scholarly journals Molecular anatomy of the pre-primitive-streak chick embryo

Open Biology ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 190299 ◽  
Author(s):  
Hyung Chul Lee ◽  
Hui-Chun Lu ◽  
Mark Turmaine ◽  
Nidia M. M. Oliveira ◽  
Youwen Yang ◽  
...  
Keyword(s):  
Chick Embryo ◽  
Cell Polarity ◽  
Large Scale ◽  
Functional Anatomy ◽  
Primitive Streak ◽  
Vertebrate Species ◽  
History Of ◽  
Molecular Anatomy ◽  
Evolutionary Comparisons

The early stages of development of the chick embryo, leading to primitive streak formation (the start of gastrulation), have received renewed attention recently, especially for studies of the mechanisms of large-scale cell movements and those that position the primitive streak in the radial blastodisc. Over the long history of chick embryology, the terminology used to define different regions has been changing, making it difficult to relate studies to each other. To resolve this objectively requires precise definitions of the regions based on anatomical and functional criteria, along with a systematic molecular map that can be compared directly to the functional anatomy. Here, we undertake these tasks. We describe the characteristic cell morphologies (using scanning electron microscopy and immunocytochemistry for cell polarity markers) in different regions and at successive stages. RNAseq was performed for 12 regions of the blastodisc, from which a set of putative regional markers was selected. These were studied in detail by in situ hybridization. Together this provides a comprehensive resource allowing the community to define the regions unambiguously and objectively. In addition to helping with future experimental design and interpretation, this resource will also be useful for evolutionary comparisons between different vertebrate species.

scholarly journals Explaining the ocean's richest biodiversity hotspot and global patterns of fish diversity

2018 ◽  
Vol 285 (1888) ◽  
pp. 20181314 ◽  
Author(s):  
Elizabeth Christina Miller ◽  
Kenji T. Hayashi ◽  
Dongyuan Song ◽  
John J. Wiens
Keyword(s):  
Large Scale ◽  
Fish Diversity ◽  
Relative Importance ◽  
Diversification Rates ◽  
Marine Habitats ◽  
History Of ◽  
Richness Patterns ◽  
Colonization Time ◽  
Almost All

For most marine organisms, species richness peaks in the Central Indo-Pacific region and declines longitudinally, a striking pattern that remains poorly understood. Here, we used phylogenetic approaches to address the causes of richness patterns among global marine regions, comparing the relative importance of colonization time, number of colonization events, and diversification rates (speciation minus extinction). We estimated regional richness using distributional data for almost all percomorph fishes (17 435 species total, including approximately 72% of all marine fishes and approximately 33% of all freshwater fishes). The high diversity of the Central Indo-Pacific was explained by its colonization by many lineages 5.3–34 million years ago. These relatively old colonizations allowed more time for richness to build up through in situ diversification compared to other warm-marine regions. Surprisingly, diversification rates were decoupled from marine richness patterns, with clades in low-richness cold-marine habitats having the highest rates. Unlike marine richness, freshwater diversity was largely derived from a few ancient colonizations, coupled with high diversification rates. Our results are congruent with the geological history of the marine tropics, and thus may apply to many other organisms. Beyond marine biogeography, we add to the growing number of cases where colonization and time-for-speciation explain large-scale richness patterns instead of diversification rates.

scholarly journals Invasion of a basement membrane matrix by chick embryo primitive streak cells in vitro

1989 ◽  
Vol 92 (3) ◽  
pp. 497-504 ◽  
Author(s):  
E.J. Sanders ◽  
S. Prasad
Keyword(s):  
Chick Embryo ◽  
Basement Membrane ◽  
Primitive Streak ◽  
Lamina Densa ◽  
Invasive Potential ◽  
Tissue Space ◽  
Epithelial Sheet ◽  
Mesenchymal Transformation

At the time of gastrulation in the chick embryo the upper epiblast layer penetrates its own basement membrane at the primitive streak so that its cells may invade the underlying tissue space. In so forming the primary mesoderm, the cells undergo a concomitant epithelial-to-mesenchymal transformation. In this study, epiblast tissue has been explanted onto a basement membrane gel in order to examine its invasive potential. Fully ingressed primary mesoderm cells were able to penetrate the gel as individual cells, during the course of which the texture of the gel was disrupted. By contrast, epiblast tissue taken from the immediate vicinity of the primitive streak penetrated the gel, but only as a coherent tongue of cells and without gel disruption. These tongues of cells did not undergo the epithelial-to-mesenchymal transformation, and consequently spread as a epithelial sheet when replated on glass. Thus, the absence of gel disruption correlated with the failure of transformation, suggesting that these two events may be linked and that they may require in situ cell interactions for their manifestation. Tissue from the lateral epiblast failed to penetrate the gel. Instead, this tissue either spread on the gel surface or rounded up into a hollow sphere with the basal surface of the cells innermost. In the former case, despite the cell spreading, no lamina densa was organized beneath the sheet, but in the latter case polarity reversal occurred with the formation of a new lamina densa at the cell-gel interface.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Reconstruction of distinct vertebrate gastrulation modes via modulation of key cell behaviours in the chick embryo

2021 ◽  
Author(s):  
Manli Chuai ◽  
Guillermo Serrano Nájera ◽  
Mattia Serra ◽  
L. Mahadevan ◽  
Cornelis J. Weijer
Keyword(s):  
Chick Embryo ◽  
Teleost Fish ◽  
Primitive Streak ◽  
Theoretical Framework ◽  
Mesenchymal Cells ◽  
Signalling Pathways ◽  
Vertebrate Species ◽  
Self Organized ◽  
Cellular Behaviors ◽  
Epithelial Sheets

The morphology of gastrulation driving the internalisation of the mesoderm and endoderm differs dramatically among vertebrate species. It ranges from involution of epithelial sheets of cells through a circular blastopore in amphibians to ingression of mesenchymal cells through a primitive streak in amniotes. By targeting signalling pathways controlling critical cell behaviours in the chick embryo, we generated crescent- and ring-shaped mesendoderm territories in which cells can or cannot ingress. These alterations subvert the formation of the chick primitive streak into the gastrulation modes seen in amphibians, reptiles and teleost fish. Our experimental manipulations are supported by a theoretical framework linking cellular behaviors to self-organized multi-cellular flows in the accompanying paper. All together, this suggests that the evolution of gastrulation movements are largely determined by the shape of and cell behaviours in the mesendoderm territory across different species, and controlled by a relatively small number of signalling pathways.

Author response for "Molecular anatomy of the pre-primitive-streak chick embryo"

2020 ◽  
Author(s):  
Hyung Chul Lee ◽  
Hui-Chun Lu ◽  
Mark Turmaine ◽  
Nidia M. M. Oliveira ◽  
Youwen Yang ◽  
...  
Keyword(s):  
Chick Embryo ◽  
Primitive Streak ◽  
Author Response ◽  
Molecular Anatomy
Sign in / Sign up

Export Citation Format

Share Document