PHENOTYPIC ANALYSIS OF LONG BONES IN PANNEXIN 3 KNOCKOUT MICE

Pannexin 3 (Panx3) is a channel forming glycoprotein that is highly expressed in skeletal tissues. Panx3 is induced at the growth plate of long bones where it regulates cell proliferation and differentiation, a key role in bone formation. This study analyzes the phenotype of long bones in a novel Panx3 knockout (KO) mouse to assess the role of Panx3 in bone formation. Ten KO and 10 wild-type (WT) adult mice were scanned using in vivo micro-CT. Right femora / humeri were digitized using homologous landmarks. Geometric morphometric analysis (multivariate statistical methods) allowed for quantitative comparison of shape, size and variation between KO and WT long bones. KO mice demonstrated distinct long bone shape differences. A significant amount of this difference, 20-30%, can be attributed to the allometric component of shape. When scaled, WT bones have proportionally longer diaphyses and KO bones have larger bony prominences and epiphyses. Analysis of long bone cross-sectional geometric properties revealed thicker diaphyses in KO mice, equaling greater resistance to torsion and compression. KO mice appear to have altered long bone growth patterns, implicating a role for Panx3 in maintaining optimum skeletal growth

Global deletion of Panx3 produces multiple phenotypic effects in mouse humeri and femora

© 2016 Anatomical Society. Pannexins form single-membrane channels that allow passage of small molecules between the intracellular and extracellular compartments. Of the three pannexin family members, Pannexin3 (Panx3) is the least studied but is highly expressed in skeletal tissues and is thought to play a role in the regulation of chondrocyte and osteoblast proliferation and differentiation. The purpose of our study is to closely examine the in vivo effects of Panx3 ablation on long bone morphology using micro-computed tomography. Using Panx3 knockout (KO) and wildtype (WT) adult mice, we measured and compared aspects of phenotypic shape, bone mineral density (BMD), cross-sectional geometric properties of right femora and humeri, and lean mass. We found that KO mice have absolutely and relatively shorter diaphyseal shafts compared with WT mice, and relatively larger areas of muscle attachment sites. No differences in BMD or lean mass were found between WT and KO mice. Interestingly, KO mice had more robust femora and humeri compared with WT mice when assessed in cross-section at the midshaft. Our results clearly show that Panx3 ablation produces phenotypic effects in mouse femora and humeri, and support the premise that Panx3 has a role in regulating long bone growth and development

Causes and consequences of ontogenetic dietary shifts: a global synthesis using fish models

Accepted manuscript version. Published version available at https://doi.org/10.1111/brv.12468. Ontogenetic dietary shifts (ODSs), the changes in diet utilisation occurring over the life span of an individual consumer, are widespread in the animal kingdom. Understanding ODSs provides fundamental insights into the biological and ecological processes that function at the individual, population and community levels, and is critical for the development and testing of hypotheses around key concepts in trophic theory on model organisms. Here, we synthesise historic and contemporary research on ODSs in fishes, and identify where further research is required. Numerous biotic and abiotic factors can directly or indirectly influence ODSs, but the most influential of these may vary spatially, temporally and interspecifically. Within the constraints imposed by prey availability, we identified competition and predation risk as the major drivers of ODSs in fishes. These drivers do not directly affect the trophic ontogeny of fishes, but may have an indirect effect on diet trajectories through ontogenetic changes in habitat use and concomitant changes in prey availability. The synthesis provides compelling evidence that ODSs can have profound ecological consequences for fish by, for example, enhancing individual growth and lifetime reproductive output or reducing the risk of mortality. ODSs may also influence food‐web dynamics and facilitate the coexistence of sympatric species through resource partitioning, but we currently lack a holistic understanding of the consequences of ODSs for population, community and ecosystem processes and functioning. Studies attempting to address these knowledge gaps have largely focused on theoretical approaches, but empirical research under natural conditions, including phylogenetic and evolutionary considerations, is required to test the concepts. Research focusing on inter‐individual variation in ontogenetic trajectories has also been limited, with the complex relationships between individual behaviour and environmental heterogeneity representing a particularly promising area for future research

Tips of Fingers, Tips of Tongues: Emulating authentic dialogue in roleplaying video games

