scholarly journals Greb1 is required for axial elongation and segmentation in vertebrate embryos

Biology Open ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. bio047290
Author(s):  
Ravindra Singh Prajapati ◽  
Richard Mitter ◽  
Annalisa Vezzaro ◽  
David Ish-Horowicz
Keyword(s):  
Axial Elongation ◽  
Vertebrate Embryos

scholarly journals Greb1 is required for axial elongation and segmentation in vertebrate embryos

2019 ◽  
Author(s):  
Ravindra Singh Prajapati ◽  
Richard Mitter ◽  
Annalisa Vezzaro ◽  
David Ish-Horowicz
Keyword(s):  
Estrogen Receptor ◽  
Embryonic Development ◽  
Clock Gene ◽  
Zebrafish Embryos ◽  
Presomitic Mesoderm ◽  
Axial Elongation ◽  
No Tail ◽  
Vertebrate Embryos ◽  
Progenitor Maintenance ◽  
Segmentation Clock Gene

ABSTRACTDuring vertebrate embryonic development, the formation of axial structures is driven by a population of stem-like cells that reside in a region of the tailbud called the chordoneural hinge (CNH). We have compared the CNH transcriptome with those of surrounding tissues and shown that the CNH and tailbud mesoderm are transcriptionally similar, and distinct from the presomitic mesoderm. Amongst CNH-enriched genes are several that are required for axial elongation, including Wnt3a, Cdx2, Brachyury/T and Fgf8, and androgen/estrogen receptor nuclear signalling components such as Greb1. We show that the pattern and duration of tailbud Greb1 expression is conserved in mouse, zebrafish, and chicken embryos, and that Greb1 is required for axial elongation and somitogenesis in zebrafish embryos. The axial truncation phenotype of Greb1 morphant embryos is explained by much reduced expression of No tail (Ntl/Brachyury) which is required for axial progenitor maintenance. Posterior segmentation defects in the morphants (including misexpression of genes such as mespb, myoD and papC) appear to result, in part, from lost expression of the segmentation clock gene, her7.

scholarly journals Modular crawling robots using soft pneumatic actuators

2020 ◽  
Author(s):  
Nianfeng Wang ◽  
Bicheng Chen ◽  
Xiandong Ge ◽  
Xianmin Zhang ◽  
Wenbin Wang
Keyword(s):  
3D Printing ◽  
Numerical Models ◽  
Pneumatic Actuators ◽  
Axial Elongation ◽  
Control Schemes ◽  
Good Agreement

AbstractCrawling robots have elicited much attention in recent years due to their stable and efficient locomotion. In this work, several crawling robots are developed using two types of soft pneumatic actuators (SPAs), namely, an axial elongation SPA and a dual bending SPA. By constraining the deformation of the elastomeric chamber, the SPAs realize their prescribed motions, and the deformations subjected to pressures are characterized with numerical models. Experiments are performed for verification, and the results show good agreement. The SPAs are fabricated by casting and developed into crawling robots with 3D-printing connectors. Control schemes are presented, and crawling tests are performed. The speeds predicted by the numerical models agree well with the speeds in the experiments.

The effect of 0.01% atropine on ocular axial elongation for myopia children: a meta-analysis

2021 ◽  
Author(s):  
Yan Yu ◽  
Jiasu Liu
Keyword(s):  
Publication Bias ◽  
Meta Analysis ◽  
Statistical Significance ◽  
Cochrane Library ◽  
Axial Elongation ◽  
Funnel Plots ◽  
Mean Differences ◽  
Q Statistic ◽  
Regression Tests ◽  
Review Manager

