La thèse aborde différentes questions de chimie prébiotique dans le contexte de l’origine de la vie par une approche de chimie systémique. La première partie est dédiée à l’étude de processus d’activation chimique important non seulement pour la formation de polymères, mais aussi pour alimenter le système en énergie de manière à le maintenir dans un état éloigné de l’équilibre, un prérequis pour l’auto-organisation. Il a été suggéré que les intermédiaires 5(4H)-oxazolones formés par l’activation de l’extrémité C-terminale des peptides pourrait être impliquée dans l’auto-organisation du vivant. Dans ce but, nous avons évalué la réactivité de réactifs pertinents dans un contexte prébiotique et décrits dans la littérature comme capables d’activer des acides α-aminés. Aucun d’entre eux n’a manifesté une activité satisfaisante pour l’activation C-terminale des peptides, montrant qu’une voie possible pour alimenter un protométabolisme des peptides en énergie n’est pas identifiée à ce jour à l’exception notable des N-carboxyanhydrides (NCA) qui peuvent être formé par des voies prébiotiquement plausibles. Nous avons par ailleurs démontré que les carbodiimides sont aussi efficaces pour l’activation des N-carbamoylamino acides que pour celle du carboxyle terminal des peptides en milieu aqueux dilué. La seconde partie du document expose de nouveaux résultats en faveur d’un processus de coévolution peptides-nucléotides. D’abord, une étude de la réactivité d’agents d’aminoacylation de l’extrémité 3’ de l’ARN est présentée. Ensuite, nous évaluons des co-polymères acides α-aminés-nucléotides liés par des enchaînements phosphoramidate et esters comme partenaires éventuels de l’évolution chimique. La pertinence cinétique de ces structures est démontrée ainsi que des voies chimiques permettant leur formation. / The thesis addresses several issues in prebiotic chemistry in the context of the origins of life through a systems chemistry approach. The first part is devoted to the study of chemical activation processes that are not only important in the formation of polymers, but also to feed the system with energy in order that a far from equilibrium state is maintained, a prerequisite for self-organization. It has been suggested that 5(4H)-oxazolones intermediates formed by C-terminus peptide activation could be involved in self-organization of life. To this aim, we have checked the reactivity of relevant prebiotic reagents previously proposed to activate α-amino acids. None of them led to a satisfactory C-terminus activation of peptides, showing that no general process for feeding a protometabolism of peptides with energy is identified yet, with the notable exception of N-carboxyanhydrides (NCAs) that can be formed through prebiotically relevant pathways. Additionally, we demonstrated that carbodiimides reagents are as efficient in the activation of N-carbamoyl amino acids as in that of the C-terminus of peptides in diluted aqueous media. The second part of the dissertation discloses new results in support of a process of coevolution of peptides and nucleotides. Firstly, a study of non-enzymatic aminoacylation reagents of the 3’-terminus of RNA is presented. Secondly, we assessed co-polymers of α-amino acids and nucleotides bound by phosphoramidate and ester linkages as potential players in chemical evolution. The kinetic relevance of these structures was demonstrated as well as potential chemical processes that allow their formation.

A presente tese se desenvolve por meio da constituição do conceito de protoforma orgânica com o qual objetivamos tratar de relações problemáticas entre as noções gerais de vida e individualidade, particularmente no que se refere ao problema de suas origens, compreendida aqui como o momento privilegiado da gênese organo-vital no qual a tensão entre vida e individualidade se expressa de modo mais evidente. Vida, individualidade e origens se constituem em noções gerais e em grandes temas da investigação e da reflexão filosófica e científica de todos os tempos. O conceito de protoforma orgânica emerge da observação de diversos elementos em um solo histórico-conceitual de investigações científicas e em filosofia natural, que se constitui num conjunto de expressões históricas particulares que investigamos em nossa tese, a saber, os conceitos de monera, de Urschleim e de Urpflanze. Estruturamos o conceito de protoforma orgânica a partir de duas noções-eixo que nortearam o seu sentido. A primeira delas é a noção de uma polaridade entre uma condição pré-individual e uma condição individual como constituinte da forma orgânica. A segunda é a noção de memória orgânica como uma propriedade anímico-psíquica das formas orgânicas universalmente presente, desde os seus níveis mais elementares. Trata-se, assim, de compreender como se dá a relação problemática entre vida e individualidade e como a questão das suas origens pode contribuir para tal compreensão. Assim, o conceito de protoforma orgânica foi estruturado dentro de uma visão morfológica na qual as noções de forma e de orgânico se entrelaçam com as noções de vida e de individualidade. / The present thesis proposes the constitution of the concept of organic protoform with which we aim to deal with problematic relations between the general notions of life and individuality. Particularly with regard to the problem of its origins, understood here as the privileged moment of the genesis of organo-vital beings, at which moment the tension between life and individuality is expressed more clearly. Life, individuality and origins are general notions and themes of research and philosophical and scientific reflection of all time. The concept of organic protoform emerges from the observation of several elements directed to a historical-conceptual soil of scientific investigations and natural philosophy. This basis is constituted by our investigation into a set of particular historical expressions which we investigate in our thesis, namely the concepts of monera, Urschleim and Urpflanze. We structured the concept of organic protoform from two notions-axis that guided its meaning. The first is the notion of a polarity between a preindividual condition and an individual condition as a constituent of the organic form. The second is the notion of organic memory as a psychic property of organic forms universally present, from its most elementary levels. It is therefore a question of understanding how the problematic relationship between life and individuality takes place and how the question of its origins can contribute to this understanding. Thus, the concept of organic protoform was structured within a morphological vision in which the notions of form and of organic intertwine with the notions of life and of individuality.

