Biology subjects

Van Wassenbergh, S.

Publications and source records attributed to Van Wassenbergh, S..

3 recordsLinked to original sources

bioRxiv2026

Coordinated beak-tongue mechanics enable dexterous seed manipulation in songbirds

Dexterous manipulation of objects relies on precise coordination between anatomical elements. In seed-eating birds, seeds are manipulated and dehusked using both the beak and tongue, but the functional roles and coordination of these structures remain unresolved. Here, we quantified the 3D movements of the upper beak, lower beak, tongue, and seed in a hard-biting and a weak-biting songbird species using X-ray Reconstruction of Moving Morphology (XROMM) and measured contractile properties of their primary jaw muscles. We show that the tongue serves as the main tool for seed rotation, transport, and stabilization. Multi-dimensional, high-frequency movements of the upper and lower beaks reveal that efficient seed processing depends on high mobility of the kinetic avian skull. Strong and weak biters differ in feeding kinematics and jaw muscle speeds, suggesting ecological specialization of cranial mechanics. The complexity, precision, and tight coordination of beak and tongue motions show that the avian cranium rivals the dexterity of the primate hand despite limited degrees of freedom.

ecology↗

bioRxiv2024

Joint and tissue mechanics in post-traumatic osteoarthritis: insights from the rat model

ObjectiveAltered mechanical loading is a known risk factor for osteoarthritis. Destabilization of the medial meniscus (DMM) is a preclinical gold standard model for post-traumatic osteoarthritis and is thought to induce instability and locally increased loading. However, the joint- and tissue-level mechanical environment underlying cartilage degeneration remains poorly documented. DesignUsing a custom multiscale modeling approach, we assessed joint and tissue biomechanics in rats undergoing sham surgery and DMM. High-fidelity experimental gait data were collected in a setup combining biplanar fluoroscopy and a ground reaction force plate. Knee poses and joint-level loading were estimated through musculoskeletal modeling, using bony landmarks, semi-automatically tracked via deep learning on fluoroscopic images, and ground reaction forces. A musculoskeletal model of the rat hindlimb was adapted to represent knee flexion-extension, valgus-varus, and internal-external rotation. The tissue-level cartilage mechanical environment was then spatially estimated, using the musculoskeletal modeling parameters as inputs into a dedicated finite element (FE) model of the rat knee, comprising cartilage and meniscal tissues. Experimental gait data and modeling workflows, including musculoskeletal models and FE meshes, are openly shared through a data repository. ResultsIn rats with DMM, the frontal plane knee pose was altered, yet there was no indication of joint-level overloading. Tissue-level mechanical cues typically linked with cartilage degeneration were not increased in the medial tibial cartilage, despite evidence of tissue structural changes. ConclusionDMM did not increase joint and tissue mechanical responses in the knee medial compartment, suggesting that mechanical loading alone does not explain the observed osteoarthritis-like structural changes.

bioengineering↗

bioRxiv2021

In vivo intraoral waterflow quantification reveals hidden mechanisms of suction feeding in fish

Virtually all fish rely on flows of water to transport food to the back of their pharynx. While external flows that draw food into the mouth are well described, how intra-oral water flows manage to deposit food at the esophagus entrance remains unknown. In theory, the posteriorly moving water must, at some point, curve laterally and/or ventrally to exit through the gill slits. Such flows would eventually carry food away from the esophagus instead of towards it. This apparent paradox calls for a filtration mechanism to deviate food from the suction-feeding streamlines. To study this gap in our fundamental understanding of how fish feed, we developed and applied a new technique to quantify three-dimensional patterns of intra-oral water flows in vivo. We combined stereoscopic high-speed x-ray videos to quantify skeletal motion (XROMM) with 3D x-ray particle tracking (XPT) of approximately neutrally buoyant spheres of 1.4 mm in diameter. We showed, for carp (Cyprinus carpio) and tilapia (Oreochromis niloticus), that water tracers displayed higher curvatures than food tracers, indicating an inertia-driven filtration. In addition, tilapia also exhibited a central jet flow pattern, which aids in quickly carrying food to the pharyngeal jaw region. When the food was trapped at the branchial basket, it was resuspended and carried more centrally by periodical bidirectional waterflows, synchronized with head-bone motions. By providing a complete picture of the suction-feeding process and revealing fundamental differences in food transport mechanisms among species, this new technique opens a new area of investigation to fully understand how most aquatic vertebrates feed.

evolutionary biology↗