Both physiological and evolutionary criteria of biological individuality are underpinned by the idea that an individual is a functionally integrated whole. However, a precise account of functional integration has not been provided so far, and current notions are not developed in the details, especially in the case of composite systems. To address this issue, this paper focuses on the organisational dimension of two representative associations of prokaryotes: biofilms and the endosymbiosis between prokaryotes. Some critical voices have been raised against the (...) thesis that biofilms are biological individuals. Nevertheless, it has not been investigated which structural and functional obstacles may prevent them from being fully integrated physiological or evolutionary units. By contrast, the endosymbiotic association of different species of prokaryotes has the potential for achieving a different type of physiological integration based on a common boundary and interlocked functions. This type of association had made it possible, under specific conditions, to evolve endosymbionts into fully integrated organelles. This paper therefore has three aims: first, to analyse the organisational conditions and the physiological mechanisms that enable integration in prokaryotic associations; second, to discuss the organisational differences between biofilms and prokaryotic endosymbiosis and the types of integration they achieve; finally, to provide a more precise account of functional integration based on these case studies. (shrink)

Although the analogy between macroscopic machines and biological molecular devices plays an important role in the conceptual framework of both neo-mechanistic accounts and nanotechnology, it has recently been claimed that certain complex molecular devices cannot be considered machines since they are subject to physicochemical forces that are different from those of macroscopic machines. However, the structural and physicochemical conditions that allow both macroscopic machines and microscopic devices to work and perform new functions, through a combination of elemental functional parts, have (...) not yet been examined. In order to fill this void, this paper has a threefold aim: first, to clarify the structural and organisational conditions of macroscopic machines and microscopic devices; second, to determine whether the machine-like analogy fits nanoscale devices; and third, to assess whether the machine-like analogy is appropriate for describing the behaviour of some biological macromolecules. Finally, the paper gives an account of ‘machine’ which, while acknowledging the physicochemical and organisational differences between man-made machines and biological microscopic devices, nevertheless identifies a common conceptual core that allows us to consider the latter ‘machines’. (shrink)

Organoids and organs-on-a-chip are currently the two major families of 3D advanced organotypic in vitro culture systems, aimed at reconstituting miniaturized models of physiological and pathological states of human organs. Both share the tenets of the so-called “three-dimensional thinking”, a Systems Physiology approach focused on recapitulating the dynamic interactions between cells and their microenvironment. We first review the arguments underlying the “paradigm shift” toward three-dimensional thinking in the in vitro culture community. Then, through a historically informed account of the technical (...) affordances and the epistemic commitments of these two approaches, we highlight how they embody two distinct experimental cultures. We finally argue that the current systematic effort for their integration requires not only innovative “synergistic” engineering solutions, but also conceptual integration between different perspectives on biological causality. (shrink)

Compte rendu de Quentin Hiernaux, Du comportement végétal à l’intelligence des plantes?