Addy Pross

Ben-Gurion University of the Negev, Be'er Sheva`, Southern District, Israel

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Publications (53)307.68 Total impact

  • Robert Pascal, Addy Pross
    01/2014; 5(1):3. DOI:10.1186/1759-2208-5-3
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    ABSTRACT: A sudden transition in a system from an inanimate state to the living state-defined on the basis of present day living organisms-would constitute a highly unlikely event hardly predictable from physical laws. From this uncontroversial idea, a self-consistent representation of the origin of life process is built up, which is based on the possibility of a series of intermediate stages. This approach requires a particular kind of stability for these stages-dynamic kinetic stability (DKS)-which is not usually observed in regular chemistry, and which is reflected in the persistence of entities capable of self-reproduction. The necessary connection of this kinetic behaviour with far-from-equilibrium thermodynamic conditions is emphasized and this leads to an evolutionary view for the origin of life in which multiplying entities must be associated with the dissipation of free energy. Any kind of entity involved in this process has to pay the energetic cost of irreversibility, but, by doing so, the contingent emergence of new functions is made feasible. The consequences of these views on the studies of processes by which life can emerge are inferred.
    Open Biology 11/2013; 3(11):130156. DOI:10.1098/rsob.130156 · 4.56 Impact Factor
  • Addy Pross
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    ABSTRACT: The identification of dynamic kinetic stability (DKS) as a stability kind that governs the evolutionary process for both chemical and biological replicators, opens up new avenues for uncovering the chemical basis of biological phenomena. In this paper, we utilize the DKS concept to explore the chemical roots of two of biology's central concepts-function and complexity. It is found that the selection rule in the world of persistent replicating systems-from DKS less stable to DKS more stable-is the operational law whose very existence leads to the creation of function from of a world initially devoid of function. The origin of biological complexity is found to be directly related to the origin of function through an underlying connection between the two phenomena. Thus the emergence of both function and complexity during abiogenesis, and their growing expression during biological evolution, are found to be governed by the same single driving force, the drive toward greater DKS. It is reaffirmed that the essence of biological phenomena can be best revealed by uncovering biology's chemical roots, by elucidating the physicochemical principles that governed the process by which life on earth emerged from inanimate matter.
    Journal of Molecular Evolution 03/2013; DOI:10.1007/s00239-013-9556-1 · 1.86 Impact Factor
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    Addy Pross, Robert Pascal
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    ABSTRACT: The origin of life (OOL) problem remains one of the more challenging scientific questions of all time. In this essay, we propose that following recent experimental and theoretical advances in systems chemistry, the underlying principle governing the emergence of life on the Earth can in its broadest sense be specified, and may be stated as follows: all stable (persistent) replicating systems will tend to evolve over time towards systems of greater stability. The stability kind referred to, however, is dynamic kinetic stability, and quite distinct from the traditional thermodynamic stability which conventionally dominates physical and chemical thinking. Significantly, that stability kind is generally found to be enhanced by increasing complexification, since added features in the replicating system that improve replication efficiency will be reproduced, thereby offering an explanation for the emergence of life's extraordinary complexity. On the basis of that simple principle, a fundamental reassessment of the underlying chemistry-biology relationship is possible, one with broad ramifications. In the context of the OOL question, this novel perspective can assist in clarifying central ahistoric aspects of abiogenesis, as opposed to the many historic aspects that have probably been forever lost in the mists of time.
    Open Biology 03/2013; 3(3):120190. DOI:10.1098/rsob.120190 · 4.56 Impact Factor
  • Addy Pross
    Origins of Life 11/2012; DOI:10.1007/s11084-012-9305-2 · 1.77 Impact Factor
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    Addy Pross
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    ABSTRACT: Though Darwinian theory dramatically revolutionized biological understanding, its strictly biological focus has resulted in a widening conceptual gulf between the biological and physical sciences. In this paper we strive to extend and reformulate Darwinian theory in physicochemical terms so it can accommodate both animate and inanimate systems, thereby helping to bridge this scientific divide. The extended formulation is based on the recently proposed concept of dynamic kinetic stability and data from the newly emerging area of systems chemistry. The analysis leads us to conclude that abiogenesis and evolution, rather than manifesting two discrete stages in the emergence of complex life, actually constitute one single physicochemical process. Based on that proposed unification, the extended theory offers some additional insights into life's unique characteristics, as well as added means for addressing the three central questions of biology: what is life, how did it emerge, and how would one make it?
