Path followed:
- Is the fault in the components that perform any physical action?
Answer: No
- Is the faulty component part of the mechanism’s body?
Answer: Yes
- Is the faulty component in the structure of the mechanism?
Answer: Yes
- Does the fault appear in components that provide rigidity to the mechanism?
Answer: Yes
- Can the faulty component be removed from the mechanism?
Answer: No
- Is the fault in load bearing components?
Answer: Yes
- Do multiple versions of the components exist for the faulty component?
Answer: No
- Can the mechanism continue to function until the component is replaced?
Answer: Yes
31) Tropical clawed frog, Xenopus tropicalis
Tropical clawed frogs can be found in West Africa near freshwater sources (IUCN). Tropical clawed frog tadpoles have the remarkable ability of regenerating their tail if it were amputated.
The tadpoleÕs body is still developing into an adult frog up until metamorphosis which gives it an edge in regeneration since a lot of the cells are still in a stem cell- like state. This state allows the cells to be activated by Wnt, Fgf, Bmp, Notch and TGF-beta pathways and differentiate
into specific cells (Lin & Slack). After the tail is amputated the body produces reactive oxygen species (ROS) which increase the Wnt and Notch signaling (Love et al.). Muscle cells near the wound site proliferate and form a protective covering over the wound called the stump. The signals activate the spinal cord and notochord cells to proliferate and grow the spinal cord into the stump of the tail. The signals also activate muscle satellite cells and melanophore precursors to generate muscle and melanophores, respectively (Lin & Slack). The surrounding tissue cells continue to proliferate and grow the tail to its maximum size. Once the tail has reached its maximum size the cells will continue to differentiate but they will not grow the tail.
IUCN SSC Amphibian Specialist Group 2014. Xenopus tropicalis. The IUCN Red List of Threatened Species. Version 2014.3. Web. 1 Dec. 2014.
http://www.iucnredlist.org/details/58167/0
Lin, Gufa, and Jonathan M.W. Slack. “Requirement for Wnt and FGF Signaling in Xenopus Tadpole Tail Regeneration.” Developmental Biology 316.2 (2008): 323-35. Science Direct. Web. 1 Dec. 2014.
http://www.sciencedirect.com/science/article/pii/S0012160608000766
Love, Nick R., Yaoyao Chen, Shoko Ishibashi, Paraskevi Kritsiligkou, Robert Lea, Yvette Koh, Jennifer L. Gallop, Karel Dorey, and Enrique Amaya. “Amputation-induced Reactive Oxygen Species Are Required for Successful Xenopus Tadpole Tail Regeneration.” Nature Cell Biology 15 (2013): 222-28. Nature Cell Biology. Web. 1 Dec. 2014.
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