scholarly journals The initiation knot is a signaling center required for molar tooth development

Development ◽  
2021 ◽  
Vol 148 (9) ◽  
Author(s):  
Isabel Mogollón ◽  
Jacqueline E. Moustakas-Verho ◽  
Minna Niittykoski ◽  
Laura Ahtiainen
Keyword(s):  
Tooth Development ◽  
Molar Tooth ◽  
Proliferating Cells ◽  
Cell Dynamics ◽  
Confocal Fluorescence ◽  
Signaling Center ◽  
Embryonic Morphogenesis ◽  
Enamel Knots ◽  
Confocal Fluorescence Imaging ◽  
Center Cell

ABSTRACT Signaling centers, or organizers, regulate many aspects of embryonic morphogenesis. In the mammalian molar tooth, reiterative signaling in specialized centers called enamel knots (EKs) determines tooth patterning. Preceding the primary EK, transient epithelial thickening appears, the significance of which remains debated. Using tissue confocal fluorescence imaging with laser ablation experiments, we show that this transient thickening is an earlier signaling center, the molar initiation knot (IK), that is required for the progression of tooth development. IK cell dynamics demonstrate the hallmarks of a signaling center: cell cycle exit, condensation and eventual silencing through apoptosis. IK initiation and maturation are defined by the juxtaposition of cells with high Wnt activity to Shh-expressing non-proliferating cells, the combination of which drives the growth of the tooth bud, leading to the formation of the primary EK as an independent cell cluster. Overall, the whole development of the tooth, from initiation to patterning, is driven by the iterative use of signaling centers.

scholarly journals The Initiation Knot is a Signaling Center Required for Molar Tooth Development

2020 ◽  
Author(s):  
Isabel Mogollón ◽  
Jacqueline E. Moustakas-Verho ◽  
Minna Niittykoski ◽  
Laura Ahtiainen
Keyword(s):  
Tooth Development ◽  
Molar Tooth ◽  
Proliferating Cells ◽  
Cell Dynamics ◽  
Confocal Fluorescence ◽  
Signaling Center ◽  
Embryonic Morphogenesis ◽  
Enamel Knots ◽  
Confocal Fluorescence Imaging ◽  
Center Cell

SummarySignaling centers, or organizers, regulate many aspects of embryonic morphogenesis. In the mammalian molar tooth, reiterative signaling in specialized centers called enamel knots (EKs) determine tooth patterning. Preceding the first, primary EK, a transient epithelial thickening appears whose significance remains debated. Here, using tissue confocal fluorescence imaging with laser ablation experiments, we show that this transient thickening is an earlier signaling center, the molar initiation knot (IK) that is required for the progression of tooth development. IK cell dynamics manifest the hallmarks of a signaling center; cell cycle exit, condensation, and eventual silencing through apoptosis. IK initiation and maturation are defined by the juxtaposition of high Wnt activity cells to Shh-expressing non-proliferating cells, the combination of which drives the growth of the tooth bud, leading to the formation of the primary EK as an independent cell cluster. Overall, the whole development of the tooth, from initiation to patterning, is driven by the iterative use of signaling centers.

Confocal Fluorescence Imaging of Photosensitised DNA Denaturation in Cell Nuclei

2005 ◽  
Author(s):  
Tytus Bernas ◽  
Elikplimi K. Asem ◽  
J. Paul Robinson ◽  
Peter R. Cook ◽  
Jurek W. Dobrucki
Keyword(s):  
Fluorescence Imaging ◽  
Dna Denaturation ◽  
Cell Nuclei ◽  
Confocal Fluorescence ◽  
Confocal Fluorescence Imaging

Expression of neural cell-adhesion molecule mRNA during mouse molar tooth development

2002 ◽  
Vol 47 (11) ◽  
pp. 805-813 ◽  
Author(s):  
Nobuko Obara ◽  
Yuko Suzuki ◽  
Yasuko Nagai ◽  
Hiromasa Nishiyama ◽  
Itaru Mizoguchi ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Adhesion Molecule ◽  
Cell Adhesion Molecule ◽  
Neural Cell Adhesion Molecule ◽  
Tooth Development ◽  
Neural Cell ◽  
Molar Tooth ◽  
Neural Cell Adhesion

Age Distribution of Red Tree Voles in Northern Spotted Owl Pellets Estimated from Molar Tooth Development

2020 ◽  
Vol 93 (3-4) ◽  
pp. 193
Author(s):  
Chad A. Marks-Fife ◽  
Eric D. Forsman ◽  
Katie M. Dugger
Keyword(s):  
Tooth Development ◽  
Age Distribution ◽  
Molar Tooth ◽  
Spotted Owl ◽  
Northern Spotted Owl ◽  
Owl Pellets

scholarly journals Expression, localization and synthesis of small leucine-rich proteoglycans in developing mouse molar tooth germ

2020 ◽  
Vol 64 (1) ◽  
Author(s):  
Angammana Randilini ◽  
Kaoru Fujikawa ◽  
Shunichi Shibata
Keyword(s):  
Organ Culture ◽  
Developmental Stages ◽  
Tooth Development ◽  
Expression Patterns ◽  
Tooth Germ ◽  
Molar Tooth ◽  
Cervical Region ◽  
Metabolic Labeling ◽  
Tooth Formation ◽  
Tooth Germs