    01/2011; 2(1):1-14. DOI:10.1186/1759-2208-2-1
  • Sason S. Shaik, Addy Pross
    01/2010; 91(5). DOI:10.1002/bscb.19820910514
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    ABSTRACT: A kinetic analysis and simulation of the replication reactions of two competing replicators-one non-metabolic (thermodynamic), the other metabolic, are presented. Our analysis indicates that in a rich resource environment the non-metabolic replicator is likely to be kinetically selected for over the metabolic replicator. However, in the more typical resource-poor environment it will be the metabolic replicator that is the kinetically more stable entity, and the one that will be kinetically selected for. Accordingly, a causal relationship between the emergence of a simple replicator and the emergence of a metabolic system is indicated. The results lend further support for the "replication first" school of thought in the origin of life problem by providing a mechanistic basis for the emergence of a metabolism, once a simple non-metabolic replicating system has itself been established. The study reaffirms our view that the roots of Darwinian theory may be found within standard chemical kinetic theory.
    Bio Systems 10/2009; 99(2):126-9. DOI:10.1016/j.biosystems.2009.10.005 · 1.47 Impact Factor
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    Addy Pross
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    ABSTRACT: Chemistry and biology are intimately connected sciences yet the chemistry-biology interface remains problematic and central issues regarding the very essence of living systems remain unresolved. In this essay we build on a kinetic theory of replicating systems that encompasses the idea that there are two distinct kinds of stability in nature-thermodynamic stability, associated with "regular" chemical systems, and dynamic kinetic stability, associated with replicating systems. That fundamental distinction is utilized to bridge between chemistry and biology by demonstrating that within the parallel world of replicating systems there is a second law analogue to the second law of thermodynamics, and that Darwinian theory may, through scientific reductionism, be related to that second law analogue. Possible implications of these ideas to the origin of life problem and the relationship between chemical emergence and biological evolution are discussed.
    Chemistry - A European Journal 08/2009; 15(34):8374-81. DOI:10.1002/chem.200900805 · 5.70 Impact Factor
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    Addy Pross
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    ABSTRACT: One of life's most striking characteristics is its purposeful (teleonomic) character, a character already evident at the simplest level of life – a bacterial cell. But how can a bacterial cell, effectively an aqueous solution of an assembly of biomolecules and molecular aggregates within a membrane (that is itself a macromolecular aggregate), act purposefully? In this review, we discuss this fundamental question by showing that the somewhat vague concept of purpose can be given precise physicochemical characterization, and can be shown to derive directly from the powerful kinetic character of the replication reaction. At the heart of our kinetic model is the idea that the stability that governs replicating systems is a dynamic kinetic stability, one that is distinctly different to the thermodynamic stability that dominates the inanimate world. Accordingly, living systems constitute a kinetic state of matter as opposed to the thermodynamic states that dominate the inanimate world. Thus, the model is able to unite animate and inanimate within a single conceptual framework, yet is able to account for life's unique characteristics, amongst them its purposeful character. As part of that unification, it is demonstrated that key Darwinian concepts are special examples of more general chemical concepts. Implications of the model with regard to the possible synthesis of living systems are discussed. Copyright © 2008 John Wiley & Sons, Ltd.
    Journal of Physical Organic Chemistry 07/2008; 21(7‐8):724 - 730. DOI:10.1002/poc.1382 · 1.23 Impact Factor
  • Addy Pross, Leo Radom
    Progress in Physical Organic Chemistry, Volume 13, 04/2007: pages 1 - 61; , ISBN: 9780470171929
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    Addy Pross
