Biology subjects

Dabiri, J. O.

Publications and source records attributed to Dabiri, J. O..

4 recordsLinked to original sources

bioRxiv2025

Non-invasive measurement of metabolic rates of free-swimming jellyfish using volumetric laser scanning

Measuring energy consumption of marine organisms often requires enclosing the animal in a sealed chamber of similar volume to quantify changes in oxygen concentration of the surrounding water. This method limits measurements of free-swimming organisms without boundary effects or movement restrictions. We present energy consumption measurements of free-swimming jellyfish based on 3D morphological reconstructions of the animal during the process of catabolysis utilizing a non-invasive technique. We used a 6-meter tall, 13,600 liter water tank for swimming experiments without food present in the water column. To study continuous swimming, we implemented an onboard microelectronic swim controller that externally stimulated jellyfish swimming for 50 hours. Computer vision-based feedback control was used to enable continuous swimming against a flow current without encountering the vertical limits of the tank over a distance of 2.55 km or 15,000 body lengths. Using a 3D laser scanning system, we created morphological reconstructions of the jellyfish before, during, and after swimming experiments. Changes in animal volume were converted to energy consumption using the body chemical composition determined with elemental analysis. Free-swimming, electrically stimulated animals were found to consume 2.5 times more energy than similarly stimulated animals in a constrained environment, likely due in part to additional hydrodynamic drag associated with free-swimming. Simplified drag models could not fully account for the increased energy consumption. This highlights the need for hydrodynamic models that more effectively capture these dynamics. These measurements suggest that this technique could be applied more broadly to measuring free-swimming metabolic rates of other gelatinous invertebrates. SUMMARY STATEMENTThis article presents measurements of the energy consumption of free-swimming jellyfish by converting changes in animal volume to metabolic rates using a non-invasive laser-scanning technique.

physiology↗

bioRxiv2020

A conserved strategy for inducing appendage regeneration

Can limb regeneration be induced? Few have pursued this question, and an evolutionarily conserved strategy has yet to emerge. This study reports a strategy for inducing regenerative response in appendages, which works across three species that span the animal phylogeny. In Cnidaria, the frequency of appendage regeneration in the moon jellyfish Aurelia was increased by feeding with the amino acid L-leucine and the growth hormone insulin. In insects, the same strategy induced tibia regeneration in adult Drosophila. Finally, in mammals, L-leucine and sucrose administration induced digit regeneration in adult mice, including dramatically from mid-phalangeal amputation. The conserved effect of L-leucine and insulin/sugar suggests a key role for energetic parameters in regeneration induction. The simplicity by which nutrient supplementation can induce appendage regeneration provides a testable hypothesis across animals.

evolutionary biology↗

bioRxiv2020

Field testing of biohybrid robotic jellyfish to demonstrate enhanced swimming speeds

Biohybrid robotic designs incorporating live animals and self-contained microelectronic systems can leverage the animals own metabolism to reduce power constraints and act as natural chassis and actuators with damage tolerance. Previous work established that biohybrid robotic jellyfish can exhibit enhanced speeds up to 2.8 times their baseline behavior in laboratory environments. However, it remains unknown if the results could be applied in natural, dynamic ocean environments and what factors can contribute to large animal variability. Deploying this system in the coastal waters of Massachusetts, we validate and extend prior laboratory work by demonstrating increases in jellyfish swimming speeds up to 2.3 times greater than their baseline, with absolute swimming speeds up to 6.6 {+/-} 0.3 cm s-1. These experimental swimming speeds are predicted using a hydrodynamic model with morphological and time-dependent input parameters obtained from field experiment videos. The theoretical model can provide a basis to choose specific jellyfish with desirable traits to maximize enhancements from robotic manipulation. With future work to increase maneuverability and incorporate sensors, biohybrid robotic jellyfish can potentially be used track environmental changes in applications for ocean monitoring.

bioengineering↗

bioRxiv2019

Primitive and modern swimmers solve the challenges of turning similarly to achieve high maneuverability

Animal swimmers alter trajectories - or turn - for a variety of critical life functions such as feeding, mating and avoiding predation. Yet turning represents a fundamental dilemma based in rotational dynamics: the torque powering a turn is favored by an expanded body configuration, yet minimizing the resistance to a turn (the moment of inertia) is favored by a contracted body configuration. How do animals balance these opposing demands to achieve high maneuverability? By noninvasively measuring fluid and body motions, we found that both jellyfish (Aurelia aurita) and fish (Danio rerio) initially maximized torque using previously undescribed, rapid body movements. Both species then minimized resistance to turning by bending their bodies to reduce their moment of inertia. Use of this sequential solution by such distantly related animals as an invertebrate and a vertebrate suggests strong selection for these turning dynamics that may extend to other swimmers and inform future vehicle designs.

zoology↗