The colloidal nature of complex fluids enhances bacterial motility

Nature, Год журнала: 2022, Номер 603(7903), С. 819 - 823

Опубликована: Март 30, 2022

Язык: Английский

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Phototaxis of Chlamydomonas arises from a tuned adaptive photoresponse shared with multicellular Volvocine green algae

Physical review. E, Год журнала: 2023, Номер 107(1)

Опубликована: Янв. 20, 2023

Many microorganisms have the ability to move toward a light source, and authors study this process in Chlamydomonas, unicellular member of family green algae. They show that mechanism is shared with multicellular algae same family, shedding on evolutionary transition from organisms.

Язык: Английский

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Chiral Locomotion Transitions of an Active Gel and Their Chemomechanical Origin

Journal of the American Chemical Society, Год журнала: 2025, Номер unknown

Опубликована: Янв. 28, 2025

Transitions between chiral rotational locomotion modes occur in a variety of active individuals and populations, such as sidewinders, self-propelled droplets, dense bacterial suspensions. Despite recent progress the study matter, general principles governing transition remain elusive. Here, we study, experimentally theoretically, its 2D polyacrylamide (PAAm)-based BZ gel driven by Belousov-Zhabotinsky reaction-diffusion waves. Analysis reveals that phase difference (Δφ) orthogonal components kinematic quantities, chemomechanical force, displacement, velocity, determines chirality, i.e., occurs when Δφ changes sign. This criterion is illustrated with equation, which can be applied to biological physical systems, including super-rotational/superhelical reported recently during E. gracilis swimming sperm navigation. work has potential applications for design functional materials intelligent robots.

Язык: Английский

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Spontaneous phase coordination and fluid pumping in model ciliary carpets

Proceedings of the National Academy of Sciences, Год журнала: 2022, Номер 119(45)

Опубликована: Ноя. 2, 2022

Ciliated tissues, such as in the mammalian lungs, brains, and reproductive tracts, are specialized to pump fluid. They generate flows by collective activity of hundreds thousands individual cilia that beat a striking metachronal wave pattern. Despite progress analyzing coordination, general theory links coordination fluid pumping limit large arrays remains lacking. Here, we conduct silico experiments with hydrodynamically interacting cilia, develop continuum infinitely many independently beating combining tools from active matter classical Stokes flow. We find, both simulations theory, isotropic synchronized ciliary states unstable. Traveling waves emerge regardless initial conditions, but characteristics net depend on tissue properties. That is, phase is stable global attractor carpets, even under finite perturbations These results support notion functional specificity ciliated tissues interlaced architecture kinematics open up prospect establishing structure function maps cilium-level tissue-level pumping.

Язык: Английский

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Phenotyping single-cell motility in microfluidic confinement

eLife, Год журнала: 2022, Номер 11

Опубликована: Ноя. 23, 2022

The movement trajectories of organisms serve as dynamic read-outs their behaviour and physiology. For microorganisms this can be difficult to resolve due small size fast movement. Here, we devise a novel droplet microfluidics assay encapsulate single micron-sized algae inside closed arenas, enabling ultralong high-speed tracking the same cell. Comparing two model species - Chlamydomonas reinhardtii (freshwater, 2 cilia), Pyramimonas octopus (marine, 8 detail highly-stereotyped yet contrasting swimming behaviours environmental interactions. By measuring rates probabilities with which cells transition between trio motility states (smooth-forward swimming, quiescence, tumbling or excitable backward swimming), reconstruct control network that underlies gait switching dynamics. A simplified cell-roaming in circular confinement reproduces observed long-term spatial fluxes, including boundary circulation behaviour. Finally, establish an pairs droplets are fused on demand, one containing trapped cell another chemical perturbs cellular excitability, reveal how aneural adapt locomotor patterns real-time.