Objectives: This meta-analysis aimed to identify the therapeutic effect of 0.01% atropine with on ocular axial elongation for myopia children. Methods: We searched PubMed, Cochrane Library, and CBM databases from inception to July 2021. Meta-analysis was conducted using STATA version 14.0 and Review Manager version 5.3 softwares. We calculated the weighted mean differences(WMD) to analyze the change of ocular axial length (AL) between orthokeratology combined with 0.01% atropine (OKA) and orthokeratology (OA) alone. The Cochran's Q-statistic and I2 test were used to evaluate potential heterogeneity between studies. To evaluate the influence of single studies on the overall estimate, a sensitivity analysis was performed. We also performed sub group and meta-regression analyses to investigate potential sources of heterogeneity. We conducted Begger's funnel plots and Egger's linear regression tests to investigate publication bias. Results: Nine studies that met all inclusion criteria were included in this meta-analysis. A total of 191 children in OKA group and 196 children in OK group were assessed. The pooled summary WMD of AL change was -0.90(95%CI=-1.25~-0.55) with statistical significance(t=-5.03, p<0.01), which indicated there was obvious difference between OKA and OK in myopic children. Subgroup analysis also showed that OKA treatment resulted in significantly less axial elongation compared to OK treatment alone according to SER. We found no evidence for publication bias. Conclusions:  Our meta-analysis indicates 0.01% atropine atropine is effective in slowing axial elongation in myopia children with orthokeratology.

Interruption of cardiac output does not affect short-term growth and metabolic rate in day 3 and 4 chick embryos

2000 ◽  
Vol 203 (24) ◽  
pp. 3831-3838 ◽  
Author(s):  
W.W. Burggren ◽  
S.J. Warburton ◽  
M.D. Slivkoff
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Body Mass ◽  
Regression Line ◽  
Heart Beat ◽  
Chick Embryos ◽  
Simple Diffusion ◽  
Significant Difference ◽  
Vertebrate Embryos ◽  
Cervical Flexure

The heart beat of vertebrate embryos has been assumed to begin when convective bulk transport by blood takes over from transport by simple diffusion. To test this hypothesis, we measured eye growth, cervical flexure and rates of oxygen consumption (V(O2)) in day 3–4 chick embryos denied cardiac output by ligation of the outflow tract and compared them with those of embryos with an intact cardiovascular system.Eye diameter, used as the index for embryonic growth, increased at a rate of approximately 4.5-5 % h(−)(1) during the observation period. There was no significant difference (P&gt;0.1) in the rate of increase in eye diameter between control (egg opened), sham-ligated (ligature present but not tied) and ligated embryos. Similarly, the normal progression of cervical flexure was not significantly altered by ligation (P&gt;0.1). V(O2) (ml O(2)g(−)(1)h(−)(1)) at 38 degrees C, measured by closed respirometry, was not significantly different (P&gt;0.1) on day 3 in sham-ligated (14.5+/−1.9 ml O(2)g(−)(1)h(−)(1)) and ligated 17.6+/−1.8 ml O(2)g(−)(1)h(−)(1)) embryos. Similarly, on day 4, V(O2) in sham-ligated and ligated embryos was statistically the same (sham-ligated 10. 5+/−2.9 ml O(2)g(−)(1)h(−)(1); ligated 9.7+/−2.9 ml O(2)g(−)(1)h(−)(1)). Expressed as a linear function of body mass (M), V(O2) in sham-ligated embryos was described by the equation V(O2)=−0.48M+24.06 (r(2)=0.36, N=18, P&lt;0.01), while V(O2) in ligated embryos was described by the equation V(O2)=−0.53M+23.32 (r(2)=0.38, N=16, P&lt;0.01). The regression line describing the relationship between body mass and V(O2) for pooled sham-ligated and ligated embryos (the two populations being statistically identical) was V(O2)=−0.47M+23.24. The slope of this regression line, which was significantly different from zero (r(2)=0.30, N=34, P&lt;0.01), was similar to slopes calculated from previous studies over the same range of body mass.Collectively, these data indicate that growth and V(O2) are not dependent upon cardiac output and the convective blood flow it generates. Thus, early chick embryos join those of the zebrafish, clawed frog and axolotl in developing a heart beat and blood flow hours or days before required for convective oxygen and nutrient transport. We speculate that angiogenesis is the most likely role for the early development of a heart beat in vertebrate embryos.

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