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Regeneration (biology)

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Regeneration (biology)

Sun flower sea star regenerates its arms
Dwarf yellow-headed gecko with regenerating tail


  • Spallanzani's mouse: a model of restoration and regeneration
  • Mice that regrow hearts in the news
  • DARPA Grant Supports Research Toward Realizing Tissue Regeneration
  • The Geniuses Of Regeneration in BusinessWeek, May 24, 2004
  • UCI Limb Regeneration Lab
  • A site dedicated to amputation and regeneration

External links

  1. Tanaka EM (October 2003). "Cell differentiation and cell fate during urodele tail and limb regeneration". Curr. Opin. Genet. Dev. 13 (5): 497–501.  
  2. Nye HL, Cameron JA, Chernoff EA, Stocum DL (February 2003). "Regeneration of the urodele limb: a review". Dev. Dyn. 226 (2): 280–94.  
  3. Yu H, Mohan S, Masinde GL, Baylink DJ (December 2005). "Mapping the dominant wound healing and soft tissue regeneration QTL in MRL x CAST". Mamm. Genome 16 (12): 918–24.  
  4. Gardiner DM, Blumberg B, Komine Y, Bryant SV (June 1995). "Regulation of HoxA expression in developing and regenerating axolotl limbs". Development 121 (6): 1731–41.  
  5. Torok MA, Gardiner DM, Shubin NH, Bryant SV (August 1998). "Expression of HoxD genes in developing and regenerating axolotl limbs". Dev. Biol. 200 (2): 225–33.  
  6. Putta S, Smith JJ, Walker JA et al. (August 2004). "From biomedicine to natural history research: EST resources for ambystomatid salamanders". BMC Genomics 5 (1): 54.  
  7. Andrews, Wyatt (March 23, 2008). "Medicine's Cutting Edge: Re-Growing Organs".  


