Bridging Nonliving and Living Matter

Abstract

Assembling non-biological materials (geomaterials) into a proto-organism constitutes a bridge between nonliving and living matter. In this article we present a simple step-by-step route to assemble a proto-organism. Many pictures have been proposed to describe this transition within the origins-of-life and artificial life communities, and more recently alternative pictures have been emerging from advances in nanoscience and biotechnology. The proposed proto-organism lends itself to both traditions and defines a new picture based on a simple idea: Given a set of required functionalities, minimize the physicochemical structures that support these functionalities, and make sure that all structures self-assemble and mutually enhance each other's existence. The result is the first concrete, rational design of a simple physicochemical system that integrates the key functionalities in a thermodynamically favorable manner as a lipid aggregate integrates proto-genes and a proto-metabolism. Under external pumping of free energy, the metabolic processes produce the required building blocks, and only specific gene sequences enhance the metabolic kinetics sufficiently for the whole system to survive. We propose an experimental implementation of the proto-organism with a discussion of our experimental results, together with relevant results produced by other experimental groups, and we specify what is still missing experimentally. Identifying the missing steps is just as important as providing the road map for the transition. We derive the kinetic and thermodynamic conditions of each of the proto-organism subsystems together with relevant theoretical and computational results about these subsystems. We present and discuss detailed 3D simulations of the lipid aggregation processes. From the reaction kinetics we derive analytical aggregate size distributions, and derive key properties of the metabolic efficiency and stability. Thermodynamics and kinetics of the ligation directed self-replication of the proto-genes is discussed, and we summarize the full life cycle of the proto-organism by comparing size, replication time, and energy with the biomass efficiency of contemporary unicells. Finally, we also compare our proto-organism picture with existing origins-of-life and protocell pictures. By assembling one possible bridge between nonliving and living matter we hope to provide a piece in the ancient puzzle about who we are and where we come from.

Construction de cellules synthétiques

“…La cellule artificielle consiste à mettre ensemble des molécules naturelles et synthétiques pour concevoir des compartiments microscopiques programmés pour des fonctions spécifiques. En utilisant des éléments artificiels, cette approche a aussi pour objectif d'étendre les propriétés des systèmes naturels [17]. Par exemple, la membrane des polymersomes (compartiment de taille cellulaire dont la membrane est faite de copolymères à blocs 2 ) est beaucoup plus robuste que les bicouches lipidiques naturelles [18][19][20][21].…”

Moral action as cheater suppression in human super organisms: Testing the human superorganism approach to morality

“…[35,56,57] As living systems, they are complex adaptive systems that are open (i.e., exchange material, energy and information with their environments) and self-organizing (by means of interactions among their elements), with emergent properties. Relevant kinds of organizational functions at the superorganism level can therefore be extracted from 'living systems' theory, [58], 'minimal life' theory, [59][60][61] collective animal behaviour, [57] and eusocial insect ecology (where these societies are treated as superorganisms), [42][43][44]62] as well by comparison to the set of organs in multi-cellular organisms like Mammals, and the Indian caste system (taken as an example of a human superorganism) (see Table 1 below). 1 ^ The recently identified endocannabinoid system (composed of a class of lipids and specialized brain receptors) plays a central role in the regulation of learning and memory.…”

Lifeness signatures and the roots of the tree of life

“…Luisi 1998;Ruiz-Mirazo et al 2004). In a similar fashion, one could question whether minimal protoliving systems as those proposed by Szostak, Bartel and Luisi (2001) or Libchaber and his team (Noireaux et al 2005), might more properly qualify as alive than, for instance, those pursued by Rasmussen and colleagues (Rasmussen et al 2003). And so forth.…”