The Experts below are selected from a list of 354 Experts worldwide ranked by ideXlab platform
Klaus Sander - One of the best experts on this subject based on the ideXlab platform.
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tribolium embryogenesis a sem study of cell shapes and movements from blastoderm to serosal closure
Development Genes and Evolution, 2000Co-Authors: Klaus Handel, Christoph G Grunfelder, Siegfried Roth, Klaus SanderAbstract:Embryogenesis in the beetle Tribolium is of increasing interest to both molecular and evolutionary biology because it differs from the Drosophila paradigm by its type of segment specification (short- vs. long-germ) and by the extensive ePithelial envelopes – amnion and serosa – that are typical of most insects but not of higher dipterans. Using scanning electron microscopy of DAPI staged embryos we document development in Tribolium castaneum from blastoderm to completion of the envelopes, recording many details not otherwise accessible; we also provide a time table of the respective stages at 30°C. The nascent blastoderm cells remain basally confluent with the yolksac until after the 13th (=last synchronous) mitotic cycle. The cells in the prospective serosa – the first domain to segregate visibly from the uniform blastoderm – carry surface protrusions likely to contact the overlying vitelline envelope. The embryonic rudiment, the other (and larger) blastodermal domain, gives rise to amnion and germ anlage. In the latter, visible differentiation begins with a ”Primitive Pit” reminiscent of the posterior midgut rudiment of Drosophila. The subsequent invagination of the mesoderm resembles Drosophila gastrulation, except in the head region where the median groove extends through the entire preoral region. The prospective amnion starts differing visibly from the germ anlage during early gastrulation. It then folds underneath the spreading serosa and, advancing with the latter, closes the amniotic cavity at the ventral face of the germband. The largest (=posterior) amniotic fold covers a crestlike protrusion of the yolksac. Together with marked changes in the shape and arrangement of the amnion cells, this protrusion may contribute to the fold’s elevation and early progress.
Klaus Handel - One of the best experts on this subject based on the ideXlab platform.
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tribolium embryogenesis a sem study of cell shapes and movements from blastoderm to serosal closure
Development Genes and Evolution, 2000Co-Authors: Klaus Handel, Christoph G Grunfelder, Siegfried Roth, Klaus SanderAbstract:Embryogenesis in the beetle Tribolium is of increasing interest to both molecular and evolutionary biology because it differs from the Drosophila paradigm by its type of segment specification (short- vs. long-germ) and by the extensive ePithelial envelopes – amnion and serosa – that are typical of most insects but not of higher dipterans. Using scanning electron microscopy of DAPI staged embryos we document development in Tribolium castaneum from blastoderm to completion of the envelopes, recording many details not otherwise accessible; we also provide a time table of the respective stages at 30°C. The nascent blastoderm cells remain basally confluent with the yolksac until after the 13th (=last synchronous) mitotic cycle. The cells in the prospective serosa – the first domain to segregate visibly from the uniform blastoderm – carry surface protrusions likely to contact the overlying vitelline envelope. The embryonic rudiment, the other (and larger) blastodermal domain, gives rise to amnion and germ anlage. In the latter, visible differentiation begins with a ”Primitive Pit” reminiscent of the posterior midgut rudiment of Drosophila. The subsequent invagination of the mesoderm resembles Drosophila gastrulation, except in the head region where the median groove extends through the entire preoral region. The prospective amnion starts differing visibly from the germ anlage during early gastrulation. It then folds underneath the spreading serosa and, advancing with the latter, closes the amniotic cavity at the ventral face of the germband. The largest (=posterior) amniotic fold covers a crestlike protrusion of the yolksac. Together with marked changes in the shape and arrangement of the amnion cells, this protrusion may contribute to the fold’s elevation and early progress.
Christoph G Grunfelder - One of the best experts on this subject based on the ideXlab platform.
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tribolium embryogenesis a sem study of cell shapes and movements from blastoderm to serosal closure
Development Genes and Evolution, 2000Co-Authors: Klaus Handel, Christoph G Grunfelder, Siegfried Roth, Klaus SanderAbstract:Embryogenesis in the beetle Tribolium is of increasing interest to both molecular and evolutionary biology because it differs from the Drosophila paradigm by its type of segment specification (short- vs. long-germ) and by the extensive ePithelial envelopes – amnion and serosa – that are typical of most insects but not of higher dipterans. Using scanning electron microscopy of DAPI staged embryos we document development in Tribolium castaneum from blastoderm to completion of the envelopes, recording many details not otherwise accessible; we also provide a time table of the respective stages at 30°C. The nascent blastoderm cells remain basally confluent with the yolksac until after the 13th (=last synchronous) mitotic cycle. The cells in the prospective serosa – the first domain to segregate visibly from the uniform blastoderm – carry surface protrusions likely to contact the overlying vitelline envelope. The embryonic rudiment, the other (and larger) blastodermal domain, gives rise to amnion and germ anlage. In the latter, visible differentiation begins with a ”Primitive Pit” reminiscent of the posterior midgut rudiment of Drosophila. The subsequent invagination of the mesoderm resembles Drosophila gastrulation, except in the head region where the median groove extends through the entire preoral region. The prospective amnion starts differing visibly from the germ anlage during early gastrulation. It then folds underneath the spreading serosa and, advancing with the latter, closes the amniotic cavity at the ventral face of the germband. The largest (=posterior) amniotic fold covers a crestlike protrusion of the yolksac. Together with marked changes in the shape and arrangement of the amnion cells, this protrusion may contribute to the fold’s elevation and early progress.