A presente tese se desenvolve por meio da constituição do conceito de protoforma orgânica com o qual objetivamos tratar de relações problemáticas entre as noções gerais de vida e individualidade, particularmente no que se refere ao problema de suas origens, compreendida aqui como o momento privilegiado da gênese organo-vital no qual a tensão entre vida e individualidade se expressa de modo mais evidente. Vida, individualidade e origens se constituem em noções gerais e em grandes temas da investigação e da reflexão filosófica e científica de todos os tempos. O conceito de protoforma orgânica emerge da observação de diversos elementos em um solo histórico-conceitual de investigações científicas e em filosofia natural, que se constitui num conjunto de expressões históricas particulares que investigamos em nossa tese, a saber, os conceitos de monera, de Urschleim e de Urpflanze. Estruturamos o conceito de protoforma orgânica a partir de duas noções-eixo que nortearam o seu sentido. A primeira delas é a noção de uma polaridade entre uma condição pré-individual e uma condição individual como constituinte da forma orgânica. A segunda é a noção de memória orgânica como uma propriedade anímico-psíquica das formas orgânicas universalmente presente, desde os seus níveis mais elementares. Trata-se, assim, de compreender como se dá a relação problemática entre vida e individualidade e como a questão das suas origens pode contribuir para tal compreensão. Assim, o conceito de protoforma orgânica foi estruturado dentro de uma visão morfológica na qual as noções de forma e de orgânico se entrelaçam com as noções de vida e de individualidade. / The present thesis proposes the constitution of the concept of organic protoform with which we aim to deal with problematic relations between the general notions of life and individuality. Particularly with regard to the problem of its origins, understood here as the privileged moment of the genesis of organo-vital beings, at which moment the tension between life and individuality is expressed more clearly. Life, individuality and origins are general notions and themes of research and philosophical and scientific reflection of all time. The concept of organic protoform emerges from the observation of several elements directed to a historical-conceptual soil of scientific investigations and natural philosophy. This basis is constituted by our investigation into a set of particular historical expressions which we investigate in our thesis, namely the concepts of monera, Urschleim and Urpflanze. We structured the concept of organic protoform from two notions-axis that guided its meaning. The first is the notion of a polarity between a preindividual condition and an individual condition as a constituent of the organic form. The second is the notion of organic memory as a psychic property of organic forms universally present, from its most elementary levels. It is therefore a question of understanding how the problematic relationship between life and individuality takes place and how the question of its origins can contribute to this understanding. Thus, the concept of organic protoform was structured within a morphological vision in which the notions of form and of organic intertwine with the notions of life and of individuality.

L’émergence de la complexité, et de la vie en particulier, demeure l’une des énigmes les plus complexes pour la science moderne. Des travaux récents ont souligné la pertinence d’un apport de la physique statistique et de la théorie des phénomènes critiques — et en particulier de la théorie des phénomènes à criticalité auto-régulée — relativement à ces champs d’intérêt, tout autant que du rôle des phénomènes de coopération biochimique dans les premiers instants du vivant. La description des mécanismes par lesquels la vie a pu apparaître est par ailleurs d’un intérêt pratique pour l’astrophysique, puisque notre compréhension de ceux-ci module la manière dont l’analyse de biosignatures s’effectue dans le cadre de la recherche de la vie ailleurs dans l’Univers. L’analyse proposée ici porte sur un modèle en théorie des jeux permettant d’étudier les phénomènes de coopération implémenté dans un contexte spatial servant à émuler la dynamique d’un système ayant pu voir apparaître la vie. Une analyse de l’espace des paramètres du modèle révèle que celui-ci affiche des phénomènes de transition de phase et d’auto-organisation de structures spatiales, ces éléments se révélant des adjuvants à l’émergence de la coopération entre joueurs a priori égoïstes, dans un contexte qui à prime abord n’est pas d’emblée favorable à l’apparition de comportements coopératifs. Les résultats obtenus ici semblent supporter que la coopération biochimique puisse apparaître via un phénomène de transition de phase et que le modèle sous-jacent de dilemme du prisonnier itéré sur réseau présenté ici agit comme un système à criticalité autorégulée. / The emergence of complexity, and of life more specifically, is still one of the most intractable conundrums for modern science. Recent work emphasized the relevance of statistical physics and critical phenomena theory’s contribution to those questions — especially of self-organized criticality theory — just as much as the role of biochemical cooperation in life’s first moments. Moreover, the description of the mechanisms by which life could have appeared is of particular interest for astrophysics, because our comprehension of those mechanisms influences how biosignatures are analyzed in the context of the search for life elsewhere in the Universe. The analysis presented here concerns a model in game theory that allows to study cooperation phenomena — implemented in spatial context as to emulate the dynamics of a system in which life could have appeared. An analysis of the model’s parameter space reveals that it displays phase transition and self-organization of spatial structures phenomenon, those elements being adjuvants to the emergence of cooperation between a priori egoist players, in a context that is initially not favorable to the emergence of cooperative behavior. The results obtained here thus seem to support the idea that both biochemical cooperation can emerge through phase transition phenomena, and that the underlying lattice iterated prisoner’s dilemma model used here behaves like a self-organized critical system.

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