Inductive interactions in early amphibian development and their general nature

Development ◽  
1985 ◽  
Vol 89 (Supplement) ◽  
pp. 333-347
Author(s):  
P. D. Nieuwkoop
Keyword(s):  
Neural Tube ◽  
Large Scale ◽  
Tube Formation ◽  
Cell Interactions ◽  
General Nature ◽  
Short Discussion ◽  
Regional Pattern ◽  
Germ Layers ◽  
Inductive Interaction ◽  
Morphogenic Process

After a short discussion on cell interactions in general and inductive interactions in particular, the almost completely epigenetic nature of amphibian development is emphasized. In the symmetrized egg undergoing cleavage a large-scale inductive interaction occurs which leads to the formation of the meso—endoderm. Meso—endoderm formation gives rise to the morphogenic process of gastrulation. In the ensuing triple-layered embryo inductive interactions are strongly enhanced. The following large-scale inductive interaction leads to the formation of the neural anlage. This is again followed by the morphogenetic process of neurulation or neural tube formation. Subsequent interactions between the germ layers of the triple-layered embryo give rise to the formation of the regional pattern of organ anlagen. Finally, the most promising approaches to the nature of inductive interactions for mesoderm and endoderm formation are discussed.

The Effects of β-Mercaptoethanol on the Morphogenetic Movements of Amphibian Embryos

Development ◽  
1963 ◽  
Vol 11 (1) ◽  
pp. 155-166
Author(s):  
P. Malpoix ◽  
J. Quertier ◽  
J. Brachet
Keyword(s):  
Neural Tube ◽  
Tube Formation ◽  
Animal Pole ◽  
Morphogenetic Movements ◽  
Complete Development ◽  
Early Stages ◽  
Amphibian Embryos ◽  
Biological Specificity ◽  
Neural Tube Formation

The inhibition by β-mercaptoethanol of morphogenesis in amphibians, freshwater hydra, planarians and regenerating tadpoles, has already been reported by one of us (Brachet, 1958, 1959a, b, c). The present work provides a closer analysis of the biological specificity of j8-mercaptoethanol with regard to the different movements which produce gastrulation in amphibians: invagination, epiboly, convergent stretching and ingression. The main result, obtained with Pleurodeles, was that gastrulation is completely inhibited by M/100 β-mercaptoethanol. Lower concentrations (M/300) permit more complete development, but the resulting embryos are abnormal. β-Mercaptoethanol interferes with neural tube formation, but has less effect on the development of the notochord and the mesodermal somites. It was further noted that, when embryos are treated at very early stages (1–2 cells, young blastulae), the blastocoele seems to collapse and the ectoblast of the animal pole is deeply puckered.

scholarly journals Characterizing the nature and variability of avalanche hazard in western Canada

2018 ◽  
Author(s):  
Bret Shandro ◽  
Pascal Haegeli
Keyword(s):  
Large Scale ◽  
General Nature ◽  
Western Canada ◽  
Self Organizing Maps ◽  
Avalanche Hazard ◽  
Problem Types ◽  
Comprehensive Picture ◽  
Location Study ◽  
Insight Into ◽  
Avalanche Risk Management

Abstract. The snow and avalanche climate types maritime, continental and transitional are well established and have been used extensively to characterize the general nature of avalanche hazard at a location, study interseasonal and large-scale spatial variabilities and provide context for the design of avalanche safety operations. While researchers and practitioners have an experience-based understanding of the avalanche hazard associated with the three climate types, no studies have described the hazard character of an avalanche climate in detail. Since the 2009/10 winter, the consistent use of Statham et al.'s (2017) conceptual model of avalanche hazard in public avalanche bulletins in Canada created a new quantitative record of avalanche hazard that offers novel opportunities for addressing this knowledge gap. We identified typical daily avalanche hazard situations using Self Organizing Maps (SOM) and then calculated seasonal prevalence values of these situations. This approach produces a concise characterization measure that is conducive to statistical analyses, but still provides a comprehensive picture that is informative for avalanche risk management due to its link to avalanche problem types. Hazard situation prevalence values for individual seasons, elevations bands and forecast regions provide unprecedented insight into the interseasonal and spatial variability of avalanche hazard in western Canada.

Local and transient expression of E-cadherin involved in mouse embryonic brain morphogenesis

Development ◽  
1992 ◽  
Vol 116 (4) ◽  
pp. 1011-1019 ◽  
Author(s):  
K. Shimamura ◽  
M. Takeichi
Keyword(s):  
Pattern Formation ◽  
Transient Expression ◽  
Neural Tube ◽  
Single Cells ◽  
Embryonic Brain ◽  
Antibody Treatment ◽  
Regional Pattern ◽  
Dorsal Midline ◽  
Cellular Events ◽  
E Cadherin