Siegfried Roth - One of the best experts on this subject based on the ideXlab platform.
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tribolium embryogenesis a sem study of cell shapes and movements from blastoderm to serosal closure
Development Genes and Evolution, 2000Co-Authors: Klaus Handel, Christoph G Grunfelder, Siegfried Roth, Klaus SanderAbstract:Embryogenesis in the beetle Tribolium is of increasing interest to both molecular and evolutionary biology because it differs from the Drosophila paradigm by its type of segment specification (short- vs. long-germ) and by the extensive ePithelial envelopes – amnion and serosa – that are typical of most insects but not of higher dipterans. Using scanning electron microscopy of DAPI staged embryos we document development in Tribolium castaneum from blastoderm to completion of the envelopes, recording many details not otherwise accessible; we also provide a time table of the respective stages at 30°C. The nascent blastoderm cells remain basally confluent with the yolksac until after the 13th (=last synchronous) mitotic cycle. The cells in the prospective serosa – the first domain to segregate visibly from the uniform blastoderm – carry surface protrusions likely to contact the overlying vitelline envelope. The embryonic rudiment, the other (and larger) blastodermal domain, gives rise to amnion and germ anlage. In the latter, visible differentiation begins with a ”Primitive Pit” reminiscent of the posterior midgut rudiment of Drosophila. The subsequent invagination of the mesoderm resembles Drosophila gastrulation, except in the head region where the median groove extends through the entire preoral region. The prospective amnion starts differing visibly from the germ anlage during early gastrulation. It then folds underneath the spreading serosa and, advancing with the latter, closes the amniotic cavity at the ventral face of the germband. The largest (=posterior) amniotic fold covers a crestlike protrusion of the yolksac. Together with marked changes in the shape and arrangement of the amnion cells, this protrusion may contribute to the fold’s elevation and early progress.
Kristen A. Panfilio - One of the best experts on this subject based on the ideXlab platform.
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Progression of serosal expression in the lines G12424 and KT650 across embryogenesis.
2014Co-Authors: Stefan Koelzer, Yvonne Kölsch, Kristen A. PanfilioAbstract:Live imaging detection of GFP in the transgenic Tribolium lines nGFP, G12424, and KT650. Micrographs labeled with the same letter are of a single embryo. Views are ventral (A1–A3), lateral (A4,B,C,E,F), or dorsal (D,G), with anterior left. (A–B) Exemplar nGFP embryos, illustrating the uniform blastoderm (BL), Primitive Pit (PP, white arrowhead), closing serosal window (SW), maximum germband extension (GBE), and mid serosal rupture (SR1) stages. Dashed lines label the serosal edge (A3,B) and posterior abdomen (A4). The embryo in panels A1–4 naturally rotated to a lateral view. (C–D) G12424 serosal EGFP increases from shortly after serosal window closure through mid germband retraction. (E–F1) KT650 serosal EGFP increases from shortly after maximum germband extension until just before serosal rupture. Both lines exhibit early EGFP expression in yolk globules (C1,E1: dashed outlines show embryo position, SW stage). The onset of serosal EGFP expression shows an anterior-dorsal or anterior bias (C2,E2: blue lines). During germband retraction, expression in both lines becomes dynamic, with streaks of EGFP between serosal nuclei (shown for G12424: compare C3′ and C4′, dots mark selected nuclei). (F2–G3) In both lines, serosal expression persists throughout the lifetime of the tissue (shown for KT650: sequential stages following serosal rupture, SR1-4, through tissue degeneration). Percentage values (C–F1) denote normalized EGFP intensity for each line. Time stamps show embryo minimum age (at 30°C). Anatomical abbreviations: H, head; S, serosa; T(x), thoracic segment (x). Scale bars are 100 µm, except for 50 µm in C3′. (H) Quantification of EGFP expression time courses, showing the mean ± standard deviation, with sample sizes indicated in the legend. Asterisks mark the maximum EGFP signal. Also plotted are the durations of the two films (younger, “y”; older, “o”: grey lines) and the morphological stages defined in Table 3 (black plot points). See Methods for details.