Cell Numbers in the Gut of the Embryo of the Sea Urchin Hemicentrotus pulcherrimus

Mizoguchi, Hazime

doi:10.2108/zsj.16.341

Cited by 6 publications

(16 citation statements)

References 11 publications

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“…The following assumptions were made: 1) each cell was represented by 16 particles with radii (r) of 1.125 µm, and each embryo was represented by 64 cells connected in a ring (Fig. S7); 2) each cell perimeter was 36 µm and the height and width of the embryo at step 1 were 110 and 100 µm, respectively, which was consistent with sea urchin embryo observations (results not shown); 3) the number of cells was constant because cell divisions and cell invasions from other cross-sections were rarely observed during the primary invagination stage [33]; 4) the motion of each particle obeyed the overdamped limit of the equation (1) of motion,…”

Section: Mathematical Model Of Sea Urchin Embryossupporting

confidence: 83%

“…5a). III) Cell divisions and three-dimensional mutual cell invasions mainly contributing to late gastrulation were not included because these processes were rarely observed in early gastrulation [33]. Therefore, the present model described embryo shape dynamics of the control and inhibited embryos introducing two-dimensional motions and deformations of the apical and basal sides in 64 cells (Fig.…”

Section: Mathematical Model Of Embryonic Shape Formations In Early Gastrulation Considering Cell-dependent F-actin Polaritymentioning

confidence: 99%

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H+/K+ Ion Pump Enhances Cytoskeletal Polarity to Drive Gastrulation in Sea Urchin Embryo

Watanabe

Yasui

Kurose

et al. 2021

Preprint

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Gastrulation is a universal process in the morphogenesis of many animal embryos. In sea urchin embryos, it involves the invagination of a single-layered vegetal plate into the blastocoel. Although morphological and molecular events in gastrulation have been well studied, the mechanical driving forces and the regulatory mechanism underlying gastrulation is not fully understood. In this study, structural features and cytoskeletal distributions were studied in sea urchin embryos using an “exogastrulation” model induced by inhibiting the H+/K+ ion pump with omeprazole. The vegetal poles of the exogastrulating embryos showed reduced roundness indices, intracellular pH polarization, and intracellular F-actin polarization at the pre-early gastrulation stage compared with normal embryos. Gastrulation stopped when F-actin polymerization or degradation was inhibited via RhoA or YAP1 knockout, although pH distributions were independent of such a knockout. A mathematical model of sea urchin embryos at the early gastrulation reproduced the shapes of both normal and exogastrulating embryos using cell-dependent cytoskeletal features based on F-actin and pH distributions. Thus, gastrulation required appropriate cell position-dependent intracellular F-actin distributions regulated by the H+/K+ ion pump through pH control.

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Section: Mathematical Model Of Sea Urchin Embryossupporting

confidence: 83%

Section: Mathematical Model Of Embryonic Shape Formations In Early Gastrulation Considering Cell-dependent F-actin Polaritymentioning

confidence: 99%

H+/K+ Ion Pump Enhances Cytoskeletal Polarity to Drive Gastrulation in Sea Urchin Embryo

Watanabe

Yasui

Kurose

et al. 2021

Preprint

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“…This difference has influenced scientists to study a more experimentally accessible target. In addition, later stage embryos have more cells (Mizoguchi ), and there are fewer neural cells than endomesodermal cells, making it difficult to collect material such as RNA or protein specifically from the neural cells. To overcome these disadvantages, although the ratio of neural cell number may be invariable within each species of sea urchin, we sought to establish a new model urchin with faster growth during embryogenesis.…”

Section: Introductionmentioning

confidence: 99%

Early development and neurogenesis of Temnopleurus reevesii

et al. 2015

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Sea urchins are model non-chordate deuterostomes, and studying the nervous system of their embryos can aid in the understanding of the universal mechanisms of neurogenesis. However, despite the long history of sea urchin embryology research, the molecular mechanisms of their neurogenesis have not been well investigated, in part because neurons appear relatively late during embryogenesis. In this study, we used the species Temnopleurus reevesii as a new sea urchin model and investigated the detail of its development and neurogenesis during early embryogenesis. We found that the embryos of T. reevesii were tolerant of high temperatures and could be cultured successfully at 15-30°C during early embryogenesis. At 30°C, the embryos developed rapidly enough that the neurons appeared at just after 24 h. This is faster than the development of other model urchins, such as Hemicentrotus pulcherrimus or Strongylocentrotus purpuratus. In addition, the body of the embryo was highly transparent, allowing the details of the neural network to be easily captured by ordinary epifluorescent and confocal microscopy without any additional treatments. Because of its rapid development and high transparency during embryogenesis, T. reevesii may be a suitable sea urchin model for studying neurogenesis. Moreover, the males and females are easily distinguishable, and the style of early cleavages is intriguingly unusual, suggesting that this sea urchin might be a good candidate for addressing not only neurology but also cell and developmental biology.

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“…2) Each cell perimeter was 36 μm and the height and width of the embryo at step 1 was 110 μm and 100 μm, respectively, which was consistent with sea urchin embryo observations (results not shown). 3) The number of cells was constant because cell divisions and cell invasions from other cross-sections were rarely observed during the primary invagination stage (Mizoguchi, 1999). 4) The motion of each particle obeyed the following overdamped limit of the equation of motion: where X i , j = ( x i,j ( t ), y i,j ( t )) is the position of the j -th particle constructing the i -th cell ( i = 0,1,2…63 and j = 0,1,2…15) on the x‒y plane at time t (Fig.…”

Section: Methodsmentioning

confidence: 99%

Partial exogastrulation due to apical-basal polarity of F-actin distribution disruption in sea urchin embryo by omeprazole

Watanabe

Yasui

Kurose

et al. 2021

Preprint

View full text Add to dashboard Cite

Gastrulation is a universal process in the morphogenesis of many animal embryos. In sea urchin embryos, it involves the invagination of single-layered vegetal plate into blastocoel. Although morphological and molecular events have been well studied for gastrulation, the mechanical driving forces and their regulatory mechanism underlying the gastrulation is not fully understood. In this study, structural features and cytoskeletal distributions were studied in sea urchin embryo using an "exogastrulation" model induced by inhibiting the H+/K+ ion pump with omeprazole. The vegetal pole sides of the exogastrulating embryos had reduced roundness indices, intracellular pH polarization, and intracellular F-actin polarization at the pre-early gastrulation compared with the normal embryo. Gastrulation stopped when F-actin polymerization or degradation was inhibited by RhoA or YAP1 knockout, although pH distributions were independent of such a knockout. A mathematical model of sea urchin embryos at the early gastrulation reproduced the shapes of both normal and exogastrulating embryos using cell-dependent cytoskeletal features based on F-actin and pH distributions. Thus, gastrulation required appropriate cell position-dependent intracellular F-actin distributions regulated by the H+/K+ ion pump through pH control.

show abstract

Cell Numbers in the Gut of the Embryo of the Sea Urchin Hemicentrotus pulcherrimus

Cited by 6 publications

References 11 publications

H+/K+ Ion Pump Enhances Cytoskeletal Polarity to Drive Gastrulation in Sea Urchin Embryo

H+/K+ Ion Pump Enhances Cytoskeletal Polarity to Drive Gastrulation in Sea Urchin Embryo

Early development and neurogenesis of Temnopleurus reevesii

Partial exogastrulation due to apical-basal polarity of F-actin distribution disruption in sea urchin embryo by omeprazole

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