We found that E-cadherin (uvomorulin) is transiently expressed in restricted regions of the metencephalon, mesencephalon and diencephalon of mouse embryonic brain. This expression first occurred in parts of the mesencephalon and diencephalon at around E9.5, and subsequently extended to the primordia of cerebellum, the dorsal midline of mesencephalon and some other regions of the embryonic brain. These E-cadherin expressions ceased by E15 except at the dorsal midline. Immunohistological analyses showed that E-cadherin-positive cells are radially arranged in the neural tube and the E-cadherin-positive regions are sharply demarcated from E-cadherin-negative regions. Axons extending from some of the E-cadherin-positive regions also expressed this molecule. When embryonic brains were dissociated into single cells and cultured as monolayers, E-cadherin-positive cells formed clusters that were segregated from E-cadherin-negative cells. E9.5 brain fragments containing metencephalon and mesencephalon were isolated, explanted on Nucleopore filters and cultured in the absence or presence of antibodies to E-cadherin. This antibody treatment removed most of the E-cadherin molecules from the explants and consequently affected their growth pattern. To analyze cellular events induced by the antibody treatment, we stained these explants with an antiserum to En whose distribution was found to overlap in part with that of E-cadherin and found that the pattern of En staining was altered by the anti-E-cadherin antibody treatment. These results suggest that the local and transient expression of E-cadherin in embryonic brain is involved in regional pattern formation in this organ.

scholarly journals Microbial Interactions in Oral Communities Mediate Emergent Biofilm Properties

2019 ◽  
Vol 99 (1) ◽  
pp. 18-25 ◽  
Author(s):  
P.I. Diaz ◽  
A.M. Valm
Keyword(s):  
Large Scale ◽  
Taxonomic Composition ◽  
Cell Interactions ◽  
Microbial Interactions ◽  
Spatial Proximity ◽  
Individual Species ◽  
Emergent Properties ◽  
Oral Diseases ◽  
Metabolic Cooperation ◽  
Cell Cell

Oral microbial communities are extraordinarily complex in taxonomic composition and comprise interdependent biological systems. The bacteria, archaea, fungi, and viruses that thrive within these communities engage in extensive cell-cell interactions, which are both beneficial and antagonistic. Direct physical interactions among individual cells mediate large-scale architectural biofilm arrangements and provide spatial proximity for chemical communication and metabolic cooperation. In this review, we summarize recent work in identifying specific molecular components that mediate cell-cell interactions and describe metabolic interactions, such as cross-feeding and exchange of electron acceptors and small molecules, that modify the growth and virulence of individual species. We argue, however, that although pairwise interaction models have provided useful information, complex community-like systems are needed to study the properties of oral communities. The networks of multiple synergistic and antagonistic interactions within oral biofilms give rise to the emergent properties of persistence, stability, and long-range spatial structure, with these properties mediating the dysbiotic transitions from health to oral diseases. A better understanding of the fundamental properties of interspecies networks will lead to the development of effective strategies to manipulate oral communities.

scholarly journals Apical Accumulation of Rho in the Neural Plate Is Important for Neural Plate Cell Shape Change and Neural Tube Formation

2008 ◽  
Vol 19 (5) ◽  
pp. 2289-2299 ◽  
Author(s):  
Nagatoki Kinoshita ◽  
Noriaki Sasai ◽  
Kazuyo Misaki ◽  
Shigenobu Yonemura
Keyword(s):  
Neural Tube ◽  
Rho Gtpases ◽  
Cell Shape ◽  
Shape Change ◽  
Myosin Ii ◽  
Tube Formation ◽  
Neural Plate ◽  
Cell Shape Change ◽  
Neural Tube Formation

Although Rho-GTPases are well-known regulators of cytoskeletal reorganization, their in vivo distribution and physiological functions have remained elusive. In this study, we found marked apical accumulation of Rho in developing chick embryos undergoing folding of the neural plate during neural tube formation, with similar accumulation of activated myosin II. The timing of accumulation and biochemical activation of both Rho and myosin II was coincident with the dynamics of neural tube formation. Inhibition of Rho disrupted its apical accumulation and led to defects in neural tube formation, with abnormal morphology of the neural plate. Continuous activation of Rho also altered neural tube formation. These results indicate that correct spatiotemporal regulation of Rho is essential for neural tube morphogenesis. Furthermore, we found that a key morphogenetic signaling pathway, the Wnt/PCP pathway, was implicated in the apical accumulation of Rho and regulation of cell shape in the neural plate, suggesting that this signal may be the spatiotemporal regulator of Rho in neural tube formation.

scholarly journals Folate Infuence Wnt, Beta-catenin, and Cadherin Pathways during Neural Tube Formation(Extended abstract)

2008 ◽  
Vol 22 (2) ◽  
pp. 119-121
Author(s):  
Yasuomi Nonaka ◽  
Yuzaburo Shimizu ◽  
Osamu Akiyama ◽  
Satoshi Tsutsumi ◽  
Yusuke Abe ◽  
...  
Keyword(s):  
Neural Tube ◽  
Tube Formation ◽  
Beta Catenin ◽  
Neural Tube Formation
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