Studies On Glycogen, Glycogen Synthetase and Respiratory Quotient in the Normal and Regenerating Tail of the House Lizard, Hemidactylus Flaviviridis

Shah, Rushabh; Hiradhar, P. K.

doi:10.1163/002829674x00110

Cited by 11 publications

(11 citation statements)

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“…During anaerobic glycolysis occurring in tail muscles, glycogen converts into lactate and provides the energy required for muscle activity (Shah and Hiradhar 1974). In resting tail muscles, glycogen was found at levels similar to those in whole-body muscles (average resting tail glycogen p vs. 8.2 mg/g in Podarcis hind limb muscle; Hailey et al 7.5 1987).…”

Section: Discussionmentioning

confidence: 94%

Comparative Postautotomy Tail Activity in Six Mediterranean Lacertid Lizard Species

Pafilis¹,

Valakos²,

Foufopoulos³

2005

Physiological and Biochemical Zoology

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Tail autotomy, the self-induced tail separation from the body, is a common and effective antipredator mechanism in lizards. In this study, we examine the muscle energetics of tail shedding in six lacertid lizard species (Podarcis erhardii, Podarcis peloponnesiaca, Podarcis muralis, Podarcis gaigeae, Podarcis milensis, and Lacerta graeca) from the northeast Mediterranean region. Very long periods of postautotomy tail movement were demonstrated for all species ( min), and differences range p 6-8 among species were not statistically significant. Postautotomy tail movement, powered by anaerobic muscle activity, resulted in a strong increase in lactate concentrations and a concomitant depletion of muscle glycogen of exhausted tails relative to resting tails. No significant differences were found in either lactate or glycogen concentrations among the species examined. Duration of movement was negatively correlated with final lactate concentrations. The lack of differentiation in postautotomy energetic physiology in this group of species that have evolved under very different predation environments indicates that postautotomy muscle metabolism involves an overall conservative suite of characters.

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Section: Discussionmentioning

confidence: 94%

Comparative Postautotomy Tail Activity in Six Mediterranean Lacertid Lizard Species

Pafilis¹,

Valakos²,

Foufopoulos³

2005

Physiological and Biochemical Zoology

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“…The regenerative blastema is very rich in water, more than 80%, and in hyaluronate (Shah and Hiradhar, , ; Nambiar et al, ; Alibardi, , , ; Fig. F), recreating a typical embryonic organ where cells can proliferate, move, and aggregate into new tissues while the apical tip continues to growth.…”

Section: The Lizard Blastema As An Amniote Model Of Appendages Regenementioning

confidence: 99%

Review: The Regenerating Tail Blastema of Lizards as a Model to Study Organ Regeneration and Tumor Growth Regulation in Amniotes

Alibardi

2018

The Anatomical Record

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Tail regeneration in lizards is a unique case of organ regeneration among amniotes. The Review summarizes past and recent studies indicating that tail regeneration utilizes numerous signaling pathways typical for tumor growth. The regenerative blastema-cone contains sparse proliferating cells that utilize coding and noncoding RNAs in an environment rich in water and hyaluronate, as typical for tumor outgrowth. Differently from tumors, the blastema appears as a polarized outgrowth where the distal region contains proliferating cells mainly driven by the up-regulation of Wnt, snoRNAs, and associated onco-genes. The down-regulation of immune-genes coupled with the high production of hyaluronate coating blastema cells likely protect them from attach by immune cells. Immunoevasion of blastema cells allows the proliferation and migration necessary for the morphogenesis of a new tail. Transcriptome and immunolabeling data suggest that gradients for wnts, shh, msx, and signaling receptors are present in the tail blastema. It is hypothesized that cells along these gradients activate different genes, including tumor suppressors that are expressed in more proximal regions where cells stop proliferating and differentiate into tissues of the new tail. The continuous proliferation at the apex of the blastema is turned into a regulated growth in more proximal regions near the original tail. In contrast, it is hypothesized that no or nonresponding gradients of signaling proteins are present in tumor outgrowths so that cell proliferation but no differentiation occurs in expanding tumors. Considering signaling gradients, the lizard model of regeneration can help in understanding the lack of regulation of tumor growth.

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“…The determination of the water content in the limbs of lizards, newt, and frog tadpoles also shows an average of 10–20% more water content in tissues of amphibians (Alibardi, ; Figure ). During tail and limb regeneration in lizards, the water content increases further (Shah and Hiradhar, ; Alibardi, ), less dramatically in newts, while it remains similar and very high in frog tadpoles (Figure ). In normal tail of lizards ( Podarcis sicula and Tarentola mauritanica ), the normal level of hydration, 65–70%, jumps to 82–84% at the blastema‐cone stage, which is in the average range, 80–84%, detected in vertebrate embryos (Gray, ; Broberg and Kristoffersson, ), or over 90% in frog embryos (Tattersall and Wright, ).…”

Section: Appendages Regeneration Occurs In a Hydrated Hyaluronate‐rimentioning

confidence: 99%

Hyaluronic acid in the tail and limb of amphibians and lizards recreates permissive embryonic conditions for regeneration due to its hygroscopic and immunosuppressive properties

Alibardi

2017

J Exp Zool Pt B

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The present review focuses on the role of hyaluronate (hyaluronic acid; HA) during limb and tail regeneration in amphibians and lizards mainly in relation to cells of the immune system. This non-sulfated glycosaminoglycan (GAG) increases in early stages of wound healing and blastema formation, like during limb or tail embryogenesis, when the immune system is still immature. The formation of a regenerating blastema occurs by the accumulation of mesenchymal cells displaying embryonic-like antigens and HA. This GAG adsorbs large amount of water and generates a soft tissue over 80% hydrated where mesenchymal and epithelial cells can move and interact, an obligatory passage for organ regeneration. GAGs and HA in particular rise to a high amount and coat plasma membranes of blastema cells forming a shield that likely impedes to the circulating immune cells to elicit an immune reaction against the embryonic-like antigens present on blastema cells. The evolution of limb-tail regeneration in amphibians dates back to the Devonian-Carboniferous, while tail regeneration in lizards is a more recent evolution process, possibly occurred since the Jurassic, which is unique among amniotes. Both processes are associated with the reactivation of proliferating embryonic programs that involve the upregulation of genes for Wnt, non-coding RNAs, and HA synthesis in an immune-suppress organ, the regenerative blastema. Failure of maintaining a lasting HA synthesis for the formation of a highly hydrated blastema leads to scarring, the common healing process of amniotes equipped with an efficient immune system. The study of amphibian and lizard regeneration indicates that attempts to stimulate organ regeneration in other vertebrates require the induction of a highly hydrated and immune-depressed, HA-rich environment, similar to the extracellular environment present during development.

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Studies On Glycogen, Glycogen Synthetase and Respiratory Quotient in the Normal and Regenerating Tail of the House Lizard, Hemidactylus Flaviviridis

Cited by 11 publications

References 0 publications

Comparative Postautotomy Tail Activity in Six Mediterranean Lacertid Lizard Species

Comparative Postautotomy Tail Activity in Six Mediterranean Lacertid Lizard Species

Review: The Regenerating Tail Blastema of Lizards as a Model to Study Organ Regeneration and Tumor Growth Regulation in Amniotes

Hyaluronic acid in the tail and limb of amphibians and lizards recreates permissive embryonic conditions for regeneration due to its hygroscopic and immunosuppressive properties

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