The shingled girl: Catherine Janet Hill and her contributions to embryology.

Catherine J. Hill is best remembered for her dedication to cataloguing the comprehensive embryological collection of her father J. P. Hill. Yet, her own research, during the interwar years, is little known. She made a significant contribution to interpreting the autonomic innervation of the gut, work that was presented to The Royal Society and earned her a PhD. Working in her father's laboratory, she then set about solving the sequence of secretions from the tubal epithelium and uterine glands that contributed the two layers of egg albumen and three shell layers of the monotreme egg. She was also the first to understand twinning in the marmoset and how two embryos came to share a single extraembryonic coelom, work that often is credited to J. P. Hill. Here. I explain how that happened and explore the context in which she and other female scientists worked at the time.

Ian Wilmut (1944-2023).

Embryologist who cloned Dolly the sheep.

The people behind the papers - Masaki Kinoshita, Toshihiro Kobayashi, Hiroshi Nagashima, Ramiro Alberio and Austin Smith.

The ability to derive and maintain pluripotent stem cells (PSCs) from livestock species in defined media conditions will contribute to many new research avenues, including comparative embryology and xenotransplantation. In a new paper in Development, Masaki Kinoshita, Toshihiro Kobayashi, Hiroshi Nagashima, Ramiro Alberio, Austin Smith and colleagues describe their three-component medium, which supports long-term propagation of PSCs in the absence of feeders or serum factors. We caught up with the authors to find out more about their research and their future plans.

The Biography of Specimen "09.04.1954, 3.4 mm" from the "Blechschmidt Collection of Human Embryos" at Göttingen University with a Special Focus on the Production and Usage of Enlarged 3D Replicas of Embryos in the Anatomical Research on Human Embryos.

The "Blechschmidt Collection of Human Embryos" housed at the Anatomical Institute of Göttingen University (Germany) is an important historical collection of human embryo specimens whose history dates back up to the mid-1940s. It is named after its founder Prof. Erich Blechschmidt (1904-1992). A 2-year research project was conducted from 2017 to 2019 with the aim of clarifying the provenience of the human embryo specimens collected by Blechschmidt. This project not only has provided information on the origin of the specimens but, additionally, led to the discovery of photographic documents illustrating the process by which Blechschmidt built the enlarged 3-dimensional replicas of human embryos that are shown in a dedicated exhibition hall in the basement of the Anatomical Institute. Here, we report on an embryo from the Blechschmidt collection whose biography as a microscopical specimen as well as a source for objects of Blechschmidt's collection of 3-dimensional replicas of human embryos is documented by letters, lab-books, and photographs. Our report is complemented by a short historical review on the production and usage of enlarged 3-dimensional replicas in research on the anatomy of human embryo.

Aristotle, Buddhist scripture and embryology in ancient Mexico: building inclusion by re-thinking what counts as the history of developmental biology.

It has not gone unnoticed in recent times that historical writing about science is heavily Eurocentric. A striking example can be found in the history of developmental biology: textbooks and popular science writing frequently trace an intellectual thread from the Greek philosopher Aristotle through 19th century embryology to 20th century genetics. Few in our field are aware of the depth and breadth of early embryological thinking outside of Europe. Here, I provide a series of vignettes highlighting the rich history of embryological thinking in Asia and Latin America. My goal is to provide an entertaining, even provocative, synopsis of this important but under-studied topic. It is my hope that this work will spur others to carry out more thorough investigations, with the ultimate goal of building a more inclusive discipline.

[The saga of neural induction: almost a century of research]. / La saga de l'induction neurale : presque un siècle de recherche.

Neural induction is a developmental process that allows cells from the ectoderm (the target tissue) to acquire a neural fate in response to signals coming from a specific adjacent embryonic region, the dorsal mesoderm (the inducing tissue). This process described in 1924 in amphibian embryos has not received a molecular explanation until the mid-1990s. Most of the work on neural induction has been carried out in amphibians. At these times, although the role played by the membrane of the target tissue had been suggested, no definitive work had been performed on the transduction of the neuralizing signal. Between 1990 and 2019 our aim was to decipher this transduction. We have underlined the necessary and sufficient role played by calcium signaling to induce ectoderm cells towards a neural fate from the activation of calcium channels to the direct transcription of early neural genes by calcium.

TITLE: La saga de l'induction neurale : presque un siècle de recherche. ABSTRACT: La formation du système nerveux débute par l'induction neurale, un processus qui permet aux cellules de l'ectoderme (tissu cible) d'acquérir un destin neural en réponse à des signaux provenant du mésoderme dorsal (tissu inducteur). Ce processus, décrit en 1924 sur l'amphibien, n'a reçu une explication moléculaire qu'au milieu des années 1990. Pendant cette période, plusieurs auteurs se sont intéressés au rôle joué par la membrane du tissu cible mais peu de travaux décisifs ont décrit la transduction du signal neuralisant. Entre 1990 et 2019, nous avons disséqué la transduction du signal neuralisant, un sujet très peu abordé alors. Nous avons souligné le rôle nécessaire et suffisant du calcium pour orienter les cellules de l'ectoderme vers un destin neural et établi la cascade moléculaire allant de l'activation de canaux membranaires à la transcription de gènes.

[Modelled Development. Practices of Human Embryology at Göttingen University in the Second Half of the Twentieth Century]. / Modellierte Individualentwicklung. Humanembryologische Praktiken an der Universität Göttingen in der zweiten Hälfte des 20. Jahrhunderts.