Dialogue systems are integral mechanics in roleplaying video games, as forms of worldbuilding that acknowledge player choice. Early conceptions of game dialogue in text adventure games let players type in whatever they want to say, in attempts to emulate true conversational fidelity. However, their rudimentary structures limit the possibility of direct and topical responses to typed input, breaking immersion within the game. Furthermore, consumer shifts in primary gaming platforms, from personal computers to dedicated video game consoles, influence how dialogue is designed within technological restraints. This thesis examines how video game dialogue effectively mimics conversations with the player while maintaining a sense of immersion despite platform limitations. An exploration of critical game design factors, including the balance between gameplay and narrative, reveals how dialogue systems historically shift from freeform designs to more scripted structures. Though a consideration and application of commonly-used game design strategies in other development areas, this thesis promotes innovation in dialogue system design, offering new potentials for play.Les systèmes de dialogue sont des mécanismes intégraux qui reconnaissent les choix du joueur dans les jeux de rôle en tant que formes de worldbuilding. Les premières conceptions du dialogue dans les jeux d'aventure textuels permettent aux joueurs d’entrer ce qu’ils veulent, afin d'imiter la fidélité d’une conversation. Cependant, leurs structures rudimentaires limitent la possibilité de réponses directes et topiques à l'entrée dactylographiée, brisant l'immersion dans le jeu. De plus, les changements de consommation dans les plates-formes de jeu primaires depuis les ordinateurs personnels jusqu'aux consoles de jeux vidéo dédiées influencent la façon dont le dialogue est conçu dans le cadre des contraintes technologiques. Cette thèse examine comment le dialogue dans le jeu vidéo imite efficacement les conversations avec le joueur tout en conservant un sentiment d'immersion malgré les limites de la plate-forme. Une exploration des facteurs critiques de la conception du jeu, y compris l'équilibre entre le gameplay et le récit, révèle comment les systèmes de dialogue se sont historiquement éloignés des conceptions libres vers des structures plus scénarisées. Bien qu'il s'agisse d'une considération et d’une application de stratégies de conception de jeu couramment utilisées dans d'autres domaines de développement, cette thèse encourage l'innovation dans la conception de systèmes de dialogue, offrant de nouveaux potentiels de jeu

Reading and relating: Digitally tracing human groupings in the illustrations of the Utrecht Psalter

Within the illustrations of the ninth century Utrecht Psalter, groupings of multiple people with no imperative role in the narrative are found in large numbers. This inclusion is unique and with clear intention, and unlike other non-essential pictorial elements in the composition such as foliage or buildings, all of these figures are drawn to completion. As the images in the Utrecht Psalter show consistency in their measurements on the page, as well as through the scale of elements within the actual illustrations, direct comparisons can be made on how these figures are employed in the scene. By using digital applications to create a compositional overlay of all these groups, a concentration of figures on the left and right sides of the image is observed. This article suggests that such an arrangement provides a readable image, with human groups added in order to encourage engagement with the text of the Psalter and aid in remembering its messages. Keywords: Utrecht Psalter; medieval literacy; manuscript illustration; image composition; digital humanities; artwork engagemen

All Work and No Play? Materiality and Interactivity in Eighteenth-Century Girls’ Education and Literature

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Diet of a rare Canadian fish species, Carmine Shiner (Notropis percobromus) in the Birch River, Manitoba, Canada

Due to its restricted occurrence and existing threats, Carmine Shiner (Notropis percobromus) has been listed as threatened under the Canadian Species at Risk Act. Little is known about Carmine Shiner biology, and understanding its diet composition will help inform future conservation actions. Consequently, the aim of this study was to analyze the diet of Carmine Shiner. Fish were caught throughout the open water season using beach seines, and stomach contents were analyzed. Carmine Shiner feed on a variety of terrestrial and aquatic insects. Diets did not differ substantially between year classes, and we observed no clear temporal trends in diet composition

Biomass Reallocation between Juveniles and Adults Mediates Food Web Stability by Distributing Energy Away from Strong Interactions

<div><p>Ecological theory has uncovered dynamical differences between food web modules (i.e. low species food web configurations) with only species-level links and food web modules that include within-species links (e.g. non-feeding links between mature and immature individuals) and has argued that these differences ought to cause food web theory that includes within-species links to contrast with classical food web theory. It is unclear, however, if life-history will affect the observed connection between interaction strength and stability in species-level theory. We show that when the predator in a species-level food chain is split into juvenile and adult stages using a simple nested approach, stage-structure can mute potentially strong interactions through the transfer of biomass within a species. Within-species biomass transfer distributes energy away from strong interactions promoting increased system stability consistent with classical food web theory.</p></div