Abstract:Mammalian teeth have diverse pattern of the crown and root. The patterning mechanism of the root position and number is relatively unknown compared to that of the crown. The root number does not always match to the cusp number, which has prevented the complete understanding of root patterning. In the present study, to elucidate the mechanism of root pattern formation, we examined (1) the pattern of cervical tongues, which are tongue-like epithelial processes extending from cervical loops, (2) factors influenci… Show more
“…Suppression of Shh signaling activity in vitro increases the number of cusps in wild-type tooth germs. However, after suppression of Shh signaling activity in vitro, the crown outlines of tooth germs (Seo et al 2017) are accompanied by severe changes in cusp pattern, making it impossible to distinguish supernumerary from preexisting cusps. Suppression of Shh activity leads to a slight increase in the number of cusps in vivo in Eda -null mice (Harjunmaa et al 2014).…”
Crown shapes in mammalian teeth vary considerably from species to species, and morphological characters in crown shape have been used to identify species. Cusp pattern is one of the characters in crown shape. In the processes governing the formation of cusp pattern, the Shh pathway has been implicated as an important player. Suppression of Shh signaling activity in vitro in explant assays appears to induce supernumerary cusp formation in wild-type tooth germs. However, the in vivo role of Shh signaling in cusp pattern formation and the molecular mechanisms by which Shh regulates cusp patterning are not clear. Here, through in vivo phenotypic analyses of mice in which Shh activity was suppressed and compared with wild-type mice, we characterized differences in the location, number, incidence, and shape of supernumerary cusps in molars at embryonic day 15.5. We found that the distances between cusps were reduced in molars of Shh activityâsuppressed mice in vivo. These findings confirm and extend the previous idea that Shh acts as an inhibitor in the reaction-diffusion model for cusp pattern formation by negatively regulating the intercuspal distance. We uncovered a significant reduction of expression level of Sostdc1, which encodes a secreted modulator of Wnt signaling, after suppression of Shh activity. The supernumerary cusp formation in Sostdc1â/â mice and compound Sostdc1 and Lrp mutant mice indicates a strong association between Wnt and Shh signaling pathways in cusp patterning. In further support of this idea, there is a high degree of similarity in the supernumerary cusp patterns of mice lacking Sostdc1 or Shh at embryonic day 15.5. These results suggest that Shh plays an inhibitory role in cusp pattern formation by modulating Wnt signaling through the positive regulation of Sostdc1.
“…Suppression of Shh signaling activity in vitro increases the number of cusps in wild-type tooth germs. However, after suppression of Shh signaling activity in vitro, the crown outlines of tooth germs (Seo et al 2017) are accompanied by severe changes in cusp pattern, making it impossible to distinguish supernumerary from preexisting cusps. Suppression of Shh activity leads to a slight increase in the number of cusps in vivo in Eda -null mice (Harjunmaa et al 2014).…”
Crown shapes in mammalian teeth vary considerably from species to species, and morphological characters in crown shape have been used to identify species. Cusp pattern is one of the characters in crown shape. In the processes governing the formation of cusp pattern, the Shh pathway has been implicated as an important player. Suppression of Shh signaling activity in vitro in explant assays appears to induce supernumerary cusp formation in wild-type tooth germs. However, the in vivo role of Shh signaling in cusp pattern formation and the molecular mechanisms by which Shh regulates cusp patterning are not clear. Here, through in vivo phenotypic analyses of mice in which Shh activity was suppressed and compared with wild-type mice, we characterized differences in the location, number, incidence, and shape of supernumerary cusps in molars at embryonic day 15.5. We found that the distances between cusps were reduced in molars of Shh activityâsuppressed mice in vivo. These findings confirm and extend the previous idea that Shh acts as an inhibitor in the reaction-diffusion model for cusp pattern formation by negatively regulating the intercuspal distance. We uncovered a significant reduction of expression level of Sostdc1, which encodes a secreted modulator of Wnt signaling, after suppression of Shh activity. The supernumerary cusp formation in Sostdc1â/â mice and compound Sostdc1 and Lrp mutant mice indicates a strong association between Wnt and Shh signaling pathways in cusp patterning. In further support of this idea, there is a high degree of similarity in the supernumerary cusp patterns of mice lacking Sostdc1 or Shh at embryonic day 15.5. These results suggest that Shh plays an inhibitory role in cusp pattern formation by modulating Wnt signaling through the positive regulation of Sostdc1.
