Normal Table of Xenopus development: a new graphical resource

Abstract

Normal tables of development are essential for studies of embryogenesis, serving as an important resource for model organisms, including the frog Xenopus laevis. Xenopus has long been used to study developmental and cell biology, and is an increasingly important model for human birth defects and disease, genomics, proteomics and toxicology. Scientists utilize Nieuwkoop and Faber's classic ‘Normal Table of Xenopus laevis (Daudin)’ and accompanying illustrations to enable experimental reproducibility and reuse the illustrations in new publications and teaching. However, it is no longer possible to obtain permission for these copyrighted illustrations. We present 133 new, high-quality illustrations of X. laevis development from fertilization to metamorphosis, with additional views that were not available in the original collection. All the images are available on Xenbase, the Xenopus knowledgebase (http://www.xenbase.org/entry/zahn.do), for download and reuse under an attributable, non-commercial creative commons license. Additionally, we have compiled a ‘Landmarks Table’ of key morphological features and marker gene expression that can be used to distinguish stages quickly and reliably (https://www.xenbase.org/entry/landmarks-table.do). This new open-access resource will facilitate Xenopus research and teaching in the decades to come.

Membrane potential drives the exit from pluripotency and cell fate commitment via calcium and mTOR

“…In line with the previous electrophysiological evidence demonstrating that embryos first become polarized at the blastula stage 16 , we found that Barium treatment affected embryonic development primarily when embryos were treated from blastula stages through gastrulation rather than at earlier cleavage stages (Fig. 1b, c, f, g, j-l) 17 . Embryonic development was affected in two ways: (1) 37 ± 3% (SEM) of the embryos failed to complete gastrulation (compared to just 4.7 ± 1% in control embryos) (Fig.…”

Development of subdomains in the medial pallium of Xenopus laevis and Trachemys scripta: Insights into the anamniote-amniote transition

“…This timing is very interesting from a functional point of view. We lack data on the behavior of developing turtles, but in Xenopus laevis, in embryos between stages 32 and 37/38, in which, based on our data, the MP expansion has not yet begun [ (Moreno and González, 2017); present results], simple mechanisms derived from contact reflexes (non-vestibular), mediate the orientation of scape swimming response (Roberts et al, 2000), such this behavioral response begins to be seen at this point in development (Zahn et al, 2022). Therefore, the functional/behavioral capabilities of this model, attributed to the MP (see above), could (i) start to operate at later stages of development, or (ii) it could be the additional territories, already specified at these stages, functionally involved in this task, or (iii) even with the MP at a low degree of development, it could already be involved in these functions.…”

Xenbase: key features and resources of the Xenopus model organism knowledgebase

“…To resolve this situation, Xenbase commissioned a new set of open-access drawings of Xenopus embryos to generate a new comprehensive suite of reference images not only covering those in the Nieuwkoop and Faber images but also expanding the representation to include additional views and stages missed in the original resource ( Zahn et al 2022 ). These new images complement those generated by Zahn et al ( 2017 ) that initiated this project with a set of drawings focused on stages and orientations relevant to craniofacial development. The new set comprises 133 high-quality illustrations spanning from fertilization to post-metamorphosis, all available under a noncommercial creative commons license and freely usable by the research community.…”