin of the first eukaryotic cell, an event which, according to the fossil record, may have preceded the evolutionary radiation in the early Cambrian by over a billion years.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Journal of biological physics 20 (1995), S. xi 
    ISSN: 1573-0689
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Journal of biological physics 20 (1995), S. xiii 
    ISSN: 1573-0689
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1573-0875
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract Our present understanding of the origin and evolution of chromosomes differs considerably from current understanding of the origin and evolution of the cell itself. Chromosome origins have been less prominent in research, as the emphasis has not shifted so far appreciably from the phenomenon of primeval nucleic acid encapsulation to that of the origin of gene organization, expression, and regulation. In this work we discuss some reasons why preliminary steps in this direction are being taken. We have been led to examine properties that have contributed to raise the ancestral prokaryotic programmes to a level where we can appreciate in eukaryotes a clear departure from earlier themes in the evolution of the cell from the last common ancestor. We shift our point of view from evolution of cell morphology to the point of view of the genes. In particular, we focus attention on possible physical bases for the way transmission of information has evolved in eukaryotes, namely, the inactivation of whole chromosomes. The special case of the inactivation of the X chromosome in mammals is discussed, paying particular attention to the physical process of the spread of X inactivation in monotremes (platypus and echidna). When experimental data is unavailable some theoretical analysis is possible based on the idea that in certain cases collective phenomena in genetics, rather than chemical detail, are better correlates of complex chemical processes.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Acta biotheoretica 36 (1987), S. 241-247 
    ISSN: 1572-8358
    Keywords: Molecular biology ; molecular genetics ; neoplastic disease ; agrobacterium tumefaciens ; Dicotyledonous plants ; Crown gall
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract I discuss the two different responses from the angiosperms to the specific molecular mechanisms of the tumor-inducing agent contained in the bacteriumAgrobacterium tumefaciens. This is done in terms of the collective variables for expressing genetic response to a continuously varying supply of energy from metabolic pathways. We are led to the conjecture that the expression of the recessive oncogenes may not be restricted to humans (retinoblastoma and osteosarcoma), but may also occur in plants (crown gall), and be expressed through a heat-shock.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Acta biotheoretica 37 (1988), S. 267-279 
    ISSN: 1572-8358
    Keywords: Genetic code ; Origin of life ; Thermophiles ; Ciliates ; Protein evolution ; Heat-shock proteins ; Gene expression ; Release factors ; Archaean
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We formulate the following hypothesis: Life's origin may have occurred during the lower Archaean at a time when the environmental temperature was higher than it is at present. Preliminary consequences of this hypothesis are studied from the point of view of molecular evolution. We restrict our attention to implications regarding the genetic code. We conclude that alternative assignment of termination codons may be understood in terms of: (a) the elevated temperatures to which the progenote may initially have been exposed; and (b) the subsequent response of its genome to the opportunity provided by the eventual loss of hyperthermal genetic expression during a thermal transition (TT) period, which was triggered off by the evolution of the dynamic Earth.
    Type of Medium: Electronic Resource
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