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    ABSTRACT: The physico-chemical characterization of a teleonomic event and the nature of the physico-chemical process by which teleonomic systems could emerge from non-teleonomic systems are addressed in this paper. It is proposed that teleonomic events are those whose primary directive is discerned to be non-thermodynamic, while regular (non-teleonomic) events are those whose primary directive is the traditional thermodynamic one. For the archetypal teleonomic event, cell multiplication, the non-thermodynamic directive can be identified as being a kinetic directive. It is concluded, therefore, that the process of emergence, whereby non-teleonomic replicating chemical systems were transformed into teleonomic ones, involved a switch in the primacy of thermodynamic and kinetic directives. It is proposed that the step where that transformation took place was the one in which some pre-metabolic replicating system acquired an energy-gathering capability, thereby becoming metabolic. Such a transformation was itself kinetically directed given that metabolic replicators tend to be kinetically more stable than non-metabolic ones. The analysis builds on our previous work that considers living systems to be a kinetic state of matter as opposed to the traditional thermodynamic states that dominate the inanimate world.
    Origins of Life and Evolution of Biospheres 09/2005; 35(4):383-94. DOI:10.1007/s11084-005-2045-9 · 1.77 Impact Factor
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    Addy Pross
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    ABSTRACT: A kinetic model that attempts to further clarify the nature of biological complexification is presented. Its essence: reactions of replicating systems and those of regular chemical systems follow different selection rules leading to different patterns of chemical behavior. For regular chemical systems selection is fundamentally thermodynamic, whereas for replicating chemical systems selection is effectively kinetic. Building on an extension of the kinetic stability, concept it is shown that complex replicators tend to be kinetically more stable than simple ones, leading to an on-going process of kinetically-directed complexification. The high kinetic stability of simple replicating assemblies such as phages, compared to the low kinetic stability of the assembly components, illustrates the complexification principle. The analysis suggests that living systems constitute a kinetic state of matter, as opposed to the traditional thermodynamic states that dominate the inanimate world, and reaffirms our view that life is a particular manifestation of replicative chemistry.
    Origins of Life and Evolution of Biospheres 05/2005; 35(2):151-66. DOI:10.1007/s11084-005-5272-1 · 1.77 Impact Factor
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    Addy Pross
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    ABSTRACT: Despite the considerable advances in our understanding of biological processes, the physicochemical relationship between living and nonliving systems remains uncertain and a continuing source of controversy. In this review, we describe a kinetic model based on the concept of dynamic kinetic stability that attempts to incorporate living systems within a con- ventional physicochemical framework. Its essence: all replicating systems, both animate and inanimate, represent elements of a replicator space. However, in contrast to the world of non- replicating systems (all inanimate), where selection is fundamentally thermodynamic, selec- tion within replicator space is effectively kinetic. As a consequence, the nature of stability within the two spaces is of a distinctly different kind, which, in turn, leads to different physicochemical patterns of aggregation. Our kinetic approach suggests: (a) that all living systems may be thought of as manifesting a kinetic state of matter (as apposed to the tradi- tional thermodynamic states associated with inanimate systems), and (b) that key Darwinian concepts, such as fitness and natural selection, are particular expressions of more funda- mental physicochemical concepts, such as kinetic stability and kinetic selection. The ap- proach appears to provide an improved basis for understanding the physicochemical process of complexification by which life on earth emerged, as well as a means of relating life's defining characteristics—its extraordinary complexity, its far-from-equilibrium character, and its purposeful (teleonomic) nature—to the nature of that process of complexification.
    Pure and Applied Chemistry 01/2005; 77(11):1905-1921. DOI:10.1351/pac200577111905 · 3.11 Impact Factor
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    Addy Pross
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    ABSTRACT: The conceptual gulf that separates the 'metabolism first' and 'replication first' mechanisms for the emergence of life continues to cloud the origin of life debate. In the present paper we analyze this aspect of the origin of life problem and offer arguments in favor of the 'replication first' school. Utilizing Wicken's two-tier approach to causation we argue that a causal connection between replication and metabolism can only be demonstrated if replication would have preceded metabolism. In conjunction with existing empirical evidence and theoretical reasoning, our analysis concludes that there is no substantive evidence for a 'metabolism first' mechanism for life's emergence, while a coherent case can be made for the 'replication first' group of mechanisms. The analysis reaffirms our conviction that life is an extreme expression of kinetic control, and that the emergence of metabolic pathways can be understood by considering life as a manifestation of 'replicative chemistry'.
