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Title: | 水生環節動物Monopylephrous sp.的前端再生過程與胚胎發育 Characterization of the anterior regeneration and embryogenesis of the aquatic annelid Monopylephrous sp. |
Authors: | Yu-Chia Kuo 郭又嘉 |
Advisor: | 郭典翰(Dian-Han Kuo) |
Co-Advisor: | 游智凱(Jr-Kai Yu) |
Keyword: | 再生,環節動物,胚基,長出物,細胞增生,演化, regeneration,annelid,blastema,outgrowth,cell proliferation,evolution, |
Publication Year : | 2020 |
Degree: | 碩士 |
Abstract: | 再生在動物界裡是很常見的現象,但不同物種間的再生能力有很大的差異。相對於無脊椎動物,脊椎動物的再生,局限在組織或器官的層次上,而無脊椎動物像是渦蟲還有環節動物,則具有從身體的部分片段,再生回完整個體的能力。因為這樣驚人的再生能力,目前關於渦蟲的再生已有相當深入的研究,然而關於其他無脊椎動物的再生,研究還是相當不足。我希望能藉由研究環節動物再生的過程,來了解再生這個現象在不同物種間有何差異?又是如何演化的?其中有幾個我感興趣的問題,第一個問題是:環節動物再生最初始時,在細胞的層次上,發生了怎樣的事件?第二個問題是:環節動物的胚基(blastema)是如何形成的?是像渦蟲一樣透過體內未分化的幹細胞分化形成胚基,又或是透過去分化的過程形成未分化的狀態再形成胚基?為了回答這些問題,我發展出了一種新的實驗動物Monopylephrous,Monopylephrous是一種大型的水生貧毛類,具有良好的再生能力,能在十五天內再生回完整的頭部,此外因為Monopylephrous透明的身體和容易取得的胚胎,讓牠在利用基因轉殖技術標記並追蹤細胞上極具發展潛力,也能利用分子標記、確認再生過程中,細胞增生和分化狀態。最後我描述了長出物(outgrowth)在Monopylephrous前端再生形成的過程。根據我實驗的結果顯示,長出物在切除頭部後的一天內快速形成,在長出物內能觀察到縱肌和神經分佈,在靠近傷口處的舊組織中發現大量的細胞分裂,傷口在第二天變平滑。在第一天到第三天的這段時間,我發現細胞增生的情況會逐漸降低且不集中,甚至在第二天到第三天有長達二十四小時沒有觀察到細胞增生。在第四到第五天這段時間,又能再次觀察到旺盛的細胞分裂,在第五天長出物內開始出現環肌、腹側神經節、神經細胞、食道下神經節和許多神經突處。在第十一天腸道肌肉形成、神經系統也逐漸完整,長出物也分節成五到六個體節。在第十五天,肌肉、和神經系統已相當完整,完成了初步的前端再生。此外我嘗試利用顯微注射的方式將GFP reporter constructs打入Monopylephrous的胚胎中,進行細胞族譜追蹤的實驗。我預期Monopylephrous是個很有潛力成為再生研究領域的新興模式生物。 Regeneration is a widespread phenomenon in the animal kingdom, yet the ability to regenerate lost body parts appears to be highly variable among different animals. In general, most vertebrate animals have less regenerative capacity, which is limited to the repair of certain organs and tissues. On the other hand, many invertebrates, such as planarians and annelids, can regenerate the entire individual from a partial body fragment. Because of this remarkable regeneration capacity, there have been many studies on planarians; however, knowledge on the regeneration of other invertebrate groups is still insufficient. To understand the evolution of animal regeneration mechanisms, I sought to study the regeneration process of annelids, first by asking the following questions: what are the initial cellular events during annelid regeneration? What are the origins of the blastema which forms during annelid regeneration? Are these blastema cells differentiated from certain resident stem cells, like those in the planarian, or derived from terminally differentiated cells via dedifferentiation? To address these questions, I have developed a new experimental animal Monopylephrous, which is a macroscopic aquatic annelid with great regenerative capacity. After the amputation of its anterior nine segments, Monopylephrous can regenerate its entire head within fifteen days. Besides, because of its transparent body wall and easy access to its embryos, Monopylephrous holds great potential for applying transgenic technology to label and trace cells, and for using molecular markers to examine the state of cell proliferation and differentiation during its regeneration process. To this end, I have characterized the process of outgrowth formation during Monopylephrous anterior regeneration. The results showed that after head amputation, outgrowth was quickly formed during the first day and observe longitudinal muscle fibers and axons can be observered in there; additionally, there was strong cell proliferation near the wound. The wound was completely healed by 2-day post-amputation (2 dpa). From 1 to 3 dpa, I observed decreased cell proliferation near outgrowth and within the outgrowth itself. Even during the 2 to 3 dpa, cell proliferation was not detected for up to 24 hours. Besides, from 4 to 5 dpa, cell proliferation increases in the outgrowth and stump again. At 5 dpa I observed that circular muscle fibers, ventral never cord, perikarya, ganglionated ventral nerve cord and more axons in the extend outgrowth. On day 11, there has the gut of muscle and more complete ventral and peripheral never system, outgrowth divide into 5 segments. On day 15, the muscle and nerve system regeneration was almost complete. I am currently using microinjection of GFP reporter constructs into Monopylephrous embryos for cell-lineage tracing experiments. I anticipate that Monopylephrous has the potential to become an emerging model animal for regeneration research. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/8312 |
DOI: | 10.6342/NTU202002519 |
Fulltext Rights: | 同意授權(全球公開) |
metadata.dc.date.embargo-lift: | 2025-08-06 |
Appears in Collections: | 生命科學系 |
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U0001-0608202011442900.pdf Until 2025-08-06 | 14.51 MB | Adobe PDF |
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