  1. ^ a b Carlson, B. M. (2007). Principles of Regenerative Biology. Elsevier Inc. p. 400.  
  2. ^ Gabor, M. H.; Hotchkiss, R. D. (1979). "Parameters governing bacterial regeneration and genetic recombination after fusion of Bacillus subtilis protoplasts". Journal of Bacteriology 137 (3): 1346–1353.  
  3. ^ a b Min, Su; Wang, Song W.; Orr, William (2006). "Graphic general pathology: 2.2 complete regeneration:". Pathology. Retrieved 2012-12-07. (1) Complete regeneration: The new tissue is the same as the tissue that was lost. After the repair process has been completed, the structure and function of the injured tissue are completely normal 
  4. ^ a b Min, Su; Wang, Song W.; Orr, William (2006). "Graphic general pathology: 2.3 Incomplete regeneration:". Pathology. Retrieved 2012-12-07. The new tissue is not the same as the tissue that was lost. After the repair process has been completed, there is a loss in the structure or function of the injured tissue. In this type of repair, it is common that granulation tissue (stromal connective tissue) proliferates to fill the defect created by the necrotic cells. The necrotic cells are then replaced by scar tissue. 
  5. ^ Himeno, Y.; Engelman, R. W.; Good, R. A. (1992). "Influence of calorie restriction on oncogene expression and DNA synthesis during liver regeneration". Proceedings of the National Academy of Sciences of the United States of America 89 (12): 5497–5501.  
  6. ^ Bryant, P. J.; Fraser, S. E. (1988). "Wound healing, cell communication, and DNA synthesis during imaginal disc regeneration in Drosophila". Developmental Biology 127 (1): 197–208.  
  7. ^ a b Brokes, J. P.; Kumar, A. "Comparative Aspects of Animal Regeneration". Annu. Rev. Cell Dev. Biol. 28: 525–549.  
  8. ^ a b Sánchez, A. A. (2000). "Regeneration in the metazoans: why does it happen?". BioEssays 22 (6): 578–590.  
  9. ^ Reddien, P. W.; Alvarado, A. S. (2004). "Fundamentals of planarian regenerations". Annual Review of Cell and Developmental Biology 20: 725–757.  
  10. ^ Campbell, N. A. Biology (4th ed.). California: The Benjamin Cummings Publishing Company, Inc. p. 1206. 
  11. ^ Wilkie, I. (2001). "Autotomy as a prelude to regeneration in echinoderms". Microscopy Research and Technique 55 (6): 369–396.  
  12. ^ Maiorana, V. C. (1977). "Tail autotomy, functional conflicts and their resolution by a salamander". Nature 2265 (5594): 533–535.  
  13. ^ Maginnis, T. L. (2006). "The costs of autotomy and regeneration in animals: a review and framework for future research". Behavioural Ecology 7 (5): 857–872.  
  14. ^ Dietze, M. C.; Clark, J. S. (2008). "Changing the gap dynamics paradigm: Vegetative regenerative control on forest response to disturbance". Ecological Monographs 78 (3): 331–347.  
  15. ^ Bailey, J. D.; Covington, W. W. (2002). "Evaluation ponderosa pine regeneration rates following ecological restoration treatments in northern Arizona, USA". Forest Ecology and Management 155: 271–278.  
  16. ^ Fu, S. Y.; Gordon, T. (1997). "The cellular and molecular basis of peripheral nerve regeneration". Molecular Neurobiology 14 (1–2): 67–116.  
  17. ^ Akimenko, M.; Johnson, S. L.; Wseterfield, M.; Ekker, M. (1996). homeobox genes during fin development and regeneration in zebrafish"msx"Differential induction of four . Development 121 (2): 347–357.  
  18. ^ a b Alvarado, A. S.; Tsonis, P. A. (2006). "Bridging the regeneration gap: genetic insights from diverse animal models". Nat. Rev. Genet. 7 (11): 873–884.  
  19. ^ Kumar, A.; Godwin, J. W.; Gates, P. B.; Garza-Garcia, A. A.; Brokes, J. P. (2007). "Molecular Basis for the Nerve Dependence of Limb Regeneration in an Adult Vertebrate". Science 318 (5851): 772–7.  
  20. ^ Bely AE (August 2006). "Distribution of segment regeneration ability in the Annelida". Integr. Comp. Biol. 46 (4): 508–18.  
  21. ^ Hill SD (December 1972). "Caudal regeneration in the absence of a brain in two species of sedentary polychaetes". J Embryol Exp Morphol 28 (3): 667–80.  
  22. ^ Giani VC, Yamaguchi E, Boyle MJ, Seaver EC (2011). "Somatic and germline expression of piwi during development and regeneration in the marine polychaete annelid Capitella teleta". Evodevo 2: 10.  
  23. ^ Kragl, M (2009). "Cells keep a memory of their tissue origin during axolotl limb regeneration.". Nature 460 (7251): 60–65.  
  24. ^ Muneoka, K (1986). "Cellular contribution from dermis and cartilage to the regenerating limb blastema in axolotls.". Dev Biol. 116 (1): 256–260.  
  25. ^ Bryant, S (2002). "Vertebrate limb regeneration and the origin of limb stem cells". Int. J. Dev. Biol 46 (7): 887–896.  
  26. ^ Satoh, A; Bryant, SV; Gardiner, DM (2012). "Nerve signaling regulates basal keratinocyte proliferation in the blastema apical epithelial cap in the axolotl (Ambystoma mexicanum).". Dev Biol 15 (366): 374–381.  
  27. ^ Christensen, RN; Tassava, RA (2000). "Apical epithelial cap morphology and fibronectin gene expression in regenerating axolotl limbs.". Dev Dyn 217 (2): 216–224.  
  28. ^ a b Bryant SV, Endo T, Gardiner DM (2002). "Vertebrate limb regeneration and the origin of limb stem cells". The International journal of developmental biology 46 (7): 887–96.  
  29. ^ Mullen LM, Bryant SV, Torok MA, Blumberg B, Gardiner DM (November 1996). "Nerve dependency of regeneration: the role of Distal-less and FGF signaling in amphibian limb regeneration". Development (Cambridge, England) 122 (11): 3487–97.  
  30. ^ Endo T, Bryant SV, Gardiner DM (June 2004). "A stepwise model system for limb regeneration". Developmental Biology 270 (1): 135–45.  
  31. ^
  32. ^ Souppouris, Aaron (2013-05-23). "Scientists identify cell that could hold the secret to limb regeneration". the Macrophages are a type of repairing cell that devour dead cells and pathogens, and trigger other immune cells to respond to pathogens. 
  33. ^ "Do Salamanders' Immune Systems Hold the Key to Regeneration?". ScienceDaily. Retrieved 21 May 2013. 
  34. ^ Bedelbaeva K, Snyder A, Gourevitch D, Clark L, Zhang X-M, Leferovich J, Cheverud JM, Lieberman P, Heber-Katz E; Snyder; Gourevitch; Clark; Zhang; Leferovich; Cheverud; Lieberman; Heber-Katz (March 2010). "Lack of p21 expression links cell cycle control and appendage regeneration in mice". Proceedings of the National Academy of Sciences 107 (11): 5845–50.  
  35. ^ Humans Could Regenerate Tissue Like Newts By Switching Off a Single Gene
  36. ^ Ashley W. Seifert, Stephen G. Kiama et al (2011-11-27). "Skin shedding and tissue regeneration in African spiny mice (Acomys)". Nature 489. pp. 561–565.  
  37. ^
  38. ^ Becker RO (Jan 1972). "Stimulation of Partial Limb Regeneration in Rats". Nature 235 (14): 109–111.  
  39. ^ Becker RO (May 1972). "Electrical stimulation of partial limb regeneration in mammals". Bull N Y Acad Med 48 (4): 627–41.  
  40. ^ Masinde G, Li X, Baylink DJ, Nguyen B, Mohan S (April 2005). "Isolation of wound healing/regeneration genes using restrictive fragment differential display-PCR in MRL/MPJ and C57BL/6 mice". Biochemical and Biophysical Research Communications 330 (1): 117–22.  
  41. ^ Mansuo L. Hayashi, B. S. Shankaranarayana Rao, Jin-Soo Seo, Han-Saem Choi, Bridget M. Dolan, Se-Young Choi, Sumantra Chattarji, and Susumu Tonegawa; Rao; Seo; Choi; Dolan; Choi; Chattarji; Tonegawa (July 2007). "Inhibition of p21-activated kinase rescues symptoms of fragile X syndrome in mice". Proceedings of the National Academy of Sciences 104 (27): 11489–94.  
  42. ^ Abdullah I, Lepore JJ, Epstein JA, Parmacek MS, Gruber PJ (Mar–April 2005). "MRL mice fail to heal the heart in response to ischemia-reperfusion injury". Wound Repair Regen 13 (2): 205–208.  
  43. ^ Min, Su; Wang, Song W.; Orr, William (2006). "Graphic general pathology: 2.2 complete regeneration:". Pathology. Retrieved 2013-11-10. After the repair process has been completed, the structure and function of the injured tissue are completely normal. This type of regeneration is common in physiological situations. Examples of physiological regeneration are the continual replacement of cells of the skin and repair of the endometrium after menstruation. Complete regeneration can occur in pathological situations in tissues that have good regenerative capacity. 


