Limb Regeneration In Salamanders

Journal of Herpetology

Limb Regeneration in Salamanders

By: Marcos Alberto

Methods of Writing for Biology

Dr. Welsh – May 2, 2014

Introduction:

On account of their unique anatomy and physiology, ecology, and behavior, salamanders make for the most fit subjects for many scientific experiments and research studies. More specifically the axolotl Ambystoma mexicanun is one of the most commonly used model organisms in developmental and regenerative studies because it can regenerate a completely normal and functional fore or hind limb after it has been amputated. [1] There are many other amphibians that have the ability to regenerate lost limbs, the way it works is after the amputation the new cells start to appear on the spot and form what is called a regeneration blastema. The limb blastema recreates an almost perfect copy of the original limb giving the organism full use and function of it.

Salamanders are nocturnal creatures that prefer to live in water or as close to it as possible considering their skin requires constant moisture in order for them to stay alive. Due to the destruction of wetlands and habitat degradation it poses big threats to biodiversity, especially among amphibians. [11] Considering that salamanders aren’t usually bigger than a few inches long, they do not require huge amounts of food. Salamanders can get by eating insects such as spiders, bugs, worms, etc. Their biggest predators are crayfish and just fish in general that are bigger than the salamanders usually try to eat them.

Studies are frequently made in order to narrow down exactly what gives salamanders and some species of fish the ability to regenerate lost limbs. The results show that through reprogramming different cells, proliferation and...

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.... Here the Cre-loxP genetic fate mapping will be applied to skeletal muscle during limb regeneration in two salamander species, Notophthalmus viridescens (newt) and Ambystoma mexicanum (axolotl). It is known that myofiber dedifferentiation is an integral part of limb regeneration in the newt, but not in axolotl. In the newt, myofiber fragmentation results in proliferating, PAX7(-) mononuclear cells in the blastema that give rise to the skeletal muscle in the new limb. In contrast, myofibers in axolotl do not generate proliferating cells, and do not contribute to newly regenerated muscle; instead, resident PAX7(+) cells provide the regeneration activity.[5] Results show significant diversity in limb muscle regeneration mechanisms among salamanders and suggest that multiple strategies may be feasible for inducing regeneration in other species, including mammals.[5]