The gene expression and protein synthesis of small leucine-rich proteoglycans (SLRPs), including decorin, biglycan, fibromodulin, and lumican, was analyzed in the context of the hypothesis that they are closely related to tooth formation. In situ hybridization, immunohistochemistry, and organ culture with metabolic labeling of [35S] were carried out in mouse first molar tooth germs of different developmental stages using ICR mice at embryonic day (E) 13.5 to postnatal day (P) 7.0. At the bud and cap stage, decorin mRNA was expressed only in the surrounding mesenchyme, but not within the tooth germ. Biglycan mRNA was then expressed in the condensing mesenchyme and the dental papilla of the tooth germ. At the apposition stage (late bell stage), both decorin and biglycan mRNA were expressed in odontoblasts, resulting in a switch of the pattern of expression within the different stages of odontoblast differentiation. Decorin mRNA was expressed earlier in newly differentiating odontoblasts than biglycan. With odontoblast maturation and dentin formation, decorin mRNA expression was diminished and localized to the newly differentiating odontoblasts at the cervical region. Simultaneously, biglycan mRNA took over and extended its expression throughout the new and mature odontoblasts. Both mRNAs were expressed in the dental pulp underlying the respective odontoblasts. At P7.0, both mRNAs were weakly expressed but maintained their spatial expression patterns. Immunostaining showed that biglycan was localized in the dental papillae and pulp. In addition, all four SLRPs showed clear immunostaining in predentin, although the expressions of fibromodulin and lumican mRNAs were not identified in the tooth germs examined. The organ culture data obtained supported the histological findings that biglycan is more predominant than decorin at the apposition stage. These results were used to identify biglycan as the principal molecule among the SLRPs investigated. Our findings indicate that decorin and biglycan show spatial and temporal differential expressions and play their own tissue-specific roles in tooth development.

scholarly journals Regeneration of the flatworm Prosthiostomum siphunculus (Polycladida, Platyhelminthes)

2020 ◽  
Author(s):  
Tamara Schadt ◽  
Veronika Prantl ◽  
Alexandra L Grosbusch ◽  
Philip Bertemes ◽  
Bernhard Egger
Keyword(s):  
Stem Cell ◽  
Wound Closure ◽  
The Other ◽  
Regeneration Capacity ◽  
Proliferating Cells ◽  
Free Living ◽  
Cell Dynamics ◽  
Head Regeneration ◽  
The Brain ◽  
Regeneration Blastema

Abstract Fueled by the discovery of head regeneration in triclads (planarians) two and a half centuries ago, flatworms have been the focus of regeneration research. But not all flatworms can regenerate equally well and to obtain a better picture of the characteristics and evolution of regeneration in flatworms other than planarians, the regeneration capacity and stem cell dynamics during regeneration in the flatworm order Polycladida are studied. Here, we show that as long as the brain remained at least partially intact, the polyclad Prosthiostomum siphunculus was able to regenerate submarginal eyes, cerebral eyes, pharynx, intestine and sucker. In the complete absence of the brain only wound closure was observed but no regeneration of missing organs. Amputated parts of the brain could not be regenerated. The overall regeneration capacity of P. siphunculus is a good fit for category III after a recently established system, in which most polyclads are currently classified. Intact animals showed proliferating cells in front of the brain which is an exception compared with most of the other free-living flatworms that have been observed so far. Proliferating cells could be found within the regeneration blastema, similar to all other flatworm taxa except triclads. No proliferation was observed in epidermis and pharynx. In pulse-chase experiments, the chased cells were found in all regenerated tissues and thereby shown to differentiate and migrate to replace the structures lost upon amputation.

Pore selectivity and electron transfers in HZSM-5 single crystals: a Raman microspectroscopy mapping and confocal fluorescence imaging combined study

2020 ◽  
Vol 22 (22) ◽  
pp. 12745-12756
Author(s):  
A. Moissette ◽  
M. Hureau ◽  
M. Moreau ◽  
J. P. Cornard
Keyword(s):  
Single Crystals ◽  
Fluorescence Imaging ◽  
Single Particle ◽  
Raman Microspectroscopy ◽  
Single Particle Level ◽  
Confocal Fluorescence ◽  
Particle Level ◽  
Confocal Fluorescence Imaging ◽  
Electron Transfers

Electron transfers at the single particle level in HZSM-5 zeolite are followed by combining Raman microspectroscopy mapping and confocal fluorescence imaging. The effects of pore accessibility and guest diffusion on reactivity are investigated.

Neonatal hamster molar tooth development: Extraction and characterization of amelogenins, enamelins, and soluble dentin proteins

1982 ◽  
Vol 34 (1) ◽  
pp. 86-96 ◽  
Author(s):  
D. M. Lyaruu ◽  
A. Belcourt ◽  
A. G. Fincham ◽  
J. D. Termine
Keyword(s):  
Tooth Development ◽  
Molar Tooth
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