Язык: Английский

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Jeffery’s Orbits and Microswimmers in Flows: A Theoretical Review

Journal of the Physical Society of Japan, Год журнала: 2023, Номер 92(6)

Опубликована: Май 17, 2023

In this review, we provide a theoretical introduction to Jeffery's equations for the orientation dynamics of an axisymmetric object in flow at low Reynolds number, and review recent extensions applications motions self-propelled particles, so-called microswimmers, external flows. Bacteria colonize human organs medical devices even with flowing fluid, microalgae occasionally cause huge harmful toxic blooms lakes oceans, artificial microrobots can migrate flows generated well-designed microfluidic chambers. The Jeffery equations, simple set ordinary differential equation, useful building block modeling, analyzing, understanding these microswimmer current, particular when incorporating impact swimmer shape since contain parameter as single scalar, known Bretherton parameter. particle forms closed orbit situated shear, non-uniform periodic rotational motion, referred orbits, is due constant motion non-linear equation. After providing hydrodynamics derivation discuss possible more general shapes, including those rapid deformation. latter part mathematical models microswimmers different types fields are described, focus on constants their relation phase space, together breakdown degenerate stable, unstable, chaotic system. discussion paper will comprehensive foundation orbits be understand under various

Язык: Английский

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Multiflagellate Swimming Controlled by Hydrodynamic Interactions

Physical Review Letters, Год журнала: 2024, Номер 132(20)

Опубликована: Май 16, 2024

Many eukaryotic microorganisms propelled by multiple flagella can swim very rapidly with distinct gaits. Here, we model a three-dimensional mutiflagellate swimmer, resembling the microalgae. When are actuated synchronously, swimming efficiency be enhanced or reduced interflagella hydrodynamic interactions (HIs), determined intrinsic tilting angle of flagella. The asynchronous gait phase difference between neighboring reduce oscillatory motion via basal mechanical coupling. In presence spherical body, simulations taking into account flagella-body reveal advantage anterior configuration compared posterior configuration, where in latter case an optimal number arises. Apart from understanding role HIs multiflagellate microorganisms, this work could also guide laboratory fabrications novel microswimmers.

Язык: Английский

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Reinforcement learning selects multimodal locomotion strategies for bioinspired microswimmers

Soft Matter, Год журнала: 2025, Номер unknown

Опубликована: Янв. 1, 2025

Natural microswimmers exhibit multimodal locomotion strategies to achieve versatile navigation tasks such as finding nutrient sources, avoiding danger and migrating new habitats. These typically involve complex coordination of cell actuators (i.e., flagella) generate translation, rotation combined motions. Yet, it is generally difficult establish a simple relationship between actuation due the hydrodynamic coupling swimmer surrounding fluid. While many bioinspired have been engendered, remains challenging for these artificial swimmers effective different functional similar their biological counterparts. Here, we explore reinforcement learning (RL) method enable microswimmer select based on tasks. We illustrate this approach using model derived from Chlamydomonas reinhardtii, which consists body sphere two flagella spheres. first demonstrate that RL-powered can maximize displacement or minimize energy input by setting corresponding goals. further how RL multi-directional via coordinately switch forward steering gaits. Our opens avenue designing with capabilities.

Язык: Английский

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Twist–torsion coupling in beating axonemes

Nature Physics, Год журнала: 2025, Номер unknown

Опубликована: Фев. 24, 2025

Язык: Английский

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Three-dimensional tracking of microswimmer suspensions

Experiments in Fluids, Год журнала: 2025, Номер 66(4)

Опубликована: Март 28, 2025

Abstract Understanding the locomotion of microorganisms is essential for insights into microbial ecology, infection, and colonization processes. Although two-dimensional microscopy has been widely used to study microswimmer motility, it does not capture full extent their three-dimensional (3D) movement. Recent advances in defocused particle tracking, holographic tracking velocimetry, stereo-microscopy face challenges achieving high resolution at larger densities multiple microswimmers suspension. In this work, we introduce a novel multi-camera system that significantly improves accuracy 3D tracking. Our uses four sCMOS cameras image within 2.5 $$\times$$ × 2 mm $$^3$$ 3 . We assess performance our by population unicellular motile algae Chlamydomonas reinhardtii An in-house algorithm based on projective geometry framework enables with reprojection errors below 0.3 body lengths. This supports imaging source 0.32, higher than other existing single camera techniques. Analysis C. trajectories reveals predominance left-handed chirality helical swimming patterns. Moreover, data provide translational rotational diffusion coefficients differ from those obtained using traditional methods.

Язык: Английский

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