The Human Embryology Collection at the Centre of Anatomy Göttingen, created between 1942 and 1970, represents a unique interrelation of histological sectional series of human embryos and large-format physical models open to the public based on them. The collection was established long after the heyday of human embryology. It is also remarkable in another aspect: while usually models within the discipline are considered research objects, Göttingen embryologist Erich Blechschmidt (1904-1992) based his understanding on a pedagogical impetus. The article highlights the distinctive and unconventional features of Blechschmidt's undertaking against its disciplinary background. My focus lies on the two practices that are central to human embryology-collecting and modelling-, as well as the derived collection stocks. The special tension between individuality and universality that already characterized the process of their creation is also reflected in the later use of the collection. This tension allowed Blechschmidt to utilize the models in embryological research and anatomical teaching as well as in the broad social debate on abortion and the ethical status of human embryos.

Localized translation on the mitotic apparatus: A history and perspective.

Localized translation is a proposed biological event that allows mRNA to be translated on site, providing an additional level of protein regulation within a cell. Examples of localized translation have been found or proposed in a variety of cellular contexts from neurons to cancer cells and implicated in both normal development and disease for over a half century. For example, mRNA translation on the mitotic apparatus (MA) was initially hypothesized in the 1950-60s. However, its proof of existence, biological significance and mechanistic details have remained sparse and it is still unclear how well conserved this mechanism may be among different cell types or organisms. In this review, we provide a brief historic summary of translation on the MA and discuss how current and future work may help us understand this biological process that provides a subcellular level of regulation in protein synthesis within a cell.

An interview with Celina Juliano.

Celina Juliano is an Assistant Professor at UC Davis, where she uses Hydra as a model system to understand development and regeneration. She is co-founder of the Cnidarian Model Systems Meeting (Cnidofest) biennial conference and the OpenHydra Hydra resource platform. This year, she was awarded the Elizabeth D. Hay New Investigator award for outstanding developmental biology research during the early stages of her independent career by the Society for Developmental Biology (SDB). Following the virtual SDB 2020 meeting, we met with Celina over Zoom to hear more about her life and career.

The people behind the papers - Kayt Scott and Bruce Appel.

In the developing spinal cord, progenitor cells sequentially give rise to motor neurons and precursors of one of the major glial cell types: oligodendrocytes. A new paper in Development unpicks the molecular control of the neuron-glia switch and the differentiation of oligodendrocyte precursors in the zebrafish embryo. To find out more about the work, we met first author and graduate student Kayt Scott and her supervisor Bruce Appel, who holds the Diane G. Wallach Chair of Pediatric Stem Cell Biology and is Professor and Head of the Section of Developmental Biology at the Department of Pediatrics, University of Colorado School of Medicine in Aurora.

Fields, patterns and information: R.L. Brahmachary's contributions during the infancy of molecular embryology.

The contribution of Professor Ratan Lal Brahmachary's research during the early years of molecular embryology, its theoretical underpinnings, and its connection with those of other contemporary research efforts, are traced in this article as a part of the history of developmental biology research in India.

Publicity, politics, and professoriate in fin-de-siècle Vienna: The misconduct of the embryologist Samuel Leopold Schenk.

This essay uses the case of the fin-de-siècle Vienna embryologist Samuel Leopold Schenk to analyze the factors at play in allegations of misconduct. In 1898, Schenk published a book titled Theorie Schenk. Einfluss auf das Geschlechtsverhältnis (Schenk's theory. Influence on the sex ratio). The book argued that, by changing their diet, women trying to conceive could influence egg maturation and consequently select the sex of their offspring. This cross between a scientific monograph and a popular advice book received enormous publicity but also spurred first the Vienna Medical Association and then the Senate of the University of Vienna to accuse Schenk of poor science, self-advertisement, quack medical practice, and wrong publisher choice. Formal proceedings against Schenk ended in 1900 with the unusually harsh punishment of early retirement. Schenk died two years later. I examine the elements of the case, from the science of sex determination and selection, to the growth of print media and advertising within the changing demographic and political landscape of Vienna. I argue that the influence of the public, via the growing media, upon science was the main driver of the case against Schenk, but also that the case would have had a more limited impact were it not for the volatile political moment rife with anti-Semitism, nationalism, and xenophobia. I draw the attention to the importance of setting cases of misconduct in the broader political history and against the key social concerns of the moment.

The people behind the papers - Charles Sheehan, John McMahon and Debby Silver.

Interneurons are crucial to cortical function and their dysregulation has been implicated in various neurological pathologies, yet how they are generated during development is still poorly understood. A new paper in Development investigates interneuron neurogenesis in the mouse embryo and its control by Magoh, a component of the exon junction complex. We heard more about the work from the paper's two first authors, Charles Sheehan and John McMahon, and their supervisor Debby Silver, Associate Professor at Duke University Medical Center in Durham, North Carolina.

The people behind the papers - Xin Zhu, Yiquan Wang and Guang Li.

During development, the establishment of directional left-right (L-R) asymmetry is crucial for the correct positioning of organs within the body. How symmetry is broken in the embryo is still incompletely understood at the molecular level, as is its evolutionary history. A new paper in Development tackles this problem with an analysis of L-R asymmetry in the basal chordate amphioxus. We caught up with first author Xin Zhu and supervisors Yiquan Wang and Guang Li of Xiamen University in Fujian, China, to find out more about the work.

An interview with Maria Elena Torres-Padilla.

Maria Elena Torres-Padilla is Director of the Institute of Epigenetics and Stem Cells at Helmholtz Zentrum München, Germany. Maria Elena, who studies how cell potency and cell fate are regulated by chromatin-mediated processes, was recently appointed as an Academic Editor at Development. We caught up with Maria Elena at a recent conference to find out more about her background, her research and her thoughts on the ties between the chromatin and developmental biology fields.