    Origins of Life and Evolution of Biospheres 07/2004; 34(3):307-21. DOI:10.1023/B:ORIG.0000016446.51012.bc · 1.77 Impact Factor
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    Addy Pross, Vladimir Khodorkovsky
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    ABSTRACT: The physico-chemical relationship between living and non-living systems remains a question of intense debate. This paper introduces the concept of dynamic kinetic stability as a means of incorporating living systems within a conventional physico-chemical framework. Its essence, all replicating systems, both animate and inanimate, represent elements of a replicator space. In contrast to the world of non-replicating systems (all inanimate), where selection is fundamentally thermodynamic, selection within replicator space is effectively kinetic. Driven by mutagenic autocatalysis selection in replicator space leads from kinetically less stable systems to kinetically more stable systems. Our kinetic approach suggests that all living systems may be thought of as manifesting a kinetic state of matter (as opposed to the traditional thermodynamic states), and allows the translation of key Darwinian concepts, such as fitness and natural selection, into traditional physico-chemical terms that are applicable at the molecular level. Copyright © 2004 John Wiley & Sons, Ltd.
    Journal of Physical Organic Chemistry 04/2004; 17(4):312 - 316. DOI:10.1002/poc.729 · 1.23 Impact Factor
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    ABSTRACT: [structure: see text] High level ab initio molecular orbital calculations confirm experimental indications that the effect of alkyl substituents (R = Me, Et, i-Pr, t-Bu) on R-X bond dissociation energies varies considerably according to the nature of X. A simple qualitative explanation in terms of valence-bond theory is presented, highlighting the increasing importance of the stabilization of R-X by the ionic R(+)X(-) configuration for electronegative X substituents (such as F, OH, and OCH(3)).
    Organic Letters 12/2003; 5(24):4689-92. DOI:10.1021/ol035860+ · 6.32 Impact Factor
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    Addy Pross
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    ABSTRACT: The principles that govern the emergence of life from non-life remain a subject of intense debate. The evolutionary paradigm built up over the last 50 years, that argues that the evolutionary driving force is the Second Law of Thermodynamics, continues to be promoted by some, while severely criticized by others. If the thermodynamic drive toward ever-increasing entropy is not what drives the evolutionary process, then what does? In this paper, we analyse this long-standing question by building on Eigen's "replication first" model for life's emergence, and propose an alternative theoretical framework for understanding life's evolutionary driving force. Its essence is that life is a kinetic phenomenon that derives from the kinetic consequences of autocatalysis operating on specific biopolymeric systems, and this is demonstrably true at all stages of life's evolution--from primal to advanced life forms. Life's unique characteristics--its complexity, energy-gathering metabolic systems, teleonomic character, as well as its abundance and diversity, derive directly from the proposition that from a chemical perspective the replication reaction is an extreme expression of kinetic control, one in which thermodynamic requirements have evolved to play a supporting, rather than a directing, role. The analysis leads us to propose a new sub-division within chemistry--replicative chemistry. A striking consequence of this kinetic approach is that Darwin's principle of natural selection: that living things replicate, and therefore evolve, may be phrased more generally: that certain replicating things can evolve, and may therefore become living. This more general formulation appears to provide a simple conceptual link between animate and inanimate matter.
    Journal of Theoretical Biology 03/2003; 220(3):393-406. DOI:10.1006/jtbi.2003.3178 · 2.30 Impact Factor
  • Ming Wah Wong, Addy Pross, Leo Radom
    Journal of the American Chemical Society 04/2002; 115(23). DOI:10.1021/ja00076a097 · 11.44 Impact Factor
  • Journal of the American Chemical Society 04/2002; 117(35). DOI:10.1021/ja00140a018 · 11.44 Impact Factor

Publication Stats

2k Citations
307.68 Total Impact Points

Institutions

  • 1995–2013
    • Ben-Gurion University of the Negev
      • Department of Chemistry
      Be'er Sheva`, Southern District, Israel
  • 2002
    • Hebrew University of Jerusalem
      Yerushalayim, Jerusalem, Israel
    • University of North Carolina at Chapel Hill
      North Carolina, United States
    • University of Waterloo
      Ватерлоо, Ontario, Canada
    • University of California, Irvine
      • Department of Chemistry
      Irvine, California, United States
    • University of Queensland
      Brisbane, Queensland, Australia
  • 1995–2002
    • University of Sydney
      • School of Chemistry
      Sydney, New South Wales, Australia
  • 1981–2002
    • Australian National University
      • Research School of Chemistry
      Canberra, Australian Capital Territory, Australia