Hierarchical organization of noise generates spontaneous signal in Paramecium cell

Multiscalar electrical spiking in Schizophyllum commune

Growing colonies of the split-gill fungus Schizophyllum commune show action potential-like spikes of extracellular electrical potential. We analysed several days of electrical activity recording of the fungus and discovered three families of oscillatory patterns. Very slow activity at a scale of hours, slow activity at a scale of 10 min and very fast activity at scale of half-minute. We simulated the spiking behaviour using FitzHugh-Nagume model, uncovered mechanisms of spike shaping. We speculated that spikes of electrical potential might be associated with transportation of nutrients and metabolites.

Language of fungi derived from their electrical spiking activity

Fungi exhibit oscillations of extracellular electrical potential recorded via differential electrodes inserted into a substrate colonized by mycelium or directly into sporocarps. We analysed electrical activity of ghost fungi (Omphalotus nidiformis), Enoki fungi (Flammulina velutipes), split gill fungi (Schizophyllum commune) and caterpillar fungi (Cordyceps militaris). The spiking characteristics are species specific: a spike duration varies from 1 to 21 h and an amplitude from 0.03 to 2.1 mV. We found that spikes are often clustered into trains. Assuming that spikes of electrical activity are used by fungi to communicate and process information in mycelium networks, we group spikes into words and provide a linguistic and information complexity analysis of the fungal spiking activity. We demonstrate that distributions of fungal word lengths match that of human languages. We also construct algorithmic and Liz-Zempel complexity hierarchies of fungal sentences and show that species S. commune generate the most complex sentences.

A design principle for posttranslational chaotic oscillators

Chaos behavior has been observed in various cellular and molecular processes. Here, we modeled reversible phosphorylation dynamics to elucidate a design principle for autonomous chaos generation that may arise from generic enzymatic reactions. A comprehensive parameter search demonstrated that the reaction system composed of a set of kinases and phosphatases and two substrates with two modification sites exhibits chaos behavior. All reactions are described according to the Michaelis-Menten reaction scheme without exotic functions being applied to enzymes and substrates. Clustering analysis of parameter sets that can generate chaos behavior revealed the existence of motif structures. These chaos motifs allow the two-substrate species to interact via enzyme availability and constrain the two substrates' dynamic changes in phosphorylation status so that they occur at different timescales. This chaos motif structure is found in several enzymatic reactions, suggesting that chaos behavior may underlie cellular autonomy in a variety of biochemical systems.

•

Two substrates with reversible two-site phosphorylation can exhibit chaos behavior

•

The chaos does not require autocatalysis or allosteric regulation of enzymes

•

The chaos is a result of the coupling of two substrates via enzyme availability