Random network peristalsis in
            <i>Physarum polycephalum</i>
            organizes fluid flows across an individual

Alim, Karen; Amselem, Gabriel; Peaudecerf, François J.; Brenner, Michael P.; Pringle, Anne

doi:10.1073/pnas.1305049110

Cited by 150 publications

(181 citation statements)

References 36 publications

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“…Although the chemical nature of the signaling molecule so far remains unidentified the discovery of the mechanism of signal propagation itself allows us to understand P. polycephalum's complex dynamics. The mechanism implies that the peristaltic wave matches organism size, explaining our previous observation (12). Moreover the mechanism, working in tandem with tube radius adaptation in response to the increased flow, seems sufficient to explain how P. polycephalum is able to solve a maze and build efficient transport networks.…”

Section: Significancesupporting

confidence: 57%

“…Building on our previous observations (12,18), we now report and characterize the mechanism of communication in P. polycephalum and demonstrate that a simple feedback between a signaling molecule and a propagating contraction front is sufficient to explain P. polycephalum's sophisticated behaviors. The key experiment demonstrates that a localized nutrient stimulus…”

mentioning

confidence: 59%

“…Contractions drive periodic cytoplasmic fluid flows, and these extend across an entire individual. Intriguingly, the fluid flows are highly coordinated (12), and the phase of oscillations is tuned such that there is exactly one wavelength across an individual, regardless of an individual's size. Data suggest P. polycephalum is somehow able to measure its size.…”

mentioning

confidence: 99%

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Mechanism of signal propagation in Physarum polycephalum

Alim

Andrew

Pringle

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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Complex behaviors are typically associated with animals, but the capacity to integrate information and function as a coordinated individual is also a ubiquitous but poorly understood feature of organisms such as slime molds and fungi. Plasmodial slime molds grow as networks and use flexible, undifferentiated body plans to forage for food. How an individual communicates across its network remains a puzzle, but Physarum polycephalum has emerged as a novel model used to explore emergent dynamics. Within P. polycephalum, cytoplasm is shuttled in a peristaltic wave driven by cross-sectional contractions of tubes. We first track P. polycephalum's response to a localized nutrient stimulus and observe a front of increased contraction. The front propagates with a velocity comparable to the flow-driven dispersion of particles. We build a mathematical model based on these data and in the aggregate experiments and model identify the mechanism of signal propagation across a body: The nutrient stimulus triggers the release of a signaling molecule. The molecule is advected by fluid flows but simultaneously hijacks flow generation by causing local increases in contraction amplitude as it travels. The molecule is initiating a feedback loop to enable its own movement. This mechanism explains previously puzzling phenomena, including the adaptation of the peristaltic wave to organism size and P. polycephalum's ability to find the shortest route between food sources. A simple feedback seems to give rise to P. polycephalum's complex behaviors, and the same mechanism is likely to function in the thousands of additional species with similar behaviors. acellular slime mold | transport network | behavior | Taylor dispersion O ne of the great challenges of unraveling biological complexity is understanding what kind of and how much computational power is required for an organism to generate sophisticated behaviors. Behaviors are typically associated with a nervous system, but many organisms without nervous systems integrate information and function as coordinated individuals (1); examples range from the ability of Escherichia coli to move up chemical gradients (2) to the ability of a multicellular fungus to sense and precisely explore unoccupied space (3). A recently published and striking example of a complex behavior involves bacteria within a biofilm: When a Bacillus subtilis biofilm is deprived of nutrients, bacteria are able to grow networks of channels and evaporatively pump flows, creating intricate structures that benefit the entire community (4).Perhaps the archetypal example of an apparently simple organism able to generate sophisticated behaviors is the slime mold Physarum polycephalum, whose behaviors are repeatedly characterized as "intelligent." This slime mold is able to navigate mazes by finding the shortest route between different food sources (5) and has used its ability to reconstruct the transportation maps of major cities (6). The organism can structure its connections to different nutrient sources to optimize its diet...

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Section: Significancesupporting

confidence: 57%

mentioning

confidence: 59%

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Mechanism of signal propagation in Physarum polycephalum

Alim

Andrew

Pringle

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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“…10 Research frontiers are also oriented towards hybrid systems, where biological systems are key components of electronic devices. [11][12][13] For example, the adaptive 'learning' behavior of slime mould Physarum polycephalum (PPM) was described in terms of memristor model; 14,15 the mould also resulted to be able to perform complex tasks of the information processing. [16][17][18] Gale et al 19 observed occasionally that PPM protoplasmic tubes showed hysteretic current-voltage characteristics, consistent with those of the memristive systems.…”

Section: Introductionmentioning

confidence: 99%

Polysaccarides-based gels and solid-state electronic devices with memresistive properties: Synergy between polyaniline electrochemistry and biology

et al. 2016

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A multidisciplinary approach to study the functional properties of neuron-like cell models constituting a living bio-hybrid system: SH-SY5Y cells adhering to PANI substrate AIP Advances 6, 111303 (2016) A new architecture of organic memristive device is proposed with a double-layered polyelectrolyte, one of which is a biological system that alone drives the memristive behavior. In the device the Physarum polycephalum was used as living organism, the polyaniline as conducting polymer for the source-drain channel. The key choice for the device functioning was the interposition of a biocompatible solid layer between polyaniline and living organism, that must result both electrochemically inert and able to preserve a good electrical conductivity of the polyaniline, notwithstanding the alkaline pH environment required for the surviving of living being, by avoiding strong acids. Pectin with a high degree of methylation and chitosan were tested as interlayer, but only the first one satisfied the essential requirements. It was demonstrated that only when the living organism was integrated in the device, the current-voltage characteristics showed the hysteretic rectifying trends typical of the memristive devices, which however disappeared if the Physarum polycephalum switched to its sclerotic state. The mould resulted to survive a series of at least three cycles of voltage-current measurements carried out in sequence. © 2016 Author(s)

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“…In this mode of growth, P. polycephalum is actively motile (has been observed moving up to 10 mm per hour) and will search for food sources. In addition, it will also lay down protoplasmic tubes to connect any food sources and re-direct nutrients though the protoplasmic tubes by peristalsis (Alim et al, 2013) to the most active regions of the organism. P. polycephalum has been shown to be sensitive to bright light (Ueda et al, 1988) and specific chemical cues (Costello and Adamatzky, 2013), which have been used to control the direction of plasmodium locomotion.…”

Section: Introductionmentioning

confidence: 99%