See also

The regrowth of lost tissues or organs in the human body is being researched. Some tissues such as skin regrow quite readily; others have been thought to have little or no capacity for regeneration, but ongoing research suggests that there is some hope for a variety of tissues and organs.[43]


The regenerative ability of MRL mice does not, however, protect them against myocardial infarction; heart regeneration in adult mammals (neocardiogenesis) is limited, because heart muscle cells are nearly all terminally differentiated. MRL mice show the same amount of cardiac injury and scar formation as normal mice after a heart attack.[42] However, recent studies provide evidence that this may not always be the case, and that MRL mice can regenerate after heart damage. [1]

By comparing the differential gene expression of scarless healing MRL mice and a poorly-healing C57BL/6 mouse strain, 36 genes have been identified that are good candidates for studying how the healing process differs in MRL mice and other mice.[40][41]

The MRL mouse is a strain of mouse that exhibits remarkable regenerative abilities for a mammal. Study of the regenerative process in these animals is aimed at discovering how to duplicate them in humans.

Adult mammals have limited regenerative capacity compared to most vertebrate embryos/larvae, adult salamanders and fish.[37] But the regeneration therapy approach of Robert O. Becker, using electrical stimulation, has shown promising results for rats [38] and mammals in general.[39]

At least two species of African Spiny Mice, Acomys kempi and Acomys percivali, are capable of completely regenerating the autotomically released or otherwise damaged tissue. These species can regrow hair follicles, skin, sweat glands, fur and cartilage.[36]

The mechanism for regeneration in Murphy Roths Large (MRL) mice has been found, and is related to the deactivation of the p21 gene.[34][35]


Researchers at Australian Regenerative Medicine Institute at Monash University, have published that when macrophages, which eat up material debris,[32] were removed, salamanders lost their ability to regenerate and formed scarred tissue instead.[33]

In spite of the historically few researchers studying limb regeneration, remarkable progress has been made recently in establishing the neotenous amphibian the axolotl (Ambystoma mexicanum) as a model genetic organism. This progress has been facilitated by advances in genomics, bioinformatics, and somatic cell transgenesis in other fields, that have created the opportunity to investigate the mechanisms of important biological properties, such as limb regeneration, in the axolotl.[30] The Ambystoma Genetic Stock Center (AGSC) is a self-sustaining, breeding colony of the axolotl supported by the National Science Foundation as a Living Stock Collection. Located at the University of Kentucky, the AGSC is dedicated to supplying genetically well-characterized axolotl embryos, larvae, and adults to laboratories throughout the United States and abroad. An NIH-funded NCRR grant has led to the establishment of the Ambystoma EST database, the Salamander Genome Project (SGP) that has led to the creation of the first amphibian gene map and several annotated molecular data bases, and the creation of the research community web portal.[31]

