Biology subjects

Ozkan-Aydin, Y.

Publications and source records attributed to Ozkan-Aydin, Y..

3 recordsLinked to original sources

bioRxiv2021

Emergent collective locomotion in an active polymer model of entangled worm blobs

Numerous worm and arthropod species form physically-connected aggregations in which interactions among individuals give rise to emergent macroscale dynamics and functionalities that enhance collective survival. In particular, some aquatic worms such as the California blackworm (Lumbriculus variegatus) entangle their bodies into dense blobs to shield themselves against external stressors and preserve moisture in dry conditions. Motivated by recent experiments revealing emergent locomotion in blackworm blobs, we investigate the collective worm dynamics by modeling each worm as a self-propelled Brownian polymer. Though our model is two-dimensional, compared to real three-dimensional worm blobs, we demonstrate how a simulated blob can collectively traverse temperature gradients via the coupling between the active motion and the environment. By performing a systematic parameter sweep over the strength of attractive forces between worms, and the magnitude of their directed self-propulsion, we obtain a rich phase diagram which reveals that effective collective locomotion emerges as a result of finely balancing a tradeoff between these two parameters. Our model brings the physics of active filaments into a new meso- and macroscale context and invites further theoretical investigation into the collective behavior of long, slender, semi-flexible organisms.

biophysics↗

bioRxiv2021

Lateral Undulation Aids Biological and Robotic Earthworm Anchoring and Locomotion

Earthworms (Lumbricus terrestris) are characterized by soft, highly flexible and extensible bodies, and are capable of locomoting in most terrestrial environments. Previous studies of earthworm movement have focused on the use of retrograde peristaltic gaits in which controlled contraction of longitudinal and circular muscles results in waves of shortening/thickening and thinning/lengthening of the hydrostatic skeleton. These waves can propel the animal across ground as well as into soil. However, worms can also benefit from axial body bends during locomotion. Such lateral undulation dynamics can aid locomotor function via hooking/anchoring (to provide propulsion), modify travel orientation (to avoid obstacles and generate turns) and even generate snake-like undulatory locomotion in environments where peristaltic locomotion results in poor performance. To the best of our knowledge, the important aspects of locomotion associated with the lateral undulation of an earthworm body are yet to be systematically investigated. In this study, we observed that within confined environments, the worm uses lateral undulation to anchor its body to the walls of their burrows and tip (nose) bending to search the environment. This relatively simple locomotion strategy drastically improved the performance of our soft bodied robophysical model of the earthworm both in a confined (in an acrylic tube) and above-ground heterogeneous environment (rigid pegs), where the peristaltic gait often fails. In summary, lateral undulation facilitates the mobility of earthworm locomotion in diverse environments and can play an important role in the creation of low cost soft robotic devices capable of traversing a variety of environments.

animal behavior and cognition↗

bioRxiv2020

Mechanism and function of root circumnutation

AbstractEarly root growth is critical for plant establishment and survival. We have identified a molecular pathway required for oscillatory root tip movement known as circumnutation. Here we report a multiscale investigation of the regulation and function of this phenomenon. We identify key cell signaling events comprising interaction of the ethylene, cytokinin, and auxin hormone signaling pathways. We identify the gene Oryza sativa Histidine Kinase-1/OsHK1, as well as the auxin influx carrier gene OsAUX1, as essential regulators of this process in rice. Robophysical modelling demonstrated the benefits of tip movement for navigating past obstacles, prompting us to challenge mutant and wild-type plants with different substrates. Consistent with model behavior, root circumnutation facilitated exploration of a solid surface and promoted seedling establishment in rocky soil. Thus, the integration of robotics, physics and biology elucidated the functional importance of root circumnutation and uncovered the molecular mechanisms underlying its regulation. One sentence summaryCircumnutation facilitates root exploration.

plant biology↗