Autopoiesis: a review and a reappraisal

Abstract

The aim of the paper is to review critically the notion of autopoiesis as presented by Maturana and Varela. In particular, recognizing that there are difficulties in obtaining a complete and clear picture from the primary literature, an effort is made to present a coherent view-also based on many years of personal contact with Francisco Varela. The paper begins with a few historical notes to highlight the cultural background from which the notion of autopoiesis arose. The basic principles of autopoiesis as a theory of cellular life are then described, emphasizing also what autopoiesis is not: not an abstract theory, not a concept of artificial life, not a theory about the origin of life-but rather a pragmatic blueprint of life based on cellular life. It shown how this view leads to a conceptually clear definition of minimal life and to a logical link with related notions, such as self-organization, emergence, biological autonomy, auto-referentiality, and interactions with the environment. The perturbations brought about by the environment are seen as changes selected and triggered by the inner organization of the living. These selective coupling interactions impart meaning to the minimal life and are thus defined by Maturana and Varela with the arguable term of "cognition". This particular view on the mutual interactions between living organism and environment leads these authors to the notion of "enaction", and to the surprising view that autopoiesis and cognition are two complementary, and in a way equivalent, aspects of life. It is then shown how cognition, so defined, permits us to build a bridge between biology and cognitive science. Autopoiesis also allows one to conceive chemical models of minimal cellular life that can be implemented experimentally. The corresponding work on "chemical autopoiesis" is then reviewed. The surprising impact of autopoiesis in the social sciences ("social autopoiesis") is also briefly discussed. This review also comments on why the theory of autopoiesis had, and still has, a difficult time being accepted into the mainstream of life-science research. Finally, it is pointed out that the new interest in system biology and complexity theories may lead to a reappraisal of autopoiesis and related notions, as outlined also by other authors, such as Tibor Ganti and Stuart Kauffmann. P. L. Luisi ( ) )

Directed Growth of Biomimetic Microcompartments

“…The autopoietic theory was also centered on the membrane but focused on self-maintenance rather than on (self-)reproduction. [3,4] However, such a self-maintaining system could also enter a self-reproduction mode, manifested by growth, if homeostatic misbalance leads to excess membrane formation as shown in a thought experiment by Luisi. [3] In this progress report, we review the existing approaches for growth of compartments in the context of bottom-up synthetic biology and protobiology.…”

“…[3,4] However, such a self-maintaining system could also enter a self-reproduction mode, manifested by growth, if homeostatic misbalance leads to excess membrane formation as shown in a thought experiment by Luisi. [3] In this progress report, we review the existing approaches for growth of compartments in the context of bottom-up synthetic biology and protobiology. We consider mainly micrometer-sized compartments due to their characteristic cellular dimensions; this feature also ensures that the area and curvature of the interface or the bounding membrane has less influence on the enclosed solution.…”

Autopoietic Behavior of Dynamic Covalent Amphiphiles

“…[34] The minimal criteria defining autopoiesis should verify whether 1) the system has a semipermeable boundary that is 2) produced within the system and 3) that encompasses reactions that regenerate the components of the system. [35] Minimal autopoietic systems were then chemically designed in micellar and vesicular systems by Luisi et al,w ho described the autocatalysist aking place in the nonreversible formation of some surfactant molecules. [36,37] In our originally discussed case of dynamic surfactants, [33] a biphasic environment was observed at the early stage of the autocatalytic formation of micelles owing to emulsions of the hydrophobic aldehyde, ap henomenont hat could also participate in the complexity of the system.…”

Spontaneous chiral symmetry breaking in early molecular networks

“…Many such treatises assume that chiral selection has occurred under abiotic conditions, and preceded (or even served as a prerequisite for) life's origin. Among these are models that involve bifurcation in small molecules [8-10] In parallel, systems were reported that involve polymerization [11,12] as well as interactions within crystals (reviewed in [12]). The basic principles that guide such papers include the notion of statistical fluctuations, namely that in an ensemble of asymmetric molecules of a given type, there will always be an excess of one enantiomer, particularly apparent in small ensembles, and that such fortuitous excess may be greatly amplified by catalytic or replicative reactions [8].…”

“…Life is believed to have emerged by self organization processes occurring within a random and highly heterogeneous chemical environment [10,13]. One of the hallmarks of some other prebiotic evolution studies is the assumption that homochirality (the prevalence of only one of the two chiral isomers), widespread in present-day life, has emerged as part of the processes that led to cellular life [14-19].…”