After amputation, the epidermis migrates to cover the stump in 1-2 hours, forming a structure called the wound epithelium (WE).[26] Epidermal cells continue to migrate over the WE, resulting in a thickened, specialized signaling center called the apical epithelial cap (AEC).[27] Over the next several days there are changes in the underlying stump tissues that result in the formation of a blastema (a mass of dedifferentiated proliferating cells). As the blastema forms, pattern formation genes – such as HoxA and HoxD – are activated as they were when the limb was formed in the embryo.[28][29] The positional identity of the distal tip of the limb (i.e. the autopod, which is the hand or foot) is formed first in the blastema. Intermediate positional identities between the stump and the distal tip are then filled in through a process called intercalation.[28] Motor neurons, muscle, and blood vessels grow with the regenerated limb, and reestablish the connections that were present prior to amputation. The time that this entire process takes varies according to the age of the animal, ranging from about a month to around three months in the adult and then the limb becomes fully functional.

Axolotls can regenerate a variety of structures, including their limbs

Limb regeneration in salamanders occurs in two major steps. First, adult cells dedifferentiate into progenitor cells which will replace the tissues they are derived from.[23][24] Second, these progenitor cells then proliferate and differentiate until they have completely replaced the missing structure.[25]

Simple animals like planarians have an enhanced capacity to regenerate because the adults retain clusters of stem cells (salamanders possess strong powers of regeneration, which begins immediately after amputation. Limb regeneration in the axolotl and newt has been extensively studied and researched.


Planarians exhibit an extraordinary ability to regenerate lost body parts. For example, a planarian split lengthwise or crosswise will regenerate into two separate individuals. In one experiment, T. H. Morgan found that a piece corresponding to 1⁄279th of a planarian could successfully regenerate into a new worm. This size (about 10,000 cells) is typically accepted as the smallest fragment that can regrow into a new planarian. Regeneration of planaria is epimorphic regeneration. After amputation, stump cells form blastema.

Planaria (Platyhelminthes)

Many annelids are capable of regeneration.[20] For example, Chaetopterus variopedatus and Branchiomma nigromaculata can regenerate both anterior and posterior body parts after latitudinal bisection.[21] The relationship between somatic and germline stem cell regeneration has been studied at the molecular level in the annelid Capitella teleta.[22]


In animals

"Strategies include the rearrangement of pre-existing tissue, the use of adult blastema, which is "a mound of stem cells from which regeneration begins."[19] Dedifferentiation of cells means that they lose their tissue-specific characteristics as tissues remodel during the regeneration process. This should not be confused with the transdifferentiation of cells which is when they lose their tissue-specific characteristics during the regeneration process, and then re-differentiate to a different kind of cell.[18]


Pattern formation in the morphogenesis of an animal is regulated by genetic induction factors that put cells to work after damage has occurred. Neural cells, for example, express growth-associated proteins, such as GAP-43, tubulin, actin, an array of novel neuropeptides, and cytokines that induce a cellular physiological response to regenerate from the damage.[16] Many of the genes that are involved in the original development of tissues are reinitialized during the regenerative process. Cells in the primordia of zebrafish fins, for example, express four genes from the homeobox msx family during development and regeneration.[17]

Cellular molecular fundamentals


  • Cellular molecular fundamentals 1
  • Tissues 2
  • In animals 3
    • Annelida 3.1
    • Planaria (Platyhelminthes) 3.2
    • Amphibians 3.3
    • Mammals 3.4
    • Humans 3.5
  • See also 4
  • Notes 5
  • Sources 6
  • External links 7

The metazoan creatures.[8] In a related context, some animals are able to reproduce asexually through fragmentation, budding, or fission.[7] A planarian parent, for example, will constrict, split in the middle, and each half generates a new end to form two clones of the original.[10] Echinoderms (such as the starfish), crayfish, many reptiles, and amphibians exhibit remarkable examples of tissue regeneration. The case of autotomy, for example, serves as a defensive function as the animal detaches a limb or tail to avoid capture. After the limb or tail has been autotomized, cells move into action and the tissues will regenerate.[11][12][13] Ecosystems are regenerative as well. Following a disturbance, such as a fire or pest outbreak in a forest, pioneering species will occupy, compete for space, and establish themselves in the newly opened habitat. The new growth of seedlings and community assembly process is known as regeneration in ecology.[14][15]

. budding perform regeneration but reproduce by the method of hydra. For example, reproduction Regeneration is different from [7]

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