What Was Observed? (Introduction)

• Scientists focused on Xenopus embryos and tadpoles to understand head and face development, which provides insights into birth defects, evolution, and basic biology.
• Many existing resources were missing some crucial stages and views of Xenopus development, particularly for craniofacial (head and face) development.
• This gap in resources was addressed by creating 27 new, high-quality drawings that represent missing stages and views, aiming to make research more efficient and standardized.

What is Xenopus laevis? (Overview)

• Xenopus laevis is a species of frog widely used in scientific research, particularly for studying embryonic development and birth defects.
• Its embryos and tadpoles serve as models for understanding how bodies develop, regenerate, and evolve, making them important for fields like genetics, medicine, and neuroscience.

The Importance of the “Normal Table” (Previous Reference)

• In 1956, the “Normal Table of Xenopus laevis” was published, containing detailed illustrations of Xenopus development.
• These illustrations have been widely used in developmental biology to describe the stages of Xenopus from embryo to adult frog.
• However, some important stages were missing, especially in the context of craniofacial development, which is the focus of many modern studies.

Why New Illustrations Were Created? (Purpose)

• The new illustrations were made to fill in the gaps in the previous drawings, focusing on craniofacial development and stages not previously represented.
• These drawings were created to help scientists by providing a more complete visual reference for studying Xenopus embryos at various stages of development.

Planning the Illustrations (Process)

• Scientists consulted various researchers to decide which stages and views were most needed.
• Two criteria were used to select the views for the new illustrations:
  • Views that were missing from the previous “Normal Table”.
  • Views that illustrated significant changes during craniofacial development.
• Special attention was paid to show accurate details of changes in internal organs (like the optic lobe) and external features as the embryo developed.

Producing the Illustrations (Creation Process)

• The new illustrations were created based on live specimens observed under a microscope.
• To capture accurate features, embryos were carefully staged and observed, with any differences between individuals noted to ensure accuracy.
• Digital tools were used to create clean, modern versions of the drawings, starting with sketches and progressing to detailed digital images using Adobe Illustrator and Photoshop.
• The resulting illustrations aimed to maintain the same general style as previous drawings to allow easy comparison while also being distinct enough to credit the new artist.

Making the Zahn Drawings Available to the Community (Accessibility)

• The new illustrations by artist Natalya Zahn are made available to researchers through Xenbase, a database for Xenopus-related research.
• The drawings are freely available under a Creative Commons license, allowing non-commercial use with appropriate attribution.
• These drawings are grouped by the angle of view, showing the changes in Xenopus embryos over time, especially during critical stages of organ development.

What Do These New Drawings Show? (Key Insights)

• These new drawings reveal previously unstudied morphological changes in Xenopus embryos, particularly in the head region during organogenesis (the formation of organs).
• They provide a clearer understanding of how the shape and size of the head change during development, which was not as evident in the older drawings.
• These drawings also help confirm or challenge existing interpretations of the development process, encouraging new research questions.

Comparison with Earlier Drawings (Differences)

• The new drawings, made from live specimens, provide more accurate depictions of the embryos than older illustrations based on sketches.
• Earlier drawings, such as those by Prijs, were based on fixed specimens and did not account for biological variation in living embryos.
• In particular, the new illustrations help highlight the discrepancies noticed between the previous drawings and actual observations of the embryos, especially at certain stages.

Future Goals and Invitation for Further Drawings (Collaboration)

• The hope is that these new drawings will become as useful as the classic illustrations, supporting researchers in their work with Xenopus embryos.
• Researchers are encouraged to commission additional drawings of different stages or species, with the goal of creating a more complete library of reference materials for the scientific community.
• Anyone interested in commissioning new Xenopus drawings is invited to work with Natalya Zahn and to consider sharing their images on Xenbase for open access to the broader community.

观察到什么？ (引言)

• 科学家们关注了非洲爪蛙 (Xenopus) 胚胎和蝌蚪的发育，特别是头部和面部的发育，这为了解出生缺陷的原因、进化和基本生物学提供了新颖且关键的见解。
• 许多现有的资源缺少一些关键的阶段和视角，尤其是在颅面发育的研究中。
• 为了填补这一空白，科学家们创造了27幅新的高质量插图，代表了缺失的阶段和视角，目的是使研究更高效和标准化。

什么是非洲爪蛙 (Xenopus laevis)？ (概述)

• 非洲爪蛙是一种广泛用于科学研究的青蛙，特别是在胚胎发育和出生缺陷的研究中。
• 它的胚胎和蝌蚪是研究身体如何发育、再生和进化的重要模型，因此在遗传学、医学和神经科学等领域非常重要。

《正常表格》的重要性 (之前的参考资料)

• 1956年，《正常表格》出版，包含了非洲爪蛙发育的详细插图。
• 这些插图广泛用于发育生物学，用于描述非洲爪蛙从胚胎到成年青蛙的各个阶段。
• 然而，某些重要的阶段缺失，尤其是在颅面发育的背景下，这是当代研究的重点。

为什么需要新的插图？ (目的)

• 新的插图是为了填补《正常表格》中缺失的部分，重点是颅面发育和未曾表现的阶段。
• 这些插图帮助科学家提供更完整的视觉参考，用于研究不同阶段的非洲爪蛙胚胎。

插图规划 (过程)

• 科学家们与多位研究人员沟通，决定哪些阶段和视角最为需要。
• 选择插图时采用了两个标准：
  • 《正常表格》中缺失的视角。
  • 有助于展示颅面发育过程中显著变化的视角。
• 特别关注了在胚胎发育过程中内脏器官（如视网膜）和外部特征的变化。

插图制作 (创作过程)

• 新的插图基于显微镜下观察的活体样本创作。
• 通过小心地为胚胎定期分期和观察，确保了插图的准确性。
• 使用数字工具创作干净、现代化的插图，从草图开始，逐步制作出详细的数字图像。
• 结果是这些插图保持与以前插图相似的风格，以便比较，并且具有独特的辨识度，确保了新艺术家的署名。

将Zahn插图提供给社区 (开放访问)

• 由艺术家Natalya Zahn创作的插图通过Xenbase数据库提供给研究人员。
• 这些插图在Creative Commons许可证下免费提供，允许非商业使用并需适当署名。
• 这些插图按视角分组，展示了非洲爪蛙胚胎在关键发育阶段中的变化。

这些新插图展示了什么？ (关键见解)

• 这些新插图揭示了非洲爪蛙胚胎在器官发生（器官形成）期间尚未研究的形态变化，特别是头部区域。
• 它们为我们提供了更清晰的理解，展示了在发育过程中头部形状和大小的变化，这是以前的插图中所未能展现的。
• 这些插图还帮助确认或挑战现有的发育过程解释，激发新的研究问题。

与早期插图的对比 (差异)

• 这些新插图是基于活体样本创作的，提供比早期基于草图创作的插图更准确的胚胎表现。
• 早期的插图，如Prijs的插图，是基于固定的样本创作的，并未考虑到活体胚胎的生物学变异。
• 尤其在某些阶段，这些新插图帮助凸显了早期插图与实际观察之间的差异。

未来目标与进一步绘图邀请 (合作)

• 希望这些新插图能像经典插图一样为科学家们提供帮助，支持他们在非洲爪蛙胚胎研究中的工作。
• 研究人员被鼓励委托绘制不同阶段或物种的更多插图，目标是创建一个更完整的参考资料库供科学社区使用。
• 任何有兴趣委托新的非洲爪蛙插图的人都可以与Natalya Zahn合作，并考虑将其图像上传到Xenbase，供更广泛的社区共享。