“…1a-c). [1][2][3][4] Over the last three decades, substantial progress has been achieved in creating such structural colors in the laboratory. [5][6][7][8][9][10][11][12][13][14][15] As opposed to the colors of dyes and pigments, which are based on the absorption of light, structural color arises due to diffraction, refraction and reflection of light by submicron scale structures.…”
mentioning
confidence: 99%
“…The condition of constructive interference leading to maximum reflectance in a 1D PC is equivalent to the photonic stop band or photonic band gap. From eqn (2) and (3), one can see that by changing the material thickness or the RI, a color change can be achieved. Hence, stimuli which induce a change in either n i , or l i , or both, can be detected (Fig.…”
The ability to produce structural color from inherently colorless materials, similar to that in butterfly wings and beetle shells, has attracted considerable research interest over the last three decades. Despite their extraordinary properties and performances, the field of structural colors based on inherently functional 2D materials only took off recently. In this minireview, we highlight the diversity of 2D materials utilized for achieving structural coloration in different architectures. We summarize the large tunability of photonic architectures based on 2D materials and emphasize their extraordinary dynamic response induced by external stimuli. Subsequently, recent strategies to tailor their properties with molecular and structural approaches are discussed. Finally, we point out promising future directions in this emerging field. Structural coloroverview and concepts 566 | Mol. Syst. Des. Eng., 2019, 4, 566-579 This journal is
Design, System, ApplicationAs 2D materials are coming of age, their richness in composition, structure and properties offer a unique platform for the design of tailor-made nanoscale building blocks for functional devices. Combining the chemical scope, diverse optical properties and stimuli-responsive nature of 2D materials and their ensembles with the recent advancement in liquid-assisted assembly strategies, 2D materials have emerged as versatile building blocks in thin film-based photonic architectures, including Fabry-PĂŠrot interference filters and 1D photonic crystals. To impart such architectures with maximum functionality, design strategies range from molecular level approaches such as ion exchange and intercalation, to morphology engineering such as porosity tuning. The integration of 2D materials into photonic architectures has opened up new horizons in the realization of smart devices, ranging from vapor and pressure sensors to functional surfaces allowing for the touchless tracking of finger motions. On a more fundamental level, thin films exhibiting tunable structural color allow for the observation of otherwise optically silent processes with the naked eye, such as intercalation into 2D materials. Cast into photonic architectures, the unique versatility of 2D materials and their molecularly engineered counterparts can be harvested to push the limits of label-free sensing, anticounterfeiting, radiation shielding, photovoltaics, display technology, and beyond.
“…Its reduced size and the absence of the pulp cavity indicate that it is a non-functional root. Such a condition has been reported in some extant and fossil carnivorans 20 â 23 , although the origin of this anomaly is not clear because patterning mechanism of the root position and number is still poorly known 24 . Figure 6 3D models of the teeth of Acinonyx pardinensis from Monte Argentario.…”
We describe here a partial skull with associated mandible of a large felid from Monte Argentario, Italy (Early Pleistocene; ~1.5 million years). Propagation x-ray phase-contrast synchrotron microtomography of the specimen, still partially embedded in the rock matrix, allows ascribing it reliably to Acinonyx pardinensis, one of the most intriguing extinct carnivorans of the Old World Plio-Pleistocene. The analysis of images and 3D models obtained through synchrotron microtomography â here applied for the first time on a Plio-Pleistocene carnivoran â reveals a mosaic of cheetah-like and Panthera-like features, with the latter justifying previous attributions of the fossil to the extinct Eurasian jaguar Panthera gombaszoegensis. Similarly, we reassign to A. pardinensis some other Italian materials previously referred to P. gombaszoegensis (sites of Pietrafitta and Ellera di Corciano). The recognition of Panthera-like characters in A. pardinensis leads to reconsidering the ecological role of this species, whose hunting strategy was likely to be different from those of the living cheetah. Furthermore, we hypothesise that the high intraspecific variation in body size in A. pardinensis can be the result of sexual dimorphism, as observed today in all large-sized felids.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citationsâcitations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
